Digital image watermarking for tele-nuclear medicine images

Tele-Nuclear Image watermarking is not only for authentication, but also for nuclear images protection against malicious intentions to change or even use it for other person for any reason. Nuclear images are low resolution images so they have special requirements for image watermarking as watermarked images should not differ from their original images because of the clinical reading of the images. In this paper implementation of three different watermarking algorithms in the frequency domain will be presented. The first algorithm is based on the Discrete Cosine Transform (DCT), the second one is based on the Discrete Laguerre Transform (DLT) and the third algorithm is based on the Discrete Tchebichef Transform (DTT). Embedding the watermark is done by modifying the coefficients of the middle frequency band within region of non-interest (RONI) so that the visibility of the image and diagnosis capability will not be affected and the watermark will not be removed by compression. All schemes are tested using medical images and the simulation results are compared and the comparison shows that the best scheme is that based on using DTT.