NOISE REDUCTION METHOD AND SYSTEM FOR TOUCH DETECTION DEVICE

• US 20120249433A1
• Filed: 05/20/2011
• Published: 10/04/2012
• Est. Priority Date: 03/28/2011
• Status: Active Grant

• Current Assignee: Shenzhen Goodix Technology Co., Ltd.
• Original Assignee: Shenzhen Goodix Technology Co., Ltd.
• Inventors: Deng, Gengchun, Chen, Xiaoxiang
• Granted Patent: US 8,570,293 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer

Abstract

Noise reduction method and system for a touch detection device are disclosed. The noise reduction method includes: step A, performing a synchronous sampling on the touch detection nodes in one same group and storing the sampling data; step B, comparing each sampling data against a corresponding reference data to calculate a differential data which, as a detection data, replaces a corresponding original sampling data; step C, calculating statistics of the replacing detection data to screen out valid data to calculate a DC offset component indicative of a noise ingredient; and step D, obtaining noise-filtered detection data by subtracting the DC offset component from each detection data.

Claims

1. A noise reduction method for a touch detection device, wherein touch detection nodes of the touch detection device are divided into one or more groups and the noise reduction method comprises:

step A, performing a synchronous sampling on the touch detection nodes in one same group and storing the sampling data;

step B, comparing each sampling data against a corresponding reference data to calculate a differential data which, as a detection data, replaces a corresponding original sampling data;

step C, calculating statistics of the replacing detection data obtained at step B to screen out, according to a predetermined screening condition, valid data to calculate a DC offset component indicative of a noise ingredient; and

step D, obtaining noise-filtered detection data by subtracting the DC offset component obtained at step C from each detection data obtained at step B.

2. The noise reduction method according to claim 1, wherein step C further comprises:

step C21, setting a threshold value to determine the validity of a data; and

setting distribution scales for statistics of detection data distribution;

step C22, calculating the distribution statistics of a group of detection data obtained at step B;

step C23, identifying a most concentrated data distribution scale and a second most concentrated data distribution scale;

step C24, determining whether the amplitude of an average of the data in the most concentrated data distribution scale is larger than the threshold value;

step C25, if the determination result of step C24 is yes, further determining whether the amplitude of an average of the data in the second most concentrated data distribution scale is less than the amplitude of the average of the data in the most concentrated data distribution scale;

step C26, if the determination result of step C25 is yes, considering the average of the data in the second most concentrated data distribution scale as the DC offset component; and

step C27, if either the determination result of step C24 or the determination result of step C25 is no, considering the average of the data in the most concentrated data distribution scale as the DC offset component.

3. The noise reduction method according to claim 1, wherein step C further comprises:

step C31, setting a dividing value for screening out valid data;

step C32, calculating an average of a group of detection data obtained at step B;

step C33, screening out valid data from the detection data according to the dividing value set at step C31 and the average obtained at step C32 such that the valid data screened out are located not beyond a scope centered at the average and having an amplitude of the dividing value with respect to the average; and

step C34, calculating an average of the data screened out at step C33, the obtained average being considered as the desired DC offset component.

4. The noise reduction method according to claim 1, wherein step C further comprises:

step C41, setting distribution scales for statistics of detection data;

step C42, calculating the distribution statistics of a group of detection data obtained at step B;

step C43, identifying a most concentrated detection data distribution scale; and

step C44, calculating an average of the data in the most concentrated scale, the obtained average being considered as the desired DC offset component.

5. A noise reduction system for a touch detection device, touch detection nodes of the touch detection device being divided into one or more groups, the noise reduction system comprising:

a sampling unit configured to perform a synchronous sampling on the touch detection nodes belonging to the same group and store the sampling data;

a differential value calculating unit configured to compare each sampling data against a corresponding reference data to calculate a differential data to replace a corresponding original sampling data;

a noise calculating unit configured to calculate statistics of the replacing detection data obtained by the differential value calculating unit to screen out, according to a predetermined screening condition, valid data to calculate a DC offset component indicative of a noise ingredient; and

a noise filtering unit configured to obtain noise-filtered detection data by subtracting the DC offset component obtained by the noise calculating unit from each detection data calculated by the differential value calculating unit.

6. The noise reduction system according to claim 5, wherein the noise calculating unit comprises:

a threshold and distribution scale setting module configured to set a threshold value for determining the validity of a data and distribution scales for statistics of detection data distribution;

a detection data statistics module configured to calculate the distribution statistics of a group of replacing detection data obtained by the differential value calculating unit;

a first judging module configured to judge whether the amplitude of an average of detection data in a most concentrated data distribution scale is greater than the threshold value;

a second judging module configured to further judge whether the amplitude of an average of detection data in a second most concentrated data distribution scale is less than the amplitude of the average of the detection data in the most concentrated scale if the result of the judgment made by the first judging module is yes; and

a DC offset component determining module configured to consider the average of the detection data in the second most concentrated scale as the DC offset component if the result of the judgment made by the second judging module is yes, or consider the average of the detection data in the most concentrated scale as the DC offset component if the result of the judgment made by the first judging module or by the second judging module is no.

7. The noise reduction system according to claim 5, wherein the noise calculating unit comprises:

a valid data dividing value setting module configured to set a dividing value for screening valid data;

an average calculating module configured to calculate an average of the group of detection data;

a valid data screening module configured to screen out valid data from the detection data according to the dividing value set by the valid data dividing value setting module and the average obtained by the average calculating module such that the valid data screened out are located not beyond a scope centered at the average and having an amplitude of the dividing value with respect to the average; and

a DC offset component determining module configured to calculate an average of the data screened out by the valid data screening module, the average obtained being considered as the desired DC offset component.

8. The noise reduction system according to claim 5, wherein the noise calculating unit comprises:

a distribution scale setting module configured to set distribution scales for statistics of detection data;

a distribution scale statistics module configured to calculate the distribution statistics of a group of replacing detection data obtained by the differential value calculating unit; and

a DC offset component determining module configured to calculate an average of data in a most concentrated data distribution scale obtained by the distribution scale statistics module, the average obtained being considered as the desired DC offset component.

9. A touch terminal comprising a touch detection device, the touch detection device comprising:

a touch sensor unit; and

a touch controller unit coupled to the touch sensor unit, wherein the touch controller unit comprises a noise reduction system, touch detection nodes of the touch detection device being divided into one or more groups, the noise reduction system comprising;

a sampling unit configured to perform a synchronous sampling on the touch detection nodes belonging to the same group and store the sampling data;

a differential value calculating unit configured to compare each sampling data against a corresponding reference data to calculate a differential data to replace a corresponding original sampling data;

a noise calculating unit configured to calculate statistics of the replacing detection data obtained by the differential value calculating unit to screen out, according to a predetermined screening condition, valid data to calculate a DC offset component indicative of a noise ingredient; and

a noise filtering unit configured to obtain noise-filtered detection data by subtracting the DC offset component obtained by the noise calculating unit from each detection data calculated by the differential value calculating unit.

10. The touch terminal according to claim 9, wherein the noise calculating unit comprises:

a threshold and distribution scale setting module configured to set a threshold value for determining the validity of a data and distribution scales for statistics of detection data;

a detection data statistics module configured to calculate the distribution statistics of a group of replacing detection data obtained by the differential value calculating unit;

a first judging module configured to judge whether the amplitude of an average of detection data in a most concentrated data distribution scale is greater than the threshold value;

a second judging module configured to further judge whether the amplitude of an average of detection data in a second most concentrated data distribution scale is less than the amplitude of the average of the detection data in the most concentrated scale if the result of the judgment made by the first judging module is yes; and

a DC offset component determining module configured to consider the average of the detection data in the second most concentrated scale as the DC offset component if the result of the judgment made by the second judging module is yes, or consider the average of the detection data in the most concentrated scale as the DC offset component if the result of the judgment made by the first judging module or by the second judging module is no.

11. The touch terminal according to claim 9, wherein the noise calculating unit comprises:

a valid data dividing value setting module configured to set a dividing value for screening valid data;

an average calculating module configured to calculate an average of the group of detection data;

a valid data screening module configured to screen out valid data from the detection data according to the dividing value set by the valid data dividing value setting module and the average obtained by the average calculating module such that the valid data screened out are located not beyond a scope centered at the average and having an amplitude of the dividing value with respect to the average; and

a DC offset component determining module configured to calculate an average of the data screened out by the valid data screening module, the average obtained being considered as the desired DC offset component.

12. The touch terminal according to claim 9, wherein the noise calculating unit comprises:

a distribution scale setting module configured to set distribution scales for statistics of detection data;

a distribution scale statistics module configured to calculate the distribution statistics of a group of replacing detection data obtained by the differential value calculating unit; and

a DC offset component determining module configured to calculate an average of data in a most concentrated data distribution scale obtained by the distribution scale statistics module, the average obtained being considered as the desired DC offset component.