RU2256177C1 - Method for determining hairiness coefficients for cloth sheets on basis of computer image - Google Patents

Abstract

FIELD: textile industry.

SUBSTANCE: method includes bending cloth along one of filaments systems and image of bend line of cloth with hair is produced. Then received image is scanned in direction, perpendicular to this line, matrix of values of pixels brightness is received. On basis of matrix columns, said values are summed, brightness profile is built in form of curved line, and on its portion, matching light pixels, level of cloth ground is determined by averaging brightness parameters of these pixels. Analogically, background level is determined, at portion,, matching dark pixels, point is selected on curve in the middle of gap between cloth ground and background levels. Hair zone is determined by building through this point of tangent to curve and plotting vertical lines through points of intersection of tangent with levels of cloth ground and background, and hair height is determined on basis of number of pixels between these lines, and density of hair is determined by summing brightness of pixels.

EFFECT: higher precision.

5 dwg, 3 tbl

Description

The invention relates to the textile industry and can be used in a non-contact analysis of the structure of the fabric to study the indicators of hairiness in the laboratories of tissue testing.

A known method of controlling the quality of the yarn, in particular, along the length of the pile and its distribution along the length of the yarn, which consists in scanning the surface of the yarn with a camera and a radiation source, in registering the image of the surface of the yarn at a given length, in comparison with the recorded image converted to digital form, a digital signal proportional to the number of villi over a given length [1].

This method allows you to estimate the number of fibers on the surface of the yarn, while it is desirable that the villi are located separately from each other. This method is not suitable for measuring indicators of tissue hairiness, namely, the height of the pile density.

The closest way to the proposed one is the method implemented in the device for controlling the hairiness of the fabric [2], which consists in bending the fabric along one of the yarn systems, obtaining an image of the bending line of the fabric with pile, scanning this image, obtaining digital values corresponding to the brightness of the image, summing these values and comparing the obtained value with a given value.

This method allows to obtain a quantitative estimate of the area occupied by the image of the pile from the image of the inflection line of the fabric. According to the data obtained, they judge the density of the pile. Although the measurement of pile height values by this method is not provided, the height can be estimated from an enlarged image of a tissue sample directly on the monitor screen. This method does not provide high measurement accuracy, since it does not provide for automated determination of the boundaries of the pile zone. The values of pile height and density measured in this way may contain components about the soil of the fabric and lint-free space.

The technical result of the claimed invention is to improve the accuracy of measuring the height and density of the pile by automating the determination of the boundaries of the pile area.

The specified technical result is achieved by the fact that in the method for determining the indices of fluffiness of woven fabrics from a computer image, which consists in bending the fabric along one of the yarn systems, obtaining an image of the bending line of the fabric with a pile, scanning this image, obtaining digital values corresponding to the brightness of the image, summing these values and comparing the obtained value with a given value, according to the invention, scanning the image of the line of inflection of the fabric with a pile is carried out in the direction In the case perpendicular to this line, the image is divided into pixels, a matrix of pixel brightness values is obtained, these values are summed over the columns of the matrix, a brightness profile is constructed in the form of a curve of a line, in its area corresponding to light pixels, the soil level of the fabric is determined by averaging the brightness values of these pixels, the background level is determined in a similar way in the area corresponding to the dark pixels, a point on the curve in the middle of the gap between the ground levels of the fabric and the background is highlighted, the pile area is determined by building through this point and the tangent to the curve of the vertical lines through points of intersection of the tangent with the fabric soil levels and background of the height of the pile is judged by the number of pixels between these lines, and the density of the pile is measured by summing up the brightness of pixels in the area of pile.

Figure 1 shows the initial tissue sample with pile. For convenience, a negative image of the sample is shown.

Figure 2 shows the brightness profile along the line of inflection of the fabric.

Figure 3 shows an enlarged image of the pile area.

Figure 4 shows a diagram of the distribution of the number of pixels in the rows of the matrix, explaining the measurement of the height of the pile.

Figure 5 shows a distribution diagram of the total brightness of the pixels along the rows of the matrix, explaining the measurement of the density of the pile.

An example implementation of the method.

A 5 × 5 cm woven fabric sample is folded in half so that the inflection line is parallel to one of the yarn systems, for example warp. In this form, the sample is installed on the working surface of the optical scanner against the background of a contrasting substrate and scanned to obtain graphic information. At the same time, the sample is placed in such a way that the progressive scanning process occurs perpendicular to the sample bend line (Fig. 1). Scanning the sample is carried out in reflected light with a resolution of 1200 pixels per inch, and then the received graphic image of the sample is rotated on the display by a certain angle (1 ... 2 °) so that the threads of the sample base coincide with the columns of the display. This operation is necessary to eliminate the error caused by inaccurate sample location in the scanning device. Then the image of the tissue sample is divided into parts (equal to one pixel), each of which has a certain brightness in the range from 0 (corresponds to black) to 255 (corresponds to white), measure the brightness in each part and form a matrix of brightness values (hereinafter - matrix). By summing these values over the image columns, a brightness profile is constructed in the form of a curved line (Fig. 2). Then, the following sections are distinguished on this line: a section corresponding to bright pixels (with high brightness values) and a section corresponding to dark pixels (with low brightness values). Next, on the first of these sections of the curve, the soil level of the fabric is determined by averaging the brightness values of bright pixels. The background level is determined on the second of these sections of the curve by averaging the brightness values of dark pixels. Then, a point (pixel) is selected on the curve corresponding to the middle of the gap between the soil levels of the fabric and the background. Then, through the selected point, the tangent to the curve is constructed. After that, draw a vertical line (line 1) through the point of intersection of the tangent with the ground level of the fabric and a vertical line (line 2) through the point of intersection of the tangent with the background level. As a result, a pile zone is obtained, limited by line 1, the soil level of the fabric, line 2 and the background level (Fig. 3). In the future, measurements of hairiness indicators are carried out within this zone.

The pile height is judged by the number of pixels between lines 1 and 2. To do this, first determine the column numbers of the matrix corresponding to line 1 and line 2. Then, the difference between these numbers is determined, which corresponds to the height of the pile image. Recalculation of the measured value into the real value of the height of the pile is carried out by conversion through a scale factor.

The density of the pile is determined as follows. In the matrix, pixels belonging to the pile area are extracted. By summing the brightness values of these pixels, the value

where G is the value corresponding to the density of the pile;

I _ij is the current value of the pixel brightness;

n is the number of rows of the image matrix of the pile area;

k is the number of columns of the image matrix of the pile zone.

After that, determine the maximum possible total value of brightness in the pile area

- максимальное суммарное значение яркости в строках матрицы изображения зоны ворсаWhere

- the maximum total brightness value in the rows of the image matrix of the pile zone

The density of pile S _in is determined by the ratio

The proposed method allows you to additionally measure the values of the unevenness of the height and density of the pile.

The unevenness of the pile height is measured as follows. A column is selected in the matrix corresponding to the line of pile height. Then determine the average value of the brightness of the pixels of this column (threshold value I _nop ). Next, in each row of the matrix, the number of pixels m is determined, the brightness value of which exceeds I _nop (Fig. 4). Then, the obtained values are compared with the number of pixels corresponding to the height of the pile.

The non-uniformity of pile density is measured in the pile area by determining the total pixel brightness in each row of the matrix and comparing the resulting amounts with their average value (Fig. 5).

In this case, standard methods of mathematical statistics are used.

The main structural characteristics of the objects of study are shown in table 1.

Table 1 Sample No. Name of fabric Composition, % Width cm Surface density, g / m ² The number of threads per 10 cm Linear density of yarn, tex based by duck based by duck 1 Shorter Viscose 150 110 410 310 15.6 15.1 -fifty Polyester -fifty 2 Flannel Cotton 75 180 300 198 25 fifty smooth -80 dyed Viscose -20 3 Bike Cotton 90 360 293 297 25 84 harsh -100 4 Cloth Wool 152 408 230 149 88 88 -100

A comparison of the height and density of the pile was carried out in relation to the prototype.

The results of measuring the height of the pile of the proposed method were compared with the values of the height of the pile, measured using a metric ruler on the monitor screen according to an enlarged image of a tissue sample. In this case, conversion to real linear units was carried out through a scale factor. The results of experimental studies are presented in table 2.

table 2 Sample No. Pile height (mm) measured Relative indicator prototype method the proposed method non-uniformity of pile height,% prototype method the proposed method 1 0.19 0.18 - 10.14 2 0.58 0.56 - 12.04 3 0.94 0.91 - 14.23 4 2,30 2.25 - 9.76

Analysis of the measurement results for samples 1 ... 4 indicates a slight decrease in the values of the pile height in the claimed method compared to the analogue, which is explained by the reading of the pile height from the line of the supporting surface, which is more objective from the material science point of view. In the prototype, the pile height reference line is closer to the fabric ground than the reference surface line.

Verification of the implementation of the proposed method for measuring the density of the pile was carried out by comparing the results with the density values measured by the prototype (table 3).

Table 3 Sample No. Pile density (%), measured Relative indicator prototype method the proposed method uneven density of the pile,% prototype method the proposed method 1 67.23 73.18 - 13.51 2 61.72 66.47 - 16.38 3 56.34 63.14 - 17.37 4 73.92 81.76 - 11.04

Analysis of the measurement results indicates a slight increase in the values of the density of the pile in the inventive method compared to the prototype. This is due to the fact that in the claimed method, the values of pile density are measured in the pile area, and in the prototype this zone is not limited by the pile height line and covers part of the pile-free space.

Sources of information

1. Japanese application No. 53-98454, cl. D 01 H 13/32, 1978.

2. USSR copyright certificate No. 1254385, cl. G 01 N 33/36. 1984. A device for controlling the hairiness of tissue.

Claims (1)

A method for determining the fleecy indicators of woven fabrics from a computer image, which consists in bending the fabric along one of the yarn systems, obtaining an image of the bending line of the fabric with a pile, scanning the specified image, obtaining digital values corresponding to the brightness of the image, summing these values and comparing the obtained value with a given value characterized in that the scanning image of the line of inflection of the fabric with a pile is carried out in the direction perpendicular to this line, produce the image into pixels, a matrix of pixel brightness values is obtained, these values are summed over the matrix columns, a brightness profile is constructed in the form of a curve line on its portion corresponding to bright pixels, the soil level of the fabric is determined by averaging the brightness values of these pixels, the background level is determined in a similar way the area corresponding to dark pixels, a point on the curve in the middle of the gap between the ground levels of the fabric and the background is highlighted, the pile area is determined by plotting through this point a tangent to the curve and rovedeniya vertical lines through points of intersection of the tangent with the fabric soil levels and background of the height of the pile is judged by the number of pixels between these lines, and the density of the pile is measured by summing up the brightness of pixels in the area of pile.

Images