Lazy dragging: effortless bounding-box drawing for touch-screen devices

Dragging a rectangular box is arguably one of the most intuitive and popular user interfaces to select a whole object. However, the conventional dragging method cannot be easily applied on touch-screen devices. This paper proposes a more convenient and lazier way of bounding-box (BB) drawing for touch-screen devices. The proposed method of BB drawing, termed Lazy Dragging, is designed to yield accurate BB results at interactive speeds. To this end, Lazy Dragging proceeds in two stages: (i) it first filters out explicit non-borders via graph-based segmentation; (ii) it then singles out the best four box sides among the remaining candidates using edge feature-based random forest. In this second stage, global and local edge-based border detection and a combined approach of these global and local schemes are utilized. This paper also proposes an optional stage to simplify and ameliorate further user refinement by providing invisible magnetic guidelines. This technique guides a user's touch to the nearest superpixel boundaries. Extensive experiments on a real-world dataset demonstrate that Lazy Dragging convincingly enhances the quality of input BBs in quasi real-time, enabling effortless object selection on small touch-screen devices.