Abstract: In this paper, the application of image processing technique for fiber orientation in thicker nonwovens was discussed. First, multi-focal image fusion was employed to capture sharp-focused images in the super depth of field. Secondly, boundary detector was used to extract fibers’ two edges indicating fiber orientation. Finally, fiber segments’ orientation angle was calculated using boundary integral algorithm. Finally, fiber orientation distribution within the range of 0 to 180 degree can be obtained. Results obtained using image fusion was verified by manually depicting fiber orientations in their SEMs. Meanwhile, short-span tensile tests were conducted to study relation between fiber orientation and materials’ mechanical orientation. Experimental results demonstrate that the new method is useful to measure fiber orientation in thicker nonwovens.

Key words: nonwovens, fiber orientation distribution, multi-focal image fusion, boundary curve integral