Piranha HS-xx RoHS User Manual
03-032-20013-03
Teledyne DALSA
54
m u ltip liers and are d efined to be of a valu e greater than or equ al to 1. This ensu res
that all p ixels w ill satu rate together. When u sing PRN U correction, it is im p ortant
that the A/ D offset and Fixed Pattern N oise (FPN ) or p er p ixel offsets are su btracted
p rior to the m u ltip lication by the PRN U coefficient. The su btraction of these 2
com p onents ensu re that the vid eo su p p lied to the PRN U m u ltip lier is nom inally zero
and zero m u ltip lied by anything is still zero resu lting in no PRN U coefficient ind u ced
FPN . If the offset is not su btracted from the vid eo then there w ill be artifacts in the
vid eo at low light cau sed by the m u ltip lication of the offset valu e by the PRN U
coefficients.
4.
Backgrou nd su btract (
ssb
com m and ) and system (d igital) gain (
ssg
com m and ) are
u sed to increase im age contrast after FPN and PRN U calibration. It is u sefu l for
system s that p rocess 8-bit d ata bu t w ant to take ad vantage of the cam era’s 12-bit
d igital p rocessing chain. For exam p le, if you find that you r im age is consistently
betw een 128 and 255DN (8-bit), you can su btract off 128 (
ssb 2048
) and then
m u ltip ly by 2 (
ssg 0 8192
) to get an ou tp u t range from 0 to 255.
The follow ing sections are organized as follow s:
1.
Section Analog Signal Processing p rovid es a d etailed d escrip tion of all analog
p rocessing chain com m and s.
2.
Section Calibrating the Cam era to Rem ove N on -Uniform ity (Flat Field
Correction) p rovid es an overview of how to p erform flat field calibration.
3.
Section Digital Signal Processing p rovid es a d etailed d escrip tion of all d igital
p rocessing chain com m and s.
Analog Signal Processing: Setting Analog Gain and
Offset
All analog signal p rocessing chain com m and s shou ld be p erform ed p rior to FPN and
PRN U calibration and p rior to d igital signal p rocessing com m and s.
Setting Analog Gain
Pu rp ose:
Sets the camera’s analog gain value. Analog gain is multiplied by
the analog signal to increase the signal strength before the A/ D
conversion. It is u sed to take ad vantage of the fu ll d ynam ic range
of the A/ D converter.
Syntax:
sag
t f
Syntax Elem ents:
t
Tap selection. Use
0
for all tap s or
1
to nu m ber of CCD tap s
for ind ivid u al tap selection.
f
Gain valu e in a range from
–
10
to
+10
d B.
Exam p le:
sag 0 5.2
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