Research On Real Time Online And Intelligent Detection Measurement Of Plant Water Content

The detection of plant water content is a important research field of agriculture and forestry enginerring.At present,the detection measurements based on physiological indexes or physical characteristics exisit some disadvantages.In order to satisfy the requirements of modern agriculture and forestry preferably,two intelligent detection measurements are presented based on machine vision and standing wave ratio method,which possess undamage,real time and online specialties.The research lays the foundation of precision irrigation,facility agriculture and plant physiological information interpretation.The main contents and innovation points are as follows:(1)Different degrees of plant leaf wilting are regarded as a series of visual phenomena.So plant is supposed to a sort of living sensor.The 3D point cloud data of plant leaf is regarder as surfaces with different curvature in the Euclidean space.Firstly the wilting index L2DFT and LDBM are respectively defined based on 2D discrete time Fourier transform and double blanket method in fractal theory.Then laser triangulation method and time-of-flight method are selected as the critical sensor techniques via the merit and demerit of frequently-used 3D plant phenotype acquisition technology.Finally computing process of wilting index is excogitated based on image processing.(2)The experiments based on laser triangulation method indicate the mapping relationship between wilting index and plant leaf wilting degree,and the correlation of wilting index and vapor pressure deficit(VPD)or photosynthetically active radiation(PAR).The research demonstates that wilting index could express the degree of leaf wilting commendably for pumpkin,gourd,pumpkin and okra.Furthermore,a real time identificaiton method based on ToF camera is raised via qualitative and quantitative analysis of different wilting degrees of plant leaf.(3)Non-destructive testing of plant stem water content based on standing wave ratio method is certified reliably by theoretical analysis of plant dielectric property.Stem water content change in the range of detection rings leads to the change of dielectric constant.Then dielectric constant change leads to the change of impedance,causing the standing wave ratio changing,ultimately leading to the variation of transmission line voltage.So by testing transmission line voltage,plant stem water content can be measured.The experiments indicate that when stem water content is a constant and less than 59.59%and diameter of detection ring is a constant and less than 10.5 cm,the measuring equipment can fit the application requirement.(4)Under the circumstance of imparity water deficit stress,stem water content of pine tree,peach,aspen,crape mytle,pachira macrocarpa et al.Meanwhile,the correlation of plant stem water content and minienvironment like VPD,PAR,physiological parameter like sap flow velocity,net photosynthetic rate.And under the condition of zero degree,mutation rule of plant stem water content is monitored.