  The principle of Photo Response Non Uniformity (PRNU) is often exploited to
deduce the identity of the smartphone device whose camera or sensor was used to
acquire a certain image. In this work, we design an algorithm that perturbs a
face image acquired using a smartphone camera such that (a) sensor-specific
details pertaining to the smartphone camera are suppressed (sensor
anonymization); (b) the sensor pattern of a different device is incorporated
(sensor spoofing); and (c) biometric matching using the perturbed image is not
affected (biometric utility). We employ a simple approach utilizing Discrete
Cosine Transform to achieve the aforementioned objectives. Experiments
conducted on the MICHE-I and OULU-NPU datasets, which contain periocular and
facial data acquired using 12 smartphone cameras, demonstrate the efficacy of
the proposed de-identification algorithm on three different PRNU-based sensor
identification schemes. This work has application in sensor forensics and
personal privacy.
