Patent ID: 9430079
Filing Date: 2016-08-30
CPC Classification: G06F

Claim Text:
1. A method for determining touch data in a touch-sensing apparatus, said apparatus including a light transmissive panel that defines a touch surface and an opposite surface, a light source arrangement for providing sheets of light inside the panel, wherein each sheet includes light that propagates by internal reflection between the touch surface and the opposite surface from an incoupling site to an outcoupling site, said apparatus further including a light sensor arrangement for detecting light reaching the outcoupling site, wherein the touch-sensing apparatus is configured such that one or more objects touching the touch surface causes a local attenuation of at least two sheets of light, said method comprising: obtaining at least one projection signal which is indicative of a spatial distribution of light within said outcoupling site; processing said at least one projection signal for identification of signal profiles representing said attenuation; identifying, based on the signal profiles, one or more candidate touch areas on the touch surface; processing, after identifying the one or more candidate touch areas, said at least one projection signal to reconstruct a two-dimensional distribution of signal values only within said one or more candidate touch areas, the two-dimensional distribution of signal values being a two-dimensional image of signal energy attenuation values associated with the at least one projection signal; and determining touch data for the or each object by processing the reconstructed signal values within the candidate touch areas.