Improved wavelet-based watermarking through pixel-wise masking

TLDR

Pixel‑wise masking that considers texture and luminance across all subbands distinguishes this method from conventional wavelet‑domain watermarking. The study proposes a wavelet‑domain watermarking algorithm that improves performance by masking the watermark based on human visual system characteristics. The algorithm embeds a pseudorandom watermark into the largest detail bands, detects it via correlation with the watermark code, and sets a detection threshold independent of the embedding energy, enabling image‑specific adaptation. Experiments and comparisons with existing wavelet‑domain techniques demonstrate the algorithm’s effectiveness.

Abstract

A watermarking algorithm operating in the wavelet domain is presented. Performance improvement with respect to existing algorithms is obtained by means of a new approach to mask the watermark according to the characteristics of the human visual system (HVS). In contrast to conventional methods operating in the wavelet domain, masking is accomplished pixel by pixel by taking into account the texture and the luminance content of all the image subbands. The watermark consists of a pseudorandom sequence which is adaptively added to the largest detail bands. As usual, the watermark is detected by computing the correlation between the watermarked coefficients and the watermarking code, and the detection threshold is chosen in such a way that the knowledge of the watermark energy used in the embedding phase is not needed, thus permitting one to adapt it to the image at hand. Experimental results and comparisons with other techniques operating in the wavelet domain prove the effectiveness of the new algorithm.