Specifying gestures by example.

Paper
Rubine, Dean. Specifying gestures by example. Vol. 25. No. 4. ACM, 1991.
Publication Link: http://dl.acm.org/citation.cfm?id=122753

Summary

In this paper, Rubine introduces a gesture recognition based framework for a user interface. The primary driver for the recognition used by the GRANDMA system is a set of classical physics based features (13 of them). These features capture the dynamics of a stroke. In doing so, the features try to differentiate between the speed, angular velocity, shape, length and other similar characteristics of features.

Discussion

Pros

The method used to develop these features are very simplistic but appear to be effective based on the results delivered in the paper. I'd be interested in seeing the full dissertation for this work to see what was left out.
The use of graphics and pictorial illustration was masterful. Many of the concepts used in the paper are captured and described beautifully in the text.

Cons.

I find none. This was a very thorough first step at using features to describe gestures (which intuitively are just odd shapes). And on that note, i think a fine motivation for the features would have been tying these features to classical geometry, physics, and psychology. How does the human brain recognize the difference between a circle and a square? Or better: If one were asked to traverse a path (physically) while blindfolded, how does one mentally picture the shape of the path? The mechanics involved in this (how the brain intuitively solves this problem) are not very different from Rubines approach.