A rotation and scaling invariant second generation watermarking scheme

In this paper, a scheme following the second generation watermarking (2GW) paradigm is proposed. The host image is decomposed with the wavelet packet (WP). The bit stream of binary watermark is coded into several patterns with salient feature, which is circular masking in this paper. These patterns are embedded into wavelet packet coefficients according to human perceptual characteristics. For the detection of watermark, the geometric distortion is calibrated for the contaminated watermarked image. A new HVS mask based on wavelet transform is proposed with consideration of local texture characteristics when embedding. Hough transform is used to detect the circular features in the WP domain. This scheme has the following characteristics: (a) robustness against the common geometric attacks (rotation, scaling, etc.) is improved significantly. (b) human perceptual characteristics are taken into consideration, therefore, the tradeoff between invisibility and robustness is improved. Results of extensive experiments indicate that this proposed scheme is significantly effective in resisting various attacks such as adding noise, rotation, scaling, JPEG compression, etc.