Yale University, Department of Computer Science, Computer Graphics Group, New Haven 06511, United States.
University of British Columbia and Vancouver Coastal Health Research Institute, Department of Dermatology and Skin Science, Photomedicine Institute, Vancouver V5Z 4E8, Canada.
J Biomed Opt. 2016 Jul 1;21(7):71117. doi: 10.1117/1.JBO.21.7.071117.
In the framework of further development of a unified computational tool for the needs of biomedical optics, we introduce an electric field Monte Carlo (MC) model for simulation of backscattering of coherent linearly polarized light from a turbid tissue-like scattering medium with a rough surface. We consider the laser speckle patterns formation and the role of surface roughness in the depolarization of linearly polarized light backscattered from the medium. The mutual phase shifts due to the photons’ pathlength difference within the medium and due to reflection/refraction on the rough surface of the medium are taken into account. The validation of the model includes the creation of the phantoms of various roughness and optical properties, measurements of co- and cross-polarized components of the backscattered/reflected light, its analysis and extensive computer modeling accelerated by parallel computing on the NVIDIA graphics processing units using compute unified device architecture (CUDA). The analysis of the spatial intensity distribution is based on second-order statistics that shows a strong correlation with the surface roughness, both with the results of modeling and experiment. The results of modeling show a good agreement with the results of experimental measurements on phantoms mimicking human skin. The developed MC approach can be used for the direct simulation of light scattered by the turbid scattering medium with various roughness of the surface.
在进一步开发用于生物医学光学需求的统一计算工具的框架内，我们引入了一个用于模拟相干线偏振光从具有粗糙表面的类组织散射介质后向散射的电场蒙特卡罗（MC）模型。我们考虑了激光散斑图案的形成以及表面粗糙度在介质后向散射线偏振光退偏振中的作用。考虑了由于介质内光子路径差以及介质粗糙表面上的反射/折射引起的相互相位移动。模型验证包括创建各种粗糙度和光学特性的幻影、测量背散射/反射光的同偏振和交叉偏振分量、对其进行分析以及使用 NVIDIA 图形处理单元上的计算统一设备架构 (CUDA) 进行并行计算加速的广泛计算机建模。空间强度分布的分析基于二阶统计量，该统计量与表面粗糙度具有很强的相关性，与建模和实验结果均具有相关性。建模结果与模拟人体皮肤的幻影的实验测量结果吻合良好。所开发的 MC 方法可用于直接模拟具有各种表面粗糙度的混浊散射介质散射的光。
