赵娟, 黄文江, 张耀鸿, 景元书, 宋晓宇, 杨贵军, 张清, 孙雷刚. 不同株型小麦的双向反射分布函数特征研究[J]. 农业工程学报, 2014, 30(9): 157-167. DOI: 10.3969/j.issn.1002-6819.2014.09.020
    引用本文: 赵娟, 黄文江, 张耀鸿, 景元书, 宋晓宇, 杨贵军, 张清, 孙雷刚. 不同株型小麦的双向反射分布函数特征研究[J]. 农业工程学报, 2014, 30(9): 157-167. DOI: 10.3969/j.issn.1002-6819.2014.09.020
    Zhao Juan, Huang Wenjiang, Zhang Yaohong, Jing Yuanshu, Song Xiaoyu, Yang Guijun, Zhang Qing, Sun Leigang. Study on bidirectional reflectance distribution function features of wheat with different plant type[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2014, 30(9): 157-167. DOI: 10.3969/j.issn.1002-6819.2014.09.020
    Citation: Zhao Juan, Huang Wenjiang, Zhang Yaohong, Jing Yuanshu, Song Xiaoyu, Yang Guijun, Zhang Qing, Sun Leigang. Study on bidirectional reflectance distribution function features of wheat with different plant type[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2014, 30(9): 157-167. DOI: 10.3969/j.issn.1002-6819.2014.09.020

    不同株型小麦的双向反射分布函数特征研究

    Study on bidirectional reflectance distribution function features of wheat with different plant type

    • 摘要: 为了获得高精度的农作物生理生化参数的遥感反演结果和冠层结构信息提取,由多年地面观测的多角度数据结合半经验的二向性反射分布函数(bidirectional reflectance distribution function,BRDF)核驱动模型,利用红光(680 nm)和近红外波段(860 nm)的6个BRDF形状指示因子,分析了紧凑型小麦J411和披散型小麦Z9507的BRDF特征。研究表明:主平面上2种株型小麦的方向性反射率表现不同,拔节期披散型小麦的二向NDVI(normalized difference vegetation index)大于紧凑型小麦;红光波段紧凑型小麦J411的几何光学核系数大于披散型小麦Z9507,紧凑型小麦几何光学效应更强;近红外波段披散型小麦体散射核系数大于紧凑型小麦,披散型小麦体散射效应更强。由此表明多角度观测数据更适于分析小麦冠层结构信息。该研究为多角度遥感在精准农业领域的应用提供参考。

       

      Abstract: Abstract: Canopy structural property is a noticeable factor that exerts a certain influence on canopy bidirectional reflectance, thus it is primarily significant to detect a crop structure signature to refer to quantified remote sensing. This paper analyzed the variations in bidirectional reflectance of erective wheat J411 and loose wheat Z9507 under different solar zenith angles and viewed zenith angles in a solar principal plane. What's more BRDF (Bidirectional Reflectance Distribution Function) features for the two varieties were explored by exploiting six BRDF shape indictors in a red band (680 nm) and NIR (Near Infrared) band (860 nm) based on the semi-empirical BRDF kernel model and 25 field-measured multi-angle datasets from three years during the year 2003-2004、2004-2005, and 2008-2009. The results showed that during the jointing stage, the sensitive stage to identify canopy geometry, Z9507 conceived a larger bi-NDVI (Bidirectional Normalized Difference Vegetation Index) than J411 in a solar principal plane, that means the loose wheat held a larger coverage than the erective variety. Performances of six anisotropic indices differed in varieties and bands. For the erective variety, both ANIF and ANIX in the red band were slightly higher than the loose wheat, while in the NIR band the values for loose wheat exceeded the erective variety. Meanwhile, a similar variation trend presented for the two varieties was that the ANIX was always higher than the ANIF in two bands and values of the two indices in NIR band were larger than that in the red band for both two varieties. Referring to AFX, it displayed a different variation trend compared with ANIF and ANIX. Its values fluctuated around 1. In the red band, the AFX for two varieties were almost less than 1, and in the NIR band were beyond 1, which explicitly depicted the dominance of canopy geometric scattering in the red band and volumetric scattering in the NIR band. Moreover, in the red band the AFX of erective wheat was slightly higher than the loose wheat, while in the NIR band the AFX of loose wheat outweighed erective wheat. Therefore, it is concluded that the geometric weights of an erective variety in the red band are more significant than the loose variety, indicating a stronger geometric effect in the red band for erective wheat; and in the NIR band higher volumetric weights are for the loose variety, suggesting a stronger volumetric effect in the NIR band for loose wheat. Finally, it was illustrated that the anisotropic indices are more capable and applicable to extract crop canopy structural information.

       

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