| 摘要 |
PURPOSE: To prevent the emphasis of a noise in a picture by adjusting the luminance value of each selected picture according to a mapping function for conversion from a screen element luminance value to an adjusted picture element luminance value, and replacing the luminance value level of the selected picture element with the corresponding adjusted picture element luminance value. CONSTITUTION: A processor 34 calculates the histogram of a occurrence frequency versus picture element luminance value in a principal area, a low pass filter 36 is operated to those histograms, and plural filtering-operated histograms are generated. A mapping function being a function for adjusting the original luminance value of a picture element to each filtering-operated histogram is calculated. Each selected picture element is adjusted according to the mapping function corresponding to the picture element, and the plural adjusted picture element luminance values are calculated. The luminance values of the original picture are converted into the corresponding adjusted luminance values, and contrast at the time of display is emphasized. Thus, the emphasis of the noise in the picture can be prevented. |
