| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image scanner and a correction method in which an MTF value can be obtained with less effect by noises and besides contrasts at edges of image data, thin lines and so forth are not lost. <P>SOLUTION: The image scanner is equipped with an image scanning section 11, a histogram making section 13 for making a histogram for pixel values of the number of pixels in the image data scanned from a manuscript for measurement, a peak calculator 14 for selecting the highest two peaks in the histogram to define the pixel value of the peak at a near side to a predetermined black reference value and that at a near side to a predetermined white reference value as a black peak value and a white peak value, respectively, an MTF value calculator 15 for determining a value according to a modulation transfer function by using a given expression on the basis of the black reference value and the white reference value, the black value of the peak and the white value of the peak, and a corrector 17 for correcting the image data on the basis of the modulation transfer function. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
