Patent ID: 6038028
Filing Date: 2000-03-14
Classification: G01B

Abstract:
An optical measurement apparatus for measuring the thickness of fast moving sheet material having opposite surfaces, the optical measurement apparatus having a pair of opposing optical systems, each optical system comprising:a high-power light source, said light source for emitting a light beam toward a sheet material surface, at least a portion of said light beam reflecting off of said sheet material surface;a plurality of photodetectors combined to form a photodetector array, said photodetector array for receiving a reflected portion of said light beam, said reflection imaged as a spot upon said photodetector array;a plurality of current measurement circuits each simultaneously communicating in parallel directly with an individual photodetector; and,a centroid measurement circuit;said plurality of current measurement circuits each simultaneously communicating in parallel an electrical signal to said centroid measurement circuit, said centroid measurement circuit processing the electrical signals in parallel to calculate the centroid of said spot.