Optical fiber coating concentricity identification device and method

Abstract

The present invention discloses a device and method for identifying the concentricity of optical fiber coating, which belongs to the field of optical fiber processing technology. The device includes an image acquisition unit, a diffraction dark fringe slit generating unit and a concentricity detection unit; the image acquisition unit uses a camera to acquire the diffraction fringe image of the optical fiber, and pre-processes the diffraction fringe image to obtain a standard diffraction fringe image; the diffraction dark fringe slit generating unit is used to identify the central bright spot, the first diffraction dark fringe slit and the second diffraction dark fringe of the standard diffraction fringe image; the concentricity detection unit is used to determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe slit and the second diffraction dark fringe. The present invention can determine the diffraction dark fringe and the central bright spot by acquiring the diffraction fringe image, thereby judging whether the concentricity of the optical fiber is qualified and ensuring the quality of the optical fiber.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber processing, and in particular relates to an optical fiber coating concentricity identification device and method. Background Art

[0002] The optical fiber drawing production process is to put the optical fiber preform into a heating furnace to heat it and soften it, and then shrink and become thinner rapidly under the action of surface tension, and then cool it through a cooling device. When the micro cracks on the surface of the bare optical fiber have not yet expanded due to the influence of moisture in the air, it is necessary to quickly coat it to protect the surface of the optical fiber. In the coating system, the surface of the optical fiber is coated with resin coating, and then enters the curing system. After curing and molding, the tensile and bending resistance of the bare optical fiber is strengthened, and finally the optical fiber is collected by the take-up winding device. The purpose of coating the resin layer on the surface of the optical fiber is to protect the bare optical fiber from contact with external dust particles. These particles will significantly reduce the strength of the optical fiber. The coating can also prevent external moisture from corroding the optical fiber, avoid increased loss, and provide micro-bending protection for the optical fiber in various environments.

[0003] The existing optical fiber coating concentricity monitoring method usually uses a light source to illuminate the optical fiber. The light from the light source passes through the optical fiber to form diffraction light fringes on the receiver. The optical fiber coating concentricity is analyzed by observing the diffraction light fringes with the naked eye. However, due to different experiences of each person, manual observation will lead to different conclusions, resulting in measurement errors and unable to guarantee real-time performance. At the same time, manual observation can only be carried out at intervals, and real-time monitoring cannot be achieved, resulting in a large number of scrapped products. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a device and method for identifying the concentricity of optical fiber coating.

[0005] The technical solution of the present invention is: an optical fiber coating concentricity identification device comprises an image acquisition unit, a diffraction dark fringe slit generation unit and a concentricity detection unit;

[0006] The image acquisition unit uses a camera to acquire the diffraction fringe image of the optical fiber, and pre-processes the diffraction fringe image to obtain a standard diffraction fringe image;

[0007] The diffraction dark fringe slit generating unit is used to identify the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe slit and the second diffraction dark fringe;

[0008] The concentricity detection unit is used to determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe seam and the second diffraction dark fringe.

[0009] The beneficial effect of the present invention is that the optical fiber coating concentricity identification device can determine the diffraction dark fringes and the central bright spot by collecting the diffraction fringe image, thereby judging whether the concentricity of the optical fiber is qualified and ensuring the quality of the optical fiber.

[0010] Based on the above device, the present invention also proposes a method for identifying the concentricity of optical fiber coating, comprising the following steps:

[0011] S1. Using a camera to collect the diffraction fringe image of the optical fiber, and preprocessing the diffraction fringe image to obtain a standard diffraction fringe image;

[0012] S2, identifying the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe gap and the second diffraction dark fringe;

[0013] S3. Determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe seam and the second diffraction dark fringe.

[0014] Furthermore, in S1, a Gaussian filter is used to preprocess the diffraction fringe image, and the calculation formula is:

[0015] ;

[0016] In the formula, Indicates that the horizontal coordinate in the standard diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, represents the kernel size of the Gaussian filter, represents the length of the diffraction fringe image, represents the width of the diffraction fringe image, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel.

[0017] The beneficial effect of the above further solution is that in the present invention, a Gaussian filter is used in combination with the pixel values ​​of the pixel's neighborhood to filter the pixel, thereby reducing the impact of image noise and artifacts.

[0018] Furthermore, S2 includes the following sub-steps:

[0019] S21, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and determining the central bright spot;

[0020] S22, dividing the standard diffraction fringe image into a left partial image and a right partial image using the column of pixel points where the central bright spot is located;

[0021] S23, extracting the Laplacian matrix of the left partial image and the Laplacian matrix of the right partial image respectively;

[0022] S24, calculating the fusion value of the pixel points in the left local image according to the Laplacian matrix of the left local image; calculating the fusion value of the pixel points in the right local image according to the Laplacian matrix of the right local image;

[0023] S25, generating a fusion dependency value;

[0024] S26, generating a first diffraction dark fringe slit and a second diffraction dark fringe slit according to the fusion value of the pixel points in the left local image, the fusion value of the pixel points in the right local image, and the fusion dependency value.

[0025] The beneficial effect of the above further scheme is: in the present invention, the position of the central bright spot is determined according to the HSV component of the standard diffraction fringe image, and then the column where the central bright spot is located is used as the symmetry axis, and two diffraction dark fringe slits are determined in the images on both sides, and the distance is compared with the central bright spot. The above process can take into account the pixel changes of the standard diffraction fringe image and accurately locate the stripe slits.

[0026] Furthermore, S21 includes the following sub-steps:

[0027] S211, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and combining the hue component, saturation component, and color brightness component of the pixel point to form a three-dimensional space vector of the pixel point;

[0028] S212, performing a cross product operation on all three-dimensional space vectors to obtain a three-dimensional space product;

[0029] S213, obtaining a brightness threshold of the pixel point according to the hue component, saturation component, color brightness component and three-dimensional spatial product of each pixel point;

[0030] S214: Take the pixel point with the maximum brightness threshold as the central bright spot.

[0031] In S212, all three-dimensional space vector cross products are still in vector form after the operation. The calculation formula of the three-dimensional space product is: ; In the formula, Represents the three-dimensional space vector of the first pixel point, Represents the three-dimensional space vector of the second pixel point, Indicates The three-dimensional space vector of pixel points, Indicates The three-dimensional space vector of pixel points, Represents the number of pixels in the standard diffraction fringe image.

[0032] Furthermore, in S213, the brightness threshold of the pixel point The calculation formula is:

[0033] ;

[0034] In the formula, Represents the hue component of the pixel. Represents the saturation component of the pixel. Represents the color brightness component of the pixel. represents the three-dimensional spatial product, Indicates taking the maximum value, Represents the modulo operation on a vector.

[0035] Further, in S24, the fusion value of the pixel point in the left local image The calculation formula is:

[0036] ;

[0037] In the formula, represents the Laplacian matrix of the left local image, represents the pixel value of the pixel in the left local image, Represents the number of pixels in the left local image, represents logarithmic operation, represents the F-norm operation, Represents absolute value operation;

[0038] In S24, the fusion value of the pixel in the right local image The calculation formula is:

[0039] ;

[0040] Where W represents the Laplacian matrix of the right local image, represents the pixel value of the pixel in the right local image, Indicates the number of pixels in the right local image.

[0041] Furthermore, in S25, the fusion dependency value The calculation formula is:

[0042] ;

[0043] In the formula, Indicates rounding operation. represents the Laplacian matrix of the left local image, represents the Laplacian matrix of the right local image, represents the matrix transpose operation, Represents the rank operation of a matrix.

[0044] Further, in S26, the method for generating the first diffraction dark fringe seam is specifically as follows: taking the pixel points in the left local image whose fusion value is greater than the fusion dependence value as the first diffraction area, taking the column of the pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the first diffraction area as the second diffraction area, and taking the first diffraction area and the second diffraction area as the first diffraction dark fringe seam;

[0045] In S26, the method for generating the second diffraction dark fringe seam is specifically as follows: taking the pixel points in the right local image whose fusion value is greater than the fusion dependence value as the third diffraction area, taking the column of pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the third diffraction area as the fourth diffraction area, and taking the third diffraction area and the fourth diffraction area as the second diffraction dark fringe seam.

[0046] Furthermore, S3 includes the following sub-steps:

[0047] S31, calculating the distance between the midpoint of each fringe in the first diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters;

[0048] S32, calculating the distance between the midpoint of each fringe in the second diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters;

[0049] S33. If all the distance parameters corresponding to the first diffraction dark fringe slits are the same and all the distance parameters corresponding to the second diffraction dark fringe slits are the same, the concentricity of the optical fiber is qualified; otherwise, the concentricity of the optical fiber is unqualified.

[0050] The beneficial effect of the above further scheme is that in the present invention, by judging whether the distance between the midpoint of each stripe in the diffraction dark stripe slit and the central bright spot is the same, it is determined whether the diffraction stripes are symmetrically distributed around the central bright spot. If so, the concentricity of the optical fiber is good and the optical fiber is qualified, otherwise the optical fiber is unqualified. Of course, in practical applications, some differences in the distance parameters are allowed, and the tolerance of the difference size can be set manually.

[0051] The beneficial effects of the present invention are as follows: the present invention pre-processes the diffraction fringe image of the optical fiber to improve the recognition accuracy; accurately extracts two diffraction dark fringe slits and a central bright spot of the standard diffraction fringe image, and obtains the recognition result through the positional relationship between the two diffraction dark fringe slits and the central bright spot; the present invention utilizes the diffraction phenomenon and the image processing process to achieve high-precision measurement and recognition of the concentricity of the optical fiber without manual intervention, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a structural schematic diagram of an optical fiber coating concentricity identification device;

[0053] Figure 2 A flow chart of a method for identifying optical fiber coating concentricity;

[0054] Figure 3 A schematic diagram of the structure of a specific device for identifying the concentricity of optical fiber coating;

[0055] In the figure, 1. controller; 2. camera; 3. laser; 4. optical fiber; 5. reflector; 6. diffraction stripes; 7. first diffraction dark stripes; 8. central bright spot; 9. second diffraction dark stripes. DETAILED DESCRIPTION

[0056] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0057] like Figure 1 As shown, the present invention provides a device for identifying the concentricity of optical fiber coating, including an image acquisition unit, a diffraction dark fringe seam generation unit and a concentricity detection unit;

[0058] The image acquisition unit uses a camera to acquire the diffraction fringe image of the optical fiber, and pre-processes the diffraction fringe image to obtain a standard diffraction fringe image;

[0059] The diffraction dark fringe slit generating unit is used to identify the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe slit and the second diffraction dark fringe;

[0060] The concentricity detection unit is used to determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe seam and the second diffraction dark fringe.

[0061] Based on the above device, the present invention also proposes a method for identifying the concentricity of optical fiber coating, such as Figure 2 As shown, the following steps are included:

[0062] S1. Using a camera to collect the diffraction fringe image of the optical fiber, and preprocessing the diffraction fringe image to obtain a standard diffraction fringe image;

[0063] S2, identifying the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe gap and the second diffraction dark fringe;

[0064] S3. Determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe seam and the second diffraction dark fringe.

[0065] In the embodiment of the present invention, in S1, a Gaussian filter is used to pre-process the diffraction fringe image, and the calculation formula is:

[0066] ;

[0067] In the formula, Indicates that the horizontal coordinate in the standard diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, represents the kernel size of the Gaussian filter, represents the length of the diffraction fringe image, represents the width of the diffraction fringe image, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical coordinate is The pixel value of the pixel.

[0068] In the present invention, a Gaussian filter is used in combination with the neighborhood pixel values ​​of the pixel point to filter the pixel point, thereby reducing the impact of image noise and artifacts.

[0069] In this embodiment of the present invention, S2 includes the following sub-steps:

[0070] S21, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and determining the central bright spot;

[0071] S22, dividing the standard diffraction fringe image into a left partial image and a right partial image using the column of pixel points where the central bright spot is located;

[0072] S23, extracting the Laplacian matrix of the left partial image and the Laplacian matrix of the right partial image respectively;

[0073] S24, calculating the fusion value of the pixel points in the left local image according to the Laplacian matrix of the left local image; calculating the fusion value of the pixel points in the right local image according to the Laplacian matrix of the right local image;

[0074] S25, generating a fusion dependency value;

[0075] S26, generating a first diffraction dark fringe slit and a second diffraction dark fringe slit according to the fusion value of the pixel points in the left local image, the fusion value of the pixel points in the right local image, and the fusion dependency value.

[0076] In the present invention, the position of the central bright spot is determined according to the HSV component of the standard diffraction fringe image, and then the column where the central bright spot is located is used as the symmetry axis to determine two diffraction dark fringe slits in the two side images, and the distance is compared with the central bright spot. The above process can take into account the pixel changes of the standard diffraction fringe image and accurately locate the fringe slits. The Laplacian matrix of the local image is in the form of a square matrix, which is represented as a matrix of a graph.

[0077] In the embodiment of the present invention, S21 includes the following sub-steps:

[0078] S211, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and combining the hue component, saturation component, and color brightness component of the pixel point to form a three-dimensional space vector of the pixel point;

[0079] S212, performing a cross product operation on all three-dimensional space vectors to obtain a three-dimensional space product;

[0080] S213, obtaining a brightness threshold of the pixel point according to the hue component, saturation component, color brightness component and three-dimensional spatial product of each pixel point;

[0081] S214: Take the pixel point with the maximum brightness threshold as the central bright spot.

[0082] In S212, all three-dimensional space vector cross products are still in vector form after the operation. The calculation formula of the three-dimensional space product is: ; In the formula, Represents the three-dimensional space vector of the first pixel point, Represents the three-dimensional space vector of the second pixel point, Indicates The three-dimensional space vector of pixel points, Indicates The three-dimensional space vector of pixel points, Represents the number of pixels in the standard diffraction fringe image.

[0083] In the embodiment of the present invention, in S213, the brightness threshold of the pixel point The calculation formula is:

[0084] ;

[0085] In the formula, Represents the hue component of the pixel. Represents the saturation component of the pixel. Represents the color brightness component of the pixel. represents the three-dimensional spatial product, Indicates taking the maximum value, Represents the modulo operation on a vector.

[0086] In the embodiment of the present invention, in S24, the fusion value of the pixel point in the left local image The calculation formula is:

[0087] ;

[0088] In the formula, represents the Laplacian matrix of the left local image, represents the pixel value of the pixel in the left local image, Represents the number of pixels in the left local image, represents logarithmic operation, represents the F-norm operation;

[0089] In S24, the fusion value of the pixel in the right local image The calculation formula is:

[0090] ;

[0091] Where W represents the Laplacian matrix of the right local image, represents the pixel value of the pixel in the right local image, Indicates the number of pixels in the right local image.

[0092] In the embodiment of the present invention, in S25, the fusion dependency value The calculation formula is:

[0093] ;

[0094] In the formula, Indicates rounding operation. represents the Laplacian matrix of the left local image, represents the Laplacian matrix of the right local image, represents the matrix transpose operation, Represents the rank operation of a matrix.

[0095] In the embodiment of the present invention, in S26, the method for generating the first diffraction dark fringe seam is specifically as follows: taking the pixel points in the left local image whose fusion value is greater than the fusion dependence value as the first diffraction area, taking the column of the pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the first diffraction area as the second diffraction area, and taking the first diffraction area and the second diffraction area as the first diffraction dark fringe seam;

[0096] In S26, the method for generating the second diffraction dark fringe seam is specifically as follows: taking the pixel points in the right local image whose fusion value is greater than the fusion dependence value as the third diffraction area, taking the column of pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the third diffraction area as the fourth diffraction area, and taking the third diffraction area and the fourth diffraction area as the second diffraction dark fringe seam.

[0097] In this embodiment of the present invention, S3 includes the following sub-steps:

[0098] S31, calculating the distance between the midpoint of each fringe in the first diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters;

[0099] S32, calculating the distance between the midpoint of each fringe in the second diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters;

[0100] S33. If all the distance parameters corresponding to the first diffraction dark fringe slits are the same and all the distance parameters corresponding to the second diffraction dark fringe slits are the same, the concentricity of the optical fiber is qualified; otherwise, the concentricity of the optical fiber is unqualified.

[0101] In the present invention, by judging whether the midpoints of the diffraction dark fringe slits are at the same distance from the central bright spot, it is determined whether the diffraction fringes are symmetrically distributed around the central bright spot. If so, the concentricity of the optical fiber is good and the optical fiber is qualified. Otherwise, the optical fiber is unqualified. Of course, in practical applications, some differences in the distance parameters are allowed, and the tolerance of the difference can be set manually.

[0102] In the embodiment of the present invention, Figure 3 As shown, the present invention also provides a specific identification device, which uses an image recognition method to identify the diffraction stripes of the optical fiber, thereby automatically judging the concentricity of the system optical fiber coating. The laser 3 emits laser light to irradiate the optical fiber 4, and forms diffraction stripes 6 on the reflector 5. The camera 2 collects the diffraction stripe image on the reflector 5 and transmits it to the controller 1. The controller 1 calculates the distance from the first diffraction dark stripe 7 and the second diffraction dark stripe 9 to the central bright spot 8 by collecting the coating. It is thus judged whether the concentricity of the optical fiber is within the qualified range.

[0103] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for identifying the concentricity of optical fiber coating, characterized in that: The following steps are involved: S1. Using a camera to collect the diffraction fringe image of the optical fiber, and preprocessing the diffraction fringe image to obtain a standard diffraction fringe image; S2, identifying the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe slit, and the second diffraction dark fringe slit; S3, determining the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe slit and the second diffraction dark fringe slit; The S2 comprises the following sub-steps: S21, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and determining the central bright spot; S22, dividing the standard diffraction fringe image into a left partial image and a right partial image using the column of pixel points where the central bright spot is located; S23, extracting the Laplacian matrix of the left partial image and the Laplacian matrix of the right partial image respectively; S24, calculating the fusion value of the pixel points in the left local image according to the Laplacian matrix of the left local image; calculating the fusion value of the pixel points in the right local image according to the Laplacian matrix of the right local image; S25, generating a fusion dependency value; S26, generating a first diffraction dark fringe slit and a second diffraction dark fringe slit according to the fusion value of the pixel point in the left partial image, the fusion value of the pixel point in the right partial image, and the fusion dependency value; In S26, the method for generating the first diffraction dark fringe seam is specifically as follows: taking the pixel points in the left partial image whose fusion value is greater than the fusion dependence value as the first diffraction area, taking the column of the pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the first diffraction area as the second diffraction area, and taking the first diffraction area and the second diffraction area as the first diffraction dark fringe seam; In S26, the method for generating the second diffraction dark fringe seam is specifically as follows: taking the pixel points in the right local image whose fusion value is greater than the fusion dependence value as the third diffraction area, taking the column of pixel points where the central bright spot is located as the symmetry axis, taking the area symmetrical about the symmetry axis of the third diffraction area as the fourth diffraction area, and taking the third diffraction area and the fourth diffraction area as the second diffraction dark fringe seam.

2. The optical fiber coating concentricity identification method according to claim 1, characterized in that: In S1, the diffraction fringe image is preprocessed using a Gaussian filter, and the calculation formula is: ； In the formula, Indicates that the horizontal coordinate in the standard diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, represents the kernel size of the Gaussian filter, represents the length of the diffraction fringe image, represents the width of the diffraction fringe image, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel point, Indicates that the horizontal coordinate in the diffraction fringe image is And the vertical axis is The pixel value of the pixel.

3. The optical fiber coating concentricity identification method according to claim 1, characterized in that: The S21 comprises the following sub-steps: S211, converting the standard diffraction fringe image from the RGB color space to the HSV color space, and combining the hue component, saturation component, and color brightness component of the pixel point to form a three-dimensional space vector of the pixel point; S212, performing a cross product operation on all three-dimensional space vectors to obtain a three-dimensional space product; S213, obtaining a brightness threshold of the pixel point according to the hue component, saturation component, color brightness component and three-dimensional spatial product of each pixel point; S214: Take the pixel point with the maximum brightness threshold as the central bright spot.

4. The optical fiber coating concentricity identification method according to claim 3, characterized in that: In S213, the brightness threshold of the pixel point The calculation formula is: ； In the formula, Represents the hue component of the pixel. Represents the saturation component of the pixel. Represents the color brightness component of the pixel. represents the three-dimensional spatial product, Indicates taking the maximum value, Represents the modulo operation on a vector.

5. The optical fiber coating concentricity identification method according to claim 1, characterized in that: In S24, the fusion value of the pixel point in the left local image The calculation formula is: ； In the formula, represents the Laplacian matrix of the left local image, represents the pixel value of the pixel in the left local image, Represents the number of pixels in the left local image, represents logarithmic operation, represents the F-norm operation, Represents absolute value operation; In S24, the fusion value of the pixel point in the right local image The calculation formula is: ； In the formula, represents the Laplacian matrix of the right local image, represents the pixel value of the pixel in the right local image, Indicates the number of pixels in the right local image.

6. The optical fiber coating concentricity identification method according to claim 1, characterized in that: In S25, the fusion dependency value The calculation formula is: ； In the formula, Indicates rounding operation. represents the Laplacian matrix of the left local image, represents the Laplacian matrix of the right local image, represents the matrix transpose operation, Represents the rank operation of a matrix.

7. The optical fiber coating concentricity identification method according to claim 1, characterized in that: The S3 comprises the following sub-steps: S31, calculating the distance between the midpoint of each fringe in the first diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters; S32, calculating the distance between the midpoint of each fringe in the second diffraction dark fringe slit and the central bright spot to obtain a plurality of distance parameters; S33. If all the distance parameters corresponding to the first diffraction dark fringe slits are the same and all the distance parameters corresponding to the second diffraction dark fringe slits are the same, the concentricity of the optical fiber is qualified; otherwise, the concentricity of the optical fiber is unqualified.

8. An optical fiber coating concentricity identification device, characterized in that: The optical fiber coating concentricity identification device is used to perform the optical fiber coating concentricity identification method according to claim 1, and the optical fiber coating concentricity identification device includes an image acquisition unit, a diffraction dark fringe seam generation unit and a concentricity detection unit; The image acquisition unit uses a camera to acquire the diffraction fringe image of the optical fiber, and pre-processes the diffraction fringe image to obtain a standard diffraction fringe image; The diffraction dark fringe slit generating unit is used to identify the central bright spot of the standard diffraction fringe image, the first diffraction dark fringe slit and the second diffraction dark fringe slit; The concentricity detection unit is used to determine the concentricity of the optical fiber according to the central bright spot, the first diffraction dark fringe slit and the second diffraction dark fringe slit.

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