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Shad-o-Scan 3001/4501 Detector
Teledyne DALSA
store three gain maps for different exposure situations in combination with two dark
maps for use with different integration times.
FFC Gain Map Status
and
FFC Dark Map Status
indicate if a valid map has been selected.
FFC Processing
will show
Active
when both a valid FFC Dark and FFC Gain map is in use.
The dark reference map can be updated using actual dark images from the detector, for
example when capturing images with long integration time. To do so, set the
FFC Mode
to
New Dark
and perform an image
Snap
. The detector will output the requested image to
the host application. In detector volatile memory, the captured image will be added to the
current dark reference map using the
FFC New Dark Weight
value. The dark reference
map stored in the detector’s non
-volatile memory, which is loaded on power-up, is not
automatically updated. With
DarkMap Save To Flash
you may store this new dark
reference to the Customer Dark map.
FFC NewDark Status
indicates when the save
operation is finished.
Example 1: to update the actual dark reference map, for example to correct for changing
detector temperature conditions, set
FFC New Dark Weight
to 20 and
Snap
a few dark
images every 5-10 minutes.
Example 2: to create a fully new dark reference map, for example when the integration
time is significantly changed, first set
FFC New Dark Weight
to 100 and
Snap
a dark image
to overwrite the old dark reference map. Then set
FFC New Dark Weight
to 10 and
Snap
at
least 32 dark images to average out the random noise in the dark image.
Ensure that the detector is not exposed to X-rays during capturing of new dark images, as this
will significantly impact the usability of the updated dark reference map and the quality of the
FFC operation.
Disable DPC while creating new or updated dark and gain reference maps for FFC. This will
ensure that FFC will deliver optimal results.
Volatile memory space of the detector is limited. This may cause a Gain/Dark map selection
issue with map 7 when all customer maps (map 0
–
map 7) are used for Full Resolution modes.
After changing the
Factory/Customer Map Select
mode, the detector needs to transfer the
selected Factory/Customer Maps to volatile memory. When this process is finished, the
detector’s network connection needs to be re
-established.
FFC and/or DPC processing will be disabled in case not all reference maps for the selected mode
are available or the wrong map is selected in
Manual Map Select
mode. The
FFC Processing
and/or
DPC Processing
field will show
Not Active.
Defect Maps
Introduction
Defect pixel reference maps are stored in detector non-volatile memory. These maps
contain information on the position of defective (or deviating) pixels, required for Defect
Pixel Correction (DPC). These maps are detector-specific, and are generated during
Teledyne DALSA factory calibration.
