在這篇研究中我們建構了一種嶄新的光子演算模型，其利用波長500到1000奈米的漫反射光譜，除了可精確算出潛層組織的吸收係數與散射係數以外，更可進一步反算出另一與組織粒子型態相關的相位函數。量測淺層組織需要使用很短的光源與偵測器距離，但一般漫反射光譜傳播演算法在此狀況下會因為光子在沒有經過足夠的散射便回到偵測器，而使原本只考慮第一階粒子散射角度期望值的Henyey-Greestein相位函數不再符合短距離偵測端下的散射現象。為了全面的描述在短距離偵測端下的粒子散射行為，我們使用運算較複雜的米氏理論去取代原本的相位函數，結合利用圖形處理器多核心架構的蒙地卡羅演算法，進而模擬單色光打到粒子的散射情形並建構不同吸收散射的光譜值資料庫。而這邊我們加入了第三個有助於描述相位函數的光學參數，此光學參數包含了第一階與第二階的散射角度期望值，因此可以更詳細的描述短偵測端距離下的散射狀況。此資料庫配合類神經網路與最小平方法創造出一個全新的模型，其可以反算樣本的吸收散射係數與相位函數。經由比較舊有的相位函數與米氏相位函數所建構成的演算法去反算模擬皮膚的均質液態假體，我們證明此演算法的可用性，且米氏理論的加入的確可以較舊有相位函數更精確的算出假體的吸收、散射係數與相位函數。而最後本研究也量測了不同部位活體皮膚的光學參數，進而去了解淺層皮膚的光學性質與粒子分布的可能性。

In this thesis we build a novel photon calculated algorithm, by using the diffuse reflectance spectroscopy(DRS) from 500 to 1000 nm wavelength, this model not only can determine the absorption coefficient (μ_a) and reduced scattering coefficient (μ_s') of tissues, but also can recover another which is a scattering particle type related parameter called phase function γ. The DRS measurement of superficial tissue need shorter source-detector separation, however the typical photon transport model, where the Henyey-Greenstein phase function only consider the first order expected value of the scattering angle distribution, in this condition may no longer suitable for describing the photon scattering phenomenon cause the photon do not undergo enough scattering before back to the detector. To completely describe the particle scattering behavior in shorter source-detector separation, we use a more rigorous Mie theory to replace the ordinary phase function. The new phase function was combined into the parallel computed Monte Carlo method implemented by the graphics processing units to simulate the scattering condition of a monochromatic light hit a specific particle, and to further constructed the reflectance database of different optical properties. Here we added the consideration of the third parameter γ which contained the first and second order of scattering angle expected value to depict the phase function of scattering more comprehensively. We further utilized the reflectance database to establish a connection between the optical properties and diffuse reflectance spectra with Artificial Neural Network and least-squares method. By comparing the calculated result of biomimetic liquid phantoms with algorithm made by original Henyey-Greenstein phase function and Mie phase function, we verified the usability of this new algorithm which employed Mie theory as the phase function, and it indeed can recover μ_a, μ_s' γ of sample more accurately. Finally, we also measured different positions of human arm skin to reveal the properties and scattering particle distribution of shallower skin tissue.

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