Segmentation of a 3D scene into free areas and object surfaces by using occluded edges of trinocular stereo

Proposes a new approach in which a 3D scene is segmented into free areas and object surfaces using: (1) sparse data which are obtained from trinocular stereo; and (2) occluded edges which can not be seen from at least one of the three cameras. Trinocular stereo is employed not only because it is more reliable for finding correspondences than binocular stereo, but also because it clearly classifies edge segments into 3D edge segments which can be seen from all three cameras and ones which can not be seen from at least one of the three cameras. The approach proposed consists of three steps: (1) to obtain free areas by using 3D edge segments which can be seen from all three cameras; (2) the free areas can be expanded by using edges occluded from at least one of the three cameras; and (3) to determine object surfaces. It is necessary to determine whether the 3D edge segments are occluding boundaries by using occluded edges which can not be seen from one of the cameras. One side of an occluding boundary can be taken to be an object surface. Therefore, object surfaces can be inferred using the occluded edges in trinocular stereo