Color Histogram

A statistical summary of the distribution of colour values across the pixels of an image or image region, often computed in a perceptual colour space such as Lab. In assistive computer-vision systems for blind users, colour histograms are used to re-identify and track a specific target pedestrian (such as the last person in a queue) across frames, measuring similarity between frames using distances like the Bhattacharyya distance. Histogram-based tracking is more robust to partial occlusion and changes in pose than bounding-box overlap alone, which matters when a blind user's phone loses sight of the target in a crowded scene.