METHOD AND DEVICE FOR COUNTING STEPS

• US 20170003140A1
• Filed: 12/23/2014
• Published: 01/05/2017
• Est. Priority Date: 12/31/2013
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation), Movea
• Original Assignee: Energies Alternatives Commissariat A L'Energie Atomique et AUX, Movea
• Inventors: VILLIEN, Christophe
• Granted Patent: US 10,408,637 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 21/14 by recording the course traversed by the object G01C21/16 takes precedence
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

A step detection method comprises the following steps: a) based on at least one signal coming from at least one motion sensor rigidly attached to a portable device, detect events suitable to correspond to steps of a user carrying the portable device; b) based on at least one signal, or on at least one signal coming from another sensor also rigidly attached to the portable device, identify intervals of time during which the device is being manipulated; and c) identify as steps those, from amongst the events detected, which do not coincide with the intervals of time. A device for the implementing such a method, a mobile telephone and touchscreen tablet comprising such a device are also provided.

Claims

1. A step detection method comprising the following steps:

a) based on at least one signal coming from at least one motion sensor rigidly attached to a portable device, detect events suitable to correspond to steps of a user carrying said portable device;

b) based on said or on at least one said signal, or on at least one signal coming from another sensor also rigidly attached to said portable device, identify intervals of time during which said device is being manipulated; and

c) identify as steps those, from amongst the events detected, which do not coincide with said intervals of time;

wherein said step c) comprises a re-synchronization operation between the events detected during said step a) and the intervals of time during which said device is being manipulated, identified during said step b), said re-synchronization operation comprising a compensation for the differences between the latencies of said steps a) and b).

2. The method of claim 1, wherein said step a) comprises the following sub-steps:

a1) acquire three signals representative of three non-coplanar components of said acceleration to which said portable device is subjected;

a2) detect said events using said three signals, by detection and thresholding of local maxima of a fundamental spectral component of a quantity chosen from between the norm of the acceleration to which said portable device is subjected and the projection of said acceleration onto a vertical axis.

3. The method of claim 2, wherein said sub-step a2) comprises the calculation of said norm of the acceleration to which said portable device is subjected based on said acquired signal or signals and its bandpass filtering.

4. The method of claim 2, wherein said sub-step a2) comprises the calculation of said projection onto said vertical axis of the acceleration to which said portable device is subjected based on said acquired signal or signals and its bandpass filtering.

5. The method of claim 3, wherein said bandpass filtering comprises a passband of width not greater than 1 Hz and having a central frequency in the range between 1 Hz and 2 Hz.

6. The method of claim 2, wherein said sub-step a2) comprises a said detection of local maxima by comparison between three successive samples of a signal representative of the fundamental spectral component of the norm, or of the projection onto a vertical axis, of said acceleration, and wherein, after the detection of a local maximum, another local maximum can only be detected after said signal has fallen below a threshold referred to as lower threshold.

7. The method of claim 2, wherein said sub-step a2) comprises an adaptive thresholding of said local maxima.

8. The method of claim 2, wherein, during said step b), said intervals of time during which said device is being manipulated are also detected using said three signals representative of three non-coplanar components of said acceleration to which said portable device is subjected.

9. The method of claim 1, wherein said step b) comprises the following sub-steps:

b1) determine, at a succession of moments in time, the orientation of the vertical direction in a reference frame attached to said portable device;

b2) calculate, for each said moment in time, the angle formed by the orientation of said vertical direction in said reference frame and a reference orientation;

b3) detect a manipulation when said angle exceeds a first threshold; and

b4) subsequent to the detection of a said manipulation, consider that it is in progress for a given period of time.

10. The method of claim 8, wherein said step b) also comprises the following sub-step:

b3′

) detect a manipulation also when said angle exceeds a second threshold, lower than said first threshold, a manipulation being already considered as in progress.

11. The method of claim 9, wherein said step b) also comprises the following sub-step:

b5) when a manipulation is detected at a time called detection time, take as new reference orientation the orientation of said vertical direction at said detection time.

12. The method of claim 9, wherein, during said step b), said reference orientation is chosen to be equal to the orientation of said vertical direction at a preceding time, preceding a current moment in time with a duration τ

in the range between 0.5 and 5 seconds.

13. The method of claim 1, wherein said step c) also comprises an operation of extending said intervals of time before the moment of their detection.

14. The method of claim 1 also comprising a step d) of measuring a repetition frequency of the detected steps.

15. A step detection device comprising:

at least one motion sensor, rigidly attached to a portable device; and

a processor connected to said sensor for receiving at its input at least one signal coming from it, said processor being configured or programmed for implementing a step detection method comprising the following steps;

a) based on at least one signal coming from the motion sensor, detect events suitable to correspond to steps of a user carrying said portable device;

b) based on said or on at least one said signal, or on at least one signal coming from another sensor also rigidly attached to said portable device, identify intervals of time during which said device is being manipulated; and

c) identify as steps those, from amongst the events detected, which do not coincide with said intervals of time;

wherein said step c) comprises a re-synchronization operation between the events detected during said step a) and the intervals of time during which said device is being manipulated, identified during said step b), said re-synchronization operation comprising a compensation for the differences between the latencies of said steps a) and b).

17. A mobile telephone comprising a device according to claim 15.

18. A touchscreen tablet comprising a device according to claim 15.

16. The device of claim 16, wherein said or at least one said motion sensor is a three-axis accelerometer.