该文构建了光子在作物冠层传输的随机过程,采用蒙特卡罗(M on te C arlo)方法模拟了作物冠层BRDF。对比蒙特卡罗模型和M CRM模型,分析了叶倾角(LAD)与叶面积指数(LA I)对两模型BRDF的影响,并对其中的变化给出了合理的解释。研究表明,两...该文构建了光子在作物冠层传输的随机过程,采用蒙特卡罗(M on te C arlo)方法模拟了作物冠层BRDF。对比蒙特卡罗模型和M CRM模型,分析了叶倾角(LAD)与叶面积指数(LA I)对两模型BRDF的影响,并对其中的变化给出了合理的解释。研究表明,两模型虽然在模拟的BRDF数值上有一定差异,但在不同LAD和LA I对BRDF的变化趋势上达到了较好的一致性。最后,用实测BRDF数据验证和分析蒙特卡罗模型,结果表明,蒙特卡罗模型与实测BRDF较为吻合,蒙特卡罗模型可以作为其他作物冠层BRDF前向模拟的有效验证工具。展开更多
TB96 2000064137真空紫外反射率计用于BRDF的测量=Measurementof BRDF by using the VUV reflectomters[刊,中]/唐玉国,齐文宗,李福田(中科院长春光机所应用光学国家重点实验室.吉林,长春(130022))//光学技术.—1999,(3).—51-53,55介...TB96 2000064137真空紫外反射率计用于BRDF的测量=Measurementof BRDF by using the VUV reflectomters[刊,中]/唐玉国,齐文宗,李福田(中科院长春光机所应用光学国家重点实验室.吉林,长春(130022))//光学技术.—1999,(3).—51-53,55介绍了一种真空紫外反射率计,采用间接测量方法,用该反射率计测试了聚四氟乙烯漫反射板的双向反射率分布函数(BRDF),正入射时该聚四氟乙烯漫反射板15°到75°的双向反射率分布函数偏差为13%。(方舟)展开更多
目标双向反射分布函数BRDF (Bidirectional Reflectance Distribution Function)不仅是陆面遥感的关键地球物理参数,也是星载光学遥感仪器基于地面目标的场地辐射校正重要参量,是影响定标精度的关键要素。传统野外地物多角度测量使用的...目标双向反射分布函数BRDF (Bidirectional Reflectance Distribution Function)不仅是陆面遥感的关键地球物理参数,也是星载光学遥感仪器基于地面目标的场地辐射校正重要参量,是影响定标精度的关键要素。传统野外地物多角度测量使用的观测设备,一般其结构较为复杂,重量体积较大,而且运输和组装过程繁琐,观测目标时容易受地形和交通限制,难以进行高效快速精确的野外测量。近年来,无人机由于其设备操作简便、运输和观测方式灵活等方面的优点,可作为新的观测平台应用于当前遥感试验中。本文设计了一种基于无人机平台的地表BRDF测量装置、观测方案和数据处理流程。利用多旋翼低空无人机和云台的组合,搭载野外地物光谱仪和跟拍相机,通过对地面目标多角度观测和高精度定位及角度控制,实现针对固定目标的多方位角和天顶角观测。本文采用上述设计方案和观测流程,在敦煌辐射校正场开展多次稳定均匀沙漠目标的多角度光谱观测试验,并利用实验观测数据,基于Ross-Li核驱动模型推算了场地BRDF模型参数,并与MODIS的陆表BRDF产品(MCD43C1)及反射率产品(MOD/MYD09)进行对比验证。通过开展野外实验,核验了这种新的BRDF观测手段的可靠性,获取的敦煌地表BRDF参数与MODIS遥感产品有良好的一致性,各波段的相对偏差在5%以内。本研究表明,基于多旋翼无人机的BRDF观测系统,提供了一种全新的地物目标方向反射特性观测方法,可用于自动化高频次场地特性观测以及卫星同步定标等野外实验活动。在保证观测精度的同时,极大地减轻人力物力的投入,值得广泛推广应用。展开更多
Row sowing is a basic crop sowing method in China,and thus an accurate Bidirectional Reflectance Distribution Function (BRDF) model of row crops is the foundation for describing the canopy bidirectional reflectance ch...Row sowing is a basic crop sowing method in China,and thus an accurate Bidirectional Reflectance Distribution Function (BRDF) model of row crops is the foundation for describing the canopy bidirectional reflectance characteristics and estimating crop ecological parameters.Because of the macroscopically geometric difference,the row crop is usually regarded as a transition between continuous and discrete vegetation in previous studies.Were row treated as the unit for calculating the four components in the Geometric Optical model (GO model),the formula would be too complex and difficult to retrieve.This study focuses on the microscopic structure of row crops.Regarding the row crop as a result of leaves clumped at canopy scale,we apply clumping index to link continuous vegetation and row crops.Meanwhile,the formula of clumping index is deduced theoretically.Then taking leaf as the basic unit,we calculate the four components of the GO model and develop a BRDF model for continuous vegetation,which is gradually extended to the unified BRDF model for row crops.It is of great importance to introduce clumping index into BRDF model.In order to evaluate the performance of the unified BRDF model,the canopy BRDF data collected in field experiment,"Watershed Allied Telemetry Experiment Research (WATER)",from May 30th to July 1st,2008 are used as the validation dataset for the simulated values.The results show that the unified model proposed in this paper is able to accurately describe the non-isotropic characteristics of canopy reflectance for row crops.In addition,the model is simple and easy to retrieve.In general,there is no irreconcilable conflict between continuous and discrete vegetation,so understanding their common and individual characteristics is advantageous for simulating canopy BRDF.It is proven that the four components of the GO model is the basic motivational factor for bidirectional reflectance of all vegetation types.展开更多
文摘该文构建了光子在作物冠层传输的随机过程,采用蒙特卡罗(M on te C arlo)方法模拟了作物冠层BRDF。对比蒙特卡罗模型和M CRM模型,分析了叶倾角(LAD)与叶面积指数(LA I)对两模型BRDF的影响,并对其中的变化给出了合理的解释。研究表明,两模型虽然在模拟的BRDF数值上有一定差异,但在不同LAD和LA I对BRDF的变化趋势上达到了较好的一致性。最后,用实测BRDF数据验证和分析蒙特卡罗模型,结果表明,蒙特卡罗模型与实测BRDF较为吻合,蒙特卡罗模型可以作为其他作物冠层BRDF前向模拟的有效验证工具。
文摘TB96 2000064137真空紫外反射率计用于BRDF的测量=Measurementof BRDF by using the VUV reflectomters[刊,中]/唐玉国,齐文宗,李福田(中科院长春光机所应用光学国家重点实验室.吉林,长春(130022))//光学技术.—1999,(3).—51-53,55介绍了一种真空紫外反射率计,采用间接测量方法,用该反射率计测试了聚四氟乙烯漫反射板的双向反射率分布函数(BRDF),正入射时该聚四氟乙烯漫反射板15°到75°的双向反射率分布函数偏差为13%。(方舟)
文摘目标双向反射分布函数BRDF (Bidirectional Reflectance Distribution Function)不仅是陆面遥感的关键地球物理参数,也是星载光学遥感仪器基于地面目标的场地辐射校正重要参量,是影响定标精度的关键要素。传统野外地物多角度测量使用的观测设备,一般其结构较为复杂,重量体积较大,而且运输和组装过程繁琐,观测目标时容易受地形和交通限制,难以进行高效快速精确的野外测量。近年来,无人机由于其设备操作简便、运输和观测方式灵活等方面的优点,可作为新的观测平台应用于当前遥感试验中。本文设计了一种基于无人机平台的地表BRDF测量装置、观测方案和数据处理流程。利用多旋翼低空无人机和云台的组合,搭载野外地物光谱仪和跟拍相机,通过对地面目标多角度观测和高精度定位及角度控制,实现针对固定目标的多方位角和天顶角观测。本文采用上述设计方案和观测流程,在敦煌辐射校正场开展多次稳定均匀沙漠目标的多角度光谱观测试验,并利用实验观测数据,基于Ross-Li核驱动模型推算了场地BRDF模型参数,并与MODIS的陆表BRDF产品(MCD43C1)及反射率产品(MOD/MYD09)进行对比验证。通过开展野外实验,核验了这种新的BRDF观测手段的可靠性,获取的敦煌地表BRDF参数与MODIS遥感产品有良好的一致性,各波段的相对偏差在5%以内。本研究表明,基于多旋翼无人机的BRDF观测系统,提供了一种全新的地物目标方向反射特性观测方法,可用于自动化高频次场地特性观测以及卫星同步定标等野外实验活动。在保证观测精度的同时,极大地减轻人力物力的投入,值得广泛推广应用。
基金supported by National Natural Science Foundation of China (Grant Nos. 91025006, 40730525, 40871186 and 40801125)Special Funds for National High Technology Research and Development Program of China (Grant Nos. 2009AA12Z143 and 2009A122103)+1 种基金Major State Basic Research Project (973) (Grant No. 2007CB714402)"Simultaneous Remote Sensing and Ground-based Experiment in Heihe River Basin and Comprehensive Platform Construction" in the Chinese Academy of Sciences’ Action-Plan for West Development (the second phase) (Grant No. KZCX2-XB2-09)
文摘Row sowing is a basic crop sowing method in China,and thus an accurate Bidirectional Reflectance Distribution Function (BRDF) model of row crops is the foundation for describing the canopy bidirectional reflectance characteristics and estimating crop ecological parameters.Because of the macroscopically geometric difference,the row crop is usually regarded as a transition between continuous and discrete vegetation in previous studies.Were row treated as the unit for calculating the four components in the Geometric Optical model (GO model),the formula would be too complex and difficult to retrieve.This study focuses on the microscopic structure of row crops.Regarding the row crop as a result of leaves clumped at canopy scale,we apply clumping index to link continuous vegetation and row crops.Meanwhile,the formula of clumping index is deduced theoretically.Then taking leaf as the basic unit,we calculate the four components of the GO model and develop a BRDF model for continuous vegetation,which is gradually extended to the unified BRDF model for row crops.It is of great importance to introduce clumping index into BRDF model.In order to evaluate the performance of the unified BRDF model,the canopy BRDF data collected in field experiment,"Watershed Allied Telemetry Experiment Research (WATER)",from May 30th to July 1st,2008 are used as the validation dataset for the simulated values.The results show that the unified model proposed in this paper is able to accurately describe the non-isotropic characteristics of canopy reflectance for row crops.In addition,the model is simple and easy to retrieve.In general,there is no irreconcilable conflict between continuous and discrete vegetation,so understanding their common and individual characteristics is advantageous for simulating canopy BRDF.It is proven that the four components of the GO model is the basic motivational factor for bidirectional reflectance of all vegetation types.
