A Turntable Leveling Method Based on Optical Imaging

Abstract

This invention relates to a turntable leveling method based on optical imaging. A vertical collimator is positioned directly above the turntable to be leveled as a reference standard. A receiving focal plane is positioned on the turntable to reflect its horizontal position. The collimator illuminates the receiving focal plane, forming a crosshair image. The turntable is adjusted until the center of the crosshair image always coincides with the receiving focal plane, regardless of its rotation; at this point, the turntable can be considered level. To determine the center of the crosshair image, corner detection is used, allowing for more accurate center location and more precise adjustment. Most importantly, because the collimator is vertically positioned and the receiving focal plane is positioned relative to the turntable's rotation axis, precise leveling can still be achieved even if the turntable's surface is damaged.

Description

Technical Field

[0001] This invention relates to the field of leveling technology, and in particular to a turntable leveling method based on optical imaging. Background Technology

[0002] With the development of technology, turntables have been widely used in aviation, aerospace, optics, chip manufacturing and other fields. Turntable leveling is a very important indicator, especially for some high-precision equipment, where leveling accuracy directly affects the performance and overall precision of the equipment.

[0003] Existing turntable leveling methods employ either bubble leveling or electronic leveling. Both methods assume an ideal state where the turntable surface serves as a reference plane. A bubble level or electronic level is placed on the reference plane. Two orthogonal bubble levels or electronic levels are observed at the edge of the reference plane, and the turntable is rotated to adjust the leveling mechanism.

[0004] All of the above leveling methods require high precision of the turntable surface so that it can serve as a reference surface. The precision of the mounting surface of the bubble level or electronic level is also required to be high, as it needs to be resistant to deformation. When the turntable surface is damaged, it is impossible to level it accurately. Summary of the Invention

[0005] In view of this, it is necessary to provide a turntable leveling method based on optical imaging to solve the problem of how to accurately level the turntable when the surface is damaged.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] This invention provides a turntable leveling method based on optical imaging, comprising:

[0008] A parallel light tube is placed directly above the surface of the turntable to be leveled, and the emission direction of the parallel light tube is perpendicular to the horizontal plane.

[0009] A receiving focal plane is provided on the leveling turntable. The receiving focal plane is perpendicular to the rotation axis of the leveling turntable, and the center of the receiving focal plane coincides with the rotation axis of the leveling turntable. The receiving focal plane receives the light from the collimator and forms a cross-shaped reticle image.

[0010] The received image of the receiving focal plane is obtained, and corner detection is performed on the received image to obtain the coordinates of multiple imaging corner points;

[0011] The center coordinates of the crosshair image are obtained based on the coordinates of the plurality of imaging corner points;

[0012] Adjust the turntable to be leveled according to the center coordinates of the crosshair image until it reaches a horizontal position.

[0013] Furthermore, the step of acquiring the received image of the receiving focal plane and performing corner detection on the received image to obtain multiple imaging corner coordinates includes:

[0014] The received image is acquired and binarized to obtain a grayscale matrix.

[0015] A sliding calculation window is established, and the sliding calculation window is moved within the grayscale value matrix to obtain the horizontal grayscale change feature value and the vertical grayscale change feature value of each element in the grayscale value matrix;

[0016] Elements whose horizontal grayscale change feature values ​​and vertical grayscale change feature values ​​are both greater than a set change threshold are selected as imaging corner points, and the coordinates of multiple imaging corner points are obtained.

[0017] Furthermore, the receiving focal plane is the CCD focal plane of the photoelectric autocollimator; the process of acquiring the received image and binarizing the received image to obtain a grayscale matrix includes:

[0018] The received image is acquired, and the received image is filtered according to the color of the electric cross image on the CCD focal plane of the photoelectric autocollimator.

[0019] Based on the filtered received image, a grayscale image is obtained;

[0020] Binarize the grayscale image to obtain a grayscale value matrix.

[0021] Furthermore, obtaining the center coordinates of the crosshair image based on the coordinates of the plurality of imaging corner points includes:

[0022] Based on the coordinates of the multiple imaging corner points, the coordinates of the four center corner points are obtained;

[0023] The center coordinates of the crosshair image are obtained based on the coordinates of the four central corner points.

[0024] Furthermore, obtaining the coordinates of the four center corner points based on the coordinates of the plurality of imaging corner points includes:

[0025] Based on the coordinates of the imaging corner points, calculate the distance feature value for each imaging corner point, where the distance feature value is the sum of the distances between an imaging corner point and all other imaging corner points;

[0026] The multiple distance feature values ​​are sorted, and the imaging corner points corresponding to the four smallest distance feature values ​​are selected to obtain the four center corner points;

[0027] The coordinates of the four central corner points are obtained based on the four central corner points.

[0028] Furthermore, the center corner coordinates include horizontal and vertical coordinates, and obtaining the center coordinates of the crosshair image based on the four center corner coordinates includes:

[0029] Based on the coordinates of the four central corner points, the sum of the x-coordinates and the sum of the y-coordinates of the four central corner points are obtained;

[0030] The center coordinates of the crosshair image are obtained by summing the horizontal coordinates and summing the vertical coordinates.

[0031] Furthermore, the provision of a parallel light tube directly above the surface of the turntable to be leveled includes:

[0032] The collimator is configured such that its emitting end faces the turntable to be leveled, and the emitting end of the collimator is spaced apart from the turntable to be leveled.

[0033] A theodolite is placed between the emitting end of the collimator and the leveling turntable, and the theodolite is adjusted to a 90° reference. The reticle of the theodolite receives the light from the collimator to form a collimator cross image.

[0034] Adjust the collimator so that the crosshair image of the collimator coincides with the reference crosshair image of the theodolite.

[0035] Furthermore, the step of setting a receiving focal plane on the turntable to be leveled includes:

[0036] A photoelectric autocollimator is installed on the rotating shaft of the turntable to be leveled, so that the optical axis of the photoelectric autocollimator coincides with the rotation axis of the turntable to be leveled.

[0037] The leveling turntable is moved so that the light from the collimator shines onto the CCD focal plane of the photoelectric autocollimator to form a collimator cross image.

[0038] Wherein, the CCD focal plane of the photoelectric autocollimator is the receiving focal plane, and the center of the reference cross image on the CCD focal plane is the center of the receiving focal plane.

[0039] Furthermore, adjusting the turntable to be leveled based on the center coordinates of the crosshair image includes:

[0040] Determine whether the center coordinates of the crosshair image coincide with the center of the receiving focal plane. If yes, rotate the leveling turntable and re-determine. If no, adjust the leveling turntable.

[0041] Furthermore, the horizontal conditions include:

[0042] When the leveling turntable is rotated to any position, the center coordinates of the crosshair image coincide with the center of the receiving focal plane.

[0043] This invention provides a turntable leveling method based on optical imaging. A vertical collimator is placed directly above the turntable to be leveled as a reference standard. A receiving focal plane is set on the turntable to reflect its horizontal position. The receiving focal plane is perpendicular to the rotation axis of the turntable, and its center coincides with the rotation axis. The collimator illuminates the receiving focal plane, forming a crosshair image. The turntable is adjusted until the center of the crosshair image always coincides with the receiving focal plane, regardless of rotation. At this point, the turntable can be considered level. To determine the center of the crosshair image, corner detection is first used to identify the coordinates of the imaging corner points. Then, the center of the crosshair image is obtained from these corner point coordinates. This method allows for a more accurate identification of the crosshair image center, resulting in a more precise final adjustment. Most importantly, when making adjustments, the present invention can still achieve precise leveling even if the surface of the turntable is damaged because the collimator is set vertically and the position of the receiving focal plane is based on the rotation axis of the turntable to be leveled. Attached Figure Description

[0044] Figure 1 A flowchart illustrating an embodiment of the turntable leveling method based on optical imaging provided by the present invention;

[0045] Figure 2 A schematic diagram of the structure of an embodiment of the turntable leveling method based on optical imaging provided by the present invention during implementation;

[0046] Figure 3 for Figure 1 Step S103 is a method flowchart of an embodiment. Detailed Implementation

[0047] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0048] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0049] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0050] Combination Figure 1 As shown, the present invention provides a turntable leveling method based on optical imaging, comprising:

[0051] S101. A parallel light tube is installed directly above the surface of the turntable to be leveled, and the emission direction of the parallel light tube is perpendicular to the horizontal plane.

[0052] S102. A receiving focal plane is provided on the leveling turntable. The receiving focal plane is perpendicular to the rotation axis of the leveling turntable, and the center of the receiving focal plane coincides with the rotation axis of the leveling turntable. The receiving focal plane receives the light from the collimator and forms a cross-shaped reticle image.

[0053] S103. Obtain the received image of the receiving focal plane, and perform corner detection on the received image to obtain the coordinates of multiple imaging corner points;

[0054] S104. Obtain the center coordinates of the crosshair image based on the coordinates of the plurality of imaging corner points;

[0055] S105. Adjust the turntable to be leveled according to the center coordinates of the crosshair image until it reaches a horizontal condition.

[0056] This invention provides a turntable leveling method based on optical imaging. A vertical collimator is placed directly above the turntable to be leveled as a reference standard. A receiving focal plane is positioned on the turntable to reflect its horizontal position. The receiving focal plane is perpendicular to the rotation axis of the turntable, and its center coincides with the rotation axis. The collimator illuminates the receiving focal plane, forming a crosshair image. The turntable is adjusted until the center of the crosshair image and the receiving focal plane always coincide, regardless of rotation. At this point, the turntable is considered level. To determine the center of the crosshair image, focus detection is first used to identify the coordinates of the imaging corner points. Then, the center of the crosshair image is obtained from these coordinates. This allows for a more accurate identification of the crosshair image center, resulting in a more precise adjustment. Most importantly, because the collimator is vertically positioned and the receiving focal plane is based on the rotation axis of the turntable, precise leveling can still be achieved even if the surface of the turntable is damaged.

[0057] Specifically, as a preferred embodiment, step S101 in this embodiment, setting a parallel light tube directly above the surface of the turntable to be leveled, specifically includes:

[0058] The collimator is configured such that its emitting end faces the turntable to be leveled, and the emitting end of the collimator is spaced apart from the turntable to be leveled.

[0059] A theodolite is placed between the emitting end of the collimator and the leveling turntable, and the theodolite is adjusted to a 90° reference. The reticle of the theodolite receives the light from the collimator to form a collimator cross image.

[0060] Adjust the collimator so that the crosshair image of the collimator coincides with the reference crosshair image of the theodolite.

[0061] In a preferred embodiment, step S102 of this embodiment, setting a receiving focal plane on the turntable to be leveled, specifically includes:

[0062] A photoelectric autocollimator is installed on the rotating shaft of the turntable to be leveled, so that the optical axis of the photoelectric autocollimator coincides with the rotation axis of the turntable to be leveled.

[0063] The leveling turntable is moved so that the light from the collimator shines onto the CCD focal plane of the photoelectric autocollimator to form a collimator cross image.

[0064] Wherein, the CCD focal plane of the photoelectric autocollimator is the receiving focal plane, and the center of the reference cross image on the CCD focal plane is the center of the receiving focal plane.

[0065] It is understandable that other existing devices can be used in practice, as long as the device has a plane capable of receiving light and the received image can be acquired by a computer. On the other hand, the methods for fixing the collimator and the receiving focal plane in this embodiment are existing technologies that those skilled in the art can conceive of. Furthermore, for ease of understanding, the present invention provides a more preferred embodiment for more detailed explanation of steps S101-S102:

[0066] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of the optical imaging turntable leveling method provided by the present invention during implementation. It includes a turntable to be leveled 1, a collimator 2, a collimator fixing fixture 3, a photoelectric autocollimator 4, a photoelectric autocollimator fixing fixture 5, two dial indicators 6, and a dial indicator fixing fixture 7. The collimator 2 and the photoelectric autocollimator 4 are installed according to the following steps:

[0067] a) Using the collimator fixing fixture 3, fix the collimator 2 directly above the turntable 1 to be leveled. The distance between the light outlet of the collimator 2 and the table surface is 600mm, and there is sufficient operating space above the turntable.

[0068] (b) Establishing a 90° reference with collimator 2: First, set up the theodolite on the leveling turntable 1 and level it. Use the theodolite's 90° reference to calibrate collimator 2. The theodolite and collimator 2 are aligned. Light is emitted from collimator 2, and the crosshair image of collimator 2 is focused onto the theodolite's reticle. The theodolite's reticle receives the light from collimator 2, forming a crosshair image. Observing through the theodolite eyepiece, using the theodolite's 90° reference, adjust collimator 2 until its crosshair image coincides with the theodolite's reference crosshair image. At this point, the 90° reference for collimator 2 is established, meaning the light emitted by collimator 2 is perpendicular to the horizontal plane.

[0069] c) Remove the theodolite and move the leveling turntable 1 horizontally so that the optical axis of the collimator 2 is roughly aligned with the center of the rotation axis of the leveling turntable 1.

[0070] d) Set the photoelectric autocollimator 4 on the rotation center of the turntable 1 to be leveled using the photoelectric autocollimator fixing fixture 5. Use a dial indicator 6 or a lever micrometer to mark the outer circle of the photoelectric autocollimator 4. In this embodiment, two dial indicators 6 are used, fixed by the dial indicator fixing fixture 7. Adjust the position of the photoelectric autocollimator 4 until the dial indicator 6 runs out of 0 (or other within the required range) when the turntable rotates. At this point, it can be considered that the rotation axis of the turntable 1 to be leveled and the mechanical axis of the photoelectric autocollimator 4 (i.e., the center of the receiving focal plane) have been aligned.

[0071] e) The optical axis of the photoelectric autocollimator 4 is coincident with the mechanical axis. As can be seen from step d), the rotation axis of the turntable can be derived from the optical axis of the photoelectric autocollimator 4.

[0072] f) Light is emitted from collimator 2 and observed through photoelectric autocollimator 4. The cross image formed by the light from collimator 2 is focused onto the CCD focal plane of photoelectric autocollimator 4, and the cross image of collimator 2 is displayed in the image display area of ​​the software interface.

[0073] g) Move the turntable so that the cross image of the collimator 2 coincides with the electric cross image of the photoelectric autocollimator 4.

[0074] Similarly, it is easy to understand that the details not described in the above process are all existing technologies and will not be elaborated on in this article.

[0075] After setting up the collimator and receiving focal plane through the above process, the leveling turntable can be adjusted. During the adjustment process, it is necessary to obtain the center of the crosshair image. However, in reality, due to environmental and other factors, the light shining on the receiving focal plane may not form a regular and complete crosshair image. In addition, the thickness of the crosshair image may affect human judgment. Therefore, the corner detection method is used in this invention to obtain the center of the crosshair image in order to improve the accuracy of judgment.

[0076] Specifically, in combination Figure 3 As shown, in a preferred embodiment, step S103 of this embodiment, acquiring the received image of the receiving focal plane and performing corner detection on the received image to obtain the coordinates of multiple imaging corner points, specifically includes:

[0077] S301. Acquire the received image and perform binarization processing on the received image to obtain a grayscale matrix.

[0078] S302. Establish a sliding calculation window and move the sliding calculation window in the gray value matrix to obtain the horizontal gray value change feature value and the vertical gray value change feature value of each element in the gray value matrix;

[0079] S303. Select elements whose horizontal grayscale change feature values ​​and vertical grayscale change feature values ​​are both greater than a set change threshold as imaging corner points, and obtain the coordinates of multiple imaging corner points.

[0080] In a specific embodiment, step S301, acquiring the received image and binarizing the received image to obtain a grayscale matrix, specifically includes:

[0081] The received image is acquired, and the received image is filtered according to the color of the electric cross image on the CCD focal plane of the photoelectric autocollimator.

[0082] Based on the filtered received image, a grayscale image is obtained;

[0083] Binarize the grayscale image to obtain a grayscale value matrix.

[0084] In this embodiment, because an opto-autocollimator is used, the received image includes not only the collimator crosshair image but also the electrical crosshair image inherent to the opto-autocollimator. Therefore, before corner detection, filtering is required to remove the electrical crosshair image from the image, retaining only the collimator crosshair image. Filtering the electrical crosshair image can be done using any existing method; for example, if the electrical crosshair image is green, a green channel exclusion method can be used to filter it out. After filtering, denoising is performed to obtain the brightness of each pixel to get a grayscale image. Binarization then yields a grayscale matrix, where each element represents a pixel in the received image, and the position of that element in the matrix is ​​the coordinate of the corresponding pixel. The specific implementation of the above process is existing technology and will not be elaborated upon in this paper.

[0085] In this embodiment, steps S302-S303 involve detecting imaging corners using the Harris corner detection method. This involves establishing a sliding calculation window, which moves within the grayscale matrix to calculate the grayscale changes of each pixel in different directions, thereby determining whether it is a corner. It's worth noting that since cross-shaped reticle images are generally horizontally and vertically aligned, this embodiment only requires calculating the grayscale changes in the horizontal and vertical directions for each pixel using the sliding calculation window. Specifically, in this embodiment, the horizontal grayscale change feature value characterizes the grayscale change of a pixel in the horizontal direction, and the vertical grayscale change feature value characterizes the grayscale change of a pixel in the vertical direction. When both the horizontal and vertical grayscale change feature values ​​of a pixel are greater than a set threshold, the pixel corresponding to that element can be considered an imaging corner of the cross-shaped reticle image, and the location of that pixel is its imaging corner coordinates.

[0086] In a preferred embodiment, step S104 of this embodiment, obtaining the center coordinates of the crosshair image based on the coordinates of the plurality of imaging corner points, specifically includes:

[0087] Based on the coordinates of the multiple imaging corner points, the coordinates of the four center corner points are obtained;

[0088] The center coordinates of the crosshair image are obtained based on the coordinates of the four central corner points.

[0089] It is understandable that the imaging corner points of a cross-shaped reticle are the intersections of the two sides of the cross shape. A cross-shaped reticle can be considered as composed of two line segments with a certain width. Corner points can be formed at the ends of the two line segments and at their intersection; these are the imaging corner points of the cross-shaped reticle. The corner points formed by the edge lines at the ends of the line segments are called edge corner points, and the corner points formed by the edge lines at the intersection of the line segments are called center corner points. In this embodiment, four center corner points are selected from multiple imaging corner points, and the center coordinates of the cross-shaped reticle are determined based on the coordinates of the center corner points.

[0090] Specifically, as a preferred embodiment, the step of obtaining the coordinates of the four center corner points based on the coordinates of the plurality of imaging corner points in this embodiment specifically includes:

[0091] Based on the coordinates of the imaging corner points, calculate the distance feature value for each imaging corner point, where the distance feature value is the sum of the distances between an imaging corner point and all other imaging corner points;

[0092] The multiple distance feature values ​​are sorted, and the imaging corner points corresponding to the four smallest distance feature values ​​are selected to obtain the four center corner points;

[0093] The coordinates of the four central corner points are obtained based on the four central corner points.

[0094] The above process determines the center corner point by the distance between the imaging corner points. For a certain imaging corner point, the sum of the distances from that imaging corner point to each of the remaining imaging corner points is the distance feature value of that imaging corner point. The magnitude of the distance feature value can reflect its position among all corner points to a certain extent. Obviously, the four imaging corner points with the smallest distance feature values ​​are the center corner points.

[0095] The coordinates of the central corner points are two-dimensional coordinates of the plane, including the x-coordinate and y-coordinate. Therefore, further, the process described above, obtaining the center coordinates of the crosshair image based on the coordinates of the four central corner points, includes:

[0096] Based on the coordinates of the four central corner points, the sum of the x-coordinates and the sum of the y-coordinates of the four central corner points are obtained;

[0097] The center coordinates of the crosshair image are obtained by summing the horizontal coordinates and summing the vertical coordinates.

[0098] The above process is the problem of calculating the center coordinates of four known coordinate points. In actual implementation, in addition to the above process, other existing methods can also be used for calculation.

[0099] After obtaining the center coordinates using the above method, the leveling turntable can be precisely adjusted. In a preferred embodiment, step S105, adjusting the leveling turntable according to the center coordinates of the crosshair image until a horizontal condition is met, specifically includes:

[0100] Determine whether the center coordinates of the crosshair image coincide with the center of the receiving focal plane. If yes, rotate the leveling turntable and re-determine. If no, adjust the leveling turntable.

[0101] The methods for adjusting the turntable to be leveled in the above process include moving the turntable, changing the tilt angle of the turntable, etc. The specific operation method depends on the specific structure of the turntable to be leveled, and all of them are methods that can be conceived by those skilled in the art. The horizontal condition mentioned in the above process specifically includes: when the turntable to be leveled is rotated to any position, the center coordinates of the crosshair image coincide with the center of the receiving focal plane.

[0102] This invention provides a turntable leveling method based on optical imaging. A vertical collimator is placed directly above the turntable to be leveled as a reference standard. A receiving focal plane is set on the turntable to reflect its horizontal position. The receiving focal plane is perpendicular to the rotation axis of the turntable, and its center coincides with the rotation axis. The collimator illuminates the receiving focal plane, forming a crosshair image. The turntable is adjusted until the center of the crosshair image always coincides with the receiving focal plane, regardless of rotation. At this point, the turntable can be considered level. To determine the center of the crosshair image, corner detection is first used to identify the coordinates of the imaging corner points. Then, the center of the crosshair image is obtained from these corner point coordinates. This method allows for a more accurate identification of the crosshair image center, resulting in a more precise final adjustment. Most importantly, when making adjustments, the present invention can still achieve precise leveling even if the surface of the turntable is damaged because the collimator is set vertically and the position of the receiving focal plane is based on the rotation axis of the turntable to be leveled.

[0103] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optical imaging based turntable leveling, the method comprising: The application relates to a method for leveling a turntable, comprising the following steps: a parallel light tube is arranged directly above the surface of the turntable to be leveled, and the emission direction of the parallel light tube is perpendicular to a horizontal plane; a receiving focal plane is arranged on the turntable to be leveled, the receiving focal plane is perpendicular to the rotation axis of the turntable to be leveled, the center of the receiving focal plane coincides with the rotation axis of the turntable to be leveled, the receiving focal plane receives the light rays of the parallel light tube and forms a cross reticle image; receiving imaging of the receiving focal plane is acquired, and corner point detection is performed on the receiving imaging to obtain a plurality of imaging corner point coordinates; the center coordinates of the cross reticle image are obtained according to the plurality of imaging corner point coordinates; the turntable to be leveled is adjusted according to the center coordinates of the cross reticle image until a horizontal condition is reached; the step of arranging the receiving focal plane on the turntable to be leveled comprises the following steps: an optoelectronic autocollimator is arranged on the rotation shaft of the turntable to be leveled, so that the optical axis of the optoelectronic autocollimator coincides with the rotation axis of the turntable to be leveled; the turntable to be leveled is translated so that the light rays of the parallel light tube irradiate the CCD focal plane of the optoelectronic autocollimator to form a parallel light tube cross image; wherein the CCD focal plane of the optoelectronic autocollimator is the receiving focal plane, and the center of the reference cross image on the CCD focal plane is the center of the receiving focal plane.

2. The optical imaging based turntable leveling method of claim 1, wherein, the step of acquiring the receiving imaging of the receiving focal plane and performing corner point detection on the receiving imaging to obtain a plurality of imaging corner point coordinates comprises the following steps: the receiving imaging is acquired, and binary processing is performed on the receiving imaging to obtain a gray value matrix; a sliding calculation window is established, and the sliding calculation window is moved in the gray value matrix to obtain the horizontal gray level variation characteristic value and the vertical gray level variation characteristic value of each element in the gray value matrix; elements with both the horizontal gray level variation characteristic value and the vertical gray level variation characteristic value greater than a set variation threshold value are selected as imaging corner points, and a plurality of imaging corner point coordinates are obtained.

3. The optical imaging based turntable leveling method of claim 2, wherein, the receiving focal plane is the CCD focal plane of the optoelectronic autocollimator; the step of acquiring the receiving imaging and performing binary processing on the receiving imaging to obtain a gray value matrix comprises the following steps: the receiving imaging is acquired, and filtering is performed on the receiving imaging according to the color of the electric cross image on the CCD focal plane of the optoelectronic autocollimator; a gray image is obtained according to the filtered receiving imaging; the gray image is binarized to obtain a gray value matrix.

4. The optical imaging based turntable leveling method of claim 1, wherein, the step of obtaining the center coordinates of the cross reticle image according to the plurality of imaging corner point coordinates comprises the following steps: four center corner point coordinates are obtained according to the plurality of imaging corner point coordinates; the center coordinates of the cross reticle image are obtained according to the four center corner point coordinates.

5. The optical imaging based turntable leveling method of claim 4, wherein, the step of obtaining four center corner point coordinates according to the plurality of imaging corner point coordinates comprises the following steps: distance characteristic values of each imaging corner point are calculated according to the imaging corner point coordinates, the distance characteristic value being the sum of the distances of one imaging corner point from all other imaging corner points; the plurality of distance characteristic values are sorted, and four center corners corresponding to the four smallest distance characteristic values are selected to obtain four center corner points. According to the four center angle points, four center angle point coordinates are obtained.

6. The optical imaging based turntable leveling method of claim 4, wherein, The center angle point coordinates include horizontal coordinates and vertical coordinates, and the center coordinates of the cross reticle image are obtained according to the four center angle point coordinates, including: According to the four center angle point coordinates, the sum of the horizontal coordinates and the sum of the vertical coordinates of the four center angle points are obtained; According to the sum of the horizontal coordinates and the sum of the vertical coordinates, the center coordinates of the cross reticle image are obtained.

7. The optical imaging based turntable leveling method of claim 1, wherein, The parallel light tube is arranged directly above the surface of the turntable to be leveled, including: The parallel light tube is arranged so that the emission end of the parallel light tube faces the turntable to be leveled, and the emission end of the parallel light tube is arranged at a distance from the turntable to be leveled; A theodolite is arranged between the emission end of the parallel light tube and the turntable to be leveled, and the theodolite is adjusted to a 90° reference, and the reticle plate of the theodolite receives the light of the parallel light tube to form a parallel light tube cross image; The parallel light tube is adjusted so that the parallel light tube cross image and the reference cross image of the theodolite coincide.

8. The optical imaging based turntable leveling method of claim 1, wherein, The center coordinates of the cross reticle image are obtained according to the center coordinates of the cross reticle image, and the turntable to be leveled is adjusted, including: It is judged whether the center coordinates of the cross reticle image coincide with the center of the receiving focal plane, if yes, the turntable to be leveled is rotated and re-judged, if not, the turntable to be leveled is adjusted.

9. The optical imaging based turntable leveling method of claim 8, wherein, The horizontal condition includes: When the turntable to be leveled is rotated to any position, the center coordinates of the cross reticle image coincide with the center of the receiving focal plane.

Images