New video object segmentation technique based on flow-thread features for MPEG-4 and multimedia systems

In this paper, we present a novel technique for video object (VO) segmentation. Compared to the existing VO segmentation methods, our method has the advantage that it does not decompose the VO segmentation problem into an initial image segmentation problem (segmenting a single image frame) followed by a temporal tracking problem. Instead, motion information contained in a finite duration of the image sequence is considered simultaneously. Given a video sequence, our method first estimates motion vectors between consecutive images, and then constructs the flow-thread for each pixel based on the estimated motion vectors. Here, a flow-thread is a series of pixels obtained by tracing the motion vectors along the image sequence. Next, we extract a set of flow-thread features (ft-features) from each flow-thread, which is then used to classify the associated pixel into the VO it belongs to. The segmentation results obtained by our unsupervised method look promising and the processing speed is fast enough for practical uses.