| 摘要 |
An apparatus for compressing and coding the image data for each block wherein the image data is first divided into a plurality of image data of the blocks and then the image data of the block is subjected to orthogonal transformation, quantization, and variable length coding. Before the actual coding process, a statistical process is performed to obtain the amount of code data for the respective blocks, an optimum quantization step coefficient for the orthogonal transformation coefficients of the AC components based on the amount of code data for the block and the reference amount of code data, and the amount of code data of the orthogonal transformation coefficients of the AC components for the block. In the actual coding process, the provisional quantization step is used for quantizing the orthogonal transformation coefficients of the DC component and the optimum quantization step is used for quantizing the orthogonal transformation coefficients of the AC component. The coding of the orthogonal transformation coefficients of the AC components is stopped when the amount of code data of the block exceeds the assigned amount of code data.
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