<title>Knowledge-based videotelephone sequence segmentation</title>

Abstract

This paper presents a robust knowledge-based segmentation algorithm for videotelephony sequences ranging from studio based to mobile. It is able to divide each image in a sequence in non-overlapping head, body, and background areas. Its robustness stems from its ability to cope with the peculiarities of mobile sequences, having very detailed, moving backgrounds as well as strong camera movements (originating from vibration in car videotelephones or from small hand movements in hand-held videotelephones). The proposed algorithm uses edge and changed areas (due to speaker's motion) detection, as well as the redundancy associated to the speaker's position, as the basis for the segmentation. Geometrical knowledge-based techniques are then used to define the complete regions. The algorithm includes a quality estimation and control procedure, which enables it to decide whether to accept or reject the current segmentation, and which can be input to the videotelephone coder.