| 摘要 |
<p>PURPOSE:To perform quantization by adaptively switching plural quantization tables through simple constitution without adding information for selection. CONSTITUTION:This image encoding device is provided with a block division part 11 which divides an image signal into blocks 8X8 pixels, a discrete cosine conversion part 12 which performs discrete cosine conversion, block by block, the quantization tables 15 and 16 which are equal in the quantization step size of DC components and different in the quantization step size of AC components, a DC component quantization part 13 which quantizes the DC component of the discrete cosine conversion output and compares the quantization output value with a threshold value, and makes a selecting means 17 select the quantization table 15 when the output value is less than the threshold value or the quantization table 16 when not, an AC component quantization part 14 which quantizes the conversion output of the AC component using the selected quantization table, and a Huffman encoding part 18 which encodes the quantization outputs from the respective quantization parts.</p> |
