Image compression scheme for network transmission
Abstract
In this thesis a scheme is proposed for still image compression for realtime transmission over a packet switched network. A layered image compression scheme based on the quad tree decomposition technique (QTD) is developed. The image is decomposed into three layers, where layers are added to a base image to incrementally improve the quality of the reconstructed image. The performance of the QTD is enhanced by adding a DCT algorithm with adaptive bit allocation and a region of interest methodology. The quad tree is then extended to a nona tree whereby pixel blocks of size 3 x 3 are processed instead of 2 x 2. Results are presented to provide a visual subjective perception of the proposed scheme. Depending on the number of layers transmitted, the compression gains range from 60:1 to 16:1. It is shown that the proposed scheme exhibits graceful degradation of the reconstructed image and some error tolerant capabilities.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.Collections
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