湿度对近红外光谱检测的影响

光谱的检测过程会受诸如温度等很多条件的影响。本课题的目的在于研究在近红外检测过程中，环境湿度的变化对苹果检测结果的影响。建立一个自制湿度可控箱，通过改变箱内小环境的湿度值，对每个水果在40%～80%的湿度范围内每隔10%进行光谱采集。每个最终光谱是由水果的扫描光谱减去背景光谱获得的，由于不确定湿度随水果和背景的分别影响，光谱试验分两组进行：在不同的湿度下均采集背景和水果的光谱值(组1)和仅在40%的湿度值下采集背景(组2)。由20个苹果的样品集组成40组平行试验数据，运用单因素方差分析和马氏距离等处理方法进行分析。结果显示，无论在不同的湿度值下采集光谱和背景还是仅采集一个背景，其湿度值对近红外光谱的影响都不显著。

Effect of Humidity on Detection of Near-Infrared Spectra

Spectral performance would be affected by many factors such as temperature, equipment parameters and so on. Humidity fluctuations may occur in practice because of varying weather conditions. The objective of the present research was to find out whether the change in humidity would influence the near infrared spectrum. In this trial, an airproof, humidity-controllable test-bed was established to change the humidity of the mini environment. At 40%, 50%, 60%, 70% and 80% degrees of humidity, each sample's final spectrum was obtained by removing the background's spectrum from the sample's. As whether the influences of the sample's spectrum and the background's are equal wasn't known, this trial was divided into two groups: detecting background and sample at each degree of humidity (group 1) and background's detecting just performed at 40% degree of humidity (group 2). This research was based on the hardware of NEXUS intelligent FTIR spectrometer, made by Nicolet instrument company U. S. A, using fiber optic diffuse reflectance accessory. The final spectrum was analysed using single variance analysis and Mahalanobis distance methods. The result shows that neither in group 1 nor in group 2, humidity had little influence on NIR.