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Outline. Introduction to Motion Estimation Motion Vector Cost Function Video Codec The Methods for Motion Estimation Conclusion. Introduction to Motion Estimation. Using motion estimation to find the motion vectors Motion Vector

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Outline

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  1. Outline • Introduction to Motion Estimation • Motion Vector • Cost Function • Video Codec • The Methods for Motion Estimation • Conclusion

  2. Introduction to Motion Estimation • Using motion estimation to find the motion vectors • Motion Vector • A 2D point that represents the consistent between the current block and space of previous frame.

  3. Introduction to Motion Estimation • Motion Estimation • Cost function • Sum of Absolute Difference(SAD) • Sum of Squared Difference(SSD)

  4. Introduction to Motion Estimation • Motion Estimation • Cost function • Mean Absolute Error(MAE) • Mean Square Error(MSE)

  5. Outline • Introduction to Motion Estimation • Video Codec • Video encoder • Video decoder • The Methods for Motion Estimation • Conclusion

  6. Video Codec • Video Encoder[1] • Intra-prediction

  7. Video Codec • Video Encoder[1] • Inter-prediction

  8. Video Codec • Video Decoder[1]

  9. Outline • Introduction to Motion Estimation • Video Codec • The Methods for Motion Estimation • Full motion search • Fast motion search • True motion search • Conclusion

  10. The Methods for Motion Estimation • Full motion search (A) Top-to-bottom scan (B) Spiral search[2]

  11. The Methods for Motion Estimation • Fast motion search (A) Three step search[3] (B) Diamond search[4]

  12. The Methods for Motion Estimation • Motion Analysis • Traditional motion estimation • Its goal is found for high compression rate. • There are wrong motion vectors while blocks in several situations. • True motion estimation(TME) • The goal of TME is described the meaningful information of moving object in video sequence.

  13. The Methods for Motion Estimation • The feature of motion vector field(MVF) of TME • The consistency in spatial domain • The dependent in time domain

  14. The Methods for Motion Estimation • True Motion Estimation • Overlapped block-based motion estimation[5] • Take a block that block size bigger than normal block size • 8x8 -> 16x16 • Perform motion estimation after sampling 16x16 block to 8x8 • Post smoothness – Motion vector median filter

  15. The Methods for Motion Estimation • True Motion Estimation • Overlapped block bi-directional motion estimation[6][7] • 8x8 -> 12x12 • Post smoothness – Motion vector median filter

  16. The Methods for Motion Estimation • True Motion Estimation • 3-D recursive search[8] • 1-D recursive search • Small search region • Candidate motion vector • Update motion vector by using recursive research • Update motion vector • Stop condition is necessary

  17. The Methods for Motion Estimation • True Motion Estimation • 3-D recursive search

  18. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • λa = 0.25 • 12 ≦λb ≦ 20

  19. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • The types of motion vector • Unrelated MV • Matched MV

  20. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • The types of motion vector • Unmatched MV • Uncertain MV Frame 39 Frame 40 Repeative Pattern The MVF of Uncertain MV

  21. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • Introduction to reliable motion decision unit • The drawbacks of conventional motion estimation • Can’t classify the reliabilities of MVs • It would make the blocks of consecutive frames produce wrong MVs. • Reliable/Unreliable Motion Vector

  22. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • Introduction to reliable motion decision unit • Reliable motion decision unit based on Early-stop search. • Early-stop search and Early-stop point(ESP) (a)ESP distribution of reliable MV (b)ESP distribution of unreliable MV

  23. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • ESP classification (d)The CDF of ESP of unreliable MV (c)The CDF of ESP of reliable MV

  24. The Methods for Motion Estimation • True motion estimation based on reliable motion decision unit • Smoothness constraint (SC) • The comparison of smoothness constraint and post-smoothness(PS) The MVF of SC The MVF of PS

  25. The Methods for Motion Estimation • The comparison of method • Downsample frame rate 30Hz to 15Hz or 10Hz • Make Bi-directional Motion Compensation Interpolation (BMCI) frames by its before and after frames • Compare BMCI frames with extracted frame

  26. The Methods for Motion Estimation • Experiment result : • Compare PSNR between BMCI frame and extracted frame. • 30Hz -> 15Hz

  27. The Methods for Motion Estimation • Experiment result : • Compare PSNR between BMCI frame and extracted frame. • 30Hz -> 10Hz

  28. The Methods for Motion Estimation • Elapsed time: • 8x8 block, there are 64 subtraction operators and 63 addition operators. • 12x12 block, there are 144 subtraction operators and 143 addition operators.

  29. The Methods for Motion Estimation • Elapsed time:

  30. Conclusion • The motion estimation(ME) of video processing was a popular research in recently decade years. • It must be taken other side-information by ME to apply another applications, such as : object detection, tracking, video stabilization and frame rate up conversion…

  31. Reference • [1] Iain E. G. Richardson, “H.264 and MPEG-4 Video Compression: Video Coding for Next-Generation Multimedia” John Wiley & Sons Inc, 2003 • [2] C. Chok-Kwan, P. Lai-Man, “Normalized Partial Distortion Search Algorithm for Block Motion Estimation,” IEEE Transactions on Circuits and Systems for Video Technology, Vol. 10, No. 3, Apr 2000, pp.417-422. • [3] T. Koga, K. Iinuma, A. Hirano, Y. Iijima, and T. Ishiguro, “Motion compensated interframe coding for video conferencing,” in Proc. NTC81, pp. C9.6.1-9.6.5, New Orleans, LA, Nov./Dec. 1981. • [4] J. Y. Tham, S. Ranganath, M. Ranganath, and A. A. Kassim,   "A novel unrestricted center-biased diamond search algorithm for block motion estimation",  IEEE Trans. Circuits Syst. Video Technol.,  vol. 8,  pp.369 - 377 , 1998. • [5] Taehyeun Ha, Seongjoo Lee and Jaeseok Kim, “Motion Compensated Frame Interpolation by new Block-based Motion Estimation Algorithm,” IEEE Transactions on Consumer Electronics, Volume 50, Issue 2, pp.752-759, May 2004.

  32. Reference • [6]J. Zhai, K. Yu, J. Li, and S. Li, “A low complexity motion compensated frame interpolation method,” in Proc.IEEE ISCAS, May 2005, pp. 23–26. • [7]Ya-Ting Yang, Yi-Shin Tung, and Ja-LingWu, “Quality enhancement of frame rate up-converted video by adaptive frame skip and reliable motion extraction,” IEEE Trans. Circuits Syst. Video Technol., vol. 17, no. 12, pp.1700–1713, Dec. 2007. • [8]G. de Haan, P.W.A.C. Biezen, H. Huijgen, and O.A. Ojo, “True-Motion Estimation with 3-D Recursive Search Block Matching”, IEEE Transactions on Circuits and Systems for Video Technology, VOL.3, NO.5, OCTOBER 1993.

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