多尺寸普适的抗印刷扫描水印算法

目的为了赋予固定尺寸水印自适应不同尺寸宿主图像的尺寸普适性,提出一种多尺寸普适的抗印刷扫描水印算法。方法对宿主图像进行裁剪、分层、分块获得图块,计算每个图块的最大奇异值,取最大奇异值前九的图块组成拼接图像,结合水印嵌入算法在拼接图像中抽取获得待嵌图像,将制成全息图的水印嵌入待嵌图像的DWT域内。结果实验表明,将固定尺寸水印嵌入不同尺寸宿主图像后,随着宿主图像尺寸的增加,水印图像的不可见性明显提高,并且经历模拟印刷扫描可顺利提取水印。结论该算法不仅可以赋予固定尺寸水印适应不同尺寸宿主图像的普适性,且提升了水印嵌入后的不可见性,对印刷扫描具有较好的鲁棒性,为数字水印在印刷防伪领域的应用研究提供了新思路。

Universal Multi-size Watermarking Algorithm for Print-and-Scan Process

The work aims to propose a universal multi-size watermarking algorithm for anti-print-scan process to provide a universality that helps fixed-size watermarks to adapt to host images of different sizes. Host image was divided into layers and blocks to obtain the blocks images and calculate the maximum SVD values of each blocks images. The blocks with the top nine maximum SVD value were selected to form the await-embed image. The holographic watermark was embedded into DWT domain of the await-embed image. The experiments showed that, after embedding the fixed watermark into the host image of different sizes, the invisibility of the watermark image was significantly improved with the increase of the host image size, and the watermark could be extracted smoothly after simulated anti-print-scan process. This algorithm could not only provides the universality that helps fixed-size watermarks to adapt to host images of different sizes, but also improves the invisibility of the watermark after embedding. It shows good robustness to print-scan process, and provides a novel method for the application of digital watermark in anti-counterfeiting printing.