Re: CCTV/PC's

["Stuart Grimshaw" <stuart@xxxxxxx>]

OK, here are my thoughts on this subject.

The best way, to me, seems to be to use a single camera, and compare the
current with the previous frame. Someone mentioned that this wouldn't work
if the intruder were stood still, but he isn't going to steal much stood
still either :-)

For outside, ad "zoning" to this setup, ie only look at certain
areas of the
picture, ie the path or the garden, and you eliminate trees moving in the
wind (unless your trees are over your path).

Colour or Black and White? Can't see as it makes much difference really.

The only thing that remains an obstacle is the sun. It might significantly
change the appearence of the picture, ie brightnes as to set off an alarm.
Now to overcome this I propose building a huge disc, which we can attatch
to
a robotic arm, and build it, secretly, into the top of a mountain. We could
extend this arm and block out the sun, so elliminating our problem!

Of course you could always just get it to check 4 or 5 frames in a row...

Also, you wouldn't just be using the camera for intruder detection would
you...

---------------------------------------
Stuart Grimshaw
Schoolsnet LTD             Special
www.schoolsnet.com         Projects
Developer
stuart@xxxxxxx
---------------------------------------

----- Original Message -----
From: <REB.Barnett@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: 08 May 2000 12:32
Subject: RE: [ukha_d] CCTV/PC's


>
>
> > Just 8-bit, monochrome.  I suspect mono makes it much more
> > straightforward,
> > there's probably no significant advantage in using colour for
> > detection.
>
> Just a quick idea that comes to mind... ...and which will probably be
shot
> down almost as quickly... If you use colour, even though light
intensity
> might change over the day, the overall colour make-up of the picture
ought
> not too, unless something is added to the picture - e.g. a burglar
wearing
a
> bright red look-at-me jumper. Thus you could simply sum the amount of
red
> green blue in the picture and look for significant changes in only one
> colour.
>
> This makes the assumption that CCD cameras are not affected by changes
in
> colour balance which I'm guessing is not constant as the sun pops in
and
out
> behind filters (clouds) and sunsets. You could eliminate this using a
second
> camera dedicated to measuring the white balance as a control. It also
> assumes that burglars don't wear camoflauge clothing, but then a more
> conventional movement tracker could be foiled this way too...
>
> Am I spouting rubbish?
>
> Ray.
>
>
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