Digital Image Watermarking using DCT and SVD

Abstract

Watermarking plays a pivotal role in today's age of multimedia to combat with piracy related issues. Being a technology that provides the capacity to hide information, digital watermarking attracted more attention in copyright protection. Embedding data into a multimedia element such as an image, audio or video file for copyright or authentication purpose is known as Watermarking. In this paper, a watermarking algorithm for digital images using Singular Value Decomposition (SVD) and Discrete Cosine Transform (DCT) is proposed. The DCT is preferred for image processing for lossy compression because it has a strong "energy compaction". On calculating SVD of the image, the singular values obtained contains properties which on altering do not affect the image visually. The host image is divided into blocks processed upon and then combined again to finally get the watermarked image. Using the inverse DCT the watermark can be extracted back from the image