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Motion detection question
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By:
PeterSa
Rank:
Newbie
Topics:
3
From:
n/a
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Added:
03/01/2009 - 07:05 PM
I'm using USB20 PC Camera-268-1.
When I use local save, images are saved to disk with the stated interval between images.
When I enable motion detection with a trigger threshold of 1 ( max sensitivity), this does not seem to be enough to trigger when an object moves across the field of view. I can see that the "current level" regularly exceeds 1, but this does not trigger a save of the image. If I block off part of the image, I can trigger a save but this is extreme and I want the save to be triggered when a person or animal moves into the field of view and I cannot see how to set this up to be this sensitive.
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By:
sse
Rank:
Forum Addict
Topics:
73
From:
n/a
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Added:
03/02/2009 - 10:48 AM
How are the light conditions? Motion detection does not work well when the contrast is low.
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By:
MelvinG
Rank:
Magna Cum Laude
Topics:
661
From:
Los Angeles, USA
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Added:
03/02/2009 - 11:00 AM
Have you tested this in a realistic setup - e.g. with the movement happening at least 1 - 2 meters away from the lens of the cam? I just tested here with a Pro-9000 USB cam to see if I could duplicate the problem. Waving my hand madly up & down at ~300cm from the lens, motion level was never >2. But doing the same hand motion at 1.5m away from the lens worked fine - motion level went up to about 45.
I'm not 100% sure I understand why it acts like this, but it does on my setup.
For this kind of testing it is often useful to enable "Motion Sound" so that you know exactly when the saves are triggered. When you have your settings perfect turn off the sound...
EDITED to add: when waving my hand close to the lens contrast is poor because the background of the scene is a white wall and my hand is fairly white. This may explain some things.
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By:
PeterSa
Rank:
Newbie
Topics:
3
From:
n/a
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Added:
03/02/2009 - 09:23 PM
Thanks for the suggestions.
I set the threshold to 1.
I pointed the camera at the garden and went out and walked around to see if it would trigger on a real scene. It was a dull day, so perhaps there was a problem, but the image looked OK on the screen and I guess my body represented about 1/100th of the pixels.
Back indoors, I switched on the motion sound and that worked fine if I do something like hold my hand across to block a large part of the field of view for more than a second.
If I move a pencil just into the field of view, I can see the motion level rise to 20 or more but this is not enough to cause a trigger.
I wonder if there is some time constant involved so that if the motion level returns to zero before the next sample, it misses the instantaneous rise?
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By:
JoergR
Rank:
Frequent User
Topics:
34
From:
Germany
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Added:
03/13/2009 - 05:32 PM
I also was testing this. I saw that even moving trees caused a motion detection when set to default, so I unchecked auto-trigger and set it to 9.
By this I get a detection when I walk 300cm away across the viewing angle. I still must find out the settings to freeze some little animals...
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By:
sse
Rank:
Forum Addict
Topics:
73
From:
n/a
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Added:
03/13/2009 - 05:45 PM
Auto-trigger calculates the average motion level and triggers when something causes the motion level to raise significantly above average.
It has been developed to cope with cameras which create noise in dark environments. A fixed level does not work for cameras which are on 24/7 and have a noisy picture in darkness.
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By:
PeterSa
Rank:
Newbie
Topics:
3
From:
n/a
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Added:
03/14/2009 - 06:55 PM
I have seen motion detection working before. I have seen the problem with trees moving and triggering but right now nothing is working with motion detection. With auto-trigger or without, if I going out in the garden and move around I cannot get it to trigger and save. I tried putting my logitech camera back (lower resolution) but that was even worse didn't give any motion detection level at all, even though I could see the image and put my hand over the camera.
It's as if the sensitivity to movement has decreased somehow.
I wonder it is worth de-installing and re-installing in case some parameter is not correct?
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By:
sse
Rank:
Forum Addict
Topics:
73
From:
n/a
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Added:
03/14/2009 - 07:03 PM
Peter,
deinstallation and reinstallation will not change your configuration.
In order to remove your configuration, go to the configuration folder and remove or rename the camera config folder.
you may also want to try the latest (beta) release, available from Issues which includes optionally an improved motion detection algorithm.
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By:
PeterSt
Rank:
Newbie
Topics:
1
From:
n/a
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Added:
03/15/2009 - 07:17 PM
I couldn't find the configuration folder.
However, I tried the beta release and I can now moved around in the garden and it noticed the movement in the low contrast mode. I'll continue experimenting now. Thanks very much for the help.
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