NVG Flashcards
NVG Characteristics
D - Definition
I - Intensification (2000 to 3000x Zero Magnification)
A - Acuity (20/25 best to 20/70 Worst)
L - Limited field of view (40’ FOV)
V - voltage low indicator (approx. 30 min remaining)
P - power supply (AA Alkaline or Lithium, no mixing)
NVG Considerations
C - Color Discrimination A - Air/Ground Speed Limits L - Lights and Lighting M - Magnification W - Weather W - Weapons A - Aircraft Lighting D - Depth Perception and Distance Estimation S - Scanning Techniques O - Obstruction Detection S - Spatial Disorientation
NVG Definition
a passive light amplification/intensification system that amplifies light and provides sufficient imagery for pilotage from overcast starlight to moonlight considerations
NVG Visual Deficiencies Operational Defects
S - Shading
E - Edge Glow
E - Emission Points
F - Flashing/Flickering or Intermittent Operation
NVG Visual Deficiencies Cosmetic Blemishes
B - Bright Spots I - Image Distortion B - Black Spots I - Image Disparity C - Chicken Wire F - Fixed Pattern Noise (Honeycomb) O - Output Brightness Variation
NVG Consideration - Lights and Lighting
P - Performance Relations
E - Effects of Bright Lights
A - Automatic Brightness Control
B - Bright Source Protection
NVG Considerations - Depth Perception and Distance Estimation
D - Degree
A - Acuity
T - Type
E - Experience
Visual Illusions
H - Height-Depth Perception (loss of visual cues)
A - Autokinesis (single light appears to move)
V - Vection (Induced Motion Illusion)
F - False Horizons (sloping cloud deck/terrain,reduced vis)
F - Fascination/Fixation (task saturation, target fixation)
C - Crater Illusion (IR down, think you’re higher)
C - Confusion w/Ground Lights (w/stars)
S - Structural Illusion (precipitation, heat waves)
S - Size Distance Illusion (comparing unfamiliar size w/familiar)
A - Aerial Perspective (cues diff size or perspicuity than expected)
S - Size Constancy (wider-hi/long, narrower-lo/short)
S - Shape Constancy (down slope-hi, up slope-low)
Night Vision Techniques
S - Scanning
O - Off Center Vision
S - Shapes & Silhouettes
NVG Protection - Protective Equipment
R - Red Lighting / Red Lens Goggles
S - Supplemental Oxygen
S - Sunglasses
NVG Protection - Protective Measures
C - Cockpit Lighting
E - Exterior Lighting
L - Light Flash Compensation
NVG Protection - Light Flash Compensation
C - Close One Eye
A - Alter Course
A - Automatic Weapons Fire (short burst)
T - Turn away from lights
Night central blind spot
central or night blind spot
scotopic vision
peripheral vision
Dark Adaptation
D - Definition S - Starting Level S - Sensitivity T - Time to Adapt (30 to 45 min) T - Time to Readapt (Several to 45 minutes or longer depending on brightness, duration or after repeated exposures) (2-3 min after removing goggles)
Distance Estimation & Depth Perception
Binocular Vision
Monocular Vision
G - Geometric Perspective
L - Linear Perspective
A - Apparent Foreshortening
V - Vertical Position in the Field
R - Retinal Image Size
K - Known Size of Objects
I - Increasing/Decreasing Size
T - Terrestrial Association
O - Overlapping Contours
A - Aerial Perspective
F - Fading of Color or Shades
L - Loss of Detail or Texture
L - Light Source Position / Shadow Direction
M - Motion ParallaxDay Blind Spot
5.5 - 7.5 wide, located about 15 degrees from the fovea
No cones or rods, are present at the attachment point
compensated for by Binocular Vision
Day blind spot is always present
NT Central Blind Spot
Central or Night Blind Spot
Fovea inactive (concentration of cones)
5-10 degrees wide
Objects fade away if stared at > 2 sec
Blind spot size increases with distance
Scotopic Vision
Peripheral Vision
Types of Vision
Photopic
Mesopic
Scotopic
Height - Depth Perception
are due to absent or insufficient visual cues and cause crew members to misjudge depth perception
Autokineses
when ambient visual cues are minimal and a small, dim light is seen against a dark background
Vection
induced motion is falsely perceived motion of oneself when no physical motion is actually occurring. ex: visually induced perception of self-motion.
False Horizon
when a pilot confuses a wide sloping plane of reference such as sloping cloud tops, mountain ridges, or so called cultural lighting at night with the true horizontal
Fascination / Fixation
can be separated into two categories
-task saturation - when crew members become engrossed with a problem or task within the cockpit that they fail to properly scan outside the aircraft
-target fixation - when crew members ignore orientation cues and focus their attention on an object or goal
Crater Illusion
when crew members land at night under night vision device conditions and the infrared searchlight is directed too far under the aircraft’s nose
Confusion w/Ground Lights
pilot mistakes ground lights for stars.
Structural Illusion
caused by the effects of rain, snow, sleet, heat waves, or other visual obscurants
Size - Distance Illusion
crew member misinterprets an object of unfamiliar size and shape by comparing it with what they are accustomed or familiar to seeing based on experience
Aerial Perspective
can occur if visual cues are of a different size or perspicuity than expected
Size Constancy
a runway that is narrower than expected may cause the pilot to think he or she is higher and further away resulting in the flying of the approach too low and land short
Shape Constancy
than up sloping runway may give the pilot the illusion of being too high. and vise versa
