Effects of Luminance, Contrast, and Blur on Visual Acuity

Johnson, Chris A.; Casson, Evanne J.

doi:10.1097/00006324-199512000-00004

Cited by 105 publications

(89 citation statements)

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“…This is probably due to nonuniform changes in visual acuity with increasing degrees of induced myopia. Johnson and Casson 17 reported that the slope of changes in visual acuity was steeper at low levels of induced myopia up to approximately ϩ2D than at higher levels of myopic defocus from ϩ2D to ϩ8D. The dramatic decrease in visual acuity for blur levels up to nearly ϩ2D is in agreement with the results of this study that reveal marked reduction of BOLD responses from no myopia to myopic states.…”

Section: Discussionsupporting

confidence: 90%

Effect of Lens-Induced Myopia on Visual Cortex Activity: A Functional MR Imaging Study

Mirzajani¹,

Sarlaki²,

Kharazi³

et al. 2011

AJNR Am J Neuroradiol

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Section: Discussionsupporting

confidence: 90%

Effect of Lens-Induced Myopia on Visual Cortex Activity: A Functional MR Imaging Study

Mirzajani¹,

Sarlaki²,

Kharazi³

et al. 2011

AJNR Am J Neuroradiol

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“…The results supports the findings of Johnson and Casson (1995) who proved that human perception is influenced by blur. Furthermore, it shows also that blur influences photogrammetric image processing and in contrast to human perception, image processing procedures are more sensitive to blur.…”

Section: Blur Disturbssupporting

confidence: 91%

Uav Image Blur – Its Influence and Ways to Correct It

Sieberth

Wackrow

Chandler

2015

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Unmanned aerial vehicles (UAVs) have become an interesting and active research topic in photogrammetry. Current research is based on image sequences acquired by UAVs which have a high ground resolution and good spectral resolution due to low flight altitudes combined with a high-resolution camera. One of the main problems preventing full automation of data processing of UAV imagery is the unknown degradation effect of blur caused by camera movement during image acquisition.The purpose of this paper is to analyse the influence of blur on photogrammetric image processing, the correction of blur and finally, the use of corrected images for coordinate measurements. It was found that blur influences image processing significantly and even prevents automatic photogrammetric analysis, hence the desire to exclude blurred images from the sequence using a novel filtering technique. If necessary, essential blurred images can be restored using information of overlapping images of the sequence or a blur kernel with the developed edge shifting technique. The corrected images can be then used for target identification, measurements and automated photogrammetric processing.

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“…It decreases with decreasing illumination (Ferree and Rand 1923;Hecht 1928;Johnson and Casson 1995;Lachenmayr 2003;Mainster and Timberlake 2003;Morgan and King 1995;Mortimer and Fell 1989;Shlaer 1937;Sturgis and Osgood 1982;Wilcox 1932). In mesopic light conditions, such as during night driving, VA drops to about half of the photopic acuity (Lachenmayr 2003(Lachenmayr , 2006Walsh 1965).…”

Section: Mesopic Visual Acuitymentioning

confidence: 99%

Vision and Night Driving Abilities of Elderly Drivers

Gruber

Mosimann

Müri

et al. 2013

Traffic Injury Prevention

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Objective:In this article, we review the impact of vision on older people's night driving abilities. Driving is the preferred and primary mode of transport for older people. It is a complex activity where intact vision is seminal for road safety. Night driving requires mesopic rather than scotopic vision, because there is always some light available when driving at night. Scotopic refers to night vision, photopic refers to vision under well-lit conditions, and mesopic vision is a combination of photopic and scotopic vision in low but not quite dark lighting situations. With increasing age, mesopic vision decreases and glare sensitivity increases, even in the absence of ocular diseases. Because of the increasing number of elderly drivers, more drivers are affected by night vision difficulties. Vision tests, which accurately predict night driving ability, are therefore of great interest.Methods: We reviewed existing literature on age-related influences on vision and vision tests that correlate or predict night driving ability.Results: We identified several studies that investigated the relationship between vision tests and night driving. These studies found correlations between impaired mesopic vision or increased glare sensitivity and impaired night driving, but no correlation was found among other tests; for example, useful field of view or visual field. The correlation between photopic visual acuity, the most commonly used test when assessing elderly drivers, and night driving ability has not yet been fully clarified.Conclusions: Photopic visual acuity alone is not a good predictor of night driving ability. Mesopic visual acuity and glare sensitivity seem relevant for night driving. Due to the small number of studies evaluating predictors for night driving ability, further research is needed.

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Effects of Luminance, Contrast, and Blur on Visual Acuity

Cited by 105 publications

References 0 publications

Effect of Lens-Induced Myopia on Visual Cortex Activity: A Functional MR Imaging Study

Effect of Lens-Induced Myopia on Visual Cortex Activity: A Functional MR Imaging Study

Uav Image Blur – Its Influence and Ways to Correct It

Vision and Night Driving Abilities of Elderly Drivers

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