| 摘要 |
PROBLEM TO BE SOLVED: To improve the quality of a binary image such as a character image by reducing mosquito noise, that occurs when JPEG type coding and decoding are performed in communication equipment which handles color images. SOLUTION: This color image communication equipment decides the image area of a mixed image to a luminance signal in a color component signal in a decision circuit 1070, quantizes a halftone image by using a quantization reference value (a), quantizes binary image data by using a qunatization reference value (b) (a<b) and transmits them. A receiving side performs asymmetrical inverse quantization of the binary image data by using a reference value, whose value is the same as the value (a) and clamps a part which protrudes outside the dynamic range of luminance by a clamping circuit 1132.
|
