Image Analysis for Evaluating Uniformity in Synthetic Fiber Properties Using Limit Samples

In the manufacturing of synthetic fibers, uniformity of the fiber properties is a critical quality control parameter. Currently, visual assessment by expert inspectors is the predominant method for evaluating the uniformity of synthetic fiber. A quantitative evaluation method using image analysis was investigated to establish a more accurate and efficient approach. As a fundamental step, this study focused on quantifying the evaluation scale of limit samples. The limit sample was a dye-circular plain-knitted fabric comprising five units, each of which was assigned a grade of fiber or yarn quality. The uniformity of synthetic fiber properties, especially the degree of streaky dyeing unevenness observed in dye-circular plain-knitted fabrics, was demonstrated to be expressed using image features. The image features were statistics about the gray-level gradients in the wale direction, obtained by horizontal edge detection on an image with loops removed by low-pass filtering. Furthermore, these image features and grade values representing synthetic fiber uniformity exhibited a linear relationship with a remarkably high coefficient of determination.