Digital Image Watermarking: A Review of SVD, DCT and DWT Based Approaches

Abstract. This paper presents digital image watermarking and review of five recently proposed ap-proaches. These approaches are based on Singular Value Decomposition (SVD), Discrete Wavelet Trans-form (DWT) and Discrete Cosine Transform (DCT). The approaches include watermarking schemes based on SVD and DWT or DCT, that modify the singular values of four bands (data sets), derived from the cover image using transform, with the singular values of watermark. We describe all the approaches pointing out their strengths and weaknesses. We further suggest an extension to the existing schemes. In the proposed work, we first decompose the cover image into bands (data sets) using DWT. These data sets are then divided into non-overlapping blocks. The singular values of each block are finally modified in a controlled manner using the singular values of watermark matrix. The partitioning of the data sets into non overlapping blocks and subsequent modification of singular values of each block make the wa-termark more robust against the various attacks as the results reveal. An experimental comparison with the existing schemes has also been carried out