A method for positioning a light tip of an infrared star guide camera of a 1064nm laser ranging system

Abstract

The present disclosure is a method for positioning the light tip of an infrared star guide camera of a 1064nm laser ranging system, and relates to the technical field of space debris laser ranging. The method comprises: performing multi-stage preprocessing on the 1064nm laser beam image collected by the infrared star guide camera; extracting the laser beam profile from the preprocessed image; constructing two types of structural feature lines based on the profile extraction result, and determining the intersection of the two types of structural feature lines as the light tip positioning point. The present disclosure effectively solves the positioning problem caused by strong noise and beam dispersion of the infrared star guide camera, has high positioning accuracy and strong stability, is suitable for complex observation scenes of the 1064nm laser ranging system, significantly improves the reliability of laser debris ranging, and provides key technical support for space debris orbit monitoring.

Description

Technical Field

[0001] This disclosure relates to the field of laser ranging technology for space debris, specifically to a method for optical tip positioning under strong noise background of an infrared guide star camera in a 1064nm laser ranging system. Background Technology

[0002] With the expansion of low-Earth orbit satellite constellation deployments, the number of space debris has exceeded 60,000. Their high-speed motion poses a deadly threat to spacecraft in orbit, making the need for high-precision Debris Laser Ranging (DLR) technology for orbit monitoring increasingly urgent. The laser beam tip, as a direct representation of the laser emission direction, determines the laser pointing correction effect through its positioning accuracy, making it a core component of DLR technology.

[0003] In existing 1064nm laser ranging systems, infrared guide star cameras suffer from problems such as strong background noise, discontinuous beam edge dispersion, and poor symmetry in the acquired laser images due to atmospheric scattering, system errors, and environmental noise, making tip positioning extremely difficult. Although existing technologies have improved positioning performance through filtering, edge detection, and deep learning, they still suffer from shortcomings such as insufficient equipment adaptability, limited anti-interference capabilities in complex scenes, and difficulty in simultaneously preserving faint outline tips and suppressing noise, thus failing to meet the precise positioning requirements of infrared guide star cameras.

[0004] Therefore, there is an urgent need for a tip positioning method that is compatible with the characteristics of the infrared guide star camera in a 1064nm laser ranging system. Summary of the Invention

[0005] To address the problems existing in the prior art, the main objective of this disclosure is to provide a method for positioning the optical tip of an infrared guide camera in a 1064nm laser ranging system, which balances noise suppression and contour preservation, thereby improving positioning accuracy and adaptability.

[0006] To achieve the above objectives, this disclosure provides a method for positioning the optical tip of an infrared guide star camera in a 1064nm laser ranging system, comprising:

[0007] S1: Perform multi-level preprocessing on the 1064nm laser beam image acquired by the infrared guide star camera;

[0008] S2: Extract the laser beam contour from the preprocessed image;

[0009] S3: Based on the contour extraction results, construct two types of structural feature lines and determine the intersection of the two types of structural feature lines as the optical tip positioning point.

[0010] In the above scheme, the multi-level preprocessing of the 1064nm laser beam image acquired by the infrared guide star camera in step S1 includes: sequentially performing morphological opening and closing operations, mean filtering, Otsu threshold segmentation with correction, main contour screening and Gaussian blur processing on the 1064nm laser beam image acquired by the infrared guide star camera to achieve noise suppression and beam contour preservation.

[0011] In the above scheme, the morphological opening and closing operation includes: first performing a morphological opening operation, that is, performing an erosion operation and then a dilation operation to remove discrete noise points in the background region; then performing a morphological closing operation, that is, performing a dilation operation and then an erosion operation to fill the tiny closed regions inside the beam contour and regularize the contour shape.

[0012] In the above scheme, the execution of mean filtering includes: performing mean filtering on the image to suppress sudden changes in image grayscale, reduce pixel value fluctuations, and provide a stable pixel distribution basis for threshold segmentation.

[0013] In the above scheme, the execution of modified Otsu threshold segmentation includes: using the threshold initially determined by the Otsu method as a benchmark, adding a certain Otsu threshold correction amount according to the image features to complete image binarization, balancing noise suppression and beam information preservation; wherein, the Otsu threshold correction amount is 20, and the condition for completion is that the laser beam tip shape is clearly visible in the image.

[0014] In the above scheme, the main contour screening includes: identifying white connected regions in the image based on the principle of pixel gray-level gradient change, calculating the area of ​​each connected region, selecting the region with the largest area ratio as the main contour of the laser beam, and eliminating small-area isolated bright spot noise.

[0015] In the above scheme, the implementation of Gaussian blur processing includes: smoothing jagged artifacts on the contour edges by weighted averaging with a Gaussian blur kernel, and then restoring the clear contour by global threshold binarization, taking into account both edge smoothness and original shape.

[0016] In the above scheme, the morphological opening and closing operation adopts a 3×3 structuring element, the mean filtering window size is 5×5, and the Gaussian blur kernel size is 3×3.

[0017] In the above scheme, the laser beam contour extraction of the preprocessed image in step S2 includes: using the Snake active contour model to extract the contour of the preprocessed image to obtain the initial contour; and using the aperture method to perform segmented fitting of the initial contour to obtain the closed straight line segment contour.

[0018] In the above scheme, the step of using the Snake active contour model to extract contours from the preprocessed image to obtain an initial contour includes: initializing the Snake contour curve and setting energy function parameters; iteratively optimizing the energy function to drive the contour to converge toward the beam edge to obtain the initial contour.

[0019] In the above scheme, the energy function expression is:

[0020]

[0021] Where v(s)=(x(s),y(s)) is the parametric profile curve, E int For internal energy, E ext The external energy is used to drive the contour to converge toward the beam edge to obtain the initial contour. This is based on the energy minimization criterion. Through the synergistic effect of internal and external energy, the contour is driven to converge toward the beam edge, and the beam contour is accurately extracted. The internal energy is used to control the smoothness and continuity of the contour, while the external energy is used to drive the contour to converge toward the beam edge.

[0022] In the above scheme, the method of using the aperture method to segment and fit the initial contour to obtain a closed straight line segment contour includes: setting an angle threshold θ0 and a distance threshold d0, segmenting and fitting discrete contour points through distance constraints and angle constraints, transforming the contour into a closed straight line segment, completing the contour polygon approximation, and improving the contour approximation accuracy.

[0023] In the above scheme, the angle threshold θ0 = 30° and the distance threshold d0 = 10 pixels; the distance constraint conditions include: the Euclidean distance from the point to be determined to the vertex of the light bar ≤ the preset distance threshold d0; the angle constraint conditions include: the angle between the reference direction of the light bar and the direction pointed to by the point to be determined ≤ the preset angle threshold θ0; only points that satisfy both constraints at the same time are determined to be points within the current straight line segment, otherwise piecewise fitting is triggered.

[0024] In the above scheme, the two types of structural feature lines mentioned in step S3 include: the overall fitting line of all sampling points; and the upper outermost contour fitting line that connects to the leftmost sampling point among all contour fitting lines.

[0025] As can be seen from the above technical solution, the infrared guide star camera tip positioning method for the 1064nm laser ranging system provided in this disclosure has the following advantages over the prior art:

[0026] 1. The 1064nm laser ranging system infrared guide camera tip positioning method provided in this disclosure addresses the problems of strong noise interference, beam contour distortion, and insufficient positioning accuracy and stability in the existing technology of infrared guide camera tip positioning. By adopting three core steps, namely multi-level image preprocessing, laser beam contour extraction, and tip positioning point determination, it achieves noise suppression and accurate preservation of beam contour, solves the core problems of strong noise and contour blurring in infrared guide camera images, and provides a tip positioning method that balances noise suppression and contour preservation, has high positioning accuracy, and strong adaptability.

[0027] 2. The infrared guide camera tip positioning method for the 1064nm laser ranging system provided in this disclosure adopts a combination of the Snake model and the aperture method, which improves the accuracy and robustness of contour extraction.

[0028] 3. The infrared guide camera tip positioning method for the 1064nm laser ranging system provided in this disclosure clarifies the optimal positioning point through quantitative analysis of the intersection of characteristic lines, effectively avoiding beam distortion interference.

[0029] 4. Experimental verification shows that the infrared guide camera tip positioning method of the 1064nm laser ranging system provided in this disclosure effectively solves the positioning problem caused by strong noise and beam dispersion of the infrared guide camera. It has high positioning accuracy and strong stability, is suitable for the complex observation scenarios of the 1064nm laser ranging system, significantly improves the reliability of laser debris ranging, and provides key technical support for space debris orbit monitoring. Attached Figure Description

[0030] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0031] Figure 1 This is a flowchart of the infrared guide star camera tip positioning method for a 1064nm laser ranging system according to an embodiment of this disclosure.

[0032] Figure 2 This is a comparison image before and after multi-level preprocessing according to an embodiment of the present disclosure, used to demonstrate the effect of preprocessing on noise suppression and contour preservation.

[0033] Figure 3 The images shown are laser beam profile extraction results under different Otsu thresholds according to embodiments of this disclosure, used to illustrate the necessity of threshold correction.

[0034] Figure 4 The diagram shows a comparison of the effects of different contour fitting methods according to embodiments of the present disclosure, used to illustrate the advantages of the aperture method.

[0035] Figure 5This describes the changes in the shape of the laser beam and the contour recognition process throughout the entire contour extraction process according to embodiments of this disclosure.

[0036] Figure 6 This is a schematic diagram of the distribution of various structural feature lines on the original image according to embodiments of the present disclosure, used to clarify the feature lines and finally select the feature point construction method.

[0037] Figure 7 The results show the real-time identification of the optical tip position during actual testing in accordance with the embodiments of this disclosure.

[0038] Figure 8 The target ranging result is shown in accordance with the embodiments of this disclosure, wherein the red line represents the effective signal area. Detailed Implementation

[0039] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should be noted that the terms used herein are to be interpreted in accordance with the context of this specification and not in an idealized or overly rigid manner.

[0041] The shapes and dimensions in the accompanying drawings do not reflect actual size and proportion, but are merely illustrative of embodiments of this disclosure. Furthermore, any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The use of ordinal numbers, such as “S1,” “S2,” “S3,” etc., to modify steps in a claim, does not in itself imply any prior ordinal number for that claim step, nor does it represent the order of one claim step with another, or the order of manufacturing processes. These ordinal numbers are used only to clearly distinguish one claim step with a given name from another claim step.

[0042] Furthermore, the use of "comprising" or "including" in the text does not exclude the presence of elements or steps not listed in the claims. The use of "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0043] To address the problems of strong noise interference, beam profile distortion, and insufficient positioning accuracy and stability in existing infrared guide star camera tip positioning technologies, the 1064nm laser ranging system infrared guide star camera tip positioning method disclosed in this disclosure achieves noise suppression and accurate beam profile preservation by employing three core steps: multi-level image preprocessing, laser beam profile extraction, and tip positioning point determination. This solves the core problems of strong noise and profile blurring in infrared guide star camera images and is a tip positioning method that balances noise suppression and profile preservation, has high positioning accuracy, and strong adaptability.

[0044] like Figure 1 As shown, Figure 1 This is a flowchart of a method for positioning the optical tip of an infrared guide star camera in a 1064nm laser ranging system according to an embodiment of this disclosure. The method includes the following steps:

[0045] Step S1: Perform multi-level preprocessing on the 1064nm laser beam image acquired by the infrared guide star camera.

[0046] In this step, the 1064nm laser beam image acquired by the infrared guide star camera undergoes multi-level preprocessing, including: sequentially performing morphological opening and closing operations, mean filtering, Otsu threshold segmentation with correction, main contour filtering, and Gaussian blurring on the 1064nm laser beam image acquired by the infrared guide star camera, thereby achieving noise suppression and beam contour preservation.

[0047] Optionally, the morphological opening and closing operation includes: first performing a morphological opening operation, that is, performing an erosion operation and then a dilation operation to remove discrete noise points in the background region; then performing a morphological closing operation, that is, performing a dilation operation and then an erosion operation to fill the tiny closed regions inside the beam profile and regularize the profile shape.

[0048] Optionally, the mean filtering includes: performing mean filtering on the image to suppress sudden changes in image grayscale, reduce pixel value fluctuations, and provide a stable pixel distribution basis for threshold segmentation.

[0049] Optionally, the execution of modified Otsu threshold segmentation includes: using the threshold initially determined by the Otsu method as a benchmark, adding a certain Otsu threshold correction amount according to the image features to complete image binarization, balancing noise suppression and beam information preservation; wherein, the Otsu threshold correction amount is 20, and the condition for completion is that the laser beam tip shape is clearly visible in the image.

[0050] Optionally, the main contour screening includes: identifying white connected regions in the image based on the principle of pixel gray-level gradient abrupt change, calculating the area of ​​each connected region, selecting the region with the largest area ratio as the main contour of the laser beam, and eliminating small-area isolated bright spot noise.

[0051] Optionally, the Gaussian blurring process includes: smoothing jagged artifacts on the contour edges by weighted averaging with a Gaussian blur kernel, and then restoring the clear contour by global threshold binarization, taking into account both edge smoothness and the original shape.

[0052] Optionally, the morphological opening and closing operation uses a 3×3 structuring element, the mean filtering window size is 5×5, and the Gaussian blur kernel size is 3×3.

[0053] Step S2: Extract the laser beam contour from the preprocessed image.

[0054] In this step, the laser beam contour extraction of the preprocessed image includes: using the Snake active contour model to extract the contour of the preprocessed image to obtain an initial contour; and using the aperture method to perform segmented fitting of the initial contour to obtain a closed straight line segment contour.

[0055] The step of using the Snake active contour model to extract contours from the preprocessed image to obtain an initial contour includes: initializing the Snake contour curve and setting energy function parameters; iteratively optimizing the energy function to drive the contour to converge toward the beam edge to obtain the initial contour.

[0056] Optionally, the energy function expression is:

[0057]

[0058] Where v(s)=(x(s),y(s)) is the parametric profile curve, E int For internal energy, E ext External energy. The iteratively optimized energy function, which drives the profile to converge towards the beam edge to obtain the initial profile, is based on the energy minimization criterion. Through the synergistic effect of internal and external energy, it drives the profile to converge towards the beam edge, accurately extracting the beam profile. Here, the internal energy controls the smoothness and continuity of the profile, while the external energy drives the profile to converge towards the beam edge.

[0059] The method of using the aperture method to segment and fit the initial contour to obtain a closed straight line segment contour includes: setting an angle threshold θ0 and a distance threshold d0, segmenting and fitting discrete contour points through distance constraints and angle constraints, transforming the contour into a closed straight line segment, completing the polygonal approximation of the contour, and improving the contour approximation accuracy.

[0060] Optionally, the angle threshold θ0 = 30° and the distance threshold d0 = 10 pixels; the distance constraint includes: the Euclidean distance from the point to be determined to the vertex of the light bar ≤ the preset distance threshold d0; the angle constraint includes: the angle between the light bar reference direction and the direction pointed to by the point to be determined ≤ the preset angle threshold θ0; only points that simultaneously satisfy both constraints are determined as points within the current straight line segment, otherwise piecewise fitting is triggered.

[0061] Step S3: Construct two types of structural feature lines based on the contour extraction results, and determine the intersection of the two types of structural feature lines as the optical tip positioning point.

[0062] In this step, based on the contour extraction results, two types of structural feature lines were constructed through experiments. The intersection of these two types of structural feature lines was selected as the positioning point and determined as the laser tip positioning point. The two types of structural feature lines include: the overall fitting line for all sampling points; and the outermost upper contour fitting line connecting the leftmost sampling point among all contour fitting lines. This is used to characterize the laser beam tip position in the infrared guide star camera.

[0063] Example:

[0064] 1. Experimental equipment and parameter settings

[0065] Equipment: 1064nm wavelength integrated space target laser ranging telescope, infrared guide star camera.

[0066] Preprocessing parameters: Morphological operations use a 3×3 structuring element, the mean filter window size is 5×5, the Otsu threshold correction is 20, and the Gaussian blur kernel size is 3×3.

[0067] Light stop parameters: angle threshold θ0 = 30°, distance threshold d0 = 10 pixels.

[0068] Snake model parameters: internal energy weight coefficients α=0.1, β=0.1, external energy weight coefficients λ=1.0, and the number of iterations is 100.

[0069] 2. Implementation Steps Details

[0070] (1) Image acquisition: Images of space debris illuminated by a 1064nm laser beam are acquired by an infrared guide star camera to obtain a sequence of images of different target scenes.

[0071] (2) Multi-level preprocessing: Opening operation (3×3 structuring element erosion + 3×3 structuring element dilation) is performed on the original image to remove background discrete noise; closing operation (3×3 structuring element dilation + 3×3 structuring element erosion) is performed to fill the small holes inside the contour; 5×5 window mean filtering is performed to suppress gray-level abrupt changes; after Otsu thresholding, correction is added to complete binarization; connected component analysis is performed to select the main contour with the largest area and remove small area noise; 3×3 Gaussian blur is used to smooth the edges, and then global thresholding binarization is performed to restore the contour.

[0072] Specifically, such as Figure 2 and Figure 3 As shown, Figure 2 This is a comparison image before and after multi-level preprocessing according to an embodiment of the present disclosure, used to demonstrate the effect of preprocessing on noise suppression and contour preservation. Figure 3 The images shown are laser beam profile extraction results under different Otsu thresholds according to embodiments of this disclosure, used to illustrate the necessity of threshold correction.

[0073] (3) Contour extraction: Initialize the Snake contour curve and set the energy function parameters; iteratively optimize the energy function to drive the contour to converge toward the edge of the beam and extract the initial contour; apply the aperture method (θ0=30°, d0=10 pixels) to perform piecewise fitting on the initial contour to obtain the closed straight line segment contour.

[0074] Specifically, such as Figure 4 and Figure 5 As shown, Figure 4 The diagram shows a comparison of the effects of different contour fitting methods according to embodiments of the present disclosure, used to illustrate the advantages of the aperture method. Figure 5 This describes the changes in the shape of the laser beam and the contour recognition process throughout the entire contour extraction process according to embodiments of this disclosure.

[0075] (4) Location point determination: Construct two types of structural feature lines based on the fitted contour; calculate the intersection of the feature lines to obtain candidate location points; determine the candidate location points as the tip position.

[0076] Specifically, such as Figure 6 and Figure 7 As shown, Figure 6 This is a schematic diagram of the distribution of various structural feature lines on the original image according to embodiments of the present disclosure, used to clarify the feature lines and finally select the feature point construction method. Figure 7 The results show the real-time identification of the optical tip position during actual testing in accordance with the embodiments of this disclosure.

[0077] 3. Experimental Results

[0078] The aforementioned method was deployed on a 70cm space debris laser ranging system to verify its application effect. The main focus was on laser beam tip recognition testing under conditions of high background noise in the laser beam image and difficulty in identifying the shape of the laser tip. Taking space debris target 23405 as an example, no echo signal was detected during observation by judging the laser tip. According to the recognition model, the laser beam tip deviated from the target by an average of 187.4 pixels in the x-direction and 107.58 pixels in the y-direction, with a total average distance of 216.76 pixels. After using the recognition model for assisted observation, the target echo signal was successfully measured.

[0079] Specifically, such as Figure 8 As shown, Figure 8 The target ranging result according to the embodiments of this disclosure is shown, wherein the area within the white frame represents the effective signal area.

[0080] Therefore, the infrared guide camera tip positioning method of the 1064nm laser ranging system provided in this disclosure addresses the problems of strong noise interference, beam contour distortion, and insufficient positioning accuracy and stability in the existing technology for infrared guide camera tip positioning. By adopting three core steps—multi-level image preprocessing, laser beam contour extraction, and tip positioning point determination—it achieves noise suppression and accurate preservation of beam contour, solving the core problems of strong noise and contour blurring in infrared guide camera images. It is a tip positioning method that balances noise suppression and contour preservation, has high positioning accuracy, and strong adaptability.

[0081] The infrared guide camera tip positioning method for the 1064nm laser ranging system disclosed herein employs a combination of the Snake model and the aperture method, which improves the accuracy and robustness of contour extraction. Quantitative analysis of feature line intersections clarifies the optimal positioning point, effectively avoiding beam distortion interference.

[0082] Experimental verification shows that the infrared guide star camera tip positioning method of the 1064nm laser ranging system provided in this disclosure effectively solves the positioning problem caused by strong noise and beam dispersion of the infrared guide star camera. It has high positioning accuracy and strong stability, is suitable for the complex observation scenarios of the 1064nm laser ranging system, significantly improves the reliability of laser debris ranging, and provides key technical support for space debris orbit monitoring.

[0083] This disclosure has now been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of this disclosure.

[0084] It should be noted that the above is merely an example of the "1064nm laser ranging system infrared guide camera tip positioning method" and should not be construed as a limitation on this patent invention. Any modifications, substitutions, or improvements to the 1064nm laser ranging system infrared guide camera tip positioning method using similar approaches should be included within the scope of protection of this invention.

[0085] Implementations not illustrated or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the elements above are not limited to the various specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0086] Of course, this disclosure may include other parts as needed, but since they are not relevant to the innovation of this disclosure, they will not be described in detail here.

[0087] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. However, this approach to disclosure should not be construed as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the aspects of the disclosure consist of fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the disclosure.

[0088] Furthermore, similar or identical parts are referred to by the same reference numerals in the accompanying drawings or description. Technical features in the various embodiments exemplified in the specification can be freely combined to form new solutions without conflict. Additionally, each claim can stand alone as an embodiment, or the technical features in the various claims can be combined to form new embodiments. Moreover, elements or implementations not shown or described in the drawings are forms known to those skilled in the art. Furthermore, while this document provides examples of parameters containing specific values, it should be understood that the parameters need not be exactly equal to the corresponding values, but can approximate the corresponding values ​​within acceptable error tolerances or design constraints.

[0089] Unless there are technical obstacles or contradictions, the various embodiments described above in this disclosure can be freely combined to form other embodiments, all of which are within the protection scope of this disclosure.

[0090] Although this disclosure has been described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of this disclosure and should not be construed as limiting the disclosure. The dimensions in the drawings are merely illustrative and should not be construed as limiting the disclosure.

[0091] While some embodiments of the general concept of this disclosure have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the general concept of this disclosure, the scope of which is defined by the claims and their equivalents.

[0092] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for positioning the optical tip of an infrared guide star camera in a 1064nm laser ranging system, characterized in that, include: S1: Perform multi-level preprocessing on the 1064nm laser beam image acquired by the infrared guide star camera; S2: Extract the laser beam contour from the preprocessed image; S3: Based on the contour extraction results, construct two types of structural feature lines and determine the intersection of the two types of structural feature lines as the optical tip positioning point.

2. The infrared guide star camera tip positioning method for the 1064nm laser ranging system according to claim 1, characterized in that, The multi-level preprocessing of the 1064nm laser beam image acquired by the infrared guide star camera in step S1 includes: The morphological opening and closing operation, mean filtering, modified Otsu threshold segmentation, main contour filtering and Gaussian blur processing are sequentially performed on the 1064nm laser beam image acquired by the infrared guide star camera to achieve noise suppression and beam contour preservation.

3. The infrared guide camera tip positioning method for the 1064nm laser ranging system according to claim 2, characterized in that, The aforementioned morphological opening and closing operations include: First, perform morphological opening operation, that is, perform erosion operation first and then dilation operation to remove discrete noise points in the background region; Then perform morphological closing operations, that is, first perform dilation operations and then perform erosion operations to fill the tiny closed areas inside the beam profile and regularize the profile shape.

4. The infrared guide camera tip positioning method for the 1064nm laser ranging system according to claim 2, characterized in that, The aforementioned mean filtering includes: Mean filtering is applied to the image to suppress abrupt changes in grayscale and reduce pixel value fluctuations, providing a stable pixel distribution basis for threshold segmentation.

5. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 2, characterized in that, The aforementioned execution of modified Otsu threshold segmentation includes: Based on the threshold initially determined by the Otsu method, a certain Otsu threshold correction amount is added according to the image features to complete image binarization, balancing noise suppression and beam information preservation. The Otsu threshold correction is 20, and the condition for completion is that the shape of the laser beam tip is clearly visible in the image.

6. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 2, characterized in that, The aforementioned main contour filtering includes: Based on the principle of pixel gray-level gradient abrupt change, white connected regions in the image are identified, the area of ​​each connected region is calculated, and the region with the largest area ratio is selected as the main contour of the laser beam, while small-area isolated bright spot noise is eliminated.

7. The method for positioning the optical tip of an infrared guide star camera in a 1064nm laser ranging system according to claim 2, characterized in that, The aforementioned Gaussian blurring process includes: The jagged artifacts on the contour edges are smoothed by weighted averaging using Gaussian blur kernels, and then the clear contours are restored by global thresholding binarization, taking into account both edge smoothness and original shape.

8. The infrared guide star camera tip positioning method for a 1064nm laser ranging system according to claim 2, characterized in that, The morphological opening and closing operation uses a 3×3 structuring element, the mean filtering window size is 5×5, and the Gaussian blur kernel size is 3×3.

9. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 1, characterized in that, Step S2, which involves extracting the laser beam contour from the preprocessed image, includes: The Snake active contour model is used to extract contours from the preprocessed image to obtain the initial contours. The initial contour is piecewise fitted using the aperture method to obtain the contour of closed straight line segments.

10. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 9, characterized in that, The method of using the Snake active contour model to extract contours from the preprocessed image to obtain initial contours includes: Initialize the Snake profile curve and set the energy function parameters; The energy function is iteratively optimized to drive the profile to converge toward the edge of the beam, thus obtaining the initial profile.

11. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 10, characterized in that, The energy function expression is: Where v(s)=(x(s),y(s)) is the parametric profile curve, E int For internal energy, E ext External energy; The iteratively optimized energy function drives the profile to converge toward the beam edge to obtain the initial profile. It is based on the energy minimization criterion and drives the profile to converge toward the beam edge through the synergistic effect of internal and external energy, thus accurately extracting the beam profile. The internal energy controls the smoothness and continuity of the profile, while the external energy drives the profile to converge toward the beam edge.

12. The infrared guide star camera tip positioning method for a 1064nm laser ranging system according to claim 9, characterized in that, The method of using the aperture method to segment and fit the initial contour to obtain the closed straight line segment contour includes: By setting an angle threshold θ0 and a distance threshold d0, the discrete contour points are piecewise fitted through distance and angle constraints, transforming the contour into closed straight line segments, thus completing the polygonal approximation of the contour and improving the accuracy of contour approximation.

13. The infrared guide star camera tip positioning method for a 1064nm laser ranging system according to claim 12, characterized in that, The angle threshold θ0 = 30°, and the distance threshold d0 = 10 pixels; The distance constraint conditions include: the Euclidean distance from the point to be determined to the vertex of the light bar is ≤ a preset distance threshold d0; The angle constraint conditions include: the angle between the reference direction of the aperture and the direction pointed to by the point to be determined is ≤ the preset angle threshold θ0; Only points that satisfy both constraints are considered points within the current line segment; otherwise, piecewise fitting is triggered.

14. The infrared guide camera tip positioning method for a 1064nm laser ranging system according to claim 1, characterized in that, The two types of structural feature lines mentioned in step S3 include: The overall fitted line of all sampling points; and The outermost contour fitting line that connects to the leftmost sampling point among all contour fitting lines.

Images