In:
Visual Neuroscience, Cambridge University Press (CUP), Vol. 21, No. 3 ( 2004-05), p. 377-382
Abstract:
The goal of this work was to study interactions of chromaticity and
luminance in edge identification. Two horizontal spatial sawtooth patterns, one with positive and the other with negative harmonics, were
compared in a two-alternative forced-choice (2-AFC) procedure. The observer identified which pattern had sharp upper or lower edges. The
fundamental frequency was 2 cycles/deg (cpd), with 5 cycles presented in a 2.5-deg square field. The pattern was presented as a 1-s
raised temporal cosine, replacing part of an 8-deg background. Stimuli were specified in a cone troland ( l , s , Y)
chromaticity space, with correction for individual equiluminance at a nominal 115 td, and individual tritan direction. A preliminary set of
interleaved staircases established edge identification for the six directions of the ( l , s , Y) space. Three compound
stimuli combining two orthogonal directions were chosen and included with the end-points in five randomly interleaved staircases. For
combinations of Y with l -chromaticity, or l - with s -chromaticity, probability summation was observed.
Combinations of Y with s -chromaticity revealed opponency. Data
for + s , +Y and − s , −Y were subadditive;
data for + s , −Y and − s , +Y were additive.
Control studies using detection rather than edge identification revealed probability summation for all combinations. Luminance edges
did not enhance stimuli with l -chromaticities. There was an
interaction of luminance edges with s -chromaticities. Dim
“blues” and bright “yellows” showed linear summation. Bright “blues” and dim “yellows”
showed opponency.
Type of Medium:
Online Resource
ISSN:
0952-5238
,
1469-8714
DOI:
10.1017/S0952523804213220
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2004
detail.hit.zdb_id:
1489922-X
SSG:
12
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