An effective telemedicine security using wavelet based watermarking

Telemedicine enables expert diagnosis and better healthcare access to distant patients especially in remote or rural areas by allowing the transmission of medical images through telecommunication. Privacy of data being transmitted and the underlying technologies raise issues related to security. The paper proposes an algorithm for digital watermarking of medical images to ensure secure and confidential telemedicine diagnosis. In the proposed algorithm, medical images are embedded as watermark into a special cover image. In this process, the cover image is transformed by discrete wavelet transform and the LL sub-band obtained, is then transformed by discrete cosine transform. Watermark generation and embedding is performed by modifying the transformed coefficients of watermark and cover image by varying the value of scaling factor. Finally inverse discrete cosine and discrete wavelet transforms are applied on modified sub-bands to obtain the watermarked image. Watermark extraction is done using an extraction algorithm. Various quality parameters have been used to test and evaluate the performance of the proposed method for varying scale factors and different set of images. PSNR value for watermark and extracted watermark image is found in the range of 33.45 dB to 40.15 dB.