Geometrically Resilient Digital Image Watermarking by Using Interest Point Extraction and Extended Pilot Signals

A feature-based digital image watermarking scheme is proposed to resist geometrical transformations. Such interest point extraction as scale-invariant feature transform is applied to form the invariant regions for signal embedding. Along with the watermark, the pilot signal used for synchronized detection will also be embedded to help to determine larger areas for improving the payload of watermarking and/or increasing the confidence of watermark detection. Both embedded signals are weighted by the just noticeable difference of Watson´s perceptual model to meet the requirement of invisibility. In the detection phase, after the same interest point extraction, synchronization can be achieved via adjusting the related affine parameters of grids on the investigated image to detect the possible hidden pilot signal so that the watermark can be successfully retrieved afterward. Experimental results show the feasibility of the proposed method.