A method of reducing an amount of fixed pattern noise from an image signal generated by an image sensor. The method includes, for each operational pixel in the image signal, applying a recursively updated offset term to generate a corrected image signal. The offset correction terms are recursively updated by spatially filtering the corrected image signal for a current frame of the image signal; comparing the filtered corrected image signal of the current frame with a spatially filtered corrected image signal of a preceding frame of the image signal; and updating the offset correction terms with terms generated as a function of the comparison.