ABSTRACT

Multimedia and Internet have become our daily needs. It has become a common practice to create copy, transmit and spread digital data .It leads to unauthorized duplication problem. Digital image watermarking provides a powerful solution for this problem. Watermarking is the process of embedding a cover image in such a way that the resulting watermarked image is robust to certain distortion caused by either standard data processing in a friendly environment or malevolent attacks in an unfriendly environment . This paper presents a digital image watermarking based on two dimensional Fast Fourier Transform (FFT) and Discrete Wavelet Transform (DWT). The generalized algorithms are presented for FFT, DWT-FFT combined approach. Peak signal to noise ratio and normalized cross-correlation coefficient are computed to measure image quality for each transform. Comparative results of image watermarking using FFT and DWT-FFT are presented. Experimental results demonstrate that the proposed scheme is imperceptible and has good robustness for some common image processing operations and some attacks. The paper recommends DWT-FFT based techniques for achieving secure image watermarking.