自适应分块的医学图像混沌加解密算法  

Digital medical image encryption and decryption algorithm based on chaotic mapping and adaptive partitioning

作　　者：拜亚萌[1] 张燕玲[1] 邓小鸿[2] Bai Yameng;Zhang Yanling;Deng Xiaohong(College of Information Engineering,Jiaozuo University,Jiaozuo Henan 454000,China;College of Applied Science,Jiangxi University of Science&Technology,Ganzhou Jiangxi 341000,China)

机构地区：[1]焦作大学信息工程学院,河南焦作454000 [2]江西理工大学应用科学学院,江西赣州341000

出　　处：《计算机应用研究》2020年第5期1478-1481,共4页Application Research of Computers

基　　金：国家自然科学基金资助项目(61762046);江西省自然科学基金资助项目(20161BAB212048)。

摘　　要：针对现有基于混沌的医学图像加密算法未考虑图像纹理特征的不足,提出了一种自适应分块的医学图像混沌加解密算法。首先利用2D Sine Logistic混沌系统生成两个具有良好混沌特性的安全序列;然后将图像分成固定尺寸的图像块,并计算图像块的最大像素差和方差,根据设定的阈值将图像块划分成纹理平滑块和纹理复杂块;最后利用混沌序列1对平滑块进行密文反馈加密,利用混沌序列2对复杂块进行明文反馈加密,得到加密后的图像。算法有效地考虑了图像块的纹理特性,优化了混沌加密算法,提高了医学图像的加解密效率。实验仿真结果表明,提出的算法具有高的安全性和加解密效率,相比现有方法加解密速度提高1倍左右。算法适用于大数据量的医学图像实时加解密。In order to solve the weakness of existing medial image encryption algorithm based on chaotic system in considering the image’s texture feature,this paper proposed a medical image encryption and decryption method based on chaotic mapping and adaptive partitioning.Firstly,it used the 2D Sine Logistic chaotic system to generate two secure sequences with good chaotic characteristics.Then,it divided the original medical image into fixed size image blocks,and calculated their maximum pixel difference and variance.According to the given threshold,it divided these image blocks into texture smooth blocks and texture complex blocks.Finally,it used the first chaotic sequence with ciphertext feedback mechanism to encrypt the smooth blocks,and encrypt the complex blocks by using the second chaotic sequence with plaintext feedback mechanism.Therefore,it obtained the encrypted image.Because the presented algorithm efficiently considered the texture characteristics of image blocks and optimized the algorithm of chaotic encryption,it improved the encryption and decryption efficiency of medical images.Experimental simulation results show that the presented algorithm has high security and encryption efficiency.Compared with the existent method,it reduces the encryption and decryption time by about 0.5 times.The presented algorithm is suitable for real-time medical images encryption and decryption with big data size.

关 键 词：医学图像 数据加密 混沌映射 纹理复杂度 自适应分块 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]