Reduce stylus tip wobble when coupled to capacitive sensor
First Claim
1. A method for reducing wobble in a calculated position of a stylus, the method comprising:
- determining a first position estimate along an axis of a touch sensor panel using a first position calculation;
determining a second position estimate along the axis of the touch sensor panel using a second position calculation;
calculating a ratio of a second largest amplitude signal and a third largest amplitude signal;
assigning weighting to the first and second calculated position estimates based on a proximity of the stylus to an electrode receiving a largest amplitude signal, wherein full weight is assigned to the first position estimate and zero weight is assigned to the second position estimate when the ratio of the second largest amplitude signal and the third largest amplitude signal is within a threshold value of unity;
determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and
updating a user interface according to the calculated position, wherein the user interface is displayed on a display device coupled to the touch sensor panel.
1 Assignment
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Accused Products
Abstract
Algorithms can be used to reduce stylus tip wobble for a stylus translating on a surface over and between electrodes of a touch sensor panel. In some examples, a first position estimate can be calculated using a first position calculation method and a second position estimate can be calculated using a second position calculation method. The position of the stylus can be determined based on a weighted combination of the first and second position estimates. In some examples, the first position estimate can be calculated using an even-point centroid of signal contributions from an even number of electrodes of a touch sensor panel and the second position estimate can be calculated using an odd-point centroid of signal contributions from an odd number of electrodes. In some examples, the weighting can be assigned based on a ratio of the two largest amplitude signals and based on a ratio of the second and third largest amplitude signals.
30 Citations
20 Claims
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1. A method for reducing wobble in a calculated position of a stylus, the method comprising:
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determining a first position estimate along an axis of a touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a ratio of a second largest amplitude signal and a third largest amplitude signal; assigning weighting to the first and second calculated position estimates based on a proximity of the stylus to an electrode receiving a largest amplitude signal, wherein full weight is assigned to the first position estimate and zero weight is assigned to the second position estimate when the ratio of the second largest amplitude signal and the third largest amplitude signal is within a threshold value of unity; determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on a display device coupled to the touch sensor panel. - View Dependent Claims (2, 3, 4, 5)
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6. A method for reducing wobble in a calculated position of a stylus comprising:
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determining a first position estimate along an axis of a touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a first ratio of a second largest amplitude signal and a third largest amplitude signal; calculating a second ratio of a largest amplitude signal and the second largest amplitude signal; determining the proximity of the stylus to an electrode receiving the largest amplitude signal based on at least one of the first or second ratios; assigning weighting to the first and second calculated position estimates based on the determined proximity of the stylus to the electrode receiving the largest amplitude signal, wherein the first position estimate is weighted based on the ratio of the largest amplitude signal and the second largest amplitude signal; determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on a display device coupled to the touch sensor panel. - View Dependent Claims (7, 8)
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9. A system for improving accuracy in a stylus measurement, comprising:
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a plurality of electrodes arranged along an axis of a touch sensor panel capable of receiving a plurality of signals; a display device coupled to the touch sensor panel; and one or more processors capable of; determining a first position estimate along the axis of the touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a ratio of a second largest amplitude signal and a third largest amplitude signal; assigning weighting to the first and second calculated position estimates based on a proximity of the stylus to an electrode of the plurality of electrodes receiving a largest amplitude signal, wherein full weight is assigned to the first position estimate and zero weight is assigned to the second position estimate when the ratio of the second largest amplitude signal and the third largest amplitude signal is within a threshold value of unity; determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on the display device. - View Dependent Claims (10, 11, 12, 13)
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14. A system for improving accuracy in a stylus measurement, comprising:
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a plurality of electrodes arranged along an axis of a touch sensor panel capable of receiving a plurality of signals; a display device coupled to the touch sensor panel; and one or more processors capable of; determining a first position estimate along the axis of the touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a first ratio of a second largest amplitude signal and a third largest amplitude signal; calculating a second ratio of a largest amplitude signal and the second largest amplitude signal; determining the proximity of the stylus to the electrode receiving the largest amplitude signal based on at least one of the first or second ratios; assigning weighting to the first and second calculated position estimates based on the determined proximity of the stylus to the electrode receiving the largest amplitude signal, wherein the first position estimate is weighted based on the ratio of the largest amplitude signal and the second largest amplitude signal; determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on the display device. - View Dependent Claims (15, 16)
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17. A non-transitory computer readable storage medium, the computer readable storage medium containing instructions that, when executed, perform a stylus position error correction method, the method comprising:
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determining a first position estimate along an axis of a touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a ratio of a second largest amplitude signal and a third largest amplitude signal; assigning weighting to the first and second calculated position estimates based on a proximity of the stylus to an electrode receiving a largest amplitude signal, wherein full weight is assigned to the first position estimate and zero weight is assigned to the second position estimate when the ratio of the second largest amplitude signal and the third largest amplitude signal is within a threshold value of unity; determining a calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on a display device coupled to the touch sensor panel. - View Dependent Claims (18, 19)
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20. A non-transitory computer readable storage medium, the computer readable storage medium containing instructions that, when executed, perform a stylus position error correction method, the method comprising:
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determining a first position estimate along an axis of a touch sensor panel using a first position calculation; determining a second position estimate along the axis of the touch sensor panel using a second position calculation; calculating a first ratio of a second largest amplitude signal and a third largest amplitude signal; calculating a second ratio of a largest amplitude signal and the second largest amplitude signal; determining the proximity of the stylus to the electrode receiving the largest amplitude signal based on at least one of the first or second ratios; assigning weighting to the first and second calculated position estimates based on the determined proximity of the stylus to the electrode receiving the largest amplitude signal, wherein the first position estimate is weighted based on the ratio of the largest amplitude signal and the second largest amplitude signal and the second position estimate is weighted based on the ratio of the second largest amplitude signal and the third largest amplitude signal; determining the calculated position of the stylus based on a weighted combination of the first and second position estimates; and updating a user interface according to the calculated position, wherein the user interface is displayed on a display device coupled to the touch sensor panel.
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Specification