TOUCH TRACKING ON A TOUCH SENSITIVE INTERFACE

• US 20100309139A1
• Filed: 06/03/2009
• Published: 12/09/2010
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Ng, Hon Siong
• Granted Patent: US 9,134,848 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04186 Touch location disambiguation

Abstract

A method tracks a plurality of touch points across successive frames of a touch sensitive input device to determine a trajectory. Each touch point on a frame of a touch sensitive input device is correlated with another distinct touch point on a subsequent frame of the same touch sensitive input device. The correlation is based on examining in the subsequent frame an area surrounding each touch point on the previous frame. Touch points identified within this search area are prioritized based on a projected trajectory through the prior touch point based on historical data.

Claims

1. A method for tracking a plurality of touch points across frames of a touch sensitive input device, the method comprising:

correlating each touch point on a first frame of the touch sensitive input device with a distinct touch point on a subsequent frame of the touch sensitive input device, wherein correlating is based on isolating the at least one distinct touch point by a search distance associated with each touch point on the first frame and a trajectory associated with each touch point on the first frame.

2. The method of claim 1 wherein the search distance surrounding each touch point on the first frame for capturing the distinct touch point on the subsequent frame is independently determined.

3. The method of claim 2 wherein magnitude of the search distance for points on the subsequent frame is based on a differential positional change of each touch point between the first frame and a prior frame.

4. The method of claim 2 wherein touch points identified on the subsequent frame outside of the search distance of any touch point on the first frame are designated as new touch points.

5. The method of claim 1 wherein the trajectory for each touch point on the first frame is based on projecting an association between the touch point on the first frame and a touch point on a prior frame.

6. The method of claim 1 wherein responsive to more than one touch point on the subsequent frame being within the search distance associated with each touch point on the first frame, identifying which of the more than one touch point is more closely aligned with the trajectory associated with each touch point on the first frame.

7. The method of claim 6 further comprising selecting the identified more than one touch point as the distinct touch point on the subsequent frame.

8. The method of claim 1 wherein a historical record of each touch point for each frame is stored.

9. A computer-readable storage medium tangibly embodying a program of instructions executable by a machine wherein said program of instructions comprises a plurality of program codes for tracking a plurality of touch points across frames of a touch sensitive input device, said program of instructions comprising:

program code for correlating each touch point on a first frame of the touch sensitive input device with a distinct touch point on a subsequent frame of the touch sensitive input device, wherein correlating is based on isolating the at least one distinct touch point by a search distance associated with each touch point on the first frame and a trajectory associated with each touch point on the first frame.

10. The computer-readable storage medium of claim 9 wherein the search distance surrounding each touch point on the first frame for capturing the distinct touch point on the subsequent frame in the program code for correlating is independently determined.

11. The computer-readable storage medium of claim 10 wherein magnitude of the search distance for points on the subsequent frame in the program code for correlating is based on a differential positional change of each touch point between the first frame and a prior frame.

12. The computer-readable storage medium of claim 10 wherein touch points identified on the subsequent frame outside of the search distance of any touch point on the first frame in the program code for correlating are designated as new touch points.

13. The computer-readable storage medium of claim 9 wherein the trajectory for each touch point on the first frame in the program code for correlating is based on projecting an association between the touch point on the first frame and a touch point on a prior frame.

14. The computer-readable storage medium of claim 9 wherein responsive to more than one touch point on the subsequent frame being within the search distance associated with each touch point on the first frame, further comprising program code for identifying which of the more than one touch point is more closely aligned with the trajectory associated with each touch point on the first frame.

15. A computer system for tracking a plurality of touch points across frames of a touch sensitive input device, the computer system comprising:

a machine capable of executing instructions embodied as software; and

a plurality of software portions, wherein

one of said software portions is operable to correlate each touch point on a first frame of the touch sensitive input device with a distinct touch point on a subsequent frame of the touch sensitive input device, wherein correlating is based on isolating the at least one distinct touch point by a search distance associated with each touch point on the first frame and a trajectory associated with each touch point on the first frame.

16. The computer system of claim 15 wherein the search distance surrounding each touch point on the first frame for capturing the distinct touch point on the subsequent frame is independently determined.

17. The computer system of claim 16 wherein magnitude of the search distance for points on the subsequent frame is based on a differential positional change of each touch point between the first frame and a prior frame.

18. The computer system of claim 16 wherein touch points identified on the subsequent frame outside of the search distance of any touch point on the first frame are designated as new touch points.

19. The computer system of claim 15 wherein the trajectory for each touch point on the first frame is based on projecting an association between the touch point on the first frame and a touch point on a prior frame.

20. The computer system of claim 15 wherein responsive to more than one touch point on the subsequent frame being within the search distance associated with each touch point on the first frame, identifying which of the more than one touch point is more closely aligned with the trajectory associated with each touch point on the first frame.