Method for real time interactive visualization of muscle forces and joint torques in the human body

• US 7,931,604 B2
• Filed: 10/15/2008
• Issued: 04/26/2011
• Est. Priority Date: 03/07/2007
• Status: Active Grant

• Current Assignee: Motek BV
• Original Assignee: Motek BV
• Inventors: Even Zohar, Oshri, van den Bogert, Antonie J
• Primary Examiner(s): Hindenburg; Max
• Assistant Examiner(s): DOUGHERTY, SEAN PATRICK
• Application Number:
  US12/251,688
• Publication Number:
  US 20090082701A1
• Time in Patent Office: 923 Days
• Field of Search: 345/156, 345/473, 382/107, 382/111, 600/595, 600/587, 703/2
• US Class Current: 600/595
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1114 Tracking parts of the body
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/224 Measuring muscular strength
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/6804 Garments; Clothes
• CPC Class Codes: G09B 23/28 for medicine

Abstract

A method and system are provided for the visual display of anatomical forces, that system having: a motion capture system; a computer, receiving data from said motion capture system; and a computational pipeline disposed on said computer; that computational pipeline being configured to calculate muscle forces and joint torques in real time and visually display those forces and torques.

Claims

1. A method for computing, measuring, recording and viewing in real time muscle forces and joint moments of a body in motion, employing a system for visual display and output of anatomical forces, said system comprising:

a motion capture system for collecting and recording real time position data;

a computer receiving data from said motion capture system and deriving rotational data therefrom;

a first look up table comprising biomechanical body skeleton definition and marker set templates, a second look up table comprising body mass properties, and a third look up table comprising muscle paths;

a computational pipeline disposed on said computer; and

a computer display unit for displaying color animation,

said method comprising;

placing the body in motion within range of the motion capture system;

collecting and recording in real time three dimensional coordinates of selected marker points on the body in motion;

calculating in real time a skeleton pose of the body in motion from the three dimensional coordinates and from said first look up table;

calculating in real time joint moments of the body using the skeleton pose of the body in motion, a first derivative velocity of the skeleton pose, a second derivative acceleration of the skeleton pose, force vectors representing external forces affecting the body in motion, and body mass properties from said second look up table;

calculating in real time muscle lengths and muscle moment arms using the skeleton pose and said third look up table;

calculating in real time muscle forces using the joint moments, muscle lengths and muscle moment arms, by using quadratic programming and a neural network optimization algorithm for said quadratic programming; and

generating and displaying in real time from the calculated muscle forces while the body in motion remains in motion, a color animation of a muscle model whereby a relative degree of muscle force of the body in motion is displayed by a relative coloring of the respective muscles of the color animation.

2. The method of claim 1, wherein said color animation of a muscle model further comprises joint moments presented by scale and color of three dimensional vector animations.

3. The method of claim 1, further comprising:

placing at least one motion capture marker on said body defining said three dimensional coordinates;

collecting and recording real time positional data from said at least one marker; and

deriving rotational data from said at least one of the motion capture markers.

4. The method of claim 1, wherein said body in motion is a human body, and said color animation is being displayed to said body in motion in real time as visual feedback.

5. The method of claim 1, wherein said motion capture system comprises sensors for said collecting and recording of real time position data, the sensors selected from the group of sensors consisting of optical, magnetic, inertial, and video based sensors.

6. The method of claim 1, wherein said system for visual display and output of anatomical forces comprises an instrumented platform supporting said body in motion.

7. The method of claim 2 wherein said muscle forces and said joint moments are displayed on a representation of a human body.

8. The method of claim 4, further comprising:

selecting a biomechanical body skeleton definition and marker set template approximating a build of the human body.

9. The method of claim 1, wherein said computation pipeline comprises use of a Jacobian matrix to facilitate said computing in real time.

10. A method for viewing in real time muscle forces and joint moments of a body in motion employing a system for visual display and output of anatomical forces, said system comprising:

a motion capture system for collecting and recording real time position data;

a computer receiving data from said motion capture system and deriving rotational data therefrom;

a first look up table comprising biomechanical body skeleton definition and marker set templates, a second look up table comprising body mass properties, and a third look up table comprising muscle paths;

a computational pipeline disposed on said computer; and

a computer display unit for displaying color animation;

said method comprising;

placing a body in motion within range of said motion capture system;

calculating in real time a skeleton pose of the body in motion from three dimensional coordinates of selected marker points on the body in motion and from said first look up table;

calculating in real time joint moments of the body in motion using the skeleton pose of the body, a first derivative velocity of the skeleton pose, a second derivative acceleration of the skeleton pose, force vectors representing external forces affecting the body in motion, and body mass properties from said second look up table;

calculating in real time muscle lengths and muscle moment arms using the skeleton pose and said third look up table;

calculating in real time muscle forces of the body in motion using the joint moment, muscle lengths and muscle moment arms, and optimization algorithms;

generating and displaying in real time from the calculated muscle forces a color animation of a muscle model whereby a relative degree of muscle force of the body in motion is presented by relative coloring of the respective muscles in the color animation; and

having an operator interact with the system during system runtime.