利用DEM边缘检测进行黄土地貌沟沿线自动提取

An Edge Detection Based Method for Extraction of Loess Shoulder-Line from Grid DEM

在分析黄土地貌沟沿线形态特征的基础上,提出了基于规则格网DEM,通过引入边缘检测算子提取并连接沟沿线候选点,并借助形态学方法滤除细碎线段,最终生成沟沿线的方法。黄土丘陵沟壑区的实验结果显示,Sobel、Roberts、Prewitt梯度算子检测得到的沟沿线封闭性较差,线段较零碎,与实际沟沿线不符,不适用于沟沿线的自动提取;而LOG算子提取的线段连续、精度高,是理想的沟沿线检测算子,能够实现黄土地貌沟沿线较准确、有效的自动提取。

We propose a new method for extracting loess shoulder-lines from grid DEM.The morphological characteristics of loess shoulder-lines are investigated firstly.By applying the edge detection approach,a new method for extracting loess shoulder-line candidate points is proposed based on the prominent height variation of the points.The algorithm then connects the candidate points to small line segments by morphological methods.Finally,precise,systematic loess shoulder-lines are extracted after refining the line segments.Experiments in the loess hill area show that the extracted lines from gradient based operators,such as Sobel,Roberts and Prewitt,have relatively poor results on both integration and matching precision with manually extracted loess shoulder-lines,while loess shoulder-lines extracted by LOG operator has very good matching ratio to the manually extracted loess shoulder-lines.So LOG is an ideal loess shoulder-lines extraction operator and can be used to extract loess shoulder-lines effectively and automatically.