Television – Bandwidth reduction system – Data rate reduction
Patent
1993-02-25
1995-04-25
Britton, Howard W.
Television
Bandwidth reduction system
Data rate reduction
348423, 348395, 348396, H04N 7133
Patent
active
054103525
ABSTRACT:
An image data compressing apparatus comprises a transform unit, such as a DCT computation unit, a quantization table memory for plural types of quantization tables, a quantizer which selectively uses the quantization tables, a coder for performing coding in accordance with a pre-given predicted value for the amount of generated codes of each block, memories for storing the amounts of codes for DC components and AC components generated for the individual blocks, a computation unit for computing the sum of the amounts of generated codes for DC components and the sum of the amounts of generated codes for AC components for each properly selected quantization table, and memories for storing the computed sums of the amounts of generated codes, wherein the apparatus uses a plurality of quantization tables to predict a change in the amount of generated codes caused by the alteration of the quantization table in the first compression, and compresses image data to the target amount of generated codes in the second compression.
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IEEE 1988 Custom Integrated Circuits Conference, A Video Rate 16.times.16 Discrete Cosine Transform 1C, A. M. Gottlieb, et al, pp. 8.2.1-8.2.4.
IEEE Transactons on Communications, vol. Com. 25, No. 11, Nov. 1977, Adaptive Coding of Monochrome and Color Images, Wen-Hsiung Chen, et al, pp. 1285-1292.
Britton Howard W.
Casio Computer Co. Ltd.
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