Methods and apparatus for distinguishing between touch system manipulators

1. A user interface method comprising:

determining a signal profile associated with the use of a manipulator with a touch sensor component, the signal profile corresponding to a plurality of signal levels along a surface of the touch sensor component;

calculating a geometrical attribute of that portion of the signal profile having a value that exceeds a threshold signal value; and

determining a type of the manipulator based on the calculated geometrical attribute;

wherein calculating the geometrical attribute includes calculating a first cross-sectional area of the signal profile at a first threshold signal value, and calculating a second cross-sectional area of the signal profile at a second threshold signal value; and

wherein determining the type of the manipulator includes determining that the type of the manipulator is a first type when the first cross-sectional area is substantially equal to a first threshold cross-sectional area, and determining that the type of the manipulator is a second type when the second cross-sectional area is substantially equal to a second threshold cross-sectional area.

2. The user interface method of claim 1 , wherein the geometric attribute is selected from the group consisting of perimeter shape and planar area.

3. The user interface method of claim 1 , further including selecting an input mode from a plurality of input modes based on the type of the manipulator.

4. The user interface method of claim 3 , further including selecting a default mode from the plurality of input modes after a predetermined period of inactivity of the touch sensor component.

5. The user interface method of claim 1 , further including selecting a first input mode when the manipulator is the first type, and selecting a second input mode when the manipulator is the second type.

6. The user interface method of claim 5 , further including reporting a plurality of touch system events using the selected input mode until the cross-sectional area of the signal profile at a threshold signal value is not substantially equal to the threshold cross-sectional area corresponding to the selected input mode.

7. The user interface method of claim 5 , wherein the first type corresponds to a human finger, and the second type corresponds to a stylus.

8. The user interface method of claim 7 , wherein the first threshold signal value is greater than the second threshold signal value.

9. The user interface method of claim 1 , wherein determining the signal profile includes receiving a signal profile associated with a capacitive touch sensor component.

10. A touch system comprising:

a touch sensor component; and

a processor configured to receive a sensor signal from the touch sensor component;

wherein the processor includes a touch detection module configured to determine a signal profile associated with the sensor signal, a signature computation module which is configured to calculate an attribute of the signal profile at a threshold signal value, and a manipulator determination module, which is configured to determine a type of the manipulator based on the computed attribute;

wherein the calculated attribute is a cross-sectional area, and the signal computation module of the processor is further configured to:

determine a first cross-sectional area of the signal profile at a first threshold signal value, and calculate a second cross-sectional area of the signal profile at a second threshold signal value;

determine that the type of the manipulator is a first type when the first cross-sectional area is substantially equal to a first threshold cross-sectional; and

determine that the type of the manipulator is a second type when the second cross-sectional area is substantially equal to a second threshold cross-sectional area.

11. The touch system of claim 10 , wherein the processor includes a mode selection module configured to select one of a plurality of input detection modes based upon the type of the manipulator.

12. The touch system of claim 11 , wherein the mode selection module of the processor is further configured to select a default mode from the plurality of input modes after a predetermined period of inactivity of the touch sensor component.

13. The touch system of claim 10 , wherein the mode selection module of the processor is further configured to select a first input mode when the manipulator is the first type, and select a second input mode when the manipulator is the second type.

14. The touch system of claim 13 , wherein the touch detection module of the processor is further configured to report a plurality of touch system events using the selected input mode until the cross-sectional area of the signal profile at a threshold signal value is not substantially equal to the threshold cross-sectional area corresponding to the selected input mode.

15. The touch system of claim 13 , wherein the processor further includes a gain controller configured to scale a gain associated with the touch sensor component based on the selected mode.

16. The touch system of claim 13 , wherein the first type corresponds to a human finger, and the second type corresponds to a stylus.

17. The touch system of claim 10 , wherein one or more of the touch detection module, the signature computation module, and the manipulator determination module includes one or more sets of stored instructions for execution by a microprocessor.

18. A wireless communication device including a touch system, the touch system comprising:

a touch sensor component for detecting an interaction with a touch sensor surface and producing a sensor signal associated therewith; and

a processor configured to receive the sensor signal from the touch sensor component;

wherein the processor includes a touch detection module configured to determine a signal profile associated with the sensor signal, a cross sectional area computation module configured to calculate a geometrical attribute of the signal profile; and a manipulator determination module configured to determine a type of the manipulator based on the computed geometrical attribute;

wherein the computed geometrical attribute is a cross-sectional area, and the processor is further configured to:

determine a first cross-sectional area of the signal profile at a first threshold signal value, and calculate a second cross-sectional area of the signal profile at a second threshold signal value;

determine that the type of the manipulator is a first type when the first cross-sectional area is substantially equal to a first threshold cross-sectional; and

determine that the type of the manipulator is a second type when the second cross-sectional area is substantially equal to a second threshold cross-sectional area.