Method and apparatus for accurate coordinate calculation of objects in touch applications
View Patent ↗Systems and methods and techniques are disclosed for determining the position and size of an object touching a touch-sensitive display. One embodiment may comprise a set of reference templates—where each reference template is a model and/or data associated with a reference object of a given size. The reference templates may be determined on a priori basis—possibly created during a training phase for the touch display system. The training phase may be performed by stepping an object across a touch display and noting its actuation signal—while the modeling step may be performed by calculating actuation signals based on a model of objects of a given size. With an actual object, its position and size may be determined, calculated and/or estimated by solving a set of inverse finger response functions—e.g., as a set of over-determined linear equations.
1. A method for determining the position of an object on a touch sensitive display, the method comprising:
receiving a set of reference templates, each reference template comprising data associated with an actuation signal initiated by a reference object touching the touch sensitive display;
receiving a first actuation signal, the first actuation signal associated with a touch produced by a first object upon the touch sensitive display;
determining whether the first actuation signal meets a desired local maximum signal value;
if the first actuation signal meets a desired local maximum signal value, determining a set of boundary points substantially near the first actuation signal;
receiving sensor data from the set of boundary points; and
calculating a position of the first object; and
wherein calculating the position further comprises computing a set of inverse functions from the set of boundary points, the set of inverse functions comprising a set of inverse finger response functions.
2. The method of claim 1 wherein the method further comprises:
creating the set of reference templates from a priori information associated with the reference object touching the touch sensitive display.
3. The method of claim 2 wherein creating the set of reference templates from a priori information associated with the reference object further comprises:
performing a training phase, wherein the training phase comprises a set of data from a given reference object, the given reference object comprising an associated size; and
further wherein the training phase comprises receiving actuation data from the given reference object touching the touch-sensitive display at a set of coordinate points.
4. The method of claim 2 wherein creating the set of reference templates from a priori information associated with the reference object touching the touch sensitive display further comprises creating the set of reference templates from a set of modeling calculations, each modeling calculation comprises a function of size of reference object.
5. The method of claim 1 wherein determining whether the first actuation signal meets a desired local maximum value further comprises determining whether the actuation signal is above a noise threshold.
6. The method of claim 1 wherein determining the set of boundary points substantially near the first actuation signal further comprises determining a set of border cells substantially surrounding a set of center cells, the center cells sending actuation signals associated with the first object touching the touch display, wherein the touch display comprises a capacitive touch display.
7. The method of claim 6 wherein calculating the position of the first object further comprises:
receiving sensor data from the set of border cells; and
computing a set of inverse functions from the border cells, the set of inverse functions comprising a set of inverse finger response functions.
8. The method of claim 6 wherein calculating the position of the first object further comprises solving a set of over-determined system of linear equations.
9. The method of claim 8 wherein calculating the position of the first object further comprises calculating a size of the first object comprising solving a set of over-determined system of linear equations.
10. A touch display system, comprising:
a touch-sensitive display; the touch-sensitive display comprising a set of sensor cells, each sensor cell capable of producing actuation signals when an object substantially touches the sensor cell;
a controller, the controller capable of receiving the actuation signals from the touch sensitive display; and
the controller further comprises a processor, the processor capable of executing computer readable instructions for determining a position of the object, the object producing an actuation signal upon a touch sensitive display, the method comprising:
receiving a set of reference templates, each reference template comprising data associated with an actuation signal initiated by a reference object touching the touch sensitive display;
receiving a first actuation signal, the first actuation signal associated with a touch produced by a first object upon the touch sensitive display;
determining whether the first actuation signal meets a desired local maximum signal value;
if the first actuation signal meets a desired local maximum signal value, determining a set of boundary points substantially near the first actuation signal;
receiving sensor data from the set of boundary cells; and
calculating a position of the first object; and
wherein calculating the position further comprises computing a set of inverse functions from the boundary point, the set of inverse functions comprising a set of inverse finger response functions.
11. The touch display system of claim 10 wherein the computer readable instructions further comprises:
creating a set of reference templates from a priori information associated with a reference object touching the touch sensitive display.
12. The touch display system of claim 11 wherein the computer readable instructions further comprises:
performing a training phase, wherein the training phase comprises a set of data from a given reference object, the given reference object comprising an associated size; and
further wherein the training phase comprises receiving actuation data from the given reference object touching the touch-sensitive display at a set of coordinate points.
13. The touch display system of claim 11 wherein the computer readable instructions further comprises:
creating a set of reference templates from a set of modeling calculations, each modeling calculation comprises a function of size of reference object.
14. The touch display system of claim 11 wherein the computer readable instructions further comprises:
determining a set of border cells substantially surrounding a set of center cells, the center cells sending actuation signals associated with the first object touching the touch display, wherein the touch display comprises a capacitive touch-sensitive display.
15. The touch display system of claim 14 wherein the computer readable instructions further comprises:
receiving sensor data from the set of border cells;
computing a set of inverse functions from the border cells, the set of inverse functions comprising a set of inverse finger response functions; and
calculating the position of the first object from the set of inverse functions.
16. A method for determining the position of an object on a touch sensitive display, the method comprising:
receiving a set of reference templates, each reference template comprising data associated with an actuation signal initiated by a reference object touching the touch sensitive display and each reference object comprising a reference size;
receiving a first actuation signal, the first actuation signal associated with a touch produced by a first object at a position upon the touch sensitive display, the first object comprising a size;
determining whether the first actuation signal meets a desired local maximum signal value;
if the first actuation signal meets the desired local maximum signal value, determining a set of boundary points substantially near the first actuation signal;
receiving sensor data from the set of boundary points;
computing a set of inverse functions from the boundary points cells, the set of inverse functions comprising a set of inverse finger response functions; and
calculating the position of the first object from the set of inverse functions.
17. The method of claim 16 wherein the method further comprises:
creating a set of reference templates from a priori information associated with a reference object touching the touch sensitive display.
18. The method of claim 17 wherein the method further comprises:
performing a training phase, wherein the training phase comprises a set of data from a given reference object, the given reference object comprising an associated size; and
further wherein the training phase comprises receiving actuation data from the given reference object touching the touch-sensitive display at a set of coordinate points.
19. The method of claim 17 wherein the method further comprises:
creating a set of reference templates from a set of modeling calculations, each modeling calculation comprises a function of size of reference object.
20. The method of claim 11 wherein the method further comprises:
determining a set of border cells substantially surrounding a set of center cells, the center cells sending actuation signals associated with the first object touching the touch display;
receiving sensor data from the set of border cells;
computing a set of inverse functions from the border cells, the set of inverse functions comprising a set of inverse finger response functions; and
calculating the position of the first object from the set of inverse functions.