C. van Wrede, P. Laskov, and G. Ratsch, "Using classification to determine the number of finger strokes on a multi-touch tactile device," European Symposium on Artificial Neural Networks, pp. 549-554, 2004.
Abstract: On certain types of multi-touch touchpads, determining the number of finger stroke is a non-trivial problem. We investigate the application of several classification algorithms to this problem. Our experiments are based on a flat prototype of the spherical Touchglobe touchpad. We demonstrate that with a very short delay after the stroke, the number of touches can be determined by a Support Vector Machine with an RBF kernel with an accuracy of about 90% (on a 5-class problem).