An Algorithm for the Extraction of Determinant Contour Points of Lines in Scanned Drawings
扫描图象曲线轮廊关键点的提取及其处理

The conversion of drawing image into vector form is of important in many fields, especially in the field of electronic and mechanical applications. In this paper, a new approach for extracting determinant contour points of lines in scanned engineering drawings is proposed. This method can not only obtain determinant contour points placed in line contour of the drawing image but also process these points automatically. The basic idea of proposed algorithm is totally different from that of traditional algorithms, it can remedy some deficiencies which are suffered from traditional algorithms and executes successfully without thinning. This algorithm detects black runs on scanning or consecutive scanning lines automatically, and then extracts determinant contour points from scanned engineering drawings, the main idea of the detecting algorithm is that:first,black runs on current scanning line are detected automatically, and determinant contour points are extracted by detecting the edge points of both current black run and the next black run which is on consecutive scanning line if the relevant condition holds. Second,based on the determinant contour points,the extraction of lines from the original drawing image will be done easily by using B spline theory. Experimantal results indicate that the algorithm has higher speed and other advantages.