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1The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringEESM 532 Image and Video Signal ProcessingLecture 1:What is digital image processing? Examples and ApplicationsIntroductionWhat is Digital Image/Video Processing (DIP/DVP)? Why is it important?What knowledge do you need in order to take this course? What is going to be covered in this course? What textbooks are we going to use? Where to obtain additional information?Course assessment3The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringWhat is Digital Image/Video Processing?Definition of Image : a 2-D function f (x , y ) Definition of Video : a 3-D function f (x , y , t )Digital image/video:f , x , y , t ,are all finite , discrete quantitiesDigital image/video processing:involves the use of digital computerComputers in Image and Video ProcessingSpecialized digitization hardware, front-end noise averaging, etc.5 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringImportance of DIP/DVPVisual perception is the most important source of information for human being–See it once is more than hear it hundred times(wider bandwidth than any other senses)Spatial structure information in the perceptionNaturally, capturing such information on a computer will yield many important applicationsRelations to other fields:–Signal processing–Image analysis/image understanding/computer visionExamples of DIPSpace Images (One of earliest DIP applications)First picture of moon by USspacecraft (1964)7The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringMedical Imaging (X -Ray)X -RayHead CT ScanTechnique:•Fire electrons between a heated cathode and an anode in a vacuum tube. •X-rays released when electrons meet a nucleus.•Interesting fact: X-rays discovered in 1895 –Nobel Prize in Physics.Examples of DIPMedical Imaging (Nuclear –Gamma Ray)Bone Scan PETTechnique:•Inject patient with radioactive isotope •Measure gamma ray emissions9The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringMedical Imaging (Ultrasound)Technique:•Ultrasound system transmits high frequency sound pulses into body•Sound waves are reflected by tissues in the body, which are measured by a probe• A machine calculates distance from probe to reflected tissue using speed of sound in tissue and time of return •Results displayed on a screenRemote SensingSatellite image of Hurricane Katrina11 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringFingerprintidentification andrecognitionLaw EnforcementFace detection and recognition13 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringManufacturingAutomated productinspection andquality control Defects15 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringMining and Robotics (Machine Vision)Stereo ImagingSource: Fast and Robust Stereo Matching Algorithmsfor Mining Automation, J. Banks, M. Bennamoun, andP. Corke, Digital Signal Processing,pp. 139-148, 1999.Left CameraRight CameraWhy Process Images/Videos?Enhancement and restoration–Remove artifacts and scratches from old photos/videos–Improve contrast and correct blurry images/videosTransmission and storage–Images/video from overseas via internet, or from remove planet, transmission over mobile phone, etcInformation analysis and automatic recognition–Providing “human vision”to machinesSecurity and rights protection–Encryption and watermarking17The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringWhy Digital?Perfect reproduction without degradation (in theory)Convenient and powerful computer -aided processing–Can perform sophisticated processing through hardware or software (as we will see)Easy storage and transmission–Huge capacity of DVDs for storing movies, photos, etc –Advanced digital compression–Allows for digital multiplexing and error protection for transmission…Useful Knowledge in this CourseLinear Algebra: Vectors and matricesProbability: basic distributions, random variablesSignals and Systems: Transforms, linear systems,filtering, samplingDigital Signal ProcessingIf you are not familiar with above knowledge, many useful tools and tutorials at:/root_files_V3/tutorials.htm19The Hong Kong University of Science and Technology Department of Electronic and Computer EngineeringCoverage of This CourseImage and video formationImage enhancement and restorationColor perception and applications to image/video processing Image and video compression Motion estimationImage and video standardsExtra topics:–Image and video communications –Morphological operations –…Example of Image EnhancementOriginal imageImage after contrast enhancement21 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringExample of Image Restoration Original ImageImage afterrestorationFourier Transformof Original ImageFourier Transformafter restoration22 The Hong Kong University of Science and TechnologyDepartment of Electronic and Computer EngineeringExample of Image CompressionColor image of 600x800 pixels–Without compression:600*800*24 bits/pixel = 1.44 MB–After JPEG compression:Approx 89 KBCompression ratio: 16:1Video: 720x480 per frame,30 frames/sec, 24 bits/pixel–Raw video without compression:Approx 243 M bits/sec–DVD (after compression):Approx 5 M bits/sec–Compression ratio: 48:123The Hong Kong University of Science and Technology Department of Electronic and Computer Engineering DIP System Example: Face Recognition Refer to Poster。