31 Spyder2 User’s Manual
03-032-10091-06 Teledyne DALSA
5. Perform Dark (FPN) calibration (see Dark Calibration on page 31).
6. Perform W hite (PRN U) cal ibration (see White Light Calibration on page 31).
7. Sav e the settings and pixel coefficients, using the commands
wus and wpc.
N ote: It is important that you run the FPN calibration first. Results of the FPN calibration
are used in the PRN U procedur e. A l so, w e recommend that you repeat this calibration
w hen a temperatur e change gr eater than 10 °C occurs.
Dark Calibration
Dark calibration is used to remove the fixed analog offset from the video path. It is
recommended that you repeat the calibration w hen a temper atur e change gr eater than 10
°C occurs.
To perform dark calibration:
1. Stop all light from entering the camera. (Tip: cover lens with a lens cap.)
2. Verify that output signal level is within range by issuing the command gl or
gla (a valid range is 1-127). If the signal level is too low, adjust the analog offset
(
sao). If the signal level is too high, ensure that no light is entering the camera,
reduce the analog offset or r ed uce the gain l ev el (
sg).
3. Issue the command ccf
. The camera will respond with OK> if no error occurs. Dark
calibration automatically calibrates FPN coefficients and digital offset.
To perform a dark calibration with an analog offset value:
Use the ccf [i] comm and, w her e i is the analog offset DN. When the optional
parameter is provided, this command sets the analog offset first to
i
the FPN coefficients range from 1 to 100 DN for 8-bit data mode, and 4 to 400 DN for
10-
bit data mode for the specified region of interest. If value is left blank, current offset
val ues are used.
4. After the calibration is complete, you can save these setti ngs, and the PRN U
coefficients, to non-volatil e memory so they w i ll be remembered after pow er -down. To
do so, issue the command
wpc.
White Light Calibration
White light calibration is more complex than dark calibration because the camera
attempts to create a flat white image. This calibration corrects PRNU effects as well as
non-uniform lighting and lens vignetting affects.
White light calibration r equires a clean, w hi te reference. The quali ty of thi s reference i s
important for proper calibration. White paper is often not sufficient because the grain in
the white paper will distort the correction. White plastic or white ceramic will lead to
better balancing.
There are several restrictions that must be met in order for the calibration to succeed:
1. The camera is sufficiently sensitive to detect 60 Hz ambient light flicker which may
affect camera performance and calibration results.
2. The light level must be set so that all pixels are betw een 64DN and 254DN , otherw i se a
warning will be sent stating that the camera could not calibrate all pixels to the same
Note: If your
illumination or
white reference
does not
extend the full
field of view of
the camera,
calibration will
not be
successful. The
camera will
send a
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