Semiautomatic Segmentation Using Spatio-Temporal Gradual Region Merging for MPEG-4

The video coding standard MPEG-4 is enabling content-based functionalities. It takes advantage of a prior decomposition of sequences into video object planes (VOP's) so that each VOP represents a semantic object. Therefore, the extraction of semantic video objects is crucial initial part. In this paper, we present an efficient region based semi-automatic segmentation system, which combines low level automatic region segmentation with interactive method for defining and tracking high level semantic video objects. The proposed segmentation system extracts accurate object boundaries using gradual region merging and bi-directional temporal boundary refinement. The system comprises of two steps: an initial object extraction step where user input in the starting frame is used to extract a semantic object; and an object tracking step where underlying regions of the semantic object are tracked and grouped through successive frames. Experiments with different types of videos show the efficiency of the proposed system in semantic object extraction.