Roman,
I recently went through this problem. It seems that using setpwc to disable
AGC is pointless, because the next time the camera is accessed, as far as I
can tell, it defaults back to AGC on. This, however, is not a pwc problem,
nor is it really a setpwc problem. Because the AGC setting resets every time
you open the camera for access, you have to disable AGC, set your desired
gain AND capture the images you want in one session.
In other words, the program you use to capture your images has to set the
gain itself.
-John
-----Original Message-----
From:
On Behalf Of Roman Haefeli
Sent: Thursday, September 13, 2007 5:19 PM
To:
Subject: [pwc] automatic gain control
hello
i plan to use my SPC 900NC for an artistic project. therefor i want to
make a comparison between a buffered background image and the realtime
image in order to remove the background of the image.
however, this only works, if i manage to keep the gain stable. according
to 'setpwc -h', i am supposed to set a value for automatic gain control
by using "setpwc -g <0-65535>". actually, i am not quite sure what
"setting the automatic gain control" means. i mean, why is there a user
settings, when it is done automatically anyway?
i had the impression, that this setting doesn't affect anything or it
gets overwritten instantly by the automatic gain control. i found out,
that whenever i access the cam through setpwc (or mplayer or
whatsoever), the gain is adapted.
doing 'setpwc -p', while pointing the cam towards a light, i get:
Automatic gain control: -2502
doing the same while pointing the cam into the dark, i get:
Automatic gain control: -25815
to sum it up:
the option '-g' doesn't show any effect at all.
the values seem to be in the negative range, not in the range 0-65535,
as mentioned in the help.
is this a bug? (of pwc or setpwc?)
is there some way to get rid of automatic gain control?
is this something the driver does or the camera itself?
i am using:
pwc-10.0.12-rc1
setpwc v1.1
thanks in advance
roman
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