Occlusion handling for a target-tracking robot with a stereo camera

Abstract

This paper presents an occlusion-handling method for a target-tracking robot with a stereo camera. One of the main challenges with the robot is to continue tracking when the illumination changes and occlusion occurs. In order to cope with the challenge, we use both color and disparity images acquired from a stereo camera. The tracking system is composed of three phases: candidate extraction, target identification, and occlusion handling. First, by using only three-dimensional (3D) information, target candidates are extracted. Second, the target is identified from the candidates based on a combination of both color and location features of the target and candidates. The combination depends on illumination changes that are supposed by changes in the white balance. Finally, the state of occlusion is estimated by results of both the analysis of the positional relationship between the candidates and the identification of a target. The proper procedure for the state is implemented. In the off-line experiments, the proposed method is compared with previous methods. Then, the proposed method is applied to a mobile robot, and an on-line experiment is carried out. Through the experiments, the effectiveness of the proposed method is verified.