Removing camera fingerprint to disguise photograph source

Sensor-based camera source identification (CSI) is believed to be an effective tool for linking a photograph to its source camera. In this paper, we propose a photo response non-uniformity (PRNU) removing attack on CSI. The PRNU fingerprint is a kind of multiplicative noise, and is believed to be difficult to be removed from an image. In this work, both the pattern and magnitude of the PRNU fingerprint of an unaltered image are estimated first, then it is subtracted from the target image. Theoretical analysis and experimental results show that the PRNU fingerprint can be removed using only common processing techniques without introducing visual artefact, therefore CSI can be easily defeated.