US 5,393,378 AGranted

Method for measuring and controlling fiber variations in paper sheet

AssigneeIshikawajima-Harima Jukogyo Kabushiki Kaishi

InventorsMasahiro Yakabe, Satoshi Suzuki, Sadao Degawa, Shigeki Murayama, Koichi Ishibashi, Ikuo Nakashima, Koji Sakai

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Abstract

A formation control method and apparatus in which an image is emitted from a light source and transmitted through a predetermined area of paper an captured by a camera to be displayed as transmitted light image on a display of an image processing computing element, the transmitted light image displayed on the display being image-analyzed to obtain formation factor for quantification of the formation, J/W ratio and the like being optimized by fuzzy control using membership functions based on said formation factor so as to improve the formation.

Claims10

Dependent claims

A method for generating a paper quality membership function to be used in an apparatus for controlling the degree of fiber variance in paper sheet, comprising the steps of:

(a) picking up an image of transmitted light from a light source on an area of paper by a plurality of cameras with different visual fields, the cameras being arranged so that images of the transmitted light are picked up by the cameras concurrently in comparatively wide and narrow visual fields and are introduced to a display unit of an image processing computing element, there being means provided for changing the visual field introduced to the display unit;
(b) dividing the image of the transmitted light on the display unit into a predetermined size and number of windows, the windows comprising pixels;
(c) measuring the tone density of each pixel, and the tone density of each window from the tone density of the pixels comprising the window;
(d) calculating values chosen from at least one of the following:
an average value of tone density and a primary variance of tone density of each window from the tone density of each pixel,
an average value of the primary variance of the tone density for all of the windows,
a secondary variance of tone density for all of the windows, and
a variance of average values of tone density of each window;
and
(e) using one of or at least two in combination of said values as a formation factor;
(f) changing the visual field transmitted to said display unit by said plurality of cameras;
(g) repeating steps (a)-(e) one or more times to obtain different formation factors;
(h) generating a paper quality membership function from the different formation factors obtained:
and
(i) using said paper quality membership function to control the degree of fiber variance in said apparatus.

12 more elements

A method for controlling the degree of fiber variations in paper sheet, comprising the steps of:

(1) generating a plurality of paper quality membership function curves for categorizing the quality of the paper into categories ranging from lowest to highest quality, the categories corresponding to formation factors of the paper, the formation factors of the paper being obtained by
(a) picking up an image of transmitted light from a light source on an area of paper by a plurality of cameras with different visual fields, the cameras being arranged so that images of the transmitted light are picked up by the cameras concurrently in comparatively wide and narrow visual fields and are introduced to a display unit of an image processing computing element, there being provided means for changing the visual field introduced to the display unit;
(b) dividing the image of the transmitted light on the display unit into a predetermined size and number of windows, the windows comprising pixels;
(c) measuring the tone density of each pixel, and calculating the tone density of each window from the tone density of the pixels of which the window is comprised;
(d) calculating values chosen from at least one of the following:
an average value of tone density and a primary variance of tone density of each window from the tone density of each pixel,
an average value of the primary variance of tone density for all of the windows,
a secondary variance of tone density for all of the windows, and
a variance of average values of tone density of each window;
and
(e) using one of or at least two in combination of said values as a formation factor;
(f) changing the visual field transmitted to the display unit by said plurality of cameras and repeating the steps (a)-(e) so as to obtain a different formation factor corresponding to the different camera position;
(g) repeating step (f) one or more times so as to obtain a number of formation factors from which a paper quality membership function curve can be calculated:
(h) repeating steps (a)-(g) for a plurality of different paper sheets having highest to lowest quality so as to thereby obtain said plurality of paper quality membership function curves;
(2) generating a plurality of separate operation control membership function curves corresponding to operation factors comprising, respectively, changes of J/W ratio, changes in foil angle, and changes in deflector pushing degree, said changes being in response to each of the paper quality membership function curves generated in step (1),
(3) obtaining a degree of matching at intersections of the paper quality membership function curves with each of the operation control membership curves,
(4) for the control of each of said operation factors J/W ratio, foil angle, and deflector pushing degree, in sequence,
(A) obtaining in correspondence to each of the matching degrees, results of the estimated changes of the operation factor from the respective operation control membership function curves,
(B) overlapping and synthesizing results of the estimated change of the operation factor to generate final operation control membership functions providing a final estimated result of the change,
(C) determining the actual change to be effected with regard to the operation factor based on the final operation control membership function,
(D) adjusting the operation factor based on said determined actual change, and
(E) repeating steps (A)-(D) for each of the remaining operation factors.

19 more elements

Dependencies are inferred from the claim text.