Research on the graying methods for QR images and their application to anti-counterfeiting watermarking

摘要

Two kinds of graying methods for QR binary images are proposed in this paper, which make transform domains watermarking methods possible, greatly increase the watermarking capacity and improve the anti-counterfeiting performance of the QR barcode based on the digital watermark technique. The graying extent for the QR binary image is determined by the graying threshold, which can be selected according to its specific application. Based on the graying algorithm, the anti-counterfeiting QR barcode watermarking scheme in the transform domain is proposed. In the proposed scheme, classical transform domain watermarking algorithms such as DWT-based watermarking and DCT-based watermarking methods are introduced to QR barcode anti-counterfeiting. The experiments indicate that the watermarking capacity as well as the recognition rates of transform domain watermarking algorithms with the proposed graying methods are far better than those of spatial domain watermarking algorithms.