| 摘要 |
PROBLEM TO BE SOLVED: To remove the influence of scattered rays by finding the mean luminance values of a small circumference of a noticed pixel and its peripheral part, and adjusting a low-frequency component according to the relation between the mean luminance of the small circumference and the mean luminance of the peripheral part and then subtracting it from a digitized image signal. SOLUTION: X Rays having been transmitted through a subject 10 are converted by an image intensifier 12 into an optical image, whose image signal is converted into digital image data by an A/D converter 15 and then sent to a digital image processor 16. Then a low-frequency component extracting circuit 21 extracts the low-frequency component of the image, a small- circumference mean luminance calculating circuit 22 finds the mean luminance of the small area at the periphery of the noticed pixel, and a circumferential part mean luminance calculating circuit 23 finds the mean luminance of the relatively wide area at its periphery. Further, a scattered-ray influence degree calculating circuit 24 calculates the degrees of scattered ray influence by pixels from the mean luminance values, and a multiplier 25 multiplies the low-frequency component by the degrees of influence and sends the results to a subtracter 26, which subtracts them from the original digital image data. |
