| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of forming an image having no jaggy at an edge portion even if binary image data already subjected to screen processing are inputted. SOLUTION: When binary data already subjected to screen processing are inputted, a multi-value section 41 makes the data multi-valued by a low-pass filter, and converts the data into multi-value image data. Further, ranking is performed based on values of the multi-value image data to normalize the data. An edge extracting section 42 extracts an edge portion by an edge filtering section on the basis of the normalized multi-value image data. For pixels extracted as the edge portion, a gradation correcting section 43 executes gradation correction processing, and then, a re-binarizing section 44 generates binary image data by dot screen processing with a high-line number of 0 or 90 degrees. A selecting section 45 selects the binary image data generated in the re-binarizing section 44 for the edge portion and selects the input binary image data for a non-edge portion to acquire the binary image in which the processing is applied to only the edge portion. COPYRIGHT: (C)2006,JPO&NCIPI
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