Touch determination with improved detection of weak interactions
AssigneeFlatFrog Laboratories AB
InventorsTomas CHRISTIANSSON, Nicklas OHLSSON
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Abstract
Touch sensitivity is enabled using a touch system that comprises a panel configured to conduct signals along detection lines across a touch surface. A signal processor obtains observed values for the detection lines, and identifies an interaction pattern on the touch surface as a solution to a 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.
Claims2
A method of enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus comprising a panel configured to conduct signals from a plurality of incoupling points to a plurality of outcoupling points, thereby defining detection lines that extend across a surface portion of the panel between pairs of incoupling and outcoupling points, at least one signal generator coupled to the incoupling points to generate the signals, and at least one signal detector coupled to the outcoupling points to generate the output signal which is indicative of interaction between one or more touching objects and one or more of the detection lines, wherein the method comprises the steps of:
- receiving the output signal;
- processing the output signal to obtain observed values for the detection lines;
- and
- identifying an interaction pattern for the surface portion as a solution to an optimization function that comprises an aggregation of differences between the observed value and a projected value for each of the detection lines, the projected value being given by a projection function that defines a functional relation between the interaction pattern and the projected value for the respective detection line;
- said method further comprising the steps of:
- computing a respective normalization value for each of the differences as a function of the observed value for the respective detection line;
- and
- applying the respective normalization value so as to normalize the respective difference in the optimization function.
-21. (canceled)
Dependencies are inferred from the claim text.