Determining a speed of a multidimensional motion in a global coordinate system

Patent metadata

Field	Value
Publication number	US-10188903-B2
Application number	US-201314760419-A
Country	US
Kind code	B2
Filing date	Jan 18, 2013
Priority date	Jan 18, 2013
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

Embodiments relate to determining a speed of a multidimensional motion of an athlete in a global coordinate system based on multidimensional acceleration data from a multidimensional accelerometer placed at a movable limb of the athlete, the movable limb being at least one of translatory and rotatable, and the movable limb defining a local coordinate system. Based on the multidimensional acceleration data, at least one correction quantity may be determined taking into account a rotation of the local coordinate system relative to the global coordinate system during the multidimensional motion. The speed of the multidimensional motion may be determined based on an integration of the multidimensional acceleration data and in consideration of the at least one correction quantity.

First claim

The invention claimed is:

1. A method for determining a speed of a multidimensional motion of an athlete in a global coordinate system based on multidimensional acceleration data from a multidimensional accelerometer placed at a movable limb of the athlete, the movable limb being at least one of translatory and rotatable, and the movable limb defining a local coordinate system, the method comprising:
determining, based on the multidimensional acceleration data, at least one correction quantity taking into account a rotation of the local coordinate system relative to the global coordinate system during the multidimensional motion; and
determining the speed of the multidimensional motion based on an integration of the multidimensional acceleration data and in consideration of the at least one correction quantity; and
detecting at least one of the multidimensional motion and a period of motion inactivity based on at least one of (i) detecting an excess of an acceleration threshold using the multidimensional acceleration data, (ii) detecting a saturation of one or more dimensions of the multidimensional acceleration data, and (iii) detecting an oscillation of the multidimensional acceleration data.

2. The method according to claim 1 , wherein
the athlete is a boxer wearing at least one boxing glove,
the multidimensional motion is a multidimensional punch of the boxer, and
the multidimensional accelerometer is placed at the at least one boxing glove.

3. The method according to claim 1 , wherein the determining the at least one correction quantity comprises:
comparing a first speed of an athlete's motion against a second speed of the athlete's motion, the first speed of the athlete's motion being obtained based on an integration of the multidimensional acceleration data for the athlete's motion without the at least one correction quantity, and the second speed of the athlete's motion obtained based on reference motion data leading to more accurate speed results than the multidimensional acceleration data; and
determining a scalar correction quantity based on the comparison.

4. The method according to claim 3 , wherein the reference motion data is obtained based on a video or real-time locating system based analysis of motion of a reference athlete during an initial training phase of the method.

5. The method according to claim 4 , wherein the determining the at least one correction quantity further comprises:
determining a scaling factor based on a relation of an actual anatomical size of the athlete to an anatomical size of the reference athlete.

6. The method according to claim 1 , wherein
the multidimensional accelerometer comprises three 3-axis-accelerometers spatially distributed at the movable limb; and
the determining the at least one correction quantity includes
determining, based on the multidimensional acceleration data of the three 3 axis-accelerometers, the rotation of the local coordinate system relative to the global coordinate system during movement of the athlete in order to computationally compensate for the rotation by a corresponding coordinate transformation of the local coordinate system.

7. The method according to claim 6 , wherein the rotation of the local coordinate system is determined via two-fold integration of a difference between first acceleration data from a first accelerometer and second acceleration data from a second accelerometer of the three 3-axis-accelerometers.

8. The method according to c claim 1 , wherein
the athlete further includes at least one magnetic field sensor; and
the determining the at least one correction quantity includes
determining a spatial orientation of the movable limb via measuring a change of a static magnetic field surrounding the movable limb via the at least one magnetic field sensor; and

the change is due to the multidimensional motion in the static magnetic field.

9. The method according to claim 8 , wherein the static magnetic field is an artificially generated homogeneous magnetic field.

10. The method according to claim 1 , wherein the determining the at least one correction quantity comprises:
estimating the rotation of the local coordinate system based on the multidimensional acceleration data.

11. The method according to claim 1 , further comprising:
calibrating the multidimensional acceleration data by taking into account acceleration due to gravity.

12. The method according to claim 11 , wherein the calibrating the multidimensional acceleration data comprises:
selecting at least one multidimensional acceleration data vector for a period of motion inactivity before a detected motion of the athlete; and
determining the speed of the multidimensional motion based on the integration of the multidimensional acceleration data taking into account said at least one multidimensional acceleration data vector or an average value thereof.

13. The method according to claim 1 , wherein the detecting at least one of the multidimensional motion and a period of motion inactivity is based on the detecting the excess of the acceleration threshold for an amount of time.

14. The method according to claim 1 , wherein the detecting at least one of the multidimensional motion and a period of motion inactivity comprises:
determining an end of the multidimensional motion by detecting a point of saturation of the one or more dimensions of the multidimensional acceleration data under the premise that the multidimensional acceleration data has not been in saturation or above a threshold for a first time interval before said point of saturation; and
determining a beginning of said multidimensional motion by performing a reverse search from the point of saturation until a minimum average value of acceleration is detected in the multidimensional acceleration data.

15. The method according to claim 1 , further comprising:
storing at least one of the multidimensional acceleration data and the determined speed; and
post processing the stored at least one of the multidimensional acceleration data and the determined speed for motion analysis.

16. The method according to claim 1 , further comprising:
displaying information indicative of the determined speed.

17. A computer program product including a non-transitory computer readable medium having computer readable program code embodied therein, wherein the computer readable program code, when loaded on a computer, a processor, or a programmable hardware component, causes the computer, processor or programmable hardware component to implement a method for determining a speed of a multidimensional motion of an athlete in a global coordinate system based on multidimensional acceleration data from a multidimensional accelerometer placed at a movable limb of the athlete, the movable limb being at least one of translatory and rotatable, and the movable limb defining a local coordinate system, the method comprising:
determining, based on the multidimensional acceleration data, at least one correction quantity taking into account a rotation of the local coordinate system relative to the global coordinate system during the multidimensional motion;
determining the speed of the multidimensional motion based on an integration of the multidimensional acceleration data and in consideration of the at least one correction quantity; and
detecting at least one of the multidimensional motion and a period of motion inactivity based on at least one of (i) detecting an excess of an acceleration threshold using the multidimensional acceleration data, (ii) detecting a saturation of o

Assignees

• Fraunhofer Ges Forschung
• Fraunhofer Ges Forschung

Inventors

• Hadaschik Niels
• Kemeth Ferdinand
• Schaefer Matthias
• Von Der Gruen Thomas

Classifications

• A63B24/0006 Primary

  Computerised comparison for qualitative assessment of motion sequences or the course of a movement · CPC title

• G01B7/004

  for measuring coordinates of points · CPC title

• G01P15/00

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• G06K9/00342

  Physics · mapped topic

• G01P7/00 Primary

  Measuring speed by integrating acceleration (measuring travelled distance by double integration of acceleration G01C21/16) · CPC title