Secure self-recovery watermarking scheme for error concealment and tampering detection

Abstract

Background: In this paper, we present a method for protecting and restoring lost or tampered information in images or videos using secure watermarks. The proposed method consists of a combination of techniques that are able to detect image and video manipulations. Contrary to most existing watermarking schemes, the method can identify the exact position of the tampered region. Furthermore, the method is capable of restoring the manipulated information and retrieve the original content. This set of capabilities make it possible to use the proposed method in error concealment and digital tampering applications. Methods: The proposed method is employed as both an error concealment algorithm and a tampering detection algorithm. The proposed method is divided into two stages. At the encoder side, the method generates a binary version (watermark) of the original picture (image or video frame) using a halftoning technique. Then, a quantization index modulation technique is used to embed this watermark into the protected picture. At the decoder side, after the lost or tampered regions are identified, the original content is recovered by extracting the watermark corresponding to the affected areas. An inverse halftoning algorithm is used to convert the dithered version of the picture into a good-quality multi-level approximation of the original content. Results: First, we test the method in error concealment applications, using a set of still images and H.264 videos. Then, we test the proposed method for tampering detection and content retrieval applications, again considering both images and videos. We compare the proposed method with several other several state-of-the-art algorithms. The results show that the proposed method is fast, robust, and accurate. Conclusions: Our results show that we can use a single approach to tackle both error concealment and tampering detection problems. The proposed method provides high levels of security, high detection accuracy, and recovery capability, and it is robust to several types of attacks.