A Study of Dct-svd Based Robust Watermarking Scheme

In this paper, the authors have presented the study of digital watermarking scheme which employs both the Discrete Cosine Transform (DCT) and the Singular Value Decomposition (SVD). The study discuss that how an original greyscale image can be secured by robust digital watermarking. In this paper it has been discussed how block based DCT and SVD transformation together can form a hybrid watermark which has a very good quality of withstanding quality against various noise. Block based DCT transform the whole image into several blocks based on their frequency range and gives a frequency spectrum. At the middle band of spectrum watermark is embedded which gives less chance of distortion on cover image as well as more withstanding capability against compression attack.SVD transformation on reduced image make it more robust and less visible. Various results of this technique shows it’s success as a hybrid approach than a normal one. General Terms Multimedia Security