A new algorithm for resolving position reversal problems in stereo matching using dynamic programming

In binocular stereo vision, since color and distance information can be obtained simultaneously by a passive method which will not affect the environment, it is expected to be commonly used in the vision of future mobile robots. However, it is necessary to solve difficult problems such as finding corresponding points in the right and left images. Many stereo algorithms dealing with this problem have been proposed so far, all with their own weaknesses. This paper considers the position reversal problem, in which the positions of the corresponding points change places on the right and left scan lines. This is a subject in which there has been little progress despite its importance in obstacle detection by mobile robots. It has been considered that the position reversal problem cannot be processed correctly in plain dynamic programming for global matching unless the assumption that the positions of the corresponding points do not change places is forced. In the method proposed in this paper, four states are set in the search for the corresponding points. The search using dynamic programming is performed in two stages so that the position reversal problem can be solved while the above assumption is maintained. Then, matching also becomes possible in the case of objects for which the positions of the corresponding points change places. The proposed method is experimentally applied to the search problem in which the positions of the corresponding points change places inside scan lines, and its effectiveness is verified.