Perspective click-and-drag area selections in pictures
Frank Nielsen · 2013
Pictures of man-made environments often exhibit many perspectively slanted planar parts like buildings, road or shop signages. In this paper, we present a novel user interface for area selections in pictures using per-spective click and drag operations. At preprocessing stage, our system first recognizes convex quads from multi-scale segmentations that it interprets as perspec-tive rectangles. It then builds a nested quad hierarchy labeled with quad-to-square homographies and inverse transformations. During the interactive session, when-ever a user selects an area by first clicking a corner and then dragging the diagonally opposite corner, the sys-tem proposes a perspective sub-rectangle matching the dragged diagonal defined according to the homographies of the selected quad of the hierarchy. We illustrate the perspective click’n’drag prototype with common image editing operations. 1