Digital Watermarking Algorithm for Tampering Localization

Abstract

For image authentication, the competence of accurately locating tampering and ensuring security is desirable. In this paper, a novel reversible data embedding based on Integer Wavelet Transform for tamper-proof watermarks is proposed. A contentbased watermark generated from host image is embedded into the carrier. The embedded data can be retrieved and the original host image can be recovered without distortion. The difference between the extracted watermark and the watermark generated from specific coefficients representing local features is applied to localize tampers. Experimental results show that the host image can be recovered after extracting the watermark if there are no attacks. Otherwise, the tampered positions can be localized explicitly and directly in the reconstructed host image even if the watermarked image was attacked by an invisible tampering. The proposed algorithm can be used for image authentication and tampering localization without using original image and original watermark.