ENCODER AND ENCODING METHOD, DECODER AND DECODING METHOD, IMAGE PROCESSING SYSTEM AND IMAGE PROCESSING METHOD, RECORDING MEDIUM, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To more easily make it impossible by using Laplacian information to copy image data while maintaining image quality without deteriorating the quality of an image displayed on the basis of the image data before copying.

SOLUTION: In this encoding method, a block dividing section 101 divides supplied frame data into blocks, and supplies the pixel value of each pixel of the digital image data per block to a Laplacian information determining section 102. The section 102 obtains Laplacian information (information about whether a locus depicted by pixel values of a target pixel and adjacent pixels is "convex" or "concave" in the target pixel) of each pixel, and supplies the Laplacian information of each pixel and the pixel value per block to a quantization section 103. The quantization section 103 executes quantization on the basis of the Laplacian information of each supplied pixel and the pixel values per block so that the Laplacian information may be maintained after quantization, and outputs the minimum value of each block, a dynamic range of each block and a quantization code of each pixel as the quantization data. This method is applicable to an image display system, an encoder and a decoder.

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