Joint component framework for modeling complex joint behavior

• US 20060061574A1
• Filed: 04/25/2003
• Published: 03/23/2006
• Est. Priority Date: 04/25/2003
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Ng-Thow-Hing, Victor, Shao, Wei
• Granted Patent: US 7,333,111 B2
• Time in Patent Office: Days
• US Class Current: 345/473
• CPC Class Codes: G06T 13/40 of characters, e.g. humans, animals or virtual beings
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics
• CPC Class Codes: G06T 2210/41 Medical
• CPC Class Codes: G06T 2213/04 Animation description language

Abstract

A general joint component framework that is capable of exhibiting complex behaviors of joints in articulated figures is provided. A network of joint components is used to model the kinematics of a joint. A joint builder can specify parameters for each of the joint components and join the joint components to form a joint set function that captures the biomechanical dependencies between the components. The joint function has fewer inputs than the total number of possible articulations yielding both simple control and biomechanically accurate joint movement.

Claims

1. A method for building a joint set function for a target joint, the method comprising the steps of:

selecting a first joint component comprising a first function including a parameter;

setting the parameter to define behavior of the first joint component;

selecting a second joint component comprising a second function; and

coupling the first joint component and the second joint component into a network to produce the joint set function,

wherein the front joint set function specifies a transformation matrix and wherein, if a segment of the target joint has one or more parent segments, the transformation matrix is unequal to a product of transformation matrices of joints of the one or more parent segments.

3. The method of claim 1 further comprising the step of:

testing the joint set function to determine whether desired articulated motion is produced.

4. The method of claim 3 wherein the testing step further comprises the step of:

producing a visual display of joint motion.

5. The method of claim 3 wherein the testing step further comprises the step of:

manipulating an input to the joint set function over a range of values.

6. The method of claim 3 further comprising the step of:

modifying the parameter responsive to the testing step when articulated motion is undesirable.

7. The method of claim 3 further comprising the step of:

modifying the network of joint component couplings responsive to the testing step when articulated motion is undesirable.

8. The method of claim 1 further comprising the step of:

storing the joint set function in a data file.

9. The method of claim 8 wherein the data file is in XML format.

2. (canceled)

10. A computer-readable medium in which a joint component model is encoded, the joint component model representing joint expressions over a plurality of bone segments, the model comprising:

a first joint component including an input, an output, and a parameter, the first joint component configured to map the input to the output, wherein the mapping is controlled by the parameter;

a second joint component including an input and an output, the second joint component configured to map the input to the output; and

a joint set function including a network of the first joint component and the second joint component, the joint set function having a joint set function input and a joint set function output, the joint set input configured to provide a control for a user, the joint set output configured to provide a transformation matrix for manipulating a bone segment of the plurality of bone segments,

wherein, if the bone segment has one or more parent segments, the transformation matrix is unequal to a product of transformation matrices of joints of the one or more parent segments.

11. The computer-readable medium of claim 10 wherein the joint set function includes one element of a set containing a matrix multiplication component, a one-to-many mapping component, a compensation component, a rotation component, a dependency component, a joint cone component, and a scapula constraint component.

12. The computer-readable medium of claim 10 wherein either the first joint component or the second joint component can be reused to form an additional network of joint components.

13. The computer-readable medium of claim 11 wherein the rotation component is configured to model a changing joint center.

14. The computer-readable medium of claim 11 wherein the scapula component includes two ellipsoids configured to constrain the scapula bone using pairs of reference points.

15. The computer-readable medium of claim 11 wherein the joint cone component is configured to generate a boundary curve and to project an invalid orientation back to the boundary curve.

16. The computer-readable medium of claim 11 wherein the compensation component is configured to cancel out orientation transformation caused by an ancestor segment of the bone segment while maintaining joint connectivity.

17. An apparatus for building a joint set function for a target joint, the apparatus comprising:

means for selecting a first joint component comprising a first function including a parameter;

means for setting the parameter to define behavior of the first joint component;

means for selecting a second joint component comprising a second function; and

means for coupling the first joint component and the second joint component into a network to produce the joint set function,

wherein the joint set function specifies a transformation matrix and wherein, if a segment of the target joint has one or more parent segments, the transformation matrix is unequal to a product of transformation matrices of joints of the one or more parent segments.

19. The apparatus of claim 17 further comprising:

means for testing the joint set function to determine whether desired articulated motion is produced.

20. The apparatus of claim 19 wherein the means for testing further comprises:

means for producing a visual display of joint motion.

21. The apparatus of claim 19 wherein the means for testing further comprises:

means for manipulating joint set function inputs over a predetermined range of values.

22. The apparatus of claim 19 further comprising:

means for modifying the parameter responsive to the means for testing when articulated motion is undesirable.

23. The apparatus of claim 19 further comprising:

means for modifying the network of joint component couplings responsive to the means for testing when articulated motion is undesirable.

24. The apparatus of claim 17 further comprising:

means for storing the joint set function in a data file.

25. The apparatus of claim 24 wherein the data file is in XML format.

18. (canceled)

26. A computer readable medium including program instructions for building a joint set function for a target joint, the computer readable medium comprising:

program instructions for selecting a first joint component comprising a first function including a parameter;

program instructions for setting the parameter to define behavior of the first joint component;

program instructions for selecting a second joint component comprising a second function; and

program instructions for coupling the first joint component and the second joint component into a network to produce the joint set function,

wherein the joint set function specifies a transformation matrix and wherein, if a segment of the target joint has one or more parent segments, the transformation matrix is unequal to a product of transformation matrices of joints of the one or more parent segments.

28. The computer readable medium of claim 26 further comprising:

program instructions for testing the joint set function to determine whether desired articulated motion is produced.

29. The computer readable medium of claim 28 wherein the program instructions for testing further comprises:

means for producing a visual display of joint motion.

30. The computer readable medium of claim 28 wherein the program instructions for testing further comprises:

program instructions for manipulating a joint set function input over a range of values.

31. The computer readable medium of claim 28 further comprising:

program instructions for modifying the parameter responsive to the program instructions for testing when articulated motion is undesirable.

32. The computer readable medium of claim 28 further comprising:

program instructions for modifying the network of joint component couplings responsive to the program instructions for testing when articulated motion is undesirable.

33. The computer readable medium of claim 26 further comprising:

program instructions for storing the joint set function in a data file.

34. The computer readable medium of claim 33 wherein the data file is in XML format.

27. (canceled)