A perceptual pyramidal watermarking technique
This paper presents a new perceptual image watermarking scheme based on the Laplacian pyramid (LP) decomposition and a visibility map constructed using a human visual contrast model. This map is computed of each level of the pyramid in order to determine the auspicious regions for embedding the watermark. The spread spectrum technique is used to embed the watermark in some levels of the LP. The watermarked image is then constructed from the Laplacian images. The algorithm performances are evaluated in terms of watermark invisibility, using an objective image quality perceptual measure, the structural similarity index measure (SSIM), and robustness to different attacks of Stirmark such as Jpeg compression, low-pass filtering, additive noise and cropping.