Coding method for vector representation of engineering drawings

Many engineering drawings exist today that are still subject to change yet do not have the benefit of computer-aided design and drafting because of the cost and difficulties associated with placing them into automated graphics systems. This paper describes a new efficient vector coding method which extracts vector information in real time from raster data acquired by optically scanning and digitizing. The resultant representation of the engineering drawing can be displayed on a CRT terminal or on a plotter as a hard copy, can be rapidly edited or revised to reflect future changes and facilitates fast transfer of drawings over telephone lines to other locations enabling remote viewing and changing. Experimental results in terms of data compaction are presented for a variety of engineering drawings, including one of the CCITT standard test documents.