A capacitive touch screen display operates by: receiving a plurality of sensed signals indicating variations in mutual capacitance associated with a plurality of cross points formed by a plurality of electrodes; generating capacitance image data associated with the plurality of cross points that includes positive capacitance variation data corresponding to positive variations of the capacitance image data from a nominal value and negative capacitance variation data corresponding to negative variations of the capacitance image data from the nominal value; determining, based on the positive capacitance variation data and the negative capacitance variation data, an upper threshold and a lower threshold; generating compensated capacitance image data, based on the upper threshold and the lower threshold; and processing the compensated capacitance image data to determine a proximal condition of the touch screen display.