Touch screen signal processing with single-point calibration

Abstract

A coordinate detection system can comprise a display screen, a touch surface corresponding the top of the display screen or a material positioned above the screen and defining a touch area, at least one camera outside the touch area and configured to capture an image of space above the touch surface, and a processor executing program code to identify whether an object interferes with the light from the light source projected through the touch surface based on the image captured by the at least one camera. The processor can be configured to carry out a calibration routine utilizing a single touch point in order to determine a plane corresponding to the touch surface by using mirror images of the features adjacent the touch surface, images of the features, and/or based on the touch point and a normal to the reflective plane defined by an image of the object and its mirror image.

Dependencies are inferred from the claim text.