Robust image watermarking algorithm using chaotic sequences

Abstract

This article presents a robust image watermarking scheme that provides high robustness and imperceptibility based on an innovative application of chaotic bits and error-correcting codes. The bits embedded in the image are the parity bits of an error-correcting code whose information sequence is formed by combining the watermark bits with chaotic bits generated from a secret key known to all legitimate users. Therefore, a part of the codeword is perfectly known to these users in the watermark extraction processing regardless of the strength of an attack. Thus, the error-correcting code capability is employed in recovering the watermark bits, improving the robustness of the method. The parity bits are embedded at specific frequencies of the discrete cosine transform and a parameter controls the compromise between robustness and imperceptibility. The proposed method is tested against several signal processing and geometric attacks, and comparison results reveal that it outperforms the existing schemes.