WO2014029038A1

WO2014029038A1 - Characterization of an optoelectronic measuring unit for textile material to be inspected

Info

Publication number: WO2014029038A1
Application number: PCT/CH2013/000147
Authority: WO
Inventors: Kay-Uwe Kirstein; Norbert Ziganek; Rafael Storz
Original assignee: Uster Technologies Ag
Priority date: 2012-08-20
Filing date: 2013-08-20
Publication date: 2014-02-27

Abstract

The invention relates to a method which is used to characterize an optoelectronic measuring unit (1) for textile material to be inspected, which unit having an optical path for measuring light (17) used during measuring. A substantially flat test specimen (2), which is neither a copy or an imitation of the material to be inspected is introduced into the optical path. The test specimen (2) is measured by means of the optoelectronic measuring unit (1). This allows the optoelectronic measuring unit (1) to be characterized and/or adjusted more easily and more comprehensively than previously.

Description

CHARACTERIZATION OF AN OPTOELECTRONIC MEASURING UNIT

FOR A TEXTILE TESTING MATERIAL

TECHNICAL AREA

The present invention is in the field of textile material testing with opto-electronic means. It relates to a method for characterizing an optoelectronic measuring unit for a textile test material, according to the preamble of the first claim. Furthermore, the invention relates to a combination of an optoelectronic measuring unit for a textile test material and a substantially planar test pattern according to a further independent Patentanspmch. In addition, the invention also relates to an optoelectronic measuring unit for a textile test material, according to the preamble of another independent claim.

The optoelectronic measuring unit, to which the invention relates, is used for. As for the optoelectronic testing of textile fibers, sliver, roving, yarn, knitted fabric and / or tissue.

STATE OF THE ART

For the detection of properties of a textile test material, for example a yarn, opto-electronically measuring test devices are used. According to the basic principle of the optoelectronic measurement, the textile test material is illuminated by a light source, and a part of the light, which has interacted with the textile test material, is detected by means of a light detector. On the basis of an output signal of the light detector, properties such as diameter, hairiness or

Foreign substance contamination of the textile test material can be determined. The following documents give examples of text ile Prüivorriehtungen, each one

Optoelectronic measuring unit includes: US-A-6,052,182 A for fibers.

WO-201 1/153648 AI for yarn and WO-2005/085813 AI for fabric. Different devices basically measure differently due to device-specific measurement errors, especially if the device is distended towards its measuring limits. It is therefore to be expected with differences between the actual value and the measured value and thus also with different measurement results between different, the same measurement performing devices. From a certain deviation (measurement error) action is required because the functionality and / or accuracy is not sufficient.

It is known from the prior art to calibrate or adjust an optoelectronic yarn cleaner before the actual measurement on the yarn. This is done by means of

Measurements on a reference body or caliber that is as similar as possible to the yarn. Thus, US-6,659,386 Bl uses a reference thread and the

ΕΡ-Γ028'305 A2 a thin rod. DE-101'59'153 AI uses either a standard thread or alternatively a glass substrate on which a black circle is printed. The active sensor surface covers only a small portion of the black circle, so this section simulates a yarn. From the black circle go from branches, which simulate the hairiness of the yarn; When the glass substrate rotates, a dynamic calibration of the optically operating Gamreiniger can thus also take place.

PRESENTATION OF THE INVENTION

It is an object of the invention to provide a method which allows in a simple manner to characterize and / or adjust an optoelectronic measuring unit for a textile test more complete than before. Another object is to provide an optoelectronic measuring unit that is simple and complete

characterize and / or adjust.

These and other objects are achieved by the inventive method and the inventive measuring unit, as defined in the independent claims. Advantageous embodiments are specified in the dependent claims. The inventors have recognized that it is not necessary to concentrate on the textile test material to solve the problem by providing a comparison body that is as similar as possible to the textile material or that imitates it in an idealized form. Instead, the attention of the optoelectronic measuring unit itself or the optical system contained in it should apply. After all, it is the optical properties of this system that are to be characterized. Consequently, it may be advantageous, instead of a comparison body that simulates the textile material to be tested, to use an abstract test pattern that is neither an image nor an imitation of the test material. The

Test pattern is optimized to optical properties of the optoelectronic

To characterize the measuring unit as simply and completely as possible.

The test pattern should therefore differ visually from the test material. Preferably, it is an abstract, synthetically generated test pattern. The test pattern may be similar or partially even designed as the known test images for

Assessment of picture quality of TVs and screens. It can also be referred to as an "optical diagnostic tool." The test pattern can be used in transmission and / or reflection, depending on the intended mode of operation of the optoelectronic measuring unit It is fundamentally possible for different and accessible measuring parameters to be accessible via the optoelectronic measuring unit In principle, it is desirable to have as many as possible adapted test patterns to be measured

Cover measurement parameters with a single test pattern; However, under certain circumstances, this can lead to losses in the measurement accuracy and finally to inaccuracies in the characterization or adjustment, so that it may be expedient to use a plurality of different test patterns for different measurement parameters.

The test pattern is introduced into an optical path of the optoelectronic measuring unit. The optical path is the region of the optoelectronic measuring unit which, when used in accordance with the measurements taken with the optoelectronic measuring unit, will be traversed by the measuring light which is used to carry out the measurements. The optical path includes a measuring field, which serves to receive the textile test material and in which the intended optical measurements are carried out on the textile test material. The test pattern can be inserted into the measurement field or outside it become. It can during the inventive process with respect to the

stand still or moving optoelectronic measuring device.

The inventive method is used to characterize an optoelectronic measuring unit for a textile test material, which has an optical path for measuring light used in measurements. A substantially flat test pattern, which is neither an image nor an imitation of the test material is introduced into the optical path, and the test pattern is with the optoelectronic measuring unit

measured.

In one embodiment, at least one quality value is generated from the measurement, the quality value is compared with a corresponding predetermined target value in terms of quality, and a result of the comparison is output. For this purpose, in a first alternative, at least one test pattern measured value for at least one measuring parameter is generated from the measurement, and the quality value is set equal to the testmeasurement value. In a second

Alternatively, at least one test pattern value for at least one measurement parameter is generated from the measurement, a measurement target value for the test pattern value is specified, and a mathematical combination, preferably a difference and / or a quotient, is formed between the test pattern value and the nominal value in the calculation of the quality value. The measurement parameter can be measured several times, an average over the several measurements formed and the Testmustennesswert this mean

be equated.

In one embodiment, at least one test pattern result is generated for a plurality of different measurement parameters. In a first alternative will be for everyone

Measurement parameter generates its own quality value. In a second alternative or in addition, a single total quality value is generated from the plurality of measurement parameters.

In one embodiment, a tolerance range is assigned in advance to the quality setpoint corresponding to the quality value. The comparison is to determine whether the quality value is in the tolerance range or not. The result of the comparison is different, depending on whether the quality value is within the tolerance range or not. If the method according to the invention provides a quality value deviating greatly from the setpoint value, then a result of the comparison is indicated, which indicates poor quality and thus action required, such as repair. It is thus possible, for example, for the optoelectronic measuring unit to carry out the method according to the invention automatically and / or by an operator after predetermined intervals

Operator then at most indicates the need for action. There may be a need for action if, for example, an image sensor, a light source, an optical system or other elements are defective or poorly adjusted or aligned, so that bad

Measurement results are supplied by the optoelectronic measuring unit. If the method according to the invention shows that the optoelectronic measuring unit measures well and delivers quality values which are at least predetermined close to the target quality value or within a tolerance range, certain quality standards are met. For example, high goodness may be associated with a higher number such as "10" or a letter that appears early in the alphabet, eg, "A", then poor goodness may, for example, have a lower number such as "1" or a lower case Alphabet following letters, eg "E". This number or letter is then the assigned quality value. However, the quality value can also be assigned in another manner known to the person skilled in the art, for example by means of a graphical representation. The test pattern is preferably such that at least one optical property of the optoelectronic measuring unit can be characterized by means of the test pattern. The at least one optical property can be selected from the following set: sharpness, resolution, contrast, brightness, color saturation, image position, geometry, imaging scale, image trimming. The test pattern can be subdivided into several subareas, so that the same optical property can be characterized at different locations of the test pattern and / or different optical properties can be characterized. In one embodiment, the test pattern includes a holographic structure.

For example, the test pattern may be prepared by etching a film, a glass substrate, or a layer coated on a glass substrate. A person skilled in the art knows how to treat, for example, a transparent film, another transparent planar element or a layer applied to such an element by etching in such a way that certain regions are so transparent with respect to light transmission or transparency be changed, that a test pattern is created. It is also advantageous if the test pattern for easier handling, for example. Has a stable, at least partially surrounding the test pattern edge, preferably made of a stable material such as plastic or metal, this edge advantageously as protection for the enclosed therein test pattern and / or as a mounting area for the introduction serves. The attachment region may have fastening means such as detents, clamping or screwing means or the like for fixing the test pattern in the measuring field.

The test pattern may be introduced into the optical path either manually by an operator or automatically by a loader. In the latter case, the introduction is preferably carried out by means of a telescopic Anns, an extendable Anns and / or a Schwenkanns.

The optoelectronic measuring unit preferably has a measuring field for the textile test material. In a first variant, the test pattern is introduced into the measuring field instead of the textile test material. The test pattern can then fill in substantially the entire measurement field. In a second variant, the test pattern is introduced outside the measuring field in the optical path. In one embodiment, the test pattern is moved during its measurement. The movement is z. B. a shift and / or a rotation.

Due to the characterization of an adjustment of the optoelectronic measuring unit can be made. The term "adjustment" is understood in this document to mean adjustment or adjustment of the optoelectronic measuring unit with the aim of

to eliminate systematic errors as far as possible.

The invention can serve for the identification of faulty optoelectronic measuring units. The inventive method can, for example, in the final test of a

optoelectronic measuring unit after its manufacture or carried out after maintenance or service work. On the basis of the characterization obtained in the said method, it is then possible, for example, to have a clearance for sale or a conclusion of the maintenance work, or it can be a appropriate adjustment of the optoelectronic measuring unit can be made.

Alternatively or additionally, the method according to the invention can be carried out during the operation of the optoelectronic measuring unit, for. B. between two measurements. In this case, triggers for carrying out the method may be a predetermined number of measurements, a predetermined time interval or indications of a malfunction.

The invention also includes the use of a substantially planar test pattern, which is neither an image nor an imitation of a Pmfgutes, for

Characterization of an optical measuring unit for a textile test material.

Furthermore, the invention comprises a combination of an optoelectronic measuring unit for a textile test object, which has an optical path for measuring light used in measurements, and a substantially planar test pattern, which is neither an image nor an imitation of the test material and which can be introduced into the optical path ,

The optoelectronic measuring unit according to the invention for a textile test object has an optical path for measuring light used in measurements. Further, it includes a substantially flat test pattern, which is neither an image nor an imitation of the Pmfgutes, and a loading device for automatically introducing the test pattern in the optical path. The introduction device is z. B. as a telescopic arm, designed as retractable Ann and / or as Schwenkann.

It should be pointed out here that the optoelectronic measuring unit before carrying out the inventive method in an additional

Preparing step is prepared with an evaluation algorithm to a measurement of the test pattern and then converted by introducing the test pattern. Therefore, it is not necessary to use the algorithm used in the intended measurement, but it can be adapted to the test pattern, for example by offsetting the

Electronics in a diagnostic state switched algorithm for the

erfmdungsgemässe method can be used. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below with reference to FIGS

Drawings described are merely illustrative and not restrictive to interpret.

FIG. 1 shows an optoelectronic measuring unit according to the invention in one

schematic side view.

FIGS. 2-5 show various exemplary embodiments of test patterns for use in the method according to the invention.

FIG. 6 shows an optoelectronic measuring unit in the same view as FIG. 1 for illustrating further embodiments of the invention

Process.

DESCRIPTION OF PREFERRED EMBODIMENTS

Figure 1 shows schematically an embodiment of an inventive

Optoelectronic measuring unit 1, which corresponds in its optical structure substantially to that of Figure 3 of WO-201 1/153648 AI. The optoelectronic measuring unit 1 includes a lighting part and an imaging part. The

Lighting part has at least one light source 11 and an illumination optical system 12. As a light source 1 1 z. B. a light emitting diode (light emitting diode, LED) can be used. The light source 1 1 emits electromagnetic radiation 17 in the visible, in the rarer and / or ultraviolet spectral range, which in this document is summarized under the term "light" for the sake of simplicity

Illumination optics 12 collimates the light 17 emitted by the light source 1. In the illumination part, preferably the Köhl illumination is used, which is well known from the field of microscopy and will not be discussed further here. The imaging part has an imaging optics 15 and an optoelectronic image sensor 16. The imaging optical system 15 images an object plane 13 onto the image sensor 16. The

In the example of FIG. 1, this is done in transmission, ie without any object in the object plane 13, the light source 1 1 illuminates at least one area of the image sensor 16, and if an object is inserted into the object plane 13, it at least shades a portion of the light 17 and / or changes its phase. The image sensor 16 is preferably a two-dimensional image sensor 16 having a multiplicity of picture elements (pixels) arranged in the form of a matrix. Such image sensors 16 are commercially available in the form of integrated optoelectronic components in various technologies, for example, from digital cameras well known and widely used. Alternatively, as the image sensor 16, a likewise known one-dimensional line sensor with a multiplicity of pixels, which are arranged on a straight line perpendicular to the gambling direction, can be used. In another alternative is not an image sensor, but a simple intensity sensor such. B. a photodiode used. For the sake of simplicity, the illumination optics 12 and the imaging optics 15 are shown in FIG. 1 as simple lenses; Of course, however, more complex optical systems can be used which, in addition to lenses, contain further optical elements such as diaphragms or filters. The invention is not limited to optoelectronic measuring units 1 with a construction according to FIG. 1, but relates to any optoelectronic measuring units.

Since the light 17 is used for carrying out measurements with the optoelectronic measuring unit 1, it can be referred to as "measuring light." The measuring light 17 defines an optical path in the optoelectronic measuring unit 1. When performing measurements according to the standards with the optoelectronic measuring unit 1 a textile test object, for example a yarn, are located in the object plane 13 and would be illuminated there by the measuring light 17, as shown for example in FIG

WO-201 1/163648 AI is shown. The longitudinal axis of the Gams would be in the representation of the present Figure 1 perpendicular to the plane. In this state, the optoelectronic measuring unit 1 would perform at least one optical measurement on the textile test material. Therefore, in the exemplary embodiment of FIG. 1, the illuminated and imaged part of the object plane 13 is referred to as "measuring field" 14.

In the inventive method for characterizing the optoelectronic

Measuring unit 1, instead of the textile test material, a test pattern 2 is introduced into the measuring field 14 and measured with the optoelectronic measuring unit 1. The introduction of the test pattern 2 i the measuring field 14 can be done manually by an operator or automatically by a loading device 18. The introduction device 18 is in Exemplary embodiment of Figure 1 designed as a telescopic or retractable Ann. The introduction of the test pattern 2 into the measuring field 14 or its removal from the measuring field 14 is indicated by a double arrow 19. Further examples of

Insertion devices that can also be used in the present invention are given in DE-101 '59' 153 A I.

The test pattern 2 is substantially planar, and its plane substantially coincides with the object plane 13 of the optoelectronic measuring unit 1. It is neither an image nor an imitation of the textile test material. When the optoelectronic measuring unit 1 operates in transmission, as in the example of FIG. 1, the test pattern 2 consists of more or less light-permeable areas, ie. H. Points, lines, surfaces, etc., and / or from at least partially transparent areas, which change the phase of the light transmitted through them differently. When the optoelectronic measuring unit operates in reflection, the test pattern consists of more or less reflecting areas and / or of at least partially reflecting areas, which are arranged at different heights above the object plane. Figures 2-5 show some embodiments of test patterns 2-5 for use in the

inventive method. A first exemplary test pattern 2 is shown in FIG. It is a checkerboard-like arrangement of, for example, square partial surfaces, which are each filled with one of a plurality of mutually parallel lines existing grid. There are two different types 21, 22 of subareas, with the grid lines running horizontally in one type 21 and vertically in the other type 22. This test pattern 2 can be used to characterize the sharpness, the position of the image, the geometry and the

Serve picture scale. Thanks to the division into several sub-areas, it is possible to make location-dependent statements about the above properties. The

Lattice constant may be the same in all faces, or it may vary from face to face.

Another test pattern 3 which can be used in the method according to the invention is the Siemens star 31 shown in FIG. The Siemens star 31 is a circular area with a variety, for example. 72, alternately white and black circular sectors. It is known per se and is usually used for testing cameras or screens.

The test pattern 4 of FIG. 4 has in the left and middle part color bars 41 - 46, for example with the colors red 41, green 42 and blue 43 as well as cyan 44, magenta 45 and yellow 46. These can be used to characterize the color detection. In addition, in the right part of the test pattern there is a gray scale 47 with different gray values for characterizing contrast and brightness. Figure 5 shows hinted and only very schematically a test pattern 5 with a holographic structure fish 51. The holographic structure 51 is such that certain properties of the optoelectronic measuring unit 1 can be checked in the reconstruction of the hologram by illumination with the illumination part. A simple example of a holographic structure 51 is a Fresnel zone plate, i. H. the hologram of a point light source. Even with such a simple hologram, the optoelectronic measuring unit 1 can be characterized, for. B. in terms of sharpness and geometry. The holographic structure 51 is preferably computer-generated. For use in the optoelectronic measuring unit 1 according to Figure 1 is a

Transmission hologram required, and the light source used 1 1 must be coherent, for example. A laser light source. For optoelectronic measurement units that work in reflection, it requires reflection holograms, which can also be reproduced with incoherent light sources.

Another example, not shown in the drawings, of a test pattern suitable for use in the present invention is a diffuser or diffuser.

The test patterns discussed above are merely simple examples. Further test patterns suitable for use in the invention are known per se, for example from test images for assessing the image quality of television sets and screens. The above

Examples discussed and / or other test patterns can be combined into new test patterns. These can have partial areas with different partial test patterns, whereby the partial test patterns can also overlap. The test pattern can be z. B. square, rectangular, circular or other Fonn. Its dimensions can z. B. between 5 mm and 100 mm. In a

preferred embodiment is a square with a side of

15 mm.

In the method according to the invention, the test pattern 2 is introduced into the measuring field 14 and measured with the optoelectronic measuring unit 1. It is advantageous to generate at least one test pattern measured value from the measurement and to compare the test pattern measured value with a corresponding preset measured setpoint value. From the comparison, the optoelectronic measuring unit 1 can be assigned a quality value which numerically characterizes the optoelectronic measuring unit 1. The following is a simple example of this.

In one embodiment, the Siemens star 31 of FIG. 3 is used as the test pattern 3. The Siemens St ern 31 is through the imaging optics 15 to the image sensor

16 pictured. The image sensor 16 takes the corresponding image and sends it in digital form to a (not shown) evaluation unit. The evaluation unit evaluates the image by means of digital image processing. The Siemens star 31 is known to be the absolute resolution

£ = ndjn, where d is the diameter of the gray disc in the middle of the Siemens star 31, and n is the number of circular sectors. Suppose that a resolution of C = 0.125 mm is measured. That's how you get on

Resolution ratios U = 1 / t = 8000 m ^"1. This resolution U is in the

present example, the test pattern reading. It comes with a predetermined

Measuring setpoint of eg. U * = 10Ό00 f ¹ compared. A quality value Q of

Optoelectronic measuring unit 1 is defined as the relative deviation of the

Test pattern measured value U from the measuring setpoint U *:

Using one or more predetermined tolerance limits can be defined fin ^¬ the Q value, a tolerance range. Measuring units with a quality value Q within the tolerance range are sufficient, while measuring units with a quality value Q outside the tolerance range are insufficient, ie require repair, readjustment, etc. In the present example, the tolerance range is the set of all quality values Q for which Q> -0.1 holds. The quality value Q = -0.2 of the optoelectronic measuring unit considered here lies outside this tolerance range, so that the measuring unit is insufficient. With knowledge of the invention, one skilled in the art will be able to apply and / or generalize the above simple example to other test patterns. Some alternatives, special cases and / or generalizations are briefly discussed below.

In order to calibrate a higher statistical significance, it is possible, under unchanged conditions, to measure several, for example 10, 100 or 1000, test pattern values and to statistically evaluate the measurements. Such statistical evaluations could, for example, include the calculation of an average value and a standard deviation. The middle value can be used instead of the test pattern value in the calculation of the quality value, as well as the standard deviation and / or other statistical quantities.

The quality value may be a relative deviation from the target value (as in the example above), an absolute deviation, a quotient or any other mathematical combination of the test pattern value, the target value and, if required, other quantities. Alternatively, the quality value may be equal to the test pattern value itself or a statistical quantity derived from a plurality of test pattern values, such as. B. be an average.

Several different test pattern values can be measured on a single test pattern or, successively, on several different test patterns. Each of these test pattern measured values can then be individually compared with a corresponding desired value, and from each of the comparisons a corresponding quality value can be calculated and assigned to the optoelectronic measuring unit 1, so that the measuring unit 1 is characterized by several quality values for different parameters. Alternatively or additionally, it is possible to use the aforementioned plurality of quality values

mathematically linked to a single overall quality value. In this case, the mathematical combination can make a weighting of the different quality values, depending on the importance of the corresponding parameter.

FIG. 6 shows an optoelectronic measuring device 1 according to the invention in the same way as FIG. 1. In FIG. 6, however, the test pattern 2 is located outside the object plane 13 and thus outside the measuring field 14. (A test pattern in FIG

Measuring field 14 is shown by dashed lines for comparison.) Such an arrangement can, for. B. serve to characterize the properties of the optoelectronic measuring device 1 for the case in which the textile test material is not exactly in the measuring field 14. So z. B. a gradient of the quality value can be determined in the direction of the optical axis. If necessary, a location-dependent correction or adjustment can be determined and made from such a characterization. The test pattern 2 may be displaced out of the measuring field 14 into one or the other half space defined by the object plane 13, which is indicated by a double arrow 28. But it does not take an immediate shift out of the measuring field 14, but the

Test pattern 2 can be introduced directly from the outside to its destination outside the measuring field 14.

Alternatively or in addition to the axial displacement 18, the test pattern 2 can be displaced perpendicular to the optical axis, as indicated by the double arrow 29 in FIG. This can be z. B. be useful for characterizing the location dependence within the object plane 13.

The shifts 28, 29 of the test pattern 2 shown in FIG. 6 are static according to an embodiment. H. the test pattern 2 is held in its position, and in this state at least one measurement is performed with the optoelectronic measuring unit 1. According to another embodiment finds a dynamic

Characterization taking place. In this case, the measurement is made on the test pattern 2 during its displacement 28 and / or 29. Thus, the dynamic behavior of the

optoelectronic measuring unit 1 are characterized. The displacements 28, 29 can be performed by means known per se, for which the in FIG drawn insertion device 18 is exemplary. The displacements 28, 29 can take place once or periodically, slowly or quickly.

In addition to the displacements 28, 29 described above, according to the invention other congruence maps of the test pattern 2 are also possible, in particular rotations of the test pattern 2. In this case, the axis of rotation may lie in the object plane 13 or outside it. In a special case, the axis of rotation is perpendicular to the object plane 13 and the test pattern 2 in the object plane 13. The present invention is not limited in its execution to the above-mentioned preferred embodiments or embodiments. Rather, a number of variants is conceivable, which of the solution shown at

fundamentally different types of use. All from the

Claims, the description or the drawings resulting features and / or advantages, including design details, spatial arrangements and

Process steps can be essential to the invention, both individually and in the most diverse combinations.

5 LIST OF REFERENCE NUMBERS

1 optoelectronic measuring unit

1 1 light source

12 illumination optics

13 object level

14 measuring field

15 imaging optics

16 image sensor

18 introduction device

19 Introduction and removal of the test pattern

2 test patterns

21, 22 types of faces

28 axial displacement

29 orthogonal shift

3 test patterns

31 Siemens Stera

4 test patterns

41 red color bars

42 green color bars

43 blue color bars

44 cyan color bars

45 magenta color bars

46 yellow color bars

47 gray stairs

5 test patterns

51 holographic structure

Claims

1. A method for characterizing an optoelectronic measuring unit (1) for a textile test object which has an optical path for measuring light (17) used in measurements,

characterized in that

a substantially flat test pattern (2-5), which is neither an image nor an imitation of the test material is introduced into the optical path (19), and the test pattern (2-5) with the optoelectronic measuring unit (1) is measured.

2. The method of claim 1, wherein from the measurement at least one quality value

generated, the quality value is compared with a corresponding predetermined target value and a result of the comparison is output.

3. The method of claim 2, wherein at least one of the measurement

Testmustemiesswert is generated for at least one measurement parameter and the quality value is set equal to the test pattern measured value.

4. The method of claim 2, wherein at least one of the measurement

Testmustemiesswert for at least one measurement parameter generated, set a measurement target value for the Testmustemiesswert and in the calculation of the quality value, a mathematical relationship, preferably a difference and / or a quotient, between the Testmustemiesswert and the setpoint is formed.

5. The method according to claim 3 or 4, wherein the measurement parcel provider measured several times, an average over the plurality of measurements formed and the Testmustemiesswert is set equal to this mean.

6. The method according to any one of claims 3-5, wherein in each case at least one

Testmustemiesswert for several different Messparanieter is generated.

7. The method of claim 6, wherein a separate quality value is generated for each measurement parameter.

8. The method of claim 6 or 7, wherein a single total quality value is generated from the plurality of measurement parameters.

9. A method according to any of claims 2-5, wherein the quality target value corresponding to the quality value is previously assigned a tolerance range and the comparing is to determine whether the quality value is in the tolerance range or not, and wherein the result of the comparison is different depending after whether the quality value is in the tolerance range or not.

10. The method according to any one of the preceding claims, wherein the test pattern (2-5) is such that by means of the test pattern (2-5) at least one optical property of the optoelectronic measuring unit (1) can be characterized.

1 1. The method of claim 10, wherein the at least one optical property is selected from the following set: sharpness, resolution, contrast, brightness,

Color saturation, image position, geometry, scale of reproduction, image trimming.

12. The method of claim 10 or 1 1, wherein the test pattern (2, 4) in several

Sub-areas is divided so that the same optical property at different locations of the test pattern (2, 4) can be characterized and / or different optical properties are characterized.

13. Method according to one of the preceding claims, wherein the test pattern (5) includes a holographic structure (51).

14. Method according to one of the preceding claims, wherein the test pattern (2) is automatically introduced into the optical path, preferably by means of a telescopic arm (18), an extendable arm and / or a pivoting arm.

15. The method according to any one of the preceding claims, wherein the optoelectronic measuring unit (1) has a measuring field (14) for the textile material to be tested and the test pattern (2-5) instead of the textile material to be tested in the measuring field (14) is introduced (19).

16. The method of claim 15, wherein the test pattern (2-5) fills substantially the entire measuring field (14).

17. The method according to any one of the preceding claims, wherein the optoelectronic measuring unit (1) has a measuring field (14) for the textile Piiifgut and the test pattern (2-5) outside the measuring field (14) is introduced into the optical path.

A method according to any one of the preceding claims, wherein the test pattern (2-5) is moved during its measurement (28, 29).

19. The method of claim 1 8, wherein the movement comprises a displacement (28, 29)

and / or a rotation.

20. The method according to any one of the preceding claims, wherein due to the

Characterization of an adjustment of the optoelectronic measuring unit (1)

is made.

21. Use of a substantially planar test pattern (2-5), which is neither an image nor an imitation of a test material, for characterizing an optical measuring unit (1) for a textile test material.

22. combination of an optoelectronic measuring unit (1) for a textile test material,

which has an optical path for measuring light (17) used in measurements, and a substantially flat test pattern (2-5), which is neither an image nor an imitation of the test material and which can be introduced into the optical path.

23. An optoelectronic measuring unit (1) for a textile product which has an optical path for measuring light (17) used in measurements,

marked by

a substantially flat test pattern (2-5), which is neither an image nor an imitation of the test material, and

a loading device (18) for automatically introducing the test pattern (2-5) in the optical path.

24. The optoelectronic measuring unit (1) according to claim 23, wherein the introduction device (18) is designed as a telescopic Ann, as an extendable arm and / or as a Sehwenkann.