| 摘要 |
<p>PURPOSE:To prevent deterioration in picture quality in a picture in which a natural picture and a color character picture are in mixture in an ADCT multi- value color picture compression. CONSTITUTION:An image area is separated based on a DCT coefficient after a DCT section 3 in the ADCT method, a natural picture use quantization factor 8 and a quantization table 12 are used for a natural picture and proper quantization factors 9, 10, 11 are selected among plural kinds depending on the size of the absolute value of the DCT coefficient for a color character and it is quantized by using a character use quantization table 13. Thus, a difference from the deterioration in the color character picture, especially from the deterioration in a character due to its color is avoided.</p> |
