PERIPHERAL PIXEL NOISE REDUCTION

• US 20080158147A1
• Filed: 01/03/2007
• Published: 07/03/2008
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Hotelling, Steve, Westerman, Wayne Carl
• Granted Patent: US 7,643,010 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06V 10/30 Noise filtering
• 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. In one implementation, a unique technique to reduce the noise in segmented image peripheral pixels.

Claims

1. A method to reduce noise in multi-touch touch-surface device operations, comprising:

obtaining a proximity image from a multi-touch touch-surface, the proximity image having a plurality of pixels, each pixel having a value;

segmenting the proximity image to identify one or more patches, each patch comprising a plurality of proximity image pixels;

reducing the value of a patch pixel based on a function of the patch pixel'"'"'s value and the value of a neighbor pixel to the patch pixel; and

using the reduced patch pixel values to parameterize the patch.

2. The method of claim 1, further comprising using the parameterized patch to identify an object contacting the multi-touch touch-surface.

3. The method of claim 2, further comprising, using the identified object to control an operation of a multi-touch touch-surface device.

4. The method of claim 3, wherein the act of controlling an operation comprises performing a user-specified operation.

5. The method of claim 4, wherein the user-specified operation comprises activating the multi-touch touch-surface device.

6. The method of claim 3, wherein the user-specified operation comprises ignoring the identified object contacting the multi-touch touch-surface.

7. The method of claim 3, wherein the multi-touch touch-surface device comprises one of a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.

8. The method of claim 1, further comprising using the parameterized patch to identify an object hovering above, but not contacting, the multi-touch touch-surface.

9. The method of claim 8, further comprising, using the identified object to control an operation of a multi-touch touch-surface device.

10. The method of claim 9, wherein the act of controlling an operation comprises performing a user-specified operation.

11. The method of claim 10, wherein the user-specified operation comprises activating the multi-touch touch-surface device.

12. The method of claim 9, wherein the act of controlling an operation comprises ignoring the identified object.

13. The method of claim 9, wherein the multi-touch touch-surface device comprises one of a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.

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

filtering the proximity image to generate a filtered proximity image the filtered proximity image having a plurality of pixels, each pixel having a value; and

constraining at least one pixel value in the filtered proximity image.

15. The method of claim 14, wherein the act of filtering comprises spatially filtering the proximity image.

16. The method of claim 15, wherein the act of spatially filtering comprises inserting a border around the proximity image prior to spatially filtering the proximity image.

17. The method of claim 1, wherein the act of segmenting comprises constraining one or more pixel values in the proximity image.

18. The method of claim 17, wherein the act of constraining comprises setting the value of each pixel in the proximity image that is below a first threshold to a first value.

19. The method of claim 18, wherein the first value comprises a value corresponding to a background value for the proximity image.

20. The method of claim 19, wherein the background value comprises a single value for all pixels.

21. The method of claim 19, wherein the background value comprises a value that is unique for each pixel.

22. The method of claim 19, wherein the background value is zero.

23. The method of claim 14, wherein the act of reducing comprises reducing the value of a patch pixel by an amount that is proportional to the patch pixel'"'"'s value within a range defined by a first threshold and a second threshold.

24. The method of claim 23, wherein the act of reducing the value of a patch pixel by an amount that is proportional to the patch pixel'"'"'s value within a range defined by the first and second thresholds comprises reducing the value of the patch pixel by an amount that is linearly proportional to the patch pixel'"'"'s value within the range defined by the first and second thresholds.

25. The method of claim 23, wherein the first specified threshold comprises a value that is between approximately 1 standard deviation and 3 standard deviations of a noise value associated with the proximity image.

26. The method of claim 25, wherein the noise value comprises a single value for all pixels in the patch.

27. The method of claim 25, wherein the noise value comprises a value unique for each pixel in the patch.

28. A 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.

29. A portable electronic device, comprising:

a multi-touch input touch-surface component;

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

processing means for performing acts in accordance with claim 1.

30. The device in accordance with claim 29, wherein the portable electronic device comprises a mobile telephone.

31. The device in accordance with claim 29, wherein the portable electronic device is selected from the group consisting of a tablet computer system, a hand-held computer system, a portable music player system, and a portable video player system.

32. A method to reduce noise in touch-surface device operations, comprising:

obtaining a proximity image from a touch-surface, the proximity image having a linear collection of nodes, each node having a value;

segmenting the proximity image to identify one or more patches, each patch comprising a plurality of proximity image nodes;

reducing the value of a patch node based on a function of the patch node'"'"'s value and the value of a neighbor node to the patch node; and

using the reduced patch mpde values to parameterize the patch.

33. The method of claim 32, further comprising using the parameterized patch to identify an object contacting the touch-surface.

34. The method of claim 33, further comprising, using the identified object to control an operation of an electronic device.

35. The method of claim 34, wherein the operation comprises causing the electronic device to change an operational state.

36. The method of claim 34, wherein the operation comprises ignoring the identified object contacting the touch-surface.

37. The method of claim 34, wherein the touch-surface comprises a projection-scan touch-surface.

38. The method of claim 34, wherein the electronic device comprises one of a hand-held computer system, a portable music player system, a personal digital assistant, a portable video player system and a mobile telephone.

39. The method of claim 32, further comprising using the parameterized patch to identify an object hovering above, but not contacting, the touch-surface.

40. The method of claim 39, wherein the touch-surface comprises a projection-scan touch-surface.

41. The method of claim 39, further comprising, using the identified object to control an operation of an electronic device.

42. The method of claim 41, wherein the act of controlling an operation comprises causing the electronic device to change an operational mode.

43. The method of claim 41, wherein the act of controlling an operation comprises ignoring the identified object.

44. The method of claim 41, wherein the electronic device comprises one of a hand-held computer system, a portable music player system, a portable video player system, a personal digital assistant and a mobile telephone.

45. A 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 32.

46. A portable electronic device, comprising:

a input touch-surface component;

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

processing means for performing acts in accordance with claim 32.

47. The device in accordance with claim 46, wherein the portable electronic device comprises a mobile telephone.

48. The device in accordance with claim 46, wherein the portable electronic device is selected from the group consisting of a tablet computer system, a hand-held computer system, a portable music player system, a personal digital assistant and a portable video player system.