Tracking bimanual movements

• US 20050238201A1
• Filed: 04/15/2005
• Published: 10/27/2005
• Est. Priority Date: 04/15/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: GestureTek Incorporated (Winning Brands Corp.)
• Inventors: Shamaie, Atid
• Granted Patent: US 7,379,563 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16
• CPC Class Codes: G06V 40/28 Recognition of hand or arm movements, e.g. recognition of deaf sign language static hand signs G06V40/113

Abstract

Hands may be tracked before, during, and after occlusion, and a gesture may be recognized. Movement of two occluded hands may be tracked as a unit during an occlusion period. A type of synchronization characterizing the two occluded hands during the occlusion period may be determined based on the tracked movement of the occluded hands. Based on the determined type of synchronization, it may be determined whether directions of travel for each of the two occluded hands change during the occlusion period. Implementations may determine that a first hand and a second hand are occluded during an occlusion period, the first hand having come from a first direction and the second hand having come from a second direction. The first hand may be distinguished from the second hand after the occlusion period based on a determined type of synchronization characterizing the two hands, and a behavior of the two hands.

Claims

1. A method comprising:

tracking movement of two occluded hands during an occlusion period, the two occluded hands being tracked as a unit;

determining a type of synchronization characterizing the two occluded hands during the occlusion period based on the tracked movement of the two occluded hands; and

determining, based on the determined type of synchronization, whether directions of travel for each of the two occluded hands change during the occlusion period.

2. The method of claim 1 wherein determining whether directions change is further based on the tracked movement of the two occluded hands.

3. The method of claim 1 wherein determining whether directions change comprises determining whether the two hands pass each other during the occlusion period.

4. The method of claim 1 wherein determining whether directions change comprises determining whether the two hands perform one or more of pausing or colliding with each other during the occlusion period.

5. The method of claim 1 wherein determining whether directions change comprises determining whether each of the two hands return, after the occlusion period, to directions from which they came.

6. The method of claim 5 wherein the directions from which the two hands came include one or more of a vertical direction, a horizontal direction, and a diagonal direction.

7. The method of claim 1 wherein determining whether direction change comprises determining whether each of the two hands go, after the occlusion period, to directions opposite from which they came.

8. The method of claim 1 wherein:

determining a type of synchronization comprises determining whether the two hands are positively or negatively synchronized, and

determining whether directions change is further based on whether the two hands are negatively synchronized.

9. The method of claim 1 wherein determining a type of synchronization comprises determining a measure of the occluded hands'"'"' velocities.

10. The method of claim 9 wherein the measure comprises a standard deviation of a difference of velocities of parallel sides of a rectangle formed to surround the occluded hands.

11. The method of claim 1 wherein:

tracking movement of the two occluded hands comprises tracking movement of a rectangle formed to surround the occluded hands, and

determining whether directions change comprises determining a measure of the occluded hands'"'"' velocities based on velocities of one or more sides of the rectangle.

12. The method of claim 11 wherein determining whether directions change is based on whether the measure goes below a threshold.

13. The method of claim 12 wherein the measure is a function of a square root of a sum of squares of velocities of parallel sides of the rectangle.

14. The method of claim 11 wherein determining whether directions change is based on one or more probability distributions of the measure.

15. The method of claim 14 wherein the measure is a function of a difference of velocities of parallel sides of the rectangle.

16. The method of claim 14 wherein the one or more probability distributions comprises a first set of distributions associated with a first velocity pattern and a second set of distributions associated with a second velocity pattern.

17. The method of claim 16 wherein the first velocity pattern is indicative of the two hands passing each other during the occlusion period, and the second velocity pattern is indicative of the two hands not passing each other during the occlusion period.

18. The method of claim 17 wherein determining whether directions change further comprises:

determining a first probability, based on the first set of distributions, that the first velocity pattern produced the measure of the occluded hands'"'"' velocities;

determining a second probability, based on the second set of distributions, that the second velocity pattern produced the measure of the occluded hands'"'"' velocities;

comparing the first probability with the second probability; and

determining, based on a result obtained during the comparing, whether the two occluded hands pass each other during the occlusion period.

19. A device comprising a computer readable medium having instructions stored thereon for performing at least the following:

tracking movement of two occluded hands during an occlusion period, the two occluded hands being tracked as a unit;

determining a type of synchronization characterizing the two occluded hands during the occlusion period based on the tracked movement of the two occluded hands; and

determining, based on the determined type of synchronization, whether directions of travel for each of the two occluded hands change during the occlusion period.

20. A method comprising:

determining that a first hand and a second hand are occluded, the first hand having come from a first direction and the second hand having come from a second direction;

tracking movement of the occluded hands, the two occluded hands being tracked as a unit;

determining a type of synchronization characterizing the occluded hands based on the tracked movement of the occluded hands;

determining that the first hand and the second hand are no longer occluded; and

distinguishing, after determining that the first hand and the second hand are no longer occluded, the first hand from the second hand based on the determined type of synchronization.