Browsing by Author "Moon W. Suh, Committee Co-Chair"

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    Characterization and Quantification of Woven Fabric Irregularities using 2-D Anisotropy Measures
    (2006-08-16) Gunay, Melih; Russell E. Gorga, Committee Member; Behnam Pourdeyhimi, Committee Member; Hien T. Tran, Committee Member; Moon W. Suh, Committee Co-Chair; Warren J. Jasper, Committee Co-Chair
    It is a well known fact that the quality of a fabric is tied to the non-uniformity of fabric properties. Although methods have been suggested to measure certain physical properties of fabrics (mass, handle, strength, comfort, permeability), there has been no single method that is industrially accepted to characterize and quantify distribution of some of these fabric properties or non-uniformities. Therefore, the purpose of this research was to investigate and suggest a new method to fill this need. During this research, data about fabric properties were obtained either directly from images of fabric appearances or indirectly from on-line measurements of yarn diameters. The yarn diameters captured through a line-scan camera were mapped into a 2-D fabric matrix by assigning each point of the yarn to a specific location (x, y) within the 2-D fabric matrix. The gray-scale image of a 2-D fabric matrix was called a virtual fabric and provided the basic information on the uniformity of the fabric property. Variance-area curves were developed to characterize and quantify non-uniformity of actual and virtual fabrics in two dimensions. Certain irregularity features such as vertical and horizontal streaks and random cloudiness produced variance-area curves that are dependent on the shape of the unit area. Thus the difference between these curves became a new way to measure isotropy features of fabric properties. Theoretical relationships between yarns and their virtual fabrics were derived using only the internal correlation information of the given underlying yarns
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    Development of Fabric Image Models and Invariance Property of Variance-Area Curve Within Fabric
    (2002-08-22) Han, Dong; Larry K. Norris, Committee Member; Warren J. Jasper, Committee Co-Chair; Moon W. Suh, Committee Co-Chair
    This thesis is concerned with the development of two prediction models for fabric quality, 2-D and 3-D images for visualization of fabric qualities, and the application of variance-area curves in fabric quality rating. Two types of variance-area curves, CV(A) curve and CB(A) curve, are introduced. They together provide a new way to judge the fabric quality quantitatively in its dependence on the measured area. An invariance property of the variance-area curves within a fabric was also investigated by using fabric prediction models and measured yarn data. Based on two different ways in which weft yarns are mapped onto a fabric, two models are developed by simulating the fabric using measured yarn data and, subsequently, 2-D macro and 3-D micro fabric imaging methods were developed. Application of variance-area curves to woven fabrics and its invariance property were also studied. These are done by using MATLAB® programs. The actual yarn data were captured by an advanced yarn measurement system incorporated by a CTT (Constant Tension Transport) unit, a 12 bit CCD line scan camera, and a program written in C, called "camera1", running on a Linux Operating System platform.