Shape from Positional-Contrast: Characterising Sketches with Qualitative Line Arrangements

Graphical queries for the purpose of searching for pictorial information are of growinginterestinareaswherepicturesprovidevaluableinformation, including, for instance, design, architecture, and engineering. Sketching graphical queries is a natural way of revealing the visual appearance of objects one has in mind. The problem which arises is identifying necessary shape properties of sketches, thatis,thosepropertieswhicharenotaccidentalbutarenecessaryforspecifying a particular object property...