Patent ID: 7301164

Claim:
A measuring apparatus comprising: an illumination unit including a source of electromagnetic radiation; fiber optic apparatus including first fiber optic structure comprising a bundle of first optical fibers having first input ends for receiving at least a portion of electromagnetic radiation emitted from said radiation source and first output ends for directing the received radiation to a web of material, and second fiber optic structure comprises a bundle of second optical fibers having second input ends for receiving radiation reflected from said web of material and second output ends for directing said reflected radiation to a sensing apparatus, said first output ends being randomly intermixed with said second input ends and being positioned at an angle of from about 30 degrees to about 60 degrees to said web of material such that said second input ends receive substantially only diffuse electromagnetic radiation reflected from said web of material; and wherein said sensing apparatus comprises a first detector for sensing electromagnetic radiation of a first wavelength band and generating a corresponding first output signal and a second detector for sensing electromagnetic radiation of a second wavelength band and generating a corresponding second output signal indicative of a first property to be measured of said web of material.