From: dstamp@watserv1.waterloo.edu (Dave Stampe-Psy+Eng)
Subject: TECH: Cheap video tracker update
Date: Tue, 4 Feb 1992 00:24:55 GMT
Message-ID: <1992Feb4.002455.2022@watserv1.waterloo.edu>
Organization: University of Waterloo



Well, the cheap video tracker PC card I've been working on is working
(in hardware, the software's in early stages) but it looks great.
This is a card for 286, 386 and 486 PCs that accepts camera input
(inexpensive monochrome cameras work best) and extracts pertinant edge data
in realtime. 

The big deal in this card is that it offloads the effort of edge detection
and point extraction from the host processor (as compared to a frame
grabber).  For example, it would take a 486/25 about 10 mS per frame to 
extract edges from a 640x240 image (same as this card), whereas this card would
only take 500-800 uS to read out.  Also, since this card uses no video
buffer, it is substantially cheaper ($200-500, depending on qty.)

Currently, it's accepting 60 fps of video, extracting over 4000 points
and redrawing it on the VGA monitor at 15 fps.  This just an intermediate
stage in software development, but it shows the potential already.  Here
are some other possible uses:

Point tracking:  It can track >100 points in an image at 16 fps (total
delay: 20-30 mS from movement till computer recovers data).  I have tried
infrared LEDs using a filter in the camera, and it could easily see them
from 12 feet away in a brightly lit room.  (It could even see them from
the back!).

Silhouette input:  Plenty of VR work is being done with gesturing in
front of white screens.  This board was able to pick out all the fingers
on my hand even though it only covered about 1/2 inch on the VGA monitor.
This was under nonideal whitescreen situations, including substantial
sidelighting.

Stereoscopic point location:  Two of these can be put on one PC card,
and with 2 cheap cameras and special software, you can track objects
accurately in depth as well.

Electronic data and teletext:  The card was designed to "see" the 
vertical interval picture area, which contains digital teletext and
close-captioned data on some programs.  Turn your PC into a digital 
data device...

Head tracking:  Special combinations of LEDs and/or targets on a VR 
headset and gloves can be used for realtime input.  Need to work on
the best combination of points for this some more.  Even better, put
the camera on the HMD, and  have a grid of computer-controlled LEDS 
every 3' or so on the walls, ceiling etc.

Eye tracking:  In a few months, I'll look at replacing costly eyetracker
hardware with this card. It can do corneal spot tracking easily, but 
pupil tracking may require more work.

Can anyone think of other applications?  It's going to a market review
in a month or so, and I'd like to have a few more ideas to present.



--------------------------------------------------------------------------
| My life is Hardware,                    |                              | 
| my destiny is Software,                 |         Dave Stampe          |
| my CPU is Wetware...                    |                              | 
| Anybody got a SDB I can borrow?         | dstamp@watserv1.uwaterloo.ca |
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