基于主动光源的作物生长信息监测仪的设计与实现

发布时间：2018-08-24 19:59

【摘要】：作物生产精确管理是基于信息技术和数据知识的一种现代农业栽培技术,其结合了农作物信息的采集、数据处理和管理调控等技术措施,能够最大限度的利用生产资源,实现农业生产的高效、高产和低污染,对现代农业的发展具有重大的推动作用。农作物信息的采集是作物生产精确管理实现的基础,如何实现农作物信息快速、准确的获取,是当今精确农业所亟需解决的关键问题。本论文针对田间作物生长信息获取的迫切需求,研制了一种基于主动光源的作物生长信息监测仪。首先,论文阐明了我国传统农业所面临的问题及精确农业发展的重要性,并分析作物生长信息的获取对于实现作物生产精确管理的重要作用,综合叙述了近年来国内外关于作物生长信息光谱监测设备研发的进展以及存在的问题,提出了本研究的研究目的与意义,并规划与确定了研究内容和技术路线。根据本研究的内容分析了基于光谱无损监测的特点和优越性,简述了作物近红外光谱无损监测的响应机理、作物冠层反射光谱特性的描述方法和所监测的光谱植被指数的定义,设计了基于主动光源的作物生长信息监测仪的总体实现方案。其次,本文根据作物冠层行播分布特性和稻麦作物敏感波段730nm、810nm获取需要,设计了用于获取作物冠层730nm、810nm反射光谱的作物冠层反射光谱传感器。该传感器主要包括由光源驱动电路与光源光路单元组成的光源系统、光谱信号采集光路单元与微弱信号调理电路组成的光谱信号采集系统以及双激光精确测距系统。其中光源系统采用LED恒流调制和滤光片滤光结合的方式,防止外界光信号对测试结果的影响,光源调制频率为1KHz,滤光片中心波长为730nm和810nm,带宽均为10nm。其中光源驱动电路由方波信号发生器、电平转换电路、恒流驱动电路组成;微弱信号调理电路由前级I-V放大电路、无源带通滤波器电路、后级同向放大电路、信号检波电路组成。作物冠层反射光谱传感器光源系统发出光强恒定的730nm、810nm调制光谱信号照射作物冠层,光谱信号采集系统接收作物冠层反射的调制光谱信号,实现作物冠层反射光谱强度的获取。其中光源光路单元实现LED光源光线的准直与聚光,光谱信号采集光路单元实现作物冠层反射光谱的聚光和滤波功能。再次,本文依据作物冠层反射光谱传感器输出信号和田间测试需要,采用内部集成ADC模块的ATmega32作为核心控制芯片,配合温湿度传感器、键盘输入、液晶显示、声光提醒、SD卡存储和电源管理等组成的控制部分硬件电路;采用C语言设计嵌入式控制软件,实现作物生长信息的采集、显示和存储,利用SolidWorks设计了监测仪的结构图,并根据结构图对监测仪进行机械加工。最后,本文为了检验监测仪的测试性能,分别对监测仪进行了功能试验和田间试验。功能试验包括稳定性测试、抗光照干扰测试、回程误差测试、标定试验、温度性能测试等试验;田间试验包括反射率验证、作物生长信息验证、叶面积指数验证等试验。通过功能试验和田间试验结果表明所设计的作物生长信息监测仪的性能良好,能够满足大田作物生长信息的快速、准确获取的需要。
[Abstract]:Precise management of crop production is a kind of modern agricultural cultivation technology based on information technology and data knowledge. It combines the technical measures of crop information collection, data processing and management control. It can maximize the use of production resources and achieve high efficiency, high yield and low pollution of agricultural production. It is of great significance to the development of modern agriculture. Acquisition of crop information is the basis of accurate management of crop production. How to obtain crop information quickly and accurately is the key problem to be solved urgently in precision agriculture nowadays. Firstly, the paper clarifies the problems faced by traditional agriculture and the importance of precision agriculture development in China, and analyzes the important role of crop growth information acquisition in the realization of accurate management of crop production. The development and existence of spectral monitoring equipment for crop growth information at home and abroad in recent years are summarized. According to the contents of this study, the characteristics and advantages of non-destructive monitoring based on spectroscopy are analyzed, and the response mechanism of near-infrared spectroscopy for non-destructive monitoring of crops, the description method of reflectance spectroscopy characteristics of crop canopy and the monitored light are briefly described. Secondly, according to the characteristics of crop canopy row-seeding distribution and the needs of acquiring sensitive bands 730 nm and 810 nm of rice and wheat, a crop canopy reflectance spectrum sensor was designed to obtain the reflectance spectrum of 730 nm and 810 nm of crop canopy. The sensor mainly consists of a light source system consisting of a light source driving circuit and a light source light path unit, a spectrum signal acquisition system consisting of a spectrum signal acquisition light path unit and a weak signal conditioning circuit, and a double laser precise ranging system. The modulation frequency of the light source is 1 KHz, the central wavelength of the filter is 730 nm and 810 nm, and the bandwidth is 10 nm. The light source system of the crop canopy reflectance spectrum sensor emits 730 nm of constant light intensity, 810 nm modulated spectral signal to irradiate the crop canopy, and the spectral signal acquisition system receives the modulated spectral signal reflected by the crop canopy to obtain the intensity of the crop canopy reflectance spectrum. Thirdly, according to the output signal of crop canopy reflectance spectrum sensor and the need of field test, this paper uses ATmega32 integrated with ADC module as the core control chip, with temperature and humidity sensor, keyboard. Input, LCD display, acoustooptic reminder, SD card storage and power management and other components of the control part of the hardware circuit; C language design embedded control software to achieve crop growth information collection, display and storage, using SolidWorks designed the monitor structure diagram, and according to the structure diagram of the monitor for mechanical processing. The function test includes stability test, anti-light interference test, return error test, calibration test and temperature performance test, and field test includes reflectance test, crop growth information test and leaf area index test. The results of functional test and field test show that the designed crop growth information monitor has good performance and can meet the needs of fast and accurate acquisition of crop growth information.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S126

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