1. Night Vision Goggle Operations
NVG
Night Vision Goggle Operations

2. Presented By:
Capt John Withelder
39th Rescue Squadron

3. HUMOR TIME

6. Iraqui Navy

10. Turning Night Into Day

11. Overview The visual process Components of Vision
NVG Theory and Development
NVG Components
Types of NVGs
Visual Performance
NVG Limitations
Welcome to the NVG Lab

12. The Visual Process
Cone cells - (day vision, require high light, best for resolution and color vision)
Rod cells - (night vision, low level light, best for peripheral vision, blind spot at Fovea)

13. Components of Vision Focal Vision Ambient Vision ( peripheral vision)
Limited to the central 2° of vision (Fovia)
Consious function, slow process
Allows one to clearly identify objects/read displays
Ambient Vision ( peripheral vision)
subconsious function, primary role to orient an individual in the environment.
Works with focal vision to provide spacial orientation

14. Components of Vision Dark adaptation varies between people
sensitivity increase 10,000 fold first 30 minutes
complete adaptation 30 to 45 minutes
Extreme exposure to bright light may destroy dark adaptation for hours, even days.
NVG image perceived in shades of green using both rods and cones. ( dark adaptation critical)

15. NVG Theory Electro-optical system NVGs collect reflected ambient light
Invert and focus image on image intensifier
Image intensifier convert light into electrons
Electrons stikes phosphor screen creating visible image
Image reinverted by fiber optics and transmitted to eye-piece

16. NVG Theory Illuminence (illumination) Luminance Albedo
light striking an object/surface at a distance
ex. Moonlight striking the ground
Luminance
amount of light reflected from a surface
ex. Moonlight reflected from the terrain
Albedo
ratio between illuminence and luminance
NVGs intensify reflected energy (luminence)

17. Electromagnetic Spectrum

18. NVG Development World War II IR (Infra-red) exploitations
Early 60’s Army NVG work
Generation I tubes
Heavy/awkward/Starlight Scope
Generation II tubes
Early 70’s development
Microchannel plate
Shorter/lighter/helmet mounted
Generation III tubes
intensifier tube into the near IR spectrum
“Gallium Arsenide” photocathode (Starlight level performance)
What we use now

19. NVG Development Gen 2 vs. Gen 3 Performance

20. NVG Components (Gen 3) Advanced night vision system
Binocular style, helmet mounted
Amplify visible and near IR energy
Passive process, no emission by goggles
Image is green due to phosphor type used.

21. NVG Components (Gen 3)

22. Night Vision Goggles

23. Types of NVGs Direct View USAF AN/AVS-6 ( ANVIS) Indirect View Type I
Type II
Direct View
USAF AN/AVS-6 ( ANVIS)
Optical performance better
Type used in HC-130/HH60 Ops.
Indirect View
Use of combiner glass to reflect image on HUD
Less obstruction to pilots field of view

24. NVG Specifications LIMITS: VERTICAL MOTION- 19.5mm 16mm
AN/AVS AN/AVS-9
VERTICAL MOTION mm mm
FORE AND AFT mm mm
TILT /-5 degrees
EYE SPAN mm-72mm
OBJECTIVE FOCUS mm--> <61cm-->
FIELD OF VIEW degrees
MAGNIFICATION UNITY 1X
WEIGHT g g
OPERATING TEMPERATURE F to +125F
STORAGE TEMPERATURE F to +159F
COST BETWEEN $7500 and $8500

25. Visual Performance Vision limited while using NVGs
Detection ranges increase
Recognition of targets, terrain severly limited
NVGs Do Not Turn Night Into Day !!

26. NVG Limitations Field of View (FOV) (peripheral vision)
Current Type I NVGs, 40° FOV
Current Type II NVGs 30° FOV
Normal eye vision FOV 120° x 80°
Resolution capability of 20/25 to 20/40 Snellen
Exceeds eyes unaided night vision of 20/200 to 20/400

27. NVG Limitations Depth perception and distance estimation
NVGs degrade capability of distance estimation
NVGs will not correct for sight deficiencies.
NVG use incurres loss of contrast and definition.
Reduction in FOV requires aggressive visual scan technique.

29. NVG Rescue

30. FLIR Video

31. Questions ?

32. Welcome to the NVG Lab Review NVG Adjustment video
Wear NVGs in the “visual test lane”