Determination of valid touches based on force shape

A processing device, comprising:

• a processing core;
• a capacitance sense circuit;
• and
• memory storing one or more programs configured for execution by the processing core, the one or more programs comprising instructions for:
• obtaining a plurality of capacitive sense signals from a plurality of sense electrodes of a capacitive sense array;
• in accordance with the plurality of capacitive sense signals, determining one or more candidate touches on the touch sensing surface;
• determining a matrix of expected force values based on the one or more candidate touches, each expected force value in the matrix of expected force values corresponding to a respective electrode of a plurality of force electrodes;
• obtaining a plurality of force signals from the plurality of force electrodes;
• in accordance with the plurality of force signals, determining a matrix of actual force values caused on the touch sensing surface by the one or more candidate touches, each actual force value in the matrix of actual force values corresponding to a respective electrode of the plurality of force electrodes;
• and
• comparing the matrix of actual force values to the matrix of expected force values to determine a magnitude of force associated with each of the one or more candidate touches, including determining whether each of the one or more candidate touches is a valid touch.

An electronic system, comprising:

• a capacitive sense array coupled to a touch sensing surface, the capacitive sense array including a plurality of sense electrodes;
• a plurality of force electrodes;
• and
• a processing device coupled to the capacitive sense array and the plurality of force electrodes, wherein the processing device is configured to:
• obtain a plurality of capacitive sense signals from the plurality of sense electrodes of the capacitive sense array;
• in accordance with the plurality of capacitive sense signals, determine one or more candidate touches on the touch sensing surface;
• determine a matrix of expected force values based on the one or more candidate touches, each expected force value in the matrix of expected force values corresponding to a respective electrode of the plurality of force electrodes;
• obtain a plurality of force signals from the plurality of force electrodes;
• in accordance with the plurality of force signals, determine a matrix of actual force values caused on the touch sensing surface by the one or more candidate touches, each actual force value in the matrix of actual force values corresponding to a respective electrode of the plurality of force electrodes;
• and
• compare the matrix of actual force values to the matrix of expected force values to determine a magnitude of force associated with each of the one or more candidate touches, including determining whether each of the one or more candidate touches is a valid touch.