基于Gabor滤波器组与DWT的遥感影像感知哈希认证算法

A Perceptual Hash Algorithm Based on Gabor Filter Bank and DWT for Remote Sensing Image Authentication

针对遥感影像的数据特点,提出一种基于Gabor滤波器组与DWT的遥感影像感知哈希认证算法。该算法利用Gabor滤波器能够在不同方向和频率增强图像的特点,基于自适应策略在不同尺度下提取遥感影像不同区域的边缘特征生成感知哈希序列,对信息丰富的影像区域进行更严格的完整性认证。首先,对遥感影像进行格网划分,根据格网单元的信息熵"自适应"地确定Gabor滤波器组的参数;然后,通过多方向Gabor滤波器对各格网单元进行滤波变换;继而采用DWT变换与PCA分解提取与处理格网单元的边缘特征,最终生成影像的感知哈希序列。影像的认证过程,通过比较待认证影像与原始影像的感知哈希序列之间的归一化Hamming距离实现。实验与分析表明,该算法能够有效检测遥感影像局部细微篡改,同时能够对保持内容不变的影像操作具有鲁棒性,且具有较高的运行效率,实现了高效的遥感影像的内容完整性认证。

In the light of the data characteristics of the remote sensing image,aperceptual hash algorithm based on Gabor filter bank and DWT for remote sensing image authentication was proposed.Using the characteristics of Gabor filter in image enhancement in different directions and frequencies,the algorithm,based on'adaptive strategy',generated perceptual hash sequence by extracting the edge features of remote sensing image in different areas and under different scales,to conduct more stringent integrity authentication of the information intensive image region.Firstly the remote sensing image was divided into grids to determine the parameters of Gabor filter bank according to the entropy of the grid.Then,the filtering transformation was conducted on the grids through multi-directional Gabor filter.Thirdly,the local edge feature of the grid was extracted and compressed by DWT and PCA to generate the perceptual hash value.The authentication procedure was achieved via the normalized Hamming distance between the hash values generated from the remote sensing image to be authenticated and the original hash value.The experiment results showed that the algorithm can effectively detect the local minor tamper of the remote sensing image while being robust to content-preserving operations.With a higher running efficiency,an efficient content integrity authentication for remote sensing images was achieved.