| 摘要 |
PROBLEM TO BE SOLVED: To perform threshold processing on gray-scale input pictures in such a state that the resistance to noise can be improved and pseudo contours near a boundary section can be reduced, and then, low-contrast objective pictures can be detected accurately. SOLUTION: A device for performing threshold processing on gray-scale input picture is constituted of means 610, 615, 617, and 620 which decide the intensity gradient value of an area by using a first matrix having a prescribed size, a means 635 which decides the maximum and minimum values out of the intensity values of the picture elements contained in a second matrix, and means 625, 640, 650, 655, 660, 680, and 690 which perform threshold processing so as to change the intensity values of the picture elements at the positions (i, j) of objective picture elements in the picture to the intensity values of output picture elements based on the intensity gradient value of the area and the maximum and minimum values of the intensity values of the picture elements. |
