Detection and characterization of web vibrations by artificial vision

Abstract

In this paper, we address the problem of the detection of transverse web vibrations by means of a digital camera and a laser dots pattern device. For this purpose, we briefly present some video processings which yield an accurate location of the projection of laser dots in the image. However, the main contribution of this work is in the new approach developed for estimating, on-line, transverse web vibration frequencies with a geometrical method and without contact. To do so, some techniques commonly used in the computer vision field are extended to some classes of non-rigid objects suitable to account for a part of an elastic web. Finally, we compare the estimated frequencies with those provided by a simple vibrating elastic string model, in motion.