Laser-induced retinal damage threshold as a function of retinal image size

1999 ◽  
Author(s):  
Joseph A. Zuclich ◽  
David J. Lund ◽  
Peter R. Edsall ◽  
Richard C. Hollins ◽  
Peter A. Smith ◽  
...  
Keyword(s):  
Retinal Image ◽  
Damage Threshold ◽  
Retinal Damage ◽  
Image Size

Variation of laser-induced retinal damage threshold with retinal image size (Abstract Only)

2000 ◽  
Author(s):  
Joseph A. Zuclich ◽  
David J. Lund ◽  
Peter R. Edsall ◽  
Richard C. Hollins ◽  
Peter A. Smith ◽  
...  
Keyword(s):  
Retinal Image ◽  
Damage Threshold ◽  
Retinal Damage ◽  
Image Size

Variation of laser induced retinal-damage threshold with retinal image size

2000 ◽  
Vol 12 (2) ◽  
pp. 74-80 ◽  
Author(s):  
Joseph A. Zuclich ◽  
Peter R. Edsall ◽  
David J. Lund ◽  
Bruce E. Stuck ◽  
Richard C. Hollins ◽  
...  
Keyword(s):  
Retinal Image ◽  
Damage Threshold ◽  
Retinal Damage ◽  
Image Size

New data on the variation of laser induced retinal-damage threshold with retinal image size

2008 ◽  
Vol 20 (2) ◽  
pp. 83-88 ◽  
Author(s):  
J. A. Zuclich ◽  
P. E. Edsall ◽  
D. J. Lund ◽  
B. E. Stuck ◽  
S. Till ◽  
...  
Keyword(s):  
Retinal Image ◽  
Damage Threshold ◽  
Retinal Damage ◽  
Image Size

OPTICAL LIMITING WITH CARBON SUSPENSIONS AT SELECTED WAVELENGTHS AND PULSE LENGTHS

2000 ◽  
Vol 09 (03) ◽  
pp. 243-259 ◽  
Author(s):  
DENIS VINCENT
Keyword(s):  
High Performance ◽  
Damage Threshold ◽  
Single Pulse ◽  
Retinal Damage ◽  
Carbon Particles ◽  
Threshold Data ◽  
Wide Range ◽  
Liquid Suspensions ◽  
Pulse Characteristics ◽  
Fine Carbon

High-performance liquid suspensions of fine carbon particles have been developed at DREV over the last 10 years to fulfil requirements regarding eye protection against laser radiation over a wide range of wavelengths and pulse lengths. This paper reports on the single-pulse characteristics of DREV's best limiting suspension named CBS-100 at wavelengths of 532, 751 and 1064 nm, and at pulse lengths of 0.01, 0.1, 1 and 100 μs. Some results at higher repetition rate (6 pps) and a comparison with recent retinal damage threshold data are included also.

scholarly journals Laser-induced retinal damage threshold for repetitive-pulse exposure to 100-μs pulses

2014 ◽  
Vol 19 (10) ◽  
pp. 105006 ◽  
Author(s):  
Brian J. Lund ◽  
David J. Lund ◽  
Peter R. Edsall ◽  
Victor D. Gaines
Keyword(s):  
Damage Threshold ◽  
Retinal Damage ◽  
Pulse Exposure

Size-Analysis of Retinal Images by Orientation Detectors

1980 ◽  
Vol 51 (3_suppl2) ◽  
pp. 1307-1330
Author(s):  
Willard L. Brigner
Keyword(s):  
Retinal Image ◽  
Size Analysis ◽  
Retinal Images ◽  
Image Size

A model for the determination of retinal-image size is presented. The size-analysis is based upon the range of orientation detectors activated by a stimulus. The model is applied to size aftereffects and is also used to predict changes in perceived size in configurations which may be expected to affect the range of orientation detectors activated. The relevance of the model to illusions of direction and the perceived length of lines forming angles is also discussed.

scholarly journals Mental geometry of 3D size and shape perception

2019 ◽  
Author(s):  
Akihito Maruya ◽  
Qasim Zaidi
Keyword(s):  
Projective Geometry ◽  
Retinal Image ◽  
Relative Size ◽  
Physical Distance ◽  
Image Size ◽  
3D Objects ◽  
Multiplicative Factor ◽  
The World ◽  
Size Invariance ◽  
Mechanical Objects

AbstractJudging poses, sizes and shapes of objects accurately is necessary for organisms and machines to operate successfully in the world. Retinal images of 3D objects are mapped by the rules of projective geometry, and preserve the invariants of that geometry. Since Plato, it has been debated whether geometry is innate to the human brain, and Poincare and Einstein thought it worth examining whether formal geometry arises from experience with the world. We examine if humans have learned to exploit projective geometry to estimate sizes and shapes of objects in 3D scenes.Numerous studies have examined size invariance as a function of physical distance, which changes scale on the retina, but surprisingly, possible constancy or inconstancy of relative size seems not to have been investigated for object pose, which changes retinal image size differently along different axes. We show systematic underestimation of length for extents pointing towards or away from the observer, both for static objects and dynamically rotating objects. Observers do correct for projected shortening according to the optimal back-transform, obtained by inverting the projection function, but the correction is inadequate by a multiplicative factor. The clue is provided by the greater underestimation for longer objects, and the observation that they appear more slanted towards the observer. Adding a multiplicative factor for perceived slant in the back-transform model provides good fits to the corrections used by observers. We quantify the slant illusion with relative slant measurements, and use a dynamic demonstration to show the power of the slant illusion.In biological and mechanical objects, distortions of shape are manifold, and changes in aspect ratio and relative limb sizes are functionally important. Our model shows that observers try to retain invariance of these aspects of shape to 3D rotation by correcting retinal image distortions due to perspective projection, but the corrections can fall short. We discuss how these results imply that humans have internalized particular aspects of projective geometry through evolution or learning, and how assuming that images are preserving the continuity, collinearity, and convergence invariances of projective geometry, supplements the Generic Viewpoint assumption, and simply explains other illusions, such as Ames’ Chair.

scholarly journals Temporal evolution from retinal image size to perceived size in human visual cortex

2018 ◽  
Author(s):  
Juan Chen ◽  
Irene Sperandio ◽  
Molly J. Henry ◽  
Melvyn A Goodale
Keyword(s):  
Visual Cortex ◽  
Visual Processing ◽  
Retinal Image ◽  
Feature Binding ◽  
Visual Signals ◽  
Viewing Distance ◽  
Size Constancy ◽  
Image Size ◽  
Subcortical Structures ◽  
Time Required

AbstractOur visual system affords a distance-invariant percept of object size by integrating retinal image size with viewing distance (size constancy). Single-unit studies with animals have shown that real changes in distance can modulate the firing rate of neurons in primary visual cortex and even subcortical structures, which raises an intriguing possibility that the required integration for size constancy may occur in the initial visual processing in V1 or even earlier. In humans, however, EEG and brain imaging studies have typically manipulated the apparent (not real) distance of stimuli using pictorial illusions, in which the cues to distance are sparse and not congruent. Here, we physically moved the monitor to different distances from the observer, a more ecologically valid paradigm that emulates what happens in everyday life. Using this paradigm in combination with electroencephalography (EEG), we were able for the first time to examine how the computation of size constancy unfolds in real time under real-world viewing conditions. We showed that even when all distance cues were available and congruent, size constancy took about 150 ms to emerge in the activity of visual cortex. The 150-ms interval exceeds the time required for the visual signals to reach V1, but is consistent with the time typically associated with later processing within V1 or recurrent processing from higher-level visual areas. Therefore, this finding provides unequivocal evidence that size constancy does not occur during the initial signal processing in V1 or earlier, but requires subsequent processing, just like any other feature binding mechanisms.

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