Systems and methods of improved water detection on a touch-sensitive display using directional scanning techniques

1. A method, comprising:

at a touch-sensitive device having one or more processors and a touch-sensitive array that includes a plurality of sensor electrodes:

performing a plurality of scans of the touch-sensitive array using at least two different scan patterns, wherein the plurality of scans captures response data for at least a subset of the plurality of sensor electrodes;

determining a signal direction for each sensor electrode in the subset using the response data, wherein the signal direction for each sensor electrode indicates a relative location of a sensor electrode in the subset most responsible for creation of the signal direction;

identifying one or more touch zones, each comprising a group of sensor electrodes with signal directions that point towards a peak electrode response included in the group, wherein the peak electrode response indicates a location of a candidate touch object on the touch-sensitive array; and

for each identified touch zone:

contributing electrode responses from the group of sensor electrodes in the touch zone to the peak electrode response for the touch zone, and

reporting a touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone satisfies a predefined response threshold.

2. The method of claim 1 , further comprising, at the touch-sensitive device, for each identified touch zone, identifying a non-touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone does not satisfy the predefined response threshold.

3. The method of claim 1 , further comprising, at the touch-sensitive device, for each identified touch zone, determining a shape of the touch zone,

wherein reporting the touch object is further performed in accordance with a determination that the shape of the touch zone satisfies a shape criterion.

4. The method of claim 3 , wherein the shape of the touch zone is associated with a drop, puddle, spray, rivulet, trail, or condensation of water.

5. The method of claim 1 , wherein determining the signal direction for each sensor electrode in the subset comprises:

determining a first axis signal direction for each sensor electrode in the subset;

determining a second axis signal direction for each sensor electrode in the subset;

determining whether the first axis signal direction for each sensor electrode in the subset satisfies a first direction threshold; and

determining whether the second axis signal direction for each sensor electrode in the subset satisfies a second direction threshold.

6. The method of claim 5 , wherein determining the signal direction for each sensor electrode in the subset further comprises:

combining the first axis signal direction with the second axis signal direction.

7. The method of claim 1 , wherein the signal direction is a cardinal direction or a primary inter-cardinal direction.

8. The method of claim 1 , further comprising, at the touch-sensitive device, storing the response data captured from the plurality of scans.

9. The method of claim 1 , wherein identifying the one or more touch zones comprises determining that multiple peak electrode responses are related to the same touch object by:

identifying a first group of sensor electrodes having signal directions that point towards a first peak electrode response included in the first group; and

identifying a second group of sensor electrodes having signal directions that point towards a second peak electrode response included in the second group, wherein:

the first and second peak electrode responses are adjacent to one another, and

the signal directions for the first group of sensor electrodes mirror the signal directions for the second group of sensor electrodes.

10. The method of claim 1 , wherein identifying the one or more touch zones comprises determining that one or more electrode responses in the subset are related to a non-touch object by:

identifying a first group of sensor electrodes having signal directions that point in a first direction; and

identifying a second group of sensor electrodes having signal directions that point in a second direction, wherein:

the second direction is opposite to the first direction, and

the first and second groups of sensor electrodes are adjacent to one another.

11. The method of claim 1 , wherein identifying the one or more touch zones comprises determining that multiple peak electrode responses are related to different touch objects by:

identifying a first group of sensor electrodes having signal directions that point towards a first peak electrode response included in the first group; and

identifying a second group of sensor electrodes having signal directions that point towards a second peak electrode response included in the second group, wherein the first and second peaks are adjacent to and separated by at least one sensor electrode.

12. The method of claim 1 , further comprising, at the touch-sensitive device, performing a plurality of additional scans of the touch-sensitive array using the at least two different scan patterns in response to identifying the one or more touch zones,

wherein reporting the touch object for each identified touch zone is further performed in accordance with a determination that the same touch zone is identified by the plurality of additional scans.

13. The method of claim 1 , wherein:

one of the identified touch zones is positioned along an edge of the touch-sensitive array and

the method further comprises, at the touch-sensitive device, for the touch zone positioned along the edge of the touch-sensitive array:

determining a number of sensor electrodes in the touch zone that are adjacent to the edge of the touch-sensitive array; and

reporting a size of the touch object based at least in part on: (i) a value of the peak electrode response for the touch zone, and (ii) the number of sensor electrodes in the touch zone that are adjacent to the edge of the touch-sensitive array.

14. A touch-sensitive device, comprising:

a touch-sensitive array that includes a plurality of sensor electrodes;

one or more processors; and

memory storing one or more programs, the one or more programs including instructions, which when executed by the one or more processors cause the touch-sensitive device to:

perform a plurality of scans of the touch-sensitive array using at least two different scan patterns, wherein the plurality of scans captures response data for at least a subset of the plurality of sensor electrodes;

determine a signal direction for each sensor electrode in the subset using the response data, wherein the signal direction for each sensor electrode indicates a relative location of a sensor electrode in the subset most responsible for creation of the signal direction;

identify one or more touch zones, each comprising a group of sensor electrodes with signal directions that point towards a peak electrode response included in the group, wherein the peak electrode response indicates a location of a candidate touch object on the touch-sensitive array; and

for each identified touch zone:

contribute electrode responses from the group of sensor electrodes in the touch zone to the peak electrode response for the touch zone, and

report a touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone satisfies a predefined response threshold.

15. The touch-sensitive device of claim 14 , wherein the one or more programs further include instructions, which when executed by the one or more processors cause the touch-sensitive device to:

for each identified touch zone, identify a non-touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone does not satisfy the predefined response threshold.

16. The touch-sensitive device of claim 14 , wherein the one or more programs further include instructions, which when executed by the one or more processors cause the touch-sensitive device to:

for each identified touch zone, determine a shape of the touch zone,

wherein reporting the touch object is further performed in accordance with a determination that the shape of the touch zone satisfies a shape criterion.

17. The touch-sensitive device of claim 16 , wherein the shape of the touch zone is associated with a drop, puddle, spray, rivulet, trail, or condensation of water.

18. A non-transitory computer-readable storage medium, storing one or more programs configured for execution by one or more processors of a touch-sensitive device having a touch-sensitive array that includes a plurality of sensor electrodes, the one or more programs including instructions for:

performing a plurality of scans of the touch-sensitive array using at least two different scan patterns, wherein the plurality of scans captures response data for at least a subset of the plurality of sensor electrodes;

determining a signal direction for each sensor electrode in the subset using the response data, wherein the signal direction for each sensor electrode indicates a relative location of a sensor electrode in the subset most responsible for creation of the signal direction;

identifying one or more touch zones, each comprising a group of sensor electrodes with signal directions that point towards a peak electrode response included in the group, wherein the peak electrode response indicates a location of a candidate touch object on the touch-sensitive array; and

for each identified touch zone:

contributing electrode responses from the group of sensor electrodes in the touch zone to the peak electrode response for the touch zone, and

reporting a touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone satisfies a predefined response threshold.

19. The non-transitory computer-readable storage medium of claim 18 , wherein the one or more programs further include instructions for:

for each identified touch zone, identifying a non-touch object at the location associated with the peak electrode response in accordance with a determination that the contributed peak electrode response for the touch zone does not satisfy the predefined response threshold.

20. The non-transitory computer-readable storage medium of claim 18 , wherein the one or more programs further include instructions for:

for each identified touch zone, determining a shape of the touch zone,

wherein reporting the touch object is further performed in accordance with a determination that the shape of the touch zone satisfies a shape criterion.