The correction amount of an aberration caused in each pixel of the region by the optical system is calculated. A predetermined number of peripheral pixels center on a position apart from the pixel by the distance corresponding to the calculated aberration correction amount are multiplied by interpolation coefficients obtained from an interpolation function and added, thereby deriving the pixel value at the pixel position after correction. If the predetermined number of peripheral pixels around the position apart by the distance corresponding to the calculated aberration correction amount are not present in the readout region, aberration correction is implemented by changing the interpolation function. More specifically, the interpolation function is changed so as to make the frequency response behavior of the interpolation function more moderate than that of the interpolation function that gives the interpolation coefficients to multiply the predetermined number of peripheral pixels and used in the correction processing.