WO2019130209A2

WO2019130209A2 - Yarn quality monitoring (methods and systems)

Info

Publication number: WO2019130209A2
Application number: PCT/IB2018/060583
Authority: WO
Inventors: Petr Perner; Josef Suska; Ondrej ZELINKA
Original assignee: Petr Perner; Josef Suska; Zelinka Ondrej
Priority date: 2017-12-26
Filing date: 2018-12-24
Publication date: 2019-07-04
Also published as: CN111670358A; EP3732470A2; WO2019130209A3

Abstract

Disclosed are methods of monitoring textile yarn quality and apparatuses for monitoring textile yarn quality. Moving textile yarn 1 is monitored for its quality to meet required criteria, e.g. evenness or presence of unwanted foreign fibers. Light illuminating by light sources 2 and/or 7 and an image sensor 3 are used. The yarn 1 is placed as an obstacle into the pathway 100 of one diffused 5 light 2, contours of the light being focused 6 for a sharp yarn contours image capture. The light 7 is reflected from the yarn 1 and propagates along a path 100 to the image sensor through diffraction element 8. Portion of reflected light is diffracted 8 and creates interference pattern. Remaining reflected light creates yarn image. Thus light 2 directly illuminates image sensor. Light 7 illuminates moving yarn 1 and light from light source 7 is reflected from the yarn and illuminates image sensor. The yarn diameter is determined by processing of the yarn contours image or yarn image. The color analysis of the yarn 1 is determined by processing of captured interference patterns. Further evaluation of yarn diameters is used for yarn evenness monitoring and further color analysis results evaluation is used for foreign fibers monitoring.

Description

YARN QUALITY MONITORING (Methods and Systems)

The invention relates to a method and device for diameter measuring and color inspection of a linear textile formation such as yarn, thread, textile fibers and slivers.

Yarn is a textile formation made by spinning of a relatively short fibrous material into a long continuous unit. Raw cotton is used as one of the many input materials for yarn production. Machine yarns are wound onto coils for easy storage and further processing.

Yarn evenness and foreign fibers are important quality parameters in yarn. Yarn evenness refers to the variation in diameter along its length, as yarn has small changes in diameter along its length. There are numerous locations of thick and thin portions along the yarn length. This affects evenness of the yarn.

"Foreign fiber" is the presence of foreign particles in the textile yarn. Textile yarn is generally white in color. A presence of foreign fiber interfers with color homogeneity of the yarn. Yarn color analysis detects or determines the presence of foreign fibers. This is one type of monitoring. Yarn evenness and foreign fiber are affected by quality of the materials used.

Yarn evenness is also affected during manufacturing by spinning machines. As yarn is produced rapidly and in high volumes, manual inspection by human inspectors is not feasible, but rather impractical, and not possible to an extent required by automated manufacture.

The invention provides methods and apparatus, e.g., systems and devices, for monitoring yarn quality for measuring yarn diameter and detecting foreign fibers. The present invention is particularly suitable for mass machine production of yarn, which has increased resistance against accumulated dust particles and which is easily realizable.

Embodiments of the invention of claim 11 provide methods for yarn quality monitoring, which are carried out by a primary light source directly illuminating an image sensor through a focusing element. Longitudinally moving yarn is placed as an obstacle between the light source and the image sensor. Images of yarn contours are focused on the image sensor. The longitudinally moving yarn is guided by guiding elements, and is split into small consecutively measured yarn segments whose longitudinal dimension is defined by a longitudinal dimension of a photosensitive area of the image sensor, the speed of yarn movement, and the image sensor sampling rate. Image sensor data for each measured segment is evaluated and the diameter of the yarn is calculated.

Embodiments of the invention provide a setup of the yarn, to create an obstacle in the diffused light beam, such that the focusing element creates images with sharp yarn contours suitable for accurate determinations of yarn diameter. By using the focusing element, the effects of dust particles accumulated on both optical surfaces (emitter and receiver) placed out of focus are eliminated. Additionally, unwanted ambient light rays coming from the sides are directed outward from the image sensor by the focusing element.

In embodiments of the invention, two types of light sources are used: a primary light source, which directly illuminates an image sensor, and, a secondary light source, whose rays are reflected from the yarn before they reach the image sensor.

In other embodiments of the invention of claim 12, a diffraction element is used for diffracting at least portion of light rays. Diffracted light rays create an interference pattern on the image sensor. Undiffracted light rays, originating from the primary light source create a yarn contour image on the image sensor (the "yarn contour image" or "contour image" is created from yarn shadows and non blocked primary light source rays). Undifracted light rays originating from the secondary light source (reflected from the yarn), create a yarn image on the image sensor. Image sensor captured data (image data or pixel data) is created as any combination of yarn contour image, yarn image and interference patterns.

Embodiments of the present invention eliminate problems of prior art, where dust particles and fibers on optical surfaces create sharp shadows on the image sensor. These shadows make accurate yarn diameter evaluation impossible. Embodiments of the present invention are such that particles accumulated on the optical surfaces do not create shadows on the image sensor, even if its size is comparable with the measured yarn itself. Only light intensity on the image sensor will be lower. However, this effect is compensated for by increasing power of the primary light source, see claims 16, 17. Another advantage of using direct image sensor illumination is that significantly lower power of the primary light source is needed to excite the image sensor pixels, than that for configurations where reflected light is captured for yarn diameter processing (not monitoring).

In another embodiment of the present invention of claim 12, measured parts of yarn are illuminated by a secondary light simultaneously with the illumination from the primary light source. The secondary light source is placed on same side of yarn as the image sensor. Light rays from the secondary light source are reflected from the moving yarn and are focused on the image sensor by a focusing element. Secondary light rays reflected by the yarn are diffracted by a diffraction element (placed in front of focusing element or in front of the image sensor), and an interference pattern is created. The focusing element significantly improves image quality. Images of moving yarn contours and its respective interference pattern are simultaneously (see claim 15) captured by the image sensor for further diameter measurements and color analysis of the longitudinally moving yarn. The present state of the art thinks it is sufficient to measure only "an amount of reflected light from the yarn and yarn diameter" (for foreign fibers detection). There was no suggestion however to measure real foreign fibers color during yarn mass machine production up to now. s Foreign fiber presence is along the invention detected as change of reflected light (intensity only) for known/measured diameter. When mentioning color analysis for foreign fibers s detection it is evident that it is superior to have information about real color of foreign fibers detection. The claimed diffraction element allow to combine different types of information on a single image sensor and measuring true color analysis of the running yarn. This opens the possibility of only amount of reflected light (calculated from interference pattern) is used for

: ? foreign fiber detection (no exact RGB color processing is applied). ₄ The claimed setup with mentioned diffraction element is thus not only useful but as well advantageous even if no exact color information is needed.

"Color analysis" may thus be understood as "reflectivity analysis" and is broader in technicals understanding. To include true color analysis and simpler methods too, for example

measuring only reflectivity of the running yarn based on the reflected amount of light from this yarn and its diameter.

Embodiments of the invention are such that when the diffraction element is employed, the direct color sensing is not used, such that a monochromatic image sensor is used.

Measured yarn segment color information is obtained by the processing of light intensity at corresponding pixel positions on the image sensor. Corresponding pixel position depends on color wavelength, yarn diameter, and yarn position. The monochromatic image sensor has high sensitivity and high resolution, while being inexpensive.

Embodiments of the invention are such that when using a diffraction element with a zero order mode feature, part of the light rays pass un-diffracted through the diffraction element, and are focused on the image sensor as a yarn image or yarn contour image. The interference pattern created by the diffracted rays is obtained by being captured simultaneously with the yarn image and/or the yarn contour image by the image sensor. Color analysis is obtained by processing of captured interference pattern and yarn diameter is obtained by processing of captured yarn contour image and/or yarn image.

For yarn quality monitoring, color analysis and yarn diameter are obtained from the same yarn segment. This is in contrast to the contemporary art, where yarn segment data for color analysis and yarn segment data for yarn diameter calculations are captured by separate independent light detectors, which require data synchronization, depending on the speed at which the yarn is moving.

Embodiments of the invention of claim 13 are such that monochromatic light, RGB (Red- Green-Blue) light, white light, UV (Ultra-Violet) light, and IR (Infra-Red) light is used as the s secondary light source. This secondary light source illuminates the yarn, and the image sensor captures light rays reflected from the yarn. Specific light wavelengths are suitable for foreign s fiber detection and monitoring of various yarn materials, e.g. cotton, wool, or synthetic

materials such as polypropylene.

Embodiments of the invention of claim 14 are such that the primary light uses wavelengths different from secondary light. Such wavelength selection in combination with optical filter, which partially covers the image sensor, allows the use of primary light rays only to measure the diameter of the yarn (moved longitudinally). 6 In other embodiments of the invention of claim 17 or 16, parameters of primary light and/or the secondary light source are controlled, preferably via feedback. The feedback is based ons the quality of previously captured images. For example, light intensity is increased when images with low light intensity were previously captured.

Embodiments of the invention of claim 1 are directed to an apparatus in the form of a device for yarn quality monitoring. The device includes at least one primary light source illuminating the image sensor, at least one focusing element, at least one image sensor, and a control unit for processing image sensor data. The provided measurement enables monitoring of the yarn quality.

The device of claim 1 includes a primary light source, which emits diffusive light, or an additional light diffuser is used. The device also includes at least one optical element in an optical path of primary light for focusing of a yarn contour image on the image sensor.

In other embodiments of the invention of claim 2 the device has a secondary light source for illuminating the yarn and diffraction element is provided in the optical path.

In other embodiments of claim 3, the diffraction element is a diffraction grating. The advantage of the diffraction grating is simplicity and economics.

Other embodiments of the device of claim 5 employ monochromatic light, RG B-light, white light, UV-light, IR-light, as a secondary light source. Secondary light source illuminates the yarn and the image sensor captures light reflected from the moving yarn. Specific light wavelengths or its combination, are suitable for detection and monitoring of various yarn materials, e.g. cotton, wool or synthetic materials, such as polypropylene.

Other embodiments of the invention of claim 4 utilize a primary light source with wavelengths different from the secondary light source. Such wavelength selection in combination with an optical filter, covering partially the image sensor, allows for the use of the primary light source only as a single source for measuring the diameter of the yarn.

In another embodiment, the device includes sources of primary and/or secondary light, which are controlled via e.g., feedback, based on the quality of previously captured images. For example, light intensity is increased when images with low light intensity were previously captured.

In other embodiments of the device claim 7 or 6 the focusing element is formed by at least one lens or a combination of lenses, from the group of aspherical lens, mirror lens, convex lens, and concave lens. Lenses or combinations of lenses can be mounted in an M12x0.5 package, see http ://www. m 12 lenses. Board- Lenses-s/12. htm

The size and pitch of M12x0.5 package allows for the adjustment of a focus distance, and the M12x0.5 package is available at low costs.

In other embodiments of the device of claim 8 the image sensor is formed by at least one line or array of light-sensitive pixels. Individual pixels or regions of pixels can be covered with an optical filter layer for specific ranges of light wavelengths. This simplifies further processing of the captured images for diameter measurements and yarn color analysis.

In other embodiments of the device of claim 9 the image sensor pixels can include micro lenses for increased sensitivity and limiting of wide angle light rays, such that the image is made sharper.

In another embodiment of the device according to claim 8 the image sensor is a charge coupled device type. This CCD image sensor is used, as it has high sensitivity and incurs low cost.

Alternatively, the device may have an image sensor of a complementary metal oxide semiconductor type. Those CMOS image sensors have high speed and low power

consumption. In another embodiment of the device of claim 10 or as stand-alone device of claim 36 a

control unit is provided with a programmable logic array ( P LA), preferably an FPGA, or an application specific integrated circuit (ASIC), for fast parallel image data processing, microcontroller for yarn quality monitoring, light source control circuits and power supply. s In another embodiment an ASIC can be used to integrate image sensor with data processing on one chip.

The present invention is an advancement over the prior art, as it allows for accurate yarn measurements and color analysis when significant amounts of dust particles are present. Additionally, the invention provides methods and devices able to measure yarn diameters and :? detect foreign fibers from the same image data, as captured by an image sensor. Embodiments of the invention are directed to a yarn quality monitoring device or system.

The device comprises: a primary light source (e.g., a primary light source) for emitting light,6 the light propagation (e.g., travel) defining an optical path; a diffuser proximate to the first light source for diffusing the emitted light; an image sensor illuminated by the diffused lights emitted from the primary light source, for capturing a yarn contour image from illumination of a moving yarn in the optical path; a focusing element in the optical path between the first .14 light source and the image sensor, for focusing the yarn contour image on the image sensor;

and, a controller in communication with the image sensor for processing the captured yarn contour image, to determine yarn diameter.

Optionally, the device additionally comprises: a secondary light source (e.g., a secondary light source) for illuminating the yarn, the reflected light propagation defining an optical path; a > diffraction element in the optical path, between the yarn and the image sensor, the

diffraction of secondary light source light reflected from the yarn for interference pattern creation on the image sensor; and, the controller is also configured for processing

the interference pattern to obtain yarn color analysis.

Optionally, the diffraction element is a diffraction grating.

Optionally, the primary light source and the secondary light source emit light at different wavelengths, and the device further includes an optical filter at least partially covering the image sensor for blocking light reflected from the yarn illuminated by secondary light source. Optionally, the secondary light source emits one or more light types including monochromatic light, RG B (Red-Green-Blue) light, white light, UV-light (ultraviolet light) or IR-light (infra-red light).

Optionally, the focusing element includes one or more lenses such as aspherical lenses, s mirror lenses, convex lenses, concave lenses and combinations thereof. s Optionally, the focusing element includes one or more lenses in an M12x0.5 package. The package functionally symbolizes a lens holder with a lens held thereby.

Optionally, the image sensor comprises: one or more lines of photosensitive pixels; and,

: ? optionally, the image sensor is type of a CMOS (complementary metal oxide semiconductor) sensor or a CCD (charge coupled device).

Optionally, the image sensor includes micro-lenses configured to limit wide angle light rays.

Optionally or independently the controller comprises: a programmable logic array (PLA) fors image data processing, to obtain yarn diameter and/or yarn color analysis; a light control circuit in communication with the PLA, which is controlled by the PLA; and, a microcontroller in communication with the PLA, the microcontroller programmed to evaluate the yarn eveness, and/or the yarn foreign fiber content, from the processed image data.

Embodiments of the invention are directed to a method of yarn quality monitoring. The method comprises: illuminating an image sensor with light from a primary light source configured for creating a contour image of a yarn on the image sensor, the primary light > source diffused by a diffuser and focused by a focusing element, on an image sensor,

the primary light source, diffuser and focusing element aligned to define an optical path; obtaining a contour image of the yarn by the image sensor, the moving yarn positioned in the optical path between the primary light source and the image sensor; and, processing the yarn contour image to obtain a yarn diameter for the purpose of yarn quality monitoring.

Optionally, the method further comprises: illuminating the moving yarn by a secondary light source, such that the light from the secondary light source is reflected from the moving yarn; focusing the reflected light on the image sensor; diffracting the reflected light from the moving yarn to cause the creation of an interference pattern on the image sensor;

obtaining the interference pattern from the image sensor; and, processing of the interference pattern for obtaining a yarn color analysis. Optionally, the method is such that the secondary light source emits at least one type of light including: monochromatic light, RGB light, white light, UV light, IR light, and combinations thereof.

Optionally, the method is such that the illuminating by the primary light source is at s a wavelength different from a wavelength of light emitted from the secondary light source, and optionally, the method further comprises: covering a portion of the image sensor with s an optical filter; passing the emitted light from the primary light source through the optical filter to a portion of the image sensor; and, blocking light reflected from the yarn, to cause illumination from only the primary light source for measuring a diameter of the moving yarn.

: ? Optionally, the method is such that the capturing of the contour image of the moving yarn and the capturing of the interference pattern is performed simultaneously by the image₄ sensor. 6 Optionally, the method is such that it additionally comprises: controlling the primary light source to emit light at an intensity based on processing results from a previously captureds image from the image sensor in a feedback loop.

.14 Optionally, the method is such that it additionally comprises: controlling the secondary light source to emit light at an intensity based on processing results from previously captured ..¾ image from the image sensor in a feedback loop.

As evident from the previous disclosure, the primary and secondary light may be termed first and second lights (or even light and further light, as used in claim 18 and 28). One light is a > direct light from the light source to the image sensor (inbetween it passes the longitudinally moving yarn). The other one is a reflected light from the moving yarn. Both types of light may be an independent disclosure and claim (or a combination thereof).

Unless otherwise defined herein, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein may be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. Additional objects and features of the invention will become apparent upon reading of the detailed description of embodiments of the claimed invention and the claims. No feature shown in the embodiments (and the drawings) is to be regarded as essential, to be required in the claims, which should not mean it is not disclosed at its place of mention.

Reference to the drawings is made ...

FIG. 1 is a perspective view of a system in accordance with an

embodiment of the invention.

FIG. la is a another perspective view of a system in accordance with

an embodiment of the invention using yarn thickness changes along a

length portion of the longitudinally moving yarn.

FIG. 2 is a perspective view of a system in accordance with an

embodiment of the invention.

FIG. 2a is a perspective view of a system in accordance with another

embodiment of the invention, using only light source 7 providing

reflected light from the moving (running) yarn 1.

FIG. 3 is a block diagram of the controller of FIGs 1 and 2.

FIGs 4A and 4B are flow diagrams of processes performed in the

controller of the systems of FIGs 1 and 2, for yarn evenness

monitoring and foreign fiber detection.

It is understood that the below described and depicted particular embodiments are presented for illustration and not to limit the disclosed and claimed invention to such examples.

Embodiments of the present invention concern functionally yarn quality monitoring, for example, for all yarns used in the textile industry.

FIG. 1 shows a yarn quality monitoring system in an exemplary device, where a primary light source 2 (first light source) directly illuminates an image sensor 3, such that the light propagates along an optical path 100. This through a diffuser 5 and a focusing element 6, for example. Guiding elements 10 (e.g. guided by spaced apart elements 10a and 10b that may be provided for orienting or stabilizing the moving yarn 1) stabilize the longitudinally moving yarn 1. The yarn 1 is guided as an obstacle for diffused light from the light source 2, which illuminate the image sensor 3 behind the yarn.

A segment or portion of the moving yarn 1 as used in this description is shorter than displayed thick and thin places ly and lx so several measured consecutive segments may represent whole thick or thin place for purpose of monitoring the yarn.

FIG. la explains the set-up of FIG 1 and has the longitudinally moving yarn 1 that has in the measuring segment a thick place ly in the yarn 1 and is shown in such a position that contour image of a portion of this thick place ly is focused on the image sensor 3. The image sensor is receiving the light rays from light source 2, diffused by element 5 and focused by element 6. The conversion into an electrical signal is done by the image sensor - and depending on the type of image sensor, CCD-type or CMOS-type, line-oriented or surface oriented, the output 3a conveys a serial signal or a bus signal with several data lines, represented by the "x" along the electrical signal line or path 3a.

Segment of the yarn (portion or sample) is continuous portion of the yarn which goes through focal point of the focusing element (its image is focused on the image sensor 3) during integration (exposure) time of the image sensor. This time can be for example 37psec (for an exemplary frame rate of 27kFHz of the image sensor 3). When yarn 1 is longitudinally moving at 400m/min (= 6.7m/sec) a yarn segment has about 0.25mm length (it will indeed be influenced by the focusing element 6 and size of the image sensor pixels, thus the speed Vi of the yarn and sensor sampling rate 1/T₃ (T₃ being the sampling time (interval)) is most important).

Information about a yarn segment (in this exemplary implementation it is 0.25 mm of the yarn length) is contained in the pixel data (one frame/image of the image sensor, one line of pixels as sensor 3).

Monitoring uses a consecutive measuring of (non-same) yarn segments as to their properties, such as a diameter and/or a color and/or a reflectivity. This as it goes through focal point of the focusing element (the yarn 1 is moving along axis 200). Further evaluation of measured data for yarn quality data logging or immediate actions (for example cut yarn thick place away). The same applies for yarn thin places lx, shown at a position slightly above the thick place ly. With the next sampling, when the thin place lx goes through the focal point, a measuring establishes another data in the log chain. The faster the pixel data sampling (at same speed Vi of the yarn 1) the shorter yarn segments are measured for yarn quality monitoring.

Turning to FIG. 2, the focusing element 6 directs the non-blocked light rays through a diffraction element 8 making an image of yarn contours on the image sensor 3. For example, a diffraction grating can be used as standard and easily available diffraction element 8. A yarn contour image, also referred to herein as a contour image, for example, is an image created from a yarn, such as a moving yarn 1, by light from the primary light source 2 not blocked by the yarn, and the shadow(s) of the yarn. Yarn diameter is determined by processing of yarn contour image(s) on the image sensor 3, by the controller 4 (also referred to as control unit). As shown in FIG. 2, a secondary light source 7 (second light source) is added to the system of

FIG. 1. This secondary light source 7 emits light at a wavelength different from primary light source 2. The term "primary" and "secondary" are names to identify the light sources, others are 2 and 7 and even other names are first and second light source. Primary and secondary is not meant to give them priorities. And light sources that are employed by technical equipment are generally no natural light origin, but "artificial light", that is read implicitly when activating light and illuminating a longitudinally moving yarn segment. The disclosure is not meant to switch on the (natural) sun to prepare yarn quality monitoring.

This secondary light source 7 is placed on the same side of the moving yarn 1 as the image sensor 3, and serves to illuminate a portion of the moving yarn 1. The secondary light source 7 may be a plurality of the same or different light sources 7.

The emitted light reflected from the yarn 1 also propagates along an optical path 100 to the image sensor 3, this along a front portion of this optical path 100. More than one secondary light source(s) 7 are used, for example, for detecting of foreign fiber material(s) or to increase illumination intensity.

The full optical path from Light source 7 is of angled nature, starting at light source 7 along a first path portion 120 and after the light illuminates the moving yarn 1 and being reflected therefrom the path is the same as path 100, mentioned earlier. This is the from path portion of the full, straight path 100 starting at the light source 2.

The diffraction element 8 serves to diffract at least a portion of secondary light rays reflected from the moving yarn 1, which creates an interference pattern on the image sensor 3. For example, for white light, the diffraction element 8 creates rainbow spectra. The remaining portion of the reflected light rays passes through the diffraction element 8, without being diffracted, and creates a focused yarn image on the image sensor 3. This focused yarn image is, for example, used for diameter measurement of the yarn 1.

When the diffraction element 8 is employed, a color image sensor, as the image sensor 3 is s replaced by a monochromatic image sensor, as the image sensor 3. A monochromatic image sensor, as the image sensor 3, allows for high sensitivity and high resolution. Measured yarn s segment color information is obtained from a captured interference pattern by the

processing of light intensity at corresponding pixel positions on the image sensor 3.

When the diffraction element 8 has a zero order mode feature, a portion of the light rays : ? passes un-diffracted through the diffraction element 8, and are focused on the image sensor

3, as a yarn image and/or yarn contour image. The interference pattern created by the diffracted rays is obtained by being captured simultaneously with the obtaining by capturing the yarn image and/or yarn contour image by the image sensor 3, and is processed (in the6 controller 4) to obtain a color analysis. This is e.g. helpful for determining foreign fiber(s) in the yarn, e.g., a foreign fiber content moving in the yarn, as well as a determination of yarns diameter. The yarn quality may be monitored, such that color analysis and yarn diameter are obtained from the same yarn segment (or portion).

An optical filter 9 may partially cover the image sensor 3, and allows for the passage of only rays from the primary light source 2. These may be used for diameter measurement of the yarn 1, while the optical filter 9 blocks light rays from the secondary light source 7.

Interference pattern processing by the controller 4 may be used to determine the presence of foreign fiber(s) in the yarn 1.

The yarn contour image and interference pattern are captured by the image sensor 3, contemporaneous in time, and for example, at the same time.

The interference pattern may originate from the secondary light source 7, based on light rays reflected from the yarn, while the yarn contour image may originate from the primary light source 2.

Processing the light intensity of interference pattern at specific distances from the yarn image on image sensor 3 can be used for color analysis of the yarn 1. For example, the detection of foreign fiber(s) in the yarn 1 is achieved by a color image sensor, as the image sensor 3. A monochromatic image sensor 3 may be used as the image sensor 3. IB

The secondary light source 7 serves to illuminate the yarn contemporaneously, and, for example, simultaneously, with the illumination from the primary light source 2. The secondary light source 7 is placed on same side of yarn 1 as the image sensor 3. Light rays from the secondary light source 7 are reflected from the moving yarn 1 and are focused on the image sensor 3 by the focusing element 6. Light rays from the secondary light source 7 reflected by the yarn 1 are diffracted by a diffraction element 8 (placed in front of focusing element 6 or in front of the image sensor 3). An interference pattern is thus created at the image sensor 3.

Images of moving yarn contours and its respective interference pattern are simultaneously captured by the image sensor 3, for further diameter measurements and color analysis. The focusing element 6 improves image quality at the image sensor 3.

Should foreign fiber detection be desired, the secondary light source 7 for illumination is used to create an interference pattern, for example, through the diffraction element 8 (along with processes from the controller 4, as detailed below). The secondary light source 7 is, for example, of specific wavelengths, such as those for monochromatic light, RGB light, white light, UV-light, IR-light or any combination(s) thereof.

The focusing element 6 serves to eliminate distortion effects, caused by dust particles or other foreign or ambient particles, accumulated on optical surfaces (light sources 2, 7 and the focusing element 6). Additionally, the focusing element 6 directs unwanted lateral ambient light rays, directing these ambient light rays away or outward from the image sensor 3.

The focusing element 6 may be formed as a single lens or a set of lenses, the lens or lenses may include aspherical lenses, mirror lenses, convex lenses, concave lenses, and

combinations thereof. The focus may be adjustable by rotating a lens housing of the focusing element 6 by manipulating an adjusting thread.

For example, M 12x0.5 type of the focusing lens with housing is used, as its thread pitch fully satisfies the application of the apparatus, and such a lens has low acquisition costs. The size and pitch of M 12x0.5 package allows for the adjustment of a focal distance. Several lenses may be used, depending on the image quality for the presently measured yarn 1.

The image sensor 3 is formed, for example, by at least one line of light sensitive pixels. Each of the pixels is, for example, a square or rectangular shaped light sensitive area. Individual pixels can be monochromatic or sensitive for specific ranges of wavelengths. The image sensor 3 is, for example, a CCD-type or CMOS-type, and is formed as one or more lines of photosensitive pixels. Each of the pixels of the image sensor 3 includes, for example, a micro lens for increased sensitivity and for limiting wide angle light rays, resulting in sharper images. The light source 7 as shown in FIG. 2a illuminates the moving yarn 1 alone, without illumination from light source 2. The light source 7 is placed on the same side of the yarn 1 as the image sensor 3. Light provided by this light source 7 is reflected from the moving yarn 1 and focused on the image sensor 3 by the focusing element 6. A portion of light rays from the light source 7 is reflected by the moving yarn 1 and diffracted by a diffraction element 8 that is placed in front of focusing element 6 or in front of the image sensor 3. In the drawing the diffraction element 8 is in the optical path between focusing element 6 and image sensor 3.

An interference pattern is thus created at the image sensor 3 for moving (running) yarn color analysis. Remaining un-diffracted light rays create a yarn image on the image sensor and is used for diameter processing when only light source 7 applies.

An interference pattern is thus created at the image sensor 3 using only yarn reflected light.

FIG. 3 shows the function of the controller 4. The controller 4 may include a power supply 38 and a computer, for example a microcontroller 30, having an integrated circuit with a processor core with other embeded functions, such as l/O-peripherals (I/O is input/output), data memory, program memory. The controller 4 may also include an l/O-interface 34, light source control circuits 35 and a programmable logic array module 36 (PLA module). The PLA module 36 functions in yarn diameter calculations and color analysis from captured image data.

The program memory of the microcontroller 30 (e.g., ARM, Atmel AVR, Intel 8051, as well as any combinations thereof) stores executable instructions running the algorithms for determining yarn eveness (thick and thin places), see FIG. 4A, and foreign fiber detection, see FIG. 4B. The l/O-interface 34 serves for data exchange with a host system. The host system is, for example, a central unit of a spinning machine yarn quality control system (or the central unit of a winding machine yarn quality control system). The host system can be

integrated with the central unit of the entire spinning/winding machine, or it can be separate. The host system links to the controller 4 via a communication bus.

The controller 4 may include the light source control circuits 35, which may be controlled by the PLA 36. For example, the image sensor 3 and functionalities of the control unit 4 can be integrated in an Application Specific Integrated Circuit (ASIC circuit), to simplify the device and provide a low cost solution to yarn quality measurement. All of the components of the controller 4 may communicate with each other, directly or indirectly. Shown is a bus architecture B that allows communication of the devices in the controller. There may be more such bus architecture, especially for independent communications. The controller may control the parameters of the primary light source 2 and/or the secondary light source 7 via feedback to the PLA 36. The feedback is based on the quality of at least one previously captured image from the image sensor 3, as linked to the PLA 36. Preferably more images are used. For example, light intensity is increased (as signalled to the primary and secondary light source from the light source control circuits 35), when images with low light s intensity were previously captured by the image sensor 3. s Attention is now directed to FIGs. 4A and 4B, which show flow diagrams detailing computer- implemented processes in accordance with further embodiments. Reference is also made to elements shown in FIGs. 1 to 3. The process and subprocesses of FIGs. 4A and 4B are computerized processes performed by the controller 4. The aforementioned processes and : ? sub-processes can be, for example, performed manually, automatically, or a combination thereof, and, for example, in real time.

In FIG. 4A yarn diameter analysis and determination begins as pixel data (from the image 6 sensor 3), based on light emitted from the (primary) light source 2, is read by the PLA 36, at block 402, for each yarn segment of a predetermined length. The PLA 36 then applies rules s and policies to the read pixel data, to determine whether the image contrast of the read data is within a predetermined range, at block 404.

If "no" at test block 404, the process moves to adjusting block 406, where the light source .w intensity, for example, of the primary light source 2, is adjusted to obtain an acceptable image contrast in the next measuring cycle beginning at block 402, by the light source control circuits 35, at block 406. From block 406, the process moves to block 408.

.¾ > At block 404, should the image contrast be within a predetermined range, the process may continue to block 408. At block 408, the PLA 36 determines the yarn diameter, by processing the data from the pixels by, for example, a threshold method, such as binarizing the pixel data and counting pixels corresponding to the yarn 1.

From block 408, the process may continue to block 410, where determined yarn diameter value(s) for captured yarn segment image is/are stored in the microcontroller 30.

At block 412 it may be determined by the microcontroller 30, whether a history of the stored yarn diameter values (previously stored values) fail to meet a predertemined criteria for thickness (e.g., yarn evenness). If yes (fail detected), the yarn diameter is outside of an acceptable range for several consecutive measured yarn segments (for any number of o? predetermined segments designating a sample size of the like), e.g., too thin or too thick, and the l/O-lnterface 34 may send a yarn evenness alert A to the host system, at block 414. If criteria are met (the yarn diameter is within a predetermined thickness range) the process returns to block 402, from where it continues to read another pixel data. The return is also done, when the routine exits from Block 414.

The yarn evenness alert A is a result of monitoring the moving yarn for an acceptable range. When the monitoring from the measurement detects the yarn parameter is outside the given range, the A signal as an alert is produced.

"Blocks" as shown here may be functioning in a microcontroller software or a PLA

programmend function or as hardware coded elements. Blocks are mant to be read and understood as functions (and their inter-relation).

In FIG. 4B, yarn foreign fiber analysis and determination begins as pixel data, based on secondary light source 7 light reflected from the yarn, is read by the PLA 36, at block 452, for each yarn segment of a predetermined length. The PLA 36 then applies rules and policies to the read pixel data, to determine whether the image contrast is within a predetermined range, at block 454.

If "no" at block 454, the process moves to block 456, where the light source intensity, for example, of the secondary light source 7, is set to result in acceptable image contrast in the next measuring cycle, by the light source control circuits 35, at block 456. From block 456, the process proceeds to block 458. Also, at block 454, should the image contrast be within a predetermined range, the process also moves to block 458. At block 458, the PLA 36 determines RGB (Red-Green-Blue) color values (so called color analysis) for the yarn segment, for example, by processing light intensities of image sensor 3 pixels at specific positions relative to the position of the yarn image.

From block 458, the process continues to block (function) 460, where each determined RG B color value is stored in data memory associated with the microcontroller 30. It is then determined by the microcontroller 30, whether the history of the stored yarn RG B color values (currently and previously stored values) meets a predetermined criteria for foreign fibers, at function 462. If "yes", there are sufficient foreign fibers in the yarn 1 for several consecutive yarn segments to cause the l/O-lnterface 34 to send an foreign fiber alarm to the host system, at block 464. From block 464, or if "no", at block 462, the process returns to block 452, from where it continues. The alarm or alert signal A is the result of monitoring the yarn for the attirbute "foreign fiber present".

Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

The above-described processes including portions thereof can be performed by software, hardware and combinations thereof. These processes and portions thereof can be performed by computers, computer-type devices, workstations, processors, micro-processors, other electronic searching tools and memory and other non-transitory storage-type devices associated therewith. The processes and portions thereof can also be embodied in

programmable non-transitory storage media, for example, compact discs (CDs) or other discs including magnetic, optical, etc., readable by a machine or the like, or other computer usable storage media, including magnetic, optical, or semiconductor storage, or other source of electronic signals.

Claims

CLAIMS ...

1. Yarn quality monitoring device, the device comprising

a primary light source (2) for emitting light, a light propagation thereof

defining an optical path (100);

a diffuser (5) proximate to the first light source (2) for diffusing the emitted

light;

an image sensor (3) illuminated by the diffused light emitted from the

primary light source (2), for capturing a yarn contour image from

illumination of a moving yarn (1) in the optical path (100);

a focusing element (6) in the optical path (100) between the first light

source (2) and the image sensor (3), for focusing the yarn contour image on

the image sensor;

and a controller (4) in functional communication with the image sensor (3)

to process captured yarn contour image to provide measurements for a

yarn diameter of the moving yarn (1).

2. Device of claim 1, further comprising

a secondary light source (7) for illuminating the moving yarn (1), the reflected light propagation along a front portion of the optical path (100);

a diffraction element (8) in the front portion of the optical path (100), between the yarn (1) and the image sensor (3); the diffraction of light reflected from the yarn (1) from the secondary light source for interference pattern creation on the image sensor (3);

wherein the controller (4) is configured to process the interference pattern as well, to obtain a yarn color analysis.

3. Device of claim 2, wherein the diffraction element (8) is a diffraction grating.

4. Device of claim 2 or 3, wherein the primary light source (2) and the secondary light source (7) are designed to emit light at different wavelengths, and the device further includes an optical filter (9) at least partially covering the image sensor (3) for blocking light reflected from the yarn (1), when illuminated by secondary light source (7).

5. Device of one of claims 2 to 4, wherein the secondary light source (7) emits more light types, including one or more of monochromatic light, RGB-light, white light, UV-light or IR-light.

6. Device of one of claims 1 to 5, wherein the focusing element (6) includes one or more lenses selected from the group consisting of aspherical lens, mirror lens, convex lens and concave lens.

7. Device of one of claims 1 to 6, wherein the focusing element (6) includes one or more lenses in an M12x0.5 package.

8. Device of one of claims 1 to 7, wherein the image sensor (3) comprises one or more lines of photosensitive pixels, preferably the image sensor is of a CMOS-type sensor or a CCD-device.

9. Device of one of claim 1 to 8, wherein the image sensor (3) includes microlenses to limit wide angle light rays.

10. Device of one of claims 1 to 9, wherein the controller (4) comprises

a programmable logic array (36) for image data processing, to obtain

yarn diameter and/or yarn color analysis;

a light control circuit (35) in communication with the programmable logic

array (36) to be controlled by the programmable logic array (36);

and a microcontroller (30) in communication with the programmable

logic array (36), the microcontroller programmed to evaluate or mesure

a yarn eveness, and/or a yarn foreign fiber content, from the processed

image data.

11. Method of yarn quality monitoring, the method comprising

illuminating an image sensor (3) with light from a primary light source (2)

configured for creating a contour image of a moving yarn (1) on the image

sensor (3), the primary light source diffused by a diffuser (5) and focused by

a focusing element (6), on the image sensor (3), the primary light source,

diffuser and focusing element aligned to define an optical path (100);

obtaining a contour image of the yarn (1) by the image sensor (3), the

moving yarn positioned in the optical path (100) between the primary light

source (2) and the image sensor (3); and

processing the yarn contour image to obtain a diameter of the yarn (1).

12. Method of claim 11 further comprising:

illuminating the moving yarn by a secondary light source (7), such that the light from the secondary light source is reflected from the moving yarn (1);

focusing (6) the reflected light on the image sensor (3);

diffracting (8) the reflected light from the moving yarn to cause the creation of an interference pattern on the image sensor (3);

reading the interference pattern from the image sensor (3);

and processing of the interference pattern for obtaining a yarn color analysis.

13. Method of claim 12, wherein the secondary light source (7) emits at least one or more types of light including: monochromatic light, RGB light, white light, UV light, IR light, and combinations thereof, preferably a different light type than the primary light source (2).

14. Method of claim 12 or 13, wherein the illuminating by the primary light source (2) is at a wavelength different from a wavelength of light emitted from the secondary light source (7), and further

covering a portion of the image sensor with an optical filter (9);

passing the emitted light from the primary light source (2) through the optical filter covering the portion of the image sensor (3); and

blocking light reflected from the yarn, to cause illumination from only the primary light source (2) for measuring the diameter of the moving yarn (1).

15. Method of claim 14, wherein the capturing of the contour image of the moving yarn and the capturing of the interference pattern is performed simultaneously by the image sensor (3).

16. Method of one of claims 11 to 15, further comprising controlling (35) the primary light source (2) to emit light at an intensity based on processing results from at least one previously captured image from the image sensor (3), preferably in a feedback loop.

17. Method of one of claims 12 to 16, further comprising controlling the secondary light source (7) to emit light at an intensity based on processing results from previously captured image from the image sensor, preferably in a feedback loop.

18. Yarn quality monitoring device, comprising:

a light source (7) for illuminating a moving yarn (1);

an image sensor (3) positioned, to be illuminated by reflected light from the

light source (7), the light reflected from the moving yarn (1) and

propagating along the front portion of an optical path (100) to the image

sensor (3), the image sensor capturing image data;

a focusing element (6) positioned in the optical path (100) between yarn

and image sensor, for focusing the reflected light on the image sensor (3);

a diffraction element (8) positioned in the optical path (100) between

moving yarn (1), and image sensor (3), to diffract light reflected from the

yarn (1);

and a controller (4) for processing the captured image data to obtain a color analysis of the moving yarn and diameter data of the moving yarn (1) for

monitoring the yarn.

19. Device of claim 18, wherein the diffraction element (8) is a diffraction grating.

20. Device of claim 18 or 19, further comprising:

a further light source (2) for emitting a further light, the light propagation

defining a the optical path (100);

a diffuser (5) proximate to the further light source (2) for diffusing the

emitted further light;

the diffused light for illuminating the image sensor (3) along the optical path

(100) and through the focusing element (6) and the diffraction element (8); wherein the moving yarn (1) is placed as an obstacle in the optical path (100), to create a yarn contour image on the image sensor (3), to be

provided (3a) to the controller (4) for processing a yarn diameter

measurement or making a yarn diameter measurement.

21. Device of claim 20, wherein the light sources (7,2) are configured to emit light at

different wavelengths, and the device further includes an optical filter (9) at least partially covering the image sensor (3) for blocking the light reflected from the yarn (1) when illuminated by the light source (7).

22. Device of one of claims 18 to 21, wherein the light source (7) is arranged to emit one or more light types, including monochromatic light, RGB-light, white light, UV-light and IR- light.

23. Device of one of claims 18 to 22, wherein the focusing element (6) includes one or more lenses selected from the group consisting of aspherical lens, mirror lens, convex lens, concave lens.

24. Device of one of claims 18 to 23, wherein the focusing element (6) includes one or more lenses in an M12x0.5 package.

25. Device of one of claims 18 to 24, wherein the image sensor (3) comprises

one or more lines of photosensitive pixels; and the image sensor is of a

CMOS-type sensor or a CCD-type sensor (charge coupled device).

26. Device of one of claims 18 to 25, wherein the image sensor (3) includes microlenses configured to limit wide angle light rays.

27. Device of one of claims 18 to 26, wherein the controller (4) comprises:

a programmable logic array (36) for an image data processing to obtain

moving yarn diameter and/or moving yarn color analysis;

a light control circuit (35) in communication with the programmable logic

array (36), which is controlled by the programmable logic array; and

a microcontroller (30) in communication with the programmable logic array

(36), the microcontroller programmed to evaluate from the processed

image data a yarn eveness, and/or a yarn foreign fiber content.

28. Method of yarn quality monitoring comprising:

illuminating a moving yarn (1) by a light source (7) configured for creating

an interference pattern on an image sensor (3), the light source (7)

providing light reflected from the moving yarn (1) and diffracted by a

diffraction element (8) and focused by focussing element (6) on the image

sensor (3), the diffraction element and focusing element aligned to define

an optical path along which the reflected light from the source light

propagates when reflected off the moving yarn (1);

obtaining an interference pattern at the image sensor (3); processing the

interference pattern to obtain color analysis of the yarn (1).

29. Method of claim 28 further comprising:

passing of part of light reflected from the yarn through the diffraction

element un-diffracted;

capturing the focused un-diffracted light by the image sensor as yarn image;

and

processing the yarn image to determine at least one diameter of the yarn.

30. Method of claim 28 or 29, further comprising:

illuminating the image sensor with light from a further light source (2),

creating a contour image of the moving yarn (1) on the image sensor (3), the

further light source providing light diffused by the diffuser (5) and focused

by the focusing element (6), on the image sensor (3), the further light

source (2), diffuser and focusing element being in alignment to define an

optical path (100);

obtaining a contour image of the yarn (1) by the image sensor (3), the

moving yarn positioned in the optical path (100) between the further light

source (2) and the image sensor (3);

and processing the yarn contour image to obtain a diameter of the yarn (1).

31. Method of one of claims 28 to 30, wherein the light source (7) emits at least one type of light including: monochromatic light, RGB light, white light, UV light, IR light, and combinations thereof.

32. Method of claim 30, wherein the illuminating by the light source (7) is at a wavelength different from a wavelength of light emitted from the further light source (2), and further comprising:

covering a portion of the image sensor with an optical filter (9);

passing the emitted light from the further light source (2) through the

optical filter to a portion of the image sensor; and

blocking light reflected from the yarn, to cause illumination from only the

further light source (2) for measuring a diameter of the moving yarn.

33. Method of claim 30 or 32, wherein the capturing of the contour image of the moving yarn and the capturing of the interference pattern is performed simultaneously by the image sensor (3).

34. Method of one of claims 28 to 33 comprising controlling the light source (7) to emit light at an intensity based on processing results from a previously captured image from the image sensor, preferably in a feedback loop.

35. Method of claim 30 comprising controlling the further light source (2) to emit light at an intensity based on processing results from previously captured image from the image sensor, preferably in a feedback loop.

36. Device for measuring yarn parameter(s), the device comprising a controller (4) and

a programmable logic array (36) for image data processing, to obtain yarn diameter and/or yarn color analysis;

a light control circuit (35) in communication with the programmable logic array (36) to be controlled by the programmable logic array (36);

and a microcontroller (30) in communication with the programmable logic array (36), the microcontroller (30) programmed to evaluate or measure a yarn eveness, and/or a yarn foreign fiber content, from the processed image data.