Optical fiber beam splitting array beam combining imaging large format light spot synchronous detection device and method

Abstract

The application discloses a kind of optical fiber beam splitting array beam combination imaging large-format light spot synchronous detection device and method, it is related to laser additive manufacturing optical path detection technical field, the device includes front-end optical fiber detection panel, multiple flexible optical fiber bundles, optical fiber beam combination reorganization structure, industrial camera and integrated packaging box;M×N detection point positions are evenly arranged on the front-end optical fiber detection panel;Each flexible optical fiber bundle corresponds a detection point position, is formed by the close arrangement of multiple optical fibers, is arranged in a triangular shape at detection end, for two-dimensional spatial resolution sampling to incident light spot;Optical fiber beam combination reorganization structure is arranged by beam combination according to space mapping rule to each optical fiber bundle end, coupling end is also arranged in a triangular shape;Industrial camera is synchronously imaged, obtains the synchronous two-dimensional imaging of the same time of global light spot.The application can realize the parallel synchronous light spot detection of full-format multiple detection point positions, obtain the complete two-dimensional topographic information of single point position light spot, improve the efficiency and dimension of large-format light spot detection.

Description

Technical Field

[0001] This application relates to the field of optical path detection technology in laser additive manufacturing, and in particular to a device and method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging. Background Technology

[0002] In the field of laser additive manufacturing, the classic scanning optical path of galvanometer paired with field lens (F-Theta lens) is commonly used, which can realize the integrated molding of large-sized components, with a typical effective forming area of ​​up to 300mm×500mm. During the scanning process, it is necessary to detect the spot at different positions within the large area to evaluate the positional accuracy and morphological distortion of the spot.

[0003] Currently, the mainstream testing methods in the industry are divided into two categories: (I) Traditional offline sample ablation testing: an array of spots is ablated on the sample using a laser, and the quality of the spots is evaluated manually or with assistance after the sample is removed. This approach has obvious drawbacks: the test results are not intuitive and rely on secondary equipment analysis; it requires the consumption of special sample consumables, resulting in high production costs; the testing process is cumbersome, requiring shutdown to disassemble and reassemble the sample, resulting in extremely low testing efficiency and failing to meet the needs of high-frequency calibration and online monitoring of the equipment. (II) Commercial single-point scanning testing equipment: represented by PRIMES SFM 2D, this type of equipment can achieve online in-situ testing, without consumables, and at high speed. However, its underlying principle is a single-channel serial detection architecture, which can only scan and collect signals point by point and cannot achieve parallel synchronous acquisition of multiple light spots; at the same time, it can only obtain one-dimensional size information of the beam and cannot output key parameters such as the complete two-dimensional morphology, energy distribution, and circularity distortion of a single light spot. It cannot truly and comprehensively reflect the two-dimensional distortion state of the light spot under a large field of view, and its evaluation dimensions for large field of view aberrations are seriously insufficient.

[0004] Existing fiber array-based detection solutions typically configure only a single fiber at each detection point. Their function is limited to acquiring the integral value of the light intensity at that point and outputting a one-dimensional scalar signal. They cannot reconstruct the two-dimensional spatial distribution information such as the intensity gradient, edge contour, and energy center offset inside the light spot, and therefore cannot meet the detection requirements of large-format laser additive manufacturing for the complete two-dimensional morphology of the light spot.

[0005] In summary, existing technologies have limitations, including the inability to perform parallel and synchronous detection across multiple points in the entire area and the inability to acquire the complete two-dimensional morphology of the light spot. Therefore, there is an urgent need for an online light spot detection solution that can adapt to large-format applications, multi-channel parallel operation, full-area synchronization, and complete coverage of two-dimensional morphology. Summary of the Invention

[0006] The purpose of this application is to provide a device and method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging, which can realize parallel synchronous light spot detection at multiple detection points across the entire area, obtain complete two-dimensional morphological information of a single-point light spot, and improve the efficiency and dimensionality of large-format light spot detection.

[0007] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a large-format spot synchronous detection device for fiber optic beam splitting and combining imaging, comprising: A front-end fiber optic detection panel, wherein M×N detection points are evenly arranged on the front-end fiber optic detection panel, and the distribution area of ​​the detection points corresponds to the laser scanning area to be tested.

[0008] A multi-path flexible fiber bundle, each path of which corresponds to one detection point, is provided. Each flexible fiber bundle consists of multiple closely arranged optical fibers, which are arranged in a triangular pattern at the detection end for two-dimensional spatial resolution sampling of the incident light spot at the detection point. The multiple fiber bundles transmit the optical signals collected at the detection points in parallel and independently.

[0009] The fiber optic bundle recombination structure is used to bundle and arrange the ends of each flexible fiber optic bundle according to a spatial mapping rule, and the multiple fibers are also arranged in a triangular pattern at the coupling end.

[0010] An industrial camera, wherein the target surface of the industrial camera receives the light signal emitted through the optical fiber bundle recombination structure and simultaneously images it, thereby obtaining synchronous two-dimensional imaging of the entire light spot at the same time.

[0011] An integrated encapsulation box is used to fix and encapsulate the front-end fiber optic detection panel, the multi-path flexible fiber bundle, the fiber bundle recombination structure, and the industrial camera.

[0012] Optionally, the flexible fiber bundle is composed of multiple closely arranged optical fibers, specifically including: Each flexible fiber bundle consists of L×L tightly arranged optical fibers; where L≥2.

[0013] Optionally, the optical fiber is a micron-level variable diameter optical fiber, which is integrally formed with a unequal diameter structure at both ends using an optical taper drawing process, including the detection end and the coupling end; the aperture of the coupling end is determined according to the pixel size and number of the industrial camera.

[0014] Optionally, each of the optical fibers is matched with the number of K pixels of the industrial camera, where K ≥ 4.

[0015] Optionally, the total resolution O of the industrial camera satisfies: O>A×M×N×L×L×K; where A is a preset spatial redundancy coefficient, L×L is the number of optical fibers in each flexible optical fiber bundle, and M×N is the total number of detection points.

[0016] Optionally, the incident end face of the optical fiber is uniformly treated using a frosted diffuser process.

[0017] Optionally, the integrated packaging box is configured to be placed directly into the molding powder tank of the laser additive manufacturing equipment to achieve in-situ online detection.

[0018] Secondly, this application provides a method for synchronous detection of large-area light spots in fiber optic beam splitter array combining imaging. The method is implemented based on the aforementioned synchronous detection device for large-area light spots in fiber optic beam splitter array combining imaging, and includes: The device is placed in the molding powder tank of the laser additive manufacturing equipment.

[0019] Multiple optical fibers at each detection point perform two-dimensional spatial resolution sampling on their respective single-point light spots, and collect the optical signals of the laser scanning area under test in parallel.

[0020] Each optical signal is transmitted in parallel through its corresponding flexible optical fiber bundle to the optical fiber combining and reassembling structure, and coupled to the target surface of the industrial camera according to the spatial mapping rule to obtain the combined optical signal.

[0021] The industrial camera synchronously acquires all the combined light signals and images them to obtain independent multi-path light spot images.

[0022] Based on the sub-pixel segmentation algorithm, grayscale gradient analysis is performed on the edge pixels of the light spot image to calculate the energy weight allocation coefficient of each optical fiber between adjacent pixels.

[0023] Based on the energy weighting coefficient, the two-dimensional light field distribution of the spot image is reconstructed, and the two-dimensional morphological feature parameters of the spot image are extracted by the image processing algorithm to obtain synchronous two-dimensional imaging of the global spot at the same time.

[0024] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a large-format light spot synchronous detection device and method for fiber optic beam splitting and combining imaging. By uniformly arranging M×N detection points on the front-end fiber optic detection panel, each detection point corresponds to a flexible fiber bundle composed of multiple tightly arranged fibers. This allows a single detection point to perform two-dimensional spatial resolution sampling of the incident light spot through multiple fibers, solving the problem in existing fiber optic array solutions where only a single fiber is configured at a single point, resulting in only one-dimensional light intensity integral values ​​being output. This enables the acquisition of two-dimensional spatial distribution information of the light spot at a single point. The triangular arrangement of multiple fibers at the detection end increases the fiber area fill rate within the detection end face, reduces the sampling blind zone, and improves the fidelity of two-dimensional spatial resolution sampling of the light spot at a single point. The optical signals collected at each detection point are transmitted independently and in parallel through each flexible fiber bundle. The fiber optic bundle recombination structure combines the ends of various flexible fiber optic bundles according to spatial mapping rules, and then the industrial camera images them synchronously. This solves the problem that the existing single-channel serial detection architecture can only scan point by point and cannot acquire multiple points in parallel synchronously, realizing synchronous imaging of M×N detection points across the entire field of view. By arranging the multiple optical fibers in a triangular pattern at the coupling end, the output ends of each optical fiber are regularly and densely arranged on the camera target surface, reducing the alignment accuracy requirements between the optical fiber coupling end and the camera pixels, and improving the assembly feasibility and mass production adaptability of the device. The front-end optical fiber detection panel, multiple flexible fiber optic bundles, fiber optic bundle recombination structure, and industrial camera are integrated into an integrated package, realizing the overall miniaturization of the device and the ability to deploy in-situ online detection, improving the efficiency and dimensionality of large-area spot detection. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of a large-format spot synchronous detection device for fiber optic beam splitting array combining imaging provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the fiber bundle array arrangement of the front-end fiber detection panel provided in another embodiment of this application; Figure 3 This is a schematic diagram of a single-bundle fiber arrangement provided in another embodiment of this application; Figure 4 This is a schematic diagram of a single optical fiber drawing process provided in another embodiment of this application; Figure 5 A schematic diagram illustrating the matching of a flexible fiber bundle coupling end with an industrial camera pixel according to another embodiment of this application; Figure 6 This is a flowchart illustrating a method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging, provided as an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] In one exemplary embodiment, such as Figure 1 As shown, a large-format spot synchronous detection device for fiber optic beam splitting and combining imaging is provided, comprising: A front-end fiber optic detection panel, wherein M×N detection points are evenly arranged on the front-end fiber optic detection panel, and the distribution area of ​​the detection points corresponds to the laser scanning area to be tested.

[0030] A multi-path flexible fiber bundle, each path of which corresponds to one detection point, is provided. Each flexible fiber bundle consists of multiple closely arranged optical fibers, which are arranged in a triangular pattern at the detection end for two-dimensional spatial resolution sampling of the incident light spot at the detection point. The multiple fiber bundles transmit the optical signals collected at the detection points in parallel and independently.

[0031] The fiber optic bundle recombination structure is used to bundle and arrange the ends of each flexible fiber optic bundle according to a spatial mapping rule, and the multiple fibers are also arranged in a triangular pattern at the coupling end.

[0032] An industrial camera, wherein the target surface of the industrial camera receives the light signal emitted through the optical fiber bundle recombination structure and simultaneously images it, thereby obtaining synchronous two-dimensional imaging of the entire light spot at the same time.

[0033] An integrated encapsulation box is used to fix and encapsulate the front-end fiber optic detection panel, the multi-path flexible fiber bundle, the fiber bundle recombination structure, and the industrial camera.

[0034] The overall structure of this application embodiment adopts an integrated design, with all optical acquisition, transmission, and coupling structures uniformly encapsulated inside a square box. It can be directly placed on the printing and forming work surface, adapting to the detection requirements of large-format scanning fields. In specific implementation, this application embodiment uses a 400mm×400mm large-format scanning field for illustration, but this size can be adjusted according to actual needs.

[0035] Through the aforementioned device, this embodiment abandons the existing one-dimensional integral sampling mode of "single point, single fiber" in fiber optic detection schemes, and arranges an optical fiber bundle composed of multiple micron-sized variable-diameter optical fibers densely packed at each detection point. Parallel sampling of multiple fibers at a single point is equivalent to embedding a multi-pixel miniature imaging unit at each point; synchronous light collection at multiple detection points enables synchronous two-dimensional imaging of the full-area light spot morphology, realizing the transformation from outputting a one-dimensional scalar (integral value of light intensity) to outputting a two-dimensional matrix (light spot image); furthermore, based on the "single point, multiple fibers, bundle splitting" imaging mechanism, the two-dimensional contour morphology and energy distribution of each light spot can be completely acquired, accurately identifying large field-of-view aberrations such as light spot elliptical distortion, edge tailing, local energy unevenness, center shift, and irregular distortion, completely solving the problems of existing detection methods. The current testing methods can only measure one-dimensional spot size or light intensity integral value, which is a shortcoming in the industry. Meanwhile, the embodiments of this application adopt a triangular (triangular densely packed) arrangement at the detection end of the fiber bundle, which minimizes the gap between adjacent fibers and maximizes the area fill rate, effectively reducing the blind area of ​​spot sampling and improving the true fidelity of single-point two-dimensional spatial resolution. In addition, the front-end fiber detection panel, multiple flexible fiber bundles, fiber bundle recombination structure and industrial camera are integrated and packaged in an integrated package, realizing the overall miniaturization of the device and the ability to deploy in-situ online detection.

[0036] In another exemplary embodiment of this application, each flexible fiber bundle is composed of L×L tightly arranged optical fibers; wherein, L≥2.

[0037] The optical fiber is a micron-level variable diameter optical fiber, which is integrally formed with a different diameter at both ends using an optical taper drawing process, including the detection end and the coupling end; the aperture of the coupling end is determined according to the pixel size and number of the industrial camera.

[0038] Each of the optical fibers is matched with K pixels of the industrial camera, where K ≥ 4.

[0039] The device in this embodiment of the application is equipped with a front-end fiber optic detection panel, such as Figure 2As shown, the effective detection area of ​​the front-end fiber optic detection panel is 400mm×400mm. A 13×13 flexible fiber bundle detection array is evenly arranged on the front-end fiber optic detection panel, totaling 169 independent detection areas, uniformly covering the entire printing working area with no detection blind spots or overlapping areas. This array layout can completely align with the full-domain calibration logic of the large-format galvanometer optical path, accurately matching the aberration gradient distribution characteristics from the center to the edge of the large-field lens.

[0040] The key structural difference from the existing single-fiber point-based scheme is that each detection point on the front-end fiber optic detection panel corresponds to a fiber bundle, which is composed of multiple micron-sized variable-diameter fibers arranged closely together to achieve two-dimensional spatial resolution sampling of the single-point light spot; the fiber bundles at each point transmit in parallel and independently without interfering with each other.

[0041] In specific implementations, to more clearly illustrate the arrangement structure of the optical fibers inside the flexible optical fiber bundle, this application only provides a portion of the arrangement structure of the optical fibers inside the flexible optical fiber bundle. The complete structure can be found by referring to... Figure 3 Further expansion. Each flexible fiber bundle consists of 50×50 (totaling 2500) micron-sized variable-diameter fibers arranged in a tightly packed pattern. At the detection end, the fibers within the flexible fiber bundle are arranged in a triangular (triangular close-packed) pattern, meaning the cores of three adjacent fibers are arranged in an equilateral triangle. This minimizes the gaps between fibers, significantly increasing the fiber's area fill rate on the detection surface, effectively reducing the blind zone of the light spot sampling, and improving the fidelity of the two-dimensional spatial resolution of the single-point light spot. The internal structure of a single fiber bundle is an ultra-high-density triangular microarray structure. Its imaging principle is as follows: each fiber independently samples a micro-element region of the light spot at that point, and the parallel output of 2500 fibers constitutes the complete two-dimensional light field distribution map of the light spot at that point, which is equivalent to embedding a 2500-pixel miniature imaging unit at each detection point. The simultaneous light collection at 169 points enables simultaneous two-dimensional imaging of 169 light spot morphology images across a full 400mm×400mm area, fundamentally solving the technical defect of the single-fiber solution of "one value per point, light intensity but no image".

[0042] like Figure 4 As shown, the optical fiber is integrally formed using a taper drawing process and has a structure with different diameters at both ends.

[0043] The detection end aperture is 50μm: accurately matching the accuracy requirements of large-format light spot detection, efficiently acquiring details of light spot micro-deformation and energy distribution, and completely preserving the spatial resolution of light spot morphology.

[0044] The aperture at the coupling end is determined based on the pixel size and number of the industrial camera target surface. In practical implementation, the fiber arrangement at the coupling end also adopts a triangular (triangular close-packed) structure. For example... Figure 5As shown, the coverage area of ​​a single optical fiber on the target surface of an industrial camera is equivalent to 9 pixels (a 3×3 pixel area). This design eliminates the need for a strict 1:1 correspondence between the optical fiber and the pixels of the industrial camera, significantly reducing the alignment accuracy requirements and engineering complexity of the fiber coupling end. Even with a large offset between the fiber end face and the pixel grid, the optical signal output from the fiber can still stably fall within the corresponding pixel area, greatly improving the tolerance of device assembly and mass production feasibility. Simultaneously, the sub-pixel-level spot reconstruction algorithm can fully recover the true light intensity distribution of the fiber sampling points without sacrificing detection accuracy due to the increased number of pixels covered by a single fiber.

[0045] All optical fibers undergo uniform treatment using a frosted diffused process on their incident end faces. This diffused optical structure effectively eliminates light-gathering deviations and imaging distortions caused by different incident angles of the laser, significantly suppresses spot distortion and uneven energy acquisition caused by oblique incident light rays at different scanning angles of the galvanometer, and ensures the consistency and stability of spot acquisition across the entire swath and all scanning angles.

[0046] This application fully utilizes the structural advantages of flexible fiber bundles, which can be flexibly bent and arbitrarily routed. The 13×13 flexible fiber bundles at the front end are neatly arranged and layered within an integrated packaging box, eliminating the need for complex rigid optical path structures. The overall size is compact and free from spatial interference. Each fiber independently transmits optical signals, and the bundles are isolated from each other, preventing crosstalk.

[0047] All fiber bundle ends undergo orderly bundle recombination. First, the fibers are recombined in a single fiber bundle, and then multiple fiber bundles are arranged on the camera target surface. Subsequently, image transmission is performed according to spatial mapping rules, and the image is precisely coupled to the back-end industrial camera target surface. This transforms the front-end two-dimensional distributed detection array into a multi-path imaging area that can be independently identified by the camera, enabling 169 light spots to simultaneously collect light, transmit data, and image, completely abandoning the traditional single-channel serial point-by-point scanning detection mode.

[0048] To ensure imaging stability and avoid interference from fiber coupling assembly process errors and spatial occupancy issues, this application embodiment sets a quantitative matching constraint relationship, ensuring that the total resolution O of the industrial camera satisfies: O > A×M×N×L×L×K; where A is a preset spatial redundancy coefficient, L×L is the number of fibers in each flexible fiber bundle, and M×N is the total number of detection points. In specific implementation, A=1.2 is taken to reserve spatial redundancy for the industrial camera, fiber coupling process, and bundle arrangement, effectively avoiding imaging area overflow, pixel crowding, and signal crosstalk issues. Based on this matching logic, the array structure of this application embodiment is not limited to the 13×13 specification and can be flexibly expanded to an M×N arbitrary row and column fiber array, adapting to large-format laser 3D printing equipment of different sizes and different precision detection requirements, possessing strong versatility and scalability.

[0049] The fiber array and the imaging pixels of the industrial camera in this application have a flexible and adaptable quantitative matching mechanism, which can achieve dynamic parameter optimization based on the ultra-high resolution characteristics of the industrial camera. At present, the resolution of industrial cameras can easily reach the 500M pixel level, with sufficient redundancy space. The three core parameters can be flexibly adjusted according to the actual detection accuracy and size adaptation requirements: the number of fiber bundle arrays M×N, the number of fibers L inside a single fiber bundle, and the number of camera pixels matched by a single variable diameter fiber K (K is usually 4~16, that is, each fiber covers 4~16 pixels, preferably K=9, depending on the matching relationship between the pixel size of the industrial camera and the aperture of the fiber coupling end).

[0050] In another exemplary embodiment of this application, the integrated packaging box is configured to be directly placed in the molding powder tank of a laser additive manufacturing equipment to achieve in-situ online detection.

[0051] Leveraging the advantages of flexible fiber optic integration, this embodiment integrates the front-end fiber optic detection panel, multiple flexible fiber bundles, fiber optic bundling and reassembly structure, and industrial camera into a single square box module. The overall structure is compact and highly protective, allowing direct placement inside the powder chamber of a laser 3D printing device. It perfectly adapts to conventional field lens optical path layouts and printing cavity spatial structures without requiring modifications to the original optical path, mechanical structure, or powder forming system. Installation is convenient, and it boasts wide adaptability, effectively isolating printing dust and airflow interference, making it suitable for long-term industrial mass production conditions.

[0052] In one exemplary embodiment, such as Figure 6 As shown, a method for synchronous detection of large-format light spots in fiber optic beam splitter array combining imaging is provided. This method is based on the aforementioned fiber optic beam splitter array combining imaging large-format light spot synchronous detection device and specifically includes the following steps A1 to A6: Step A1: Place the device in the molding powder tank of the laser additive manufacturing equipment.

[0053] In step A2, multiple optical fibers at each detection point perform two-dimensional spatial resolution sampling on their respective single-point light spots, and collect the optical signals of the laser scanning area to be tested in parallel.

[0054] In step A3, each optical signal is transmitted in parallel through its corresponding flexible optical fiber bundle to the optical fiber combining and reassembling structure, and coupled to the target surface of the industrial camera according to the spatial mapping rule to obtain the combined optical signal.

[0055] In step A4, the industrial camera synchronously acquires all the combined light signals and images them to obtain independent multi-path light spot images.

[0056] Step A5: Based on the sub-pixel segmentation algorithm, perform grayscale gradient analysis on the edge pixels of the light spot image and calculate the energy weight allocation coefficient of each optical fiber between adjacent pixels.

[0057] Step A6: Based on the energy weighting coefficient, reconstruct the two-dimensional light field distribution of the light spot image, and extract the two-dimensional morphological feature parameters of the light spot image using an image processing algorithm to obtain synchronous two-dimensional imaging of the entire light spot at the same time. The two-dimensional morphological feature parameters include size, center offset, roundness, contour distortion, and two-dimensional energy distribution.

[0058] As an optional implementation, the method further includes: The two-dimensional morphological feature parameters are compared with preset standard parameters to generate a global aberration distribution map, which is then output to the galvanometer correction system for calibration and compensation.

[0059] In practice, the global aberration distribution map describes the correspondence between the centroid position of the light spot and the galvanometer driving signal. When the measured value of the light spot centroid is found to be inconsistent with the set value, the galvanometer driving signal is adjusted to match it.

[0060] This application embodiment performs full-domain precise calibration of optical fibers and industrial camera imaging pixels to establish a stable mapping relationship. During system factory shipment and periodic calibration, the correspondence between a single optical fiber and the pixel area of ​​the industrial camera is calibrated, ensuring that the two-dimensional light field information of the light spot at each detection point at the front end can stably correspond to the fixed pixel area of ​​the camera.

[0061] In practical implementation, the light spot image acquired by each flexible fiber bundle corresponds to a certain pixel area of ​​the industrial camera. Since a single fiber corresponds to 9 pixels (i.e., a 3×3 pixel area, rather than a strict 1:1 correspondence), the imaging areas of the 13×13 fiber bundles are neatly arranged on the camera target surface, with clear boundaries and no overlap. The design of a single fiber covering 9 pixels significantly reduces the alignment accuracy requirements of the fiber coupling end. In engineering, it is only necessary to ensure that the center of the imaging spot on the fiber end face falls within the corresponding 3×3 pixel area, without the need for sub-micron level precision alignment, making the engineering assembly of large-scale fiber arrays feasible.

[0062] To achieve high-precision registration between optical fibers and pixels, this application introduces a sub-pixel segmentation algorithm. Specifically, during pixel mapping calibration, the image of a single optical fiber end face on the industrial camera target surface is not perfectly aligned with the pixel grid, but rather exhibits a sub-pixel-level offset. This application employs a sub-pixel edge detection and centroid subdivision algorithm on the edge pixels of the optical fiber imaging spot to accurately calculate the energy weight allocation coefficient of each optical fiber in the edge pixels (i.e., the energy distribution ratio of the light intensity of that optical fiber among adjacent pixels). Based on this, the system can reconstruct a two-dimensional light field distribution map with a resolution higher than the native pixel resolution of the industrial camera, further improving the detection accuracy of the single-point spot morphology. It is worth emphasizing that a single optical fiber covers 9 pixels instead of 1 pixel, which not only does not affect the effectiveness of the sub-pixel segmentation algorithm, but also provides richer edge transition pixel information, making the calculation of the energy weight allocation coefficient more accurate and reliable.

[0063] The system automatically segments the light spot images of each path through image algorithms, and combines sub-pixel-level fiber positioning and weight allocation to independently extract parameters such as light spot size, center offset, roundness, contour distortion, and two-dimensional energy distribution at each point, thereby achieving high-precision quantitative analysis of global aberrations.

[0064] This application also provides an application scenario in which the aforementioned fiber optic beam splitter array combining imaging large-format spot synchronous detection device is applied. Specifically, the fiber optic beam splitter array combining imaging large-format spot synchronous detection device provided in this application embodiment can be applied in the optical path detection scenario of laser additive manufacturing. This optical path detection scenario includes a spot acquisition stage, a spot image processing stage, and a galvanometer calibration stage. After the laser is emitted from the galvanometer scanning field, it enters the spot acquisition stage. The multi-path flexible fiber bundles on the front-end fiber optic detection panel synchronously sample the entire spot in two dimensions, obtaining synchronous two-dimensional imaging of the entire spot at the same time, and then entering the downstream spot image processing stage. The detection device provided in this application embodiment belongs to the spot acquisition stage. Specifically, in the optical path detection process for the galvanometer scanning field, the device can perform two-dimensional spatial resolution sampling of the spot at each detection point within the scanning area, and transmit the combined optical signal to the industrial camera for synchronous imaging, thereby providing two-dimensional morphological data of the entire spot for subsequent galvanometer calibration.

[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A large-format spot synchronous detection device for fiber optic beam splitting and combining imaging, characterized in that, The device includes: A front-end fiber optic detection panel, wherein M×N detection points are evenly arranged on the front-end fiber optic detection panel, and the distribution area of ​​the detection points corresponds to the laser scanning area to be tested; The system comprises multiple flexible fiber bundles, each corresponding to a detection point. Each flexible fiber bundle consists of multiple closely arranged optical fibers, which are arranged in a triangular pattern at the detection end for two-dimensional spatial resolution sampling of the incident light spot at the detection point. The multiple fiber bundles transmit the optical signals collected at the detection points in parallel and independently. The fiber optic bundle recombination structure is used to bundle and arrange the ends of each flexible fiber optic bundle according to a spatial mapping rule, and the multiple fibers are also arranged in a triangular pattern at the coupling end. An industrial camera, wherein the target surface of the industrial camera receives the light signal emitted through the optical fiber bundle recombination structure and simultaneously images it, thereby obtaining synchronous two-dimensional imaging of the entire light spot at the same time. An integrated encapsulation box is used to fix and encapsulate the front-end fiber optic detection panel, the multi-path flexible fiber bundle, the fiber bundle recombination structure, and the industrial camera.

2. The fiber optic beam splitting and combining imaging large-format spot synchronous detection device according to claim 1, characterized in that, The flexible fiber bundle is composed of multiple closely arranged optical fibers, specifically including: Each flexible fiber bundle consists of L×L tightly arranged optical fibers; where L≥2.

3. The fiber optic beam splitter array combining imaging large-format spot synchronous detection device according to claim 2, characterized in that, The optical fiber is a micron-level variable diameter optical fiber, which is integrally formed with a different diameter at both ends using an optical taper drawing process, including the detection end and the coupling end; the aperture of the coupling end is determined according to the pixel size and number of the industrial camera.

4. The fiber optic beam splitter array combining imaging large-format spot synchronous detection device according to claim 3, characterized in that, Each of the optical fibers is matched with K pixels of the industrial camera, where K ≥ 4.

5. The fiber optic beam splitting and combining imaging large-format spot synchronous detection device according to claim 4, characterized in that, The total resolution O of the industrial camera satisfies: O>A×M×N×L×L×K; where A is a preset spatial redundancy coefficient, L×L is the number of optical fibers in each flexible optical fiber bundle, and M×N is the total number of detection points.

6. The optical fiber beam splitting and combining imaging large-format spot synchronous detection device according to claim 1, characterized in that, The incident end face of the optical fiber is uniformly treated using a frosted diffuser process.

7. The fiber optic beam splitting and combining imaging large-format spot synchronous detection device according to claim 1, characterized in that, The integrated packaging box is configured to be placed directly into the molding powder tank of the laser additive manufacturing equipment to achieve in-situ online detection.

8. A method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging, characterized in that, The method is implemented based on the large-format spot synchronous detection device for fiber optic beam splitting and combining imaging as described in any one of claims 1-7, and specifically includes the following steps: The device is placed in the forming powder tank of the laser additive manufacturing equipment; Multiple optical fibers at each of the detection points perform two-dimensional spatial resolution sampling on their respective single-point light spots, and collect the optical signals of the laser scanning area to be tested in parallel. Each optical signal is transmitted in parallel through its corresponding flexible optical fiber bundle to the optical fiber combining and reassembling structure, and coupled to the target surface of the industrial camera according to the spatial mapping rule to obtain the combined optical signal; The industrial camera synchronously acquires all the combined light signals and images them to obtain independent multi-path light spot images. Based on the sub-pixel segmentation algorithm, gray-level gradient analysis is performed on the edge pixels of the light spot image to calculate the energy weight allocation coefficient of each optical fiber between adjacent pixels. Based on the energy weighting coefficient, the two-dimensional light field distribution of the spot image is reconstructed, and the two-dimensional morphological feature parameters of the spot image are extracted by the image processing algorithm to obtain synchronous two-dimensional imaging of the global spot at the same time.

9. The method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging according to claim 8, characterized in that, The two-dimensional morphological feature parameters include size, center offset, roundness, contour distortion, and two-dimensional energy distribution.

10. The method for synchronous detection of large-format light spots in fiber optic beam splitting and combining imaging according to claim 8, characterized in that, The method further includes: The two-dimensional morphological feature parameters are compared with preset standard parameters to generate a global aberration distribution map, which is then output to the galvanometer correction system for calibration and compensation.

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