中文摘要：

基于热红外成像仪获取的玉米冠层图像，对垄行结构玉米的方向亮温（DBT）进行模型化描述并开展了初步验证工作。模型中假设某一方向上的冠层DBT是组分亮温及各组分在视场中所占面积权重的函数，它们在视场中的比例依赖太阳与传感器的几何位置关系，以及在作物行内，作物行与行之间孔隙的分布。对于玉米冠层的几何特征，简化为横截面是矩形的、其中有空隙透光的一组无限长的平行立方体；立方体内双向孔隙率的方向变化由Kuusk函数来描述。模型模拟表明，玉米亮温组分在视场中的权重具有垄行特性。中午前后，通过对中等密度的冠层DBT模拟，在DBT极坐标图形上发现了一个明显位于垄行方向的热条带的出现，热点出现在太阳位置的周围。最后，利用实地观测的结果与模型模拟结果作对比，对该模型的不足和以后的改进作了初步分析。

英文摘要：

A modeling study on the variations of directional brightness temperature（DBT） for row-structure crops was carried out with the help of the images captured by a large aperture thermal infrared camera over a maize canopy. The model assumes that the DBT is a function of component brightness temperatures and their directional fractions. Component fractions in the scene of view depend on sun-view geometry and the distributions of gaps within and between plant rows. To describe canopy geometrical features, a system of porous hedgerows with rectangle cross-section has been used; the directional variations of gap fraction are described by Kuusk function. The model demonstrates directional variations of DBT as a function of sun-viewing geometry and canopy geometrical structure as well as component brightness temperatures. In the simulation of DBT over a middle dense canopy near the noontime, the results reveal an evident row-direction-oriented hot stripe in DBT polar map, where appeared the hot spot along the sun direction. Further validation analysis has also been conducted which demonstrates modeled DBT agreeing closely with field observations.