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 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, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of incoupling points to generate the signals, and at least one signal detector coupled to the plurality of outcoupling points to generate the output signal, the output signal 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 of the plurality of the detection linescomputing a normalization value for the detection line as a function of the observed value for the detection line,generating a projected value for the detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the detection line,calculating a difference value between the observed value for the detection line and the projected value for the detection line,computing a normalized difference value for the difference value based on the normalization value for the detection line,updating the fitted interaction pattern based on an optimization function to minimize the normalized difference value; and
processing the fitted interaction pattern to determine touch interaction.
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Accused Products
Abstract
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 observed values for the detection lines, and identify 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 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.
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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 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, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of incoupling points to generate the signals, and at least one signal detector coupled to the plurality of outcoupling points to generate the output signal, the output signal 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 of the plurality of the detection lines computing a normalization value for the detection line as a function of the observed value for the detection line, generating a projected value for the detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the detection line, calculating a difference value between the observed value for the detection line and the projected value for the detection line, computing a normalized difference value for the difference value based on the normalization value for the detection line, updating the fitted interaction pattern based on an optimization function to minimize the normalized difference value; and processing the fitted interaction pattern to determine touch interaction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A device for enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus including 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, the touch-sensitive apparatus further including at least one signal generator coupled to the plurality of incoupling points to generate the signals, and at least one signal detector coupled to the plurality of outcoupling points to generate the output signal, the output signal 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 of the plurality of the detection lines compute a normalization value for the detection line as a function of the observed value for the detection line, generate a projected value for the detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the detection line, calculate a difference value between the observed value for the detection line and the projected value for the detection line, compute a normalized difference value for the difference value based on the normalization value for the detection line, update the fitted interaction pattern based on an optimization function to minimize the normalized difference value; and process the fitted interaction pattern to determine touch interaction.
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20. A touch-sensitive apparatus, comprising:
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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 configured to generate the signals at the plurality of incoupling points; at least one signal detector configured to generate an output signal based on detected signals at the plurality of outcoupling points; 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 of the plurality of the detection lines compute a normalization value for the detection line as a function of the observed value for the detection line, generate a projected value for the detection line based on a projection function that defines a functional relation between a fitted interaction pattern and the projected value for the detection line; calculate a difference value between the observed value for the detection line and the projected value for the detection line, compute a normalized difference value for the difference value based on the normalization value for the detection line, update the fitted interaction pattern based on an optimization function to minimize the normalized difference value, and process the fitted interaction pattern to determine touch interaction.
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Specification