Patent ID: 6566670
Filing Date: 2003-05-20
Classification: B65H,G01N

Abstract:
A system for guiding a web of moving material the system comprising:a first light source oriented to project light onto a surface of the web of moving material, the first light source being operable to project a plurality of selectable wavelengths of light; a second light source oriented to project light onto the surface of the web of moving material, the second light source being operable to project a plurality of selectable wavelengths of light; a plurality of photodiodes oriented to receive light reflected from the surface of the web of moving material, the plurality of photodiodes being operable to generate a data signal in response to the light received; and a controller operable to generate a control signal in response to the data signal, the control signal comprising an indication of a position of the web of moving material, wherein the first light source and the second light source can be selected to project light in response to a first selection criteria and the first and second light sources do not project light simultaneously, and a wavelength of the projected light can be selected in response to a second selection criteria.