| 摘要 |
PROBLEM TO BE SOLVED: To prevent the contrast loss of a pixel of low using frequency by dividing an image screen into the windows which are superimposing on each other and equalizing a histogram. SOLUTION: This device consists of an image data storage part 80, a comparator 84 and a counter 86 constituting a histogram calculation part 82, an accumulator 90 and a conversion function execution part 92 constituting an equalization value generation part 88, an LUT(look-up table) 94, an LPF(low pass filter) 96, a switch 98, an equalization value storage part 100 and a control part 102. Then a window is put over the device after the equalization of a histogram is ready, and the histogram, a conversion function and then the equalization value of a prescribed number of pixels are calculated. The histogram equalization value is decided or the window is moved according to the presence or absence of the final window. Under such conditions, the window put over an equalized image screen is superimposed on a prescribed part of the moved window with each other. It is also desirable to include a prescribed number of pixels in a superimposing part. Then the image screen is divided into the windows superimposing on each other, and the histogram is equalized. |
