1 / 22

Adaptive Edge-Based Side-Match Finite-State Classified Vector Quantization with Quadtree Map

Adaptive Edge-Based Side-Match Finite-State Classified Vector Quantization with Quadtree Map. IEEE transactions on image processing. VOL. 5, NO. 2, FREBRARY 1996 Authors Ruey-Feng Chang( 張瑞峰 ), CS, CCU Wei-Ming Chen( 陳偉銘 ), CS, CCU. Outline. Introduction of Vector Quantization (VQ)

aviva
Download Presentation

Adaptive Edge-Based Side-Match Finite-State Classified Vector Quantization with Quadtree Map

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Adaptive Edge-Based Side-Match Finite-State Classified Vector Quantization with Quadtree Map IEEE transactions on image processing. VOL. 5, NO. 2, FREBRARY 1996 Authors Ruey-Feng Chang(張瑞峰), CS, CCU Wei-Ming Chen(陳偉銘), CS, CCU

  2. Outline • Introduction of Vector Quantization (VQ) • Basic VQ techniques • Adaptive edge-based side-match • Simulation results • Conclusion

  3. Introduction of Vector Quantization (1/2) • Efficient scheme for image compression • Component • Codebooks • Generated by using the iterative clustering algorithm • Encoder • Image is first partitioned into non-overlapping rectangular blocks (vectors) • Each vector is quantized (indexed) to the closest codeword in the codebook • Decoder • Select the corresponding codeword in the codebook via indexes

  4. Clustering algorithm Partition image to NxN blocks (vectors) Find the closet codeword and index for each vector Re-constructing image Find the corresponding codeword via indexes Training image set Target image Codebook Yi, i= 1, …, Nc Encoder side Decoder side

  5. Introduction of Vector Quantization (2/2) • What is closest codeword • Small Euclidean distance • How to generate codebooks • Cluster algorithm • K-means • Linde-Buzo-Gray (LBG) • …

  6. Basic VQ techniquesClassified Vector Quantization (CVQ) • Features • Multiple codebooks for specified features of blocks • Advantage • Reduce search time • Disadvantage • Extra bits needed

  7. Basic VQ techniquesFinite-State Vector Quantization (FSVQ) • Features • Similar to CVQ, but the used codebook is decided by current codebook and current codeword • Advantage • Reduce search space • Extra bits aren’t needed • Disadvantage • Derailment

  8. Basic VQ techniquesSide-Match Vector Quantization (SMVQ) (1/2) • Features • A class of FSVQ, but use the side of upper and left neighboring blocks to generate the state codebook • Advantage • Reduce search space • Smoother • Disadvantage • Derailment

  9. Basic VQ techniquesSide-Match Vector Quantization (SMVQ) (2/2)

  10. Adaptive edge-based side-match • Edge Detection • Sobel Filter • Classification • Non Edge Block (SMVQ) • Edge Block (CVQ,SMVQ)

  11. Adaptive edge-based side-matchSobel Filter (1/2) • Sobel Filter can increase the high frequency part of image. • Formula • Gradient : • Θ : threshold for checking if the edge occur

  12. Image region Mask used to compute Gx Mask used to compute Gy Adaptive edge-based side-matchSobel Filter (2/2) • Sobel operator • Gy = (z3 + 2z6 + z9) – (z1 + 2z4 + z7) • Gx = (z7 + 2z8 + z9) – (z1 + 2z2 + z3)

  13. Adaptive edge-based side-matchQuadtree Map • Problem • Each vector need one more bit to determine its class • For example, in a 512 X 512 image with 4 X 4 block size, 16386 bits must be transmitted to the decoder • Solution • Quadtree map QTC=1-0011-0001-0011

  14. Adaptive edge-based side-matchEdge Block(CVQ) • Nonedge blocks encode first. • Original SMVQ • The edge blocks are classified into 16 subclasses, according to the neighboring blocks which are edge or nonedge.

  15. Adaptive edge-based side-matchEncode

  16. Adaptive edge-based side-matchDecode

  17. Simulation results (1/5) • Contribution • Higher quality with the same bit rate • Codebooks size are variable • Test arguments • 256 gray level image • Image size : 512 x 512 • Vector size : 4 x 4 • Test criterion

  18. Simulation results (2/5)

  19. Simulation results (3/5)

  20. Simulation results (4/5)

  21. Simulation results (5/5)

  22. Conclusion • The classified FSVQ combine the advantages of CVQ and SMVQ • The system complexity is higher

More Related