Estimation of curl in paper: an industrial application combining shape measurement and least squares modeling
2000 (English)In: Proceedings / International Conference on Trends in Optical Nondestructive Testing: Lugano, Switzerland, May 3-6, 2000 / [ed] Pramod K. Rastogi; D. Inaudi, Lugano: Ecole Polytechnique Fédérale de Lausanne , 2000, 23-33 p.Conference paper (Refereed)
If a sheet of paper is subjected to humidity changes and have structural variations through its thickness such as gradients of fibre orientation, density and filler content, the sheet will curl and hence assume a cylindrical shape. Curl is a quality problem that makes the paper less suitable for printing. We propose a method to measure curl that can be used for automated analysis of the paper quality. The shape of the curled paper is measured from the perspective difference in a stereoscopic camera system, which is viewing an irregular pattern that is projected onto the specimen. The perspective difference is calculated by a correlation algorithm, a technique often referred to as digital speckle photography. The most interesting quality parameters are the magnitude of curl, which is defined as the inverse of the radius of curvature and also the orientation of the curled paper. These parameters are estimated by performing a least squares fit of a cylindrical shape to the three-dimension...
Place, publisher, year, edition, pages
Lugano: Ecole Polytechnique Fédérale de Lausanne , 2000. 23-33 p.
Research subject Scientific Computing
IdentifiersURN: urn:nbn:se:ltu:diva-37386Local ID: b647f550-38b8-11dd-8721-000ea68e967bOAI: oai:DiVA.org:ltu-37386DiVA: diva2:1010884
International Conference on Trends in Optical Nondestructive Testing : 03/05/2000 - 05/05/2000
Godkänd; 2000; 20080612 (tb)2016-10-032016-10-03Bibliographically approved