Linea HS Series Camera User's Manual
Camera Performance and Features
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Those areas of the image where high roll-off is present will show higher noise levels after flat field
calibration due to the higher gain values of the correction coefficients. Flat field calibration can only
compensate for up to an 8:1 variation. If the variation exceeds 8:1 then the line profile after
calibration will include pixels that are below the un-calibrated peak level.
Note:
The Linea camera has many different modes of operation. It is strongly
recommended that the camera be flat fielded for that mode of operation that is intended
including direction of scan
Saving & Loading a PRNU Set Only
See the Flat Field Category in Appendix A for GenICam features associated with this section and
how to use them.
Related Features:
flatfieldCorrectionCurrentActiveSet
A user set
includes all the “settings” (
for example, gain, line rate), FPN (Fixed Pattern Noise) and
PRNU (Photo Response Non-Uniformity) coefficients and a LUT. These three features let you
save/load just the PRNU coefficients. Loading a complete user set takes approximately 1 second
while loading only the user PRNU coefficients takes less than 200 milliseconds.
Use the User PRNU Set Selector parameter
to select the set you want to save or load. There are 17
sets available
—
16 user and 1 factory.
The
Factory Set
is read-only and contains all ones. Loading the Factory Set is a good way to clear
the user PRNU.
Save the current user PRNU coefficients using the
“Save User PRNU Set”
command. Load the user
PRNU coefficients from the set specified using the
“User PRNU Set Selector” and
the
“Load User
PRNU Set”
command features.
Setting Custom Flat Field Coefficients
Flat Field (PRNU) coefficients can be custom modified and uploaded to the camera. They can also
be downloaded from the camera.
To upload or download coefficients, use File
Access Control Category > Upload / Download File >
Settings
and then select
Miscellaneous > Current PRNU
to download / upload a file.
The PRNU coefficients are used by the camera as soon as they are uploaded. To avoid loss at
power up or while changing row settings, the uploaded coefficients should be saved to one of the
available user sets.