System and method for determining object information using an estimated rigid motion response

A touch-screen user interface device comprising:

• an input surface contactable by objects in a sensing region;
• a display screen underlying the input surface, wherein the display screen comprises a conductor configured for use in displaying images on the display screen,
• at least one sensing electrode proximate to the conductor and located between the input surface and the display screen, the at least one sensing electrode configured to capacitively couple with the conductor and objects in the sensing region;
• and
• a processing system communicatively coupled to the at least one sensing electrode,
• the processing system configured to:
• obtain a set of sensor values using the at least one sensing electrode;
• determine an estimated rigid motion response associated with a substantially rigid motion of the at least one sensing electrode relative to the conductor using the set of sensor values, the substantially rigid motion caused by force applied by at least one object to the input surface, wherein the estimated rigid motion response at least partially accounts for effects of capacitive coupling between the at least one sensor electrode and the at least one object;
• and
• determine a force estimate for the force applied by the at least one object in contact with the input surface using the estimated rigid motion response.

A method for responding to user input provided to a sensor device having at least one sensing electrode, wherein conductive material in the at least one sensing electrode is configured to capacitively couple to objects in a sensing region, the method comprising:

• obtaining a set of sensor values using the conductive material;
• determining an estimated rigid motion response associated with a substantially rigid motion of the at least one sensing electrode using the set of sensor values, the substantially rigid motion caused by a force applied by an input object to the sensor device, wherein the estimated rigid motion response at least partially accounts for effects of capacitive coupling between the at least one sensor electrode and the input object;
• determining object information about the input object using the estimated rigid motion response;
• and
• generating an output indicative of the object information.

A processing system for a capacitive input device, the processing system comprising:

• a data acquisition module configured to acquire a set of sensor values using at least one sensing element of the input device, the at least one sensing element configured to capacitively sense input near the sensing element;
• and
• a determiner module configured to:
• determine an estimated rigid motion response associated with a substantially rigid motion of the at least one sensing element using the set of sensor values, the substantially rigid motion caused by a force applied by an object to the input device near the sensing element, wherein the estimated rigid motion response at least partially accounts for effects of capacitive coupling with the object;
• and
• determine object information about the object using the estimated rigid motion response.