LQ-200CL
27
7.24. Command PGC – Enable Flat-Field Correction (pixel gain)
This command enables (or disables) the “pixel gain” (flat-field) correction function,
which compensates for Pixel Response Non Uniformity (PRNU) for individual pixels.
The algorithm for compensation is different in No-Shutter mode and Shutter-Select mode.
If the operating mode is changed, an adjustment in the selected mode must be made.
The factory default is Shutter-Select mode.
Settings:
0=Off (Default)
1=Factory Setting
2=User area
Associated functions:
Command PGR
Applicable modes:
All
7.25. Command PGR – Pixel Gain Correction and Store in User Area
This command initiates the pixel gain correction function, and stores the settings in the
user area.
Settings:
0= activate automatic process
Associated functions:
Command PGC must be set to 2
Note:
The image sensors must not be saturated when executing this function.
When executing this function, the exposure time and line rate should be the same as
when the camera is operated in the application.
Operating procedure for individual R, G and B channel shading correction:
1.
Before making adjustment,
approximately 30 minutes of warm up is required.
2.
Make sure the output signal is not saturated (<80% of full output is recommended)
3.
Set command PGC=2.
4.
Set command PGR to 0 to initiate shading correction.
5.
If desired, set command SDR to 0 or 1 to activate shading correction to correct the
shading caused by lens or lighting. When the shading correction is performed, the
flat-
field correction must be activated before the shading correction is performed.
Principle of Pixel Gain (flat-field) correction (PRNU correction)
Pixel Response Non-Uniformity is, as the name implies, a non-uniformity of the response
of each individual pixel. This means that for a fixed light level each pixel will have a
slightly different output level (response).
