基于小波多分辨率分解的数字图像水印算法

鉴于小波变换的多分辨率分析与人眼的视觉特性(HVS:Huma Visual System)相一致,提出了一种基于小波变换多分辨率分解的鲁棒水印算法.为确保数字水印的安全性,该算法在数字水印嵌入之前对水印进行了预处理.然后根据高、低频分量的特点,按照人眼视觉系统的要求选择适当的嵌入位置.实验结果表明,该水印算法很好地保证了数字水印的鲁棒性和透明性之间的统一,对剪切、压缩和锐化等图像处理均具有很强的抵抗力,与DCT(Discrete Cosine Transform)算法相比较,鲁棒性能提高了近1倍,这表明该算法是一种行之有效的水印算法.

Algorithm of Digital Image Watermarking Based on Wavelet Multi-resolution Transform

As a new technique to provide copyright protection for digital media, digital watermarking has drawn extensive attention recently. An algorithm of digital watermark based on the discrete wavelet multi-resolution transform is proposed. To ensure the security, the watermark is rotated and scrambled before embedding, and we can get a private key using filter banks in the process. Then according to the different characteristics of the high and the low frequency components of the wavelet coefficients of the original image, we select the proper position to embed the watermark. The experimental results demonstrate a better unification between robustness and invisibility. Moreover, experimental results have proved that the method is robust enough to some image proass such as cropping. compression and sharpening ets. Compare with the algorithm of DCT, the robustness was creased about a times.