基于无人机DEM的灌区渠系提取方法

大范围灌区渠系的制图对于现代节水灌溉技术以及合理配水、安全输水具有重要意义。但目前所获得的灌区遥感影像分辨率不高,渠系提取较难。本文以无人机航空摄影测量获得的数字高程模型(DEM)为基础,根据渠系特征,使用灌区坡度数据,采用改进的霍夫变换方法,实现了对灌区渠系网络的提取。与面向对象、监督分类方法和手绘结果进行对比,该方法提取的渠系连续、提取完整度可达85.61%。误差主要集中在无衬渠系中土壤沉积较多(坡度变化不明显)的位置以及相交渠系处理时保留渠堤位置而造成。该方法根据灌区地形特征,基于高精度高程数据进行渠系提取,是数字地形分析结合图像处理在精细农业中的一次有益探索。

Extraction Method of Irrigation Networks in Irrigated Area Based on UAV DEM

Mapping of irrigation networks in large-scale irrigation districts is very important for the development of modern water-saving irrigation technology, at the same time, it is also important for allocating water reasonably and supplying water safely. However, due to the low resolution of the remote sensing images currently, it is very difficult to extract the irrigation networks in detail. Based on the slope data generated from digital elevation model (DEM) which was obtained from the unmanned aerial vehicle (UAV) aerial photogrammetry collected in March, 2016, and combined the characteristics of irrigation networks, a revised hough transform (RHT) method was adopted, which realized the fast extraction of irrigation networks. Compared with the object-oriented method, supervised-classification method and the field measurement results, the integrity of RHT method can reach about 85.61%. Errors were mainly concentrated in the non liner cannal part, which existed more sediment deposition (slope was not obvious), and also in the cannal dike when unneceassary parallel or crossed cannal were eliminated. According to the characteristics of irrigation networks, the research result was a beneficial exploration for the study of artificial irrigation network system, which was based on the high-resolution DEMs.