1. A camera system comprising: means for generating a corrected scene image signal comprising a series of signals corresponding with irradiance values at a plurality of locations of a scene image; means for refreshing the corrected scene image signal at a video frame refresh rate; a temporal filter memory for storing a temporally filtered scene image therein, said temporally filtered scene image comprising image signals corresponding with a temporal characteristic of irradiance values at each of the plurality of locations of the scene image over a selected time period; a temporal filter for receiving the corrected scene image and the temporally filtered scene image therein, for comparing the corrected scene image with the temporally filtered scene image, and for updating the temporally filtered scene image according to a temporal weighting factor based on a difference between corrected image signal values and temporally filtered image signal values and for storing an updated temporally filtered scene image in the temporal filter memory; and, an image difference calculator for receiving the corrected scene image signal and the updated temporally filtered scene image signal therein, for scaling the updated temporally filtered scene image signal by a scaling factor and for subtracting the scaled updated temporally filtered scene image from the corrected scene image to generate a difference scene image signal comprising a series of image signals corresponding with each of the plurality of locations of the scene image.