Video object segmentation is an important task in object-based video coding.In this paper

an automatic video segmentation scheme based on higher-order statistics (HOS) of displaced frame differences (DFD) and mathematical morphological operators is studied.In this approach

a map (mark) overlapping object is first gotten by thresholding a group of higher-order moment maps of DFD

and then a morphological erosion from the boundary of the mark up to the boundary of the object is performed to get the final segmentation map.A simple but efficient algorithm for separating head and shoulder is proposed based on searching for the greatest degree turning-point in head-shoulder contour curve.Based on segmentation

the MPEG-4 based video coding system we implemented with software is described.Then

a very low bit-rate video coder with object-oriented bandwidth allocation (OOBA) technology is proposed.Compared with conventional frame-based video coder

the OOBA-coder can improve subjective quality of images at low bit-rate

while decrease PSNR just a little.