高斯混合模型自动阈值法遥感冰川信息提取

利用阈值法进行遥感地物提取效率高、准确率高，但是在阈值的选取方面，传统的手动选取阈值，自动化低，需反复试操作，且易受主观因素影响。文中通过期望最大算法对局部冰川区域归一化雪覆盖指数建立高斯混合模型，去除区域内的混合像元类，再利用高斯混合模型模拟纯净化后的冰川类、非冰川类的NDSI分布情况，根据改进后的高斯混合模型分布情况，自动计算出区域内的冰川提取阈值。本文对不同海拔的3个区域进行算法实验，然后将新疆哈密的哈尔里克山冰川提取边界与冰川编目数据进行对比验证。研究结果表明，该方法自动计算的冰川提取阈值结果可靠、精度高，在差异较大区域仍较稳定，有一定的应用价值。

Extracting glacier information from remote sensing imageries by automatic threshold method of Gaussian mixture model

Extraction of glacier by remote sensing has important value of scientific research and application. The threshold segmentation method has high efficiency and accuracy in remote sensing feature extraction. However, in terms of threshold selection, traditional manual threshold selection demonstrate low automation, repeated trial operation, and is easily affected by subjective factors. For example, the normalized snow cover index can separate the glacier information from the background information effectively. However, the threshold is almost always found manually, and hence is easily affected by subjective factors. Therefore, developing an effective method is necessary to calculate the glacier extraction threshold automatically.Gaussian Mixture Model (GMM) is established for the Normalized Difference Snow Index (NDSI) of the local glacier region by the expected maximum algorithm and to remove the mixed pixel meta classes in the region. Then, the GMM was used to simulate the NDSI distribution of purified glacier and non-glacier. According to the distribution of the improved Gaussian mixture model, the glacier extraction threshold in the region was calculated automatically.Three regions at different altitudes were experimented. Subsequently, the boundary extraction of Karlik mountain glacier in Hami, Xinjiang was compared with the glacier inventory data, and good extraction results were obtained. The experimental results show that the threshold values calculated by different grids in the same experimental area are slightly different, whereas the threshold values calculated by different grids in various experimental areas are largely different, thereby also indicating that the algorithm is still stable in the regions with large differences. As such, the results of glacier extraction threshold calculated by using this method are reliable, accurate, and stable in different regions.Result also shows that this method solves the problem of the unbalanced proportion of glacier and non-glacier in GMM curve simulation to some extent, and the automatic calculation results of glacier extraction threshold are reliable, accurate, and stable in regions with large differences. This GMM method is available for certain applications of delineating glacier boundary in remote sensing.