Instrumental Evaluation of Fabric Pilling

Image analysis has been widely accepted as an objective method for evaluating fabric appearance, This paper presents the development of an image-analysis method that aims at characterizing and rating fabric-pilling appearance. The procedures involved in using the fast Fourier transform (FFT) and other techniques to correct image defects, such as non-uniform background and low contrast, are demonstrated. Examples are given. A novel approach that splits a fabric image into periodic and non-periodic structures is explained. A template-matching technique used for extracting pills from the non-periodic image is presented. Pill properties are characterized by density, size, and contrast, and measurements on the ASTM photographic standards are used to build the empirical grading equations of fabric-pilling.