Multipurpose Blind Watermarking Algorithm for Color Image Based on DWT and DCT

In this paper, a multipurpose blind watermarking algorithm for color image based on discrete wavelet transform (DWT) and discrete cosine transform (DCT) is proposed according to the lack of multipurpose blind watermarking algorithm. In this algorithm, the robust watermark and semi-fragile watermark are embedded using the thought of dither modulation (DM) and the method of spread transform dither modulation (STDM) respectively. Simulation results demonstrate the quality of the watermarked image is good, the robust watermark has certain robustness for common attacks, the semi-fragile watermark has certain robustness to the common attacks and can locate well for the familiar attacks.