本文提出了基于近红外光谱的茶叶成份检测仪的设计与实现。该检测仪采用干涉滤光片作为分光器件,其旋转样品池内嵌了漫反射标准白板,以实现快速交替检测样品及白板漫反射信号,使样品与白板的检测同步完成,简化仪器机械结构, 提高了光谱稳定性和样品检测速度与精度。光电信号检测系统采用了InGaAs 光电探测器,利用仪表放大器和24 位A/D 转换器分别完成信号调理和数据采集,以USB 2.0 实现仪器与计算机的数据传输,再由计算机化学计量学软件完成吸光度计算及茶叶样品的成分分析。实验结果表明,本样机实测茶叶成份值与理化检验值的相对误差小于5%。

Design and realization of tea component analyzer is presented based on Near-infrared (NIR) spectrometry. The discrete interference filters are used as NIR diffuse reflectance part. A white board is embedded into the rotatable sample cell. The samples and the white board are scanned in a fast and alternative way, which tests sample and the white board simultaneously, effectively simplifying the mechanism and accelerating the sample detection as well as improving the accuracy. InGaAs Detector, instrumental amplifiers and 24-bit A/D converters are used in photoelectric signal processing system. The computer completes the value determination of absorbency and tea component analysis with the data transferred from USB 2.0 interface. The relative error between this instrument and conventional chemical analysis is less than 5% by the experiments result.