A method, apparatus, computer program and computer readable medium for detecting structural defects of a wrapped yarn

Abstract

The invention relates to a method for detecting structural defects of a wrapped yarn comprising a core formed of parallel fibres, whereby the core is bound together by a fibre wrapping layer comprising wrapping fibres and wild fibres, wherein an image of the moving yarn is captured by at least one optical yarn sensor over at least a part of the yarn length, whereby the optical yarn sensor comprises at least one row of radiation sensitive elements and at least one radiation source, and the optical sensor is connected to an electronic device equipped with software, whereby the captured yarn image is processed by a digital image analysis method to obtain data about the yarn surface structure, based on the obtained data, changes of the yarn surface structure along the yarn length are evaluated, these changes of the yarn surface structure are compared to preset criteria, and if these changes of the yarn surface structure exceed these preset criteria, the relevant position of the yarn is determined as the occurrence of a yarn structural defect. Furthermore, the invention relates to an apparatus, a computer program and a computer readable medium for carrying out the method.

Description

Technical Field

[0001] The invention relates to a method for detecting structural defects in a wrapped yarn comprising a core from parallel fibers bound together by wrapper fibers and wild fibers.

[0002] The invention also relates to a device for detecting structural defects in a wrapped yarn.

[0003] Furthermore, the invention relates to a computer program (product) comprising instructions for causing an apparatus for detecting structural defects in a wrapping yarn to detect defects in the wrapping yarn during its production, processing or analysis.

[0004] Furthermore, the invention relates to a computer-readable medium having this computer program stored therein. Background Art

[0005] Yarn is produced on textile machines that are equipped with suitable equipment for converting appropriately arranged fiber strips into yarn form. Various methods and associated yarn production equipment are known. For example, yarn is produced on ring spinning machines, rotor spinning machines, and air-jet spinning machines, which have undergone considerable development, especially in recent years.

[0006] Various types of yarn are known, the properties and structure of the individual yarns being determined and influenced by the yarn production technology and the settings of the corresponding production machines.

[0007] One type of yarn produced is fasciated yarn, which comprises a core composed of a bundle of essentially parallel fibers bound together by a fiber wrapping layer. This fiber wrapping layer compresses the parallel fibers that make up the yarn core, thereby increasing friction between the individual yarn fibers in direct contact. This compression has a positive impact on overall yarn strength. The fiber wrapping layer comprises wrapper fibers and wild fibers. The wrapper fibers are helically wound around the yarn core in a relatively stable manner, with a relatively precise pitch. Indeed, the wild fibers are also helically wound around the yarn core, but these helices may have variable pitch or even variable direction, or some of the wild fibers may be incompletely wound around the yarn core. This imperfect wrapping of the wild fibers around the fasciated yarn core manifests itself in two fundamental ways within the overall yarn structure. The first manifestation of incomplete wrapping of wild fibers around the wrapping yarn core is that the wild fibers are loose between their ends, forming loops or tufts on the surface of the wrapping yarn. A second manifestation of incomplete wrapping of wild fibers around the wrapping yarn core is that the ends of the wild fibers are incompletely wrapped around the core, with these unwrapped ends of the wild fibers protruding from the core and, therefore, from the yarn itself. In the overall structure of the wrapping yarn, the ends of the wrapping fibers and, in some cases, the ends of the core fibers (i.e., the parallel fibers that form the yarn's core) protrude from the wrapping yarn core. The typical production technology for forming wrapping yarns is to produce the yarn on an air-jet spinning machine, which is highly efficient and economically profitable. Wrapping yarns formed on air-jet spinning machines are also called "air-jet yarns" and are characterized by the specific structure described above, including a core composed of parallel fibers surrounded by wrapping fibers and wild fibers, i.e., the core is surrounded by a fiber wrap.

[0008] One of the indicators used to assess yarn quality today, not just for the aforementioned wrapped yarns, is yarn hairiness. Yarn hairiness is characterized by a number of fiber ends or loops that protrude or are freely movable from the yarn or from a flat textile (woven fabric, knitted fabric, warp knitted fabric, wool). Therefore, the fundamental criterion for evaluating yarn hairiness is the number of fibers protruding perpendicular to the yarn or the measured distance of the fiber ends from the yarn.

[0009] For example, the technology for producing wrapped yarns on air-jet spinning machines also presents new problems and technical challenges that were unknown with the yarn production technologies used so far, namely ring spinning and rotor spinning. One of these relatively recent problems associated with wrapped yarns is the occasional occurrence in the wrapped yarn of locations or length sections that exhibit specific structural defects of the wrapped yarn, whereby these specific structural defects of the wrapped yarn are not noticeable at first glance in the wrapped yarn, but are objectively manifested by, for example, insufficient strength of the wrapped yarn in that specific location or section and / or an unsatisfactory appearance of the wrapped yarn in that specific location or section, whereby the manifestation of such structural defects is primarily detected only during the subsequent processing of the already produced wrapped yarn, for example, during the finishing of the wrapped yarn or during the production of textile products (weaving, knitting) from the wrapped yarn. In some cases, these structural defects of the wrapping yarn only appear in the finished product before or after dyeing, for example, in a finished fabric or knitted product, wherein these defects, which were previously invisible to the human eye, become visible to the naked eye as differences in certain locations of the fabric or knitted product. Hereinafter, these defects will be referred to as "structural defects" because their origin lies in the altered structure of a certain part of the wrapping yarn.

[0010] These structural defects of the yarn are currently undetectable by conventional methods of online wrapping yarn quality control in yarns produced, for example, on air-jet spinning machines, and are also not detectable at all by using non-contact methods of monitoring the quality of the wrapping yarn during its production. Typically, users of air-jet spinning technology (i.e., wrapping yarn producers) attempt to prevent the occurrence of these structural defects by resorting to empirical methods of setting parameters for the wrapping yarn production process, whereby it is generally not possible to check during yarn production whether the setting has been successful, but this can be checked after the yarn has been produced using feedback (e.g., through detailed yarn testing in the laboratory or by receiving responses from subsequent yarn processors), which is highly undesirable due to the high cost of laboratory testing of large quantities of wrapping yarn or the high risk of producing potentially large quantities of wrapping yarn of insufficient quality for delivery to customers.

[0011] The process of yarn formation and the influence of its specific structure on the air-jet spinning machine are comprehensively described in, for example, the doctoral thesis of Moaaz Ahmed Samy Moustafa Eldeeb entitled Different Approaches for Predicting Air Jet Spun Yarn Strength (2017), which is published in https: / / dspace.tul.cz / handle / 15240 / 26033Available at . This paper aims to describe the process of yarn formation, to investigate the influence of the selected technical parameters of the air-jet spinning machine on the yarn properties, in particular on the strength of the air-jet yarn, and, most importantly, to clarify the problem of predicting the strength of air-jet yarns. The paper involves an analysis of the structure of air-jet yarns and provides calculations of the strength of the yarn core as a bundle of parallel fibers, as well as of the strength of the rapping layer of fibers as a bundle of fibers wound in a spiral form around the yarn core. The paper also takes into account the interaction effects between the fibers in the yarn wrap and the fibers in the yarn core. In addition to the fiber parameters, yarn structure parameters are also used as input parameters of the model for calculating the theoretical yarn tenacity at short gauge lengths. As an alternative method for predicting yarn tenacity (on short length sections), a statistical model has been proposed. By using this model, the influence of the gauge length of the tensile testing machine on the tenacity of ring, rotor and air-jet spun yarns and their coefficient of variation have been studied.

[0012] One structural defect of a wrapped yarn (e.g., yarn produced on an air-jet spinning machine) is the occurrence of locations or portions of the yarn where the wrapping yarn strength is reduced, without significantly affecting the quality and / or diameter characteristics of the wrapped yarn, or the yarn hairiness parameter at these locations or portions of the wrapped yarn. However, during the production of wrapped yarns, such as on air-jet spinning machines, the quality of the wrapped yarn is assessed by monitoring the quality and / or diameter characteristics of the wrapped yarn and the monitoring of the yarn hairiness. The hairiness of the wrapped yarn is typically assessed as a statistical number obtained by measuring long yarn sections (i.e., yarn sections having a length of tens to hundreds of meters). The hairiness of the wrapped yarn is then recalculated back to a yarn length of 1 cm or 1 m. This is unsuitable for assessing yarn defects that occur only locally or only over short sections of the wrapped yarn.

[0013] In order to detect the presence of locations or sections of a wrapping yarn with reduced yarn strength without significantly affecting the quality and / or diameter characteristics of the wrapping yarn, or the yarn hairiness parameters in these locations or sections of the wrapping yarn on an air-jet spinning machine, the solution disclosed in EP 2565307 can be used. This document describes a sensor for detecting tension changes in a moving yarn on an air-jet spinning machine. The sensor comprises a contact element in the form of a pulley, through which the yarn to be measured passes. The pulley is mounted on an arm of a deformation measuring member, and changes in yarn tension caused by the local occurrence of a structural yarn defect result in changes in the deformation of the deformation measuring member. These changes in the deformation of the deformation measuring member are detected, for example, by strain gauges and evaluated to determine the presence of locations or sections of the wrapping yarn with reduced yarn strength (so-called weak yarns).

[0014] In the solution according to EP2565307, the additional mechanical effects (friction and increased yarn load) on the wrapping yarn being produced can reduce the quality of the wrapping yarn being produced, disrupt the continuity of wrapping yarn production, reduce the productivity of wrapping yarn production, or even affect the subsequent processing of the wrapping yarn. The natural presence of impurities during textile manufacturing can cause mechanical problems with the measuring device itself. Because it is a mechanical or mechatronic device, it is also relatively expensive and demanding in terms of maintenance, adjustment to different yarn types and finenesses produced, and long-term stability of the yarn production process.

[0015] Many types of yarn sensors for yarn monitoring are known. Known are contact yarn sensors, see the above-mentioned patent EP2565307, and non-contact yarn sensors.

[0016] Contact yarn sensors (i.e., sensors that require the yarn to be in direct contact with the sensor's measuring member during measurement in order to determine yarn parameters) are primarily used in laboratories and for additional yarn quality assessment, since the yarn must be stationary or move only at a limited speed during the measurement. However, as demonstrated in EP 2 565 307, contact yarn sensors are also used in yarn production on air-jet spinning machines, particularly when there are no sufficiently reliable and robust non-contact sensors to replace them.

[0017] The contactless yarn sensor is based on various physical principles, such as a capacitive sensor, an ultrasonic sensor, a charge sensor, or the contactless yarn sensor is based on an optical principle.

[0018] Different types of optical yarn sensors are described in numerous documents, such as CZ 306117, CZ 305265, EP 2827132, US 371274, EP 0627623, JP 4756411, US 6219135, US 5270787, US 5654554, US 5521395, WO 2011026249 and others.

[0019] A common disadvantage of the prior art in the field of optical yarn sensors is the inability to monitor and evaluate the occurrence of the aforementioned or mentioned structural defects, which primarily manifest themselves only during the subsequent processing of the yarn. The methods and techniques used to date for contactless evaluation of the quality of wrapping yarns, as well as quantitative (mass or diameter) parameters used to date for contactless evaluation of the quality of wrapping yarns, such as CV, IPI, yarn diameter, and yarn fineness, during the production of wrapping yarns on air-jet spinning machines, are essentially based on monitoring the quality and / or diameter characteristics and defects of the wrapping yarn. However, techniques for evaluating the hairiness of the wrapping yarn during its passage through a location or portion of the wrapping yarn having a structural defect do not generally provide any indication of an increased probability of the occurrence of a specific structural defect of the wrapping yarn in that specific location or portion of the produced wrapping yarn, or that a structural defect of the wrapping yarn actually occurs in that location.

[0020] The object of the present invention is therefore to eliminate or at least minimize the disadvantages of the background art and in particular to provide a method, a device, software and a software carrier for contactless measurement of the presence of structural defects in wrapped yarns, i.e. yarns comprising a core from parallel fibers, whereby the core is surrounded by a fiber sheath comprising wrapping fibers and wild fibers. Summary of the Invention

[0021] The objects of the present invention are achieved by a method for detecting structural defects of a wrapped yarn, the wrapped yarn comprising a core formed by parallel fibers, whereby the core is bound together by a fiber wrapping layer, the fiber wrapping layer comprising wrapped fibers and wild fibers, wherein an image of a moving yarn is captured by at least one optical sensor over at least a portion of the yarn length, whereby the optical yarn sensor comprises at least one row of radiation sensitive elements and at least one radiation source, whereby the captured yarn image is processed by a digital image analysis method to obtain data about the surface structure of the yarn, and based on the data obtained, the surface structure of the yarn along the length of the yarn is evaluated, changes in the surface structure of the yarn are compared with preset standards, and if the changes in the surface structure of the yarn exceed these preset standards, the relevant position of the yarn is determined as the location of occurrence of the yarn structural defect.

[0022] In order to simplify and speed up the method for capturing an image of a wrapping yarn and the method for performing image analysis on this wrapping yarn image for evaluating the occurrence of structural defects in the wrapping yarn, it is advantageous that, if a yarn image is captured by an optical yarn sensor along a yarn edge, the captured yarn image is processed by a digital image analysis method to obtain data about the yarn structure in an area along the yarn edge, based on the obtained data, changes in the yarn structure along the yarn edge are evaluated, these changes in the yarn structure along the yarn edge are compared with preset criteria, and if these changes in the yarn structure along the yarn edge exceed the preset criteria, the relevant yarn position is classified as a location where a yarn structural defect occurs.

[0023] It is advantageous for capturing images of the wrapped yarn if the optical yarn sensor captures an image of the yarn envelope in a region along the yarn edge, which is a limited region of the image field along the yarn edge, the image field extending both into the yarn and into a region outside the yarn, wherein this region is located along the yarn edge. Simultaneously, the image of the yarn envelope is analyzed for lateral deviations from the straight line direction of the yarn and / or an analysis of the disorder of the yarn structure is performed using digital image analysis methods.

[0024] According to one embodiment, in order to analyze the lateral deviations of the image of the wrapped yarn envelope from the straight-line direction of the yarn, changes in the orientation of the edge of the yarn image relative to the optical yarn sensor are evaluated, wherein at least one frequency range of a frequency spectrum of the yarn edge orientation is determined or set, and the frequency spectrum of the edge orientation of the yarn image is monitored and continuously evaluated in the at least one determined or set frequency range. Based on the monitored and continuously evaluated frequency spectrum of the edge orientation of the yarn image in the at least one determined or set frequency range, the waviness of the yarn surface is determined as a function of the deviations of the yarn envelope from the straight-line direction of the yarn. The current lateral deviation of the yarn envelope image from the straight line direction of the yarn is continuously statistically evaluated and compared with a reference value of the yarn surface waviness, wherein the reference value of the yarn surface waviness is formed by a long-term average of the yarn surface waviness values ​​from the same spinning unit and / or by a long-term average of the yarn surface waviness values ​​from a plurality of spinning units set to produce the same yarn, and / or the reference value of the yarn surface waviness is set as a function of current production, processing or measurement parameters at a spinning station of the air-jet spinning machine, for example, by means of a central control system of the production, processing or measurement machine. A structural defect of the yarn is detected when the current deviation of the yarn surface waviness from the reference value of the surface waviness exceeds a set determination threshold.

[0025] According to one embodiment, the above-analyzed frequency range of the spectrum of the edge orientation of the wrapping yarn is set depending on the current yarn parameters, in particular on the type of fiber material used for yarn production, the speed of yarn movement, the spinning pressure in the spinning nozzle, the fineness of the spun yarn and on the current components of the spinning unit, in particular the type of spinning nozzle.

[0026] According to one embodiment, in order to analyze disorder in the wrapping yarn structure, at least one area for monitoring the wild fiber image is determined or set over at least a portion of the yarn length that is relevant for monitoring disorder in the yarn structure, and the yarn disorder is monitored and evaluated in this area. The yarn wildness is determined as a function of the presence of irregularities in the wrapping yarn structure and / or as a function of the presence of irregularities in the wrapping yarn surface structure based on the disorder in the yarn structure. The yarn wildness is monitored and compared with a reference value for the yarn wildness, whereby the reference value for the yarn wildness is a long-term average of yarn wildness values ​​from the same spinning unit and / or a long-term average of yarn wildness values ​​from a plurality of spinning units configured to produce the same yarn and / or the reference value for the yarn wildness is set based on current production, processing or measurement parameters of a production, processing or measurement machine, and a structural defect of the yarn is detected when a deviation of the current yarn wildness from the reference yarn wildness exceeds a set determination threshold.

[0027] It is advantageous to set the area for monitoring the wild fiber image over at least a portion of the wrapped yarn length depending on the current yarn parameters, in particular on the type of fiber material used for yarn production, the speed of the yarn movement, the spinning pressure in the spinning nozzle, the fineness of the spun yarn and on the current components of the spinning unit, in particular the type of spinning nozzle.

[0028] In order to increase the accuracy and reliability of detecting structural defects of the wrapped yarn, an analysis of the lateral deviations of the image of the yarn envelope from the linear direction of the yarn and an analysis of disorders in the yarn structure are performed simultaneously.

[0029] In order to complexly determine wrapping yarn parameters while capturing yarn images in order to detect structural defects of the yarn, the optical sensor of yarn quality senses at least one yarn diameter parameter, in particular the yarn diameter.

[0030] The principle of the device for detecting structural defects in a wrapped yarn (wherein the device comprises at least one optical yarn sensor having at least one row of radiation-sensitive elements and further comprises at least one radiation source) is that the device has means adapted to carry out the method for detecting structural defects in a wrapped yarn according to the method described above.

[0031] From the perspective of efficient use of the working devices of the production or processing or measuring machine, it is advantageous if the optical yarn sensor is formed by an optical sensor of the yarn quality.

[0032] In order to ensure the computing and control performance of the device, it is advantageous if the device suitable for carrying out the method for detecting structural defects of the wrapped yarn according to the above method comprises a user electronic circuit of the microprocessor or gate array or ASIC type with a memory, or a combination of at least two of these elements.

[0033] The principle of the computer program (product) is that it comprises instructions causing the apparatus according to the preceding paragraph to perform the steps of the method of detecting structural defects of a wrapped yarn according to the preceding paragraph.

[0034] The principle of a computer readable medium for the present invention is that it has a computer program stored therein, the program comprising instructions for causing an apparatus according to the preceding paragraph to perform the steps of the method for detecting structural defects of a wrapping yarn apparatus according to the preceding paragraph.

[0035] The present invention is based on the fact that the occurrence of structural defects in a wrapped yarn, i.e. a yarn comprising a core formed by parallel fibers, whereby the core is bound together by a fiber wrapping consisting of wrapped fibers and wild fibers, can also be detected by an optical yarn sensor, which optical yarn sensor processes in detail the data obtained describing the visual characteristics or changes in visual characteristics of the structure of the wrapped yarn, in particular the surface structure of the wrapped yarn, using a special method, whereby, based on the characteristic changes in the yarn structure or the yarn surface structure captured by the optical sensor, it is possible to determine such changes in the yarn structure, or more specifically such changes in the yarn surface structure, based on these changes it is possible to determine a wrapping yarn position or a wrapping yarn portion that falls into the category of positions or portions of the wrapping yarn on which structural yarn defects, i.e. so-called processing yarn defects, are exhibited during subsequent yarn processing after the yarn production itself, i.e. in the processing stage of yarn use.

[0036] Therefore, the method according to the present invention does not detect yarn defects that affect the yarn quality described by conventional yarn quality parameters, such as the presence of thin and thick areas, hairiness, etc., but rather it only detects defects that appear in short sections of the wrapped yarn due to their specific characteristics or behavior during the subsequent processing of the yarn, for example, during or after the production of a woven or knitted fabric, when these previously hidden defects appear as optical differences in certain locations or areas of this woven or knitted fabric, for example due to different colors of these previously indistinguishable yarn locations or areas after dyeing, or due to different light reflections from these previously indistinguishable yarn locations or areas, etc. It should be noted that such yarn locations or sections with structural defects do not exhibit the quality defects, yarn diameter defects, or yarn hairiness defects that are usually monitored, and therefore, these locations with structural yarn defects generally have reduced axial strength, but even this reduced axial strength is still sufficient for yarn production and for the subsequent processing of such yarns. However, it should also be noted that if the fiber wrapping is unstable, uneven, etc., the yarn core is not sufficiently compressed. As a result, the radial strength of the yarn decreases, which in turn leads to faster wear of the yarn, which is a sign of a structural yarn defect. The radial strength of the yarn is evaluated, for example, by a rolling test. Naturally, optical yarn sensors cannot monitor yarn strength during the production, processing, or analysis of the wrapped yarn, or they cannot monitor changes in yarn tension during the production, processing, or analysis of the wrapped yarn.

[0037] The solution according to the invention thus operates on the fact that the presence of a location or portion of a yarn with a structural yarn defect manifests itself as a localized and temporary change in the structure and characteristics of the wrapping yarn, which, during the subsequent processing of the yarn into a product (fabric), during which the aforementioned portion is mixed with yarn without the structural defect, results in a visible difference in the product. It should be noted that this visible difference is not caused by a difference in yarn strength, but rather by a difference in the structure and characteristics of the wrapping yarn, which replaces the structural defect of the wrapping yarn.

[0038] It should be added that, in principle, the optical monitoring and evaluation of the locations or portions of yarns with structural defects according to the present invention does not limit other monitoring processes and evaluation of yarn quality, performed by optical or other methods, such as monitoring yarn quality from the perspective of the presence of mass or diameter defects in the yarn or from the perspective of yarn hairiness. On the contrary, it can be said that the optical monitoring of yarns and the evaluation of the presence of locations or portions of yarns with structural defects, which is the subject of the present invention, brings the quality evaluation of wrapped yarns to a completely new level, wherein the evaluation of wrapped yarns is much more detailed because it focuses on the presence of rapid changes in the yarn structure or rapid changes in the yarn surface structure, which are currently not utilized in any way during yarn production or in the subsequent processing or analysis of the wrapped yarn.

[0039] Therefore, the subject of a detailed analysis of the characteristics of the wrapping yarn according to the present invention is rapid changes in the wrapping yarn structure, in particular rapid changes in the wrapping yarn surface structure, in particular changes in the wrapping of the yarn core by the wrapping fibers and / or by wild fibers, as well as the presence of slack portions or free ends of wild fibers, free ends of other yarn-forming fibers and possible yarn core slack due to insufficient wrapping, either directly on the surface of the wrapping yarn and / or in a very limited area outside (above) the surface of the wrapping yarn. For the purposes of the present invention, these rapid changes in the wrapping yarn surface structure are well characterized as changes in the waviness of the yarn surface and / or changes in the wildness (disorder) of the yarn surface, according to which such locations or portions of the wrapping yarn can be classified as locations or portions having structural defects of the wrapping yarn.

[0040] As such, optical yarn sensors are generally known in principle, particularly for assessing yarn quality, such as yarn diameter defects (and, if appropriate, yarn hairiness). These sensors can be used in the present invention as long as they allow sufficiently detailed and rapid acquisition of yarn images and processing of the acquired image data regarding visual characteristics of the wrapping yarn structure, or more specifically, visual characteristics of the wrapping yarn surface structure. Preferably, a sensor is used whose one or more sensing elements provide sufficient resolution to capture detailed yarn images for assessing the wrapping yarn surface structure. Such a sensing element (or elements) can be, for example, a single row or even multiple rows of optical sensing elements with a sufficient density of radiation-sensitive elements, arranged adjacent to each other in rows transverse to the yarn travel path, such as at the spinning stations of an air-jet spinning machine or at the workstations of a winding machine. Another advantage of the solution according to the present invention is that the optical yarn sensor acquires image data regarding the visual characteristics of the structure of the wrapping yarn, or regarding the visual characteristics of the surface structure of the wrapping yarn, without any additional mechanical components acting on the wrapping yarn. Therefore, the wrapping yarn is not subjected to any additional stresses. This allows for high production, processing, or measurement speeds without compromising the quality of the produced, processed, or measured wrapping yarn. Furthermore, any changes or adjustments to the settings for optically monitoring and evaluating structural yarn defects in different types of wrapping yarn can be performed simply by modifying software and changing the relevant parameters of the evaluation algorithm within the device according to the present invention, which is fast and relatively inexpensive. Another advantage is that the optical yarn sensor is universally applicable to both wrapping yarn sensing according to the present invention and to previously used optical sensing and yarn quality evaluation methods based on principles such as diameter yarn defects, yarn hairiness, etc. This is economically advantageous and simplifies the construction of workstations, such as the spinning unit of an air-jet spinning machine or a workstation of a winding machine. However, it should be noted that the present invention can also be implemented as a solution independent of existing methods for evaluating wrapping yarn quality.

[0041] From the perspective of wrapped yarn image processing, digital image analysis, such as a specific image analysis program (based on, but not limited to, this specific image analysis program), is used to represent the signal in the frequency domain, representing the output signal of an optical yarn image sensor, where this signal is interpreted as the sum of a series of appropriately selected periodic functions. This approach differs from standard methods, in which the output signal of an optical yarn image sensor is interpreted as a function of time. In practice, the use of trigonometric functions (i.e., sine and cosine functions) has proven most effective. To this end, the given output signal is decomposed into its harmonic components (1, 2, 3, ...) using, for example, a Fourier transform, and a spectrum of the given signal is created. The output of this processing is a complex number, since each frequency has its own amplitude and phase. In this case, an amplitude and phase spectrum are typically used. Information about a given signal is carried by both spectra; one without the other is incomplete. A spectrum is a representation of certain signal frequencies in terms of their repetition, frequency intensity, or amplitude. An amplitude spectrum is the frequency dependence of the amplitude of the measured quantity. From the frequency spectrum, it is possible to see the frequencies of simple oscillatory motions that have the greatest influence on the resulting complex process. In our case, it is also possible to use the so-called power spectrum, which in layman's terms means "what power do the frequency components of the signal have?" This can be simplified to the square of the amplitude spectrum. However, it is necessary to take into account the fact that the power spectrum indicates the energy-to-signal ratio, and to some extent, this is an important difference from the classical methods using the frequency domain.

[0042] In our case, it is also possible to determine, for example, based on production parameters of a spinning machine, winding machine, etc., such as spinning speed, wrapping yarn movement speed, etc., the frequency range of the spectrum that is important for the purposes of the present invention, and to determine the "energy" of this power spectrum range. It is then possible to work with the values ​​thus determined, for example, as a criterion for determining the waviness of the yarn surface.

[0043] Another option is to use digital filters for signal processing. In this case, the input signal is processed by a digital bandpass filter, through which only signals of a specific frequency can pass to the filter output, whereby the specific frequency is set according to machine parameters or determined in an appropriate manner.

[0044] For the purposes of the present invention, the waviness of the yarn surface is understood to mean the deviation of the yarn envelope from the straight-line orientation of the yarn. The waviness of the yarn surface, or yarn waviness, is preferably determined by storing the position of the first, and possibly also the last, successively obscured radiation-sensitive element of the optical sensing element for each image of the yarn on the linear optical sensing element, thereby detecting the current position of the yarn edge and, therefore, monitoring the yarn envelope, which is further analyzed by the method according to the present invention. Furthermore, for each yarn image on the linear optical sensing element, fibers protruding from the yarn core are first filtered out, and then the position of the obscured radiation-sensitive element of the optical sensor of at least one edge of the yarn core is determined. The position of the yarn edge is stored, and the envelope of the yarn core is monitored. Subsequently, the envelope of the yarn core is analyzed according to the method according to the present invention.

[0045] The term "wildness" of wrapped yarns is essentially a new qualitative parameter for wrapped yarn evaluation, distinct from the qualitative parameters used today and, consequently, from the parameter known as yarn hairiness. In principle, yarn wildness is an indicator (property) of wrapped yarns that describes and quantifies the presence of irregularities in the wrapped yarn structure, or more specifically, in the surface structure of the wrapped yarn, primarily due to irregularities in the wrapping of the fiber sheath around the yarn core and other irregularities in the yarn structure itself. Thus, yarn wildness takes into account the presence of wild fibers twisted on the yarn core, their number, the direction of fibers relaxed on the core, and the presence of untwisted free ends or other portions of wild fibers. Furthermore, the yarn wildness parameter accounts for the presence of loose yarn cores due to inadequate localized wrapping of the yarn core. Furthermore, the yarn wildness parameter considers the presence of fibers protruding from the yarn core and passing through a limited area along the core edge to the yarn hairiness evaluation area. Thus, the wildness of a wrapping yarn is a property that describes the degree of disorder in the yarn structure or the degree of disorder in the yarn structure over a short length portion of the wrapping yarn.

[0046] A method for monitoring and identifying a wrapped yarn structure comprises monitoring and identifying the untwisted free ends of wild fibers in a narrow band along the edge of a yarn core when an optical yarn sensor captures a yarn image, whether the yarn image is obtained by the yarn casting its shadow on at least one row of radiation-sensitive elements of the optical sensing element, or the yarn image is obtained by reflection of radiation from the yarn and the reflected radiation incident on at least one row of radiation-sensitive elements of the optical sensing element. Based on the captured yarn image, the position and extent (size, thickness, diameter) of the yarn core are determined, and all objects recorded in the set narrow band of the image along the yarn core thus identified are considered to fall within the assessment of the wildness of the wrapped yarn.

[0047] Another method of monitoring and identifying wrapped yarn structures is to use image analysis of the yarn image with the ability to identify the location and extent (size, thickness, diameter) of: the yarn core, the untwisted free ends of wild fibers, as well as the wild fibers wrapped around the yarn core, the free fiber ends of the wrapped fibers, the free ends of fibers protruding from the yarn core, etc., i.e., irregularities located on the yarn surface.

[0048] Subsequently, for example, the number of radiation-sensitive elements of the sensing element that are activated (either blocked or illuminated by radiation reflected from the yarn) and thus located outside the identified image of the yarn core in a defined narrow band along the identified yarn core is summed. Alternatively, these irregularities can be monitored within the captured yarn image along the yarn core in a defined narrow band (e.g. even across several rows of sensitive elements of the sensor), including image analysis of the entire yarn image, which makes it possible to identify irregularities in the structure of the wrapping yarn, etc., along the entire width of the captured wrapping yarn image.

[0049] As already mentioned above, it is also possible to obtain image data about the wrapping yarn, or more specifically, image data about the surface structure of the wrapping yarn, by means of an image analysis method of a yarn image, from which data describing visual features of the wrapping yarn, or more specifically, describing visual features of the surface structure of the wrapping yarn, are determined by means of an image analysis method, and these data are used according to the method of the invention to detect positions or parts of the wrapping yarn that have structural yarn defects. This image analysis is possible, for example, by means of convolution methods, filtering methods, detection of edges or objects in the image, etc., for example, according to the authors Klima, M., Bernas, M., Hozman, J., , P.’s publications: (Image Information Processing), a textbook of CVUT, Praha 1996, and then based on the publication “Introduction to Digital Image Processing” available at http: / / teachme.free.fr / lmageProc.pdf, , and according to the author

[0050] Publications: (Image Data Analysis Methods) (5 / 2002) and others. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The invention is schematically shown in the accompanying drawings, in which:

[0052] Figure 1 shows the arrangement of an air-jet spinning machine and one of its spinning stations,

[0053] Figure 2 shows details of the general arrangement of the apparatus according to the invention,

[0054] Figure 2a shows details of the arrangement of one embodiment of the device according to the invention,

[0055] Figure 2b shows details of the arrangement of a second embodiment of the device according to the invention,

[0056] Figure 3 shows an example of the structure of the wrapping yarn and its parts according to the present invention,

[0057] Figure 4 shows an example of a structure of a wrapping yarn with structural defects,

[0058] Figure 5 shows a rough flow chart of the evaluation of structural defects of a wrapped yarn according to the present invention,

[0059] Figure 5a shows a detailed flow chart of the evaluation of structural defects of the wrapped yarn according to the present invention,

[0060] Figure 6 shows the spectrum of the yarn surface edge orientation (changes in the edge orientation) in the frequency domain having a determined or set frequency range, which is important for monitoring the spectrum of the yarn surface edge orientation (changes in the edge orientation);

[0061] Figure 7 shows a captured image of an actual wrapped yarn subjected to structural defect detection according to the present invention;

[0062] Figure 8a An image from edge detection of an actual wrapped yarn used for the purpose of the present invention is shown, the image being obtained, for example, by Figure 2a The arrangement of sensors captures,

[0063] Figure 8b An image from the inspection of the core, wrapping fibers and wild fibers of an actual wrapped yarn used for the purpose of the present invention is shown, the image being for example obtained by Figure 2b The arrangement of sensors captures,

[0064] Figure 8c An image captured from the inspection of the yarn structure for the purpose of the present invention is shown. Figure 8a and Figure 8b A combination of captured images is created. DETAILED DESCRIPTION

[0065] Reference will be made to the spinning station on the air-jet spinning machine. 1 Production of wrapped yarn 3 During the detection of wrapped yarn 3However, the present invention is applicable to many other textile machines, in particular winding machines and machines for measuring the structural defects of wrapped yarns. 3 Therefore, the present invention is not only suitable for wrapping yarn 3 Online non-contact detection of wrapped yarn during production 3 structural defects, and is suitable for wrapping yarn 3 Subsequent processing stages, e.g. when winding the wrapping yarn 3 When wrapping yarn 3 When processed into subsequent products, etc.

[0066] When only the term "yarn" is used hereinafter, it will mean "wrapping yarn 3 ”, which comprises a core formed of parallel fibers 30 ,core 30 Tied together with a fiber wrap comprising a wrapping fiber 31 and wild fiber 32 .

[0067] For detecting wrapped yarn 3 The structural defect method of the wrapped yarn 3 comprising a core formed of parallel fibers 30 ,core 30 Tied together with a fiber wrap comprising a wrapping fiber 31 and wild fiber 32 , this method uses the fact that yarn 3 Image courtesy of Yarn 3 At least one optical sensor 6 In yarn 3 The optical yarn sensor captures at least a portion of the yarn length. 6 Include at least one line 610 Radiation-sensitive components 6100 and at least one radiation source 62 , and the optical sensor 6 Connect to electronic device equipped with software 7 Yarn processing by digital image analysis 3 Capture images to obtain information about the yarn 3 Surface structure data and, based on these obtained data, evaluate the 3 Length of yarn 3 The surface structure changes. 3 These changes in the surface structure are compared with a preset standard and if the yarn 3 If these changes in the surface structure exceed a preset standard, the relevant position of the yarn is determined to be a wrapping yarn. 3 Structural defectsV The location of appearance.

[0068] Preferably, the optical sensor of the yarn 6 Along the yarn 3 Edge H Capture wrap yarn 3 The captured yarn is processed by digital image analysis method 3 to obtain information about the yarn along the edge of the yarn 3 structure data and, based on the data obtained, evaluate the 3 The edge of the yarn structure changes. 3 of These changes in the structure of the yarn along the edge are compared with a preset standard and if the yarn along the edge of the yarn 3 If these changes in the surface structure exceed a preset standard, the relevant position of the yarn is determined to be a wrapping yarn. 3 Structural defects V The location where it appears.

[0069] Advantageously, the optical sensor of the yarn 6 Along the yarn 3 The edge of the yarn is captured and the yarn is analyzed by digital image analysis. 3 The image of the envelope is analyzed for lateral deviations from the straight direction of the yarn, and / or an analysis of the disorder of the yarn structure is performed.

[0070] To analyze the yarn 3 Enveloping images and yarns 3 Transverse deviation of the yarn in the straight line direction during yarn movement, e.g. during yarn production or yarn winding, to evaluate the edges of the yarn image H The position change of the optical sensor 6 relative to the yarn is continuously monitored and evaluated during the yarn movement. 3 Edge H A frequency range of the spectrum of the azimuth O and in at least one frequency range determined or set 0 Yarn 3 The edge of the image H The spectrum of the direction E Based on at least one determined frequency range O Yarn 3 Edges of the image H Monitoring and continuous assessment of the spectrum of the direction E , as yarn 3 Envelope and Yarn 3 The function of the deviation of the straight direction of the yarn is determined 3 Surface waviness KYarn 3 Enveloping images and yarns 3 The current lateral deviation from the straight line direction is continuously evaluated statistically and compared with the waviness of the yarn surface. K Reference value Kref For comparison, the yarn 3 Surface waviness K Reference value Kref Formed from the same unit 1 The waviness of the yarn 3 surface K The long-term average of the values ​​and / or the formation of 1 The waviness of the yarn 3 surface K The long-term average value of the multiple units 1 are configured to produce, process or measure the same yarn 3 , and / or yarn 3 Surface waviness K Reference value Kref It is set according to the current production or processing or measurement parameters of the production or processing or measurement machine, and when the yarn 3 The surface waviness K relative to the yarn 3 The waviness K Reference value Kref Current deviation When the set judgment threshold is exceeded, the yarn structural defects are detected V .

[0071] According to one embodiment, depending on the current yarn parameters 3 , especially depending on the type of fiber material used for yarn production 3 , yarn movement 3 Speed, spinning nozzle 20 The spinning pressure and the yarn spun 3 The fineness depends on the spinning unit 2 Current components, especially the spinning nozzles 20 Set the wrapping yarn type, etc. 3 Edge H The spectrum of the direction E The range of frequencies analyzed.

[0072] To analyze the wrapped yarn 3 The structure is disordered, determines or sets at least one for monitoring the yarn length 3 Wild fiber on at least part of 32 Frequency domain of the image OL , the domain OL is important for monitoring yarn structure 3 The disorder in is important, and in this domain OL Monitoring and evaluation of wrapped yarns3 The disorder of the structure. According to the yarn 3 Disorder in the structure, as a function of the presence of irregularities in the wrapping yarn structure and / or as a function of the wrapping yarn 3 The presence of irregularities in the surface structure of the yarn is determined as a function of 3 Wildness W . Monitoring Yarn 3 wildness W and mix it with yarn 3 wildness W Reference value Wref For comparison, the yarn 3 wildness W Reference value Wref Formed from the same unit 1 Yarn Wildness W's Long-term average of values, and / or from multiple units set up to produce the same yarn 1 Yarn Wildness W The long-term average of the value of, and / or yarn 3 wildness W Reference value Wref It is set according to the current production or processing or measurement parameters of the production or processing or measurement machine, and is adjusted when the current yarn wildness W is equal to the yarn wildness W Deviation of the reference value Wref When the set judgment threshold is exceeded, the yarn structural defects are detected V .

[0073] The following situations are advantageous, depending on the current yarn parameters 3 , especially depending on the 3 Fiber materials 11 、 14 Type of yarn 3 Movement speed, spinning nozzle 20 The spinning pressure and the yarn spun 3 The fineness depends on the spinning unit 2 Current components, especially the spinning nozzles 20 Type, etc., set to monitor the wrapped yarn 3 Wild fibers along at least part of their length 32 The domain of the image OL .

[0074] Preferably, the wrapping yarn is performed simultaneously 3 Enveloping images and yarns 3 Analysis of the lateral deviation of the straight line direction and the yarn 3 Analysis of disorder in structures to achieve more accurate results and increase yarn3 Structural defects in V reliability of the detection.

[0075] Workstations for efficient use of machines 1 Device at the yarn 3 At least one average parameter of a yarn, in particular 3 Diameter , by optical sensor of yarn quality 3 6 Sensing, the optical sensor 6 At the same time, the image of the wrapping yarn 3 is captured to detect structural defects of the yarn V .

[0076] For detecting wrapped yarn 3 The structural defect of the device has a yarn 3 At least one optical sensor 6 , the optical sensor 6 Has at least one row 610 Radiation-sensitive components 6100 The device further comprises at least one radiation source 62 , and is also provided to be suitable for performing, for example, the production of wrapped yarns on an air-jet spinning machine 3 During or while winding previously produced yarn 3 During the period, etc. 3 Structural defects V According to a preferred embodiment, the optical yarn sensor 6 The optical sensor is formed by the yarn quality. It is suitable for performing optical detection of wrapped yarn. 3 Structural defects V Device or electronic device for method 7 It comprises: a user electronic circuit of the microprocessor or gate array or ASIC type with memory, or a combination of at least two of these elements.

[0077] The computer program (product) for implementing the present invention includes: 3 Instructions for an apparatus for optically detecting structural defects in wrapped yarn 3 The computer program is preferably stored on a computer readable medium.

[0078] The following description focuses on an example of describing an arrangement of an air-jet spinning machine for producing a wrapped yarn comprising a core formed of parallel fibers. 30 , the core 30 Included wrapping fibers 31 and wild fiber 32 The fiber wrapping layer is wrapped around and focuses on describing the yarn3 Examples of image acquisition and image processing for the production of wrapped yarns on air-jet spinning machines 3 Optical inspection of yarn during 3 Structural defects V The purpose of yarn 3 Evaluation of the image. This description can also be used to process the wrapping yarn 3 or otherwise process the wrapped yarn 3 Winding machines and other textile machines, for example, special textile machines or measuring machines.

[0079] The air-jet spinning machine comprises at least one row of identical spinning stations arranged adjacent to each other. 1 Each spinning station 1 A container for the fiber material used to produce the wrapping yarn 3 is included. The container is typically composed of a fiber strip stored therein. 11 Cans 10 Spinning station 1 Further comprising a drafting device 13 , from the bobbin 10 To the drafting equipment 13 Feeding strips 11 , and the drafting equipment 13 The long strip 11 Reduced to a size suitable for feeding to the spinning nozzle 20 The formation of 14 , the spinning nozzle 20 Arranged in the spinning unit 2 In the spinning unit 2 It is a spinning station 1 part of.

[0080] Spinning unit 2 Suitable for spinning nozzles 20 Fiber formation in 14 Converted into yarn 3 , yarn 3 By arranging it at the spinning station 1 Extraction mechanism 4 Along the spinning unit 2 The direction of movement of the downstream fiber material from the spinning unit 2 Extracted from the yarn, where the fiber material is already in the yarn 3 In the form of. Spinning station 1 Further comprising a bobbin 50 Yarn on 3 Traverse and knotting equipment 5 , the device 5 Arrange on yarn 3 Extraction mechanism 4 Downstream of the spinning station in the direction of fiber material movement 1and adapted to traverse the yarn across the width of the rotating bobbin 50 3 And the yarn 3 Winding onto rotating bobbin 50 superior.

[0081] yarn 3 At least one optical sensor 6 Arranged in the spinning unit 2 Yarn 3 Export 21 With yarn 3 To the spool 50 Traverse and winding equipment on 5 Between. Yarn 3 Optical sensor 6 Suitable for spinning stations on air-jet spinning machines 1 Yarn production 3 During execution of yarn 3 Optical sensing, i.e., in the production of yarn 3 Period capture of yarn 3 Image. Optical yarn 3 sensor 6 Connect to electronic device equipped with software 7 According to the present invention, the yarn 3 Optical sensor 6 and electronic devices 7 Suitable for capturing yarn images and processing them, i.e. obtaining and processing information about the wrapped yarn 3 information of visual features, or more specifically, by optical sensors 6 The data provided on the visual characteristics of the surface structure of the wrapped yarn, either in the form of a yarn image or in the form of an output signal corresponding to some monitoring parameter, are used in the spinning station of the air-jet spinning machine. 1 Yarn testing during yarn production 3 structural defects.

[0082] Optical sensors 6 Typically includes at least one radiation source 60 , which is relative to the yarn 3 Arranged in a suitable orientation, or relative to the yarn 3 Pass through optical sensor 6 The path is arranged in the appropriate orientation. Optical sensor 6 Further comprising an optical sensing element 61 , radiation source 60 Also relative to the optical sensing element 61 Arrange appropriately.

[0083] exist Figures 1 to 2a In the exemplary embodiment shown in FIG, the radiation source60 and sensing elements 61 relative arrangement, whereby the radiation source 60 and sensing elements 61 There is a measuring slot between 62 , used in yarn 3 Sensing yarn during production 3 Period Yarn 3 Therefore, during yarn production, the yarn 3 As it is in the spinning station 1 is sensed and transmitted through the measuring slot 62 .

[0084] In another exemplary embodiment, there is a radiation source 60 , sensing element 61 and yarn 3 Another suitable mutual arrangement of the paths, i.e., in the yarn 3 The yarn is sensed during production 3 The orientation, including for example Figure 2b In the embodiment shown in FIG. 1 , there is a method for generating a radiant energy by a radiation source. 60 Launch and run from yarn 3 Reflected radiation to sense the yarn 3 The arrangement is located at the sensing element 61 In the measurement space in front, the radiation source 60 Located in yarn 3 and sensing elements 61 On the same side, or in other words, the radiation source 60 Here, from the sensing element 61 From its point of view Irradiate the yarn in the same direction as the yarn 3 .

[0085] In an exemplary embodiment not shown, the optical sensor 6 including at least one pair of radiation sources 60 , where one of the radiation sources 60 and sensing elements 61 relative arrangement, and measuring slots 62 cloth Place this radiation source 60 and sensing elements 61 Between, and other radiation sources 60 Arrange on yarn 3 and sensing elements 61 On the same side, that is, the radiation source 60 Here, from the sensing element 61 Illuminate the yarn from the same direction it is pointing towards the yarn 3 . Therefore, in principle this is Figure 2a The radiation source of the embodiment shown in 60 and Figure 2bThe combination of radiation sources of the embodiment shown in FIG. 60 This combination is advantageous because the sensing element 61 Oppositely arranged radiation sources 60 (See Figure 2a ) for the sensing element 61 Create on Yarn 3 The profile of the sensing element 61 Co-directionally arranged radiation sources 60 (See Figure 2b ) is used to sense the 3 Reflected and incident on the sensing element 61 In this case, the two radiation sources mentioned above 60 synchronized with each other so that the radiation they emit alternates rapidly, thus a sensing element 61 Ability to sense not only the yarn alternately 3 The outline, that is, the edge H , their lateral displacement, yarn 3 Structure in yarn 3 The presence and parameters of irregularities in the surface projection, such as wrapped fibers 31 , wild fiber 32 , free ends of wild fibers 320 , wild fiber 32 The slack part 321 , yarn 3 core 30 The short slack part LN , wrapping fiber 31 The protruding end 310 , yarn 3 core 30 The protruding end of the fiber 300 etc., see Figure 8a , but it can also be viewed from the sensor element 61 The side of the yarn is sensed 3 The visual appearance of the structure, i.e. the yarn 3 core 30 Encapsulated fiber 31 and wild fibers 32 Package, and package fiber 31 itself, wild fiber 32 itself, wild fiber 32 The free end 320 , wild fiber 32 The slack part 321 , yarn 3 core 30 The short slack part LN , wrapping fiber 31 The protruding end 310 , yarn 3 core30 The protruding end of the fiber 300 etc., see Figure 8b In order to process the yarn images and obtain information about the produced wrapped yarn 3 Visual data of the structure of the wrapped yarn 3 These results of image acquisition can be processed separately, see Figure 8a and Figure 8b , or it may be advantageous to combine them, see Figure 8c , and process them together.

[0086] Radiation source 60 formed by a suitable radiation emitter, such as a point or multipoint or planar emitter, etc., optionally preceded by suitable optics for optimizing the radiation direction for improved sensing of the yarn 3 For example, in Figure 2a In an embodiment, a collimating optical device is arranged in front of the point radiation emitter 600 , used to convert radiation from a source 60 The light rays pass through the measuring slot 62 Parallelization to the sensing element 61 Top quality.

[0087] Sensing element 61 Include at least one line 610 Radiation sensitive elements arranged adjacent to each other 6100 (pixels), where the row 610 Radiation-sensitive components 6100 Arranged to its length L Essentially transverse to the yarn 3 In the embodiment shown, the line 610 Radiation-sensitive components 6100 Arranged to its length L Essentially transverse to the yarn 3 Yarn during production 3 Direction of movement P , that is, transverse to the yarn 3 Yarn during production 3 path.

[0088] In an exemplary embodiment not shown, the yarn sensor 6 Includes at least two sensing elements 61 , each with at least one row 610 Radiation sensitive elements arranged adjacent to each other 6100 , whereby at least two sensing elements 61 relative to each other and also relative to the yarn path 3 Oriented in space, i.e. relative to each other and to the spinning stations on the air-jet spinning machine 1The yarn being sensed 3 Orientation, which enables the capture of the yarn 3 Multidimensional images of the yarn captured in this way 3 The results of the image are used to perform multidimensional processing, which is particularly helpful to increase the determination of yarn 3 Structural defects V The accuracy of the location or appearance of the part.

[0089] In another exemplary embodiment not shown, physically different yarns 3 The sensor is assigned to the optical yarn sensor 6 , such as yarn 3 Tension sensor, capacitive yarn sensor, yarn vibration sensor, sound yarn sensor, etc., which makes it possible to use the sensing yarn according to the present invention according to the current needs. 3 Optical principles of structural defects in yarns 3 Physically different sensing is appropriately combined.

[0090] Preferably, the optical yarn 3 sensor 6 Made of yarn 3 The optical sensor can provide information about the quality of the yarn being sensed. 3 The yarn image can be captured with the required quality and at the required speed.

[0091] Electronic device with software 7 Includes hardware components that provide computing performance and logic operations to execute software operations for processing data generated by optical sensors. 6 Captured output yarn 3 Images of the spinning stations on air-jet spinning machines 1 Yarn 3 Testing yarn during production 3 Structural defects V .

[0092] If the electronic device 7 It is advantageous if the user electronic circuit comprises a microprocessor or a gate array or ASIC type with a memory or a suitable combination of at least two of these elements, i.e. a microprocessor, a gate array or an ASIC type, which is thus constituted to be suitable for executing software operations to process the data transmitted by the optical sensor. 6 Captured output yarn 3 The image and the spinning station of the air-jet spinning machine 1 Detection of structural defects in yarn 3 during yarn production V device.

[0093] Software embodied in a computer-readable medium is an electronic device 7 As part of the software, the software is provided with program blocks or provided with instructions, the program blocks or instructions are suitable for executing software operations to process the optical sensor 6 Captured yarn 3 images and detect structural defects in yarns V , and making the method for detecting yarn according to the present invention 3 Structural defects V The entire device, which includes at least one yarn 3 Optical sensors 6 , the optical sensor 6 Having at least one row arranged adjacent to each other 610 Radiation-sensitive components 6100 , optical yarn sensor 6 Connect to electronic devices using software 7 , to operate according to the desired method, ie to perform the steps of the method according to the invention.

[0094] Computer readable media for use with the present invention include computer programs and software according to the above paragraphs.

[0095] For example, in the spinning station of the air-jet spinning machine 1 Wrapping yarn produced 3 Comprising: a core formed by a bundle of substantially parallel fibers 30 , whereby the yarn 3 Core 30 Wrapped with a fiber wrap comprising a wrapping fiber 31 and wild fiber 32 . Wrapping fiber 31 With a relatively regular pitch of the spiral R The spiral is wrapped around the yarn 3 Core 30 The wild fibers 32 are also wound around the yarn in a spiral 3 Core 30 around, but these spirals follow the yarn 3 The length of the thread has a variable irregular pitch, such as Figure 3 With the help of symbols R1 、 R2 、 R3 As shown, or wild fiber 32 With yarn 3 Core 30 The unfinished winding, and thus the formation of 3 Core 30 Protruding untwisted (free) end 320 Alternatively, wild fiber 3Has slack portions that form tufts or loops on the yarn surface 321 In addition, the wrapped yarn exhibits 3 The short slack portion of the core LN , wrapping fiber 31 The protruding end 310 , yarn 3 Core fiber 30 The protruding end 300 etc., and protruding or free ends 300 、 310 and 320 .

[0096] The present invention is used in the spinning station of the air-jet spinning machine 1 Production of wrapped yarn 3 An example of application is that optical yarns 3 sensor 6 Capturing the moving wrapping yarn 3 An image of at least a portion of the length of the yarn is obtained, thereby obtaining information about the yarn 3 Appearance (image) data D1 , that is, about yarn 3 Data on the visual appearance of the yarn, or more specifically, on the 3 According to these data D1 , and then extract descriptive data D2 ,data D2 Describes the yarn 3 Core 30 How the fiber is wrapped 31 and / or wild fiber 32 Entanglement, in other words, describes the visual yarn 3 Based on the extracted descriptive data D2 , determine the wrapped fiber 31 and / or wild fiber 32 Yarn 3 Core 30 Package S In the spinning station of the air-jet spinning machine 1 Yarn production 3 During this period, yarn 3 Core 30 Encapsulated fiber 31 and / or wild fiber 32 Package S is continuously determined, thereby detecting the yarn 3 Core 30 Encapsulated fiber 31 and / or wild fiber 32 Package S If the yarn is detected (i.e. found) 3Core 30 Encapsulated fiber 31 and / or wild fiber 32 Package S The change of yarn 3 Structural defects V The corresponding position of 4 As shown in .

[0097] In addition, due to the spinning station of the air-jet spinning machine 1 Yarn 3 The speed of movement, from the yarn 3 Visual changes in surface structure, i.e., yarn 3 Edge H Nearby yarn 3 Surface structure, from yarn 3 edge H It seems possible to determine very well the movement of the yarn 3 Core 30 Encapsulated fiber 31 and / or wild fiber 32 Package S , it's all along the yarn 3 surveillance area Z In, or in the yarn 3 In the envelope.

[0098] It seems that yarn 3 Visual changes in surface structure can be determined by 3 Surface structure analysis is performed to determine the yarn 3 Surface waviness K and / or based on wild fiber 32 The characteristics of the yarn are determined 3 wildness W .

[0099] If yarn is detected 3 Surface waviness K Deviation , for example, with yarn 3 Surface waviness K The long-term statistical average of the yarn exceeds the set judgment threshold, for example, more than 5%, and / or if the yarn is detected 3 wildness W Deviation , for example with yarn 3 wildness W If the long-term statistical average of the yarn exceeds the set judgment threshold, for example, more than 5%, the yarn is determined to be 3 Structural defects V The corresponding occurrence positions of Figure 4As shown in the picture.

[0100] In optical sensors 6 Sensing element 61 In the width direction of the yarn 3 Optical sensor 6 Sensing element 61 At least one line 610 element 6100 (which are arranged adjacent to each other) in the length direction of the yarn 3 Edge of the surface H The spectrum of the direction E The waviness of the wrapped yarn surface can be well determined in the frequency domain K In this frequency domain, determine or set at least one frequency range O , this frequency is very important for monitoring yarn 3 Edge of the surface H The spectrum of the direction E (Changes in edge orientation ) is important and within at least one determined or set range O Monitor and continuously evaluate the yarn 3 Edge of the surface H The direction of this spectrum E Based on at least one determined or set frequency range O Middle pair yarn 3 Edge of the surface H The spectrum of the direction E Monitoring and continuous evaluation of yarn 3 Surface waviness K , which basically describes the yarn 3 Core 30 Wrapping fiber 31 The spiral in the length direction or the sensed yarn 3 Direction of movement P Pitch on R behavior, i.e., it essentially describes the wrapped fiber 31 Yarn 3 Core 30 package.

[0101] yarn 3 Improved determination of the corresponding locations of structural defects is achieved through monitoring and continuous statistical evaluation of the yarn 3 Current waviness of the surface waviness K With yarn 3 Reference waviness of the surface Kref Deviation To execute. Yarn 3 Reference waviness of the surface Krefor are identified as coming from the same spinning unit 2 Yarn 3 Surface waviness K long-term average, and / or determined as a product set to produce the same yarn 3 Multiple spinning stations 2 Yarn 3 Surface waviness K Long-term average, and / or yarn 3 Reference waviness of the surface Kref According to the spinning station of the air-jet spinning machine 1 The current production parameters are set at the location.

[0102] To detect yarn structural defects V The position of the yarn currently detected 3 Surface waviness K Deviation from the set threshold The occurrence of, for example, more than 5%.

[0103] According to another embodiment of the present invention, an optical sensor is used 6 Sensing element 61 Yarn in the width direction 3 Edge of the surface H The spectrum of the direction E Yarn in the frequency domain 3 Surface waviness K Determination of yarn 3 Edge of the surface H The spectrum of the direction E To set at least one frequency range by comparing the long-term average O (This is useful for monitoring the edges of the yarn surface H The spectrum of the direction E (Changes in edge orientation ) is important) depends on the yarn 3 Current production parameters, especially those for yarns 3 Produced fiber materials 11 、 14 Type of yarn 3 Movement speed, spinning nozzle 20 The spinning pressure and the yarn spun 3 The fineness of the yarn depends on the spinning unit 2 The current components, in particular the type of spinning nozzle 20, are implemented.

[0104] yarn 3 Core 30 Package S The yarn can be determined by 3 wildnessW to determine well, which in principle evaluates the yarn 3 The degree of disorder of the structure, whereby this evaluation includes the evaluation of the yarn 3 Core 30 Encapsulated fiber 31 And wild fiber 32 Package, and evaluate the package fiber 31 itself, wild fiber itself, wild fiber 32 The free end 320 , wild fiber 32 The slack part 321 , yarn 3 Core 30 The short slack part LN , wrapping fiber 31 The protruding end 310 , yarn 3 Core 30 Protruding end of the fiber 300 Wait, it's all in Wild Fiber 32 The spectrum in the time domain, where the 3 Core 30 Edge H Limited area Z Determine or set at least one domain in OL , the domain OL For monitoring the yarn represented by the above parameters 3 The disorder in the structure is important. 3 structure 3 This determines or sets the domain of the disorder spectrum in OL In yarn 3 Core 30 The packages are monitored and evaluated, i.e., the yarn 3 Core 30 Encapsulated fiber 31 and wild fibers 32 Wrap, wrap fiber 31 Itself, wild fiber Itself, wild fiber 32 The free end 320 , wild fiber 32 The slack part 321 , yarn 3 Core 30 The short slack part LN , wrapping fiber 31 The protruding end 310 , yarn 3 Core 30 The protruding end of the fiber 300 wait.

[0105] According to the invention, by monitoring and continuously statistically evaluating the current yarn3 wildness W With yarn 3 Reference value of wildness Wref Deviation , using wrapped yarn 3 wildness W To evaluate yarn 3 Structural defects of yarn. 3 Reference value of wildness Wref or from the same spinning unit 2 Yarn 3 wildness W long-term average, and / or from a system configured to produce the same yarn 3 Multiple spinning stations 2 Yarn 3 wildness W Long-term average, and / or yarn 3 Reference value of wildness Wref According to the spinning station of the air-jet spinning machine 1 The current production parameters are set at the location.

[0106] For easy and quick evaluation, test the yarn 3 wildness W Deviation The occurrence of yarn exceeds the set judgment threshold, for example, more than 5%, to determine the yarn 3 Structural defects V The emergence of.

[0107] To facilitate setting the yarn 3 Structural defects V According to another embodiment of the present invention, the occurrence of the detection of 3 Production parameters, especially according to the yarn 3 Produced fiber materials 11 、 14 Type of yarn 3 Moving speed, spinning nozzle 20 The spinning pressure in the 3 The fineness and the spinning unit 2 Current components, especially the spinning nozzles 20 To determine the type of yarn 3 Wildness value W Important area settings.

[0108] To improve the detection of yarn 3 Structural defects V Accuracy, continuous monitoring of yarn 3 Surface waviness K and yarn 3wildness W , and according to the yarn 3 Surface waviness K Deviation and according to yarn 3 wildness W Deviation to determine the wrapped fiber 31 and wild fiber 32 Yarn 3 Core 30 The overall package KWS .

[0109] To detect yarn 3 Structural defects V , yarn 3 Core 30 The current overall package KWS With yarn 3 Core 30 The overall package KWS Reference KWSref Deviation is monitored and continuously statistically evaluated. 3 Core 30 The overall package KWS Reference KWSref Or in the same spinning unit 2 Yarn produced 3 Core 30 The overall package KWS Long-term average, and / or across multiple spinning stations 2 Yarn produced 3 Core 30 The overall package KWS The long-term average of the multiple spinning stations 2 are set to produce the same yarn 3 , and / or yarn 3 Core 30 The overall package KWS According to the spinning station of the air-jet spinning machine 1 The current production parameters are set at the location.

[0110] In another exemplary embodiment, the wrapping yarn 3 Made of yarn 3 Quality optical sensor 6 Sensing, the optical sensor 6 Simultaneous yarn sensing 3 At least one diameter parameter, in particular of a yarn 3 Diameter .

[0111] Industrial Applicability

[0112] The present invention is applicable to air-jet spinning machines for producing wrapped yarns. Furthermore, it is applicable to winding machines and, in principle, also to other types of textile machines for producing and / or processing and / or analyzing or measuring wrapped yarns, where it is necessary or desirable to evaluate the produced or processed wrapped yarns not only from the perspective of diameter characteristics and hairiness but also from the perspective of structural changes in the produced and / or processed yarns.

[0113] Reference List

[0114] 1 Spinning station

[0115] 10 cans

[0116] 11 long strips

[0117] 13 Drafting equipment

[0118] 14 Fiber Formation

[0119] 2 Spinning units

[0120] 20 Spinning nozzles

[0121] 21 Yarn outlet from the spinning nozzle

[0122] 3 Wrapping yarn

[0123] 30 core wrapped with yarn

[0124] 300 protruding end of the wrapped yarn core

[0125] 31 Wrapping Fiber

[0126] 310 protruding end of wrapped fiber

[0127] 32 Wild Fiber

[0128] 320 Free ends of wild fibers

[0129] 321 Slack of Wild Fiber

[0130] 4 Extraction mechanism

[0131] 5 Winding equipment

[0132] 50 spools

[0133] 6 Optical yarn sensor

[0134] 60 Radiation Source

[0135] 600 Collimating Optics

[0136] 61 Optical sensor element

[0137] 610 Rows of radiation sensitive elements arranged adjacent to each other

[0138] 6100 Radiation Sensitive Components

[0139] 62 measuring slots

[0140] 7 Electronic devices

[0141] D1 Data about the visual appearance of the yarn (on the yarn image)

[0142] D2 Descriptive data on how the yarn core is entangled with wrapped fibers and / or wild fibers, or descriptive data on what the visual structure of the yarn is

[0143] E Spectrum of the orientation of the edge of the yarn surface in the width direction of the sensing element of the optical sensor

[0144] Yarn diameter

[0145] H Yarn edge

[0146] Changes in orientation of yarn edges

[0147] K Yarn surface waviness

[0148] Deviation of yarn surface waviness

[0149] Kref Reference waviness of the yarn surface

[0150] KWS wrapped fibers and wild fibers wrap the yarn core

[0151] Reference overall wrapping of the yarn core

[0152] L is the length of the row of radiation sensitive elements arranged

[0153] Short slack in the LN yarn core

[0154] Frequency range important for monitoring the spectrum of edge orientation (edge ​​orientation changes) on the yarn surface

[0155] OL is important for monitoring disorder in the yarn structure in the time domain of the wild fiber spectrum in a limited area along the edge of the yarn core.

[0156] P is the direction in which the yarn moves during production

[0157] R is the pitch of the helix wrapping the fiber

[0158] R1, R2, R3: Pitch of the helix of wild fibers

[0159] S yarn core wrapping

[0160] V Structural defects of yarn

[0161] W Yarn Wildness

[0162] Deviation of yarn wildness

[0163] Wref Reference yarn wildness

[0164] Z Monitoring area along the yarn

Claims

1. A method for detecting structural defects in a wrapped yarn, the wrapped yarn comprising a core formed of parallel fibers, whereby the core is bound together by a fiber wrap, the fiber wrap comprising wrap fibers and wild fibers, the wild fibers being fibers wound around the yarn core in a spiral with a variable pitch or a variable direction or not completely wound around the yarn core, wherein structural defects in the wrapped yarn in specific locations or portions do not significantly affect the quality and / or diameter characteristics of the wrapped yarn or the yarn hairiness parameters in these locations or portions of the wrapped yarn, the method being characterized in that - an image of the moving yarn is captured by at least one optical yarn sensor over at least a portion of the yarn length, - whereby the optical yarn sensor comprises at least one row of radiation-sensitive elements and at least one radiation source, - said optical sensor is connected to an electronic device equipped with software, - the yarn images thus captured are processed by digital image analysis methods to obtain data on the yarn surface structure, - based on the data obtained, evaluate the evolution of the yarn surface structure along the yarn length, - comparing these changes in the yarn surface structure with pre-set standards, - and if these changes in the yarn surface structure exceed the predetermined criteria, the relevant position of the yarn is determined as the location of occurrence of a yarn structural defect.

2. The method according to claim 1, wherein - said optical sensor captures an image of the wrapping yarn along said yarn edge, - the captured yarn images are processed by using digital image analysis methods to obtain data about the yarn structure along the yarn edges, - based on the data obtained, evaluating the changes in the yarn structure along the edges of said yarn, - comparing these variations in the yarn structure along said yarn edges with pre-set standards, - and if these variations in the yarn structure along said yarn edge exceed said pre-set criteria, the relevant position of the yarn is determined as the location of occurrence of a yarn structure defect.

3. The method according to claim 1 or 2, wherein - the optical yarn sensor captures an image of the envelope of the wrapping yarn along the yarn edge, - Analysing the image of the yarn envelope for lateral deviations from the straight direction of the yarn and / or for disorder in the yarn structure by means of digital image analysis methods.

4. The method according to claim 3, wherein - in order to analyse the lateral deviations of the image of the wrapped yarn envelope from the straight direction of the yarn, evaluating the changes in the orientation of the edges of the yarn image relative to said optical yarn sensor, - thereby determining or setting at least one frequency range of the frequency spectrum of the orientation of the yarn surface edge, and - monitoring and continuous evaluation of the frequency spectrum of the position of the edges of the yarn image in at least one determined or set frequency range, - determining the waviness of the yarn surface as a function of the deviation of the yarn envelope from a straight yarn direction based on the monitoring and continuous evaluation of the frequency spectrum of the orientation of the edges of the yarn image in at least one determined or set frequency range, - the current lateral deviation of the image of the yarn envelope from the straight yarn direction is continuously statistically evaluated and compared with a reference value of the yarn surface waviness, wherein, The reference value of the yarn surface waviness is formed by a long-term average of yarn surface waviness values ​​from the same unit and / or a long-term average of yarn surface waviness values ​​from a plurality of units set for producing, processing or analyzing the same yarn, and / or the reference value of the yarn surface waviness is set according to current production, processing or measurement parameters of a production, processing or measurement machine, and A structural defect of the yarn is detected when the occurrence of a current deviation of the waviness of the yarn surface from a reference value for the surface waviness exceeds a set decision threshold.

5. The method according to claim 4, wherein - The range of analyzed frequencies of the spectrum for setting the orientation of the edge of the wrapped yarn depending on the current yarn parameters, in particular the type of fiber material used for yarn production, the speed of yarn movement, the spinning pressure in the spinning nozzle, the fineness of the spun yarn and the current components of the spinning unit, in particular the type of spinning nozzle.

6. The method according to claim 3, wherein - determining or setting at least one area for monitoring the wild fiber image over at least a portion of the yarn length, for analyzing disorder in the wrapped yarn structure, said area being important for monitoring disorder in said yarn structure, and - In this area, the yarn disorder is monitored and evaluated, and - determining the yarn wildness based on disorder in the yarn structure, as a function of the presence of irregularities in the wrapping yarn structure and / or as a function of the presence of irregularities in the wrapping yarn surface structure, and - monitoring the yarn wildness and comparing it with a reference value of the yarn wildness, whereby the reference value of the yarn wildness is a long-term average of yarn wildness values ​​from the same unit and / or a long-term average of yarn wildness values ​​from a plurality of units set up to produce or process or measure the same yarn, and / or the reference value of the yarn wildness is set according to current production or processing or measurement parameters of a production or processing or measurement machine, and A structural defect of the yarn is detected when a current deviation of the yarn wildness from a reference value of the yarn wildness occurs that exceeds a set decision threshold.

7. The method according to claim 6, wherein - The area for monitoring the wild fiber image over at least a portion of the wrapped yarn length is set depending on the current yarn parameters, in particular the type of fiber material used for yarn production, the speed of yarn movement, the spinning pressure in the spinning nozzle, the fineness of the spun yarn and on the current components of the spinning unit, in particular the type of spinning nozzle.

8. The method according to claim 3, wherein - An analysis of the lateral deviations of the image of the wrapping yarn envelope from the linear direction of the yarn and an analysis of disorder in the yarn structure are performed simultaneously.

9. The method according to claim 1 or 2, wherein - While capturing the yarn image for detecting structural defects of the wrapping yarn, the optical yarn quality sensor senses at least one yarn diameter parameter, in particular the yarn diameter.

10. A device for detecting structural defects of a wrapped yarn, the device having at least one optical yarn sensor having at least one row of radiation-sensitive elements, and the device further having at least one radiation source, and means suitable for performing the method according to any one of claims 1 to 9.

11. The device according to claim 10, characterized in that - The optical yarn sensor is formed by an optical sensor of the yarn quality.

12. The device according to claim 10 or 11, characterized in that - an apparatus suitable for carrying out the method according to any one of claims 1 to 9, comprising a microprocessor with memory or a gate array or a user electronic circuit of the ASIC type, or a combination of at least two of these elements.

13. A computer program product comprising instructions for causing an apparatus according to any one of claims 10 to 12 to perform the steps of the method according to any one of claims 1 to 9.

14. A computer-readable medium having stored therein the computer program product of claim 13.

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