【摘要】 地物三维结构在像元尺度下的光学辐射特征并不等同于其表面材质的反射特性,这给基于图像信息的目标特征提取与识别造成困难。结合对三维几何体的外场零视距测量实验,分析了地物几何结构对像元综合反射率的影响效应。基于线性混合像元模型,尝试加入方向辐射特性、光照阴影和端元分布等修正因子进行改进。结果表明,较之于目前广泛使用的线性混合模型,改进模型对像元综合反射率的计算精度有所提高,相对误差由原先的13.08%平均减小至8.79%。鉴于三维异质结构混合像元综合辐射作用的复杂性,改进方法的完备性和模型普适性有待进一步研究和验证。更多还原

【Abstract】 The radiation response of three-dimensional structure of ground objects is different from the reflection characteristics of their surface material at the pixel scale, which makes it difficult to extract and recognize the objects′imaging features. Combined with the field experiment of the zero sight distance measurment of three-dimensional(3D) geometry, the influence of geometric structure on the composite reflectance of image pixels is analyzed. Based on the linear mixed model, some correction factors such as directional reflection characteristics, light shadow and end-member distribution are introduced into the model to improve its function. The results show that compared with the widely used linear mixed model, the accuracy of the improved model is increased to a certain extent for calculating the composite reflectance of the mixed pixel, and the relative error is reduced from 13.08% to 8.79%. In view of the complexity of the synthetic radiation effects of the 3D heterostructure mixed pixels, the completeness and universality of the improved model need to be further studied and verified.更多还原