Method and computer system for dynamically measuring deformation of conveyed fabric

Abstract

The present invention provides a method for dynamically measuring the deformation amount of a fabric transported by a conveying unit, which is implemented by a computer, comprising: a step of using a shooting unit to shoot the fabric at a first moment to obtain a first image; a step of using a shooting unit to shoot the fabric after being moved by the conveying unit at a second moment to obtain a second image; a step of using a detection unit to detect a first form of a fabric tissue pattern based on the first image to obtain a first analytical image; a step of using a detection unit to detect a second form of a fabric tissue pattern based on the second image to obtain a second analytical image; a step of using a comparison unit to compare the first analytical image and the second analytical image to obtain the movement amount of the first reference point and the movement amount of the second reference point; and a step of using a calculation unit to calculate the deformation amount of the fabric based on the movement amount of the first reference point and the movement amount of the second reference point.

Description

Technical Field

[0001] The present invention generally relates to a method and system for measuring deformation of a fabric based on DIC taking into account the fabric structure. Background Art

[0002] At the fabric (cloth) manufacturing site, fabric weave is defined as design data. Fabric weave (also called fabric structure) refers to the rules of warp and weft interlacing. As representative fabric weaves, three basic fabric weaves are known: plain weave, twill weave, and satin weave. In addition, fiber terms such as "interlacing" in this specification follow the definition in JIS L0206:1999.

[0003] As methods for detecting characteristics of fabric structures, there are known methods based on image analysis in the last century (see non-patent documents 1 to 2) and methods based on the digital image correlation (DIC) method in recent years (see non-patent documents 3 to 6).

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-patent document 1: Kenichi Ohta, et al., (1996). Automatic measurement of fabric structure. Proceedings of the Society for Measurement and Automation, 32(8), 1168-1174. (Original Japanese text: Kenichi Ohta, et al., (1996). Automatic measurement of fabric structure. Proceedings of the Society for Measurement and Automation, 32(8), 1168-1174)

[0007] Non-patent document 2: Nishimatsu Toyonori. (1991). Research on automatic recognition of fabric structure. Journal of the Japanese Society of Textile Machinery, 44(6), T126-T132. (Japanese original: Nishimatsu Toyonori. (1991). Research on automatic recognition of fabric structure. Journal of the Japanese Society of Textile Machinery, 44(6), T126-T132.)

[0008] Non-patent document 3: Lomov, SV, et al., (2008). Full-field strain measurements in textile deformability studies. Composites Part A: Applied Science and Manufacturing, 39(8), 1232-1244.

[0009] Non-patent document 4: Zhu B., et al., (2007). Large deformation and slippage mechanism of plain woven composite in bias extension. Composites Part A: Applied Science and Manufacturing, 38(8), 1821-1828.

[0010] Non-patent document 5: Milani AS, et al., (2007). A method for the approximation of non-uniform fiber misalignment in textile composites using picture frame test. Composites Part A: Applied Science and Manufacturing, 38(6), 1493-1501.

[0011] Non-patent document 6: Lee W. et al., (2008). Bias-extension of woven composite fabrics. International Journal of Material Forming, 1(1), 895-898. Summary of the invention

[0012] In order to mass-produce fabric products (zippers, etc.), the fabric needs to be transported at high speed, but the fabric is not a rigid body, so it deforms dynamically during transportation. With such deformation, even if the fabric is slightly offset or tilted during the manufacturing process, it has a great impact on the product yield.

[0013] Conventionally, people have relied on visual inspection to determine whether the position of a fabric is offset or tilted, or whether the shape of a fabric used as a material before a product is completed or a fabric that is completed as a product is deformed. This is not only inefficient but also lacks accuracy.

[0014] However, on the other hand, the prior art such as non-patent documents 1 to 6 are only about the detection method of the fabric structure of the static fabric or the static fabric that is deformed after the external force is applied, and there is a problem that it cannot cope with the dynamic deformation of such high-speed transported fabric.

[0015] Moreover, the shape of the fabric supplied at the actual manufacturing site is usually not uniform. In addition, depending on the type of fabric, the interlaced points that constitute the fabric structure may not be equal. Therefore, even if the existing measurement is performed using an equal grid configuration (a method in which the reference points are automatically set to an equal grid shape) in the initial state, it is impossible to measure the linear density or orientation angle and elongation required for evaluating the fabric in the grid configuration with equal reference points. Therefore, there is a problem that the results obtained by measuring the reference points of the grid configuration are not practical. Moreover, the fabric structure also changes according to the type and state of the fiber material of the fabric, and adjustments need to be made each time to cope with the changes, so it is not practical.

[0016] In addition, in the existing methods of detecting the characteristics of static fabric structures based on images, such as those described in the above-mentioned non-patent documents 1 to 2, the regularity of the complete structure of the fabric structure is utilized. However, in the DIC method involving the prior art described in the non-patent documents 3 to 6, in order to measure dynamic deformation based on images, a random pattern (irregularity) is used to track the reference point (also called evaluation point). Therefore, in the existing DIC method, it is impossible to avoid the problem of false detection due to the regularity of the fabric structure, and it is impossible to solve the problem of reduced measurement accuracy or the inability to measure at all. That is, the above-mentioned two existing methods are considered to be opposite to each other.

[0017] The inventors of the present invention have come up with the present invention which can solve the above-mentioned problems. That is, the present invention can provide the following solutions.

[0018] Solution 1.

[0019] A method for dynamically measuring the deformation amount of a fabric conveyed by a conveying unit, which is implemented by a computer, comprises:

[0020] The step of using a photographing unit to photograph the fabric at a first moment to obtain a first image;

[0021] The step of using a photographing unit to photograph the fabric after being moved by the conveying unit at a second moment after the first moment to obtain a second image different from the first image;

[0022] The step of detecting a first form of a fabric weave pattern of the fabric based on the first image using a detection unit, and obtaining a first analysis image in which a first reference point and a second reference point are set on the first form of the fabric weave pattern;

[0023] A step of detecting a second form of a fabric weave pattern of the fabric based on the second image using a detection unit, and obtaining a second analysis image in which the first reference point and the second reference point moved by the conveying unit are determined on the second form of the fabric weave pattern;

[0024] A step of comparing the first analysis image and the second analysis image using a comparison unit to obtain a movement amount of the first reference point and a movement amount of the second reference point; and

[0025] A step of calculating the deformation amount of the fabric based on the movement amount of the first reference point and the movement amount of the second reference point using a calculation unit.

[0026] Solution 2.

[0027] The method according to scheme 1, further comprising:

[0028] When the first analysis image or the second analysis image is obtained,

[0029] The step of reading the design information of the fabric from a storage unit; and

[0030] A step of comparing at least a portion of the design weave pattern corresponding to the design information with the weave pattern of the first form or the weave pattern of the second form using a comparing unit to determine the first reference point and the second reference point.

[0031] Solution 3.

[0032] The method according to scheme 1 or 2, further comprising:

[0033] A step of using a comparison unit to compare a first distance between the first reference point and the second reference point on the first analysis image and a second distance between the first reference point and the second reference point on the second analysis image to calculate the stretch amount and stretch rate of the fabric structure of the fabric.

[0034] Solution 4.

[0035] The method according to scheme 1 or 2, further comprising:

[0036] A step of further setting a third reference point in the first analysis image using a detection unit; and

[0037] The step of calculating the linear density and the orientation angle of the fabric structure of the fabric based on the coordinates of the first reference point, the coordinates of the second reference point, and the coordinates of the third reference point using a calculation unit.

[0038] Solution 5.

[0039] The method according to claim 1 or 2, wherein the fabric is a tape for a slide fastener.

[0040] Solution 6.

[0041] A computer system for measuring the dynamic deformation of a conveyed fabric, comprising:

[0042] A conveying unit configured to convey the fabric;

[0043] Timing unit;

[0044] Storage unit;

[0045] a photographing unit configured to photograph the fabric at a time set by the timing unit to obtain an image, and store the image in the storage unit;

[0046] a detection unit configured to detect a fabric weave pattern of the fabric based on the image, obtain an analysis image in which a first reference point and a second reference point are set on the fabric weave pattern, and store the analysis image in the storage unit;

[0047] a comparing unit configured to obtain a movement amount of the first reference point and a movement amount of the second reference point by comparing a plurality of the analysis images obtained based on images captured at different times; and

[0048] The calculation unit is configured to calculate a deformation amount of the fabric based on a movement amount of the first reference point and a movement amount of the second reference point.

[0049] Solution 7.

[0050] The computer system according to claim 6, wherein:

[0051] The storage unit is configured to store the design information of the fabric.

[0052] The comparison unit is configured to compare at least a part of the design weave pattern corresponding to the design information with the weave pattern, and determine the first reference point and the second reference point.

[0053] Solution 8.

[0054] A computer system according to solution 6 or 7, wherein:

[0055] The comparison unit is configured to obtain the distance between the first reference point and the second reference point on the plurality of analysis images and compare the distances with each other, thereby calculating the stretch amount and the stretch ratio of the fabric structure of the fabric.

[0056] Solution 9.

[0057] A computer system according to solution 6 or 7, wherein:

[0058] The detection unit is configured to further set a third reference point in the analysis image.

[0059] The calculation unit is configured to calculate the linear density and the azimuth angle of the woven fabric based on the coordinates of the first reference point, the coordinates of the second reference point, and the coordinates of the third reference point.

[0060] Solution 10.

[0061] A computer system according to solution 6 or 7, wherein:

[0062] The fabric is the tape for the zipper.

[0063] Effects of the Invention

[0064] By using the method and computer system provided by the embodiments of the present invention, the following effects can be achieved: the fabric structure of the conveyed fabric can be accurately detected, and the dynamic deformation of the fabric can be measured and determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram showing an example of a device that can implement the method or system according to the embodiment of the present invention.

[0066] Figure 2 This is a diagram for explaining the outline of the method according to the embodiment of the present invention.

[0067] Figure 3 A fabric weave model representing a plain weave.

[0068] Figure 4 Indicates the solution for longitude Figure 3 Results for the correlation coefficient of the plain cloth model.

[0069] Figure 5 Indicates that the latitude line is calculated Figure 3 Results for the correlation coefficient of the plain cloth model.

[0070] Figure 6 The organization diagram and complete organization of the plain weave are shown.

[0071] Figure 7 The organization diagram and complete organization of the twill weave are shown.

[0072] Figure 8 The weave diagram and complete weave of satin weave are shown.

[0073] Fig. 9 Represents the correlation coefficient of the full weave of the plain cloth model.

[0074] Fig.10 Indicates from Fig. 9 Full weave model of mapped plain weave.

[0075] Fig.11 A graph showing the correlation coefficient of the warp yarn of the plain weave in detail.

[0076] Fig.12 A graph showing the correlation coefficient of the weft yarn of the plain weave in detail.

[0077] Fig.13 This is a diagram for explaining the definition of line density and azimuth angle.

[0078] Fig.14 This is a diagram for explaining the setting of the search range.

[0079] Fig.15 This figure shows an example of setting the search range and template size in plain weave.

[0080] Fig.16 Indicates from Fig.15 The state after a certain amount of time has passed.

[0081] Fig.17A Indicates the evaluation area for the crossing points of the twill weave where the warp threads are exposed on the surface.

[0082] Fig. 17B Indicates the evaluation area for the crossing points of the satin weave where the warp threads are exposed on the surface.

[0083] Fig.18A Indicates the evaluation area for the crossing points of the twill weave where the weft yarns are exposed on the surface.

[0084] Fig.18B Indicates the evaluation area for the crossing points of the satin weave where the weft yarns are exposed on the surface.

[0085] Fig.19 This is a diagram schematically illustrating a production process of a slide fastener.

[0086] Fig. 20 An example of a conveying device used in the manufacture of a slide fastener is shown.

[0087] Fig.21 An application example of the embodiment of the present invention in slide fastener production is shown.

[0088] Fig. 22 An application example of the embodiment of the present invention in slide fastener production is shown. DETAILED DESCRIPTION

[0089] In this specification, "woven fabric pattern" refers to a certain pattern (regularity) that can express the woven fabric structure of a fabric. The term "woven fabric pattern" can also be used to physically refer to (a part of) a fabric having the pattern. The concept of "woven fabric pattern" can include the complete structure of a fabric (such as the regularity described below). Figure 6 to Figure 8 The concept of "woven fabric pattern" may also include "interlacing points", that is, points where the warp and weft are interlaced (interlaced) on the front and back sides of the fabric (points where the warp passes under the weft or the weft passes under the warp when viewed from the surface of the fabric, such as those described below). Figure 6 More specifically, the intersection point may be a location where the width center line of the warp and the width center line of the weft intersect.

[0090] In this specification, unless otherwise specified, a noun written in the singular refers to one or more objects. For example, when written as "intersection point", it is expected to be understood that it refers to one or both of one intersection point and multiple intersection points (intersection point group) according to its context.

[0091] Figure 1 An example of an apparatus capable of implementing the method or system according to an embodiment of the present invention is schematically shown in FIG. The apparatus includes a unit for conveying the fabric 10 (feed rollers, conveyor belts, tables, and their associated sensors, torque adding devices, and control devices, etc.). Figure 1 In the example, as such a unit, the device includes a conveyor table 20 for sliding and conveying the fabric 10, and a feed roller 30 for applying tension (stretching) to the conveyed fabric 10, and the fabric 10 is conveyed in the direction of the arrow in the figure. In addition, the device may also include a stopper (positioning unit) for braking the fabric 10. In addition, in the case where the fabric 10 is a tape for a zipper (zipper tape, also called a zipper chain), the device may also include a unit for detecting a spacer portion where a meshing member (also called a chain tooth) is not formed locally, and the system may further include arbitrary devices corresponding to other types and uses of fabrics.

[0092] In addition, the device includes a photographing unit 40 (CCD camera, CMOS camera, visible light camera, infrared camera, ultraviolet camera, stereo camera, etc.) for photographing the fabric 10. In addition, the number of the photographing units 40 can also be the same as that of the fabric 10. Figure 1 The example is different and there are multiple, as long as it is a position that can appropriately shoot the fabric 10 (the fabric structure pattern it has) can be set to any position and angle. In addition, it can also further include a unit for moving or rotating the shooting unit 40 (panning), and a light source for assisting the shooting.

[0093] In addition, Figure 1 An example in which the fabric 10 is transported in a flatly extended state is drawn, but in another example, the fabric can be transported on some curved surface (cylindrical surface, etc.). For example, it can also be applied to a fabric that is sewn into a shape that surrounds a cylindrical surface. In a certain embodiment, a stereo camera or multiple cameras can be used for stereoscopic shooting to obtain a three-dimensional image of the fabric 10. In this way, a three-dimensional fabric structure pattern (three-dimensional coordinates representing the intersection points of the fabric structure) can also be obtained. That is, it is hoped that it will be understood that the "image" in this specification is not limited to a two-dimensional image. In addition, it should be noted that the "image" in this specification does not need to be in the form of an image that can be visually viewed by a person, as long as it is in the form of data that can be processed by a computer (data used to represent the image).

[0094] The photographing unit 40 photographs a certain part of the fabric 10 twice or more at different times to obtain an image (image data). The size, position, and range shape of the part to be photographed can be arbitrarily set, for example, based on the conveying acceleration of the fabric 10 (i.e., the speed or moving distance that can be predicted based on the acceleration) and the photographing time interval. In addition, when the fabric to be photographed is small, the entire fabric can also be photographed. That is, in this specification, the concept of "part" of the fabric can also refer to the "entirety" of the fabric.

[0095] The photographing unit 40 is connected to a computer device (a controller capable of performing image processing based on a field programmable gate array (FPGA), a personal computer, a portable terminal, a server, a memory, etc.) not shown in the figure via a network or the like, so that data can be stored or processed. The photographing unit 40 can start the action of a unit for conveying the fabric 10 as a trigger signal. In addition, the photographing time of the image can be set by a timing unit (not shown) and the photographing time can be associated with the image.

[0096] By causing the detection unit (which can be software, hardware or a combination of these) possessed by the computer device to process each acquired image of the fabric 10, an analysis image (analysis image data) is obtained in which two or more reference points (for DIC processing, also referred to as "measurement points") are set on the image.

[0097] Figure 2 A schematic diagram for explaining the outline of the method according to the embodiment of the present invention is also shown. As a basic principle, in an image obtained by the Nth shooting and an image obtained by the N+αth shooting (N and α are natural numbers) among two or more shootings, DIC is used to track where the reference points 1 and 2 in the Nth image move in the N+αth image.

[0098] In addition, it should be noted that the "reference point" referred to in this specification is not the reference point (pixel on the captured image) after the grid configuration used in the DIC involved in the prior art, but the "intersection point" on the captured image that can be uniquely determined based on the fabric structure. In the existing DIC that uses a metal material as a rigid body as the object, the material is made homogeneous by using the "initial state" in which no load is applied to the rigid body, so that a simple measurement using a grid configuration can be performed. However, when the fabric is transported, dynamic deformation always occurs, so it is difficult or impossible to uniquely define the "initial state". In order to solve this problem, the inventors of the present invention conceived of setting a certain shooting time point as the "initial state", and instead of using the existing reference point after the grid configuration, use the intersection point or the peak position showing the correlation coefficient above the threshold value described later as a separately set reference point, thereby completing the present invention.

[0099] For example, the regularity of the fabric structure can be used to set the point where the center line of the warp and the center line of the weft intersect (i.e., the intersection point) as a reference point. When detecting the structure diagram and complete structure of such a fabric structure, for example, image matching processing can be used. That is, a certain area including the warp and weft that constitute the fabric is set as a template, and by performing image matching on the image of the fabric, the part corresponding to the template can be identified at a high speed. This is because the warp and weft in the fabric structure each have characteristics, which are suitable for image matching.

[0100] Below, for ease of understanding, take the plain weave in a lattice as an example, the method that can be used when this setting is described. In addition, as long as those skilled in the art should understand, this method is suitably adjusted and can also be applied to other fabric tissues.

[0101] Solution 1: Example of using the vicinity of the intersection point as a template

[0102] In this example, first of all, based on the fact that the complete structure of the plain weave is composed of two warp threads and two weft threads, such as Figure 3 As shown, the longitude and latitude lines each generate a template image. Figure 3 A fabric structure model representing a plain weave. Here, an image of the fabric captured at a certain moment is defined as an "initial image". That is, any image can be set as the initial image without making the fabric in a special state (there is no need to apply external force to the fabric to align the fabric structure into a neat grid shape). Furthermore, the area containing the warp or weft of the fabric structure is set as two templates, and the initial image is subjected to image matching processing, thereby independently extracting the tissue coordinates within the evaluation range within the initial image. At this time, the position where the correlation coefficient of each of the two template images within the evaluation range is the maximum value can be set as the tissue coordinate. That is, in Figure 3 In the case of , the points that match the first template image including the vicinity of the crossing points where the warp yarns float are represented by white square points, and the points that match the second template image including the vicinity of the crossing points where the weft yarns float are represented by black square points.

[0103] When calculating the correlation coefficient, for example, the cross-correlation coefficient of the following formula (1) can be used.

[0104]

[0105] From the viewpoint of improving the production efficiency of the fabric, it is preferred that the calculation time and calculation resources required for calculating the correlation coefficient be small, and for example, the above-mentioned formula (1) with a small amount of calculation can be used.

[0106] for Figure 3 The plain fabric model shown in FIG. 1 shows the correlation coefficient obtained by using formula (1). Figure 4 , for the latitude lines shown in Figure 5 . It can be seen that the correlation coefficient includes the template position and shows multiple peaks. If in a certain part of the fabric (evaluation range, in Figure 4 and Figure 5 The coordinates of the peak are set as the center coordinates of the intersection point (hereinafter also referred to as "intersection point coordinates"), and then the Figure 3 The coordinates of the intersections of the white square points (longitude) and the black square points (latitude) are mapped exactly as shown.

[0107] Second solution: Example of setting the complete organization as a template

[0108] This example uses the fact that fabrics are generally formed based on the recurrence of complete weaves. For each of the three primary weaves, Figure 6 to Figure 8 An overview of a fabric (lower right), a corresponding weave diagram (above), and an example of a complete weave that can be extracted from it (lower left) are shown. That is, in a plain weave, a pattern consisting of two warps and two wefts is a complete weave. A complete weave of a twill weave is a pattern consisting of more than three warps and more than three wefts. A complete weave of a satin weave is a pattern consisting of more than five warps and more than five wefts. In addition, in this example, for ease of understanding, the fabric weave is drawn in a lattice shape, but it should be noted that the fabric weave to which the present invention can be applied may not be in a lattice shape.

[0109] In addition, Figure 6In the summary (lower right), arrows are used to indicate the points where the warp and weft threads are switched on the front and back sides of the fabric (the points where the warp threads pass under the weft threads or the weft threads pass under the warp threads when viewed from the surface of the fabric). Figure 7 , Figure 8 The same considerations are obviously also taken into account in the summary.

[0110] The above complete organization can be set as a template. Figure 6 For example, for the image of the plain weave fabric, the correlation coefficient when the perfect weave is used as a template is obtained using the above formula (1), and the result is Fig. 9 If Fig. 9 The coordinates of the peak values ​​shown in the figure are mapped to Fig.10 Then, the coordinates of each tissue in the complete tissue can be further allocated, and the results of repeated coordinate averaging processing can be mapped. The detected longitude is a white square point, and the latitude is a black square point. Even with this method, the tissue coordinates can be measured well.

[0111] Fig.11 and Fig.12 A graph showing the correlation coefficients of the warp and weft of a plain weave in enlarged form, respectively. In this graph, the portion showing a peak value where the correlation coefficient is greater than a certain threshold value corresponds to the above-mentioned tissue coordinates.

[0112] When setting the above-mentioned template, the design information of the fabric may also be referred to.

[0113] When the peak coordinates of the correlation coefficient and the fabric coordinates are consistent as described above, if DIC is used directly to track the reference point by detecting the peak of the correlation coefficient, there is a high possibility that the adjacent fabrics will be misdetected. In view of the problem of the prior art, in the present invention, the evaluation range can be automatically determined based on the line distance and azimuth calculated based on the pre-measured fabric coordinates so that the peak of the correlation coefficient is a single one.

[0114] Therefore, in the present invention, by photographing a certain part of the fabric during transportation twice or more (i.e., obtaining two or more fabric weave patterns), and applying DIC, the deformation of the fabric during transportation can be dynamically measured. The interval of the photographing time also depends on the acceleration of the intersection point including the deformation of the fabric during transportation, and determines the maximum photographing time interval (i.e., frame rate) that can be measured, but the optimal photographing time interval (photographing speed) can be set according to the accuracy of the dynamic deformation to be evaluated. Generally speaking, high-precision measurement can be performed when the photographing time interval is short, for example, it can be in seconds, milliseconds, microseconds, or units below.

[0115] By using at least an image of the fabric at a first moment (a so-called "analysis image" in which a first reference point and a second reference point are set on a fabric weave pattern) and an analysis image at a second moment, the deformation amount of the fabric can be calculated based on the movement of the two reference points. In this calculation, a plurality of analysis images can be compared (for example, using software). In addition, by further comparing the distance between the first reference point and the second reference point on the first analysis image and the distance between the first reference point and the second reference point on the second analysis image, the stretch rate and stretch amount of the fabric can be measured and evaluated.

[0116] In addition, by setting three or more reference points and measuring the distances and changes in the positional relationship between them, the linear density of the fabric and the distortion (ie, azimuth) of the fabric structure can be measured and evaluated.

[0117] Here, refer to Fig.13 , the definition of line density and azimuth is explained. The intersection points on the warp (dark gray) (indicated by the highlighted circular and square points) and the intersection points on the weft (light gray) (indicated by the black circular points) are set respectively. Based on the straight lines connecting the intersection points, the azimuth angles θ [degree] of the warp and weft can be obtained. In addition, by dividing the deformed distance (Deformed length) by the initial distance between the intersection points (Initial length), the elongation λ of the warp and weft can be obtained respectively. warp , weft [mm / mm]. Furthermore, the linear density D of the warp and weft can also be calculated. warp , D weft [1 / mm].

[0118] DIC Setting Example

[0119] Hereinafter, a specific example in which DIC is applied to a plain weave model will be described. Figure 14 to Figure 18 is a diagram showing the search range, template (or subset), and reference point of the parameters required for DIC according to the present invention on a plain weave model. Fig.14 2 is a diagram used for this description. In this example, as the basic setting of DIC, an initial image is referred to as a template, and tracking is used to change the center coordinates of the search range by displacement (from the last time of continuous imaging).

[0120] exist Fig.14 In the example, the tissue coordinates in the “Nth image taken” are set as the reference point P. n Indicated by white circles. Here, E is the length of one side when the evaluation range is set to a square [pixel]. Let the displacement vector of the reference point generated from the n-1th image to the nth image be u n [pixel], acceleration vector is a n [pixel / s 2 ], and assume that the frame rate of image capture is F[fps], and use the following formula (2) to calculate it.

[0121]

[0122] Therefore, the position vector P of the reference point in the nth image is n It is represented by the following formula (3).

[0123]

[0124] Therefore, the center coordinates C of the evaluation area n Tracking is performed by sequentially updating the following formula (4).

[0125] C n =P n-1 +u n-1 (4)

[0126] Next, we will discuss how to make the reference point P in the nth image n Conditions for the frame rate F to be contained within the evaluation region. Consider a circle with a radius of E / 2 inscribed in the evaluation region with a side length of E, as shown in equation (7) described later, for making the reference point P n The condition of the following formula (5) is contained inside the circle.

[0127]

[0128] Let the maximum acceleration of the assumed reference point be a max By rewriting equation (5), we get the following equation (6), which can calculate the required minimum frame rate F.

[0129]

[0130] In addition, Fig.15 It is shown in FIG. 1 that in the “initial image”, the interlace point as the reference point is set to P, and the nearest interlace point among the adjacent interlace points of the same type of lines is set to Q, so that the adjacent interlace points of the same type within a circle with the distance PQ between the interlace points as the radius r is 1 point. In addition, the reference point P is set to the 0th line, the number of longitude lines to point Q is p, the number of latitude lines is q, and the interval between longitude lines is S. warp , the latitude interval is S weft [pixel], let the azimuth of the longitude and latitude be θ [degree].

[0131] The size E of the evaluation range can be calculated by the following formula (7).

[0132]

[0133] The circle with a radius of r / 2 centered at the reference point P becomes a region that can prevent erroneous detection of intersection points of other similar lines and maximize the detection range of the reference point P.

[0134] exist Fig.15 In the plain weave shown, there is one warp and one weft, so p=q=1.

[0135] The size of the template (subset) is larger than the circumscribed Fig.15 The circle with a radius of r / 2 shown in FIG. 1 is larger than a square whose side length is T [pixel]. Thus, the feature quantity of the line that becomes the intersection point is included in the template image. T can be calculated by the following formula (8).

[0136]

[0137] In addition, the search range L [pixel] can be calculated according to the following formula (9) based on the template range and the evaluation range.

[0138] L=E+T-1 (9)

[0139] Based on the calculation results, the template range Subset range set for the reference point of the "initial image" is also Fig.15 Shown in.

[0140] Next, in Fig.16 In the second image after a certain time, the reference point P in the initial image will be 2 The reference points obtained by searching for the center of the search range are shown as square points.

[0141] In addition, for twill and satin weaves with different fabric structures, Fig.17A , Fig. 17B The evaluation areas for the interlaced points where the warp threads of the p=q=1 twill weave (2 / 1 twill weave) and the p=1, q=2 satin weave are exposed on the surface are shown. That is, the evaluation area of ​​the p=1, q=2 satin weave is larger than that of the p=q=1 plain weave and twill weave.

[0142] in addition, Fig.18A , Fig.18B The evaluation area and template range are shown for the interlaced points of the weft exposed on the surface of the twill and satin weaves, respectively. As shown in Figure 18, it can be seen that: since the feature values ​​of the interlaced points of the same kind of lines satisfying formula (8) are included, the same kind of interlaced points with similar feature values ​​are located on a circle with a radius of r, and other interlaced points will not be misdetected by using the evaluation area satisfying formula (7). In other words, it can be seen that the evaluation area and template image derived according to formulas (7) and (8) based on the interlaced points of the warp exposed on the surface can also be applied to the interlaced points of the weft exposed on the surface. In addition, the above shows an example in which the weft floats more, but the interlaced points of the weft floating can be used in the organization in which the warp floats more.

[0143] The above-described system and method solutions of the present invention can be implemented in any computer system (including a processor, memory, and storage).

[0144] The embodiment of the present invention can be applied to any type of fabric, but preferably can be applied to a fabric for a zipper (zipper tape). The zipper tape is often of a relatively small size. Fig.19 As shown in FIG. 1 , it is necessary to install smaller parts such as chain teeth (engaging parts) on the zipper tape, appropriately cut the spacer (spacer), or perform various precision processing. Therefore, when manufacturing the zipper, it is necessary to use Fig. 20 The device with the spacer detection roller shown in the figure conveys the fabric under very precise control. Based on this, there is a difficulty different from large fabrics such as clothes in the manufacture of zipper tapes.

[0145] Fig.21 and Fig. 22 A specific example of an embodiment of the present invention applied to the manufacture of a slide fastener is shown. In this example, a partition is provided in the fastener tape constituting the slide fastener, and a positioning unit (stopper) included in the conveying unit is hung on the partition to adjust the conveying of the fastener tape.

[0146] First, if Fig.21As shown, reference points 1 to 4 are set at locations in the fastener tape near the positioning unit. The fastener tape, which is a plain weave (of course, other weaves may be used), is photographed twice or more by the photographing unit. Fig.21 Set as the Nth shooting, Fig. 22 In the example, it is assumed that the N+αth shooting (N and α are natural numbers), and the full structure of the plain weave is used as the template. Fig. 22 In the figure, the reference points 1' to 4' after the movement can be tracked (only the reference point 1 is shown in an enlarged manner in the figure). In addition, the number of reference points can be arbitrarily set after weighing the accuracy of the acquisition and the required calculation processing speed.

[0147] According to the embodiment of the present invention, the deformation of the fabric during the conveying process can be dynamically measured, and a very significant effect can be exerted in the manufacture of the zipper as described above. In addition, according to the records of this specification, it can also be understood that the present invention can also exert an effect in the manufacture of other fabric products, especially in the field of mass production.

Claims

1. A method for dynamically measuring the deformation amount of a fabric conveyed by a conveying unit, which is implemented by a computer, the method comprising: The step of using a photographing unit to photograph the fabric at a first moment to obtain a first image; The step of using a photographing unit to photograph the fabric after being moved by the conveying unit at a second moment after the first moment to obtain a second image different from the first image; The step of detecting a first form of a fabric weave pattern of the fabric based on the first image using a detection unit to obtain a first analysis image in which a first reference point and a second reference point are set on the first form of the fabric weave pattern; A step of detecting a second form of a fabric weave pattern of the fabric based on the second image using a detection unit, and obtaining a second analysis image in which the first reference point and the second reference point moved by the conveying unit are determined on the second form of the fabric weave pattern; A step of comparing the first analysis image and the second analysis image using a comparison unit to obtain a movement amount of the first reference point and a movement amount of the second reference point; as well as The step of calculating the deformation amount of the fabric based on the movement amount of the first reference point and the movement amount of the second reference point using a calculation unit, The first reference point and the second reference point are intersection points on the captured image that are uniquely determined according to the fabric structure.

2. The method according to claim 1, characterized in that Also includes: When the first analysis image or the second analysis image is obtained, The step of reading the design information of the fabric from a storage unit; as well as A step of comparing at least a portion of a design weave pattern corresponding to the design information with the weave pattern of the first form or the weave pattern of the second form using a comparing unit to determine the first reference point and the second reference point.

3. The method according to claim 1 or 2, characterized in that: Also includes: A step of using a comparison unit to compare a first distance between the first reference point and the second reference point on the first analysis image and a second distance between the first reference point and the second reference point on the second analysis image to calculate the stretch amount and stretch rate of the fabric structure of the fabric.

4. The method according to claim 1 or 2, characterized in that: Also includes: Using a detection unit, further setting a third reference point in the first analysis image; as well as The step of calculating the linear density and the orientation angle of the fabric structure of the fabric based on the coordinates of the first reference point, the coordinates of the second reference point, and the coordinates of the third reference point using a calculation unit.

5. The method according to claim 1 or 2, characterized in that: The fabric is the tape for the zipper.

6. A computer system for measuring the dynamic deformation of a conveyed fabric, characterized in that: include: A conveying unit configured to convey the fabric; Timing unit; Storage unit; a photographing unit configured to photograph the fabric at a time set by the timing unit to obtain an image, and store the image in the storage unit; a detection unit configured to detect a fabric weave pattern of the fabric based on the image, obtain an analysis image in which a first reference point and a second reference point are set on the fabric weave pattern, and store the analysis image in the storage unit; a comparing unit configured to obtain a movement amount of the first reference point and a movement amount of the second reference point by comparing a plurality of the analysis images obtained based on images captured at different times; as well as a calculation unit configured to calculate a deformation amount of the fabric based on a movement amount of the first reference point and a movement amount of the second reference point, The first reference point and the second reference point are intersection points on the captured image that are uniquely determined according to the fabric structure.

7. The computer system according to claim 6, characterized in that: The storage unit is configured to store the design information of the fabric. The comparison unit is configured to compare at least a part of the design weave pattern corresponding to the design information with the weave pattern, and determine the first reference point and the second reference point.

8. The computer system according to claim 6 or 7, characterized in that: The comparison unit is configured to obtain the distance between the first reference point and the second reference point on the plurality of analysis images and compare the distances with each other, thereby calculating the stretch amount and the stretch ratio of the fabric structure of the fabric.

9. The computer system according to claim 6 or 7, characterized in that: The detection unit is configured to further set a third reference point in the analysis image. The calculation unit is configured to calculate the linear density and the azimuth angle of the woven fabric based on the coordinates of the first reference point, the coordinates of the second reference point, and the coordinates of the third reference point.

10. The computer system according to claim 6 or 7, characterized in that: The fabric is the tape for the zipper.

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