CN117863020A - Optical fiber end face detection method - Google Patents

Abstract

The invention mainly relates to the field of automatic detection, in particular to an optical fiber end face detection method, an optical fiber, a detection device and a detection device, wherein the optical fiber is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center; the optical fiber end face is an optical fiber end face after fusion treatment, and the edge of the optical fiber end face is provided with arc transition to the end face main body and a plurality of point light sources; in the axial direction, a plurality of point light sources are positioned in front of the end face of the optical fiber, and in the projection of the axial direction, a plurality of point light sources are positioned on a concentric circle of the circle center; the point light source can generate a light reflecting area at the edge of one side corresponding to the end face of the optical fiber; the point light sources sequentially emit light to obtain images of the end faces of the optical fibers when the point light sources emit light; detecting the light reflecting areas of the images in the end face of the optical fiber, obtaining the quantity information of the light reflecting areas, and judging that the end face of the optical fiber is unqualified if the quantity of the light reflecting areas in the end face of the optical fiber is detected to be more than or equal to two.

Description

Optical fiber end face detection method

Technical Field

The invention mainly relates to the field of automatic detection, in particular to an optical fiber end face detection method.

Background

The prior art is a patent with application number 201410713984.8 and name of optical fiber end face detection method and optical fiber end face polishing and detecting equipment, which discloses optical fiber end face polishing and detecting equipment, comprising a power supply device, a light source, a camera device, an image processing device, an image display device, a motor driving device, a discharging device and an optical fiber clamp device, wherein the power supply device is respectively connected with the light source, the camera device, the image processing device, the image display device, the motor driving device and the discharging device; the image processing device is connected with the image pick-up device, the image display device, the motor driving device and the discharging device; the discharge device consists of an electrode group, and the optical fiber clamp device is connected with the motor driving device; the optical fiber fixture device is provided with an optical fiber fixing groove, and the light source is opposite to the optical fiber fixing groove. The patent is a melting treatment device for the end face of an optical fiber, the end face of the optical fiber is melted by a discharge device, then the end face of the optical fiber is imaged by an imaging device, and the patent defines data to be collected for detecting the end face of the optical fiber, but the patent does not disclose a specific end face detection method.

The patent with the application number 201910430030.9, entitled optical fiber end face polishing detection device and method discloses an optical fiber end face polishing detection device, which performs discharge melting treatment on an optical fiber cut end face to ensure consistency of cleanliness, damage degree and end face curvature radius of the optical fiber end face, and after the discharge melting treatment is performed on the optical fiber end face, acquires an optical fiber end face image in real time, transmits the optical fiber end face image to a display screen for observation, and simultaneously transmits the optical fiber end face image to an image processing device for performing black-white binarization treatment to calculate the cleanliness, damage degree and curvature radius of the optical fiber end face, and automatically judges the heat melting condition of the optical fiber end face through the image processing device according to an optical reflection principle so as to determine whether to add discharge melting once to ensure that attachment on the optical fiber end face is cleaned, and the detection steps of repairing the cut damage and forming a proper curvature radius … … comprise: acquiring an image of the end face of the optical fiber, and performing foreground segmentation on the image acquired by the camera device by the image processing device to acquire the image of the end face of the optical fiber; the binarization processing step, transmitting the optical fiber end face image acquired by the image pickup device to the image device for black and white binarization processing; calculating the curvature radius of the optical fiber end face, comparing the curvature radius with the standard range parameter of the curvature radius of the preset optical fiber end face of the image processing device, and ending the operation if the comparison result accords with the predefined value; otherwise, adding a polishing step, repeating the steps of collecting the end face image of the optical fiber and binarizing treatment, and then recalculating and comparing until the curvature radius of the end face of the optical fiber is lower than a preset minimum value, and ending the operation; the radius of curvature conforming to the predefined means that the inner diameter of the formed bright ring is in the interval between the circle of the preset radius R1 and the circle of the preset radius R2. The patent discloses a general procedure for detection when a ring light source is used in a melt processing apparatus, but does not disclose a specific judgment method nor a method for detecting an end face flash.

The optical fiber is cut before it is processed through the above-described prior art fusion apparatus, and the optical fiber is usually completed by a cutter. The optical fiber cutter is as the patent with application number 20212085945. X, the name is an optical fiber cutter, which discloses an optical fiber cutter body, comprising an optical cable fixing part, an optical fiber fixing table, an inner cavity, a blade seat and a sliding rod; the optical cable fixing part is used for fixing the wire stripping optical cable and enabling optical fibers of the wire stripping optical cable to be configured on the optical fiber fixing table; the bottom of the optical fiber fixing table is provided with an inner cavity, the inner cavity is internally provided with the sliding rod, and the sliding rod is sleeved with a spring; the optical fiber cutting knife comprises a sliding rod, a cutter seat, a cover body, a breaking device, a cutting device and a cutting device, wherein the cutter seat is provided with the cutter, the cutter seat is slidingly arranged on the sliding rod, the cutter seat is provided with an extension arm, the spring is compressed when the cutter seat is close to one end of the sliding rod, and the cutter seat is clamped on a bayonet of the optical fiber cutting knife body through a clamping point of the extension arm, so that the cutter seat and the optical fiber cutting knife body are relatively fixed … …, and the cover body is further provided with the breaking device, wherein the breaking device comprises a breaking spring, an extension table and a breaking arm; during the closing process of the cover body, the extending table is abutted against the surface of the blade seat and compresses the breaking spring to enable the extending table and the breaking arm to be contracted, and when the blade seat is pushed to pop up and move to the other end of the sliding rod by the spring in a compressed state, the blade seat is separated from the extending table, and meanwhile the breaking arm stretches out to impact and break the optical fiber. The optical fiber cutting knife is a practical tool, and the working principle is that a knife edge is formed on an optical fiber through a blade, and then the optical fiber is broken through a breaking mode, wherein the breaking mode possibly causes a burr to be formed at the end of the optical fiber far away from the knife edge due to breaking force or unexpected factors when the optical fiber is broken, namely, a tearing-shaped bulge is formed at the edge of the end face of the optical fiber. The raised portion may still exist after melting, and the existing melting end apparatus does not have a corresponding detection method.

Disclosure of Invention

In order to solve the technical problems, the invention provides an optical fiber end face detection method, which is realized by the following technical scheme:

an optical fiber end face detection method, an optical fiber is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center; the optical fiber end face is the optical fiber end face after fusion treatment, the edge of the optical fiber end face is provided with arc transition to the end face main body,

acquiring an image shot along the axial direction of the end face of the optical fiber;

a plurality of point light sources; in the axial direction of the optical fiber end face, a plurality of point light sources are positioned in front of the optical fiber end face; when the projection direction is the axial direction of the optical fiber end face, and the plane of the image of the optical fiber end face is taken as a projection plane, the projections of the point light sources are positioned on the concentric circle of the projection of the circle center;

the point light source can generate a light reflecting area on the edge of one side corresponding to the optical fiber end face, and the light reflecting area is imaged on the image of the optical fiber end face;

the point light sources sequentially emit light to obtain images of the end faces of the optical fibers when the point light sources emit light;

detecting the light reflecting areas of the images in the end face of the optical fiber, obtaining the quantity information of the light reflecting areas, and judging that the end face of the optical fiber is unqualified if the quantity of the light reflecting areas in the end face of the optical fiber is detected to be more than or equal to two.

Preferably, detecting the light reflecting region of the image in the end face of the optical fiber includes:

s1: obtaining image information of the end face of the optical fiber, wherein the image information represents bright and dark pixel values;

s2: and performing edge detection to obtain the outline information of the optical fiber end face in the image and the information of the reflecting area in the optical fiber end face.

Preferably, the number of the point light sources is configured to be four.

Preferably, when the number of detected pixels of the highlighted area of the image in the end face of the optical fiber is greater than a set threshold value, it is regarded as a light reflecting area.

The invention also provides an optical fiber end face detection method, wherein the optical fiber is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center; the optical fiber end face is the optical fiber end face after fusion treatment, the edge of the optical fiber end face is provided with arc transition to the end face main body,

acquiring an image shot along the axial direction of the end face of the optical fiber;

a plurality of point light sources; in the axial direction of the optical fiber end face, a plurality of point light sources are positioned in front of the optical fiber end face; when the projection direction is the axial direction of the optical fiber end face and the plane of the optical fiber end face where the image is located is taken as a projection plane, the projections of the point light sources are positioned on the concentric circle of the projection of the circle center; in the projection plane, the projection of the point light source and the projection of the circle center form a virtual straight line, the straight line and the projection outline of the optical fiber end face form two intersection points, the intersection point close to the point light source is a near intersection point, and the intersection point far away from the point light source is a far intersection point;

the point light sources sequentially emit light to obtain images of the end faces of the optical fibers when the point light sources emit light;

detecting a region of a far intersection point of an image in an end face of an optical fiber, and if the region in the end face of the optical fiber in which the far intersection point is detected has a light reflection region, determining that the end face of the optical fiber is not qualified.

Preferably, detecting a region of a far intersection of images within the fiber-optic endface includes:

s1: obtaining image information of the end face of the optical fiber, wherein the image information represents bright and dark pixel values;

s2: and carrying out edge detection to obtain the outline information of the optical fiber end face in the image and whether a reflection area exists in the optical fiber end face of the far intersection point.

Preferably, the number of the point light sources is configured to be four.

Preferably, the image is equally divided in the circumferential direction by taking the physical center of the image or the circle center as the center, the equally divided parts are the same as the number of the point light sources, and the far intersection point is positioned at the middle part of a single equally divided area arc line.

Preferably, when the number of detected pixels of the highlighted area of the image in the end face of the optical fiber is greater than a set threshold value, it is regarded as a light reflecting area.

The invention has the beneficial effects that: the optical fiber end face detection method provided by the invention can be applied to melt end equipment, the optical fiber end face is illuminated in a mode of sequentially lighting and polling a plurality of point light sources, and an image of the optical fiber end face is obtained, and as the melted optical fiber end face is necessarily provided with a crescent reflection area near the point light sources, if reflection is detected in areas except the crescent reflection area, the optical fiber end face is proved to be provided with a flash bulge, and the end face with the flash bulge is an unqualified end face.

Drawings

FIG. 1 shows a schematic diagram of the relative positions of an optical fiber, a point light source, and a camera;

FIG. 2 shows a schematic side view of an optical fiber end face with a flash;

FIG. 3 shows a schematic view of an image of an end face of an optical fiber without a flash;

FIG. 4 shows a schematic view of an image of an end face of an optical fiber with a flash;

fig. 5 shows a schematic view of a line image without a flash on the fiber-optic endface.

Detailed Description

The invention is further described below with reference to the drawings and detailed description.

The equipment adopted by the method is shown in fig. 1, and the optical fiber 1 is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center. The optical fiber end face is the optical fiber end face after the fusion treatment in the prior art, the edge of the optical fiber end face is provided with an arc transition to the end face main body, and impurities such as burrs, dust particles and the like caused by optical fiber cutting can be eliminated on the optical fiber end face after the fusion treatment. As shown in fig. 2, if the fiber end face has a flash, the flash 4 may not disappear after the fusion is completed. Here, fig. 2 is a side view of an optical fiber 1 with a burr 4, and the camera 3 used in this patent is facing the end face of the optical fiber, and the forward end face of the optical fiber is photographed, so that the burr 4 protruding sideways cannot be directly photographed.

In the axial direction of the optical fiber or the optical fiber end face, a plurality of point light sources 2 are located in front of the optical fiber end face. On the projection in the axial direction, a plurality of point light sources 2 are positioned on the concentric circle of the center of the optical fiber. The point light sources 2 may be uniformly distributed on the concentric circle or may be unevenly distributed on the concentric circle. The relative position of the optical fiber is fixed so that the relative coordinates thereof on the image are also fixed, and the position of the point light source 2 is also fixed, and although the optical fiber is manually put into the apparatus, even if the relative position of the optical fiber may have a slight error, the error is small and does not affect the detection result. Meanwhile, in order to prevent the error from being too large, the information of the transverse-longitudinal ratio can be obtained through the profile information of the end face of the optical fiber so as to obtain the center coordinates.

The fiber end face is placed in a closed dark space, and the point light source 2 emits light to impinge on the fiber end face, where the point light source functions to produce light reflection at the curved edge of the fiber end face, rather than a light source that illuminates the entire fiber end face. As shown in fig. 3, since the light source is a point light source and the fiber end face is a circular cross section, the camera 3 located on the front of the fiber end face can only receive the reflection generated by the bent portion of the edge of the fiber end face, and the reflection is a crescent reflection area. The reflection generated at the end face part of the optical fiber end face, which is approximately parallel to the ccd plane of the camera 3, is not received by the camera 3, the back background of the point light source 2, which is far away from the optical fiber end face, can form a white background during imaging, and the imaging of the optical fiber end face can form a dark optical fiber end face image except for the crescent reflection of the rest end face part.

For the number of point light sources, more than two point light sources can be theoretically used, and four point light sources are generally adopted in the actual use process. Although the name point light source is used in this patent, it may also be a parallel light source directed toward the end face of the fiber. The edge must have a certain length and width on the end face, and when a point light source irradiates onto the edge from the front side, the image of the end face of the optical fiber also forms a light reflecting area, and the light reflecting area is a second light reflecting area. Although a point light source may not reflect light from the flash at an angle, the point light source is turned on in sequence, and at least one light source must be capable of generating a second reflection area on the image of the end face of the optical fiber. The point light sources are not uniformly distributed in theory, so long as the irradiation angle can be ensured to enable the flash to be entangled and reflect light on the image, and the uniform distribution of the point light sources is mainly because the influence of visual differences on the image on a user is avoided when the device is imaged.

When the optical fiber end face detection is carried out, the point light sources sequentially emit light, so that the camera 3 can obtain images of the optical fiber end face when the single point light sources emit light. The image may be displayed on the melt-end device via a display screen, and the processor and memory of the melt-end device process the image. And copying pixel data obtained by the camera into a opened calculation area, and carrying out binarization processing on the gray value of the pixel. And when the gray value exceeds the set gray value, the bright point is set, and when the gray value is lower than the set gray value, the black point is set, so that black-and-white image information of the end face of the optical fiber is formed. The contour information of the image can be obtained by edge detection, and thus the region information of the end face of the inner fiber is obtained. And meanwhile, the information of the light reflection area can be obtained by carrying out edge detection on the area of the end face of the optical fiber. A highlight region can be determined by whether or not the highlight pixels are connected to each other and when the number of connected highlight pixels reaches a number. Whether the light reflecting areas are connected or not can be obtained through a maximum connected domain algorithm, and therefore the quantity information of the light reflecting areas is obtained. In calculating the number of light reflecting areas, some noise points caused by equipment noise, error interference or external environment are removed, for example, an area smaller than a specified number of pixels can be defined as noise points, and the noise points are not included in the number of light reflecting areas. Meanwhile, the edge detection can also be to scan outwards from the circle center or scan progressively to detect whether the coordinate or the area representing the bright point exists in the end face of the optical fiber, and as the relative position of the crescent reflective area generated by one point light source and the point light source is fixed, an area representing the area with the necessarily existing reflective effect can be set, and if the bright point exists in the photoelectric end face and is detected out of the area by scanning progressively, the end face of the optical fiber can be judged to have a burr.

Detecting the light reflecting areas of the images in the end face of the optical fiber, obtaining the quantity information of the light reflecting areas, and judging that the end face of the optical fiber is unqualified if the quantity of the light reflecting areas in the end face of the optical fiber is detected to be more than or equal to two. When a point light source emits light, the end face of the optical fiber inevitably generates a crescent reflection on the side close to the light source, as shown in fig. 4, if the reflection area 5 is also arranged on the image, the image proves that the image shows that the end face of the optical fiber has a convex burr. If the fiber end face is acceptable, as shown in FIG. 3, the image will show only one light reflecting area without the flash.

Because the reflection angle that can produce by a pointolite is limited, but when a plurality of pointolite evenly distributed, a plurality of pointolite lights the polling in proper order, must have at least one pointolite can make the burr form the reflection of light region on the image.

Another embodiment provided by this patent is because when a point light source emits light, the fiber end face must create a crescent shaped light reflecting area on the side near the light source. Since the flash is typically located at the edge of the fiber end face, it is theorized that the reflective area on the image is most pronounced when the flash is located furthest relative to the point source. Because a plurality of point light sources are adopted, the relative position of at least one point light source and the flash is farthest. Therefore, in order to reduce the calculation amount, it is only necessary to detect whether the reflection area exists in the area of the inner distal end of the fiber end face corresponding to the crescent reflection area formed by one point light source.

For convenience of explanation, the relative position is replaced by a virtual model, specifically, as shown in fig. 5, in the projection plane, the virtual straight line formed by the point light source and the center of the circle is located, the straight line forms two intersecting points with the edge of the end face of the optical fiber, the intersecting point close to the point light source is a near intersecting point, the intersecting point far from the point light source is a far intersecting point 5, and when the point light source is on, the area of the end face of the optical fiber close to the near intersecting point can necessarily generate a reflection area formed by the point light source, so that the reflection is not required to be detected.

In this case, only the region of the far intersection point 5 of the image in the end face of the optical fiber is detected, and since the relative position of the light source is fixed, a fixed detection region a may be provided in the region of the corresponding far intersection point 5, and if the region in the end face of the optical fiber in which the far intersection point 5 is detected has a light reflection region or a plurality of light reflection points are detected, it is determined that the end face of the optical fiber is not acceptable. Since the positions and the number of the point light sources in the image are fixed in physical sense, the relative positions of the point light sources in the image can be predicted after the equipment is manufactured, if the point light sources are three point light sources, the point light sources can be trisected in advance along the circumferential direction by taking the physical center of the image or taking the circle center as the center, and the area at the far intersection point is positioned at the middle part of a single equally divided area arc line. When the detection is carried out, only the area in the optical fiber end face of the image at the corresponding far intersection point can be detected, and the operation amount is greatly reduced.

The method is that a preset detection area is arranged in the equipment, if a real-time detection and division area mode is adopted, the circle center of the optical fiber end face in the optical fiber end face image is required to be detected, at the moment, after the edge detection is carried out to obtain the information of the outline of the optical fiber end face, the circle center coordinate is found according to the aspect ratio of the image, then a corresponding far intersection point is found according to the circle center coordinate and the coordinate of a pre-known point light source, whether a reflection area exists at the far intersection point is detected according to a preset threshold value, at the moment, if the reflection area is detected, the optical fiber end face is proved to have a burr, and if the reflection area is not detected, the optical fiber end face is proved to be qualified.

Claims (9)

1. An optical fiber end face detection method, an optical fiber is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center; the optical fiber end face is the optical fiber end face after fusion treatment, and the edge of the optical fiber end face is provided with an arc transition to the end face main body, and is characterized in that:

acquiring an image shot along the axial direction of the end face of the optical fiber;

a plurality of point light sources; in the axial direction of the optical fiber end face, a plurality of point light sources are positioned in front of the optical fiber end face; when the projection direction is the axial direction of the optical fiber end face, and the plane of the image of the optical fiber end face is taken as a projection plane, the projections of the point light sources are positioned on the concentric circle of the projection of the circle center;

the point light source can generate a light reflecting area on the edge of one side corresponding to the optical fiber end face, and the light reflecting area is imaged on the image of the optical fiber end face;

the point light sources sequentially emit light to obtain images of the end faces of the optical fibers when the point light sources emit light;

detecting the light reflecting areas of the images in the end face of the optical fiber, obtaining the quantity information of the light reflecting areas, and judging that the end face of the optical fiber is unqualified if the quantity of the light reflecting areas in the end face of the optical fiber is detected to be more than or equal to two.

2. The method for detecting an end face of an optical fiber according to claim 1, wherein:

detecting the light reflecting region of the image within the fiber end face includes:

s1: obtaining image information of the end face of the optical fiber, wherein the image information represents bright and dark pixel values;

s2: and performing edge detection to obtain the outline information of the optical fiber end face in the image and the information of the reflecting area in the optical fiber end face.

3. The method for detecting an end face of an optical fiber according to claim 1, wherein:

the number of the point light sources is configured to be four.

4. A fiber-optic endface detection method according to any one of claims 1-3, wherein:

and when the number of the detected pixel points of the highlight region of the image in the end face of the optical fiber is larger than a set threshold value, the detected pixel points are regarded as a light reflecting region.

5. An optical fiber end face detection method, an optical fiber is provided with an optical fiber end face, and the optical fiber end face is provided with a circle center; the optical fiber end face is the optical fiber end face after fusion treatment, and the edge of the optical fiber end face is provided with an arc transition to the end face main body, and is characterized in that:

acquiring an image shot along the axial direction of the end face of the optical fiber;

a plurality of point light sources; in the axial direction of the optical fiber end face, a plurality of point light sources are positioned in front of the optical fiber end face; when the projection direction is the axial direction of the optical fiber end face and the plane of the optical fiber end face where the image is located is taken as a projection plane, the projections of the point light sources are positioned on the concentric circle of the projection of the circle center; in the projection plane, the projection of the point light source and the projection of the circle center form a virtual straight line, the straight line and the projection outline of the optical fiber end face form two intersection points, the intersection point close to the point light source is a near intersection point, and the intersection point far away from the point light source is a far intersection point;

the point light sources sequentially emit light to obtain images of the end faces of the optical fibers when the point light sources emit light;

detecting a region of a far intersection point of an image in an end face of an optical fiber, and if the region in the end face of the optical fiber in which the far intersection point is detected has a light reflection region, determining that the end face of the optical fiber is not qualified.

6. The method for detecting an end face of an optical fiber according to claim 5, wherein:

detecting the region of the distal intersection of the images within the fiber-optic endface includes:

s1: obtaining image information of the end face of the optical fiber, wherein the image information represents bright and dark pixel values;

s2: and carrying out edge detection to obtain the outline information of the optical fiber end face in the image and whether a reflection area exists in the optical fiber end face of the far intersection point.

7. The method for detecting an end face of an optical fiber according to claim 5, wherein:

the number of the point light sources is configured to be four.

8. The method for detecting an end face of an optical fiber according to claim 5, wherein:

and equally dividing the image along the circumferential direction by taking the physical center of the image or the circle center as the center, wherein the equally divided parts are the same as the point light sources in number, and the far intersection point is positioned in the middle of a single equally divided area arc line.

9. The optical fiber end face detection method according to any one of claims 5 to 8, characterized in that:

and when the number of the detected pixel points of the highlight region of the image in the end face of the optical fiber is larger than a set threshold value, the detected pixel points are regarded as a light reflecting region.