Akademik Veri Yönetim Sistemi
Lecture Notes in Electrical Engineering, ss.147-159, 2009 (SCI-Expanded)
This study aims to develop two optimal watermarking techniques based on SVD and DWT-SVD domain for grey-scale images. The first one embeds the watermark by modifying the singular values of the host image with multiple SFs. In the second approach, a hybrid algorithm is proposed based on DWT and SVD. Having decomposed the host image into four bands, SVD is applied to each band. Then, the same watermark is embedded by modifying the singular values of each band with different SFs. Various combinations of SFs are possible, and it is difficult to obtain optimal solutions by trial and error. Thus, in order to achieve the highest possible transparency and robustness, optimization of the scaling factors is necessary. This work employs DE to obtain optimum SFs. DE can search for multiple solutions simultaneously over a wide range, and an optimum solution can be gained by combining the obtained results appropriately. Experimental results of developed techniques show both the significant improvement in transparency and the robustness under attacks. © 2009 Springer Netherlands.