Hover rejection through dynamic thresholding

• US 10,481,723 B2
• Filed: 10/28/2016
• Issued: 11/19/2019
• Est. Priority Date: 10/28/2016
• Status: Active Grant

• Current Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Ponnarasu, Manivannan, Nagarajan, Mythreyi
• Primary Examiner(s): Ahn, Sejoon
• Application Number:
  US15/337,167
• Publication Number:
  US 20180121010A1
• Time in Patent Office: 1,117 Days
• 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 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Disclosed herein is a touch screen controller that calculates a variance of an island in acquired touch data values. Where the variance exceeds a variance threshold, the island is validated as a representing touch. Where the variance does not exceed the variance threshold, whether the island represents a touch or a hover is determined by calculating a sharpness by applying weights to nodes of the island, where neighboring nodes adjacent to a peak node are weighted less than non-neighboring nodes not adjacent to the peak node. An island strength threshold is determined as a function of a product of the variance and the sharpness. It is determined that the island represents a touch where a highest touch data value of the island is greater than the island strength threshold, and a hover where the highest touch data value of the island is less than the island strength threshold.

Claims

1. An electronic device, comprising:

a touch screen controller configured to;

acquire touch data values;

locate an island in the acquired touch data values, the island being a set comprised of touch data values of the acquired touch data values that indicate a potential touch by being above a touch threshold value;

calculate a variance of the island, wherein the variance of the island indicates how far the touch data values of the set are separated from a mean of the set;

if the variance exceeds a variance threshold, validate the island as a representing touch; and

if the variance does not exceed the variance threshold, determine whether the island represents a touch or a hover by;

calculating a sharpness by applying weights to nodes of the island, wherein neighboring nodes adjacent to a peak node are weighted less than non-neighboring nodes not adjacent to the peak node, wherein each node of the island is a touch data value of the set;

determining an island strength threshold based upon multiplying the variance by the sharpness;

determining that the island represents a touch where a highest touch data value of the island is greater than the island strength threshold, and

determining that the island represents a hover where the highest touch data value of the island is less than the island strength threshold.

2. The electronic device of claim 1, wherein the touch screen controller applies weights to nodes of the island by:

applying a first weight to the peak node;

applying a second weight to the neighboring nodes; and

applying a third weight to the non-neighboring nodes;

wherein the second weight is less than the third weight.

3. The electronic device of claim 2, wherein the third weight is less than the first weight.

4. The electronic device of claim 2, wherein the touch screen controller calculates the sharpness as:

5. The electronic device of claim 4, wherein Weight1 is 1.5, Weight2 is 0.5, and Weight3 is 1.25.

6. The electronic device of claim 1, wherein the touch screen controller is further configured to normalize the sharpness;

and wherein the touch screen controller determines the island strength threshold as a function of a product of the variance and the normalized sharpness.

7. The electronic device of claim 6, wherein normalize the sharpness comprises a peak normalizing.

8. The electronic device of claim 7, wherein the peak normalizing comprises a five point peak normalizing.

9. The electronic device of claim 1, wherein the island is a three node by three node island.

10. An electronic device, comprising:

a touch screen; and

a touch screen controller coupled to the touch screen and configured to;

acquire touch data values;

locate an island in the acquired touch data values, the island being a set comprised touch data values of the acquired touch data values that indicate a potential touch of a touch screen by being above a touch threshold value; and

calculate a variance of the island, wherein the variance of the island indicates how far the touch data values of the set are separated from a mean of the set;

if the variance exceeds a variance threshold, validate the island as a representing touch; and

if the variance does not exceed the variance threshold, determine whether the island represents a touch or a hover by;

calculating a sharpness by applying weights to nodes of the island, wherein a neighboring node that is adjacent to a peak node containing a peak acquired touch data value is weighted less than a non-neighboring node that is not adjacent to the peak node, wherein each node of the island is a touch data value of the set;

multiplying the variance by the sharpness;

determining an island strength threshold as a function of the multiplication of the variance by the sharpness;

determining that the island represents a touch where a highest touch data value of the island is greater than the island strength threshold; and

determining that the island represents a hover where the highest touch data value of the island is less than the island strength threshold.

11. The electronic device of claim 10, wherein the touch screen controller applies weights to nodes of the island by:

applying a first weight to the peak node;

applying a second weight to the neighboring node;

applying a third weight to the non-neighboring node; and

wherein the second weight is less than the third weight.

12. The electronic device of claim 11, wherein the third weight is less than the first weight.

13. The electronic device of claim 11, wherein the touch screen controller calculates the sharpness as:

14. The electronic device of claim 13, wherein Weight1 is 1.5, Weight2 is 0.5, and Weight3 is 1.25.

15. A method, comprising:

acquire touch data values;

locate an island in the acquired touch data values, the island being a set comprised of touch data values of the acquired touch data values that indicate a potential touch by being above a touch threshold value;

calculate a variance of the island, wherein the variance of the island indicates how far the touch data values of the set are separated from a mean of the set;

if the variance exceeds a variance threshold, validate the island as a representing touch; and

if the variance does not exceed the variance threshold, determine whether the island represents a touch or a hover by;

calculating a sharpness by applying weights to nodes of the island, wherein neighboring nodes adjacent to a peak node are weighted less than non-neighboring nodes not adjacent to the peak node, wherein each node of the island is a touch data value of the set;

determining an island strength threshold based upon multiplying product of the variance by the sharpness;

determining that the island represents a touch where a highest touch data value of the island is greater than the island strength threshold; and

determining that the island represents a hover where the highest touch data value of the island is less than the island strength threshold.

16. The method of claim 15, wherein weights are applied to nodes of the island by:

applying a first weight to the peak node;

applying a second weight to the neighboring nodes;

applying a third weight to the non-neighboring nodes; and

wherein the second weight is less than the third weight.

17. The method of claim 16, wherein the third weight is less than the first weight.

18. The method of claim 16, wherein the sharpness is calculated as:

19. The method of claim 18, wherein Weight1 is 1.5, Weight2 is 0.5, and Weight3 is 1.25.

20. The method of claim 15, further comprising normalizing the sharpness;

and wherein the island strength threshold is determined as a function of a product of the variance and the normalized sharpness.

21. The method of claim 20, wherein the normalizing comprises a peak normalizing.

22. The method of claim 21, wherein the peak normalizing comprises a five point peak normalizing.