Displacement information is important in dynamic image analysis. The method of optical flow has been well applied to compute the displacement in the field of computer vision. We apply the method of optical flow to compute the displacement information for video compression. We can predict the optical flow between picture 2 and picture 3 by the optical flow between picture 1 and picture 2 by using the principle of inertia. Using the predicted optical flow between picture 2 and picture 3, we can recover a rough version of picture 3. This version can be taken as a reference picture for encoding picture 3. This reference will decrease the compensation information in the following stage, and then improve the compression ratio of MPEG .
We modified the traditional optical flow of Horn & Schunck to a regional optical
flow by segmentation. Then, the displacement information could be reduced. The
picture is recovered by the optical flow in a modified way because some objects
couldn¡¦t move in the same direction and velocity. We propose two methods in
optical flow prediction. One is the complete information: shape and value. The
other is shape only with value recomputed and extra encoded. Experiments
demonstrate a better compression ratio of 1% for our motion compensation than
the regular motion compensation.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0805102-174542 |
| Date | 05 August 2002 |
| Creators | Young, Ga-U |
| Contributors | Tsung Lee, Ben-Shung Chow, Chin-Hsing Chen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0805102-174542 |
| Rights | not_available, Copyright information available at source archive |
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