Source Camera Forensics Of Printed Image Based On Highlight Removement

As a kind of generated evidence, photo becomes more and more important in the judicial system and the criminal investigation. It usually has two forms, digital image and printed image, when delivered to court. Before the court receives the photo as evidence, its authenticity and source need to be identified. For this application background, scholars in the field of image forensics have been considered the digital image camera source identifying as an important research direction. But for printed photos, there are few findings come out.In fact, we cannot obtain the original digital image in many cases. For example, provider only has the print version of the digital image with the original image deleted or the digital image delivered it is a recaptured image. Therefore, how to ensure the authenticity of these images and the reliability of the source becomes a new problem need to address for the urgent justice and social stability. In this paper, we will research the print-scanned image forensics technology, and main works are summarized as follows:(1) Proposed a print-scanned image source identification method based on Pattern Noise.In this paper, the traditional source of digital image forensics technology has been studied first. Then we introduced the imaging system of camera and the influences bring to the generated image by imaging device and processing operations in detail. Camera sensor Pattern Noise has higher differentiation of different cameras in digital image sources forensics. Through the comparison, we choose a filter which can ensure remaining the least information of original image to extract noise. At last, for the geometric distortion introduced by print-scan process, we proposed a print-scanned image source identification method based on Pattern Noise. Using this method, the average identification accuracy rate of test images reaches to 76.8%, which improves 5% compared with Fridrich's method. And the method can also reach the stable test results against the rotation, scale and cut introduced by the recapturing process.(2) Proposed a source camera identification method of print-scanned digital image based on highlight removement.Through the comparison and the analysis of the experiment before, we find that the failure images usually have visible highlight which could be the reason caused the lower result. In order to verify this hypothesis and solve the problems found in experiments, we analyze the generation of highlight. Using DR model and Specular-diffuse reflection, we separate specular reflection components and diffuse components of the image. Experiment results show that this is an effective method for source camera identification with less restrict, the average accuracy on distinguishing four cameras of print-scanned images improved to 84.3%...