Sormaz Miloš, Jenny Patrick
Laboratory for Media Technology, Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Dübendorf, Switzerland.
J Opt Soc Am A Opt Image Sci Vis. 2012 Oct 1;29(10):2174-80. doi: 10.1364/JOSAA.29.002174.
Monte Carlo simulations were performed in order to obtain reflectance measurements from phantoms typically used in biomedical optics when either unpolarized or circularly polarized incident light is used. Phantoms contain spherical targets of different diameters, placed at different depths, with higher absorption than the surrounding medium, which are detected using a coaxial setup of laser and detector. The considered turbid media have highly anisotropic scattering phase functions, so detected light for the considered times of flight is not diffuse, but rather in the multiple-scattering regime. Therefore, the target reconstruction methods typically used in diffuse optical imaging cannot be employed. However, spatially resolved reflectance measurements in the time domain allow use of a novel reconstruction method based on the approximation of average photon trajectories, which are functions of the separation distance from the point of incidence and of the time of flight. With the approximated average photon trajectories, one can estimate the depth of the target.
进行了蒙特卡罗模拟，以便在使用非偏振或圆偏振入射光时，从生物医学光学中常用的体模获得反射率测量值。体模包含不同直径的球形目标，放置在不同深度，其吸收率高于周围介质，使用激光和探测器的同轴设置进行检测。所考虑的浑浊介质具有高度各向异性的散射相位函数，因此在所考虑的飞行时间内检测到的光不是漫射的，而是处于多重散射状态。因此，通常用于漫射光学成像的目标重建方法不能采用。然而，时域中的空间分辨反射率测量允许使用一种基于平均光子轨迹近似的新型重建方法，平均光子轨迹是与入射点的分离距离和飞行时间的函数。利用近似的平均光子轨迹，可以估计目标的深度。
