| 摘要 |
PROBLEM TO BE SOLVED: To relax a specific step difference in the output signal of a scanner. SOLUTION: A scanner unit 26 is configured by coupling pluralities of line sensor chips. Thus, a step difference corresponding to a chip coupling section appears a specific period in output data. Then a density difference arithmetic section 54 that calculates a density difference between adjacent pixels, a comparison section 55 that compares the density difference with a reference value, and a period discrimination section 56 that collates the comparison result by the comparison section with a specific period are used to discriminate whether or not each pixel is a pixel corresponding to the step difference. A flag corresponding to the discrimination result is written in a flag line memory 53. Based on the written flag, a filter control section 52 changes a filter coefficient of a differentiation filter 51. That is, filter processing to relax a density difference between pixels is applied to density data corresponding to the pixels of the step difference part. |
