%0 Journal Article
%T Field of View Effect on the Remote Sensing Field Radiometric Measurements<br>遥感地面辐射观测中的视场效应问题研究
%A LI Li
%A QIAO Yan-li
%A GU Xing-f
%A YU Tao
%A <br>李丽
%A 乔延利
%A 顾行发
%A 余涛
%J 遥感学报
%D 2006
%I 
%X Satellite observations use very narrow field of view(FOV) ( less than 0·01°) but the field measurements use generally very wideFOV(often between 10°and 40°) in order to obtain representative sampling size. This difference may introduce some large errors. The objective of this paper is to propose a practicalmodelingmethod and evaluate field ofview effecton the field reflectancemeasurements for row crops. Themodel considers a row crop as a repetition of rectangularwalls and then translates to a grid mi age with sufficient spatial resolution. The wideFOVreflectance is determined by averaging the reflectance of the elements. Thismodelhas been used for studying a typical row structure crop (maize canopy) for observation angles (from -60°to +60°with step of5°) and for threeFOV(10°, 25°, 45°). The results show thatwide FOVmeasurements generally underestmi ate the reflectance in the red domain (up to -25% of relative reflectancewhen a 25°ofFOV) and have overestmi ation in the near infrared domain (up to 10% of relative reflectancewhen a 25°ofFOV). For different viewing angles, the vegetation contribution is overestmi ated in the illumination direction and underestmi ated in the opposite direction; in the thermal infrared domain, the brightness temperature is generally underestmi ated for viewing angle less than 20°. This study can be used not only to analyze thatFOVeffects, but also tomake optmi al design of observation geometry(FOV, measurement height, measurement spatial size etc. ) for minmi izing the measurement errors, and/or to introduce some corrections to reduce theFOVeffects.
%K reflectance measurement
%K directional brightness temperature
%K FOV effects
%K grid modelling<br>视场效应
%K 网格模型
%K 反射率测量
%K 方向亮温
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=A41A70F4AB56AB1B&jid=F926358B31AC94511E4382C083F7683C&aid=3199B239E86F2DA2&yid=37904DC365DD7266&vid=F3090AE9B60B7ED1&iid=94C357A881DFC066&sid=5AE7FA263C8A6D65&eid=6D25DD85174CF6DB&journal_id=1007-4619&journal_name=遥感学报&referenced_num=0&reference_num=5