A novel image digital watermark algorithm with weighted fractional calculus based on wavelet coefficients

A novel digital watermark algorithm, based on fractional calculus and wavelet transform, is proposed in this paper. It makes full use of the characteristic of the high sensitive fractional order. The algorithm makes sinusoidal signal by fractional Cauchy formula with two differential orders. The sampled signals of the differential signals were superimposed as the pseudo-random sequence which is used to scramble the watermark. By exchanging the high-frequency coefficients of the carrier image, the scrambled watermark was embedded into the carrier image. Experimental results show that this novel algorithm is robust to a number of regular geometric attacks and many image processing operations. The new method given in this paper has a good performance on both robustness and invisibility.