Total station long-focus camera internal parameter and installation angle calibration method and device and medium

Abstract

This invention discloses a method, device, and medium for calibrating the intrinsic parameters and installation angle of a total station's telephoto camera. The invention captures an observation image of a calibration board using a telephoto camera and extracts the first position information of the target point in the image coordinate system from the image. This obtains the relevant position information of the total station and the telephoto camera. Based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera, second position information is determined. The second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system. This simplifies the process by allowing shooting at a single measurement station instead of multiple stations. The reprojection error is determined based on the difference between the first and second position information. Optimization processing is performed based on the reprojection error to determine the target parameters of the telephoto camera. This allows for the simultaneous acquisition of the target intrinsic parameters and the target installation angle without requiring two-step calibration, thus improving calibration efficiency.

Description

Technical Field

[0001] This invention relates to the field of calibration, and in particular to a method, apparatus and medium for calibrating the intrinsic parameters and installation angle of a total station's telephoto camera. Background Technology

[0002] A camera is mounted on the line of sight of the total station, with a rigid connection between the camera and the total station. This ensures that the camera's field of view remains consistent with the total station's eyepiece field of view regardless of the rotation of the total station's horizontal axis and line of sight. The camera's field of view is significantly larger than the eyepiece's (1.5°), allowing for rough aiming of target points or stakeout points using the camera's image, followed by fine aiming using the eyepiece. This improves the operator's experience and work efficiency.

[0003] In actual camera module installation, there is an installation angle error of about 1°. To achieve centimeter-level coarse aiming, high-precision camera intrinsic parameters and installation angles need to be calibrated. Current solutions generally use a two-step calibration method: first, calibrate the camera's intrinsic parameters, then calibrate the camera's installation angle. Furthermore, it is necessary to calibrate the positional and angular offsets, requiring multiple measurement stations to enhance the strength of the calibration model. This process is cumbersome and inefficient. Summary of the Invention

[0004] In view of this, in order to solve at least one of the above-mentioned technical problems, the purpose of this invention is to provide a method, apparatus, equipment and storage medium for calibrating the intrinsic parameters and installation angle of a total station telephoto camera, simplifying the calibration process and improving calibration efficiency.

[0005] This invention provides a method for calibrating the intrinsic parameters and installation angle of a total station's telephoto camera, including:

[0006] The observation image of the calibration board is captured by a telephoto camera, and the first position information of the target point in the image coordinate system is extracted from the observation image.

[0007] Obtain the relevant position information of the total station and the telephoto camera, and determine the second position information based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera; the second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system;

[0008] The reprojection error is determined based on the difference between the first location information and the second location information. The reprojection error is then used for optimization processing to determine the target parameters of the telephoto camera. The target parameters include the target intrinsic parameters and the target installation angle.

[0009] Further, extracting the first position information of the target point in the image coordinate system from the observed image includes:

[0010] Select the corner points of the calibration board from the observed images as target points;

[0011] Obtain the first position information of the target point in the image coordinate system.

[0012] Furthermore, the relevant location information includes the first transformation matrix from the total station's carrier coordinate system to the navigation coordinate system, the first coordinates of the total station's center in the navigation coordinate system, the lever arm value between the telephoto camera and the total station's center in the carrier coordinate system, and the second coordinates of the target point in the navigation coordinate system.

[0013] The step of determining the second location information based on the relevant location information and the camera intrinsic parameter matrix of the telephoto camera includes:

[0014] Based on the first coordinates, the first transformation matrix, the lever arm value, the transformation matrix to be solved, and the second coordinates, a first position representation is calculated; the transformation matrix to be solved is the transformation matrix from the camera coordinate system to the carrier coordinate system, and the first position representation is the vector from the telephoto camera to the target point in the camera coordinate system.

[0015] The second position representation is calculated based on the first position representation and the preset distortion formula; the second position representation is the vector from the telephoto camera to the target point in the camera coordinate system after considering distortion.

[0016] The second position information is obtained based on the second position representation and the camera intrinsic parameter matrix.

[0017] Further, the step of calculating the first position representation based on the first coordinates, the first transformation matrix, the lever arm value, the transformation matrix to be solved, and the second coordinates includes:

[0018] Calculate the product of the first transformation matrix and the lever value, and obtain the third coordinate of the telephoto camera's optical center in the navigation coordinate system based on the sum of the product and the first coordinate.

[0019] Calculate the difference between the second coordinate and the third coordinate, and calculate the first position representation based on the difference, the transformation matrix to be solved, and the first transformation matrix.

[0020] Furthermore, the second position specifically indicates:

[0021]

[0022] in, The second position represents the distortion parameter to be solved, and the first position represents the... T is the transpose, and X, Y, and Z are the components of different coordinate axes.

[0023] Furthermore, obtaining the second position information based on the second position representation and the camera intrinsic parameter matrix includes:

[0024] Based on the camera intrinsic parameter matrix, the second position representation is projected onto the image coordinate system to obtain the second position information; the second position information is specifically as follows:

[0025]

[0026] The second position indicates T is the transpose, f x Let f be the focal length of the telephoto camera with respect to the X-axis. y Let c be the focal length of the telephoto camera about the Y-axis, which needs to be solved. x and c y These are the X-axis and Y-axis coordinates of the principal point of the telephoto camera, respectively. These are the components of different coordinate axes after considering distortion.

[0027] Furthermore, the optimization process based on the reprojection error to determine the target parameters of the telephoto camera includes:

[0028] Construct a least-squares optimization problem model based on the reprojection error;

[0029] The target parameters of the telephoto camera are obtained by solving the least squares optimization problem model using the LM algorithm.

[0030] The target intrinsic parameters include the target value of the focal length of the telephoto camera on the X-axis to be solved in the camera intrinsic parameter matrix, the target value of the focal length of the telephoto camera on the Y-axis to be solved, the target value of the distortion parameter to be solved in the second position information, and the target value of the transformation matrix to be solved. The target value of the transformation matrix to be solved includes the target mounting angle.

[0031] This invention also provides a device for calibrating the intrinsic parameters and mounting angle of a total station's telephoto camera, comprising:

[0032] The extraction module is used to capture observation images of the calibration board using a telephoto camera and extract the first position information of the target point in the image coordinate system from the observation images;

[0033] The determination module is used to acquire the relevant position information of the total station and the telephoto camera, and determine the second position information based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera; the second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system;

[0034] The processing module is used to determine the reprojection error based on the difference between the first position information and the second position information, perform optimization processing based on the reprojection error, and determine the target parameters of the telephoto camera; the target parameters include target intrinsic parameters and target installation angle.

[0035] This invention also provides a calibration device for the intrinsic parameters and installation angle of a total station's telephoto camera. The calibration device includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set, or an instruction set. The at least one instruction, the at least one program, the code set, or the instruction set are loaded and executed by the processor to implement the method.

[0036] This invention also provides a computer-readable storage medium storing at least one instruction, at least one program, a code set, or an instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the method.

[0037] The beneficial effects of this invention are:

[0038] The calibration board is observed using a telephoto camera, and the first position information of the target point in the image coordinate system is extracted from the observed image. Relevant position information of the total station and the telephoto camera is obtained. Based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera, second position information is determined. The second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system. This process simplifies the process by allowing shooting at a single measurement station instead of multiple stations. The reprojection error is determined based on the difference between the first and second position information. Optimization processing is performed based on the reprojection error to determine the target parameters of the telephoto camera. This allows for the simultaneous acquisition of target intrinsic parameters and target installation angle without requiring two-step calibration, thus improving calibration efficiency.

[0039] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the steps of the method for calibrating the intrinsic parameters and installation angle of the long-focal-length camera of the total station according to the present invention;

[0041] Figure 2 This is a schematic diagram illustrating the geometric relationship between the carrier coordinate system and the camera coordinate system of a total station according to a specific embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram of the observed image according to a specific embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0044] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0045] 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 this application. 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.

[0046] In existing technologies, to accommodate the long-distance measurement applications of total stations, a telephoto camera is typically installed on the total station. However, the field of view of a telephoto camera is generally small, typically 10°–15°. For calibration methods based on markers to construct an effective closed-form solution, the camera needs to rotate 45° on both the x and y axes when capturing the image. This is easily achieved with wide-angle or ultra-wide-angle cameras, but very difficult for telephoto cameras. If a checkerboard calibration board measuring 0.6m wide and 0.8m long is used, to ensure the entire calibration board is visible in the camera and occupies approximately 40% of the field of view in the image, the distance between the checkerboard calibration board and the telephoto camera would be approximately 7–10m. Considering the requirement for the camera to rotate 45° on both the x and y axes, the calibration area would need at least 7x7x7m of space. For typical indoor floors, a 7-meter ceiling height is extremely demanding. Therefore, traditional calibration of telephoto cameras has always been conducted outdoors. However, outdoor conditions are easily affected by factors such as lighting. In strong light, the camera may overexpose, significantly reducing the accuracy of the recognized checkerboard pattern. In weak light, automatic checkerboard recognition becomes very difficult, impacting work efficiency. These stringent conditions can easily affect calibration accuracy. Furthermore, active vision-based calibration methods require a precise control platform, resulting in high costs. While camera self-calibration methods offer high flexibility, they generally have lower accuracy and poor robustness.

[0047] like Figure 1 As shown, this embodiment of the invention provides a method for calibrating the intrinsic parameters and installation angle of a total station's telephoto camera, including steps S100-S300:

[0048] S100: Capture the observation image of the calibration board using a telephoto camera, and extract the first position information of the target point in the image coordinate system from the observation image.

[0049] It should be noted that in this embodiment of the invention, the navigation coordinate system is denoted as the n-system, the camera coordinate system as the c-system, and the carrier coordinate system of the total station when the horizontal angle is 0° and the vertical angle is 90° is denoted as the b-system; the camera mentioned in this embodiment of the invention is a telephoto camera. Figure 2 The figure shows the geometric relationship between the total station's carrier coordinate system and the camera coordinate system.

[0050] Specifically, taking a calibration board as a chessboard with grid lines as an example, first, a calibration site is set up. A chessboard of appropriate size is mounted on the wall as the calibration board. Based on the actual focal length and field of view of the telephoto camera, the distance between the camera and the chessboard grid is adjusted. When the chessboard grid can be completely observed in the image and occupies approximately 40% of the field of view, a measurement station is set up and its position is measured. Then, a total station is set up at the measurement station, the base is leveled, and the station is oriented. The horizontal axis and line of sight knobs of the total station are adjusted to capture the observation image of the calibration board through the telephoto camera. It should be noted that the number of observation images can be several, and the area where the calibration board is located will be different in each observation image. Figure 3 As shown, this example uses nine observation images.

[0051] It should be noted that the navigation coordinate system described in this embodiment of the invention can assume a north direction, differing from the actual navigation coordinate system by a heading angle. Subsequent calibrations based on this assumed north-oriented navigation coordinate system are unaffected by the assumed north direction, and the calibrated target intrinsic parameters and target installation angles are not affected by this assumed north direction. The calibration site only needs to be set up once for the calibration of a large number of total station telephoto cameras' intrinsic parameters and installation angles, which is convenient, quick, and improves calibration efficiency.

[0052] Optionally, step S100, which involves extracting the first position information of the target point in the image coordinate system from the observed image, includes steps S110-S120:

[0053] S110. Select the corner point of the calibration plate from the observed image as the target point.

[0054] S120. Obtain the first position information of the target point in the image coordinate system.

[0055] Optionally, in this embodiment of the invention, the corner points of the calibration board, i.e., the checkerboard, are used as target points to obtain the first position information of the target points in the image coordinate system. It should be noted that the number of corner points can be one or more.

[0056] S200: Obtain the relevant position information of the total station and the telephoto camera, and determine the second position information based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera.

[0057] In this embodiment of the invention, the second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system.

[0058] Optionally, in this embodiment of the invention, the relevant location information includes, but is not limited to, the first transformation matrix from the total station's carrier coordinate system to the navigation coordinate system. The first coordinate of the total station center in the navigation coordinate system Lever value between the telephoto camera and the center of the total station in the carrier coordinate system The second coordinate of the target point in the navigation coordinate system The principal point of the telephoto camera has the following X-axis coordinate value c. x The Y-coordinate value c of the principal point of the telephoto camera. y c x c is half the length of the observed image. y It is half the width of the observed image. Wherein, the second coordinate... Measurements were taken using a total station. It should be noted that, in this embodiment of the invention, the three-dimensional vector (coordinates) are denoted as follows: In the form of f, the superscript n indicates that the three-dimensional vector is represented in the n-system, the subscript n is the starting point of the vector, and f is the ending point of the vector. The first transformation matrix is... The lever arm value can be obtained by converting the horizontal and vertical angles output by the total station. Use structure values.

[0059] Optionally, step S200 includes steps S210-S230:

[0060] S210. Based on the first coordinate, the first transformation matrix, the lever arm value, the transformation matrix to be solved, and the second coordinate, the first position representation is calculated.

[0061] In this embodiment of the invention, the transformation matrix to be solved is the transformation matrix from the camera coordinate system to the carrier coordinate system, and the first position is represented by the vector from the telephoto camera to the target point in the camera coordinate system.

[0062] Specifically, step S210 includes steps S2101-S2102:

[0063] S2101. Calculate the product of the first transformation matrix and the lever arm value, and obtain the third coordinate of the telephoto camera's optical center in the navigation coordinate system based on the sum of the product and the first coordinate.

[0064] Third coordinate The specific calculation formula is as follows:

[0065]

[0066] S2102. Calculate the difference between the second coordinate and the third coordinate. Based on the difference, the transformation matrix to be solved, and the first transformation matrix, calculate the first position representation.

[0067] The specific calculation formula is as follows:

[0068]

[0069] in, Let T be the first position, and T be the transpose. Let be the transformation matrix to be solved.

[0070] S220. Based on the first position representation and the preset distortion formula, the second position representation is calculated; the second position representation is the representation of the vector from the telephoto camera to the target point in the camera coordinate system after considering distortion.

[0071] Alternatively, the distortion formula is:

[0072]

[0073] Where (xy) is the ideal coordinate point, (x d y d Let be the coordinates of the point after considering distortion, k1, k2, and k3 be the radial distortion parameters, p1 and p2 be the tangential distortion parameters, and r be the radius. It should be noted that distortion becomes increasingly pronounced as the camera's focal length decreases. Since the total station uses a telephoto camera, the distortion is relatively small; therefore, tangential distortion can be disregarded, and only the first-order radial distortion needs to be considered. This yields the preset distortion formula:

[0074]

[0075] In this embodiment of the invention, the first position indicates It can be written as Where T is the transpose, and X, Y, and Z are the components of different coordinate axes, based on formula (4) and the first position representation. We can obtain that the second position represents, specifically:

[0076]

[0077] in, This is indicated by the second position, and It can be represented as These are the components of different coordinate axes after considering distortion, and k1 is the radial distortion parameter (denoted as the distortion parameter to be solved).

[0078] S230. Based on the second position representation and the camera intrinsic parameter matrix, the second position information is obtained.

[0079] In this embodiment of the invention, the camera intrinsic parameter matrix is ​​preset, and the camera intrinsic parameter matrix K is:

[0080]

[0081] Among them, f x Let f be the focal length of the telephoto camera with respect to the X-axis. y Let c be the focal length of the telephoto camera about the Y-axis, which needs to be solved. x and c yThese are the X-axis and Y-axis coordinates of the principal point of the telephoto camera, respectively. In this embodiment of the invention, c x Let c be half the length of the observed image. y Set it to half the width of the observed image.

[0082] Specifically, based on the camera intrinsic parameter matrix, the second position representation is projected onto the image coordinate system to obtain the second position information p (or the position representation of pixel p):

[0083]

[0084] It should be noted that the second position information p represents a pixel in the observed image in the image coordinate system, and this pixel p can be denoted as p = [uv 1]. T (u is the coordinate of the x-axis in the image coordinate system, and v is the coordinate of the y-axis in the image coordinate system).

[0085] S300: Determine the reprojection error based on the difference between the first position information and the second position information, perform optimization processing based on the reprojection error, and determine the target parameters of the telephoto camera.

[0086] In this embodiment of the invention, the reprojection error is: p i This is the second location information corresponding to the i-th target point. This represents the first location information corresponding to the i-th target point.

[0087] Specifically, optimization processing is performed based on the reprojection error to determine the target parameters of the telephoto camera, including steps S310-S320:

[0088] S310. Construct a least-squares optimization problem model based on the reprojection error.

[0089] Specifically, m is the number of i, and the least squares optimization problem model E is:

[0090]

[0091] Where, r c It is the reprojection error, where r is short for residual and c is short for camera.

[0092] S320. Solve the least squares optimization problem model using the LM algorithm to obtain the target parameters of the telephoto camera.

[0093] In this embodiment of the invention, after constructing the least squares optimization problem model, the Levenberg-Marquardt method (LM algorithm) is used to solve the least squares optimization problem, thereby obtaining the target parameters of the telephoto camera. In this embodiment, the target parameters include target intrinsic parameters and target mounting angle. The target intrinsic parameters include the focal length f of the telephoto camera about the X-axis, which is to be solved in the camera intrinsic parameter matrix. x The target value, the focal length f of the telephoto camera on the Y-axis to be solved. y The target value, the target value of the distortion parameter k1 to be solved in the second position information, and the transformation matrix to be solved. The target value, and It can be determined by Euler angles (target mounting angles). Therefore, the transformation matrix to be solved is... The target values ​​include the target installation angle, where θ γ These are the angular offsets in the three dimensions of pitch, roll, and yaw.

[0094] Alternatively, before using the LM algorithm, the derivative of each error term with respect to the state variables can be derived for linearization:

[0095] According to formula (2), we have:

[0096]

[0097] Where I is the identity matrix; δ φ φ represents an infinitesimally small change; × is the antisymmetric symbol, which can transform a three-dimensional vector into an antisymmetric matrix.

[0098] According to formula (5), we have:

[0099]

[0100]

[0101] According to formula (5), we have:

[0102]

[0103] According to the chain rule:

[0104]

[0105]

[0106]

[0107]

[0108] Compared to existing technologies, the total station telephoto camera intrinsic parameter and installation angle calibration method of this invention simplifies the camera's intrinsic parameter model by taking advantage of the small distortion characteristic of telephoto lenses. Furthermore, thanks to current manufacturing and installation technologies, it can provide millimeter-level precision lever values ​​for the camera's optical center and the total station's center through structural design values. Based on reprojection errors, the telephoto camera calibration and installation angle calibration are linked, constructing a nonlinear least squares problem model for the telephoto camera's intrinsic parameters and installation angle state variables. In this embodiment of the nonlinear least squares problem, the unknowns are reduced to the telephoto camera's dual-axis focal length, distortion parameters, and installation angle. The theoretical model is complete, the calibration accuracy is high, and the correlation between the telephoto camera's intrinsic parameters and installation angle is weak. Therefore, this invention only requires rotating shots at a single measurement station to calibrate high-precision, highly consistent camera intrinsic parameters and installation angle, greatly improving calibration efficiency. Furthermore, merging the two calibration processes into one simplifies the calibration process and eliminates the need for outdoor calibration. Calibration sites can be set up indoors, reducing the impact of ambient light. Compared to the two-step calibration method, this is more suitable for mass calibration of total station long-range cameras' internal and external parameters on production lines. The calibration site only requires a checkerboard calibration board, further reducing costs.

[0109] This invention also provides a device for calibrating the intrinsic parameters and mounting angle of a total station's telephoto camera, comprising:

[0110] The extraction module is used to capture observation images of the calibration board using a telephoto camera and extract the first position information of the target point in the image coordinate system from the observation images;

[0111] The determination module is used to obtain the relevant position information of the total station and the telephoto camera. Based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera, the second position information is determined. The second position information is obtained by projecting the position information of the target point in the camera coordinate system of the telephoto camera onto the image coordinate system.

[0112] The processing module is used to determine the reprojection error based on the difference between the first position information and the second position information, perform optimization processing based on the reprojection error, and determine the target parameters of the telephoto camera; the target parameters include the target intrinsic parameters and the target mounting angle.

[0113] The content of the above method embodiments is applicable to the device embodiments. The specific functions implemented by the device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments, so they will not be repeated here.

[0114] This invention also provides another device for calibrating the intrinsic parameters and installation angle of a total station's telephoto camera. This device includes a processor and a memory. The memory stores at least one instruction, at least one program, code set, or instruction set. The processor loads and executes the at least one instruction, at least one program, code set, or instruction set to implement the total station telephoto camera intrinsic parameter and installation angle calibration method described in the foregoing embodiments.

[0115] The content of the above method embodiments is applicable to the device embodiments. The specific functions implemented by the device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments, so they will not be repeated here.

[0116] This invention also provides a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set. The at least one instruction, at least one program, code set, or instruction set is loaded and executed by a processor to implement the total station telephoto camera intrinsic parameter and installation angle calibration method of the aforementioned embodiments.

[0117] This invention also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the total station telephoto camera intrinsic parameter and installation angle calibration method described in the foregoing embodiments.

[0118] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0119] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0120] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs. Additionally, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units.

[0121] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0122] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for calibrating the intrinsic parameters and installation angle of a total station's long-focal-length camera, characterized in that... include: The observation image of the calibration board is captured by a telephoto camera, and the first position information of the target point in the image coordinate system is extracted from the observation image. Obtain the relevant position information of the total station and the telephoto camera. This relevant position information includes a first transformation matrix from the total station's carrier coordinate system to the navigation coordinate system, the first coordinates of the total station's center in the navigation coordinate system, the lever arm value between the telephoto camera and the total station's center in the carrier coordinate system, and the second coordinates of the target point in the navigation coordinate system. Based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera, determine the second position information. The second position information is obtained by projecting the target point's position information in the telephoto camera's camera coordinate system onto the image coordinate system. Specifically, based on the first coordinates and the first transformation matrix... The lever arm value, the transformation matrix to be solved, and the second coordinates are used to calculate a first position representation; the transformation matrix to be solved is the transformation matrix from the camera coordinate system to the carrier coordinate system, and the first position representation is the vector from the telephoto camera to the target point in the camera coordinate system; based on the first position representation and a preset distortion formula, a second position representation is calculated; the second position representation is the vector from the telephoto camera to the target point in the camera coordinate system after considering distortion; based on the second position representation and the camera intrinsic parameter matrix, second position information is obtained; the first position representation and the second position representation are specifically as follows: in, Let T be the first position, and T be the transpose. Let be the transformation matrix to be solved. This is the first transformation matrix. The second coordinate, Let be the third coordinate of the telephoto camera's optical center in the navigation coordinate system. This indicates the second position. Let the distortion parameter to be solved be denoted as . X, Y, and Z are components of different coordinate axes; The reprojection error is determined based on the difference between the first position information and the second position information. Optimization processing is then performed based on the reprojection error to determine the target parameters of the telephoto camera. This includes: constructing a least-squares optimization problem model based on the reprojection error; solving the least-squares optimization problem model using the LM algorithm to obtain the target parameters of the telephoto camera; the target intrinsic parameters include the target values ​​of the telephoto camera's focal length about the X-axis and the Y-axis in the camera intrinsic parameter matrix, the target values ​​of the distortion parameters in the second position information, and the target values ​​of the transformation matrix; the target value of the transformation matrix includes the target mounting angle; and the target parameters include the target intrinsic parameters and the target mounting angle.

2. The method for calibrating the intrinsic parameters and installation angle of a total station telephoto camera according to claim 1, characterized in that: The step of extracting the first position information of the target point in the image coordinate system from the observed image includes: Select the corner points of the calibration board from the observed images as target points; Obtain the first position information of the target point in the image coordinate system.

3. The method for calibrating the intrinsic parameters and installation angle of a total station telephoto camera according to claim 1, characterized in that: The step of calculating the first position representation based on the first coordinates, the first transformation matrix, the lever arm value, the transformation matrix to be solved, and the second coordinates includes: Calculate the product of the first transformation matrix and the lever value, and obtain the third coordinate of the telephoto camera's optical center in the navigation coordinate system based on the sum of the product and the first coordinate. Calculate the difference between the second coordinate and the third coordinate, and calculate the first position representation based on the difference, the transformation matrix to be solved, and the first transformation matrix.

4. The method for calibrating the intrinsic parameters and installation angle of a total station telephoto camera according to claim 1, characterized in that: The step of obtaining the second position information based on the second position representation and the camera intrinsic parameter matrix includes: Based on the camera intrinsic parameter matrix, the second position representation is projected onto the image coordinate system to obtain the second position information; the second position information is specifically as follows: The second position indicates T is the transpose. Let be the focal length of the telephoto camera on the X-axis, which needs to be determined. Let be the focal length of the telephoto camera on the Y-axis, which needs to be determined. and These are the X-axis and Y-axis coordinates of the principal point of the telephoto camera, respectively. These are the components of different coordinate axes after considering distortion.

5. A device for calibrating the intrinsic parameters and mounting angle of a total station's telephoto camera, characterized in that, include: The extraction module is used to capture observation images of the calibration board using a telephoto camera and extract the first position information of the target point in the image coordinate system from the observation images; The determination module is used to acquire the relevant position information of the total station and the telephoto camera. This relevant position information includes a first transformation matrix from the total station's carrier coordinate system to the navigation coordinate system, the first coordinate of the total station's center in the navigation coordinate system, the lever arm value between the telephoto camera and the total station's center in the carrier coordinate system, and the second coordinate of the target point in the navigation coordinate system. Based on the relevant position information and the camera intrinsic parameter matrix of the telephoto camera, the second position information is determined. The second position information is obtained by projecting the position information of the target point in the telephoto camera's camera coordinate system onto the image coordinate system. Specifically, based on the first coordinate, the first transformation matrix, and the first transformation matrix, the second position information is determined. The transformation matrix, the lever arm value, the transformation matrix to be solved, and the second coordinates are used to calculate the first position representation; the transformation matrix to be solved is the transformation matrix from the camera coordinate system to the carrier coordinate system, and the first position representation is the representation of the vector from the telephoto camera to the target point in the camera coordinate system; based on the first position representation and a preset distortion formula, the second position representation is calculated; the second position representation is the representation of the vector from the telephoto camera to the target point in the camera coordinate system after considering distortion; based on the second position representation and the camera intrinsic parameter matrix, the second position information is obtained; the first position representation and the second position representation are specifically as follows: in, Let T be the first position, and T be the transpose. Let be the transformation matrix to be solved. This is the first transformation matrix. The second coordinate, Let be the third coordinate of the telephoto camera's optical center in the navigation coordinate system. This indicates the second position. Let the distortion parameter to be solved be denoted as . X, Y, and Z are components of different coordinate axes; The processing module is used to determine the reprojection error based on the difference between the first position information and the second position information, perform optimization processing based on the reprojection error, and determine the target parameters of the telephoto camera, including: constructing a least squares optimization problem model based on the reprojection error; solving the least squares optimization problem model using the LM algorithm to obtain the target parameters of the telephoto camera; the target intrinsic parameters include the target values ​​of the focal length of the telephoto camera to the X-axis and the target values ​​of the focal length of the telephoto camera to the Y-axis in the camera intrinsic parameter matrix, the target values ​​of the distortion parameters to be solved in the second position information, and the target values ​​of the transformation matrix to be solved; the target values ​​of the transformation matrix to be solved include the target installation angle; the target parameters include the target intrinsic parameters and the target installation angle.

6. A device for calibrating the intrinsic parameters and mounting angle of a total station's telephoto camera, characterized in that: The total station telephoto camera internal parameters and installation angle calibration device includes a processor and a memory. The memory stores at least one instruction, at least one program, code set, or instruction set. The at least one instruction, the at least one program, the code set, or instruction set is loaded and executed by the processor to implement the method as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the method as described in any one of claims 1-4.

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