1. 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 “Our Night Vision capability provided the single greatest mismatch of the war” – General Barry McCaffrey, Commander 24 th Infantry Division“Our Night Vision capability provided the single greatest mismatch of the war” – General Barry McCaffrey, Commander 24 th Infantry Division

11. Overview The visual processThe visual process Components of VisionComponents of Vision NVG Theory and OperationNVG Theory and Operation NVG ComponentsNVG Components Types of NVGsTypes of NVGs Visual PerformanceVisual Performance NVG LimitationsNVG Limitations Welcome to the NVG LabWelcome to the NVG Lab

12. The Visual Process Major structures of the human eyeMajor structures of the human eye –Cornea, Iris, lens, Retina, Optic Nerve Retina contains two types of photoreceptors, Cones and Rods

13. The Visual Process Cone cells – Provide the eyes color sensitivity, about 6 to 7 million, and are concentrated on the center of the eye (day vision, require high light, best for resolution and color vision)Cone cells – Provide the eyes color sensitivity, about 6 to 7 million, and are concentrated on the center of the eye (day vision, require high light, best for resolution and color vision) Rod cells – Not color sensitive and are the most numerous, about 120 million, and more sensitive than cone cells (night vision, low level light, best for peripheral vision, blind spot at Fovea)Rod cells – Not color sensitive and are the most numerous, about 120 million, and more sensitive than cone cells (night vision, low level light, best for peripheral vision, blind spot at Fovea)

14. Components of Vision Focal VisionFocal Vision –Limited to the central 2° of vision (Fovea) –Conscious function, slow process –Allows one to clearly identify objects/read displays Ambient Vision ( peripheral vision)Ambient Vision ( peripheral vision) –subconscious function, primary role is to orient an individual in the environment. –Works with focal vision to provide spatial orientation

15. Components of Vision Dark adaptationDark adaptation –varies from person to person –sensitivity to light increases10,000 fold during the first 30 minutes of dark adaptation –complete adaptation takes 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)

16. 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 Micro channel 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

17. Electromagnetic Spectrum

18. NVG Theory NVGs are electro-optical devices that intensify (or amplify) existing light instead of relying on a light source of their ownNVGs are electro-optical devices that intensify (or amplify) existing light instead of relying on a light source of their own They collect reflected ambient light from stars, moon or sky glow made from distant man made sources (i.e. city lights)They collect reflected ambient light from stars, moon or sky glow made from distant man made sources (i.e. city lights) Captured ambient light is electronically amplified 2000 to 5000 thousand of timesCaptured ambient light is electronically amplified 2000 to 5000 thousand of times

19. NVG Theory, How They Work Users do not look through NVG’s, they see an amplified electronic image on a phosphor displayUsers do not look through NVG’s, they see an amplified electronic image on a phosphor display Light enters the NVG through an objective lens and strikes a photo cathode powered by a high energy charge from the power supply.Light enters the NVG through an objective lens and strikes a photo cathode powered by a high energy charge from the power supply. The energy charge accelerates across a vacuum inside the intensifier and strikes the phosphor screen where the image is focusedThe energy charge accelerates across a vacuum inside the intensifier and strikes the phosphor screen where the image is focused

20. NVG Theory NVG’s Invert and focus the image on an image intensifierNVG’s Invert and focus the image on an image intensifier Image intensifier convert light into electronsImage intensifier convert light into electrons Electrons strikes phosphor screen creating visible imageElectrons strikes phosphor screen creating visible image Image re-inverted by fiber optics and transmitted to eye-pieceImage re-inverted by fiber optics and transmitted to eye-piece An NVG phosphor screen is purposefully colored green because the human eye can differentiate more shades of green than any other color.An NVG phosphor screen is purposefully colored green because the human eye can differentiate more shades of green than any other color.

21. NVG Components (Gen 3)

22. NVG Development Gen 2 vs. Gen 3 Performance

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

24. Night Vision Goggles

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

26. NVG Specifications LIMITS: AN/AVS-6 AN/AVS-9 VERTICAL MOTION- 19.5mm 16mm FORE AND AFT- 15.8mm 16mm TILT- +/-5 degrees EYE SPAN- 51mm-72mm OBJECTIVE FOCUS- 254mm--> FIELD OF VIEW- 40 degrees MAGNIFICATION UNITY 1X WEIGHT- 500g 790g OPERATING TEMPERATURE- -25F to +125F STORAGE TEMPERATURE- -31F to +159F COST- BETWEEN $7500 and $8500

27. Visual Performance Vision is limited while using NVGs.Vision is limited while using NVGs. –Approximately 40 degree field of view Light detection ranges increase (missile launch), but recognition of targets and terrain severely limitedLight detection ranges increase (missile launch), but recognition of targets and terrain severely limited

28. NVG Limitations Field of View (FOV) (peripheral vision severely limited)Field of View (FOV) (peripheral vision severely limited) –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 20/40Resolution capability of 20/25 to 20/40 –Exceeds eyes unaided night vision of 20/200 to 20/400

29. NVG Limitations Degraded depth perception and distance estimationDegraded depth perception and distance estimation –NVGs degrade capability of distance estimation and depth perception –Important to remember for landing while using NVG’s NVGs will not correct for sight deficiencies, but greatly enhance unaided night vision.NVGs will not correct for sight deficiencies, but greatly enhance unaided night vision. NVG use incurs loss of contrast and definition. (New devices continue to correct this problem)NVG use incurs loss of contrast and definition. (New devices continue to correct this problem) Reduction in FOV requires a constant aggressive visual scan technique for spatial orientation.Reduction in FOV requires a constant aggressive visual scan technique for spatial orientation.

30. NVG Limitations Cockpit light and windscreen interferenceCockpit light and windscreen interference Vision degraded by weather conditions such as fog or hazeVision degraded by weather conditions such as fog or haze

31. NVG Limitation Corrections Research and development continues today or image intensifiers in the areas of longer wavelength spectral response, higher sensitivity, larger fields of view and increased resolutionResearch and development continues today or image intensifiers in the areas of longer wavelength spectral response, higher sensitivity, larger fields of view and increased resolution

33. NVG Rescue

34. FLIR Video

35. Questions ?

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