The larger memory and channel bandwidth requirements for digital video transmission and storage make it mandatory to use compression techniques. Representation of the video signal in a pyramid format not only compresses the signal but also makes it suitable for specific applications such as packet video based on asynchronous transmission mode (ATM) and compatible advanced television (ATV). In this thesis, we propose to employ a pyramid data structure for video compression. A review of video coding schemes is first presented, followed by a review of the various 2-dimensional (2D) and 3-dimensional (3D) pyramid data structures from the perspectives of data compression. The performance of different configurations of temporal/spatial pyramid data structures is then measured for video compression in terms of the first order entropy. Based on this study, we introduce an efficient 3D adaptive temporal/spatial pyramid which selects either the temporal or spatial contractions using the temporal and spatial prediction differences, respectively. We propose a video codec that combines the adaptive temporal/spatial pyramid and an intra-frame coding technique. Simulation results on CCITT standard video sequences indicate that the adaptive pyramid reduced the lossless bit rate by a factor of two. For video conferencing applications, excellent subjective quality as well as objective quality (PSNR value of 36.6 db) are obtained at a bit rate less than T1 rate (i.e. 1.544 Mbits/s). Promising results have been obtained for CCIR resolution (720 x 480), high detail sequences at a bit rate of 6 Mbits/s. Furthermore, smooth transition is achieved in the case of scene changes without sacrificing picture quality. Finally, the algorithm is well suited for constant bit rate and constant quality applications. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/6550 |
| Date | January 1993 |
| Creators | Gandhi, Rakeshkumar Hasmukhlal. |
| Contributors | Panchanathan, S., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 148 p. |
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