On Thu, 2007-09-13 at 17:31 -0400, John Kua wrote: > 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.
oh.. thank you a lot for that information. this made a lot things clearer for me. roman > -John > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > On Behalf Of Roman Haefeli > Sent: Thursday, September 13, 2007 5:19 PM > To: [email protected] > 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 > > > > > > > > ___________________________________________________________ > Der fr|he Vogel fdngt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: > http://mail.yahoo.de > ___________________________________________________________ Der frühe Vogel fängt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
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