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Automatic Production of Highly-Precise Digital Elevation Models from Topographic Map Images and its Application

地形图图像自动生成高精度数字高程模型及其应用

基本信息

批准号：
11680409
负责人：
WATANABE Takashi
金额：
$ 2.5万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In this project we made many improvements on the pilot system that can automatically produce a highly-precise digital elevation model (DEM) from images of topographic contour map, in order to make it more practicable. First, we applied the system to a lot of real topographic maps and examined the problems that it has. From the evaluation experiments, we found the following problems in automatic restoration of broken contours : (1) it may fail in restoration ; (2) it cannot detect contours with failed restoration ; (3) it cannot change connection of broken contours once they are connected to restore. To these problems, we could considerably decrease the occurrence of error restorations by using the rigid conditions for restoration and suppressing the generation of unreliable neighboring-contours relationship. Second, we found the problems in the traditional interpolation methods producing a DEM from contours given elevation values, and we developed a new interpolation method using monotone-function. The method has the following features : (1) it can produce a highly-precise DEM ; (2) It does not yield unnecessary vibrations that the other methods like the spline interpolation may often do ; (3) It can generate more suitable surfaces of DEM.We also examined the Grimson's method based on the regularization method, because the methods of this type have not been well investigated. Third, we did an improvement to make the system user-friendly by using graphical user interface : for example, we implemented the interactive restoration of broken contours to utilize the excellent function of human pattern recognition.

在本项目中，我们对能够从地形图等值线图像自动生成高精度数字高程模型(DEM)的试点系统进行了许多改进，以使其更加实用。首先，我们将该系统应用于许多真实的地形图，并检查了它存在的问题。从评价实验中，我们发现了断线自动恢复存在以下问题：(1)恢复可能失败；(2)无法检测恢复失败的轮廓；(3)一旦连接到恢复，就不能改变断线的连接。针对这些问题，利用严格的恢复条件和抑制不可靠邻域关系的产生，可以大大减少错误恢复的发生。其次，分析了传统的基于等高线的DEM内插方法存在的问题，提出了一种基于单调函数的DEM内插方法。该方法具有以下特点：(1)可以生成高精度的DEM；(2)它不会产生其他方法(如样条插值法)经常产生的不必要的振动；(3)它可以生成更合适的DEM曲面。我们还研究了基于正则化方法的Grimson方法，因为这类方法还没有得到很好的研究。第三，利用图形化的用户界面，对系统进行了改进，使系统更加人性化：例如，利用人体模式识别的优良功能，实现了断线的交互式恢复。