F'up not set because I don't really know where this goes.
I want to put a picture of a pregnant horse on a website using a
Linksys WVC200 webcam.
I've played around just a little with webcams and IR LEDs and IMHO the
best way to figure out if a particular webcam will work is to try it and
see. If you guess right the first or second time it can be an
inexpensive way to get an IR camera; if not you end up paying a lot of
shipping charges or spending a lot of time at the store doing exchanges.
If you move up into cameras that are sold as security cameras,
especially black-and-white ones that are sold for low-light use, IMHO
your luck gets a lot better. On the other hand, these cameras are more
expensive, and they usually have just a composite video output, so you
will need a video capture card of some kind. If you can tolerate lower-
quality images, run the security camera to a standard TV monitor, and
point a webcam at the TV monitor. (If you are writing a grant, call
this a "single-conversion superheterodyne lightwave reciever" instead.
Sounds much more fundable than "pointing a webcam at a TV set".
)
Another option might be a "board" camera. These don't have nice
packages but can be inexpensive.
http://gargravarr.cc.utexas.edu/owl/2006/box/ is an example (with specs
for the camera used) of using an IR camera and IR LEDs to observe
animals, albeit in a much smaller space than a horse stall. Again,
these will probably only have a composite video output, so you'll need
extra hardware to get the video signal into the computer.
The vet says it's not a good idea to keep the 10'x20' stall lit and
the horse awake all night.
Something to check is whether horses can see IR or not.
http://www.journalofvision.org/1/2/2/Carroll-2001-jov-1-2-2.pdf (linked
from
http://www.journalofvision.org/1/2/2/ ) suggests they're not too
good at it, so using IR for light that's "invisible" to a horse may be
OK.
Amazon sells $50 low-power IR LED arrays, with mixed reviews.
If you don't mind doing the work, you can probably make something just
as good with a fistful of IR LEDs and a power supply from Mouser or
Digi-Key. It might also be useful to spread the LEDs around the stall a
bit, instead of having them all in one place.
Would a 100 W incandescent bulb run at low voltage work as well?
This is what was used in the paper linked to above. They had a fancy
tunable filter, though.
If you can accept a succession of still images, rather than video, using
a digital still camera might be another way to go. If you can find some
cameras old enough to be cheap, you might use more than one to get
different angles or shorter times between pictures. (This will be
easier to do with USB cameras but is probably possible with older
cameras that only had a serial port.) Googling finds
http://www.wrotniak.net/photo/infrared/ on using digital still cameras
in IR and there are probably many other sites.
Of course, all this stuff needs to get installed up high or behind glass
or otherwise protected from the horse. She might get annoyed and smash
the camera if she finds out she's not getting a cut of the click-throughs.
Matt Roberds
