  The segregation of image parts into foreground and background is an important
aspect of the neural computation of 3D scene perception. To achieve such
segregation, the brain needs information about border ownership; that is, the
belongingness of a contour to a specific surface represented in the image. This
article presents psychophysical data derived from 3D percepts of figure and
ground that were generated by presenting 2D images composed of spatially
disjoint shapes that pointed inward or outward relative to the continuous
boundaries that they induced along their collinear edges. The shapes in some
images had the same contrast (black or white) with respect to the background
gray. Other images included opposite contrasts along each induced continuous
boundary. Psychophysical results show that figure vs ground judgment
probabilities in response to these ambiguous displays are determined by the
orientation of contrasts only, not by their relative contrasts, despite the
fact that many border ownership cells in cortical area V2 respond to a
preferred relative contrast. The FACADE and 3D LAMINART models are used to
explain these data.
