Digital imaging sensor identification (further study)

Abstract

In this paper, we revisit the problem of digital camera sensor identification using photo-response non-uniformity noise (PRNU). Considering the identification task as a joint estimation and detection problem, we use a simplified model for the sensor output and then derive a Maximum Likelihood estimator of the PRNU. The model is also used to design optimal test statistics for detection of PRNU in a specific image. To estimate unknown shaping factors and determine the distribution of the test statistics for the image-camera match, we construct a predictor of the test statistics on small image blocks. This enables us to obtain conservative estimates of false rejection rates for each image under Neyman- Pearson testing. We also point out a few pitfalls in camera identification using PRNU and ways to overcome them by preprocessing the estimated PRNU before identification.