METHOD, APPARATUS, COMPUTER PROGRAM AND SYSTEM FOR MEASURING OSCILLATORY MOTION

• US 20130172769A1
• Filed: 05/16/2011
• Published: 07/04/2013
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: The University Court Of The University Of Edinburgh
• Original Assignee: University of Edinburgh
• Inventors: Arvind, Damal, Bates, Andrew
• Granted Patent: US 9,724,019 B2
• Time in Patent Office: Days
• US Class Current: 600/534
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/0223 Magnetic field sensors
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: G01H 1/00 Measuring characteristics of vibrations in solids by using direct conduction to the detector G01H9/00, G01H11/00 take precedence

Abstract

A method, apparatus, computer program, system and device for measuring oscillatory motion comprising: receiving a plurality of signals related to a plurality of measurements of a direction of a vector parameter (a_t-1, a_t); determining a predominant measured direction of the vector parameter (ā_t) based on the plurality of measurements of the direction of the vector parameter; determining an angle of rotation (φ_t) between: a measured direction of the vector parameter (a_t) of one of the plurality of measurements of the direction of the vector parameter, and the predominant measured direction of the vector parameter (ā_t).

Claims

1. A method for measuring oscillatory motion comprising:

receiving a plurality of signals related to a plurality of measurements of a direction of a vector parameter;

determining a predominant measured direction of the vector parameter based on the plurality of measurements; and

determining an angle of rotation between;

a measured direction of the vector parameter of one of the plurality of measurements, and

the predominant measured direction of the vector parameter.

2. A method as claimed in any previous claim, wherein the plurality of measurements comprises a plurality of pairs of sequential measurements of a direction of the vector parameter;

the method further comprising;

determining an of axis of rotation for each pair of sequential measurements, wherein the axis of rotation is defined as an axis about which the measured direction of the vector parameter rotates between a pair of sequential measurements of the direction of the vector parameter;

determining a predominant axis of rotation based on the determined axes of rotation; and

wherein the angle of rotation is further determined based on rotation about the predominant axis of rotation.

3. A method as claimed in any previous claim, further comprising determining an angular velocity based on the angle of rotation.

4. A method as claimed in any previous claim, wherein the signals related to a measurement of a direction of the vector parameter are received from at least one sensor coupled to an object whose oscillatory motion is to be measured.

5. A method as claimed in claim 4, wherein the object is a body part.

6. A method as claimed in any previous claim, wherein the vector parameter comprises at least one of:

gravitational field, magnetic field and angular orientation.

7. A method as claimed in any previous claim, wherein each signal related to a measurement of a direction of the vector parameter comprises a representation of the direction of the vector parameter in three orthogonal axes.

8. A method as claimed in any previous claim, wherein at least one of:

receiving the plurality of signals related to the plurality of measurements of the direction of the vector parameter,

determining the predominant direction of the measured vector parameter, or

determining the predominant axis of rotation;

occurs over a predetermined period of time.

9. A method as claimed in any previous claim, wherein the predetermined period of time is greater than or equal to the duration of a cycle of the oscillatory motion.

10. A method as claimed in any previous claim, further comprising determining a change between:

a measurement of the vector parameter and

a sequential measurement of the vector parameter.

11. A method as claimed in previous claim 10, further comprising determining if the change is greater than a threshold value;

and

if the change is greater than a threshold value;

receiving a further plurality of signals related to a plurality of measurements of a direction of the vector parameter;

re-determining the predominant direction of the vector parameter based on the further plurality of measurements; and

determining an angle of rotation between;

a measured direction of the vector parameter of one of the further plurality of measurements of the direction of the vector parameter, and

the re-determined predominant direction of the vector parameter.

12. A method as claimed in any previous claim, further comprising:

determining a plurality of angular velocities;

monitoring values of angular velocities;

defining a first band of range of angular velocity values where an angular velocity value is greater that a first threshold value;

defining a second band of range of angular velocity values where an angular velocity value is less than a second threshold value;

defining a third band of range of angular velocity values where an angular velocity value is between the first and second threshold values; and

registering a count of a cycle of the oscillatory motion upon determining monitored values of angular velocity undergoing 4 band transitions.

13. A method as claimed in any previous claim, further comprising:

receiving a plurality of signals related to a plurality of measurements of a direction of second vector parameter;

determining a predominant direction of the second vector parameter based on the plurality of measurements of the direction of the second vector parameter; and

determining an angle of rotation between;

a measured direction of the second vector parameter and

the predominant direction of the second vector parameter.

14. A method as claimed in previous claim 13, wherein the second vector parameter differs from the vector parameter.

15. A method as claimed in any previous claim, further comprising determining an angle of projection, wherein the angle of projection is defined as a projection of the angle of rotation onto a surface.

16. A method as claimed in previous claim 15, wherein the surface comprises one of a plane or at least part of an ellipsoid.

17. A method as claimed in claim 3, further comprising:

determining a series of values of angular velocities or angles of rotation; and

applying a pattern recognition algorithm to the series of values of angular velocities or angles of rotation.

18. A method as claimed in claim 17, further comprising applying a pattern recognition algorithm to the series of values of angular velocities or angles of rotation in order to identify a motion.

19. A method as claimed in claim 18, further comprising:

generating a control signal in response to identification of the motion.

20. An apparatus for measuring oscillatory motion comprising:

a memory storing computer program instructions; and

a processor configured to execute the computer program instructions to cause the apparatus at least to perform the method of any of claims 1 to 19.

21. A computer program that, when run on a computer, performs the method of any of claims 1 to 19.

22. A carrier signal carrying the computer program as claimed in claim 21.

23. A computer readable storage medium encoded with instructions that, when executed by a processor, performs the method of any of claims 1 to 19.

26. A system for measuring oscillatory motion comprising:

means for measuring a direction of a vector parameter;

means for generating a signal related to the direction of a vector parameter;

means for transmitting the signal; and

the apparatus according to any of claims 20 and 24 to 25.

27. A device for measuring oscillatory motion comprising:

means for measuring a direction of a vector parameter;

means for generating a signal related to the direction of a vector parameter;

means for transmitting the signal; and

the apparatus according to any of claims 20 and 24 to 25.

28. A system as claimed in claim 26 or a device as claimed in claim 27, wherein the means for measuring the direction of the vector parameter is arranged to be coupled to a body part.

29. A system as claimed in claim 26 or a device as claimed in claim 27, wherein the means for measuring the direction of the vector parameter comprises at least one of:

means for measuring a gravitational field,

means for measuring a magnetic field, and

means for measuring angular orientation.

30. A system as claimed in claim 26 or a device as claimed in claim 27, wherein the means for measuring the direction of the vector parameter is arranged to measure the direction of the vector parameter in three dimensions.

24. An apparatus for measuring oscillatory motion comprising:

means for receiving a plurality of signals related to a plurality of measurements of a direction of a vector parameter;

means for determining a predominant direction of the vector parameter based on the plurality of measurements; and

means for determining an angle of rotation between;

a measured direction of the vector parameter of one of the plurality of measurements, and

the predominant measured direction of the vector parameter.

25. An apparatus for measuring oscillatory motion comprising:

an input interface arranged to receive a plurality of signals related to a plurality of measurements of a direction of a vector parameter;

a controller arranged to determine a predominant direction of the vector parameter based on the plurality of measurements; and

the controller further arranged to determine an angle of rotation between;

a measured direction of the vector parameter of one of the plurality of measurements, and

the predominant measured direction of the vector parameter.

31. A method, apparatus, computer program, system and device for measuring oscillatory motion substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.