分析光谱角制图方法缺陷的基础上, 提出权重光谱角制图（weight spectral angle mapper, WSAM）方法。 其基本思路为: 在相似波谱曲线差异较大的特征区间设置权重, 以增大它们相似度之间的差异。 当识别某种矿物时, 可找到参考波谱与其相似性矿物波谱差异较大的特征区间, 并在此区间设置权重, 从而使相似性矿物波谱与参考波谱的相似度降低, 增加其与目标矿物的区分度。 通过AVIRIS高光谱数据的实验证明, 权重光谱角制图方法通过设置目标矿物和其相似性矿物的差异特征区间, 降低了相似矿物波谱与目标矿物标准波谱的相似性, 增加了相似性矿物的目视区分能力, 能够较为准确地区分出目标矿物和其相似性矿物。

On the basis of analyzing the deficiency of spectral angle mapper (SAM), an improved similarity measure called weight SAM (WSAM) is proposed in the present paper. The fundamental idea is to set a weight in the “difference range” to increase the discriminability between the similar minerals. When we distinguish some kind of mineral, the authors can find the “difference range”, in which the difference in spectral feature between the similar mineral spectrum and the reference spectrum is huge, and gives weight k to the spectrum in this range to reduce the similarity and increase the discriminability between similar minerals. The experiment results of spectra and AVIRIS data indicate that the WSAM method reduces the similarity of target mineral and its similar mineral and increases our ability of visual interpretation.