An Overview of Transform Domain Robust Digital Image Watermarking Algorithms

Internet and Multimedia technologies have become our daily needs. Hence it has become a common practice to create copy, transmit and distribute digital data. Obviously, it leads to unauthorized replication problem. Digital image watermarking provides copyright protection to image by hiding appropriate information in original image to declare rightful ownership. Aim of this paper is to provide complete overview of Digital Image watermarking. The study focuses on quality factors essential for good quality watermarking, Performance evaluation metrics (PSNR and Correlation Factors) and possible attacks. Overview of several methods with spatial and Transform Domain watermarking is done with detail mathematical formulae, their implementations, strengths and weaknesses. The generalized algorithms are presented for DWT, CDMA based, DCT-DWT combined approach. The Ridgelet Transform is also introduced. Comparative results of Digital Image Watermarking using LSB, DCT and DWT are also presented. The paper recommends DWT based techniques for achieving Robustness in Digital Image Watermarking.