Video Tracking G. Medioni, Q. Yu Edwin Lei Maria Pavlovskaia

Goal Track moving objects in a video stream

Linking frames Each frame registered with a satellite image

Detecting Moving Regions A sliding window with the center frame as the reference Register each frame in the window to the reference A region is moving if it differs from the registered frames Moving regions are grouped into tracklets

Tracklet Association Motion Target remains within a reasonable distance between frames Appearance Target has similar color distribution between frames

Tracklet Evolution Temporal moves Change labels Spatial moves Change rectangles at one instant

Merge

Pre-processing Goal Enhance given video before tracking Methods Auto levels Adaptive auto levels

Auto Levels

Histogram of pixel values

Auto Levels Modified histogram

Auto Levels in Video Concerns Algorithm should be fast Do not need to perform histogram computations for each frame Can not treat each channel separately

Adaptive auto levels

Minima cutoffsMaxima cutoffs

Adaptive Auto Levels

Post-processing Identify tracklets that are too short Highlight tracklets of interest Renumber tracklets Display tracklet labels

Highlighting Tracklets Identify tracklets that are too short Highlight tracklets of interest

Renumber tracklets

Displaying Tracklet Labels Goal: intelligently display a label next to every tracklet box

Displaying Tracklet Labels Desired specifications for label placement: – Label must be near corresponding box – Labels must be inside image boundary – Labels should not overlap – Labels should be far from other boxes – Labels should be far from box corners – Labels should not jump from frame to frame – Algorithm must be fast

Final Result

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