Patent ID: 8330474

Claim:
A sensor device comprising: a first array of sensing electrodes under a surface and configured to capacitively sense objects in a sensing region; a processing system coupled to the first array of sensing electrodes, the processing system configured to: determine positional information for an object at the surface and in a first portion of the sensing region; and determine positional information for an object away from the surface and in a second portion of the sensing region, wherein the first portion of the sensing region is between the surface and the second portion, by: determining measured values, the measured values comprising a measured value for each electrode in the first array of sensing electrodes; determining first combined values using the measured values for a first subset of electrodes in the first array of sensing electrodes, where the first subset of electrodes includes at least two electrodes in the first array of sensing electrodes; determining second combined values using the measured values for a second subset of electrodes in the first array of sensing electrodes, where the second subset of electrodes includes at least two electrodes in the first array of sensing electrodes; determining difference values using the first combined values and the second combined values, each of the difference values based at least in part on a difference between at least one of the first combined values and at least one of the second combined values; and generating positional information for the object away from surface using the difference values.