Blind watermarking via low frequency component modification

In this paper we present a blind low frequency watermarking scheme. We obtain a robustness improvement to most common image processing operations by embedding the watermark in the approximation image of the original image. In order to embed the watermark with minimal loss in image fidelity, the watermark strength is modulated according to the local image characteristics. We generate a visual mask based on the texture, edge and luminance masking effects of the human visual system. Watermark detection is done without use of the original image. Experimental results show that the proposed technique is robust against most common image processing operations.