Multi-touch input discrimination

• US 8,531,425 B2
• Filed: 07/27/2012
• Issued: 09/10/2013
• Est. Priority Date: 01/03/2007
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Westerman, Wayne Carl
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): MARINELLI, PATRICK
• Application Number:
  US13/560,719
• Publication Number:
  US 20120287074A1
• Time in Patent Office: 410 Days
• Field of Search: 345156-184, 345/104, 178 1801- 2004, 715/863
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 40/107 Static hand or arm
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

Techniques for identifying and discriminating between different types of contacts to a multi-touch touch-screen device are described. Illustrative contact types include fingertips, thumbs, palms and cheeks. By way of example, thumb contacts may be distinguished from fingertip contacts using a patch eccentricity parameter. In addition, by non-linearly deemphasizing pixels in a touch-surface image, a reliable means of distinguishing between large objects (e.g., palms) from smaller objects (e.g., fingertips, thumbs and a stylus) is described.

Claims

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

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks, the filterng being distinct from the compensating;

segmenting the proximity image to identify a plurality of patches having patch pixel values;

reducing or down-scaling peripheral patch pixel values for one or more of the plurality of patches based on the compensated proximity image and the filtered proximity image, the reducing or down-scaling being distinct from the compensating and filtering;

determining an eccentricity value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

identifying a first patch as a thumb contact when the eccentricity value of the first patch is greater than a first threshold; and

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

2. The method of claim 1, further comprising, identifying the first patch as a fingertip contact when the eccentricity value of the first patch is less than the first threshold.

3. The method of claim 2, further comprising using the identified first patch as a fingertip contact to control an operation of the touch-surface device.

4. The method of claim 1, wherein the first threshold of the eccentricity value is between 1.0-1.5.

5. The method of claim 1, wherein the first threshold of the eccentricity value is 1.5.

6. The method of claim 1, wherein the first threshold is a linear function.

7. The method of claim 1, wherein the first threshold is a non-linear function.

8. The method of claim 1, further comprising identifying patches that are larger than thumb contacts, and ignoring the identified larger patches.

9. The method of claim 1, identifying a second patch as a fingertip contact when the eccentricity value of the second patch is less than the first threshold.

10. The method of claim 9, further comprising identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch.

11. The method of claim 10, further comprising using the identified first and second patches as associated with a right hand to control an operation of the touch-surface device.

12. The method of claim 9, further comprising identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch.

13. The method of claim 9, further comprising:

identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch;

identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch; and

performing a first action on the touch-surface device when the identified first and second patches are associated with a right hand; and

performing a second, different action on the touch-surface device when the identified first and second patches are associated with a left hand.

14. A touch-surface device, comprising:

a touch-surface adapted to receive touch input;

a processor coupled to the touch-surface; and

memory storing instructions to perform the method of claim 1.

15. The touch-surface device of claim 14, wherein the touch-surface device comprises one of a mobile telephone, a music device, a video display device and a personal computer.

19. 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.

20. 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.

16. Apparatus for discriminating input sources to a touch-surface device, comprising:

means for obtaining a proximity image;

means for compensating the proximity image for background noise;

means for filtering the proximity image to reduce spurious peaks, the filterng being distinct from the compensating;

means for segmenting the proximity image to identify a plurality of patches having patch pixel values;

means for reducing or down-scaling peripheral patch pixel values for one or more of the plurality of patches based on the compensated proximity image and the filtered proximity image, the reducing or down-scaling being distinct from the compensating and filtering;

means for determining an eccentricity value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

means for identifying a first patch as a thumb contact when the eccentricity value of the first patch is greater than a first threshold; and

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

17. Apparatus as recited in claim 16, further comprising means for identifying a second patch as a fingertip contact when the eccentricity value of the second patch is less than the first threshold.

18. Apparatus as recited in claim 17, further comprising:

means for identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch;

means for identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch; and

means for performing a first action on the touch-surface device when the identified first and second patches are associated with a right hand; and

means for performing a second, different action on the touch-surface device when the identified first and second patches are associated with a left hand.

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

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image;

segmenting the proximity image to identify a plurality of patches having patch pixel values;

reducing or down-scaling peripheral patch pixel values for one or more of the plurality of patches based on the compensated proximity image and the filtered proximity image;

determining an eccentricity value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

determining a minor radius value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

ignoring each patch having a minor radius value greater than a first threshold;

after ignoring each patch having a minor radius value greater than the first threshold, identifying a first patch as a thumb contact when the eccentricity value of the first patch is greater than a second threshold; and

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

22. The method of claim 21, further comprising, identifying the first patch as a fingertip contact when the eccentricity value of the first patch is less than the first threshold.

23. The method of claim 22, further comprising using the identified first patch as a fingertip contact to control an operation of the touch-surface device.

24. The method of claim 21, wherein the first threshold of the eccentricity value is between 1.0-1.5.

25. The method of claim 21, wherein the first threshold of the eccentricity value is 1.5.

26. The method of claim 21, wherein the first threshold is a linear function.

27. The method of claim 21, wherein the first threshold is a non-linear function.

28. The method of claim 21, further comprising identifying patches that are larger than thumb contacts, and ignoring the identified larger patches.

29. The method of claim 21, identifying a second patch as a fingertip contact when the eccentricity value of the second patch is less than the first threshold.

30. The method of claim 29, further comprising identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch.

31. The method of claim 30, further comprising using the identified first and second patches as associated with a right hand to control an operation of the touch-surface device.

32. The method of claim 29, further comprising identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch.

33. The method of claim 29, further comprising:

identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch;

identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch; and

performing a first action on the touch-surface device when the identified first and second patches are associated with a right hand; and

performing a second, different action on the touch-surface device when the identified first and second patches are associated with a left hand.

34. A touch-surface device, comprising:

a touch-surface adapted to receive touch input;

a processor coupled to the touch-surface; and

memory storing instructions to perform the method of claim 21.

35. The touch-surface device of claim 34, wherein the touch-surface device comprises one of a mobile telephone, a music device, a video display device and a personal computer.

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

means for obtaining a proximity image;

means for compensating the proximity image for background noise;

means for filtering the proximity image;

means for segmenting the proximity image to identify a plurality of patches having patch pixel values;

means for reducing or down-scaling peripheral patch pixel values for one or more of the plurality of patches based on the compensated proximity image and the filtered proximity image;

means for determining an eccentricity value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

means for determining a minor radius value for one or more of the reduced or down-scaled peripheral patch pixel values of the plurality of patches;

means for ignoring each patch having a minor radius value greater than a first threshold;

means for, after ignoring each patch having a minor radius value greater than the first threshold, identifying a first patch as a thumb contact when the eccentricity value of the first patch is greater than a second threshold; and

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

37. Apparatus as recited in claim 36, further comprising means for identifying a second patch as a fingertip contact when the eccentricity value of the second patch is less than the first threshold.

38. Apparatus as recited in claim 37, further comprising:

means for identifying the first and second patches as associated with a right hand when the identified first patch is to the left of the identified second patch;

means for identifying the first and second patches as associated with a left hand when the identified first patch is to the right of the identified second patch; and

means for performing a first action on the touch-surface device when the identified first and second patches are associated with a right hand; and

means for performing a second, different action on the touch-surface device when the identified first and second patches are associated with a left hand.

39. 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 36.

40. 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 36.