外文翻译----数字图像处理与边缘检测
数字图像处理外文翻译参考文献
数字图像处理外文翻译参考文献(文档含中英文对照即英文原文和中文翻译)原文：Application Of Digital Image Processing In The MeasurementOf Casting Surface RoughnessAhstract- This paper presents a surface image acquisition system based on digital image processing technology. The image acquired by CCD is pre-processed through the procedure of image editing, image equalization, the image binary conversation and feature parameters extraction to achieve casting surface roughness measurement. The three-dimensional evaluation method is taken to obtain the evaluation parametersand the casting surface roughness based on feature parameters extraction. An automatic detection interface of casting surface roughness based on MA TLAB is compiled which can provide a solid foundation for the online and fast detection of casting surface roughness based on image processing technology.Keywords-casting surface; roughness measurement; image processing; feature parametersⅠ.INTRODUCTIONNowadays the demand for the quality and surface roughness of machining is highly increased, and the machine vision inspection based on image processing has become one of the hotspot of measuring technology in mechanical industry due to their advantages such as non-contact, fast speed, suitable precision, strong ability of anti-interference, etc [1,2]. As there is no laws about the casting surface and the range of roughness is wide, detection parameters just related to highly direction can not meet the current requirements of the development of the photoelectric technology, horizontal spacing or roughness also requires a quantitative representation. Therefore, the three-dimensional evaluation system of the casting surface roughness is established as the goal [3,4], surface roughness measurement based on image processing technology is presented. Image preprocessing is deduced through the image enhancement processing, the image binary conversation. The three-dimensional roughness evaluation based on the feature parameters is performed . An automatic detection interface of casting surface roughness based on MA TLAB is compiled which provides a solid foundation for the online and fast detection of casting surface roughness.II. CASTING SURFACE IMAGE ACQUISITION SYSTEMThe acquisition system is composed of the sample carrier, microscope, CCD camera, image acquisition card and the computer. Sample carrier is used to place tested castings. According to the experimental requirements, we can select a fixed carrier and the sample location can be manually transformed, or select curing specimens and the position of the sampling stage can be changed. Figure 1 shows the whole processing procedure.,Firstly,the detected castings should be placed in the illuminated backgrounds as far as possible, and then through regulating optical lens, setting the CCD camera resolution and exposure time, the pictures collected by CCD are saved to computer memory through the acquisition card. The image preprocessing and feature value extraction on casting surface based on corresponding software are followed. Finally the detecting result is output.III. CASTING SURFACE IMAGE PROCESSINGCasting surface image processing includes image editing, equalization processing, image enhancement and the image binary conversation,etc. The original and clipped images of the measured casting is given in Figure 2. In which a) presents the original image and b) shows the clipped image.A.Image EnhancementImage enhancement is a kind of processing method which can highlight certain image information according to some specific needs and weaken or remove some unwanted informations at the same time[5].In order to obtain more clearly contour of the casting surface equalization processing of the image namely the correction of the image histogram should be pre-processed before image segmentation processing. Figure 3 shows the original grayscale image and equalization processing image and their histograms. As shown in the figure, each gray level of the histogram has substantially the same pixel point and becomes more flat after gray equalization processing. The image appears more clearly after the correction and the contrast of the image is enhanced.Fig.2 Casting surface imageFig.3 Equalization processing imageB. Image SegmentationImage segmentation is the process of pixel classification in essence. It is a very important technology by threshold classification. The optimal threshold is attained through the instmction thresh = graythresh (II). Figure 4 shows the image of the binary conversation. The gray value of the black areas of the Image displays the portion of the contour less than the threshold (0.43137), while the white area shows the gray value greater than the threshold. The shadows and shading emerge in the bright region may be caused by noise or surface depression.Fig4 Binary conversationIV. ROUGHNESS PARAMETER EXTRACTIONIn order to detect the surface roughness, it is necessary to extract feature parameters of roughness. The average histogram and variance are parameters used to characterize the texture size of surface contour. While unit surface's peak area is parameter that can reflect the roughness of horizontal workpiece.And kurtosis parameter can both characterize the roughness of vertical direction and horizontal direction. Therefore, this paper establisheshistogram of the mean and variance, the unit surface's peak area and the steepness as the roughness evaluating parameters of the castings 3D assessment. Image preprocessing and feature extraction interface is compiled based on MATLAB. Figure 5 shows the detection interface of surface roughness. Image preprocessing of the clipped casting can be successfully achieved by this software, which includes image filtering, image enhancement, image segmentation and histogram equalization, and it can also display the extracted evaluation parameters of surface roughness.Fig.5 Automatic roughness measurement interfaceV. CONCLUSIONSThis paper investigates the casting surface roughness measuring method based on digital Image processing technology. The method is composed of image acquisition, image enhancement, the image binary conversation and the extraction of characteristic parameters of roughness casting surface. The interface of image preprocessing and the extraction of roughness evaluation parameters is compiled by MA TLAB which can provide a solid foundation for the online and fast detection of casting surface roughness.REFERENCE[1] Xu Deyan, Lin Zunqi. The optical surface roughness research pro gress and direction[1]. Optical instruments 1996, 18 (1): 32-37.[2] Wang Yujing. Turning surface roughness based on image measurement [D]. Harbin:Harbin University of Science and Technology[3] BRADLEY C. Automated surface roughness measurement[1]. The InternationalJournal of Advanced Manufacturing Technology ,2000,16(9) :668-674.[4] Li Chenggui, Li xing-shan, Qiang XI-FU 3D surface topography measurement method[J]. Aerospace measurement technology, 2000, 20(4): 2-10.[5] Liu He. Digital image processing and application [ M]. China Electric Power Press,2005译文：数字图像处理在铸件表面粗糙度测量中的应用摘要—本文提出了一种表面图像采集基于数字图像处理技术的系统。
图像处理-毕设论文外文翻译(翻译+原文)
英文资料翻译Image processing is not a one step process．We are able to distinguish between several steps which must be performed one after the other until we can extract the data of interest from the observed scene．In this way a hierarchical processing scheme is built up as sketched in Fig．The figure gives an overview of the different phases of image processing.Image processing begins with the capture of an image with a suitable，not necessarily optical，acquisition system．In a technical or scientific application，we may choose to select an appropriate imaging system．Furthermore，we can set up the illumination system，choose the best wavelength range，and select other options to capture the object feature of interest in the best way in an image．Once the image is sensed，it must be brought into a form that can be treated with digital computers.This process is called digitization.With the problems of traffic are more and more serious. Thus Intelligent Transport System (ITS) comes out. The subject of the automatic recognition of license plate is one of the most significant subjects that are improved from the connection of computer vision and pattern recognition. The image imputed to the computer is disposed and analyzed in order to localization the position and recognition the characters on the license plate express these characters in text string form The license plate recognition system (LPSR) has important application in ITS. In LPSR, the first step is for locating the license plate in the captured image which is very important for character recognition. The recognition correction rate of license plate is governed by accurate degree of license plate location. In this paper, several of methods in image manipulation are compared and analyzed, then come out the resolutions for localization of the car plate. The experiences show that the good result has been got with these methods. The methods based on edge map and frequency analysis is used in the process of the localization of the license plate, that is to say, extracting the characteristics of the license plate in the car images after being checked up forthe edge, and then analyzing and processing until the probably area of license plate is extracted.The automated license plate location is a part of the image processing ,it’s also an important part in the intelligent traffic system．It is the key step in the Vehicle License Plate Recognition(LPR).A method for the recognition of images of different backgrounds and different illuminations is proposed in the paper.the upper and lower borders are determined through the gray variation regulation of the character distribution.The left and right borders are determined through the black-white variation of the pixels in every row.The first steps of digital processing may include a number of different operations and are known as image processing．If the sensor has nonlinear characteristics, these need to be corrected．Likewise，brightness and contrast of the image may require improvement．Commonly，too，coordinate transformations are needed to restore geometrical distortions introduced during image formation．Radiometric and geometric corrections are elementary pixel processing operations．It may be necessary to correct known disturbances in the image，for instance caused by a defocused optics，motion blur，errors in the sensor，or errors in the transmission of image signals．We also deal with reconstruction techniques which are required with many indirect imaging techniques such as tomography that deliver no direct image.A whole chain of processing steps is necessary to analyze and identify objects．First，adequate filtering procedures must be applied in order to distinguish the objects of interest from other objects and the background．Essentially，from an image（or several images），one or more feature images are extracted．The basic tools for this task are averaging and edge detection and the analysis of simple neighborhoods and complex patterns known as texture in image processing．An important feature of an object is also its motion．Techniques to detect and determine motion are necessary．Then the object has to be separated from the background．This means that regions of constant features and discontinuities must be identified．This process leads to alabel image．Now that we know the exact geometrical shape of the object，we can extract further information such as the mean gray value，the area，perimeter，and other parameters for the form of the object[3]．These parameters can be used to classify objects．This is an important step in many applications of image processing，as the following examples show：In a satellite image showing an agricultural area，we would like to distinguish fields with different fruits and obtain parameters to estimate their ripeness or to detect damage by parasites．There are many medical applications where the essential problem is to detect pathologi-al changes．A classic example is the analysis of aberrations in chromosomes．Character recognition in printed and handwritten text is another example which has been studied since image processing began and still poses significant difficulties．You hopefully do more，namely try to understand the meaning of what you are reading．This is also the final step of image processing，where one aims to understand the observed scene．We perform this task more or less unconsciously whenever we use our visual system．We recognize people，we can easily distinguish between the image of a scientific lab and that of a living room，and we watch the traffic to cross a street safely．We all do this without knowing how the visual system works．For some times now，image processing and computer-graphics have been treated as two different areas．Knowledge in both areas has increased considerably and more complex problems can now be treated．Computer graphics is striving to achieve photorealistic computer-generated images of three-dimensional scenes，while image processing is trying to reconstruct one from an image actually taken with a camera．In this sense，image processing performs the inverse procedure to that of computer graphics．We start with knowledge of the shape and features of an object—at the bottom of Fig. and work upwards until we get a two-dimensional image．To handle image processing or computer graphics，we basically have to work from the same knowledge．We need to know the interaction between illumination and objects，how a three-dimensional scene is projected onto an image plane，etc．There are still quite a few differences between an image processing and a graphics workstation．But we can envisage that，when the similarities and interrelations between computergraphics and image processing are better understood and the proper hardware is developed，we will see some kind of general-purpose workstation in the future which can handle computer graphics as well as image processing tasks[5]．The advent of multimedia，i. e. ，the integration of text，images，sound，and movies，will further accelerate the unification of computer graphics and image processing.In January 1980 Scientific American published a remarkable image called Plume2，the second of eight volcanic eruptions detected on the Jovian moon by the spacecraft Voyager 1 on 5 March 1979．The picture was a landmark image in interplanetary exploration—the first time an erupting volcano had been seen in space．It was also a triumph for image processing．Satellite imagery and images from interplanetary explorers have until fairly recently been the major users of image processing techniques，where a computer image is numerically manipulated to produce some desired effect-such as making a particular aspect or feature in the image more visible.Image processing has its roots in photo reconnaissance in the Second World War where processing operations were optical and interpretation operations were performed by humans who undertook such tasks as quantifying the effect of bombing raids．With the advent of satellite imagery in the late 1960s，much computer-based work began and the color composite satellite images，sometimes startlingly beautiful, have become part of our visual culture and the perception of our planet．Like computer graphics，it was until recently confined to research laboratories which could afford the expensive image processing computers that could cope with the substantial processing overheads required to process large numbers of high-resolution images．With the advent of cheap powerful computers and image collection devices like digital cameras and scanners，we have seen a migration of image processing techniques into the public domain．Classical image processing techniques are routinely employed bygraphic designers to manipulate photographic and generated imagery，either to correct defects，change color and so on or creatively to transform the entire look of an image by subjecting it to some operation such as edge enhancement.A recent mainstream application of image processing is the compression of images—either for transmission across the Internet or the compression of moving video images in video telephony and video conferencing．Video telephony is one of the current crossover areas that employ both computer graphics and classical image processing techniques to try to achieve very high compression rates．All this is part of an inexorable trend towards the digital representation of images．Indeed that most powerful image form of the twentieth century—the TV image—is also about to be taken into the digital domain．Image processing is characterized by a large number of algorithms that are specific solutions to specific problems．Some are mathematical or context-independent operations that are applied to each and every pixel．For example，we can use Fourier transforms to perform image filtering operations．Others are“algorithmic”—we may use a complicated recursive strategy to find those pixels that constitute the edges in an image．Image processing operations often form part of a computer vision system．The input image may be filtered to highlight or reveal edges prior to a shape detection usually known as low-level operations．In computer graphics filtering operations are used extensively to avoid abasing or sampling artifacts．中文翻译图像处理不是一步就能完成的过程。
外文翻译---基于模糊逻辑技术图像上边缘检测
译文二：1基于模糊逻辑技术图像上边缘检测[2]摘要：模糊技术是经营者为了模拟在数学水平的代偿行为过程的决策或主观评价而引入的。
下面介绍经营商已经完成了的计算机视觉应用。
本文提出了一种基于模糊逻辑推理战略为基础的新方法，它被建议使用在没有确定阈值的数字图像边缘检测上。
这种方法首先将用3⨯3的浮点二进制矩阵将图像分割成几个区域。
边缘像素被映射到一个属性值与彼此不同的范围。
该方法的鲁棒性所得到的不同拍摄图像将与线性Sobel运算所得到的图像相比较。
并且该方法给出了直线的线条平滑度、平直度和弧形线条的良好弧度这些永久的效果。
同时角位可以更清晰并且可以更容易的定义。
关键词：模糊逻辑，边缘检测，图像处理，电脑视觉，机械的部位，测量1.引言在过去的几十年里，对计算机视觉系统的兴趣，研究和发展已经增长了不少。
如今，它们出现在各个生活领域，从停车场，街道和商场各角落的监测系统到主要食品生产的分类和质量控制系统。
因此，引进自动化的视觉检测和测量系统是有必要的，特别是二维机械对象[1,8]。
部分原因是由于那些每天产生的数字图像大幅度的增加(比如，从X光片到卫星影像)，并且对于这样图片的自动处理有增加的需求[9,10,11]。
因此，现在的许多应用例如对医学图像进行计算机辅助诊断，将遥感图像分割和分类成土地类别(比如，对麦田，非法大麻种植园的鉴定，以及对作物生长的估计判断)，光学字符识别，闭环控制，基于目录检索的多媒体应用，电影产业上的图像处理，汽车车牌的详细记录的鉴定，以及许多工业检测任务(比如，纺织品，钢材，平板玻璃等的缺陷检测)。
历史上的许多数据已经被生成图像，以帮助人们分析(相比较于数字表之类的，图像显然容易理解多了)[12]。
所以这鼓励了数字分析技术在数据处理方面的使用。
此外，由于人类善于理解图像，基于图像的分析法在算法发展上提供了一些帮助(比如，它鼓励几何分析)，并且也有助于非正式确认的结果。
虽然计算机视觉可以被总结为一个自动(或半自动)分析图像的系统，一些变化也是可能的[9,13]。
数字图像处理常用词汇表
数字图像处理常用词汇表Binary image 二值图像Blur 模糊Boundary pixel 边界像素Boundary tracking 边界跟踪Closed curve 封闭曲线color model 彩色模型complex conjugate复共轭Connected 连通的Curve 曲线4-neighbors 4邻域8-neighbors 8邻域4-adjacency 4邻接8-adjacency 8邻接Path 路径Dilation 膨胀Erosion 腐蚀Opening 开运算（先腐蚀，后膨胀）Closing 闭运算（先膨胀，后腐蚀）Structuring element 结构元素DFT 离散的傅立叶变换Inverse DFT 逆离散的傅立叶变换Digital image 数字图像Digital image processing 数字图像处理Digitization 数字化Edge 边缘Edge detection 边缘检测Edge enhancement 边缘增强Edge image 边缘图像Edge operator 边缘算子Edge pixel 边缘像素Enhance 增强Fourier transform 傅立叶变换Gray level 灰度级别Gray scale 灰度尺度Horizontal edge 水平边缘Highpass filtering 高通滤波Lowpass filtering 低通滤波Image restoration 图像复原Image segmentation 图像分割Inverse transformation 逆变换Line detection 线检测Line pixel 直线像素Linear filter线性滤波Median filter中值滤波Mask 掩模Neighborhood 邻域Neighborhood operation 邻域运算Noise 噪音Noise reduction 噪音消减Pixel 像素Point operation 点运算Region 区域Region averaging 区域平均Weighted region averaging加权区域平均Resolution 分辨率Sharpening 锐化Shape number 形状数Smoothing 平滑Threshold 阈值Thresholding 二值化Transfer function 传递函数Vertical edge 垂直边缘Horizontal edge 水平边缘RGB color cube RGB色彩立方体HSI color model HSI 色彩模型Circular color plane 圆形彩色平面Triangular color plane 三角形彩色平面。
数字图像处理英文文献翻译参考
…………………………………………………装………………订………………线…………………………………………………………………Hybrid Genetic Algorithm Based Image EnhancementTechnologyMu Dongzhou Department of the Information Engineering XuZhou College of Industrial TechnologyXuZhou, China ****************.cnXu Chao and Ge Hongmei Department of the Information Engineering XuZhou College of Industrial TechnologyXuZhou, China ***************.cn,***************.cnAbstract—in image enhancement, Tubbs proposed a normalized incomplete Beta function to represent several kinds of commonly used non-linear transform functions to do the research on image enhancement. But how to define the coefficients of the Beta function is still a problem. We proposed a Hybrid Genetic Algorithm which combines the Differential Evolution to the Genetic Algorithm in the image enhancement process and utilize the quickly searching ability of the algorithm to carry out the adaptive mutation and searches. Finally we use the Simulation experiment to prove the effectiveness of the method.Keywords- Image enhancement; Hybrid Genetic Algorithm; adaptive enhancementI. INTRODUCTIONIn the image formation, transfer or conversion process, due to other objective factors such as system noise, inadequate or excessive exposure, relative motion and so the impact will get the image often a difference between the original image (referred to as degraded or degraded) Degraded image is usually blurred or after the extraction of information through the machine to reduce or even wrong, it must take some measures for its improvement.Image enhancement technology is proposed in this sense, and the purpose is to improve the image quality. Fuzzy Image Enhancement situation according to the image using a variety of special technical highlights some of the information in the image, reduce or eliminate the irrelevant information, to emphasize the image of the whole or the purpose of local features. Image enhancement method is still no unified theory, image enhancement techniques can be divided into three categories: point operations, and spatial frequency enhancement methods Enhancement Act. This paper presents an automatic adjustment according to the image characteristics of adaptive image enhancement method that called hybrid genetic algorithm. It combines the differential evolution algorithm of adaptive search capabilities, automatically determines the transformation function of the parameter values in order to achieve adaptive image enhancement.…………………………………………………装………………订………………线…………………………………………………………………II. IMAGE ENHANCEMENT TECHNOLOGYImage enhancement refers to some features of the image, such as contour, contrast, emphasis or highlight edges, etc., in order to facilitate detection or further analysis and processing. Enhancements will not increase the information in the image data, but will choose the appropriate features of the expansion of dynamic range, making these features more easily detected or identified, for the detection and treatment follow-up analysis and lay a good foundation.Image enhancement method consists of point operations, spatial filtering, and frequency domain filtering categories. Point operations, including contrast stretching, histogram modeling, and limiting noise and image subtraction techniques. Spatial filter including low-pass filtering, median filtering, high pass filter (image sharpening). Frequency filter including homomorphism filtering, multi-scale multi-resolution image enhancement applied [1].III. DIFFERENTIAL EVOLUTION ALGORITHMDifferential Evolution (DE) was first proposed by Price and Storn, and with other evolutionary algorithms are compared, DE algorithm has a strong spatial search capability, and easy to implement, easy to understand. DE algorithm is a novel search algorithm, it is first in the search space randomly generates the initial population and then calculate the difference between any two members of the vector, and the difference is added to the third member of the vector, by which Method to form a new individual. If you find that the fitness of new individual members better than the original, then replace the original with the formation of individual self.The operation of DE is the same as genetic algorithm, and it conclude mutation, crossover and selection, but the methods are different. We suppose that the group size is P, the vector dimension is D, and we can express the object vector as (1):xi=[xi1，xi2，…，xiD] (i =1,…,P)(1) And the mutation vector can be expressed as (2):()321rrriXXFXV-⨯+=i=1,...,P (2) 1rX,2rX,3rX are three randomly selected individuals from group, and r1≠r2≠r3≠i.F is a range of [0, 2] between the actual type constant factor difference vector is used to control the influence, commonly referred to as scaling factor. Clearly the difference between the vector and the smaller the disturbance also smaller, which means that if groups close to the optimum value, the disturbance will be automatically reduced.DE algorithm selection operation is a "greedy " selection mode, if and only if the new vector ui the fitness of the individual than the target vector is better when the individual xi, ui will be retained to the next group. Otherwise, the target vector xi individuals remain in the original group, once again as the next generation of the parent vector.…………………………………………………装………………订………………线…………………………………………………………………IV. HYBRID GA FOR IMAGE ENHANCEMENT IMAGEenhancement is the foundation to get the fast object detection, so it is necessary to find real-time and good performance algorithm. For the practical requirements of different systems, many algorithms need to determine the parameters and artificial thresholds. Can use a non-complete Beta function, it can completely cover the typical image enhancement transform type, but to determine the Beta function parameters are still many problems to be solved. This section presents a Beta function, since according to the applicable method for image enhancement, adaptive Hybrid genetic algorithm search capabilities, automatically determines the transformation function of the parameter values in order to achieve adaptive image enhancement.The purpose of image enhancement is to improve image quality, which are more prominent features of the specified restore the degraded image details and so on. In the degraded image in a common feature is the contrast lower side usually presents bright, dim or gray concentrated. Low-contrast degraded image can be stretched to achieve a dynamic histogram enhancement, such as gray level change. We use Ixy to illustrate the gray level of point (x, y) which can be expressed by (3).Ixy=f(x, y) (3) where: “f” is a linear or nonline ar function. In general, gray image have four nonlinear translations [6] [7] that can be shown as Figure 1. We use a normalized incomplete Beta function to automatically fit the 4 categories of image enhancement transformation curve. It defines in (4):()()()()10,01,111<<-=---⎰βαβαβαdtttBufu(4) where:()()⎰---=1111,dtttBβαβα(5) For different value of α and β, we can get response curve from (4) and (5).The hybrid GA can make use of the previous section adaptive differential evolution algorithm to search for the best function to determine a value of Beta, and then each pixel grayscale values into the Beta function, the corresponding transformation of Figure 1, resulting in ideal image enhancement. The detail description is follows:Assuming the original image pixel (x, y) of the pixel gray level by the formula (4),denoted byxyi,()Ω∈yx,, here Ω is the image domain. Enhanced image is denoted by Ixy. Firstly, the image gray value normalized into [0, 1] by (6).minmaxminiiiig xyxy--=(6)where:maxi andm ini express the maximum and minimum of image gray relatively.Define the nonlinear transformation function f(u) (0≤u≤1) to transform source image…………………………………………………装………………订………………线…………………………………………………………………Finally, we use the hybrid genetic algorithm to determine the appropriate Beta function f (u) the optimal parameters αand β. Will enhance the image Gxy transformed antinormalized.V. EXPERIMENT AND ANALYSISIn the simulation, we used two different types of gray-scale images degraded; the program performed 50 times, population sizes of 30, evolved 600 times. The results show that the proposed method can very effectively enhance the different types of degraded image.Figure 2, the size of the original image a 320 × 320, it's the contrast to low, and some details of the more obscure, in particular, scarves and other details of the texture is not obvious, visual effects, poor, using the method proposed in this section, to overcome the above some of the issues and get satisfactory image results, as shown in Figure 5 (b) shows, the visual effects have been well improved. From the histogram view, the scope of the distribution of image intensity is more uniform, and the distribution of light and dark gray area is more reasonable. Hybrid genetic algorithm to automatically identify the nonlinear…………………………………………………装………………订………………线…………………………………………………………………transformation of the function curve, and the values obtained before 9.837,5.7912, from the curve can be drawn, it is consistent with Figure 3, c-class, that stretch across the middle region compression transform the region, which were consistent with the histogram, the overall original image low contrast, compression at both ends of the middle region stretching region is consistent with human visual sense, enhanced the effect of significantly improved.Figure 3, the size of the original image a 320 × 256, the overall intensity is low, the use of the method proposed in this section are the images b, we can see the ground, chairs and clothes and other details of the resolution and contrast than the original image has Improved significantly, the original image gray distribution concentrated in the lower region, and the enhanced image of the gray uniform, gray before and after transformation and nonlinear transformation of basic graph 3 (a) the same class, namely, the image Dim region stretching, and the values were 5.9409,9.5704, nonlinear transformation of images degraded type inference is correct, the enhanced visual effect and good robustness enhancement.Difficult to assess the quality of image enhancement, image is still no common evaluation criteria, common peak signal to noise ratio (PSNR) evaluation in terms of line, but the peak signal to noise ratio does not reflect the human visual system error. Therefore, we use marginal protection index and contrast increase index to evaluate the experimental results.Edgel Protection Index (EPI) is defined as follows:…………………………………………………装………………订………………线…………………………………………………………………(7)Contrast Increase Index (CII) is defined as follows:minmaxminmax,GGGGCCCEOD+-==(8)In figure 4, we compared with the Wavelet Transform based algorithm and get the evaluate number in TABLE I.Figure 4 (a, c) show the original image and the differential evolution algorithm for enhanced results can be seen from the enhanced contrast markedly improved, clearer image details, edge feature more prominent. b, c shows the wavelet-based hybrid genetic algorithm-based Comparison of Image Enhancement: wavelet-based enhancement method to enhance image detail out some of the image visual effect is an improvement over the original image, but the enhancement is not obvious; and Hybrid genetic algorithm based on adaptive transform image enhancement effect is very good, image details, texture, clarity is enhanced compared with the results based on wavelet transform has greatly improved the image of the post-analytical processing helpful. Experimental enhancement experiment using wavelet transform "sym4" wavelet, enhanced differential evolution algorithm experiment, the parameters and the values were 5.9409,9.5704. For a 256 × 256 size image transform based on adaptive hybrid genetic algorithm in Matlab 7.0 image enhancement software, the computing time is about 2 seconds, operation is very fast. From TABLE I, objective evaluation criteria can be seen, both the edge of the protection index, or to enhance the contrast index, based on adaptive hybrid genetic algorithm compared to traditional methods based on wavelet transform has a larger increase, which is from This section describes the objective advantages of the method. From above analysis, we can see…………………………………………………装………………订………………线…………………………………………………………………that this method.From above analysis, we can see that this method can be useful and effective.VI. CONCLUSIONIn this paper, to maintain the integrity of the perspective image information, the use of Hybrid genetic algorithm for image enhancement, can be seen from the experimental results, based on the Hybrid genetic algorithm for image enhancement method has obvious effect. Compared with other evolutionary algorithms, hybrid genetic algorithm outstanding performance of the algorithm, it is simple, robust and rapid convergence is almost optimal solution can be found in each run, while the hybrid genetic algorithm is only a few parameters need to be set and the same set of parameters can be used in many different problems. Using the Hybrid genetic algorithm quick search capability for a given test image adaptive mutation, search, to finalize the transformation function from the best parameter values. And the exhaustive method compared to a significant reduction in the time to ask and solve the computing complexity. Therefore, the proposed image enhancement method has some practical value.REFERENCES[1] HE Bin et al., Visual C++ Digital Image Processing [M], Posts & Telecom Press,2001,4:473～477[2] Storn R, Price K. Differential Evolution—a Simple and Efficient Adaptive Scheme forGlobal Optimization over Continuous Space[R]. International Computer Science Institute, Berlaey, 1995.[3] Tubbs J D. A note on parametric image enhancement [J].Pattern Recognition.1997,30(6):617-621.[4] TANG Ming, MA Song De, XIAO Jing. Enhancing Far Infrared Image Sequences withModel Based Adaptive Filtering [J] . CHINESE JOURNAL OF COMPUTERS, 2000, 23(8):893-896.[5] ZHOU Ji Liu, LV Hang, Image Enhancement Based on A New Genetic Algorithm [J].Chinese Journal of Computers, 2001, 24(9):959-964.[6] LI Yun, LIU Xuecheng. On Algorithm of Image Constract Enhancement Based onWavelet Transformation [J]. Computer Applications and Software, 2008,8.[7] XIE Mei-hua, WANG Zheng-ming, The Partial Differential Equation Method for ImageResolution Enhancement [J]. Journal of Remote Sensing, 2005，9(6):673-679.…………………………………………………装………………订………………线…………………………………………………………………基于混合遗传算法的图像增强技术Mu Dongzhou 徐州工业职业技术学院信息工程系 XuZhou, China****************.cnXu Chao and Ge Hongmei 徐州工业职业技术学院信息工程系 XuZhou,********************.cn,***************.cn摘要—在图像增强之中，塔布斯提出了归一化不完全β函数表示常用的几种使用的非线性变换函数对图像进行研究增强。
数字图像检测中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)Edge detection in noisy images by neuro-fuzzyprocessing通过神经模糊处理的噪声图像边缘检测AbstractA novel neuro-fuzzy (NF) operator for edge detection in digital images corrupted by impulse noise is presented. The proposed operator is constructed by combining a desired number of NF subdetectors with a postprocessor. Each NF subdetector in the structure evaluates a different pixel neighborhood relation. Hence, the number of NF subdetectors in the structure may be varied to obtain the desired edge detection performance. Internal parameters of the NF subdetectors are adaptively optimized by training by using simple artificial training images. The performance of the proposed edge detector is evaluated on different test images and compared with popular edge detectors from the literature. Simulation results indicate that the proposed NF operator outperforms competing edge detectors and offers superior performance in edge detection in digital images corrupted by impulse noise.Keywords: Neuro-fuzzy systems; Image processing; Edge detection摘要针对被脉冲信号干扰的数字图像进行边缘检测，提出了一种新型的NF边缘检测器，它是由一定数量的NF子探测器与一个后处理器组成。
外文翻译---图像的边缘检测
附：英文资料翻译图像的边缘检测To image edge examination algorithm research academic reportAbstractDigital image processing took a relative quite young discipline, is following the computer technology rapid development, day by day obtains the widespread application.The edge took the image one kind of basic characteristic, in the pattern recognition, the image division, the image intensification as well as the image compression and so on in the domain has a more widespread application.Image edge detection method many and varied, in which based on brightness algorithm, is studies the time to be most long, the theory develops the maturest method, it mainly is through some difference operator, calculates its gradient based on image brightness the change, thus examines the edge, mainly has Robert, Laplacian, Sobel, Canny, operators and so on LOG. First as a whole introduced digital image processing and the edge detection survey, has enumerated several kind of at present commonly used edge detection technology and the algorithm, and selects two kinds to use Visual the C language programming realization, through withdraws the image result to two algorithms the comparison, the research discusses their good and bad points.对图像边缘检测算法的研究学术报告摘要数字图像处理作为一门相对比较年轻的学科, 伴随着计算机技术的飞速发展, 日益得到广泛的应用. 边缘作为图像的一种基本特征, 在图像识别,图像分割,图像增强以及图像压缩等的领域中有较为广泛的应用.图像边缘提取的手段多种多样,其中基于亮度的算法,是研究时间最久,理论发展最成熟的方法, 它主要是通过一些差分算子, 由图像的亮度计算其梯度的变化, 从而检测出边缘, 主要有Robert, Laplacian, Sobel, Canny, LOG 等算子. 首先从总体上介绍了数字图像处理及边缘提取的概况, 列举了几种目前常用的边缘提取技术和算法,并选取其中两种使用Visual C++语言编程实现,通过对两种算法所提取图像结果的比较,研究探讨它们的优缺点.First chapter introduction§1.1 image edge examination introductionThe image edge is one of image most basic characteristics, often is carrying image majority of informations.But the edge exists in the image irregular structure and innot the steady phenomenon, also namely exists in the signal point of discontinuity place, these spots have given the image outline position, these outlines are frequently we when the imagery processing needs the extremely important some representative condition, this needs us to examine and to withdraw its edge to an image. But the edge examination algorithm is in the imagery processing question one of classical technical difficult problems, its solution carries on the high level regarding us the characteristic description, the recognition and the understanding and so on has the significant influence; Also because the edge examination all has in many aspects the extremely important use value, therefore how the people are devoting continuously in study and solve the structure to leave have the good nature and the good effect edge examination operator question.In the usual situation, we may the signal in singular point and the point of discontinuity thought is in the image peripheral point, its nearby gradation change situation may reflect from its neighboring picture element gradation distribution gradient. According to this characteristic, we proposed many kinds of edge examination operator: If Robert operator, Sobel operator, Prewitt operator, Laplace operator and so on.These methods many are wait for the processing picture element to carry on the gradation analysis for the central neighborhood achievement the foundation, realized and has already obtained the good processing effect to the image edge extraction. . But this kind of method simultaneously also exists has the edge picture element width, the noise jamming is serious and so on the shortcomings, even if uses some auxiliary methods to perform the denoising, also corresponding can bring the flaw which the edge fuzzy and so on overcomes with difficulty.Along with the wavelet analysis appearance, its good time frequency partial characteristic by the widespread application in the imagery processing and in the pattern recognition domain, becomes in the signal processing the commonly used method and the powerful tool.Through the wavelet analysis, may interweave decomposes in the same place each kind of composite signal the different frequency the block signal, but carries on the edge examination through the wavelet transformation, may use its multi-criteria and the multi-resolution nature fully , real effective expresses the image the edge characteristic.When the wavelet transformation criterion reduces, is more sensitive to the image detail; But when the criterion increases, the image detail is filtered out, the examination edge will be only the thick outline.This characteristic is extremely useful in the pattern recognition, we may be called this thick outline the image the main edge.If will be able an image main edge clear integrity extraction, this to the goal division, the recognition and so on following processing to bring the enormous convenience.Generally speaking, the above method all is the work which does based on the image luminance information.In the multitudinous scientific research worker under, has obtained the very good effect diligently.But, because the image edge receives physical condition and so on the illumination influences quite to be big above, often enables many to have a common shortcoming based on brightness edge detection method, that is the edge is not continual, does not seal up.Considered the phase information in the image importance as well as its stable characteristic, causes using the phase information to carry on the imagery processing into new research topic. In this paper soon introduces one kind based on the phase image characteristic examination method - - phase uniform method.It is not uses the image the luminance information, but is its phase characteristic, namely supposition image Fourier component phase most consistent spot achievement characteristic point.Not only it can examine brightness characteristics and so on step characteristic, line characteristic, moreover can examine Mach belt phenomenon which produces as a result of the human vision sensation characteristic.Because the phase uniformity does not need to carry on any supposition to the image characteristic type, therefore it has the very strong versatility.第一章绪论§1.1 图像边缘检测概论图像边缘是图像最基本的特征之一, 往往携带着一幅图像的大部分信息. 而边缘存在于图像的不规则结构和不平稳现象中,也即存在于信号的突变点处,这些点给出了图像轮廓的位置,这些轮廓常常是我们在图像处理时所需要的非常重要的一些特征条件, 这就需要我们对一幅图像检测并提取出它的边缘. 而边缘检测算法则是图像处理问题中经典技术难题之一, 它的解决对于我们进行高层次的特征描述, 识别和理解等有着重大的影响; 又由于边缘检测在许多方面都有着非常重要的使用价值, 所以人们一直在致力于研究和解决如何构造出具有良好性质及好的效果的边缘检测算子的问题.在通常情况下,我们可以将信号中的奇异点和突变点认为是图像中的边缘点,其附近灰度的变化情况可从它相邻像素灰度分布的梯度来反映. 根据这一特点,我们提出了多种边缘检测算子:如Robert 算子,Sobel算子,Prewitt 算子, Laplace 算子等.这些方法多是以待处理像素为中心的邻域作为进行灰度分析的基础,实现对图像边缘的提取并已经取得了较好的处理效果. 但这类方法同时也存在有边缘像素宽, 噪声干扰较严重等缺点,即使采用一些辅助的方法加以去噪,也相应的会带来边缘模糊等难以克服的缺陷.随着小波分析的出现, 其良好的时频局部特性被广泛的应用在图像处理和模式识别领域中, 成为信号处理中常用的手段和有力的工具. 通过小波分析, 可以将交织在一起的各种混合信号分解成不同频率的块信号,而通过小波变换进行边缘检测,可以充分利用其多尺度和多分辨率的性质,真实有效的表达图像的边缘特征.当小波变换的尺度减小时,对图像的细节更加敏感;而当尺度增大时,图像的细节将被滤掉,检测的边缘只是粗轮廓.该特性在模式识别中非常有用,我们可以将此粗轮廓称为图像的主要边缘.如果能将一个图像的主要边缘清晰完整的提取出来,这将对目标分割,识别等后续处理带来极大的便利.总的说来,以上方法都是基于图像的亮度信息来作的工作. 在众多科研工作者的努力下,取得了很好的效果.但是,由于图像边缘受到光照等物理条件的影响比较大, 往往使得以上诸多基于亮度的边缘提取方法有着一个共同的缺点, 那就是边缘不连续, 不封闭. 考虑到相位信息在图像中的重要性以及其稳定的特点, 使得利用相位信息进行图像处理成为新的研究课题. 在本文中即将介绍一种基于相位的图像特征检测方法——相位一致性方法. 它并不是利用图像的亮度信息,而是其相位特点,即假设图像的傅立叶分量相位最一致的点作为特征点.它不但能检测到阶跃特征, 线特征等亮度特征, 而且能够检测到由于人类视觉感知特性而产生的的马赫带现象. 由于相位一致性不需要对图像的特征类型进行任何假设,所以它具有很强的通用性.§1.2 image edge definitionThe image majority main information all exists in the image edge, the main performance for the image partial characteristic discontinuity, is in the image the gradation change quite fierce place, also is the signal which we usually said has the strange change place. The strange signal the gradation change which moves towards along the edge is fierce, usually we divide the edge for the step shape and the roof shape two kind of types (as shown in Figure 1-1).In the step edge two side grey levels have the obvious change; But the roof shape edge is located the gradation increase and the reduced intersection point.May portray the peripheral point in mathematics using the gradation derivative the change, to the step edge, the roof shape edge asks its step, the second time derivative separately. To an edge, has the possibility simultaneously to have the step and the line edge characteristic. For example on a surface, changes from a plane to the normal direction different another plane can produce the step edge; If this surface has the edges and corners which the regular reflection characteristic also two planes form quite to be smooth, then works as when edges and corners smooth surface normal after mirror surface reflection angle, as a result of the regular reflection component, can produce the bright light strip on the edges and corners smooth surface, such edge looked like has likely superimposed a line edge in the step edge. Because edge possible and in scene object important characteristic correspondence, therefore it is the very important image characteristic.Forinstance, an object outline usually produces the step edge, because the object image intensity is different with the background image intensity.§1.3 paper selected topic theory significanceThe paper selected topic originates in holds the important status and the function practical application topic in the image project.The so-called image project discipline is refers foundation discipline and so on mathematics, optics principles, the discipline which in the image application unifies which accumulates the technical background develops.The image project content is extremely rich, and so on divides into three levels differently according to the abstract degree and the research technique: Imagery processing, image analysis and image understanding.As shown in Figure 1-2, in the chart the image division is in between the image analysis and the imagery processing, its meaning is, the image division is from the imagery processing to the image analysis essential step, also is further understands the image the foundation. The image division has the important influence to the characteristic.The image division and based on thedivision goal expression, the characteristic extraction and the parameter survey and so on transforms the primitive image as a more abstract more compact form, causes the high-level image analysis and possibly understands into.But the edge examination is the image division core content, therefore the edge examination holds the important status and the function in the image project.Therefore the edge examination research always is in the image engineering research the hot spot and the focal point, moreover the people enhance unceasingly to its attention and the investment.§1.2 图像边缘的定义图像的大部分主要信息都存在于图像的边缘中, 主要表现为图像局部特征的不连续性, 是图像中灰度变化比较剧烈的地方, 也即我们通常所说的信号发生奇异变化的地方. 奇异信号沿边缘走向的灰度变化剧烈,通常我们将边缘划分为阶跃状和屋顶状两种类型(如图1-1 所示).阶跃边缘中两边的灰度值有明显的变化; 而屋顶状边缘位于灰度增加与减少的交界处. 在数学上可利用灰度的导数来刻画边缘点的变化,对阶跃边缘,屋顶状边缘分别求其一阶,二阶导数. 对一个边缘来说,有可能同时具有阶跃和线条边缘特性.例如在一个表面上,由一个平面变化到法线方向不同的另一个平面就会产生阶跃边缘; 如果这一表面具有镜面反射特性且两平面形成的棱角比较圆滑,则当棱角圆滑表面的法线经过镜面反射角时,由于镜面反射分量,在棱角圆滑表面上会产生明亮光条, 这样的边缘看起来象在阶跃边缘上叠加了一个线条边缘. 由于边缘可能与场景中物体的重要特征对应,所以它是很重要的图像特征.比如,一个物体的轮廓通常产生阶跃边缘, 因为物体的图像强度不同于背景的图像强度.§1.3 论文选题的理论意义论文选题来源于在图像工程中占有重要的地位和作用的实际应用课题.所谓图像工程学科是指将数学,光学等基础学科的原理,结合在图像应用中积累的技术经验而发展起来的学科.图像工程的内容非常丰富,根据抽象程度和研究方法等的不同分为三个层次:图像处理,图像分析和图像理解.如图1-2 所示,在图中,图像分割处于图像分析与图像处理之间,其含义是,图像分割是从图像处理进到图像分析的关键步骤,也是进一步理解图像的基础.图像分割对特征有重要影响. 图像分割及基于分割的目标表达, 特征提取和参数测量等将原始图像转化为更抽象更紧凑的形式, 使得更高层的图像分析和理解成为可能. 而边缘检测是图像分割的核心内容, 所以边缘检测在图像工程中占有重要的地位和作用. 因此边缘检测的研究一直是图像技术研究中热点和焦点,而且人们对其的关注和投入不断提高.。
外文翻译---MATLAB 在图像边缘检测中的应用
英文资料翻译MATLAB application in image edge detection MATLAB of the 1984 countries MathWorks company to market since, after 10 years of development, has become internationally recognized the best technology application software. MATLAB is not only a kind of direct, efficient computer language, and at the same time, a scientific computing platform, it for data analysis and data visualization, algorithm and application development to provide the most core of math and advanced graphics tools. According to provide it with the more than 500 math and engineering function, engineering and technical personnel and scientific workers can integrated environment of developing or programming to complete their calculation.MATLAB software has very strong openness and adapt to sex. Keep the kernel in under the condition of invariable, MATLAB is in view of the different application subject of launch corresponding Toolbox (Toolbox), has now launched image processing Toolbox, signal processing Toolbox, wavelet Toolbox, neural network Toolbox and communication tools box, etc multiple disciplines special kit, which would place of different subjects research work.MATLAB image processing kit is by a series of support image processing function from the composition, the support of the image processing operation: geometric operation area of operation and operation; Linear filter and filter design; Transform (DCT transform); Image analysis and strengthened; Binary image manipulation, etc. Image processing tool kit function, the function can be divided into the following categories: image display; Image file input and output; Geometric operation; Pixels statistics; Image analysis and strengthened; Image filtering; Sex 2 d filter design; Image transformation; Fields and piece of operation; Binary image operation; Color mapping and color space transformation; Image types and type conversion; Kit acquiring parameters and Settings.1.Edge detection thisUse computer image processing has two purposes: produce more suitable for human observation and identification of the images; Hope can by the automatic computer image recognition and understanding.No matter what kind of purpose to, image processing the key step is to contain a variety of scenery of decomposition of image information. Decomposition of the end result is that break down into some has some kind of characteristics of the smallest components, known as the image of the yuan. Relative to the whole image of speaking, this the yuan more easily to be rapid processing.Image characteristics is to point to the image can be used as the sign of the field properties, it can be divided into the statistical features of the image and image visual, two types of levy. The statistical features of the image is to point to some people the characteristics of definition, through the transform to get, such as image histogram, moments, spectrum, etc.; Image visual characteristics is refers to person visual sense can be directly by the natural features, such as the brightness of the area, and texture or outline, etc. The two kinds of characteristics of the image into a series of meaningful goal or regional p rocess called image segmentation.The image is the basic characteristics of edge, the edge is to show its pixel grayscale around a step change order or roof of the collection of those changes pixels. It exists in target and background, goals and objectives, regional and region, the yuan and the yuan between, therefore, it is the image segmentation dependent on the most important characteristic that the texture characteristics of important information sources and shape characteristics of the foundation, and the image of the texture characteristics and the extraction of shape often dependent on image segmentation. Image edge extraction is also the basis of image matching, because it is the sign of position, the change of the original is not sensitive, and can be used for matching the feature points.The edge of the image is reflected by gray not continuity. Classic edge extraction method is investigation of each pixel image in an area of the gray change, use edge first or second order nearby directional derivative change rule,with simple method of edge detection, this method called edge detection method of local operators.The type of edge can be divided into two types: (1) step representation sexual edge, it on both sides of the pixel gray value varies significantly different; (2) the roof edges, it is located in gray value from the change of increased to reduce the turning point. For order jump sexual edge, second order directional derivative in edge is zero cross; For the roof edges, second order directional derivative in edge take extreme value.If a pixel fell in the image a certain object boundary, then its field will become a gray level with the change. The most useful to change two features is the rate of change and the gray direction, they are in the range of the gradient vector and the direction to said. Edge detection operator check every pixel grayscale rate fields and evaluation, and also include to determine the directions of the most use based on directional derivative deconvolution method for masking.Digital image processing technique has been widely applied to the biomedical field, the use of computer image processing and analysis, and complete detection and recognition of cancer cells can help doctors make a diagnosis of tumor cancers. Need to be made in the identification of cancer cells, the quantitative results, the human eye is difficult to accurately complete such work, and the use of computer image processing to complete the analysis and identification of the microscopic images have made great progress. In recent years, domestic and foreign medical images of cancer cells testing to identify the researchers put forward a lot of theory and method for the diagnosis of cancer cells has very important meaning and practical value.Cell edge detection is the cell area of the number of roundness and color, shape and chromaticity calculation and the basis of the analysis their test results directly affect the analysis and diagnosis of the disease. Classical edge detection operators such as Sobel operator, Laplacian operator, each pixel neighborhood of the image gray scale changes to detect the edge. Although these operators is simple, fast, but there are sensitive to noise, get isolated or in short sections of acontinuous edge pixels, overlapping the adjacent cell edge defects, while the optimal threshold segmentation and contour extraction method of combining edge detection, obtained by the iterative algorithm for the optimal threshold for image segmentation, contour extraction algorithm, digging inside the cell pixels, the last remaining part of the image is the edge of the cell, change the processing order of the traditional edge detection algorithm, by MATLAB programming, the experimental results that can effectively suppress the noise impact at the same time be able to objectively and correctly select the edge detection threshold, precision cell edge detection.2.Edge detection of MATLABMATLAB image processing toolkit defines the edge () function is used to test the edge of gray image.(1) BW = edge (I, "method"), returns and I size binary image BW, includingelements of 1 said is on the edge of the point, 0 means the edge points.Method for the following a string of:1) soble: the default value, with derivative Sobel edge detectionapproximate measure, to return to a maximum gradient edge;2) prewitt: with the derivative prewitt approximate edge detection, amaximum gradient to return to edge;3) Roberts: with the derivative Roberts approximate edge detection margins,return to a maximum gradient edge;4) the log: use the Laplace operation gaussian filter to I carry filtering,through the looking for 0 intersecting detection of edge;5) zerocross: use the filter to designated I filter, looking for 0 intersectingdetection of edge.(2) BW = edge (I, "method", thresh) with thresh designated sensitivitythreshold value, rather than the edge of all not thresh are ignored.(3) BW = edge (I, "method" thresh, direction, for soble and prewitt methodspecified direction, direction for string, including horizontal level said direction; Vertical said to hang straight party; Both said the two directions(the default).(4) BW = edge (I, 'log', thresh, log sigma), with sigma specified standarddeviation.(5) [BW, thresh] = edge (...), the return value of a function in fact have multiple(" BW "and" thresh "), but because the brace up with u said as a matrix, and so can be thought a return only parameters, which also shows the introduction of the concept of matrix MATLAB unity and superiority.st wordMATLAB has strong image processing function, provide a simple function calls to realize many classic image processing method. Not only is the image edge detection, in transform domain processing, image enhancement, mathematics morphological processing, and other aspects of the study, MATLAB can greatly improve the efficiency rapidly in the study of new ideas.MATLAB 在图像边缘检测中的应用MATLAB自1984年由国MathWorks公司推向市场以来,历经十几年的发展,现已成为国际公认的最优秀的科技应用软件。
数字图像处理__Canny边缘检测
摘要边缘检测是数字图像处理中的重要内容，边缘是图像最基本的特性。
在图像边缘检测中，微分算子可以提取出图像的细节信息，景物边缘是细节信息中最具有描述景物特征的部分,也是图像分析中的一个不可或缺的部分。
本文详细地分析了目前常用的几种算法，即：Roberts交叉微分算子、Sobel微分算子、Priwitt微分算子和Laplacian微分算子以及Canny算子，用C语言编程实现各算子的边缘检测，并根据边缘检测的有效性和定位的可靠性，得出Canny算子具备有最优边缘检测所需的特性。
关键词：图像处理，微分算子，Canny算子，边缘检测AbstractEdge detection is the important contents of digital image processing ,and the edge is the most basic characteristics of the image.In the image edge detection ,differential operator can be used to extract the details of the images,features’edge is the most detailed information describing the characteristics of the features of the image analysis, and is also an integral part of the image.This article gives the detailed analysis of several algorithms which is commonly used at present,such as Roberts cross-differential operator、Sobel differential operator、Priwitt differential operator、Laplacian differential operator and Canny operator,and we complete with the C language procedure to come ture edge detection.According to the effectiveness of the image detection and the reliability of the orientation,we can deduced that the Canny operator have the characteristics which the image edge has.Keywords: Image processing, Canny operator, differential operator, edge detection目录摘要 (I)Abstract (II)第一章绪论 (1)1.1 引言 (1)1.2 数字图像技术的概述 (2)1.3 边缘检测 (3)1.4 论文各章节的安排 (4)第二章微分算子边缘检测 (5)2.1 Roberts算子 (5)2.2 Sobel算子 (5)2.3 Priwitt算子 (6)2.4 Laplacian算子 (6)第三章Canny边缘检测 (8)3.1 Canny指标 (8)3.2 Canny算子的实现 (9)第四章程序设计与实验 (12)4.1各微分算子的程序设计 (12)4.2 实验结果及比较 (14)第五章结论与展望 (17)5.1 结论 (17)5.2 展望 (17)致谢 ..................................................................................................... 错误！未定义书签。
数字图像处理外文翻译参考文献
数字图像处理外文翻译参考文献(文档含中英文对照即英文原文和中文翻译)原文：Application Of Digital Image Processing In The MeasurementOf Casting Surface RoughnessAhstract- This paper presents a surface image acquisition system based on digital image processing technology. The image acquired by CCD is pre-processed through the procedure of image editing, image equalization, the image binary conversation and feature parameters extraction to achieve casting surface roughness measurement. The three-dimensional evaluation method is taken to obtain the evaluation parametersand the casting surface roughness based on feature parameters extraction. An automatic detection interface of casting surface roughness based on MA TLAB is compiled which can provide a solid foundation for the online and fast detection of casting surface roughness based on image processing technology.Keywords-casting surface; roughness measurement; image processing; feature parametersⅠ.INTRODUCTIONNowadays the demand for the quality and surface roughness of machining is highly increased, and the machine vision inspection based on image processing has become one of the hotspot of measuring technology in mechanical industry due to their advantages such as non-contact, fast speed, suitable precision, strong ability of anti-interference, etc [1,2]. As there is no laws about the casting surface and the range of roughness is wide, detection parameters just related to highly direction can not meet the current requirements of the development of the photoelectric technology, horizontal spacing or roughness also requires a quantitative representation. Therefore, the three-dimensional evaluation system of the casting surface roughness is established as the goal [3,4], surface roughness measurement based on image processing technology is presented. Image preprocessing is deduced through the image enhancement processing, the image binary conversation. The three-dimensional roughness evaluation based on the feature parameters is performed . An automatic detection interface of casting surface roughness based on MA TLAB is compiled which provides a solid foundation for the online and fast detection of casting surface roughness.II. CASTING SURFACE IMAGE ACQUISITION SYSTEMThe acquisition system is composed of the sample carrier, microscope, CCD camera, image acquisition card and the computer. Sample carrier is used to place tested castings. According to the experimental requirements, we can select a fixed carrier and the sample location can be manually transformed, or select curing specimens and the position of the sampling stage can be changed. Figure 1 shows the whole processing procedure.,Firstly,the detected castings should be placed in the illuminated backgrounds as far as possible, and then through regulating optical lens, setting the CCD camera resolution and exposure time, the pictures collected by CCD are saved to computer memory through the acquisition card. The image preprocessing and feature value extraction on casting surface based on corresponding software are followed. Finally the detecting result is output.III. CASTING SURFACE IMAGE PROCESSINGCasting surface image processing includes image editing, equalization processing, image enhancement and the image binary conversation,etc. The original and clipped images of the measured casting is given in Figure 2. In which a) presents the original image and b) shows the clipped image.A.Image EnhancementImage enhancement is a kind of processing method which can highlight certain image information according to some specific needs and weaken or remove some unwanted informations at the same time[5].In order to obtain more clearly contour of the casting surface equalization processing of the image namely the correction of the image histogram should be pre-processed before image segmentation processing. Figure 3 shows the original grayscale image and equalization processing image and their histograms. As shown in the figure, each gray level of the histogram has substantially the same pixel point and becomes more flat after gray equalization processing. The image appears more clearly after the correction and the contrast of the image is enhanced.Fig.2 Casting surface imageFig.3 Equalization processing imageB. Image SegmentationImage segmentation is the process of pixel classification in essence. It is a very important technology by threshold classification. The optimal threshold is attained through the instmction thresh = graythresh (II). Figure 4 shows the image of the binary conversation. The gray value of the black areas of the Image displays the portion of the contour less than the threshold (0.43137), while the white area shows the gray value greater than the threshold. The shadows and shading emerge in the bright region may be caused by noise or surface depression.Fig4 Binary conversationIV. ROUGHNESS PARAMETER EXTRACTIONIn order to detect the surface roughness, it is necessary to extract feature parameters of roughness. The average histogram and variance are parameters used to characterize the texture size of surface contour. While unit surface's peak area is parameter that can reflect the roughness of horizontal workpiece.And kurtosis parameter can both characterize the roughness of vertical direction and horizontal direction. Therefore, this paper establisheshistogram of the mean and variance, the unit surface's peak area and the steepness as the roughness evaluating parameters of the castings 3D assessment. Image preprocessing and feature extraction interface is compiled based on MATLAB. Figure 5 shows the detection interface of surface roughness. Image preprocessing of the clipped casting can be successfully achieved by this software, which includes image filtering, image enhancement, image segmentation and histogram equalization, and it can also display the extracted evaluation parameters of surface roughness.Fig.5 Automatic roughness measurement interfaceV. CONCLUSIONSThis paper investigates the casting surface roughness measuring method based on digital Image processing technology. The method is composed of image acquisition, image enhancement, the image binary conversation and the extraction of characteristic parameters of roughness casting surface. The interface of image preprocessing and the extraction of roughness evaluation parameters is compiled by MA TLAB which can provide a solid foundation for the online and fast detection of casting surface roughness.REFERENCE[1] Xu Deyan, Lin Zunqi. The optical surface roughness research pro gress and direction[1]. Optical instruments 1996, 18 (1): 32-37.[2] Wang Yujing. Turning surface roughness based on image measurement [D]. Harbin:Harbin University of Science and Technology[3] BRADLEY C. Automated surface roughness measurement[1]. The InternationalJournal of Advanced Manufacturing Technology ,2000,16(9) :668-674.[4] Li Chenggui, Li xing-shan, Qiang XI-FU 3D surface topography measurement method[J]. Aerospace measurement technology, 2000, 20(4): 2-10.[5] Liu He. Digital image processing and application [ M]. China Electric Power Press,2005译文：数字图像处理在铸件表面粗糙度测量中的应用摘要—本文提出了一种表面图像采集基于数字图像处理技术的系统。
外文文献附翻译---数字图像处理与边缘检测
Digital Image Processing and Edge DetectionDigital Image ProcessingInterest in digital image processing methods stems from two principal applica- tion areas: improvement of pictorial information for human interpretation; and processing of image data for storage, transmission, and representation for au- tonomous machine perception.An image may be defined as a two-dimensional function, f(x, y), where x and y are spatial (plane) coordinates, and the amplitude of f at any pair of coordinates (x, y) is called the intensity or gray level of the image at that point. When x, y, and the amplitude values of f are all finite, discrete quantities, we call the image a digital image. The field of digital image processing refers to processing digital images by means of a digital computer. Note that a digital image is composed of a finite number of elements, each of which has a particular location and value. These elements are referred to as picture elements, image elements, pels, and pixels. Pixel is the term most widely used to denote the elements of a digital image.Vision is the most advanced of our senses, so it is not surprising that images play the single most important role in human perception. However, unlike humans, who are limited to the visual band of the electromagnetic (EM) spec- trum, imaging machines cover almost the entire EM spectrum, ranging from gamma to radio waves. They can operate on images generated by sources that humans are not accustomed to associating with images. These include ultra- sound, electron microscopy, and computer-generated images. Thus, digital image processing encompasses a wide and varied field of applications.There is no general agreement among authors regarding where image processing stops and other related areas, such as image analysis and computer vi- sion, start. Sometimes a distinction is made by defining image processing as a discipline in which both the input and output of a process are images. We believe this to be a limiting and somewhat artificial boundary. For example, under this definition, even the trivial task of computing the average intensity of an image (which yields a single number) would not be considered an image processing operation. On the other hand, there are fields such as computer vision whose ultimate goal is to use computers to emulate human vision, including learning and being able to make inferences and take actions based on visual inputs. This area itself is a branch of artificial intelligence (AI) whose objective is to emulate human intelligence. The field of AI is in its earliest stages of infancy in terms of development, with progress having been much slower than originally anticipated. The area of image analysis (also called image understanding) is in be- tween image processing and computer vision.There are no clearcut boundaries in the continuum from image processing at one end to computer vision at the other. However, one useful paradigm is to consider three types of computerized processes in this continuum: low-, mid-, and highlevel processes. Low-level processes involve primitive opera- tions such as image preprocessing to reduce noise, contrast enhancement, and image sharpening. Alow-level process is characterized by the fact that both its inputs and outputs are images. Mid-level processing on images involves tasks such as segmentation (partitioning an image into regions or objects), description of those objects to reduce them to a form suitable for computer processing, and classification (recognition) of individual objects. A midlevel process is characterized by the fact that its inputs generally are images, but its outputs are attributes extracted from those images (e.g., edges, contours, and the identity of individual objects). Finally, higherlevel processing involves “making sense” of an ensemble of recognized objects, as in image analysis, and, at the far end of the continuum, performing the cognitive functions normally associated with vision.Based on the preceding comments, we see that a logical place of overlap between image processing and image analysis is the area of recognition of individual regions or objects in an image. Thus, what we call in this book digital image processing encompasses processes whose inputs and outputs are images and, in addition, encompasses processes that extract attributes from images, up to and including the recognition of individual objects. As a simple illustration to clarify these concepts, consider the area of automated analysis of text. The processes of acquiring an image of the area containing the text, preprocessing that image, extracting (segmenting) the individual characters, describing the characters in a form suitable for computer processing, and recognizing those individual characters are in the scope of what we call digital image processing in this book. Making sense of the content of the page may be viewed as being in the domain of image analysis and even computer vision, depending on the level of complexity implied by the statement “making sense.” As will become evident shortly, digital image processing, as we have defined it, is used successfully in a broad range of areas of exceptional social and economic value.The areas of application of digital image processing are so varied that some form of organization is desirable in attempting to capture the breadth of this field. One of the simplest ways to develop a basic understanding of the extent of image processing applications is to categorize images according to their source (e.g., visual, X-ray, and so on). The principal energy source for images in use today is the electromagnetic energy spectrum. Other important sources of energy include acoustic, ultrasonic, and electronic (in the form of electron beams used in electron microscopy). Synthetic images, used for modeling and visualization, are generated by computer. In this section we discuss briefly how images are generated in these various categories and the areas in which they are applied.Images based on radiation from the EM spectrum are the most familiar, es- pecially images in the X-ray and visual bands of the spectrum. Electromagnet- ic waves can be conceptualized as propagating sinusoidal waves of varying wavelengths, or they can be thought of as a stream of massless particles, each traveling in a wavelike pattern and moving at the speed of light. Each massless particle contains a certain amount (or bundle) of energy. Each bundle of energy is called a photon. If spectral bands are grouped according to energy per photon, we obtain the spectrum shown in fig. below, ranging from gamma rays (highest energy) at one end to radio waves (lowestenergy) at the other. The bands are shown shaded to convey the fact that bands of the EM spectrum are not distinct but rather transition smoothly from one to the other.Image acquisition is the first process. Note that acquisition could be as simple as being given an image that is already in digital form. Generally, the image acquisition stage involves preprocessing, such as scaling.Image enhancement is among the simplest and most appealing areas of digital image processing. Basically, the idea behind enhancement techniques is to bring out detail that is obscured, or simply to highlight certain features of interest in an image. A familiar example of enhancement is when we increase the contr ast of an image because “it looks better.” It is important to keep in mind that enhancement is a very subjective area of image processing. Image restoration is an area that also deals with improving the appearance of an image. However, unlike enhancement, which is subjective, image restoration is objective, in the sense that restoration techniques tend to be based on mathematical or probabilistic models of image degradation. Enhancement, on the other hand, is based on human subjective preferences regarding what constitutes a “good” enhancement result.Color image processing is an area that has been gaining in importance because of the significant increase in the use of digital images over the Internet. It covers a number of fundamental concepts in color models and basic color processing in a digital domain. Color is used also in later chapters as the basis for extracting features of interest in an image.Wavelets are the foundation for representing images in various degrees of resolution. In particular, this material is used in this book for image data compression and for pyramidal representation, in which images are subdivided successively into smaller regions.Compression, as the name implies, deals with techniques for reducing the storage required to save an image, or the bandwidth required to transmi it.Although storage technology has improved significantly over the past decade, the same cannot be said for transmission capacity. This is true particularly in uses of the Internet, which are characterized by significant pictorial content. Image compression is familiar (perhaps inadvertently) to most users of computers in the form of image file extensions, such as the jpg file extension used in the JPEG (Joint Photographic Experts Group) image compression standard.Morphological processing deals with tools for extracting image components that are useful in the representation and description of shape. The material in this chapter begins a transition from processes that output images to processes that output image attributes.Segmentation procedures partition an image into its constituent parts or objects. In general, autonomous segmentation is one of the most difficult tasks in digital image processing. A rugged segmentation procedure brings the process a long way toward successful solution of imaging problems that require objects to be identified individually. On the other hand, weak or erratic segmentation algorithms almost always guarantee eventual failure. In general, the more accurate the segmentation, the more likely recognition is to succeed.Representation and description almost always follow the output of a segmentation stage, which usually is raw pixel data, constituting either the bound- aryof a region (i.e., the set of pixels separating one image region from another) or all the pointsin the region itself. In either case, converting the data to a form suitable for computer processing is necessary. The first decision that must be made is whether the data should be represented as a boundary or as a complete region. Boundary representation is appropriate when the focus is on external shape characteristics, such as corners and inflections. Regional representation is appropriate when the focus is on internal properties, such as texture or skeletal shape. In some applications, these representations complement each other. Choosing a representation is only part of the solution for trans- forming raw data into a form suitable for subsequent computer processing. A method must also be specified for describing the data so that features of interest are highlighted. Description, also called feature selection, deals with extracting attributes that result in some quantitative information of interest or are basic for differentiating one class of objects from another.Recognition is the process that assigns a label (e.g., “vehicle”) to an object based on its descriptors. As detailed before, we conclude our coverage of digital image processing with the development of methods for recognition of individual objects.So far we have said nothing about the need for prior knowledge or about the interaction between the knowledge base and the processing modules in Fig2 above. Knowledge about a problem domain is coded into an image processing system in the form of a knowledge database. This knowledge may be as sim- ple as detailing regions of an image where the information of interest is known to be located, thus limiting the search that has to be conducted in seeking that information. The knowledge base also can be quite complex, such as an interrelated list of all major possible defects in a materials inspection problem or an image database containing high-resolution satellite images of a region in con- nection with change-detection applications. In addition to guiding the operation of each processing module, the knowledge base also controls the interaction between modules. This distinction is made in Fig2 above by the use of double-headed arrows between the processing modules and the knowledge base, as op- posed to single-headed arrows linking the processing modules.Edge detectionEdge detection is a terminology in image processing and computer vision, particularly in the areas of feature detection and feature extraction, to refer to algorithms which aim at identifying points in a digital image at which the image brightness changes sharply or more formally has discontinuities.Although point and line detection certainly are important in any discussion on segmentation,edge dectection is by far the most common approach for detecting meaningful discounties in gray level.Although certain literature has considered the detection of ideal step edges, the edges obtained from natural images are usually not at all ideal step edges. Instead they are normally affected by one or several of the following effects:1.focal blur caused by a finite depth-of-field and finite point spread function; 2.penumbral blur caused by shadows created by light sources of non-zero radius; 3.shading at a smooth object edge; 4.local specularities or interreflections in the vicinity of object edges.A typical edge might for instance be the border between a block of red color and a blockof yellow. In contrast a line (as can be extracted by a ridge detector) can be a small number of pixels of a different color on an otherwise unchanging background. For a line, there may therefore usually be one edge on each side of the line.To illustrate why edge detection is not a trivial task, let us consider the problem of detecting edges in the following one-dimensional signal. Here, we may intuitively say thatIf if the intensity differences between the adjacent neighbouring pixels were higher, it would not be as easy to say that there should be an edge in the corresponding region. Moreover, one could argue that this case is one in which there are several edges.Hence, to firmly state a specific threshold on how large the intensity change between two neighbouring pixels must be for us to say that there should be an edge between these pixels is not always a simple problem. Indeed, this is one of the reasons why edge detection may be a non-trivial problem unless the objects in the scene are particularly simple and the illumination conditions can be well controlled.There are many methods for edge detection, but most of them can be grouped into two categories,search-based and zero-crossing based. The search-based methods detect edges by first computing a measure of edge strength, usually a first-order derivative expression such as the gradient magnitude, and then searching for local directional maxima of the gradient magnitude using a computed estimate of the local orientation of the edge, usually the gradient direction. The zero-crossing based methods search for zero crossings in a second-order derivative expression computed from the image in order to find edges, usually the zero-crossings of the Laplacian or the zero-crossings of a non-linear differential expression, as will be described in the section on differential edge detection following below. As a pre-processing step to edge detection, a smoothing stage, typically Gaussian smoothing, is almost always applied (see also noise reduction).The edge detection methods that have been published mainly differ in the types of smoothing filters that are applied and the way the measures of edge strength are computed. As many edge detection methods rely on the computation of image gradients, they also differ in the types of filters used for computing gradient estimates in the x- and y-directions.Once we have computed a measure of edge strength (typically the gradient magnitude), the next stage is to apply a threshold, to decide whether edges are present or not at an image point. The lower the threshold, the more edges will be detected, and the result will be increasingly susceptible to noise, and also to picking out irrelevant features from the image. Conversely a high threshold may miss subtle edges, or result in fragmented edges.If the edge thresholding is applied to just the gradient magnitude image, the resulting edges will in general be thick and some type of edge thinning post-processing is necessary. For edges detected with non-maximum suppression however, the edge curves are thin by definition and the edge pixels can be linked into edge polygon by an edge linking (edge tracking) procedure. On a discrete grid, the non-maximum suppression stage can be implemented by estimating the gradient direction using first-order derivatives, then rounding off the gradient direction to multiples of 45 degrees, and finally comparing the values of thegradient magnitude in the estimated gradient direction.A commonly used approach to handle the problem of appropriate thresholds for thresholding is by using thresholding with hysteresis. This method uses multiple thresholds to find edges. We begin by using the upper threshold to find the start of an edge. Once we have a start point, we then trace the path of the edge through the image pixel by pixel, marking an edge whenever we are above the lower threshold. We stop marking our edge only when the value falls below our lower threshold. This approach makes the assumption that edges are likely to be in continuous curves, and allows us to follow a faint section of an edge we have previously seen, without meaning that every noisy pixel in the image is marked down as an edge. Still, however, we have the problem of choosing appropriate thresholding parameters, and suitable thresholding values may vary over the image.Some edge-detection operators are instead based upon second-order derivatives of the intensity. This essentially captures the rate of change in the intensity gradient. Thus, in the ideal continuous case, detection of zero-crossings in the second derivative captures local maxima in the gradient.We can come to a conclusion that,to be classified as a meaningful edge point,the transition in gray level associated with that point has to be significantly stronger than the background at that point.Since we are dealing with local computations,the method of choice to determine whether a value is “significant” or not id to use a threshold.Thus we define a point in an image as being as being an edge point if its two-dimensional first-order derivative is greater than a specified criterion of connectedness is by definition an edge.The term edge segment generally is used if the edge is short in relation to the dimensions of the image.A key problem in segmentation is to assemble edge segments into longer edges.An alternate definition if we elect to use the second-derivative is simply to define the edge ponits in an image as the zero crossings of its second derivative.The definition of an edge in this case is the same as above.It is important to note that these definitions do not guarantee success in finding edge in an image.They simply give us a formalism to look for them.First-order derivatives in an image are computed using the gradient.Second-order derivatives are obtained using the Laplacian.数字图像处理与边缘检测数字图像处理数字图像处理方法的研究源于两个主要应用领域：其一是为了便于人们分析而对图像信息进行改进：其二是为使机器自动理解而对图像数据进行存储、传输及显示。
外文翻译----数字图像处理和模式识别技术关于检测癌症的应用
引言英文文献原文Digital image processing and pattern recognition techniques for the detection of cancerCancer is the second leading cause of death for both men and women in the world , and is expected to become the leading cause of death in the next few decades . In recent years , cancer detection has become a significant area of research activities in the image processing and pattern recognition community .Medical imaging technologies have already made a great impact on our capabilities of detecting cancer early and diagnosing the disease more accurately . In order to further improve the efficiency and veracity of diagnoses and treatment , image processing and pattern recognition techniques have been widely applied to analysis and recognition of cancer , evaluation of the effectiveness of treatment , and prediction of the development of cancer . The aim of this special issue is to bring together researchers working on image processing and pattern recognition techniques for the detection and assessment of cancer , and to promote research in image processing and pattern recognition for oncology . A number of papers were submitted to this special issue and each was peer-reviewed by at least three experts in the field . From these submitted papers , 17were finally selected for inclusion in this special issue . These selected papers cover a broad range of topics that are representative of the state-of-the-art in computer-aided detection or diagnosis(CAD)of cancer . They cover several imaging modalities(such as CT , MRI , and mammography) and different types of cancer (including breast cancer , skin cancer , etc.) , which we summarize below .Skin cancer is the most prevalent among all types of cancers . Three papers in this special issue deal with skin cancer . Y uan et al. propose a skin lesion segmentation method. The method is based on region fusion and narrow-band energy graph partitioning . The method can deal with challenging situations with skin lesions , such as topological changes , weak or false edges , and asymmetry . T ang proposes a snake-based approach using multi-direction gradient vector flow (GVF) for the segmentation of skin cancer images . A new anisotropic diffusion filter is developed as a preprocessing step . After the noise is removed , the image is segmented using a GVF1snake . The proposed method is robust to noise and can correctly trace the boundary of the skin cancer even if there are other objects near the skin cancer region . Serrano et al. present a method based on Markov random fields (MRF) to detect different patterns in dermoscopic images . Different from previous approaches on automatic dermatological image classification with the ABCD rule (Asymmetry , Border irregularity , Color variegation , and Diameter greater than 6mm or growing) , this paper follows a new trend to look for specific patterns in lesions which could lead physicians to a clinical assessment.Breast cancer is the most frequently diagnosed cancer other than skin cancer and a leading cause of cancer deaths in women in developed countries . In recent years , CAD schemes have been developed as a potentially efficacious solution to improving radiologists’diagnostic accuracy in breast cancer screening and diagnosis . The predominant approach of CAD in breast cancer and medical imaging in general is to use automated image analysis to serve as a “second reader”, with the aim of improving radiologists’diagnostic performance . Thanks to intense research and development efforts , CAD schemes have now been introduces in screening mammography , and clinical studies have shown that such schemes can result in higher sensitivity at the cost of a small increase in recall rate . In this issue , we have three papers in the area of CAD for breast cancer . Wei et al. propose an image-retrieval based approach to CAD , in which retrieved images similar to that being evaluated (called the query image) are used to support a CAD classifier , yielding an improved measure of malignancy . This involves searching a large database for the images that are most similar to the query image , based on features that are automatically extracted from the images . Dominguez et al. investigate the use of image features characterizing the boundary contours of mass lesions in mammograms for classification of benign vs. Malignant masses . They study and evaluate the impact of these features on diagnostic accuracy with several different classifier designs when the lesion contours are extracted using two different automatic segmentation techniques . Schaefer et al. study the use of thermal imaging for breast cancer detection . In their scheme , statistical features are extracted from thermograms to quantify bilateral differences between left and right breast regions , which are used subsequently as input to a fuzzy-rule-based classification system for diagnosis.Colon cancer is the third most common cancer in men and women , and also the third mostcommon cause of cancer-related death in the USA . Y ao et al. propose a novel technique to detect colonic polyps using CT Colonography . They use ideas from geographic information systems to employ topographical height maps , which mimic the procedure used by radiologists for the detection of polyps . The technique can also be used to measure consistently the size of polyps . Hafner et al. present a technique to classify and assess colonic polyps , which are precursors of colorectal cancer . The classification is performed based on the pit-pattern in zoom-endoscopy images . They propose a novel color waveler cross co-occurence matrix which employs the wavelet transform to extract texture features from color channels.Lung cancer occurs most commonly between the ages of 45 and 70 years , and has one of the worse survival rates of all the types of cancer . Two papers are included in this special issue on lung cancer research . Pattichis et al. evaluate new mathematical models that are based on statistics , logic functions , and several statistical classifiers to analyze reader performance in grading chest radiographs for pneumoconiosis . The technique can be potentially applied to the detection of nodules related to early stages of lung cancer . El-Baz et al. focus on the early diagnosis of pulmonary nodules that may lead to lung cancer . Their methods monitor the development of lung nodules in successive low-dose chest CT scans . They propose a new two-step registration method to align globally and locally two detected nodules . Experments on a relatively large data set demonstrate that the proposed registration method contributes to precise identification and diagnosis of nodule development .It is estimated that almost a quarter of a million people in the USA are living with kidney cancer and that the number increases by 51000 every year . Linguraru et al. propose a computer-assisted radiology tool to assess renal tumors in contrast-enhanced CT for the management of tumor diagnosis and response to treatment . The tool accurately segments , measures , and characterizes renal tumors, and has been adopted in clinical practice . V alidation against manual tools shows high correlation .Neuroblastoma is a cancer of the sympathetic nervous system and one of the most malignant diseases affecting children . Two papers in this field are included in this special issue . Sertel et al. present techniques for classification of the degree of Schwannian stromal development as either stroma-rich or stroma-poor , which is a critical decision factor affecting theprognosis . The classification is based on texture features extracted using co-occurrence statistics and local binary patterns . Their work is useful in helping pathologists in the decision-making process . Kong et al. propose image processing and pattern recognition techniques to classify the grade of neuroblastic differentiation on whole-slide histology images . The presented technique is promising to facilitate grading of whole-slide images of neuroblastoma biopsies with high throughput .This special issue also includes papers which are not derectly focused on the detection or diagnosis of a specific type of cancer but deal with the development of techniques applicable to cancer detection . T a et al. propose a framework of graph-based tools for the segmentation of microscopic cellular images . Based on the framework , automatic or interactive segmentation schemes are developed for color cytological and histological images . T osun et al. propose an object-oriented segmentation algorithm for biopsy images for the detection of cancer . The proposed algorithm uses a homogeneity measure based on the distribution of the objects to characterize tissue components . Colon biopsy images were used to verify the effectiveness of the method ; the segmentation accuracy was improved as compared to its pixel-based counterpart . Narasimha et al. present a machine-learning tool for automatic texton-based joint classification and segmentation of mitochondria in MNT-1 cells imaged using an ion-abrasion scanning electron microscope . The proposed approach has minimal user intervention and can achieve high classification accuracy . El Naqa et al. investigate intensity-volume histogram metrics as well as shape and texture features extracted from PET images to predict a patient’s response to treatment . Preliminary results suggest that the proposed approach could potentially provide better tools and discriminant power for functional imaging in clinical prognosis.We hope that the collection of the selected papers in this special issue will serve as a basis for inspiring further rigorous research in CAD of various types of cancer . We invite you to explore this special issue and benefit from these papers .On behalf of the Editorial Committee , we take this opportunity to gratefully acknowledge the autors and the reviewers for their diligence in abilding by the editorial timeline . Our thanks also go to the Editors-in-Chief of Pattern Recognition , Dr. Robert S. Ledley and Dr.C.Y. Suen , for their encouragement and support for this special issue .英文文献译文数字图像处理和模式识别技术关于检测癌症的应用世界上癌症是对于人类（不论男人还是女人）生命的第二杀手。
数字图像处理soble进行边沿检测
使用sobel算子进行图像边沿检测一.实验原理Sobel算子是图像处理中的算子之一，主要用作边缘检测。
在技术上，它是一离散性差分算子，用来运算图像亮度函数的梯度之近似值。
在图像的任何一点使用此算子，将会产生对应的梯度矢量或是其法矢量.该算子包含两组3x3的矩阵，分别为横向及纵向，将之与图像作平面卷积，即可分别得出横向及纵向的亮度差分近似值。
如果用sobel算子检测图像的边缘的话，可以先分别用Sobel 算子有两个，一个是检测水平边沿的；另一个是检测垂直平边沿的。
并且，Sobel算子对于象素的位置的影响做了加权，因此效果更好。
二．实验程序f=imread('jingwu1.jpg');f=rgb2gray(f);f=im2double(f);%使用垂直Sobel算子，自动选择于阈值[VSFAT Threshold]=edge(f,'sobel','vertical'); %边缘探测figure,imshow(f),title('原始图像'); %显示原始图像figure,imshow(VSFAT),title('垂直图像边缘检测');%显示边缘探测图像%使用水平和垂直Sobel算子，自动选择阈值SFST=edge(f,'sobel',Threshold);figure,imshow(SFST),title('水平和垂直图像边缘检测');%显示边缘探测图像%使用指定45度角Sobel算子滤波器，指定阈值s45=[-2 -1 0;-1 0 1;0 1 2];SFST45=imfilter(f,s45,'replicate');SFST45=SFST45>=Threshold;figure,imshow(SFST45),title('45度角图像边缘检测');%最示边缘探测图像s135=[0 1 2;-1 0 1;-2 -1 0];SFST135=imfilter(f,s135,'replicate');SFST135=SFST135>=Threshold;figure,imshow(SFST135),title('135度角图像边缘检测');%最示边缘探测图像三．实验结果本实验分别对三幅图做了sobel算子边缘检测，结果如下：图一：（简单）四．实验分析本实验中使用sobel算子在4个方向进行了图像边缘的检测，有上述程序运行的结果图可以看出，45度角sobel算子和135度角sobel算子生成的边缘检测图像呈现出浮雕的效果，水平和垂直sobel算子检测出的边缘多于单个方向上检测的边缘。
sobel算子图像边缘检测研究外文翻译
Real-time FPGA Based Implementation of ColorImage Edge DetectionAbstract—Color Image edge detection is very basic and important step for many applications such as image segmentation, image analysis, facial analysis, objects identifications/tracking and many others. The main challenge for real-time implementation of color image edge detection is because of high volume of data to be processed (3 times as compared to gray images). This paper describes the real-time implementation of Sobel operator based color image edge detection using FPGA. Sobel operator is chosen for edge detection due to its property to counteract the noise sensitivity of the simple gradient operator. In order to achieve real-time performance, a parallel architecture is designed, which uses three processing elements to compute edge maps of R, G, and B color components. The architecture is codedusing VHDL, simulated in ModelSim, synthesized using Xilinx ISE 10.1 and implemented on Xilinx ML510 (Virtex-5 FX130T) FPGA platform. The complete system is working at 27 MHz clock frequency. The measured performance of our system for standard PAL (720x576) size images is 50 fps (frames per second) and CIF (352x288) size images is 200 fps.Index Terms—Real-time Color Image Edge Detection, Sobel Operator, FPGA Implementation, VLSI Architecture, Color Edge Detection ProcessorI. INTRODUCTIONHigh speed industrial applications require very accurate and real-time edge detection. Edge detection in gray images does not give very accurate results due to loss of color information during color to gray scale image conversion. Therefore, to achieve desired accuracy, detection of edges in color images is necessary. The main challenge for real-time implementation of color image edge detection is in processing of high volume of data (3 times as compared to gray images) within real-time constraints. Therefore, it is hard to achieve real-time performance of edge detection for PAL sizes color images with serial processors. Due to inherent parallelism property, FPGAs can deliver real-time time performance for such applications. Furthermore, FPGAs provide the possibility to perform algorithm modifications in later stages of the system development [1].The main focus of most of the existing FPGA based implementations for edge detection using Sobel operator has been on achieving real-time performance for gray scale images by using various architectures and different design methodologies. As edge detection is low-level image processing operation, Single Instruction Multiple Data (SIMD) type architectures [2] are very suitable for edge detection to achieve real-time performance. These architectures use multiple data processing elements and therefore, require more FPGA resources. The architecture clockfrequency can be improved by using pipelining. A pipelined architecture for real-time gray image edge detection is presented in [3]. Some computation optimized architectures are presented in [4, 5]. Few more architectures for real-time gray image edge detection are available in [6 - 11]. In [12, 13], the architectures are designed using MA TLAB-Simulink based design methodology.In this paper, we show that real-time Sobel operator based color image edge detection can be achieved by using a FPGA based parallel architecture. For each color component in RGB space, one specific edge computation processor is developed. As Sobel operator is sliding window operator, smart buffer based Memory architecture is used to move the incoming pixels in computing window. The specific datapaths are designed and controller is developed to perform the complete task. The design and simulation is done using VHDL. The design is targeted to Xilinx ML 510 (Virtex –5 FX130T) FPGA platform. The implementation is tested for real world scenario. It can robustly detect the edges in color images.The rest of the paper is organized in the following way . In section 2 we describe the original Sobel operator based edge detection algorithm. We show, in section 3, the customized architecture for algorithm implementation and how each stage works. In section 4, practical tests are evaluated and synthesis results are shown taking into account system performance. Finally conclusions anddiscussions are presented in section 5.II. EDGE DETECTION SCHEMEIn this section the used algorithm is briefly described, for a more detailed description we refer to [14, 15]. The Sobel operator is widely used for edge detection in images. It is based on computing an approximation of thegradient of the image intensity function. The Sobel filter uses two 3x3 spatial masks which are convolved with the original image to calculate the approximations of thegradient. The Sobel operator uses two filters Hx and Hy.⎥⎥⎥⎦⎤⎢⎢⎢⎣⎡---=101202101X H (1)⎥⎥⎥⎦⎤⎢⎢⎢⎣⎡=1211001-2-1-y H (2)These filters compute the gradient components across the neighboring lines or columns, respectively. The smoothing is performed over three lines or columns before computing the respective gradients. In this Sobel operator, the higher weights are assigned in smoothing part to current center line and column as compared to simple gradient operators. The local edge strength is defined as the gradient magnitude given by equation 3.()22,Hy Hx y x GM += (3)This equation 3 is computationally costly because of square and square root operations for every pixel. It is more suitable computationally to approximate the square and square root operations by absolute values.()Hy Hx y x GM +=, (4)This expression is much easy to compute and still preserves the relative changes in intensity (edges in images).This above mentioned scheme is for gray scale images. For color images (RGB color space) this scheme is applied separately for each color component. Final color edge map of color image is computed by using the edge maps of each color component [16].)(B Edge or G Edge or EdgeR ColorEdge (5)III. PROPOSED ARCHITECTURETo detect edges in real-time in PAL (720x576) size color images, dedicated hardware architecture is implemented for Sobel operator based edge detection scheme. Fig. 1 shows the conceptual block diagram of complete system. The hardware setup includes a video camera, a video daughter card, and FPGA board. The video output of camera connects to Digilent VDEC1 Video Decoder Board which is interfaced with Xilinx ML510 (V irtex –5 FX130T) board using Interface PCB. Display Monitor is connected to the board using DVI connector. The video signals are decoded in Camera Interface Module. The output RGB data of camera interface module is applied to edge detection block. The edge detected output from the Edge Detection Block is displayed on the display monitor using DVI controller. The camera interface module also generates video timing signals which are necessary for proper functioning of edge detection block and DVI controller. A more detailed description of this Camera Interface Design can be found in[17].Figure 1. Complete System Block DiagramFig. 2 shows the basic block level data flow diagram for computation of edges in color images using Sobel operator. The goal is to perform edge detection three times, once each for red, green, and blue, and then the output is fused to form one edge map [16]. There are mainly four stages. First stage is Buffer Memory stage. In this stage, the three color components are separated andstored in three different memories. The second stage is gradient computation stage. In this stage the gradient is computed for each color component by adding absolute values of horizontal and vertical gradients. In third stage, the edge map is computed for each color component by comparing the gradient values with threshold. Final edge map is computed by combining the edge maps of each color components in stage four.Figure 2. Edge Detection in Color Images using Sobel OperatorThe streaming data processing cannot be used because the edge detection using Sobel operator algorithm is window based operation. Therefore, input data from camera is stored in on-chip memory (BRAM and Registers) before processing it on FPGA. The Sobel edge detection logic can begin processing as soon as two rows arrived in Buffer Memory. The Smart Buffer based Buffer Memory architecture [18] is used in the proposed Sobel operator based color edge detection implementation for data buffering. This approach (Fig. 3) works if one image pixel is coming from camera interface module in one clock cycle. The pixels are coming row by row. When buffers are filled, this architecture provides the access to the entire pixel neighborhood every clock cycle. The architecture places the highest demand on internal memory bandwidth. Because modern FPGA devices contain large amount of embedded memory, this approach does not cause problems [19]. The length of the shift registers depends on the width of input image. ForPAL (720x576) size images the length of FIFOs is 717 (i.e. 720 - 3). For CIF (352x288) size images, it is 349 (i.e. 352 – 3).Figure 3. Sliding Window Memory Buffer ArchitectureThe absolute values of gradient Hx and Hy for pixel data P2,2 is given by following expressions.())())*21333123,21,13,1，，，（（P P P P P P Hx -+-+-= (6)())())*23,1332,12,31,11,3P P P P P P Hy -+-+-=，（（ (7)The processing modules architectures for computing these horizontal and vertical gradients for each color components are shown in Fig. 4. Both the architectures are same except the inputs applied to them at a particular time. Each processing module performs additions, subtractions, and multiplication. The multiplication is costly in digital hardware but multiplication by 2 is easily achieved by shift operation.The complete architecture (Fig. 5) uses three processing elements in parallel (each for R, G , and B color components). The data coming from camera interface module is 24-bit RGB data. Incoming data is separated in three color components R, G , and B. Each color component data is of 8-bit (i.e. any value from 0 to 255). Three smart buffer based Sliding Window Memories are used to store two rows of the three color components. Each memory uses two First-in First-out (FIFO) shift-registers and 9 registers. The width of FIFOs and registers is 8-bit. Therefore, in total 6 FIFOs and 27 registers are required for designing Sliding Window Buffer Memory for RGB color image edge detection architecture. The designing of FIFOs using available registers in FPGA occupies large area in FPGA. Therefore, available Block RAMs on FPGA are used for designing the FIFOs. This resulted in efficient utilization of FPGA resources.Figure 4. Gradient Hx and Hy Computation Module ArchitecturesFor detecting edge in PAL (720x576) size color images, it takes 1440 (720x2) clock cycles to fill the two rows of image data in buffer memory. After this, in every clock cycle, each color component (R, G , and B) of new pixel is moved in their respective computing window (consists of 9 registers). The available 9 pixels in computing window (P1,1, P1,2, P1,3, P2,1, P2,2, P2,3, P3,1, P3,2, P3,3) are used for computing the Hx and Hy gradient values. These are computed according to equations 6 and 7 by using the processing module architectures shown in Fig 4. The approximate magnitude of the gradient is computed along each color component by adding the absolute values of Hx and Hy. After this, the approximate gradient of each color component is compared with a user defined threshold value. If the approximate value of gradient is more than the user defined threshold, the comparator output for that color component is 1 else it is 0. Theoutputs of all three comparators (R, G, and B) are finally fused to find the final edge map. The final edge map is computed by ORing the Edge Map outputs of each color component. It requires one three input OR gate. If the final edge map output is one, the each color component value is set to 11111111 else it is set to 00000000. These values are used by DVI controller to display the result on display Monitor.Figure 5. Complete Architecture for Color Image Edge Detection using Sobel OperatorIV. RESULTSThe proposed architecture is designed using VHDL and simulated in ModelSim. Synthesis is carried out using Xilinx ISE 10.3. Final design is implemented on Xilinx ML510 (Virtex–5 FX130T) FPGA board. It utilizes 294 Slice Registers, 592 Slice LUTs, 206 FPGA Slices, 642 LUT Flip Flop Pairs, 116 Route-thrus and 3 Block RAMS. The synthesis results (Table I) reveal that the FPGA resources utilized by proposed architecture are approximately 1% of total available resources. The FPGA resource utilization table is only for proposed color image edge detection architecture (i.e. buffer memory, gradient computation, edge map computation) and excludes the resources utilized by camera interface and display logic. The measured performance of our system at 27 MHz operating frequency for PAL (720x576) size images is 50 fps (frames per second), CIF (352x288) size images is 200 fps and QCIF (176x144) size images is 800 fps. PAL and CIF images are most commonly used video formats. Therefore, implemented system can easily detect edges in color images in real-time.TABLE I. SYNTHESIS RESULTSFigure 6. Input Color Image and Output Edge Detected ImageFigure 7. Input Color Image and Output Edge Detected ImageFigure 8. Input Color Image and Output Edge Detected ImageFigure 9. Complete SystemIn Fig. 6-8, the input PAL (720x576) size color test images taken from camera and respective output edge detected images produced by proposed architectures are shown. Fig. 9 shows the complete system. The images are captured by using Sony EVI D70P analog camera, processed by designed VLSI architecture running on FPGA, and displayed on monitor.V. CONCLUSIONIn this paper, the hardware architecture for Sobel operator based color image edge detection scheme has been presented. The architecture used approximately 1% of total FPGA resources and maintained real-time constraints of video processing. The system is tested for various real world situations and it robustly detects the edge in real-time with a frame rate of 50 fps for standard PAL video (60 fps for NTSC video) in color scale. The speed could be further improved by adding pipelining stages in gradient computation modules at the expense of increasing FPGA resources usage. The Xilinx ML510 (Virtex-5 FX130T) FPGA board is chosen for this implementation due to availability of large number of FPGA resources, Block RAMs, and PowerPC processor (for hardware-software co-design) so that same board can be used to implement other complex computer vision algorithms which make use of edge detection architecture. The proposed architecture is very suitable for high frame rate industrial applications. The future work will look at the use of this architecture for finding the focused areas in a scene for surveillance applications.A CKNOWLEDGMENTThe authors express their deep sense of gratitude to Director, Dr. Chandra Shekhar, forencouraging research and development. Also the authors would like to express their sincerethanks to Dr. AS Mandal and Group Leader, Raj Singh,for their precious suggestions in refining the research work. Authors specially thank Mr. Sanjeev Kumar, Technical Officer, for tool related support. We thank to reviewers, whose constructive suggestions have improved the quality of this research paper.REFERENCES[1] H. Jiang, H. Ardo, and V. Owall (2009), A Hardware Architecture for Real-Time Video Segmentation Utilizing Memory Reduction Techniques, IEEE Transactions on Circuits and Systems for V ideo Technology, vol. 19, no. 2, pp. 226–236.[2] R.L. Rosas, A.D. Luca, and F.B. Santillan (2005), SIMD Architecture for Image Segmentation using Sobel Operators Implemented in FPGA Technology, In Proceedings of 2nd International Conference on Electrical and Electronics Engineering, pp. 77-80.[3] T.A. Abbasi and M.U. Abbasi (2007), A Novel FPGA-based Architecture for Sobel Edge Detection Operator, International Journal of Electronics, vol. 94, no. 9, pp. 889-896, 2007.[4] Z.E.M. Osman, F.A. Hussin, And N.B.Z. Ali (2010a), Hardware Implementation of an Optimized Processor Architecture for Sobel Image Edge Detection Operator, In Proceeding of International Conference on Intelligent and Advanced Systems (ICIAS), pp. 1-4.[5] Z.E.M. Osman, F.A. Hussin, And N.B.Z. Ali (2010b), Optimization of Processor Architecture for Image Edge Detection Filter, In Proceeding of International Conference on Computer Modeling and Simulation, pp. 648-652[6] I. Y asri, N.H. Hamid, And V.V. Y ap (2008), Performance Analysis of FPGA based Sobel Edge Detection Operator, In Proceedings of International Conference on Electronic Design, pp. 1-4. [7] V. Sanduja and R. Patial (2012), Sobel Edge Detection using Parallel Architecture based on FPGA, International Journal of Applied Information Systems, vol. 3, no. 4, pp. 20-24.[8] G. Anusha, T.J. Prasad, and D.S. Narayana (2012), Implementation of SOBEL Edge Detection on FPGA, International Journal of Computer Trends and Technology, vol. 3, no. 3, pp. 472-475. [9] L.P. Latha (2012), Design of Edge Detection Technique Using FPGA(Field Programmable Gate Array) and DSP (Digital Signal Processor), VSRD International Journal of Electrical, Electronics & Communication Engineering, vol. 2, no. 6, pp. 346-352.[10] A.R. Ibrahim, N.A. Wahed, N. Shinwari, and M.A. Nasser (2011), Hardware Implementation of Real Time Video Edge Detection With Adjustable Threshold Level (Edge Sharpness) Using Xilinx Spartan-3A FPGA, Report.[11] P.S. Chikkali and K. Prabhushetty (2011), FPGA based Image Edge Detection and Segmentation, International Journal of Advanced Engineering Sciences and Technologies, V ol. 9, Issue 2, pp. 187-192.[12] R. Harinarayan, R. Pannerselvam, M.M. Ali, And D.K. Tripathi (2011), Feature extraction of Digital Aerial Images by FPGA based implementation of edge detection algorithms, In Proceedings of International Conference on Emerging Trends in Electrical and Computer Technology, pp. 631-635.[13] K.C. Sudeep and J. Majumdar (2011), A Novel Architecture for Real Time Implementation of Edge Detectors on FPGA, International Journal of Computer Science Issues, vol. 8, no. 1, pp. 193-202.[14] W. Burger and M.J. Burge (2008), Digital Image Processing: An Algorithmic Introduction Using Java, New Y ork: Springer, 120-123.中文翻译：基于FPGA的实时彩色实现图像边缘检测Sanjay Singh Saini *，阿尼尔库马尔，拉维赛尼IC设计组CSIR中央电子工程研究所，拉贾斯坦，印度333031个学位-。
边缘检测外文翻译--一个索贝尔图像边缘检测算法描述
译文一：1一个索贝尔图像边缘检测算法描述[1]摘要：图像边缘检测是一个确定图像边缘的过程，在输入的灰度图中的各个点寻找绝对梯度近似级对于边缘检测是非常重要的。
为边缘获得适当的绝对梯度幅度主要在与使用的方法。
Sobel算子就是在图像上进行2-D的空间梯度测量。
转换2-D像素列阵到性能统计数据集提高了数据冗余消除，因此，作为代表的数字图像，数据量的减少是需要的。
Sobel边缘检测器采用一对3×3的卷积模板，一块估计x－方向的梯度，另一块估计y－方向的梯度。
Sobel检测器对于图像中的噪音很敏感，它能有效地突出边缘。
因此，Sobel算子被建议用在数据传输中的大量数据通信。
关键词：图像处理，边缘检测，Sobel算子，通信数据，绝对梯度幅度。
引言图像处理在现代数据储存和数据传输方面十分重要，特别是图像的渐进传输，视频编码(电话会议)，数字图书馆，图像数据库以及遥感。
它与处理靠算法产生所需的图像有关(Milan et al., 2003)。
数字图像处理(DSP)提高了在极不利条件下所拍摄的图像的质量，具体方法有：调整亮度与对比度，边缘检测，降噪，调整重点，减少运动模糊等(Gonzalez, 2002)。
图像处理允许更广泛的范围被应用到输入数据，以避免如噪声和信号失真集结在加工过程中存在的问题(Baker & Nayar, 1996)。
在19世纪60年代的Jet Propulsion实验室，美国麻省理工学院(MIT)，贝尔实验室以及一些其他的地方，数字图像处理技术不断发展。
但是，因为当时的计算设备关系，处理的成本却很高。
随着20世纪快速计算机和信号处理器的应用，数字图像处理变成了图像处理最通用的形式，因为它不只是最多功能的，还是最便宜的。
图像处理过程中允许一些更复杂算法的使用，从而可以在简单任务中提供更先进的性能，同时可以实现模拟手段不能实现的方法(Micheal, 2003)。
因此，计算机搜集位表示像素或者点形成的图片元素，以此储存在电脑中(Vincent, 2006)。
数字图像处理 外文翻译 外文文献 英文文献 数字图像处理
数字图像处理外文翻译外文文献英文文献数字图像处理Digital Image Processing1 IntroductionMany operators have been proposed for presenting a connected component n a digital image by a reduced amount of data or simplied shape. In general we have to state that the development, choice and modi_cation of such algorithms in practical applications are domain and task dependent, and there is no \best method". However, it isinteresting to note that there are several equivalences between published methods and notions, and characterizing such equivalences or di_erences should be useful to categorize the broad diversity of published methods for skeletonization. Discussing equivalences is a main intention of this report.1.1 Categories of MethodsOne class of shape reduction operators is based on distance transforms. A distance skeleton is a subset of points of a given component such that every point of this subset represents the center of a maximal disc (labeled with the radius of this disc) contained in the given component. As an example in this _rst class of operators, this report discusses one method for calculating a distance skeleton using the d4 distance function which is appropriate to digitized pictures. A second class of operators produces median or center lines of the digitalobject in a non-iterative way. Normally such operators locate critical points _rst, and calculate a speci_ed path through the object by connecting these points.The third class of operators is characterized by iterative thinning. Historically, Listing [10] used already in 1862 the term linear skeleton for the result of a continuous deformation of the frontier of a connected subset of a Euclidean space without changing the connectivity of the original set, until only a set of lines and points remains. Many algorithms in image analysis are based on this general concept of thinning. The goal is a calculation of characteristic properties of digital objects which are not related to size or quantity. Methods should be independent from the position of a set in the plane or space, grid resolution (for digitizing this set) or the shape complexity of the given set. In the literature the term \thinning" is not used - 1 -in a unique interpretation besides that it always denotes a connectivity preserving reduction operation applied to digital images, involving iterations of transformations of speci_ed contour points into background points. A subset Q _ I of object points is reduced by ade_ned set D in one iteration, and the result Q0 = Q n D becomes Q for the next iteration. Topology-preserving skeletonization is a special case of thinning resulting in a connected set of digital arcs or curves.A digital curve is a path p =p0; p1; p2; :::; pn = q such that pi is a neighbor of pi?1, 1 _ i _ n, and p = q. A digital curve is called simpleif each point pi has exactly two neighbors in this curve. A digital arc is a subset of a digital curve such that p 6= q. A point of a digital arc which has exactly one neighbor is called an end point of this arc. Within this third class of operators (thinning algorithms) we may classify with respect to algorithmic strategies: individual pixels are either removed in a sequential order or in parallel. For example, the often cited algorithm by Hilditch [5] is an iterative process of testing and deleting contour pixels sequentially in standard raster scan order. Another sequential algorithm by Pavlidis [12] uses the de_nition of multiple points and proceeds by contour following. Examples of parallel algorithms in this third class are reduction operators which transform contour points into background points. Di_erences between these parallel algorithms are typically de_ned by tests implemented to ensure connectedness in a local neighborhood. The notion of a simple point is of basic importance for thinning and it will be shown in this reportthat di_erent de_nitions of simple points are actually equivalent. Several publications characterize properties of a set D of points (to be turned from object points to background points) to ensure that connectivity of object and background remain unchanged. The report discusses some of these properties in order to justify parallel thinning algorithms.1.2 BasicsThe used notation follows [17]. A digital image I is a functionde_ned on a discrete set C , which is called the carrier of the image.The elements of C are grid points or grid cells, and the elements (p;I(p)) of an image are pixels (2D case) or voxels (3D case). The range of a (scalar) image is f0; :::Gmaxg with Gmax _ 1. The range of a binary image is f0; 1g. We only use binary images I in this report. Let hIi be the set of all pixel locations with value 1, i.e. hIi = I?1(1). The image carrier is de_ned on an orthogonal grid in 2D or 3D - 2 -space. There are two options: using the grid cell model a 2D pixel location p is a closed square (2-cell) in the Euclidean plane and a 3D pixel location is a closed cube (3-cell) in the Euclidean space, where edges are of length 1 and parallel to the coordinate axes, and centers have integer coordinates. As a second option, using the grid point model a 2D or 3D pixel location is a grid point.Two pixel locations p and q in the grid cell model are called 0-adjacent i_ p 6= q and they share at least one vertex (which is a 0-cell). Note that this speci_es 8-adjacency in 2D or 26-adjacency in 3D if the grid point model is used. Two pixel locations p and q in the grid cell model are called 1- adjacent i_ p 6= q and they share at least one edge (which is a 1-cell). Note that this speci_es 4-adjacency in 2D or 18-adjacency in 3D if the grid point model is used. Finally, two 3Dpixel locations p and q in the grid cell model are called 2-adjacent i_ p 6= q and they share at least one face (which is a 2-cell). Note that this speci_es 6-adjacency if the grid point model is used. Any of these adjacency relations A_, _ 2 f0; 1; 2; 4; 6; 18; 26g, is irreexive andsymmetric on an image carrier C. The _-neighborhood N_(p) of a pixel location p includes p and its _-adjacent pixel locations. Coordinates of 2D grid points are denoted by (i; j), with 1 _ i _ n and 1 _ j _ m; i; j are integers and n;m are the numbers of rows and columns of C. In 3Dwe use integer coordinates (i; j; k). Based on neighborhood relations wede_ne connectedness as usual: two points p; q 2 C are _-connected with respect to M _ C and neighborhood relation N_ i_ there is a sequence of points p = p0; p1; p2; :::; pn = q such that pi is an _-neighbor of pi?1, for 1 _ i _ n, and all points on this sequence are either in M or all in the complement of M. A subset M _ C of an image carrier is called _-connected i_ M is not empty and all points in M are pairwise _-connected with respect to set M. An _-component of a subset S of C is a maximal _-connected subset of S. The study of connectivity in digital images has been introduced in [15]. It follows that any set hIi consists of a number of _-components. In case of the grid cell model, a component is the union of closed squares (2D case) or closed cubes (3D case). The boundary of a 2-cell is the union of its four edges and the boundary of a 3-cell is the union of its six faces. For practical purposes it iseasy to use neighborhood operations (called local operations) on adigital image I which de_ne a value at p 2 C in the transformed image based on pixel- 3 -values in I at p 2 C and its immediate neighbors in N_(p).2 Non-iterative AlgorithmsNon-iterative algorithms deliver subsets of components in specied scan orders without testing connectivity preservation in a number of iterations. In this section we only use the grid point model.2.1 \Distance Skeleton" AlgorithmsBlum [3] suggested a skeleton representation by a set of symmetric points.In a closed subset of the Euclidean plane a point p is called symmetric i_ at least 2 points exist on the boundary with equal distances to p. For every symmetric point, the associated maximal discis the largest disc in this set. The set of symmetric points, each labeled with the radius of the associated maximal disc, constitutes the skeleton of the set. This idea of presenting a component of a digital image as a \distance skeleton" is based on the calculation of a speci_ed distance from each point in a connected subset M _ C to the complement of the subset. The local maxima of the subset represent a \distance skeleton". In [15] the d4-distance is specied as follows. De_nition 1 The distance d4(p; q) from point p to point q, p 6= q, is the smallest positive integer n such that there exists a sequence of distinct grid points p = p0,p1; p2; :::; pn = q with pi is a 4-neighbor of pi?1, 1 _ i _ n.If p = q the distance between them is de_ned to be zero. Thedistance d4(p; q) has all properties of a metric. Given a binary digital image. We transform this image into a new one which represents at each point p 2 hIi the d4-distance to pixels having value zero. The transformation includes two steps. We apply functions f1 to the image Iin standard scan order, producing I_(i; j) = f1(i; j; I(i; j)), and f2in reverse standard scan order, producing T(i; j) = f2(i; j; I_(i; j)), as follows:f1(i; j; I(i; j)) =8><>>:0 if I(i; j) = 0minfI_(i ? 1; j)+ 1; I_(i; j ? 1) + 1gif I(i; j) = 1 and i 6= 1 or j 6= 1- 4 -m+ n otherwisef2(i; j; I_(i; j)) = minfI_(i; j); T(i+ 1; j)+ 1; T(i; j + 1) + 1g The resulting image T is the distance transform image of I. Notethat T is a set f[(i; j); T(i; j)] : 1 _ i _ n ^ 1 _ j _ mg, and let T_ _ T such that [(i; j); T(i; j)] 2 T_ i_ none of the four points in A4((i; j)) has a value in T equal to T(i; j)+1. For all remaining points (i; j) let T_(i; j) = 0. This image T_ is called distance skeleton. Now weapply functions g1 to the distance skeleton T_ in standard scan order, producing T__(i; j) = g1(i; j; T_(i; j)), and g2 to the result of g1 in reverse standard scan order, producing T___(i; j) = g2(i; j; T__(i; j)), as follows:g1(i; j; T_(i; j)) = maxfT_(i; j); T__(i ? 1; j)? 1; T__(i; j ? 1) ? 1gg2(i; j; T__(i; j)) = maxfT__(i; j); T___(i + 1; j)? 1; T___(i; j + 1) ? 1gThe result T___ is equal to the distance transform image T. Both functions g1 and g2 de_ne an operator G, with G(T_) = g2(g1(T_)) = T___, and we have [15]: Theorem 1 G(T_) = T, and if T0 is any subset of image T (extended to an image by having value 0 in all remaining positions) such that G(T0) = T, then T0(i; j) = T_(i; j) at all positions of T_with non-zero values. Informally, the theorem says that the distance transform image is reconstructible from the distance skeleton, and it is the smallest data set needed for such a reconstruction. The useddistance d4 di_ers from the Euclidean metric. For instance, this d4-distance skeleton is not invariant under rotation. For an approximation of the Euclidean distance, some authors suggested the use of di_erent weights for grid point neighborhoods [4]. Montanari [11] introduced a quasi-Euclidean distance. In general, the d4-distance skeleton is a subset of pixels (p; T(p)) of the transformed image, and it is not necessarily connected.2.2 \Critical Points" AlgorithmsThe simplest category of these algorithms determines the midpointsof subsets of connected components in standard scan order for each row. Let l be an index for the number of connected components in one row of the original image. We de_ne the following functions for 1 _ i _ n: ei(l) = _ j if this is the lth case I(i; j) = 1 ^ I(i; j ? 1) = 0 in row i, counting from the left, with I(i;?1) = 0 ，oi(l) = _ j if this is the lth case I(i; j) = 1- 5 -^ I(i; j+ 1) = 0 ，in row i, counting from the left, with I(i;m+ 1)= 0 ，mi(l) = int((oi(l) ?ei(l)=2)+ oi(l) ，The result of scanning row i is a set ofcoordinates (i;mi(l)) ofof the connected components in row i. The set of midpoints of all rows midpoints ，constitutes a critical point skeleton of an image I. This method is computationally eÆcient.The results are subsets of pixels of the original objects, and these subsets are not necessarily connected. They can form \noisy branches" when object components are nearly parallel to image rows. They may be useful for special applications where the scanning direction is approximately perpendicular to main orientations of object components.References[1] C. Arcelli, L. Cordella, S. Levialdi: Parallel thinning ofbinary pictures. Electron. Lett. 11:148{149, 1975}.[2] C. Arcelli, G. Sanniti di Baja: Skeletons of planar patterns. in: Topolog- ical Algorithms for Digital Image Processing (T. Y. Kong, A. Rosenfeld, eds.), North-Holland, 99{143, 1996.}[3] H. Blum: A transformation for extracting new descriptors of shape. in: Models for the Perception of Speech and Visual Form (W. Wathen- Dunn, ed.), MIT Press, Cambridge, Mass., 362{380, 1967.19} - 6 -数字图像处理1引言许多研究者已提议提出了在数字图像里的连接组件是由一个减少的数据量或简化的形状。
介绍数字图像处理外文翻译
附录1 外文原文Source: "the 21st century literature the applied undergraduate electronic communication series of practical teaching planThe information and communication engineering specialty in English ch02_1. PDF 120-124Ed: HanDing ZhaoJuMin, etcText A: An Introduction to Digital Image Processing1. IntroductionDigital image processing remains a challenging domain of programming for several reasons. First the issue of digital image processing appeared relatively late in computer history. It had to wait for the arrival of the first graphical operating systems to become a true matter. Secondly, digital image processing requires the most careful optimizations especially for real time applications. Comparing image processing and audio processing is a good way to fix ideas. Let us consider the necessary memory bandwidth for examining the pixels of a 320x240, 32 bits bitmap, 30 times a second: 10 Mo/sec. Now with the same quality standard, an audio stereo wave real time processing needs 44100 (samples per second) x 2 (bytes per sample per channel) x 2(channels) = 176Ko/sec, which is 50 times less.Obviously we will not be able to use the same techniques for both audio and image signal processing. Finally, digital image processing is by definition a two dimensions domain; this somehow complicates things when elaborating digital filters.We will explore some of the existing methods used to deal with digital images starting by a very basic approach of color interpretation. As a moreadvanced level of interpretation comes the matrix convolution and digital filters. Finally, we will have an overview of some applications of image processing.The aim of this document is to give the reader a little overview of the existing techniques in digital image processing. We will neither penetrate deep into theory, nor will we in the coding itself; we will more concentrate on the algorithms themselves, the methods. Anyway, this document should be used as a source of ideas only, and not as a source of code. 2. A simple approach to image processing(1) The color data: Vector representation①BitmapsThe original and basic way of representing a digital colored image in a computer's memory is obviously a bitmap. A bitmap is constituted of rows of pixels, contraction of the word s “Picture Element”. Each pixel has a particular value which determines its appearing color. This value is qualified by three numbers giving the decomposition of the color in the three primary colors Red, Green and Blue. Any color visible to human eye can be represented this way. The decomposition of a color in the three primary colors is quantified by a number between 0 and 255. For example, white will be coded as R = 255, G = 255, B = 255; black will be known as (R,G,B)= (0,0,0); and say, bright pink will be : (255,0,255). In other words, an image is an enormous two-dimensional array of color values, pixels, each of them coded on 3 bytes, representing the three primary colors. This allows the image to contain a total of 256×256×256 = 16.8 million different colors. This technique is also known as RGB encoding, and is specifically adapted to human vision. With cameras or other measure instruments we are capable of “seeing”thousands of other “colors”, in which cases the RG B encoding is inappropriate.The range of 0-255 was agreed for two good reasons: The first is that the human eye is not sensible enough to make the difference between more than 256 levels of intensity (1/256 = 0.39%) for a color. That is to say, an image presented to a human observer will not be improved by using more than 256 levels of gray (256shades of gray between black and white). Therefore 256 seems enough quality. The second reason for the value of 255 is obviously that it is convenient for computer storage. Indeed on a byte, which is the computer's memory unit, can be coded up to 256 values.As opposed to the audio signal which is coded in the time domain, the image signal is coded in a two dimensional spatial domain. The raw image data is much more straightforward and easy to analyze than the temporal domain data of the audio signal. This is why we will be able to do lots of stuff and filters for images without transforming the source data, while this would have been totally impossible for audio signal. This first part deals with the simple effects and filters you can compute without transforming the source data, just by analyzing the raw image signal as it is.The standard dimensions, also called resolution, for a bitmap are about 500 rows by 500 columns. This is the resolution encountered in standard analogical television and standard computer applications. You can easily calculate the memory space a bitmap of this size will require. We have 500×500 pixels, each coded on three bytes, this makes 750 Ko. It might not seem enormous compared to the size of hard drives, but if you must deal with an image in real time then processing things get tougher. Indeed rendering images fluidly demands a minimum of 30 images per second, the required bandwidth of 10 Mo/sec is enormous. We will see later that the limitation of data access and transfer in RAM has a crucial importance in image processing, and sometimes it happens to be much more important than limitation of CPU computing, which may seem quite different from what one can be used to in optimization issues. Notice that, with modern compression techniques such as JPEG 2000, the total size of the image can be easily reduced by 50 times without losing a lot of quality, but this is another topic.②Vector representation of colorsAs we have seen, in a bitmap, colors are coded on three bytes representing their decomposition on the three primary colors. It sounds obvious to a mathematician to immediately interpret colors as vectors in athree-dimension space where each axis stands for one of the primary colors. Therefore we will benefit of most of the geometric mathematical concepts to deal with our colors, such as norms, scalar product, projection, rotation or distance. This will be really interesting for some kind of filters we will see soon. Figure 1 illustrates this new interpretation:Figure 1(2) Immediate application to filters① Edge DetectionFrom what we have said before we can quantify the 'difference' between two colors by computing the geometric distance between the vectors representing those two colors. Lets consider two colors C1 = (R1,G1,B1) and C2 = (R2,B2,G2), the distance between the two colors is given by the formula :D(C1, C2) =(R1+This leads us to our first filter: edge detection. The aim of edge detection is to determine the edge of shapes in a picture and to be able to draw a resultbitmap where edges are in white on black background (for example). The idea is very simple; we go through the image pixel by pixel and compare the color of each pixel to its right neighbor, and to its bottom neighbor. If one of these comparison results in a too big difference the pixel studied is part of an edge and should be turned to white, otherwise it is kept in black. The fact that we compare each pixel with its bottom and right neighbor comes from the fact that images are in two dimensions. Indeed if you imagine an image with only alternative horizontal stripes of red and blue, the algorithms wouldn't see the edges of those stripes if it only compared a pixel to its right neighbor. Thus the two comparisons for each pixel are necessary.This algorithm was tested on several source images of different types and it gives fairly good results. It is mainly limited in speed because of frequent memory access. The two square roots can be removed easily by squaring the comparison; however, the color extractions cannot be improved very easily. If we consider that the longest operations are the get pixel function and put pixel functions, we obtain a polynomial complexity of 4*N*M, where N is the number of rows and M the number of columns. This is not reasonably fast enough to be computed in realtime. For a 300×300×32 image I get about 26 transforms per second on an Athlon XP 1600+. Quite slow indeed.Here are the results of the algorithm on an example image:A few words about the results of this algorithm: Notice that the quality of the results depends on the sharpness of the source image. Ifthe source image is very sharp edged, the result will reach perfection. However if you have a very blurry source you might want to make it pass through a sharpness filter first, which we will study later. Another remark, you can also compare each pixel with its second or third nearest neighbors on the right and on the bottom instead of the nearest neighbors. The edges will be thicker but also more exact depending on the source image's sharpness. Finally we will see later on that there is another way to make edge detection with matrix convolution.②Color extractionThe other immediate application of pixel comparison is color extraction.Instead of comparing each pixel with its neighbors, we are going to compare it with a given color C1. This algorithm will try to detect all the objects in the image that are colored with C1. This was quite useful for robotics for example. It enables you to search on streaming images for a particular color. You can then make you robot go get a red ball for example. We will call the reference color, the one we are looking for in the image C0 = (R0,G0,B0).Once again, even if the square root can be easily removed it doesn't really improve the speed of the algorithm. What really slows down the whole loop is the NxM get pixel accesses to memory and put pixel. This determines the complexity of this algorithm: 2xNxM, where N and M are respectively the numbers of rows and columns in the bitmap. The effective speed measured on my computer is about 40 transforms per second on a 300x300x32 source bitmap.3.JPEG image compression theory(一)JPEG compression is divided into four steps to achieve:(1) Color mode conversion and samplingRGB color system is the most common ways that color. JPEG uses a YCbCr colorsystem. Want to use JPEG compression method dealing with the basic full-color images, RGB color mode to first image data is converted to YCbCr color model data. Y representative of brightness, Cb and Cr represents the hue, saturation. By the following calculation to be completed by data conversion. Y = 0.2990R +0.5870 G+0.1140 B Cb =- 0.1687R-0.3313G +0.5000 B +128 Cr = 0.5000R-0.4187G-0.0813B+128 of human eyes on the low-frequency data than high-frequency data with higher The sensitivity, in fact, the human eye to changes in brightness than to color changes should be much more sensitive, ie Y component of the data is more important. Since the Cb and Cr components is relatively unimportant component of the data comparison, you can just take part of the data to deal with. To increase the compression ratio. JPEG usually have two kinds of sampling methods: YUV411 and YUV422, they represent is the meaning of Y, Cb and Cr data sampling ratio of three components.（2）DCT transformationThe full name is the DCT-discrete cosine transform (Discrete Cosine Transform), refers to a group of light intensity data into frequency data, in order that intensity changes of circumstances. If the modification of high-frequency data do, and then back to the original form of data, it is clear there are some differences with the original data, but the human eye is not easy to recognize. Compression, the original image data is divided into 8 * 8 matrix of data units. JPEG entire luminance and chrominance Cb matrix matrix, saturation Cr matrix as a basic unit called the MCU. Each MCU contains a matrix of no more than 10. For example, the ratio of rows and columns Jie Wei 4:2:2 sampling, each MCU will contain four luminance matrix, a matrix and a color saturation matrix. When the image data is divided into an 8 * 8 matrix, you must also be subtracted for each value of 128, and then a generation of formula into the DCT transform can be achieved by DCT transform purposes. The image data value must be reduced by 128, because the formula accepted by the DCT-figure range is between -128 to +127.（3）QuantizationImage data is converted to the frequency factor, you still need to accept a quantitative procedure to enter the coding phase. Quantitative phase requires two 8 * 8 matrix of data, one is to deal specifically with the brightness of the frequency factor, the other is the frequency factor for the color will be the frequency coefficient divided by the value of quantization matrix to obtain the nearest whole number with the quotient, that is completed to quantify. When the frequency coefficients after quantization, will be transformed into the frequency coefficients from the floating-point integer This facilitate the implementation of the final encoding. However, after quantitative phase, all the data to retain only the integer approximation, also once again lost some data content.（4）CodingHuffman encoding without patent issues, to become the most commonly used JPEG encoding, Huffman coding is usually carried out in a complete MCU. Coding, each of the DC value matrix data 63 AC value, will use a different Huffman code tables, while the brightness and chroma also require a different Huffman code tables, it needs a total of four code tables, in order to successfully complete the JPEG coding. DC Code DC is a color difference pulse code modulation using the difference coding method, which is in the same component to obtain an image of each DC value and the difference between the previous DC value to encode. DC pulse code using the main reason for the difference is due to a continuous tone image, the difference mostly smaller than the original value of the number of bits needed to encode the difference will be more than the original value of the number of bits needed to encode the less. For example, a margin of 5, and its binary representation of a value of 101, if the difference is -5, then the first changed to a positive integer 5, and then converted into its 1's complement binary number can be. The so-called one's complement number, that is, if the value is 0 for each Bit, then changed to 1; Bit is 1, it becomes 0. Difference between the five should retain the median 3, the following table that lists the difference between the Bit to be retained and the difference between the number of content controls.In the margin of the margin front-end add some additional value Hoffman code, such as the brightness difference of 5 (101) of the median of three, then the Huffman code value should be 100, the two connected together shall be 100101. The following two tables are the brightness and chroma DC difference encoding table. According to these two forms content, you can add the difference for the DC value Huffman code to complete the DC coding.4. ConclusionsDigital image processing is far from being a simple transpose of audiosignal principles to a two dimensions space. Image signal has its particular properties, and therefore we have to deal with it in a specificway. The Fast Fourier Transform, for example, which was such a practical tool in audio processing, becomes useless in image processing. Oppositely, digital filters are easier to create directly, without any signal transforms, in image processing.Digital image processing has become a vast domain of modern signal technologies. Its applications pass far beyond simple aesthetical considerations, and they include medical imagery, television and multimedia signals, security, portable digital devices, video compression,and even digital movies. We have been flying over some elementarynotions in image processing but there is yet a lot more to explore. Ifyou are beginning in this topic, I hope this paper will have given you thetaste and the motivation to carry on.附录2 外文翻译文献出处：《21 世纪全国应用型本科电子通信系列实用规划教材》之《信息与通信工程专业英语》ch02_1.pdf 120-124页主编：韩定定、赵菊敏等正文：介绍数字图像处理1.导言有几个原因使数字图像处理仍然是一个具有挑战性的领域。
介绍数字图像处理外文翻译
附录1 外文原文Source: "the 21st century literature the applied undergraduate electronic communication series of practical teaching planThe information and communication engineering specialty in English ch02_1. PDF 120-124Ed: HanDing ZhaoJuMin, etcText A: An Introduction to Digital Image Processing1. IntroductionDigital image processing remains a challenging domain of programming for several reasons. First the issue of digital image processing appeared relatively late in computer history. It had to wait for the arrival of the first graphical operating systems to become a true matter. Secondly, digital image processing requires the most careful optimizations especially for real time applications. Comparing image processing and audio processing is a good way to fix ideas. Let us consider the necessary memory bandwidth for examining the pixels of a 320x240, 32 bits bitmap, 30 times a second: 10 Mo/sec. Now with the same quality standard, an audio stereo wave real time processing needs 44100 (samples per second) x 2 (bytes per sample per channel) x 2(channels) = 176Ko/sec, which is 50 times less.Obviously we will not be able to use the same techniques for both audio and image signal processing. Finally, digital image processing is by definition a two dimensions domain; this somehow complicates things when elaborating digital filters.We will explore some of the existing methods used to deal with digital images starting by a very basic approach of color interpretation. As a moreadvanced level of interpretation comes the matrix convolution and digital filters. Finally, we will have an overview of some applications of image processing.The aim of this document is to give the reader a little overview of the existing techniques in digital image processing. We will neither penetrate deep into theory, nor will we in the coding itself; we will more concentrate on the algorithms themselves, the methods. Anyway, this document should be used as a source of ideas only, and not as a source of code. 2. A simple approach to image processing(1) The color data: Vector representation①BitmapsThe original and basic way of representing a digital colored image in a computer's memory is obviously a bitmap. A bitmap is constituted of rows of pixels, contraction of the word s “Picture Element”. Each pixel has a particular value which determines its appearing color. This value is qualified by three numbers giving the decomposition of the color in the three primary colors Red, Green and Blue. Any color visible to human eye can be represented this way. The decomposition of a color in the three primary colors is quantified by a number between 0 and 255. For example, white will be coded as R = 255, G = 255, B = 255; black will be known as (R,G,B)= (0,0,0); and say, bright pink will be : (255,0,255). In other words, an image is an enormous two-dimensional array of color values, pixels, each of them coded on 3 bytes, representing the three primary colors. This allows the image to contain a total of 256×256×256 = 16.8 million different colors. This technique is also known as RGB encoding, and is specifically adapted to human vision. With cameras or other measure instruments we are capable of “seeing”thousands of other “colors”, in which cases the RG B encoding is inappropriate.The range of 0-255 was agreed for two good reasons: The first is that the human eye is not sensible enough to make the difference between more than 256 levels of intensity (1/256 = 0.39%) for a color. That is to say, an image presented to a human observer will not be improved by using more than 256 levels of gray (256shades of gray between black and white). Therefore 256 seems enough quality. The second reason for the value of 255 is obviously that it is convenient for computer storage. Indeed on a byte, which is the computer's memory unit, can be coded up to 256 values.As opposed to the audio signal which is coded in the time domain, the image signal is coded in a two dimensional spatial domain. The raw image data is much more straightforward and easy to analyze than the temporal domain data of the audio signal. This is why we will be able to do lots of stuff and filters for images without transforming the source data, while this would have been totally impossible for audio signal. This first part deals with the simple effects and filters you can compute without transforming the source data, just by analyzing the raw image signal as it is.The standard dimensions, also called resolution, for a bitmap are about 500 rows by 500 columns. This is the resolution encountered in standard analogical television and standard computer applications. You can easily calculate the memory space a bitmap of this size will require. We have 500×500 pixels, each coded on three bytes, this makes 750 Ko. It might not seem enormous compared to the size of hard drives, but if you must deal with an image in real time then processing things get tougher. Indeed rendering images fluidly demands a minimum of 30 images per second, the required bandwidth of 10 Mo/sec is enormous. We will see later that the limitation of data access and transfer in RAM has a crucial importance in image processing, and sometimes it happens to be much more important than limitation of CPU computing, which may seem quite different from what one can be used to in optimization issues. Notice that, with modern compression techniques such as JPEG 2000, the total size of the image can be easily reduced by 50 times without losing a lot of quality, but this is another topic.②Vector representation of colorsAs we have seen, in a bitmap, colors are coded on three bytes representing their decomposition on the three primary colors. It sounds obvious to a mathematician to immediately interpret colors as vectors in athree-dimension space where each axis stands for one of the primary colors. Therefore we will benefit of most of the geometric mathematical concepts to deal with our colors, such as norms, scalar product, projection, rotation or distance. This will be really interesting for some kind of filters we will see soon. Figure 1 illustrates this new interpretation:Figure 1(2) Immediate application to filters① Edge DetectionFrom what we have said before we can quantify the 'difference' between two colors by computing the geometric distance between the vectors representing those two colors. Lets consider two colors C1 = (R1,G1,B1) and C2 = (R2,B2,G2), the distance between the two colors is given by the formula :D(C1, C2) =(R1+This leads us to our first filter: edge detection. The aim of edge detection is to determine the edge of shapes in a picture and to be able to draw a resultbitmap where edges are in white on black background (for example). The idea is very simple; we go through the image pixel by pixel and compare the color of each pixel to its right neighbor, and to its bottom neighbor. If one of these comparison results in a too big difference the pixel studied is part of an edge and should be turned to white, otherwise it is kept in black. The fact that we compare each pixel with its bottom and right neighbor comes from the fact that images are in two dimensions. Indeed if you imagine an image with only alternative horizontal stripes of red and blue, the algorithms wouldn't see the edges of those stripes if it only compared a pixel to its right neighbor. Thus the two comparisons for each pixel are necessary.This algorithm was tested on several source images of different types and it gives fairly good results. It is mainly limited in speed because of frequent memory access. The two square roots can be removed easily by squaring the comparison; however, the color extractions cannot be improved very easily. If we consider that the longest operations are the get pixel function and put pixel functions, we obtain a polynomial complexity of 4*N*M, where N is the number of rows and M the number of columns. This is not reasonably fast enough to be computed in realtime. For a 300×300×32 image I get about 26 transforms per second on an Athlon XP 1600+. Quite slow indeed.Here are the results of the algorithm on an example image:A few words about the results of this algorithm: Notice that the quality of the results depends on the sharpness of the source image. Ifthe source image is very sharp edged, the result will reach perfection. However if you have a very blurry source you might want to make it pass through a sharpness filter first, which we will study later. Another remark, you can also compare each pixel with its second or third nearest neighbors on the right and on the bottom instead of the nearest neighbors. The edges will be thicker but also more exact depending on the source image's sharpness. Finally we will see later on that there is another way to make edge detection with matrix convolution.②Color extractionThe other immediate application of pixel comparison is color extraction.Instead of comparing each pixel with its neighbors, we are going to compare it with a given color C1. This algorithm will try to detect all the objects in the image that are colored with C1. This was quite useful for robotics for example. It enables you to search on streaming images for a particular color. You can then make you robot go get a red ball for example. We will call the reference color, the one we are looking for in the image C0 = (R0,G0,B0).Once again, even if the square root can be easily removed it doesn't really improve the speed of the algorithm. What really slows down the whole loop is the NxM get pixel accesses to memory and put pixel. This determines the complexity of this algorithm: 2xNxM, where N and M are respectively the numbers of rows and columns in the bitmap. The effective speed measured on my computer is about 40 transforms per second on a 300x300x32 source bitmap.3.JPEG image compression theory(一)JPEG compression is divided into four steps to achieve:(1) Color mode conversion and samplingRGB color system is the most common ways that color. JPEG uses a YCbCr colorsystem. Want to use JPEG compression method dealing with the basic full-color images, RGB color mode to first image data is converted to YCbCr color model data. Y representative of brightness, Cb and Cr represents the hue, saturation. By the following calculation to be completed by data conversion. Y = 0.2990R +0.5870 G+0.1140 B Cb =- 0.1687R-0.3313G +0.5000 B +128 Cr = 0.5000R-0.4187G-0.0813B+128 of human eyes on the low-frequency data than high-frequency data with higher The sensitivity, in fact, the human eye to changes in brightness than to color changes should be much more sensitive, ie Y component of the data is more important. Since the Cb and Cr components is relatively unimportant component of the data comparison, you can just take part of the data to deal with. To increase the compression ratio. JPEG usually have two kinds of sampling methods: YUV411 and YUV422, they represent is the meaning of Y, Cb and Cr data sampling ratio of three components.（2）DCT transformationThe full name is the DCT-discrete cosine transform (Discrete Cosine Transform), refers to a group of light intensity data into frequency data, in order that intensity changes of circumstances. If the modification of high-frequency data do, and then back to the original form of data, it is clear there are some differences with the original data, but the human eye is not easy to recognize. Compression, the original image data is divided into 8 * 8 matrix of data units. JPEG entire luminance and chrominance Cb matrix matrix, saturation Cr matrix as a basic unit called the MCU. Each MCU contains a matrix of no more than 10. For example, the ratio of rows and columns Jie Wei 4:2:2 sampling, each MCU will contain four luminance matrix, a matrix and a color saturation matrix. When the image data is divided into an 8 * 8 matrix, you must also be subtracted for each value of 128, and then a generation of formula into the DCT transform can be achieved by DCT transform purposes. The image data value must be reduced by 128, because the formula accepted by the DCT-figure range is between -128 to +127.（3）QuantizationImage data is converted to the frequency factor, you still need to accept a quantitative procedure to enter the coding phase. Quantitative phase requires two 8 * 8 matrix of data, one is to deal specifically with the brightness of the frequency factor, the other is the frequency factor for the color will be the frequency coefficient divided by the value of quantization matrix to obtain the nearest whole number with the quotient, that is completed to quantify. When the frequency coefficients after quantization, will be transformed into the frequency coefficients from the floating-point integer This facilitate the implementation of the final encoding. However, after quantitative phase, all the data to retain only the integer approximation, also once again lost some data content.（4）CodingHuffman encoding without patent issues, to become the most commonly used JPEG encoding, Huffman coding is usually carried out in a complete MCU. Coding, each of the DC value matrix data 63 AC value, will use a different Huffman code tables, while the brightness and chroma also require a different Huffman code tables, it needs a total of four code tables, in order to successfully complete the JPEG coding. DC Code DC is a color difference pulse code modulation using the difference coding method, which is in the same component to obtain an image of each DC value and the difference between the previous DC value to encode. DC pulse code using the main reason for the difference is due to a continuous tone image, the difference mostly smaller than the original value of the number of bits needed to encode the difference will be more than the original value of the number of bits needed to encode the less. For example, a margin of 5, and its binary representation of a value of 101, if the difference is -5, then the first changed to a positive integer 5, and then converted into its 1's complement binary number can be. The so-called one's complement number, that is, if the value is 0 for each Bit, then changed to 1; Bit is 1, it becomes 0. Difference between the five should retain the median 3, the following table that lists the difference between the Bit to be retained and the difference between the number of content controls.In the margin of the margin front-end add some additional value Hoffman code, such as the brightness difference of 5 (101) of the median of three, then the Huffman code value should be 100, the two connected together shall be 100101. The following two tables are the brightness and chroma DC difference encoding table. According to these two forms content, you can add the difference for the DC value Huffman code to complete the DC coding.4. ConclusionsDigital image processing is far from being a simple transpose of audiosignal principles to a two dimensions space. Image signal has its particular properties, and therefore we have to deal with it in a specificway. The Fast Fourier Transform, for example, which was such a practical tool in audio processing, becomes useless in image processing. Oppositely, digital filters are easier to create directly, without any signal transforms, in image processing.Digital image processing has become a vast domain of modern signal technologies. Its applications pass far beyond simple aesthetical considerations, and they include medical imagery, television and multimedia signals, security, portable digital devices, video compression,and even digital movies. We have been flying over some elementarynotions in image processing but there is yet a lot more to explore. Ifyou are beginning in this topic, I hope this paper will have given you thetaste and the motivation to carry on.附录2 外文翻译文献出处：《21 世纪全国应用型本科电子通信系列实用规划教材》之《信息与通信工程专业英语》ch02_1.pdf 120-124页主编：韩定定、赵菊敏等正文：介绍数字图像处理1.导言有几个原因使数字图像处理仍然是一个具有挑战性的领域。
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附录1 译文数字图像处理与边缘检测数字图像处理数字图像处理方法的研究源于两个主要应用领域：其一是为了便于人们分析而对图像信息进行改进：其二是为使机器自动理解而对图像数据进行存储、传输及显示。
一幅图像可定义为一个二维函数f(x,y)，这里x和y是空间坐标，而在任何一对空间坐标（x,y）上的幅值f 称为该点图像的强度或灰度。
当x,y和幅值f 为有限的、离散的数值时，称该图像为数字图像。
数字图像处理是指借用数字计算机处理数字图像，值得提及的是数字图像是由有限的元素组成的，每一个元素都有一个特定的位置和幅值，这些元素称为图像元素、画面元素或像素。
像素是广泛用于表示数字图像元素的词汇。
视觉是人类最高级的感知器官，所以，毫无疑问图像在人类感知中扮演着最重要的角色。
然而，人类感知只限于电磁波谱的视觉波段，成像机器则可覆盖几乎全部电磁波谱，从伽马射线到无线电波。
它们可以对非人类习惯的那些图像源进行加工，这些图像源包括超声波、电子显微镜及计算机产生的图像。
因此，数字图像处理涉及各种各样的应用领域。
图像处理涉及的范畴或其他相关领域（例如，图像分析和计算机视觉）的界定在初创人之间并没有一致的看法。
有时用处理的输入和输出内容都是图像这一特点来界定图像处理的范围。
我们认为这一定义仅是人为界定和限制。
例如，在这个定义下，甚至最普通的计算一幅图像灰度平均值的工作都不能算做是图像处理。
另一方面，有些领域（如计算机视觉）研究的最高目标是用计算机去模拟人类视觉，包括理解和推理并根据视觉输入采取行动等。
这一领域本身是人工智能的分支，其目的是模仿人类智能。
人工智能领域处在其发展过程中的初期阶段，它的发展比预期的要慢的多，图像分析（也称为图像理解）领域则处在图像处理和计算机视觉两个学科之间。
从图像处理到计算机视觉这个连续的统一体内并没有明确的界线。
然而，在这个连续的统一体中可以考虑三种典型的计算处理（即低级、中级和高级处理）来区分其中的各个学科。
低级处理涉及初级操作，如降低噪声的图像预处理，对比度增强和图像尖锐化。
低级处理是以输入、输出都是图像为特点的处理。
中级处理涉及分割（把图像分为不同区域或目标物）以及缩减对目标物的描述，以使其更适合计算机处理及对不同目标的分类（识别）。
中级图像处理是以输入为图像，但输出是从这些图像中提取的特征（如边缘、轮廓及不同物体的标识等）为特点的。
最后，高级处理涉及在图像分析中被识别物体的总体理解，以及执行与视觉相关的识别函数（处在连续统一体边缘）等。
根据上述讨论，我们看到，图像处理和图像分析两个领域合乎逻辑的重叠区域是图像中特定区域或物体的识别这一领域。
这样，在研究中，我们界定数字图像处理包括输入和输出均是图像的处理，同时也包括从图像中提取特征及识别特定物体的处理。
举一个简单的文本自动分析方面的例子来具体说明这一概念。
在自动分析文本时首先获取一幅包含文本的图像，对该图像进行预处理，提取（分割）字符，然后以适合计算机处理的形式描述这些字符，最后识别这些字符，而所有这些操作都在本文界定的数字图像处理的范围内。
理解一页的内容可能要根据理解的复杂度从图像分析或计算机视觉领域考虑问题。
这样，我们定义的数字图像处理的概念将在有特殊社会和经济价值的领域内通用。
数字图像处理的应用领域多种多样，所以文本在内容组织上尽量达到该技术应用领域的广度。
阐述数字图像处理应用范围最简单的一种方法是根据信息源来分类（如可见光、X射线，等等）。
在今天的应用中，最主要的图像源是电磁能谱，其他主要的能源包括声波、超声波和电子（以用于电子显微镜方法的电子束形式）。
建模和可视化应用中的合成图像由计算机产生。
建立在电磁波谱辐射基础上的图像是最熟悉的，特别是X射线和可见光谱图像。
电磁波可定义为以各种波长传播的正弦波，或者认为是一种粒子流，每个粒子包含一定（一束）能量，每束能量成为一个光子。
如果光谱波段根据光谱能量进行分组，我们会得到下图1所示的伽马射线（最高能量）到无线电波（最低能量）的光谱。
如图所示的加底纹的条带表达了这样一个事实，即电磁波谱的各波段间并没有明确的界线，而是由一个波段平滑地过渡到另一个波段。
图像获取是第一步处理。
注意到获取与给出一幅数字形式的图像一样简单。
通常，图像获取包括如设置比例尺等预处理。
图像增强是数字图像处理最简单和最有吸引力的领域。
基本上，增强技术后面的思路是显现那些被模糊了的细节，或简单地突出一幅图像中感兴趣的特征。
一个图像增强的例子是增强图像的对比度，使其看起来好一些。
应记住，增强是图像处理中非常主观的领域，这一点很重要。
图像复原也是改进图像外貌的一个处理领域。
然而，不像增强，图像增强是主观的，而图像复原是客观的。
在某种意义上说，复原技术倾向于以图像退化的数学或概率模型为基础。
另一方面，增强以怎样构成好的增强效果这种人的主观偏爱为基础。
彩色图像处理已经成为一个重要领域，因为基于互联网的图像处理应用在不断增长。
就使得在彩色模型、数字域的彩色处理方面涵盖了大量基本概念。
在后续发展，彩色还是图像中感兴趣特征被提取的基础。
小波是在各种分辨率下描述图像的基础。
特别是在应用中，这些理论被用于图像数据压缩及金字塔描述方法。
在这里，图像被成功地细分为较小的区域。
压缩，正如其名称所指的意思，所涉及的技术是减少图像的存储量，或者在传输图像时降低频带。
虽然存储技术在过去的十年内有了很大改进，但对传输能力我们还不能这样说，尤其在互联网上更是如此，互联网是以大量的图片内容为特征的。
图像压缩技术对应的图像文件扩展名对大多数计算机用户是很熟悉的（也许没注意），如JPG文件扩展名用于JPEG（联合图片专家组）图像压缩标准。
形态学处理设计提取图像元素的工具，它在表现和描述形状方面非常有用。
这一章的材料将从输出图像处理到输出图像特征处理的转换开始。
分割过程将一幅图像划分为组成部分或目标物。
通常，自主分割是数字图像处理中最为困难的任务之一。
复杂的分割过程导致成功解决要求物体被分别识别出来的成像问题需要大量处理工作。
另一方面，不健壮且不稳定的分割算法几乎总是会导致最终失败。
通常，分割越准确，识别越成功。
表示和描述几乎总是跟随在分割步骤的输后边，通常这一输出是未加工的数据，其构成不是区域的边缘（区分一个图像区域和另一个区域的像素集）就是其区域本身的所有点。
无论哪种情况，把数据转换成适合计算机处理的形式都是必要的。
首先，必须确定数据是应该被表现为边界还是整个区域。
当注意的焦点是外部形状特性（如拐角和曲线）时，则边界表示是合适的。
当注意的焦点是内部特性（如纹理或骨骼形状）时，则区域表示是合适的。
则某些应用中，这些表示方法是互补的。
选择一种表现方式仅是解决把原始数据转换为适合计算机后续处理的形式的一部分。
为了描述数据以使感兴趣的特征更明显，还必须确定一种方法。
描述也叫特征选择，涉及提取特征，该特征是某些感兴趣的定量信息或是区分一组目标与其他目标的基础。
识别是基于目标的描述给目标赋以符号的过程。
如上文详细讨论的那样，我们用识别个别目标方法的开发推出数字图像处理的覆盖范围。
到目前为止，还没有谈到上面图2中关于先验知识及知识库与处理模块之间的交互这部分内容。
关于问题域的知识以知识库的形式被编码装入一个图像处理系统。
这一知识可能如图像细节区域那样简单，在这里，感兴趣的信息被定位，这样，限制性的搜索就被引导到寻找的信息处。
知识库也可能相当复杂，如材料检测问题中所有主要缺陷的相关列表或者图像数据库（该库包含变化检测应用相关区域的高分辨率卫星图像）。
除了引导每一个处理模块的操作，知识库还要控制模块间的交互。
这一特性上面图2中的处理模块和知识库间用双箭头表示。
相反单头箭头连接处理模块。
边缘检测边缘检测是图像处理和计算机视觉中的术语，尤其在特征检测和特征抽取领域，是一种用来识别数字图像亮度骤变点即不连续点的算法。
尽管在任何关于分割的讨论中，点和线检测都是很重要的，但是边缘检测对于灰度级间断的检测是最为普遍的检测方法。
虽然某些文献提过理想的边缘检测步骤，但自然界图像的边缘并不总是理想的阶梯边缘。
相反，它们通常受到一个或多个下面所列因素的影响：1.有限场景深度带来的聚焦模糊；2.非零半径光源产生的阴影带来的半影模糊；3.光滑物体边缘的阴影；4.物体边缘附近的局部镜面反射或者漫反射。
一个典型的边界可能是（例如）一块红色和一块黄色之间的边界；与之相反的是边线，可能是在另外一种不变的背景上的少数不同颜色的点。
在边线的每一边都有一个边缘。
在对数字图像的处理中，边缘检测是一项非常重要的工作。
如果将边缘认为是一定数量点亮度发生变化的地方，那么边缘检测大体上就是计算这个亮度变化的导数。
为简化起见，我们可以先在一维空间分析边缘检测。
在这个例子中，我们的数据是一行不同点亮度的数据。
例如，在下面的1维数据中我们可以直观地说在第4与第5个点之间有一个边界：如果光强度差别比第四个和第五个点之间小，或者说相邻的像素点之间光强度差更高，就不能简单地说相应区域存在边缘。
而且，甚至可以认为这个例子中存在多个边缘。
除非场景中的物体非常简单并且照明条件得到了很好的控制，否则确定一个用来判断两个相邻点之间有多大的亮度变化才算是有边界的阈值，并不是一件容易的事。
实际上，这也是为什么边缘检测不是一个简单问题的原因之一。
有许多用于边缘检测的方法，它们大致可分为两类：基于搜索和基于零交叉.基于搜索的边缘检测方法首先计算边缘强度，通常用一阶导数表示，例如梯度模；然后，用计算估计边缘的局部方向，通常采用梯度的方向，并利用此方向找到局部梯度模的最大值。
基于零交叉的方法找到由图像得到的二阶导数的零交叉点来定位边缘。
通常用拉普拉斯算子或非线性微分方程的零交叉点，我们将在后面的小节中描述.滤波做为边缘检测的预处理通常是必要的，通常采用高斯滤波。
已发表的边缘检测方法应用计算边界强度的度量，这与平滑滤波有本质的不同. 正如许多边缘检测方法依赖于图像梯度的计算，他们用不同种类的滤波器来估计x-方向和y-方向的梯度.一旦我们计算出导数之后，下一步要做的就是给出一个阈值来确定哪里是边缘位置。
阈值越低，能够检测出的边线越多，结果也就越容易受到图片噪声的影响，并且越容易从图像中挑出不相关的特性。
与此相反，一个高的阈值将会遗失细的或者短的线段。
如果边缘阈值应用于正确的的梯度幅度图像，生成的边缘一般会较厚，某些形式的边缘变薄处理是必要的。
然而非最大抑制的边缘检测，边缘曲线的定义十分模糊，边缘像素可能成为边缘多边形通过一个边缘连接（边缘跟踪）的过程。
在一个离散矩阵中，非最大抑制阶梯能够通过一种方法来实现，首先预测一阶导数方向、然后把它近似到45度的倍数、最后在预测的梯度方向比较梯度幅度。
一个常用的这种方法是带有滞后作用的阈值选择。