Simplification and vectorization of sketched drawings

Abstract

The need to process and extract information from drawings stems from practitioners in the fields of engineering, architectural design, and cartography among others, with the need to process paper-based drawings. These drawings need to be digitized as raster images from which all line strokes are then extracted. All processing of the drawing is carried out after drawing completion, hence the term offline processing. Although the widespread availability of digital tablets saw a shift towards digital-born drawings, offline processing of drawings remains relevant since the paper medium remains in use by artists and designers. Moreover, digital-born drawings may be saved in either raster format or as time-stamped vectors. Digital-born drawings saved as raster images require the same processing as their paper-based counterparts. Thus, the difference between online and offline sketch processing lies not in the medium used, but in the stroke information available which then affects the possible methods of interpretation. In offline sketching applications, the user must complete the drawing before this is interpreted as a whole in a mostly noninteractive manner. This chapter will focus on techniques required for offline sketch processing and simplification. [extract].