CANOPY GEOMETRY IDENTIFICATION BY BIDIRECTIONAL CANOPY REFLECTED SPECTRUM
Investigations have been made on identification of erective, middle and horizontal varieties by bidirectional canopy reflected spectrum in wheat.There are two methods for identification crop geometry parameters, one was by the bidirectional canopy reflectance and different wavebands and view angles, the bidirectional reflectance of visible and near infrared bands at 15°, 30°and 45°field of view for the main viewing plane could be used for identification of plant structural types based on bidirectional data. For erective varieties, the bidirectional canopy reflectance at near infrared was f45°＞fl5°＞ f30°, at visible band was f45o＞fl5°≈f30°; For middle varieties, the bidirectional canopy reflectance at near infrared and visible band was fl5o＞f45°＞ f30°; For horizontal varieties, the bidirectional canopy reflectance at near infrared and visible band was f45o＞f30°＞ f15°.The other method was by inversion of semi-empirical BRDF models. The structure parameter sensitive index (SPEI) which basedon the weight for the volumetric kernel (fvol), the weight for the geometric kernel (fgeo), and the weight for constant corresponding to isotropic reflectance (fiso) was defined in this study for crop geometryidentification. SPEI was proved to be more sensitive to identify crop geometry structures than structural scattering index (SSI) and normalized difference f-index (NDFI), SPEI could be used to distinguish erective, middle and loose geometry varieties. So, it is feasible to identify horizontal, middle and erective varieties of wheat by multi-temporal and bidirectional canopy reflected spectrum.
winter wheat bidirectional canopy reflectance crop canopy geometry
Wenjiang Huang Jihua Wang Liangyun Liu Zhihong Ma Zhijie Wang Yi Tang Xuzhang Xue
National Engineering Research Center for Information Technology in Agriculture, Beijing, 100089, China
国际会议
北京
英文
205-208
2005-10-14（万方平台首次上网日期，不代表论文的发表时间）