Patent ID: 6563942
Filing Date: 2003-05-13
Classification: G06T

Abstract:
A method for adjusting positions of radiation images, wherein the positions of a plurality of radiation images are matched to one another such that the radiation images may be subjected to superposition processing or subtraction processing, the method comprising the steps of:i) setting template regions on a single radiation image, which is among the plurality of the radiation images, ii) carrying out template matching, with which said template regions are matched with the radiation images other than said single radiation image, iii) thereby obtaining at least three corresponding points in each of the plurality of the radiation images, iv) taking the corresponding points in a single radiation image, which is among the plurality of the radiation images, as reference corresponding points, v) calculating factors of affine transformation with the method of least squares, said affine transformation being represented by the formula: (uv)=(abcd)&it;(xy)+(ef)wherein u and v represent the coordinates of the reference corresponding point, x and y represent the coordinates of the corresponding point to be transformed, a, b, c, and d are the factors representing correction with a rotating operation and correction with an enlargement or reduction factor, and e and fare the factors representing correction with parallel translation, and vi) carrying out affine transformation, in which the calculated factors of affine transformation are used, and with which the values of coordinates of the corresponding points in the radiation images other than said single radiation image having the reference corresponding points are transformed into values of coordinates of the reference corresponding points such that the reference corresponding points and the transformed corresponding points in the radiation images other than said single radiation image having the reference corresponding points may coincide with one another; wherein said affine transformation step is performed so that each of enlargement or reduction, rotation, and parallel translation of the radiation images, other than said single radiation image, occur simultaneously; and wherein the plurality of the radiation images are recorded with a radiation source and a one-shot image recording operation, and the reference corresponding points are set in the radiation image which has been obtained at the position closest to the radiation source.