Video Tracking

G. Medioni, Q. Yu

Edwin LeiMaria 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

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

Adaptive auto levels

Adaptive auto levels

Minima cutoffs Maxima 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

Thanks!