Fusion machine

Abstract

To provide a fusion machine capable of accurately grasping an end face position of a coated optical fiber, even when light leaks.SOLUTION: An image processing part can perform various processing to an image captured by an imaging part. Focus adjustment can be automatically performed by for example, operating a conveyance drive part or the like by a control part and changing an optical path (distance or the like) from an end face of a coated optical fiber to the imaging part. The control part moves a holder placing part or the imaging part, to capture at least two different captured images 35a and 35b by the imaging part. The image processing part compares the plurality of obtained captured images 35a and 35b, to obtain a difference and extracts only a part where the difference is equal to or more than a predetermined value, to create a difference image 41a.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fusion splicer that is excellent in alignment workability. [Background technology]

[0002] A fusion splicer is used to connect optical fibers together. The fusion splicer places optical fibers held in a pair of holders, butts them together, places them between electrodes, and fuses the tips of the optical fibers together using an arc, thereby connecting the optical fibers together.

[0003] When fusing optical fibers together, alignment work is required to align the tip positions of the optical fibers. For this reason, conventionally, alignment was performed by placing the optical fibers opposite each other and capturing an image of the tip positions of the optical fibers from the side (perpendicular to the axial direction of the optical fibers) using an imaging unit.

[0004] On the other hand, when an optical fiber is not a typical single-core optical fiber but has a circumferential direction relative to its cross-sectional shape, such as a polarization-maintaining fiber or a multi-core fiber, alignment is required not only in the tip position but also in the rotational direction. In other words, not only alignment in the so-called XY directions at the tip position of the optical fiber but also rotational alignment in the circumferential direction around the axial direction of the optical fiber is required.

[0005] To perform such rotational alignment of an optical fiber, for example, a reflective member is placed between the opposing optical fibers, the end face of the optical fiber is reflected by an imaging unit to be imaged, and rotational alignment is performed by observing the end face (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-53625 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method of Patent Document 1 uses epi-illumination, which means that light is irradiated onto the end face of the optical fiber and the reflected light is checked, which results in a complex structure due to the use of a half mirror or the like.

[0008] In contrast, there is a method in which light is incident on the end face of the optical fiber opposite to the observation end face. With this method, light passes through the optical fiber (core) and exits toward the observation end face, so the core appears uniformly bright on the observation surface. This makes it possible to reliably determine the core arrangement and the positions of the stress-applying parts (hereinafter simply referred to as core arrangement, etc.).

[0009] However, if the optical fiber to be connected is already connected to other equipment, it may be difficult to freely input light from the end face. In such cases, a method of inputting light from the side of the optical fiber can be considered. A portion of the light input from the side of the optical fiber propagates within the optical fiber and is output from the end face. This makes it possible to check the core arrangement, etc., at the end face of the optical fiber.

[0010] 8(a) is a conceptual diagram of a captured image 100 obtained by irradiating light from the side of an optical fiber. Fiber image 101a and fiber image 101b, which are images of the end faces of a pair of coated optical fibers, are captured. In this case, for example, fiber image 101a and fiber image 101b are superimposed to obtain a composite image, and alignment can be performed by rotating the coated optical fiber so that both images are completely superimposed.

[0011] To obtain such a composite image, it is first necessary to identify the center points of each fiber image 101a, 101b and perform image processing to align the positions of the center points. One method for obtaining the center points of fiber images 101a, 101b is to binarize fiber images 101a and 101b, identify the outer edges of the circles in fiber images 101a and 101b, and then perform image analysis of each of the obtained circles to identify their center points.

[0012] However, if light is irradiated from the side of the optical fiber, some of the light may enter the imaging device. Figure 8(b) is a conceptual diagram showing a state in which leakage light 103 is captured in a captured image. When light is captured in the background in this way, the boundary between the optical fiber and the background becomes unclear.

[0013] Fig. 8(c) is a conceptual diagram of the binarization of Fig. 8(b). As shown in Fig. 8(c), when binarized, part of the background also appears white, whereas only the cladding of the optical fiber core is originally displayed in white. This makes it impossible to accurately grasp the circles that form the outer edges of fiber image 101a and fiber image 101b through image processing. This makes it difficult to identify the center positions of fiber image 101a and fiber image 101b, which makes the alignment work difficult or reduces accuracy.

[0014] The present invention has been made in consideration of such problems, and aims to provide a fusion splicer that can accurately grasp the end face position of an optical fiber core even when there is light leakage. [Means for solving the problem]

[0015] In order to achieve the above-mentioned object, the present invention provides a fusion splicer for connecting a pair of optical fiber core wires, comprising a pair of holder mounting sections on which holders for holding the optical fiber core wires are mounted, a light source capable of irradiating light from the side of the optical fiber core wire mounted on the holder mounting section, a reflective member that can move between the pair of holder mounting sections, an imaging section that captures the image reflected by the reflective member, an image processing section that processes the image captured by the imaging section, and a control section that can adjust the focus by changing the optical path from the end face of the optical fiber core wire to the imaging section, wherein the control section moves the holder mounting section or the imaging section to capture at least two different images with the imaging section, and the image processing section is capable of comparing the multiple images obtained, taking the difference, and extracting only the parts where the difference is greater than a predetermined value to create a difference image.

[0016] One of the images captured by the imaging unit is a reference image focused on the end face of the optical fiber core, and the control unit may identify the center position of the optical fiber core from the difference image and set this center position as the center position of the optical fiber core in the reference image.

[0017] The image processing unit may create a composite image by overlapping the reference images obtained for the respective optical fiber cores with their respective centers aligned.

[0018] The device may be provided with a rotational drive unit that can rotate at least one of the holder mounting parts around an axis in the opposing direction of the pair of holder mounting parts, thereby rotationally aligning a pair of optical fiber cores, and may be capable of rotationally aligning the optical fiber using the composite image.

[0019] The control unit may be capable of capturing two different images with the imaging unit by moving the holder placement units in opposing directions of the pair of holder placement units.

[0020] According to the present invention, a fiber image, which is an image of the end face of an optical fiber core, can be captured at different focal points and the difference between the two images can be calculated to obtain a fiber image from which the influence of the background has been removed. Therefore, even if there is light leakage in the background, the influence of the light leakage can be eliminated, and only the fiber image can be extracted to identify the position of the optical fiber core (fiber image) in the captured image.

[0021] Furthermore, by using a reference image focused on the end face position of the optical fiber as one of the images from which the difference is taken, the center position of the optical fiber can be identified with higher accuracy.

[0022] Furthermore, the image processing unit can create a composite image by aligning the center positions of the reference images obtained for the respective optical fiber cores and superimposing them together, thereby enabling the alignment work to be performed with high precision.

[0023] Furthermore, by rotating at least one of the holder mounting parts about an axis in the opposing direction of the pair of holder mounting parts, it is possible to rotationally align the pair of optical fibers with each other.

[0024] Furthermore, by moving the holder placement parts in the opposing direction of the pair of holder placement parts and capturing two different images with the imaging parts, it is possible to easily obtain images with different focal points. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a fusion splicer that can accurately grasp the position of the end face of an optical fiber even when there is light leakage. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a perspective view showing a fusion splicer 1. [Figure 2] FIG. 2 is a schematic diagram showing the internal configuration of the fusion splicer 1. [Figure 3] FIG. 1 is a block diagram showing the configuration of a fusion splicer 1. [Figure 4] FIG. 2 is a schematic diagram showing the internal configuration of the fusion splicer 1 in use. [Figure 5] 1A is a conceptual diagram showing a captured image 35a, FIG. 1B is a conceptual diagram showing a captured image 35b, and FIG. 1C is a conceptual diagram showing a differential image 41a. [Figure 6] (a) is a conceptual diagram showing the difference image 41b, (b) is a conceptual diagram showing the state in which center points 43a and 43b have been identified in the difference image 41b, and (c) is a conceptual diagram showing the state in which center points 43a and 43b have been synthesized with the captured image 35a. [Figure 7] 4(a) and 4(b) are conceptual diagrams showing a composite image 45. FIG. [Figure 8] 1A and 1B are conceptual diagrams showing a conventional captured image 100, and 1C is a conceptual diagram showing a binarized image 105 obtained from the captured image 100 in 1C. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing a fusion splicer 1, and Fig. 2(a) is a schematic diagram showing the arrangement of each component in a main body 9. The fusion splicer 1 connects a pair of optical fiber cores by fusion. Note that in the following figures, components not necessary for the explanation are omitted.

[0028] 1, the fusion splicer 1 has a windshield 3 that can be opened and closed relative to a main body 9. The main body 9 also has a holder placement section 11 on which a holder that holds an optical fiber is placed, a V-groove 5 in which the optical fiber is positioned, an operation section 15 for performing various settings of the fusion splicer 1 and an alignment operation and fusion operation, which will be described later, and a display section 17 for displaying various information and images. The operation section 15 and the display section 17 may be integrated by using a touch panel as the display section 17.

[0029] As shown in FIG. 2(a), a pair of holder mounting portions 11 are arranged facing each other on the main body 9, and a V-shaped groove 5 and an electrode 7 are arranged in this order from the holder mounting portion 11 in the facing direction. The holder mounting portion 11 is fixed to a rotation drive unit 19 and a transport drive unit 31. The transport drive unit 31 can move the holder mounting portion 11 in the facing direction of the holder mounting portion 11 (left and right direction in FIG. 2(a)). In other words, the distance between the optical fiber core and the electrode 7 can be adjusted. Furthermore, the rotation drive unit 19 can rotate the holder mounting portion 11 around the facing direction of the holder mounting portion 11 (left and right direction in FIG. 2(a)) as the rotation axis. In other words, rotational alignment of the optical fiber core can be performed.

[0030] Furthermore, V-grooves 5 for holding the optical fiber exposed from the tip of each holder are arranged on the opposing sides (i.e., electrode 7 sides) of the pair of holder mounting parts 11. By placing the optical fiber in the V-groove 5 during fusion splicing, the optical fiber can be positioned.

[0031] At this time, a clamp 13 (see FIG. 1) is provided on the back surface of the windshield 3, and when the windshield 3 is closed, the tip of the clamp 13 is located at a position corresponding to the position of the optical fiber on the V-groove 5. In other words, the pair of optical fiber cores can be held facing each other in the V-groove 5 by the clamp 13 provided on the back surface of the windshield 3.

[0032] Furthermore, a pair of electrodes 7 are arranged facing each other in a direction approximately perpendicular to the facing direction of the pair of coated optical fibers. With the windshield 3 closed and the tips of the coated optical fibers butted together, an arc is generated between the pair of electrodes 7, thereby melting and joining the tips of the coated optical fibers.

[0033] Furthermore, a reflective member 21 is disposed between the pair of electrodes 7. The reflective member 21 can move up and down, and is retracted from between the electrodes 7 during fusion bonding, and can be raised and disposed between the electrodes 7 during the alignment work described below. That is, FIG. 2(a) shows the reflective member 21 in a raised state, and the reflective member 21 is movably disposed between the pair of holder placement portions 11.

[0034] Each light source 23a is disposed on the opposing side (electrode 7 side) of the pair of holder mounting parts 11 relative to the holder mounting parts 11. More specifically, each light source 23a is disposed between the V-groove 5 and the holder mounting part 11. Furthermore, each light source 23b is disposed on the rear side of the pair of holder mounting parts 11 (opposite the opposing side of the pair of holder mounting parts 11). The light sources 23a and 23b can irradiate light from the sides of the respective optical fiber cores.

[0035] Next, we will explain the configuration of the fusion splicer 1. As shown in Fig. 3, the fusion splicer 1 is composed of an imaging unit 25, a rotation drive unit 19, a transport drive unit 31, an image processing unit 33, an operation unit 15, a display unit 17, and a control unit 30 that controls these units and performs calculations. Note that components such as discharge control that are not necessary for explaining this embodiment will be omitted.

[0036] The operation unit 15 can input various control details and setting conditions to be performed by the control unit 30. For example, the operation unit 15 can select either or both of the light sources 23a and 23b described above to irradiate light onto the optical fiber core. Depending on the size and type of the optical fiber core, the appearance at the end face will differ even if the same light is introduced. For this reason, by comparing the case where light is introduced from the light source 23a and the case where light is introduced from the light source 23b, and selecting and using the one that allows a clearer view of the end face, more accurate rotational alignment can be performed.

[0037] Furthermore, the image processing unit 33 is capable of performing various processes on the image captured by the imaging unit 25. Details of the image processing by the image processing unit 33 will be described later. The display unit 17 can display the image captured by the imaging unit 25 and processed by the image processing unit 33, as well as information such as the fusion conditions.

[0038] As described above, the rotation drive unit 19 can align the pair of optical fiber core wires by rotating at least one of the pair of optical fiber core wires around an axis in the opposing direction of the pair of optical fiber core wires. The transport drive unit 31 can transport each optical fiber core wire individually in the axial direction of the optical fiber core wire. Note that the XY direction alignment of the optical fiber core wires can be performed by an alignment drive unit (not shown). Note that each drive unit is operated by, for example, a motor or the like.

[0039] Next, a method for aligning an optical fiber core will be described. Fig. 4 is a schematic diagram showing the state when aligning. Note that Fig. 4 only shows the configuration on one side of the holder mounting portion 11, but the other side will be described as symmetrical. An optical fiber core 29 is held by a pair of holders 27, and each holder 27 is mounted on the holder mounting portion 11. The optical fiber core 29 is configured by coating the outer periphery of a glass fiber 29a with a resin coating 29b. At this time, the resin coating 29b of the optical fiber core 29 exposed at the tip side of the holder 27 is removed, exposing the glass fiber 29a.

[0040] As mentioned above, the vicinity of the tip of the optical fiber core 29 (glass fiber 29a) is held in the V-groove 5, and the optical fiber core 29 is held facing each other in the V-groove 5 and positioned by the clamp 13 provided on the back surface of the windshield 3.

[0041] A reflecting member 21 is disposed between the pair of coated optical fibers 29. The reflecting member 21 has a reflecting surface on each side of the coated optical fibers 29, and is capable of reflecting an image of the tip of each coated optical fiber 29 in a 90-degree direction (upward in the figure). An imaging unit 25 is also built in between the clamps 13 of the windshield 3, and is positioned so that it can capture an image of the vicinity of the tip of the pair of optical fibers 29 when the windshield 3 is closed. In other words, the imaging unit 25 can capture an image reflected by the reflecting member 21.

[0042] As described above, the light sources 23a are disposed between the V-groove 5 and the holder mounting portion 11. The glass fiber 29a of the optical fiber 29 is exposed between the holder 27 and the V-groove 5. Therefore, the light sources 23a can irradiate light from the side onto the glass fiber 29a from which the resin coating 29b of the optical fiber 29 has been peeled off. The light sources 23b are disposed behind the holder mounting portion 11. Because the resin coating 29b of the optical fiber 29 is located behind the holder 27, the light sources 23b can irradiate light from the side onto the resin coating 29b.

[0043] A portion of the light introduced from the side of the optical fiber 29 is guided through the core or clad and emitted to the end face of the optical fiber 29. The imaging unit 25 captures an image of the end face of the optical fiber 29 using the reflecting member 21. The control unit 30 processes the image in the image processing unit 33 and displays it on the display unit 17, making it possible to grasp the core arrangement of the optical fiber 29, etc. The image processing method in the image processing unit 33 will be described later.

[0044] In this state, the rotation drive unit 19 is operated by operating the operation unit 15, etc. The rotation drive unit 19 rotates at least one of the optical fiber cores 29 held by the pair of holder mounting units 11 around an axis in the opposing direction of the pair of holder mounting units 11, thereby enabling rotational alignment of the pair of optical fiber cores 29. Details of rotational alignment will be described later.

[0045] The alignment of the tip position (X and Y directions) of the optical fiber core 29 can be performed by a conventional method. For example, another pair of imaging devices is placed in different directions on the sides of the optical fiber core 29, and images of the tip position of the optical fiber core 29 are captured from each direction and displayed on the display unit 17. The operation unit 15 is used to operate the positions and orientations of the V-groove 5 and the holder placement unit 11 so that the positions of the optical fiber cores 29 are aligned, and by aligning the X and Y positions with each other, the optical fiber core 29 can be aligned in the X and Y directions.

[0046] In this way, after XY alignment and rotational alignment of a pair of optical fiber core wires 29, the reflecting member 21 is retracted (lowered), the ends of the optical fiber core wires 29 are butted together, and an arc is generated between the electrodes 7, thereby fusing the optical fiber core wires 29 together.

[0047] Next, an image processing method in this embodiment will be described. As described above, when an end face image of the optical fiber core 29 is captured, light from the light source 23a or the like may leak through gaps in the V-groove 5 or the like and be captured in the imaging unit 25. Fig. 5(a) is a conceptual diagram showing a captured image 35a, which is an end face image of a pair of optical fiber cores 29, in which fiber images 37a and 37b are captured. Note that, although an example of polarization-maintaining fiber is shown as the fiber images 37a and 37b, other optical fibers such as multi-core fiber may also be used.

[0048] The captured image 35a is an image focused on the end face of the optical fiber 29. This focused captured image 35a may be referred to as the "reference image." Focus adjustment can be performed automatically, for example, by operating the conveyance drive unit 31 or the like using the control unit 30 to change the optical path (distance) from the end face of the optical fiber 29 to the imaging unit 25. Here, a light leakage portion 39 appears in the captured image 35a. For this reason, if binarization processing is performed as is, it becomes difficult to distinguish between the fiber images 37a and 37b and the background, as shown in Figure 8(c), and the end face of the optical fiber 29 cannot be accurately identified.

[0049] Therefore, the control unit 30 causes the conveyance drive unit 31 to move the pair of holder placement units 11 parallel to each other in the opposing directions. By doing so, the optical path length from the end face of the optical fiber 29 to the imaging unit 25 changes, and the focus that was on the end face of the optical fiber 29 shifts. In other words, the fiber image is intentionally made to blur from a focused state. Note that if the focus can be changed, the imaging unit 25 may be moved up and down instead of moving the holder placement unit 11.

[0050] 5(b) is a conceptual diagram of a captured image 35b captured by the imaging unit 25 in a blurred state of the end face of the optical fiber 29. That is, the control unit 30 moves the holder mounting unit 11 or the imaging unit 25 to capture at least two different captured images 35a and 35b with the imaging unit 25. Note that in this embodiment, of the two images captured by the imaging unit 25, one captured image 35a is a reference image focused on the end face of the optical fiber 29, but both images may be out of focus.

[0051] In the captured images 35a and 35b, only the focus of the end face of the optical fiber 29 changes. That is, the positions of the fiber images 37a and 37b do not change. Also, the light leakage part 39 and the like on the back surface other than the end face of the optical fiber 29 do not change.

[0052] 5(c), the image processing unit 33 next compares the obtained multiple captured images 35a, 35b to find the difference, and extracts only parts where the difference is greater than or equal to a predetermined value to create a difference image 41a. For example, the image processing unit 33 acquires brightness information for each pixel in the captured images 35a, 35b, and changes the brightness according to the difference by coloring parts where the difference in brightness between the two images is greater than or equal to a predetermined value white and parts where the difference is zero black to create the difference image 41a.

[0053] As described above, in the captured images 35a and 35b, only the fiber images 37a and 37b change due to a change in focus, while the background remains unchanged, resulting in a black background. Meanwhile, the brightness of the fiber images 37a and 37b, particularly the outer periphery, changes significantly due to a change in focus, resulting in a white background. This allows the fiber images 37a and 37b to be obtained with background noise removed.

[0054] 6(a) is a conceptual diagram showing a difference image 41b obtained by binarizing this image. As mentioned above, areas of the captured images 35a and 35b where there is little change appear black, and areas where there is a large change appear white. In particular, because the change in focus causes a large change in brightness at the outer edges of the fiber images 37a and 37b, the outer edges of the fiber images 37a and 37b can be clearly identified by binarization.

[0055] Next, as shown in Fig. 6(b), the control unit 30 identifies the center position of the optical fiber 29 (fiber images 37a, 37b) from the difference image 41b. As described above, the outer edges of the fiber images 37a, 37b are clearly identified, so the control unit 30 can accurately grasp the respective circles from the fiber images 37a, 37b. Therefore, the control unit 30 can identify the center points 43a, 43b from the circles obtained from the fiber images 37a, 37b.

[0056] Note that fiber images 37a and 37b in differential images 41a and 41b are based on fiber image 37b, and therefore are blurred. Therefore, the outer diameter and other parameters differ from captured image 35a, which is the reference image. However, captured images 35a and 35b do not change their positions because only the focus of fiber images 37a and 37b changes. Therefore, even if the center points of fiber images 37a and 37b are determined based on out-of-focus captured image 35b, the center positions will be the same as the center positions of fiber images 37a and 37b in captured image 35a.

[0057] 6(c) shows a state in which the determined center points 43a and 43b in the difference image 41b are set to the center positions of the fiber images 37a and 37b in the captured image 35a (reference image). That is, as described above, the positions of the center points 43a and 43b of the fiber images 37a and 37b do not change in the difference image 41b and the captured image 35a, so the positions of the center points 43a and 43b can be combined with the captured image 35a. As a result, the center points 43a and 43b of the respective fiber images 37a and 37b can be accurately determined in the captured image 35a.

[0058] Next, as shown in Fig. 7(a), the image processing unit 33 creates a composite image 45 by aligning and superimposing the fiber images 37a and 37b in the reference images obtained for each optical fiber 29, with their respective centers aligned, and displays the composite image 45 on the display unit 17. The superimposed fiber images 37a and 37b are based on the reference images, and therefore are in focus. Therefore, the positions of the cores and the stress-applying portions can be clearly grasped in each of the fiber images 37a and 37b.

[0059] Note that one of the fiber images 37a and 37b may be inverted and superimposed in the composite image 45. Also, as shown in Fig. 7(a), each of the fiber images 37a and 37b may be displayed independently at the same time along with the composite image 45.

[0060] Next, the control unit 30 rotates at least one of the holder mounting units 11 using the rotation drive unit 19 around an axis that is the opposing direction of the pair of holder mounting units 11, thereby rotationally aligning the pair of optical fiber cores 29. In this way, while viewing the composite image 45, it is possible to perform rotational alignment of the optical fiber cores 29 by performing alignment so that the arrangements of the cores and stress-applying units match, as shown in Fig. 7(b).

[0061] As described above, according to this embodiment, even when light is introduced from the side of the pair of optical fiber cores 29 and leakage light appears in the fiber end face image, the influence of this can be eliminated and the accurate outer edge shapes of the fiber images 37a and 37b can be obtained. Therefore, the center positions of the fiber images 37a and 37b can be accurately obtained in the obtained captured images 35a and 35b. Therefore, a composite image 45 obtained by combining both images can be obtained with high accuracy, and efficient rotational alignment can be performed.

[0062] Furthermore, the fiber images 37a and 37b used in rotational alignment are focused reference images, so the structure at the end face (core arrangement and stress application part arrangement) is clear and does not interfere with rotational alignment.

[0063] Furthermore, when obtaining the captured image 35b with a different focus, the holder mounting portion 11 or the imaging portion 25 is moved, and therefore, without changing the positions of the fiber images 37a and 37b, two captured images with only different focuses can be easily captured by the imaging portion 25. In this case, for example, even if the pair of holder mounting portions 11 are translated in opposing directions, the positions of the fibers in the images do not change, and therefore, images with different focuses can be obtained with high precision.

[0064] In the above-described embodiment, an example was described in which the composite image 45 was created after identifying the center points 43a and 43b, but this is not limiting. For example, by calculating the difference between two captured images, the positions of the fiber images 37a and 37b in the image can be determined. Therefore, it is also possible to identify the position of the cladding of each optical fiber 29 from the center points 43a and 43b. For example, in a case where the brightness of the light sources 23a and 23b is automatically adjusted based on the brightness of the cladding position on the end face of each optical fiber, automatic adjustment of the brightness of the light sources 23a and 23b is also possible because the position of the cladding can be automatically identified.

[0065] Furthermore, since the positions of the fiber images 37a and 37b in the captured image can be grasped, it is also possible to grasp the height position of the reflecting member 21 relative to the optical fiber 29. Therefore, when adjusting the focus, it is possible to perform the adjustment while avoiding interference between the reflecting member 21 and the optical fiber 29. In this way, the center positions of the fiber images 37a and 37b can be used for control other than rotational alignment.

[0066] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not limited to the above-described embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0067] 1...Fusion machine 3. Windshield 5……V groove 7……Electrode 9...Main unit 11...Holder placement portion 13...Clamp 15……Operation unit 17……Display section 19...Rotation drive unit 21...Reflective member 23a, 23b……Light source 25....Imaging unit 27...Holder 29....Optical fiber core 29a………Glass fiber 29b...Resin coating 30...Control unit 31...Transport drive unit 33: Image processing unit 35a, 35b...Captured images 37a, 37b...Fiber images 39……Light leakage part 41a, 41b...Difference images 43a, 43b……center point 45...Composite image 100...Captured image 101a, 101b...Fiber images 103……Light leakage part 105...Binarized image

Claims

1. A fusion splicer for connecting a pair of optical fiber cores, a pair of holder placement sections on which holders for holding optical fiber cores are placed; a light source capable of irradiating light from a side of the optical fiber core placed on the holder placement portion; a reflecting member movable between the pair of holder placement portions; an imaging unit that captures an image reflected by the reflecting member; an image processing unit that processes the image captured by the imaging unit; a control unit capable of adjusting a focus by changing an optical path from an end face of the optical fiber core to the imaging unit; Equipped with the control unit moves the holder placement unit or the imaging unit to capture at least two different images with the imaging unit; The fusion machine is characterized in that the image processing unit is capable of comparing the multiple images obtained, taking the differences, and extracting only those parts where the differences are greater than or equal to a predetermined value to create a difference image.

2. One of the images captured by the imaging unit is a reference image focused on an end face of the optical fiber core, 2. The fusion splicer according to claim 1, wherein the control unit identifies a center position of the optical fiber from the differential image and sets the center position as a center position of the optical fiber in the reference image.

3. 3. The fusion splicer according to claim 2, wherein the image processing unit is capable of creating a composite image by superimposing the reference images obtained for the respective optical fiber cores with their centers aligned.

4. A fusion splicer as described in claim 3, characterized in that it is equipped with a rotational drive unit that can rotate at least one of the holder mounting parts around an axis in the opposing direction of the pair of holder mounting parts, thereby rotationally aligning a pair of optical fiber core wires, and that can perform rotational alignment of the optical fiber core wires using the composite image.

5. 2. The fusion splicer according to claim 1, wherein the control unit is capable of causing the imaging unit to capture two different images by moving the holder placement units in opposing directions of the pair of holder placement units.

Images