Multi-touch input discrimination

• US 8,791,921 B2
• Filed: 08/19/2013
• Issued: 07/29/2014
• 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
• Application Number:
  US13/970,526
• Publication Number:
  US 20140049495A1
• Time in Patent Office: 344 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;

segmenting the proximity image to identify a plurality of patches;

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

identifying one of the plurality of patches as being associated with a large object if the minor axis radius value of the one or more of the plurality of patches 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 the large object comprises a cheek.

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

4. The method of claim 1, further comprising:

identifying a second patch of the plurality of patches as being associated with a palm if the minor axis 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 a touch-surface device.

5. The method of claim 4, further comprising:

identifying a third patch of the plurality of patches as being associated with a finger if the minor axis value of the third patch is less than the second specified threshold; and

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

6. The method of claim 1, wherein the act of obtaining comprises obtaining a proximity image from a capacitive touch-surface device.

7. The method of claim 1, wherein the act of obtaining comprises obtaining a proximity image from a pressure-sensitive touch-surface device.

8. The method of claim 1, wherein the act of filtering comprises spatially filtering the first proximity image.

9. The method of claim 8, wherein the act of spatially filtering comprises inserting a border around the first proximity image prior to spatially filtering the first proximity image.

10. The method of claim 1, wherein the act of filtering comprises temporally filtering the first proximity image with a second proximity image.

11. The method of claim 1, further comprising constraining pixel values associated with the filtered proximity image to be less than a specified value.

12. The method of claim 1, wherein the touch-surface device comprises one of the following devices:

tablet computer system, notebook computer system, portable music player, portable video player, personal digital assistant and mobile telephone.

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 claim 1.

14. 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.

15. The device in accordance with claim 14, wherein the portable electronic device comprises one of the following devices:

tablet computer system, notebook computer system, portable music player, portable video player, personal digital assistant and mobile telephone.

16. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a patch;

reducing or down-scaling peripheral patch pixel values for the patch based on the compensated proximity image and the filtered proximity image;

determining a minor axis radius value for the patch having reduced or down-scaled peripheral patch pixel values;

identifying the patch as being associated with a large object if the minor axis radius value of the patch is above a first specified threshold; and

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

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 16.

20. The method of claim 16, wherein the multi-touch touch-surface device comprises one of the following devices:

tablet computer system, notebook computer system, portable music player, portable video player, personal digital assistant and mobile telephone.

17. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a patch;

reducing or down-scaling peripheral patch pixel values for the patch based on the compensated proximity image and the filtered proximity image;

determining a minor axis radius value for the patch having reduced or down-scaled peripheral patch pixel values;

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

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

21. 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 17.

22. The method of claim 17, wherein the multi-touch touch-surface device comprises one of the following devices:

tablet computer system, notebook computer system, portable music player, portable video player, personal digital assistant and mobile telephone.

18. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a patch;

reducing or down-scaling peripheral patch pixel values for the patch based on the compensated proximity image and the filtered proximity image;

determining a minor axis radius value for the patch having reduced or down-scaled peripheral patch pixel values;

identifying a patch as being associated with a finger if the minor axis value of the patch is less than a first specified threshold; and

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

23. 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 18.

24. The method of claim 18, wherein the multi-touch touch-surface device comprises one of the following devices:

tablet computer system, notebook computer system, portable music player, portable video player, personal digital assistant and mobile telephone.

25. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a plurality of patches;

reducing or down-scaling peripheral patch pixel values for the patch based on the compensated proximity image and the filtered proximity image;

determining that at least five of the identified patches having reduced or down-scaled peripheral patch pixel values are associated with finger contacts to a touch-surface;

identifying the at least five identified patches as being associated with a finger-clasp operation; and

using the identified finger-clasp operation to control an operation of the multi-touch touch-surface device.

26. The method of claim 25, wherein the multi-touch touch-surface device comprises one of the devices selected from the group consisting of:

a tablet computer system, a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.

27. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a plurality of patches;

reducing or down-scaling peripheral patch pixel values for the patch based on the compensated proximity image and the filtered proximity image;

determining that at least two of the identified patches having reduced or down-scaled peripheral patch pixel values have major axis radius values larger than approximately 15 millimeters;

identifying the at least two identified patches as being associated with a finger-clasp operation; and

using the identified finger-clasp operation to control an operation of the multi-touch touch-surface device.

28. The method of claim 27, wherein the multi-touch touch-surface device comprises one of the devices selected from the group consisting of:

a tablet computer system, a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.

29. A method to identify an input source 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;

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

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

determining a signal density value for at least one of the one or more patches;

identifying the at least one patch having reduced or down-scaled peripheral patch pixel values as being associated with an object contacting a touch-surface of a touch-surface device if the at least one patch has a signal density value greater than a specified value;

identifying the at least one patch as being associated with an object hovering above the touch-surface if the at least one patch has a signal density value less than the specified value; and

performing a control operation on the touch-surface device in response to the acts of identifying.

30. The method of claim 29, wherein the signal density value is determined by dividing the sum of all pixel values in a patch by the number of pixels in the patch.

31. The method of claim 29, wherein the signal density value is determined by dividing the sum of all pixel values in a patch by a radius of the patch.

32. The method of claim 31, wherein the radius of the patch comprises a geometric mean radius of the patch.

33. The method of claim 29, wherein the signal density value is determined by dividing the sum of all pixel values in a patch by the patches'"'"' area.

34. The method of claim 29, wherein the control operation comprises causing the touch-surface device to change an operational state.

35. The method of claim 29, wherein the control operation comprises performing a specified function.

36. The method of claim 29, wherein the control operation comprises ignoring the object contacting the touch-surface.

37. The method of claim 29, wherein the touch-surface device comprises one of the devices selected from the group consisting of:

a tablet computer system, a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.

38. 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 29.

39. A method to identify an input source to a multi-touch touch-surface device, comprising:

obtaining a proximity image;

compensating the proximity image for background noise;

filtering the proximity image to reduce spurious peaks;

segmenting the proximity image to identify a plurality of patches;

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

determining that at least two of the identified patches having reduced or down-scaled peripheral patch pixel values have major axis radius values larger than a threshold;

identifying the at least two identified patches as being associated with a finger-clasp operation; and

using the identified finger-clasp operation to control an operation of the multi-touch touch-surface device.

40. The method of claim 39, wherein the multi-touch touch-surface device comprises one of the devices selected from the group consisting of:

a tablet computer system, a hand-held computer system, a portable music player system, a portable video player system and a mobile telephone.