Pub. date: 2010 | Online Pub. Date: December 16, 2009 | DOI: 10.4135/9781412972000 | Print ISBN: 9781412940818 | Online ISBN: 9781412972000| Publisher:SAGE Publications, Inc.About this encyclopedia
Visual Filling in and Completion
P. De Weerd
Object perception crucially depends on accurate perception of object boundaries and surfaces . Boundary perception depends on boundary completion processes . Surface perception depends on surface filling-in processes . Why filling-in and completion are necessary and how they work are the topics of this entry. To simplify, it is assumed that surfaces and boundaries are defined only by differences in brightness. The need for boundary completion can be understood when considering the following example. If one stands under a tree and looks up while holding a pencil in front of one's eyes, the tree's branches and pencil will merge into a single complex distribution of dark and light on the retina. On the retina, the branches are “attached” to the pencil, but clearly, this is not what is perceived. Somehow the visual system “knows” that the branches of the tree continue behind the pencil in front, despite the fact that ...