What adjusts pupil size to allow light into the eye?
Iris
Cone cells
- day/high intensity light (>50% illumination)
- identifies Colors
- high visual acuity
Rod cells
- low light
- identifies outlines and motion
- vision in peripheral regions
- no colors, poor resolution
- produce rhodopsin
Night blind spot
- fovea centralis
- only cones
- 5-10deg wide
- provides most visual information
Day blind spot
- optic disk
- where the optic nerve enters the eye
- compensated by binocular vision
Types of vision
Photopic: Daylight, artificial light; central vision
Mesopic: Twilight, moonlight, NVG; most dangerous
Scotopic: Partial moon, stars; off-center vision
Rhodopsin
- 30-45min to buildup
- bleached out by bright light
Visual acuity
Best NVG vs worst NVG vs best unaided
20/25
20/70
20/200
Stop-turn scanning technique
- Z-pattern, stop between turns
- 10deg overlap
Binocular cues
- convergence
- stereopsis
Monocular cues
- geometric perspective
- retinal image size
- aerial perspective
- motion parallax
ANVIS Parts
Objective lens
- minus blue filter
Eyepiece lens
-
PAS
- grab ANVIS only here
Electrical contacts
- clean with pencil eraser
Operational defects
Shading
Emission points
Edge glow
Flashing/Flickering/Intermittent Operation
Natural light sources
Moon (15deg/s)
Sun
Stars
Protective functions
Automatic Brightness Control (ABC)
Bright Source Protection (BSP)
