MULTI-TOUCH INPUT DISCRIMINATION

• US 20150199070A1
• Filed: 03/25/2015
• Published: 07/16/2015
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: WESTERMAN, Wayne Carl
• Granted Patent: US 9,256,322 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 major axis radius value for at least one patch having a reducing or down-scaling peripheral patch pixel value;

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 having a reducing or down-scaling peripheral patch pixel value;

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.

10. 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 claim 1.

11. 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.

12. The non-transitory program storage device of claim 11 wherein the instructions stored thereon further cause the programmable control device to perform the steps of:

identifying a second patch having a reducing or down-scaling peripheral patch pixel value, the second patch being associated with a palm when 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.

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

14. The method of claim 13, wherein the act of spatially filtering comprises inserting a border around the proximity image prior to spatially filtering the proximity image.

15. The method of claim 13, wherein the act of filtering comprises temporally filtering a first proximity image with a second proximity image.

16. 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.

8. An 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;

means for segmenting the proximity image to identify a plurality of patches;

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 a major axis radius value for at least one patch having a reducing or down-scaling peripheral patch pixel value;

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.

9. The apparatus of claim 8, further comprising:

means for determining a major axis radius value for a second patch having a reducing or down-scaling peripheral patch pixel value;

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.

17. 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 one of a major axis radius value and a geometric mean radius value for at least one patch;

having a reducing or down-scaling peripheral patch pixel value;

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 having a reducing or down-scaling peripheral patch pixel value;

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.

18. The method of claim 17, further comprising:

determining one of a major axis radius value and a geometric mean radius value for a third patch having a reducing or down-scaling peripheral patch pixel value;

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.

19. The method of claim 18, wherein the patch associated with the finger comprises a patch associated with a thumb.

20. An 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;

means for segmenting the proximity image to identify a plurality of patches;

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

having a reducing or down-scaling peripheral patch pixel value;

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 having a reducing or down-scaling peripheral patch pixel value;

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.

21. The apparatus of claim 20, further comprising:

means for determining one of a major axis radius value and a geometric mean radius value for a third patch having a reducing or down-scaling peripheral patch pixel value;

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.

22. 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 geometric mean radius value for the at least one patch having a reducing or down-scaling peripheral patch pixel value, 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.

23. The method of claim 22 further comprising:

determining a geometric mean radius value for a second patch having a reducing or down-scaling peripheral patch pixel value;

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.

24. The method of claim 23, further comprising:

determining a geometric mean radius value for a third patch having a reducing or down-scaling peripheral patch pixel value;

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. A portable electronic device, comprising:

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

processing means for performing acts in accordance to claim 22.

28. 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 22.

29. The non-transitory program storage device of claim 28 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.

25. An 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;

means for segmenting the proximity image to identify a plurality of patches;

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 a geometric mean radius value for the at least one patch having a reducing or down-scaling peripheral patch pixel value, 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.

26. The apparatus of claim 25, further comprising:

means for determining a geometric mean radius value for a second patch having a reducing or down-scaling peripheral patch pixel value;

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.

30. 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 size parameter value of a size parameter, the size parameter value indicative of a size of each of the at least one patch, having a reducing or down-scaling peripheral patch pixel value, 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 at least one patch;

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.

31. 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 30.

32. An apparatus 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 to reduce spurious peaks;

means for segmenting the proximity image to identify a plurality of patches;

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 a size parameter value of a size parameter, the size parameter value indicative of a size of each of the plurality of patches having reducing or down-scaling peripheral patch pixel values, 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.