Accelerometer-based systems and methods for quantifying steps

• US 10,732,006 B1
• Filed: 12/11/2019
• Issued: 08/04/2020
• Est. Priority Date: 11/03/2014
• Status: Active Grant

• Current Assignee: Savvysherpa, LLC (UnitedHealth Group Incorporated)
• Original Assignee: Savvysherpa, LLC (UnitedHealth Group Incorporated)
• Inventors: Romrell, Gregory R., Brunt, Ryan J. H., Griffith, Jon Benjamin, Roxas, Joseph
• Primary Examiner(s): Betsch, Regis J
• Application Number:
  US16/709,996
• Time in Patent Office: 237 Days
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00

Abstract

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.

Claims

1. A system for counting steps, the system comprising:

a processor in communication with an accelerometer, wherein the accelerometer generates accelerometer outputs from being coupled to an individual; and

a non-transitory computer-readable medium in communication with the processor, the non-transitory computer-readable medium storing instructions for execution by the processor to;

determine a plurality of time periods, each of the plurality of time periods being a time period;

determine readings using the accelerometer outputs;

identify counted peak heights, each of the counted peak heights comprising a maximum reading during a time period in which the maximum reading is greater than a rest threshold, the rest threshold determined by;

receiving readings from the accelerometer during a period of rest,

identifying a rest maximum, the rest maximum comprising the greatest reading generated by the accelerometer during the period of rest, and

determining the rest threshold using the rest maximum;

determine a peak threshold for each of the plurality of time periods having a counted peak height, the peak threshold comprising a first weighted average of two or more counted peak heights;

identify counted amplitudes, each of the counted amplitudes comprising a difference between the maximum reading and a minimum reading during a time period in which the counted peak height exceeds the peak threshold;

determine an amplitude threshold for each of the plurality of time periods having a counted amplitude, the amplitude threshold comprising a second weighted average of two or more counted amplitudes; and

increment a counter if the counted amplitude exceeds the amplitude threshold associated with the time period in which the counted amplitude occurred, a number stored by the counter representing a number of steps taken by the individual.

2. The system of claim 1, wherein the accelerometer measures linear acceleration along a vertical axis.

3. The system of claim 1, wherein the processor applies a data-smoothing function to the accelerometer outputs to determine the readings.

4. The system 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 system of claim 1, wherein each of the plurality of time periods is of equal duration.

6. The system of claim 1, wherein each of the plurality of time periods is measured by a device selected from the group consisting of the processor, the accelerometer, and an electric clock.

7. The system 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.

8. The system of claim 1, 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.

9. The system of claim 1, wherein each of the counted amplitudes comprises a difference between the maximum reading and the minimum reading during a time period in which a function of the counted peak height exceeds the peak threshold, the function comprising one or more of:

multiplying the counted peak height by a coefficient or adding a fixed value to the counted peak height.

10. The system of claim 1, wherein the two or more counted amplitudes are the two or more counted amplitudes immediately preceding each time period having a counted amplitude.

11. The system of claim 1, wherein the system further comprises a display screen in communication with the processor, the display screen displaying information including the number stored by the counter.

12. The system of claim 1, wherein the accelerometer measures linear acceleration along three axes and the accelerometer outputs from the three axes are combined.

13. A method of counting steps from outputs of an accelerometer, the accelerometer coupled to an individual and in communication with a processor, the 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 steps of the method, the method comprising:

determining a plurality of time periods, each of the plurality of time periods being a time period;

determining readings using the outputs of the accelerometer;

identifying counted peak heights, each of the counted peak heights comprising a maximum reading during a time period in which the maximum reading is greater than a rest threshold, the rest threshold determined by;

receiving readings from the accelerometer during a period of rest,

identifying a rest maximum, the rest maximum comprising a greatest reading generated by the accelerometer during the period of rest, and

determining the rest threshold using the rest maximum;

determining a peak threshold for each of the plurality of time periods having a counted peak height, the peak threshold comprising a first weighted average of two or more counted peak heights;

identifying counted amplitudes, each of the counted amplitudes comprising a difference between the maximum reading and a minimum reading during a time period in which the counted peak height exceeds the peak threshold;

determining an amplitude threshold for each of the plurality of time periods having a counted amplitude, the amplitude threshold comprising a second weighted average of two or more counted amplitudes; and

incrementing a counter if the counted amplitude exceeds the amplitude threshold associated with the time period in which the counted amplitude occurred, a number stored by the counter representing a number of steps taken by the individual.

14. The method of claim 13, wherein the processor applies a data-smoothing function to the outputs of the accelerometer to determine the readings.

15. The method of claim 14, wherein the data-smoothing function comprises one or more of a low-pass filter, a moving average, or a curve-fitting function.

16. The method of claim 13, wherein each of the plurality of time periods is of equal duration.

17. The method of claim 13, 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.

18. The method of claim 13, wherein the two or more counted peak heights immediately precede each time period having a counted peak height.

19. The method of claim 13, wherein each of the counted amplitudes comprises a difference between the maximum reading and the minimum reading during a time period in which a function of the counted peak height exceeds the peak threshold, the function comprising one or more of:

multiplying the counted peak height by a coefficient;

or

adding a fixed value to the counted peak height.

20. The method of claim 13, wherein the two or more counted amplitudes immediately precede each time period having a counted amplitude.

21. A computer program product for counting steps from accelerometer outputs, the accelerometer 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, configured to:

determine a plurality of time periods, each of the plurality of time periods being a time period;

determine readings using the accelerometer outputs;

identify counted peak heights, each of the counted peak heights comprising a maximum reading during a time period in which the maximum reading is greater than a rest threshold, the rest threshold determined by;

receiving readings from the accelerometer during a period of rest,

identifying a rest maximum, the rest maximum comprising the greatest reading generated by the accelerometer during the period of rest, and

determining the rest threshold using the rest maximum;

determine a peak threshold for each of the plurality of time periods having a counted peak height, the peak threshold comprising a first weighted average of two or more counted peak heights;

identify counted amplitudes, each of the counted amplitudes comprising a difference between the maximum reading and a minimum reading during a time period in which the counted peak height exceeds the peak threshold;

determine an amplitude threshold for each of the plurality of time periods having a counted amplitude, the amplitude threshold comprising a second weighted average of two or more counted amplitudes; and

increment a counter if the counted amplitude exceeds the amplitude threshold associated with the time period in which the counted amplitude occurred, a number stored by the counter representing a number of steps taken by the individual.