4
To make DSNU / PRNU correction, two pictures should be taken. For DSNU a reference image has
to be recorded in dark, with lens closed (offset should be boosted) or fully removed from the camera
and covered with a solid cap. To calibrate for PRNU a reference image has to be recorded with a
uniform illumination of around 40%. These two separate steps in the flat field correction are therefore
referred to as dark field calibration and bright field calibration, respectively.
Figure 3 : JetCam Camera side view w/o lens
3.1
Dark field calibration process
The dark field correction is the easiest one to calibrate. It only requires a reference image to be
recorded without illumination on the image sensor.
Follow this steps to perform dark field calibration process:
1.
For dark field calibration, the light should be blocked from the sensor. This can be achieved by
removing the lens and covering the sensor with a solid cap or closing the lens with a cap
2.
Set the “Field Calibration Mode” to “Dark” (1)
3.
Start camera’s stream either in free run or by applying an external trigger
4.
Initiate the selected calibration with “Field Calibration Start” command Execute (2)
5.
Stop camera’s stream
6.
Enable the Dark filed correction (3)
7.
Start camera’s stream either in free run or by applying an external trigger
NOTE that Dark field calibration should be performed before Flat field.
3
Using the DSNU and PRNU corrections
