蜜瓜糖度透射光谱检测技术

Sugar Content Detecting of Muskmelons by Transmission Spectra

采用便携式USB光纤光谱仪建立了蜜瓜糖度透射光谱检测系统,光源能量300 W,光谱采集积分时间500 m s,离散光谱累计采集次数为4次,光谱平滑采用厢车法,平滑点数为4点。利用该系统对140个非网纹类蜜瓜糖度进行了检测试验,采用经典最小二乘法(CLS)、逐步多元线性回归(SMLR)、主成分回归分析(PCR)和偏最小二乘法(PLS)对样品光谱和糖度的建模与预测结果表明,PLS法的建模与预测结果较好,相关系数r为0.857,均方根校正误差为0.655,均方根预测误差为0.838。

A portable fiber spectrometer was employed for constructing a transmission spectra detecting system.The system took a 300W tungsten-halogen light source,the integration time for muskmelon samples was 500ms,cumulative integral times of discrete spectra was four,and the smooth method of spectra was boxcar method with four counts smoothing.The system was used to detect the sugar content for 140 samples.Based on the classical least square method（CLS）,stepwise multiple linear regress method（SMLR）,principal component regression method（PCR） and partial least square method（PLS）,four different models between the spectra and the sugar content were established.The test of models indicated that the PLS method was more appropriate for calibration and prediction,the correlation coefficient r was 0.857,root mean square errors of calibration was 0.655,and root mean square errors of prediction was 0.838.