Dalsa Piranha 2 Series, Руководство пользователя

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37 Piranha 2 User’s Manual
03-032-00493-14 Teledyne DALSA
To perform dark calibration:
1. Stop all light from entering the cam era. (Tip : cover len s w ith a lens cap .)
2. Verify that ou tp u t sign al level is w ithin range by issu ing the com m and
gl
or
gla
(a valid range is 1-127). If the signal level is too low , ad ju st the analog offset
(
sao )
. If the signal level is too high, ensu re that no light is entering the cam era,
red u ce the analog offset or red u ce the gain level (
sg )
.
3. Issu e the com m and
ccf
. The cam era w ill resp ond w ith OK> if no error occu rs. Dark
calibration au tom atically calibrates FPN coefficients an d d igital offset.
To perform a dark calibration w ith an analog offset value:
Use the
ccf
[
i ]
com m an d , w here
i
is the analog offset DN . When the op tional
p aram eter is p rovid ed , this com m and sets the an alog offset first to
i
before calcu lating
the FPN coefficients range from 1 to 100DN for 8-bit d ata m od e, and 4 to 400DN for
10-bit d ata m od e for the sp ecified region of interest. If valu e is left blank, cu rrent offset
valu es are u sed .
4. After the calibration is com p lete, you can save these settin gs, and the PRN U
coefficients, to non -volatile m em ory so they w ill be rem em bered after p ow er -d ow n.
To d o so, issu e the com m and
wpc
.
White Light Calibration
White light calibration is m ore com p lex than d ark calibration becau se the cam era
attem p ts to create a flat w hite im age. This calibration corrects PRN U effects as w ell as
non-u niform lighting an d lens vignetting affects.
White light calibration requ ires a clean, w hite reference. The qu ality of this reference is
im p ortant for p rop er calibration. White p ap er is often not su fficient becau se the grain in
the w hite p ap er w ill d istort the correction. White p lastic or w hite ceram ic w ill lead to
better balancing.
There are several restriction s that m u st be m et in ord er for the calibration to su cceed :
1. The cam era is su fficiently sensitive to d etect 60 H z am bient light flicker w hich m ay
affect cam era p erform ance and calibration resu lts.
2. The light level m u st be set so that all p ixels are betw een 64DN an d 254DN , otherw ise
a w arning w ill be sent statin g that the cam era cou ld n ot calibra te all p ixels to the sam e
level. Use the
gl
com m and to d eterm ine inp u t level. If the signal level is too low or
too high, ad ju st an alog gain u sing the com m and
sg
.
These restriction s are all tested w ithin the calibration algorithm and the cam era w ill
rep ort an inform al m essage cod e if any of these con d ition s cou ld not be m et.
Note: If your
illumination or white
reference does not
extend the full field of
view of the camera,
calibration will not be
successful. The camera
will send a warning.
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