A method is proposed for optical characterisation of materials, which is a very important input for realistic channel simulation based on Monte-Carlo Ray-Tracing algorithms. This original approach consists first of all in carrying out some measurements of the optical power received after propagation in the environment containing the materials sought, using a simple and low-cost experimental setup. In a second step, this approach is based on an optimization algorithm. It takes as input the optical power measurements made, associated with the parameters of the measurement environment, such as the positions or properties of the sensors. This algorithm searches for the parameters of the material reflection models, minimising the difference between the optical measurement and the simulation. Two cost functions are studied to perform this search and showed that the correlation measure is the more robust one. To avoid uncertainties in the real input data, this approach is discussed using only a virtual configuration with well-controlled input data and thus a virtual measurement obtained by simulation. The results show that this method produces a correct estimate of the Bidirectional Reflectance Distribution Function (BRDF) albedos, provided that the chosen BRDF models correspond well to the reflection behaviour of the materials, and that the materials have a significant influence on the measured optical power.

中文翻译：

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结合测量和蒙特卡罗模拟的光学无线通信材料表征

提出了一种用于材料光学表征的方法，这是基于蒙特卡罗光线追踪算法的实际通道模拟的非常重要的输入。这种原始方法首先包括使用简单且低成本的实验装置，对在包含所需材料的环境中传播后接收到的光功率进行一些测量。第二步，该方法基于优化算法。它将进行的光功率测量作为输入，与测量环境的参数（例如传感器的位置或属性）相关联。该算法搜索材料反射模型的参数，最大限度地减少光学测量和模拟之间的差异。研究了两个成本函数来执行此搜索，并表明相关性度量更为稳健。为了避免实际输入数据的不确定性，仅使用具有良好控制的输入数据的虚拟配置以及因此通过仿真获得的虚拟测量来讨论该方法。结果表明，该方法可以正确估计双向反射分布函数 (BRDF) 反照率，前提是所选的 BRDF 模型与材料的反射行为很好地对应，并且材料对测量的光功率有显着影响。仅使用具有良好控制的输入数据的虚拟配置以及通过模拟获得的虚拟测量来讨论该方法。结果表明，该方法可以正确估计双向反射分布函数 (BRDF) 反照率，前提是所选的 BRDF 模型与材料的反射行为很好地对应，并且材料对测量的光功率有显着影响。仅使用具有良好控制的输入数据的虚拟配置以及通过模拟获得的虚拟测量来讨论该方法。结果表明，该方法可以正确估计双向反射分布函数 (BRDF) 反照率，前提是所选的 BRDF 模型与材料的反射行为很好地对应，并且材料对测量的光功率有显着影响。