WO2000028120A2

WO2000028120A2 - Acquisition system for examining woven fabric

Info

Publication number: WO2000028120A2
Application number: PCT/FR1999/002699
Authority: WO
Inventors: Georges Cornuejols; Jean-Philippe Roux; Patrice Pennel; Philippe Guermonprez
Original assignee: Visioreg S.A.
Priority date: 1998-11-05
Filing date: 1999-11-04
Publication date: 2000-05-18
Also published as: WO2000028120A3

Abstract

The invention concerns a device for examining woven fabric comprising at least one camera (416A to 416X) sensing an image of part of an unwinding woven fabric, and emitting a signal representing the sensed image. It further comprises processing means (604, 605, 606) which process: one first time each image-representing signal and assesses the presence of faults in the part represented by said signals; for each fault whereof the presence has been assessed as probable, at least a second signal representing the woven fabric to confirm the presence of said fault.

Description

ACQUISITION SYSTEM FOR ^INSPECTION OF TISSUE

I. First perspective

The present invention relates to a tracking device and an inspection device incorporating such a tracking device

The point of locating devices on a fabric presently known use a tracking based on a position in length measured with an encoder wheel When the fabric tension varies, tracking ^s' is too imprecise to find a small object, such as a defined of the fabric Indeed, the variation in tension can modify the length of the fabric by a factor which can exceed ten percent

Other devices use marks, for example reflective, positioned regularly for example every meter, and the location of a point of the fabric is done by counting the number of marks passed and adding a measurement of the length made to a given voltage These devices have the following three drawbacks

- on the one hand, the cost of brands is quite high,

- on the other hand, these marks can interfere with the process of exploiting the fabric, for example by coming off in a dye bath,

- the above imprecision defect is not completely eliminated, and - it is difficult to automatically detect the marks because it is necessary to follow the edges of the fabric.

The present invention intends to remedy these drawbacks

To this end, the present invention relates, according to a first aspect, to a device for locating a point on a fabric, characterized in that it comprises a means for detecting picks of the fabric and a means for determining the pick corresponding to the point a so, whatever the tension of said fabric, the point is marked to within one pick

According to particular characteristics, the locating device as succinctly set out above comprises a means of determining said pick with respect to a mark secured to the fabric

Thus, even if one end of the fabric has imperfections or a fold which could disturb the detection of the first picks. from the mark considered, the pick of the point to be located is correctly determined and invariable

According to particular characteristics, the locating device as succinctly described above comprises a moven for determining said dmte with respect to marks integral with the fabric regularly spaced on said fabric

So, yes. between two marks, a fold πsque to disturb the detection of at least one pick, the following mark allows to reset the count of the dmtes

According to particular characteristics, the pick determination means includes a mark setting means

According to a second aspect, the present invention relates to a fault detection device characterized in that it comprises a tracking device as succinctly set out above. According to particular characteristics, said fault detection device comprises a first assembly comprising a fabric unwinder, a means of detecting faults, a locating means as succinctly explained above and a fabric winder, and

- A second assembly comprising a fabric unwinder, a means for presenting defects, a locating means as succinctly set out above and a fabric rewinder According to a third aspect the present invention relates to a method of locating stitch on a fabric , characterized in that ^it comprises a dmtes detecting operation of the fabric and a corresponding weft of the determining operation at the point of tissue spot

In a fourth aspect the present invention provides a method of tissue inspection, caracteπse in ^that d has a fault detection operation of tissue, a step of determining a pick of the fabric corresponding to said event and an operation of memonsatton information representative of said pick

The advantages of the second, third and fourth aspects of the invention being identical to those of the first aspect of the invention, they are not repeated here.

The invention also relates to an information medium retaining instructions of a program adapted to be implemented by a processor to carry out the process as succinctly set out above. This fault detection device and this information medium having the same advantages as the tracking device, these advantages are not recalled here π. Second perspective

The present invention relates to a method and a device for inspecting fabric, a weaving machine and a cutting machine using them.

The fabric inspection devices known to date use a linear camera which continuously captures an image of the fabric, and an image processing means which processes the images coming from the linear camera to detect weaving defects. These devices are very expensive and cannot be made profitable The present invention intends to remedy these drawbacks To this end, the present invention aims, according to a fifth aspect, to a device for inspecting fabric during weaving on a weaving machine, characterized in that ^'' it includes

at least one camera adapted to capture an image of the last thread inserted into the fabric, and to provide a signal representative of said image, and

- an image processing means adapted to process signals representative ^of images captured by each camera, and detecting in said image, ^the ^image of at least one fault weaving

Thanks to these provisions, as soon as the thread has been inserted into the fabric, its image is captured by the camera and processed by the processing means. A defect is therefore immediately detected, which allows

- to stop the loom in that ^a fault has been detected.

- reduce the amount of fabric that is woven after ^the appearance of the defect and - if the machine weave allows unweave tissue and repair the defect

According to particular features, the inspection device such as briefly exposed above comprises at least two cameras each having an array sensor, and said processing means is adapted to process, alternatively, the representative ^image signals from the different cameras Thanks to these provisions, low-cost cameras are implemented and it is particularly easy.

According to other particular characteristics, the device as succinctly explained above comprises a multiplexing and digitizing means adapted to successively supply a digital signal representative of the image captured by the sensor of each camera.

Thanks to these provisions, numerous cameras can be used and the dimension of the smallest area of the tissue that can be treated is very small, which allows the detection of very small defects.

According to other particular characteristics, said processing means comprise a microprocessor.

Thanks to these provisions, the image processing is, at least partially, carried out by said processor, which allows complex image processing.

According to other particular characteristics, the device as briefly described above comprises a machine stop control means adapted to cause a weaving stop, and the processing means is adapted to control the operation of the control means d 'machine stop.

Thanks to these provisions, the defects which definitively reduce the value of the fabric can be stopped before affecting a large length of fabric.

According to other particular characteristics, the processing means is adapted to determine, for each fault detected, whether it is capable of being repaired and, if so, to control the operation of the machine stop control means.

With these arrangements, when ^a fault is likely to be repaired, such as a wire breakage fault or oil stain, the machine shutdown is caused and an operator, or the weaving machine itself even, can act and reduce the importance of the defect, even repair it.

According to other particular characteristics, the device as succinctly described above comprises a untwisting means and the processing means is adapted to determine, for each defect capable of being repaired, whether a untwisting is necessary and, in the yes, to remove, at least partially, the tissue.

Thanks to these provisions, automatically or with the action of an operator, the fault is repaired. According to other particular characteristics, the device as briefly described above comprises an input synchronizing signal on which a signal representative ^of at least one phase of the operating cycle of the weaving machine, is present.

Thanks to these provisions, the processed images can be synchronized with the operating cycle of the machine, to prevent the fabric from moving, or from cyclic vibrations of the cameras disturbing the quality of the processed images.

According to ^other particular characteristics, the processing means is adapted to detect an absence of the last thread that should have been inserted into the tissue and at least one other fault of the last wire inserted into the woven Thanks to these provisions, as soon as the insert yarn in the fabric has a defective anomaly or fault ^insertion, this fault is detected, the machine can optionally be stopped and possibly the defect can be repaired.

In a sixth aspect the present invention provides a method ^for inspection of fabric being woven on a weaving machine, characterized in ^that it implements at least a suitable camera to capture an image of the last wire inserted into the tissue and providing a signal representative of said image, and in ^that it comprises

- an image processing operation during which treated signals representative of images captured by each camera, and if it is detected in said image, is ^the image of at least a weaving fault.

The present invention also provides a weaving machine, characterized in that ^it comprises an ^inspection device as briefly described above

The present invention also provides a memory that retains instructions ^of a suitable program to be executed by a processor, and allowing implementation of the method of the present mvenϋoa The advantages of this method of this memory and this machine weave being the same as those of the fifth aspect of the invention, ds are not repeated here. read. Third perspective

The present invention relates to a method and a device ^for inspecting fabric during weaving. The fabric inspection devices known to date use a linear camera which continuously captures an image of the fabric, and an image processing means which processes the images coming from the linear camera to detect weaving defects. These devices are very expensive and cannot be made profitable. The present invention intends to remedy these drawbacks.

To this end, the present invention provides, according to a seventh aspect, an inspection device of fabric being woven on a weaving machine, characterized in that ^it comprises

at least one camera adapted to capture an image of the tissue, during a viewing period, and to emit a signal representative of the captured image,

a synchronization means adapted to emit a signal representative of the position of the comb of the weaving machine, and a processing means adapted, for each camera, to process a signal representative of the image leaving said camera and corresponding to a viewing period during which the comb does not strike the fabric.

Thanks to these provisions, during the viewing period. the fabric is essentially stationary and ^the processed image has only little or no motion blur The processing means then makes it possible to detect more defects than in the case where the péπode of view pπse does ^not exclude the péπode typing comb on the fabric.

According to particular characteristics, each camera has a clock and is adapted to capture images only cyclically, with a constant period

Thanks to these provisions, the implementation of the present invention is easy and low cost. According to ^other specific caracteπstiques the ^inspection device as succinctly outlines above

• comprises an image memory and an image digitization moven adapted to supply, under the control of the processing means, for each image captured by a camera, a digital signal representative of said image, to said memory, and

- when the processing means has completed an image processing, it is adapted to wait for a signal representative of the striking of the comb, before starting a new image processing

Thanks to these provisions, the implementation of the present invention is particularly simple since, once the image processing has been carried out, the processing means commands the storage of new images, in order to process them, in turn ^. there is then no problem of synchronization of the viewing means and the processing means, since they have to act successively

According to other particular characteristics, said cameras are adapted to be controlled by an external synchromsation signal to trigger a view point and the emission, by each camera, of the signal representative of the image captured during said view point thanks to these provisions, it ^is not necessary ^to wait for the cameras operating cvcle is completed to perform new images of storing the speed of the device is improved

According to other particular characteristics, the inspection device as succinctly explained above comprises a camera control means adapted to receive the signal representative of the position of the comb of the weaving machine, and to control the view pπse cameras, transmitting to them said synchromsation signal. the instant of transmission of said synchromsation signal depending on the signal representative of the position of the comb

Thanks to these provisions, the synchromsation between the position of the comb and the instant of sight pπses is improved According to other particular characteristics

- the processing means is adapted to provide the command moven with information representative of the approach or occurrence of the end of the processing,

- Said control means is adapted to the fact that the instant of transmission of said synchromsation signal depends on the instant of the end of the processing carried out by the processing means. Thanks to these provisions, the pπse of views can be carried out during the end of the processing of the images previously stored and / or processed or just at the end of this processing The operating speed of the device aimed by the present invention is therefore improved

According to other particular characteristics, the inspection device as succinctly described above comprises at least one camera adapted to capture an image of the last thread inserted into the fabric, and to provide a signal representative of said image.

Thanks to these arrangements, that ^a fault occurs on the fabric, that ^it is, or not, binds to the last inserted wire, it can be detected When ^a machine shutdown looms is needed to repair the tissue, amount of fabric of lesser quality is reduced, and in case a repair is possible, repair is easier and faster since ^it is little tissue that presents the defect repair o

In particular for weaving machines which can not détisser ^that one or two son, immediate detection ^of a defect on the last thread inserted allows détisser this wire and repair the defect.

According to an eighth aspect, the present invention relates to a process ^for inspecting fabric during weaving, on a weaving machine, characterized in that: - it uses at least one camera adapted to capture an image of the fabric, during a shooting period, and to transmit a signal representative of the captured image,

it includes a synchronization operation during which information representative of the position of the comb of the weaving machine is transmitted, and

a processing operation during which, for each camera, a signal representative of the image leaving said camera is processed and corresponding to a shooting period during which the comb does not strike the fabric.

The present invention also relates to a weaving machine, characterized in that it comprises an inspection device as succinctly set out above.

The present invention also relates to a memory which stores instructions of a program adapted to be executed by a processor, and allowing the implementation of the method of the present invention.

The advantages of this process, this memory and this weaving machine being the same as those of the seventh aspect of the invention, they are not repeated here. IV. Fourth perspective

The present invention relates to a method and a device for inspecting objects, for example, of fabric, and, in particular, of inspecting fabrics during weaving or during unrolling on a cutting table.

The fabric inspection devices known to date use a linear camera which continuously captures an image of the fabric, and an image processing means which processes the images coming from the linear camera to detect weaving defects. These devices are very expensive and cannot be made profitable. The present invention intends to remedy these drawbacks.

To this end, the present invention aims, according to a ninth aspect, an inspection device, characterized in that it comprises:

- at least two cameras, each adapted to capture an image of part of the tissue, and to emit a signal representative of the captured image, - processing means adapted to process more frequently a signal representative of the image leaving one of the cameras ^that an outgoing signal representative image of another camera.

Thanks to these provisions, an area of an object to be inspected, for example, a fabric or a manufactured object, in which it is considered that several shots are necessary to correctly detect a defect either because in this area the faults are more difficult to detect, either because in this area the defects are more likely to occur, or still, because in this region, the object has a more rapid movement is less well illuminated only ⁱⁿ the light ^of a another camera, is the object of image processing more frequent than other zones of said object. According to particular characteristics,

• the device as briefly described above comprises a probable position estimation using ^at least one defect on said fabric, and - the processing means is adapted to process more frequently a signal representative of each camera image output which corresponds to a said fault position probable that ^a signal from another camera.

Thanks to these provisions, the positions where it is likely to find a defect are inspected frequently - than the positions where it is unlikely to find a defect. The treatment of such default ^the stopping of the loom, the unweaving, cleaning can then be more quickly after the fault occurred.

Moreover, in case a thorough inspection of the tissue ^is not possible, for example because the treatments applied image by means of processing the signals from the cameras is very complex, the provisions of the present invention allow a exhaustive inspection of positions where it is deemed likely to find a defect.

According to particular characteristics, the estimation means is adapted to estimate that the edges of the fabric are probable positions of defects.

Thanks to these provisions, draw-in faults and breakage of threads, which are frequent on a given weaving machine, are detected quickly.

According to other particular characteristics, the estimation means is adapted to estimate that the position where the processing means has detected the last fault is a probable fault position.

Thanks to these provisions, when a part of the weaving machine or a part of the wheel which supplies the warp threads, is defective and causes the appearance of repeated fabric defects, the particular provisions of the present invention make it possible to detect quickly the appearance of such tissue defects

According to other particular characteristics, the processing means is adapted, when it has detected a defect in an image taken by a camera, to process a new image taken by said camera and the estimation means is adapted to estimate that the position where the processing means has detected a defect in two images processed successively and taken by the same camera is a probable position of defect. Thanks to these provisions, when the appearance of a defect is confirmed on two images processed successively and coming from the same camera, the position of this defect is inspected more frequently.

According to other particular characteristics, the processing means is adapted, when ^it has detected a fault in an image taken by a camera, to process a new image taken by said camera and the estimating means is adapted to estimate the position where the processing means has detected a fault on the first of two images processed successively and taken by the same camera is a likely fault position.

With these arrangements, when the appearance ^of a defect is not confirmed on two images processed successively from the same camera, the default position is inspected more frequently because it is considered suspicious.

Of course, a position where a defect was confirmed is still considered more suspect that ^a position where a defect ^has not been confirmed.

According to other particular characteristics, the processing means is adapted, when it has detected at least one type of defect, to cause a stopping of the weaving machine and the estimation means is adapts to estimate that the position where the processing moven has detected a fault which has caused the machine to stop is a likely fault position

Thanks to these provisions, a repair carried out on the detected fault, repair which may have caused new faults, gives a more frequent inspection. According to other particular characteristics, the inspection device aimed at by the invention, as succinctly described herein above comprises a camera sequencing means suitable for orgamming an order of cameras whose images are successively processed by the processing means said processing means being adapted to process the images coming from the cameras in the order of the cameras in the orgamsee sequence by the sequencing moven Thanks to these provisions, for a given camera, the frequency of processing of images originating from said camera is given by the number of times the camera appears in the orgamsee sequence by the sequencing means.

According to a tenth aspect, the present invention relates to a method of inspecting fabric during weaving, on a weaving machine, characterized in that - it implements at least one camera adapted to capture an image of the fabric, during a view period, and send a signal representative of the captured image,

it comprises an operation for estimating the probable position of at least one defect on said fabric, and

- a processing operation adapted to process more frequently a signal representative of the image leaving each camera qm corresponds to a so-called probable fault position

The invention also relates to a weaving machine, characterized in that it comprises an inspection device as succinctly set out above.

The present invention also relates to a memory q keeps instructions of a program adapted to be executed by a processor, and allowing the implementation of the method of the present invention The advantages of this method, this memory and this weaving machine being the same as those of the ninth aspect of the invention, they are not recalled here V. Fifth perspective

The present invention relates to a method and a device for inspecting fabric during weaving. The fabric inspection devices known to date use a linear camera which continuously captures an image of the fabric, and a moven for processing ^. image q processes images from the linear camera to detect weaving defects These devices are very expensive and cannot be made profitable

The present invention intends to remedy these drawbacks

To this end, the present invention provides, according to an eleventh aspect, a fabric inspection device, caracteπse in ^that it comprises

- at least two cameras adapted to receive, each, an image ^of a portion of the tissue, and transmitting a signal representative of the captured image,

a selection means adapts, for each camera, to selecting a part of the image, and

- a processing moven adapted to process said image parts and to detect at least one weaving defect Thanks to these provisions, each camera can be selected part ^of image that matches:

Or - the part of the better picture quality (due to imperfections in the lens or lighting, for example) - or to the part of ^the image which covers an area of tissue that n ^has not yet inspected,

- or to a part of ^the image that is most prone to have defects.

By thus selecting parts of images, the present invention avoids the processing means from processing all of the captured images.

According to particular characteristics, the optical fields of the cameras extend, jointly over the entire width of the fabric to be inspected.

According to other particular characteristics, the selection means is adapted to select parts of images which, jointly extend over the entire width of the fabric to be inspected.

Thanks to each of these provisions, the entire fabric can be inspected, during the movement of this fabric or of the cameras, facing the fabric. According to other particular characteristics, the inspection device as succinctly described above comprises:

an image processing means adapted to process signals representative of images captured by each camera, and to detect in said image, the image of at least one weaving defect.

Thanks to these arrangements, as soon as the thread has been inserted into the fabric, its image is captured by the camera and processed by the processing means. A fault is therefore immediately detected, which allows:

- stop the weaving machine as soon as a fault has been detected,

- to reduce the quantity of fabric which is woven after the appearance of the defect and, - if the weaving machine allows it, to loosen the fabric and to repair the defect.

According to other particular characteristics, the inspection device as briefly described above is associated with a weaving machine and comprises:

- at least one camera adapted to capture an image of the tissue, during a shooting period, and to emit a signal representative of the captured image, - synchronization means adapted to emit a signal representative of the position of the comb the weaving machine, and

a processing means adapted, for each camera, to process a signal representative of the image leaving said camera and corresponding to a shooting period during which the comb does not strike the fabric. Thanks to these provisions, during the shooting period, the fabric is practically immobile and the processed image comprises little or no motion blur. The processing means then can detect more defects than in the case where the shooting time does ^not exclude the period of reed beat on the fabric. According to other particular characteristics, the processing means is adapted to process more frequently a signal representative image out of one of the cameras ^that a representative image output signal of a autrccaméra.

Thanks to these provisions - a zone of a - object to be inspected, for example., A fabric or a manufactured object, in which it is considered that several shots are necessary to correctly detect a defect either because in this zone the defects are harder to detect, either because in this area the defects are more likely ^to occur, or still, because in this region, the object has a more rapid movement is less well illuminated than to look another camera, is the object of ^image processing more frequently than other areas of said object. According to other caracléπstiques part rail, the inspection device, as. Succinctly described above comprises a means of estimating the likely position of at least one defect on said fabric, and the processing means is adapted to treat more frequently a representative of each camera image output signal which corresponds to a said fault position probable that ^a signal from another camera.

Thanks to these provisions, the positions where it is likely to find a defect are inspected more frequently than the positions where it is unlikely to find a defect. The treatment of the defect, for example stopping the weaving machine, untwisting, cleaning can then be done more quickly after the appearance of the defect.

In addition, in the case where an exhaustive inspection of the tissue is not possible, for example because the image processing applied by the processing means to the signals from the cameras is very complex, the provisions of the present invention allow a exhaustive inspection of positions where it is deemed likely to find a defect.

According to a twelfth aspect, the present invention relates to a method of inspecting tissue, characterized in that:

d uses at least two cameras adapted to each capture an image of part of the tissue and to transmit a signal representative of the captured image,

it includes a selection operation during which, for each camera, an image part is selected, and

- A processing operation during which said image parts are processed and at least one weaving defect is detected there. The present invention also relates to:

- a weaving machine, characterized in that ^it comprises an inspection device as briefly described above,

- a fabric cutting machine, characterized in that ^it comprises an inspection device as briefly described above. The present invention also relates to a memory which stores instructions of a program adapted to be executed by a processor, and allowing the implementation of the method of the present invention.

The advantages of this process, this memory and this weaving machine being the same as those of the eleventh aspect of the invention, they are not repeated here. VI. Sixth perspective The present invention relates to a method and a device for inspecting fabric during weaving.

The fabric inspection devices by camera known to date carry out the treatment of faults by processing fabric images. The detection of faults then depends on detection zones which, when they are too large, cause false detections, c that is, good quality fabric is considered defective and when they are too narrow, do not allow the detection of all defects

The present invention intends to remedy these drawbacks.

To this end, the present invention provides, according to a thirteenth aspect, a fabric inspection device, caracteπsé in ^that it comprises - at least one camera adapted to capture an image of a portion of the tissue being scrolled, and transmitting a signal representative of ^the captured image, and

a processing means adapted to process for the first time each image representative signal, and to evaluate the presence of defects in the part of the tissue represented by said signal and, for each defect whose presence is thus evaluated as probable, to be processed at least one second signal representative of the fabric to confirm the presence of said defect

Thanks to these provisions, the detection cπtères used for the first treatment can be quite wide and, during each second treatment, false detections are eliminated on a new image representative signal.

According to particular characteristics, the processing means is adapted so that the parts of the tissue represented by the first image representative signal and by each second image representative signal have a non-empty intersection in which the defect considered likely is found. .

Thanks to these provisions, during each processing, it is a signal representative of this intersection q is processed.

According to other particular characteristics, the processing means is adapted so that each second processing is carried out with the same cπteres as the first processing in such a way as a signal representative of image qm, during the first processing has a presence probable of defect, also presents, during each second treatment, a confirmation of said defect

Thanks to these provisions, the implementation of the present invention is simple and inexpensive. According to other particular characteristics, the processing means is adapted so that

the first processing assigns a type, from a plurality of fault types, to each fault the presence of which is evaluated as probable, and

- each second treatment is carried out with defect confirmation cπteres q depend on the type of defect attributed to the defect during the first treatment Thanks to these provisions, the elimination of detection faults is made more effective since the confirmation cπteres are specifically adapts to the type of defect whose presence is sought to be confirmed For example, when the type of defect is a hole, if a defect surface area is used, the limit value for deciding on the presence of defect represents a very small surface because that no hole, even of small size is tolerated in a fabric It is therefore impossible for a hole to be detected during a first treatment to be confirmed by a defect in excess thickness during a second treatment.

In addition, the speed of implementation of each second treatment is then improved.

According to a fourteenth aspect, the present invention relates to a weaving machine, caractéπsée in that it comprises an inspection device as succinctly set out above.

According to a fifteenth aspect, the present invention relates to a process ^for inspecting fabric, characterized in that it comprises

a first processing operation of each image representative signal supplied by a camera adapted to capture an image of a part of a fabric being scrolled to assess the presence of defects in the part of the fabric represented by said signal, and ,

- for each defect, the presence of which is thus assessed as probable, a second processing operation of at least one second signal representative of the tissue to confirm the presence of said defect.

The advantages of this process, this memory and this weaving machine being the same as those of the thirteenth aspect of the invention, they are not recalled here Vu. Seventh perspective

The present invention relates to a device and method for counting picks and controlling a fabric inspection system. It applies in particular to the characterization of pieces of fabric and to the automatic inspection of fabrics.

In a fabric, a transverse thread is called "dmte". At the fabπcaùon, this DMTE wire is inserted between the son kept by the machine blades weaving Thus, when ^a piece of cloth is fabπquée or inspected, each .duite is substantially perpendicular to the running direction of the fabric. Counting picks is interesting because, while the length of a fabric can vary depending on the humidity or the tension applied when the fabric is wound, the number of dmtes of the fabric only goes when the fabric is cut.

The currently known dmte counting devices use a light source q illuminates the tissue, an optical sensor which receives an image of the part of the tissue illuminated by the light source and an electronic device q processes the signal from the sensor to deduce information from the passage of dmte Electronic circuits are generally complex because of the poor quality of the optical signal collected by the optical sensor

The present invention intends to remedy these drawbacks To this end, the present invention relates, according to a sixteenth aspect, to a device for counting dmtes on a moving fabric, the device comprising

- a light source adapted to illuminate part of the fabric,

a light sensor coming from said part of the fabric adapted to emit an electrical signal representative of the quantity of light reaching said sensor, and

a circuit for processing the electrical signal from said sensor, adapted to emit an electrical signal comprising pulses, the number of which is representative of the number of picks passing in front of the sensor, characterized in that said illuminated part of the fabric has a width less than the pitch of the pick thread in said fabric.

Thanks to these arrangements, the optical signal which reaches the optical sensor varies greatly with the passage of the pick wire and the signal processing circuit coming from the sensor can be very simple while guaranteeing a precise counting of the picks.

According to particular characteristics, the light source is adapted to modulate the light intensity emitted towards the fabric by a modulation signal, and the processing circuit is adapted to demodulate said modulation signal. Thanks to these provisions, the effects of parasitic optical signals, for example sunlight or lighting of premises can be excluded from the signal from the optical sensor. The processing circuit is thus freed from ambient light by heterodyne detection on reception.

According to other particular characteristics, the light source comprises at least one coherent light source. Thanks to these provisions, the modulation of the emitted light can include high frequencies, which improves heterodyne detection. In addition, the chromatic dispersion of the treated light can be reduced. The device can thus be very simple while retaining very high reliability. According to other particular characteristics, the sensor has a maximum spectral sensitivity in the emission spectrum of the light source. Thanks to these provisions, the stray lights have a reduced effect compared to the light source.

According to other particular characteristics, the light source has a spectrum whose width is less than one tenth of its maximum frequency. Thanks to these arrangements, the chromatic dispersion of light is reduced and the wavelengths outside this spectrum can be filtered, which reduces the influence of parasitic light waves.

According to other particular characteristics, the sensor comprises a photosensitive surface and the device which is the subject of the present invention comprises an optical light concentration means suitable for concentrating the light coming from said part of the tissue on the photosensitive surface of said sensor. Thanks to these provisions, the sensitivity of the sensor is greater than it would be without optical means of concentration and very dark tissue can be treated.

According to other particular characteristics, the sensor includes a photodiode. Thanks to these provisions, the signal / noise ratio of the signal from the sensor is very high.

According to particular characteristics, the sensor comprises a photosensitive surface and an optical filter placed between the fabric and said surface, said filter being adapted to reduce the light intensity of light rays whose frequency is outside a predetermined frequency spectrum and the emission spectrum of the light source corresponds to the predetermined frequency spectrum of said filter. Thanks to these arrangements, the effects of stray light waves are reduced.

According to particular characteristics, the processing circuit includes a threshold circuit. Thanks to these provisions, detection of picks is particularly simple and the production cost of the device is reduced.

According to particular characteristics, a semi-reflecting mirror is used to confuse, near the fabric, the axes of the light source, on the one hand, and the optical sensor, on the other hand. According to particular features, the received signal is amplified ^before being detected, preferably with an automatic gain control circuit, so that variations in the reflection coefficients between tissues, are compensated.

According to a seventeenth aspect, the present invention relates to a fabric inspection device comprising the pick counting device exposed succinctly above, a linear camera and a circuit for triggering shots of said linear camera adapted to trigger taking pictures at a frequency representative of the frequency of passage of picks detected by the pick counting device.

According to an eighteenth aspect, the present invention relates to a method of counting picks on a fabric during scrolling, comprising:

- a light emission operation towards a part of the fabric,

an operation for capturing light coming from said part of the fabric and for emitting an electrical signal representative of the quantity of light captured, and

an operation for processing said electrical signal and transmitting an electrical signal comprising pulses the number of which is representative of the number of dmtes passing in front of the sensor, characterized in that said part of the fabric has a width less than the pitch of the wire pick.

This inspection device and this method have the same particular characteristics and the same advantages as the pick counting device succinctly described above. These particular characteristics and these advantages are therefore not recalled here. Brief description of the figures

The invention will be better understood on reading the description which follows, made with reference to the appended drawings in which: Vm. First perspective

- Figure 1 shows, in side view, a first assembly of the fault detection device;

- Figure 2 shows, in side view, a second set of the fault detection device partially illustrated in Figure 1; and

- Figure 3 shows schematically an electronic microprocessor circuit intended to process information, in the fault detection device illustrated in Figures 1 to 2. IX. Second to sixth perspectives

- Figure 4 shows, in side view, a fault detection device according to the present invention;

- Figure 5 shows optical fields of cameras incorporated in the device illustrated in Figure 4; - Figure 6 shows, schematically, an electronic microprocessor circuit for processing images, incorporated in the fault detection device illustrated in Figure 4; and

- Figure 7 shows an operating flow diagram of the circuit illustrated in Figure 6;

FIG. 8 represents optical fields on a fabric in the process of moving optical fields which correspond to images processed during the implementation of the flow chart illustrated in FIG. 7. X. Seventh perspective

FIG. 9 represents a device for counting picks according to the present invention,

- Figure 10 shows an optical part of the pick counting device illustrated in Figure 9, - Figure 11 shows a fabric inspection device according to the present invention, incorporating the optical part shown in Figure 10 and the illustrated electronic circuit in figure 10

Detailed description of the figures

XI. First perspective

In FIG. 1, are represented - a tissue dispenser 101, schematically represents in the form of a bob me of fabric in the course of unwinding,

- A fabric reel 102, schematically represents in the form of a reel of fabric being wound.

a camera 116, fitted with a lens 106, directed towards the strip of fabric placed between the unwinder 101 and the reel 102,

two light sources 103 and 105 adapted to illuminate the strip of fabric in the vicinity of the optical axis of the camera 106. on the same side of the fabric as this camera,

a light source 104 adapted to illuminate the strip of fabric in the vicinity of the optical axis of the camera 106, on another side of the fabric than that observed by the camera 106, - a pick-up account consisting on the one hand, a light source 109, placed on one side of the fabric strip located between the unwinder 101 and the reel 102, an optical sensor 107 placed on the other side of the fabric strip, and a circuit signal processing 108, connected to a computer 114, and on the other hand, an encoder 110 placed in contact with the fabric and following the movements of the fabric by rolling an encoder wheel, without sliding on the surface of the fabric , a pulse counter 111 connected to the output of the encoder 110 and to an input of the computer 114,

a magnetic label holder 112 adapted to place a magnetic label each time it receives an electrical pulse from an output of the computer 114,

- a computer screen 115 connected to the computer 114, and - a network link 113

The fabric unwinder 101 and the fabric rewinder 102 are of a type known in the textile industry. They are suitable for preventing the formation of folds on the surface of the fabric.

The camera 116 is a linear camera of known type. It has, for example, a linear sensor, that is to say of which all the elementary photosensitive surfaces (known under the name of "pixels") lie on a line L ' objective 106 is of known type II is suitable for focusing on the linear surface of the sensor of camera 116, an image of a line of the tissue substantially perpendicular to the direction of movement of the tissue and the length of which is at least equal to 95% of the width of the fabric strip

The light sources 103, 104 and 105 are of known type, for example made up of neon tubes, supplied by high-frequency electrical supplies themselves supplied by continuous electrical supplies The pick account is adapted to provide a signal each time a wire or a predetermined number of thread passes through its optical field. It is now observed that the composition of the pick account can incorporate a point light source and / or a point sensor, or an optical system allowing an area of the sensor to perceive only the light transmitted or reflected by a thread of the fabric, in the direction of the width (width) of the fabric.

The pick-up counter works on the principle of the joint analysis of two signals, one of which has a regular frequency but can have a deviation of a few percent (the signal from the encoder) and the other of which can locally present a lack of representation ^of a DMTE or rather irregular signal. Joint analysis of such signals is well known to those skilled in the art of signal processing.

The signal processing circuit 108 is of a type known for restoring a signal at the output of a captem 11 provides a cyclic signal of sufficient amplitude to allow its use by the computer 114 The encoder 110 and the pulse counter 111 provide a signal each time the encoder rotates at a predetermined angle, this signal having sufficient amplitude to allow its use by computer 114

The magnetic label holder 112 is of known type.

The computer system, computer screen 115 and computer 114, is detailed with reference to FIG. 3.

Finally, the network link 113 allows the computer 114 to communicate with a computer network, for production management. In figure 2, are represented ^•

- an unwinder to _^ tissue 201, shown schematically in the form of a coil being unwound fabric,

- a fabric reel 202, schematically represented in the form of a reel of fabric being wound,

- a source of oπentable laser beam 203, oπentée towards the strip of fabric placed between the unwinder 101 and the reel 102. - a light source 206 adapted to illuminate the strip of fabric in the vicinity of the optical axis at rest of the source of laser beam 203, on the other side of the tissue than that illuminated by the source of laser beam 203.

- a pick-up account consisting of a light source 204. placed on one side of the strip of fabric located between the unwinder 201 and the take-up reel 202. of an optical sensor 207 placed on the other side of the strip of fabric, and a signal processing circuit 208, connected to a computer 214, - an encoder 205 placed in contact with the fabric and following the movements of the fabric by rolling an encoder wheel. without sliding on the surface of the fabric,

a pulse counter 209 connected to the output of the encoder 205 and to an input of the computer 214,

a magnetic label detector 210 adapted to emit an electrical pulse each time a magnetic label passes through its detection field. a computer screen 213 connected to the computer 214. - a network link 212. and

- an alarm 211.

The laser beam source 203 is adapted to emit a visible laser beam towards a point of the tissue placed on a line perpendicular to the direction of travel of the tissue, with a lateral position on the tissue which varies as a function of an electrical signal. coming from the computer 214. For this purpose the laser beam source 203 comprises a mirror whose angular position, relative to an axis substantially parallel to the direction of travel of the fabric, is controlled by the electrical signal coming from the computer 214 The magnetic label detector 210 is of known type, with inductive sensor. In FIG. 3 are shown, in a computer system 30, linked together by a data and address bus 302, a central processing unit 306 consisting of a processor, a read-only memory 305, a random access memory 304 and an input / output port 303.

These elements are well known to those skilled in the art of computer systems and are therefore not more detailed here.

The input port output 303 is connected to - a keyboard 301, to receive instructions from the user,

the signal processing circuit 108,

- the network link 113,

the lighting power supply 309, the power of which is controlled by the computer system 30 to compensate for the respective variations in the transmission and reflection coefficients of the fabric to be inspected,

- The camera 116, which receives from the computer system 30, control signals for shooting and / or duration of shooting and / or frequency of shooting, and which returns to the computer system, digital signals successively representative of the quantities of light received by the photosensitive points of its linear sensor, - the magnetic label holder 112, and

- screen 115.

Read-only memory 305 stores, in a register, the operating program of the computer system 30 and in particular, the fabric inspection program described in patent FR-A-2,701,766 (Institut Textile de France, August 26, 1994) . The random access memory 304 stores in registers which, for convenience, have the same name as their content, variables, intermediate processing results and processing results of the operating program of the computer system 30.

The principle of the location using the pick account is as follows: each interesting point of the fabric, and in particular each defect is identified by the value of three counters: - the pick counter which is reset at the start of the fabric,

- the counter for the number of magnetic labels already identified, and

- the difference between the current value of the pick counter and the value of the same pick counter at the time of the most recent detection ^of a magnetic tag.

Xπ. Second to sixth perspectives In figure 4. are represented: - an unwinder ^to beam 401. schematically in the form of a current coil unwinding son

- a fabric reel 402. schematically represents in the form of a bobbin of fabric being wound up - twenty-four cameras 416A to 416X (the last twenty-three being in side view, masked by the first), ripe , each of a lens 426, and all substantially oriented towards the striking area of a comb 404 of a weaving machine (not shown),

a light source 403 adapted to illuminate the strip of fabric in the vicinity of the optical axis of the cameras 416A to 416X, on the same side of the fabric as these cameras, a blade 405,

- a blade 406,

a motor for setting in motion the comb 404 and the blades 405 and 406, q emits, cyc cally, an impulse, during the movement of these elements of the weaving machine,

a computer 414. a computer screen 41 connects to computer 414. and

- a network link 413>

The wire unwinder 401 and the fabric winder 402 are part of a weaving machine of the type known in the textile industry.

The cameras 416A to 416X, each consist of a known type of matrix camera. It has, for example, a monochrome matrix sensor, that is to say of which all the elementary photosensitive surfaces (known by the name of "pixels ") are on a rectangular table formed by rows and columns Each camera lens 426 is of known type II is adapted to focus on the photosensitive surface of the sensor of the camera with which it is associated, a sharp image of an area rectangular which surrounds the striking zone of the comb The optical fields of the cameras 416A to 416X overlap laterally (see FIG. 5) The cameras are, preferably, synchronized with each other, according to known techniques They carry out pπses of views simultaneously and simultaneously provide electrical signals representative of the quantities of light perceived during a view by all the photosensitive points of their sensor

The light source 404 is of known type. It is, for example, constituted by a neon tube, supplied by an electrical supply supplying a high frequency current, said supply being itself supplied by an alternative electrical supply (or, according to a preferential, continuous variant)

The computer system, comprising in particular the computer screen 415 and the computer 414, is detailed with reference to FIG. 6 Finally, the network link 413 allows the computer 414 to communicate with a computer network, for the management of the production

In FIG. 5, parallel threads 501 and 502 are shown intended to form the warp threads of a fabric (here a canvas), after a comb 404 has struck a weft thread 508 in the fabric already constituted. In FIG. 5 , the comb 404 is represented at the time of striking the wire 508 The cameras 416A to 416X observe an optical field 504, 505, 506, ..., in which the set of successive lines 509, 510, 521, ..., relate to the last weft thread 508 which was struck by the comb 404.

The optical fields of the cameras partially overlap in the direction perpendicular to the direction of movement of the fabric being woven.

It is observed that in the optical field of the camera 416B, there is a suspect wire 507. This wire is considered to be suspect, either because it has already been the subject of faults previously detected, or because, without being defective, he has a higher abnormality than the other sons. For example, this wire is very tight, very thin, etc. In FIG. 6 are represented, in a computer system 600, linked together by a data and address bus 602, a central processing unit 606 consisting of a processor, read-only memory 605, random access memory 604 and an input / output port 603.

These elements are well known to those skilled in the art of computer systems and are therefore not more detailed here. Input / output port 603 is connected to

a keyboard 601, to receive instructions therefrom from the user,

- network link 413,

each camera 416A to 416X, by means of a multiplexing and digitization card 607, which successively supplies a digital signal representative of the image captured by the sensor of each camera,

- screen 415,

- an input 609 of synchronization signals of the comb, on which a signal coming from the weaving machine and representative of the progress of at least one phase of the operating cycle of said weaving machine, is present, also called cyclic signal input from the motor 407, and - an output 615 to an electrical cabinet for controlling the weaving machine and in particular for stopping the weaving machine.

The read-only memory 605 stores, in a register “programJ”, the operating program of the computer system 600 and, in particular, the fabric inspection program illustrated in the form of a flowchart in FIG. 7. The random access memory 604 stores in registers (“/ ^' ” and “data”), variables, intermediate processing results and processing results of the operating program of the computer system 600.

The central unit 606 is suitable for implementing the program, part of which is shown in FIG. 7. In FIG. 7, there is observed, first of all, an initialization phase 701 known to those skilled in the art of the systems of computer-based image processing. During this phase, from data stored in memory or supplied by the user, via the keyboard 601, the central unit 606 performs the determination of thresholds, the width, the configuration of the digitization card. 607, its gain, its original offset (known to those skilled in the art under the English name "offset"), and the sequencing of cameras. Camera sequencing is ^the order in which the signals transmitted by the cameras are analyzed by ^the CPU 606. Preferably, the cameras 416A to 416x being numbered from 1 to 24, the sequencing starts, as a result of the positioning wire by comb 404,

- by the two extreme cameras, numbered 1 and 24, then - by eleven of the intermediate cameras, for example, 13, 3, 17, 7, 21, 11, 5, 19, 9, 23, 15, then,

- again, by the two extreme cameras numbered 1 and 24, then

- by the remaining eleven intermediate cameras 14, 4, 16, 6, 20, 10, 18, 8, 22, 12, 2.

However, this sequencing is dynamically modified: when ^a fault is detected in the optical field of one of the cameras: - immediately after a new image taken by said camera is analyzed to confirm the presence or infiπner of a defect,

- the camera concerned is considered to be watching a suspicious area.

The sequencing then becomes:

- by the two extreme cameras, numbered 1 and 24, then - the camera which observes the most suspect area,

- by eleven intermediate cameras, for example, 13, 3, 17, 7, 21, 11, 5, 19, 9, 23, 15, with the exception, if necessary, of the camera which observes the most suspicious, then,

- again, by the two extreme cameras numbered 1 and 24, then

- again by the camera which observes the most suspect area, - by the eleven remaining intermediate cameras 14, 4, 16, 6, 20, 10, 18, 8, 22, 12, 2 except, if applicable , from the camera which observes the most suspicious area.

Alternatively, two cameras are considered suspicious and are inserted into the sequence instead of the only camera considered suspicious in the example above:

- the last camera in the field of which a fault has been detected and confirmed after analysis of the second image,

- the last camera in which a defect was detected field but ^has not been confirmed after analyzing the second image.

More generally, the central unit 606 is adapted to more frequently process an image representative signal leaving one of the cameras than an image representative signal leaving another camera.

To this end in the particular embodiment of the invention illustrated in the figures, the CPU 606 performs a probable position estimation operation ^of at least one defect on said fabric, processes more frequently a representative image signal out of each camera corresponding to a said fault position probable that ^a signal from another camera. In the sequencing presented above, which is preferred when ^one redoubt on a loom given, tissue edge defects, the CPU 606 considers that the edges of the fabric are likely positions of defects.

The central unit 606 then performs a sequencing of the cameras to organize an order of cameras whose images are successively processed by it. As we have ^seen. ^the CPU 606 also considers that the position or the processing means has detected a defect that causes a machine stop is a probable default position.

Returning to the description of FIG. 7. next, the central unit 606 determines, during a test 702, whether the cyclic signal originating from the motor 407 has been received or not This cyclic signal is representative of a position of the comb in the operating cycle of the weaving machine. When the result of test 702 is negative, it is repeated

When the result of the test 702 is positive, the central unit 606 performs, during an operation 703, a timeout. that is to say, it waits for a predetermined duration to elapse. This duration makes it possible to wait for the comb to be stopped or, at least, for the movement of the tissue induced by the striking of the comb to be completed. During the same operation 703. the intermediate variable /. q represents the rank in the sequence, is initialized to the value 1.

During an operation 704, the central unit 606 stores the images simultaneously from all the cameras 416A to 416X. Then, during ^an operation 705, a portion of the image from the camera referenced to the / th row of the sequence determined during phase 701 is processed according to a qm algoπthme depends on its position: extreme cameras referenced 416A or 416X, or again 1 and 24, give rise to image processing intended to detect edge defects (correct width, thread tucked in, thread breakage, thread qm exceeds, edge tucked in too much, ...) then that the other cameras are subject to another image processing (edge, warp or weft faults and local faults).

These image processing operations are well known to those skilled in the art and are therefore not detailed here. As an example, patent application FR-A-2 701 766 (Institut Textile de France, August 26, 1994) details some of these image processing algorithms.

It is observed here that it is not the whole of each image which is processed during the operation 705 but only the central band, excluding the upper and lower bands q corresponding to a part of the tissue whose image is processed in a further operation 705. the height of the fabric web processed corresponds in fact to approximately the length of woven fabric between two treatments ^of successive pixels applied to two images from the same camera.

Thus, the central unit 606 makes a selection, for each camera, of an image part, and only processes said image parts to detect therein at least one weaving defect, during operation 705. In the embodiment decπt and shown, the optical fields of the cameras extend jointly over the entire width of the fabric to be inspected (see FIG. 5) and the selection of parts of images carried out by the central unit selects parts of ^' images that. jointly extend over the entire width of the fabric to be inspected

Then, during a test 716, the central unit 606 determines whether a fault has been detected during operation 705. or noα

When the result of test 716 is negative, an operation 711 is further determined. When the result of test 716 is positive, a defect was detected during operation 705 but, in accordance with the thirteenth to fifteenth aspects of the present invention, the presence of this defect is then considered or estimated only as probable and must be confirmed For this purpose during a test 717. the central unit 606 performs the immediate memoπsaûon of a new image pπse by the camera whose rank in the sequence is; Then, still during test 717. part of this image which contains the defect assumes as probable (see Figure 8) esLtraitee by implementing the same detection fields as during operation 705 If a fault of the same type and same position, on the fabric, that the fault detects during operation 705 is detected, the fault is considered to be confirmed and a test 706 is carried out If, on the contrary, no fault of the same type and substantially the same position, on the fabric, that the one detected during the operation 705, is not detected during the test 717, the central unit 606 considers that the defect in question does not exist on the fabric and the operation 711 decπte below is performed for each fault detects and confirms its position in the image to determine ^if it has already been landmark in the analysis of another image (pπse by another camera), and what he DMTE lies The position, along two axes, of this defect, as well as part of the last image (pπse during test 717) that surrounds it and the parameters of the detected fault, are stored in memory by the central unit 606

When ^a fault is detected and confirmed, camera sequencing is modified so that pπses pictures from the camera are considered the analyzed twice as often as pπses pictures from other cameras, with the exception of extreme cameras and possible other "suspicious" cameras. knowing that, preferably. the number of "suspicious" cameras is limited to one or two

In accordance with a fifteenth aspect of the present invention, the fabric inspection process comprises - a first operation of processing each image signal signal provided by a camera adapted to capture an image of part of a fabric in during running, to assess the presence of defects in the part of the fabric represented by said signal and,

- for each defect, the presence of which is thus evaluated as probable, a second operation for processing at least one second signal representative of the tissue to confirm the presence of said defect. several signals corresponding to several so-called second images, can successively be processed to confirm the presence of a fault

In the embodiment decπt and represents, during the first processing operation 705 and during each second processing operation 717, the parts of the tissue represented by the first signal representative of image and by each second signal representative of image have a non-empty intersection in which the defect is considered likely (see figure 8)

According to a variant, particularly adapted to the types of defects which πsquent to reproduce at each step of the fabric, the part of fabric represented by each second image representative signal is located one or more steps from the part of the fabric represented by the first signal representative ^of addresses picture

In the mode of rehsation decπt and represented. each processing operation, 705 and 717, is carried out taking into account the evaluation or confirmation cπteres of the presence of a defect and during each second processing operation 717, the same confirmation cπteres are used as during of the first processing operation 705 such that a representative image signal which, during the first treatment operation presents a probable presence of defect also presents, during each second treatment confirmation of said defect.

According to a variant not shown, during the first processing operation 705, a type, among a plurality of fault types, is assigned to each fault whose presence is evaluated as probable, and during each second processing operation, 717 , criteria for confirming the presence of a fault are used which depend on the type of fault assigned to the fault during the first processing operation.

When the result of the test 717 is positive, during a test 706, ^the CPU 606 determines whether a fault of one of predetermined types (thread breakage, ...) or ^of a predetermined size (dimension greater than a limit value, contrast with the tissue greater than another limit value) was detected, and validated, during operation 705.

When the result of test 706 is positive, the weaving machine is stopped, operation 707.

Then, during a test 708, the central unit 606 determines whether or not the defect can be repaired by weaving and reweaving. When the result of test 708 is positive, the weaving machine performs the weaving and reweaving of the fabric. to the fault position and repair of the fault during an operation 709.

When the result of test 708 is negative, the central unit 606 triggers an alarm (flashing light, sound signal or computer message on a computer network comprising the part of the image on which a fault has been detected), during a operation 710. Each time the weaving machine is restarted after an operation 710, the central unit 606 performs operation 711, while keeping in memory the images which had been captured and memorized just before the machine stopped (operation 707) . After a few cycles each comprising image analysis of a whole sequence of cameras, the CPU 606 performs operations identical to the operations 702-704, and an ^image processing of comparing the luminance ( "levels ") of warp threads before and after machine stop.

Preferably, this comparison n ^'is performed on the images from the camera i, ^one of which caused the machine stop. Alternatively, all cameras are considered.

For each camera, two images are compared, knowing that two very different colors may correspond to grayscale or very similar luminance, ^the CPU 606 averages the gray levels along the chain son, outside the area where a fault had been detected.

We know that, except in the event of a defect in the positioning of the optical axis of the camera lens perpendicular to the plane of the area of the tissue inspected, the warp threads correspond to vertical columns in the raster images. Also, the averages compared here are those of the gray levels on each vertical column of photosensitive dots, between the two images taken by the same camera (except in the zone where the defect was detected, which is excluded from the average, so that the default does not distort the average considered). Thus, when ^the operator puts a warp but the wrong color, the device detects the error and causes a new machine stop by storing not ^the most recent image but one that had preceded the first of two weaving machine stops. Following this positioning defect bad search warp, operation then resumes al ^'705 transaction with the same value of /

When the result of test 706 is negative or following the operation 709. the vaπable / is incremented by one step equal to 1 during an operation 711 during ^a test 712, the central unit 606 determines if the value of the variable / is equal to

14. or not When the result of test 712 is positive an image pπse by each of the cameras 1 and 24 is again memoπsee, operation 714 and operation 705 is repeated

When the result of the test 712 is negative, during ^a test 713, ^the CPU 606 détermme if the value of the vaπable / stπctement supéπeure is 26 or not when the result of the test 713 is negative the operation 705 is repeated When the result of test 713 is positive, test 702 is repeated

When ^the final judgment of the machine, at the end of weaving a fabric roll, the CPU 606 automatically edits a q visit sheet contains information about detected defects q have not been repaired and, possibly, the other detected faults This visit sheet is transmitted on a computer network intended for production management In FIG. 8, the optical fields corresponding to different images captured by the cameras 416A to 416C are observed, assuming that, during an operation 705. a fault 805 is considered probable in the optical field of the camera 416B.

The fabric 801 scrolling from top to bottom, a first sequence of images is stored in random access memory 604, the optical field of the camera 416A being referenced 802, that of the camera 416B being reference 803 and that of the camera 416C being referenced 804

When ^a defect 805 is detected in operation 705, in operation 717 qm film succeeds, an image from the camera 416B is mémoπsée RAM 604 This image has a field of view 806 is shifted qm, relative to the field 803 in the opposite direction to the running direction, as the fabric 801 ^s' is moved between the pπses corresponding views is observed that the optical field 806 provides an alleged defect image 805 to this end

- firstly, the distance traveled by the tissue is înféπeure to the distance between an edge of the corresponding optical field at the ^image portion processed during the operation 705 and the edge of the field 803, and

- secondly, the portion of the image being processed is modified to reflect the movement of the fabric, displacement provided by ^the encoder or the account DMTE

According to a not shown vaπante, the pπse of view for the memonsatton of an image is carried out under control of CPU 606 F ^The operation 704 then comprises said trigger as soon as the fabric is stopped

According to a variant, the central unit 606 successively considers the cameras in the optical field of which the most suspect wires are found, in a decreasing order of suspicion.

According to a variant. the device covered by the present invention as ^that described above is dissociated to a loom but associated with a cutting table cloth To this end the comb synchromsation signals are replaced by a signal on the synchromsation scroll tissue under the cameras, for example from ^an encoder in the cutting tables of fabric, such as the brand French registered LECTRA SYSTEMS the cutting instruments are laser wheels or water jets

The implementation of the present invention then allows the operators ^to be alert to the presence of defects and to identify these defects and, in the case of automatic cutting tables, the parts position determination software has cut, to control cutting the pieces of fabric outside the defective areas identified by the XH device Seventh perspective

In the dmtes counting device 901 in accordance with the present invention and illustrated in FIG. 9. a tissue 910 is moved in movement between an unwinder 920 and a winder 930 An optical part 940 of the device (illustrated in FIG. 10) provides a signal a an electronic circuit 950 which provides, on a port input / output 960, a number of credited dmtes a computer 970, provided with ^a keyboard 971, ^a screen 972, a label printer 973 and a 974 network interface connected to a production management system not shown

The computer includes a processor 975, a RAM 976 and a non-volatile memory 977 retains instructions q ^a qm program implemented by the processor 975 enables the operation of the following MAMERE When dmtes metering device ^' a new piece of fabric is to be treated, the Fuùiiseur indicates this by pressing a key 980 specifically dedicated to the keyboard 971, in correspondence with a user interface of known type (not shown here) The processor 975 then stores in a register “ metial number "of the RAM 976, the number of dmtes provided by the circuit 950 on the input / output port 960 and înitia is zero a register" retained "in RAM 976

During the countdown of the number of dmtes of the piece of fabric, each time the number of dmtes supplied by the circuit 950 reaches the maximum value that the circuit 950 is capable of supplying, the processor 975 increments the value kept in the register "Hold" of this maximum number

When the running of the fabric piece is completed, which is indicated by the user by ^depressing a specifically dedicated key 981 key 971, the processor 975 memorizes in a register "_final number" of the RAM 976, the number of dmtes supplied by the circuit 950, then the processor 975 adds the value kept in the registers "Jnal number" and "retained" and subtracts from this sum the value kept in the register "initial number" and stores in memory the result in a “counted picks” register of the RAM 976 Finally, the processor 975 prints a self-adhesive label or not bearing the mention “number of meters” followed by the value kept in the “counted picks” register and transmits to the system of production management the value kept in the “counted picks” register

In the optical part 940 of the pick counting device 901. part illustrated in FIG. 10, there is a light source 1000, a lens 1010 the fabric 910, a lens 1020. a photoelectronic sensor 1030. and the processing circuit 950

The light source 1000 includes a electπque supply 1001, a 1002 modulator and a 1003 L laser diode ^lens 1010 focuses the light from the laser diode 1003 on a portion of fabric 990 having a width, dimension perpendicular to dmtes a count is înfeπeure to the pitch of the dmte thread in the fabric The length of the part of the fabric 990 lit by the laser diode 1003. dimension parallel to the dmtes. is equal to at least two steps of the wire perpendicular to the meters The photo-electronic sensor 1030 comprises a 1032 adjusts color filter selectively passing the ^wavelength of the light ravons from the laser diode 1003 and a photodiode 1031 L 1020 objective concentrated by said portion of reflected light of the tissue on the photosensitive surface of the photodiode 1031 circuit processing 950 includes an automatic gain control circuit 951, a demodulator 952, a threshold circuit 953 and a pulse counter 954

According to a variant. the modulator 1002 and the demodulator 952 are fitted in such a way that the demodulator 952 demodulates the signal modulated by the modulator 1002 and extracts the other signals present in the signal coming from the photodiode 1031

All the elements illustrated in FIG. 10 are of known type and are therefore not described in more detail here. Each time a pick passes through the illuminated part of the fabric, the change in direction of reflection of the light causes a variation in the light signal coming from the laser diode 1003 and received by the photodiode 1031 the ^intensity of this signal passes, at each passage cycle ^of a DMTE in the illuminated portion, by a maximum and a minimum

The signal demodulated resultant is calibrated with automatic control circmt gain 951 and, at each crossing of circmt the threshold line 953, which signal causes ^the incrementation of the value displayed by the ^pulse counter 954, port input / output 960, after this value has been conditioned to take a form of logic signal which can, for example, be of the “TTL” type

What is called here “part of the fabric” 990 is, in fact, the intersection of the area illuminated by the laser diode 1003 and the area of the fabric transmitting light to the photosensitive surface of the photodiode 1031 It has substantially a rectangular shape of width (in the direction perpendicular to the dmtes) inferior to the pitch of the smallest dmte threads that the dmte counting or tissue inspection device is intended to detect

The inspection device of tissue 1100 accordance with the present invention Ulustre in Figure 11 includes all items shown in Figure 9, as well as ^a line camera 1110 with a lens 1120, a light source 1130 and a electromque circmt d 1140 and a control circuit 1150 of the views of the hneaire camera 1110

Hneaire the camera 1110 is of known type comprises a photosensitive It hneaire fourmt sensor and a signal representative of the image ^of a line across the fabric 910 The objective 1120, of known type, formed on the surface of the photosensitive linear sensor a clear image of said transverse line The light source 1130 illuminates said transverse line in a continuous manner The control circuit 1150 is connected to the output of the threshold circmt 953 (not shown) and controls each view of the linear camera 1110 a the same phase value in the DMTE passing cycle, for example at each rising edge of the signal from the circmt a threshold 953 in this MAMERE, ^the pπse image by the line camera always represents the same phase of the pitch of the fabric, as set out in European patent application 95939316 6 and, by simply subtracting the numerical values of two images taken successively, certain fabric defects are detected

According to a variant. the light source 1003 ^is not a laser diode but has a narrow spectral range, for example inféneure a tenth of its maximum value

According to a not shown vanante, a half mirror is used to confuse, close to the fabric, the axes of the light source and / or ^the q objective focuses the light from somce of the light on the tissue, on ^the one hand and CAPTEM phto-electronics and / or the lens that focuses light reflected by the tissue on the optical CAPTEM the other hand.

According to another variant not shown, the received signal is amplified ^before being detected, preferably with an automatic gain control circuit, so that variations in the reflection coefficients between tissues, are compensated.

Claims

1. A device for inspection of tissue, characterized in that ^it comprises:

- at least one camera (416A to 416x) adapted to capture an image ^of a part of the fabric (801) being scrolled and outputting a signal representative of the captured image, and

- a processing means (604, 605, 606) adapted to process a first time (705) each image representative signal, and to evaluate the presence of defects in the part of the tissue represented by said signal and, for each defect whose the presence is thus evaluated as probable, to process at least a second signal representative of the tissue to confirm the presence of said defect (717).

2. A tissue inspection device according to claim 1, characterized in that the processing means (604, 605, 606) is adapted so that the parts of the tissue represented by the first image representative signal (803) and by each second image representative signal (806) have a non-empty intersection in which the defect (805) is considered to be probable.

3. Fabric inspection device according to any one of claims 1 or 2, characterized in that the treatment means (604, 605, 606) is adapted so that each second treatment

(717) is performed with the same criteria as the first processing (705), so that a representative image signal which, during the first processing has a probable presence of defect, also presents, during each second processing, confirmation of said defect.

4. Fabric inspection device according to any one of claims 1 or 2, characterized in that the treatment means (604, 605, 606) is adapted so that:

the first processing (705) assigns a type, among a plurality of fault types, to each fault whose presence is evaluated as probable, and

- Each second treatment (717) is carried out with criteria for corifirmation of the presence of defect which depend on the type of defect attributed to the defect during the first treatment.

5. Weaving machine, characterized in that it includes an inspection device according to any one of claims 1 to 4.

6. Fabric inspection process, characterized in that it comprises:

a first processing operation (705) of each image representative signal supplied by a camera (416A to 416X) adapted to capture an image of a part of a fabric (801) during scrolling, in order to evaluate the presence defects in the part of the tissue represented by said signal and,

- For each defect whose presence is thus evaluated as probable, a second processing operation (717) of at least one second signal representative of the tissue to confirm the presence of said defect.

7. A fabric inspection method according to claim 6, characterized in that during the first processing operation (705) and during each second processing operation (717), the parts of the fabric represented by the first signal representative image (803) and by each second image representative signal (806) have a non-empty intersection in which the defect (805) considered to be probable is found.

8. A fabric inspection method according to any one of claims 6 or 7, characterized in that each treatment operation (705, 717) is carried out taking into account criteria for evaluating or confirming the presence of a defect and in that during each second processing operation (717), the same confirmation criteria are used as during the first processing operation (705), such so that an image representative signal which, during the first processing operation presents a probable presence of defect, also presents, during each second processing, a confirmation of said defect.

9. A fabric inspection method according to any one of claims 6 or 7, characterized in that:

- each processing operation (705, 717) is carried out taking into account criteria for evaluation or confirmation of the presence of a defect; - during the first processing operation (705), a type is assigned, from among a plurality of fault types, to each fault whose presence is evaluated as probable, and

- During each second processing operation (717), criteria for confirming the presence of a fault are used which depend on the type of fault assigned to the fault during the first processing operation.