Systems and methods for providing normalized parameters of motions of objects in three-dimensional space

• US 9,747,696 B2
• Filed: 05/19/2014
• Issued: 08/29/2017
• Est. Priority Date: 05/17/2013
• Status: Active Grant

• Current Assignee: Lmi Liquidating Co., LLC
• Original Assignee: Leap Motion Incorporated (Ultraleap Limited)
• Inventors: Holz, David
• Primary Examiner(s): Vo, Tung
• Assistant Examiner(s): Jiang, Zaihan
• Application Number:
  US14/281,804
• Publication Number:
  US 20140340524A1
• Time in Patent Office: 1,198 Days
• Field of Search: 348169, 382103
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10021 Stereoscopic video; Stereoscopic image sequence
• CPC Class Codes: G06T 2207/30196 Human being; Person
• CPC Class Codes: G06T 7/251 involving models
• CPC Class Codes: G06V 10/25 Determination of region of interest [ROI] or a volume of interest [VOI]
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16

Abstract

Systems and methods are disclosed for detecting user gestures using detection zones to save computational time and cost and/or to provide normalized position-based parameters, such as position coordinates or movement vectors. The detection zones may be established explicitly by a user or a computer application, or may instead be determined from the user'"'"'s pattern of gestural activity. The detection zones may have three-dimensional (3D) boundaries or may be two-dimensional (2D) frames. The size and location of the detection zone may be adjusted based on the distance and direction between the user and the motion-capture system.

Claims

1. A method of tracking a movement of an object in 3D space, the method comprising:

capturing a plurality of temporally sequential images of the object within the 3D space;

automatically defining a detection zone in the 3D space, the detection zone including at least a portion of the object;

computationally analyzing the images to determine movement parameters associated with, and describing movement of, the object portion as the object portion moves in at least three dimensions, including a first dimension, a second dimension and a third dimension freely through the 3D space at least partially within the detection zone;

computationally scaling the movement parameters to generate normalized parameters normalized in the at least three dimensions relative to the detection zone;

tracking occurrences of motions of the object falling outside of the detection zone and for occurrences of motions of the object falling outside of the detection zone, adjusting a value of a discard parameter to reflect the occurrence; and

comparing the discard parameter to a threshold and based upon a result of the comparing, altering the detection zone.

2. The method of claim 1, wherein the detection zone has three-dimensional boundaries.

3. The method of claim 1, wherein the detection zone has two-dimensional boundaries.

4. The method of claim 1, further comprising altering a size of the detection zone to conform to movement of the object.

5. The method of claim 1, further comprising computationally determining a discard parameter value, wherein the discard parameter value relates to a quantity of instances of the object being detected within the 3D space and outside of the detection zone.

6. The method of claim 1, wherein the threshold is a predetermined threshold, the method further comprising enlarging the detection zone when the discard parameter is above the predetermined threshold value.

7. The method of claim 1, wherein the threshold is a predetermined threshold, the method further comprising shrinking the detection zone when the discard parameter is below the predetermined threshold value.

8. The method of claim 1, further comprising altering a position of the detection zone based on a detected position of the object.

9. The method of claim 1, wherein a size of the detection zone is initially determined based on a distance between the object and a motion-capture system.

10. The method of claim 1, wherein the movement parameters are rescaled based on dimensions of the detection zone.

11. The method of claim 1, wherein the movement parameters are rescaled based on a maximum number of pixels in the captured images.

12. The method of claim 1, further comprising computationally analyzing the images to determine movement parameters associated with the object'"'"'s movement outside the detection zone;

wherein the computational analysis of the object outside the detection zone is coarser that the computational analysis of the object within the detection zone.

13. A system for tracking movement of an object in 3D space, the system comprising:

at least one camera oriented toward a field of view;

at least one light source for directing illumination into the field of view, the camera cooperating with the at least one light source to capture a plurality of temporally sequential images of the field of view when illuminated by the at least one light source; and

an image analyzer configured to;

automatically define a detection zone in 3D space, the detection zone including at least a portion of the object;

computationally analyze the images to determine movement parameters associated with, and describing movement of, the object portion as the object portion moves in at least three dimensions, including a first dimension, a second dimension and a third dimension freely through the 3D space at least partially within the detection zone; and

computationally rescale the movement parameters to generate normalized parameters normalized in the at least three dimensions relative to the detection zone;

tracking occurrences of motions of the object falling outside of the detection zone and for occurrences of motions of the object falling outside of the detection zone, adjust a value of a discard parameter to reflect the occurrence; and

compare the discard parameter to a threshold and based upon a result of the comparing, alter the detection zone.

14. The system of claim 13, wherein the image analyzer is further configured to dynamically adjust a size of the detection zone based on the object'"'"'s movements.

15. The system of claim 13, wherein the image analyzer is further configured to computationally determine a discard parameter value, wherein the discard parameter value relates to a quantity of instances of the object being detected within the 3D space and outside of the detection zone.

16. The system of claim 13, wherein the threshold is a predetermined threshold and wherein the image analyzer is further configured to enlarge the detection zone when the discard parameter is above the predetermined threshold value.

17. The system of claim 13, wherein the threshold is a predetermined threshold and wherein the image analyzer is further configured to shrink the detection zone when the discard parameter is below the predetermined threshold value.

18. The system of claim 13, wherein the image analyzer is further configured to adjust a position of the detection zone based on a position of the object.

19. The system of claim 13, wherein the image analyzer is further configured to determine a size of the detection zone based on a distance between the object and the at least one camera.

20. The system of claim 13, wherein the image analyzer is further configured to rescale the movement parameters based on dimensions of the detection zone.

21. The system of claim 13, wherein the image analyzer is further configured to rescale the movement parameters based on a maximum number of pixels in the captured images.

22. The system of claim 13, wherein the image analyzer is further configured computationally analyze the images to determine movement parameters associated with the object'"'"'s movement outside the detection zone;

wherein the computational analysis of the object outside the detection zone is coarser that the computational analysis of the object within the detection zone.