Baumer HXC13, Руководство пользователя

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Image Quality 5.6.
Digital Gain 5.6.1.
Command
:D<xxxx>
<xxxx> = 0400 ... 1000
hex
:D<x>
<x> = 0
:D?
Response
--*
* ACK/NAK if acknowledge on
<xxxx>
current value
Description The digital gain can be set from 0400
hex
which is equivalent to
gain 1x to 1000
hex
which is equivalent to gain 4x. Setting the
gain to 0 switches off the correction completely.
Blacklevel 5.6.2.
Command
:k<xx>
<xx> = 32 ... C8
hex
:k?
Response
--*
* ACK/NAK if acknowledge on
<xx>
current value
Description This command adjusts blacklevel. The value 80
hex
is the factory
calibrated default. Increase or decrease this value slightly to
adjust blacklevel.
FPN Correction 5.6.3.
Command
:N<x>
<x> = 0 or 1
:N?
Response
--*
* ACK/NAK if acknowledge on
<x>
current value
Description With this command the column FPN (fixed pattern noise) cor-
rection can be activated or deactivated. At the beginning of
each frame, before visible lines are read out, a fixed voltage is
applied at the columns. These values are read out like real data
and are stored inside the camera. When FPN correction is en-
abled the stored value is subtracted of each pixel. The advan-
tage is a more homogeneous picture but with a limited dynamic.
Notice
IThis noise is not dynamic but fixed (as the name says). That’s a typical effect of a
CMOS sensor. But the fixed pattern makes it easy to eliminate this noise completely.
The camera does only a column correction. If an accurate pixel correction of the full
frame is required this must be done by the framegrabber or in the imaging software. To
do this it’s best to switch off the camera’s FPN correction to get the original dynamic.
Then a complete image of a uniform area must be stored as a reference. This values
must be subtracted for each pixel of the frame and the noise will disappear.
◄ Figure 6
Images captured with-
out (left) and with acti-
vated FPN correction
(right)