| 摘要 |
A histogram is prepared by calculating the pixel number ratio corresponding to each gradation in relation to the total number of pixels in image data obtained from the outside. A threshold value for the pixel number ratio corresponding to a given gradation that is determined through user specification is compared against the pixel number ratio corresponding to each gradation in the histogram. Based upon the results of the comparison, the histogram gradation width is corrected. For instance, the width representing the range of gradations with pixel number ratios smaller than the threshold value in the histogram is compressed. Then, the gradation width in the histogram is expanded to achieve the number of pre-compression gradations.
|
