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.