Comparative analysis of conventional 2-level DWT and color plane watermarking for telemedicine applications

In telemedicine applications, there is a huge demand for sharing of digital images among specialist and hospitals for better and more accurate diagnosis. Medical image watermarking is a powerful tool that can be used as a medium for sharing medical images among the specialists. Therefore, medical image watermarking cannot be compromised by the quality of image, as well as it is important that image is flawlessly retrieved without the risk of error after image decomposition. In this paper a comparative analysis of conventional 2-level DWT medical image watermarking technique and color plane watermarking technique is proposed. The performance of watermarked image is evaluated by Peak Signal to Noise Ratio (PSNR). The PSNR values of both the technique are compared with varying scaling factor alpha. Higher the PSNR, better is the quality of watermarked image. It is found that a maximum of 73.6239 dB PSNR is observed in color plane watermarking technique as compared to conventional 2-level DWT based watermarking, which is having a PSNR of 56.1993 dB at the same scaling factor. The security of the watermark is enhanced by Arnold's Scrambling method and the robustness is evaluated by Correlation coefficient parameter. The performance of the proposed watermarking system is evaluated against common attacks. It is further suggested that, especially for medical images, watermarking should be done in any of the color plane (R, G or B) instead of doing watermarking on the entire image so as to achieve high PSNR for better reconstruction of watermarked medical image.