CCD扫描等高线图的自动栅格—矢量转换方法

AUTOMATIC RASTER-VECTOR CONVERTINGFROM CCD-SCANNED TOPOGRAPHIC MAP

本文利用数学形态学（Mathematical Morphology）的理论对CCD扫描等高线图的自动栅格矢量化方法进行了较深入的探讨。文中首先对灰度级和二值等高线影像的各种处理与自动编辑方法进行了详细的讨论，并提出了一种用形态变换自动确定地貌变化特征点的方法。利用这些求得的地貌特征点将复杂地形划分成若干坡向单调变化的坡段，从而导出一种简便而快速的等高线自动矢量化与高程推算的方法。

For the purpose of autolnatically generating Digital Terrain Models (DTMs). this paper shows how mathematical morphology can be used for automatic raster--vector converting from CCD--scanned topographic contour map. Firstly. both gray--velue and binary contour image pre--processes such as smoothings. thresholdings, thinnings, and gap connectings are brifely discussed by using the algorithms of edge--presserving smoo- things and morphology transformations. In order to determine the elevations of contours. a method for automaticlly finding critical geomorphological points (summits. sinks. and saddles) is presented based on shap transformations. According to the critical geomor- phological points and in order to get vector data. an efficient.method for line follow- ing and elevation determining s given. Finally. the example is given step by step to demonstrate the efficiency of the suggested approach