空间U统计量法在遥感蚀变信息提取中的应用研究

The Application of Spatial U-static Method to the Extraction of Alteration Anomalies

鉴于传统蚀变异常信息提取方法的局限性,试图在二维光谱特征空间(即散点图)中研究遥感蚀变信息的提取方法。在二维散点图中,两个波段灰度值的联合分布体现了各向异性的特点,聚类常呈类似椭圆形分布。对散点图中点的频数使用空间U统计量法逐个获得地物聚类的椭圆参数,将每个椭圆内的点映射到遥感图像上,经过目视解译,最终获得蚀变异常信息的空间分布。以青海省巴音山地区蚀变信息提取为例,对空间U统计量方法进行了应用,并将提取的异常区域与已获得的各种数据进行对比,发现铁化和泥化区域吻合度较高,取得了比主成分分析更好的蚀变信息提取效果。

The authors tried to extract alteration anomalies in spectral characteristic space （scatter plot） in view of the limitation of the traditional methods. The scatter plot takes on an anisotropic feature in associated distribution of RS data＇ s grey scale. The distribution is usually combined by oval clusters. Parameters of oval clusters are acquired sequentially by applying U - Statistic method in the frequency of the scatter plot. Through mapping the points inside the oval into RS image and interpreting visually, the spatial distribution of alteration anomalies is obtained eventually. In this paper, this new method was described with the instance of Bayinshan area in Qinghai province. Other data acquired were also comparatively studied, and it is found that the anomalies of ferruginization and argillation are consistent well with each other. This new method has a better performance than PCA in the study area.