| 摘要 |
<p>PURPOSE: To obtain highly compressed data by encoding only the effective coefficient in an image block data after a zigzag scan by using a DC coefficient code table, omitting a process for run-length counting, and encoding all only with the DC coefficient code table. CONSTITUTION: An encoding device 40 consists of a DCT converter 42, a quantizer 44, an effective coefficient position information generation part 46, and an effective coefficient encoder 48. An image to be processed is inputted to the DCT transforming unit 42 first by blocks of 8×8 pixels and transformed into DCT coefficients, which are quantized by the following quantizer 44 by using a quantization table 52. Consequently, quantized data are obtained and encoded by using only the DC coefficient code table 50. Consequently, the need for an AC coefficient code table is eliminated and when the effective coefficients are put together at left upper parts of the blocks of 8×8 pixels, the effect that there is no decrease in compressibility is obtained.</p> |
