Camera Control and Performing a Scan
Instruction Manual
SK6288VKOC-4L
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Instruction Manual SK6288VKOC-4L © 2018-04 E
a) Using a white homogeneous
background
• Open the
Shading Correction
dialog
(Alt+s).
Use the entries in the left column to obtain
shading correction reference data from a
white homogeneous background.
• Use a homogeneous white object to
acquire the reference data, e.g. a white
sheet of paper.
• Either take a 2-dimensional scan ("Area
Scan Function" [F3] ) or
use a single line signal that was averaged
over a number of single line scans.
• To suppress any influence from the surface
structure, move the imaged object during
the image acquisition.
• Input the scale range:
Minimum in %:
intensity values lower than
“Minimum” will not be changed.
A typical appropriate value is 10% of the full
intensity range, i.e. 26 (= 10% · 255) for an 8-bit
intensity scale.
Maximum in %:
target value for scaling
A typical appropriate value is 90% of the full
intensity range. The result will be a homogeneous
line at 230 (= 90% 255) for an 8-bit intensity scale.
• Click on button
New Reference
• Click on
Save SCM to Flash
to save the SCM
reference signal in the flash memory of the camera
b) Analytic compensation of
natural lens vignetting
• Open the
Shading Correction
dialog (Alt+s).
Use the entries in the middle column to calculate
the reference data based on the imaging setup.
• Enter the parameters focal length (FL), sensor
length (SL) and field of view (FOV) according to your
setup.
The implemented algorithm will compensate the
natural lens vignetting.
• Click on
Save SCM to Flash
to save the SCM
reference signal in the flash memory of the camera
Step 2: Obtaining the Shading Correction Data
The shading correction refrence data that is stored in the shading correction memory (SCM) can be obtained in
two ways:
Shading Correction dialog
Parameters for correction of natural lens vignetting:
FL
= Focal Length of the lens in mm
SL
= Sensor Length in mm
FOV
= Field Of View in mm
Power-down and Power-up Behaviour
The shading correction memory (SCM) buffer is a volatile
memory. Its content is lost on power-off.
Once the reference signal is copied from the SCM to the
camera flash memory, it will persist even after a power-
down. On a re-start, this data will be restored automatically
from the flash memory back into the SCM.
The shading correction status on shutting down - active or
not active - will be retained and automatically restored on
power-up.
Color line signal
with separated
RGB curves after
Gain Adjustment
and Shading
Correction
Save SCM to Flash
Save the SCM reference
signal in the flash memory of
the camera
ON
Activate Shading Correction
with the reference signal that
is stored in the SCM.
OFF
Switch off Shading Correction.
This does not affect the
content of the camera SCM
buffer or the camera flash
memory.
Save SCM to File
The SCM reference signal will
be stored in a file.
Load File to SCM
A stored reference signal will
be loaded into the SCM of the
camera. If the load process
completes then the Shading
Correction is active.