Position determination techniques in resistive touch screen applications

A method for determining estimated locations for a dual touch operation performed on a four-wire resistive touch screen, the method comprising:

• capturing signals from pairs of electrodes of first and second resistive sheets of the resistive touch screen during the dual touch operation;
• estimating segment resistances for the first and second resistive sheets of the resistive touch screen;
• calculating estimated signals for the first and second resistive sheets according to a multi-segment resistor model populated by the estimated segment resistances;
• comparing the estimated signals to the captured signals and determining an error value therefrom;
• and
• if the error value is within a predetermined range, estimating X-Y coordinates representing locations of the dual touch operation from the estimated segment resistances.

An apparatus for determining estimated locations for a dual touch operation performed on a four-wire resistive touch screen, the apparatus comprising:

• inputs to capture signals from pairs of electrodes of first and second resistive sheets of the resistive touch screen during the dual touch operation;
• and
• a processing unit configured to:
• estimate segment resistances for the first and second resistive sheets of the resistive touch screen;
• calculate estimated signals for the first and second resistive sheets according to a multi-segment resistor model populated by the estimated segment resistances;
• compare the estimated signals to the captured signals and determining an error value therefrom;
• and
• if the error value is within a predetermined range, estimate X-Y coordinates representing locations of the dual touch operation from the estimated segment resistances.

An apparatus for determining estimated locations for a dual touch operation performed on a four-wire resistive touch screen, the apparatus comprising:

• means for capturing signals from pairs of electrodes of first and second resistive sheets of the resistive touch screen during the dual touch operation;
• and
• means for estimating segment resistances for the first and second resistive sheets of the resistive touch screen;
• means for calculating estimated signals for the first and second resistive sheets according to a multi-segment resistor model populated by the estimated segment resistances;
• means for comparing the estimated signals to the captured signals and determining an error value therefrom;
• and
• means for estimating X-Y coordinates representing locations of the dual touch operation from the estimated segment resistances if the error value is within a predetermined range.