LINE FITTING METHOD FOR LIEN DRAWINGS BASED ON CONTOURS AND SKELETONS

This paper presents a new line extraction method to capture vectors ba sed on contours and skeletons from line drawing raster images in which the lines are touched by characters or other lines. Conventionally, t wo line extraction methods have generally been used. One is a thinning method. The other is a medial line extraction method based on paralle l pairs of contours. The thinning method tends to distort the extracte d lines, especially at intersections and corners. On the other hand, t he medial line extraction method has a poor capability as regards capt uring correct lines at intersections. Contours are able to maintain ed ge shapes well, while skeletons preserve topological features; thus, a combination of these features effectively leads to the best fitting l ine. In the proposed method, the line which best fits the original ima ge is selected from among various candidate lines. The candidates are created from several merged short skeleton fragments located between p airs of short contour fragments. The method is also extended to circul ar arc fitting. Experimental results show that the proposed line fitti ng method is effective.