扫描数字化地形图纠正拼接系统的高效系统设计

A High-Efficiency System for Topographic Map's Correction and Patching

地形图扫描数字化的前期工作需要解决两个重点问题,即纠正和拼接。传统方法是利用图像处理软件逐个选取并输入控制点,然后进行纠正。该方法是一种具有普遍适用性的图像纠正方法,但需要一个个地输入控制点坐标,操作起来繁琐费时。在实验室环境下,没有大型扫描仪,纠正完成的地形图尚需要进行拼接。在分析扫描地形图变形特点的基础上,提出了变形进行纠正的经验公式,并用VC++开发了一个针对地形图的纠正和拼接的专用软件。其最大的优点是图块纠正时不需要逐点输入控制点坐标,拼接时方便快捷。最后分别用了绝对检验方法和相对检验方法对公里网格点和网格点内部坐标进行检验,表明其误差不超过0.3%。

Two key problems are solved in the first period of digitalizing the scanned Topographic Map. Traditional method, using image processing software, follows such steps: firstly select the reference point one by one and input their coordinates, secondly correct the whole map. This method is applicable to all kinds of images, but is not a special one for Topographic Map. And in the lab where super scanners are usually not available, another step is needed after correction and that is to patch together the topographic maps. In this paper, based on the analyses of the distortion characteristic of scanned topographic map, an experienced formula is put forward, and a special topographic map's correction and patching software is developed with visual C++. The advantage of this software is that when correcting the images, there is no need to input the reference points' coordinates one by one any more, and indeed it offers a convenient and quick method to patch the images. Both absolute and relative examinations show that the range of error is less than 0.3%.