Image processing apparatus, X-ray image capturing apparatus and image processing method

Abstract

This invention provides an image processing apparatus capable of suppressing the variation in density and contrast of a long-length image that is a joint image obtained by joining a plurality of X-ray images. An image processing apparatus (6) comprises: an image memory (62) for storing the data of a plurality of X-ray images (20, 21, 22) partially overlapping with one another; a density / contrast correcting unit (64) for evening up the densities and contrasts of the plurality of X-ray images; and a long-length image obtaining unit (65) for joining all of the X-ray images (20, 21', 22") as evened up in density and contrast by the density / contrast correcting unit (64), thereby obtaining a long-length X-ray image corresponding to a long-length image-captured area of an examined body (M). The density / contrast correcting unit (64) comprises: a first table creating unit (642) for obtaining, based on image information of the overlapping portions (20a, 21a, 21b, 22a) of two adjacent ones (20, 21; or 21, 22) of the plurality of X-ray images, a gray scale conversion table (AB, BC) with which the densities and contrasts of the two X-ray images (20, 21; or 21, 22) can be evened up; a second table creating unit (643) for obtaining, based on the gray scale conversion table (AB, BC), a second gray scale conversion table (BA, CB) with which the densities and contrasts of a reference X-ray image (20) and other remaining X-ray images (21, 22) selected from the plurality of X-ray images (20-22) can be evened up; and an evening unit (644) for evening up the densities and contrasts of the remaining X-ray images (21, 22) on basis of the second gray scale conversion table (BA, CB).

Description

technical field [0001] The invention relates to an image processing device, an X-ray photographing device and an image processing method. Background technique [0002] When acquiring a long-span image as a stitched image using a plurality of partially overlapping X-ray images, it is known that the display densities of the images before stitching are matched and then combined to acquire the long-span image. For example, in the technique disclosed in Patent Document 1, first, each image before joining is subjected to logarithmic transformation. Next, a histogram of each image is obtained from each logarithmically transformed image. Next, a shift in the position of the center of gravity of each of the acquired histograms is detected, and the shift is corrected. In addition, the offset-corrected images are combined to obtain a long-span image as a joined image. [0003] Patent Document 1: JP-A-2007-275228 Contents of the invention [0004] However, the conventional method ...

AI Technical Summary

Problems solved by technology

When the contrast between images is different, a certain bone part may be clearly recognized in one image but not in other images.

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