JPH0364572A - Apparatus and method for discriminating extending thread on bobbin winder - Google Patents

Abstract

PURPOSE: To inspect yarn defect on the surface of a bobbin, especially rapidly inspect an elongated yarn by photographing a fan-shaped illuminated zone formed by making light rays strike on the surface of a bobbin so as to go past by the bobbin to give an image and analyzing the image by an image judging apparatus having a computer. CONSTITUTION: A bobbin 1 is placed on a turntable 12 rotatable by an engine 13, light rays are sent from a light source 10 which is substantially radial to the axis of the bobbin 1 and emits light rays to go past by the surface of the bobbin 5 and made to strike through a reflector 11 on the surface of the bobbin to form a fan-shaped illuminated zone. A photograph device having a built-in line sensor/interface 14 and a photograph lens 7 is used. An image line photographed by successively changing the position of the fan-shaped zone on the illuminated surface of the bobbin 5 by the rotation of the turntable 12 is filtered in a wide range, and the existence of an elongated yarn 2 is ascertained by an image judging apparatus by the computer to output a detecting signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an arrangement for illuminating at least one area of the front surface of a spool in order to identify surface defects, in particular stretched threads, on at least the front surface of said spool. , and a device for taking at least one image of the illuminated area;
The present invention also relates to an apparatus including one image determination device. The invention further relates to a method for identifying extended threads with such a device.

It is well known, for example from West German Patent DE-A-3630668, to use optical inspection methods to inspect wound bobbins for defects. The end surface of the reel is illuminated at a vertical angle in order to identify the stretching thread. This illuminated location is imaged onto an image sensor using a single conventional taking lens. The images are digitized and valued. However, in the meantime, this conventional image recognition method requires extremely complex calculations and a correspondingly long 31 calculation time in order to reliably identify the stretched thread.

This amount of time is too long to efficiently manage constant, ongoing production.

In view of the above-mentioned drawbacks, the task now arises to perfect the apparatus and method of the method mentioned at the outset. In this way, surface defects, in particular the presence of stretched threads, can be identified on a single screen of a spool quickly, i.e. immediately in response to the production operation, and also with a significantly reduced calculation effort. As a result, it becomes possible to carry out automatic quality control of the continuous production of winding the thread onto the reel.

This object is solved according to the invention by the features of claims 1 and 9.

By using a single cylindrical lens according to the invention, the possibility is created to identify extended threads more quickly. This is because most of the processing of data is done optically, and some simple processing is required when making image judgments.
11. This is because only the if'l operations are needed. In particular, the cylindrical lens achieves integration along the path of light, but the labor-intensive process of autopsy91 also comes to an end as a result of this. be.

First, let us explain in more detail the structure and function of the present invention with an embodiment in mind and with reference to the drawings. Each mouth represents the following:

Figure 1 is a diagrammatic drawing of the optical configuration using perspective drawing, and Figure 2 shows how the combination of one cylindrical lens and one circularly symmetrical lens functions. Fig. 3 shows the arrangement according to Fig. 2 as a perspective view from the side, and Fig. 4 shows the configuration according to Fig. 2. This is a perspective view from one side; FIG. 5 is a sacropalpebral view of the l'Iii surface of the reel, with a lens only roughly shown; and FIG. m according to FIG.
Figure 7 is a schematic drawing of a curved reflector used to illuminate the front side of the reel, and Figure 8 is a diagram of the luminous intensity prior to processing of the image data. This is a collection of 4 photos related to my profile.
Figure 9 shows the luminous intensity profile of the photograph and images composed of several photographs.
FIG. 0 is a three-dimensional sectional view showing the configuration of control logic and data processing logic.

One of the most dangerous defects that can occur when winding thread onto a spool is the occurrence of so-called stretched threads.

A stretched thread is a thread in which, when the thread is wound around a spool, a portion of the thread extends into the "nil" of the spool and appears in a kind of circular widening. When unwinding the yarn from such a defective spool, there is a risk that the thread will tear at the stretched yarn. This danger increases the greater the chord tangent angle that occurs (i.e., the greater the angle ψ between this stretched thread and the tangent to the line of progress of the circular ordinary thread at the point of occurrence of this stretched thread). (I see), it becomes increasingly large (see Figure 6). This angle ψ increases as the length of the stretched thread increases, and tanψ=L
/2r, the radius r relative to the center of the cup frame increases as it decreases. Stretching threads with a similar risk therefore form a sector of a circle with a turn opening angle in each case.

In accordance with the embodiment of the invention that has been described above, a sector 3 on the front side 5 of the reel ↓ is illuminated in order to locate the presence of a stretched thread. The incidence of the light rays 4 is radial with respect to the axis of the reel, but in particular, as can be seen from FIGS. It is possible.

A single stretched thread 2 in an illuminated fan-shaped area 3
appears in the picture of the enemy as a bright light before the horizontal movement of the circular thread in +'+ij 11i Table 1fri (see Figure 1). Now, above the illuminated sector 3, the integration of the luminous intensity changes perpendicularly to the radius R of the spool and at the position i of one spool (in this case 1 ft. (the elongated thread takes this direction), but in that case, the value of luminosity is
Along the stretch thread, it accumulates to a relatively high value, while in the vicinity of said stretch thread, bright and relatively dark spots alternate along the path of integration, thereby resulting in a smaller value. The result is that (lith 51 (the thread is
As a result, it appears as a peak in the radial luminosity profile, following a second integration.

This integration now takes place on the optical path in the case of the invention. In addition, in front of one photographing lens 7 in the illuminated fan-shaped area 3,
One cylindrical lens 6 is arranged.

Regarding the action of integrating this cylindrical lens in the - direction,
Let's discuss this in more detail based on Figures 2 and 3. This effect is due to the fact that the focal length of this cylindrical lens 6 is divided into two main directions. Along the longitudinal direction of this cylindrical lens, this cylindrical lens 6 acts like two flat plates. In other words, this cylindrical lens has no essential effect on the path of light rays (Figure 2). In the lateral direction of this cylindrical lens, this cylindrical lens acts like a single lens with a certain focal length (FIG. 3).

If an object g is imaged by the lens 7 into an image plane, this cylindrical lens, as it bends in its longitudinal direction (according to FIG. 2), follows the path of the ray. It has no effect on anything. In the lateral direction, on the other hand, the light rays striking this cylindrical lens are bent, resulting in a smudge in the image plane. Now, since various information from many target points partially overlap, an unifying effect occurs in this horizontal direction. As a result, various images of the illuminated fan-shaped area 3 are produced, as shown in Figures 8a to 8d (in each case, ``2''). , In these figures, the thread structure in the photographed area in the front appears as a striped pattern. Care must be taken that all horizontal rows of such an image contain approximately the same information (i.e. along the radius of one spool, in the direction of the elongated thread). (This means that it includes the integrated change in luminosity within the range.) For the characterization of the shooting, therefore, in each case
It is sufficient to further determine the value of such a sequence of images. For this reason, the taking lens 7 may also include only one sensor, with which each image sequence is taken.

In the lower part of each of the figures from FIGS. 8a to 8d, the corresponding luminous intensity development for such a column is illustrated. In Figures 8a and 8b, the presence of the elongated filament can be identified by a clear peak in luminosity at the location highlighted by the arrow, while in Figures 8c and 8d,
In the figure, regions that do not show the presence of extended threads are represented.

It can be seen that the peaks discernible therein are due to their non-uniformity and are corresponding to the illumination and the surface of the reel.

In order to obtain these images on purpose, in the embodiment described above, the taking lens 7 is retracted, so that the illuminated sector area 3 on the front side 5 of the reel is This results in a clear image. In front of this taking lens 7, in the radial direction of the reel, a cylindrical lens 6 is arranged in the path of the light beam. This does not affect clear imaging in the radial direction, but on the other hand, perpendicular to it, the integration effect mentioned above appears.

The images taken in this way (see FIGS. 8a to 8d), however, do not yet allow an unambiguous identification of the dangerous stretch thread. Because,
This is because other luminous intensity peaks will also appear due to the presence of an irregular front surface of the reel. Moreover, the influence of illumination becomes discernible as the luminous intensity increases outwards, ie with increasing radius.

This increase has the potential to be even greater than the maximum luminous intensity peak.

In order to eliminate this gradual fluctuation, the luminosity transition is
During the processing of the image data, it is subjected to high-pass filtering in the radial direction.

This is done by calculating the average value by appropriately shifting the course of the luminous intensity. For further value determination, instead of the luminosity at the negative point, the difference between the luminosity at that point and an appropriately shifted average value is then observed.

Thus, in this high-pass filtering, the luminous intensity X1 of each image point is converted into a single value.

1]+N (1i, 2 N + ) is the length (in number of image points) of the interval over which the luminous intensity is equalized by qL.

Further refinement of the formation of an appropriately shifted average by using a Gaussian function instead of a simple rectangular function, according to the formula given above, and determining the degree of importance of the image points <i 81 I can do it.

This high-pass filtering allows short peaks in luminosity to stand out clearly and unnaturally from gradual fluctuations.

1) Illumination of the area or fan-shaped area on the surface 5 of the winding frame 1 is carried out in order to obtain the high contour 1 to the lath 1- as intended. The grazing incidence primarily illuminates the overlying elongated threads;
As a result, these stretched threads stand out as bright lines from the front. As shown in FIG. 4, the beam is therefore cut using the reflector 11, 11':
(It is guided from i Q and appears as a tangent that brushes over the Mif surface 5 or touches ^jl ?IQ 'll71. If this front surface is bent, the best shape of reflection is , formed by a correspondingly curved reflector 11' on its front surface, which is illuminated by parallel rays (as shown in FIG. 7). ).This best form of reflection is anyway achieved approximately according to FIG. This approximate achievement can be justified by the fact that the reel usually does not have a clearly defined contour.

In order to further increase the contrast 1-lase 1, illumination or imaging can be carried out, with the result that the area 8 in the middle of the imaged sector 3 remains open (6th
(see figure). In this intermediate region, the elongated threads extend in one row relative to the orderly thread structure (this becomes clear from Fig. 6). ). Therefore, even if we accept the existence of this realm, it will contribute almost nothing to the contrast that we have been striving to obtain; Allowing their existence would lead to an increase in the noise figure. This intermediate area 8 gradually fades to 1
As a result, this intermediate region is either not illuminated or is illuminated by preparing a corresponding burn mark in the path of the light ray of the photographic lens 7. .

Up to this point in this specification, we have each started from the idea of trying to grasp the sector shape of a single point on the front side of a reel using a graph, but after this, in practice,
The entire front surface must be searched for unacceptable tension threads. For this purpose, gradually several images at various angular positions ψ of the reel are taken until the entire front surface is captured. At that time, the reel frame is set for each shooting.
In each case, for example Δψ=2° relative to the axis of the reel.
You can change direction in 1 degree or less.

Since the stretched thread is a straight thread (the thread extends perpendicular to the radius of the reel), when photographed, the stretched thread is moved by the cylindrical lens 6 at this angular position i.
Only some parts of ll: are made to look like l''. We can now make this property useful by composing each row of shots into a new image. As is evident in Figures 9a and 9c, each column of this image has a constant angular position ψ. It is representative of the Along this row, the pictorial elements record a radial intensity profile (as if this intensity profile had been photographed at the angular position in question and in the manner already described).
, it's raining. Figures 9a and 9c show a 100"-section of the reel, ie 50 rows with an angular displacement of Δψ=2° in each case. One such image The picture element at the break r0 corresponds to the shift of the luminous intensity along a circle with a corresponding radius r on the front side of the reel.

Among the directions ψ of the cracks in the image, the contrast 1 ~ is now calculated by using the above-mentioned transformation with an appropriately shifted early mean f-square,
It can be enhanced. FIG. 9c shows an image constructed according to FIG. 9a (according to this transformation with respect to the position of the 11 reels). Along a certain row, i.e. at that angular position (at which angular position one stretched thread was in the illuminated sector), each time the lower 9b The luminous intensity course represented in the figure and in FIG. 9d shows the increase in contrast due to this transformation.

Transformation or high-pass filtering in the direction ψ of the constructed image has further advantages.

This has the advantage that smaller defects in the surface of the bobbin (such as grooves or bulges that would not be considered defects in the bobbin) can be distinguished from the stretched thread. Such a narrow groove extends over a larger angular area of the bobbin than the tension thread and thereby appears as a peak in luminous intensity at some angular position. Therefore, the influence of such a narrow structure can be reduced by a high-pass filter in the direction ψ of the constructed image, if the area for forming the average (n'f) is chosen relatively small without any deviation. It is weakened by change.

The search for the stretched thread in the bobbin 1 is carried out in accordance with the details given above and as follows. The reel to be examined is placed on a rotary table 12. In addition, preplanned automatic devices are not a subject of the present invention and will not be described in further detail here. This rotary table 12 is
The engine 13 and the engine control head ↓7 (this device is combined with a computer) are rotated gradually or sequentially (see Figure 10), in which case the engine is equipped with a row sensor. Using a video camera or line camera 14, a series of images is taken in a known manner. This image column consists of one column server 19 20 server interface 14 and one computer bus 1.
6 into the computer 15, where the data is stored in the storage device vl. In the calculator 15, a high-pass filtering especially takes place in two dimensions ψ and R of the constructed image. A dangerous stretched thread is identified if a luminous intensity peak exceeding a certain limit value appears in the converted image. This activates a signal on the computer bus for operation of the automatic sorter, by means of which defective reels are separated. Furthermore, a corresponding notification can be made.

By taking this measure as described, essentially aJ
A total of 5% labor savings can be achieved. We are 256×256
Starting from the size of the constructed image ψ,R with image points, -microprocessors-
When using 8086 (Intel), it takes about 6 seconds to 7 seconds.
It turns out that it takes several seconds of calculation time.

As evident in Figure 10, this device:
It is combined with a device for optical reel identification, with which the examined reel is identified. In addition to this, one camera 17 and one standard image storage device 18 have been pre-planned in a known manner, using which
Identification features are identified and classified.

The optical range of the above-mentioned arrangement can be formed sufficiently well, so that by photographing not only one sector 3 in front of the reel, but also two sectors facing each other at the same time are detected. It will also be recorded. In addition to this, grazing illumination is carried out on the two side diameters and two cylindrical lenses are accordingly planned in advance. Using one row sensor, an image is then taken over the entire diameter of the reel, the central image point being of course taken into account when determining the value. do not have.

With this arrangement, the reel on the rotary table 12 is only rotated by 180° [I+1, but as a result,
The entire front surface of this reel can be captured.

The gradual darkening of the intermediate fan-shaped area described above using FIG. Due to the partial fan shape, one cylindrical lens
It is prepared and installed in advance.

These two cylindrical lenses, which are placed parallel to each other, then each image a partial fan shape on the imaging device.

As is clear from the explanation in Section 2, according to the present invention, the calculation time for image determination is significantly reduced by the appropriate use of one or more cylindrical lenses in the path of the rays. As a result, inspection of the spool for flaws on the front surface of the spool can be done with an acceptable amount of effort.
This can be done during the manufacturing process, and defective spools can be inspected (and then visually inspected for manufacturing errors).
X, can be excluded from J.

[Brief explanation of drawings]

The upper figure is a diagrammatic drawing of the optical configuration drawn using the perspective drawing method, and the second figure shows how the combination of one cylindrical lens and -8 pairs of shield rings functions. Looking down 1
Figure 3 is a side view of the arrangement according to Figure 2, Figure 4 is a view from one side of the arrangement according to Figure 1, and Figure 5 is a rough view of the arrangement according to Figure 1. 6 shows an overhead view of the front of the reel with a lens only shown schematically in FIG. 6, according to FIG. Fig. 7 is a schematic drawing of a bent reflector used to illuminate the front side of the reel; Fig. 8 is a schematic drawing of the image data processing
The 9th question is to find the luminosity profile of the images composed of the images 3, 4, and 1, /II. The first LOM is a three-dimensional cutaway diagram showing the configuration of the control logic and data processing logic. L... Reeling frame, 5... I'+ij side of the reeling frame, 6, 7.
...Photographing lens, 8...Fan-shaped intermediate area, 1o.Light source, 11°11'...Reflector, 12.Rotary table,
13.Engine, 14...column sensor interface, J, 5"' jl calculator.

Claims (1)

Claims: 1. An illumination device (10) for creating an incidence of light rays extending substantially radially with respect to the axis of the bobbin (1) and grazing on the front surface (5) of the bobbin (1). , 11), at least one cylindrical lens (6), and one imaging device (7, 14)
optical devices (6, 7, 14) having
7, 14) in the optical path between one image plane (b) and one spool of thread (
1) a device (10, 11) for illuminating at least one area of said front surface, in order to identify surface defects, in particular stretched threads, at least on said front surface, and at least one device (10, 11) for said illuminated area; A device for identifying a stretched thread on a spool, characterized in that it comprises an optical device (6, 7, 14) for taking an image of the thread, and one image determining device. 2. Device according to claim 1, characterized in that the images taken correspond substantially in each case to a sector-shaped area (3) of the front surface (5) of the reel. 3. Device according to claim 2, characterized in that a central, fragmentary part (8) of the sector is covered or darkened during the imaging. 4. Cylindrical lens (6) illuminated area (3)
and the imaging device (7, 14), in such a way that the image axis defined by the illumination direction extends substantially into the longitudinal axis of the cylindrical lens. An apparatus according to any one of claims 1 to 3. 5. The image judgment device (
Claim 1 characterized in that it can be stored in
5. The device according to any one of items 4 to 4. 6. has a device (12, 13) for progressively optically examining the entire front surface of the reel, in which case the image taken is
Image judgment is based on the radial luminous intensity transition, which can be expressed as an image sequence by changing the position by a certain angle (Δψ) around the axis of the reel with each step, and being photographed and optically integrated with each step. 6. Device according to any one of claims 1 to 5, characterized in that it can be stored in the device. 7. Device according to claim 6, characterized in that the step angle (Δψ) is at most 4°. 8. A computer for locating the disturbance produced by the stretched thread in the photographed images, as well as an output device (16) for generating a signal according to the answer or a corresponding notification, in the image evaluation device (15). ) The apparatus according to any one of claims 1 to 7, characterized in that the apparatus comprises: 9. To weaken monotonous local luminosity fluctuations,
A device according to any one of claims 5 to 7, characterized in that the radial luminosity profile represented in an image sequence is subjected to a high-pass filter. Using a method for identifying stretch threads. 10. The method according to claim 9, characterized in that high-pass filtering is carried out by forming an average value of the luminous intensity transition suitably shifted and a subtraction of the luminous intensity transition from the original image. . 11. In order to form a suitably shifted average value, the detailed image points are processed according to a numerical undetermined function, in particular a Gaussian function,
11. The method according to claim 10, characterized in that: 12. The photographed image is characterized in that the image composed of the image sequence is subjected to high-pass filtering along the angular axis of the image.
Step by step, the position of the reel is changed by an angle about the axis of the reel, and with each step a radial luminous intensity course can be memorized, which can be represented as a sequence of images, so that the entire front surface of the reel gradually becomes optically visible. 11. A method according to claim 9 or claim 10, characterized in that the method is characterized in that the method is used to investigate