3-5
C. Black Spots.
These are cosmetic blemishes in the image intensifiers or dirt or
debris between the lenses. Black spots are acceptable as long
as they do not interfere with viewing the image.
No action is re-
quired if this condition is present unless the spots interfere
with the usability of the device.
D. Fixed-Pattern Noise.
This is usually a cosmetic blemish characterized by a faint hexag-
onal (honeycomb) pattern throughout the viewing area that most
often occurs at high light levels or when viewing very bright lights
(See Figure 3-4). This pattern can be seen in every image intensi-
fier if the light level is high enough.
This condition is acceptable
as long as the pattern does not interfere with viewing the im-
age and usability of the device.
Figure 3-4
Fixed-Pattern Noise
Summary of Contents for PS-27
Page 7: ...1 1 SECTION I introduction...
Page 17: ...2 1 SECTION II operating instructions...
Page 31: ...3 1 SECTION III OPERATIONAL DEFECTS...
Page 37: ...4 1 SECTION IV maintenance instructions...
Page 54: ...INFO 2...
Page 55: ...INFO 3...
