非均匀混浊介质多光谱反射成像的仿真与实验研究

提出了一种采集高动态范围多光谱反射率的实验方 法,并通过测量5个非均匀混浊介 质样品在全视场照射条件下和500~940nm波长范围内的反射图像数据 证明了本方法的可行性。同时 采用在辐射传输理论框架下建立的并行iMC蒙特卡罗仿真模型,通过使用漫反射标准板准确 记录入射光 束能量分布,输入至iMC仿真程序,获得可与反射率测量数据相比较的反射率仿真图像数据 。本文工 作为求解根据反射率确定非均匀混浊介质样品的光学特征与几何参数的逆问题提供了实验与 理论工具。

Simulation and experimental studies of heterogeneous turbid medium by multispect ral reflectance imaging

Development of quantitative and non-i nvasive methods for determination of optical parameters of turbid media can have wide applications in material analysis and medicine.We present a novel method t o acquire multispectral and high dynamic range reflectance images that can be compared wit h simulated image data to investigate the dependence of the image contrast on the optical properties of heterogeneous turbid samples.At each wavelength, the distribution of reflected light intensity at the surface of a turbid phantom is acquired from a camera with 4different exposure times which are used to determine a high dynamic range refl ection image.The incident beam profile is measured with a diffuse reflectance standard to obtain a reflectance image at each wavelength.The image of the incident beam profile is also imported into a Monte Carlo model to accura tely obtai n the simulated reflectance images within the framework of radiative transfer theory.We have measured refle ctance images of 5heterogeneous turbid samples in the spectral range from 500nm to 940nm.By accurate measurem ent of reflectance image with a full-field illumination using a diffuse reflectance standard and image simulati on with the Monte Carlo method,we demonstrate the feasibility to obtain the optical parameters of the turbid samp les with the measurement and simulation methods in a wide spectral region from 500nm and 940nm.