一种基于直方图统计特征的灰度图像水印算法

A Watermarking Algorithm of Gray Image Based on Histogram Statistical Characteristics

直方图是数字图像的一个重要全局特征的表示方法,利用直方图的这个性质在空域里实施水印的嵌入和提出。在水印嵌入过程中,首先根据载体图像的特征得到其相应的直方图,即在相应灰度级下各个像素值出现的几率大小;然后计算出直方图相邻元素的距离,找出其最大值;再根据最大值和经过预处理过的二值水印来调整直方图的布局;最后得到含水印图像。在水印提取过程中,根据含水印图像和原始图像的直方图特点,找到嵌入水印的像素值,从而提取出水印。实验结果证明,该算法具有较好的抗几何攻击性质。

Digital image histogram is an important global features, histogram will be used to embed binary watermark in the space domain. In the watermark embedding process, firstly, the corresponding histogram of image is generated according to the original images＇ characteristics, which shows the probability Of the corresponding pixel in gray scale; Secondly, the distances between adjacent elements of histogram are calculated, and found their maximum; Then, the histogram is adjusted according to the maximum and pretreated watermark; Finally, the watermark image is generated. In the watermark extracting process, in accordance with the histogram of watermark image and the original image, and the pixels embedded watermark are found, thereby extracting watermark. The experimental results show that the algorithm has good anti - geometric nature of attacks.