Night Vision Devices Flashcards
1
Q
Thats the function of the cornea?
A
It protects the eye
2
Q
What is the iris?
A
The colored membrane around the pupil
3
Q
Function of the iris
A
Adjusts the pupil size to allow light into the eye
4
Q
What is the function of the lens?
A
- To focus light on retina
- Hardens with age
5
Q
What is the retina?
A
The light sensitive part of the eye
6
Q
What component of the eye adjusts the pupil size to allow light into the eye?
A
Iris
7
Q
Cones work best in ____.
A
Daylight - 50% illumination and up
8
Q
Rods work best in _____.
A
Low light - 0% illumination and up
9
Q
Cones have a 1:_____ ratio.
A
1
10
Q
Rods have a 1:_____ ratio
A
Thousands
11
Q
What is the Fovea Centralis and what are its characteristics?
A
- Contains only cone cells
- 15* off center
- Direct or central vision
- 2 mm diameter
- 85% of visual information comes from Fovea
12
Q
What is the optic disc?
A
Where the optic nerve enters the retina
- Called the day blind spot
13
Q
What does the Parafovea contain? (Rods/cones)
A
Both rods and cones
14
Q
Which type of vision is characterized by lack of color perception and requires off center viewing?
A
Scotopic
15
Q
What is Rhodopsin and how long time does it take to build up?
A
- Chemical known as “visual purple” enabling rod cells to respond to visual stimulation
- Requires buildup to see at night
- 30-45 minutes to build up
- Bleached out by bright light
16
Q
How long times does it take to readapt after exposure to bright light?
A
From several min to 45 min depending on intensity and duration of exposures.
17
Q
What does the Peripheral region contain? (Rods/cones)
A
Rods
18
Q
Scotopic vision is when:
A
Light environment are below 50%
19
Q
Mesopic vision is when:
A
Light is between 50% and daylight
20
Q
Photopic is when:
A
Its daylight
21
Q
How to preserve your eyes?
A
- Dark sunglasses with a neutral grey tint
- Light transmission of 15% or less
- Authorized Protective Eyewear List
22
Q
How to make eyes healthy?
A
Vitamin A in the form of Milk, Cheese, Carrots, Green vegetable, Liver, Fish
- Multivitamin
23
Q
If there is bright light in the field of view of your ANVIS, the area around it will what?
A
Blacken out
24
Q
How to avoid muzzle flashes and tracers?
A
- Close or cover 1 eye
- Limit burst length
- Turn away
25
Cockpit illumination should be set to:
Lowest easily readable level
26
Night blind spot covers ____ - ____ degrees?
5-10 degrees
27
What is the cause of the day blind spot?
Optic nerve
28
How do we compensate for day blind spot?
Viewing with binocular vision
29
What is the "Field of Regard"
What you can see in a given helicopter
30
3 scanning techniques
- Stop turn technique
- Ten degree circular overlap
- Off center viewing
31
Why is the circular overlap 10*?
To ensure a cover area larger than the night blind spot
32
What are the Monocular cues?
*GRAM*
- Geometric perspective
- Retinal image size
- Aerial Perspective
- Motion parallax
33
Types of Geometric perspective:
*LAV*
- Linear perspective
- Apparent foreshortening
- Vertical Position in the field
34
Types of Retinal image size:
*KITO*
- Known size of objects
- Increasing or decreasing size of objects
- Terrestrial association
- Overlapping contours
35
Types pf Areal perspective:
*FLP*
- Fading of colors or shades
- Loss of detail or texture
- Position of light source and direction of shadow
36
What is a laser?
Intense, narrow beam of light
37
NOHD is short for:
Nominal Ocular Hazard Distance
- The minimum distance where a laser is considered to be eye safe
38
Class 1 (low energy) lasers are:
Non-hazards under all viewing conditions. Include some aiming lights and many marksmanship trainers.
39
Class 2 lasers are:
Lazer pointer and comercial scanners
- Caution do not stare directly into
40
Class 3a (medium energy) lasers are:
Generally not hazardous unless the beam is viewed directly through magnifying optics. Include lasers such as the Miniature Eye-safe Laser Infrared Observation Set (MELIOS).
41
Class 3b (medium-high power) lasers are:
Potentially dangerous if viewed directly or reflected beam with unprotected eye. Include rangefinders, pointer, illuminator and aiming lights for firearms.
42
Class 4 (high energy) lasers are:
Pulsed, visible, near-infrared laser that produce diffuse reflection, fire, skin and eye hazards. Include industrial welders and target designator lasers.
43
Safety wise class 3 and 4 lasers can be compared to:
Firearms
44
What protective measure can aviators take to ensure laser safety?
Passive:
- Take cover
- Getting out of the lasers path
- Using available protective gear
- Keeping all exposed skin covered to prevent burns
Active:
- Using countermeasures
- Applying evasive action
- Scanning with one eye or monocular optics
-Minimizing the use of binoculars
45
How much exposure time is required to cause miosis?
Dependent on amount of exposure
46
What are the visual illusions?
*F-ire F-ire F-ire CRASH CARS*
- Flicker vertigo
- False horizons
- Fascination/fixation
- Confusion w/ground lights
- Relative motion
- Altered planes of reference
- Size-Distance
- Height-depth perception
- Crater illusion
- Autokinesis
- Reversible perspective
- Structural
47
What tool can help maintain a/c control when hovering over contrast or disorienting surface?
HUD
48
What is White Hot?
The hotter the whiter and is used for target acquisition
49
What is the thermal systems ability to detect small differences in temperature called?
Minimum resolvable temperature (MRT)
50
Which polary setting is best for selecting hot spots?
White hot
51
Which lens has the anti blue coating?
Objective lens
52
The Field of view with NVGs are _____ degrees
40
53
Best NVG Visual acuity:
20/25
54
Worst NVG visual acuity:
20/70
55
Best unaided Visual acuity (at night):
20/200
56
Operational deficiencies
- Shading
- Emission points
- Edge glow
- Flashing/flickering and intermittent operation
57
Types of natural light at night:
- Moonlight (moves across the sky at 15 degrees/h)
- Starlight
- Sunlight
58
Visual illusion and Spatial D is more like to occur at night due to:
- Inexperience
- Degraded visual acuity
- Limited FOV
- High task loading
- Fatigue
59
In daytime you can use color vision and high level of visual acuity, but at night time you must rely on:
- Size
- shape
- contrast
- reflectivity
60
What factors increase the likelihood of experience visual illusion or Spatial D?
- Inexperience
- Degraded visual acuity
- Limited FOV
- High task loading
- Fatigue
61
The level of contrast at night depends on?
- Color and texture
- Level and type of ambient light
- Reflectivity
62
Types of terrain we can fly in:
- Urban
- Vegetated/rolling terrain (the best to fly NVG in)
- Mountains
- Desert
- Arctic/snow
- Over Water
63
WARNING: Exercise extreme caution when flying from ____ ambient light conditions to ____ ambient light conditions.
Under _____ light conditions the google loose some acuity that they have under _____ light conditions.
Flying from _____ to ____ light conditions quickly reduces the sharpness and definition of terrain images.
Hight , Low
Low , High
High , Low
64
High moon elevation provides:
More ambient light at a high elevation than at low elevation
65
Low moon elevation can be beneficial by:
Making minor terrain features more apparent due to the shadows that form.
- The shadows can also get to large and degrade scene detail
66
If ambient light levels unexpectedly decrease what indications may be present?
- Scintillation
- Increase in halo intensity
- Loss of celestial light
- Loss of ground light
67
Degraded visual environment includes:
- Clouds
- Fog
- Rain
- Dust
- Snow
68
Battlefield light sources can negatively impact the ANVIS image due to what power supply functions being activated?
- Automatic rightness control (ABC)
- Bright source protection (BSP)
(Both of the functions there are)
69
___ is the best tactical field lighting for a LZ
Inverted Y
70
What about night flight does 95-1 say?
You need a flashlight
71
General considerations regarding NVG mission planning:
Psychological and physiological stress
- Navigation
- Radio communication
- Battlefield light source
- Obstructions
- En route data
- Altitude changes
- Meteorology
72
The commanders considerations are:
- Crew endurance
- A/C maintenance
- Safety
- Environment
- Planning cell
