Reconstruction of curved surface using isodensity maps based on stereo vision system

The passive stereo vision systems is one of the most general techniques of obtaining 3D information from objects. A common problem in stereo systems is finding the corresponding points in the two images of a scene. To cope with this problem, edge-based stereo methods have been considered useful. For curved surfaces, however, edge-based stereo cannot be applied because of the difficulty of extracting edges from curved surfaces. In this paper, we propose a new stereo algorithm based on isodensity lines extracted from a curved surface. Isodensity lines are extracted by tracing pixels having the same density. The proposed algorithm consists of two processes. The first is the process of finding corresponding isodensity lines between two images. The second process is finding one-to-one pixel correspondence along corresponding isodensity lines, for fine matching. With this algorithm, objects with curved surfaces can be reconstructed--even objects having no edges--and poorly corresponding points can be corrected easily. Though some problems are still to be investigated thoroughly, computer simulation results show good accuracy. From the experimental results, the use of this method for the 3D reconstruction of objects with curved surfaces can be considered a serious possibility.