International Paper Company

James F Suska

Kapil Mohan Singh

William R Shields

Jody MacDonald

David W Vahey

Ronald A Stone

A paper web formation measurement system provides on-line measurement and control of visual properties of a moving web of paper. The measurement system includes an image acquisition system for capturing images of the moving web, and an image analysis system for analyzing captured images. The image acquisition system includes a strobe lighting system for backlighting the moving web and a charge injection device (CID) camera for capturing light transmitted through the web to form an image of the web in non-standard (non-RS-170), full frame format. Captured images are digitized by the image analysis system to 256 graylevel and analyzed to produce a mathematical formation index representing visual properties of the web. The mathematical formation index, which is derived from a graylevel distribution histogram, is presented to paper production personnel to enable on-line adjustment of process variables to maximize paper quality. The image analysis system is also configured to ascertain the distribution of flocs and voids within the image. The mathematical formation index may be adjusted to reflect the distribution of flocs and voids within the web.

Measurement of visual characteristics of paper

A system for determining characteristics of objects in wood pulp includes a pulp sampling and dilution system for diluting and dispersing samples of pulp, and an imaging/analysis system for capturing images of pulp objects, including fibers, and analyzing the captured images. Samples of pulp are provided to a dispersion tank where pulp is dispersed within a liquid to form a wood pulp slurry having a consistency in the range of from about 0.01 to about 0.001 percent. The dispersed pulp is conducted to a transparent flow cell for imaging and analysis of pulp objects. Light radiating from a light source is reflected off surfaces of objects within the dispersed pulp, producing scattered light. One or more cameras capture scattered light from objects as the objects pass through a camera's field of view. The output of the cameras are digitized and filtered to eliminate motion blur, and the filtered visual image displayed on a monitor. Each pixel of the image is compared to a graylevel threshold, and pixels meeting the graylevel threshold are converted to objects. Object pixels are averaged and compared to a critical mean graylevel threshold. If the average does not meet the critical mean, the object is eliminated from further analysis. Objects meeting the critical mean are analyzed using various size and shape filters to determine properties of the objects. The measured object properties are then displayed on the computer monitor with operator selectable parameters as well as stored in archival files and spreadsheet files, and periodically reviewed by machine operators to enable proper adjustment of process variables.

Measurement of paper pulp and fiber visual characteristics

A method for determining the tendency of a non-woven web to curl, where the web has a machine direction (MD), a cross-machine direction (CD) and the web includes a wire side and a felt side. The method comprises determining a wire ratio which is the ratio of the number of fibers oriented in the MD to the number of fibers oriented in the CD, where the fibers are associated with the wire side of the web, a felt ratio which is the ratio of the number of fibers oriented in the MD to the number of fibers oriented in the CD, where the fibers are associated with the felt side of the web, and determining the wire to felt ratio which is a measure of the tendency of the web to curl.

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West Milford, NJ, United States of America

James F Suska