Visual Acuity and Stereopsis with Night Vision Goggles
Visual Acuity and Stereopsis with Night Vision Goggles

Author:

Publisher:

Published: 1989

Total Pages: 30

ISBN-13:

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Measurements of visual performance (stereopsis and visual resolution) were acquired to compare results achieved using unaided monocular and binocular viewing, monocular and binocular viewing with the AN/PVS-5A night vision goggles, and models A and B of the AN/PVS-7 biocular night vision goggles. All of the goggles were equipped with 2nd generation tubes. Using a modified Howard- Dolman apparatus to assess stereopsis, all of the goggle-assisted thresholds were very much larger than stereoscopic thresholds achieved with unaided binocular vision. Statistical analysis of the results indicated that stereopsis through night vision goggles, regardless of the model or viewing condition, is essentially eliminated and equivalent to the threshold obtained with unaided monocular viewing. In comparison, spatial resolution capability with all of the goggle systems is superior to performance with unaided vision. In agreement with previously published data, visual acuity with the goggles is approximately 20/ 50, but only for high contrast targets and simulated full moon ambient light levels. As light levels decrease to quarter moon conditions or target contrasts are reduced to more realistic values, visual spatial resolution with the goggles is much poorer. For infantry use, any differences in visual performance between monocular, biocular, and binocular designs probably are not operationally meaningful.

Evaluation of Visual Acuity with Gen 3 Night Vision Goggles
Evaluation of Visual Acuity with Gen 3 Night Vision Goggles

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-02

Total Pages: 42

ISBN-13: 9781722214555

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Using laboratory simulations, visual performance was measured at luminance and night vision imaging system (NVIS) radiance levels typically encountered in the natural nocturnal environment. Comparisons were made between visual performance with unaided vision and that observed with subjects using image intensification. An Amplified Night Vision Imaging System (ANVIS6) binocular image intensifier was used. Light levels available in the experiments (using video display technology and filters) were matched to those of reflecting objects illuminated by representative night-sky conditions (e.g., full moon, starlight). Results show that as expected, the precipitous decline in foveal acuity experienced with decreasing mesopic luminance levels is effectively shifted to much lower light levels by use of an image intensification system. The benefits of intensification are most pronounced foveally, but still observable at 20 deg eccentricity. Binocularity provides a small improvement in visual acuity under both intensified and unintensified conditions. Bradley, Arthur and Kaiser, Mary K. Ames Research Center ...

Visual Acuity Versus Field-of-View and Light Level for Night Vision Goggles (NVG).
Visual Acuity Versus Field-of-View and Light Level for Night Vision Goggles (NVG).

Author: Harry L. Task

Publisher:

Published: 1994

Total Pages: 21

ISBN-13:

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Parameters typically used to characterize night vision goggles (NVG) are visual acuity (resolution) and field-of-view (FOV). An increase in FOV is accomplished by providing higher magnification of the image intensifier tube. However, increased magnification means that the pixels will subtend a larger angle, thus leading to lower NVG visual acuity. An inverse relationship between visual acuity and field-of-view is expected based upon this optical/geometrical relationship. This relationship should be examined as production of NVG resolution quality increases. A trade-off study examining FOV and resolution was conducted with three observers having 20/20 corrected Snellen acuity. The NVGs had fields-of-view of 40, 47, and 52 degrees, respectively. Five levels of ambient scene illumination (corresponding to output luminance levels of 0.01, 0. 03, 0.08, 0.26, and 1.4 ft-L) were provided by a 2856K light source. The targets used in the study were 95+% contrast square wave targets ranging in size from 45 cycles/degree to 5 cycles per degree. A walk-back method of adjustment was employed. The results indicate that the geometric relationship between field-of-view and visual acuity is valid. Night vision devices, Visual acuity, Night vision goggles.