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 (See 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 interfere with the ability to perform the mission.
Figure 5-4
Fixed Pattern Noise
