Quickly tracing detection for spread spectrum watermark based on effect estimation of the affine transform

Recently, watermarking synchronization and spread spectrum watermarking schemes have become two interesting, new focuses of study. In this paper, we propose a method based on the synchronization pre-estimation in order to resist geometric attacks. First, we utilize the global features by testing them against translation, rotation and scaling, and present a simple method to estimate the geometric transform kernel of the two-dimensional gray image. Maps, applying some correlative barycenters to the original are produced that can accurately reflect the affine transform feature of the image. Furthermore, unknown variables existing in the kernel of the transform are calculated. Secondly, the watermark is directly embedded in the spatial domain. Watermarking tracing is well performed on the watermarked image instead of performing an inverse geometrical transform on it. Experimental results show that the proposed scheme can work well under several kinds of geometrical attacks.