| 摘要 |
<p>PURPOSE: To improve the efficiency of encoding in block units such as the reversible encoding of gradient image data, etc., by calculating a parameter to regulate a similar surface for the gradient of image data in a block and encoding the difference of the image data from the parameter and the similar surface. CONSTITUTION: Block data from a block generation circuit 102 is sent to a plane surface calculator 201 and a buffer 203. The calculator 201 calculates the parameter to define a plane surface by a prescribed method, and sends it to a plane surface generator 202 and a parameter encoder 205. The generator 202 generates plane surface data according to a received parameter, and outputs it to a subtracter 204. The subtracter 204 calculates the difference between input block image data from the buffer 203 and the plane surface data every picture element, and sends it to a Huffman encoder 206. The encoder 206 assigns a Huffman code to a built-in Huffman table, and outputs code data to a buffer 104 via a multiplexer 207.</p> |
