Baseline management for sensing device

1. A processing system for baseline management, comprising:

a sensor module comprising sensor circuitry coupled to a plurality of sensor electrodes, the sensor module configured to receive resulting signals with at least a portion of the sensor electrodes; and

a determination module operatively connected to the plurality of sensor electrodes and configured to:

obtain a first profile from the resulting signals;

calculate, using the first profile, a first statistic and a second statistic for the first profile;

select, according to a first range of the first statistic and a second range of the second statistic, a baseline relaxation technique from a plurality of baseline relaxation techniques to obtain a selected baseline relaxation technique; and

adjust a baseline for the capacitance sensing input device according to the selected baseline relaxation technique.

2. The processing system of claim 1 , wherein calculating the first statistic comprises:

calculating a noise statistic for the predetermined timeframe;

calculating a data signal statistic for the predetermined timeframe using the first profile;

calculating a signal to noise ratio (SNR) by dividing the data signal statistic by the noise statistic; and

dividing the SNR by a detection threshold to obtain a relative SNR (RSNR),

wherein the RSNR is the first statistic.

3. The processing system of claim 2 , wherein the second statistic comprises a zero order moment (ZOM) of the first profile.

4. The processing system of claim 3 , selecting the baseline relaxation technique comprises:

selecting one of a fast baseline relaxation and a slow baseline relaxation based on a comparison of the RSNR to a high RSNR threshold and a low RSNR threshold and a comparison of the ZOM to a positive ZOM threshold and a negative ZOM threshold.

5. The processing system of claim 3 , wherein the second range of the ZOM is defined by a plurality of ZOM thresholds, wherein the plurality of ZOM thresholds are periodically updated using a plurality of profiles.

6. The processing system of claim 1 , wherein the plurality of baseline relaxation techniques comprises a variety of baseline relaxation speeds defining how quickly to adjust the sensing baseline.

7. The processing system of claim 1 , wherein the first profile is obtained for the first axis of the capacitance sensing input device, and wherein the determination module is further configured to:

obtain a second profile for a second axis of the capacitance sensing input device; and

calculate, using the second profile, a third statistic and a fourth statistic for the second profile,

wherein selecting the baseline relaxation technique is further performed according to a third range of the third statistic and a fourth range of the fourth statistic.

8. The processing system of claim 7 , wherein the determination module is further configured to:

detect a discrepancy between the first range and the third range,

wherein selecting the selected baseline relaxation technique is based on the discrepancy.

9. A method for baseline management for a capacitive sensing device, comprising:

obtaining a first profile from sensing signals received with a plurality of sensor electrodes of the capacitance sensing input device;

calculating, using the first profile, a first statistic and a second statistic for the first profile;

selecting, according to a first range of the first statistic and a second range of the second statistic, a baseline relaxation technique from a plurality of baseline relaxation techniques to obtain a selected baseline relaxation technique; and

adjusting a baseline for the capacitance sensing input device according to the selected baseline relaxation technique.

10. The method of claim 9 , wherein calculating the first statistic comprises:

calculating a noise statistic for the predetermined timeframe;

calculating a data signal statistic for the predetermined timeframe using the first profile;

calculating a signal to noise ratio (SNR) by dividing the data signal statistic by the noise statistic; and

dividing the SNR by a detection threshold to obtain a relative SNR (RSNR),

wherein the RSNR is the first statistic.

11. The method of claim 10 , wherein the second statistic comprises a zero order moment (ZOM) of the first profile.

12. The method of claim 11 , selecting the baseline relaxation technique comprises:

selecting one of a fast baseline relaxation and a slow baseline relaxation based on a comparison of the RSNR to a high RSNR threshold and a low RSNR threshold and a comparison of the ZOM to a positive ZOM threshold and a negative ZOM threshold.

13. The method of claim 11 , wherein the second range of the ZOM is defined by a plurality of ZOM thresholds, wherein the plurality of ZOM thresholds are periodically updated using a plurality of profiles.

14. The method of claim 9 , wherein the plurality of baseline relaxation techniques comprises a variety of baseline relaxation speeds defining how quickly to adjust the sensing baseline.

15. The method of claim 9 , wherein the first profile is obtained for the first axis of the capacitance sensing input device, and wherein the method further comprises:

obtaining a second profile for a second axis of the capacitance sensing input device; and

calculating, using the second profile, a third statistic and a fourth statistic for the second profile,

wherein selecting the baseline relaxation technique is further performed according to a third range of the third statistic and a fourth range of the fourth statistic.

16. The method of claim 15 , further comprising:

detect a discrepancy between the first range and the third range,

wherein selecting the selected baseline relaxation technique is based on the discrepancy.

17. An input device comprising:

a plurality of sensor electrodes configured to receive sensing signals; and

a processing system operatively connected to the plurality of sensor electrodes and configured to:

obtain a profile from the resulting signals;

calculate, using the profile, a first statistic and a second statistic for the profile;

select, according to a first range of the first statistic and a second range of the second statistic, a baseline relaxation technique from a plurality of baseline relaxation techniques to obtain a selected baseline relaxation technique; and

adjust a baseline for the capacitance sensing input device according to the selected baseline relaxation technique.

18. The input device of claim 17 , wherein calculating the first statistic comprises:

calculating a noise statistic for a predetermined timeframe;

calculating a data signal statistic for the predetermined timeframe using the profile;

calculating a signal to noise ratio (SNR) by dividing the data signal statistic by the noise statistic; and

dividing the SNR by a detection threshold to obtain a relative SNR (RSNR),

wherein the RSNR is the first statistic.

19. The input device of claim 18 , wherein the second statistic comprises a zero order moment (ZOM) of the first profile.

20. The input device of claim 19 , wherein the second range of the ZOM is defined by a plurality of ZOM thresholds, wherein the plurality of ZOM thresholds are periodically updated using a plurality of profiles.