Fixed Pattern Noise - ATN NVM14 Operator's Manual

3. BLACK SPOTS.
these are cosmetic blemishes in the image intensifier or dirt or de-
bris between the lenses. Black spots are acceptable as long as
they do not interfere with viewing the image. No action is required
if this condition is present unless the spots interfere with the
usability of the device.
4. FIxeD-PATTeRN NOISe.
this is usually a cosmetic blemish characterized by a faint hex-
agonal (honeycomb) pattern throughout the viewing area that most
often occurs at high light levels or when viewing very bright lights
(Figure 5.4). this pattern can be seen in every image intensifier if
the light level is high enough. This condition is acceptable as
long as the pattern does not interfere with viewing the image
and usability of the device.
FIGURe 5.4. FIxeD-PATTeRN NOISe
5-5