Abstract: A system of measuring light transmission and/or reflection has a light transmitter(s) and at least one light sensor which are used to generate a defined light environment over a specified light frequency range.

Abstract: A method and apparatus for optically measuring properties of sheets of transparent material which may be moving. The apparatus includes a non-Gaussian line laser beam generator and a linear sensor such as a CCD array which senses the spacing of reflections of the laser beam from surfaces of the material and the strength of the reflections. The width of the line laser beam extends in a direction perpendicular to the direction of the linear sensor. The line laser beam is directed at an angle to the surfaces of the material and surface reflections detected by the sensor are used to detect at least one property of the material, such as surface spacings or the presence and location of a surface coating. The line laser beam reflections will strike the sensor even when the material is not precisely parallel to the sensor.