| The tobacco industry is one of pillar industries of Guizhou Province, but the crop is controlled strictly by national index.The landform of Karst plateau mountainous area be reduced to fragments and crop cultivation complex so on, so it is difficult to through the traditional means to achieve rapidly monitoring of tobacco growing status and layout.Then now accurateand and rapid of Remote sensing monitoring method is the trend of Guizhou tobacco industry development.With the Sound and rapid development of remote sensing technology,multi-spectral remote sensing has been widely used in agricultural condition monitoring.However, the cloudy and rainy climate characteristics of Guizhou resulting in the tobacco growth period is very difficult to obtain effective multi-spectral data.Synthetic Aperture Radar(SAR) with the ability of penetrating fog and clouds of all day and round-the-clock shooting has become the new favorite of agricultural monitoring.The paper based on the principle and technology method of radar remote sensing monitoring,and take the country modern tobacco agricultural base unit in Guizhou as the study area,take the tobacco as the research object,take 2013 dual polarized Terra SAR-X and 2014 fully polarized Radarsat-2 as the research data,then using the different methods and polarization combinations to identify the tobacco of Guizhou plateau mountain area.Filtering and geometric correction so on were made.On the one hand,ground backscattering characteristics wereanalyzed, and combining with the related data of the radar image recognition of tobacco;On the other hand, combined with sampling data and field investigation data verification the recognition accuracy,study on method of improving crop remote sensing recognition ability.there are some main conclusions obtained:(1) The tobacco VV polarization backscatter coefficient is smaller than HH polarization backscatter coefficient, because the tobacco is in the rosette stage of tobacco growth period, leaves has been fully expanded, plant canopy attenuation the penetration ability of VV polarization penetration. Rice of the backscattering coefficient is greater than the tobacco in HH polarization, which is the result of interaction of vertical rice plants and the water layer.With the growth of tobacco, tobacco backscattering coefficient decreased.(2) In the study area, corn and other features has some interference to identify the tobacco, this is because the growth cycle, the scattering characteristics of maize and tobacco are similar; in addition,rocky desertification phenomenon as well as a handful of coated tobacco field also has a certain influence on tobacco identification.(3) Based on full polarization radar data tobacco recognition accuracy reaches 87.23%, better than based on the dual polarization ratio of polarization and polarization difference accuracy,to meet the basic needs of the crop monitoring. At the same time,the terrain is an important factor on affecting the accuracy of recognition.Multi-phase, multi-polarization and even with the use of multi-source data is the main research direction of crop identification in plateaumountainous area in the future,and the new mining methods can not be ignored. The results of the study show that, in the mountainous area of Guizhou plateau, crop identification and area calculation by radar remote sensing is feasible both in theory and practice, and will become an important data source for crop monitoring in the area.Object recognition is the basis of crop condition monitoring,it has important significance to use high resolution synthetic aperture radar(SAR) for accessing real-time large-scale agricultural crop growth status,establishing the basic,the frontier and the public welfare recognition system of modern agricultural production,and promoting the scale,intensive development of Guizhou modern agriculture. |
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