Multi-touch input discrimination

• US 8,384,684 B2
• Filed: 12/10/2010
• Issued: 02/26/2013
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Westerman, Wayne Carl
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Marinelli, Patrick F
• Application Number:
  US12/965,327
• Publication Number:
  US 20110080365A1
• Time in Patent Office: 809 Days
• Field of Search: 345156-173, 178 1801- 2004, 382/82, 382/312, 382/191, 382/181, 382/203, 382/210
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06V 40/107 Static hand or arm

Abstract

Techniques for identifying and discriminating between different input patterns to a multi-touch touch-screen device are described. By way of example, large objects hovering a short distance from the touch-surface (e.g., a cheek, thigh or chest) may be identified and distinguished from physical contacts to the surface. In addition, rough contacts due to, for example, ears and earlobes, may be similarly identified and distinguished from contacts due to fingers, thumbs, palms and finger clasps.

Claims

1. A method to discriminate input sources to a touch-surface device, comprising:

obtaining a proximity image including at least one patch;

determining a major axis radius value for the at least one patch;

identifying the at least one patch as being associated with a large object when the determined major axis radius value of the at least one patch is above a first specified threshold; and

using the identified patch to control an operation of the touch-surface device.

2. The method of claim 1, wherein obtaining a proximity image includes segmenting the proximity image to identify the at least one patch.

3. The method of claim 1 wherein the large object comprises a leg.

4. The method of claim 1 wherein the large object comprises a cheek.

5. The method of claim 1, further comprising:

determining a major radius value for a second patch;

identifying a second patch as being associated with a palm if the determined major axis radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

using the identified second patch to control an operation of the touch-surface device.

6. The method of claim 5, further comprising:

determining a major radius value for a third patch;

identifying a third patch as being associated with a finger if the determined major axis radius value of the third patch is less than the second specified threshold; and

using the identified third patch to control an operation of the touch-surface device.

7. The method of claim 6, wherein the patch associated with the finger comprises a patch associated with a thumb.

8. The method of claim 1, wherein the act of obtaining comprises:

obtaining a first proximity image, the first proximity image comprising a plurality of pixels for the at least one patch, each pixel having a value; and

subtracting sensor element baseline values from the plurality of pixels values in the first proximity image.

9. The method of claim 1, wherein the act of obtaining comprises:

obtaining a first proximity image; and

filtering the first proximity image to generate a filtered proximity image.

10. The method of claim 9, wherein the act of filtering comprises spatially filtering the first proximity image.

11. The method of claim 10, wherein the act of spatially filtering comprises inserting a border around the first proximity image prior to spatially filtering the first proximity image.

12. The method of claim 9, wherein the act of filtering comprises temporally filtering the first proximity image with a second proximity image.

13. A non-transitory program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform the method of any of claims 8-12.

14. A portable electronic device, comprising:

a touch-surface device;

means for receiving a proximity image from the touch-surface device; and

processing means for performing acts in accordance with any one of claims 1, 5 and 6.

15. A non-transitory program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform the method of claim 1.

16. The non-transitory program storage device of claim 15 wherein the instructions stored thereon further cause the programmable control device to perform the steps of:

identifying a second patch as being associated with a palm if the determined major axis radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

using the identified second patch to control an operation of the touch-surface device.

17. An apparatus for discriminating input sources to a touch surface device comprising:

means for obtaining a proximity image including at least one patch;

means for determining a major axis radius value for the at least one patch;

means for identifying the at least one patch as being associated with a large object when the determined major axis radius value of the at least one patch is above a first specified threshold; and

means for using the identified patch to control an operation of the touch-surface device.

18. The apparatus of claim 17, further comprising:

means for determining a major axis radius value for a second patch;

means for identifying the second patch as being associated with a palm if the determined major axis radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

means for using the identified second patch to control an operation of the touch-surface device.

19. A method to discriminate input sources to a touch-surface device, comprising:

obtaining a proximity image including at least one patch;

determining one of a major axis radius value and a geometric mean radius value for the at least one patch;

identifying the at least one patch as being associated with a large object when the determined major axis radius value or geometric mean radius value of the at least one patch is above a first specified threshold;

determining one of a major axis radius value and a geometric mean radius value for a second patch;

identifying the second patch as being associated with a palm if the determined major axis radius value or geometric mean radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

using the identified second patch to control an operation of the touch-surface device.

20. The method of claim 19, further comprising:

determining one of a major axis radius value and a geometric mean radius value for a third patch;

identifying the third patch as being associated with a finger if the determined one of a major axis radius value and a geometric mean radius value of the third patch is less than the second specified threshold; and

using the identified third patch to control an operation of the touch-surface device.

21. The method of claim 20, wherein the patch associated with the finger comprises a patch associated with a thumb.

22. An apparatus for discriminating input sources to a touch surface device comprising:

means for obtaining a proximity image including at least one patch;

means for determining one of a major axis radius value and a geometric mean radius value for the at least one patch;

means for identifying the at least one patch as being associated with a large object when the determined major axis radius value or geometric mean radius value of the at least one patch is above a first specified threshold;

means for determining one of a major axis radius value and a geometric mean radius value for a second patch;

means for identifying the second patch as being associated with a palm when the determined major axis radius value or geometric mean radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

means for using the identified second patch to control an operation of the touch-surface device.

23. The apparatus of claim 22, further comprising:

means for determining one of a major axis radius value and a geometric mean radius value for a third patch;

means for identifying the third patch as being associated with a finger if the determined one of a major axis radius value and a geometric mean radius value of the third patch is less than the second specified threshold; and

means for using the identified third patch to control an operation of the touch-surface device.

24. A method to discriminate input sources to a touch-surface device, comprising:

obtaining a proximity image including at least one patch;

determining a geometric mean radius value for the at least one patch, the geometric mean radius value computed from the square root of the product of a major axis radius value and a minor axis radius value of the at least one patch;

identifying the at least one patch as being associated with a large object when the determined geometric mean radius value of the at least one patch is above a first specified threshold; and

using the identified patch to control an operation of the touch-surface device.

25. The method of claim 24 further comprising:

determining a geometric mean radius value for a second patch;

identifying the second patch as being associated with a palm if the determined geometric mean radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

using the identified second patch to control an operation of the touch-surface device.

26. The method of claim 25, further comprising:

determining a geometric mean radius value for a third patch;

identifying the third patch as being associated with a finger if the determined geometric mean radius value of the third patch is less than the second specified threshold; and

using the identified third patch to control an operation of the touch-surface device.

27. The method of claim 24, wherein the act of obtaining comprises:

obtaining a first proximity image, the first proximity image comprising a plurality of pixels for the at least one patch, each pixel having a value; and

subtracting sensor element baseline values from the plurality of pixels values in the first proximity image.

28. The method of claim 24, wherein the act of obtaining comprises:

obtaining a first proximity image; and

filtering the first proximity image to generate a filtered proximity image.

29. A portable electronic device, comprising:

a touch-surface device;

means for receiving a proximity image from the touch-surface device; and

processing means for performing acts in accordance with any of claim 24, 25 or 26.

30. A non-transitory program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform the method of claim 24.

31. The non-transitory program storage device of claim 30 wherein the instructions stored thereon further cause the programmable control device to perform the steps of:

identifying a second patch as being associated with a palm if the determined geometric mean radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

using the identified second patch to control an operation of the touch-surface device.

35. A non-transitory program storage device, readable by a programmable control device, comprising instructions stored thereon for causing the programmable control device to perform the method of any of claims 27-34.

32. An apparatus for discriminating input sources to a touch surface device comprising:

means for obtaining a proximity image including at least one patch;

means for determining a geometric mean radius value for the at least one patch, the geometric mean radius value computed from the square root of the product of a major axis radius value and a minor axis radius value of the at least one patch;

means for identifying the at least one patch as being associated with a large object when the determined geometric mean radius value of the at least one patch is above a first specified threshold; and

means for using the identified patch to control an operation of the touch-surface device.

33. The apparatus of claim 32, further comprising:

means for determining a geometric mean radius value for a second patch;

means for identifying the second patch as being associated with a palm if the determined geometric mean radius value of the second patch is less than the first specified threshold and greater than a second specified threshold; and

means for using the identified second patch to control an operation of the touch-surface device.

34. A method to discriminate input sources to a touch-surface device, comprising:

obtaining a proximity image including at least one patch;

determining a size parameter value of a size parameter, the size parameter value indicative of a size of each of the plurality of patches, the size parameter value being one of a minor axis radius value or a major axis radius value;

determining a signal density value for each of the plurality of patches;

identifying the at least one patch as being associated with a large object when the determined size parameter value of the at least one patch is above a first specified threshold, the first specified threshold being a linear or non-linear relationship between signal density values and size parameter values; and

using the identified patch to control an operation of the touch-surface device.

36. An apparatus to discriminate input sources to a touch-surface device, comprising:

means for obtaining a proximity image including at least one patch;

means for determining a size parameter value of a size parameter, the size parameter value indicative of a size of each of the plurality of patches, the size parameter value being one of a minor axis radius value or a major axis radius value;

means for determining a signal density value for each of the plurality of patches;

means for identifying the at least one patch as being associated with a large object when the determined size parameter value of the at least one patch is above a first specified threshold, the first specified threshold being a linear or non-linear relationship between signal density values and size parameter values; and

means for using the identified patch to control an operation of the touch-surface device.