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5.5.3 Storing the calibration in permanent memory
After running the calibration procedure (see Section 5.5.2) the calibration values are stored in
RAM. When the camera is turned off, their values are lost.
To prevent this, the calibration values must be stored in flash memory. This can be done by
clicking on the property BadPixelCorrection_SaveToFlash (in category BadPixelCorrection). Wait
until the command has been finished.
Storing the calibration in permanent memory overwrites the factory calibration.
5.6 Column FPN Correction
Due to the readout structure of the image sensors there is a column-wise fixed pattern noise
(FPN). The Column FPN Correction (ColCorrection) adds or subtracts a fixed value to a column.
These values are obtained by a calibration process. The ColCorrection of the camera was
calibrated at Photonfocus production facility.
5.6.1 Enable / Disable the Column FPN Correction
The Column FPN Correction can be enabled or disabled with the property ColCorrection_Enable
(in category Correction/ColCorrection). By default the correction is enabled.
5.6.2 Calibration of the Column FPN Correction
The Column FPN Correction of the camera is correctly calibrated at Photonfocus production
facility. Although a new calibration is normally not required, you can recalibrate the Column
FPN Correction with the following instructions:
1.
Setup the camera to the mode where it will be usually used. (Exposure time, ...). The
width and height should be set to its maximal value.
If different exposure times will be used, calibrate the camera under the longest
exposure time.
2.
Put the camera in free-running mode by setting the property TriggerMode to Off.
3.
Start grabbing of the camera by clicking on the Play button.
4.
Wait until the camera has achieved working temperature.
5.
Close the lens of the camera or put a cap on the lens. The calibration requires an uniform
dark image. The black level offset should be set so that all pixels (except defect pixels)
have values above 0.
6.
Set the visibility of the Device Control window of the PF_GEVPlayer to Expert.
7.
Run the command ColCorrection_CalibrateBlack (category ColCorrection) by clicking on
the corresponding button. The camera transmits a test image during calibration.
8.
Run the command ColCorrection_Update by clicking on the corresponding button. Read the
ColCorrection_Busy value which should be 0 after the calibration has finished. Repeat this
step if its value is not 0. If the ColCorrection_Busy value doesn't show 0 after various tries,
check if the camera receive triggers or set the TriggerMode of the camera to Off.
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5.6 Column FPN Correction
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