1. A method for generating image correction factors, comprising: accessing a gain map image comprised of gain correction coefficients for one or more pixels of a detector array; applying a frequency-based transform to the gain map image to generate a high-frequency component of the gain map coefficients and a low-frequency component of the gain map coefficients for each pixel; determining the appropriate low-frequency components based on a source/detector geometry associated with an imaging system during the acquisition of an image; adjusting the low-frequency components based on the source-detector geometry; and correcting the image using the adjusted low-frequency components and the unadjusted high-frequency components.