Watermarking technique based on transform domain for copyright protection

Watermarking is a technique to embed extra information into the content directly. Digital watermarking is embedding various information in digital content which are to be protected from illegal copying. Digital watermarking finds applications like fingerprinting, owner identification apart from the copyright protection. To embed the data into an image both SVD (Singular Value Decomposition) and DCT (Discrete Cosine Transform) have been used. In this research, a new robust watermarking scheme is proposed based on the Transform domain techniques of DCT and SVD. The DCT coefficients are mapped in a zigzag order into four quadrants after applying the DCT to original image, and SVD is applied to each quadrant. By modifying the singular value of Discrete Cosine Transformed host image then the watermark is embedded, subsequently it is modified in each area with the G quantizing value using Particle Swarm Optimization to increase the robustness and the visual quality. Watermark extraction is performed by the inversion of watermark embedding process. Experimental result is to illustrate that the proposed work able to withstand a imperceptibility as well as variety of image processing attacks.