The Effects of Target Borders on Dynamic Visual Acuity: Practical and Theoretical Implications

Perception ◽  
1988 ◽  
Vol 17 (6) ◽  
pp. 745-751 ◽  
Author(s):  
Gerald M Long ◽  
Philip M Garvey
Keyword(s):  
Visual Acuity ◽  
Spatial Frequency ◽  
Frequency Component ◽  
Neural Mechanisms ◽  
Moving Targets ◽  
Dynamic Visual Acuity ◽  
Stimulus Energy ◽  
Spatial Frequency Component ◽  
Slow Moving ◽  
Practical Implications

The effects of target borders on the ability of observers to resolve moving targets (Landolt Cs) under a range of conditions were examined. Contrary to reported findings with stationary targets, it was predicted that the presence of borders would improve acuity for slow-moving targets because (i) overall stimulus energy is kept relatively constant as target detail varies, and (ii) a low-spatial-frequency component is held constant as target detail varies. In an experiment in which a two-sided border (above and below the target) was used, the predicted beneficial effect of the border at slow speeds was obtained. The results are discussed in terms of practical implications for the assessment of dynamic visual acuity as well as the potential neural mechanisms underlying performance.

scholarly journals Visual acuity of budgerigars for moving targets

Biology Open ◽  
2021 ◽  
Author(s):  
Sandra Chaib ◽  
Juliane Gaviraghi Mussoi ◽  
Olle Lind ◽  
Almut Kelber
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Spatial Frequency ◽  
Detection Threshold ◽  
Moving Targets ◽  
Resolution Limit ◽  
Food Items ◽  
Visual Spatial ◽  
Behavioural Tests ◽  
Circular Target

For a bird, it is often vital to visually detect food items, predators, or individuals from the same flock, i.e. moving stimuli of various shapes. Yet, behavioural tests of visual spatial acuity traditionally use stationary gratings as stimuli. We have behaviourally tested the ability of budgerigars (Melopsittacus undulatus) to detect a black circular target, moving semi-randomly at 1.69 degrees second−1 against a brighter background. We found a detection threshold of 0.107±0.007 degrees of the visual field for target size corresponding to a resolution of a grating with a spatial frequency of 4.68 cycles degree−1. This detection threshold is lower than the resolution limit for gratings but similar to the threshold for stationary single objects of the same shape. We conclude that the target acuity of budgerigars for moving single targets, just as for stationary single targets, is lower than their acuity for gratings.

A Comparison between Methods for Assessing the Resolution of Moving Targets (Dynamic Visual Acuity)

Perception ◽  
1996 ◽  
Vol 25 (12) ◽  
pp. 1389-1399 ◽  
Author(s):  
Gerald M Long ◽  
Dawn M Johnson
Keyword(s):  
Visual Acuity ◽  
Target Duration ◽  
Target Velocity ◽  
Channel Activity ◽  
Moving Targets ◽  
Dynamic Visual Acuity ◽  
Dependent Variables ◽  
Two Measures ◽  
Future Work

A comparison was made between two measures of visual functioning in a dynamic context that required the resolution of moving targets. Performance obtained on a traditional task of dynamic visual acuity, which involves the determination of the smallest target that can be resolved at a given target velocity, was compared with that obtained with an alternative task that essentially reverses the independent and dependent variables. Generally similar patterns of results were obtained across the two procedures, but the alternative procedure appears to offer several advantages such as greater ease of administration, improved precision of measurement, and more-direct assessment of underlying channel activity. The recommended use of the new procedure in future work involving dynamic acuity as well as particular variables that should be carefully controlled in such work (eg target duration and target size) are discussed.

Low- and mid-spatial-frequency component measurement for aspheres

2003 ◽  
Author(s):  
Michael Schulz ◽  
Ingolf Weingaertner ◽  
Clemens Elster ◽  
Joachim Gerhardt
Keyword(s):  
Spatial Frequency ◽  
Frequency Component ◽  
Spatial Frequency Component

Training Effects on the Resolution of Moving Targets—Dynamic Visual Acuity

1989 ◽  
Vol 31 (4) ◽  
pp. 443-451 ◽  
Author(s):  
Gerald M. Long ◽  
David A. Rourke
Keyword(s):  
Visual Acuity ◽  
Test Session ◽  
Moving Targets ◽  
Dynamic Visual Acuity ◽  
Training Effects ◽  
Final Test ◽  
Male College

In initial 60-min sessions, the dynamic visual acuity (DVA)of 54 male college observers was determined over a range of target velocities (60, 90, 120, and 150 deg/s) at each of three durations (200, 400, and 600 ms). Following four 30-min practice sessions with the task, a final test session identical to the first was then conducted. Highly significant training effects on DVA were obtained; contrary to previous work, these effects were most marked for observers with initially poorer performance.

scholarly journals Effects of caffeine ingestion on dynamic visual acuity: a placebo-controlled, double-blind, balanced-crossover study in low caffeine consumers

2021 ◽  
Author(s):  
Beatríz Redondo ◽  
Raimundo Jiménez ◽  
Rubén Molina ◽  
Kristine Dalton ◽  
Jesús Vera
Keyword(s):  
Visual Acuity ◽  
Crossover Study ◽  
Random Order ◽  
Random Motion ◽  
Caffeine Intake ◽  
Moving Targets ◽  
Dynamic Visual Acuity ◽  
Double Blind ◽  
Caffeine Ingestion ◽  
Motion Paths

Abstract Background Acute caffeine ingestion has been associated with improvements in cognitive performance and visual functioning. The main objective of this study was to determine the effects of caffeine intake on dynamic visual acuity (DVA). Methods Twenty-one low caffeine consumers (22.5 ± 1.6 years) took part in this placebo-controlled, double-blind, and balanced crossover study. In two different days and following a random order, participants ingested either caffeine (4 mg/kg) or placebo, and DVA was measured after 60 min of ingesting the corresponding capsule. A recently developed and validated software (moV& test, V&mp Vision Suite, Waterloo, Canada) was used to assess DVA. Results We found a greater accuracy for both the horizontal and random motion paths of DVA after caffeine ingestion (p < 0.001 and p = 0.002, respectively). In regard to the speed of the response, our data revealed that caffeine intake was associated with a faster reaction time for horizontally (p = 0.012) but not for randomly (p = 0.846) moving targets. Also, participants reported higher levels of perceived activation after consuming caffeine in comparison to placebo (p < 0.001). Conclusions Our data suggest that caffeine intake (i.e., a capsule containing 4 mg/kg) has an ergogenic effect on DVA, which may be of special relevance in real-word contexts that require to accurately and rapidly detect moving targets (e.g., sports, driving, or piloting).

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