Method and associated controller for adaptively adjusting touch control threshold

• US 9,939,957 B2
• Filed: 11/05/2015
• Issued: 04/10/2018
• Est. Priority Date: 08/28/2015
• Status: Expired due to Fees

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: MStar Semiconductor Incorporated (MediaTek, Inc.)
• Inventors: Chiang, Ching-Chun
• Primary Examiner(s): SOTO LOPEZ, JOSE R
• Application Number:
  US14/933,105
• Publication Number:
  US 20170060335A1
• Time in Patent Office: 887 Days
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A method for adaptively adjusting a touch control threshold of a touch panel is provided. The method includes: receiving a set of sample values from the touch panel; calculating a mean value and a standard deviation based on the set of sample values according to a determination result indicating that the set of sample values are not greater than the touch control threshold; and updating the touch control threshold according to the mean value and the standard deviation.

Claims

1. A method for adaptively adjusting a touch control threshold, applied to a touch panel, the method comprising:

obtaining a set of sample values from the touch panel;

determining whether each of the set of sample values is not greater than the tough panel control threshold;

updating the touch control threshold, which is used to compare with a sample value, using a mean value and a standard deviation of the set of sample values according to a determination result indicating that each of the set of sample values is not greater than the touch control threshold;

obtaining another set of sample values from the touch panel, wherein the another set of sample values comprise a set of adjacent sample values, and all sample values in the set of adjacent sample values are greater than the updated touch control threshold;

generating an area of a touch point according to the number of sample values in the set of adjacent sample values;

generating an area threshold according to an average difference between the set of adjacent sample values and the updated touch control threshold;

updating a subsisting count value of the touch point according to a determination result indicating that the area of the touch point is greater than the area threshold;

determining that the touch point is a valid touch point according to a determination result indicating that the subsisting count value is greater than a subsisting threshold; and

generating the subsisting threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold.

2. The method according to claim 1, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

generating a reference threshold according to a linear combination of the mean average and the standard deviation; and

updating the touch control threshold according to a weighted superimposition of the reference threshold and the touch control threshold.

3. The method according to claim 1, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

generating a reference threshold according to a linear combination of the mean value and the standard deviation; and

updating the touch control threshold according to a moving average of the reference threshold and a previous reference threshold.

4. The method according to claim 1, wherein the step of generating the area threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold comprises:

decreasing the area threshold according to a determination result indicating that the average difference is increased.

5. The method according to claim 1, wherein the step of generating the subsisting threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold comprises:

decreasing the subsisting threshold according to a determination result indicating that the average difference is increased.

6. The method according to claim 1, further comprising:

obtaining still another set of sample values from the touch panel, wherein the still another set of sample values comprise one or multiple sets of adjacent sample values, and all sample values in the one or multiple sets of adjacent sample values are greater than the updated touch control threshold;

generating an area/areas of one or multiple touch points according to the number of sample values in the one or multiple sets of adjacent sample values;

calculating another mean value and another standard deviation based on the still another set of sample values according to a determination result indicating that the areas of the one or multiple touch points are all smaller than an area threshold; and

updating the updated touch control threshold according to the another mean value and the another standard deviation.

7. The method according to claim 1, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

updating the touch control threshold based on the mean value and a predetermined standard deviation according to a determination result indicating that the standard deviation is smaller than a standard deviation threshold.

8. A controller, applied to a touch panel, the controller comprising:

an interface circuit, coupled to the touch panel; and

a core circuit, coupled to the interface circuit, performing steps of;

obtaining a set of sample values from the touch panel;

determining whether each of the set of sample values is not greater than the touch control threshold;

updating the touch control threshold, which is used to compare with a sample value, using a mean value and a standard deviation of the set of sample values according to a determination result indicating that each of the set of sample values is not greater than the touch control threshold;

obtaining another set of sample values from the touch panel, wherein the another set of sample values comprise a set of adjacent sample values, and all sample values in the set of adjacent sample values are greater than the updated touch control threshold;

generating an area of a touch point according to the number of sample values in the set of adjacent sample values;

generating an area threshold according to an average difference between the set of adjacent sample values and the updated touch control threshold;

updating a subsisting count value of the touch point according to a determination result indicating that the area of the touch point is greater than the area threshold;

determining that the touch point is a valid touch point according to a determination result indicating that the subsisting count value is greater than a subsisting threshold; and

generating the subsisting threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold.

9. The controller according to claim 8, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

generating a reference threshold according to a linear combination of the mean average and the standard deviation; and

updating the touch control threshold according to a weighted superimposition of the reference threshold and the touch control threshold.

10. The controller according to claim 8, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

generating a reference threshold according to a linear combination the mean value and the standard deviation, and updating the touch control threshold according to a moving average of the reference threshold and a previous reference threshold.

11. The controller according to claim 8, wherein the step of generating the area threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold comprises:

decreasing the area threshold according to a determination result indicating that the average difference is increased.

12. The controller according to claim 8, wherein the step of generating the subsisting threshold according to the average difference between the set of adjacent sample values and the updated touch control threshold comprises:

decreasing the subsisting threshold according to a determination result indicating that the average difference is increased.

13. The controller according to claim 8, wherein the core circuit further performs steps of:

obtaining still another set of sample values from the touch panel, wherein the still another set of sample values comprise one or multiple sets of adjacent sample values, and all sample values in the one or multiple sets of adjacent sample values are greater than the updated touch control threshold;

generating areas of one or multiple touch points according to the number of sample values in the one or multiple sets of adjacent sample values;

calculating another mean value and another standard deviation according to the still another set of sample values and a determination result indicating that the areas of the one or multiple touch points are smaller than an area threshold; and

updating the updated touch control threshold according to the another mean value and the another standard deviation.

14. The controller according to claim 8, wherein the step of updating the touch control threshold using the mean value and the standard deviation comprises:

updating the touch control threshold based on the mean value and a predetermined standard deviation according to a determination result indicating that the standard deviation is smaller than a standard deviation threshold.