Abstract:

A novel watermarking algorithm for digital images based on DWT,DCT and SVD is proposed in this paper.First, according to the decomposition criteria proposed in this paper,we apply a four layer DWT on the original image,and choose the lowfrequency subimage and the three highfrequency subimages of the fourth layer.Similarly,we apply DWT to the watermaking image and get the lowfrequency subimage and the three highfrequency subimages.Then,by using DCT,SVD and the decomposition criteria proposed in the paper,we embed the lowfrequency subimage and the three highfrequency subimages obtained from the watermarking image into those of the original image adaptively.Finally the watermarked image is obtained after the inverse SVD,DCT and DWT.In the scheme,scrambling technology is used for preprocessing and postprocessing the watermarking image's information hiding,and it also well guarantees the safety of data.Experimental results demonstrate that this method is robust.

Key words: SVD;watermarking;robust;DWT