Kemira Oyj

Mikko Makinen

Henry Skoog

Jukka-Pekka Raunio

Clayton Campbell

The invention relates to a method and arrangement for detecting free fiber ends in a paper surface. The method comprises illuminating a target sample () surface, which comprises free fiber ends, from at least two directions one at the time, with at least one light source (). Original reflectance images are obtained for the target sample () surface with an imaging device (), and a surface normal is estimated for each image pixel of the original reflectance image. Thus it is possible to reconstruct a reconstructed reflectance image from the estimated surface normals, and to compare the reconstructed reflectance image and the corresponding original reflectance image and to construct a difference image, where the differences represent shadow objects of the free fiber ends in a paper surface.

Method and arrangement for detecting free fibre ends in paper

Methods of characterizing the topography of a surface of a creped material, devices for characterizing surface topography of a creped material, computer systems for characterizing surface topography of a creped material, and the like, are disclosed.

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Espoo, Finland

Mikko Makinen