Perceptual hash based blind geometric synchronization of images for watermarking

In this work, we consider the problem of blind geometric synchronization of images for watermarking. Existing solutions involve insertion of periodic templates, geometrically-invariant domains, and feature-point-based techniques. However, security leakage and poor watermark detection performance under under lossy geometric attacks are some known disadvantages of these methods. Different from above, recently a perceptual-hash-based secure and robust image synchronization scheme has been proposed. Although it has some promising results, it requires a series of heavy computations which prevents it from being employed in real time (or near real time) applications and from being extended to wider range of geometric attack models. In this paper, we focus on the computational efficiency of this scheme and introduce a novel randomized algorithm which conducts geometric synchronization much faster.