Dalsa CALIBIR 640 GigE, Руководство пользователя

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Calibir 640 GigE IR Camera User's Manual Features and Configuration Options • 27
Fixed Pattern Noise Correction
All Calibir cameras are factory calibrated to correct for fix pattern noise. The Calibir series
shutterless operation uses the factory calibration to dynamically correct the sensor response across
the entire range of the camera’s ambient operating temperature. However, if required, any
remaining (or newly introduced) fixed pattern noise (FPN) can be corrected by the user.
FPN correction is performed exposing the camera on a scene of uniform temperature and
triggering the FPN calibration feature. After calibration, the FPN calibration coefficients can be
saved to non-volatile camera memory. When enabled, the FPN correction is applied in addition to
shutterless FPN correction.
FPN Compensation Mode = Off
FPN Compensation Mode = Active
Figure 6: FPN Compensation Mode
If a scene of uniform temperature is not used for FPN correction, resulting images will have
artifacts. The following images demontrate the effect of a faulty FPN correction due to the use of a
non-uniform scene.
Non-uniform scene used for FPN calibration
Image with artifacts
Figure 7: Faulty FPN Calibration
The camera supports the use of two FPN correction tables; one for each of the sensor gain settings
(normal or high).
The FPN correction also supports a dynamic adaptive mode that automatically adjusts the
correction progressively with respect to the camera sensor temperature to improve image quality;