Virtual-source diffusion approximation for enhanced near-field modeling of photon-migration in low-albedo medium.
Virtual-source diffusion approximation for enhanced near-field modeling of photon-migration in low-albedo medium.
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DOI：
10.1364/oe.23.001337
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发表时间：
2015-01
期刊：
影响因子：
3.8
通讯作者：
M. Jia;Xueying Chen;Huijuan Zhao;Shan-shan Cui;M. Liu;Lingling Liu;F. Gao
中科院分区：
文献类型：
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作者：
M. Jia;Xueying Chen;Huijuan Zhao;Shan-shan Cui;M. Liu;Lingling Liu;F. Gao
大多数描述光在混浊介质中传播的分析方法在准直光源的近场中显示出低的有效性。受电磁场理论中的电荷模拟方法和已建立的基于离散源的模型的启发，本文提出了一种改进的半无限几何显式模型，称为“虚拟源”(VS)扩散近似(DA)，以适应低反照率、中等和短源-探测器分离。在该模型中，标准DA中的准直光被类比地近似为沿入射方向分布的多个各向同性点源。为了提高性能，在近场中采用了计算反射率与真实反射率之间的拟合过程来优化VS参数(强度和位置)。为了便于实际应用，基于对典型光学参数范围内的VS参数的闭合推导，建立了显式的2VS-DA模型。这种参数化方案继承了DA近似的数学简单性，同时大大扩展了它在模拟低反照率介质中近场光子迁移的有效性。通过与蒙特卡罗模拟结果的比较，证明了提出的VS-DA方法在较宽的源-探测器分离范围和介质光学性质上的优越性。
Most analytical methods for describing light propagation in turbid medium exhibit low effectiveness in the near-field of a collimated source. Motivated by the Charge Simulation Method in electromagnetic theory as well as the established discrete source based modeling, we herein report on an improved explicit model for a semi-infinite geometry, referred to as "Virtual Source" (VS) diffuse approximation (DA), to fit for low-albedo medium and short source-detector separation. In this model, the collimated light in the standard DA is analogously approximated as multiple isotropic point sources (VS) distributed along the incident direction. For performance enhancement, a fitting procedure between the calculated and realistic reflectances is adopted in the near-field to optimize the VS parameters (intensities and locations). To be practically applicable, an explicit 2VS-DA model is established based on close-form derivations of the VS parameters for the typical ranges of the optical parameters. This parameterized scheme is proved to inherit the mathematical simplicity of the DA approximation while considerably extending its validity in modeling the near-field photon migration in low-albedo medium. The superiority of the proposed VS-DA method to the established ones is demonstrated in comparison with Monte-Carlo simulations over wide ranges of the source-detector separation and the medium optical properties.