Patent FI-109939-B (FI)
Title: Method and system for monitoring a paper web, a paper pulp or a wire traveling in a paper machine comprises imaging a monitored object with a video camera
Inventor: VALKONEN MIKA
IPC: G01B/
Filed: 1998-08-12
Granted: 2002-10-31
Abstract: A method for monitoring a paper web traveling in a paper machine comprises imaging a monitored object with a video camera (1), and storing an image in a digital form and analyzing the stored image. A method for monitoring a paper web traveling in a paper machine comprises: (i) Imaging a monitored object with a video camera (1), and (ii) storing an image in a digital form and analyzing the stored image, characterized by: (I) defining and delimiting within an image field to be stored a region of interest, as selected; (II) storing in a memory (2m, 3) a digitized picture of the image field constituting a monitored object and containing said delimited image section; and (III) analyzing the delimited image section of the memory-stored digitized image automatically by one or more of the following optional procedures: (a) comparing the delimited image section of the stored image with a similarly delimited image section of an image recorded from an ideal condition; (b) monitoring a change between the sequential images regarding the delimited image section only; or (c) comparing the number of shades of gray within the delimited image section of the stored image with preset limit numbers of shades of gray. Independent claims are also included for: (i) A system for monitoring a paper web traveling in a paper machine comprising: A video camera photographing a monitored object; and image processing equipment for storing and analyzing an image, characterized above. (ii) A method for monitoring paper pulp and/or a wire traveling in the twin wire section of a paper machine, the object to be monitored in said method comprising regions of the paper web and the wires closely associated with a wire-gap opening point characterized in that the object to be monitored is analyzed and imaged with a video camera (1); within the image field to be monitored is defined and delimited a region of interest; a number of digitized images are stored in a memory (2m, 3) from the monitored imaged field each of said images containing said region of interest; the delimited image section of a digitized image stored in the memory (2m, 3) is analyzed automatically with an image processing algorithm by utilizing one or more of the following procedures: (a) comparing the delimiting image section of the stored image with a similarly delimited image section of an image recorded from an ideal condition; (b) monitoring a change between sequential images regarding the delimited image section; (c) comparing the number of shades of gray within the delimited section of the stored image with preset limit numbers of shades of gray; or (d) applying image processing algorithms applicable to pattern recognition; and in a mass storage (4) for a subsequent analysis are recorded those digitized images in which the above analysis results in a discovery of a variation or change exceeding the present limit. (iii) A system for monitoring paper pulp web and/or a wire traveling in the twin wire section of a paper machine comprising a video camera (1) directed for imaging regions of the paper pulp and the wires closely associated with the wire-gap opening point; and image processing equipment for storing and analyzing an image, characterized above.