Subject:
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Re: Vision Command for newbies
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 17 Sep 2003 17:53:35 GMT
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Viewed:
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696 times
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"Duq" <lugnetpost@skipthisbit.duq.tmfweb.nl> wrote:
> The vision command's been sitting on the shelf for some time, so I thought
> I'd try and use it. Problem is, I'm quite disappointed with the picture
> quality. I wonder if anything is wrong with the camera.
> What kind of quality should I expect? What I get now is all speckled, I
> can't get a proper focus, and at least indoors everything is in shades of
> orange.
Webcams, especially ones with tiny lenses like the Lego cam, don't
like incandescent light (regular filament bulbs). They're a bit better
(less orange) with striplights or energy saving bulbs. They're much
better with sunlight.
The speckles are thermal noise on the CCD. You need to improve the
signal to noise ratio to get rid of them. You can either reduce noise
by cooling the cam down (not easy) or increase the signal by making it
brighter.
You could also buy a better lens. I found the c-mount lenses I use on
my wireless cams fit the Lego cam and make a huge improvement, but you
have to take the cam apart and the rubber focussing ring (attached to
the lens) almost certainly wouldn't fit the new lens. I chopped some
plastic off my focussing ring so I can unscrew it and the lens and
replace it without dismantling the whole cam.
My lenses cost about 10ukp (~15euros or dollars) from Maplin here in
the UK, but they don't seem to have the range they used to. Make sure
the lenses have good IR filtration or in incandescent light reds will
glow in freaky colours. I just replaced my bulbs with energy saving
ones and ignored that consideration :)
Tim
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Message is in Reply To:
 | | Vision Command for newbies
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| The vision command's been sitting on the shelf for some time, so I thought I'd try and use it. Problem is, I'm quite disappointed with the picture quality. I wonder if anything is wrong with the camera. What kind of quality should I expect? What I (...) (21 years ago, 16-Sep-03, to lugnet.robotics)
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