Determination of Weave Type in Woven Fabric by Digital Image Processing

Abstract

Weave types of commercial woven fabrics were determined by analysing the two-dimensional Fourier transformation patterns of the reflected images. Data collection and data analysis were done by image processing system based on a microcomputer. The relationships between the structural units of weave types and the Fourier power spectra are summarized as follows: (1) structural unit is observed in the unit cell defined by the neighboring two warp yarns and two filling yarns in Fourier space, (2) weave harrness is obtained by counting the number of power spectra inside the unit cell, (3) structural unit is equivalent to the Fourier power spectrum arrangement of the reflected image rotated by 90 degree. A woven fabric made of the cross combination of the warp and filling yarns has a two-dimensional lattice structure. To study the fabric structure, it is useful to observe the periodic arrangement of the surface contours associated with the yam faces or the geometrical intersticies enclosed by neighboring two yams. They have an effect on the optical and mechanical properties of the fabric. In practice, the quality of the woven product is related to the geometrical shape of the lattice structure and their irregularity distribution, and the visual and handling properties are also related to the surface contours of the fabric. The fabric analysis is made to determine the fabric structure. The real time data processing and the automatical method for the detection and discrimination are required in place of the manual measurement. We have mainly studied an optical image evaluation on the periodic arrangement of the fabric structure by observing the optical diffraction pattern. In the previous papers, we have described the detection of fabric defects l'21, the discrimination among fabric defects131, and the local irregularity under uniaxial extension~41 In these above analysis, the two-dimensional arrangement defined by yam intersticies have been investigated. The surface contour pattern is also one of the periodic arrangement defined by the structral unit arrangement, i.e. weave type. The weave type of a woven fabric is constructed by the repetition in space of a structural unit defined by the warp and filling faces. The theoretical studies of the construction for the complete design have been made by several investigators~s-71 Numerical method for constructing the complete weaves has