液晶与显示, 2020, 35 (9): 955, 网络出版: 2020-10-28
针对高光谱端元提取的空谱联合预处理方法
Spatial-spectral combined preprocessing method for hyperspectral endmember extraction
高光谱 解混合 端元提取 预处理 光谱纯度指数 hyperspectral unmixing endmember extraction preprocessing spectral purity index
摘要
混合像元的存在是制约高光谱遥感应用精度的主要原因, 因此必须进行高光谱解混合。端元提取作为高光谱解混合的关键, 往往易受噪声和异常点的干扰。为了提高端元提取精度, 针对高光谱端元提取提出了一种空谱联合的预处理方法。首先, 定义了新概念光谱纯度指数, 主要用于预估高光谱图像中每个像元的光谱纯度; 其次, 给出了基于光谱纯度指数的空间去冗余方法, 利用真实地物的空间分布连续性, 判断和移除高光谱图像中冗余像元, 最终形成精简的候选端元集。实验结果表明: 采用提出的预处理方法后, 对于模拟高光谱图像, 提取的端元与原始端元之间夹角平均减少了9022 3°, 候选端元数量少于原始像元数量的10%。该预处理方法不仅有效消除了噪声和异常点的干扰, 提高了端元提取精度, 且大幅降低了时间复杂度。
Abstract
The existence of mixed pixels is the main reason that restricts the application accuracy of hyperspectral remote sensing, so hyperspectral unmixing is necessary. As the key of hyperspectral unmixing, the endmember extraction is often susceptible to noise and outliers. In order to improve the accuracy of endmember extraction, a spatial-spectral combined preprocessing method for hyperspectral endmember extraction is proposed in this paper. Firstly, a new concept of spectral purity index (SPI) is defined, which is used to estimate the spectral purity of each pixel in hyperspectral image. Secondly, a spatial de-redundancy method based on SPI is provided, utilizing the continuity of spatial distribution of real objects in the image to judge and eliminate redundant pixels in hyperspectral image, and finally a fine set of candidate endmembers is formed. Experimental results show that after using the proposed preprocessing method, for the simulated hyperspectral image, the angle between the extracted endmembers and the original endmembers is reduced by 9.022 3° on average, and the number of candidate endmembers is less than 10% of the number of original pixels. The proposed preprocessing method not only eliminates the interference of noise and outliers effectively and improves the accuracy of endmember extraction, but also reduces the time complexity greatly.
吴银花, 王鹏冲, 吴慎将, 张发强. 针对高光谱端元提取的空谱联合预处理方法[J]. 液晶与显示, 2020, 35(9): 955. WU Yin-hua, WANG Peng-chong, WU Shen-jiang, ZHANG Fa-qiang. Spatial-spectral combined preprocessing method for hyperspectral endmember extraction[J]. Chinese Journal of Liquid Crystals and Displays, 2020, 35(9): 955.