> I am trying to build a system that finds the X-Y position of about 400

So you will be "lookin' down the barrel of a gun"?  Or looking from the
side as the shot travels parallel to the X-Y plane.

Do you *really* need to have the X-Y position of each piece, or would some
sort of approximate density cloud image work?

Assuming you are looking down the barrel, you could get a high speed
digital camera to image it, I would think.  Looking from the side requires
quite a bit higher shutter speed to "freeze" the shot in mid flight.

I'm just afraid of the resolution requirements, though.  Even if 1 pixel
in the image were enough to represent one piece of shot, you would need a
minimum of  (4*12)/0.040 pixels in both the horizontal and vetical
(1200x1200), but the more pixels the better.  So, I would see if you could
reduce your 4' x 4' area a bit.

http://www.spectraservices.com/digital/cooke_hsfc_pro.html
http://www.rit.edu/~andpph/text-agfa-1280-hs.html
http://www.fillfactory.com/htm/track_record/htm/high_speed.htm

How accurate do the measurements need to be?  The easy way would be to
point the camera at the opening but not in the path of the shot, and
calibrate the camera to the opening with a homography.  If you really need
it "right", then you will have to calibrate the lens to recover the radial
distortion, etc.  With a high end lens, you may find the radial distortion
to be low enough that it can be ignored.

Once you acquire the image, a few image processing tricks may be able to
pull out the coords of all of the pieces of shot.  (Would it be acceptable
to only recover 300 of them?)  Would it be acceptable to have to sit in
front of a computer and hand pick them?  Is this whole setup already too
complicated?

> or electronics could handle this kind of speed, size of object, and volume
> of data all at the same time.

The above links address some of these issues.

I believe the last one is a camera that can do 1k x 1k pixels and 1000
fps, so your shot would move 1.4 feet between frames.  The shutter speed
is high enough to avoid motion blur.  1/100,000 sec shutter speed.


I am assuming that the image processing / position recovery can occur
off-line.


-Steve

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