| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the influence of color shift due to chromatic aberration or the like by a scanner which reads an output sample in the correction of the registration error of an image forming apparatus. <P>SOLUTION: The color image forming apparatus 30 being an evaluation object outputs the evaluated image data 12 of each color material whose gradation is changed in a two-dimensional direction, and the output sample 40 is read by an image input device 13, thereby obtaining the read image of each color material. A registration error amount arithmetic part 14 develops the read image in frequency space, and calculates the two-dimensional registration error amount from the correlation of mutual phase spectrums (phase restricting correlation method). At such a time, the registration error amount arithmetic part 14 receives color shift amount between the respective color sensors of the image input device 13 registered in a storage part 15 for storing the color shift amount between the sensors, and corrects the registration error obtained by the phase restricting correlation method according to the color shift amount. <P>COPYRIGHT: (C)2007,JPO&INPIT |
