Signal Processing Toolkit

Block Matching

Select a block in the current frame, set the search window and search strategy, and see how different block-matching methods locate it in the reference frame.

Current frame: shifted image with the blue block you track.

Reference frame: original image with the best green match inside the dashed search window.

Shifters: move the current frame (Shift X/Y) and the block origin (Block X/Y) to test motion.

Block size Search range ±10 px Search method Frame shift X (current vs. reference) Frame shift Y (current vs. reference) Block X position Block Y position

Current frame

Block to track (blue) in the shifted frame.

Reference frame

Best match (green) found by the selected search method inside the dashed window.

Match details

Offsets are reported as reference − current coordinates (motion vector).

Search method

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Estimated displacement (dx, dy)

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Ground truth (−ShiftX, −ShiftY)

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Error (dx−gt, dy−gt, ‖e‖)

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Search window

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Candidates evaluated

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Best SAD score

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Block matching compares the pixel sum of absolute differences (SAD) for each candidate inside the search region. Faster search strategies evaluate fewer candidates at the cost of potentially missing the global minimum.