Fragile and blind watermarking technique based on Weber´s law for medical image authentication

In developing countries such as India, transmission of medical images over the network is essential for providing health services to rural/remote population. During this transmission, a small distortion in the medical image may lead to wrong conclusions. Thus, arises the need to embed some authentication information in medical images to authenticate transmitted image. In this study, a blind and fragile watermarking technique based on Weber´s law is proposed. Here, fragile watermark is inserted by quantising intensity of selected pixels in a medical image. As the proposed technique is fragile, it detects even a small change made to watermarked image and locates blocks where distortion has been made. Besides being able to detect all malicious changes that affect the quality of watermarked image, it is tolerant to image compression, which is essential to transmit images over the network. The proposed technique is highly imperceptible as the watermark is inserted by modifying intensity of dark pixels selected using Weber´s law. An extension of the proposed technique is also given to enhance its capacity. Experimental results on standard medical image database prove the efficacy of the proposed method over existing works.