| 摘要 |
PURPOSE:To achieve a highly accurate correction of an image distortion, by a method wherein a member low in the radiation absorption coefficient is combined flat with a member high in the coefficient so as to arrange numerous imaging points of a member intended to measure distortion in scattered dots and a distortion measuring phantom thus formed is processed through photography. CONSTITUTION:A member low in the radiation absorption coefficient is combined flat with a member high in the coefficient so as to arrange numerous imaging points of a member intended to measure distortion in scattered dots, a phantom intended to measure distortion is photographed as the object and an image signal thus obtained undergoes a filter processing 2. An imaging portion of the number intended to measured distortion extracted is processed 3 on a threshold basis to define parts above a certain level as imaging point areas, the gravity center in which is determined to detect 4 distortion imaging points of the member intended to measure distortion. Then, true imaging points for image formation are set 5 for the member intended to measure distortion and then, distortion coordinates of a desired pixel except for points of the member intended to measure distortion are determined from the true image points and the distortion imaging points by interpolation processing. Then, a distortion correction table is prepared and recorded 7 from the results of computation and is used to correct an image distortion.
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