Monocular versus Binocular Contrast Thresholds for Movement and Pattern

Perception ◽  
1978 ◽  
Vol 7 (2) ◽  
pp. 195-200 ◽  
Author(s):  
David Rose
Keyword(s):  
Nerve Cell ◽  
Binocular Vision ◽  
Apparent Movement ◽  
Monocular Vision ◽  
Pattern Detection ◽  
Pattern Perception ◽  
Sinusoidal Grating ◽  
Movement Detection ◽  
Linear Summation ◽  
Contrast Thresholds

The superiority of binocular vision over monocular vision has been compared for the detection of stationary sinusoidal grating patterns, and for the detection of the apparent movement induced by rapidly phase-reversing such gratings. The thresholds for binocular and monocular pattern perception were in the ratio 1: 2 1/2, as found by previous workers. For apparent movement, however, binocular thresholds were lower than monocular thresholds by a factor of 1 ·9; for every subject tested ( n = 20) the ratio for movement detection was larger than the ratio for pattern detection. The effects of combining inputs from the two eyes cannot be explained solely by linear summation models, but may in some circumstances depend on the nonlinearities of certain types of nerve cell.

Binocular Vision Enhances Target Detection by Filtering the Background

Perception ◽  
1994 ◽  
Vol 23 (11) ◽  
pp. 1267-1286 ◽  
Author(s):  
Bruce Schneider ◽  
Giampaolo Moraglia
Keyword(s):  
Target Detection ◽  
Binocular Vision ◽  
Gaussian Noise ◽  
Visual Scene ◽  
Sinusoidal Grating ◽  
Model Based

In previous studies the authors have shown that the enhanced detectability exhibited by stereoscopically viewed targets can be accounted for by assuming that the binocular system can linearly summate the left-eye and right-eye views of a visual scene. A model based upon this assumption leads to a variety of predictions concerning the detectability of noise-embedded targets. One such prediction is that the detectability of a target in these conditions is highly orientation specific. A test is reported of such a prediction that can be regarded as counterintuitive: namely, that the detectability, under stereoscopic viewing conditions, of a patch of sinusoidal grating masked by Gaussian noise should change substantially when the grating, oriented at 45°, is rotated until its orientation becomes −45°. The implications of these results for an understanding of the phenomenon of camouflage breaking are discussed.

An Assessment of Decision-Making as a Possible Factor in the Age-Related Loss of Contrast Sensitivity

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 541-552 ◽  
Author(s):  
James D Morrison ◽  
James Reilly
Keyword(s):  
Decision Making ◽  
Contrast Sensitivity ◽  
Contrast Threshold ◽  
Sinusoidal Grating ◽  
Hit Rate ◽  
Grating Pattern ◽  
Age Related ◽  
Spatial Frequencies ◽  
Young Subjects ◽  
Contrast Thresholds

The possibility that changes in decision-making may contribute to the age-related decline in contrast sensitivity has been investigated in nineteen young subjects (ages 21–38 years) and twenty-seven old subjects (ages 55–92 years). A signal detection paradigm was employed in which the detection of stationary sinusoidal grating patterns was measured at 3 and 15 cycles deg−1 for a range of contrasts which were psychophysically equivalent for each subject. A decline in contrast sensitivity with age at the spatial frequencies studied was confirmed for contrast thresholds obtained both by the ascending method and from the 50% hit rate for detection of the grating pattern. The criterion adopted for decision-making, expressed as both β and percentage bias, did not change significantly between young and old subjects at 15 cycles deg−1. At 3 cycles deg−1, criterion β did not change significantly at x0.8, x1.0, or x1.2 contrast threshold, but at contrast giving 50% hit rate there was a significant increase with age. The percentage bias increased significantly at contrast threshold but not at 50% hit rate. It is inferred from the results that the loss of contrast sensitivity was not accountable in terms of the adoption of a more conservative criterion by older subjects. Hence visual loss in ageing is attributed to changes within the visual pathway rather than within higher decision-making centres.

Fused Binocular Vision is Required for Development of Proper Eye Alignment in Barn Owls

1989 ◽  
Vol 2 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Eric I. Knudsen
Keyword(s):  
Binocular Vision ◽  
Early Life ◽  
Receptive Fields ◽  
Monocular Vision ◽  
Tyto Alba ◽  
Active Process ◽  
Binocular Fusion ◽  
Barn Owls ◽  
Eye Alignment ◽  
The Brain

AbstractThe eyes of adult barn owls (Tyto alba) are virtually fixed in the head in positions that are highly consistent from one individual to the next. However, early in development the eyes are exodeviated; the eyes achieve their adult positions during the owl's second month of life. Disruption of binocular vision in baby owls leads to permanent, highly abnormal eye positions and interocular alignment. Of three owls raised with both eyelids sutured closed, two developed exotropic strabismus and one developed esotropic strabismus. Two owls reared with monocular vision developed esotropic strabismus, whereas three owls reared with fused, but optically deviated binocular vision developed normal eye positions. Thus, the alignment of the eyes in adults results from an active process that depends on fused binocular vision during early life.Extracellular microelectrode recordings from the optic tecta of strabismic owls reveal that many units retain binocular inputs from corresponding points of the two eyes: the left-eye and right-eye receptive fields of individual units are misaligned by an amount predicted by the direction and magnitude of the strabismus. These results indicate that an innately determined pattern of connections in the brain anticipates the eye positions necessary to achieve binocular fusion. The hypothesis is put forth that the powerful activation of such binocular neurons by strong, synchronous inputs from the two eyes is the signal required by the optimotor system that proper eye alignment has been attained.

scholarly journals The role of binocular vision in walking

2009 ◽  
Vol 26 (1) ◽  
pp. 73-80 ◽  
Author(s):  
MARY HAYHOE ◽  
BARBARA GILLAM ◽  
KELLY CHAJKA ◽  
ELIA VECELLIO
Keyword(s):  
Binocular Vision ◽  
Monocular Vision ◽  
Stereoscopic Vision ◽  
Eye Position ◽  
Visually Guided ◽  
Extensive Investigation ◽  
Foot Placement ◽  
Walking Performance ◽  
The Difference

AbstractDespite the extensive investigation of binocular and stereoscopic vision, relatively little is known about its importance in natural visually guided behavior. In this paper, we explored the role of binocular vision when walking over and around obstacles. We monitored eye position during the task as an indicator of the difference between monocular and binocular performances. We found that binocular vision clearly facilitates walking performance. Walkers were slowed by about 10% in monocular vision and raised their foot higher when stepping over obstacles. Although the location and sequence of the fixations did not change in monocular vision, the timing of the fixations relative to the actions was different. Subjects spent proportionately more time fixating the obstacles and fixated longer while guiding foot placement near an obstacle. The data are consistent with greater uncertainty in monocular vision, leading to a greater reliance on feedback in the control of the movements.

Case Study: Restoration of Binocular Vision to a Functionally Monocular Sighted Adult

1970 ◽  
Vol 30 (3) ◽  
pp. 939-943
Author(s):  
P. A. Fried
Keyword(s):  
Color Vision ◽  
Binocular Vision ◽  
Depth Perception ◽  
Normative Data ◽  
Visual Illusions ◽  
Monocular Vision

Binocular vision was restored to a 26-yr.-old woman who had had, functionally, monocular vision since infancy. Testing was carried out a few hours and 2 wk. after restoration. The normative, data obtained from testing on such items as color vision, visual illusions, depth perception, and recognition thresholds are discussed.

The Binocular Combination of Chromatic Contrast

Perception ◽  
10.1068/p5279 ◽  
2005 ◽  
Vol 34 (8) ◽  
pp. 1035-1042 ◽  
Author(s):  
David R Simmons
Keyword(s):  
Contrast Sensitivity ◽  
Chromatic Contrast ◽  
Linear Summation ◽  
Binocular Interactions ◽  
Contrast Thresholds

How is chromatic contrast combined binocularly? One index of binocularity is the binocular contrast summation ratio (BCSR), which is the improvement in contrast sensitivity with binocular rather than monocular presentation. Simmons and Kingdom (1998, Vision Research38 1063–1071) noted that BCSRs with some red-green isoluminant stimuli were suggestive of full linear summation. This suggestion was investigated further in four subjects by measuring binocular and monocular contrast thresholds for the detection of 0.5 cycle deg−1 isoluminant (red-green) and isochromatic (yellow-black) Gabor patches. These Gabor patches had either vertically or horizontally oriented carrier gratings and were either dichoptically in phase (same coloured bars in binocular correspondence) or in dichoptic anti-phase (opposite coloured bars in binocular correspondence). Full linear summation would be indicated by BCSRs of 2 for the in-phase and close to 0 for the anti-phase conditions. Mean BCSRs at isoluminance were 1.93 and 0.90, respectively, for the in-phase and anti-phase stimuli with horizontal carriers, the former being consistent with full linear summation, but the latter not. Despite these results, BCSRs obtained with isoluminant and isochromatic stimuli under similar conditions were not statistically distinguishable from each other, although there was a tendency for summation at isoluminance with in-phase stimuli to be higher and anti-phase stimuli to be lower. These data fall short of demonstrating full linear summation of chromatic contrast between the eyes under all presentation conditions, but they do indicate that there are strong binocular interactions at red-green isoluminance, which are similar to, and possibly even stronger than, those obtained with luminance stimuli.

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