A motion-flow-based fast video retrieval system

In this paper, we propose the use of motion vectors embedded in MPEG bitstreams to generate so-called motion-flows, which are applied them to perform quick video retrieval. By using the motion vectors directly, we do not need to consider the shape of a moving object and its corresponding trajectory. Instead, we simply link the local motion vectors across consecutive video frames to form motion flows, which are then annotated and stored in a video database. In the video retrieval phase, we propose a coarse-to-fine strategy to execute the video retrieval task. Motions that do not belong to the main-stream motion flows are filtered out by our proposed algorithm. The retrieval process can be triggered by query-by-sketch (QBS) or query-by-example (QBE). The experiment results show that our method is indeed efficient and accurate in the video retrieval process.