Identifying hover and/or palm input and rejecting spurious input for a touch panel

• US 10,031,618 B2
• Filed: 07/10/2015
• Issued: 07/24/2018
• Est. Priority Date: 06/09/2011
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Mohindra, Rishi
• Primary Examiner(s): Xie, Kwin
• Application Number:
  US14/796,968
• Publication Number:
  US 20160188110A1
• Time in Patent Office: 1,110 Days
• Field of Search: 345173-174
• 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 2203/04108 Touchless 2D- 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 without distance measurement in the Z direction
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A touch panel controller may include a communications module configured to receive pixel values, where each pixel value represents a capacitance associated with a pixel formed at a drive electrode and a sensor electrode of a touch panel. The touch panel controller may also include a processing module configured to discard pixel values below a noise threshold, discard pixel values for non-zero pixels that are not adjacent to non-zero pixels, reject detected input for pixel values associated with a palm input, compute an initial centroid associated with the pixel values, reject detected input for pixel values associated with a hover input, and provide detected input that is not associated with palm input or hover input.

Claims

1. A touch panel controller comprising:

a communications module configured to receive a first plurality of pixel values, each pixel value of the first plurality of pixel values representing a capacitance associated with a respective pixel of a plurality of pixels formed at a respective intersection of a drive electrode and a sensor electrode of a touch panel; and

a processing module communicatively coupled with the communications module and configured to;

identify a peak pixel value from the first plurality of pixel values;

detect an input based on the identified peak pixel value;

discard pixel values of the first plurality of pixel values that are below a first threshold,

discard pixel values of the first plurality of pixel values that are above the first threshold and that are not adjacent to at least one other pixel value above the first threshold,

determine a number of pixel values remaining in the first plurality of pixel values after the discardings that are associated with the detected input;

determine an aspect ratio for the detected input based on the identified peak pixel value and the determined number of pixel values, wherein determining the aspect ratio includes performing a 1/e thresholding operation relative to the identified peak pixel value;

determine whether the detected input is associated with a touch input or a hover input based on the aspect ratio; and

provide or reject the detected input based on the determination of whether the detected input is associated with a touch input or a hover input.

2. The touch panel controller as recited in claim 1, wherein the processing module is further configured to:

associate at least one of the first plurality of pixel values with a finger touch;

increase the first threshold; and

discard pixel values of the first plurality of pixel values that are below the increased first threshold.

3. The touch panel controller as recited in claim 1, wherein the processing module is further configured to weight a filter for a first pixel value associated with a pixel at a first respective pixel location based upon identifying a touch at a second pixel location separated from and non-adjacent to the first pixel location.

4. The touch panel controller as recited in claim 1, wherein the processing module is further configured to use specific absorption rate (SAR) proximity detection to identify the presence of the palm in proximity to the touch panel.

12. The touch panel controller as recited in claim 1, wherein the processing unit is further configured to:

associate pixel values of the first plurality of pixel values that are above the first threshold and that are adjacent to at least one other pixel value above the first threshold with a glob;

determine whether the glob is associated with an irregular input; and

if the glob is associated with an irregular input;

decrease the first threshold;

rescan the plurality of pixels;

receive a second plurality of pixel values based on the rescan;

associate pixel values of the second plurality of pixel values that are above the decreased first threshold and that are adjacent to at least one other pixel value of the second plurality of pixel values above the decreased first threshold with the glob; and

reject the irregular input associated with the glob.

13. The touch panel controller as recited in claim 12, wherein to determine whether the glob is associated with an irregular input, the processing module is configured to:

determine a number of pixels associated with the glob; and

if the determined number of pixels associated with the glob is greater than a second threshold, determine that the glob is associated with an irregular input.

14. The touch panel controller as recited in claim 12, wherein to determine whether the glob is associated with an irregular input, the processing module is configured to:

perform specific absorption rate (SAR) proximity detection to determine whether an irregular object is in proximity to the touch panel.

18. The touch panel controller as recited in claim 12, wherein the processing module is further configured to merge the glob with an adjacent glob.

5. A method comprising:

scanning a plurality of pixels of a touch panel, each pixel of the plurality of pixels being formed at a respective intersection of a drive electrode and a sensor electrode;

receiving a first plurality of pixel values based on the scanning, each pixel value of the first plurality of pixel values representing a capacitance associated with a respective pixel of the plurality of pixels;

discarding pixel values of the first plurality of pixel values that are below a first threshold;

discarding pixel values of the first plurality of pixel values that are above the first threshold and that are not adjacent to at least one other pixel value above the first threshold;

associating pixel values of the first plurality of pixel values that are above the first threshold and that are adjacent to at least one other pixel value above the first threshold with a glob;

determining whether the glob is associated with an irregular input; and

if the glob is associated with an irregular input;

decreasing the first threshold;

rescanning the plurality of pixels;

receiving a second plurality of pixel values based on the rescanning;

associating pixel values of the second plurality of pixel values that are above the decreased first threshold and that are adjacent to at least one other pixel value of the second plurality of pixel values above the decreased first threshold with the glob; and

rejecting the irregular input associated with the glob.

6. The method as recited in claim 5, further including:

associating at least one of the first plurality of pixel values with a finger touch;

increasing the first threshold; and

discarding pixel values of the first plurality of pixel values that are below the increased first threshold.

7. The method as recited in claim 5, wherein discarding pixel values above the first threshold that are not adjacent to at least one other pixel value above the first threshold comprises weighting a filter for a first pixel value associated with a pixel at a first respective pixel location based upon identifying a touch at a second pixel location separated from the first pixel location.

8. The method as recited in claim 5, further including merging the glob with an adjacent glob.

9. The method as recited in claim 5, further comprising:

identifying the presence of a palm in proximity to the touch panel based on specific absorption rate (SAR) proximity detection.

15. The method of claim 5, wherein determining whether the glob is associated with an irregular input includes:

determining a number of pixels associated with the glob; and

if the determined number of pixels associated with the glob is greater than a second threshold, determining that the glob is associated with an irregular input.

16. The method of claim 5, wherein determining whether the glob is associated with an irregular input includes performing specific absorption rate (SAR) proximity detection to determine whether an irregular object is in proximity to the touch panel.

10. A method comprising:

receiving a plurality of pixel values, each pixel value of the plurality of pixel values representing a capacitance associated with a respective pixel of a plurality of pixels formed at a respective intersection of a drive electrode and a sensor electrode of a touch panel;

identifying a peak pixel value from the plurality of pixel values;

detecting an input based on the identified peak pixel value;

discarding pixel values of the plurality of pixel values that are below a first threshold;

discarding pixel values of the plurality of pixel values that are above the first threshold and that are not adjacent to at least one other pixel value above the first threshold;

determining a number of pixel values remaining in the first plurality of pixel values after the discardings that are associated with the detected input;

determining an aspect ratio for the detected input based on the identified peak pixel value and the determined number of pixel values, wherein determining the aspect ratio includes performing a 1/e thresholding operation relative to the identified peak pixel value;

determining whether the detected input is associated with a touch input or a hover input based on the aspect ratio; and

providing or rejecting the detected input based on the determination of whether the detected input is associated with a touch input or a hover input.

11. The method as recited in claim 10, wherein discarding pixel values above the first threshold that are not adjacent to at least one other pixel value above the first threshold comprises weighting a filter for a first pixel value associated with a pixel at a first respective pixel location based upon identifying a touch at a second pixel location separated from the first pixel location.

17. The method as recited in claim 10, further including determining a centroid for the detected input, wherein the determining of whether the detected input is associated with a touch input or a hover input is further based on a position of the centroid on the touch panel.