| 摘要 |
An image-based technique that measures the orientation of fibers in a moving web of nonwoven material includes the steps of: (a) illuminating essentially simultaneously at least four light spots on one side of the web with at least four plane-polarized incident substantially perpendicular light beams having different polarization characteristics, (b) measuring the dispersion of the excident light spots on the opposite side of the web along at least one linear section which is at a known angle relative to the plane of polarization of the corresponding plane-polarized incident light beam, wherein at least one such linear section lies substantially across the center of the transmitted excident light spot and extends substantially across the width of the transmitted excident light spot, (c) calculating variations in the dispersion of the transmitted excident light spot for the at least four plane-polarized light beams; and (d) estimating the fiber orientation from the variations.
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