Re: Ant's homebrew motion detector

[James Derrick <james@xxxxxxx>]

On Tue, 14 Nov 2000 11:04:51 +0000, you wrote:

>Is anybody actually interested in this? Or should I shut the hell up?
Add one to the ballot for interested parties!

I hacked together a basic motion detector/ image capture system from
Video4Linux drivers and libbgrab-2.1f (Linux video library with a
motion detection example). It's nowhere near as clever as your method
as it simply does a pixel-by-pixel diff of brightness between frames,
masks areas and compares to a threshold.=20

This runs at about 0.6 load on a 433 Celeron and RedHat 6.2.

I guess this is temporal differencing with masks and thresholds.=20

This works OK until sunlight reflects into my cheap IR-sensitive mono
CCD camera and blinds it. Maplin have a colour CCD camera in the sale
for =A340, an example of which is now sitting on my workbench. Lets hope
is better at seeing in sunlight _and_ compact fluorescent porch light!

Your images are interesting (not least for the test images!) when the
temporal difference is compared with the detected motion. Temporal
noise (changing lighting?) is filtered out nicely, but the detected
motion seems to be rather insensitive. I take it that the background
'statistical model' is something like a weighted mean of past temporal
diffs?

James
---
James Derrick    james@xxxxxxx, Cramlington, Near Newcastle, Eng=
land
Forwarding Service: jderrick@xxxxxxx
Beyond the Horizon of the place we lived when we were youn=
g,
In a World of Magnets and Miracles. Pink Floyd.

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