ABSTRACT
Two regions can be defined for each edge in the visual field, one lying on each side. Typically, the edge appears to shape only one of these two regions, and figureground segregation is said to occur. Figures are regions of the visual field that appear to have a definite shape, a shape bestowed in part by their bounding contour (i.e., their edge). If figures are familiar objects, they can be identified (barring brain damage or the imposition of external noise). The region adjacent to the figure is locally shapeless near the edge it shares with the figure; this shapeless region is called the ground (short for background) because it often appears to complete amodally behind the figure. Although figure-ground segregation is a venerable topic in visual perception (cf. Rubin, 1915/1958), a number of questions about figures and grounds remain unanswered.
