基于拉普拉斯金字塔的数字水印防伪技术

Digital Security Technology of Watermark Based on Laplacian Pyramid

目的为了提高数字水印的不可见性,运用拉普拉斯金字塔对原始图像进行拉普拉斯分解后使用DCT变换将水印嵌入其拉普拉斯残差图像的中高频。方法对原始图像的Y通道灰度图像进行多层拉普拉斯分解后得到第2层拉普拉斯残差图像,然后通过余弦变换将水印图像嵌入原始图像第2层拉普拉斯残差图像,最后将所有拉普拉斯残差图重建为含水印图像。结果嵌入水印图像的PSNR能够达到40.3 d B,在图像细节上有少许多噪声,并且对一定的图像攻击具有鲁棒性。结论该算法能够改善数字水印技术的不可见性。

The aim of this study was to decompose the hologram image into different frequency by Laplacian pyramid decomposition and embed the watermark into medium-high frequency coefficients of the residual image, so as to improve the invisibility of digital watermark. The second layer Laplacian residual image was obtained after multilayer Laplacian decomposition of Y components gray level image in the host image. Then the watermark was embedded into the second layer Laplacian residual image through the cosine transform. In the end, all the Laplacian residual images were rebuilt to a watermarked image. The experimental results indicated that the PSNR of the watermarked image can reach 40.3 dB with less noises in image details, at the same time, the watermarked image had good robustness against many attacks. The algorithm has better performance in improving the invisibility than before.