Probabilistic latency modeling

• US 9,030,437 B2
• Filed: 08/08/2011
• Issued: 05/12/2015
• Est. Priority Date: 01/24/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Uzelac, Aleksandar, Stevens, David A., Zhao, Weidong, Shigemitsu, Takahiro, Willoughby, Briggs A., Pierce, John Graham, Santiago, Pravin Kumar, Ranta, Craig S., Wright, Timothy Allen, Maier, Jeffrey C., Perry, Robert T., Kirilov, Stanimir Naskov, Batchvarov, Andrey B.
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Edwards, Carolyn R
• Application Number:
  US13/205,319
• Publication Number:
  US 20120188197A1
• Time in Patent Office: 1,373 Days
• Field of Search: 345156-184, 703/4, 703 13- 22
• US Class Current: 345/174
• CPC Class Codes: G06F 11/2221 to test input/output devices or peripheral units
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

Touchscreen testing techniques are described. In one or more implementations, a piece of conductor (e.g., metal) is positioned as proximal to a touchscreen device and the touchscreen device is tested by simulating a touch of a user. This technique may be utilized to perform a variety of different testing of a touchscreen device, such as to test latency and probabilistic latency. Additional techniques are also described including contact geometry testing techniques.

Claims

1. A method implemented by one or more computing devices, the method comprising:

modeling latency of a touchscreen device using parameterized statistics by;

obtaining data describing end-to-end latency measurements of the touchscreen device to recognize a touch input; and

fitting the data to parametric distributions.

2. A method as described in claim 1, wherein the latency is modeled using a random variable with known distribution.

3. A method as described in claim 1, wherein the latency is modeled using the following expression:

L=U_{[0,1Hardware]}+U_[0,1Bus]+f_{INPUT STACK}+U_{[0,1GRAPHICS]}+f_SCREEN

where U_{[0,1Hardware]} stands for uniform distribution of hardware latency in range [0,1_Hardware], U_[0,1Bus] stands for uniform distribution of bus latency in range [0,1_Bus], U_{[0,1GRAPHICS]} stands for uniform distribution of graphics latency in range [0,1_GRAPHICS], f_{INPUT STACK} stands for a fixed parameter describing input stack latency, and f_SCREEN stands for a fixed parameter describing screen latency.

4. A method as described in claim 3, wherein U_{[0,1Hardware]} describes a scanning rate of the touchscreen device and U_[0,1Bus] describes latency distribution of a USB connection.

5. A method as described in claim 1, wherein the obtaining of the data includes:

placing a conductor that is disposed proximal to the touchscreen device in a grounded state;

receiving a report from the touchscreen device indicating a point in time at which the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the grounded state.

6. A method as described in claim 5, wherein the obtaining of the data includes:

placing the conductor that is disposed proximal to the touchscreen device in an ungrounded state;

receiving a report from the touchscreen device indicating a point in time at which a lack of the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the lack of the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the ungrounded state.

7. A method as described in claim 5, further comprising synchronizing a clock on the one or more computing devices that is utilized to indicate the point in time at which the conductor was placed in the grounded state with a clock of the touchscreen device that is utilized to indicate the point in time at which the touch input was detected by the touchscreen device.

8. A method as described in claim 5, wherein the placing is performed using an electrical switch driven by the one or more computing devices.

9. A method as described in claim 6, wherein the placing of the conductor in the grounded state emulates a touch by a user and further comprising placing the conductor in an ungrounded state while the conductor is still disposed proximal to the digitizer to emulate a lack of the touch input on the computing device.

10. A computing device comprising:

One or more modules implemented at least partially in hardware, the one or more modules configured to perform operations comprising;

modeling latency of a touchscreen device using parameterized statistics by;

obtaining data describing end-to-end latency measurements of the touchscreen device to recognize a touch input; and

fitting the data to parametric distributions.

11. A computing device as described in claim 10, wherein the latency is modeled using a random variable with known distribution.

12. A computing device as described in claim 10, wherein the latency is modeled using the following expression:

L=U_{[0,1Hardware]}+U_[0,1Bus]+f_{INPUT STACK}+U_{[0,1GRAPHICS]}+f_SCREEN

where U_{[0,1Hardware]} stands for uniform distribution of hardware latency in range [0,1_Hardware], U_[0,1Bus] stands for uniform distribution of bus latency in range [0,1_Bus], U_{[0,1GRAPHICS]} stands for uniform distribution of graphics latency in range [0,1_GRAPHICS], f_{INPUT STACK} stands for a fixed parameter describing input stack latency, and f_SCREEN stands for a fixed parameter describing screen latency.

13. A computing device as described in claim 12, wherein U_{[0,1Hardware]} describes a scanning rate of the touchscreen device and U_[0,1Bus] describes latency distribution of a USB connection.

14. A computing device as described in claim 10, wherein the obtaining of the data includes:

placing a conductor that is disposed proximal to the touchscreen device in a grounded state;

receiving a report from the touchscreen device indicating a point in time at which the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the grounded state.

15. A computing device as described in claim 14, wherein the obtaining of the data includes:

placing the conductor that is disposed proximal to the touchscreen device in an ungrounded state;

receiving a report from the touchscreen device indicating a point in time at which a lack of the touch input was detected by the touchscreen device; and

computing the time delay by comparing the point in time at which the lack of the touch input was detected by the touchscreen device with a point in time at which the conductor was placed in the ungrounded state.

16. A computing device as described in claim 14, further comprising a clock and the one or more operations include synchronizing the clock to indicate the point in time at which the conductor was placed in the grounded state with a clock of the touchscreen device that is utilized to indicate the point in time at which the touch input was detected by the touchscreen device.

17. A computing device as described in claim 14, wherein the placing is performed using an electrical switch driven by the computing device.

18. A computing device as described in claim 15, wherein the placing of the conductor in the grounded state emulates a touch by a user and further comprising placing the conductor in an ungrounded state while the conductor is still disposed proximal to the digitizer to emulate a lack of the touch input on the computing device.

19. A method comprising:

obtaining data, by one or more computing devices, describing end-to-end latency measurements of a touchscreen device to recognize a touch input;

fitting the data to parametric distributions by the one or more computing devices; and

modeling latency of the touchscreen device using parameterized statistics by the one or more computing devices.

20. A method as described in claim 19, wherein the latency is modeled using a random variable with known distribution.