Subtraction method of x-ray image

PURPOSE: To conduct a mixing subtraction method in high speed by subtracting a double energy image on image from a double energy mask image before imaging to control or cancel a bone structure and separating only a blood vessel containing a contrast medium. CONSTITUTION: Two images in an approaching and successive pair are combined and subtracted, and the obtained difference image before imaging is memoried. Image data to make this picture element is multiplied by an amplification or a coefficient before its subtraction so as to cancel a soft texture to make the bone structure remain. Like T 10 , when a contrast medium reaches a bone, a series of exposure of approaching and successive low and high energy pairs are conducted and forms a difference image before imaging remaining blood vessel containing the bone structure and the contrast medium by multiplying the data to obtain these images using the same amplification, and by subtracting to cancel the soft texture using the same method. Then, by subtracting an optional difference image on imaging from an optional difference image before image to cancel all of common data in both, each image of the blood vessel filled with the contrast image is made to remain. COPYRIGHT: (C)1990,JPO