Technical Reports
HPL-2009-373
A Practical DCT based Blind Image Watermarking Scheme for Print-and-Scan ProcessJin, Jianming; Xiong, Yuhong; Hou, Huiman
HP Laboratories
HPL-2009-373
Keyword(s): blind image watermarking, print-and-scan, information hiding, image processing, block-DCT
Abstract: Blind image watermarking technologies allow information to be embedded in common digital images and then recover from the watermarked images without the original images. However, the embedded information is often damaged after the print-and-scan process, because of the randomly added noises, the altered color, and the rotation and scaling introduced in the process. In this paper, we present a practical blind image watermarking scheme based on DCT domain which can survive from the print-and-scan process. The image is partitioned into blocks, and each block embeds one bit watermark data. Two uncorrelated pseudo random sequences are used to spread bit 0 and 1 in the middle frequency band of block-DCT spectrum respectively, which is done by adding the corresponding pseudo random sequence to the middle frequency block-DCT coefficients adaptively. The embedded bit is recovered by comparing the correlations of the modified middle frequency coefficients with each pseudo random sequence. Experiments show that the bit error ratio of watermarking is 2.26% after the print-and-scan process, which is robust enough for visual objects embedding. The robustness of the embedded data can be further improved by incorporating data error correction coding and data repetition voting techniques. In conclusion, this scheme achieves a good performance of both watermark robustness and watermark transparency for the print-and-scan process.
15 Pages
Additional Publication Information: To be published and presented at Image Processing: Machine Vision Applications III, Proceedings of the SPIE-The International Society for Optical Engineering. San Jose, CA., Vol. 7538, 2010..
External Posting Date: December 17, 2009 [Abstract Only]. Approved for External Publication - External Copyright Consideration
Internal Posting Date: December 17, 2009 [Fulltext]