Seonghoon Kang
Center for Artificial Vision Research, Department of Computer Science and Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul 136-701, Korea
Bon-Woo Hwang
Center for Artificial Vision Research, Department of Computer Science and Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul 136-701, Korea
Seong-Whan Lee
Author for correspondence.
Center for Artificial Vision Research, Department of Computer Science and Engineering, Korea University, Anam-dong, Seongbuk-ku, Seoul 136-701, Korea

We present a method for detecting and tracking multiple people totally occluded or out of sight in a scene for some period of time in image sequences. Our approach is to use time weighted color information (i.e. the temporal color) for robust medium-term people tracking. The temporal color is the set of pairs of a color value and its associated weights. The weight is related to the size, duration and frequency of appearance of the color region, as well as the number of people adjacent to the target person. It assures our system to continuously track people moving in a group with occlusion. Most systems have built an appearance model for each person to solve occlusion problems. The appearance model contains certain information on the target person — color, shape, texture, position, velocity and face pattern. We use temporal color in the appearance model for the identification of the people occluded or out of sight in the scene upon their reappearance. Experimental results show that the temporal color is more stable than shape or intensity in various cases.

Multiple object tracking; visual surveillance; multiple people detection; appearance model; temporal color; human activity recognition