Influence of chromaticity on vernier and stereo acuity

Abstract

Vernier offset thresholds for targets modulated in luminance or isoluminantly along the L-M axis were confirmed to be equal for targets whose contrasts were equal multiples of those required for detection. On the other hand, stereoscopic depth thresholds were elevated by a factor of 10 or more for isoluminantly modulated targets. Thresholds for vernier targets are 2 or 3 times larger with a gap of 20 arcmin than for a gap of 1 arcmin for both isoluminant and luminance targets. On the other hand, stereo thresholds decrease by a factor of 2 to 3 for both classes of target over the same range. We consider our results in the light of recent electrophysiological and psychophysical evidence and co..