| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that, when an image is decided to be a character image, if the image is quantized by using a character image quantization step with a small quantization step size, a code quantity after encoding exceeds a maximum code quantity and a code cut-off process is necessary to ensure the maximum code quantity and, as a result, the quality of the image is deteriorated. SOLUTION: An orthogonal transformation is applied to an input image by an orthogonal transformation unit 11, and the input image is quantized by a quantization unit 12 by using a quantization step size in a quantization table. The quantization factors are rearranged into the single dimensional arrangement by a one-dimensional arrangement unit 14 and then coded into variable long codes. At that time, variable long code table 17 corresponding to respective symbols are selected by a Huffman table selection unit 16 and, by using the variable long code tables 17, the quantization factors arranged into the one-dimensional arrangement are coded into variable length codes according to the respective symbols.</p> |
