| 摘要 |
Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by TIR, from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines across a touch surface between pairs of incoupling and outcoupling points. A signal processor operates in a repeating sequence of iterations to: calculate (22) change values for the detection lines representative of signal changes between the current and a previous iteration, and operate (23) a reconstruction algorithm on the change values to determine a differential interaction pattern across the touch surface. The signal processor also operates to update (24) a tracking pattern as a function of the differential interaction pattern, and generate (25) a current offset pattern based on the tracking pattern. The offset pattern is generated to represent current touch interaction on the touch surface and is supplied for identification (26) of touches on the surface portion. The tracking pattern may represent accumulated interaction across the touch surface, and may either include or be at least partly compensated for the influence of contaminations on the touch surface. |
