An automatic focusing algorithm and an arc characteristic value extraction method based on the algorithm

Abstract

The application provides an automatic focusing algorithm, which is applied to the technical field of optical fiber fusion machines and obtains the best imaging of an electric arc by changing the focal length according to the slope of the edge of an optical fiber and comprises the following steps: a single-step running focusing motor, calculation of the slope of the edge of the optical fiber and the maximum brightness of the edge of the optical fiber at each step in the running; acquisition of the maximum value of the slope of the edge of the optical fiber and storage of the maximum brightness of the edge of the optical fiber corresponding to the running step number at this time; recording of all the running step numbers corresponding to the slope of the edge of the optical fiber and the maximum slope to the edge qualified step number array; acquisition of the maximum brightness of the edge of the optical fiber corresponding to the running step number; determination of the maximum value in the maximum brightness of the edge of the optical fiber, and the corresponding running number is the final target running step number. In another aspect, the application provides an extraction method for the characteristic value of an electric arc, which uses the automatic focusing algorithm and acquires the characteristic value of the electric arc according to different methods corresponding to different types of optical fibers. The types of the optical fibers include type one, type two and type three.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber fusion splicer technology, specifically relating to an automatic focusing algorithm and a method for extracting arc feature values ​​based on the algorithm. Background Technology

[0002] A fiber optic fusion splicer is a high-tech instrument combining optics, electronics, and precision mechanics. It is primarily used for the construction and maintenance of optical cables in optical communication, hence its other name, optical cable fusion splicer. Its general working principle involves using a high-voltage electric arc to melt the cross-sections of two optical fibers while a high-precision motion mechanism smoothly advances them to fuse them into one. The spliced ​​fiber possesses low loss and high mechanical strength, thereby achieving fiber mode field coupling and enabling effective signal transmission.

[0003] Fiber optic fusion splicers generate an electric arc during fiber optic splicing, providing a direct indication of the splice quality. Since the electric arc generated during fiber optic discharge splicing directly characterizes the splice quality of the two fibers, a clearer arc allows for more accurate judgment. Therefore, before fiber optic discharge splicing, a focusing structure is needed to obtain high-quality fiber optic imaging. Furthermore, different types of fibers produce different arc shapes, requiring methods to accurately obtain characteristic values ​​based on the characteristics of various arcs. The more accurate the arc characteristic values ​​are, the more effective the automatic discharge adjustments made by the fiber optic fusion splicer will be.

[0004] However, most existing fiber optic fusion splicers cannot guarantee that the current arc imaging is in the best condition, and different fiber types use the same method to obtain arc characteristic values. Since different types of fibers produce different arc shapes, using the same method to collect characteristic values ​​of different types of fibers cannot guarantee that the characteristics of the arc can be accurately represented, which can easily reduce the effectiveness of the automatic discharge adjustment made by the fiber optic fusion splicer based on this. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of the present invention is to provide an autofocusing algorithm that changes the focal length by the slope of the fiber edge to obtain the best image of the electric arc.

[0006] An automatic focusing algorithm, applied to a fiber optic fusion splicer, includes the following steps:

[0007] The focusing motor is operated step by step within a set number of steps, and the fiber edge slope and maximum fiber edge brightness are calculated for each step during the operation.

[0008] During operation, the maximum slope of the fiber edge is obtained and the maximum brightness of the fiber edge corresponding to the number of steps of the focusing motor is stored.

[0009] Record the number of operation steps corresponding to the fiber optic compliance slope during the operation process to the edge qualified step number array. The value of the fiber optic compliance slope is the same as the maximum value of the fiber edge slope.

[0010] Obtain the maximum brightness of the fiber edge corresponding to the running step number in the edge qualified step count array;

[0011] Determine the maximum value of the maximum brightness at the edge of the optical fiber during operation. The corresponding operation step number is the final target operation step number. At this time, the focusing motor is at the target position.

[0012] To improve the quality of the fiber optic image, before the single-step focusing motor is operated, the fiber optic fusion splicer needs to automatically adjust the imaging background brightness to the set brightness, so that the focusing motor is reset to the initial state, and then place the fiber optic cable, so that the fiber optic fusion splicer can automatically advance the fiber optic cable to the designated position and align the two fibers.

[0013] Another objective of this invention is to provide a method for extracting arc feature values, which can use different methods to obtain arc feature values ​​according to different types of optical fibers.

[0014] A method for extracting arc feature values, which, after using the above-mentioned autofocus algorithm, applies different methods to obtain arc feature values ​​according to different types of optical fibers, wherein the types of optical fibers include: type one, type two and type three;

[0015] The characteristics of the fiber optic discharge arc sampling image of type one are as follows: the bright area is elliptical in shape, and the central area is the brightest. From the central area to the edge, the arc brightness gradually decreases. When the fiber optic fusion splicer discharges strongly, there is an obvious bright area in the central area. When the fiber optic fusion splicer discharges weakly, there is no bright area in the middle area.

[0016] The characteristics of the fiber optic discharge arc sampling image of type two are: the arc center is full, it spreads from the center area to the left and right sides, and there is a linear bright area at the horizontal axis of the center area.

[0017] The characteristics of the fiber optic discharge arc sampling image of type three are as follows: the bright area is concentrated in the upper half of the sampling arc image, the arc brightness gradually decreases from the center to the edge, and the brightness is different at different positions in the vertical direction when the horizontal position remains unchanged.

[0018] When the fiber optic fusion splicer discharges strongly, the average brightness of the fiber optic discharge arc sampling images of types 1, 2, and 3 is greater than the average brightness of the same type of fiber optic discharge arc sampling images when the fiber optic fusion splicer discharges weakly.

[0019] Based on the characteristics of the fiber optic discharge arc sampling image of type one, the horizontal sampling range in the sampling area of ​​type one is from the left boundary to the right boundary of the arc, and the vertical sampling range is from the upper boundary to the lower boundary of the arc.

[0020] The arc characteristic value determination process of type one includes the following steps: the determination of arc characteristic value is divided into two parts based on whether there is a bright area in the center of the arc sampling area: when there is a bright area, the arc intensity is determined based on the size of the bright area range; when there is no bright area, the arc intensity is determined based on the size of the effective arc width in the horizontal direction of the arc.

[0021] The method for determining the bright area is as follows: confirm the longitudinal center position of the electric arc, and calculate the area from the left to the right side of the imaging target surface where the pixel value is greater than a set threshold based on the longitudinal center position of the electric arc, which is the bright area.

[0022] When there is a highlighted area: if the highlighted area is greater than the set first upper threshold A, the current arc intensity is determined to be level one; if the highlighted area is less than the set first lower threshold B, the current arc intensity is determined to be level three; if the highlighted area is between the first upper threshold A and the first lower threshold B, the current arc intensity is determined to be level two.

[0023] When there is no highlighted area, if the effective arc width is greater than the second upper threshold C, the current arc intensity is determined to be level four; if the effective arc width is less than the second lower threshold D, the current arc intensity is determined to be level six; if the effective arc width is between the second upper threshold C and the second lower threshold D, the current arc intensity is determined to be level five.

[0024] Based on the characteristics of the fiber optic discharge arc sampling image of type two, the horizontal sampling range of the sampling area of ​​type two is from the left boundary to the right boundary of the arc, and the vertical sampling range is the upper half of the arc.

[0025] The arc characteristic value determination process of type two includes the following steps: determining the upper and lower boundaries of the arc in the longitudinal direction, then determining the longitudinal position coordinates and horizontal range of the arc sampling, setting the brightness threshold of the arc width, determining the left and right boundaries of the effective arc within the sampling area according to the brightness threshold of the arc width, calculating the effective arc width in the horizontal direction of the arc, and determining the arc intensity.

[0026] The calculation process for the effective arc width in the horizontal direction includes: determining the maximum arc brightness (MAX) and the minimum arc brightness (MIN) in the sampling area. Within the sampling area, the left and right boundaries of the effective arc are determined based on the brightness threshold of the arc width, thereby determining the arc width and calculating the effective arc width, where the effective arc width = arc width * brightness threshold of arc width / maximum arc brightness.

[0027] Based on the characteristics of the fiber optic discharge arc sampling image of type three, the horizontal sampling range in the sampling area of ​​type three is from the left boundary to the right boundary of the arc, and the vertical sampling range is at least one selected vertically uniformly distributed sampling partition.

[0028] The arc feature value determination process of type three includes the following steps: determining the upper and lower boundaries of the arc in the longitudinal direction, setting at least one sampling partition and distributing it evenly within the longitudinal sampling range of the arc, then determining the horizontal coordinates corresponding to the maximum brightness in the horizontal direction of the arc, thereby determining the center position of the arc in the horizontal direction, and using it as the sampling center in the horizontal direction. After confirming the horizontal sampling range, calculating the pixel average value of the arc in the sampling partition, and determining the feature brightness value of the arc based on the mean of the pixel average values, and determining the arc intensity based on the feature brightness value.

[0029] The electric arc intensity includes six levels, which are ranked from highest to lowest as level one to level six.

[0030] The beneficial effects of this invention are: the automatic focusing algorithm can adjust the focal length of the focusing motor in the fiber optic fusion splicer according to the fiber slope, so that the image of the sampled arc is in the best quality state, providing a clear image basis for the extraction of fusion arc feature values.

[0031] This method for extracting arc feature values, after obtaining a clear arc sampling image through an autofocus algorithm, can apply different methods to obtain arc feature values ​​according to the different characteristics of the arc generated during fusion splicing of different types of optical fibers. This can effectively improve the effectiveness and accuracy of the automatic discharge adjustment made by the optical fiber fusion splicer based on the feature values, and help improve the judgment of fusion quality. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0033] Figure 1 This is a flowchart of the automatic focusing process of the present invention;

[0034] Figure 2 This is the arc characteristic curve of the optical fiber G.651 of this invention at the discharge intensity;

[0035] Figure 3 This is the arc characteristic curve of the optical fiber G.651 of this invention when the discharge is weak;

[0036] Figure 4 This is the arc characteristic curve of the optical fiber G.655 of the present invention at the discharge intensity;

[0037] Figure 5This is the arc characteristic curve of the optical fiber G.655 when the discharge is weak according to the present invention;

[0038] Figure 6 This is a flowchart of the arc characteristic value determination method used in optical fiber type one of the present invention;

[0039] Figure 7 This is the arc characteristic curve of the optical fiber G.652 of this invention at the discharge intensity;

[0040] Figure 8 This is the arc characteristic curve of the optical fiber G.652 of the present invention when the discharge is weak;

[0041] Figure 9 This is a flowchart of the arc characteristic value determination method used in optical fiber type two of this invention;

[0042] Figure 10 This is the arc characteristic curve of the optical fiber G.654 of the present invention at the discharge intensity;

[0043] Figure 11 This is the arc characteristic curve of the optical fiber G.654 of the present invention when the discharge is weak;

[0044] Figure 12 This is a flowchart of the arc characteristic value determination method used in the third type of optical fiber of the present invention;

[0045] Figure 13 This is a schematic diagram of the focusing module in the optical fiber fusion splicer of the present invention;

[0046] Figure 14 This is a schematic diagram of the working function of the focusing module of the present invention;

[0047] Figure 15 This is a schematic diagram of fiber optic blur imaging;

[0048] Figure 16 This is a schematic diagram of clear fiber optic imaging;

[0049] Figure 17 This is a schematic diagram of discharge arc imaging during fiber optic blur imaging;

[0050] Figure 18 This is a schematic diagram of discharge arc imaging during clear fiber optic imaging.

[0051] The following are labeled in the diagram: 1. Imaging lens; 2. Focusing motor; 3. Image sensor; 4. X image sensor; 5. Y image sensor. Detailed Implementation

[0052] like Figure 13 As shown, the focusing module used in the fiber optic fusion splicer includes an imaging lens 1, a focusing motor 2, and an image sensor 3. The image sensor 3 and the imaging lens 1 are used for acquiring fiber optic images, and the focusing motor 2 is used for adjusting the imaging focal length.

[0053] like Figure 14 As shown, in practical applications, the fiber optic fusion splicer includes two image acquisition channels formed by an X image sensor 4 and a Y image sensor 5, with an imaging angle of 90 degrees. This invention uses one of the images as the determination source image, and adjusts the imaging focal length by driving the focusing motor 2 to change the distance between the imaging lens 1 and the image sensor 3, thereby realizing the imaging change of the fiber.

[0054] Example 1

[0055] like Figures 15 to 18 As shown, taking fiber type 2 as an example, the clarity of the sampled fiber image and the sampled arc image will affect the magnitude of the arc longitudinal feature value. Therefore, by adjusting the imaging focal length through the focusing module to improve image clarity, the accuracy of the sampled arc longitudinal feature value can be effectively improved.

[0056] like Figure 1 As shown, this invention provides an automatic focusing algorithm applied to a fiber optic fusion splicer, comprising the following steps:

[0057] The focusing motor is operated step by step within a set number of steps, and the fiber edge slope and maximum fiber edge brightness are calculated for each step during the operation.

[0058] During operation, the maximum slope of the fiber edge is obtained and the maximum brightness of the fiber edge corresponding to the number of steps of the focusing motor is stored.

[0059] Record the number of operation steps corresponding to the fiber optic compliance slope during the operation process to the edge qualified step number array. The value of the fiber optic compliance slope is the same as the maximum value of the fiber edge slope.

[0060] Obtain the maximum brightness of the fiber edge corresponding to the running step number in the edge qualified step count array;

[0061] Determine the maximum value of the maximum brightness at the edge of the optical fiber during operation. The corresponding operation step number is the final target operation step number. At this time, the focusing motor is at the target position.

[0062] To improve the clarity of fiber optic imaging, the fiber optic fusion splicer needs to automatically adjust the imaging background brightness to the set brightness before the single-step focusing motor is turned on, so that the fiber optic sampled image can be clearly displayed. This brightness threshold can be set in advance to reset the focusing motor to the initial state. Then the fiber is placed, and the fiber optic fusion splicer automatically pushes the fiber to the designated position and aligns the two fibers.

[0063] By calculating the slope of the fiber edge, the operating step number corresponding to the maximum slope of the fiber edge is found. Since there may be more than one operating step number corresponding to the maximum slope of the fiber edge, and each operating step number corresponds to a maximum brightness of the fiber edge, by comparing and determining the maximum value among the maximum brightness of the fiber edge corresponding to several operating step numbers, the corresponding operating step number can be determined as the target operating step number. When the focusing motor runs to the target operating step number, it is at the target position, that is, when the slope of the fiber edge is the maximum and the maximum brightness of the fiber edge is the maximum, the image of the sampled arc is in the best quality state.

[0064] Example 2

[0065] A second aspect of the present invention provides a method for extracting arc feature values, applied to an optical fiber fusion splicer. The method is characterized by using the autofocus algorithm described in Example 1, and then applying different methods to obtain the arc feature values ​​according to different types of optical fibers. The types of optical fibers include: Type 1, Type 2, and Type 3. The arc intensity is determined based on the arc feature values ​​to characterize the current discharge state. The arc intensity includes six levels, from highest to lowest: Level 1 to Level 6. By pre-setting level thresholds, the method can determine the corresponding arc intensity based on the size of the bright area and the width of the effective arc.

[0066] like Figures 2 to 5 As shown, Type 1 can include fiber G.651 and fiber G.655. The characteristics of the fiber discharge arc sampling image of Type 1 are: the bright area is elliptical in the horizontal direction, and the central area is the brightest. From the central area to the edge, the arc brightness gradually decreases. When the fiber fusion splicer discharges strongly, there is an obvious bright area in the central area. When the fiber fusion splicer discharges weakly, there is no bright area in the middle area.

[0067] like Figure 6 As shown, based on the characteristics of fiber optic discharge arc imaging of type 1, the horizontal sampling range in the sampling area of ​​type 1 is from the left boundary to the right boundary of the arc, and the vertical sampling range is from the upper boundary to the lower boundary of the arc.

[0068] The process for determining the arc characteristic value of type 1 includes the following steps: The determination of the arc characteristic value is divided into two parts based on whether there is a bright area in the center of the arc sampling area: when there is a bright area, the arc intensity is determined based on the size of the bright area; when there is no bright area, the arc intensity is determined based on the size of the effective arc width in the horizontal direction.

[0069] The method for determining the bright areas is as follows: The longitudinal center position of the electric arc is confirmed, and based on this position, the area from the left to the right of the imaging target surface with a pixel value greater than a set threshold is calculated; this area is considered the bright area. Since the pixel value in this invention is 8 bits wide with a maximum value of 255, the threshold is set to 250. Therefore, areas with a pixel value greater than 250 are considered bright areas.

[0070] Specifically, when there is a highlighted area: if the highlighted area is greater than the set first upper threshold A, the current arc intensity is determined to be level one; if the highlighted area is less than the set first lower threshold B, the current arc intensity is determined to be level three; if the highlighted area is between the first upper threshold A and the first lower threshold B, the current arc intensity is determined to be level two.

[0071] When there is no highlighted area, if the effective arc width is greater than the second upper threshold C, the current arc intensity is determined to be level four; if the effective arc width is less than the second lower threshold D, the current arc intensity is determined to be level six; if the effective arc width is between the second upper threshold C and the second lower threshold D, the current arc intensity is determined to be level five.

[0072] The calculation process for the effective arc width in the horizontal direction includes: determining the maximum arc brightness (MAX) and minimum arc brightness (MIN) in the sampling area. Within the sampling area, the left and right boundaries of the effective arc are determined based on the brightness threshold of the arc width, thereby determining the arc width and calculating the effective arc width, where: effective arc width = arc width * brightness threshold of arc width / maximum arc brightness. Since the pixel value in this invention is 8 bits wide with a maximum value of 255, the maximum arc brightness is 255.

[0073] The process for confirming the arc width is as follows: Starting from the horizontal sampling start position of the arc and moving to the right, when the arc brightness exceeds the brightness threshold of the arc width, the horizontal coordinate at this point is the left boundary of the arc; starting from the horizontal sampling end position of the arc and moving to the left, when the arc brightness exceeds the brightness threshold of the arc width, the horizontal coordinate at this point is the right boundary of the arc, and the distance between the left and right boundaries of the arc is the arc width.

[0074] like Figures 7 to 8 As shown, type two may include optical fiber G.652. The characteristics of the optical fiber discharge arc sampling image of type two are: the arc center is full, and it spreads from the central region to the left and right sides. There is a linear bright area at the transverse axis of the central region.

[0075] like Figure 9 As shown, based on the characteristics of fiber optic discharge arc imaging of type 2, the horizontal sampling range in the sampling area of ​​type 2 is from the left boundary to the right boundary of the arc, and the vertical sampling range is the upper half of the arc.

[0076] The process for determining the arc characteristic value of type two includes the following steps: determining the upper and lower boundaries of the arc in the longitudinal direction, then determining the longitudinal position coordinates and horizontal range of the arc sampling, setting the brightness threshold of the arc width, determining the left and right boundaries of the effective arc within the sampling area based on the brightness threshold of the arc width, calculating the effective arc width in the horizontal direction, and determining the arc intensity. The calculation of the effective arc width in the horizontal direction is the same as the above calculation process for the effective arc width in the horizontal direction.

[0077] like Figures 10 to 11 As shown, type three may include optical fiber G.654. ​​The characteristics of the optical fiber discharge arc sampling image of type three are: the bright area is concentrated in the upper half of the sampling arc image, the arc brightness gradually decreases from the center to the edge, and the brightness is different at different positions in the vertical direction when the horizontal position remains unchanged.

[0078] like Figure 12 As shown, based on the characteristics of fiber optic discharge arc imaging of type 3, the horizontal sampling range in the sampling area of ​​type 3 is from the left boundary to the right boundary of the arc, and the vertical sampling range is at least one selected vertically uniformly distributed sampling partition.

[0079] The process for determining the arc characteristic value of type 3 includes the following steps: determining the upper and lower boundaries of the arc in the longitudinal direction, setting at least one sampling partition and distributing it evenly within the longitudinal sampling range of the arc, determining the horizontal coordinates corresponding to the maximum brightness in the horizontal direction of the arc, thereby determining the center position of the arc in the horizontal direction, and using it as the sampling center in the horizontal direction. After confirming the horizontal sampling range, calculating the pixel average value of the arc in the sampling partition, and determining the characteristic brightness value of the arc based on the mean of the pixel average values, and determining the arc intensity based on the characteristic brightness value.

[0080] like Figures 2 to 5 , Figures 7 to 8 , Figures 10 to 11 As shown, when the fiber optic fusion splicer discharges strongly, the average brightness of the fiber optic discharge arc sampling images of types 1, 2, and 3 is greater than the average brightness of the same type of fiber optic discharge arc sampling images when the fiber optic fusion splicer discharges weakly.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An arc characteristic value extraction method based on an automatic focusing algorithm, applied to an optical fiber fusion splicer, characterized in that, The method comprises the following steps: Single-step operation of the focusing motor is performed within a set step range, and the fiber edge slope and the maximum fiber edge brightness at each step during the operation are calculated; During the operation, the maximum fiber edge slope is obtained, and the maximum fiber edge brightness corresponding to the step number of the focusing motor at this time is stored; The step number corresponding to the qualified fiber edge slope during the operation is recorded to the edge qualified step number array, and the value of the qualified fiber edge slope is the same as the maximum fiber edge slope; The maximum fiber edge brightness corresponding to the step number in the edge qualified step number array is obtained; The maximum value in the maximum fiber edge brightness during the operation is determined, and the step number corresponding to the maximum value is the final target step number, at this time, the focusing motor is at the target position; According to the characteristics of the fiber discharge arc sampling image, the sampling range is determined and the arc characteristic value is determined, and the process is as follows: The characteristics of the fiber discharge arc sampling image are that the bright area is in the shape of a horizontal ellipse, and the center area is the brightest, the arc brightness gradually weakens from the center area to the edge, when the discharge of the fiber fusion machine is strong, there is a obvious highlight area in the center area, when the discharge of the fiber fusion machine is weak, there is no highlight area in the center area; the horizontal sampling range in the sampling area is the left boundary to the right boundary of the arc, and the vertical sampling range is the upper boundary to the lower boundary of the arc; The determination process comprises the following steps: according to whether there is a highlight area in the center of the arc sampling area, the determination of the arc characteristic value is divided into two parts: when there is a highlight area, the arc intensity is determined according to the size of the highlight area range, and when there is no highlight area, the arc intensity is determined according to the effective arc width in the horizontal direction of the arc.

2. The method of claim 1, wherein the method is based on an auto-focusing algorithm. The determination method of the highlight area is: confirming the vertical center position of the arc, and calculating the area with a pixel value greater than a set threshold from the left side to the right side of the imaging target surface based on the vertical center position of the arc, that is, the highlight area.

3. The method of claim 1, wherein the method further comprises: When there is a highlight area: if the highlight area is greater than a set first upper threshold A, it is determined that the current arc intensity is level one; if the highlight area is less than a set first lower threshold B, it is determined that the current arc intensity is level three; if the highlight area is between the first upper threshold A and the first lower threshold B, it is determined that the current arc intensity is level two; When there is no highlight area, if the effective arc width is greater than a second upper threshold C, it is determined that the current arc intensity is level four; if the effective arc width is less than a second lower threshold D, it is determined that the current arc intensity is level six; if the effective arc width is between the second upper threshold C and the second lower threshold D, it is determined that the current arc intensity is level five.

4. An arc characteristic value extraction method based on an automatic focusing algorithm, applied to an optical fiber fusion splicer, characterized in that, The method comprises the following steps: Single-step operation of the focusing motor is performed within a set step range, and the fiber edge slope and the maximum fiber edge brightness at each step during the operation are calculated; During the operation, the maximum fiber edge slope is obtained, and the maximum fiber edge brightness corresponding to the step number of the focusing motor at this time is stored; The step number corresponding to the qualified fiber edge slope during the operation is recorded to the edge qualified step number array, and the value of the qualified fiber edge slope is the same as the maximum fiber edge slope; The maximum fiber edge brightness corresponding to the step number in the edge qualified step number array is obtained; Determine the maximum value in the maximum brightness of the fiber edge during operation, and the corresponding operation step number is the final target operation step number, at this time, the focusing motor is at the target position; According to the characteristics of the optical fiber discharge arc sampling image, the sampling range is determined and the arc characteristic value is judged, and the process is as follows: The characteristics of the optical fiber discharge arc sampling image are that the arc center is full, spreading from the center area to the left and right sides, and there is a linear bright area at the horizontal axis of the center area; the horizontal sampling range in the sampling area is the left boundary to the right boundary of the arc, and the vertical sampling range is the upper half area of the arc; The judgment process includes the following steps: determining the upper boundary and the lower boundary of the arc in the vertical direction, then determining the vertical position coordinate and the horizontal range of the arc sampling, setting the brightness threshold of the arc width, determining the left boundary and the right boundary of the effective arc in the sampling area according to the brightness threshold of the arc width, calculating the effective arc width in the horizontal direction of the arc, and judging the arc intensity.

5. The method according to claim 1 or 4, wherein, The calculation process of the effective arc width in the horizontal direction of the arc includes: determining the maximum arc brightness MAX and the minimum arc brightness MIN in the sampling area, setting the brightness threshold of the arc width determining the left boundary and the right boundary of the arc according to the brightness threshold of the arc width in the sampling area, thereby determining the arc width, and calculating the effective arc width, wherein the effective arc width = arc width The brightness threshold of the arc width / the maximum arc brightness.

6. An arc characteristic value extraction method based on an automatic focusing algorithm, applied to an optical fiber fusion splicer, characterized in that, The method comprises the following steps: Single-step operation of the focusing motor is performed within a set step range, and the fiber edge slope and the maximum brightness of the fiber edge at each step during operation are calculated; During the operation, the maximum value of the fiber edge slope is obtained, and the maximum brightness of the fiber edge corresponding to the focusing motor operation step number at this time is stored; The operation step number corresponding to the qualified fiber edge slope in the operation stroke is recorded to the edge qualified step number array, and the value of the qualified fiber edge slope is the same as the maximum value of the fiber edge slope; The maximum brightness of the fiber edge corresponding to the operation step number in the edge qualified step number array is obtained; Determine the maximum value in the maximum brightness of the fiber edge during operation, and the corresponding operation step number is the final target operation step number, at this time, the focusing motor is at the target position; According to the characteristics of the optical fiber discharge arc sampling image, the sampling range is determined and the arc characteristic value is judged, and the process is as follows: The characteristics of the optical fiber discharge arc sampling image are that the bright area is concentrated in the upper half area of the sampling arc image, the arc brightness gradually weakens from the center area to the edge, and when the horizontal position is unchanged, the brightness is different at different vertical positions; the horizontal sampling range in the sampling area is the left boundary to the right boundary of the arc, and the vertical sampling range is at least one sampling subzone uniformly distributed in the vertical sampling range of the arc; The arc characteristic value judgment process includes the following steps: determining the upper boundary and the lower boundary of the arc in the vertical direction, setting at least one sampling subzone and uniformly distributing it in the vertical sampling range of the arc, then determining the horizontal coordinate corresponding to the maximum brightness of the arc in the horizontal direction, so as to determine the center position of the arc in the horizontal direction and as the sampling center in the horizontal direction, after confirming the horizontal sampling range, calculating the pixel average value of the arc in the sampling subzone, and determining the characteristic brightness value of the arc according to the average value of each pixel average value, and judging the arc intensity according to the characteristic brightness value.

7. The method according to claim 1 or 4 or 6, wherein, Before the single-step operation of the focusing motor, the optical fiber fusion machine needs to automatically adjust the imaging background brightness to the set brightness, reset the focusing motor to the initial state, and then place the optical fiber, so that the optical fiber fusion machine automatically advances the optical fiber to the specified position and aligns the two sides of the optical fiber.

8. The method according to claim 1 or 4 or 6, wherein, The average brightness of the sampling image of the optical fiber discharge arc is greater than the average brightness of the sampling image of the same type of optical fiber discharge arc when the discharge of the optical fiber fusion splicer is weak.

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