Recognizers / DollarOne

The $1 Unistroke Recognizer is a 2-D single-stroke recognizer designed for rapid prototyping of gesture-based user interfaces. In machine learning terms, $1 is an instance-based nearest-neighbor classifier with a Euclidean scoring function, i.e., a geometric template matcher. $1 is an extension of the proportional shape matching approach used in SHARK, which itself is an adaptation of Tappert's elastic matching approach with zero look-ahead. Despite its simplicity, $1 requires very few templates to perform well and is only about 100 lines of code, making it easy to deploy. An optional enhancement called Protractor improves $1's speed. The $N Multistroke Recognizer extends $1 to gestures with multiple strokes. The $P Point-Cloud Recognizer is the latest in the dollar family, performing unistroke and multistroke recognition without the combinatoric overhead of $N.