On-Line Measurement of Paper Shrinkage Using Image Analysis

Abstract The paper describes advances made in a computer method for the detection of paper shrinkage during the drying stages. The technique is based on two-dimensional Fourier transformations used to detect those periodic marks left on the paper by the wire during the formation stage. These marks are obtained from images of paper taken by low-cost CCD cameras for a later matching with those of the wire. Differences in separation of lines for the two cases are due to paper shrinkage. Finally some comments on hardware considerations of the sensor design and potentials of the method for the paper and graphic industry are given