Low-cost gestural interaction based on motion estimation of a projected dot pattern : Experiments with a working prototype

The concept and realization of an easy-to-use, low-cost handheld IR optical sensor for universal, long-range gesture-controlled operation of technical devices is presented and recognition results with a working prototype are given. The system comprises two elements: a handheld buttonless light emitter which resembles a small laser pointer but emits a wide-angle IR random-dot pattern along with a visible light beam (for device selection) and a small photo-sensor array along with a processing/decoder unit near or in the device to be controlled. The emitted IR light is spatially modulated by a diffractive optical element (DOE) which has a specially designed micro-structured surface to generate a binary pseudo-random array of light beams. This concept allows to come up with a handheld device which contains only a few inexpensive mass-market components (since the IR-optical signal is both the information and transmission channel). User experience and gesture recognition capabilities were examined with a group of 29 elderly volunteers who were asked to repeatedly "draw" quasi-intuitive gestures with the handheld emitter towards typical home appliances like light switch, blinds, heating device, and door from distances of up to 6 meters. Applying a correlation-based reconstruction algorithm and adaptive rule-based pattern recognition with low computational load for real-time processing on low-end processors, an overall recognition rate of 94 % could be achieved so far. As the algorithm is being optimized to enable sequential spotting of meaningful gestures and enhanced class separation, the list of gestures will be extended.