Image watermarking with a directed periodic pattern to embed multibit messages resilient to print-scan and compound attacks

摘要

In this paper, we propose a blind method to embed multibit watermarks in images, robust to various attacks on geometry and print-scan process. For carrying the multibit information, a method using directed watermark patterns is proposed. A message sequence is mapped to a directional angle of a periodic pattern, which is then embedded into image blocks. In the detection, using autocorrelation function, filtering, masking, and adaptive line search with Hough transform, the alignment of the autocorrelations peaks are detected from image blocks, and interpreted as a message. The method provides a robust and blind extraction of information after a print-scan attack. Additionally, the experiments with two laser printer and two printout material show that the method is robust to compound attacks, such as Stirmark random bending, shearing, aspect ratio change, cropping, translation, or JPEG combined with print-scan.