Development of a Yarn Evenness Measurement and Hairiness Analysis System

This paper presents an automatic yarn characterization system, based on capacitive sensors for evenness measurement and on optical sensors for hairiness analysis. This approach enables direct yarn mass determination in 1 mm range for evenness, an increase by a factor of eight over the most common commercial solutions (8 mm), and will also enable hairiness measurement up to 1 mm with high accuracy. This system determines all parameters commonly used in textile industry, for different sensitivity values defined by the operator. It also presents new parameters, not measured by commercial equipments (integral deviation rate-IDR, different signal processing techniques to detect error patterns (fast Walsh-Hadamard transform-FWHT) and other adapted parameters (deviation rate-DR, spectrograms (fast Fourier transform-FFT), coefficient of variation-CV, mean deviation-U, number and length of faults)