Abstract: Last few years digital watermarking has facilitated the protection of copyright information through embedding the hidden information into the digital content. Digital image watermarking is one such the technology that has been developed to protect digital images from illegal manipulations. In this paper a new SWT-SVD semi-blind composite images watermarking algorithm that is robust against various attacks is presented .We use SWT transform to obtain 4-diffirent frequency images. Then we apply SVD on each subsection to modifying their singular value, on the basis of MSE & PSNR values Experimental evaluation demonstrates that proposed algorithm is able to withstand variety of attacks as Salt & Pepper noise, Rotation, Median filter, Vertical Mirroring, Horizontal Mirroring, Gaussian noise, Cropping, Contrast etc. Watermark is recovered efficiently.

Keywords: Copyright protection, Blind watermarking, SWT (stationary wavelet transform), Singular value decomposition (SVD), MSE (mean square error), PSNR (peak signal to noise ratio).