Fragile Watermarking for Tamper Localization and Self-Recovery Based on AMBTC and VQ

Abstract

Digital images have unique features that include being both easily transmittable over the Internet and being easy to tamper. With the advancement of digital processing techniques and an increasing number of valuable digital images being transmitted via the Internet, image authentication has been made more crucial than ever. In this paper, we present an image authentication scheme with tamper localization and self-recovery using fragile watermarking. We embed the fragile watermarks consisting of the authentication code and the recovery information onto the image to verify its integrity. The proposed fragile watermarking scheme can authenticate the image without accessing the original image, localizing the modifications as well as verifying the integrity, and even reconstructing the tampered regions. We use an AMBTC compressed code as the authentication code to minimize the distortion introduced by embedding. To reduce the blocking effect that occurs in the reconstructed image, a VQ compressed code is applied instead of the average intensity as the recovery information. Several representative test images and 200 different test images were randomly selected from BOWS to examine the performance of the proposed scheme. Experimental results confirm that the proposed scheme can effectively resist a cutting attack and a copy-paste attack while retaining the high accuracy of tamper localization. The average TPR and average FTP rate were around 97% and 0.12%, respectively, while maintaining the image quality of the watermarked image and restoring the image at up to 48 dB and 39.28 dB, respectively.