MAGIC summoning: towards automatic suggesting and testing of gestures with low probability of false positives during use

Gestures for interfaces should be short, pleasing, intuitive, and easily recognized by a computer. However, it is a challenge for interface designers to create gestures easily distinguishable from users' normal movements. Our tool MAGIC Summoning addresses this problem. Given a specific platform and task, we gather a large database of unlabeled sensor data captured in the environments in which the system will be used (an \"Everyday Gesture Library\" or EGL). The EGL is quantized and indexed via multi-dimensional Symbolic Aggregate approXimation (SAX) to enable quick searching. MAGIC exploits the SAX representation of the EGL to suggest gestures with a low likelihood of false triggering. Suggested gestures are ordered according to brevity and simplicity, freeing the interface designer to focus on the user experience. Once a gesture is selected, MAGIC can output synthetic examples of the gesture to train a chosen classifier (for example, with a hidden Markov model). If the interface designer suggests his own gesture and provides several examples, MAGIC estimates how accurately that gesture can be recognized and estimates its false positive rate by comparing it against the natural movements in the EGL. We demonstrate MAGIC's effectiveness in gesture selection and helpfulness in creating accurate gesture recognizers.