Dalsa Spyder3 SG-11-01k80-00-R, User Manual

Page: 47 / 93

Spyder3 GigE Vision User’s Manual
DALSA 03-032-20027-02
47
Setting Analog Offset
Sets the analog offset. The analog offset should be set so that it is at least 3 times the rms
noise value at the current gain. DALSA configures the analog offset for the noise at the
maximum specified gain and as a result you should not need to adjust the analog offset.
BlackLevelSelector
Tap selection: All , Tap
1, or
Tap
2
for individual tap selection if you are using the two
tap model.
BlackLevelRaw
Offset value in a range from
0
to
255
DN (12 bit LSB).
To update the analog gain reference:
Sets the current analog gain setting to be the 0dB point. This is useful after tap gain
matching allowing you to change the gain on all taps by the same amount.
GenICam features for updating the analog gain reference:
UpdateGaineReference
Calibrating the Camera to Remove Non-Uniformity
(Flat Field Correction)
Flat Field Correction Overview
Note: The QuickCam software that ships with the Spyder3 GEV camera has a flat field correction
wizard. For easy flat field correction, use the wizard located on the Calibration tab.
This camera has the ability to calculate correction coefficients in order to remove non-
uniformity in the image. This video correction operates on a pixel-by-pixel basis and
implements a two point correction for each pixel. This correction can reduce or eliminate
image distortion caused by the following factors:
•
Fixed Pattern Noise (FPN)
•
Photo Response Non Uniformity (PRNU)
•
Lens and light source non-uniformity
Correction is implemented such that for each pixel:
V
output
=[(V
input
- FPN( pixel ) - digital offset) * PRNU(pixel) – Background Subtract] x System Gain
where V
output
= digital output pixel value
V
input
= digital input pixel value from the CCD
PRNU( pixel) = PRNU correction coefficient for this pixel
FPN( pixel ) = FPN correction coefficient for this pixel
Background Subtract = background subtract value
System Gain = digital gain value
The algorithm is performed in two steps. The fixed offset (FPN) is determined first by
performing a calibration without any light. This calibration determines exactly how much
offset to subtract per pixel in order to obtain flat output when the CCD is not exposed.