Measurement of eccentricity and twist in spun and plied yarns
Warren J. Jasper, Melih Günay, Minyoung Suh · Journal of the Textile Institute · 2005
The shape of yarn cross-sections can best be approximated as ellipses. This approximation requires the estimation of the major and minor axes and the orientation of the major axes. The diameters of several yarns were measured both circumferentially as well as along the length of the yarn, and the eccentricity was found to be normally distributed. In addition, the direction of the major axes rotated periodically with the twist of the yarn. This allows one to estimate the twist of the yarn indirectly from optical diameter measurements.