Image-analysis Techniques Part II: The Measurement of Fibre Orientation in Nonwoven Fabrics

Image-processing techniques for measuring the fibre-orientation distribution in a nonwoven fabric are described. The digitised image of the surface of a fabric is progressively simplified by a line operator and edge-smoothing and thinning operations to produce an image in which fibres are represented by curves of one pixel in thickness. The fibre-orientation distribution of a fabric is then obtained by tracing and measuring the length and orientation of these curves. The image-analysis method for automatically measuring the fihre-orientation distribution is validated by manual measurements. A trigonometric function is found to be an appropriate model for the fibre-orientation distribution in nonwoven webs.