p373fig11.03 Both contrast-specific binocular fusion and contrast-invariant boundary perception are needed to properly see the world in depth.<BR>||  How to unify contrast-specific binocular fusion with contrast-invariant boundary perception?  Contrast-specific binocular fusion: [Left, right] eye view [, no] binocular fusion.  Contrast-invariant boundary perception: contrast polarity along the gray square edge reverses; opposite polarities are pooled to form object boundary.