A color image watermarking method combined QR decomposition and spatial domain

For protecting the digital copyright of color image, a color image watermarking method should have strong robustness and short running-time at same time. To achieve these two goals, an effective color image watermarking method is presented in this paper. Firstly, the element in the first row and first column of the R matrix of QR decomposition is obtained by the presented method in spatial domain. Secondly, the obtained element of R matrix is selected to protect the copyright of color image in spatial domain without the true QR decomposition. Finally, the processes of the presented watermarking technique are performed in spatial domain. In the compared experimentations, the imperceptibility of the presented method is about 40 dB, its average NC is 0.9435, its average running-time is 0.703613 s, its embedding capacity is 0.03125 bpp, and its key space is 2 138 , which proves the proposed new method has better performances in terms of the robustness and real-time feature.