A domain-independent system for sketch recognition.

Paper
Yu, Bo, and Shijie Cai. "A domain-independent system for sketch recognition." Proceedings of the 1st international conference on Computer graphics and interactive techniques in Australasia and South East Asia. ACM, 2003.
Publication Link: http://dl.acm.org/citation.cfm?id=604499

Summary

In this work, Bo et al. developed a user interface for recognizing low-level and high level sketches without prior domain knowledge as a source for performance improving constraints. Their system is able to recognize smooth curves, hybrid shapes and polylines. 

Discussion

Pros

One interesting merit is their ability to use only low-level geometric content of the strokes to achieve object recognition.
They make very good use of diagram illustrations that help to understand some of the poorly described algorithms used in the paper.
The equations presented for direction and curvature are interesting. Since they are not cited, I assume they developed this metric, which proved to be quite useful.
Overall I think the work is impressive.

Cons.

I feel that there are too many hard-coded rules used in this work to make it truly 'generic'. The authors themselves attest to this fact.
They also do not provide any useful data indicating where the system fails and why, which i feel is important.