U.S. patent application number 12/294796 was filed with the patent office on 2010-07-01 for apparatus and method for sizing testing.
This patent application is currently assigned to Industry-Academ. Coop Found. Gyeongsang Nat. Univ.. Invention is credited to Chul-hwan Kim, Jong-cheol Kim.
Application Number | 20100163201 12/294796 |
Document ID | / |
Family ID | 38581310 |
Filed Date | 2010-07-01 |
United States Patent
Application |
20100163201 |
Kind Code |
A1 |
Kim; Chul-hwan ; et
al. |
July 1, 2010 |
APPARATUS AND METHOD FOR SIZING TESTING
Abstract
A method of measuring a Stockigt sizing degree of a paper or
hoard is provided. The method includes: placing a paper or board,
to which FeCl.sub.3 (II) is dropped or applied, on NH.sub.4SCN
solution; sequentially capturing, by using a camera, a process of
forming reddish brown Fe(SCN).sub.3 wile the FeCl.sub.3 (II) meets
the NH.sub.4SCN solution penetrating in a thickness direction of
the specimen, and recording RGB values of droplet image of the
reddish brown Fe(SCN).sub.3; converting the RGB values into HSV
values; recording hue (H) value of the HSV values with respect to
time; and checking a point where a differentiation value of the H
value recorded with respect to time becomes maximum.
Inventors: |
Kim; Chul-hwan; (
Gyeongsangnam-do, KR) ; Kim; Jong-cheol; (Seoul,
KR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Industry-Academ. Coop Found.
Gyeongsang Nat. Univ.
Jinju-si, Gyeongsangnam-do
KR
|
Family ID: |
38581310 |
Appl. No.: |
12/294796 |
Filed: |
April 10, 2006 |
PCT Filed: |
April 10, 2006 |
PCT NO: |
PCT/KR2006/001296 |
371 Date: |
September 26, 2008 |
Current U.S.
Class: |
162/198 ;
162/263 |
Current CPC
Class: |
D21H 21/16 20130101;
G01N 33/34 20130101 |
Class at
Publication: |
162/198 ;
162/263 |
International
Class: |
D21F 11/00 20060101
D21F011/00; D21F 7/00 20060101 D21F007/00 |
Claims
1. A method of measuring a sizing degree of a sized paper or board,
comprising: placing a paper or board specimen, to which a first
reagent is applied, on a second reagent; sequentially capturing, by
using a camera, a process of forming compound taking on a
predetermined color wile the first reagent meets the second reagent
penetrating in a thickness direction of the specimen, and recording
RGB values of droplet image of the compound; converting the RGB
values into HSV values; recording hue (H) value of the HSV values
with respect to time; and measuring the sizing degree by checking a
point where a differentiation value of the H value recorded with
respect to time becomes maximum.
2. The method of claim 1, wherein the first reagent is FeCl.sub.3
(II), the second reagent is NH.sub.4SCN solution, and the compound
is reddish brown Fe(SCN).sub.3.
3. The method of claim 1, wherein the recording of the RGB values
of the droplet image of the compound comprises: obtaining
sequential images showing color changes of the droplet of the
compound with respect to time; removing background image from the
sequential images obtained a segmentation processing using a color
binarization method; and extracting only shape of droplet.
4. A method of measuring a Stockigt sizing degree of a sized paper
or board, comprising: placing a paper or board, to which FeCl.sub.3
(II) is dropped or applied, on NH.sub.4SCN solution; sequentially
capturing, by using a camera, a process of forming reddish brown
Fe(SCN).sub.3 wile the FeCl.sub.3 (II) meets the NH.sub.3SCN
solution penetrating in a thickness direction of the specimen, and
recording RGB values of droplet image of the reddish brown
Fe(SCN).sub.3; converting the RGB values into HSV values; recording
hue (H) value of the HSV values with respect to time; and measuring
the sizing degree by checking a point where a differentiation value
of the H value recorded with respect to time becomes maximum.
5. An apparatus for measuring a sizing degree of a sized paper or
board, comprising: a unit for applying a first reagent on a paper
or board specimen; a unit for playing the paper or board specimen
on a second reagent solution; an image capturing unit for
sequentially capturing a process of forming compound taking on a
predetermined color wile the first reagent meets the second reagent
penetrating in a thickness direction of the specimen, and recording
RGB values of droplet image of the compound; a unit for converting
the RGB values into HSV values; and a unit for recording hue (H)
value of the HSV values with respect to time, and measuring the
sizing degree by checking a point where a differentiation value of
the H value recorded with respect to time becomes maximum.
6. The apparatus of claim 5, wherein the image capturing device
obtains sequential images showing color changes of the droplet of
the compound with respect to time, removes background image from
the sequential images obtained a segmentation processing using a
color binarization method, and extracts only shape of droplet.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a stockigt sizing
testing method, and in particular, to a stockigt sizing testing
method with reliability and reproducibility, the method including:
placing a paper or board, to which FeCl.sub.3 (H) is dropped or
applied, on NH.sub.4SCN solution; sequentially capturing, by using
a camera, a process of forming reddish brown Fe(SCN).sub.3 wile the
FeCl.sub.3 (II) meets the NH.sub.4SCN solution penetrating in a
thickness direction of the specimen, and recording RGB values of
droplet image of the reddish brown Fe(SCN).sub.3; converting the
RGB values into HSV values; recording hue (H) value of the HSV
values with respect to time; and checking a point where a
differentiation value of the H value recorded with respect to time
becomes maximum.
BACKGROUND ART
[0002] To increase resistance against liquid wetting and
penetration, a sizing process is performed on most papers or
boards, except tissues and sanitary papers. In such a sizing
process, since cellulose containing hydrophilic hydroxyl radical
(--OH) is the main component of the paper, a rosin acid sizing
agent or neutral sizing agent such as Alkyl Ketene Dimer (AKD) and
Alkenyl Succinic Anhydride (ASA) is added to a wet-end system of a
paper making process so as to provide water resistance. Examples of
a measuring method for evaluating sizing degree of the sized paper
include a Cobb testing method, a Hercules testing method, a
Stockigt testing method, a Carson curl method, a contact angle
measuring method, and a Drop testing method. Among them, the
Stockigt testing method is widely used.
[0003] According to the Stockigt testing method using liquid
penetration, as stipulated in Tappi Useful Method UM-429 and KS
M7025, after placing a paper specimen in which a ferric chloride
(FeCl.sub.3) is dropped or painted on an ammonium thiocyanate
(NH.sub.4SCN) solution, a sizing degree is measured using color
development occurring at a time point when the two liquids of
NH.sub.4SCN and FeCl.sub.3 are penetrated in a thickness direction
(z direction) of the paper to thus form a ferric thiocyanate
(Fe(SCN).sub.3). Color changes in the measurement of the Stockigt
sizing degree are illustrated in FIG. 1.
[0004] In this method, however, the recognition of the color
development time may be different according to each measurer's
subjective point of view. Therefore, it is difficult to verify
significant difference of the sizing degree with respect to the
very highly sized papers.
[0005] That is, the Stockigt sizing measuring method is to measure
the sizing degree of paper or board by measuring the time point
when FeCl.sub.3 and NH.sub.4SCN reacts to cause color development.
Since the sizing degree is the time when the reddish brown appears,
error according to measurers is great. FIGS. 2 and 3 illustrates
changes of Stockigt sizing degree with respect to amount and height
of FeCl.sub.3, showing these errors.
[0006] Accordingly, in measuring the Stockigt sizing degree for
evaluating the water resistance characteristic of the paper, there
is demanded a standardized sizing degree measuring method that can
overcome the error of measurement results due to obscurity of the
measuring method and the measurer's subjective point of view.
DISCLOSURE OF INVENTION
Technical Solution
[0007] An object of the present invention is to substantially solve
at least the above problems and/or disadvantages and to provide at
least the advantages below. Accordingly, an object of the present
invention is to provide a reliable and objective method of
measuring a sizing degree of a paper.
[0008] Another object of the present invention is to provide a
reliable and objective method of measuring a Stockigt sizing
degree.
[0009] According to one aspect of the present invention, a method
of measuring a sizing degree of a sized paper or board includes:
placing a paper or board specimen, to which a first reagent is
applied, on a second reagent; sequentially capturing, by using a
camera, a process of forming compound taking on a predetermined
color wile the first reagent meets the second reagent penetrating
in a thickness direction of the specimen, and recording RGB values
of droplet image of the compound; converting the RGB values into
HSV values; recording hue (H) value of the HSV values with respect
to time; and checking a point where a differentiation value of the
H value recorded with respect to time becomes maximum.
[0010] According to another aspect of the present invention, a
method of measuring a Stockigt sizing degree of a sized paper or
board includes: placing a paper or board, to which FeCl.sub.3 (II)
is dropped or applied, on NH.sub.4SCN solution; sequentially
capturing, by using a camera, a process of forming reddish brown
Fe(SCN).sub.3 wile the FeCl.sub.3 (H) meets the NH.sub.4SCN
solution penetrating in a thickness direction of the specimen, and
recording RGB values of droplet image of the reddish brown
Fe(SCN).sub.3; converting the RGB values into HSV values; recording
hue (II) value of the HSV values with respect to time; and checking
a point where a differentiation value of the H value recorded with
respect to time becomes maximum
DESCRIPTION OF DRAWINGS
[0011] FIG. 1 illustrates color change during the measurement of
Stockigt sizing degree;
[0012] FIG. 2 illustrates a change of the Stockigt sizing degree
with respect to dropping height of FeCl.sub.3;
[0013] FIG. 3 illustrates a change of the Stockigt sizing degree
with respect to dropping volume of FeCl.sub.3;
[0014] FIG. 4 illustrates sequential still images obtained during
the Stockigt test according to measurement time;
[0015] FIG. 5 illustrates a segmentation processing of extracting
only a droplet shape of FeCl.sub.3 solution, except a background
image;
[0016] FIG. 6 illustrates a change of HSV during the measurement of
Stockigt sizing degree;
[0017] FIG. 7 illustrates a change of H with respect to time during
the measurement of Stockigt sizing degree;
[0018] FIG. 8 illustrates a differential change of H with respect
to time during the measurement of Stockigt sizing degree;
[0019] FIG. 9 illustrates mask used to calculate a differential
change of H with respect to during the measurement of the Stockigt
sizing degree;
[0020] FIG. 10 illustrates a Stockigt sizing testing apparatus
according to the present invention; and
[0021] FIG. 11 illustrates the comparison of Stockigt sizing
measurement results according to the related art and the present
invention.
BEST MODE
[0022] Preferred embodiments of the present invention will be
described herein below with reference to the accompanying drawings.
In the following description, well-known functions or constructions
are not described in detail since they would obscure the invention
in unnecessary detail.
[0023] Hereinafter, the present invention will be described in
detail with reference to the accompanying drawings.
[0024] Paper used in this invention is a paper of 70 g/m.sup.2 made
by an experimental Tappi standard sheet machine, based on Tappi T
205, using a paper material beat up to 400 mL CSF through an
experimental Valley beater using Canadian Radiata pine ECF
coniferous bleached kraft pulp.
[0025] Alkyl Ketene Dimer (AKD) used in the paper sizing process
added 0, 0.2, 0.4, 0.6, 0.8, and 1% with respect to ovendry weight
of the paper. To dispersion and fixing of the AKD, 0.3% cationic
starch with respect to the ovendry weight of pulp was added. Before
the beat paper material, AKD, and the cationic starch were placed
into the Tappi standard sheet machine, they were agitated at 800
rpm for 30 seconds using the experimental disperser.
[0026] Reagent used in the Stockigt sizing degree test used 7%
ferric chloride (FeCl.sub.3) (II) solution and 6% ammonium
thiocyante (NH SCN) solution according to the regulation digital
video camcorder and CMOS digital camera were used.
[0027] The Stockigt sizing degree testing method includes a method
of TAPPI Useful Method UM 429 and a method of KS M 7025. In the
TAPPI Useful Method UM 429, FeCl.sub.3 is applied thinly on a test
specimen, and NH.sub.4SCN solution is dropped on the specimen. A
time is measured until perfect reddish brown appears on the
solution to which FeCl.sub.3 is applied, and the measured time is
represented as the sizing degree. On the contrary, in the KS M
7025, 2% FeCl.sub.3 (II) solution is dropped on a paper specimen,
and the specimen is placed on 1% NH.sub.4SCN solution. A time is
measured until three or more reddish brown spots appear on the
FeCl.sub.3 (II) solution, and the measured time is represented as
the sizing degree.
[0028] This invention used the method of TAPPI Useful Method UM 429
and recorded the time when perfect reddish brown appears as an
ending point of the sizing degree measurement.
[0029] To provide reliability and reproducibility of the Stockigt
test results, algorithm for determining color development time is
constructed using sequential image input, division, and color
conversion functions so as to automatically perceive the color
de-velopment time while minimizing all error that may occur during
the sizing degree measurement.
[0030] Since the Stockigt sizing degree test method measures the
time when the color of FeCl.sub.3 dropped into the paper specimen
is changed into perfect reddish brown, color changes of droplet
according to time is required to be sequentially recorded in order
for a computer to automatically recognize the color change during
the measurement. Therefore, the automatic image acquisition
developed in this study is obtained according to time, and these
obtained images are called sequential image. As illustrated in FIG.
4, sequential images obtained during the Stockigt test are sequence
of still images according to measurement time, appearing 3-D shape.
FIG. 4 illustrates still images obtained according to measurement
time during the Stockigt test.
[0031] To trace only color change during the Stockigt test, only
shape of FeCl.sub.3 at T.sub.i must be extracted among the
sequential images. The only shape of the droplet, except background
image, is extracted so as to obtain accurate color value of the
solution varying with time. This operation is called a segmentation
processing. FIG. 5 illustrates the segmentation processing to
extract only the shape of droplet of FeCl.sub.3, except background
image.
[0032] The segmented image means an image of only droplet, except
the background image, as illustrated in FIG. 5. For this
segmentation, a color binarization widely used in an image analysis
is used.
[0033] To quantify color changes of droplet from the sequential
images, only color must be detected from the respective images. To
find the color change of FeCl.sub.3 from initial color to reddish
color, it can be assumed that hue among color components is
important. By quantifying the hue value, the color development time
was found. However, each pixel value obtained from the droplet
image outputted from a computer is expressed as a combination of
red (R), green (B), and blue (B), not the hue values. These RGB
values are significantly different from human color perception.
Therefore, these RGB values are required to convert into hue (H),
saturation (S), and value (V).
[0034] Using HSV model, color can be divided into hue, saturation,
and value. Therefore, each color components can be observed in
linear terms.
[0035] Although there are several methods of converting RGB into
HSV, a following method is widely used. When an input value is
converted into HSV, RGB values are first converted into
YC.sub.1C.sup.2 values using Eq. 1 below.
[ Y C 1 C 2 ] = [ 1 3 1 3 1 3 1 - 1 2 - 1 2 0 - 3 2 3 2 ] ( 1 )
##EQU00001##
[0036] YC.sub.1C.sub.2 values are converted into HSV coordinate
system using Eq. 2 below.
V=Y
S= {square root over (C.sub.1.sup.2-C.sub.2.sup.2)}
If C.sub.2.ltoreq.0, then H=cos
Else H=2.pi.-cos (2)
[0037] Value (V) represents a mean black and white gray scale, Hue
(H) represents color that is not influenced by shadow due to
optical point, and Saturation (S) represents fineness of hue. The
HSV values are normalized in a range of 0 to 255.
[0038] A method of calculating a specific vector of a color and a
method of determining a color development time are proposed. To
determine the time when the color is changed, characteristic vector
of hue among the division regions of the sequential images is
calculated.
H={.eta..sub.1, .eta..sub.2, .eta..sub.3, . . . , .eta..sub.i, . .
. , .eta..sub.N}
.eta..sub.i=.parallel.h.sub.i.parallel. (3)
[0039] where i: time of sequential image, N: number of entire
acquired images, H: set of characteristic vectors of sequential
image, .eta..sub.i: i.sup.th characteristic vector, h.sub.i: colors
con-stituting i.sup.th image.
[0040] In Eq. (3), the set of characteristic vectors are expressed.
This model expresses changes of liquid color within the sequential
images. Each component of H means an average value of hue.
[0041] FIG. 6 illustrates change of HSV during the measurement of
Stockigt sizing degree. As illustrated in FIG. 6, the set expressed
as a graph can be considered as changes of hue values, that is,
characteristic vectors with respect to time.
[0042] FIG. 7 illustrates changes of H with respect to time during
the measurement of Stockigt sizing degree. In FIG. 7, time t is a
color development time when reddish brown appears.
[0043] Among several methods, a differentiation method was used.
FIG. 8 illustrates dif-ferentiation changes of H with respect to
time during the measurement of Stockigt sizing degree. This
differentiation method can be expressed as Eq. (4) below.
.gradient. H = .differential. H .differential. x ( 4 )
##EQU00002##
[0044] To apply to a discrete value, a mask of FIG. 9 was actually
used. That is, FIG. 9 illustrates a mask used to calculate
differentiation change of H with respect to time during the
measurement of Stockigt sizing degree.
[0045] The differentiation is locally performed using the mask of
FIG. 9(A) like in Eq. (5) below.
.gradient.f.apprxeq.|z.sub.1-z.sub.2| (5)
[0046] In Eq. (5), the differentiation value of the interest point
z.sub.2 is similar to difference between adjacent points z.sub.1
and z.sub.3, and a value of each mask is illustrated in FIG. 9(B).
This mask is sequentially applied to a function f. This method is
called a convolution.
[0047] FIG. 10 illustrates an apparatus for measuring the Stockigt
sizing degree according to the present invention. The apparatus
includes an automatic liquid dispenser for applying a first reagent
on a paper or board specimen, and a specimen shifter for placing
the paper or board specimen on a second reagent. Also, an image
capturing device sequentially captures a process of forming a
compound of a predetermined color while the first reagent and the
second reagent penetrating in a thickness direction of specimen are
encountered, and records RGB values of droplet images of the
compounds. A computer with software converts the RGB values
captured by the image capturing device into HSV values, records
changes of H with respect to time, and checks a point where a
differentiation value with respect to time is changed to the
maximum.
[0048] FIG. 11 illustrates the measurement results of Stockigt
sizing degree according to the related art and the present
invention. As illustrated in FIG. 11, 0.4% or more of AKD is added
to the sheet and thus the sizing degree measured by the related art
is higher than that measured by the automatic measuring method.
Also, error angle of the sizing degree measured according to
addition level of the AKD exhibits higher change than that measured
by the automatic measuring method of the present invention. On the
contrary, the sizing degree measured by the automatic measuring
method of the present invention is similar to the values measured
by the related art while increasing the addition of AKD. However,
it can be easily checked that error range is much smaller.
According to the conventional measurement, an ending point where
reddish brown appears is read, based on the measurer's subjective
point of view. Therefore, error range is large with respect to the
same specimens. Therefore, the present invention can obtain the
reproducible results.
[0049] According to the present invention, the method of measuring
a Stockigt sizing degree of a sized paper or board includes:
placing a paper or board, to which FeCl.sub.3 (II) is dropped or
applied, on NH.sub.4SCN solution; sequentially capturing, by using
a camera, a process of forming reddish brown Fe(SCN).sub.3 wile the
FeCl.sub.3 (II) meets the NH.sub.4SCN solution penetrating in a
thickness direction of the specimen, and recording RGB values of
droplet image of the reddish brown Fe(SCN).sub.3; converting the
RGB values into HSV values; recording hue (H) value of the HSV
values with respect to time; and checking a point where a
differentiation value of the H value recorded with respect to time
becomes maximum.
[0050] While the invention has been shown and described with
reference to certain preferred embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention as defined by the appended claims.
* * * * *