计算机专业英语总结

billing, and many other functions. Some of these are not time critical, but many others are, so some, if not all, the CPUs will have to run a real-time operating system,
such as a real-time microkernel. These systems normally break work up into small tasks, each with a known deadline. The scheduler can then run an algorithm
such as nearest deadline next or the rate monotonic algorithm (Liu and Layland,
1973).
The CPU software also defines the nature of the interface that the server presents to the clients (spooling servers and set-top boxes). Two designs are popular.
The first one is a traditional file system, in which the clients can open, read, write, and close files. Other than the complications introduced by the storage hierarchy and real-time considerations, such a server can have a file system modeled after that of UNIX.
缴费单等诸多功能. 有些时候,这些都不重要,但是很多人,所以有的即使不是全部, 中央处理器将开办实时操作系统,诸如实时微. 这些系统工作正常休息整理成小任务,每一个已知的最后期限. 然后办的调度算法等下次或就近截止单调率算法(刘和layland, 1973). CPU的软件还界定性质的接口呈现给客户伺服器(服务器、纱机顶盒). 两个设计都很受欢迎. 一是传统的档案系统,届时客户可以公开,读,写,关闭档案. 除了推出的存储层级并发症和实时考量, 能有这样的服务器文件系统,UNIX的模仿.
The term computer graphics includes almost everything on computers that is not text or sound. Today almost every computer can do some graphics, and people have even come to expect to control their computer through icons and pictures rather than just by typing.
Here in our lab at the Program of Computer Graphics, we think of computer graphics as drawing pictures on computers, also called rendering. The pictures can be photographs, drawings, movies, or simulations -- pictures of things which do not yet exist and maybe could never exist. Or they may be pictures from
places we cannot see directly, such as medical images from inside your body.
We spend much of our time improving the way computer pictures can simulate real world scenes. We want images on computers to not just look more realistic, but also to BE more realistic in their colors, the way objects and rooms are lighted, and the way different materials appear.
The use of computer graphics pervades many diverse fields. Applications range from the production of charts and graphs, to the generation of realistic images for television and motion pictures to the interactive design of mechanical parts [1] .To encompass all these uses, we can adopt a simple definition:
计算机图形学的应用扩展到了许多不同领域，应用的范围从表和图形的产生，到用于电视和动画片的真实图像的生成，到机械零件的交互式设计。

我们采用一个简单的定义来概括所有这些应用：
Computer graphics is concerned with all aspects of using a computer to generate images.
“计算机图形学主要研究采用计算机生成图像的所有方面。

”
We can classify applications of computer graphics into four main areas:
· Display of information
· Design
· Simulation
· User interfaces
我们可以把计算机图形学的应用分作四个主要方面：
·信息显示
·设计
·模拟
·用户界面
Computer Graphics is a subject which is researched how to generate, cope with and handle graphics with computer. The subject introduces basic theoretic knowledge about Computer Graphics. It comprises basic knowledge of Computer Graphics, generation of drawing elements, clipping, Transformation, data structure of graphics, interactive technology and so on. By studying, students should know the framework of graphic system, techniques of software and hardware, application of the computer graphics and current research fields. Some basic concepts, methodology and algorithm must be comprehended. The ability of programming should be enhanced.
计算机图形学是研究如何用计算机生成、处理、显示图形的一门学科。

本课程主要介绍计算机图形学的基础理论知识，主要内容包括：计算机图形学的基本知识、基本图形元素的生成、裁剪、图形变换、图形的数据结构和图形交互技术等等。

通过本课程的学习，使学生了解图形系统的框架及设计的软件、硬件技术，并对与计算机图形学相关的应用及当前的研究热点有一个初步认识；牢固掌握图形学的基本概念、方法与一些基本算法；具有一定的编程能力。

I图像处理操作的层次结构
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[1]．In this way a hierarchical processing scheme is built up as sketched in Fig．12-1．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
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[2]．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 a label 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．
Y ou 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[4]，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. 12-1 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 computer graphics 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．
翻译：
图像处理不是一步就能完成的过程。

可将它分成诸多步骤，必须一个接一个地执行这些步骤，直到从被观察的景物中提取出有用的数据。

依据这种方法，一个层次化的处理方案如图12-1所示，该图给出了图像处理不同阶段的概观。

图像处理首先是以适当的但不一定是光学的采集系统对图像进行采集。

在技术或科学应用中，可以选择一个适当的成像系统。

此外，可以建立照明系统，选择最佳波长范围，以及选择其他方案以便用最好的方法在图像中获取有用的对象特征。

一旦图像被检测到，必须将其变成数字计算机可处理的形式，这个过程称之为数字化。

数字化处理的第一步包含了一系列不同的操作并被称之为图像处理。

如果传感器具有非线性特性，就必须予以校正，同样，图像的亮度和对比度也需要改善。

通常，还需要进行坐标变换以消除在成像时产生的几何畸变。

辐射度校正和几何校正是最基本的像素处理操作。

在图像中，对已知的干扰进行校正也是不可少的，比如由于光学聚焦不准，运动模糊，传感器误差以及图像信号传输误差所引起的干扰。

在此还要涉及图像重构技术，它需要许多间接的成像技术，比如不直接提供图像的X射线断层技术等。

一套完整的处理步骤对于物体的分析和识别是必不可少的。

首先，应该采用适当的过滤技术以便从其他物体和背景中将所感兴趣的物体区分出来。

实质上就是从一幅图像（或者数幅图像）中抽取出一幅或几幅特征图像。

要完成这个任务最基本的工具就是图像处理中所使用的求均值和边缘检测、简单的相邻像素分析，以及复杂的被称为材质描述的模式分析。

物体的一个重要特性就是它的运动性。

检测和确定物体运动性的技术是必不可少的。

随后，该物体必须从背景中分离出来，这就意味着具有同样特性和不同特性的区域必须被识别出来。

这个过程产生出标志图像。

既然已经知道了物体精确的几何形状，就可以抽取诸如平均灰度值、区域、边界以及形成物体的其他参数等更多的信息。

这些参数可用来对物体进行分类，这是许多图像处理应用中至关重要的一步，比如下面一些应用：
在一个显示农业地区的卫星图像中，想要区别出不同的果树，并获取参数以估算出成熟情况并监测害虫情况；
在许多的医学应用中，最基本的问题是检查病理变化，最典型的应用就是染色体畸变分析；λ
印刷体和手写体识别是另一个例子，图像处理一出现，人们就开始对它进行着研究，现在依然困难重重。

λ
人们希望能了解得更多一些，也就是试图理解所读到的内容。

这也是图像处理的最后一个步骤，即理解所观察到的景象。

当我们使用视觉系统时，实际上已或多或少无意识地在执行这个任务。

我们能识别不同的人，可以很轻易地区分出实验室和起居室，可以观察车流以便安全地穿行马路。

我们完成这样的任务而并不了解视觉系统工作的奥秘。

长久以来，图像处理和计算机图形学被看做两个不同的领域。

现在，人们在这两个领域中的知识都有了极大的提高，并可以解决许多复杂的问题。

计算机图形学正在努力使三维景物的计算机图像达到照片级效果。

而图像处理则试图对用照相机实际拍摄的图像进行重构。

从这个意义上讲，图像处理完成的是与计算机图形技术相反的过程。

但从有关物体的形状和特性知识开始（如图12-1的底部所示），向上直到获得一个二维图像要运用图像处理和计算机图形技术，所用到的基本知识都是一样的。

我们需要了解物体和照明之间的相互关系，三维景物是如何投影到图像平面上的等有关知识。

图像处理和计算机图形工作站之间仍然有一些不同之处。

但我们应该看到，一旦较好地理解了计算机图形技术和图像处理之间的相似性和相互关系，并开发出了适当的硬件系统，一些既可处理计算机图形，又可完成图像处理任务的通用工作站就会出现。

多媒体的出现，即文字、图像、声音和电影的综合，将进一步加速计算机图形学和图像处理的统一。

图形学
term often refers to three-dimensional computer graphics, it also encompasses two-dimensional graphics and image processing. Computer graphics is often differentiated from the field of visualization, although the two have many similarities.
A broad classification of major subfields in computer graphics might be:
1. Geometry: studies ways to represent and process surfaces
2. Animation: studies with ways to represent and manipulate motion
3. Rendering: studies algorithms to reproduce light transport
4. Imaging: studies image acquisition or image editing
Contents
[hide]
1Definition
2Geometry
2.1Subfields
3Animation
3.1Subfields
4Rendering
4.1Transport
4.2Scattering
4.3Other subfields
5History
6Applications
7Connected studies
8Computer graphics research groups
8.1Research
8.1.1University Groups
8.1.2Applied Research Centres
8.2Industry
9Notable researchers in computer graphics
10See also
11References
12External links
Definition
Computer graphics broadly studies the manipulation of visual and geometric information using computational techniques. Computer graphics as an academic discipline focuses on the mathematical and computational foundations of image generation and processing rather than purely aesthetic issues
Geometry
The subfield of geometry studies the representation of three-dimensional objects in a discrete digital setting. Because the appearance of an object depends largely on the exterior of the object, boundary representations are most common in computer graphics. Two dimensional surfaces are a good analogy for the objects most often used in graphics, though quite often these objects are non-manifold. Since surfaces are not finite, a discrete digital approximation is required: polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have been gaining some popularity in recent years (see the Symposium on Point-Based Graphics, for instance). These representations are Lagrangian, meaning the spatial locations of the samples are independent. In recent years, however, Eulerian surface descriptions (i.e., where spatial samples are fixed) such as level sets have been developed into a useful representation for deforming surfaces which undergo many topological changes (with fluids being the most notable example[1]).
Subfields
Constructive solid geometry - Process by which complicated objects are modelled with implicit geometric objects and boolean operations Discrete differential geometry - a nascent field which defines geometric quantities for the discrete surfaces used in computer
graphics.[2]
Digital geometry processing - surface reconstruction, simplification, fairing, mesh repair, parameterization, remeshing, mesh generation, surface compression, and surface editing all fall under this heading.[3][4][5] Point-based graphics - a recent field which focuses on points as the fundamental representation of surfaces.
Subdivision surfaces
Out-of-core mesh processing - another recent field which focuses on mesh datasets that do not fit in main memory.
The subfield of animation studies descriptions for surfaces (and other phenomena) that move or deform over time. Historically most interest in this area has been focused on parametric and data-driven models, but in recent years physical simulation has experienced a renaissance due to the growing computational capacity of modern machines.
[edit] Subfields
Performance capture
Character animation
Physical simulation (e.g. cloth modeling, animation of fluid dynamics, etc.)
[edit] Rendering
1. scattering - how light interacts with the surface at a given point
2. shading - how material properties vary across the surface
[edit] Research
The number of computer science institutions working in computer graphics research has grown rapidly over the past two decades.
Click show for a partial list of research institutions notably involved in graphics
research [show]
[edit] Industry
Industrial labs doing "blue sky" graphics research include:
Adobe Advanced T echnology Labs
MERL
Microsoft Research - Graphics
NVIDIA Research
Major film studios notable for graphics research include:
ILM
PDI/Dreamworks Animation
Pixar。