Baseline capacitance calibration

摘要

An embodiment of the invention provides a method of creating a statistical model of a baseline capacitance CP of a capacitive sensor located on a capacitive-touch screen. A sensed capacitance CS of a capacitive sensor is measured during a particular state of the electronic device that includes the capacitive-touch screen. When physical contact is not made with the capacitive sensor, the sensed capacitance CS is stored as a baseline capacitance CP. The baseline capacitance CP is then used to create the statistical model for that particular state of the electronic device. When physical contact is made with the capacitive sensor, the value of the baseline capacitance CP of the capacitive sensor is subtracted from the value of the sensed capacitance CS and the result, CF=(CS−CP), is sent to a touch detection circuit.

主权项

1. A non-transitory machine-implemented method of determining a statistical model of a baseline capacitance CP comprising:
measuring a sensed capacitance CS of a capacitive sensor wherein the capacitive sensor is located on a capacitive-touch screen; wherein the capacitive touch screen is located on an electronic device; determining the state of the electronic device; storing the value of the sensed capacitance CS as a baseline capacitance CP based on the state of the electronic device when physical contact is not made with the capacitive sensor; repeating the previous steps; wherein the statistical model for the baseline capacitance Cp is a Gaussian mixture model.