Arc Segmentation in Engineering Drawings

This paper describes a method for the recognition of outlines in engineering drawing in terms of line and arc primitives. The approach is based on vectorizing a binary image, smoothing the vectors so a sequence of small straight lines, and then attempting to fit arcs. Two further levels of constraints are then applied. One ensure smoothness where appropriate, which results in vectors that are pleasing to the eye, and suitable for some manufacturing processes. The next optional stage applies rules and sometimes results in perfectly correct views, but can fail, and can introduce distortion in unusual cases. Complex drawings are not successfully processed at present due to limitation in the extraction of vector sequences at branch points. This is not a major limitation and is expected to be resolved by current research, and in time for the GREC-2001 conference.