Histogram-oriented watermarking algorithm: colour image watermarking scheme robust against geometric attacks and signal processing

Developing a robust method of image watermarking that resists rotation, scaling and/or translation transformations is widely considered to be a more challenging task than developing a method resistant to other attacks. Altering the orientation or size of the image, even only slightly, reduces the receiver's ability to retrieve the watermark. Protecting against both geometric distortion and signal processing with blind detection is even more problematic. This investigation proposes a novel approach, based on the properties of histograms, to measure the numerous global features of all pixels in a cover image and to construct the three-dimensional feature space. The feature space is dynamically. partitioned to identify several blocks used to embed the watermark. One feature of the pixels is modified to form a specially distributed histogram for embedding the watermark in a blind digital watermarking method that can be applied to colour images. Experimental results demonstrate the robustness of the proposed method against common geometric attacks and signal processing.