CN109146968B - Panda type polarization maintaining optical fiber end face axis fixing method and device - Google Patents
Panda type polarization maintaining optical fiber end face axis fixing method and device Download PDFInfo
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Abstract
The embodiment of the invention provides a panda type polarization maintaining optical fiber end face axis determining method and device, wherein the method comprises the following steps: extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye; converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image; and calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber. According to the method and the device provided by the embodiment of the invention, the cat eye image is extracted from the end face image through the ROI segmentation technology, so that the subsequent calculation amount for acquiring the cat eye coordinate is reduced, the calculation time is shortened, and the instantaneity of the polarization maintaining optical fiber end face axis fixing method is enhanced.
Description
Technical Field
The embodiment of the invention relates to the technical field of photoelectrons, in particular to a panda type polarization maintaining optical fiber end face axis fixing method and device.
Background
The polarization maintaining optical fiber is a special optical fiber with important use value, has strong polarization maintaining capability to polarized light vibrating along the polarization axis direction, and is widely applied to the fields of optical communication and optical fiber sensing.
In the application of polarization maintaining optical fibers, especially in the manufacturing process of polarization maintaining optical fiber devices, the precision requirement on the coupling or welding angle of the polarization axes of two polarization maintaining optical fibers is high, so that the accurate determination of the polarization axis of the polarization maintaining optical fiber is a key technology in the application.
The method for determining the polarization axis of the polarization-maintaining optical fiber by utilizing the image processing technology is divided into a side-view imaging method and an end-face imaging method, wherein the end-face imaging method has the defects of large calculation amount and long calculation time, and is not suitable for occasions with higher real-time requirements on the axis fixing process.
Disclosure of Invention
The embodiment of the invention provides a panda type polarization maintaining optical fiber end face axis fixing method and device, which are used for solving the problem of poor real-time performance of the existing polarization maintaining optical fiber end face axis fixing method.
In one aspect, an embodiment of the present invention provides a method for determining an axis of an end face of a panda-type polarization maintaining fiber, including:
extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye;
converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image;
and calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber.
In another aspect, an embodiment of the present invention provides a panda-type polarization maintaining fiber end face centering device, including:
the image extraction unit is used for extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of the cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye;
the central coordinate acquisition unit is used for converting the cat eye image into a cat eye binary image and acquiring the central coordinate of the first cat eye and the central coordinate of the second cat eye based on the cat eye binary image;
and the axis fixing unit is used for calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye so as to finish the axis fixing of the end face of the polarization-maintaining optical fiber.
In another aspect, an embodiment of the present invention provides a panda-type polarization maintaining fiber end surface axis fixing device, including a processor, a communication interface, a memory and a bus, where the processor, the communication interface, and the memory complete mutual communication through the bus, and the processor can call a logic instruction in the memory to execute the aforementioned panda-type polarization maintaining fiber end surface axis fixing method.
In yet another aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the panda-type polarization maintaining fiber end face axis fixing method as described above.
According to the panda type polarization maintaining optical fiber end face axis fixing method and device provided by the embodiment of the invention, the cat eye image is extracted from the end face image through the ROI segmentation technology, the subsequent calculation amount for obtaining the cat eye coordinate is reduced, the calculation time is shortened, and the instantaneity of the polarization maintaining optical fiber end face axis fixing method is enhanced.
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, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic flow chart of a panda-type polarization maintaining fiber end surface axis fixing method according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a panda-type polarization maintaining fiber end surface axis fixing method according to an embodiment of the present invention;
FIG. 3 is an end-face grayscale image of an embodiment of the invention;
FIG. 4 is a schematic diagram of a fitting result of a circle of a point at the edge of a cladding of a panda-type polarization maintaining fiber according to an embodiment of the present invention;
FIG. 5 is a cat-eye image of an embodiment of the invention;
FIG. 6 is a cat-eye binary image according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of fitting results of cat eye circles of panda-type polarization maintaining optical fibers according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a panda-type polarization maintaining fiber end surface centering device according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an end face alignment apparatus for panda-type polarization maintaining optical fibers according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. 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.
Aiming at the defects of large calculated amount and long calculating time of the existing polarization maintaining optical fiber end face axis fixing method and being not suitable for occasions with higher real-time requirements on the axis fixing process, the embodiment of the invention provides an end face axis fixing method for a panda type polarization maintaining optical fiber, which is beneficial to improving the axis fixing speed, and fig. 1 is a flow schematic diagram of the panda type polarization maintaining optical fiber end face axis fixing method in the embodiment of the invention, and as shown in fig. 1, the method comprises the following steps:
101, extracting a cat eye image from an end face image by an ROI image segmentation technology based on the coordinates of a cladding center in the end face image of the polarization maintaining optical fiber to be axis-fixed and the position relation between the cladding center and the cat eye.
The ROI (region of interest) is an interesting region, the ROI selected based on the coordinates of the center of a cladding in an end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and a cat eye is a cat eye region in the end face image, two cat eyes (a first cat eye and a second cat eye) in the end face image are separated based on an ROI image segmentation technology, and the two cat eyes are stored as cat eye images. Here, the cat eye image is an image including the first cat eye and the second cat eye extracted from the end face image based on the ROI image segmentation technique.
Note that the first cat eye and the second cat eye are used only for distinguishing the two cat eyes in the end face image.
And 102, converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image.
Here, the cat-eye binary image refers to an image obtained after the gradation value of each pixel on the cat-eye image is set to 0 or 255. Here, there are various methods for obtaining the center coordinates of the first cat eye and the second cat eye based on the cat eye binary image, for example, an edge point set of the first cat eye in the cat eye binary image is obtained through edge detection, and circle center fitting is performed based on the edge point set of the first cat eye to obtain the center coordinate of the first cat eye.
103, calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinates of the first cat eye and the second cat eye, and completing the axis fixing of the end face of the polarization-maintaining optical fiber.
In the embodiment of the invention, the cat eye image is extracted from the end face image by the ROI segmentation technology, so that the subsequent calculation amount for acquiring the cat eye coordinate is reduced, the calculation time is shortened, and the instantaneity of the polarization maintaining optical fiber end face axis fixing method is enhanced.
Based on the above embodiment, a method 101 for fixing an end surface of a panda-type polarization maintaining fiber, based on coordinates of a center of a cladding in an end surface image of a polarization maintaining fiber to be fixed and a positional relationship between the center of the cladding and a cat eye, extracts a cat eye image from the end surface image by using an ROI image segmentation technology, and before that, further includes:
converting the end face image into an end face binary image; and acquiring the cladding center coordinates of the polarization maintaining optical fiber based on the end face binary image.
Specifically, when image segmentation is performed, the region of interest ROI needs to be determined by the coordinates of the center of the cladding and the positional relationship between the center of the cladding and the cat eye, and thus, the coordinates of the center of the cladding need to be determined before that. Here, the end face binary image refers to an image obtained after the gradation value of each pixel on the end face image is set to 0 or 255. The method for obtaining the cladding center coordinates of the polarization maintaining fiber based on the end face binary image includes a plurality of methods, for example, obtaining a cladding edge point set through edge detection, and performing circle center fitting based on the cladding edge point set to obtain the cladding center coordinates.
Based on any of the embodiments, a panda-type polarization maintaining fiber end face axis fixing method 101 extracts a cat eye image from an end face image by an ROI image segmentation technology based on a cladding center coordinate and a positional relationship between a cladding center and a cat eye, and specifically includes:
all pixel points meeting the following formula are extracted from the end face image to form a cat eye image:
in the formula, A is a pixel point set of the cat eye image, (x, y) is any pixel point in the cat eye image, and x0And y0Respectively, the abscissa and ordinate of the center of the cladding, and Radius is the maximum distance between the center of the cladding and the edge of the cat eye.
Specifically, the positional relationship between the center of the cladding and the cat eye specifically refers to the distance between the center of the cladding and the edge of the cat eye. According to the above formula, the region of interest ROI can be determined as a circle with Radius around the center of the cladding. Preferably, all the pixels satisfying the above formula in the end face image may be retained, and all the portions not satisfying the above formula in the end face image may be filled in white, and then a rectangle (x) may be passed through0-Radius,y0Radius,2 Radius) to divide all pixels satisfying the above formula from the end face image, and store them as Mat typeThe image of the model is also referred to as a cat eye image.
In the existing polarization maintaining optical fiber end face axis fixing method, the side-looking imaging method has the defects of strict requirement on the imaging plane distance, large axis fixing error and the like, and in order to solve the problems, based on any of the above embodiments, a panda type polarization maintaining optical fiber end face axis fixing method 102 converts a cat eye image into a cat eye binary image, and specifically includes:
1) and acquiring a cat eye threshold value of the cat eye image by a peak-valley value searching method based on the gray level histogram of the cat eye image.
The gray level histogram is a function of gray level distribution in the cat-eye image, and is statistics of the gray level distribution in the cat-eye image. The gray histogram is obtained by counting the occurrence frequency of all pixels in the cat eye image according to the gray value. The peak-valley value searching method includes the steps of finding all peaks and all valley points between adjacent peaks in a gray histogram by analyzing the gray histogram, storing pixel gray values corresponding to all valley points in a gray threshold value array, sequencing elements in the gray threshold value array according to the number of image pixels corresponding to the gray values at the valley points, arranging the gray value corresponding to the valley point with the largest number of image pixels at the head of the gray threshold value array, and so on, traversing to all the valley points, and taking the gray value at the head of the gray threshold value array as a peep hole threshold value.
2) And converting the cat eye image into a cat eye binary image based on the cat eye threshold value.
In addition, the method can further comprise the following steps: after obtaining the cat eye binary image, judging whether the current cat eye binary image meets a preset condition: and if the current cat eye binary image does not meet the preset condition, circulating convenience near the cat eye threshold value, updating the gray threshold value array, acquiring a new cat eye threshold value, and carrying out binarization until a binary image which meets the preset requirement and contains two cat eyes is obtained.
In the embodiment of the invention, the cat eye binary image is obtained by the gray level histogram peak-valley value searching method, and compared with a general binary image obtaining method, a more appropriate cat eye threshold value can be obtained, so that a more accurate binary image is provided for the subsequent calculation of the cat eye center, and the accuracy of the polarization maintaining optical fiber end face axis fixing method is improved.
In order to solve the above problems, based on any one of the embodiments, an axis determining method for a panda-type polarization maintaining optical fiber end surface 102, based on a cat eye binary image, obtains a center coordinate of a first cat eye and a center coordinate of a second cat eye, and specifically includes:
1) and acquiring a contour point set of the first cat eye and a contour point set of the second cat eye by finding a contour operator based on the cat eye binary image.
Here, a contour operator, findcontours function, is found for retrieving contours from the binary image and returning the number of detected contours. In the embodiment of the invention, the contour point set of the first cat eye and the contour point set of the second cat eye are obtained by finding a contour operator.
2) Performing circle fitting on the contour point set of the first cat eye based on an iterative least square method to obtain a central coordinate of the first cat eye; and performing circle fitting on the contour point set of the second cat eye based on an iterative least square method to obtain the central coordinate of the second cat eye.
Specifically, taking the contour point set of the first cat eye as an example, the circle center of the circle fitted by the contour point set based on the first cat eye is continuously updated by a multiple iteration least square circle fitting method, so that the existing interference points are filtered, but some points on the real edge are excluded as non-edge points, so that the points on the real circle in the point set are reduced. Points are re-fetched by using the method of returning to the original first cat eye contour point set, the points deleted by mistake are selected again to participate in iteration, the circle center obtained by fitting is closer to the real circle center, and the removal of the stray points is faster. Here, the center of the circle obtained by the iterative least square fitting is the center of the first cat eye. The fitting method of the second cat-eye center is the same as above, and is not described herein again.
In the embodiment of the invention, the contour point set of the first cat eye and the contour point set of the second cat eye are obtained by finding the contour operator, and the center coordinates of the first cat eye and the second cat eye are obtained by performing circle fitting through an iterative least square method.
Based on any of the embodiments, a panda-type polarization maintaining fiber end face axis fixing method 103 calculates a polarization angle of a polarization maintaining fiber based on a center coordinate of a first cat eye and a center coordinate of a second cat eye, and specifically includes:
the polarization angle of the polarization maintaining fiber is calculated by the following formula:
in the formula, theta is the polarization angle of the polarization maintaining fiber, x1And y1Respectively the abscissa and ordinate, x, of the center of the first cat eye2And y2Respectively the abscissa and ordinate of the center of the second cat eye.
Based on any one of the above embodiments, a panda-type polarization maintaining optical fiber end face dead axle method converts an end face image of a polarization maintaining optical fiber to be dead axle into an end face binary image, and specifically includes:
1) the end face image is converted into an end face grayscale image.
It should be noted that there are various methods for converting the end face image into the end face grayscale image, such as a floating point algorithm, an integer method, and an arithmetic method, and the embodiment of the present invention is not limited to this.
2) And acquiring an end face threshold value of the end face gray level image by a peak-valley value searching method based on the gray level histogram of the end face gray level image.
The gray level histogram is a function of the gray level distribution in the end face gray level image, and is a statistic of the gray level distribution in the end face gray level image. The gray histogram is obtained by counting the frequency of occurrence of all pixels in the end face gray image according to the gray value. The peak-valley value searching method includes the steps of finding all peaks and all valley points between adjacent peaks in a gray histogram by analyzing the gray histogram, storing pixel gray values corresponding to all valley points in a gray threshold value array, sequencing elements in the gray threshold value array according to the number of image pixels corresponding to the gray values at the valley points, arranging the gray value corresponding to the valley point with the largest number of image pixels at the head of the gray threshold value array, and so on, traversing to all the valley points, and taking the gray value at the head of the gray threshold value array as an end surface threshold value.
3) And converting the end face gray level image into an end face binary image based on the end face threshold value.
In addition, the method can further comprise the following steps: after the end face binary image is obtained, judging whether the current end face binary image meets a preset condition: if the current end face binary image does not meet the preset condition, circulation is facilitated near the end face threshold value, the gray threshold value array is updated, and a new end face threshold value is obtained for binarization until the end face binary image meeting the preset requirement is obtained.
In the embodiment of the invention, the end face binary image is obtained by the gray level histogram peak-valley value searching method, and compared with a general binary image obtaining method, a more appropriate end face threshold value can be obtained, so that a more accurate binary image is provided for the subsequent calculation of the cladding center, and the accuracy of the polarization maintaining optical fiber end face axis fixing method is improved.
Based on any one of the embodiments, a panda-type polarization maintaining optical fiber end face axis fixing method obtains a cladding center coordinate of a polarization maintaining optical fiber based on an end face binary image, and specifically includes:
1) and acquiring a cladding contour point set of the polarization maintaining optical fiber by finding a contour operator based on the end face binary image.
Here, a contour operator, findcontours function, is found for retrieving contours from the binary image and returning the number of detected contours. In the embodiment of the invention, the set of cladding contour points is obtained by finding a contour operator.
2) And performing circle fitting on the cladding contour point set based on an iterative least square method to obtain the cladding center coordinate of the polarization-maintaining optical fiber.
Specifically, the circle center of the circle fitted based on the cladding contour point set is continuously updated through a multi-iteration least square circle fitting method, existing interference points are filtered, but some points on the real edge are excluded as non-edge points, so that the points on the real circle in the point set are reduced. Points are re-fetched by using a method of returning to an original cladding contour point set, points deleted by mistake are re-selected to participate in iteration, the circle center obtained by fitting is closer to the real circle center, and the removal of stray points is faster. Here, the center of the circle obtained by the iterative least squares fitting is the cladding center.
In the embodiment of the invention, the cladding contour point set is obtained by finding the contour operator, the circle fitting is carried out by the iterative least square method, and the cladding center coordinate is obtained.
For better understanding and application of the method for dead-end alignment of panda-type polarization maintaining optical fiber, the present invention is exemplified below, and the present invention is not limited to the following examples.
Fig. 2 is a schematic flow chart of a method for dead axle of a panda-type polarization maintaining optical fiber end face according to an embodiment of the present invention, and as shown in fig. 2, the method for dead axle of the panda-type polarization maintaining optical fiber end face includes:
fig. 3 is an end face grayscale image of an embodiment of the invention. Firstly, an end face image ImFiber of a panda type polarization maintaining optical fiber to be fixed in a clear imaging mode is obtained, a rectangular coordinate system is established by taking the upper left corner point of the image as an origin, and the end face image ImFiber is converted into an end face gray image ImFiberGray shown in figure 3.
And obtaining an end face threshold value OptimeExternThre which is 14 for converting the end face gray image ImFiberGray into the end face binary image ImBin by using a gray histogram-based peak-valley value searching method, and converting the end face gray image ImFiberGray into the end face binary image ImBin based on the end face threshold value OptimeExternThre.
Aiming at the end face binary image ImBin, a cladding contour point set selected contacts of the polarization maintaining fiber is obtained based on a profile finding operator findcontours, the central coordinate of the cladding of the polarization maintaining fiber is obtained by using iterative least square method circle fitting (1143,530), the radius of the cladding is 270, and the result of the fiber cladding edge point circle fitting is shown in FIG. 4.
In the end face grayscale image ImFiberGray, with a cladding center (1143,530) of the polarization maintaining fiber as a center of a circle and a distance from (1143,530) to the left and right edges of the two cat eyes, that is, a maximum distance Radius between the cladding center and the cat eye edge being 210 as a Radius, all pixel points satisfying the following formula in the end face image are retained, all parts not satisfying the following formula in the end face image are filled into white, then all pixel points satisfying the following formula are segmented from the end face grayscale image ImFiberGray by rectangles (933, 320, 420, 420) and stored as an image of Mat type, that is, a cat eye image ImFiberRoi, fig. 5 is a cat eye image of the embodiment of the present invention:
in the formula, a is a pixel point set of the cat eye image, and (x, y) is any pixel point in the cat eye image.
The segmented cat eye image ImFiberRoi is obtained by converting the cat eye image ImFiberRoi into a cat eye binary image ImFiberRoiBin by a gray histogram peak-valley value search method, wherein a cat eye threshold optimppandarthre is 202, and fig. 6 is the cat eye binary image ImFiberRoiBin in the embodiment of the present invention. For a binary image ImFiberRoiBin of a cat eye, finding a set of contour points leftpandataset of a first cat eye and a set of contour points rightpandataset of a second cat eye by finding contour operators findcontours, and obtaining a center coordinate (120.07, 272.28) of the first cat eye and a center coordinate (303.96,152.71) of the second cat eye by using an iterative least square circle fitting method, wherein the result of the round fitting of the cat eye of the optical fiber is shown in fig. 7.
And (3) calculating to obtain the current polarization axis angle theta of the panda polarization-maintaining fiber by adopting a formula theta of arctan ((152.71-272.28)/303.96-120.07), wherein the current polarization axis angle theta is 32.909 degrees, and the axis fixing of the end face of the panda polarization-maintaining fiber is completed.
In the example, the cat eye image is extracted from the end face image through the ROI segmentation technology, so that the subsequent calculation amount for acquiring the cat eye coordinate is reduced, the calculation time is shortened, and the instantaneity of the polarization maintaining optical fiber end face axis fixing method is enhanced.
In addition, the cat eye binary image is obtained through the gray level histogram peak-valley value searching method, compared with a general binary image obtaining method, a more appropriate cat eye threshold value can be obtained, a more accurate binary image is provided for subsequent calculation of the center of the cat eye, and the accuracy of the polarization maintaining optical fiber end face axis fixing method is improved.
Meanwhile, a contour operator is found to obtain a contour point set of the first cat eye and a contour point set of the second cat eye, circle fitting is carried out through an iterative least square method, and center coordinates of the first cat eye and the second cat eye are obtained.
Based on any one of the above method embodiments, fig. 8 is a schematic structural diagram of a panda-type polarization maintaining optical fiber end surface axis fixing device according to an embodiment of the present invention, and as shown in fig. 8, the panda-type polarization maintaining optical fiber end surface axis fixing device includes:
an image extraction unit 801, configured to extract a cat eye image from an end face image by using an ROI image segmentation technique based on coordinates of a cladding center in the end face image of the polarization maintaining fiber to be axis-fixed and a positional relationship between the cladding center and the cat eye;
a central coordinate obtaining unit 802, configured to convert the cat eye image into a cat eye binary image, and obtain a central coordinate of the first cat eye and a central coordinate of the second cat eye based on the cat eye binary image;
and an axis fixing unit 803, configured to calculate a polarization angle of the polarization maintaining optical fiber based on the center coordinate of the first cat eye and the center coordinate of the second cat eye, and complete axis fixing of the end face of the polarization maintaining optical fiber.
It should be noted that, the image extraction unit 801, the central coordinate acquisition unit 802, and the axis fixing unit 803 cooperate to execute the method for axis fixing of the end face of the panda-type polarization maintaining fiber in the foregoing embodiment, and specific functions of the system refer to the above embodiment of the method for axis fixing of the end face of the panda-type polarization maintaining fiber, which is not described herein again.
In the embodiment of the invention, the cat eye image is extracted from the end face image by the ROI segmentation technology, so that the subsequent calculation amount for acquiring the cat eye coordinate is reduced, the calculation time is shortened, and the instantaneity of the polarization maintaining optical fiber end face axis fixing method is enhanced.
Based on any one of the above embodiments, a panda type polarization maintaining optical fiber end face dead axle device further includes:
the cladding center acquisition unit is used for converting the end face image into an end face binary image; and acquiring the cladding center coordinates of the polarization maintaining optical fiber based on the end face binary image.
Based on any of the above embodiments, in a panda-type polarization maintaining fiber end surface alignment apparatus, the image extraction unit 801 is specifically configured to:
all pixel points meeting the following formula are extracted from the end face image to form a cat eye image:
in the formula, A is a pixel point set of the cat eye image, (x, y) is any pixel point in the cat eye image, and x0And y0Respectively, the abscissa and ordinate of the center of the cladding, and Radius is the maximum distance between the center of the cladding and the edge of the cat eye.
Based on any of the above embodiments, a panda-type polarization maintaining fiber end surface centering device, the central coordinate obtaining unit 802 specifically includes:
the cat eye binary conversion subunit is used for acquiring a cat eye threshold value of the cat eye image by a peak-valley value searching method based on the gray level histogram of the cat eye image; converting the cat eye image into a cat eye binary image based on a cat eye threshold value;
the cat eye center acquisition subunit is used for acquiring a contour point set of the first cat eye and a contour point set of the second cat eye by finding a contour operator based on the cat eye binary image; performing circle fitting on the contour point set of the first cat eye based on an iterative least square method to obtain a central coordinate of the first cat eye; and performing circle fitting on the contour point set of the second cat eye based on an iterative least square method to obtain the central coordinate of the second cat eye.
Based on any one of the above embodiments, a panda-type polarization maintaining fiber end surface dead axle device, dead axle unit 803, is specifically configured to:
the polarization angle of the polarization maintaining fiber is calculated by the following formula:
in the formula, theta is the polarization angle of the polarization maintaining fiber, x1And y1Respectively the abscissa and ordinate, x, of the center of the first cat eye2And y2Respectively the abscissa and ordinate of the center of the second cat eye.
Based on any one of the above embodiments, a panda type polarization maintaining fiber end face dead axle device, cladding center acquisition unit specifically includes:
the end face binary conversion subunit is used for converting the end face image into an end face gray level image; acquiring an end face threshold value of the end face gray level image by a peak-valley value searching method based on a gray level histogram of the end face gray level image; converting the end face gray level image into an end face binary image based on an end face threshold value;
the cladding center acquisition subunit is used for acquiring a cladding contour point set of the polarization maintaining optical fiber through a contour finding operator based on the end face binary image; and performing circle fitting on the cladding contour point set based on an iterative least square method to obtain the cladding center coordinate of the polarization-maintaining optical fiber.
Fig. 9 is a schematic structural diagram of an end surface alignment apparatus for panda-type polarization maintaining fiber according to an embodiment of the present invention, and as shown in fig. 9, the end surface alignment apparatus for panda-type polarization maintaining fiber includes: a processor (processor)901, a communication Interface (Communications Interface)902, a memory (memory)903 and a bus 904, wherein the processor 901, the communication Interface 902 and the memory 903 are communicated with each other via the bus 904. The processor 901 may call logic instructions in the memory 903 to perform methods including, for example: extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye; converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image; and calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber.
An embodiment of the present invention discloses a computer program product, which includes a computer program stored on a non-transitory computer readable storage medium, where the computer program includes program instructions, and when the program instructions are executed by a computer, the computer can execute the method provided by the above method embodiments, for example, the method includes: extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye; converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image; and calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber.
The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause a computer to perform the methods provided by the above method embodiments, for example, including: extracting a cat eye image from the end face image through an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed in axis and the position relation between the center of the cladding and the cat eye; converting the cat eye image into a cat eye binary image, and acquiring the center coordinate of the first cat eye and the center coordinate of the second cat eye based on the cat eye binary image; and calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber.
Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
The above-described embodiments of the communication device and the like are merely illustrative, and units illustrated as separate components may or may not be physically separate, and components displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments or some parts of the embodiments.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention, and are not limited thereto; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. A panda type polarization maintaining optical fiber end face axis fixing method is characterized by comprising the following steps:
extracting a cat eye image from the end face image of the polarization maintaining optical fiber to be fixed by an ROI image segmentation technology based on the coordinates of the center of a cladding in the end face image of the polarization maintaining optical fiber to be fixed and the position relation between the center of the cladding and the cat eye;
converting the cat eye image into a cat eye binary image, and acquiring a center coordinate of a first cat eye and a center coordinate of a second cat eye based on the cat eye binary image;
calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye, and finishing the axis fixing of the end face of the polarization-maintaining optical fiber;
based on the cladding center coordinates and the positional relationship between the cladding center and the cat eye, extracting a cat eye image from the end face image by an ROI image segmentation technology specifically comprises the following steps:
extracting all pixel points meeting the following formula from the end face image to form the cat eye image:
in the formula, A is a pixel point set of the cat eye image, and (x, y) is any pixel point in the cat eye image, x0And y0Respectively, the abscissa and the ordinate of the center of the cladding, and Radius is the maximum distance between the center of the cladding and the edge of the cat eye.
2. The method of claim 1, wherein the extracting the cat eye image from the end face image by the ROI image segmentation technique based on the coordinates of the cladding center in the end face image of the polarization-maintaining fiber to be axis-fixed and the positional relationship between the cladding center and the cat eye further comprises:
converting the end face image into an end face binary image;
and acquiring the cladding center coordinate of the polarization maintaining optical fiber based on the end face binary image.
3. The method according to claim 1 or 2, wherein the converting the cat-eye image into a cat-eye binary image specifically comprises:
based on the gray level histogram of the cat eye image, acquiring a cat eye threshold value of the cat eye image by a peak-valley value searching method;
and converting the cat eye image into a cat eye binary image based on the cat eye threshold value.
4. The method according to claim 1 or 2, wherein the obtaining of the center coordinates of the first cat eye and the center coordinates of the second cat eye based on the cat eye binary image specifically includes:
based on the cat eye binary image, acquiring a contour point set of a first cat eye and a contour point set of a second cat eye by finding a contour operator;
performing circle fitting on the contour point set of the first cat eye based on an iterative least square method to obtain a central coordinate of the first cat eye; and performing circle fitting on the contour point set of the second cat eye based on an iterative least square method to obtain the central coordinate of the second cat eye.
5. The method according to claim 1 or 2, wherein the calculating the polarization angle of the polarization maintaining fiber based on the center coordinates of the first cat eye and the center coordinates of the second cat eye comprises:
calculating the polarization angle of the polarization maintaining fiber by:
in the formula, theta is the polarization angle of the polarization-maintaining fiber, x1And y1Respectively, the abscissa and ordinate, x, of the center of the first cat eye2And y2Respectively being the abscissa and ordinate of the second cat eye center.
6. The method according to claim 2, wherein converting the end face image of the polarization maintaining fiber to be fixed in axis into an end face binary image comprises:
converting the end face image into an end face gray level image;
acquiring an end face threshold value of the end face gray level image by a peak-valley value searching method based on the gray level histogram of the end face gray level image;
converting the end face grayscale image into an end face binary image based on the end face threshold value;
the obtaining of the cladding center coordinate of the polarization maintaining fiber based on the end face binary image specifically includes:
acquiring a cladding contour point set of the polarization maintaining optical fiber by finding a contour operator based on the end face binary image;
and performing circle fitting on the cladding contour point set based on an iterative least square method to obtain the cladding center coordinate of the polarization-maintaining optical fiber.
7. A panda type polarization maintaining optical fiber end face dead axle device is characterized by comprising:
the image extraction unit is used for extracting a cat eye image from the end face image of the polarization maintaining optical fiber to be fixed in axis through an ROI image segmentation technology based on the coordinates of the center of the cladding in the end face image and the position relation between the center of the cladding and the cat eye;
the central coordinate acquisition unit is used for converting the cat eye image into a cat eye binary image and acquiring the central coordinate of the first cat eye and the central coordinate of the second cat eye based on the cat eye binary image;
the axis fixing unit is used for calculating the polarization angle of the polarization-maintaining optical fiber based on the central coordinate of the first cat eye and the central coordinate of the second cat eye so as to finish the axis fixing of the end face of the polarization-maintaining optical fiber;
the image extraction unit is specifically configured to extract all pixel points satisfying the following formula from the end face image to form the cat eye image:
in the formula, A is a pixel point set of the cat eye image, and (x, y) is any pixel point in the cat eye image, x0And y0Respectively, the abscissa and the ordinate of the center of the cladding, and Radius is the maximum distance between the center of the cladding and the edge of the cat eye.
8. A panda type polarization maintaining optical fiber end face axis fixing device, which comprises a processor, a communication interface, a memory and a bus, wherein the processor, the communication interface and the memory are communicated with each other through the bus, and the processor can call logic instructions in the memory to execute the panda type polarization maintaining optical fiber end face axis fixing method according to any one of claims 1 to 6.
9. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method for end-face alignment of panda-type polarization maintaining fibers according to any one of claims 1 to 6.
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