Research Repository

Stereopsis from contrast envelopes

Langley, K and Fleet, DJ and Hibbard, PB (1999) 'Stereopsis from contrast envelopes.' Vision Research, 39 (14). 2313 - 2324. ISSN 0042-6989

[img]
Preview
Text
1-s2.0-S0042698998002715-main.pdf - Published Version

Download (239kB) | Preview

Abstract

We report two experiments concerning the site of the principal nonlinearity in second-order stereopsis. The first exploits the asymmetry in perceiving transparency with second-order stimuli found by Langley et al. (1998) (Proceedings of the Royal Society of London B, 265, 1837-1845) i.e. the product of a positive-valued contrast envelope and a mean-zero carrier grating can be seen transparently only when the disparities are consistent with the envelope appearing in front of the carrier. We measured the energy at the envelope frequencies that must be added in order to negate this asymmetry. We report that this amplitude can be predicted from the envelope sidebands and not from the magnitude of compressive pre-cortical nonlinearities measured by other researchers. In the second experiment, contrast threshold elevations were measured for the discrimination of envelope disparities following adaptation to sinusoidal gratings. It is reported that perception of the envelope's depth was affected most when the adapting grating was similar (in orientation and frequency) to the carrier, rather than to the contrast envelope. These results suggest that the principal nonlinearity in second-order stereopsis is cortical, occurring after orientation- and frequency-selective linear filtering.

Item Type: Article
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Divisions: Faculty of Science and Health > Psychology, Department of
Depositing User: Users 161 not found.
Date Deposited: 13 Feb 2015 21:02
Last Modified: 17 Aug 2017 17:41
URI: http://repository.essex.ac.uk/id/eprint/12554

Actions (login required)

View Item View Item