Re: Webcam for dog training
- From: Paul <nospam@xxxxxxxxxx>
- Date: Thu, 06 Dec 2007 05:47:43 -0500
John D. wrote:
Hi,
I'm looking for a webcam to record a dogs behaviour (as part of
staying-home-alone training). I have no experience with webcams, so I'm
hoping for hints or recommendations.
The most important thing would be enough frames per second to actually
see how the dog is moving and behaving. For example, it is important to
see if he's jerking his head around nervously, or if he's just looking
around. (It's a medium-to-large adult dog.)
The area to be filmed (around his sleeping place) would be about 3x3
meters in a 4x4 room. I would try to attach the camera up in a corner of
the room, but I guess it would still need a rather wide field-of-view?
I have no idea about focus options. Do I need auto-focus for this? Or
does it not matter here? I'd say the distance range is about 1,5-3,5
meters. Light conditions in the room are average (window+artificial).
For the recording, the software should be able to record with sound. It
would be ok if there's no microphone included if you can use an external
one. A "record on motion" feature would be very helpful. Is there any
software that has a "record on sound" feature, too?
I've played with a couple CCTV cameras, with a couple different
C mount lenses. My experience is, it is very hard to frame shots
properly, or to get them lit properly. And these weren't the
cheapest cameras either. Camera specs are rather meaningless,
is the lesson I learned from that.
The camcorders you see at your local big box store for sale, have
excellent characteristics, by comparison to the kinds of stuff they
sell for computers. With cheap "toy" cameras, expect to need halogen
lighting, to get rid of the "blotchy" noise pattern from the sensor.
I found that the gear I bought, was good for closeups. I had enough
resolution for a conference call. Id I took two still pictures of the
same static scene, and averaged them together in Photoshop, I could
get rid of some of the blotchy color. (Averaging more pictures didn't
really help a lot more.) If I tried to work at a longer distance,
the limited resolution made identifying things or people, difficult.
If you cannot get a wide field of view plus a high resolution sensor,
another option is for the camera to have Pan/Tilt/Zoom (PTZ). Real PTZ
cameras cost $2000 and can slew quickly to a new view, and can cover
360 degrees. The one I was looking at, had a 56X zoom function.
This "toy" is a clever approximation.
Logitech QuickCam Orbit AF
http://www.amazon.com/Logitech-960-000111-QuickCam-Orbit-AF/dp/B000UY1OMY
The sensor size is claimed to be 2 megapixels, but at least in a
video capture situation, expect to not be able to capture all the
pixels, at 15 or 30 frames per second. You are more likely to see
640x480, and if the software is really bad, 320x240. The software
simply may not offer the option to capture video at a higher
setting. For still pictures, you may get better options, at least
up to the physical limit of the 2 megapixels.
That product does offer motorized tracking, and I suspect the "zoom"
function is digital. A proper zoom would be optical, as that doesn't
degrade the resolution when zooming. And this could be why it has
2 megapixels, so that when called upon to deliver 3x zoom, it
selects a 640x480 portion of the picture. I suppose, as long
as it manages to find the target to track, then only capturing
the AOI (area of interest), is good enough.
The product claims to have autofocus, but it might be
a fixed focus, good to some minimum distance until it becomes
blurry.
The reason I'm speaking in pessimistic terms about these products,
is so you don't get an overblown impression of what they can do.
Yes, they can capture a picture (if there is enough light - you
can buy infrared emitters to illuminate a darkened scene). The
picture may not have enough detail to ascertain a human
expression, at least at a distance of 3 meters. You're starting
to get too far away for detail.
In terms of software, the provided software will understand
what to do with the motors on the camera. But if there isn't a
standard API for devices like this, then third party software
may not be able to use the features to the same degree as
the provided software.
If you need extra light, then I'm sure the dog wouldn't care if
he was illuminated by a halogen lamp. As long as the lamp doesn't
heat up the room too much, I suppose that would work OK. If you
wanted stealth illumination, then there are LED based
illuminators...
http://www.supercircuits.com/index.asp?PageAction=VIEWPROD&ProdID=5436
It would be nice, if you could experiment with products like
this, at a local store. As that might reduce the odds of
buying something you don't end up using.
Another thing I forgot to mention - cheap cameras, with motors
on them, will use cheap plastic gears and/or drive trains. Such a
design could rapidly wear out, if the dog was pacing back and forth.
And for a toy design, I also would not expect the slew rate
to be that fast. So the dog may not always be centered in the
picture.
Paul
.
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