Blind image watermarking scheme in DWT-SVD domain

Discrete Wavelet Transform (DWT) is widely applied to image watermarking applications because it decomposes a cover image into spatial domain as well as frequency domain simultaneously. Also, Singular Value Decomposition (SVD) is suitable for watermarking applications since some largest singular values are sufficient to embed watermarks instead of using all singular values. We propose a hybrid blind watermarking scheme based on DWT and SVD for image data. The proposed scheme embeds watermarks by modifying log-scaled singular value of selected coefficients of all sub-bands. We have found two properties to be robust against malicious attacks commonly happened to images. We performed experiments to prove that the proposed scheme has the robustness against to a wide range of attacks such as JPEG compression, Gaussian noise addition, median filtering, blurring, histogram equalization, gamma correction, rescaling, shift, and rotation.