Adaptive skin segmentation for head and shoulder video sequences

In recent years, there has been much interest in object- oriented video coding schemes as an alternative to conventional video coding schemes, particularly for very low bit rate applications such as the coding of head and shoulder sequences for video conferencing. Automatic face detection is desirable in object-oriented video coding schemes that seek to code head and shoulder video sequences. However automatic face detection is not a trivial problem when complex backgrounds are present. We propose a novel method of adequately characterizing skin color by exploiting the luminance and chrominance information found in the first frame of a sequence. The skin color characterization is then used to facilitate skin segmentation in subsequent frames, and thereby automatic face detection. To aid the adaptive skin characterization process, the head is constrained to a frontal, upright position in the first frame of the sequence. However no constraints are placed on the position of the head in the subsequent frames. The proposed scheme was tested on a number of common H.263 and MPEG-4 head and shoulder video sequences. Some experimental results are presented.