Apparatus and method for counting exercise repetitions

• US 7,877,226 B2
• Filed: 03/03/2008
• Issued: 01/25/2011
• Est. Priority Date: 03/03/2008
• Status: Expired due to Fees

• Current Assignee: IDT Technology Limited (IDT International Limited)
• Original Assignee: IDT Technology Limited (IDT International Limited)
• Inventors: Chan, Raymond, Li, Li, Leong, Mun Hoong
• Primary Examiner(s): Wachsman; Hal D
• Application Number:
  US12/041,645
• Publication Number:
  US 20090221403A1
• Time in Patent Office: 1,058 Days
• Field of Search: 702/66, 702/141, 702/160, 702/187
• US Class Current: 702/160
• CPC Class Codes: A63B 2071/0661 arranged on the user
• CPC Class Codes: A63B 21/06 User-manipulated weights
• 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 2220/40 Acceleration
• CPC Class Codes: A63B 2220/836 Sensors arranged on the body of the user
• CPC Class Codes: A63B 2244/20 Swimming
• 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: A63B 5/20 Skipping-ropes or similar devices rotating in a vertical plane
• CPC Class Codes: A63B 69/0028 for running, jogging or speed-walking movable endless bands A63B22/02
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

An apparatus and method for counting exercise repetitions are provided for counting exercise repetition even when an exerciser attaches the apparatus in different places and along different orientations of his or her body. The apparatus and method utilizes acceleration data along at least three axes and determines that a valid step is taken by the exerciser if at least one of acceleration profiles falls within at least one of pre-defined thresholds. Moreover, a method of identifying an optimal axis for exercise repetition measurement is disclosed by comparing the acceleration profiles of previous steps with amplitude, cycle and rhythm thresholds.

Claims

1. An apparatus for counting exercise repetitions comprising

a) three accelerometers simultaneously measuring acceleration data of an exerciser along three different directions to obtain acceleration profiles;

each said acceleration profile further comprising an amplitude movement and an acceleration cycle along said direction; and

b) a data processing unit executing a counting procedure to increment a repetition count if said amplitude movement in at least one said acceleration profile falls within a first amplitude threshold and said acceleration cycle in the same said acceleration profile falls within a first cycle threshold;

wherein said apparatus counts said exercise repetitions of said exerciser irrespective of an orientation of said apparatus.

2. The apparatus of claim 1, wherein each of said three accelerometers measure acceleration along one of three orthogonal axes in three dimensional spaces.

3. The apparatus of claim 2 wherein each said acceleration profile further comprises a rhythm that is judged from the repetitive steps of said exerciser;

and an optimal axis for counting exercise repetition is identified, said optimal axis being the axis where said amplitude movement, acceleration cycle and rhythm in said acceleration profile of said axis satisfy a second amplitude threshold, a second cycle threshold and a first rhythm threshold respectively.

4. The apparatus of claim 1, wherein said first amplitude threshold and said first cycle threshold are computed from average values of said acceleration data along said direction.

5. The apparatus of claim 1, wherein said repetition count is incremented by two when said amplitude movement falls within said first amplitude threshold and said acceleration cycle is longer than one times said first cycle threshold but shorter than two times said first cycle threshold.

6. The apparatus of claim 1, wherein said apparatus enters sleeping mode if no repetition is counted within a predetermined duration of time.

7. The apparatus of claim 1, wherein said apparatus is a pedometer.

8. The apparatus of claim 1, wherein said apparatus is a swim stroke counter that counts a number of swimming strokes of said exerciser.

9. The apparatus of claim 1, wherein said apparatus is an exercise event counter that counts a number of exercise events that said exerciser completes.

10. A method of counting exercise repetitions comprising the steps of

a) simultaneously measuring acceleration data of an exerciser along at least three axes by at least three accelerometers to obtain acceleration profiles;

each said acceleration profile further comprising an amplitude movement and an acceleration cycle along said axes;

b) comparing said acceleration profile on each said axis with a first amplitude threshold and a first cycle threshold using a data processing unit; and

c) adding to a repetition count if said amplitude movement in at least one said acceleration profile falls within a first amplitude threshold and said acceleration cycle in the same said acceleration profile falls within a first cycle threshold.

11. The method of claim 10, wherein said acceleration profiles comprise repetitive waveforms and said first amplitude threshold and said first cycle threshold are computed from said acceleration data along said axis.

12. The method of claim 10, wherein said repetition count is incremented by two when said amplitude movement falls within said first amplitude threshold and said acceleration cycle is longer than one times said first cycle threshold but shorter than two times said first cycle threshold.

13. The method of claim 10, wherein said acceleration profiles further comprises a rhythm that is judged from the repetitive steps of said exerciser;

and said comparing step identifies an optimal axis for comparison, said optimal axis being the axis where said amplitude movement, acceleration cycle and rhythm in said acceleration profile of said optimal axis satisfy a second amplitude threshold, a second cycle threshold and a first rhythm threshold respectively.

14. A method of identifying a new optimal axis against a previous optimal axis for counting exercise repetitions comprising

a) simultaneously measuring the acceleration of an exerciser along at least three axes by at least three accelerometers to obtain acceleration profiles;

each said acceleration profile further comprising an amplitude movement and an acceleration cycle along said axes;

b) detecting a first valid repetition along a first axis by a data processing unit when said amplitude movement of said acceleration profile on said first axis satisfies a first amplitude threshold range and said acceleration cycle of said same acceleration profile satisfies a first cycle threshold range first before the other axes;

c) if said first axis is different from said previous optimal axis, computing a first amplitude indicator, a first cycle indicator and a first rhythm indicator from said first axis, and a second amplitude threshold, a second cycle threshold range and a rhythm threshold range from said previous optimal axis using said data processing unit;

d) identifying said first axis as said new optimal axis using said data processing unit when said first amplitude indicator satisfies said second amplitude threshold;

said first cycle indicator is within said second cycle threshold range and said first rhythm indicator is within said rhythm threshold range.

15. The method of claim 14, wherein said first amplitude indicator is calculated from the ratios of amplitudes and cycles of a predetermined number of previous repetitions on said first axis;

said second amplitude threshold is calculated from the ratios of amplitudes and cycles of a predetermined number of previous repetitions on said second axis;

said first cycle indicator is calculated from the cycles of said predetermined number of previous repetitions on said first axis; and

said second cycle threshold range is calculated from the cycles of said predetermined number of previous repetitions on said second axis.

16. The method of claim 14, wherein said first rhythm indicator is calculated from the mean of absolute differences between cycles of a first predetermined number of previous repetitions and the mean value thereof on said first axis;

and said rhythm threshold range is calculated from the mean of absolute differences between cycles of a second predetermined number of previous repetitions and the mean value thereof on said second axis.

17. The method of claim 14 wherein said new optimal axis replaces said previous optimal axis.