An Effective Watermarking Scheme for Medical Images Using Hybrid Transform (DCT- DWT)

The growth of multimedia and communication technology has paved new ways for the storage, access and distribution of medical data in digital format. Conversely, these developments have introduced new risks for unsuitable deployment of medical information flowing in open networks, provided the effortlessness with which digital content can be manipulated. It is renowned that the integrity and confidentiality of medical data is a serious topic for ethical and legal reasons. Medical images need to be kept intact in any condition and prior to any operation as well need to be checked for integrity and verification. Watermarking is a budding technology that is capable of assisting this aim. In recent times, frequency domain watermarking algorithms have gained immense importance due to their widespread use. This paper describes an effective frequency domain watermarking scheme for verifying the integrity and authenticity of medical images. The proposed watermarking scheme makes use of hybrid transform, which combines Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT). Initially, the original image is decomposed using hybrid transform. Subsequently, the watermark embedding and extraction are performed in frequency domain using the presented scheme. The proposed watermarking scheme is blind, so the watermark extraction doesn’t require the original image or any of its characteristics. The effectiveness of the proposed watermarking scheme is demonstrated with the aid of experimental results.