Abstract: The invention relates to a device for monitoring a web. The device includes cameras imaging the web in order to take digital images of the web from a transverse area of the web at the imaging frequency. Each camera includes an image element, which consists of pixels. The individual pixels of the imaging element of the camera are real image-elements. The real image-elements are arranged to combine to form effective image-elements of the web in the machine direction. In addition, the cameras used in the device are matrix cameras, the imaging elements in which are arranged to be exposed simultaneously. The real image-elements are arranged to be combined to form effective image-elements by exploiting the binning function of the matrix camera. The device includes a strobe-lighting unit, the synchronization of which is arranged in step with the exposure of the matrix cameras, the imaging periods being common to all the cameras.

Abstract: A method for guiding web patching, using a re-reeler, in connection with a paper machine and an off-line coating machine, in which method a defect map of the web is created on the paper machine, to show deviations some of which are shown on the coating machine, using selected criteria, to the operator, the deviations being patched using the re-reeler, guided by the defect map and preset patching rules. On the coating machine, the virtual location of the selected deviations is monitored through the coating machine and if a possible web break occurs, a deviation is localized relative to the web break, and on the basis of this monitoring, feedback is provided to the patching rules of the re-reeler, in order to optimize them.

Abstract: The invention relates to a LED light matrix (14) equipped with impulse means for illuminating a moving object (10) in a selected area (11) from an oblique direction for video imaging, said LED light matrix (14) including a group of LEDs (15, 16) each equipped with optics for focusing the light produced by the LED, and with the group being located substantially obliquely relative to the object to be illuminated. Separate LEDs (15, 16) of the LED light matrix (14) are so oriented that the intensity distribution of illumination in the selected area (11) is weighted proportionally to the distance.

Abstract: A method for guiding web patching, using a re-reeler, in connection with a paper machine and an off-line coating machine, in which method a defect map of the web is created on the paper machine, to show deviations some of which are shown on the coating machine, using selected criteria, to the operator, the deviations being patched using the re-reeler, guided by the defect map and preset patching rules. On the coating machine, the virtual location of the selected deviations is monitored through the coating machine and if a possible web break occurs, a deviation is localized relative to the web break, and on the basis of this monitoring, feedback is provided to the patching rules of the re-reeler, in order to optimize them.

Abstract: The invention relates to a device for monitoring a web. The device includes cameras imaging the web in order to take digital images of the web from a transverse area of the web at the imaging frequency. Each camera includes an image element, which consists of pixels. The individual pixels of the imaging element of the camera are real image-elements. The real image-elements are arranged to combine to form effective image-elements of the web in the machine direction. In addition, the cameras used in the device are matrix cameras, the imaging elements in which are arranged to be exposed simultaneously. The real image-elements are arranged to be combined to form effective image-elements by exploiting the binning function of the matrix camera. The device includes a strobe-lighting unit, the synchronization of which is arranged in step with the exposure of the matrix cameras, the imaging periods being common to all the cameras.

Abstract: The invention relates to a LED light matrix (14) equipped with impulse means for illuminating a moving object (10) in a selected area (11) from an oblique direction for video imaging, said LED light matrix (14) including a group of LEDs (15, 16) each equipped with optics for focusing the light produced by the LED, and with the group being located substantially obliquely relative to the object to be illuminated. Separate LEDs (15, 16) of the LED light matrix (14) are so oriented that the intensity distribution of illumination in the selected area (11) is weighted proportionally to the distance.

Abstract: The invention relates to a method for monitoring a rapidly-moving paper web. In the method, images of the rapidly-moving web are taken with cameras at several consecutive positions, of the same cross-direction point of the web. The images are analysed in real time in order to detect deviations, and the position data of the deviations are determined. Each deviation found in the analysis is connected to an event chain in real time using a selected criterion on the basis of the position data of each deviation. Images containing a deviation are shown to the operator immediately as event chains.

Abstract: The invention relates to a method for imaging and analysing the formation and surface topography of a fast-moving web or for the statistical analysis of impurities and spots. An electronic matrix camera is used to take images of a web moving at least 5 m/s, the exposure time of the electronic shutter of the camera being adjusted so that the sum of the static pixel size of the web and the dynamic imaging inaccuracy caused by movement is at most about 0.6 mm in the direction of travel. The exposure time is shorter than 25 &mgr;s.