Influences of Leaf-Specular Reflection on Canopy BRF Characteristics: A Case Study of Real Maize Canopies With a 3-D Scene BRDF Model
Influences of Leaf-Specular Reflection on Canopy BRF Characteristics: A Case Study of Real Maize Canopies With a 3-D Scene BRDF Model
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叶子镜面反射对冠层 BRF 特性的影响：基于 3-D 场景 BRDF 模型的真实玉米冠层案例研究
DOI：
10.1109/tgrs.2016.2598442
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发表时间：
2017-02
影响因子：
8.2
通讯作者：
Zhu Qijiang
中科院分区：
文献类型：
--
作者：
Xie Donghui;Qin Wenhan;Wang Peijuan;Shuai Yanmin;Zhou Yuyu;Zhu Qijiang
The diffuse and specular components of leaf reflection are both important to determine the leaf optical properties as well as to describe the leaf bidirectional reflectance distribution function (BRDF). However, the specular component is usually ignored in practice in numerous canopy reflectance models that describe the interaction between solar light and vegetated scene components. To evaluate the impact of leaf-specular reflection on canopy bidirectional reflectance factor (BRF) characteristics, we introduce a leaf BRDF model into the radiosity-graphics combined model (RGM; a 3-D scene model) to calculate canopy BRFs with nondiffuse leaves. The modified RGM is validated by comparing simulated BRFs against in situ measured BRFs over real maize canopies. The results show that ignorance of leaf-specular reflection can result in up to 50% of relative error in the blue band (435.8 nm). A series of maize canopies with different leaf angle distributions (LADs) is reconstructed to investigate the effect of five major biophysical/geometrical parameters such as leaf area index, LAD, leaf surface property, view direction, and solar zenith angle on leaf-specular reflection contributions to the canopy BRF. It is demonstrated that increasing the incident solar zenith angle and decreasing the mean leaf angle impact the angular distribution of the canopy BRF more significantly than other factors. The cumulative hemispherical relative and absolute errors of canopy BRF caused by the leaf-specular reflection are often too large to be ignored, even for canopies with rough surface leaves. Moreover, the relative error of BRF in visible waveband shows that, in general, leaf-specular reflection has a large impact than that in near-infrared waveband. However, such impact can be sufficiently accounted for by even just consideration of the first-order leaf-specular reflection in canopy reflectance calculation, leading to a substantial improvement in simulation accuracy for most vegetation canopies.
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DOI：
10.1145/37401.37438
发表时间：
1987-08
期刊：
Proceedings of the 14th annual conference on Computer graphics and interactive techniques
影响因子：
--
作者：
J. R. Wallace;Michael F. Cohen;D. Greenberg
通讯作者：
J. R. Wallace;Michael F. Cohen;D. Greenberg
DOI：
10.1016/j.jqsrt.2008.09.001
发表时间：
2009
影响因子：
2.3
作者：
J. Stuckens;B. Somers;S. Delalieux;W. Verstraeten;P. Coppin
通讯作者：
J. Stuckens;B. Somers;S. Delalieux;W. Verstraeten;P. Coppin
DOI：
10.6028/nbs.mono.160
发表时间：
1977-10
期刊：
--
影响因子：
--
作者：
F. E. Nicodemus;J. Richmond;J. Hsia;I. Ginsberg;T. Limperis;Sidney Harman;Jordan J Baruch
通讯作者：
F. E. Nicodemus;J. Richmond;J. Hsia;I. Ginsberg;T. Limperis;Sidney Harman;Jordan J Baruch
影响因子：
13.5
作者：
J. Ross;A. Marshak
通讯作者：
J. Ross;A. Marshak
DOI：
--
发表时间：
2002
期刊：
Acta Agronomica Sinica
影响因子：
--
作者：
Wu Men
通讯作者：
Wu Men