Separation and contrast enhancement of overlapping cast shadow components and target detection in shadow using polarization

Shadow is an inseparable aspect of all natural scenes. When there are multiple light sources or multiple reflections several different shadows may overlap at the same location and create complicated patterns. Shadows are a potentially good source of information about a scene if the shadow regions can be properly identified and segmented. However, shadow region identification and segmentation is a difficult task and improperly identified shadows often interfere with machine vision tasks like object recognition and tracking. A shadow separation and contrast enhancement method based on the polarization of light is provided. Polarization information of scenes is captured by a polarization-sensitive camera and the scenes are processed to effectively separate shadows from different light sources.