1. JPEG2000 Yeh Po-Yin Lien Shao-Chieh Yang Yi-Lun

2. Outline Introduction Features Flow chart Discrete wavelet transform EBCOT ROI coding Comparison of ROI coding algorithms Conclusion Reference

3. Introduction The Joint Photographic Experts Group Intended to create a new image coding system for different types of still images. Compliment and not to replace the current JPEG standards

4. Features Superior low bit-rate performance Below 0.25bpp for highly detailed gray- scale images Lossless and lossy compression Progressive transmission by pixel accuracy and resolution Reconstruct images with increasing pixel accuracy

5. Features Region-of-Interest coding More important parts be coded and transmitted with better quality and less distortion Random codestream access and processing Robustness to bit-error Open architecture

6. Features Context-based description Image archival, indexing and searching Protective image security Watermarking, labeling, stamping and encryption Continuous-tone and bi-level compression

7. Flow chart tile DWTQ subband tile code block code block code block code block subband Input Image Desired ROI contourWavelet mask generation Differential Chain Coding (DCC) Bit Plane Coding Apply ROI bitplane shift Binary Arithmetic Coding (MQ) Output bit stream code block File formatting and Layer formation EBCOT

8. Discrete Wavelet Transform Convolution-based Lifting-based 9-tap/7-tap Filter - lossy 5-tap/3-tap Filter – lossless Tap - number of coefficients

9. Lifting-based DWT

10. Multi-level DWT

12. Embedded block coding with optimized truncation (EBCOT) Block coding and bitstream generation Postcompression rate distortion (PCRD) optimization Replaced by the MQ coder to avoid divisions Layer formation and representation

13. EBCOT – block coding Each block been coded independently

14. EBCOT – rate distortion Minimize the overall distortion,subject to the bit-rate constraint. where is the distortion from code block B i having truncation point n i

15. EBCOT Layered Bit-Stream Formation

16. MQ coder Recursively subdivide the 0-1 interval Base on the conditional probability of the input symbols Input symbols More Probable Symbols (MPS) Less Probable Symbols (LPS)

17. Region-of-Interest Coding Particular regions of the image may be coded with better quality

18. ROI Mask Generation In wavelet domain

19. ROI Bitplane shift Generic scaling based method Scaling based arbitrary shape ROI coding method Maxshift method Bitplane-by-Bitplane Shift method Generalized Bitplane-by-Bitplane Shift method Partial Significant Bitplanes Shift method

20. Generic scaling based Control the relative importance between ROIs and BG Adjust the scaling values (s) Support multiple ROIs Most significant bitplane Least significant bitplane ROI BG s

21. Generic scaling based Not convenient to deal with different wavelet subbands in different ways Needs to encode and transmit the shape information of the ROIs Support rectangle and ellipse Shape coding will consume a large number of bits if arbitrary ROI shapes are desired

22. Scaling based arbitrary shape ROI coding method Improved Generic Scaling based method to support arbitrary shape ROI Use Differential Chain Coding (DCC) to code the ROI contour information

23. Differential chain coding (DCC) Code the ROI contour information Begin from a seed point located at the top left-most contour pixel Directions ( Huffman coded ): Same direction ( SD = 0 ) Different direction: Counter-clockwise ( DDCCW = 11 ) Clockwise ( DDCW = 10 )

24. Maxshift Can have arbitrary shaped ROI Choose different bitrates for the ROI and for the BG Give similar results to general scaling method No need of shape information to the decoder Most significant bitplane Least significant bitplane ROI BG

25. Maxshift Cannot support multiple ROIs No priority difference Cannot control the relative importance between ROIs and BG

26. Circularly shaped ROI The quality of ROI remains while reducing bit rate (a) 0.4bpp (b) 0.5bpp (c) 0.6bpp (d) 0.7bpp

27. Take the advantages of Generic scaling based and Maxshift methods Able to control the relative importance between ROIs and BG No need of shape information to the decoder Cannot support multiple ROIs Bitplane-by-Bitplane shift Most significant bitplane Least significant bitplane ROI BG s 1 = 6s 2 = 4

28. Comparison 24bpp RGB image decoded at 0.8bpp using (left) Maxshift method [s = 12], and (right) the BbBShift method [s 1 = 6, s 2 = 6]

29. Generalized Bitplane-by-Bitplane Shift Transmit BP mask instead of scaling values Provide better quality at BG without visual difference at ROI (compared with Maxshift method) Cannot support multiple ROIs Most significant bitplane Least significant bitplane ROI BG 000001110111111 BP Mask 0000 1

30. Comparison

31. Improved GBbBshift to support multiple ROIs Coded with different quality according to their priorities in an image Single ROI Partial Significant Bitplane shift Most significant bitplane Least significant bitplane ROI BG ss

32. Comparison (a) 0.5bpp using Maxshift [s = 12] (b) 0.5bpp using PSBShift [s = 10]

33. Partial Significant Bitplane shift Multiple ROIs Most significant bitplane Least significant bitplane ROI - 1 BG ROI - 2 ROI - 3 s 1 = 8 s 2 = 6 s 3 = 4 S = Max(s 1, s 2, s 3 )

34. Multiple ROI coding results PSNR Decoding bit rate (bpp)

35. Conclusion JPEG2000 is the new standard for still image compression Provides a wide range of functionalities for still image applications Internet Color facsimile Printing Scanning Digital photography Remote sensing Mobile applications Medical imagery Digital library E-commerce

36. Comparative result JPEG2000 is indeed superior to existing still image compression standards

37. References C. Christopoulos, A. Skodras, and T. Ebrahimi, “The JPEG2000 still image coding system: An overview,” IEEE Trans. Consum. Electron., vol. 49, p1103-1124, Nov. 2000 K. Andra, C. Chakrabarti, T. Acharya, “A High-Performance JPEG2000 Architecture,” IEEE Trans. Vol. 13, No 3, p209-218, March 2003 L. Liu, G. Fan, “A New JPEG2000 Region-of-Interest Image Coding Method: Partial Significant Bitplanes Shift,” IEEE Signal Processing Letters, Vol. 10, No. 2, p35-38, Feb. 2003 Chung-Jr Lian, Kuan-Fu Chen, Hong-Hui Chen, Lian-Gee Chen, “Lifting Based Discrete Wavelet Transform Architecture for JPEG2000,” IEEE, 0- 7803-6685-9, p445-448, 2001 M. Subedar, L. Karam, G. Abousleman, “An Embedded Scaling-Based Arbitrary Shape Region-of-Interest Coding Method for JPEG2000,” 0-7803- 8484-9, p681-684, 2004 K. Varma, A. Bell, “JPEG2000-Choices and Tradeoffs for Encoders,” IEEE Signal Processing Magazine, p70-75, Nov. 2004 Z. Wang, A.Bovik, “Bitplane-by-Bitplane Shift (BbBShift)- A Suggestion for JPEG2000 Region of Interest Image Coding,” IEEE Signal Processing Letters, Vol. p, No. 5, p160-162, May. 2002 Z. Wang, S. Banerjee, B. Evans, A. Bovik, “Generalized Bitplane-by-Bitplane Shift Method for JPEG2000 ROI Coding,” IEEE ICIP, p81-84, 2002 王聰智, “ 資料壓縮, 專題報告 – JPEG2000,” http://140.116.72.203/pdf/course/Reports/JPEG_2000.pdf

38. Q&A

39. State information bits Significance Refinement Sign

40. Coding method Zero coding (ZC) Sign coding (SC) Run length coding (RLC) Magnitude refinement coding (MRC)

41. Coding passes Significance propagation pass Magnitude refinement pass Cleanup pass