Woven Fabric Analysis by Image Processing. Part II: Computing the Twist Angle

Abstract

We present an efficient and nondestructive way to compute fiber angles and twist angles of yarns using image processing. The pixels over the floats in an image that can portray fiber paths are detected and labeled, then the labeled pixels are connected to a chain-coded curve by tracing the path of individual fibers. Thus, fiber angles are estimated by the trigonometric relationship between the measured rectangular components of the chain-coded curves. The approximate twist angle of a yarn is statistically computed from all the estimated fiber angles with this yarn. Experiments involve plain, twill, and satin fabrics, each with twenty specimens, and the results show good agreement with manual measurements.