Cascaded Algorithm:DWT-DCT-SVD in Watermarking

Watermarking is the process of embedding data into multimedia element as an image, audio or video file for the purpose of authentication. This embedded data can later be extracted from or detected in the multimedia for security purposes. In this paper, we propose a watermarking based on combining DWT-DCT-SVD. In this technique DWT is used to decompose the color images into various frequency and time scale. Block DCT is applied on DWT coefficients of various frequencies to provide high level of robustness. DCT transformed blocks of size 4x4 are further decomposed using dual SVD technique to get singular values in which watermark is to be hidden. This method of watermarking is found to be robust and the visual watermark is recoverable without any reasonable amount of distortion even in case of attacks. Thus the method can be used to embed copyright information in the form of a visual watermark. Algorithm is tested using Lena test image in RGB and YIQ color model.