Embedding an identifying data into digitized music, video or image is known as digital watermarking. Reversible image watermarking is used to embed and extract hidden data to and from the watermarked image without any distortion to the original. In this paper, we propose an improved reversible watermarking scheme using an additive interpolation technique, which increases embedding capacity with inconspicuous degradation of image quality. Unlike former watermarking schemes, a new interpolation-error is exploited to embed bit "1" or "0" using additive expansion or leaving it unchanged. Consequently, original image is remained at a high level of quality. Moreover, a cryptographic scheme is utilized to prevent an adversary from accessing embedded data. Therefore, achieving watermarked data will not be straightforward. The experimental results show that the proposed method in addition to greater embedding capacity, has higher image fidelity compared to previous schemes.
Digital Watermarking; Reversible Image Watermarking; Additive Interpolation-Error Expansion.