Abstract: This paper presents an image scrambling algorithm based on Contourlet transform.In order to eliminate the negative effect of the entropy coding，it analyzes the structure and characteristic of Contourlet coefficients and proposes a fast image permutation method based on sub-tree.Efficient chaotic maps are used to produce permutation matrices.The cipher image satisfies requests for content masking.The simulation also implies it has good statistic characters.

摘要： 探讨了Contourlet变换域的图像视觉信息的置乱掩蔽问题，提出了一种基于零树编码结构的快速置乱算法。算法使用高效混沌映射构造置乱矩阵，对Contourlet系数矩阵进行子树间置乱，以减少系数置乱所带来的对编码效率的影响。实验结果表明该置乱算法效率高，并能有效实现对图像视觉内容的掩蔽。