One-time Camera Fingerprint: Unauthorized Photography Detection under Modulated Illumination

In this paper, we propose an unauthorized photography detection technique by using a frequency spectrum obtained from a photo under light-emitting diode illuminations emitting multi-carrier modulated signals. We utilize characteristics of a rolling-shutter camera as a frequency filter whose function depends on its shutter opening ratio. By using one test photo image, the proposed method can judge whether it was taken with an authorized or unauthorized camera. When the value of an authorized shutter opening ratio is updated periodically or randomly on an authorized camera only, it is possible to use a frequency spectrum of a photo taken by the camera as its own one-time fingerprint. Technical details of the proposed method are described and its characteristics are established through controlled and laboratory-setting experiments. The experimental results confirm that the proposed method can achieve an f1-score of 99.1% and an area under the receiver operating characteristic curve of 0.9997. Causes of correct and wrong detection results are investigated and the robustness of the proposed method is discussed using compressed and resized photo images. Issues related to limitations and deployment for real-world applications are described.