Method and apparatus for tracking, storing, and synthesizing an animated version of object motion

• US 6,072,504 A
• Filed: 06/20/1997
• Issued: 06/06/2000
• Est. Priority Date: 06/20/1997
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Segen, Jakub
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): NGUYEN, THU V
• Application Number:
  US08/880,092
• Time in Patent Office: 1,082 Days
• Field of Search: 345/473-475, 348/46-48, 434/247-252, 382/154, 382/107
• US Class Current: 345/474
• CPC Class Codes: G06T 13/20 3D [Three Dimensional] animation
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments

Abstract

The specification relates to a method and apparatus for tracking object position during active segments of motion monitored from a plurality of video cameras, repetitively sampling object position, representing various object trajectories during active segments as equations, and synthesizing an animated version of the motion of the object from the representative equations. The present description is described in the context of synthesis of an animated version of a tennis game, although a representation of object motion of any sort is equally applicable, if the object motion is capable of being reduced to the form of an equation or series of equations. In a further enhancement, player position, player extremities, and player controlled objects (such as a racquet) are also tracked and sampled and utilized to provide an animation more faithfully reproducing player position, player motion and other game parameters.

Claims

1. A method for synthesizing an animation of object motion utilizing a plurality of video cameras and at least one digital processor, said object motion capable of description with at least one object trajectory, said method comprising the steps of:

generating a plurality of sequential three-dimensional positions for an object;

concatenating said plurality of sequential three-dimensional positions into at least one segment of unimpeded motion, each of said at least one segment of unimpeded motion commencing and terminating with a point of interaction;

generating a trajectory equation for each of at least one segment of unimpeded motion;

determining a point of intersection for two sequential trajectory equations representing two respective segments of unimpeded motion; and

utilizing said point of intersecting as said point of interaction when generation of said plurality of sequential three-dimensional positions for said object is interrupted contemporaneously with the occurrence of said point of interaction; and

synthesizing said animation utilizing each of said trajectory equations and each of said points of interaction as animation variables.

2. The method in accordance with claim 1 wherein a plurality of objects in motion are tracked and reduced to a respective plurality of trajectory equations, said respective plurality of trajectory equations utilized as animation variables.

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

storing said at least one trajectory equation within a storage medium enabling subsequent animation utilizing each of said at least one trajectory equation.

4. The method in accordance with claim 3 wherein said storage medium is a CD-ROM.

5. A method for synthesizing an animated version of a live action game utilizing a plurality of video cameras and at least one digital processor, said live action game including an object, said object having at least one object trajectory as an integral component of said live action game, said method comprising the steps of:

tracking a sequence of two-dimensional positions of said object with at least two of said plurality of video cameras during periods of active play;

triangulating a plurality of sequential three-dimensional positions over time for said object utilizing said two-dimensional positions of said object resulting from said at least two of said plurality of video cameras;

concatenating said plurality of sequential three-dimensional positions into at least one segment of unimpeded motion, each of at least one segment of unimpeded motion commencing and terminating with a point of interaction;

representing each of at least one segment of unimpeded motion with a trajectory equation;

determining, from a plurality of points of interaction, which of said plurality of points of interaction are attributable to player interaction; and

synthesizing said animated version of said live action game with an animation program resident at one of said at least one digital processor, said animation program utilizing each of said points of interaction, points of interaction attributable to player interaction, and trajectory equations as animation variables.

6. The method in accordance with claim 5 wherein at least one of said plurality of cameras are mounted in a fixed configuration.

7. The method in accordance with claim 5 wherein at least one of said plurality of cameras are mounted in a movable configuration.

8. The method in accordance with claim 5 wherein a plurality of objects in motion are tracked and reduced to a respective plurality of trajectory equations, said respective plurality of trajectory equations utilized as animation variables.

9. The method in accordance with claim 5 wherein at least one player'"'"'s position is tracked in time in addition to said object.

10. The method in accordance with claim 9 wherein at least one player'"'"'s extremity position is tracked in time in addition to said at least one player position.

11. The method in accordance with claim 5 wherein said animated version of said live game action is operable to be viewed from a virtual camera at a user defined pseudo-location.

12. A method for synthesizing an animated version of a live action tennis match utilizing a plurality of video cameras and a microprocessor, said method comprising the steps of:

tracking a sequence of two-dimensional positions for a tennis ball, with at least two of said plurality of video cameras, during periods of active play;

triangulating a plurality of sequential three-dimensional positions over time for said tennis ball utilizing said two-dimensional positions for said tennis ball attributable to said at least two of said plurality of video cameras;

concatenating said plurality of sequential three-dimensional positions into at least one segment of unimpeded motion, each of at least one segment of unimpeded motion commencing and terminating with a point of interaction;

representing each of at least one segment of unimpeded motion with a trajectory equation;

determining, from a plurality of points of interaction, which of said plurality of points of interaction are attributable to player interaction; and

synthesizing said animated version of said live action tennis match with an animation program running on said microprocessor, said animation program utilizing each of said points of interaction, points of interaction attributable to player interaction, and trajectory equations as animation variables.

13. The method in accordance with claim 12 further comprising the step of storing each of said points of interaction, points of interaction attributable to player interaction, and trajectory equations within a storage medium enabling subsequent animation.

14. The method in accordance with claim 13 wherein said storage medium is a CD-ROM.

15. The method in accordance with claim 12 wherein said plurality of cameras are mounted in a fixed configuration.

16. The method in accordance with claim 12 wherein said plurality of cameras are mounted in a movable configuration.

17. The method in accordance with claim 12 wherein at least one player'"'"'s position is tracked in time in addition to said tennis ball.

18. The method in accordance with claim 17 wherein at least one player'"'"'s extremity position is tracked in time in addition to said at least one player position.

19. The method in accordance with claim 18 wherein at least one player'"'"'s racquet position is tracked in time in addition to said at least one player position.

20. The method in accordance with claim 12 wherein said animated version of said live action tennis match is operable to be viewed from a virtual camera at a user defined pseudo-location.

21. A system for synthesis of an animated version of a live action tennis match comprising:

a plurality of video cameras, at least two of said plurality of video cameras tracking a sequence of two-dimensional positions for a tennis ball during periods of active play;

means for transmitting said sequence of two-dimensional positions from said plurality of video cameras to a digital processor;

means for triangulating a plurality of sequential three-dimensional positions for said tennis ball from said sequence of two-dimensional positions of said tennis ball;

means for concatenating said plurality of sequential three-dimensional positions into at least one segment of unimpeded motion each of said at least one segment of unimpeded motion commencing and terminating with a point of interaction;

means for assigning a representative equation to each of said at least one segment of unimpeded motion;

means for determining a point of intersection for two sequential trajectory equations representing two respective segments of unimpeded motion;

means for utilizing said point of intersection as said point of interaction when generation of said plurality of sequential three-dimensional positions for said object is interrupted contemporaneously with the occurrence of said point of interaction; and

means for animating a synthetic version of said live action tennis match utilizing each of said representative equations assigned to each of said at least one segment of unimpeded motion and each of said points of interaction.

22. The system as recited in claim 21 further comprising means for tracking at least one player'"'"'s position to provide for accurate player position during a subsequent animation of said synthetic version of said live action tennis match.

23. The system as recited in claim 22 further comprising means for tracking at least one player'"'"'s extremity to provide for accurate extremity position during a subsequent animation of said synthetic version of said live action tennis match.

24. The system as recited in claim 22 further comprising means for tracking at least one player'"'"'s racquet position to provide for accurate racquet position during a subsequent animation of said synthetic version of said live action tennis match.