Real-time Shadow Removal using a Volumetric Skeleton Model in a Front Projection System

When a person is located between a display and a projector in operation, a shadow is cast on the display. The shadow on a display may eliminate important visual information and therefore adversely affects the viewing experiences. There have been various attempts to remove shadows cast on a projection display by using multiple projectors. We propose a real time novel approach to removing shadow cast by the person who dynamically interacts with the display making limb motions in a front projection system. The proposed method utilizes a human skeleton obtained from a depth camera to track the posture of the person which changes over time. A model that consists of spheres and conical frustums is constructed based on the skeleton information in order to represent volumetric information of the person being tracked. Our method precisely estimates the shadow region by projecting the volumetric model onto the display. In addition, employment of intensity masks that is based on a distance field helps suppress the afterimage of shadow that appears when the person moves abrubtly and smooth the difference of the brightness caused by different projectors at the boundary of the shadow region.