Piranha HS-S0-06K Camera User Manual
03-032-20213-01
Teledyne DALSA
32
PRNU Correction
Performing PRNU to a user entered value
Pu rp ose:
N ote: CPA 5 or 6
shou ld be u sed .
CPA 2 and 4 are
available, bu t
u sing them m ay
cau se you r cam era
to p erform
contrary to its
sp ecifications.
Perform s PRN U calibration to u ser entered valu e and elim inates the
d ifference in resp onsivity betw een the m ost and the least sensitive
p ixel creating a u niform resp onse to light. Using this com m and , you
m u st p rovid e a calibration target.
Execu ting these algorithm s cau ses the
ssb
com m and to be set to 0 (no
backgrou nd su btraction), the
ssg
com m and to 0 (u nity d igital gain),
and the
sab
com m and to 0 (no backgrou nd ad d ition). The p ixel
coefficients are d isabled (ep c 0 0) d u ring the algorithm execu tion bu t
retu rned to the state they w ere p rior to com m and execu tion.
Ad d itionally w hen CPA 5/ 6 are u sed , th e d igital gains w ill be
au tom atically ad ju sted for op tim al p erform ance w hen calcu lating
p ixel coefficients. It is exp ected that after u sing CPA 5/ 6 that you r
gains w ill be set to a new valu e.
Syntax:
cpa i i
Syntax Elem ents:
i
PRN U calibration algorithm to u se:
5
= Calcu lates the PRN U coefficients and Digital gains u sing the
entered target valu e as show n below :
Target valu e (14 bits) in range from 4096 to 16220DN
For exam p le, if the cam era is in 8 bit m od e and the target is to be
200DN , u se (200x64) = 12800 (14 bit equ ivalent) as target valu e.
The calcu lation is p erform ed for all sensor p ixels bu t w arnings
are only ap p lied to p ixels in the region of interest. This algorithm
is u sefu l for achieving u niform ou tp u t across m u ltip le cam eras.
It is im p ortant to note that the target valu e (set w ith the next
p aram eter) d oes not need to be equ al of higher to the highest
p ixel across all cam eras. Since the cp a 5 fu nction now controls
gain, negative gain valu es m ay also be set au tom atically. The
id eal resu lt of CPA 5 is that the PRN U coefficients and the
cam era gain are setu p au tom atically.
6
= Calcu lates the PRN U coefficient and the Digital gains in the
sam e w ay as
cpa 5
w ith the excep tion that this com m and only
calcu lates PRN U for p ixels w ithin the cu rrent Region of Interest
(ROI).
i
Peak target valu e in a range from 4096 to 16220 DN .
N otes:
Calibrate FPN before calibrating PRN U. If you are not
p erform ing FPN calibration then issu e the
rpc
(reset p ixel
coefficients) com m and .
CPA 2 and CPA 4 fu nctions are still available for u se in the
cam era, bu t Teled yne DALSA d oes not recom m end their u se
and w ill not gu arantee any cam era sp ecifications. The im p rop er
u se of CPA 2/ 4 m ay cau se the cam era to exceed its d esigned
p erform ance criteria.
CPA 2/ 4 w ill only calcu late a PRN U coefficient and w ill not
ad ju st gain.
