基于整数小波变换的医学图像易碎水印方法

为了对医学图像进行快速鲁棒的认证提出了一种基于整数小波变换的易碎水印算法.该算法首先利用小波分解后的四叉树结构结合树节点上的统计信息和密钥来选择嵌入水印的位置,然后对确定嵌入水印的位置只嵌入1bit的水印信息.该算法具有以下特点：（1）图像嵌入水印后具有较高的信噪比,适用于医学图像的认证;（2）结合小波系数的统计信息来选择嵌入水印的位置,可保证水印的易碎性;（3）小波分解在空频域的特性使得算法对篡改有很强的定位能力;（4）可利用密钥对本算法进行保护,即使算法公开,也能抵挡恶意攻击.实验结果表明,该算法适用于医学图像的认证,并且复杂度较低,实用性较强.

A Fragile Watermarking Scheme for Medical Images Based on Integral Wavelet Transform

This paper presents a fragile watermarking scheme based on integral wavelet transform.The proposed method uses the Quadtrees structures received by the wavelet decomposition,statistical information on the nodes and secret key to choose the locations where to embed the watermarks.One bit watermark information will be embedded into the right location.The method has some characteristics:(1) it is adapts to medical images authentication due to the high Signal-to-Noise when the watermark embedded into images;(2) ensures the fragileness of watermark when it combines with the statistical information of wavelet coefficient to choose the locations where to embed the watermark;(3) it has a strong orientation ability for tampering because of the characteristics of wavelet decomposition in the spatial-frequency domain;(4) uses the secret key to protect the proposed method.It can resist the malice attack even if opening the method. The experimental result shows that the proposed method adapts to the medical images authentication,it is less complexity and more practicability.