A method and system are provided for generating high and low-frequency components for the pixels of a detector array. The method includes the act of generating a gain map image comprised of gain coefficients for one or more pixels of a detector array. A frequency-based transform is applied to the gain map image to generate a high-frequency component and a low-frequency component of the gain map coefficients for each pixel. The high and low-frequency components may be differentially applied in the processing of images.