Efficient algorithm for accurate touch detection of large touch screen panels

Abstract

Large mutual capacitance touch screen panels (TSP) are susceptible to display and ambient noise. This paper presents a multi-touch detection algorithm using an efficient noise compensation technique for large mutual capacitance TSPs. The algorithm starts with a calibration technique to overcome TSP mutual capacitance variation. It also overcomes the shadow effect of a hand close to TSP and mutual capacitance variation by applying dynamic threshold calculations. Time and space filters are also used to filter out noise. Experimental results are used to determine system parameters for best performance.