混浊介质中的目标识别及其在交通安全中的应用

结合迷雾天气中车辆交通安全研究的核心内容——目标识别问题,利用斯托克斯/米勒表述和蒙特卡罗方法探讨偏振光在大气这类混浊介质中的传输规律,利用反射米勒矩阵对混浊介质中隐藏的目标物体进行识别。数值计算结果表明,在一定距离之内,利用反射米勒矩阵计算的解偏度能够较好地分辨出混浊介质中隐藏的不同物体。结合迷雾天气的具体特点,分析有效识别距离的大小,定量说明了识别距离大于能见距离,高于直接利用人眼识别的水平。     

Discriminating optical parameters in double-layer turbid media by backscattered polarization patterns

In this letter a Monte Carlo(MC) algorithm is used to simulate the propagation of polarized light in double-layer turbid media and the 2-dimentional backscattered Stokes vectors and Mueller matrices are obtained.Relationships between backscattered Mueller matrix and optical properties,such as scattering,absorption and layered structure,are discussed in detail.Integrating the 2-dimentional Mueller matrix elements along radial and azimuthal directions,we obtain a reverse trend with respect to the optical parameters for upper and lower layers,which suggests possibilities for discriminating subtle optical properties in a double-layer structure using backscattered polarization patterns such as Mueller matrix.     

鲜红斑痣数值计算模型的构建及其蒙特卡罗模拟

基于人体皮肤的组织结构以及鲜红斑痣(PWS)皮肤的病理特征,光在皮肤组织中的传输特性以及皮肤各层的组织光学参数,建立了一种具有多层组织结构的鲜红斑痣皮肤数值模拟计算模型,介绍了该模型中组织光学参数的确定方法.利用蒙特卡罗(MC)方法结合临床数据对模型进行了验汪,同时计算了光能量在PWS皮肤中随深度的分布,结果可为临床上如何选择最佳光剂量提供部分参考依据.利用本模型做进一步的详细完整的计算可以为光动力学治疗PWS提供理论支持.     

手性介质中后向散射米勒矩阵特性及其在血糖无创检测中的应用初探

利用斯托克斯-米勒矩阵表述分析偏振光在手性介质中的传输规律,利用瑞利近似下的单次散射模型和基于米氏散射理论的多次散射的蒙特卡罗方法,探讨葡萄糖对后向散射偏振光传输特性的影响,计算了不同葡萄糖浓度下的后向散射米勒矩阵. 结果表明在含有葡萄糖的手性介质中后向散射米勒矩阵的若干矩阵元表现出微弱的旋光效应,旋光度随葡萄糖浓度增大而增大. 为了检测低浓度下微小的旋光变化,定义了函数对含-不含葡萄糖的米勒矩阵元图像进行处理,提取由葡萄糖引入的图像差异. 结合无创血糖检测应用要求,分析了葡萄糖生理浓度下的矩阵元图像,获 关键词： 医用光学与生物技术 偏振光 斯托克斯-米勒表述 蒙特卡罗模拟     

基于蒙特卡罗模拟的散射介质中后向光散射模型及分析应用

构建了内光源模型探讨散射介质中的光散射现象,利用蒙特卡罗方法研究了逃逸出组织的后向散射光子数随光子在组织内部发生的散射次数的分布关系,探讨了光源照明方式、辐射强度、接收方式、调制等参数的变化对后向散射的影响,结果表明后向散射光子的数量随散射次数的分布并非简单的单调递增或递减,而是一条先增大后减小出现峰值的曲线. 峰值位置、峰值大小及曲线形状与光源、探测方式、组织光学特性参数等有关. 关键词： 医用光学与生物技术 散射介质 后向散射 蒙特卡罗模拟     

Influence of single scattering and multiple scattering on backscattered Mueller matrix in turbid media

Monte Carlo algorithm and Stokes-Mueller formalism are used to simulate the propagation behavior of polarized light in turbid media. The influence of single scattering and multiple scattering on backscattered Mueller matrix in turbid media is discussed. Single and double scattering photons form the major part of backscattered polarization patterns, while multiple scattering photons present more likely as background. Further quantitative analyses show that single scattering approximation and double scattering approximation are quite accurate when discussing the polarization patterns near the incident point.     

Theoretical analysis of backscattered polarization patterns of turbid media containing glucose

Single scattering model and Stokes-Mueller formalism are introduced to investigate the influence of glucose on backscattered polarization patterns in turbid media. Glucose molecules rotate the polarization plane and induce changes in backscattered Mueller matrix patterns. Some Mueller matrix elements present higher optical rotation as the concentration of glucose augments. Using image subtraction and integration, linear relationship between low glucose concentration in the physiological range and optical rotation degree can be derived.