An image processing apparatus acquires a radiation image obtained by irradiating an object with a radiation from a radiation generating apparatus. The image processing apparatus estimates a scattered radiation component and a primary radiation component included in the acquired radiation image, wherein the image processing means is arranged to approximate an intensity of a scattered radiation which is a radiation scattered on a path from the radiation generating apparatus to a radiation detecting element for providing a pixel value of the acquired radiation image, for a path by using a plurality of scattered radiation models having different attenuation distances on the path, and further perform the approximation on the pixel value corresponding to an output from the radiation detecting elements to estimate the scattered radiation component and the primary radiation component. The image processing apparatus outputs a corrected image based on the primary radiation component.
