METHOD AND APPARATUS FOR DETERMINING SHEET POSITION DURING PRODUCTION AND HANDLING

摘要

A method for determining a position of a selected area of a sheet of material relative to a reference plane includes launching a first incident light beam at the selected area of the sheet of material such that the first incident light beam strikes the selected area at a first position and a first angle, thereby producing a first reflected light beam. A second incident light beam is launched at the selected area of the sheet of material such that the second incident light beam strikes the selected area at a second position and a second angle, thereby producing a second reflected light beam. The second position and second angle are different from the first position and first angle, respectively. The first reflected light beam and the second reflected light beam are intercepted at the reference plane. Information related to positions at which the reflected light beams were intercepted and angles at which the incident light beams were launched were received and correlated to the position of the selected area relative to the reference plane.