A blind digital watermarking for color medical images based on PCA

In this paper, we propose a new robust digital image blind watermark scheme that is used to protect color medical images. In this scheme, K-L transform is applied to an RGB medical image and the binary watermark is embedded into low frequency sub-band of DWT of the principal component of medical images. The embedding positions are chosen according to the human visual system (HVS). The embedding method is based on the relationship between center coefficients and the mean values of the nearest neighborhood coefficients. The watermark is extracted from the watermarked image only according to the relationship. The experimental results show that the proposed algorithm is robust, imperceptible and practicable.