Reliable and Fast Forgery Detection using FINE GRAINED approach

Forensic science encompassing the recovery and investigation of material found in digital devices, often in relation to computer crime. A digital forensic investigation commonly consists of 3 stages: acquisition or imaging of exhibits, analysis, and reporting. Previously, it is able to detect tampered images at high accuracy based on some carefully designed mechanisms,localization of the tampered regions in a fake image still presents many challenges, especially when the type of tampering operation is unknown. Later on, necessary to integrate different forensic approaches in order to obtain better localization performance. However, several important issues have not been comprehensively studied, to improve/readjust proper forensic approaches, and to fuse the detection results of different forensic approaches to obtain good localization results. In this paper, we propose a framework to improve the performance of forgery localization via implementing tampering possibility maps along with fusion based technique. In the proposed framework, we first select and improve existing forensic approaches, i.e., copy-move forgery detector and statistical feature based approach, and then improve their results to obtain tampering possibility maps

Print-Scan Resilient Text Image Watermarking Based on Stroke Direction Modulation for Chinese Document Authentication

Print-scan resilient watermarking has emerged as an attractive way for document security. This paper proposes an stroke direction modulation technique for watermarking in Chinese text images. The watermark produced by the idea offers robustness to print-photocopy-scan, yet provides relatively high embedding capacity without losing the transparency. During the embedding phase, the angle of rotatable strokes are quantized to embed the bits. This requires several stages of preprocessing, including stroke generation, junction searching, rotatable stroke decision and character partition. Moreover, shuffling is applied to equalize the uneven embedding capacity. For the data detection, denoising and deskewing mechanisms are used to compensate for the distortions induced by hardcopy. Experimental results show that our technique attains high detection accuracy against distortions resulting from print-scan operations, good quality photocopies and benign attacks in accord with the future goal of soft authentication