METHOD FOR JUDGING IMAGE SHARPNESS, RECORDING MEDIUM HAVING PROGRAM FOR PERFORMING PROCESSING DECIDING IMAGE SHARPNESS RECORDED THEREON, IMAGE PROCESSOR AND PHOTOGRAPHIC PRINTER

摘要

PROBLEM TO BE SOLVED: To appropriately, easily and also stably perform the sharpness judgement of an original image by using the original image and its blurred image. SOLUTION: When a BGR/luminance converting part converts the BGR image data of the original image into luminance image data (pixel values) (S1), a smoothed image preparing part prepares the smoothed image of the original image on the basis of the pixel values (S2). A 1st edge intensity calculating part calculates the edge intensity of the original image (S3). Meanwhile, a 2nd edge intensity calculating part calculates the edge intensity of the smoothed image (S4). A sharpness deciding part calculates the relative frequency distribution of an edge intensity ratio (S5). The sharpness judgement part calculates the ratio of a relative frequency corresponding to mutually different edge intensity ratios (S6) and judges the sharpness of the original image by judging whether or not the ratio is equal to or greater than a threshold (e.g. 1) (S7).