Comparative Analysis of Digital Image Watermarking using DCT and DWT

Abstract

Watermarking is a technique to hide information into digital data and provides security against intentional and unintentional attack. It is a very important and emerging field which helps to protect ownership of digital information. Watermarking is the process of inserting or hiding information behind cover data. In this paper we discussed about two digital watermarking techniques, Discrete Cosine Transform (DCT) and discrete wavelet Transform (DWT). The parameters to test robustness and transparency of the watermarking are Peak signal to Noise Ratio (PSNR), Mean Square Error (MSE) and Normalized correlation coefficient. Also, robustness of watermarking is necessary so we tested for various attacks including Gaussian noise, salt and pepper noise, rotation and filtering. The experiment result shows that the frequency domain method is more robust against different kinds of attacks and the watermarked image has good transparency. Both techniques are implemented and result analysis has been observed.Keywords: Digital image watermarking, wavelet transform, discrete cosine transform, peak signal to noise ratio