Repeating image watermarking technique by the visual cryptography

A repeating watermarking technique based on visual secret sharing (VSS) sch eme provides the watermark repeated throughout the image for avoiding the i mage cropping. In this paper, the watermark is divided into public watermar k and secret watermark by using the VSS scheme to improve the security of t he proposed watermarking technique. Unlike the traditional methods, the ori ginal watermark does not have to be embedded into the host image directly a nd, thus, it is hard to be detected or removed by the pirates or hackers. T he retrieved watermark extracted from the watermarked image does not requir e the complete original image, but requires a secret watermark. Furthermore , the watermarking technique suits the watermark with an adaptive size of b inary image for designing the watermarking system. The experimental results show that the proposed method can withstand the common image processing op erations, such as filtering, lossy compression and the cropping attacking e tc. The embedded watermark is imperceptible, and that the extracted waterma rk identifies clearly the owner's copyright.