Y. Gowayed et al., SURFACE INSPECTION OF TEXTILE COMPOSITE-MATERIALS USING IMAGE-ANALYSIS TECHNIQUES, Journal of composites technology & research, 18(1), 1996, pp. 3-14
In this paper, a novel visual quality control technique for production
of textile composite materials is presented. This technique is based
on the idea of automated image processing. The approach starts by acqu
iring images of the surface of a composite product using a combination
of a microscope and a frame grabbing board connected to a computer. I
mage processing is then applied to the acquired images to extract impo
rtant features. In the current study, the features of importance are o
rientation of surface yarns. The image analysis approach is constructe
d taking into consideration the intrinsic characteristics of the acqui
red images. Important image features are enhanced using a Difference o
f Gaussians and a set of directional edge detection kernels. The enhan
ced image is then thresholded using a ''Fixed Percent Setting'' techni
que and converted into binary format. Hough Transform and Bounding Box
approaches are utilized for object (that is, fibers) recognition in t
he binarized image. This approach is carried out on 20 ceramic composi
te parts. The fabric preform was manually placed in all these parts. T
he technique was successful in determining predominate directions orie
ntation of surface yarns in most of the parts. Matrix material in some
areas of these parts were over-grown in the infiltration process. Due
to this phenomena, 6% of the acquired images have no data available a
bout yam's orientation. Consequently, the image analysis approach is u
nsuccessful in obtaining information about yam directions in these are
as.