基于WSN的油菜生长环境数据采集系统

针对传统作物生长环境数据获取手段实时性差、劳动强度大以及部署微型自动气象站和商用Zigbee产品成本高、开放性较差等问题，设计并实现了一种基于WSN的油菜生长环境数据采集系统。提出了轻量级的能量感知路由协议CLFP，并给出了软硬件的相关设计方法。仿真和大田试验结果表明，系统温度采集精度最高可达0.01 ℃，测湿精度达±5%，光强采集范围为1~65 535 lx，可并发的数据传输达到36路，可满足农业现场环境数据的较高测量要求。在标称电源供电情况下，系统实际有效生存周期超过142 d，由于采用AT89C51和nRF2401作为基础硬件平台，成本低廉，有助于大规模部署和应用。     

农田信息采集单多跳共存LEACH算法

针对农田环境信息量丰富的特点,提出一种基于LEACH算法的改进型无线传感器网络路由算法--LEACH-SMC.在LEACH-SMC算法的稳态阶段,簇头节点到基站间通信采用临界距离来判断和选择多跳或单跳方式,在多跳方式中采用基于最小能量消耗的路由方式.应用Matlab对LEACH-SMC算法和LEACH算法进行仿真对比分析,结果表明, LEACH-SMC算法能提高网络有效覆盖面积并延长整个网络的寿命.     

奶牛场无线传感器网络设计研究

针对奶牛养殖场数据采集时不易实现检测区域的完全覆盖和铺设线缆繁琐的问题,设计了由高性能、低功耗单片机ATmega32L和无线通信模块CRM2400CNC,建立奶牛养殖场无线传感器网络。同时,重点讨论了系统结构、传感器节点的硬软件设计和通信协议等关键问题,结合奶牛场的实际对系统结构的简化进行了研究,并提出了一种新的适合动态网络的跨层技术。试验结果表明,该系统具有结构简单、成本低、功耗低等特点。     

基于激光反射的土壤表面粗糙度测量装置设计与试验

为了实时获取土壤表面粗糙度数据,设计了一种基于激光三角测距原理的土壤表面粗糙度专用测量装置.采用激光扫描测距仪测量微位移,其精度高、响应速度快,测距分辨力高达0.1 mm,显著提高了土壤表面粗糙度的测量精度;借助于光电编码盘和螺杆组合实现高精度扫描定位;PDA作为上位机,农田环境下具有方便携带,大容量存储数据和智能化实时处理功能等优点.     

A calibration method of detecting soil water content based on the information-sharing in wireless sensor network

In agricultural production, there is contradiction between the cost and accuracy of detection during the course of acquiring soil water content (θ) online. This conflict is one of the core issues of automatic water-saving irrigation technology in agriculture. At the same time, capacitive soil moisture sensor (CSMS) has received considerable attention, for it can acquire θ with low cost and high precision, and meet the application requirements of wireless sensor network (WSN). But CSMS is vulnerable to the soil temperature (T_s) and salinity (S_s) in the measurement process. Therefore, this study took EC-5 sensor for example to establish water detection calibration models of soil temperature and salinity for single sensor, using Least Squares Support Vector Machines on MatLAB (LS-SVMlab) as the tool. On this basis, we explored the spatial variability of T_s and S_s, and then a method, which could be used to calibrate the output signals of sensors in multi-point network, was proposed based on the information-sharing (T_s or S_s) technology of WSN. Through laboratory experiment, we effectively reduced the impact of soil temperature and salinity on the single sensor. In example analysis, we investigated the detection precision and costs under different information-sharing radiuses (r). And the results indicated that the method we proposed based on the information-sharing technology of WSN could successfully calibrate the influence of soil temperature and salinity on sensors in multi-point network, and it was an efficacious approach to determine the balance between the calibration accuracy of moisture sensor and the investment of agricultural production. For example, while the calibration precision of soil temperature and salinity is respectively 1%, the costs can be reduced by 30%.     

基于无线传感网络的果园环境信息监测系统研究

影响果树生长的因素有多种,其中至关重要的因素有光照、土壤湿度、温度等,对果园环境信息进行实时监测是实现果园管理现代化的重要手段。基于无线传感网络的果园环境信息监测系统是由不同的传感器收集不同的数据信息,并通过终端发送到协调器,协调器收到终端的环境数据后再通过串口连接至电脑;经过数据处理模块处理后,通过上位机控制软件实时显示环境数据,并且通过显示控制软件远程控制继电器。应用基于无线传感网络的果园环境信息监测系统不仅能够保证果园环境数据的实时性和有效性,也能帮助果农及时对环境变化做出正确的应对决策。     

马齿形玉米种子尖端激光定向与胚面识别装置研制

为了实现玉米种子的尖端定向与胚面识别,该文以现有尖端定向装置输出的马齿型玉米种子为对象,基于激光开关和测距原理,提出了一种尖端定向与胚面识别方法:依据马齿形玉米种子尖端窄大头宽的轮廓特征,利用激光开关传感器等部件对玉米种子的尖端朝向进行识别,并将大头朝前的玉米种子进行剔除;依据马齿形玉米种子胚面上有胚沟而反面较为平整的表面特征,利用激光测距传感器等部件对尖端朝前的玉米种子进行胚面识别。设计并搭建了玉米种子尖端定向与胚面识别装置,配合现有的尖端定向装置进行试验,结果表明:尖端定向与胚面识别装置的尖端定向成功率达到99.1%,相比现有的尖端定向装置提升了9.5个百分点,胚面识别准确率为96.4%。该方法基本可以实现玉米种子的尖端定向,同时保证胚面识别准确率达到较高水准。该文提出的玉米种子尖端定向与胚面识别方法可为后续玉米种子的自动化定向包装提供参考。     

马铃薯薄片干燥过程形态变化三维成像

为研究马铃薯薄片在干燥过程中形态变化规律,该文利用Kinect传感器搭建了图像采集平台,研究其在不同干燥温度下(50、60、70、80℃)的形态变化规律。通过图像采集平台获取马铃薯薄片深度图像和彩色图像,利用彩色图像确定感兴趣区域,对对应区域的深度图像进行灰度值拉伸、阈值分割、边缘去噪处理,进而提取特征,计算出正投影面积的收缩率、深度均值及标准差,以表征马铃薯干燥过程中表面卷曲及平整度等形态指标的变化规律。对不同干燥时间点马铃薯片进行三维图形显示可观察其变化规律明显。统计结果表明:低温(50、60℃)与高温(70、80℃)对马铃薯薄片干燥时的收缩率、卷曲程度具有显著影响(P0.05)。50℃时收缩率为54.97%,80℃时收缩率升高为64.55%;干燥温度与马铃薯片卷曲程度呈先升后降的关系,60℃时卷曲度最大,其深度均值为27.81 mm,80℃时降低到18.86 mm。而四组温度下,马铃薯薄片的平整度具有显著性差异(P0.05),50℃时马铃薯片深度值的标准差为7.99 mm,80℃时降低至5.71mm,说明平整度随着干燥温度升高而增加。该研究可为马铃薯薄片干燥过程中形态变化的检测提供参考,同时为干燥工艺的智能化控制提供技术依据。     

平行极板电容传感器介电式颗粒饲料水分检测仪设计与试验

为了实现颗粒饲料含水率的快速、无损检测,设计了以STM32F103ZET6单片机为控制芯片的颗粒饲料水分检测仪,采用平行极板电容传感器、温度传感器、质量传感器和相应的检测电路分别检测颗粒饲料样品的电容、温度和容积密度,经过单片机进行处理后实现颗粒饲料的含水率检测,并在OLED显示屏上显示检测结果。采用自制颗粒饲料水分检测仪,分析了含水率、温度、容积密度对颗粒饲料相对介电常数的影响规律,并建立了相对介电常数与含水率、温度、容积密度之间的关系模型,模型的决定系数为0.996 8。同时对颗粒饲料水分检测仪的检测精度进行了检验,含水率实测值与仪器检测值之间的决定系数为0.990 3。试验结果表明,与烘干法相比,所设计检测仪的绝对测量误差值在±0.6%以内,具有一定的实用价值。该研究为颗粒饲料水分快速、无损在线检测提供一种新的方法和技术支撑。     

High resolution satellite imaging sensors for precision agriculture

The central concept of precision agriculture is to manage within-field soil and crop growth variability for more efficient use of farming inputs. Remote sensing has been an integral part of precision agriculture since the farming technology started developing in the mid to late 1980s. Various types of remote sensors carried on ground-based platforms, manned aircraft, satellites, and more recently, unmanned aircraft have been used for precision agriculture applications. Original satellite sensors, such as Landsat and SPOT, have commonly been used for agricultural applications over large geographic areas since the 1970s, but they have limited use for precision agriculture because of their relatively coarse spatial resolution and long revisit time. Recent developments in high resolution satellite sensors have significantly narrowed the gap in spatial resolution between satellite imagery and airborne imagery. Since the first high resolution satellite sensor IKONOS was launched in 1999, numerous commercial high resolution satellite sensors have become available. These imaging sensors not only provide images with high spatial resolution, but can also repeatedly view the same target area. The high revisit frequency and fast data turnaround time, combined with their relatively large aerial coverage, make high resolution satellite sensors attractive for many applications, including precision agriculture. This article will provide an overview of commercially available high resolution satellite sensors that have been used or have potential for precision agriculture. The applications of these sensors for precision agriculture are reviewed and application examples based on the studies conducted by the author and his collaborators are provided to illustrate how high resolution satellite imagery has been used for crop identification, crop yield variability mapping and pest management. Some challenges and future directions on the use of high resolution satellite sensors and other types of remote sensors for precision agriculture are discussed.