变量灌溉处方图设计中无人机飞行高度和起飞时间确定  

Determination of UAV altitude and take-off time in the design of a variable rate irrigation prescription map

作　　者：祝长鑫 赵伟霞[1] 单志杰[1] 李久生[1] ZHU Changxin;ZHAO Weixia;SHAN Zhijie;LI Jiusheng(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100048

出　　处：《农业工程学报》2023年第5期61-69,F0003,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划项目(2022YFD1900805);国家自然科学基金面上项目(51979289);流域水循环与调控国家重点实验室自由探索课题(SKL2022TS03)。

摘　　要：无人机热成像系统快速获取农田水分亏缺信息空间分布的特点为变量灌溉动态分区管理提供了监测平台。为了提高利用无人机热成像系统生成变量灌溉处方图的精度,该研究提出热成像系统获取的红绿蓝3色值与温度间的转化方法,分析了无人机热成像系统飞行时刻和飞行高度对冠层温度空间分布和变量灌溉处方图生成的影响。试验在河北邢台大曹庄管理区水肥一体化试验基地开展,无人机热成像系统飞行高度设置为70、90和110 m,起飞时间选择在08:00、11:00、14:00和17:00,飞行区域为三跨加悬臂圆形喷灌机控制灌溉面积的1/4。结果表明,RGB颜色值与温度间存在极显著的线性关系(P<0.01)。无人机热成像系统的起飞时间对冠层温度空间分布有较大影响,在11:00和14:00飞行时冠层温度空间分布差异最大,变量灌溉处方图内总灌水量相对较小。随着无人机热成像系统飞行高度的增加,图像分辨率降低,变量灌溉处方图内总灌水量呈增大趋势,90和110m飞行高度时的总灌水量平均比70m时分别高6.1%和12.1%。在利用无人机热成像系统获取变量灌溉处方图时,推荐冬小麦生育期内飞行时间为11:00—15:00,夏玉米为11:00—16:00。研究为保障基于无人机热成像系统的华北平原冬小麦、夏玉米变量灌溉处方图设计精度提供技术支撑。Unmanned aerial vehicle(UAV)thermal imaging can serve as anexcellent platform torapidly obtain the spatial distribution of crop canopy temperature(CT)for dynamic variable rate irrigation(VRI).This study aims to improve the spatial distribution accuracy of crop water deficit using UAV thermal imaging.A conversion model between S RGB and CT was established to clarify the effects of flight altitude and take-off time on the spatial distribution of CT.The experiment was conducted at the water and fertilizer integration experimental base in Dacaozhuang,Hebei Province of the North China Plain(36°28'12"N,114°54'01"E).The UAV flight area was 1.78 ha under a three-span center-pivot irrigation system with an overhang.The experimental crops were taken as winter wheat and summer maize in 2022.Three procedures were used to determine the relationships between temperature and S RGB.Firstly,the temperature and S RGBwere displayed in the nine single photos.Secondly,the temperature and S RGB were extracted as the black body fromthe nine different temperature values,and then their photos were captured with the thermal imaging camera.Thirdly,the CT was measured with the nine stationary infrared thermometers(IRTs)that were installed in the experimental field.As such,theSRGB was obtained in these locations by the UAV thermal imaging system.In the field test,the flight date was selected in sunny and windless weather and then started at 08:00,11:00,14:00 and 17:00 with a flight altitude of 70 m and a flight period of 20 min.The flight altitude was set as 70,90,and 110 m,according to the cruising ability of the UAV.The flight date was chosen on May 22,May 28,and June 1 at the grain-filling stage for the winter wheat,whereas,the summer maizewas on August 2,August 17,and September 13 from the twelfth leaf stage to the milk stage.The reason was that the crop canopy coverage posed some influence on the accuracy of CT during the thermal imaging system,in terms of take-off time in the experiments.The flight date was also selected on July 18,1

关 键 词：无人机 作物 温度 热成像 变量灌溉 处方图 

分 类 号：S274.3[农业科学—农业水土工程]