FLIR Alpha Nir User Manual page 19

Alpha NIR User's Guide 412-0007-10 Ver 150
3.2.21. Push the "Select Cur Dir button".
3.2.22. Note the IRvista histogram mean count value of the pixels in the array with
the light off. This "light off" mean count value will typically be around 350-
450 counts at 16 msec, low gain mode with skim enabled. It may be as high
as 1000 counts in high gain mode with skim enabled.
3.2.23. Adjust light box voltage so that the histogram mean is approximately 100
counts over the minimum "light off" mean count value. This is the DARK
level used in the NUC.
3.2.24. When the image's mean count value reaches 100 counts above the light off
counts and stabilizes, push the "GO" button. The light box can sometimes
take a few moments to stabilize. Once you press GO, the system acquires 64
frames of image data and averages them. Do not touch the camera, light
box, or light box power supply controls during the collection process.
3.2.25. When prompted by IRvista to set the MEDIUM source intensity, adjust the
lamp voltage until the mean value is about 400 counts above the "light off"
mean count value. Push the GO button when the light box has stabilized at
the desired mean value.
3.2.26. When prompted by IRvista to set the BRIGHT source intensity, adjust the
lamp voltage until the mean value is about 950 counts above the "light off"
mean count value. Push the GO button when the light box has stabilized at
the desired mean count value.
3.2.27. At Bad Gains Pixel Map window, note the sizes of clusters with the limits
set to 50% and 150% of the mean gain. Adjust the gain limits so that the
clusters stay within spec. We will quantitatively measure these clusters after
the NUC process is complete. The Minimum Allowed Gain number is
usually increased until too many bad pixels are found in the corner of the
image or until a cluster is too big (out of spec). The Maximum Allowed
Gain number is decreased until too many bad pixels are found in the center
of the image or until a cluster is too big. The target number of bad pixels
failed on gain should not exceed 400, which is approximately 0.5% of the
total number of pixels. Try not to grow a cluster such that it fails the spec.
Cluster spec is less than 6 for the inner zone and less than 10 for the outer
zone.
3.2.28. "Accept", Bad Gains Pixel Map.
3.2.29. Adjust the limits for the Bad Noise Pixel Map to be the same as for the Bad
Gain Pixel Map. Be careful to not overcorrect for Pixels with bad noise.
The number of bad noise pixels should not exceed 400 minus the number of
Bad Gain pixels. For example, there may be only 100 pixels marked as
having bad gains.
3.2.30. "Accept", Bad Noise Pixel Map.
3.2.31. "OK" at warning message.
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INDIGO OPERATIONS