基于位置交换的快速图像置乱

Fast image scrambling based on position interchange

为了提高图像置乱算法的置乱效率,提出了一种基于帐篷映射的快速随机排列算法,并把这种方法应用到图像置乱领域,构建了基于混沌序列的快速图像置乱算法。该快速随机排列以位置交换为核心,通过应用概率的几何意义,把由帐篷映射产生的服从非均匀分布的混沌序列转化为服从均匀分布的随机序列,驱动图像元素位置交换完成随机排列。理论和实验结果表明:快速随机排列在效率上优于基于排序算法的随机排列,构建的快速图像置乱算法与传统基于混沌排序图像置乱算法相比,密钥空间更大,运行效率更高。

In order to efficiently scramble image, based on skew tent map, a fast random permutation procedure was firstly presented, and then a fast image scrambling algorithm, based on the preceding procedure, was designed. The main idea behind the fast random permutation was position interchange. Its implementation process was, based on geometrical meaning of probability, non-uniform distribution chaos sequence generated by skew tent map was transformed into uniform random sequence, which then drove image element to interchange position. Theory and experiments results demonstrate that the fast random permutation has better efficiency then sorting-based random permutation, the proposed image scrambling method has larger key space and higher running efficiency than sorting-based image scrambling.