Digital image Watermarking using Two Dimensional Discrete Wavelet Transform, Discrete Cosine Transform and Fast Fourier Transform

Abstract—In digital watermarking, a watermark is embedded into a cover text in such a way that the resulting watermarked signal is robust to certain distortion caused by either standard data processing in a friendly environment or malicious attacks in an unfriendly environment. This paper presents a digital image watermarking based on two dimensional discrete cosines transform (DCT2), two dimensional discrete wavelet transform (DWT2) and two dimensional fast Fourier transform (FFT2). Signal to noise ratio (SNR), peak signal to noise ratio (PSNR) and weighted peak signal to noise ratio (WPSNR) are computed to measure image quality for each transform. We present traces of original and watermarked images. From traces we observe that we get good SNR, PSNR and WPSNR with DCT2.