JPH0967760A - Woven cloth inspection and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid an erroneous inspection by excluding effects of the external disturbance on optical processing. SOLUTION: This method for inspecting a woven cloth W comprises arranging sensing ranges 201 and 211 of a photodetector elements 29 and 30 in the vicinity on the woven cloth W, converting a converted current signal inputted from photodetector elements 29 and 30 into a voltage signal and outputting the voltage signal to a differential computing circuit 36 with I/V converting circuits 34 and 35, outputting a differential signal of the voltage signal inputted from the I/V converting circuits 34 and 35 to a differential comparator circuit 37, judging whether or not a defect sensing signal is outputted to an output circuit 40 based on results of comparison between the inputted differential signal and the reference value preset by reference value setting circuits 38 and 39 with the comparator circuit 37, outputting the voltage signal to a comparator circuit 41 with the I/V converting circuit 35 and judging whether or not an inspection circumventing signal is outputted to the output circuit 40 based on the results of comparison between the inputted voltage signal with the reference value preset by reference value setting circuits 42 and 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a woven fabric inspection method and apparatus for detecting defects of a woven fabric woven by warps and wefts using a photoelectric sensor that outputs an electric signal according to the amount of received light. Is.

[0002]

2. Description of the Related Art A cloth inspection apparatus of this type is disclosed in Japanese Patent Application Laid-Open No. Sho 60-2.
No. 31,850. The reflected light of the light projected from the light source onto the woven fabric is received by the photosensitive cell.
An optical lens system is provided on the light path, and necessary optical processing such as condensing and collimating projection light or reflected light is performed by the optical lens system. The photosensitive cell outputs an electric signal corresponding to the amount of received light, and the electric signal is evaluated by the evaluation unit.

[0003]

The evaluation of the electric signal converted according to the amount of received light is generally performed by comparing the magnitude of the electric signal with a preset reference value. If the value of the electric signal is within the reference value, the normal evaluation is performed, and if the value of the electric signal exceeds the reference value, the abnormal evaluation is performed. However, since the loom vibrates violently, the optical processing performed by the optical lens system on the reflected light from the woven cloth varies. Such variations alter the electrical signal obtained from the same weave condition. Such a change in the electric signal makes it difficult to set the reference value,
False detection occurs.

It is an object of the present invention to provide a woven fabric inspection method and apparatus which can eliminate the influence of disturbance on optical processing and avoid false inspection.

[0005]

To this end, in the invention of claim 1, a plurality of points on the woven cloth are simultaneously scanned with light, and the light reflecting the weaving condition at one of the plurality of points is used as a reference electricity. Along with converting into a signal, the reference electric signal is compared with a reference reference value, and light reflecting the weaving state at least at the other of the plurality of points is converted into an electric signal for detection, and the electric detection is performed. Either one of the detection reference value and the detection electric signal to be compared with the signal is corrected based on the result of the comparison between the reference electric signal and the reference reference value.

According to the second aspect of the present invention, a plurality of points on the woven cloth are simultaneously scanned with light, the light reflecting the weaving condition at one of the plurality of points is converted into an electric signal for reference, and this reference is performed. The electric signal for reference and the reference reference value are compared, and the result of the comparison between the reference electric signal and the reference reference value by converting the light reflecting the weaving condition in at least another of the plurality of points into the electric signal for detection Based on the above, whether or not to adopt the electrical signal for inspection is determined.

In the invention of claim 3, the plurality of points are brought close to each other. In the invention of claim 4, the difference between the two electric signals obtained by converting the light, which reflects the weaving condition at the plurality of points, is calculated, and the difference obtained by this calculation is compared with the inspection reference value. .

According to a fifth aspect of the present invention, the first photoelectric sensor that receives light reflecting the woven state of the woven fabric and the second photoelectric sensor that has a detection area at a point different from the detection point of the photoelectric sensor And first comparing means for comparing a reference electric signal obtained from one of the first photoelectric sensor and the second photoelectric sensor with a reference reference value, and at least the first photoelectric sensor and the second photoelectric sensor. Second comparison means for comparing the electric signal for detection obtained from the other with the detection reference value, and correction means for correcting the comparison result in the second comparison means based on the comparison result of the first comparison means. And a woven fabric inspection device including

According to a sixth aspect of the present invention, the first photoelectric sensor that receives light reflecting the woven state of the woven fabric and the second photoelectric sensor that has a detection area at a point different from the detection point of the photoelectric sensor And a first comparing means for comparing a reference electric signal obtained from one of the first photoelectric sensor and the second photoelectric sensor with a reference reference value, and at least the other of the first photoelectric sensor and the second photoelectric sensor. Second comparison means for comparing the electric signal for detection obtained from the second detection means with the reference value for detection, and whether the comparison result in the second comparison means is judged based on the comparison result of the first comparison means. And a means for woven fabric inspection.

According to a seventh aspect of the present invention, a difference calculation means for calculating a difference between electric signals obtained from the first photoelectric sensor and the second photoelectric sensor, and a defect detection signal based on a calculation result of the difference calculation means. The first comparing means is provided with a defect determining means for determining whether or not to output.

According to the first and fifth aspects of the invention, the light reflecting the weaving condition at one of the plural points on the woven fabric is converted into the reference electric signal. Further, the light reflecting the weaving condition at least at the other points is converted into the electric signal for inspection. The reference electrical signal is compared with a reference reference value. Either one of the detection electric signal and the detection reference value is corrected according to the deviation between the reference electric signal and the reference reference value. The comparison between the electric signal for inspection and the reference value for inspection performed on the basis of such correction accurately reflects the weaving state.

According to the second and sixth aspects of the invention, the acceptance / rejection of the detection electrical signal is determined according to the degree of deviation between the reference electrical signal and the reference reference value. The comparison between the electrical signal for inspection and the inspection reference value, which is performed based on such acceptance or rejection, accurately reflects the weaving state.

According to the third aspect of the present invention, if the light receiving levels for a plurality of approaching points are the same and the light receiving level of the reference light is appropriate, the light receiving level of the light for inspection is also appropriate.

In the inventions of claims 4 to 7, a plurality of photoelectric sensors are arranged in the direction of one of the warp and the weft. The difference between the electric signal of at least one of these photoelectric sensors and the electric signal of the other photoelectric sensor is calculated, and the calculated difference is compared with, for example, a preset reference value. The calculation of the difference eliminates the change in the electric signal due to the influence of disturbance such as illumination light and cotton dust. If the calculated difference exceeds the reference value, the defect determining means outputs a defect detection signal. When the plurality of points are arranged in the weft yarn direction, the defect detection signal is output because the defect of the warp yarn is detected. When a plurality of points are arranged in the warp yarn direction, the defect detection signal is output because the defect of the weft yarn is detected.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment in which the present invention is embodied in a woven fabric inspection device on a loom will be described below with reference to FIGS.

As shown in FIG. 1, a rail 11 is arranged above the woven cloth W in the weft width direction of the woven cloth W. Rail 11
A sensor head 12 is suspended from and supported by a guide body 13. The guide body 13 can move along the rail 11. As shown in FIGS. 2 and 3, an endless belt 14 is coupled to the sensor head 12, and the endless belt 14 is
Is hung between the drive pulley 151 and the guide pulley 16 of the motor 15. The endless belt 14 is a motor 15
The sensor head 12 reciprocates along the rails 11 by the reciprocal driving of the sensor head 12. The sensor head 12 includes three reflecting mirrors 17, 18, 19 and a pair of rod-shaped convex lenses 2
It is equipped with 0 and 21.

As shown in FIG. 2, a light projector 22 is installed near the guide pulley 16. The projector 22 includes a container 23 and a projector element 24 attached to the bottom of the container 23.
And the slit plate 25 attached to the opening side of the container 22
And a rod-shaped convex lens 26 interposed between the light projecting element 24 and the slit plate 25. A slit 251 is formed in the slit plate 25. The light projecting element 24 is located on the focal point of the convex lens 26, and the light projected from the light projecting element 24 onto the convex lens 26 passes through the convex lens 26 and becomes parallel light. The chain line arrow in FIG. 1 represents the path of light. Convex lens 2
The optical axis of 6 passes through the center of the slit 251. Part of the light that has become parallel through the convex lens 26 is a slit 251.
Pass through. The slit plate 25 blocks the passage of light passing through the peripheral portion of the convex lens 26 in order to increase the parallelism of light.

The path of the parallel light passing through the slit 251 intersects with the reflecting mirror 17. The reflecting mirror 17 is inclined at 45 ° with respect to the surface of the woven cloth W, and the parallel light striking the reflecting mirror 17 is reflected toward the woven cloth W. The convex lenses 20 and 21 are symmetrically arranged on both left and right sides of the path of the reflected light from the reflecting mirror 17. The focal points of the convex lenses 20 and 21 are set on the woven cloth W, and the convex lenses 20 and 21 make the reflected light from the woven cloth W parallel light. The reflecting mirror 18 is arranged on the path of the parallel light emitted from the convex lens 20, and the reflecting mirror 19 is arranged on the convex lens 2
It is arranged on the path of the parallel light exiting from 1.

As shown in FIG. 3, a light receiver 27 is installed near the motor 15. The light receiver 27 is a container 28.
And the pair of light receiving elements 2 attached to the bottom of the container 28.
9, 30, a pair of rod-shaped condenser lenses 31 and 32 attached to the opening side of the container 28, and an extraction slit plate 33 interposed between the light receiving elements 29 and 30 and the condenser lenses 31 and 32. Consists of. The extraction slit plate 33 is formed with a pair of slits 331 and 332. Slit 331
Is opposed to the light receiving element 29, and the slit 332 is opposed to the light receiving element 30. The focus of the condenser lens 31 is at the center of the slit 331, and the focus of the condenser lens 32 is at the center of the slit 332. The optical axis of the convex lens 20 and the optical axis of the condenser lens 31 intersect on the reflecting surface of the reflecting mirror 18, and the optical axis of the convex lens 21 and the optical axis of the condenser lens 32 intersect.
Intersect on 9 reflective surfaces.

The parallel light reflected from the reflecting mirror 18 goes to the condenser lens 31, and the parallel light reflected from the reflecting mirror 19 goes to the condenser lens 32. The condenser lens 31 is the reflecting mirror 18.
The reflected light from is condensed on the slit 331, and the condenser lens 32 collects the reflected light from the reflecting mirror 19 on the slit 332. The light passing through the slits 331 and 332 is received by the light receiving elements 29 and 30. Slits 331,3
32 has a function of eliminating ambient light.

Reference numeral 201 shown in FIG. 4 indicates a detection range on the woven cloth W by the convex lens 20, and 211 indicates a detection range on the woven cloth W by the convex lens 21. The convex lens 20 has a detection range 2
A part of the scattered light reflected from 01 is focused into parallel light, and the convex lens 21 focuses a part of the scattered light reflected from the detection range 211 into parallel light. The warp threads T of the woven cloth W are passed between the reeds of a reed (not shown) in units of several lines, and the detection ranges 201 and 21
The width of the first weft yarn Y in the yarn direction is set to about the pitch of the reed wing. The width in the yarn direction of the warp yarns T of the detection ranges 201 and 211 is several times larger than the width of the weft yarn Y in the yarn direction.
The area surrounded by the arrow Q _R pointing to the right in FIG. 5 represents the sweep range of the detection ranges 201 and 211 on the woven fabric W due to the movement of the sensor head 12 in the right direction. Area surrounded by the arrow Q _L of left represents the sweep range of the detection area 201 and 211 on the fabric W by leftward movement of the sensor head 12. The woven fabric W moves in the direction of arrow R.

The light receiving elements 29 and 30 convert the received light into an electric current. This converted current signal becomes an electric signal according to the amount of received light. The light receiving element 29 outputs the converted current signal to the current-voltage conversion circuit 34 (hereinafter referred to as the I / V conversion circuit 34), and the light receiving element 30 outputs the converted current signal to the current-voltage conversion circuit 35 (hereinafter referred to as the I / V conversion circuit 34). It is output to the conversion circuit 35).
The I / V conversion circuits 34 and 35 convert the converted current signal into the voltage signal S.
It is converted to 1, S2 and output to the difference calculation circuit 36. The difference calculation circuit 36 calculates the difference between the values of the voltage signals S1 and S2 input from the I / V conversion circuits 34 and 35. In this calculation, the value of the voltage signal S2 is subtracted from the value of the voltage signal S1. The difference calculation circuit 36 outputs the difference signal ΔS obtained by the calculation to the comparison circuit 37.

The comparison circuit 37 receives the input difference signal ΔS and the reference value V preset by the reference value setting circuits 38 and 39.
1 and V2 are compared. The reference value V1 set by the reference value setting circuit 38 is positive, and the reference value V2 set by the reference value setting circuit 39 is negative. When the value of the difference signal ΔS is out of the reference range [V1, V2], the comparison circuit 37
Outputs the defect detection signal S _T to the output circuit 40. When the value of the difference signal ΔS is within the reference range [V1, V2], the comparison circuit 37 does not output the defect detection signal S _T to the output circuit 40.

The curve E in FIG. 6A is the I / V conversion circuit 34.
6B represents the voltage signal S1 output from the I / V conversion circuit 35, and the curve F in FIG. 6B represents the voltage signal S2 output from the I / V conversion circuit 35. The curve G in FIG. 6C represents the difference signal ΔS obtained by subtracting the value of the curve F from the value of the curve E. Square waves H1 and H2 in FIG. 6D represent the defect detection signal S _T output from the comparison circuit 37. The horizontal axis of each of FIGS. 6A to 6D represents time. The vertical axis in each of FIGS. 6A to 6C represents voltage.

The protruding portion E1 of the curve E represents an abnormality relating to the warp detected by the light receiving element 29. The protruding portion F1 of the curve F represents an abnormality relating to the warp detected by the light receiving element 30. The time difference between the protrusions E1 and F1 is the detection ranges 201 and 211 of the convex lenses 20 and 21 that move in the direction of the weft Y.
Are arranged in the weft Y direction. The protrusion G1 of the curve G is the difference between the protrusion E1 and the substantially flat portion of the curve F corresponding to the time region of the protrusion E1. Curve G
The protruding portion G2 is the difference between the protruding portion F1 and the substantially flat portion of the curve E corresponding to the time region of the protruding portion F1. The time width t1 of the square wave H1 corresponds to the time width of the protrusion G1 that exceeds the reference value V1 to the positive side, and the time width t2 of the square wave H2 corresponds to the time width of the protrusion G2 that exceeds the reference value V2 to the negative side. Corresponding to.

The warp thread T is passed between adjacent reeds in a fixed number of units. For example, between certain reeds, the number of warp threads is not sufficient, and the number of warp threads between adjacent reeds is specified. There may be situations where there are more than. If such a situation continues, so-called warp lines will occur on the woven fabric, resulting in a defective woven fabric. Detection ranges 201 and 211 of the convex lenses 20 and 21
The range of the weft Y in the yarn direction is set to about the pitch of the reed wing. Therefore, the amount of light received by the light receiving elements 29, 30 differs between the warp portion and the normal portion on the woven fabric W, and the curves E, F
The fluctuations of the voltage signals S1 and S2 are obtained as shown by the protrusions E1 and F1.

The output of the defect detection signal S _T represented by the square waves H1 and H2 is based on the result of comparison between the difference signal ΔS between the voltage signals S1 and S2 obtained from the light receiving elements 29 and 30 and the reference values V1 and V2. Will be judged. Disturbances such as the presence of illumination light other than the inspection device or the presence of cotton wool change the voltage signals S1 and S2. That is, the voltage signals S1 and S2 contain changes due to disturbance. Such a change in the voltage signals S1 and S2 does not correctly reflect the woven state of the woven cloth, and when it is determined whether or not there is a defect on the woven cloth based on the result of comparison between these voltage signals S1 and S2 and the reference value. False detection occurs. However, in the difference signal ΔS, which is the difference between the voltage signals S1 and S2, the change due to the disturbance that has entered each voltage signal is almost canceled. Therefore, the difference signal ΔS is
Accurately reflects the presence or absence of anomalies related to
The comparison between S and the reference values V1 and V2 enhances the accuracy of the detection, which is the detection of the presence or absence of an abnormality regarding the warp.

The I / V conversion circuit 35 also outputs the voltage signal S2 to the comparison circuit 41. The comparison circuit 41 compares the input voltage signal S2 with the reference values V3 and V4 preset by the reference value setting circuits 42 and 43. The reference value V3 is set by the reference value setting circuit 42, and the reference value V4 is set by the reference value setting circuit 43. A reference range [V in which the value of the voltage signal S2 serving as a reference electric signal serves as a reference reference value
3, V4], the comparison circuit 41 outputs the detection invalidation signal N to the output circuit 40. When the value of the voltage signal S2 is within the reference range [V3, V4], the comparison circuit 4
1 does not output the detection / invalidation signal N to the output circuit 40.

When the defect detection signal S _T is output when the detection / invalidation signal N is not output, the output circuit 40 outputs a weaving stop signal, an abnormality display signal and the like. However, when the test invalidation signal N is output, the output circuit 40 does not output the weaving stop signal, the abnormality display signal, etc., despite the output of the defect detection signal S _T.

The light receiving element 29 is a photoelectric sensor that receives light reflecting the woven state of the woven cloth W, and the light receiving element 30 is a photoelectric sensor that has a detection area at a point close to the detection point of the photoelectric sensor. The comparison circuit 37 uses an electric signal obtained from the light receiving element 29 and a reference range [V1,
V2] as a second comparing means. Comparison circuit 4
Reference numeral 1 is a first comparing means for comparing an electric signal obtained from the light receiving element 30 with a reference range [V3, V4] which is a reference reference value. The output circuit 40 serves as an acceptance / rejection determining means for determining acceptance / rejection of the comparison result of the second comparing means based on the comparison result of the first comparing means.

Since the loom is vibrating violently, the focal points of the convex lenses 20 and 21 are not always located exactly on the woven cloth W. When the focal points of the convex lenses 20 and 21 deviate from the woven cloth W, the light receiving levels of the light receiving elements 29 and 30 deviate from the desired light receiving levels. Reference range [V3, V4]
Is set corresponding to an allowable light receiving level, and the voltage signal S2 obtained from the light receiving element 30 is set in the reference range [V
3, V4], the light receiving level is within a proper range. Since the focal points of the convex lenses 20 and 21 on the woven cloth W are close to each other, if the light receiving level of the light receiving element 30 is proper, the light receiving level of the other light receiving element 29 is also proper. Although the focal points of the convex lenses 20 and 21 on the woven cloth W are close to each other, the scattered light from the focal point of one convex lens does not affect the light receiving level of the light receiving element corresponding to the other convex lens. If the light receiving level of the light receiving element 30 is proper, the detection invalidation signal N is not output, and if the light receiving level of the light receiving element 30 is not proper, the detection invalidation signal N is output.

In this embodiment, two close points (shown as detection ranges 201 and 211 in FIG. 4) on the woven cloth W are simultaneously scanned with light to detect the detection ranges 201 and 211.
The reflected light from is picked up as light for inspection and light for reference. The reflected light from the detection range 211 is used as the detection light and the reference light, and the reflected light from the detection range 201 is used as the detection light. The light that reflects the weaving condition at one of these two points is the reference electrical signal (ie, voltage signal S2).
Is converted to This reference electric signal is compared with a reference range [V3, V4] serving as a reference reference value, and whether the difference ΔS between the electric signals obtained by converting the light reflecting the weave state at the two points is adopted or not is determined by the reference electric signal and the reference reference. It is determined based on the result of comparison with the value. The comparison between the electric signal for inspection (the difference signal ΔS in this embodiment) and the reference value for inspection performed on the basis of such adoption or rejection accurately reflects the weaving state.

Next, a second embodiment shown in FIG. 7 will be described. The same components as those in the first embodiment are denoted by the same reference numerals. In this embodiment, the voltage signal S1 output from the I / V conversion circuit 34 is sent to the comparison circuit 44 as well as the difference calculation circuit 36. The comparison circuit 44 receives the input voltage signal S
1 and the reference values V3 and V4 preset by the reference value setting circuits 42 and 43 are compared. When the value of the voltage signal S1 is out of the reference range [V3, V4], the comparison circuit 44
Outputs the detection / invalidation signal N2 to the output circuit 45. When the value of the voltage signal S1 is within the reference range [V3, V4], the comparison circuit 44 does not output the detection invalidation signal N2 to the output circuit 45. The value of the voltage signal S2 is in the reference range [V3, V
4], the comparison circuit 41 outputs the detection invalidation signal N1 to the output circuit 45. When the value of the voltage signal S2 is within the reference range [V3, V4], the comparison circuit 41 does not output the detection / invalidation signal N1 to the output circuit 45.

The output circuit 45 outputs a weaving stop signal, an abnormality display signal and the like in response to the output of the defect detection signal S _T only when the detection invalidation signals N1 and N2 are simultaneously input. In this way, even if one of the detection ranges 201 and 211 extracts the light reflecting the defect on the woven fabric as the light for reference, it is not determined that the light receiving level is inappropriate. Therefore, the defect on the woven cloth is the detection range 201.
Even if the defect cannot be detected for some reason when entering, the defect on the woven fabric is detected in the detection range 211.
The possibility of successful detection of this defect remains on entering, and the certainty of early detection of defect detection on the woven fabric is higher than in the case of the first embodiment.

Next, a third embodiment shown in FIG. 8 will be described. The same components as those in the first embodiment are denoted by the same reference numerals. In this embodiment, the correction circuit 46 corrects the difference signal ΔS output from the difference calculation circuit 36 based on the reference value V5 preset by the reference value setting circuit 47 and the voltage signal S2. The reference value V5 is set corresponding to an appropriate light receiving level in the light receiving element 30. Reference value V5
Is shown in FIG. 6 (a). The correction circuit 46 corrects the difference signal ΔS as ΔS · V5 / S2, for example, and compares it with the comparison circuit 3
Output to 7. When the corrected difference signal ΔS · V5 / S2 is out of the reference range [V1, V2], the comparison circuit 37
Outputs the defect detection signal S _T to the output circuit 40.

If the received light level is higher than the appropriate level, the difference signal ΔS, which should originally be within the reference range [V1, V2], may deviate from the reference range [V1, V2]. On the contrary, when the light receiving level is too lower than the appropriate level, the difference signal ΔS, which should originally be out of the reference range [V1, V2], may fall within the reference range [V1, V2]. The comparison between the detection electric signal and the detection reference value, which is performed by the correction circuit 46 after the above-described correction, accurately reflects the weaving state and prevents false detection.

Although the difference signal ΔS is corrected in this embodiment, an embodiment in which the reference range [V1, V2] is corrected is also possible. Next, a fourth embodiment of FIG. 9 will be described. The same components as those in the first embodiment are denoted by the same reference numerals. In this embodiment, a pair of reflecting mirrors 48, 49 and a pair of convex lenses 50, 51 are mounted on the sensor head 12. Convex lens 50,
The focus of 51 is set on the woven fabric W. Reflector 48,
49 is on a line connecting the light projector 22 and the light receiver 27. The reflecting mirrors 48 and 49 are tilted in opposite directions with respect to the optical axis of the convex lens 26 and the optical axes of the condenser lenses 31 and 32 at a certain angle. The slit plate 25 has a pair of slits 252, 2
53 are formed. The parallel light that has passed through the slits 252 and 253 is reflected by the reflecting mirror 48 toward the woven fabric W. Part of the light reflected from the woven cloth W is a convex lens 50, 5
It is collimated by 1. These parallel rays are reflected by the mirror 4.
It is reflected toward the condenser lenses 31 and 32 by 9.

Although the focal points of the convex lenses 50 and 51 on the woven cloth W are apart to some extent, there is no great difference in the light receiving level with respect to the detection range on each focal point. Therefore, also in this embodiment, the same effect as in the first embodiment can be obtained.

Further, in the present invention, an embodiment in which the detection ranges are arranged in the yarn direction of the warp yarn is possible. . When the detection range is arranged in the warp yarn direction, the defect detection signal is output because the defect of the weft yarn is detected.

As shown in FIG. 10, a fifth embodiment in which the difference calculation circuit in each of the above embodiments is not used is also possible. In this embodiment, the comparison circuit 52 directly compares the reference value preset by the reference value setting circuit 53 with the voltage signal S1, and based on the comparison result, the defect detection signal S _T
Is output.

The effects of the embodiment will be described below. (1) In the embodiment in which the difference between the electric signals obtained by converting the light that reflects the weaving condition at a plurality of points is calculated and the difference obtained by this calculation is compared with the inspection reference value, The influence of disturbances such as illumination light other than the inspection device can be eliminated, which contributes to avoiding false inspection. (2) In the embodiment in which a plurality of points indicated by the detection range are brought close to each other, the light receiving level for each point is the same, and it is possible to accurately determine whether the light receiving level of the inspection light is appropriate. (3) In the embodiment in which light picked up from a plurality of points is used as the reference light, early detection of defects on the woven fabric is guaranteed.

[0042]

As described above in detail, based on the result of the comparison between the reference electric signal for converting the light reflecting the weaving condition at one of the plural points on the woven cloth and the reference reference value, In the invention that corrects either one of the detection reference value and the detection electric signal that is the comparison target of the detection electric signal obtained by converting the light that reflects the weaving state at least at another point, the disturbance to the optical processing is The influence of can be eliminated and false inspection can be avoided.

Based on the result of the comparison of the reference electric signal for converting the light, which reflects the weaving condition at one of the plural points on the woven cloth, and the reference reference value, the weaving condition at at least the other points of the plural points is reflected. In the invention for determining whether to adopt the inspection electric signal obtained by converting the light, the influence of disturbance on the optical processing can be eliminated to avoid erroneous detection.

[Brief description of drawings]

FIG. 1 is a partially omitted front view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a combination diagram of a detection range on a woven fabric and a control circuit.

FIG. 5 is a plan view showing a scanning area of a detection range.

6A to 6D are graphs illustrating signal processing in a control circuit.

FIG. 7 is a combination diagram of the detection range on the woven fabric and the control circuit according to the second embodiment.

FIG. 8 is a combination diagram of a detection range on a woven fabric and a control circuit according to the third embodiment.

FIG. 9 is a partially omitted front view showing a fourth embodiment.

FIG. 10 is a partially omitted front view showing a fifth embodiment.

[Explanation of symbols]

2011, 211 ... A detection range that is one of a plurality of points,
29, 30 ... Light receiving element serving as photoelectric sensor, 36 ... Difference arithmetic circuit, 37 ... Comparison circuit serving as second comparing means, 38, 3
9 ... Reference value setting circuit for setting inspection reference value, 4
0, 45 ... Output circuit serving as acceptance / rejection judging means, 41 ... Comparison circuit serving as first comparing means, 42, 43 ... Reference value setting circuit for setting reference reference value, 46 ... Correction circuit serving as correcting means, W ... Woven cloth.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01N 21/89 G01N 21/89 C

Claims (7)

[Claims] 1. A woven fabric inspection method for detecting a defect of a woven fabric by using a photoelectric sensor that outputs an electric signal according to an amount of received light that reflects a woven state of the woven fabric, and a plurality of points on the woven fabric. Are simultaneously scanned with light to convert the light reflecting the weaving condition at one of the plurality of points into a reference electric signal, and compare the reference electric signal with a reference reference value to determine the plurality of points. The light reflecting the weaving state in at least the other is converted into an electric signal for detection, and reference is made to either one of the reference electric value for detection and the electric signal for detection to be compared with the electric signal for detection. Woven fabric inspection method that corrects based on the result of comparison between the electrical signal for use and the reference value. 2. A woven fabric inspection method for detecting a defect of a woven fabric by using a photoelectric sensor that outputs an electric signal according to an amount of received light reflecting a woven state of the woven fabric, and at a plurality of points on the woven fabric. Are simultaneously scanned with light to convert the light reflecting the weaving condition at one of the plurality of points into a reference electric signal, and compare the reference electric signal with a reference reference value to determine the plurality of points. Of light that reflects the weaving state in at least another of the weaving conditions is converted into an electric signal for detection, and whether or not the electric signal for detection is adopted is determined based on the result of the comparison between the reference electric signal and the reference reference value. Cloth inspection method. 3. The woven fabric inspection method according to claim 1, wherein the plurality of points are brought close to each other. 4. The method according to claim 1, wherein two differences between light-converted electric signals that reflect the weaving condition of the plurality of points are calculated, and the difference obtained by this calculation is compared with the inspection reference value. Item 5. The woven fabric inspection method according to any one of Item 3. 5. A woven fabric inspection device for detecting a defect of a woven fabric by using a photoelectric sensor which outputs an electric signal according to an amount of received light which reflects a woven state of the woven fabric. From a first photoelectric sensor that receives reflected light, a second photoelectric sensor that has a detection region at a point different from the detection point of the photoelectric sensor, and one of the first photoelectric sensor and the second photoelectric sensor A first comparing means for comparing the obtained reference electric signal with the reference reference value; and a detection electric signal and a detection reference value obtained from at least the other of the first photoelectric sensor and the second photoelectric sensor. A woven fabric inspection device comprising: a second comparing means for comparing; and a correcting means for correcting the comparison result of the second comparing means based on the comparison result of the first comparing means. 6. A woven fabric inspection device for detecting a defect of a woven fabric by using a photoelectric sensor which outputs an electric signal according to an amount of received light which reflects the woven state of the woven fabric. From a first photoelectric sensor that receives reflected light, a second photoelectric sensor that has a detection region at a point different from the detection point of the photoelectric sensor, and one of the first photoelectric sensor and the second photoelectric sensor A first comparing means for comparing the obtained reference electric signal with the reference reference value; and a detection electric signal and a detection reference value obtained from at least the other of the first photoelectric sensor and the second photoelectric sensor. A woven fabric inspection device comprising: a second comparing means for making a comparison; and an acceptance / rejection determining means for determining acceptance / rejection of a comparison result by the first comparing means based on the comparison result of the second comparing means. 7. A difference calculation means for calculating a difference between electric signals obtained from the first photoelectric sensor and the second photoelectric sensor, and whether or not to output a defect detection signal based on a calculation result of the difference calculation means. 7. A first comparing means comprising a defect determining means for determining whether or not it is any one of claims 5 and 6.
The woven fabric inspection device according to the item.