摘要 |
Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals, e.g. by TIR, along detection lines across a touch surface. A signal processor operates to obtain (52) observed values for the detection lines, and identify (54C) an interaction pattern on the touch surface as a solution to an optimization function that comprises an aggregation of differences, for each detection line, between the observed value and a projected value, which is given by a projection function that defines a functional relation between the interaction pattern and the projected value for each detection line. The signal processor implements a normalization to ensure that the interaction pattern indicates weak touches even in the presence of strong touches. The normalization involves computing (54A) a respective normalization value for each of the differences as a function of the observed value for the respective detection line; and applying (54B) the respective normalization value so as to normalize the respective difference in the optimization function. |