Patent ID: 9569054
Date: 2017-02-14
CPC Classifications: G06F,H03K

Claim:
1. A method for operating a touch screen having at least one first electrode and at least one second electrode, each said at least one first electrode intersecting said at least one second electrode, wherein each intersection of said at least one first electrode and said at least one second electrode defines a touch detection node, the method comprising: selectively exciting each said at least one first electrode and thereby selectively generating an electric field about ones of said touch detection nodes corresponding to each said at least one first electrode; periodically determining the capacitance about each of said touch detection nodes; transforming a rolling sample of said capacitance data for each said node from the time domain to the sequency domain using a Walsh-Hadamard Transform, said transformation yielding data in at least a sequency bin determining for each said node, with all of said nodes in an untouched state and no stimulus proximate said touch screen, a reference value in said sequency bin determining for each said node a current value in said sequency bin determining for each said node a delta value by subtracting said current sequency bin analyzing the data in at least one of the sequency bins resulting from the transformation; and entering said delta values into a matrix; applying a two-dimensional centroiding technique to said delta values in said matrix; and determining a touch location with respect to one of an x coordinate and a y coordinate of said touch screen.