... addition IV CONCLUSION In this paper, we have made a contribution to a multiple non-blind watermarking scheme based on the DWT The proposed scheme consists in applying the DWT to the gray scale ... “Tatouage d’images couleur additif : vers la selection d’un espace d’insertion optimal,” Coresa03, 2003 S Rastegar, F Namazi, K Yaghmaie and A Aliabadian, “Hybrid watermarking algorithm based on ... four extracted watermarks are, afterwards, compared to the original watermark to check the watermark presence in the attacked image For objective examination, they calculate the similarity ratio...