Touch determination with improved detection of weak interactions
First Claim
1. A method of enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus including a panel and a plurality of emitters and a plurality of detectors defining detection lines that extend across a surface portion of the panel between pairs of emitters and detectors, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of emitters to generate signals, and at least one signal detector coupled to the plurality of detectors to generate the output signal, the output signal being indicative of interaction between one or more touching objects and one or more of the detection lines, wherein the method comprises:
- processing the output signal to obtain observed values for a plurality of the detection lines;
for each respective detection line among the plurality of the detection linesgenerating a projected value for the respective detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the respective detection line, the fitted interaction pattern having at least one basis function defining an attenuation strength at a position on the surface portion within a two-dimensional extent, wherein the projection function models a projected value for each respective detection line as a sum of contributions from the at least one basis function arranged on the surface portion;
calculating a difference value between an observed value for the respective detection line and the projected value for the respective detection line, andupdating the fitted interaction pattern based on an optimization function to minimize the difference value; and
processing the fitted interaction pattern to determine a touch interaction.
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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.
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Citations
20 Claims
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1. A method of enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus including a panel and a plurality of emitters and a plurality of detectors defining detection lines that extend across a surface portion of the panel between pairs of emitters and detectors, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of emitters to generate signals, and at least one signal detector coupled to the plurality of detectors to generate the output signal, the output signal being indicative of interaction between one or more touching objects and one or more of the detection lines, wherein the method comprises:
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processing the output signal to obtain observed values for a plurality of the detection lines; for each respective detection line among the plurality of the detection lines generating a projected value for the respective detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the respective detection line, the fitted interaction pattern having at least one basis function defining an attenuation strength at a position on the surface portion within a two-dimensional extent, wherein the projection function models a projected value for each respective detection line as a sum of contributions from the at least one basis function arranged on the surface portion; calculating a difference value between an observed value for the respective detection line and the projected value for the respective detection line, and updating the fitted interaction pattern based on an optimization function to minimize the difference value; and processing the fitted interaction pattern to determine a touch interaction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device for enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus including a panel and a plurality of emitters and a plurality of detectors defining detection lines that extend across a surface portion of the panel between pairs of emitters and detectors, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of emitters to generate signals, and at least one signal detector coupled to the plurality of detectors to generate the output signal, the output signal being indicative of interaction between one or more touching objects and one or more of the detection lines, said device comprising:
a signal processor configured to process the output signal to obtain observed values for a plurality of the detection lines; for each respective detection line among the plurality of the detection lines generate a projected value for the respective detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the respective detection line, the fitted interaction pattern having at least one basis function defining an attenuation strength at a position on the surface portion within a two-dimensional extent, wherein the projection function models a projected value for each respective detection line as a sum of contributions from the at least one basis function arranged on the surface portion, calculate a difference value between an observed value for the respective detection line and the projected value for the respective detection line, and update the fitted interaction pattern based on an optimization function to minimize the difference value; and process the fitted interaction pattern to determine a touch interaction. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A touch-sensitive apparatus, comprising:
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a panel, a plurality of emitters and a plurality of detectors defining detection lines that extend across a surface portion of the panel between pairs of emitters and detectors; at least one signal generator configured to generate signals at the plurality of emitters; at least one signal detector configured to generate an output signal based on detected signals at the plurality of detectors; and a signal processor coupled to the at least one signal detector, the signal processor configured to process the output signal to obtain observed values for a plurality of the detection lines, for each respective detection line among the plurality of the detection lines generate a projected value for the respective detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the respective detection line, the fitted interaction pattern having at least one basis function defining an attenuation strength at a position on the surface portion within a two-dimensional extent, wherein the projection function models a projected value for each respective detection line as a sum of contributions from the at least one basis function arranged on the surface portion, calculate a difference value between an observed value for the respective detection line and the projected value for the respective detection line, and update the fitted interaction pattern based on an optimization function to minimize the difference value, and process the fitted interaction pattern to determine a touch interaction. - View Dependent Claims (19, 20)
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Specification