Evaluating Fibrous Architecture of Nonwovens with Computer-Assisted Microscopy 1

A new computerized imaging, circular polarized light microscopy technique is de veloped to measure the orientation of fibers in images of nonwovens. The system consists of a modified Olympus BX50 polarized microscope, a Sony AVC-D7 video camera, and a Silicon Graphics Indy computer. There are two methods of image seg mentation : Gaussian distribution' based minimum error thresholding and Poisson dis tribution based minimum error thresholding. Segments of fiber midlines are traced with vertical and horizontal scanlines or, alternatively, whole midlines are identified recur sively with the Hilditch technique. The fiber midlines produced with this technique are traversed by a midline traversal algorithm, and the orientation distribution is obtained by least squares line fitting. The accuracy of the technique is evaluated against synthetic images composed of straight lines and sinuous curves. Kupier's statistic is used to evaluate the consistency of the fiber orientation calculations. A statistical analysis of the results shows that the proposed Hilditch connectivity, which preserves skeletoni zation, produces the most accurate results.