CN110849884A - Method and system for detecting bonding defects inside composite insulator - Google Patents
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Abstract
The invention discloses a method and a system for detecting bonding defects inside a composite insulator. The invention realizes the rapid, accurate, non-contact and visual detection of the bonding defect inside the composite insulator, has good detection effect on the tiny bonding defect inside the composite insulator, and realizes the purpose of efficiently and accurately detecting the bonding defect inside the composite insulator.
Description
Technical Field
The invention relates to the technical field of power equipment detection, in particular to a method and a system for detecting bonding defects inside a composite insulator.
Background
Under a complex operation environment, the development of internal defects may cause abnormal heating and insulation failure of the composite insulator, and in a severe case, accidents such as breakdown, string falling, fracture and the like of the composite insulator can be caused, thereby causing great threat to the safe and stable operation of the power system. The internal bonding defect of the composite insulator is used as a main reason for inducing accidents such as abnormal heating and breakage of the insulator, and the detection of the internal bonding defect has great significance for reducing the failure occurrence rate of the composite insulator.
At present, two methods are mainly used for detecting the bonding defect inside the composite insulator. The first method is an anatomical classification method, in which the bonding condition inside the composite insulator is classified and judged by the anatomical classification method, and the classification judgment provided is discrete. The second is ultrasonic testing method, sends the ultrasonic wave through the ultrasonic flaw detector and detects the inside bonding condition of composite insulator, and ultrasonic testing method has advantages such as sensitivity is high, the penetrability is strong, detection speed is fast, nevertheless because ultrasonic testing need scribble the couplant, has certain requirement to measurement personnel's operation level, and the smearing of couplant also can cause certain influence to composite insulator outer insulation surface.
Although the detection method for the bonding defects inside the composite insulator has great limitation, the existing method can be used for detecting the bonding defects inside the composite insulator, the detection methods have certain damage to the composite insulator through the dissection and classification of the composite insulator or the application of a coupling agent on the surface of the composite insulator, and through the operation level and experience of detection personnel, the influence of subjective factors is great, and the provided detection result is easy to have the problems of wrong detection and omission.
Disclosure of Invention
The invention provides a method and a system for detecting bonding defects inside a composite insulator, which can realize quick, accurate, non-contact and visual detection of the bonding defects inside the composite insulator, and have good detection effect on tiny bonding defects inside the composite insulator.
In order to achieve the purpose, the embodiment of the invention adopts the following technical scheme:
in a first aspect, a method for detecting bonding defects inside a composite insulator is provided, which includes:
acquiring a visible light image and a first speckle image of a detected composite insulator, wherein the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
heating the detected composite insulator according to a thermal excitation light source;
acquiring a second speckle image of the detected composite insulator, wherein the second speckle image is an image of the detected composite insulator which is subjected to thermal excitation loading and then uniformly irradiated by a laser beam;
performing operation processing on the first speckle image and the second speckle image to obtain an interference fringe image and a phase image;
performing Gaussian filtering processing on the interference fringe image and the phase image;
performing edge detection on the interference fringe image and the phase image after the Gaussian filtering processing, and drawing an edge image;
fusing the edge image and the visible light image to obtain a fused image;
and identifying the internal defects of the composite insulator according to the fused image.
Optionally, the first speckle image and the second speckle image are displaced speckle interference images.
Optionally, the obtaining the interference fringe pattern by performing operation processing on the first speckle image and the second speckle image includes: and subtracting the first speckle image and the second speckle image to obtain an interference fringe image.
Optionally, the obtaining a phase map by performing operation processing on the first speckle image and the second speckle image includes: and obtaining a phase image by using the first speckle image and the second speckle image through a phase shift technology.
Optionally, performing gaussian filtering processing on the interference fringe image and the phase image; in the image after the Gaussian filtering treatment, the gray value of each point is changed into:
where (m, n) is the point coordinates of the image, σ is the standard deviation, and the gradation value is f (m, n).
Optionally, performing edge detection on the interference fringe pattern and the phase pattern after the gaussian filtering processing, and drawing an edge image, including:
the edge detection is to multiply the interference fringe pattern and the phase pattern point after the Gaussian filtering treatment by a sobel operator to obtain a non-interference fringe pattern and a phase pattern pointEquidirectional gradient value gx(m, n) and gy(m, n), and calculating a local gradient value G (m, n) and a gradient direction θ using the following formulas:
and judging the edge according to the set detection double-threshold maxVal and minVal, if the gradient is greater than maxVal, keeping the original value, if the gradient is less than minVal, setting the gradient to be 0, judging the edge if the intermediate point pixel is connected with the edge point, otherwise, setting the gradient to be 0, perfecting the edge in the image according to the double-threshold setting, and outputting an edge image.
In a second aspect, a system for detecting bonding defects inside a composite insulator is provided, comprising:
the laser array equipment is used for generating laser beams which are expanded and projected to the surface of the detected composite insulator through the lens;
the imaging device is used for acquiring a visible light image and a first speckle image of the detected composite insulator, wherein the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
the thermal excitation light source equipment is used for heating the detected composite insulator;
the imaging device is further used for acquiring a second speckle image of the detected composite insulator, wherein the second speckle image is an image of the detected composite insulator which is subjected to thermal excitation loading and then uniformly irradiated by a laser beam;
a data processing device for image acquisition, processing and storage;
the data processing device is further configured to perform operation processing on the first speckle image and the second speckle image acquired by the imaging device to obtain an interference fringe pattern and a phase pattern;
the data processing equipment is also used for carrying out Gaussian filtering processing on the interference fringe pattern and the phase pattern;
the data processing equipment is also used for carrying out edge detection on the interference fringe image and the phase image after the Gaussian filtering processing and drawing an edge image;
and the data processing equipment is also used for fusing the edge image and the visible light image acquired by the imaging equipment to obtain a fused image and identifying the internal defects of the composite insulator.
Optionally, the imaging apparatus includes a high-precision CCD camera and a misalignment device:
the high-precision CCD camera meets the detection maximum error tolerance value of the bonding defect of the composite insulator, and the number of pixels of a speckle image is higher than 1024 multiplied by 1024;
the dislocation device is used for controlling the dislocation amount of the laser beam and realizing the generation of dislocation images with set angles and distances.
Optionally, the system for detecting the bonding defect inside the composite insulator further includes a triggering device:
and the triggering equipment realizes the starting triggering of the imaging equipment, the laser array equipment and the thermal excitation light source equipment according to the data processing equipment.
Optionally, the thermally-activated light source device comprises a halogen focus lamp:
the halogen focusing lamp is heated for a preset time, the heating power reaches above a preset value, and parallel light beams are emitted according to the light condensation effect of the lamp barrel to uniformly heat a large area of a detected composite insulator.
The embodiment of the invention provides a method and a system for detecting bonding defects inside a composite insulator. The invention realizes the rapid, accurate, non-contact and visual detection of the bonding defect inside the composite insulator, has good detection effect on the tiny bonding defect inside the composite insulator, and realizes the purpose of efficiently and accurately detecting the bonding defect inside the composite insulator.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a method for detecting an internal bonding defect of a composite insulator according to an embodiment of the present invention;
fig. 2 is an image operation explanatory diagram in a method for detecting an internal bonding defect of a composite insulator according to an embodiment of the present invention;
FIG. 3 is a structural diagram of another system for detecting bonding defects inside a composite insulator according to a second embodiment of the present invention
Fig. 4 is a schematic diagram of a system for detecting an internal bonding defect of a composite insulator according to a third embodiment of the present invention.
Wherein: 201-laser array device; 202-an imaging device; 2021-malposition device; 2022-CCD camera; 203-a thermally actuated light source device; 204-a data processing device; 205-a trigger device; 206-detected composite insulator; 207-detecting the deformation caused by the bonding defect inside the composite insulator after heating.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention is described in further detail below with reference to the accompanying drawings:
example one
The embodiment of the invention provides a method for detecting bonding defects inside a composite insulator, which is used in the technical field of power equipment detection and comprises the following steps:
101. acquiring a visible light image and a first speckle image of a detected composite insulator, wherein the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
specifically, the visible light image is a clear image shot by the detected composite insulator under normal illumination;
the first speckle image is a staggered speckle interference image, laser beams are uniformly irradiated on the surface of the detected composite insulator, a single beam subjected to diffuse reflection is staggered and divided into two beams with the same amplitude, two mutually staggered speckle images are formed, and then the two beams are mutually interfered to form the staggered speckle interference image.
102. Heating the detected composite insulator according to a thermal excitation light source;
specifically, the composite insulator to be tested is uniformly heated over a large area for 0 to 10 minutes, and a small deformation is generated at the defect position after heating.
103. Acquiring a second speckle image of the detected composite insulator, wherein the second speckle image is an image of the detected composite insulator which is subjected to thermal excitation loading and then uniformly irradiated by a laser beam;
specifically, the second speckle image is a staggered speckle interference image, the laser beam is uniformly irradiated on the surface of the detected composite insulator, the single beam subjected to diffuse reflection is staggered and divided into two beams with the same amplitude, two mutually staggered speckle images are formed, and then the two beams are mutually interfered to form the staggered speckle interference image.
104. Performing operation processing on the first speckle image and the second speckle image to obtain an interference fringe image and a phase image;
specifically, the first speckle image and the second speckle image are subtracted to obtain an interference fringe pattern.
The speckle field I of the first speckle image can be represented as follows:
in the formula: i is0Is an object image (direct current component); gamma is the modulation amplitude;
is a random phase angle. Illustrating modulation of the object image into a random speckle field;
when the detected composite insulator is deformed by external force or heating, the optical path difference between the two interference points to the imaging surface changes, so that the phase difference between the two points becomesDelta is the relative phase change of the two points before and after deformation,the relative displacement information of two points caused by deformation is characterized. The speckle field I' of the second speckle image can be represented as
In the formula: delta is the relative phase change of the two points before and after deformation,
is a random phase angle;
carrying out subtraction operation on the speckle fields of the first speckle image and the second speckle image before and after deformation to obtain an expression IdRepresents the subtracted speckle field:
the resulting fringe pattern after subtraction characterizes the distribution of the relative phase changes.
Specifically, as shown in fig. 2, a phase shift technique is applied to the first speckle image and the second speckle image to obtain a phase map.
When Δ ═ 2n pi (n is an integer), dark streaks appear; when Δ is (2n +1) pi, bright fringes appear, the order of the fringes reflects the magnitude of the relative displacement before and after the deformation of the interference point, and the larger the relative displacement due to the defect, the more obvious the fringe pattern.
Interference points P and Q are formed by the reflected light beams of a certain point of the detected composite insulator under visible light, after the composite insulator is heated and deformed, the interference points P (x, y, z) and Q (x + delta x, y, z) respectively generate displacements (u, v, w) and (u + delta u, v + delta v, w + delta w), the optical path difference and the phase difference between the two points and an imaging surface are changed along with the displacements, new interference points P '(x + u, y + v, z + w) and Q' (x + delta x + u + delta u, y + v + delta v, z + w + delta w) are formed, and the relation between the relative phase change delta and the relative displacement (delta u, delta v, delta w) of the two points is as follows:
in the formula: λ isA laser wavelength; coefficient A, B, C and light source point S (x)s,ys,zs) And an imaging point O (x)o,yo,zo) Is related to the location of (a):
in the formula:
in the detection, the offset δ x is determined by the offset device, and when δ x is sufficiently small, the relative phase change can be regarded as a function of the partial derivative of the relative displacement in the offset direction, i.e.:
the fringe pattern generated by the dislocation speckle interference detection can display the internal defects of the detected object, the sensitivity for measuring the displacement variation is usually in the optical wavelength level, however, the relative phase variation of the integral multiple can only be determined approximately according to the identification fringe level, and accurate quantitative analysis cannot be carried out. In order to obtain an accurate relative phase change distribution diagram, a phase shift technology is introduced into the dislocation speckle interference detection;
optionally, among the numerous phase calculation methods, the 4-image phase shift method is the simplest and most convenient, and only by introducing the optical path difference of the interference point into the optical path changes of pi/2, pi and 3 pi/2 respectively and recording 3 new speckle images, the following equation set can be obtained, I1、I2、I3And I4The light intensities of the 1 st to 4 th images are respectively represented:
solving the system of equations to obtain
Likewise, the phase distribution after deformation can be solved as follows:
and simultaneously solving the phase distribution before and after deformation to obtain the relative phase change distribution before and after deformation. It should be noted that, here, the relative phase distribution Δ calculated by arctangent is a wrapped phase with a value range limited to (-pi, pi), and the actual phase distribution needs to be obtained through a unpacking operation.
105. Performing Gaussian filtering processing on the interference fringe image and the phase image;
specifically, the interference fringe pattern and the phase pattern are subjected to gaussian filtering, and the gray value of each point of the image after the gaussian filtering is changed into:
where (m, n) is the point coordinates of the image, σ is the standard deviation, and the gradation value is f (m, n).
106. Performing edge detection on the interference fringe image and the phase image after the Gaussian filtering processing, and drawing an edge image;
specifically, the edge detection is to multiply the interference fringe pattern and the phase pattern point after the gaussian filtering processing by a sobel operator to obtain gradient values g in different directionsx(m, n) and gy(m, n), and calculating a local gradient value G (m, n) and a gradient direction θ using the following formulas:
and judging the edge according to the set detection double-threshold maxVal and minVal, if the gradient is greater than maxVal, keeping the original value, if the gradient is less than minVal, setting the gradient to be 0, judging the edge if the intermediate point pixel is connected with the edge point, otherwise, setting the gradient to be 0, perfecting the edge in the image according to the double-threshold setting, and outputting an edge image.
And 105 and 106, processing the obtained interference fringe pattern and phase pattern by adopting an edge detection method, and better displaying the defect outline of the detected composite insulator. Compared with the traditional method such as laser speckle interference, the method can better present the defect outline information, can weaken or eliminate the influence of noise on the detection effect, and has stronger robustness in detection.
107. Fusing the edge image and the visible light image to obtain a fused image;
specifically, the edge image and the visible light image are subjected to image fusion, and a laplacian pyramid fusion method is adopted. And producing a Laplace pyramid according to image pixels, fusing each layer of images of the Laplace pyramid respectively based on a fusion rule with a larger selected pixel, and generating a fused image by adopting a reconstruction method after each layer of fused images are generated.
In step 107, the method for image fusion of the edge image and the visible light image enables the generated fusion image to better present the outline information of the defect and reflect the position information of the defect in the composite insulator, and has a great guiding effect on judging the damage degree of the defect.
108. And identifying the internal defects of the composite insulator according to the fused image.
Specifically, the fused image can not only show the defect information of the composite insulator, but also reflect the position information of the defect of the composite insulator.
The embodiment of the invention provides a method for detecting bonding defects inside a composite insulator, which comprises the steps of obtaining a visible light image, a first speckle image and a second speckle image of a detected composite insulator, carrying out operation processing on the first speckle image and the second speckle image to obtain an interference fringe image and a phase image, then carrying out Gaussian filtering processing, drawing an edge image, fusing the edge image with the visible light image to obtain a fused image, and identifying the internal defects of the composite insulator. The invention realizes the rapid, accurate, non-contact and visual detection of the bonding defect inside the composite insulator, has good detection effect on the tiny bonding defect inside the composite insulator, and realizes the purpose of efficiently and accurately detecting the bonding defect inside the composite insulator.
Example two
The embodiment of the present invention provides a system for detecting internal bonding defects of a composite insulator, which is used in the technical field of power equipment detection, and in particular can be used in combination with a method for detecting internal bonding defects of a composite insulator provided by the embodiment of the present invention, and as described with reference to fig. 3, the system for detecting internal bonding defects of a composite insulator may include the following structures:
a laser array device 201 for generating laser beams, which are expanded by a lens and projected to the surface of the detected composite insulator;
specifically, the emitted light from the surface of the insulator interferes with the reference beam projected directly by the laser array device 201, thereby creating a speckle field on the illuminated surface of the composite insulator. The laser can control the position of the generated laser beam in the horizontal and vertical directions, and meanwhile, a proper filtering device is adopted, so that the emitted light beam can be uniformly irradiated to the surface of the tested composite insulator.
The imaging device 202 is configured to acquire a visible light image and a first speckle image of the detected composite insulator, where the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
specifically, the imaging apparatus 202 includes a misalignment device 2021 and a high-precision CCD camera 2022;
the dislocation device 2021 is used for controlling the dislocation amount of the laser beam and realizing the generation of a dislocation image with a set angle and distance;
the focal length of the high-precision CCD camera 2022 is adjusted, the high-precision CCD camera 2022 is ensured to acquire clear images, the maximum error tolerance value of the detection of the bonding defects of the composite insulator is met, and the number of the pixels of the speckle images is higher than 1024 multiplied by 1024.
A thermal excitation light source device 203 for heating the detected composite insulator;
specifically, the thermal excitation light source apparatus 203 includes a halogen focus lamp: the halogen focusing lamp is heated for 0-10 minutes, the heating power reaches more than 1kW, and parallel light beams are emitted according to the light condensation effect of the lamp cylinder, so that the large-area uniform heating of the detected composite insulator is realized.
The imaging device 202 is further configured to acquire a second speckle image of the detected composite insulator, where the second speckle image is an image of the detected composite insulator after thermal excitation loading and under uniform irradiation of the laser beam.
A data processing device 204 for implementing speckle image acquisition, processing and storage;
specifically, software is arranged in the data processing module, continuous acquisition of detection images can be achieved through an operation function, the detection images are processed, the module has a splicing function, local partition images can be spliced, and therefore image display of the whole detection test piece is achieved.
The data processing device 204 is further configured to perform operation processing on the first speckle image and the second speckle image acquired by the imaging device 202 to obtain an interference fringe pattern and a phase pattern.
The data processing device 204 is further configured to perform gaussian filtering processing on the interference fringe pattern and the phase pattern.
The data processing device 204 is further configured to perform edge detection on the interference fringe pattern and the phase pattern after the gaussian filtering processing, and draw an edge image.
The data processing device 204 is further configured to fuse the edge image and the visible light image acquired by the imaging device 202 to obtain a fused image, and identify an internal defect of the composite insulator.
The system for detecting the bonding defect inside the composite insulator further comprises a trigger device 205: the triggering device 205 implements activation triggering of the imaging device 202, the laser array device, and the thermal excitation light source device 203 according to the data processing device 204.
The embodiment of the invention provides a detection system for bonding defects in a composite insulator, which is characterized in that a laser array device, a thermal excitation light source device and an imaging device are used for acquiring a visible light image, a first speckle image and a second speckle image of the detected composite insulator, a data processing device is used for carrying out operation processing on the first speckle image and the second speckle image to obtain an interference fringe image and a phase image, Gaussian filtering processing is carried out, an edge image is drawn to be fused with the visible light image to obtain a fused image, and the internal defects of the composite insulator are identified. The invention realizes the rapid, accurate, non-contact and visual detection of the bonding defect inside the composite insulator, has good detection effect on the tiny bonding defect inside the composite insulator, and realizes the purpose of efficiently and accurately detecting the bonding defect inside the composite insulator.
EXAMPLE III
The embodiment of the invention provides a detection system for internal bonding defects of a composite insulator, which is used in the technical field of power equipment detection, and particularly can realize detection and imaging of the internal bonding defects of the composite insulator by combining a schematic diagram of the detection system for the internal bonding defects of the composite insulator provided by figure 4.
The laser array device 201 is used for generating laser beams which are expanded and projected to the surface of the detected composite insulator 206 through a lens;
specifically, the emitted light from the surface of the insulator interferes with the reference beam projected directly by the laser array device 201, thereby creating a speckle field on the illuminated surface of the composite insulator. The laser can control the position of the generated laser beam in the horizontal and vertical directions, and meanwhile, a proper filtering device is adopted, so that the emitted light beam can be uniformly irradiated to the surface of the tested composite insulator.
The imaging device 202 is configured to acquire a visible light image and a first speckle image of the detected composite insulator 206, where the first speckle image is an image of the detected composite insulator 206 under uniform irradiation of a laser beam;
specifically, the imaging apparatus 202 includes a misalignment device 2021 and a high-precision CCD camera 2022;
the dislocation device 2021 is used for controlling the dislocation amount of the laser beam and realizing the generation of a dislocation image with a set angle and distance;
the focal length of the high-precision CCD camera 2022 is adjusted, the high-precision CCD camera 2022 is ensured to acquire clear images, the maximum error tolerance value of the detection of the bonding defects of the composite insulator is met, and the number of the pixels of the speckle images is higher than 1024 multiplied by 1024.
A thermal excitation light source device 203 for heating the detected composite insulator 206;
specifically, the thermal excitation light source apparatus 203 includes a halogen focus lamp: the halogen focusing lamp is heated for 0 to 10 minutes, the heating power reaches more than 1kW, and parallel light beams are emitted according to the light condensation effect of the lamp cylinder to uniformly heat a large area of the detected composite insulator 206;
the composite insulator 206 is tested for internal bond defects and undergoes deformation 207 upon heating.
The imaging device 202 is further configured to acquire a second speckle image of the detected composite insulator 206, where the second speckle image is an image of the detected composite insulator 206 after being thermally excited and loaded, which is generated by deformation 207 and is uniformly irradiated by the laser beam.
A data processing device 204 for implementing speckle image acquisition, processing and storage;
specifically, software is arranged in the data processing module, continuous acquisition of detection images can be achieved through an operation function, the detection images are processed, the module has a splicing function, local partition images can be spliced, and therefore image display of the whole detection test piece is achieved.
The data processing device 204 is further configured to perform operation processing on the first speckle image and the second speckle image acquired by the imaging device 202 to obtain an interference fringe pattern and a phase pattern.
The data processing device 204 is further configured to perform gaussian filtering processing on the interference fringe pattern and the phase pattern.
The data processing device 204 is further configured to perform edge detection on the interference fringe pattern and the phase pattern after the gaussian filtering processing, and draw an edge image.
And processing the obtained interference fringe pattern and phase pattern by adopting an edge detection method, and better displaying the defect outline of the detected composite insulator. Compared with the traditional method such as laser speckle interference, the method can better present the defect outline information, can weaken or eliminate the influence of noise on the detection effect, and has stronger robustness in detection.
The data processing device 204 is further configured to fuse the edge image and the visible light image acquired by the imaging device 202 to obtain a fused image, and identify an internal defect of the composite insulator.
The method for carrying out image fusion on the edge image and the visible light image enables the generated fusion image to show not only the outline information of the defect, but also the position information of the defect in the composite insulator, and has a great guiding effect on judging the damage degree of the defect.
The system for detecting the bonding defect inside the composite insulator further comprises a trigger device 205: the triggering device 205 implements activation triggering of the imaging device 202, the laser array device, and the thermal excitation light source device 203 according to the data processing device 204.
The embodiment of the invention provides a principle explanation of a detection system for bonding defects inside a composite insulator, which comprises the steps of obtaining a visible light image, a first speckle image and a second speckle image of the detected composite insulator through a laser array device, a thermal excitation light source device and an imaging device, carrying out operation processing on the first speckle image and the second speckle image through a data processing device to obtain an interference fringe image and a phase image, carrying out Gaussian filtering processing, drawing an edge image, fusing the edge image with the visible light image to obtain a fused image, and identifying the internal defects of the composite insulator. The invention realizes the rapid, accurate, non-contact and visual detection of the bonding defect inside the composite insulator, has good detection effect on the tiny bonding defect inside the composite insulator, and realizes the purpose of efficiently and accurately detecting the bonding defect inside the composite insulator.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (10)
1. A method for detecting bonding defects inside a composite insulator is characterized by comprising the following steps:
acquiring a visible light image and a first speckle image of a detected composite insulator, wherein the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
heating the detected composite insulator according to a thermal excitation light source;
acquiring a second speckle image of the detected composite insulator, wherein the second speckle image is an image of the detected composite insulator which is subjected to thermal excitation loading and then uniformly irradiated by a laser beam;
performing operation processing on the first speckle image and the second speckle image to obtain an interference fringe image and a phase image;
performing Gaussian filtering processing on the interference fringe image and the phase image;
performing edge detection on the interference fringe image and the phase image after the Gaussian filtering processing, and drawing an edge image;
fusing the edge image and the visible light image to obtain a fused image;
and identifying the internal defects of the composite insulator according to the fused image.
2. The method for detecting the bonding defect inside the composite insulator according to claim 1, wherein the first speckle image and the second speckle image are displaced speckle interference images.
3. The method for detecting the bonding defect inside the composite insulator according to claim 1, wherein the step of performing operation processing on the first speckle image and the second speckle image to obtain the interference fringe pattern comprises:
and subtracting the first speckle image and the second speckle image to obtain an interference fringe image.
4. The method for detecting the bonding defect inside the composite insulator according to claim 1, wherein the step of performing operation processing on the first speckle image and the second speckle image to obtain the phase diagram comprises the steps of:
and obtaining a phase image by using the first speckle image and the second speckle image through a phase shift technology.
5. The method for detecting the bonding defect inside the composite insulator according to claim 1, wherein the interference fringe pattern and the phase pattern are subjected to Gaussian filtering;
in the image after the Gaussian filtering treatment, the gray value of each point is changed into:
where (m, n) is the point coordinates of the image, σ is the standard deviation, and the gradation value is f (m, n).
6. The method for detecting the bonding defect inside the composite insulator according to claim 1, wherein the step of performing edge detection on the interference fringe pattern and the phase pattern after the gaussian filtering and drawing an edge image comprises the following steps:
the edge detection is to the interference fringe after the Gaussian filtering processingMultiplying the points of the graph and the phase graph by a sobel operator to obtain gradient values g in different directionsx(m, n) and gy(m, n), and calculating a local gradient value G (m, n) and a gradient direction θ using the following formulas:
and judging the edge according to the set detection double-threshold maxVal and minVal, if the gradient is greater than maxVal, keeping the original value, if the gradient is less than minVal, setting the gradient to be 0, judging the edge if the intermediate point pixel is connected with the edge point, otherwise, setting the gradient to be 0, perfecting the edge in the image according to the double-threshold setting, and outputting an edge image.
7. The utility model provides a detecting system of inside bonding defect of composite insulator which characterized in that includes:
the laser array equipment is used for generating laser beams which are expanded and projected to the surface of the detected composite insulator through the lens;
the imaging device is used for acquiring a visible light image and a first speckle image of the detected composite insulator, wherein the first speckle image is an image of the detected composite insulator under uniform irradiation of a laser beam;
the thermal excitation light source equipment is used for heating the detected composite insulator;
the imaging device is further used for acquiring a second speckle image of the detected composite insulator, wherein the second speckle image is an image of the detected composite insulator which is subjected to thermal excitation loading and then uniformly irradiated by a laser beam;
a data processing device for image acquisition, processing and storage;
the data processing device is further configured to perform operation processing on the first speckle image and the second speckle image acquired by the imaging device to obtain an interference fringe pattern and a phase pattern;
the data processing equipment is also used for carrying out Gaussian filtering processing on the interference fringe pattern and the phase pattern;
the data processing equipment is also used for carrying out edge detection on the interference fringe image and the phase image after the Gaussian filtering processing and drawing an edge image;
and the data processing equipment is also used for fusing the edge image and the visible light image acquired by the imaging equipment to obtain a fused image and identifying the internal defects of the composite insulator.
8. The system for detecting the bonding defect inside the composite insulator according to claim 7, wherein the imaging device comprises a high-precision CCD camera and a dislocation device:
the high-precision CCD camera meets the detection maximum error tolerance value of the bonding defect of the composite insulator, and the number of pixels of a speckle image is higher than 1024 multiplied by 1024;
the dislocation device is used for controlling the dislocation amount of the laser beam and realizing the generation of dislocation images with set angles and distances.
9. The system for detecting bonding defects inside a composite insulator according to claim 7, further comprising a triggering device:
and the triggering equipment realizes the starting triggering of the imaging equipment, the laser array equipment and the thermal excitation light source equipment according to the data processing equipment.
10. The system for detecting bonding defects inside a composite insulator according to claim 7, wherein the thermally-activated light source device comprises a halogen focus lamp:
the halogen focusing lamp is heated for a preset time, the heating power reaches above a preset value, and parallel light beams are emitted according to the light condensation effect of the lamp barrel to uniformly heat a large area of a detected composite insulator.
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