High spatial resolution spectral mixture analysis of urban reflectance
High spatial resolution spectral mixture analysis of urban reflectance
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DOI：
10.1016/j.rse.2003.04.008
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发表时间：
2003-11
影响因子：
13.5
通讯作者：
C. Small
中科院分区：
文献类型：
--
作者：
C. Small
本研究利用IKONOS卫星影像来量化全球14个城市地区的城市反射率的空间和光谱特征。IKONOS 1-m全色图像提供了一个详细的测量空间变化的光谱，而IKONOS 4-m多光谱图像允许不同的材料的相对贡献的光谱异质辐射场被确定和其丰度被映射。空间自相关分析表明，城市反射率的特征尺度一致的10和20米的城市在这项研究中。光谱混合分析量化的相对贡献占主导地位的光谱端元的整体反射率的城市马赛克。由两个低阶主成分定义的光谱混合空间占图像方差的96%至99%，并且具有由高分辨率、低分辨率和植被端元跨越的一致的三角形结构。这些端元之间的光谱混合主要是线性的，虽然观察到一些非线性混合沿着灰轴跨越高和低的非线性端元。反演的约束三组分线性混合模型产生稳定的，一致的端元丰度估计。RMS误差的基础上观测到的辐射率矢量和建模的辐射率矢量（来自分数估计和图像端元）之间的失配一般小于3%的平均观测到的辐射率。观测到的辐射率和分数估计之间的协议并不能保证面积分数估计的准确性，但它确实表明，三分量线性模型提供了一致的和广泛适用的物理特性的城市反射率。实地验证的分数估计在城市植被监测和透水表面制图中有应用。
This study uses IKONOS imagery to quantify the combined spatial and spectral characteristics of urban reflectance in 14 urban areas worldwide. IKONOS 1-m panchromatic imagery provides a detailed measure of spatial variations in albedo while IKONOS 4-m multispectral imagery allows the relative contributions of different materials to the spectrally heterogeneous radiance field to be determined and their abundance to be mapped. Spatial autocorrelation analyses indicate that the characteristic scale of urban reflectance is consistently between 10 and 20 m for the cities in this study. Spectral mixture analysis quantifies the relative contributions of the dominant spectral endmembers to the overall reflectance of the urban mosaic. Spectral mixing spaces defined by the two low-order principal components account for 96% to 99% of image variance and have a consistent triangular structure spanned by high albedo, low albedo and vegetation endmembers. Spectral mixing among these endmembers is predominantly linear although some nonlinear mixing is observed along the gray axis spanning the high and low albedo endmembers. Inversion of a constrained three-component linear mixing model produces stable, consistent estimates of endmember abundance. RMS errors based on the misfit between observed radiance vectors and modeled radiance vectors (derived from fraction estimates and image endmembers) are generally less than 3% of the mean of the observed radiance. Agreement between observed radiance and fraction estimates does not guarantee the accuracy of the areal fraction estimates, but it does indicate that the three-component linear model provides a consistent and widely applicable physical characterization of urban reflectance. Field validated fraction estimates have applications in urban vegetation monitoring and pervious surface mapping.