Objective Measure of Woven Fabric’s Cover Factor by Image Processing

Abstract

Digital image processing techniques have been applied to perform an automatic method for the objective measure of woven fabric’s cover factor. Based on a frequency domain analysis, digital images of woven fabric samples, obtained with a camera assembled to a microscope, were cropped to enclose the maximum integer number of warp and weft periods and leveled for non-uniform illumination. Posterior thresholding, designed to perform satisfactorily for both high and low cover factor fabric samples, gave rise to the objective value. The method was applied to three different sets of samples manufactured in plain weave, with known yarn numbers and thread counts. Cover factors obtained by this method showed good correlation with those obtained by a set of visual observers and were consistent with woven fabric parameters: yarn numbers (tex) and thread counts (yarns/cm). The procedure could be useful to monitor mean cover factor as well as cover factor variability in fabric batches. It does not require sophisticated equipment and could be straightforwardly implemented in a textile analysis laboratory.