1. MOTION ESTIMATION IMPLEMENTATION IN RECONFIGURABLE PLATFORMS

2. OUTLINE MOTION ESTIMATION BLOCK MATCHING MOTION ESTIMATION
EXISTING MOTION ESTIMATION IMPLEMENTATIONS
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3. MOTION ESTIMATION (ME)
Video compression kernel based on high correlation between frames in a video sequence
Operation that estimates the motion vectors of moving objects in sequence
Most computationally complex and power intensive operation in video compression
Objects can have complex shapes and motion (rotation, camera zoom etc.)
Block matching ME is an efficient approximation
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4. BLOCK MATCHING ME Συντεταγμένες διανύσματος κίνησης: (x + u), (y + v)
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5. BLOCK MATCHING ADVANTAGES DISADVANTAGES
simple
straightforward
very efficient
DISADVANTAGES
Causes block artifacts
Can still be computationally intensive for large frame sizes
Efficient search strategy is required
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6. SEARCH ALGORITHMS: FULL SEARCH
Exhaustive (raster scan)
Optimum result
Most computationally intensive
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7. SEARCH ALGORITHMS: SPIRAL SEARCH
Spiral scan with early termination
Worst case equal to FS
Can be trapped in a local minimum
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8. SEARCH ALGORITHMS: THREE STEP SEARCH
A search algorithm based on a coarse original search using 9 points
The search is refined in two subsequent searches around the best match found in each step
Total number of search points: 9 + 2x18 = 25
Can be trapped in a local minimum
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9. MATCHING CRITERION
Second most important implementation factor after the search strategy
Must be as computationally simple as possible yet provide accurate evaluation of candidate block
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10. POSSIBLE SEARCH CRITERIA
Mean Absolute Error
Mean Square Error
Sum of Square Differences
Sum of Absolute Differences
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