基于光调制技术的混浊介质空间散射光信号检测方法研究

Study on the Measurement Method of Spatially Scattered Light Signals of Turbid Media Based on Optical Modulaiton

为提高被测混浊介质样品漫反射、漫透射和准直透射光信号的测量信噪比,首次将光调制技术运用于空间多点特征光信号的检测中。测量系统以调制盘转动频率对样品入射光强进行频率调制,然后对采集的多点光强数据通过离散傅里叶变换进行解调,提取调制频率点的谐波分量作为测量值。用该方法对浓度为8%,直径为0.7μm的聚苯乙烯小球悬浮液进行了实验测试,结果表明该方法能有效提高被测样品特征光信号的测量信噪比,为强噪声背景下混浊介质光学参数研究提供了新的途径和方法。

To improve the signal-to-noise ratio of diffuse reflectance, diffuse transmittance and collimated transmittance sig- nals, optical modulation is adopted to detect the spatially scattered light of the measured turbid media for the first time. First, the incidence light is modulated by the rotating frequency of turnplate. Second, inspect the spatially scattered light on multi spots around the measured sample, and demodulate the collected datas by DFT; Third, extract the maximum harmonic components as the measured results of spatially scattered light on multi spots. The described method is applied to determine the optical parameters of 0. 7 btm, 8~/oo polystyrene mierospheres solution sample and the accuracy of the inverse solution has been examined. The experimental results show that the optical modulation can improve the signal-to-noise ratio of the spa- tially scattered light signals of the measured turbid media. This method can provide a new rapid and accurate approach for optical study and material analysis of turbid medium samples.