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An adaptive orthogonal transform coding algorithm utilizing the classification technique is presented. Coding efficiency for natural images can be improved by adjusting coding parameters in accordance with the local property of images. ‘Classification’ is used to categorize small areas of an image into classes based on their characteristics. High coding efficiency results from changing coding parameters adaptively according to the classification index. Classification methods using ac energy, binary pattern and vector quantization index ere compared, and the advantage of the classification method with the vector quantization technique is shown. Also, an orthogonal transform coding algorithm with an adaptive variable length ceding method is proposed, and its structure and characteristics are described. A coding parameter normalization method to avoid mismatches between input images and coding parameters is also described. Coding experiments show excellent performance of this algorithm, for example, the number of hits for obtaining 40-dB SNR of monochrome ‘GIRL’ is 0.65 bits/pel, which is 20 percent smaller than conventional methods. [ABSTRACT FROM AUTHOR]

Compact and low-cost video coding equipment is indispensable for the economical realization of visual communication services such as traffic monitoring entertainment relay, etc. This paper describes an LSI oriented coding algorithm which is effective for the compact and economical realization of intra-frame coding equipment. First, an intra-frame combinational difference coding algorithm is proposed. The encoded picture quality obtained using this coding algorithm is sufficient even for complicated scenes of TV signals. The predictive coding circuit LSIs for realizing this coding algorithm are also developed. Moreover, the variable-length word multiplexing circuit is shown to be suitable for LSI, and LSIs for this are also developed, and its compactness is confirmed. A coding experiment was performed by using the developed equipment and it is shown that the equipment is capable of transmitting good quality ITV signals at a 32-Mb/s rate. [ABSTRACT FROM AUTHOR]