A High Speed Raster-to-Vector Conversion Using Special Hardware for Contour Tracking

image memory access, such as an access to a region This paper describes a high speed raster-to-vector conversion technique which is applicable to many fields in drawing processing. The major feature of the proposed technique is that raster-to-vector conversion can be realized by one simple raster scanning process to an input image and by processings performed only with contour tracking due to the fact that a significant part of a drawing image is only the boundary between black and white regions. In order to speed up raster-to-vector conversion, the raster scanning process and processings with contour tracking, which consume much time but are repetitions of simple processings, have been implemented by a special hardware. Reduction of about 90% in raster-to-vector conversion time is possible by using the accelerator. The effectiveness and flexibility of the proposed processings are discussed, showing experimental results of automatic extraction of polygons which represent houses from map images.