Dalsa Piranha ES-80-08k40-00-R User Manual page 58

58
Calibrating Analog Offset
Purpose:
Syntax:
Syntax Elem ents:
N otes:
Exam ple:
Updating the Gain Reference
To update the analog gain reference:
Purpose:
Syntax:
Calibrating the Camera to Remove Non-Uniformity
(Flat Field Correction)
Flat Field Correction Overview
This cam era has the ability to calcu late correction coefficients in ord er to rem ove non -
u niform ity in the im age w hen operating in TDI Mod e. This vid eo correction o perates on a
pixel-by-pixel basis and im plem ents a tw o point correction for each pixel. This correction
can red u ce or elim inate im age d istortion cau sed by the follow ing factors:



Correction is im plem ented su ch that for each pixel:
V =[(V
output input
w here
03-032-20070-02
Instead of m anually setting the analog offset to a specific value,
the cam era can d eterm ine appropriate offset values. This
com m and calculates and averages each tap's pixels w ithin the
ROI and sets the offset to achieve the specified average target
value.
cao t i
t
i


cao 1 50
Sets the current analog gain setting to be the 0d B point. This is
useful after tap gain m atching allow ing you to change the gain on
all taps by the sam e am ount.
ugr
Fixed Pattern N oise (FPN )
Photo Response N on Uniform ity (PRN U)
Lens and light sou rce non-u niform ity
- FPN( pixel ) - digital offset) * PRNU(pixel) – Background Subtract] x System Gain
V
output
V
input
Tap selection. Use 0 for all taps or 1 to num ber of CCD taps
for ind ivid ual tap selection.
Average target value in a range from 1 to 255DN (12 bit
LSB).
Perform analog offset calibration before perform ing FPN and
PRN U coefficients.
To use this com m and , CCD shift d irection should be
controlled internally, either
= d igital ou tpu t pixel valu e
= d igital inpu t pixel valu e from the CCD
Piranha ES-xx User Manual
scd 0 or 1
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