Summary: Spatial Vision, Vol. 15, No. 1, pp. 4559 (2001)
Ó VSP 2001.
Occlusion junctions do not improve stereoacuity
RAYMOND VAN EE 1;2;¤
, BARTON L. ANDERSON1 and HANY FARID 1
1 Department of Brain and Cognitive Sciences, Massachussetts Institute of Technology, USA
2 Utrecht University, Helmholtz Institute, Princeton Plein 5, 3584 CC, Utrecht, The Netherlands
Received 20 September 2000; revised 24 December 2000; accepted 1 January 2001
Abstract--Occlusion geometry gives rise to interocular shifts in the positions of binocularly viewed
contour junctions. Since these shifts do not give rise to normal binocular disparities, they have
been called `pseudodisparities'. Previous work has shown that the unmatched contour segments
of a partially occluded contour at occlusion junctions can be used to recover the geometry of the
occluding surface through the construction of `illusory' contours. Here, experiments were performed
to determinewhether such junctionshiftscould enhance stereoscopicdepth detectionwhen the relative
disparity between the contours was below threshold. Our results showed that stereoscopic depth
detection does not improve when pseudodisparity is present. We conclude that the visual system
is less sensitive to pseudodisparity than to conventional disparity information. We suggest that the
primary role of pseudodisparityis to overcome conditions of camou age.
Keywords: Binocular vision; stereopsis; stereoacuity; occlusion.