JPH06116846A - Fabric inspection apparatus - Google Patents

Abstract

PURPOSE:To improve reliability of judging result by removing disturbing noise causing error judgement. CONSTITUTION:An oscillator 22 which outputs a control signal SGref of frequency fref is connected through a projecting and driving circuit 21 to a projector 20 and the projector 20 is subjected to pulse lightening in a frequency fref A space filter 28 connected to a differential control circuit 31 receives image of woven fabric relatively moving while flashing in frequency fref and the differential control circuit 31 outputs a signal having an inspection signal K of frequency f (<< fref as amplitude. The differential control circuit 31 and the oscillator 22 are together connected to a multiplier 32 and the multiplier 32 is connected to a low path filter 33, a full-wave rectifier circuit, a peak detection circuit 35, a low path filter 36, a comparator amplifier circuit 37 and a judging circuit 38 in order. Consequently, even if a disturbing noise is mixed in an output signal SG1, an output signal SG3 of the low path filter 33 becomes inspection signal K from which the disturbing noise is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for optically detecting a defect of a woven cloth.

[0002]

BACKGROUND OF THE INVENTION It is desirable to detect and repair defects in woven fabrics early during weaving. As a method of solving this problem, the applicant of the present application has proposed, in Japanese Patent Laid-Open No. 3-249243, an inspecting device which can be installed in a loom to detect defects of a woven fabric in a weaving process.

As shown in FIG. 8, the inspection device 41 has a cloth fell W.
1 and the expansion bar 42, the sensor box 44 is guided by the guide rail 46 on the drive screw 45 along with the forward and reverse rotation of the motor 43, and reciprocates in the width direction of the woven fabric W at a predetermined speed v. It is supposed to do. On the lower surface side of the woven cloth W, a reflection plate 4 extending to face the drive screw 45 is provided.
7 are arranged.

As shown in FIG. 9, a light projector 48 is installed in the sensor box 44, and the light from the light projector 48 is reflected by a half mirror 49 to be applied vertically to the woven cloth W. The irradiation light is reflected by the reflection plate 47 on the lower surface side of the woven fabric W,
An image of the woven fabric W is formed on the spatial filter 51 through the half mirror 49 and the convex lens 50.

The spatial filter 51 is composed of two comb-shaped filter portions 53a and 53b, which are provided with a large number of light receiving elements 52a and 52b arranged at a constant pitch P, and are arranged to face each other.
The image of the warp threads T of the woven cloth W is arranged so as to be parallel to the longitudinal direction of the light receiving elements 52a and 52b. As a result, the image of the warp yarn T moves substantially orthogonal to the longitudinal direction of the light receiving elements 52a and 52b while maintaining the state parallel to the longitudinal direction of the light receiving elements 52a and 52b, and the warp yarns 52a and 52b move. The image of T is received as light and dark. The received light is converted into an electric signal and output as a detection signal from the comb filter units 53a and 53b to the differential operation circuit 54.

The differential operation circuit 54 calculates the output difference based on each detection signal and outputs it as an output signal SG1 (detection signal). The frequency f of the detection signal is given by the following equation. f = (m / P) · v where m is the imaging magnification (= D / H), and P is the light receiving element 52.
The pitch of a and 52b, and v is the scanning speed of the sensor box 44. The output signal SG1 is subjected to full-wave rectification by the full-wave rectification circuit 55 for determination processing (SG7), held at a peak value by the peak value detection circuit 56 (SG8), and further subjected to smoothing processing by the low-pass filter 57. The output signal SG9 is output to the comparison circuit 58.

The comparison circuit 58 determines whether or not the output signal SG9 is larger than a preset reference value Et, and if it is larger, the duration B is counted by a clock pulse, and the duration B is the reference time. If longer than ts, the determination circuit 59 determines that there is an abnormality. That is, when the gain of the detection signal of the frequency f (output signal SG1) exceeds the preset value EN for a certain period of time, the determination circuit 59 determines that the woven fabric W has an abnormality. This determination signal is output to a control device of the loom and an informing device that informs the operator of the abnormality. When an abnormality is detected in the woven cloth W, the operation of the loom is stopped, the lamp is lit, a warning sound is generated, and the like. To inform the occurrence of abnormalities such as warp breakage.

[0008]

However, in the output signal SG1 (detection signal) from the differential operation circuit 54, the disturbance light noise generated by the sensor box 44 detecting the disturbance light from the lighting or the like in the factory. The electrical noise mixed during the transmission of the detection signal and the detection signal was superimposed. As a result, these disturbance noises may be determined by the determination circuit 59 as abnormalities of the woven cloth W, although the woven cloth W is not actually abnormal.

For example, as shown in FIG. 10, disturbance noise having a frequency lower than the output frequency f is superposed on the detection signal to obtain a value EN.
When it exceeds (SG1), the output signal SG9 of the low-pass filter 57 exceeds the reference value Et, and the comparison circuit 58 continues the duration B.
Are counted. If the duration B is longer than the reference time ts, the determination circuit 59 will determine that there is an abnormality.

Further, as shown in FIG. 11, when disturbance noise having a frequency higher than the output frequency f is continuously superimposed on the detection signal and exceeds the value EN (SG1), these disturbance noises are detected by the peak value detection circuit. The peak value is held at 56 (SG8). Therefore, the output signal SG9 of the low-pass filter 57 exceeds the reference value Et, and the comparison circuit 58 continues the time B.
Are counted. If the duration B is longer than the reference time ts, the determination circuit 59 will determine that there is an abnormality.

Then, the inspection device 41 stops the operation of the loom or issues an alarm notifying the operator of the abnormality of the woven cloth based on the erroneous determination due to the disturbance noise, even though the woven cloth W is not abnormal. Was. As a result, the operating rate of the loom is reduced, and the worker is forced to perform a wasteful work of searching for a defect of the woven cloth that does not actually exist.

The present invention has been made in order to solve the above problems, and its purpose is to eliminate the disturbance noise that causes erroneous determination, thereby improving the reliability of the determination result. To provide an anti-device.

[0013]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a light-emitting body for irradiating light on an inspection area of a woven fabric,
A light receiving body that moves relative to the woven cloth and receives light from the detection area of the woven cloth as an image of the woven cloth and converts the light into an electric signal; and the light receiving body and the woven cloth output from the light receiving body. In an inspecting device having a determining means for determining pass / fail of a woven fabric based on an inspecting signal having a frequency based on a relative movement with an image, an oscillator for outputting a reference signal having a frequency higher than the frequency of the inspecting signal. And a light emission drive circuit for pulse-lighting the light emitter at the frequency of the reference signal based on the reference signal, and an output signal having an amplitude of a detection signal from the light receiver and the reference signal for multiplication and multiplication. A multiplier for outputting as a signal and a filter circuit for transmitting at least the same frequency component as the frequency of the detection signal from the multiplied signal are provided.

[0014]

Therefore, according to the present invention, the oscillator outputs the reference signal having a frequency higher than the frequency of the detection signal. Based on this reference signal, the light emission drive circuit causes the light emitting body to pulse-light according to the frequency of the reference signal. The light from the light emitter is applied to the inspection area of the woven cloth, and the light from the inspection area is imaged on the photoreceptor as a blinking woven cloth image. Therefore, the output signal from the photoreceptor has an amplitude of a detection signal having the detection information from the true woven fabric image having a frequency based on the relative movement between the photoreceptor and the woven fabric image, and the woven fabric image It becomes a sine wave that oscillates at the frequency of the reference signal that blinks.

When the output signal from the photoreceptor is multiplied by the reference signal from the oscillator by the multiplier, a signal in which the frequency component of the detection signal and the frequency component larger than the frequency of the detection signal are superposed. Becomes The filter circuit transmits at least the frequency component of the detection signal of the multiplied signal, and the other frequency components are removed together with the disturbance noise. Therefore, since the detection signal including almost no disturbance noise is obtained, it is possible to significantly reduce the erroneous determination of the disturbance noise as a defect of the woven fabric by the determination means, and to realize a highly reliable detection.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inspection device according to an embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 7, the weft yarn inserted into the opening of the warp yarn T formed by the opening movement of the heddle frame 1 constituting the shedding device is struck by the reed 2 onto the cloth cloth W1 of the woven fabric W, Woven cloth W is formed. The woven cloth W is taken up at a predetermined speed by the take-up action of the press roller 4 and the surface roller 5 which constitute the woven cloth take-up section via the expansion bar 3 at a predetermined speed, and is taken up by the take-up roller 6. A detection device 7 is arranged between the cloth fell W1 and the expansion bar 3, and the detection device 7 includes a housing box 8 and a reflection plate 9.

As shown in FIGS. 5 and 6, the accommodating box 8 is disposed below the woven cloth passing position such that the longitudinal direction thereof is the width direction of the woven cloth W, and the woven cloth W is placed on the upper portion thereof. A window 8a having a length equal to or larger than the width is formed. A reflection plate 9 that covers the window 8a is detachably attached to the upper side of the storage box 8 with bolts 9a, and the woven cloth W moves while being sandwiched between the storage box 8 and the reflection plate 9. There is. The lower surface of the reflecting plate 9 facing the woven cloth W is mirror-finished.

A running rail 1 is provided at the bottom of the storage box 8.
0 is laid, and two sensor heads 11 are installed on the traveling rail 10 so as to be movable via a base 13 in a state of being separated by a connecting member 12 at a constant interval. Each sensor head 11 is formed with a detection window 11a facing the back surface of the woven cloth W.

A motor 14 composed of an AC servomotor is arranged at one end of the housing box 8, and a pulley 15 is attached to the rotary shaft of the motor 14. A pulley 16 is provided at a position where the pulley 15 and the traveling rail 10 are opposed to each other,
A scanning belt 17 is wound around both pulleys 15 and 16, and the scanning belt 17 is fixed to one side portion of both bases 13.

As a result, the two sensor heads 11 reciprocate in the width direction of the woven fabric W at a constant speed v along the traveling rail 10 in accordance with the forward and reverse rotations of the motor 14 under the drive control of a controller (not shown). It has become. Then, each sensor head 11 scans each half of the inspection area that divides the woven cloth W into two in the width direction. In addition, a wiring cable 18 made of an FPC (flexible wiring board) capable of following the reciprocating movement is connected to each sensor head 11, and supplies power to each sensor head 11 and signals between each sensor head 11 and the controller. Used for sending and receiving. The inspection region is set to a region where the scanning speed v of the sensor head 11 is constant.

Next, the structure of the sensor head 11 and the determination processing of the detection signal from the sensor head 11 will be described with reference to FIGS.
Follow the instructions below. Two sensor heads 11 are provided, but both have the same configuration, so the sensor head 11 on the left side of FIG. 5 will be described.

As shown in FIG. 1, the sensor head 11
A light emitting diode (LED) is provided inside the base 19.
The optical device 20 is fixed downward. This floodlight 20
It is connected to an oscillator 22 which will be described later via a light emission drive circuit 21.
Frequency f output from the oscillator 22_refControl signal
SG_refBased on the frequency f
_refIt is designed to be pulsed at (Fig. 2). Floodlight
A half mirror 23 is arranged below the container 20 in the vertical direction.
It is placed in a state of being inclined by 45 degrees, and it is placed in front of it (see
The mirror 24 is inclined 45 degrees to the left).
It Above the mirror 24, a convex lens forming the detection window 11a is formed.
Lens 25 is arranged, and the lens 25 is placed at the focal position of the convex lens 25.
By placing the optical device 20, the convex lens 25 and the woven cloth W
The light irradiating to is parallel light.

A convex lens 26 is arranged behind the half mirror 23, and a light receiving substrate 27 is arranged further behind. At the position where the light receiving substrate 27 is arranged, the light from the inspection area, that is, the reflected light from the woven cloth W is convex lens 25,
It is a position where an image is formed on the light-receiving surface 27a as a surface pattern of the woven fabric W via 26. The light from the light projector 20 is configured not to directly enter the light receiving substrate 27.

As shown in FIG. 2, on the light receiving surface 27a of the light receiving substrate 27, a spatial filter 28 having a differential structure as a light receiving body is formed.
Is provided. The spatial filter 28 is composed of a pair of comb-shaped filter portions 30a and 30b in which a large number of light receiving elements 29a and 29b that output a current according to the amount of received light are formed in parallel with each other at a constant pitch P. Light receiving element 29a,
The pitch P of 29b is set corresponding to the pitch of the image of the warp T of the woven fabric W, and the longitudinal direction of the light receiving elements 29a and 29b is the direction orthogonal to the moving direction of the image of the woven fabric W, that is, the warp T. Is arranged so as to be parallel to the image (the warp direction in the figure). Therefore, the spatial filter 28 has a good detection sensitivity in the warp direction, and particularly detects defects in the warp direction selectively.

The image of the woven fabric W moves at a relative speed mv with respect to the light receiving elements 29a and 29b because the scanning speed of the sensor head 11 is v, where m is the imaging magnification of the convex lenses 25 and 26. At that time, if the woven cloth W has a non-uniform portion such as a warp break, the image of the non-uniform portion is distributed to a large number of light receiving elements 29a and 29b arranged at a pitch P of a period T (= P / (mv. )) Sequentially receives light. That is,
The frequency f based on the relative movement between the light receiving elements 29a and 29b and the image of the woven cloth W is expressed by the following equation.

F = 1 / T = (m / P) v (1) On the other hand, the oscillator 22 has a constant amplitude and a frequency f _ref (<< f) sufficiently higher than the frequency f as shown in the following equation. The control signal SG _ref is output.

SG_ref= 2sin2πf_reft (2) This control signal SG_refIs output to the light emission drive circuit 21,
The light projecting drive circuit 21 receives the control signal SG_refControl signal based on
No. SG_refSame phase and same frequency f_refAC voltage V
(= V_maxsin2πf_reft) is applied to the projector 20
It Therefore, the projector 20 including the LED is controlled by the control signal SG.
_refWhen f is positive (+), light is emitted and frequency f _refIn pal
It is supposed to light up. That is, the light receiving surface 27a
The image of the woven fabric W formed at the frequency f_refWhile flashing at
It moves on the light receiving surface 27a at a relative speed mv. In addition, the actual
In the embodiment, the frequency f is about 0.5 to 1 kHz, and the frequency f
_refIs about 10 to 100 kHz.

Each comb filter portion 30 of the spatial filter 28
a and 30b are connected to a differential operation circuit 31 via a current-voltage conversion circuit (not shown) that converts a current into a voltage, and the differential operation circuit 31 receives the detection signals from the comb filter units 30a and 30b. The output difference is calculated based on this, and output as the output signal SG1.

The differential operation circuit 31 and the oscillator 22
Are both connected to the multiplier 32, and the output signal SG1 and the control signal SG _ref are both output to the multiplier 32. At this time, the output signal SG1 and the control signal SG _ref have the same phase. Further, the multiplier 32 sequentially operates the low pass filter 3
3, the full-wave rectification circuit 34, the peak value detection circuit 35, the low-pass filter 36, the comparison circuit 37, and the determination circuit 38.

The multiplier 32 outputs the output signal SG1 and the control signal S
G _ref is subjected to multiplication calculation processing and output to the low-pass filter 33 as an output signal SG2. The cut-off frequency f _C of the low-pass filter 33 is set to f ≦ f _C <f _ref , and the low-pass filter 33 transmits the frequency component below the cut-off frequency f _{C in the} output signal SG2 and exceeds the cut-off frequency f _C. Remove frequency components. The output signal SG3 of the low-pass filter 33 is output to the full-wave rectifier circuit 34, and the full-wave rectifier circuit 34 full-wave rectifies the output signal SG3 and outputs the output signal SG4. The peak value detection circuit 35 outputs a signal formed by holding the peak value of the output signal SG4 at a preset time constant as the output signal SG5, and the low pass filter 36 smoothes the output signal SG5 and outputs it. It is output as a signal SG6. And
The comparison circuit 37 outputs the output signal SG6 of the low-pass filter 36.
To determine whether it is larger than a preset reference value Et (EN / 2). If it is larger, the duration of the large state is counted by the clock pulse CLK, and the count value y
Is output to the determination circuit 38 as the duration B.

The judgment circuit 38 compares the continuation time B with a preset reference time ts, and when the continuation time B exceeds the reference time ts, judges that the woven cloth W has an abnormality such as warp breakage. The reference time ts is obtained in advance by test operation. Then, the determination signal of the determination circuit 38 is output to the control device of the loom and a notification device that informs the operator of the abnormality, and when an abnormality of the warp T is detected, the operation of the loom is stopped or the operator is turned on by a lamp and a buzzer. The woven cloth W is informed of the abnormality.

Next, the operation of the inspection device configured as described above will be described. As shown in FIG. 5, the woven cloth W woven at the cloth fell W1 moves while being wound by the winding roller 6 and sandwiched between the housing box 8 of the inspection device 7 and the reflecting plate 9. . When the motor 14 rotates forward and backward by drive control of a controller (not shown), the scanning belt 17 rotates forward and backward via the pulleys 15 and 16. Along with the forward and reverse rotations, the two sensor heads 11 reciprocate at a constant speed V along the traveling rail 10 in the width direction of the woven fabric W at a constant interval. As a result, each sensor head 11 scans each half of the detection area that divides the woven cloth W into two in the width direction.

At this time, when power is supplied to each sensor head 11 from a power source (not shown) via the wiring cable 18,
As shown in FIG. 5, the light projector 20 formed of an LED is driven and controlled by the light projecting drive circuit 21 inside the sensor head 11 to pulse-light at the frequency f _ref . The light of the projector 20 is reflected by the half mirror 23 and the mirror 24, and then the convex lens 2
The light becomes parallel light at 5 and is radiated vertically from the detection window 11a onto the back surface of the woven fabric W.

The light applied to the woven cloth W is reflected directly on the back surface of the woven cloth W or on the lower surface of the reflection plate 9 arranged on the upper side of the woven cloth W, and enters the detection window 11a again as reflected light. The reflected light that has passed through the convex lens 25 is reflected in the horizontal direction by the mirror 24, passes through the half mirror 23, is focused by the convex lens 26, and is imaged as a surface pattern of the woven cloth W on the light receiving surface 27a of the light receiving substrate 27. .

At this time, as shown in FIG. 2, the image of the woven fabric W blinks at the frequency f _ref and the light receiving element 2 at the relative speed mv.
The light receiving surface 2 is formed in a direction substantially orthogonal to the longitudinal direction of 9a and 29b.
Move on 7a. At that time, the image of the warp T (the warp direction shown in the figure) is always parallel to the longitudinal direction of the light receiving elements 29a and 29b, so that the spatial filter 28 has good detection sensitivity in the warp direction, particularly in the warp direction. Selectively detect defects.

The light receiving elements 29a and 29b receive the image of the woven fabric W moving at the relative speed mv while blinking at the frequency f _ref , and output it as a current signal having a current value corresponding to the received light amount. Each of the comb filter units 30a and 30b converts this current signal into a voltage signal via a current-voltage conversion circuit (not shown) and then outputs it as a detection signal to the differential operation circuit 31. The differential operation circuit 31 includes comb filter units 30a and 30b.
The output difference is calculated based on the respective detection signals from and output as the output signal SG1.

As shown in FIG. 3, the output signal SG1 (signal G) is the amplitude of the detection signal K of the frequency f (= mv / P) which gives information (test information) of the surface pattern of the woven fabric W. Mochi,
It is represented by a sine wave of frequency f _ref (>> f) based on the blinking of the image of the woven cloth W. The detection signal K which is the amplitude of the signal G is expressed by the following equation.

K = K (t) = A (t) sin2πft (3) Here, A (t) is the amplitude of the detection signal K and corresponds to the surface state of the woven cloth W (whether there is a defect or not). It is a function of the time t which changes. Therefore, the output signal SG1 (= G) is expressed by the following equation.

SG1 = G = K (t) sin2πf _ref t = A (t) sin2πft · sin2πf _ref t (4) However, the applied voltage V (= V _max sin2π) is applied to the projector 20.
Since light is emitted only when f _ref t) is plus (+),
At time t when the applied voltage V becomes V <0 (SG _ref <0), the output of the signal G becomes 0. That is, the signal G is a signal of only a half wave on the same sign side as the detection signal K (t) in the equation (4) which is an amplitude modulated wave.

The output signal SG1 is output to the multiplier 32 together with the control signal SG _{ref of the} equation (2) output from the oscillator 22. The multiplier 32 multiplies the output signal SG1 and the control signal SG _ref , which are in phase with each other, to calculate the product of them, and outputs the product as the output signal SG2. The output signal SG2 is as follows from the expressions (2) and (4).

[0042] _{SG2 = SG1 · SG ref = G} · SG ref = 2A (t) sin2πft · sin 2 2πf ref t = A (t) sin2πft · {1-cos2π (2f ref) t} ... (5) where control Time t when the signal SG _ref becomes SG _ref <0
When, the output of the output signal SG2 becomes 0 (FIG. 3).
The output signal SG2 is output to the low pass filter 33.

Since the cutoff frequency f _C of the low-pass filter 33 is set to f ≦ f _C <f _ref , the first term of the equation (5) in the output signal SG2 is transmitted and the second term is removed. It As a result, the output signal SG3 of the low pass filter 33 is given by the following equation.

SG3 = A (t) sin2πft = K (t) (6) That is, the output signal SG3 is the signal G (output signal SG1).
Becomes equal to the inspection signal K which is the amplitude of (FIG. 3).

On the other hand, the output signal SG1 of the differential operation circuit 31
Disturbance noise N (= N (t) sin2πf of frequency f _{N
When N} t) is mixed, the output signal SG1 becomes a signal in which the disturbance noise N is superimposed on the signal G, and therefore the output signal SG2 of the multiplier 32 is as follows.

[0046] _{SG2 = SG1 · SG ref = (} G + N) · SG ref = G · SG ref + N · SG ref ... (7) where the first term of (7) is represented by equation (5), second The terms are as follows.

N · SG_ref= 2N (t) sin2πf_Nt · sin2πf_reft = N (t) {cos2π (f_N-F_ref) T-cos2π (f_N+ F_ref) T} (8) where the cutoff frequency f of the low-pass filter 33 is_C
Is f ≦ f_C<F_refSince it is set to
The second term is the frequency f_NRegardless of the low pass filter 33
Will be removed. The first term in equation (8) is the frequency f_NIs f_C<
| F_N-F_refIs satisfied if | is satisfied. Sanawa
The disturbance noise N has a frequency f_NIs f_N<F _ref-F_C，
f_ref+ F_C<F_NIf it is in the range of
f_ref-F _C≤ f_N≤ f_ref+ F_CIf the range is
As long as it is transparent. Therefore, the low pass filter 33
Toff frequency f_CF_CAs small as possible within the range of ≧ f
Disturbance noise N can be removed more effectively by setting
Be done.

For example, f _ref = 50 kHz, f _C = 0.
When set to 7 kHz, the frequency f _N is 49.3 kHz ≦
Only the disturbance noise N in a very limited range of f _N ≦ 50.7 kHz is transmitted, but the frequency f outside this range is f.
Disturbance noise N of the _N is removed. In particular, ambient light noise of about 120 Hz or less from factory lighting or the like is reliably removed.

Therefore, even if the disturbance noise N is mixed in the output signal SG1, the frequency f _{N of the} disturbance noise _N is f _N <f
_{When ref} −f _C and f _ref + f _C <f _N , the output signal SG3 of the low-pass filter 33 is expressed by equation (6). That is, the output signal SG3 is not affected by the disturbance noise N and becomes equal to the detection signal K which is the amplitude of the signal G. The output signal SG3 is output to the full-wave rectifier circuit 34.

As shown in FIGS. 2 and 4, the output signal SG3 is full-wave rectified by the full-wave rectification circuit 34 and output as the output signal SG4, and the output signal SG4 is held at the peak value by the peak value detection circuit 35. It is output as the output signal SG5. Further, the output signal SG5 is subjected to smoothing processing by the low pass filter 36 and is output as the output signal SG6 by the comparison circuit 37.
Is output to.

The comparison circuit 37 determines whether or not the level of the output signal SG6 is larger than a preset reference value Et, and if it is larger, the duration B of the large state is counted by the clock pulse CLK, and The count value y is output as the duration B to the determination circuit 38. If the duration B is longer than the reference time ts, the determination circuit 38 determines that there is an abnormality, and if the duration B is shorter than the reference time ts or is not counted, the determination circuit 38 determines that there is no abnormality.

Therefore, even if the disturbance noise N is mixed in the output signal SG1, the detection signal K (output signal SG3) from which the disturbance noise component is removed is obtained from the low-pass filter 33, so that the judgment circuit 38 disturbs the disturbance noise. False determination of N as a defect of the woven fabric W is significantly reduced. For example,
Even if the disturbance noise N having a frequency f _N (f _N <f <f _ref −f _C ) lower than the frequency f of the detection signal K is mixed in the output signal SG1, the output signal SG3 of the low-pass filter 33 is not affected by the disturbance noise N. Contains no ingredients. Further, the output signal SG1 has higher and lower frequencies f _N (f <f _N <than the frequency f of the detection signal K.
Even if high-frequency disturbance noise N of f _ref −f _C and f _ref + f _C <f _N ) is continuously mixed, the output signal SG3 of the low-pass filter 33 does not include a disturbance noise component. As a result, the determination circuit 38 determines that there is no abnormality. In addition,
The disturbance noise _N whose frequency f _N is in the range of f _ref −f _C ≦ f _N ≦ f _ref + f _C is transmitted to the low pass filter 33, but is extremely small among the disturbance noise N superimposed on the signal P. , The determination circuit 38 has almost no adverse effect on the determination.

Then, the determination signal of the determination circuit 38 is output to the control device of the loom and the notification device for notifying the operator of the abnormality, and when an abnormality is detected in the woven cloth W, the operation of the loom is stopped or the lamp is lit. A warning sound is generated to notify the operator of the occurrence of abnormalities such as warp breakage. Since this determination signal is a highly reliable signal that is not affected by disturbance noise, there is no concern that the operation of the loom will be unnecessarily stopped or the operator will be given a false alarm.

Therefore, according to the inspection device 7 of this embodiment,
A frequency f higher than the frequency f of the detection signal K
By turning on the pulse with _ref , the differential operation circuit 31
Of the output signal SG1 of the frequency f whose amplitude is the detection signal K
An amplitude modulated wave of _ref (>> f) could be obtained. Therefore, even if the disturbance noise N is mixed in the output signal SG1, the detection signal K from which the disturbance noise component is removed can be taken out by being processed by the multiplier 32 and the low-pass filter 33. The determination circuit 3 is determined by the detection signal K.
Since the quality of the woven fabric W is determined in 8, it is possible to largely prevent the erroneous determination that the disturbance noise N is a defect of the woven fabric W. As a result, the control device stops the weaving machine based on the erroneous determination in the determination circuit 38, or the operator searches for a defect of the woven fabric W which does not actually exist due to an erroneous alarm such as lighting of a lamp or generation of a warning sound. It is possible to prevent unnecessary work. Furthermore, since these can be prevented, the operating rate of the loom can be improved.

Further, since the storage box 8 is arranged under the woven cloth W and the window 8a is covered with the reflection plate, the light from the factory lighting or the like enters the storage box 8 as disturbance light. This can be avoided, and ambient light noise can be prevented. Furthermore, since the inside of the housing box 8 is shielded from the outside to prevent the intrusion of dust, fly and the like, it is possible to prevent the determination circuit 38 from making an erroneous determination due to the detection of dust, fly and the like. Further, the woven cloth W that moves while slidingly contacting the window 8a of the storage box 8 has a cleaning effect on the window 8a, and the upper surface of the window 8a is always kept in a clean state. It is possible to further prevent the erroneous determination of.

The present invention is not limited to the above embodiments, but may be constructed as follows, for example, within the scope of the invention. (1) In the above embodiment, the reflection plate 9 is arranged on the upper side of the window 8a of the storage box 8, but the reflection plate 9 is not arranged and the light reflected on the back surface of the woven cloth W is detected to detect the woven cloth. The quality of W may be determined. In this case, even if the ambient light of about 120 Hz or less from the illumination in the factory is detected, the ambient light noise is surely removed. Further, it is not necessary to remove the reflection plate 9 for repairing the defect of the woven cloth W, and the workability can be improved.

(2) In the above embodiment, the low pass filter 3
Although 3 is connected between the multiplier 32 and the full-wave rectification circuit 34, the connection position of the low-pass filter 33 may be appropriately set as long as the disturbance noise can be effectively removed. For example, it may be provided between the full-wave rectification circuit 34 and the peak value detection circuit 35. Further, in this case, the cutoff frequency f _C of the low pass filter 33 may be set to the cut off frequency f _AC (<f) of the low pass filter 36 to eliminate the peak value detection circuit 35 and the low pass filter 36.

[0058] (3) cut-off frequency f _C of the frequency f _ref and the low-pass filter 33 of the control signal SG _ref can be appropriately set according to the frequency f of the frequency f _N and Kenhan signal K of the disturbance noise mixed .

(4) In the above embodiment, the light receiving body is the spatial filter 28, but the light receiving body is, for example, a phototransistor.
A photoelectric conversion element other than the spatial filter 28 such as an image sensor may be used.

(5) Two sensor heads 11 are provided in the above embodiment, but the number of sensor heads 11 may be set appropriately. (6) In the above embodiment, the abnormality in the warp direction of the woven cloth W is detected, but the abnormality in the weft direction or the abnormality in both the warp and weft directions may be detected.

(7) In the above embodiment, the inspection device 7 is provided between the cloth fell W1 and the expansion bar 3, but it may be provided between the press roller 4 and the take-up roller 6. Further, the storage box 8 may be on the upper side of the woven cloth W.

(8) In the above embodiment, the inspection device 7 was installed in the loom to detect the defects of the woven fabric W in the weaving process. However, the inspection device 7 is used independently in the inspection process after the weaving process. You may.

[0063]

As described in detail above, according to the present invention, by removing the disturbance noise that causes an erroneous determination, the reliability of the determination result can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a sensor head according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an order in which an output signal from a spatial filter is subjected to determination processing according to an embodiment.

FIG. 3 is a waveform diagram showing the order in which the output signal from the differential operation circuit is shaped into a detection signal in one embodiment.

FIG. 4 is a waveform diagram showing an order in which an inspection signal is shaped for a determination process in one embodiment.

FIG. 5 is a partially exploded perspective view of the inspection device according to the embodiment.

FIG. 6 is a sectional view taken along line XX of FIG. 5 in the inspection device according to the embodiment.

FIG. 7 is a perspective view showing an inspection device installed in a loom according to an embodiment.

FIG. 8 is a perspective view of a conventional inspection device.

FIG. 9 is a principle diagram of the inspection in the inspection device of the related art.

FIG. 10 is a waveform diagram of a signal including disturbance noise that malfunctions the conventional detection device.

FIG. 11 is a waveform diagram of a signal including disturbance noise different from that in FIG. 10, which causes a malfunction of the conventional detection device.

[Explanation of symbols]

20 ... Projector as light emitter, 21 ... Projection drive circuit as light emission drive circuit, 22 ... Oscillator, 28 ... Spatial filter as photoreceiver, 32 ... Multiplier, 33 ... Low-pass filter as filter circuit, 37 ... Judgment Comparing circuit forming means, 38 ... Judging circuit forming judging means, W ... Woven cloth, K ... Detecting signal, SG _ref ... Control signal as reference signal, SG3 ... Output signal as multiplying signal.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location G02B 27/46 9120-2K (72) Inventor Shigeto Ozaki 2-chome, Toyota-cho, Kariya city, Aichi prefecture Stock company Toyota Automatic Loom Works

Claims (1)

[Claims] 1. A light-emitting body that irradiates light on a detection area of a woven fabric, and light that moves relative to the detection area of the woven cloth and receives light from the detection area of the woven cloth as an image of the woven cloth and converts it into an electrical signal. Detecting device including a light receiving body to be converted, and a judging means for judging whether the woven cloth is good or bad by an inspection signal having a frequency based on the relative movement of the light receiving body and the image of the woven cloth output from the light receiving body. In the device, an oscillator that outputs a reference signal having a frequency higher than the frequency of the inspection signal, a light emission drive circuit that makes the light emitter pulse-light at the frequency of the reference signal based on the reference signal, and from the light receiver A multiplier for multiplying the output signal having the detection signal of the amplitude as the amplitude and the reference signal to output as a multiplication signal, and a filter circuit for transmitting at least the same frequency component as the frequency of the detection signal from the multiplication signal. Inspection device.