| 摘要 |
PROBLEM TO BE SOLVED: To enhance the image quality of a binary image such as a character image by reducing a mosquito noise produced in the case of coding/decoding with the JPEG system. SOLUTION: A discrimination circuit 1070 discriminates an image area of a mixed image, a quantization reference value aj is used to quantize a medium tone image and a quantization reference value bj (aj <bj ) is used to quantize binary image data and the result is transmitted. Asymmetrical inverse quantization is applied to the binary data at a receiver side by using a reference value the same as the quantization reference value aj and a clamp circuit 1132 clamps the luminance in excess of a dynamic range. |
