Recognition of 3D Objects in 3D Scenes
Abstract
J. J. Gibson proposed that we use the positions at which objects contact
the ground in a 2D projection--optical contact--to perceive the layout of
objects in 3D scenes. We considered this proposal in four series of
experiments that used either computer-generated scenes, movies of real
scenes into which computer-generated objects were inserted, or real scenes
viewed directly. One series of experiments compared the effectiveness of
optical contact with the ground to that of optical contact with other
surfaces in determining layout. The other three series of experiments
examined interactions of optical contact with motion parallax, occlusion
and shadow. Optical contact with the ground was an effective source of
information for layout, dominating optical contact with other
surfaces. Optical contact was more effective than motion parallax for
scenes with one or two objects, but not for scenes with three rigidly
moving objects. A shadow on the ground was more effective than a second
object on the ground in determining the perceived location of a floating
object. These results support Gibson's emphasis on the importance of the
ground surface in the perception of the visual world.