CN111307723B - Magnetic rotation diaphragm, magneto-optical sensor, and weld joint detection device and method - Google Patents
Magnetic rotation diaphragm, magneto-optical sensor, and weld joint detection device and method Download PDFInfo
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Abstract
The invention discloses a magneto-optical rotation membrane, a magneto-optical sensor, a welding seam detection device and a method, which solve the problems that the quality of magneto-optical images is low, the light source irradiation area is small, two-dimensional scanning is needed, and the detection precision of welding seam defects is low in the prior art; the technical scheme is as follows: the magnetic rotation film comprises a magnetic rotation medium layer, wherein a first reflecting layer is arranged on one side of the magnetic rotation medium layer, and a second reflecting layer is fixed on the other side of the magnetic rotation medium layer; the second reflecting layer is matched with the first reflecting layer to increase the reflection times of polarized light.
Description
Technical Field
The invention belongs to the technical field of nondestructive detection of welding seams, and particularly relates to a magneto-optical rotation diaphragm, a magneto-optical sensor, a welding seam detection device and a welding seam detection method.
Background
Welding, one of the most important techniques in the field of manufacturing, is closely related to the quality and service life of the equipment. Because the working environment of the weldment is severe mostly, the defects on the welding seam can directly cause the damage of the weldment and influence the safety and the service life of equipment, the nondestructive testing technology for detecting the defects of the welding seam has very important significance. At present, the home and abroad nondestructive detection technologies comprise a magnetic powder detection method, a penetration detection method, a ray detection method, an eddy current detection method and the like, but the detection methods have certain limitations and defects.
In recent years, the weld joint detection technology based on the magneto-optical imaging principle, namely the detection technology that the magnetic field generator induces a magnetic field on a weldment and then a magneto-optical sensor acquires magneto-optical images of the weld joint, has the characteristics of no damage, high precision, high efficiency, safe use and the like, well overcomes the defects of the various detection methods, and is widely applied to weld joint nondestructive detection.
In the present research of performing weld joint detection by using a magneto-optical imaging principle, for example, a method and a device for detecting defects of a metal weldment disclosed in CN 107831211 a, for example, a weld joint texture nondestructive detection system disclosed in CN 107036973 a, for example, a laser weld joint detection device based on a magneto-optical sensor disclosed in CN 108526745A, for example, a workpiece defect detection system disclosed in CN 108918657 a, and the like, similar design schemes are adopted, that is: 1) adopting a surface light source as a polarized light source, and separating incident light and emergent light through a light splitter; 2) the magneto-optical rotation diaphragm which can only reflect once is used as the optical rotation device.
The inventor finds that when the surface light source is used as a polarized light source, incident light and emergent light can only be coaxially arranged perpendicular to a detection plane during structural design, the emergent light and the incident light can interfere with each other, and the light intensity can be greatly reduced when the incident light and the emergent light are separated by the light splitter, which affects the imaging quality. In practical design, in order to reduce magnetic resistance, the thickness of the magneto-optical rotation diaphragm is designed to be very thin, so that a single reflection can cause a small rotation angle of polarized light after passing through the magneto-optical rotation diaphragm, and detection precision and resolution are affected.
Disclosure of Invention
In view of the shortcomings of the prior art, it is a first object of the present invention to provide a magneto-optical film that improves the resolution of a magneto-optical sensor by enlarging the rotation angle of polarized light.
The second purpose of the invention is to provide a magneto-optical sensor, which adopts a line light source and solves the problems of low magneto-optical image quality and small light source irradiation area.
The third purpose of the invention is to provide a welding seam detection device, which realizes the full coverage of the welding seam detection in the length direction.
The fourth purpose of the invention is a weld joint detection method, which improves the magneto-optical image resolution and the weld joint defect detection precision.
In order to achieve the purpose, the invention is realized by the following technical scheme:
in a first aspect, an embodiment of the present invention provides a magnetic rotation diaphragm, including a magnetic rotation medium layer, where a first reflective layer is disposed on one side of the magnetic rotation medium layer, and a second reflective layer is fixed on the other side of the magnetic rotation medium layer; the second reflecting layer is matched with the first reflecting layer to increase the reflection times of polarized light.
As a further implementation mode, a protective layer is arranged on one side, away from the magneto-optical rotation medium layer, of the first reflecting layer. The first reflecting layer and the second reflecting layer have the same thickness, and the thickness of the protective layer is smaller than that of the second reflecting layer.
In a further implementation, the width of the second reflective layer is equal to the width of the magneto-optical rotation medium layer, and the width of the first reflective layer is smaller than the width of the magneto-optical rotation medium layer.
In a second aspect, an embodiment of the present invention further provides a magneto-optical sensor, including a housing, and a line laser emitter, an analyzer, a CCD camera and the magneto-optical rotation diaphragm mounted inside the housing, wherein the line laser emitter is located on one side above the magneto-optical rotation diaphragm, and the analyzer is located on the other side above the magneto-optical rotation diaphragm; the CCD camera and the analyzer are arranged coaxially.
As a further implementation mode, the line laser emitter and the CCD camera are respectively connected with the inner wall of the shell in a rotating mode.
In a third aspect, the embodiment of the present invention further provides a weld detecting device, including a magnetic field generator, a linear motion device and the magneto-optical sensor, where the magneto-optical sensor is disposed above the linear motion device and connected to a computer; the magnetic field generator is positioned below the magneto-optical sensor and can move along with the linear motion device.
As a further implementation manner, the linear motion device comprises a motion platform for placing a weldment, and the motion platform is connected with a motor through a lead screw; the magnetic field generator is fixed above the motion platform. The motor and the computer are respectively connected with the main control board.
In a fourth aspect, an embodiment of the present invention further provides a weld joint detection method, where in detection, a magnetic field generator with alternating current is used to perform alternating excitation on a weldment, and a magneto-optical sensor emits polarized light to a weld joint in the excited weldment and reflects the polarized light;
the CCD camera collects light strip images containing weld defect information and transmits the light strip images to the computer, the computer controls the motor to drive the moving platform to move at a constant speed through the main control board, the moving platform drags a weldment to enable the weld to pass below the magneto-optical sensor at a constant speed, and the magneto-optical sensor collects light strip images of different parts of the weld;
the magneto-optical sensor transmits the collected light bar image to the computer, and the computer processes the light bar image to obtain a complete weld image.
The beneficial effects of the above-mentioned embodiment of the present invention are as follows:
(1) the upper surface and the lower surface of the magneto-optical rotation membrane of one or more embodiments of the invention are plated with the reflecting films, the passing path of polarized light in the membrane is prolonged through the multiple reflection action of the reflecting films, and the rotating angle of the polarized light is increased under the condition that the thickness of the magneto-optical rotation membrane is not increased;
(2) one or more embodiments of the invention use a linear light source as a polarized light source, and different light paths are adopted for emergent light and incident light, thereby avoiding the mutual influence between the emergent light and the incident light; a light splitter is not needed, so that the light intensity attenuation in the light splitting process is reduced; thereby greatly improving the imaging quality; the light strip emitted by the light source can transversely cover the welding seam, and the magneto-optical sensor only needs one-dimensional scanning to detect the whole welding seam, so that the efficiency is higher;
(3) the detection device of one or more embodiments of the invention comprises a linear motion device, so that the linear laser transmitter and the detected welding seam do relative movement, and the full coverage of the welding seam detection in the length direction is realized;
(4) in one or more embodiments of the invention, a linear laser emitter emits strip-shaped polarized light, a polarized light strip is incident into a magnetic rotation film, the emitted polarized light passes through an analyzer and then is collected by a CCD camera, the CCD camera transmits a light strip image containing weld defect information to a computer, and the computer splices a plurality of light strip images into a complete weld defect image; the magneto-optical image resolution and the weld defect detection precision are improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.
FIG. 1 is a schematic diagram of the Faraday magneto-optical effect;
FIG. 2 is a prior art single reflection magneto-optical imaging principle;
FIG. 3 is a schematic diagram of a configuration of a magneto-optically active membrane in accordance with one or more embodiments of the invention;
FIG. 4 is an enlarged view of a portion of a magneto-optically active membrane in accordance with one or more embodiments of the invention;
fig. 5 is a schematic diagram of a magneto-optical sensor configuration in accordance with one or more embodiments of the invention;
FIG. 6 is a schematic diagram of the operation of a laser transmitter in accordance with one or more embodiments of the invention;
fig. 7 is a schematic diagram of a magneto-optical sensor in accordance with one or more embodiments of the invention;
FIG. 8 is a schematic diagram of a detection device according to one or more embodiments of the present invention;
the device comprises a first reflecting layer, a second reflecting layer, a protective layer, a shell, a first reflecting layer, a second reflecting layer, a third reflecting layer, a fourth reflecting layer, a fifth reflecting layer, a sixth reflecting layer, a fourth reflecting layer, a sixth reflecting layer, a fifth reflecting layer, a sixth.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an", and/or "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof;
for convenience of description, the words "up", "down", "left" and "right" in this application, if any, merely indicate correspondence with the directions of up, down, left and right of the drawings themselves, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.
The terms "mounted", "connected", "fixed", and the like in the present application should be understood broadly, and for example, the terms "mounted", "connected", and "fixed" may be fixedly connected, detachably connected, or integrated; the two components can be connected directly or indirectly through an intermediate medium, or the two components can be connected internally or in an interaction relationship, and the terms can be understood by those skilled in the art according to specific situations.
The first reflecting layer and the second reflecting layer are both reflecting films.
The first embodiment is as follows:
the embodiment provides a magnetic rotation membrane, which aims to solve the problem that the Faraday rotation angle is small due to the small thickness of the magnetic rotation membrane.
The principle of magneto-optical imaging is based on the faraday magneto-optical rotation effect, as shown in fig. 1, the polarization direction of polarized light will rotate by a certain angle when passing through an optical rotation medium with an external magnetic field, the rotation angle is called as faraday rotation angle θ, and the rotation angle is proportional to the passing path d of light wave in the medium and the magnetic induction intensity component B in the propagation direction of light in the optical rotation medium, that is:
θ＝V×B×d
in the formula: v is a coefficient characterizing magneto-optical properties, which depends on the material properties of the magneto-optically active medium and the wavelength of light operation, and is called Verdet constant.
As shown in fig. 2, in the conventional magneto-optical imaging detection scheme, light emitted from a light source 19 is converted into polarized light by a polarizer 20, and then is vertically incident into a magneto-optical rotation film 7 through a beam splitter 21. The weldment is arranged above the electromagnetic source 18, an induced magnetic field conducted after the weldment is magnetized exists in the magneto-optical rotation membrane 7, after primary reflection of the lower surface reflection film 22, polarized light is reflected back to the optical splitter 21 along the opposite direction of incidence, enters the analyzer 8 after being reflected by the optical splitter 21, and is finally collected by the CCD camera 9.
According to the faraday magneto-rotation effect, the polarization direction of polarized light is rotated in the magneto-rotation film 7 to which the induced magnetic field is applied, and the faraday rotation angle:
θ＝2V×B×h
in the formula: h is the thickness of the magneto-optical rotation diaphragm 7, and B is the component of the magnetic induction intensity in the magneto-optical rotation diaphragm 7 in the light propagation direction.
When designing the magneto-optical rotation diaphragm 7, in order to reduce the magnetic resistance of the magneto-optical rotation diaphragm 7 and increase the magnetic induction intensity in the magneto-optical rotation diaphragm 7, the thickness h of the magneto-optical rotation diaphragm 7 is often designed to be small, so that the faraday rotation angle θ is small and the magneto-optical rotation effect is not obvious. The weld joint detection method adopting the design scheme has relatively low precision and resolution.
The magneto-optical rotation film structure of the present embodiment is shown in fig. 3 and fig. 4, and includes a first reflective layer 1, a magneto-optical rotation medium layer 2, a second reflective layer 3 and a protective layer 4, which are sequentially disposed from top to bottom (with reference to the use state), where the first reflective layer 1 is used for reflecting polarized light to prevent light from escaping; the magneto-optical rotation medium layer 2 can conduct magnetism and change the polarization direction of polarized light; the second reflecting layer 3 is used for reflecting polarized light to ensure that the polarized light does not escape from the magneto-optical rotation medium layer 2; the protective layer 4 protects the magneto-optical rotation membrane.
The thicknesses of the first reflecting layer 1 and the second reflecting layer 3 are the same, and the thickness of the protective layer 4 is smaller than that of the second reflecting layer 3. The width of the second reflecting layer 3 is equal to the width of the magneto-optical medium layer 2, the width of the first reflecting layer 1 is smaller than the width of the magneto-optical medium layer 2, and the design scheme can ensure that polarized light can enter the magneto-optical medium layer 2 from one side of the first reflecting layer 1 at an angle alpha, and after multiple reflections through the first reflecting layer 1 and the second reflecting layer 3, the polarized light exits the magneto-optical medium layer 2 from the other side of the first reflecting layer 1, and the principle is shown in fig. 7. In practical applications, the width L is determined according to the following formula:
L>(N+1)×h×tanα
in the formula: n is the number of times of reflection of the polarized light, h is the thickness of the magneto-optical rotation film 7, and alpha is the incident angle of the polarized light.
In this embodiment, the thickness of the first reflective layer 1 and the second reflective layer 3 is 0.2mm, the thickness of the magneto-optically active dielectric layer 2 is 1mm, and the dielectric material is rare earth garnet. The thickness of the protective layer 4 is 0.1mm, and a material with good wear resistance, such as silicon nitride (Si3N4) is selected. It is understood that in other embodiments, the thicknesses of the first reflective layer 1, the second reflective layer 3, the magneto-optically active medium layer 2 and the protective layer 4 may be other values, and are set according to actual requirements.
Compared with a magneto-optical rotation membrane which can only provide single reflection, the magneto-optical rotation membrane has the advantages that the reflection times of polarized light in the magneto-optical rotation membrane are increased, the passing path of the polarized light in the membrane is prolonged under the condition that the thickness of the magneto-optical rotation membrane and the magnetic induction intensity in the membrane are not changed, and then the Faraday rotation angle of the polarized light is increased.
Example two:
the present embodiment provides a magneto-optical sensor, as shown in fig. 5, comprising a housing 5, a line laser emitter 6, an analyzer 8, a CCD camera 9, and a magneto-optical rotation film 7 according to the first embodiment, since the light emitted from the line laser emitter 6 is polarized light, there is no need for a polarizer to convert the light into polarized light. The shell 5 is a closed structure, and a cavity for mounting the line laser emitter 6, the analyzer 8, the CCD camera 9 and the magneto-optical rotation membrane 7 is formed in the shell. In the present embodiment, the housing 5 has a rectangular parallelepiped structure, and it is understood that in other embodiments, the housing 5 may have other shapes, such as a spherical shape, as long as the above components can be mounted and the mounting position can be ensured.
In the embodiment, the magneto-optical rotation membrane 7 is fixed on the bottom surface of the shell 5, the line laser emitter 6 is positioned on one side above the magneto-optical rotation membrane 7, and the analyzer 8 is positioned on the other side above the magneto-optical rotation membrane 7; the CCD camera 9 is positioned about 5-10mm behind the analyzer 8 and is arranged coaxially with the analyzer 8. As shown in fig. 5, the line laser transmitter 6 is mounted on the side wall of the housing 5 and is hinged thereto; the CCD camera 9 is hinged on one end of the top surface of the shell 5 far away from the line laser emitter 6.
The working principle of the magneto-optical sensor of the present embodiment is as follows:
as shown in fig. 6, during detection, polarized light emitted from the linear laser emitter 6 enters the magneto-optical rotation membrane 7 at a certain incident angle, an induced magnetic field containing defect information of the weld 10 is added in the magneto-optical rotation membrane 7, and when the polarized light passes through the magneto-optical rotation membrane 7, the polarization direction changes due to faraday magneto-optical rotation effect, and the polarized light contains defect information of the weld 10. Polarized light reflected from the magneto-optical rotation film 7 passes through the analyzer 8 and then is collected by the CCD camera 9, the CCD camera 9 forms light bar images, and the magneto-optical sensor transmits the light bar images to a computer in real time for processing and displaying.
As shown in fig. 7, the polarized light emitted from the laser emitter 6 enters the magneto-optical rotation film 7 at an α incident angle, an induced magnetic field is present in the magneto-optical rotation film 7 and is transmitted by the weldments, the polarized light undergoes N reflections inside the magneto-optical rotation film 7, and the path is (N +1) × h/cos α, and the rotation angle of the polarized light is obtained according to the faraday magneto-optical rotation effect:
θ＝(N+1)V×B×h/cosα
obviously, when the thickness h and the magnetic induction B of the magneto-optical rotation film 7 are not changed, the rotation angle of the polarized light is positively correlated with the number of reflections of the polarized light. The embodiment increases the Faraday rotation angle and improves the detection precision and the resolution of the magneto-optical sensor by increasing the reflection times of the polarized light in the magneto-optical film 7 without increasing the thickness h of the magneto-optical film.
Meanwhile, in the present embodiment, the line laser emitter 6 is used as a light source, and a laser light stripe emitted from the line laser emitter 6 irradiates a weld at a certain incident angle, and is reflected by the magneto-optical rotation membrane 7 and then emitted to the CCD camera 9 along a light path different from the incident light. The line light source is adopted to replace the surface light source in the existing magneto-optical imaging detection method, the passing routes of incident light and emergent light of the line light source are different, mutual interference cannot occur, and the problem that the existing magneto-optical image quality is not high is solved. The length of a line light bar emitted by the line light source is larger than the width of the welding line, the line light source can realize the detection of the whole welding line only by one-dimensional scanning, and the problem that two-dimensional scanning is needed due to the small irradiation area of the light source is effectively solved. In addition, because a light splitter is not needed, the light intensity attenuation caused in the light splitting process is reduced, and the imaging quality is greatly improved.
Example three:
in the present embodiment, a weld seam detection device is provided, as shown in fig. 8, which includes a magnetic field generator 14, a linear motion device, a computer 17, a main control board 15, and the magneto-optical sensor 11 described in the second embodiment, in order to implement full coverage of weld seam detection in the length direction, the magneto-optical sensor 11 and the detected weld seam move relatively, and the linear motion device is provided in the present embodiment, so that the weldment 12 moves relative to the magneto-optical sensor 11.
The magneto-optical sensor 11 is arranged above the linear motion device, and the magneto-optical sensor 11 is connected with the computer 17 through a wire. In this embodiment, the linear motion device includes a motion platform 13, a support, a lead screw and a motor 16, the lead screw horizontally penetrates through the support, and two ends of the lead screw are respectively connected with the support in a rotating manner.
One end of the screw rod is connected with the motor 16, and the screw rod is driven to rotate by the motor 16; the motor 16 is connected with a computer 17 through a main control board 15. The motion platform 13 is in threaded connection with the lead screw, and the motion platform 13 moves along the length direction of the lead screw when the lead screw rotates. It will be appreciated that other mechanical arrangements, such as a slider-and-slide mechanism, may be used for the linear motion device. The magnetic field generator 14 is fixed above the moving platform 13, when in use, the weldment 12 is placed above the magnetic field generator 14, and the moving platform 13 drives the magnetic field generator 14 and the weldment 12 to move together.
Example four:
in the embodiment, by using the weld seam detection device described in the third embodiment, during detection, the alternating excitation is performed on the weldment 12 by the alternating current-containing magnetic field generator 14, so that a magnetic field is induced on the weldment 12, and due to the existence of weld seam defects, the magnetic domain distribution and the strength of the positions with and without the defects are different. The magneto-optical sensor 11 emits polarized light to the excited welding seam and reflects the polarized light, and the CCD camera 9 collects light bar images containing welding seam defect information and transmits the light bar images to the computer 17 for storage and processing.
In order to scan the whole welding seam, the computer 17 controls the motor 16 to drive the moving platform 13 to move at a constant speed through the main control board 15, the moving platform 13 drags the weldment 12, the welding seam passes below the magneto-optical sensor 11 at a constant speed, and the magneto-optical sensor 11 collects light strip images of different parts of the welding seam. The magneto-optical sensor 11 transmits the collected light bar images to the computer 17, and the computer 17 performs splicing processing on the light bar images to obtain complete weld joint images. For best detection, the distance between the magneto-optical rotatory film 7 of the magneto-optical sensor 11 and the surface of the weldment 12 is as small as possible.
Because the magneto-optical sensor 11 of the embodiment adopts a line light source, the CCD camera 9 collects light bar images, and the width size of the light bar images is small, so that the welding seam defect information cannot be directly displayed. Therefore, the light bar image needs to be transmitted to the computer 17 for image stitching processing, and the following formula is adopted for image stitching:
in the formula: i' is a gray value matrix of the spliced weld image; i isijA matrix of gray values for the light bar image; deltaijThe gray value matrix of the area is 0, and the gray value matrix of the light bar image and the gray value matrix of the area between the light bars adopt the same column number j; n is the number of light bar images that need to be stitched.
The complete welding seam image is obtained by the image splicing method, and the image splicing method can be used for identifying the welding defects by human eyes, and can also be used for designing an image processing algorithm and automatically classifying and identifying the welding defects by a computer.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (7)
1. A weld detecting apparatus, comprising:
the magneto-optical sensor comprises a shell, and a line laser transmitter, an analyzer, a CCD camera and a magneto-optical rotation diaphragm which are arranged in the shell, wherein the line laser transmitter is positioned on one side above the magneto-optical rotation diaphragm, and the analyzer is positioned on the other side above the magneto-optical rotation diaphragm; the CCD camera and the analyzer are arranged coaxially;
the magneto-optical rotation membrane comprises a magneto-optical rotation medium layer, wherein a first reflecting layer is arranged on one side of the magneto-optical rotation medium layer, and a second reflecting layer is fixed on the other side of the magneto-optical rotation medium layer; the second reflecting layer is matched with the first reflecting layer to increase the reflection times of the polarized light; the width of the second reflecting layer is equal to that of the magnetic rotation medium layer, and the width of the first reflecting layer is smaller than that of the magnetic rotation medium layer;
the magneto-optical sensor is arranged above the linear motion device and is connected with a computer; the magnetic field generator is positioned below the magneto-optical sensor and can move along with the linear motion device;
the device adopts a line laser transmitter as a light source, a laser light bar emitted by the line laser transmitter irradiates a welding line at a certain incident angle, and is reflected by a magneto-optical rotation membrane and then emitted into a CCD camera along a light path different from the incident light; the length of a laser light bar emitted by the line laser emitter is greater than the width of a welding seam; the linear motion device enables the linear laser transmitter and the detected welding seam to move relatively.
2. The weld detecting device according to claim 1, wherein the first reflective layer is provided with a protective layer on a side thereof away from the magneto-optically active medium layer.
3. The weld detecting device according to claim 2, wherein the first reflective layer and the second reflective layer have the same thickness, and the protective layer has a thickness smaller than that of the second reflective layer.
4. The weld detecting device according to claim 1, wherein the line laser emitter and the CCD camera are respectively rotatably connected with the inner wall of the housing.
5. The welding seam detection device according to claim 1, wherein the linear motion device comprises a motion platform for placing a welding part, and the motion platform is connected with a motor through a lead screw; the magnetic field generator is fixed above the motion platform.
6. The welding seam detection device according to claim 5, wherein the motor and the computer are respectively connected with a main control board.
7. A welding seam detection method is characterized in that the welding seam detection device according to claim 6 is adopted, when in detection, an alternating current magnetic field generator is used for carrying out alternating excitation on a welding piece, and a magneto-optical sensor transmits polarized light to a welding seam in the excited welding piece and reflects the polarized light;
the CCD camera collects light strip images containing weld defect information and transmits the light strip images to the computer, the computer controls the motor to drive the moving platform to move at a constant speed through the main control board, the moving platform drags a weldment to enable the weld to pass below the magneto-optical sensor at a constant speed, and the magneto-optical sensor collects light strip images of different parts of the weld;
the magneto-optical sensor transmits the collected light bar image to the computer, and the computer processes the light bar image to obtain a complete weld image.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101487932A (en) * | 2009-02-23 | 2009-07-22 | 南京邮电大学 | Magneto-optic rotation reinforced device |
| CN104764798A (en) * | 2015-03-26 | 2015-07-08 | 电子科技大学 | Visual magnetic flux leakage detection device |
| CN106093182A (en) * | 2016-05-31 | 2016-11-09 | 电子科技大学 | A kind of visualization Magnetic Flux Leakage Inspecting modeling method based on circular current |
| CN107378200A (en) * | 2017-05-26 | 2017-11-24 | 广东工业大学 | Microgap welding seam tracking method and device under rotating excitation field excitation |
| CN108526745A (en) * | 2018-06-27 | 2018-09-14 | 苏州瑞耀三维科技有限公司 | A kind of laser welded seam detection device based on magneto-optical sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101487932A (en) * | 2009-02-23 | 2009-07-22 | 南京邮电大学 | Magneto-optic rotation reinforced device |
| CN104764798A (en) * | 2015-03-26 | 2015-07-08 | 电子科技大学 | Visual magnetic flux leakage detection device |
| CN106093182A (en) * | 2016-05-31 | 2016-11-09 | 电子科技大学 | A kind of visualization Magnetic Flux Leakage Inspecting modeling method based on circular current |
| CN107378200A (en) * | 2017-05-26 | 2017-11-24 | 广东工业大学 | Microgap welding seam tracking method and device under rotating excitation field excitation |
| CN108526745A (en) * | 2018-06-27 | 2018-09-14 | 苏州瑞耀三维科技有限公司 | A kind of laser welded seam detection device based on magneto-optical sensor |
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