数字图像处理ppt课件（冈萨雷斯）.ppt

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1、Digital Image Processing,Prof.Dr.Chen Hui School of ISE,Shandong University email:,Lecture 2,Introduction,Background Digital Image Representation Fundamental Steps In Image Processing System Elements of Digital Image Processing System Further Readings One Picture is worth more than a thousand words.

2、,Chapter 1 no.1,Background,Applications:Improvement of pictorial information for human interpretation.Processing of scene data for storage,transmission,and representation for autonomous machine perception.Scope definitionOrigins State of the artPrincipalsOverview of system,Chapter 1 no.2,What are DI

3、P and scope?(read book),Digital Image:discrete both in space(x,y)and amplitude fProcessing by digital computerPicture elements,image element,pels,pixels Not limited to visual band:wide&variety field of applicationsNo general agreement on the scope of processing,analysis,vision.Input&output,emulate h

4、uman vision(AI).No clear-cut boundaries.I/O images,extract attributes,recognizing objects.Such as analysis of text.,Chapter 1 no.3,History,Early 1920s,Bartlane cable picture transmission system.(special character,515 gray level).Middle 1960s,space shuttle,aerial and satellite imagery.(large-scale co

5、mputer&space programDIP concepts).Others,medical image(x-ray,MRI,CT.),geography,archeology,astronomy,physics(high-energy plasmas,electron microscope).Machine perception:character recognition,industrial machine vision,military recognizance,matching fingerprints,etc.,Chapter 1 no.4,History(cont.1),Cha

6、pter 1 no.5,Digital images,History(cont.2),Chapter 1 no.6,Digital images,History(cont.3),Chapter 1 no.7,Digital image processed by computer,Examples,Chapter 1 no.8,Gamma ray,Examples(cont.1),Chapter 1 no.8,X ray,Example(cont.2),Chapter 1 no.9,Visible&Infrared,Example(cont.4),Chapter 1 no.10,Infrared

7、,Examples(cont.5),Chapter 1 no.11,Radio band,Examples(cont.6),Chapter 1 no.12,Ultrasound,Examples(cont.7),Chapter 1 no.13,Visual spectrum,Digital Image Representation,Definition:monochrome image(image),a two-dimensional light intensity function f(x,y),point(x,y)spatial coordinates,f brightness value

8、 of the point.Digital Image:Discretized both in spatial coordinates and brightness(matrix,elements,pixels).Image size and the number of gray level are advantages to be chosen as integer power of 2.(512*512,128!),Chapter 1 no.14,Digital Image Representation(cont.),Chapter 1 no.15,Digital Image Repres

9、entation(cont.),Chapter 1 no.15,Fundamental Steps In Image Processing System,Image acquisition(image sensor&AD converter)camera,scanner.Preprocessing(improve image)enhancing contrast,removing noiseSegmentation partition an input image into its constituent part,output raw pixel data either of boundar

10、y or region.Representation and description(descriptors,feature selection)Recognition and interpretation assign a label to an object,assign meaning to recognized objects.an example:automatic reading of the address on piece of mail.,Chapter 1 no.16,Elements of Digital Image Processing System,Chapter 1

11、 no.17,Further Reading,Slides available as pdf filesR.C.Gonzalez,R.E.Woods,“Digital Image Processing”,2nd edition,Prentice-Hall,2002,Pratt,W.K.,Digital Image Processing,3rd ed.,John Wiley&Sons,NY.,2001.IEEE Transactions on Image Processing.IEEE Transactions on Pattern Analysis and Machine Intelligen

12、ce.Computer Vision and Image Understanding.IEEE Transactions on Signal Processing.IEEE Transactions on Medical Imaging.,Chapter 1 no.18,Elements of Visual Perception,Structure of Human Eye,Chapter 2 Elements of visual perception no.1,Image Formation in the Eye,2.55mm,Elements of visual perception no

13、.2,Brightness Adaptation,Cannot operate such a range simultaneously.Rather,by changes in its overall sensitivity.,Elements of visual perception no.3,Brightness Discrimination Experiment,Brightness discrimination is poor at low levels of illumination.,Elements of visual perception no.4,Mach Band Patt

14、ern,Visual system tends to undershoot or overshoot around the boundary of regions of different intensities.,Elements of visual perception no.5,Simultaneous Contrast,A regions perceived brightness does not depend simply on its intensity.,Elements of visual perception no.6,Optical Illusions,Fill in non_existence/wrongly perceive geometry.,Elements of visual p erception no.7,Reading Questions,What is Sampling?What is Quantization?How many samples are required for a good approximation?How many gray levels are required for a good approximation?,