Image watermarking via separable moments

The use of image moments as host coefficients constitutes one of the hot topics in image watermarking field due to their robust behavior. Recenlty, a new approach called separable moments (SMs) has been introduced representing an image as combinations of different orthogonal polynomials that generate a series of new moment families. The scope of the present work is to introduce the specific transformations to the image watermarking field by evaluating their security capability under a wide range of common signal processing and geometric attacks. Furthermore, their ability of carrying large binary watermark messages is also examined. The performance of the proposed moment families is evaluated by a comparison to the original moments and a state-of-the-art method. The experimental results justified that a number of the studied transformations outperforms the benchmark method and occasionally the original moment families. Moreover, specific separable moment families are free of instabilities to the higher order coefficients where the extra watermark information is carried. A significant conclusion lies on the adoption of properties (locality, stability) between the generated separable moment families that lead to the enhancement of the basic watermarking requirements (robustness, imperceptibility and capacity) of the proposed watermarking method. The present work justifies that discrete orthogonal SMs constitute a new attractive transformation for the image moment-based watermarking field.