Measurement of yarn density in woven fabrics using fringe projection moiré techniques

Fringe projection Moiré, a novel, accurate and fast technique with high repeatability, has been developed in order to measure the yarn density in woven fabrics. In the experimental set-up, collimated laser beams illuminate a Ronchi grating to be projected on a fabric. In case the density of projected lines and fabric becomes the same, the desired moiré pattern is observed on the fabric. As a result, the measurement of the distance between grating and fabric can guide us to find out fabric yarn density by using simple equations. In this regard, twenty five groups of shirting woven fabrics consisting of five weave structures and five different weft densities have been tested. The results show that there is a high correlation (R2 =0.9932) between the data obtained from the new and the conventional methods