| 摘要 |
PROBLEM TO BE SOLVED: To provide an image processing method for precisely detecting a shading part, and to provide an image processor, an image forming device and an image processing system. SOLUTION: In image data D1 (refer to diagram (a)) obtained by reading a double spread original, a histogram H1 (refer to diagram (b)) is obtained when concentration integrated values obtained by integrating a concentration value on a pixel data string for one line along a Y-axis direction are obtained for all X-coordinate values. Peaks H1a, H1b and H1c in the histogram H1 respectively correspond to a saddle stitch shading part D1a, a right end shading part D1b and a left end shading part D1c. When Fourier transformation is performed on the histogram H1, a spatial frequency distribution F1 (refer to diagram (c)) is obtained. Peaks F1a and F1b are extracted as strong peaks at a low spatial frequency. When inverse Fourier transformation is performed on the peaks, a histogram H2 (refer to diagram (d)) showing only a saddle stitch shading part, a right end shading part and a left end shading part is obtained. COPYRIGHT: (C)2005,JPO&NCIPI
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