A touch screen in the form of a panel is capable of conducting signals and a tomograph including signal flow ports is positioned adjacent the panel with the signal flow ports arrayed around the border of the panel at discrete locations. Signals are introduced into the panel to pass from each discrete border location to a plurality of other discrete border locations for being detected and tomographically processed to determine if any change occurred to signals due to the panel being touched during signal passage through the panel, and therefrom determine any local area on the panel where a change occurred. The tomograph computes and outputs a signal indicative of a panel touch and location, which can be shown on a display.