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Computer Vision – Overview Hanyang University Jong-Il Park.

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Presentation on theme: "Computer Vision – Overview Hanyang University Jong-Il Park."— Presentation transcript:

1 Computer Vision – Overview Hanyang University Jong-Il Park

2 Department of Computer Science and Engineering, Hanyang University Digital Image Processing Sampling & Quantization Image Enhancement Image Restoration Image Coding( or Image Data Compression) Image Understanding( or Computer Vision)

3 Department of Computer Science and Engineering, Hanyang University Image formation

4 Department of Computer Science and Engineering, Hanyang University Sampling & Quantization

5 Department of Computer Science and Engineering, Hanyang University

6 Department of Computer Science and Engineering, Hanyang University Subsampling & aliasing aliasing

7 Department of Computer Science and Engineering, Hanyang University Sub-Nyquist sampling H ½, v ½ Org. Circular Zone Plate aliasing

8 Department of Computer Science and Engineering, Hanyang University Image Enhancement Goal  to accentuate certain image features for subsequent analysis or for image display Input : imageOutput : image

9 Department of Computer Science and Engineering, Hanyang University

10 Department of Computer Science and Engineering, Hanyang University

11 Department of Computer Science and Engineering, Hanyang University Image Enhancement Techniques  contrast/edge enhancement  histogram equalization  pseudo coloring  noise filtering  edge sharpening  smoothing Applications  processing of remote-sensed image via satellite  radar, SAR, Ultrasonic image processing

12 Department of Computer Science and Engineering, Hanyang University Image Restoration Goal  to remove or minimize known/unknown degradations in image

13 Department of Computer Science and Engineering, Hanyang University

14 Department of Computer Science and Engineering, Hanyang University Blur model  estimate or recover f(x,y) from g(x,y)  deconvolution problem

15 Department of Computer Science and Engineering, Hanyang University Enhancement by integration

16 Department of Computer Science and Engineering, Hanyang University Image Restoration Techniques  deblurring  noise filtering  correction of geometric distortion  inverse filtering  Least mean square(Wiener) filtering Applications  remote-sensed image processing  noise cancellation

17 Department of Computer Science and Engineering, Hanyang University Image Data Compression Goal  to reduce the amount of data required to represent images Input : imageOutput : bit-stream data “010100101100110101001....” moving image: 1,000  1,000  8(bits/sample)  3  30 frame/sec = 72  10 7 bit/sec

18 Department of Computer Science and Engineering, Hanyang University 2-D Image Compression, JPEG (a) 27.9 dB at 0.125 bpp(b) 31.5 dB at 0.25 bpp(c) 34.8 dB at 0.5 bpp Image quality by JPEG

19 Department of Computer Science and Engineering, Hanyang University

20 Department of Computer Science and Engineering, Hanyang University

21 Department of Computer Science and Engineering, Hanyang University 3D Mesh Compression Original ‘Bunny’ 12 bpc8 bpc10 bpc Model# of Vertex # of Triangle Original (byte) Compressed (byte) 12 bpc10 bpc8 bpc Bunny34835694732,879,78657,95237,64224,842 Compression ratio50 : 177 : 1116 : 1

22 Department of Computer Science and Engineering, Hanyang University Image Data Compression Techniques  Error-free coding( or lossless coding)  Lossy compression  Image Compression Standard  JPEG, H.261, H.263, MPEG-1,2,4 etc Applications  Transmission  teleconferencing,TV system, remote sensing via satellite  Storage  VOD(video on demand), Video CD, DVD(digital video disk), medical imaging, educational and business documents

23 Department of Computer Science and Engineering, Hanyang University Image Coding Standards

24 Department of Computer Science and Engineering, Hanyang University MPEG MPEG-1  1992  Video CD  Includes Audio Layer III (MP3) MPEG-4  Part 1: 1998  Part 2: 1999 (addition still under development)  Audio visual object  Mobile telephony (IMT-2000)  Interactivity  Content –Based Interactivity

25 Department of Computer Science and Engineering, Hanyang University MPEG-7  2001 (addition still under development)  Content Description Interface  Metadata language and schemes for search & retrieval

26 Department of Computer Science and Engineering, Hanyang University Content-based Image Retrieval Image retrieval  Find similar images from image database Used features  Color  Texture  Shape Query Retrieved

27 Department of Computer Science and Engineering, Hanyang University Query Image Image Data List Retrieval Results Texture Option

28 Department of Computer Science and Engineering, Hanyang University Video retrieval  Scene change detection and key frame extraction  Extracted key frame from a movie clip Content-based Video Retrieval

29 Department of Computer Science and Engineering, Hanyang University Video retrieval  Automatic indexing  Index from a news sequence Content-based Video Retrieval

30 Department of Computer Science and Engineering, Hanyang University Media Framework Tech. MPEG-21  All electronic creation, delivery and trade of digital multimedia content  Transparent usage of various content types on various devices connected through various network

31 Department of Computer Science and Engineering, Hanyang University Watermarking the process of embedding information into a host signal without changing perceived characteristics of the host

32 Department of Computer Science and Engineering, Hanyang University Image Understanding Goal  to interpret or describe the meaning contained in the image Input : imageOutput : interpretation(description) “KAISION” “circle”

33 Department of Computer Science and Engineering, Hanyang University

34 Department of Computer Science and Engineering, Hanyang University

35 Department of Computer Science and Engineering, Hanyang University Stereo Vision (disparity map) 기준 영상 ( 좌 ) 기준 영상 ( 우 ) 변위 참 값 ( 붉은색 : 가리워짐 ) 구한 변위 지도 ( 검은색 : 가리워짐 )

36 Department of Computer Science and Engineering, Hanyang University ModelModel image Input scene Scene matching result Scene Matching (1)

37 Department of Computer Science and Engineering, Hanyang University Model Input imageEdge image Scene matching result Scene Matching (2)

38 Department of Computer Science and Engineering, Hanyang University – 크기, 반지름 Fruit Classifier Apple Orange Water Mellon

39 Department of Computer Science and Engineering, Hanyang University – color

40 Department of Computer Science and Engineering, Hanyang University Edge Detection

41 Department of Computer Science and Engineering, Hanyang University Segmentation (a) Aerial Original Image(b) Segmented Image

42 Department of Computer Science and Engineering, Hanyang University

43 Department of Computer Science and Engineering, Hanyang University There are a lot of interesting topics to explore in image processing and computer vision.


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