An investigation of stereopsis with AN/AVS-6 night vision goggles at varying levels of illuminance and contrast
<p>The increased reliance on night operations by the military over the last few decades has led to the development of various night imaging devices. Night vision goggles (NVGs) are one device which have gained widespread use in nighttime helicopter operations. However, rotorcraft accident data...
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| Format: | Others |
| Language: | en |
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/46237 http://scholar.lib.vt.edu/theses/available/etd-12162009-020156/ |
| Summary: | <p>The increased reliance on night operations by the
military over the last few decades has led to the
development of various night imaging devices. Night vision
goggles (NVGs) are one device which have gained widespread
use in nighttime helicopter operations. However, rotorcraft
accident data have indicated an increased occurrence of
"pilot error" type accidents when NVGs are in use. NVG
related accidents often can be linked to extremely poor
ambient lighting and contrast conditions during nighttime
operations as well as the imaging limitations of the NVGs.
Research has shown that NVGs reduce visual acuity and depth
perception when compared to unaided daylight viewing
conditions.</p><p>
In this study the effects of illumination and contrast
on stereoscopic vision with and without AN/AVS-6 goggles
were investigated. Stereoacuity was measured using a
modified Howard-Dolman apparatus with four levels of
illumination and three levels of contrast. Testing was performed with NVGs for nighttime illuminations and unaided
for daytime levels of illumination. Image measurements were
performed on the NVGs to determine the impact of
illumination on resolution and signal-to-noise ratio.</p><p>
Stereoscopic vision with NVGs was found to be
significantly worse than under daylight conditions. Low
levels of contrast also were found to reduce stereoacuity
significantly. It was found that the worst stereoacuity in
this study occurred under half moon or higher illumination
levels. This research revealed that further NVG development
should focus on the limitations of the NVGs under high light
levels, and special considerations should be made for using
NVGs in low contrast, high luminance situations.</p> === Master of Science |
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