Performing Prnu Calibration - Dalsa 4M30 User Manual

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3.7.5 Performing PRNU Calibration

Purpose:
Syntax:
Syntax Elements:
Notes:
Example:
03-032-20044-01
Performs PRNU calibration to a targeted, user defined value and
eliminates the difference in responsivity between the most and least
sensitive pixel creating a uniform response to light. Using this
command, you must provide a calibration target.
Executing these algorithms causes the ssb command to be set to 0
(no background subtraction) and the ssg command to 4096 (unity
digital gain). The pixel coefficients are disabled (epc 0 0) during
the algorithm execution but returned to the state they were prior to
command execution.
cpa x y
x
PRNU calibration algorithm to use:
2 = Calculates the PRNU coefficients using the entered target
value as shown below:
PRNU Coefficient =
i
This algorithm is useful for achieving uniform output across
multiple cameras. It is important that the target value (set with
the next parameter) is set to be greater than 1.2X than the
average signal level when FPN correction is enabled (EPC 1 0).
This is to ensure that full signal swing can be reached for most
pixels.
y
Peak target value in a range from 1 to 1023DN. The target value
must be greater than the current peak output value. If some
pixels are below the target value then the PRNU coefficients for
said pixels will be set to 1X (ie. PRNU coefficients can never be
less than 1X). Similarly the maximum PRNU coefficient is 4X, if
more is needed it will clip at 4X.
Calibrate FPN before calibrating PRNU. If you are not
performing FPN calibration then issue the rpc (reset pixel
coefficients) command and set the sdo (set digital offset) value
so that the output is near zero under dark. FPN calibration is
highly recommended, the use of SDO is not.
The cpa command is not available when the camera is using the
factory calibrated coefficients (csn 0-7). You must select the
user coefficient set (csn 8-15) before you can perform PRNU
calibration. An error message is returned if you attempt to
perform PRNU calibration when using csn 0-7.
cpa 2 700
Falcon 4M Camera Manual
Target
(AVG Pixel Value ) ‐ (FPN +
i
value)
sdo
i
DALSA