Interestingly, reading the fourth chapter, the first time this technique of identifying the sensor based on the specific noise characteristics was 2005. I bet this was tacitly well known far before 2005.<p>There are many camera from pre - 2005 that did dark frames and flat frames, for example Sinar digital backs. They all came with a CD with the unique calibration file for the back to tune out these characteristics to a large degree. Without them, you can see literally see the difference in exposure down the center of the image from the two stitched lithography mask shots required to make large CCDs at the time.