基于LED的便携式土壤有机质检测仪的研制

发布时间：2018-05-06 08:54

本文选题：土壤有机质 + 二维相关光谱　；参考：《山西农业大学》2015年硕士论文

【摘要】：土壤有机质是土壤养分的重要组成成分,它的含量与土壤肥力有密切关系。传统的土壤有机质测量方法普遍存在测量周期长、成本高、工作繁琐等问题,因此开发一款基于光谱原理的便携式土壤有机质检测仪,有着重要意义。本文主要开展如下工作：(1)简要阐述了土壤有机质的基本性质及常见测量方法,分析了光谱法测量土壤有机质的基本原理,介绍了国内外土壤有机质测定仪研究的进展。(2)将采集的土样进行过筛、烘干、标号等处理后,选取6个典型样本,利用美国ASD (Analytical Spectral Device)公司的FieldSpec3光谱仪进行测定,得到它们的光谱图。对原始数据进行预处理,并比较6个样本的光谱曲线,得出土壤有机质含量越高,吸光度值也越大,同时分析其一维光谱图,得出450-680nm是土壤有机质的敏感波段。(3)利用二维相关光谱技术,可以将光谱信号扩展到二维,从而得到原始谱图数据中难以发现的信息。对实验数据进行二维相关分析后,得到了更精确的土壤有机质敏感波段,在可见光区域600nnm左右土壤有机质与吸光度的相关性最高,为下一步便携式土壤有机质快速测定仪的开发提供了理论基础。(4)开发第一代基于LED光源的便携式土壤有机质检测仪。以低功耗、便携、效率高为基本原则,设计了仪器总体系统结构。选用体积小、亮度高、寿命长、成本低的LED作为光源,采用灵敏度高、暗电压低的TSL253作为光信号探测器,以Y型光纤进行光的传导。仪器包含光路和电路两部分,LED光源、特制光纤、光电探测器组成了系统光路部分,放大电路、A/D转换、1602液晶显示组成系统电路部分。(5)在特制的暗室中对仪器进行了实验验证。对仪器进行重复性实验,其误差仅为1.13%,满足了一般仪器的要求。用自主开发的仪器测量了10个土壤样本的有机质含量。对所测得数据与土壤实际值数据进行分析,建立了一元线性模型,预测了另外5个土样的有机质含量,系统的平均误差为6.64%,符合便携式仪器的误差要求。
[Abstract]:Soil organic matter is an important component of soil nutrients, and its content is closely related to soil fertility. Traditional methods of soil organic matter measurement have many problems, such as long measuring period, high cost and tedious work. Therefore, it is of great significance to develop a portable soil organic matter detector based on spectral principle. The main work of this paper is as follows: (1) the basic properties and common measuring methods of soil organic matter are briefly described, and the basic principle of measuring soil organic matter by spectral method is analyzed. This paper introduces the development of soil organic matter analyzer at home and abroad. (2) after sifting, drying, labeling and so on, 6 typical samples are selected and determined by FieldSpec3 spectrometer of ASD Analytical Spectral device Company. Get their spectra. By preprocessing the original data and comparing the spectral curves of 6 samples, it is concluded that the higher the content of soil organic matter, the greater the absorbance value, and at the same time, the one-dimensional spectral map is analyzed. It is concluded that 450-680nm is the sensitive band of soil organic matter. (3) by using two-dimensional correlation spectroscopy, the spectral signal can be extended to 2-D, and the information which is difficult to find in the original spectral data can be obtained. Based on the two-dimensional correlation analysis of the experimental data, a more accurate sensitive band of soil organic matter was obtained, and the correlation between soil organic matter and absorbance was the highest in the visible light region, and the correlation between soil organic matter and absorbance was the highest in the visible region. The first generation of portable soil organic matter detector based on LED light source was developed. Based on the principle of low power consumption, portable and high efficiency, the overall system structure of the instrument is designed. LED with small volume, high brightness, long life and low cost is used as light source, TSL253 with high sensitivity and low dark voltage is used as light signal detector, and Y type optical fiber is used to conduct light. The instrument consists of two parts: light circuit and circuit, special optical fiber and photodetector constitute the optical circuit of the system, and the amplifier circuit / A / D converter / 1602 liquid crystal display is composed of the system circuit part. 5) the instrument is experimentally verified in a special darkroom. The repeatability experiment shows that the error is only 1.13, which meets the requirements of general instruments. The content of organic matter in 10 soil samples was measured by a self-developed instrument. Based on the analysis of the measured data and the actual soil value data, a single linear model is established, and the organic matter content of the other five soil samples is predicted. The average error of the system is 6.64, which accords with the error requirement of portable instruments.
【学位授予单位】：山西农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP216;S153.621

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