Touch rejection for wet fabric
Touch input processing for touch-sensitive devices can be used to filter unintended contact detected on a touch-sensitive surface. Moist or wet fabrics on the edge of a touch-sensitive surface can be erroneously be detected as touch input and degrade touch performance. In some examples, input paths can be classified as touch paths or non-touch paths (corresponding to wet fabrics). Non-touch paths can be filtered out to avoid unintended input to a touch-sensitive device. Classifying paths can improve touch performance in environments where a wet fabric may come in contact with the edge of the touch-sensitive surface. In some examples, paths can be classified as touch paths or non-touch paths based on characteristics of edge touch nodes. In some examples, paths can be classified as touch paths or non-touch paths based on a determined state.
1. An electronic device comprising:
a touch-sensitive surface; and
one or more processors coupled to the touch-sensitive surface programmed to:
identify a path in touch images, the path comprising one or more input patches corresponding to an object touching or proximate to the touch-sensitive surface;
determine touch image parameters for the touch images corresponding to the path, the touch image parameters including a number of qualifying edge touch nodes, wherein the qualifying edge touch nodes are within a threshold distance from an edge of the touch-sensitive surface;
classify the path as a touch path or a non-touch path based on the determined touch image parameters;
in accordance with classifying the path as a touch path, process the path as touch input; and
in accordance with classifying the path as a non-touch path, forgo processing the path as touch input.
2. The electronic device of claim 1 , wherein the touch image parameters corresponding to the path include a maximum number of qualifying edge touch nodes, a maximum number of qualifying touch nodes, a maximum touch signal, or a minimum gradient.
3. The electronic device of claim 2 , wherein the path is classified as a non-touch path when:
(1) the maximum number of qualifying edge touch nodes is greater than or equal to a threshold number of qualifying edge touch nodes;
(2) the minimum gradient is greater than or equal to a first gradient threshold;
(3) the minimum gradient is less the first gradient threshold, but greater than a second gradient threshold, and the maximum number of qualifying touch nodes is greater than or equal to a first threshold number of qualifying touch nodes; or
(4) the minimum gradient is less the second gradient threshold, the maximum touch signal is less than a threshold signal, and the maximum number of qualifying touch nodes is greater than or equal to second threshold number of qualifying touch nodes.
4. The electronic device of claim 1 , wherein classifying the path occurs upon liftoff of the object corresponding to the path.
5. The electronic device of claim 1 , wherein classifying the path occurs once the path includes a threshold number of input patches.
6. The electronic device of claim 1 , wherein one or more processors are further programmed to:
determine a state from a first state and a second state based on touch image parameters;
wherein classifying the path based on the determined touch image parameters comprises classifying the path based on the state.
7. The electronic device of claim 6 , wherein determining the state comprises:
transitioning from the first state to the second state when a qualifying edge condition is detected for a first threshold period of time; and
transitioning from the second state to the first state when the qualifying edge condition is not detected for a second threshold period of time.
8. The electronic device of claim 6 , wherein determining the state comprises:
determining a respective state for a first region of the touch-sensitive surface based on the touch image parameters for the first region of the touch-sensitive surface and a respective state of a second region of the touch-sensitive surface based on the touch image parameters for the second region of the touch-sensitive surface.
9. The electronic device of claim 8 , wherein classifying the path based on the state comprises:
in accordance with the path being located in the first region of the touch-sensitive surface, classifying the path based on the respective state for the first region of the touch-sensitive surface; and
in accordance with the path being located in the second region of the touch-sensitive surface, classifying the path based on the respective state for the second region of the touch-sensitive surface.
10. The electronic device of claim 8 , wherein classifying the path based on the state comprises:
in accordance with the path being located in the first region of the touch-sensitive surface and within a threshold distance of a first edge of the touch-sensitive surface, classifying the path based on the respective state for the first region of the touch-sensitive surface;
in accordance with the path being located in the second region of the touch-sensitive surface and within the threshold distance of a second edge of the touch-sensitive surface opposite the first edge, classifying the path based on the respective state for the second region of the touch-sensitive surface; and
in accordance with the path being located in the first region of the touch-sensitive surface outside the threshold distance of the first edge or in the second region of the touch-sensitive surface outside the threshold distance of the second edge, classifying the path as the touch path.
11. A method comprising:
identifying a path in touch images, the path comprising one or more input patches corresponding to an object touching or proximate to a touch-sensitive surface;
determining touch image parameters for the touch images corresponding to the path, the touch image parameters including a number of qualifying edge touch nodes, wherein the qualifying edge touch nodes are within a threshold distance from an edge of the touch-sensitive surface;
classifying the path as a touch path or a non-touch path based on the determined touch image parameters;
in accordance with classifying the path as a touch path, processing the path as touch input; and
in accordance with classifying the path as a non-touch path, forgoing processing the path as touch input.
12. The method of claim 11 , wherein the touch image parameters corresponding to the path include a maximum number of qualifying edge touch nodes, a maximum number of qualifying touch nodes, a maximum touch signal, or a minimum gradient.
13. The method of claim 12 , wherein the path is classified as a non-touch path when:
(1) the maximum number of qualifying edge touch nodes is greater than or equal to a threshold number of qualifying edge touch nodes;
(2) the minimum gradient is greater than or equal to a first gradient threshold;
(3) the minimum gradient is less the first gradient threshold, but greater than a second gradient threshold, and the maximum number of qualifying touch nodes is greater than or equal to a first threshold number of qualifying touch nodes; or
(4) the minimum gradient is less the second gradient threshold, the maximum touch signal is less than a threshold signal, and the maximum number of qualifying touch nodes is greater than or equal to second threshold number of qualifying touch nodes.
14. The method of claim 11 , wherein classifying the path occurs upon liftoff of the object corresponding to the path.
15. The method of claim 11 , wherein classifying the path occurs once the path includes a threshold number of input patches.
16. The method of claim 11 , the method further comprising:
determining a state from a first state and a second state based on touch image parameters;
wherein classifying the path based on the determined touch image parameters comprises classifying the path based on the state.
17. The method of claim 16 , wherein determining the state comprises:
transitioning from the first state to the second state when a qualifying edge condition is detected for a first threshold period of time; and
transitioning from the second state to the first state when the qualifying edge condition is not detected for a second threshold period of time.
18. The method of claim 16 , wherein determining the state comprises:
determining a respective state for a first region of the touch-sensitive surface based on the touch image parameters for the first region of the touch-sensitive surface and a respective state of a second region of the touch-sensitive surface based on the touch image parameters for the second region of the touch-sensitive surface.
19. The method of claim 18 , wherein classifying the path based on the state comprises:
in accordance with the path being located in the first region of the touch-sensitive surface, classifying the path based on the respective state for the first region of the touch-sensitive surface; and
in accordance with the path being located in the second region of the touch-sensitive surface, classifying the path based on the respective state for the second region of the touch-sensitive surface.
20. The method of claim 18 , wherein classifying the path based on the state comprises:
in accordance with the path being located in the first region of the touch-sensitive surface and within a threshold distance of a first edge of the touch-sensitive surface, classifying the path based on the respective state for the first region of the touch-sensitive surface;
in accordance with the path being located in the second region of the touch-sensitive surface and within the threshold distance of a second edge of the touch-sensitive surface opposite the first edge, classifying the path based on the respective state for the second region of the touch-sensitive surface; and
in accordance with the path being located in the first region of the touch-sensitive surface outside the threshold distance of the first edge or in the second region of the touch-sensitive surface outside the threshold distance of the second edge, classifying the path as the touch path.
21. A non-transitory computer readable storage medium storing instructions, which when executed by one or more processors, cause the one or more processors to perform a method, the method comprising:
identifying a path in touch images, the path comprising one or more input patches corresponding to an object touching or proximate to a touch-sensitive surface;
determining touch image parameters for the touch images corresponding to the path, the touch image parameters including a number of qualifying edge touch nodes, wherein the qualifying edge touch nodes are within a threshold distance from an edge of the touch-sensitive surface;
classifying the path as a touch path or a non-touch path based on the determined touch image parameters;
in accordance with classifying the path as a touch path, processing the path as touch input; and
in accordance with classifying the path as a non-touch path, forgoing processing the path as touch input.
22. The method of claim 21 , wherein the touch image parameters corresponding to the path include a maximum number of qualifying edge touch nodes, a maximum number of qualifying touch nodes, a maximum touch signal, or a minimum gradient.
23. The non-transitory computer readable storage medium of claim 22 ,
wherein the path is classified as a non-touch path when:
(1) the maximum number of qualifying edge touch nodes is greater than or equal to a threshold number of qualifying edge touch nodes;
(2) the minimum gradient is greater than or equal to a first gradient threshold;
(3) the minimum gradient is less the first gradient threshold, but greater than a second gradient threshold, and the maximum number of qualifying touch nodes is greater than or equal to a first threshold number of qualifying touch nodes; or
(4) the minimum gradient is less the second gradient threshold, the maximum touch signal is less than a threshold signal, and the maximum number of qualifying touch nodes is greater than or equal to second threshold number of qualifying touch nodes.
24. The non-transitory computer readable storage medium of claim 21 , wherein classifying the path occurs upon liftoff of the object corresponding to the path.
25. The non-transitory computer readable storage medium of claim 21 , wherein classifying the path occurs once the path includes a threshold number of input patches.