المجلة الدولية للعلوم والتقنية

Digital watermarking is one of the data-hiding methods, which embeds the watermark data into the digital multimedia content. The two important requirements for watermarking methods are imperceptibility and robustness. This paper presents a comparative study of transformation techniques, which are discrete wavelet transform, discrete cosine transform, and discrete Fourier transform that have been used in the field of digital image watermarking. The paper uses the peak signal-to-noise ratio measure as a basic metric for comparing the transparency attribute of the watermarking methods. Whereas the correlation coefficient metric is adapted to test the resistivity of the watermarking methods to different attacks. Moreover, the paper examines the combination of the singular value decomposition technique with the other transformation techniques in terms of exploring whether the combination will enhance the result or not. The experimental results show that the discrete wavelet transform and the discrete wavelet transform combined with the singular value decomposition outperform the state-of-the-art method and enhance both the imperceptibility and the robustness with less computational time when the watermarked image is not subjected to any attack. Keywords—Image watermarking; robustness; imperceptibility; singular values decomposition; discrete wavelet transform; discrete cosine transform; discrete Fourier transform