【作者】 李勇军；

【导师】 杨青；

【作者基本信息】 西北农林科技大学 ， 机械设计及理论， 2007， 硕士

【摘要】 “精细农业”的核心是根据作物的实际需要,以最少的投入获得最佳的经济、生态效益,实现农业的可持续发展。信息采集是实施精细农业变量作业的重要组成部分,光谱测试以其简便、快速、精度高和无损检测等优点,成为当前国内外田间信息采集的研究热点。针对我国目前缺乏高精度、低成本田间作物氮营养诊断设备的现状,以及变量施肥的需要,本论文研究与开发了基于双光谱的叶绿素无损测试技术与系统。本文在比较、分析和借鉴现有国内外测量植被氮营养状况研究成果的基础上,利用光的吸收原理和光谱透射技术,设计了基于红光及近红外两特征波长处的叶绿素无损测试系统,实现了田间植被叶绿素相对含量的无损实时监测;基于实验方法,修正了归一化植被指数公式,建立了基于双光谱叶绿素无损测试系统的反演模型;为满足系统低功耗和可靠性设计要求,采用先进的集成芯片、模块化设计及光谱测试等技术,建立了系统的硬件平台;应用模块化设计思想、C语言及汇编语言的相互嵌套,设计了系统软件;采用了中位值平均滤波算法,降低了光电传感器转换中引入的非线性、以及干扰脉冲对测量的影响,有效地提高了系统测量精度。利用玉米叶片进行了系统标定和对比精度实验,结果表明:本系统与传统的80%丙酮浸提和分光光度法测得的叶绿素相对含量值比较吻合,和日本手持式叶绿素计Spad-502的测定结果相近;本论文提出的基于归一化植被指数修正公式的反演模型具有适用性。针对某些测量点吻合欠佳的情况,分析了数据差异的原因,提出了今后改进的措施。为进一步实现作物氮营养状况的实时无损监测,以及实施精细农业变量施肥技术提供了研究平台。更多还原

【Abstract】 The core of precision agriculture is to realize the sustainable development of agriculture by gaining the best economic and ecological benefits with the least input according to the actual needs of crops. Information acquisition occupies an important place in the variable status of a task in precision agriculture, and the spectrum technology has become the focal point of worldwide attention in the course of information collecting currently due to its simple, fast, precision and no-damage merits and so on.Aim at current situation of China is lack of low-cost and high-precision diagnosis equipment of nitrogen nourishment, as well as the variable fertilization needs, my thesis has researched and designed a none-damage chlorophyll measuring system based on two bands. By comparing, analyzing and adopting the scientific achievements of nitrogen nourishment worldwide, making use of sorption principle and spectrum transmission technology, a none-damage chlorophyll measuring system has been designed based on red light and near-infrared characteristics, and then successful to realize the none-damage real time monitoring of the chlorophyll content of crop vegetation. Basing on the experimental methods helped me correct the normalized vegetation index formula, and then the system inversion model has been established. In order to meet the low power loss and liability design request of the system, I adopted the advanced integrated chips, modularized design, spectrum testing and so on., then the system’s hardware platform were established. By applying the modular design thought, the nesting of the C and the assembly language, the system software has been designed. Middle value average filter formula has been proposed in order to reduce the influence caused by non-linearity and disturbance pulse when electro-optical sensor transforms were introduced, this also help to increase the system’s measuring accuracy effectively.Making use of the corn blade to have carried out system calibrating and the contrast accuracy experiment, which shows that result is close with measurement result by using Spad-502, is identical with traditional 80% acetone digestion and the relative magnitudes of chlorophyll spectrophotometry. The application of inversion model proposed has been tested based on the revised normalized vegetation index formula. Directing against some bad fitting points, the cause has been analyzed, and the improved measures have been brought forward. This study has provided the platform to the real-time none-damage monitoring of crops’nitrogen nutrition condition, as well as the implementation of variable fertilization in precision agriculture.更多还原