Design and Analysis of Digital Image Watermarking Techniques for Digital Right Management

Abstract

Digital watermarks embedded in multimedia can provide further protection in decrypted data. Objectives of this work are: (1) assessing the deficiencies of different prevalent watermarking techniques, (2) developing new schemes to remove these deficiencies of the prevalent schemes, and (3) testing and assessing the efficacy of the new developed schemes regarding protection against risks in maintaining authenticity, privacy and originality of the image and to test the scheme for safeguard against malicious tampering. This thesis focuses on developing watermarking techniques especially for medical images which have different requirements and design challenges from those for general images. First, we investigate a fragile, blind and lossless data hiding algorithm for retinal images. Second, we investigate a completely reversible, blind and lossless watermarking method for tele-ophthalmology applications with an improved imperceptibility, robustness and capacity which can effectively control the integrity and authentication issues in medical images without affecting the quality and properties of the image. Third, we investigate a zero-watermarking technique which can perfectly fulfill the non-negotiable requirement of protecting lesion of medical image. Last, we propose an innovative system of completely reversible watermarking in medical images by uniting the benefits of three conventional approaches Zero Watermarking-which ensures no loss of medical information, RONI (Region of Non-Interest) Watermarking-which ensures no tampering in Region of Interest (ROI) and Reversible watermarking: which ensures complete recovery of original image after watermark extraction. All proposed algorithms can be helpful in finding a suitable way out to address the concern of integrity control, authentication and risk of identity loss of medical images all through the transmission and while storing in large distributed databases.