Absorption and Scatter Corrections for Transflectance Measurements in Nonhomogeneous Fiber Samples

Abstract

A new fiber optic sensor was developed to measure the mass of optically thin cotton samples by integrating light transmission and reflectance signals. High speed measurements of cotton strength requires an accurate determination of the specimen mass without use of laborious cut-and-weigh methods. A previous high speed sensor measured changes in visible light transmission which required secondary measurements of fiber fineness to adjust the data for light scattering. Fiber orientation also affected scattering which required a precise control on specimen preparation. The new sensor measures fiber specimen transflectance using near infrared light. Because cellulose (the basic compound in cotton) exhibits strong absorption bands, its concentration can be accurately measured using near infrared absorbance. In this report we show that an integratinq sensor gave the best measurement of cotton fiber mass. Additionally, we demonstrated its accuracy over a wide range of fiber orientations using a novel fiber specimen tension experiment.