卫星TM影像阴影消除方法的探讨

地形决定了地面电磁波反射的强弱 ,反射的强弱又决定了被动遥感影像的质量。卫星影像的阴影与地形密切相关 ,山势越陡峭 ,影像阴影越多。云南省菜阳河保护区山高坡陡 ,TM卫星影像的阴影也相对增加 ,占 10 %以上。这给判读带来了很大的不便。本文利用阴阳坡归一化探讨了地形阴影消除的方法 ,并在菜阳河保护区及其它保护区影像阴影消除中取得了很好的效果。

夏热冬暖地区居住小区的阴影率

分析了夏热冬暖地区建筑利用日照阴影防热降温的处理手法 ,论述了日照阴影与居住小区热环境的密切关系 ,并通过对同一居住小区两个不同的规划方案的日照阴影情况进行对比研究 ,由此提出阴影率的概念 。

数学形态学辅助下基于光谱指数的作物冠层组分分类

近地遥感常被用于获取作物冠层组分信息,但在提取叶片反射率时常受到土壤背景、穗和阴影效应的影响。为准确分类并提取作物冠层组分信息,该研究通过分析小麦冠层各组分(光照/阴影叶片、土壤、穗)的光谱及纹理差异,提出了一种光谱指数与数学形态学结合的作物冠层组分分类方法,探讨不同生育时期的最佳冠层组分分类方法,并定量分析不同组分的归一化光谱指数与小麦叶片氮含量的关系。结果表明:光谱指数法能较好地区分小麦抽穗前的不同冠层组分,而抽穗期的分类效果易受麦穗影响;光谱指数与数学形态学结合的分类方法能较好地消除麦穗对光照/阴影叶片提取的干扰(总体分类精度为97.80%,Kappa系数为0.97,运行时间3.87 min),该方法的分类精度及运行效率均优于传统分类方法(迭代自组织数据分析算法(Iterative Selforganizing Data Analysis Techniques Algorithm, ISODATA)和最大似然估计(Maximum Likelihood Estimation, MLE));而且,基于光照和阴影叶片的归一化光谱指数对叶片氮含量最敏感。研究结果可为其他作物冠层组分分类和精准农业中农学参数的定量反演提供技术参考。

The potential information in the temperature difference between shadow and sunlit of surfaces and a new way of retrieving the soil moisture

The thermal inertia and plant water stress index are oftenadopted to estimate soil moisture available for crops or plants. However, it is not very easy to obtain two temporal temperatures for thermal inertia model and air temperature for the plant water stress mode. Shadows of ground objects are often referred to noise on visible and near infrared remote sensing. But the difference of temperature between shadows and sunlit contains rich information concerning with heat-water status for soil. This paper presented a new way to excavate just by temperature difference usually between shadow and sunlit surface. Experiments validated the ideal. We can adopt thermal camera to measure the differences in the field measurements. However, we must use inversion based on multianglar thermal infrared remote sensing data in airborne and spaceborne. An inverting model was also presented by using Monte-Carlo and the least square method. Results show that this way is feasible.