一种基于DWT的彩色图像数字水印算法

本文提出了一种基于离散小波变换（DWT）的彩色图像数字水印算法，算法选择彩色图像的YIQ色彩空间的Y分量嵌入水印，利用人类视觉系统（HVS）的特性，定义视觉掩蔽函数，将二值图像加密后自适应地嵌入到Y分量的DWT系数中，从而兼顾了水印的不可见性的鲁棒性，该算法既能在有源的条件下提取出嵌入的图像水印，也可以在无源的情况下，检测出水印的存在性，因此具有灵活性和应用范围广的特点，大量仿真结果证明了该算法的有效性。

A Watermarking Algorithm Based on DWT for Color Image

The work concerns with the watermarking algorithm that embed image data invisibly into a color image based on Discrete Wavelet Transform (DWT). The original color image is transformed into the YIQ color space. Exploiting the excellent properties of the wavelet transform and some characteristics of Human Visual System (HVS), encrypted watermark is embedded into the Y luminance component of the YIQ in DWT domain. Specifically, The algorithm can extract the embedded image watermark on the condition that original image can be attained and it also can detect the existence of the watermark even when the original image is absent. Thus it is characterized flexibility and wide utilization. The experimental results show that the watermarks are invisible and robust against noise and commonly used image-processing methods such as Guassian, Salt, Pepper noise, JPEG, crop procession etc.