| 摘要 |
<p>PROBLEM TO BE SOLVED: To attain image decoding without making image quality deterioration in a dot area conspicuous by converting a pattern corresponding to a pixel block in high-order bits of a quantization code into a pattern where adjacent pixel values are distributed while keeping number of 1s, 0s in existence in the pixel block in the case that a dot area discrimination signal is discriminated to be a dot area block. SOLUTION: A decoder has a dot area discrimination section 1208, and a primary code storage section 1205 conducts coding by using a dot area signal. The dot area discrimination section 1208 discriminates the dot area mainly by means of pattern matching or the like, and a pattern corresponding to a pixel block in high-order bits of a quantization code is converted into a pattern where adjacent pixel values are distributed while keeping number of 1s, 0s in existence in the pixel block in the case that the dot area discrimination signal is discriminated to be a dot area block. Thus, the dot image is reproduced from generated code data with better image quality than that decoded by a conventional block coding decoding method without any modification.</p> |
