Periodic sensor panel baseline adjustment
First Claim
1. A method for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, the method comprising:
- performing a scan of the sensor panel to obtain new sensor output values;
normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and
performing baseline drift compensation at the chosen adjustment interval.
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Accused Products
Abstract
A periodic baseline adjustment algorithm is disclosed that can increment or decrement individual baseline sensor output values by one count to provide periodic fine-tuning of the baseline to track temperature drift. A scan of the sensor panel is performed after a dynamic adjustment time interval has passed. Previously computed offset values are subtracted from the sensor output values to normalize them. For any normalized sensor values that are positive, the offset values are incremented by one count. For any normalized sensor values that are negative, the offset values are decremented by one count. The algorithm waits the duration of a dynamic adjustment period before scanning the panel again. Dynamic adjustment intervals allow quick recovery for slight baseline inversions without adapting out far-field or touch objects very quickly. Adjustment intervals can depend on an average of background (non-patch) sensor output values.
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Citations
32 Claims
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1. A method for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, the method comprising:
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performing a scan of the sensor panel to obtain new sensor output values; normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and performing baseline drift compensation at the chosen adjustment interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, comprising:
a panel processor programmed for performing a scan of the sensor panel to obtain new sensor output values; normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and performing baseline drift compensation at the chosen adjustment interval. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, comprising:
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means for performing a scan of the sensor panel to obtain new sensor output values; means for normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; means for computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; means for choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and means for performing baseline drift compensation at the chosen adjustment interval.
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23. A non-transitory computer-readable medium comprising program code for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, the program code for causing performance of a method comprising:
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performing a scan of the sensor panel to obtain new sensor output values; normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and performing baseline drift compensation at the chosen adjustment interval. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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31. A mobile telephone including an apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, the apparatus comprising:
a panel processor programmed for performing a scan of the sensor panel to obtain new sensor output values; normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and performing baseline drift compensation at the chosen adjustment interval.
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32. A digital audio player including an apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, the apparatus comprising:
a panel processor programmed for performing a scan of the sensor panel to obtain new sensor output values; normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value; computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event; choosing an adjustment interval for the baseline drift compensation as a function of the computed background average; and performing baseline drift compensation at the chosen adjustment interval.
Specification