To: galt%peruvian@cs.utah.edu, lance@roi.ca41.csd.mot.com,
        dstamp@watserv1.uwaterloo.ca
Subject: Re: simple code to get simple gestures
Cc: glove-list@karazm.math.uh.edu
Message-Id: <9110141715.AA12550@roi.ca41.csd.mot.com>
Date: 14 Oct 91 17:15:36 PDT (Mon)
From: Lance Norskog <lance@roi.ca41.csd.mot.com>
	> 
	Sounds like a Kalman predictive filter.  The question is, how much will
	the overshoots affect operator performance?
	If you're going to develop the code for such a filter, I hope you make
	several versions, using different delays.  This would allow users to
	match the filter to their own system's video display, rendering and
	processing times.  Isuggest multiples of 33 mS.
	Also, it would be interesting to set up a simple system using a "bar"
	cursor or other easy-to-draw symbol, and try out the effect of changing
	the filter coefficients.  After all, we're getting into psychophysics
	here, and that is *not* an easy field to predict.  I've noticed weird
	"viscous" effects using head-position to cursor feedback with a system
	delay of 50 mS or less.  Addition of hysterisis of 1/6 visual degree
	stopped that, and reduced noise, but at the cost of some of the 
	"reality" feel of the system.  It's amazing how little it takes to 
	make such feedback feel like a "tool" rather than an extension of
	the body.

Sounds like you know what you're talking about and I don't.

Yes, this needs a lot of experimentation, and preferably a
menu and calibration system.  I don't believe in canned software.
"I know what you need.  Trust me!"

References, please?  Should I look for books by Kalman at the
Stanford CS library?  References in CACM year-end indices?

Thanks,

Lance Norskog