| 摘要 |
PURPOSE:To detect abnormality at high speed by storing plural sheets of an object image, calculating the hysteresis data, calculating an offset value obtained by subtracting a difference in brightness between a detected object and the background from the brightness of the background, and adding an image, the background brightness of which is lowered. CONSTITUTION:A central processing portion 15 selects a gradation with a large distribution from the hysteresis data calculated by a hysteresis calculating portion 14 to be taken as a background density. The processing portion 15 sets a value obtained by subtracting the minimum density difference of an abnormal portion to be detected from the background density as an offset value in an offset storage register 16. The digital image data output from an A/D converter 13 is input to an arithmetic unit ALU1, and a storage value of the register 16 is subtracted therein. Thus, the information on an object to be detected is left undone, but the brightness level of the background can be lowered. Plural sheets of images, the background brightness of which are lowered, are added to increase the contrast of an object to be checked, and noise generated at random can be made average and reduced by the storage effect. |
