Robust SWT SVD Based Digital Image Watermarking Technique

Due to the advancement in computer technology and readily available tools, it is very easy for the unknown users to produce illegal copies of multimedia data which are floating across the Internet. In order to protect those multimedia data on the Internet many techniques are available including various encryption techniques, steganography techniques, watermarking techniques and information hiding techniques. Digital watermarking is a technique in which a piece of digital information is embedded into an image and extracted later for ownership verification. Secret digital data can be embedded either in spatial domain or in frequency domain of the cover data. In this paper, frequency domain technique is used. Here, singular value decomposition (SVD) and stationary wavelet transformation (SWT) based water marking technique is proposed for hiding watermark. The quality of the watermarked image and extracted watermark is measured using peak signal to noise ratio (PSNR). A user defined or predefined watermark can be embedded within the camera itself during capturing of the image without disturbing quality of the image. It is observed that the quality of the watermarked image is maintained. Robustness of proposed algorithm is tested for various attacks which include Salt and Pepper noise, Gaussian noise, cropping and compression. A large payload can also be embedded in this proposed algorithm.