Piranhs HS-xx Detailed Getting Started Guide
16
DALSA Corp.
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ignored. It is recommended that you set the region a few pixels inside the
actual useable image.
17.
Repeat the
ccg 1 0 i
command. You will see tap mismatch but the PRNU
algorithm (
ccp
command which is performed later) will eliminate the tap
mismatch.
18.
Reset the pixel coefficients to ensure that FPN values are set to zero by
entering the
rpc
command.
19.
For best accuracy, set the number of samples to use in the coefficient
calculation algorithm to its maximum using the command
css 1024
.
20.
After having adjusted the gains, selected the number of stages, and warmed
up the camera with the correct line rate, you can now perform FPN
correction. (Skip to step 22 if you are unable to put a lens cover onto the
camera to make the image dark.) To begin, put a lens cover on the camera
and enter the
ccf
command. The camera calculates the FPN values and
reports a warning if more than 1% of the FPN coefficients were clipped to
the maximum value or if there was too much random noise. The digital
offset value is also calculated causing the A/D offset to be subtracted from
the output signal.
If you receive a warning during FPN correction:
•
Ensure the lens is covered
•
Increase the analog offset using the
sao 0 offset
value
command.
Repeat the
ccf
command if the offset is changed.
21.
Enter the command
wfc i 1
to save the FPN coefficients.
22.
If you performed FPN correction, the output video should be near zero and
you can skip to the next step. If not, the value should be near 100LSB in 12
bit. Enter the command
sdo 0 100
to subtract offset.
23.
Remove the lens cover and enter the command
ccp
to perform PRNU
correction. The camera calculates the PRNU coefficients for all pixels using
the peak pixel found in the ROI and reports statistics for the ROI. You
receive a warning if more than 1% of the coefficients are clipped or there
were too many clipped values in the raw data.
If you receive a “W08: Greater than 1% of coefficients have been clipped>”
message during PRNU correction:
•
Check that your region of interest is correct
•
Check that your light source uniformity is better than 50%
If you receive a “W07: Coefficient may be inaccurate A/D clipping has
occurred>”
•
Reduce the camera gain to avoid clipping. Repeat the
ccp
command if
you adjust the gain.
24.
Enter the command
wpc i 1
to save the coefficients.
25.
Turn on the coefficients by entering the command
epc 1 1
. You should see
a flat line approximately equal to the peak uncorrected output.
26.
If you will be operating the camera in the reverse direction, enter the
command
scd 1
to change to reverse direction and repeat steps 7 to 25.
27.
If you will be operating the camera using external direction control, test the
external control by entering the command
scd 2
, otherwise skip to step 32.
28.
Have your system send the forward direction signal on CC3 (high).
