Method, apparatus, computer program and system for measuring oscillatory motion

• US 9,724,019 B2
• Filed: 05/16/2011
• Issued: 08/08/2017
• 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
• Primary Examiner(s): Cheng, Jacqueline
• Assistant Examiner(s): PORTILLO, JAIRO H
• Application Number:
  US13/702,014
• Publication Number:
  US 20130172769A1
• Time in Patent Office: 2,276 Days
• Field of Search: None
• 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 comprising:

receiving a plurality of signals from at least one sensor sensing oscillatory motion, the plurality of signals being related to a plurality of measurements of a direction of a vector parameter, wherein the at least one sensor is either directly or indirectly coupled to a body part that undergoes oscillatory motion during respiration;

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

determining a plurality of angles of rotation between;

individual measured directions of the vector parameter of corresponding ones of the plurality of measurements, and

the predominant measured direction of the vector parameter;

determining a plurality of angular velocities based on the plurality of angles of rotation;

monitoring values of the angular velocities;

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

registering a count of a cycle of oscillatory motion upon determining monitored values of angular velocity undergoing four band transitions; and

determining, based on the angular velocities with reference to (i) a predetermined relationship between angular velocity values and cannula pressure values, and (ii) a predetermined relationship between the cannula pressure values and flow rate values for nasal breathing, one or more of;

a respiration pressure, a respiration flow rate, or an inspiratory flow.

2. The method as recited in claim 1, wherein the plurality of measurements comprise a plurality of pairs of sequential measurements of a direction of the vector parameter;

the method further comprising;

determining an 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 an individual angle of rotation of the plurality of angles of rotation is further determined based on rotation about the predominant axis of rotation.

3. The method as recited in claim 1, further comprising determining, based on an individual angular velocity of the plurality of angular velocities, a change in volume of a user'"'"'s chest.

4. An apparatus 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 claim 1.

5. A non-transitory computer readable storage medium encoded with instructions that, when executed by a processor, performs the method of claim 1.

6. The method as recited in claim 1, further comprising determining a change between:

a measurement of the vector parameter, and

a sequential measurement of the vector parameter.

7. The method as recited in claim 6, 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 further plurality of measurements of a direction of the vector parameter;

re-determining the predominant measured 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 measured direction of the vector parameter.

8. The method as recited in claim 1, further comprising:

receiving a plurality of signals related to a plurality of measurements of a direction of a 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.

9. The method as recited in claim 8, wherein the second vector parameter differs from the vector parameter.

10. The method as recited in claim 1, further comprising determining an angle of projection, wherein the angle of projection is defined as a projection of an individual angle of rotation of the plurality of angles of rotation onto a surface.

11. The method as recited in claim 10, wherein the surface comprises one of a plane or at least part of an ellipsoid.

12. The method as recited in claim 1, 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.

13. The method as recited in claim 12, further comprising applying the pattern recognition algorithm to the series of values of angular velocities or angles of rotation in order to identify a motion.

14. The method as recited in claim 13, further comprising generating a control signal in response to identification of the motion.

15. An apparatus comprising:

an input interface configured to receive a plurality of signals from at least one sensor for sensing oscillatory motion, the plurality of signals being related to a plurality of measurements of a direction of a vector parameter, wherein in use the at least one sensor is either directly or directly coupled to a body part that undergoes oscillatory motion during respiration; and

a controller configured to;

determine a predominant direction of the vector parameter based on the plurality of measurements;

determine a plurality of angles of rotation between;

individual measured directions of the vector parameter of corresponding ones of the plurality of measurements, and

the predominant direction of the vector parameter;

determine a plurality of angular velocities based on the plurality of angles of rotation;

monitor values of the angular velocities;

define a first band of range of angular velocity values where an angular velocity value is greater than a first threshold value;

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

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

register a count of a cycle of oscillatory motion upon determining monitored values of angular velocity undergoing four band transitions; and

determine, based on the angular velocities with reference to (i) a predetermined relationship between angular velocity values and cannula pressure values, and (ii) a predetermined relationship between the cannula pressure values and flow rate values for nasal breathing, one or more of;

a respiration pressure, a respiration flow rate, or an inspiratory flow.

16. A system comprising:

a sensor configured to measure a direction of a vector parameter;

a processor configured to generate a signal related to the direction of the vector parameter;

a transmitter configured to transmit the signal; and

the apparatus according to claim 15.

17. The system as recited in claim 16, wherein the sensor configured to measure the direction of the vector parameter comprises at least one of:

a sensor configured to measure a gravitational field,

a sensor configured to measure a magnetic field, or

a sensor configured to measure an angular orientation.