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Video Communication Final Project =Motion Estimation=

Video Communication Final Project =Motion Estimation=. Instructor : Chia -Hung Yeh Student : Po- jiun Lin (Neil) Date : 2011.1.13. Introduction. Motion Estimation is an important issue in any video processing system, especially in the video compression.

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Video Communication Final Project =Motion Estimation=

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  1. Video Communication Final Project=Motion Estimation= Instructor : Chia-Hung Yeh Student : Po-jiun Lin (Neil) Date : 2011.1.13

  2. Introduction • Motion Estimation is an important issue in any video processing system, especially in the video compression. • Full search is a well-known algorithm to obtain the motion estimation efficiently, but it costs lots of computational complexity and search time. • Consequently, more and more fast search algorithm are proposed, such as TSS, NTSS, DS, 2-d logarithmic search, 4SS, Orthogonal search and Cross search, etc.

  3. Some statistical properties of the motion estimation • There are nearly 80% motion vectors surrounding the center of the zero motion vector, which radius is two pixels. • Therefore, the motion vectors of the macroblock are mainly distributed in this circle. • Most of the macroblocks are motionless. • Most of the macroblocks are distributed in the horizontal and vertical direction.

  4. Motive • From the above properties, I design my algorithm to find the central 9 points in the first. Because I consider most of the motion vector is near the centre. • In order to get the balance between motion and motionless image, I search the larger range in the second stage by double the step size. • Finally, I can find the whole search point by enlarging and reducing the step size.

  5. My Algorithm-Enlarge first and reduce later • Step 1 : Pick an initial step size, all the nine blocks around the centre are chosen for the search. If the SAD point calculated is located at the center position, then the algorithm stops; otherwise, go to step 2. • Step 2 : If the position of best match is around the centre, then the centre is moved to the point with the minimum distortion and double the step size. • Step 3 : If the position of best match is around the centre, repeat step 2; otherwise, halve the step size. • Step 4 : Halve the step size. • Step 5 : Halve the step size.

  6. Proposed method – Case 1 Blocks chosen for the First Stage Second Stage Third Stage Fourth Stage Fifth Stage

  7. Proposed method – Case 2 Blocks chosen for the First Stage Second Stage Third Stage

  8. Proposed method – Case 3 Blocks chosen for the First Stage

  9. Simulation environment • Akiyo and Football QCIF sequence • Search region from -7 to 7 • Macroblock size 16x16 (pixels) • Compare my method with Full Search, Three Step Search and Diamond Search.

  10. Demo - Akiyo Original Akio Full Search Three Step Search My method

  11. Demo - Football Original Akio Full Search Three Step Search My method

  12. Analysis – PSNR Frames

  13. Analysis – PSNR Frames

  14. Analysis – Average PSNR

  15. Analysis – Search point Best case : The best match search point is in the centre. Worst case : The search point is in the edge.

  16. Analysis – Execution time

  17. Thanks a lot!Q & A

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