Study and Analysis of Robust DWT-SVD Domain Based Digital Image Watermarking Technique Using MATLAB

This paper presents a robust and blind digital image watermarking technique to achieve copyright protection. In order to protect copyright material from illegal duplication, various technologies have been developed, like key-based cryptographic technique, digital watermarking etc. In digital watermarking, a signature or copyright message is secretly embedded in the image by using an algorithm. In our paper, we implement that algorithm of digital watermarking by combining both DWT and SVD techniques. Initially, we decompose the original (cover) image into 4 sub-bands using 2-D DWT, and then we apply the SVD on each band by modifying their singular values. After subjecting the watermarked image to various attacks like blurring, adding noise, pixelation, rotation, rescaling, contrast adjustment, gamma correction, histogram equalization, cropping, sharpening, lossy compression etc, we extract the originally inserted watermark image from all the bands and compare them on the basis of their MSE and PSNR values. Experimental results are provided to illustrate that if we perform modification in all frequencies, then it will make our watermarked image more resistant to a wide range of image-processing attacks (including common geometric attacks), i.e. We can recover the watermark from any of the four sub-bands efficiently.