Adaptive image digital watermarking with DCT and FCM
Liyun Su, Hongru Ma, Tang Shifu · Wuhan University Journal of Natural Sciences · 2006
A novel adaptive digital image watermark algorithm is proposed. Fuzzy c-means clustering (FCM) is used to classify the original image blocks into two classes based on several characteristics parameters of human visual system (HVS). One is suited for embedding a digital watermark, the other is not. So the appropriate blocks in an image are selected to embed the watermark. The watermark is embedded in the middle-frequency part of the host image in conjunction with HVS and discrete cosine transform (DCT). The maximal watermark strenght is fixed according to the frequency masking. In the same time, for the good performance, the watermark is modulated into a fractal modulation array. The simulation results show that we can remarkably extract the hiding watermark and the algorithm can achieve good robustness with common signal distortion or geometric distortion and the quality of the watermarked image is guaranteed.