An imaging system comprises: a plurality of pixels each for converting light, converted from radiation by a conversion unit, into an electrical signal an extracting unit that extracts, based on an image formed based on output signals from the pixels, a pixel with noise generated by the radiation that has transmitted through the conversion unit to arrive at the pixels and a correcting unit that performs correction to remove the noise with respect to an output signal from the extracted pixel, wherein the extracting unit extracts the pixel with the noise by performing division between first and second images, the first image being formed based on the output signals from the pixels in accordance with the radiation to the conversion unit during a first period, the second image being formed based on these output signals in accordance with that radiation during a second period after the first period.
