| 摘要 |
PROBLEM TO BE SOLVED: To reproduce an image in which characters, line pictures, photographs and dots coexist with a high quality. SOLUTION: A filter processing part 110 smoothes the dot components of the 175 lines of image data. The edge level of the smoothed image data is detected by an edge detecting part 131, and the edge level is area-extended by an area extension processing part 132. A quantization threshold oscillating with oscillation width following the edge level after the area extension is generated by a quantization threshold generating part 140. The smoothed image data are quantized by a quantization processing part 120 by an error diffusing method by using the quantization threshold. |
