KR100633057B1 - Apparatus and Method for Sizing Testing - Google Patents

Abstract

The present invention relates to a method for measuring the size of the paper or paperboard, specifically, to drop the FeCl ₃ or painted paper or paperboard specimen on the NH ₄ SCN solution, and to penetrate in the thickness direction of the FeCl ₃ and the specimen The red-brown Fe (SCN) ₃ formation process formed by meeting with NH ₄ SCN is continuously photographed with a camera to record the RGB value of the Fe (SCN) ₃ droplet image, and is converted into an HSV value. Record the value over time, and check the point where the differential value (or slope) that differentiates the recorded change of H value into time is the maximum. It relates to how to measure.

Size, paper, cardboard, waterproofing, stachy heat

Description

Apparatus and Method for Sizing Testing

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the color change at the time of the measurement of a stachyhit.

2 is a view showing a change in the size of the Stekihit size chart according to the amount of FeCl ₃ falling.

FIG. 3 shows a sequence of still images according to measurement time obtained during a stachyhit test. FIG.

4 is a diagram illustrating a division process of extracting only the shape of droplets of a FeCl ₃ solution excluding a background image.

Fig. 5 is a graph showing the change in HSV shown in the stakihit size measurement.

Fig. 6 is a diagram showing the change of H with time appearing in the stakihit size measurement.

Fig. 7 is a diagram showing the differential change diagram of H with time shown in the stakihit size diagram measurement.

FIG. 8 shows a mask used for calculating the differential change in H over time shown in a stakihit size plot. FIG.

Fig. 9 is a diagram showing an apparatus for measuring a stakihit size diagram according to the present invention.

Fig. 10 is a diagram showing a comparison between the results of a conventional method and a stakihit size measurement according to the present invention.

The present invention relates to a method for measuring the level of stachyhit. Particularly, the reddish-brown Fe (SCN) ₃ formation process formed by meeting FeCl ₃ and NH ₄ SCN penetrating in the thickness direction of the specimen by placing FeCl ₃ on the NH ₄ SCN solution or placing painted paper or cardboard specimens in the camera Record the RGB values of the Fe (SCN) ₃ droplet images by successive shooting with HV, convert them to HSV values, and record the H value, which is the color value, among the HSV values over time, and record the change in the recorded H value as time. The present invention also relates to a method for measuring the size of a stakihit which can identify the point where the differential derivative value (or the slope) is maximized and ensure the reliability and reproducibility of determining the point as the size degree.

Most paper or paperboards (hereinafter, typically papers) except for tissues and sanitary papers are subjected to a sizing treatment in order to impart resistance to wetting and penetration of the liquid. For this sizing treatment, since cellulose having a hydroxyl group (-OH), which is a hydrophilic group, is a main component, rosin-based sizing agents, Alkyl Ketene Dimer (AKD) and Alkenyl Succinic Anhydride ( A method of adding a neutral size agent such as ASA) is used.

The measurement methods used to evaluate the size of the sized paper include Cobb test method, Hercules test method, Stockigt test method, Carson curl test method, contact angle measurement method, and Drop test method. Among them, the Stockigt test method is widely used.

The Stockigt test by liquid infiltration was carried out by placing ferric chloride (FeCl ₃ ) on a solution of ammonium thiocyanate (NH ₄ SCN) or painting a paper specimen, as specified in Tappi Useful Method UM-429 and KS M 7025. (NH ₄ SCN) and FeCl ₃ is a method of measuring the size by the color development phenomenon at the time when two liquids penetrate in the z direction of paper to form ferric thiocyanate (Fe (SCN) ₃ ). 1 is a view showing the color change when measuring the size of the stachyhit.

However, this method has a probability that the subject's subjectivity can be significantly involved in recognizing the color recognition time, and there is a problem that it is difficult to identify a significant difference in size for highly sized paper.

That is, the Stockigt method, which measures the size (or water repellency) of paper or paperboard by measuring the time when FeCl ₃ and NH ₄ SCN meet a color development reaction, takes time until a clear reddish brown color is shown. Since the time to recognize this shows a significant error for each measurer. Figure 2 is a diagram showing the change in the size of the Stekihit according to the amount and height of falling FeCl ₃ , this error is shown.

Therefore, in order to overcome the ambiguity of the measurement method and the error of the measurement result by the subject's subjectivity, the measurement method of the stockigt size for evaluating the water resistance characteristics of the paper is required.

Accordingly, an object of the present invention for solving the above problems is to provide a method for measuring the size of the objective and reliable sized paper.

Another object of the present invention is to provide a method for measuring the stakihit size of the objective and reliable sized paper.

In order to achieve the object of the present invention, the present invention is a step of placing the first reagent-coated paper or cardboard specimens in the second reagent solution, the first agent of the specimen and the first penetrating in the thickness direction of the specimen Recording a RGB value of the droplet image of the compound by continuously photographing a process of forming a compound having a constant color as two reagents meet, converting the RGB value into an HSV value, and color among the HSV values Measuring the size of the sized paper or paperboard comprising the steps of recording the value of H, which is a value over time, and identifying a point where the differential value obtained by differentiating the degree of change of the H value recorded over time is maximized. Provide a method.

In order to achieve the object of the present invention, the present invention is also the step of dropping or painted FeCl ₃ paper or cardboard specimens in NH ₄ SCN solution, infiltrating the FeCl ₃ of the specimen with the thickness direction of the specimen Recording the RGB value of the reddish brown Fe (SCN) ₃ droplet image by continuously photographing the process of forming reddish brown Fe (SCN) ₃ while meeting the NH ₄ SCN, wherein the RGB value is converted into an HSV value The step of recording the H value, which is the color value among the HSV value over time, and the step of identifying the point where the derivative value (or slope) that differentiates the degree of change of the H value recorded over time to the maximum It also provides a method for measuring the size of the stakihit of the sized paper or cardboard consisting of.

In addition to the above-described modifications, additions to the components, or various other embodiments for achieving the object of the present invention are possible.

The present invention relates to a method for measuring the size of stachyheat, by dropping the FeCl ₃ in a NH ₄ SCN solution or put a painted paper or cardboard specimen, while meeting the NH ₄ SCN penetrating in the thickness direction of the FeCl ₃ and the specimen The red-brown Fe (SCN) ₃ formation process is continuously taken with a camera to record the RGB value of the Fe (SCN) ₃ droplet image, and is converted into an HSV value. The method relates to a method for ensuring reliability and reproducibility of determining a point where a differential value (or slope) obtained by recording a change in recorded H value by time is maximized.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The paper used in the present invention is a basis weight obtained by using a lab valley beater from Canadian Radiata pine ECF conifer bleached kraft pulp to a laboratory square beater paper based on Tappi T 205. 70 g / m ² paper.

AKD (Alkyl Ketene Dimer) used for sizing of paper was added to 0, 0.2, 0.4, 0.6, 0.8, 1% based on the total weight of the paper. Cationic starch was added 0.3% to the total weight of the pulp for dispersion and fixation of AKD. Before adding the beaten paper, AKD and cationic starch to the herbicide, a laboratory dispersion machine was used for 30 seconds at a speed of 800 rpm.

Reagents used for the Stockigt size test were used with 7% ferric chloride (FeCl ₃ ) (II) and 6% ammonium thiocyante (NH ₄ SCN) solutions according to the method specified in TAPPI Useful Method UM 429. Digital Video Camcoder and CMOS Digital Camera were used to capture the process of color development.

The stockigt size test method is defined in TAPPI Useful Method UM 429 and in KS M 7025. In TAPPI Useful Method UM 429, FeCl ₃ was applied thinly on the test specimen, then the specimen was dropped on an NH ₄ SCN solution, and the time until complete reddish brown appeared on the FeCl ₃ coated solution was expressed in size. It is regulated. On the other hand, in KS M 7025, a drop of 2% FeCl ₃ (II) solution was dropped onto a paper specimen, and then the specimen was placed on a 1% NH ₄ SCN solution and three or more reddish brown spots appeared on a drop of FeCl ₃ (II) solution. The time until it is measured and it is prescribed | regulated to show that time as a size chart.

In the present invention, a method of recording the time point at which complete reddish brown appears as the end point of the size measurement was used according to the method specified in TAPPI Useful Method UM 429.

In order to give reliability and reproducibility of the results of the stachyhit test, the color development time is provided by providing the sequential image input, segmentation, and color conversion functions to automatically recognize the reproducible color development time while minimizing all errors that may occur during measurement. An algorithm for determining

The Stockigt size test is a method of measuring the time when the color of FeCl ₃ deposited on paper specimens turns completely reddish brown, so that the computer automatically recognizes the color change of the droplets over time in order to recognize the color change during the measurement. It is necessary to record. Therefore, the automatic image acquisition developed in this study is obtained over time, and the obtained images are called sequential images. As shown in FIG. 3, the continuous images obtained during the Stockigt test have a three-dimensional shape as a sequence of still images according to measurement time. FIG. 3 is a diagram showing the sequence of still images according to the measurement time obtained during such a stechheat test.

To track only the color change process during the Stockigt test, only the shape of the FeCl ₃ solution should be extracted from the sequence image at time T _i . The purpose of extracting only the shape of the droplets, excluding the background image except the image of the FeCl ₃ solution, is to obtain an accurate color value of the solution that changes with time, and this step is called a segmentation processing step. 4 is a diagram illustrating a division process of extracting only the shape of droplets of a FeCl ₃ solution excluding such a background image.

The segmented image refers to an image of only the droplets excluding the background image as shown in FIG. 4. For this segmentation, the color binarization method, which is frequently used in image analysis, is used.

In order to quantify the color change of the droplet from the continuous image, only color should be detected from each image. To find the process of changing from the initial color of FeCl ₃ to reddish brown, it can be assumed that hue is an important factor among the elements of color. Here, the color value was quantified to find the color development time, which is the time when the color of the liquid changes. However, pixel values obtained from computer-generated droplet images are represented by a combination of red (R), green (G), and blue (B) values, not color values. However, since these RGB values are quite different from human perception of color, it is necessary to convert them to hue (Hue, H), saturation (S), and brightness (Value, V) values. .

Using the HSV model, color can be separated into hue, saturation, and lightness, so that each color element can be observed from a linear perspective.

There are many ways to convert RGB to HSV, but the following are the most widely used. When converting the input value to HSV, first convert the RGB value to YC ₁ C ₂ value using Equation 1 below.

The YC ₁ C ₂ value is converted into the HSV coordinate system by Equation 2 below.

Where Value (V) represents the average black and white gradation, Hue (H) represents the color unaffected by the light spot shadow, and Saturation (S) represents Hue's purity. At this time, each HSV value is used by normalizing from 0 to 255.

We propose a method for obtaining a feature vector of color and a method for determining a color development time point. In order to determine the time point at which the color changes, a feature vector of a color hue is obtained from the divided regions of the sequential image.

Where i is the time of the sequential image, N is the total number of acquired images, H is the set of feature vectors of the sequential image, η _i i th feature vector, h _i : Colors constituting the i th image.

In Equation 3, a set of feature vectors is represented. This model is intended to represent the change of liquid color in a sequential image. Each element of H represents an average value of colors represented by each still image.

It is a figure which shows the change of HSV which shows in the stachyhit size degree measurement. If this set is represented graphically, it can be seen as a change in the feature vector, that is, the color values, over time as shown in FIG. Feature vector η _i Has an average value of the colors represented by the i th image.

FIG. 6 is a diagram showing a change in H with time appearing in a stakihit size measurement. In the above figure, the time point t is the color development time point of reddish brown color to be found in this study.

Various methods can be suggested as a way of finding this, but the method by differential is used here. It is a figure which shows the derivative change degree of H with time shown in the stachyhit size figure measurement. This differential method can be expressed as Equation 4 below.

In order to apply to discrete values, the mask of FIG. 8 is actually used. That is, FIG. 8 is a diagram showing a mask used for calculating the degree of differential change in H over time shown in the stakihit size measurement.

Differentiation is performed locally using this mask applied to discrete values as in the form of FIG. 8 (a), and the equation is as follows.

<Equation 5>

의 미분 값은 주변점

와

사이의 차에 유사하였고, 각 마스크의 값은 도 8(b)와 같다. 이 마스크를 함수 f에 대해 순차적으로 적용시킨다. 이러한 방법을 컨볼루션(convolution)이라 부른다.Interest points as shown in Equation 5 above

The derivative of is the peripheral point

Wow

Similar to the difference between, and the value of each mask is shown in Figure 8 (b). Apply this mask sequentially to the function f . This method is called convolution.

Fig. 9 is a diagram showing an apparatus for measuring a stakihit size in accordance with the present invention. The device has an automatic liquid dispenser as a means of applying a first reagent to paper or cardboard specimens, and has a specimen mover as a means of placing the first reagent-coated paper or cardboard specimen in a second reagent solution. RGB values of the droplet image of the compound by continuously photographing a process of forming a compound having a constant color when the first reagent of the specimen and the second reagent penetrating in the thickness direction of the specimen meet. An image capturing device is provided as an image capturing means for recording an image, and the H value, which is a color value, among the converted and converted HSV values for converting the RGB values photographed by the image capturing means into HSV values over time. Record the degree of change and confirm the point where the derivative value obtained by differentiating the degree of change of the recorded H value over time is maximized. You have a computer with software installed.

10 is a diagram showing a comparison of the results of the measurement method with the existing method and the stakihit size according to the present invention. As shown in FIG. 10, when AKD was added to the sheet by 0.4% or more, the size measured based on the conventional method showed a higher value than that measured by the automatic measuring method. In addition, the error range of the size diagram measured for each level of AKD addition showed a larger variation than those measured by the automatic measurement method according to the present invention. On the other hand, the size measured by the automatic measuring method according to the present invention showed a tendency similar to the values measured by the conventional method as the amount of AKD added increased, but it was easily confirmed that the error range was much smaller. The measurement based on the conventional method showed a large margin of error for the same specimen because the reading point of the reddish brown color was read based on the subjective judgment of the measurer. Therefore, it can be confirmed that the method according to the present invention can obtain more reproducible results.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described in detail above, the FeCl ₃ (II) drop or painted paper or paperboard specimen is placed on the NH ₄ SCN solution of the present invention, while meeting with FeCl ₃ (II) and NH ₄ SCN penetrating in the thickness direction of the specimen The red-brown Fe (SCN) ₃ formation process is continuously taken with a camera to record the RGB value of the Fe (SCN) ₃ droplet image, and is converted into an HSV value. To record the point where the derivative (or slope) of the differential value (or slope) of the change in the recorded value of H is maximized, and then measure the size of the stachyhit size of the paper or paperboard that determines this point as the size. When used, a reliable and reproducible paper or paperboard size can also be provided.

Claims (6)

In the measuring method of the sized paper or cardboard specimens, Placing the first reagent-coated paper or cardboard specimen in the second reagent solution; Recording the RGB value of the droplet image of the compound by continuously photographing a process of forming a compound having a predetermined color while the first reagent of the specimen and the second reagent penetrating in the thickness direction of the specimen meet; ; Converting the RGB value to an HSV value; Recording the H value, which is a color value, among the HSV values over time; And Measuring the size of the paper or paperboard, including measuring the size of the paper or paperboard by identifying a point where the differential value obtained by differentiating the degree of change of the H value recorded with time becomes the maximum; Way. The method of claim 1, Wherein the first reagent is FeCl ₃ (II), the second reagent solution is NH ₄ SCN solution, and the constant color compound is reddish brown Fe (SCN) ₃ . . The method of claim 1, The recording of the RGB value of the droplet image of the compound may include obtaining a color change of the droplet of the compound over time as a sequential image and excluding a background image from the sequential image obtained by a segmentation processing method using a color binarization method. Method for measuring the size of the paper or cardboard specimens, characterized in that the step of extracting only the shape of the droplets. In the method of measuring the size of the stakihit of the sized paper or cardboard specimen, Dropping or coloring the FeCl ₃ (II) or painted paper or cardboard specimens into NH ₄ SCN solution; The process of forming reddish brown Fe (SCN) ₃ while meeting the FeCl ₃ (II) of the specimen and the NH ₄ SCN penetrating in the thickness direction of the specimen was continuously photographed with the camera to form the reddish brown Fe (SCN) ₃ droplet. Recording RGB values of the image; Converting the RGB value to an HSV value; Recording the H value, which is a color value, among the HSV values over time; And Determining the point at which the gradient, the degree of change of the H value recorded over time, is maximized and determining the point as a size diagram. In the measuring device, the size of the sized paper or cardboard specimen, Means for applying the first reagent to paper or cardboard specimens; Means for placing the first reagent coated paper or cardboard specimen in a second reagent solution; Imaging means for recording the RGB value of the droplet image of the compound by continuously photographing the process of forming the compound having a certain color as the first reagent and the second reagent penetrating in the thickness direction of the specimen meets ; Conversion means for converting the RGB value photographed by the image photographing means into an HSV value; The degree of change of the H value, which is a color value, is changed over time among the HSV values converted by the converting means, and the point where the derivative value obtained by differentiating the degree of change of the recorded H value with time is maximized. An apparatus for measuring the size of a sized paper or paperboard specimen comprising means for determining the size diagram. The method of claim 5, The image capturing means obtains a color change of the droplet of the compound over time as a sequential image, and extracts only the shape of the droplet from the sequential image obtained by the segmentation processing by the color binarization method. A device for measuring the size of a piece of paper or paperboard, characterized in that it is used.

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