Step counting method and device

• US 10,302,449 B2
• Filed: 12/25/2014
• Issued: 05/28/2019
• Est. Priority Date: 12/31/2013
• Status: Active Grant

• Current Assignee: Goertek Incorporated
• Original Assignee: Goertek Incorporated
• Inventors: Liu, Song, Wang, Fupo, Li, Na
• Primary Examiner(s): Bui, Tha-O H
• Application Number:
  US14/891,581
• Publication Number:
  US 20160298984A1
• Time in Patent Office: 1,615 Days
• Field of Search: 702160
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A63B 2220/17 Counting, e.g. counting periodical movements, revolutions or cycles, or including further data processing to determine distances or speed
• CPC Class Codes: A63B 24/0062 Monitoring athletic performances, e.g. for determining the work of a user on an exercise apparatus, the completed jogging or cycling distance
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

The present invention provides a step counting method and device. The method comprises the following steps performed repeatedly: a) obtaining three monoaxial acceleration signals with a predetermined length from triaxial output of a triaxial acceleration sensor worn on a walkrunner; b) performing high-pass filtering on each obtained monoaxial acceleration signal; c) performing pitch detection on each high-pass filtered monoaxial acceleration signal; d) using the pitch obtained in each pitch detection as a cut-off frequency to set a low-pass or band-pass filter, and performing low-pass or band-pass filtering on corresponding high-pass filtered monoaxial acceleration signal by using it; e) obtaining acceleration signal extreme value points from each low-pass or band-pass filtered monoaxial acceleration signal and removing interfering extreme value points therein; f) counting the number of the acceleration signal extreme value points after the interfering extreme value points have been removed; g) determining the accumulative walkrun step number of the walkrunner. The method can count steps accurately.

Claims

1. A step counting method, wherein the step counting method is performed by using an electronic step counting device worn on a walk runner and comprising a triaxial acceleration sensor, a memory having instructions stored thereon and at least one processor, the method comprises the following steps performed by the at least one processor based on instructions stored on the memory:

obtaining three monoaxial acceleration signals with a predetermined length from triaxial output of the triaxial acceleration sensor;

performing high-pass filtering on each obtained monoaxial acceleration signal;

performing pitch detection on each high-pass filtered monoaxial acceleration signal, to obtain a pitch of each monoaxial acceleration signal;

selecting a lowest pitch in the three monoaxial acceleration signals as a cut-off frequency to set a low-pass or band-pass filter, and performing low-pass or band-pass filtering on each high-pass filtered monoaxial acceleration signal by using the low-pass or band-pass filter;

obtaining acceleration signal extreme value points from each low-pass or band-pass filtered monoaxial acceleration signal and removing interfering extreme value points from the acceleration signal extreme value points;

counting a number of the acceleration signal extreme value points of each low-pass or band-pass filtered monoaxial acceleration signal after the interfering extreme value points have been removed;

determining a walkrun step number obtained from around of step counting based on a result of counting, and calculating an accumulative walkrun step number of the walkrunner.

2. The step counting method according to claim 1, wherein, one or more methods of autocorrelation function method, cepstrum method, linear predictive coding method, and average magnitude difference function method are used in the pitch detection.

3. The step counting method according to claim 2, wherein, the performing pitch detection on each high-pass filtered monoaxial acceleration signal comprises:

performing attenuation process on each high-pass filtered monoaxial acceleration signal by using a filter with which the attenuation of signal energy increases from low frequency to high frequency;

calculating an autocorrelation function ρ

(τ

) of each high-pass filtered monoaxial acceleration signal after the attenuation process by using the following formula;

4. The step counting method according to claim 1, wherein, the removing the interfering extreme value points from the acceleration signal extreme value points comprises:

filtering out the interfering extreme value points from the acceleration signal extreme value points through time gap;

or,

filtering out the interfering extreme value points from the acceleration signal extreme value points through time gap and magnitude value.

5. The step counting method according to claim 4, wherein, the interfering extreme value point comprises such an acceleration signal extreme value point that a time gap between the acceleration signal extreme value point and its previous acceleration signal extreme value point is smaller than a predetermined threshold.

6. The step counting method according to claim 4, wherein, the interfering extreme value points comprise acceleration signal extreme value points, whose magnitude values are not maximal, among the acceleration signal extreme value points in which a time gap between any two adjacent acceleration signal extreme value points is smaller than a predetermined threshold.

7. The step counting method according to claim 1, wherein, the determining a walkrun step number obtained from a round of step counting based on a result of counting comprises:

if energy difference of each monoaxial acceleration signal is less than a predetermined threshold, averaging numbers of the acceleration signal extreme value points corresponding to each monoaxis after the interfering extreme value points have been removed, and taking an average number as the walkrun step number obtained in this round of step counting;

or, if energy difference of each monoaxial acceleration signal is larger than the predetermined threshold, determining the walkrun step number obtained in this round of step counting based on the number of the acceleration signal extreme value points corresponding to a monoaxial acceleration signal with highest energy after the interfering extreme value points have been removed.

8. The step counting method according to claim 1, further comprises:

calculating displacement based on quadratic integral of at least one monoaxial acceleration signal for time.

9. A computer program, comprising program readable codes, when the program readable codes are operated on a server, the server implements the step counting method according to claim 1.

10. A computer readable medium, for storing the computer program according to claim 9.

11. An electronic step counting device, wherein the electric step counting device is worn on a walkrunner and comprises a triaxial acceleration sensor, a memory having instructions stored thereon and at least one processor, the at least one processor performs the following operations based on instructions stored on the memory:

obtaining three monoaxial acceleration signals with a predetermined length from a triaxial output of the triaxial acceleration sensor;

performing high-pass filtering on each monoaxial acceleration signal obtained;

performing pitch detection on each high-pass filtered monoaxial acceleration signal to obtain a pitch of each monoaxial acceleration signal;

selecting a lowest pitch in the three monoaxial acceleration signals as a cut-off frequency to set a low-pass or band-pass filter, and performing low-pass or band-pass filtering on each high-pass filtered monoaxial acceleration signal by using the low-pass or band-pass filter;

obtaining acceleration signal extreme value points from each low-pass or band-pass filtered monoaxial acceleration signal and removing interfering extreme value points therein;

counting a number of the acceleration signal extreme value points of each low-pass or band-pass filtered monoaxial acceleration signal after the interfering extreme value points have been removed;

determining a walkrun step number obtained from a round of step counting based on the result counted, and calculating an accumulative walkrun step number of the walkrunner.

12. The step counting device according to claim 11, wherein, the operation of performing pitch detection on each high-pass filtered monoaxial acceleration signal to obtain a pitch of each monoaxial acceleration signal comprises:

performing attenuation process on each high-pass filtered monoaxial acceleration signal in such a manner that attenuation of signal energy increases from low frequency to high frequency;

calculating an autocorrelation function ρ

(τ

) of a signal output from the attenuation filter by using the following formula;

13. The step counting device according to claim 11, wherein, the operation of determining a walkrun step number obtained from a round of step counting based on the result counted, and calculating an accumulative walkrun step number of the walkrunner comprises:

calculate energy of each monoaxial acceleration signal, and

if energy difference of each monoaxial acceleration signal is less than a predetermined threshold, averaging numbers of the acceleration signal extreme value points corresponding to each monoaxis after the interfering extreme value points have been removed, and taking an average number as the walkrun step number obtained in a around of step counting;

or, if energy difference of each monoaxial acceleration signal is larger than the predetermined threshold, determining the walkrun step number obtained in the round of step counting based on the number of the acceleration signal extreme value points corresponding to a monoaxial acceleration signal with highest energy after the interfering extreme value points have been removed.