Freehand Sketching Interfaces: Early Processing for Sketch Recognition
Freehand sketching interfaces allow the user to directly interact with tasks without worrying about low-level commands. The paper presents a method for interpreting on-line freehand sketch and describes a human-computer interface prototype system of freehand sketch recognition (FSR) that is designed to infer designers’ intention and interprets the input sketch into more exact 2D geometric primitives: straight lines, polylines, circles, circular arcs, ellipses, elliptical arcs, hyperbolas and parabolas. According to whether the stroke needs to be segmented or not, it is divided into single primitives and composite primitives correspondingly. Based on open/closed characteristic and semi-invariant, conic type and category of freehand sketch were defined for subdividing conic curve. Recognition approach for composite-primitive consists of three stages. The effectiveness of the algorithm is demonstrated preliminarily by experiments.
KeywordsFreehand sketching interface Recognition Segmentation Stroke
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