彩色图像加密与压缩关联算法

Association Algorithm of Encryption and Compression for Color Image

针对传统的加密方法在彩色图像压缩方面的不足,提出一种用于保密通信的彩色图像加密与压缩关联算法。设计一个混合混沌系统在空域对秘密图像进行置乱。混沌系统产生针对彩色图像混淆变换的变换矩阵,改变载体图像的像素值。秘密图像每一像素的编码值与载体图像在设定区域中最佳像素点的坐标一一对应。最佳像素点按照最小欧氏距离的原则在载体图像的设定区域内搜索。经过压缩编码后的秘密图像数据不再是传统的像素值,而只是与序号或者下标对应的编码值。当压缩了67%的图像数据时,重构图像和原始图像的相似度仍然超过95%。对密钥空间、密钥的敏感性、加密图像的统计特性等加密效果进行仿真实验,结果表明,该算法安全性高、压缩率大,是一种有效的、易于实现的加密算法。

Aiming at the insufficiency of traditional encryption method in color image compression, a nassociation algorithm of color image encryption and compression is proposed for secure communication. A hybrid chaotic system is designed to scramble the secret image in time domain. Chaos system is also used to generate a transformation matrix for color images to confusion transform, which is used to change the carrier image pixels. Every pixel’s code value of secret image is one-to-one corresponded to the best pixel’s coordinates, which is searched in the carrier image’s setting area according to the principle of minimum Euclidean distance. After compression coding, the secret image data is no longer the traditional pixel value, but a group of code value corresponding the serial number or subscript. When 67 percent of the original image is compressed, the similarity between reconstructed image and original image is still more than 95%. The key space, sensitivity of the key and statistical features of encrypted image are also analyzed by simulation experiment. Simulation results show that the compression coding method has high security, large compression ratio, and is a kind of effective and easy to realize encryption algorithm.