NVS Flashcards
Frozen video
Loss of video link communication and results in a VIDEO FROZEN message in the status section of the
Video will freeze if missing 10 frames, if not restored in 4 sec, video will be removed
Degraded video
Due to code work error, missing column count, or cycle redundancy check within tads/pnvs
A portion of the video will be degraded, VIDEO DEGR message
Loss of BUS communication
Affected turret will move to the fixed forward position within 5 sec
If DTV is selected, sensor will change to FLIR
Dead channel
Results in a failed detector, there will be a horizontal line in the video
Flashing channels
Caused by intermittent detectors appears as horizontal broken line or line segments.
May alternate between black and white and may flash
Cloud shifting
Appears as a lighter cloud on the horizon as a result of DRC (dynamic range compression) and IR detector non-uniformity
The non-uniform lines appear as a cloud and may shift up and down through light regions of the horizon
DRC effect
When viewing linear vertical scene, the near and far areas will appear in varying shades. It will not remain constant, it will look like light moving fog
Halo effect
Occurs during low contrast scene, image enhancements may cause halos around objects
NOE Coupling
FLIR video effect in terrain flight, viewing objects above the sensor height causes a differential in color due to what is behind the object
Difficult to exploit, ACM makes it better
Monocular cues
Geometric perspective- an object appears to have a different shape at varying distances and angles : includes linear perspective, apparent foreshortening, and vertical position in the field
Retinal image size- the image the retina is focused on is perceived by the brain to be a certain size. : includes known size of objects, increasing decreasing size of objects, terrestrial association, overlapping contours
Aerial perspective- an objects clarity and shadow are perceived by the brain for determining distance : includes fading colors or shades, loss of detail or texture, position of light source/ shadow
Motion parallax- apparent relative motion of a stationary object from a moving observer (your moving, but perceive the world moving and you’re stationary). Closer objects are observed to be moving quickly, while objects farther away look to be moving slowly.
Geometric perspective
Linear perspective: parallel lines (railroad tracks) appearing to converge at as distance increases
Apparent foreshortening: the shape of an object or terrain feature appears distorted when viewed from a higher or lower altitude. Increasing altitude and distance helps this from happening
Vertical position in the field: objects of terrain features at greater distances appear higher in the field than closer objects
Retinal image size
Known size of objects: the closer an object is, the closer it appears, knowing the size of the object can help the brain determine distance
Increasing and decreasing size: if the image is getting bigger, its moving closer, if the image is getting smaller its moving away
Terrestrial association: objects that are know to “be together” can be used to determine distance, eg airfield and a plane, can be assumed to be about the same distance away
Overlapping contours: an object partially concealed by another object is at a farther distance away/ behind that object
Aerial perspective
Fading colors and shades: the vibrancy of colors will fade with distance, similarly, fog or smoke may make objects to appear farther away than they are
Loss of detail/texture: sharpness and clarity of objects decreases with more distance, if operating near the ground or on an approach pilot can use the ground texture and clarity to help determine airspeed and altitude
Position of light source/direction of shadow: if the shadow of an object is to towards the observer, the object is closer than the light source and visa versa
