Accurate segmentation of moving objects and their shadows via brightness ratios and movement patterns

We present a two-stage method to accurately segment single or multiple moving objects and their shadows, especially when the moving objects have similar chromaticity and intensity to their shadows or when they are immersed in the shadows of other moving objects. Our algorithm first detects potential shadows via brightness ratios at each motion region, which is already separated from the background of an image sequence. Movement patterns are then applied to optimize the regions of moving objects and their shadows. We conducted experiments using our captured image sequences and public videos of Highway I and II to verify our method. The results demonstrate the method's efficiency quantitatively and qualitatively in comparison with ground truth and several advanced methods.