Dalsa Linea ML ML-FM-16K15A, Руководство пользователя, Страница: 42 / 83

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Camera Performance and Features
One way to minimize this effect is to have the white target in motion during the calibration process.
This has the result of averaging out any dirt or texture present. If this is not possible, the camera
has a feature where a flat field calibration filter can be applied while generating the flat field
correction coefficients—which can minimize the effects of dirt. Note that this filter is only capable of
compensating for small, occasional contaminants. It will not overcome large features in a target’s
texture. This filter is a 33 pixel moving average.
Flat Field Calibration Regions of Interest
See the section Flat Field Category in Appendix A for GenICam features associated with this section
and how to use them
Related Features: ROI Offset X, ROI Width
There are occasions when the camera’s field of view includes areas that are beyond the material to
be inspected.
This may occur when cameras image off the edge of a panel or web or when an inspection system
is imaging multiple lanes of material. The edge of the material or area between lanes may not be
illuminated in the same way as the areas of inspection and, therefore, will cause problems with a
flat field calibration.
The camera can accommodate these “no inspection zones” by defining a Region of Interest (ROI)
where flat field calibration is performed. Image data outside the ROI is ignored by the flat field
calibration algorithm. The ROI is selected by the user and with the pixel boundaries defined by the
pixel start address and pixel width and then followed by initiating flat field calibration for that
region. Once set, the next ROI can be defined and flat field calibrated.
TDI Stage Selections and Full Well
See the section Camera Control Category in Appendix A for GenICam features associated with this
section and how to use them
Relevant Features: sensorTDIMode, sensorTDIStagesSelection, sensorFullWellMode
The camera’s sensor has 3 high-responsivity lines. These line scan be summed to further increase
the responsivity. The TDI Stage Selection feature with values of 1, 2, or 3 lines allows the user to
increase the responsivity proportionally but at the sacrifice of the maximum line rate.
Lines Summed / Averaged Maximum Line Rate, 8 bit
1 300 kHz
2 150 kHz
3 100 kHz
Along with a reduction in line rate, other features need to be considered when using the stage
selection feature. SensorScanDirection and sensorLineSpatialCorrection need to be set correctly if
summing 2 or more lines using the TDI stage selection control. If only using one line,
sensorScanDirection and sensorLineSpatialCorrection are not relevant.
SensorTDIMode allows the user to either sum the lines or average the lines. This allows the user to
optimize the responsivity/full well or the signal to noise ratio.