Method and apparatus for sensing an image

摘要

An image sensing apparatus using a solid state image sensor has the capability of correcting an image signal including an intensity variation due to the variation in the intensity of a radiation from a radiation source and also including an intensity variation due to the variation in conversion efficiency of photoelectric conversion elements in such a manner that only the variation in conversion efficiency is corrected thereby suppressing an artifact which would occur in conventional apparatus. A shading distribution (distribution data) is measured by sensing an X-ray through no object to be examined or through an object whose transmittance to the X-ray is well known. The component of the X-ray intensity distribution is separated from the obtained shading distribution data thereby obtaining a pixel-to-pixel variation in conversion efficiency of the solid state image sensor. The image signal is corrected based on the pixel-to-pixel variation in conversion efficiency obtained.