Application of Spectral Unmixing on Hyperspectral Data of the Historic Volcanic Products of Mt. Etna (Italy)
Application of Spectral Unmixing on Hyperspectral Data of the Historic Volcanic Products of Mt. Etna (Italy)
复制标题
光谱分解在埃特纳火山（意大利）历史火山产物高光谱数据中的应用
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发表时间：
2018
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通讯作者：
A. Rontogiannis
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作者：
V. Daskalopoulou;O. Sykioti;Catherine Karagiannopoulou;K. Koutroumbas;A. Rontogiannis
在这项研究中，我们专注于识别的各种火山产品的山。埃特纳（意大利西西里东部）。山埃特纳是最活跃的玄武质复合成层火山之一，具有迅速、剧烈、持续地改变其陆场的能力。为此目的，美国航天局EO-1/EOS高光谱数据（HSI）被用于区分熔岩流，并在历史上的“1536”至“1669”时代的Torre del Filosofo形成的映射。选择这些火山产物是因为a）它们独特的空间分布，B）光谱相似性和c）与周围较年轻熔岩的场分离。由于其组成的高变异性，相应的HSI像素混合，因此该问题是解决光谱解混（SU）技术。首先，端元提取，对于每种熔岩类型，通过平均超过高斯分布的像素反射率的相关区域的兴趣（ROI）。然后，通过两种解混模型估计丰度：约束线性最小二乘解混（LLSU）和双线性解混（BLU），应用于光谱特征和它们的变换版本，即通过傅立叶变换（FT）在频域中。历史熔岩流描绘结果，提出创建丰度图的方法。此外，使用埃特纳地质图进行定性评价，而定量评估是通过推导的结构相似性指数（SSIM）的每一个实施的方法。最后，我们解决的程度熔岩流的可分离性与相互比较的所有方法，并给出一个估计的计算最有效的方法。具体研究表明，HSI为火山岩流的分异和成图提供了有用的信息。埃特纳，尽管限制，如相对粗糙的像素大小，嘈杂的频带和稀疏数量的参考书目熔岩光谱测量。
In this study, we focus on the identification of various volcanic products of Mt. Etna (eastern Sicily, Italy). Mt. Etna is one of the most active basaltic composite stratovolcanoes with the ability to change its land field rapidly, vigorously and continuously. For this purpose, NASA EO-1/Hyperion hyperspectral data (HSI) are used for lava flow differentiation and mapping within the historic “1536” to “1669” era of the Torre del Filosofo formation. These volcanic products are selected, due to a) their distinct spatial distribution, b) spectral similarity and c) field segregation from surrounding younger lavas. Due to their high compositional variability, the corresponding HSI pixels are mixed thus the problem is tackled with Spectral Unmixing (SU) techniques. First, endmember extraction, for each lava type, is performed by averaging over a Gaussian distribution of pixel reflectances of its associated region of interest (ROI). Then, abundances are estimated by two unmixing models: Constraint Linear Least Squares Unmixing (LLSU) and Bilinear Unmixing (BLU), applied on both spectral signatures and transformed versions of them, i.e. in the frequency domain through a Fourier Transform (FT). Historic lava flow delineation results are presented creating abundance maps per method. Also, a qualitative evaluation is performed using the Etna geological map, while a quantitative assessment is performed through derivation of the Structural Similarity Index (SSIM) of each implemented method. Ultimately, we address the degree of lava flow separability with the intercomparison of all methods and give an estimation of the computationally most efficient method. The specific research shows that HSIs provide useful information for individual lava flow differentiation and mapping in a complex environment such as Mt. Etna, despite limitations such as the relatively coarse pixel size, noisy bands and the sparse number of bibliographic references on lava spectral measurements.