A scan-line algorithm for clustering line segments

Transformation of hardcopy ship drawings to electronic ones is usually accomplished through scanning and raster-to-vector conversions. Such conversions are, however, limited to produce low-degree vector entities, such as line segments, poly-lines and circular arcs. As a consequence, free-form curves, appearing in the original hardcopy, are usually disintegrated to a significant number of overlapping line and/or arc segments. The algorithm presented in this paper, consists of a scan-line processing of line segments that are grouped (clustered) with the aid of a moving scan-line and an appropriately defined distance to previously grouped entities. The performance of the algorithm is illustrated for the body-plan of a bulk carrier.