Double-image sharing encryption based on associated fractional Fourier transform and gyrator transform

<正>We present a novel method for realizing double-image encryption algorithm by combining the images in different transform domains.Two original images are encrypted into two interim images by fractional Fourier transform and gyrator transform,respectively.The two encrypted images can be obtained by means of the addition and subtraction of the two interim images.This is defined as a double-image sharing scheme,in which the original images are encrypted into two parts.The original images cannot be recovered only with any one of the two interim images.Numerical simulation experiments demonstrate the validity of the algorithm.     

热压硫化锌后处理改性研究及其高温特性分析

硫化锌(ZnS)是一种重要的红外光学材料,在8～10 m波段范围内拥有较高的透过率,广泛应用于导弹整流罩、红外天文卫星、红外光谱仪、测量仪和热像仪等领域。采用高温后处理工艺方法可促进晶粒生长,并起到消除热压多晶ZnS内部的残余六方相和气孔的作用,进而可提升材料光学透过性能。对于厚度5 mm的热压ZnS试验片,1.064 m处透过率达到60%,2～10 m平均透过率达到73%。经后处理的光学窗口其抗冲击性能测试结果表明,材料保留了原有热压ZnS材料的力学特性,且在400 ℃的条件下能够满足光电探测系统清晰成像的要求。