Company, PedroVarley, Peter A. C.Plumed, RaquelAndrea Giachetti and Paolo Pingi and Filippo Stanco2017-09-112017-09-112017978-3-03868-048-2https://doi.org/10.2312/stag.20171223https://diglib.eg.org:443/handle/10.2312/stag20171223This paper describes a new "envelope" approach for detecting object perimeters in line-drawings vectorised from sketches of polyhedral objects. Existing approaches for extracting contours from digital images are unsuitable for Sketch-Based Modelling, as they calculate where the contour is, but not which elements of the line-drawing belong to it. In our approach, the perimeter is described in terms of lines and junctions (including intersections and T-junctions) of the original line drawing.I.3.5 [Computer Graphics]Computational Geometry and Object ModelingGeometric algorithmslanguagesand systemsI.4.6 [Image Processing and Computer Vision]SegmentationEdge and feature detection10.2312/stag.2017122323-29