基于LabVIEW的電容式植物水分檢測(cè)儀的軟件設(shè)計(jì)
Software Design of Capacitive Plant water detector based on LabVIEW

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摘 要
水分是植物生命活動(dòng)中不可缺少的。農(nóng)田缺水會(huì)導(dǎo)致作物產(chǎn)量和土地生產(chǎn)力的下降，水資源的缺乏是遏制農(nóng)業(yè)發(fā)展的重要因素。我國(guó)農(nóng)業(yè)生產(chǎn)過(guò)程中，普遍采用監(jiān)測(cè)土壤濕度來(lái)間接監(jiān)測(cè)植物的含水情況，由于這種監(jiān)測(cè)技術(shù)存在一定的滯后性，容易造成灌溉利用的不合理和水資源浪費(fèi)。一些發(fā)達(dá)國(guó)家采用直接監(jiān)測(cè)植物體的含水情況來(lái)指導(dǎo)精量灌溉，可以達(dá)到節(jié)水 35％、增產(chǎn) 40％的效果。因此，準(zhǔn)確判斷作物水份虧缺程度可以指導(dǎo)合理灌溉，促進(jìn)精細(xì)農(nóng)業(yè)發(fā)展。
本課題所研究的植物水分檢測(cè)儀可以用來(lái)準(zhǔn)確判斷植物體內(nèi)水份虧缺程度，從而為確定合理的灌溉時(shí)間和灌水量做參考，實(shí)現(xiàn)發(fā)展節(jié)水農(nóng)業(yè)，提高水資源的利用率的目的。本文基于虛擬儀器的基本結(jié)構(gòu)及信號(hào)處理的概念，設(shè)計(jì)了電容式植物水份分析儀的信號(hào)處理系統(tǒng)。并能對(duì)植物電信號(hào)進(jìn)行時(shí)域分析以及頻譜分析，同時(shí)對(duì)相關(guān)數(shù)據(jù)進(jìn)行線性擬合，從而找出植物葉片水分與電信號(hào)的內(nèi)在聯(lián)系。課題研究表明，植物體內(nèi)水分的含量越高，電信號(hào)就越強(qiáng)。測(cè)量所得的電壓和植物體內(nèi)的水分含近似于線性關(guān)系。

關(guān)鍵詞：虛擬儀器 時(shí)域分析 頻譜分析 線性擬合

Abstract
Water is the plant life activities indispensable. Farm water shortages will lead to a decline in crop yields and land productivity , lack of water is an important factor to curb agricultural development. China's agricultural production process, commonly used to monitor soil moisture to water the plants for indirect monitoring , because of this monitoring technology exists a certain lag , likely to cause unreasonable use of irrigation and water waste. Some developed countries using direct monitoring of plant water situation to guide precision irrigation , water conservation can be achieved by 35% , an increase of 40% of the effect. Therefore , to accurately determine the extent of crop water deficit can guide rational irrigation , promote the development of precision agriculture .



The topics studied plant water detector can be used to accurately determine the extent of plant water deficit in vivo, and thus a reference to determine the reasonable amount of irrigation time and irrigation, water-saving agriculture to achieve development, the purpose of improving the utilization of water resources. In this paper, the concept of basic structure and signal processing based on virtual instrument is designed capacitive plant moisture analyzer signal processing systems. And can be time-domain analysis of plant electrical signal and spectrum analysis, and linear fit to the data, in order to identify the intrinsic link leaf moisture and electrical signals. Research shows that the higher the moisture content in plants, the stronger signals. Moisture measurement voltage and the resulting plants containing approximately linear relationship.
Keywords：Virtual Instrument Analysis in time domain Spectrum Analysis Linear fit

目 錄

第一章 緒論 1
1.1 研究目的和意義 1
1.2 國(guó)內(nèi)外技術(shù)現(xiàn)狀及發(fā)展趨勢(shì) 2
1.3 虛擬儀器的優(yōu)勢(shì) 4
1.4 本設(shè)計(jì)主要內(nèi)容和章節(jié)結(jié)構(gòu)安排 5
1.5 小結(jié) 5
第二章 實(shí)驗(yàn)平臺(tái)構(gòu)建 6
2.1 LabVIEW的基本概述 6
2.2 G語(yǔ)言簡(jiǎn)介 7
2.3 LabVIEW 模塊分析 7
2.3.1 工具選板 8
2.3.2 控件選板 8
2.3.3 函數(shù)選板 9
2.4 數(shù)據(jù)采集 10
2.4.1 聲卡的作用 10
2.4.2聲卡的硬件結(jié)構(gòu) 11
2.4.3聲卡的主要技術(shù)參數(shù) 12
2.5 小結(jié) 13
第三章 系統(tǒng)的總體設(shè)計(jì) 14
3.1 系統(tǒng)的主要功能 14
3.2系統(tǒng)總體框架 14
3.3系統(tǒng)總體結(jié)構(gòu) 15
3.4 小結(jié) 16
第四章 系統(tǒng)功能與實(shí)現(xiàn) 17
4.1 信號(hào)采集模塊 17
4.2濾波器 19
4.3 頻譜分析模塊 20
4.4 時(shí)域參數(shù)測(cè)量 23
4.5 曲線擬合 24
4.6 小結(jié) 25
第五章 系統(tǒng)調(diào)試與實(shí)驗(yàn) 26
5.1 采集到的信號(hào)波形顯示 26
5.2 濾波后的信號(hào)顯示 26
5.3 頻譜分析 27
5.4 數(shù)據(jù)擬合 28
5.5 小結(jié) 29
第六章 總結(jié)與展望 30
致謝 31
參考文獻(xiàn) 32