Patent ID: 8803848

Claim:
A touch sensitive human-computer interaction device comprising: a waveguide having a touch surface; a plurality of light emitters optically coupled at input locations around the periphery of the waveguide touch surface to emit light signals for transmission through the waveguide by the internal reflection effect, wherein one or more touch interactions on the touch surface of the waveguide alters the light conductivity of the waveguide in the location(s) of the one or more touch interactions causing frustration of the internal reflection effect; a plurality of detectors optically coupled at output locations around the periphery of the waveguide touch surface to receive the light signals along respective sensing signal paths defined between each respective pair of light emitter and detector, and arranged with a device comprising an analog to digital converter to output respective signals on the basis of the light signals received; wherein each output signal is representative of the level of frustration of the internal reflection caused by one or more touch interactions along the respective sensing signal paths, and wherein each output signal is alterable by each of a plurality of simultaneous touch interactions along a single sensing signal path of the respective signal paths; and a data processor operatively coupled to the device comprising the analog to digital converter and arranged to process said output signals according to a reconstruction algorithm to obtain a digital representation of said light conductivity and, based on the reconstruction, to output a signal for controlling a visualization device, wherein the reconstruction algorithm is a Computerized Tomography reconstruction algorithm.