Multi-band pedometer with mobility mode indicator

Patent metadata

Field	Value
Publication number	US-10018481-B1
Application number	US-201414502168-A
Country	US
Kind code	B1
Filing date	Sep 30, 2014
Priority date	Sep 30, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A system and method for reliably counting user steps. Various aspects may, for example, comprise processing a plurality of frequency bands of at least one sensor signal to accurately count user steps. A plurality of filtered sensor signals may be formed by filtering a sensor signal with a plurality of band-pass filters from which a dominant filtered sensor signal may be selected. The selected dominant filtered sensor signal may then be used to count user steps. Further, a frequency band of a sensor signal may be selected such that if it is determined the user is not engaged in a non-stepping activity, user steps may be counted using the content of the signal in the selected frequency band. Still further, user steps may be counted using an identified dominant harmonic.

First claim

What is claimed is:

1. A pedometer system comprising: a sensor, a plurality of band-pass filters, and at least one module operable to, at least: receive a signal from the sensor; form a plurality of filtered sensor signals by, at least in part, filtering the received sensor signal with each of the plurality of band-pass filters; select a dominant filtered sensor signal from the plurality of filtered sensor signals; and count user steps based, at least in part, on the selected dominant filtered sensor signal, wherein the at least one module is operable to select a dominant filtered sensor signal by, at least in part: determining a respective indication of energy for each of the plurality of filtered sensor signals; selecting as the dominant filtered sensor signal the filtered sensor signal of the plurality of filtered sensor signals with the highest respective indication of energy; and adapting a relation between a rate at which the user steps are counted and a frequency of the selected dominant filtered sensor signal by counting user steps at twice a primary frequency of the dominant filtered sensor signal when the dominant filtered sensor signal is a first of the plurality of filtered sensor signals and counting user steps at a primary frequency of the dominant filtered sensor signal when the dominant filtered sensor signal is a second of the plurality of filtered sensor signals.

2. The pedometer system of claim 1 , wherein the at least one module is operable to determine whether a threshold number of steps have occurred, and increment a step count only after the threshold number of steps have occurred.

3. The pedometer system of claim 1 , wherein the at least one module is operable to determine whether a threshold number of steps have occurred, and select a dominant filtered sensor signal only after the threshold number of steps have occurred.

4. The pedometer system of claim 1 , wherein the at least one module is operable to determine a cadence, and count user steps based, at least in part, on the determined cadence.

5. The pedometer system of claim 4 , wherein the at least one module is operable to identify a missed step based, at least in part, on the determined cadence.

6. The pedometer system of claim 1 , wherein the at least one module is operable to count user steps by, at least in part, detecting zero crossings of the dominant filtered sensor signal that are associated with signal swings of at least a threshold magnitude.

7. The pedometer system of claim 6 , wherein the at least one module is operable to count user steps by, at least in part, comparing a time of a detected zero crossing to an expected time for a zero crossing.

8. The pedometer system of claim 1 , wherein determining a respective indication of energy for each of the plurality of filtered sensor signals comprises filtering a respective amplitude of each of the plurality of filtered sensor signals with a respective Infinite Impulse Response (IIR) filter.

9. The pedometer system of claim 1 , wherein the received sensor signal comprises an accelerometer 2-axis signal expressed in a world coordinate system.

10. The pedometer system of claim 9 , wherein the at least one module is operable to receive the sensor signal from a sensor fusion module that converts an accelerometer signal expressed in a body coordinate system to an accelerometer signal expressed in the world coordinate system.

11. A pedometer system comprising: a sensor, a plurality of filters, and at least one module operable to, at least: receive a signal from the sensor; select a frequency band of the received sensor signal; determine if the user is engaged in a non-stepping activity; and if the user is not engaged in a non-stepping activity, then count user steps based, at least in part, on the received signal in the selected frequency band, such that a relation between a rate at which the user steps are counted and a frequency of the selected frequency band is adapted so that user steps are counted at twice a primary frequency of a dominant filtered sensor signal when the dominant filtered sensor signal is a first of a plurality of filtered sensor signals and user steps are counted at a primary frequency of the dominant filtered sensor signal when the dominant filtered sensor signal is a second of the plurality of filtered sensor signals, wherein the at least one module is operable to determine if the user is engaged in a non-stepping activity by, at least in part, forming a first filtered sensor signal by, at least in part, filtering the received sensor signal with a first filter, determining a first indication of energy for the first filtered sensor signal, forming a second filtered sensor signal by, at least in part, filtering the received sensor signal with a second filter; determining a second indication of energy for the second filtered sensor signal and comparing the first indication of energy to the second indication of energy to discriminate between stepping activity and non-stepping activity.

12. The pedometer system of claim 11 , wherein the non-stepping activity comprises vehicle travel.

13. The pedometer system of claim 11 , wherein the at least one module is operable to determine if the user is engaged in a non-stepping activity by, at least in part, analyzing a signal received from an activity classifier module.

14. A pedometer system comprising: a sensor, a plurality of band-pass filters, and at least one module operable to, at least: receive a signal from the sensor that comprises a plurality of harmonics; analyze the harmonics to identify a dominant harmonic by determining a respective indication of energy for each of the plurality of harmonics and selecting as the dominant harmonic the harmonic with the highest respective indication of energy; and count user steps based, at least in part, on the selected dominant harmonic, wherein a relation between a rate at which the user steps are counted and a frequency of the selected dominant harmonic is adapted by counting user steps at twice a primary frequency of the dominant filtered sensor signal when the dominant filtered sensor signal is a first of the plurality of filtered sensor signals and counting user steps at a primary frequency of the dominant filtered sensor signal when the dominant filtered sensor signal is a second of the plurality of filtered sensor signals.

15. The pedometer system of claim 14 , wherein the second of the plurality of harmonics is a default dominant harmonic.

Assignees

• Invensense Inc
• Worldwise Inc

Inventors

• Shekhar Hemabh
• Srivastava Dhruv
• Lin Shang Hung
• Saha Sankalita

Classifications

• G01C22/006 Primary

  Pedometers · CPC title