Force signal processing
AssigneeCambridge Touch Technologies Ltd.
InventorsRiccardo Micci, Arokia Nathan
Life of this patent
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Abstract
A method of processing a number of force values is described. Each force value corresponds to a sensor location. The sensor locations are spaced apart along a direction. The method includes receiving the force values (S11). The method also includes determining whether the force values include one or more candidate peaks (S12). Each candidate peak corresponds to a local maximum of the force values. The method also includes, in response to at least one candidate peak exceeds a minimum force threshold (S13), interpolating the force values and estimating a number of peak coordinates and corresponding peak force values based on the interpolated force values and the candidate peaks (S14) which exceed the minimum force threshold.
Claims20
A method of processing signals from a touch panel which comprises a layer of piezoelectric material arranged between a plurality of first electrodes and at least one second electrode, the method comprising:
- receiving one or more piezoelectric signals from the first electrodes, and correcting each piezoelectric signal to remove a first DC offset;
- integrating the one or more corrected piezoelectric signals to determine respective force values;
- maintaining a buffer storing buffer values, the buffer values corresponding to a preceding period;
- determining whether one or more user interactions are occurring based on a gradient and a variance calculated for the buffer values;
- and
- in response to determining that no user interactions are occurring, updating a second DC offset value;
- and
- calculating corrected force values based on the force values and the second DC offset value.
Apparatus for processing signals from a touch panel which comprises a layer of piezoelectric material arranged between a plurality of first electrodes and at least one second electrode, the apparatus configured to:
- receive one or more piezoelectric signals from the first electrodes;
- correct each piezoelectric signal to remove a first DC offset;
- integrate the one or more corrected piezoelectric signals to determine respective force values;
- maintain a buffer storing buffer values comprising corrected piezoelectric signal values corresponding to a preceding period;
- determine whether one or more user interactions are occurring based on a gradient and a variance calculated for the buffer values;
- and
- in response to determining that no user interactions are occurring, to update a second DC offset value;
- and
- calculate corrected force values based on the force values and the second DC offset value.
Apparatus for processing signals from a touch panel which comprises a layer of piezoelectric material arranged between a plurality of first electrodes and at least one second electrode, the apparatus configured to:
- receive one or more piezoelectric signals from the first electrodes;
- correct each piezoelectric signal to remove a first DC offset;
- integrate the one or more corrected piezoelectric signals to determine respective force values;
- maintain a buffer storing buffer values comprising force values corresponding to a preceding period;
- determine whether one or more user interactions are occurring based on a gradient and a variance calculated for the buffer values;
- and
- in response to determining that no user interactions are occurring, to update a second DC offset value;
- and
- calculate corrected force values based on the force values and the second DC offset value.
Dependencies are inferred from the claim text.