BWS NVG Flashcards
CoL
What component of the eye adjusts pupil size to allow light into the eye?
Iris
CoL
_____ cells are less effective as light levels decrease
Cone
Photopic Vision
Daylight vision or under strong artificial lighting
High visual acuity and colors
Central vision
Mesopic Vision
Under twilight, full moon or ANVIS
Decreased acuity and Color perception
Central and off-Center vision
Scotopic Vision
Under partial moonlight, stars
Low acuity, no colors, only shapes/motion
Off-Center vision
CoL
Which type of vision is characterized by lack of color perception and requires off-center viewing?
Scotopic Vision
Rhodopsin
30-45min to build up
Bleached out by bright light
CoL
How long does it take to recover dark adaptation due to exposure to a bright light?
5 - 45 min depending on duration and intensity of exposure
Night Blind Spot
Occurs due to total absence of rod cells in the fovea and lack of rod cell stimulation within the parafoveal regions. Compensation via using proper scanning techniques and off center viewing
Day Blind Spot
Optic disc, contains no rods or cones. Point where optic nerve enters retina. Compensation via viewing with binocular vision
CoL
How large is the night blind spot?
5 to 10 degrees
Stop-turn-stop-turn technique
Z-pattern
Stop before each turn
10deg overlap between stops
Ten degree circular overlap
To compensate for 5-10deg night blind spot
Off center viewing
Look at target 10deg left, right, below or above to compensate for night blind spot
CoL
Why is the circular overlap in scan pattern 10 degrees?
To ensure coverage of an area greater than the night blind spot
Monocular Cues
G
R
A
M
Geometric perspective
Retinal image size
Aerial perspective
Motion parallax
Motion Parallax
Apparent, relative motion of stationary objects as viewed by a moving observer.
What information does motion parallax provide aviators?
Aircraft speed and direction of movement
ADD ALL VISUAL ILLUSIONS
Add description of the parts of NVG
Best Case NVG acuity
20/25
Worst Case NVG acuity
20/70
Unaided Visual acuity
20/200
Light spectrum and NVG sensitivity
When does the NVG spectrum starts?
600 or more
Orange/ Red Light
CoL
Which component of the Image of the Image Intensifier is responsible for creating the monochromic viewing image?
Phosphor Screen
CoL
True or False? Because the ANVIS’s eyepiece can correct for individual eye acuity, operaters are not required to wear normally required eyeglasses
False
Operational Defects
S
E
E
F
Shading
Emission Point
Edge Glow
Flashing/ Flickering and Intermittent Operation
Cosmetic Blemishes
I
F
I
C
B
O
B
Image Distortion
Fixed Pattern Noise
Image Disparity
Chicken Wire
Bright Spots
Output Brightness Variation
Black Spots
What is the biggest source of ambient light at night?
Moon (moves 15 degrees per hour)
CoL
What are the natural sources of illumination
Sun, Moon, Stars
CoL
What factors increase the likelihood of SD?
Degraded visual Acuity
Fatigue
High Task Loading
Reduced FOV
Inexperience
What do NVG see?
Normal visable spectrum plus near IR
Automatic Brightness Control…
…constantly varies the intensity of electricity applied to the Microchannel Plate to regulate the Brightness
Brightsource Protection…
…regulates the amount of electrons that hit the Microchannel Plate in case of a unexpected bright light source
CoL
If ambient light levels unexpectedly decrease, what indications may be present?
Scintillation
Change in halo intensity
Loss of celestial lights
Loss of ground lights
Noticable loss of scene detail
CoL
Battlefield light sources can negatively impact the ANVIS image due to what power supply functions being activated?
Automatic Brightness Control
Bright Source Protection
Recover Time of bright light exposure?
Up to 45 min depending on intensity of exposure
CoL
Effective use of monocular cues requires ____ and ____ in various terrain types and flight environments
Training and Experience
Most common form of LZ marking
inverted Y
Average dark adaption time
30 - 45 min
Primary considerations of command?
Crew endurance
Route Planning
Avoid ________ areas.
Bright lit
Who has to be at the formal brief?
Everybody
Distance between two light sources to mark the LZ?
15 feet
Must be supplemental light green/ red?
False
What is the most desirable instrument brightness?
Lowest easily readable brightness
Do you have to turn in the googles because of cosmetic blemishes?
No
In which time does sky glow normally takes place?
Within one hour before sunrise or after sunset
Primary side of the battery?
Right side
The ______ flexes so the light entering the eye is properly focused
on the retinal wall
Lens
________ cells are used primarily for day or high intensity light
vision (viewing periods or conditions). ________ cells are used for
night or low-intensity light vision (viewing periods or conditions).
Cone
Rod
