Time-synchronized pixel array and touch array crosstalk mitigation systems and methods
Systems, methods, and devices are described that may mitigate display pixel and touch crosstalk noise. A touch processing system may compensate touch scan data to reduce the noise based on a luminance value. An image processing system may determine the luminance value based on image data and a display brightness value of an electronic display. Using the compensated touch scan data, the touch processing system may determine a proximity of a capacitive object to at least one touch sense region of the electronic display.
1. A system comprising:
an electronic display configured to display image data and obtain touch scan data corresponding to at least one touch sense region of the electronic display;
an image processing system configured to:
receive an image frame data packet comprising the image data; and
determine statistical data corresponding to the at least one touch sense region of the electronic display based on the image data; and
a touch processing system configured to:
determine an estimated charge error expected to effect the touch scan data during a touch sensing operation based on the statistical data and a model of a multi-phase sensing operation;
compensate the touch scan data based on the estimated charge error to obtain compensated touch scan data; and
use the compensated touch scan data to determine a proximity of a capacitive object to the at least one touch sense region of the electronic display.
2. The system of claim 1 , wherein the image processing system is configured to generate the statistical data at least in part by:
dividing the image data into a plurality of cells of a pixel map respectively corresponding to a plurality of touch sense regions, wherein different portions of the image data correspond to different cells of the plurality of cells, wherein one cell of the plurality of cells comprises at least a portion of the image data, and wherein the plurality of touch sense regions comprise the at least one touch sense region; and
determining, for each cell of the plurality of cells, an average of luminance data corresponding to the image data for that respective cell, wherein the averaged luminance data is generated based on the statistical data.
3. The system of claim 2 , wherein the touch processing system is configured to compensate the touch scan data using the averaged luminance data and a global brightness value configured to indicate an overall light intensity of the electronic display.
4. The system of claim 3 , wherein the touch processing system is configured to compensate the touch scan data at least in part by determining a cathode impedance of the at least one touch sense region using the averaged luminance data and the global brightness value.
5. The system of claim 4 , wherein the cathode impedance comprises:
a first impedance corresponding to electronic display components connected directly to a cathode of one or more light emitting diodes (LEDs) of the electronic display; and
a second impedance corresponding to the LEDs and electronic drive circuitry configured to control the LEDs, wherein the second impedance varies based on an overall light intensity emitted from the electronic display.
6. The system of claim 1 , wherein determining the estimated charge error comprises using the model of the multi-phase sensing operation at least in part by:
determining a cathode impedance based on an average pixel luminance and a display brightness value of the statistical data;
applying the cathode impedance to a display-to-touch aggression model in which the cathode impedance and a sensing capacitor are coupled to a voltage source to charge the sensing capacitor; and
determining a first voltage across the sensing capacitor while the voltage source is coupled.
7. The system of claim 6 , wherein the model of the multi-phase sensing operation comprises:
decoupling the voltage source from the cathode impedance and the sensing capacitor;
coupling the cathode impedance and the sensing capacitor to an amplifier; and
determining a second voltage across the sensing capacitor while the amplifier is coupled.
8. The system of claim 6 , wherein parameters of the model of the multi-phase sensing operation are configured to be determined based on material properties of the electronic display and components of the electronic display.
9. The system of claim 8 , wherein the parameters are configured to be calibrated based on a process in which one or more devices are used to capture display-to-touch aggression characteristics for one or more display luminance values.
10. The system of claim 1 , wherein the statistical data comprises grey scale weighted current values.
11. A non-transitory, tangible, computer-readable medium comprising instructions that, when executed by a processor, are configured to cause a touch processing system to perform operations comprising:
receiving image frame statistics from image processing circuitry;
determining a cathode impedance based on the image frame statistics;
modeling a multi-phase sensing operation to determine a charge error based on the cathode impedance;
receiving touch scan data from an electronic display, wherein the electronic display is configured to obtain the touch scan data;
compensating the touch scan data using the charge error to obtain compensated touch scan data; and
using the compensated touch scan data to determine a proximity of a capacitive object to a touch sense region of the electronic display.
12. The computer-readable medium of claim 11 , wherein compensating the touch scan data comprises operations to:
determine a voltage error based on the charge error; and
subtract the voltage error from the touch scan data to obtain the compensated touch scan data.
13. The computer-readable medium of claim 12 , wherein receiving the image frame statistics comprises reading a buffer memory configured to store the image frame statistics after the image processing circuitry writes the image frame statistics to the buffer memory.
14. The computer-readable medium of claim 12 , wherein the image frame statistics comprises grey scale weighted current values.
15. The computer-readable medium of claim 11 , wherein the operations comprise:
receiving additional touch scan data corresponding to a next touch sensing operation performed while a second image frame is being presented via the electronic display; and
compensating the additional touch scan data based on replaying the image frame statistics, wherein the image frame statistics corresponds to previously presented image data of an image frame, and wherein replaying the image frame statistics is based on a synchronization circuitry and an alignment signal processed by a timing controller.
16. A device comprising:
an electronic display;
a first processing system coupled to the electronic display, wherein the first processing system is configured to:
receive an image frame data packet corresponding to a first image frame; and
generate statistical data based on the image frame data packet;
a memory coupled to the first processing system, wherein the memory receives the statistical data from the first processing system; and
a second processing system coupled to the memory and to the electronic display, wherein the second processing system is configured to:
read the statistical data from the memory;
receive touch scan data from the electronic display;
determine an amount of error expected to effect touch scan data during a touch sensing operation based on the statistical data and a display-to-touch aggression model;
adjust the touch scan data based on the amount of error and the statistical data to generate compensated touch scan data; and
determine a proximity of a capacitive object to at least one touch sense region of the electronic display based on the compensated touch scan data.
17. The device of claim 16 , wherein the statistical data comprises an average pixel luminance (APL) map of cells, a doorbell signal, and a frame status, wherein cells of the APL map of cells are configured to respectively correspond to different touch sense regions of the electronic display, and wherein each of the cells is configured to comprise a pixel luminance value that is an average of current values for each pixel associated with a touch sense region corresponding to that cell.
18. The device of claim 17 , wherein the display-to-touch aggression model is associated with a first charge error and a second charge error expected to occur in response to a tactile input, wherein the first charge error corresponds to a charging operation performed at a first time to a sensing capacitance based on a system resistance, and wherein the second charge error corresponds to discharging operation at a second time to the sensing capacitance based on the system resistance.
19. The device of claim 18 , wherein the second processing system is configured to synchronize the statistical data associated with the first image frame and the touch scan data acquired during presentation of the first image frame based on the doorbell signal.
20. The device of claim 18 , wherein the second processing system is configured to determine to repeat using the amount of error to compensate additional touch scan data based on the frame status.