| 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 rectangular touch surface with first and second spatial dimensions. A signal processor operates to transform energy values for the detection lines into Fourier coefficients arranged as data points on a regular grid defined by first and second frequency dimensions. To generate an interaction pattern for the touch surface, the signal processor operates a first 1D inverse FFT on the data points with respect to the second frequency dimension, so as to generate first values transformed into the second spatial dimension, and operates a second 1D inverse FFT on a selected subset of the first values with respect to the first frequency dimension to generate second values that represent the interaction pattern. The selected subset is defined by the data points that fall within an extent of the touch surface in the second spatial dimension, thereby reducing the total number of inverse FFT operations. |
