Video segmentation is an important step in image recognition and in video coding based on MPEG 4 standard. This paper proposes a robust video segmentation algorithm which can greatly segment not only multiple VOs but also single VO from the static background. From the research

it is found that the raw contours of the active objects in the sequential video frames can be gained fast and exactly by using symmetrical DFD. So first use every three continuous video frames to get symmetrical DFD

then acquire the motion area of the moving object. Second analyze the result of the symmetrical DFD by clustering to inspect the number of VOs in the video frame. During clustering analyzing

not employing the traditional fuzzy C clustering mode

but employing a new clustering mode with using the body's characteristic which is proposed firstly in this paper. Third use the active contour algorithm in the binary image to get the contours that enclose the VOs accurately. By this step acquire the result of segmentation. Last

track the VOs in the video frames by the vectors of optical flow and also modify the result in some special conditions. All tests receive the ideal segmentation effects by using this algorithm with several image sequences. The experimental results show that this algorithm can complete video segmentation both for multiple VOs and for single VO in the static background correctly

so this algorithm has some robusticity and practicality.