Photo Response Non-Uniformity (PRNU) noise obtained from images or videos is used as a camera fingerprint to attribute visual objects captured by a camera. The PRNU-based source attribution method, however, fails when there is misalignment between the fingerprint and the query object. One example of such a misalignment, which has been overlooked in the field, is caused by the in-camera resizing technique that a video may have been subjected to. This paper investigates the attribution of visual media in the context of matching a video query object to an image fingerprint or vice versa. Specifically this paper focuses on improving camera attribution performance by taking into account the effects of binning, a commonly used in-camera resizing technique applied to video. We experimentally show that the True Positive Rate (TPR) obtained when binning is considered is approximately 3% higher.

Photo Response Non-Uniformity (PRNU) based camera attribution is an effective method to determine the source camera of a visual object (an image or a video). To apply this method, images or videos need to be obtained from a camera to create a “camera fingerprint” which then can be compared against the PRNU of the query media whose origin is under question. The fingerprint extraction process can be time consuming when a large number of video frames or images have to be denoised. This may need to be done when the individual images have been subjected to high compression or other geometric processing such as video stabilization. This paper investigates a simple, yet effective and efficient technique to create a camera fingerprint when so many still images need to be denoised. The technique utilizes Spatial Domain Averaged (SDA) frames. An SDA-frame is the arithmetic mean of multiple still images. When it is used for fingerprint extraction, the number of denoising operations can be significantly decreased with little or no performance loss. Experimental results show that the proposed method can work more than 50 times faster than conventional methods while providing similar matching results.

Given a query image or video, or a known camera fingerprint, there is a lack of capabilities for fast identification of media, from a large repository of images and videos, that match the query fingerprint. This work introduces a new approach that improves the computation efficiency of pairwise camera fingerprint matching and incorporates group testing to make the search more effective. More specifically, we jointly leverage the individual strengths of composite fingerprints and fingerprint digests in a novel manner and design two methods that are superior to existing approaches. The results show that under very high-performance requirements, where the probability of correct identification is close to one with a false-positive rate of zero, the proposed search methods are 2-8 times faster than the state-of-art search methods.

Photo response non-uniformity (PRNU) noise-based source attribution is a well-known technique to verify the camera of an image or video. Researchers have proposed various countermeasures to prevent PRNU-based source camera attribution. Forced seam-carving is one such recently proposed counter forensics technique. This technique can disable PRNUbased source camera attribution by forcefully removing seams such that the size of most uncarved image blocks is less than 50 × 50 pixels. In this paper, we show that given multiple seamcarved images from the same camera, source attribution can still be possible even if the size of uncarved blocks in the image is less than the recommended size of 50 × 50 pixels. Theoretical analysis and experiments with multiple cameras demonstrate that the effectiveness of our scheme depends on the number of seams carved from an image and the randomness of the seam positions.

Photo Response Non-Uniformity (PRNU) noise based source attribution is a well known technique to verify the source camera of an anonymous image or video. Researchers have proposed various counter measures to PRNU based source camera attribution. Forced seam-carving is a recently proposed counter forensics measure that was proposed to defeat PRNU based source attribution by disturbing the alignment of PRNU noise patterns. This paper shows that given a multiple number of seam-carved images, source attribution can still be reliably made even if the size of a non-carved image block is less than the recommended size of 50×50.