Accelerometer-based systems and methods for quantifying steps
Systems and methods detect steps from one or more sensed accelerometer signals. Systems comprise an accelerometer and a non-transitory computer readable medium, each of which communicates with a processor. The accelerometer is coupled to an individual and generates outputs received by the processor. The non-transitory computer readable medium stores instructions controlling the processor to perform steps of a method. The processor determines a minimum and a maximum reading for respective time periods. Counted peak heights are maxima that exceed a rest threshold. The rest threshold may be a function of the rest maximum. The processor determines a peak threshold for each time period having a counted peak height. A counted amplitude comprises the difference between the maximum reading and minimum readings of a time period in which the counted peak height exceeds the peak threshold. The processor increments a step counter when a counted amplitude exceeds an amplitude threshold.
1. A method for counting steps from a plurality of accelerometer outputs of an accelerometer, the accelerometer generating the plurality of accelerometer outputs while being coupled to an individual, the method executed by a processor in communication with a non-transitory computer readable medium, the non-transitory computer readable medium storing instructions for execution by the processor to execute the method, the method comprising:
receiving the plurality of accelerometer outputs;
determining a plurality of time periods, wherein each of the plurality of time periods is a time period;
determining readings based at least in part on the plurality of accelerometer outputs;
identifying counted peak heights, wherein each of the counted peak heights comprises a maximum reading during a time period in which the maximum reading is greater than a rest threshold, wherein the rest threshold is determined by:
receiving readings for a period of rest,
identifying a rest maximum, wherein the rest maximum comprises a greatest reading generated by the accelerometer for the period of rest, and
determining the rest threshold based at least in part on the rest maximum;
determining a peak threshold for each of the plurality of time periods with a counted peak height, wherein the peak threshold comprises a weighted average of two or more counted peak heights; and
incrementing a counter responsive to the counted peak height exceeding the peak threshold associated with the time period in which the counted peak height occurred, wherein a number stored by the counter represents a number of steps taken by the individual.
2. The method of claim 1 , wherein the accelerometer measures linear acceleration along a vertical axis.
3. The method of claim 1 , wherein the method further comprises applying a data-smoothing function to the plurality of accelerometer outputs of the accelerometer to determine the readings.
4. The method of claim 3 , wherein the data-smoothing function comprises one or more of a low-pass filter, a moving average, or a curve-fitting function.
5. The method of claim 1 , wherein each of the plurality of time periods is of equal duration.
6. The method of claim 1 , wherein determining the rest threshold comprises one or more of:
multiplying the rest maximum by a coefficient greater than or equal to one; or
adding a fixed value to the rest maximum.
7. The method of claim 1 , wherein the two or more counted peak heights immediately precede each time period having a counted peak height.
8. The method of claim 1 , wherein the accelerometer measures linear acceleration along three axes and the plurality of accelerometer outputs from the three axes are combined.
9. A system for counting steps from a plurality of accelerometer outputs of an accelerometer, the accelerometer generating the plurality of accelerometer outputs while being coupled to an individual, the system comprising:
a processor in communication with a non-transitory computer-readable medium, the non-transitory computer-readable medium storing instructions for execution by the processor to cause the system to at least:
receive the plurality of accelerometer outputs;
determine a plurality of time periods, wherein each of the plurality of time periods is a time period;
determine readings based at least in part on the plurality of accelerometer outputs;
identify counted peak heights, wherein each of the counted peak heights comprises a maximum reading during a time period in which the maximum reading is greater than a rest threshold, wherein the rest threshold is determined by:
receiving readings for a period of rest,
identifying a rest maximum, wherein the rest maximum comprises a greatest reading generated by the accelerometer for the period of rest, and
determining the rest threshold based at least in part on the rest maximum;
determine a peak threshold for each of the plurality of time periods with a counted peak height, wherein the peak threshold comprises a weighted average of two or more counted peak heights; and
increment a counter responsive to the counted peak height exceeding the peak threshold associated with the time period in which the counted peak height occurred, wherein a number stored by the counter represents a number of steps taken by the individual.
10. The system of claim 9 , wherein the accelerometer measures linear acceleration along a vertical axis.
11. The system of claim 9 , wherein the non-transitory computer-readable medium storing instructions for execution by the processor to further cause the system to at least apply a data-smoothing function to the plurality of accelerometer outputs to determine the readings.
12. The system of claim 11 , wherein the data-smoothing function comprises one or more of a low-pass filter, a moving average, or a curve-fitting function.
13. The system of claim 9 , wherein each of the plurality of time periods is of equal duration.
14. The system of claim 9 , wherein determining the rest threshold comprises one or more of:
multiplying the rest maximum by a coefficient greater than or equal to one; or
adding a fixed value to the rest maximum.
15. The system of claim 9 , wherein the two or more counted peak heights are the two or more counted peak heights immediately preceding each time period having a counted peak height.
16. The system of claim 9 , wherein the system further comprises a display screen for displaying information comprising the number stored by the counter.
17. The system of claim 9 , wherein the accelerometer measures linear acceleration along three axes and the plurality of accelerometer outputs from the three axes are combined.
18. A computer program product for counting steps from a plurality of accelerometer outputs of an accelerometer, the accelerometer generating the plurality of accelerometer outputs while being coupled to an individual, the computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions, when executed, are configured to:
receive the plurality of accelerometer outputs;
determine a plurality of time periods, wherein each of the plurality of time periods is a time period;
determine readings based at least in part on the plurality of accelerometer outputs;
identify counted peak heights, wherein each of the counted peak heights comprises a maximum reading during a time period in which the maximum reading is greater than a rest threshold, wherein the rest threshold is determined by:
receiving readings for a period of rest,
identifying a rest maximum, wherein the rest maximum comprises a greatest reading generated by the accelerometer for the period of rest, and
determining the rest threshold based at least in part on the rest maximum;
determine a peak threshold for each of the plurality of time periods with a counted peak height, wherein the peak threshold comprises a weighted average of two or more counted peak heights; and
increment a counter responsive to the counted peak height exceeding the peak threshold associated with the time period in which the counted peak height occurred, wherein a number stored by the counter represents a number of steps taken by the individual.
19. The computer program product of claim 18 , wherein the accelerometer measures linear acceleration along a vertical axis.
20. The computer program product of claim 18 , wherein the computer-readable program code portions, when executed, are further configured to apply a data-smoothing function to the plurality of accelerometer outputs to determine the readings.
21. The computer program product of claim 20 , wherein the data-smoothing function comprises one or more of a low-pass filter, a moving average, or a curve-fitting function.
22. The computer program product of claim 18 , wherein each of the plurality of time periods is of equal duration.
23. The computer program product of claim 18 , wherein determining the rest threshold comprises one or more of:
multiplying the rest maximum by a coefficient greater than or equal to one; or
adding a fixed value to the rest maximum.
24. The computer program product of claim 18 , wherein the two or more counted peak heights are the two or more counted peak heights immediately preceding each time period having a counted peak height.
25. The computer program product of claim 18 , wherein the accelerometer measures linear acceleration along three axes and the plurality of accelerometer outputs from the three axes are combined.