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Image flickering rapidly
Magna from Canada [4 posts] |
13 year
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Just started working with this software and it looks good so far but my 1st question is probably so obvious I can't see the answer but anyway here it is;
I am using a cheap USB webcam (Microsoft VX-1000) and notice that while the image appears quite stable visually, all forms of analysis produce a series of rapid and extreme variations in the results. It appears as if the image is actually varying in tune with the fluorescent lighting, however I tried lighting the target object with a flashlight and there is not much difference. I saved 60 frames using the "write images" module but they all look the same. Can someone enlighten me?
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Anonymous |
13 year
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Magna,
That's actually normal. Most cameras produce images with a lot of noise that is normally not seen by humans. Only when you process the image and use a filter that highlights this noise does it become apparent. So while you don't 'see' the noise it is actually still there if you look closely.
To prove this, use the Average module
http://www.roborealm.com/help/Average.php
on a still scene and set the number frames to 100 or so. You will then get a very stable and unchanging image when any filter (color etc) is applied to that averaged image. Note that while useful this doesn't help much in situations where the camera moves ....
The trick is to work around this issue ... sometimes adding a mean module filter will help to soften this noise but that depends on your final goal.
STeven.
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