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 nonuniform 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.