Positioning method and device, computer equipment and storage medium

Abstract

The invention relates to a positioning method and device, computer equipment and a storage medium. The method comprises the following steps: determining feature point global coordinates of region surface feature points of a monocular photography region in a global coordinate system, and fitting a ground curved surface elevation model according to the feature point global coordinates; obtaining a calibration plate image collected by the monocular camera, and determining feature point image point coordinates of the region surface feature points in the image space coordinate system based on the calibration plate image; resection is carried out on the image point coordinates of the feature points and the global coordinates of the feature points, and exterior orientation elements are determined; determining a height distance between the monocular camera and the ground, and determining a target point estimated coordinate of the to-be-positioned target point in a global coordinate system by using a central projection conformation equation according to the exterior orientation elements and the height distance between the monocular camera and the ground; and determining a three-dimensional global coordinate of the target point to be positioned according to the ground surface elevation model and the estimated coordinate of the target point. According to the scheme, the positioning accuracy of the to-be-positioned target point is improved.

Description

Technical Field

[0001] The present application relates to the field of positioning and navigation technology, and in particular to a positioning method, apparatus, computer equipment, and storage medium. Background Art

[0002] Currently, the most commonly used technology for locating targets is satellite positioning, whose pseudorange accuracy typically reaches the meter level. RTK (Reak-time Kinematics) within satellite positioning can achieve centimeter-level accuracy. However, satellite positioning is susceptible to signal interference, making it nearly impossible to use in canyons or indoor environments. To quickly locate targets in environments where satellite signals are obstructed, Wi-Fi positioning and UWB (Ultra-Wideband) are widely used in positioning technology. Wi-Fi positioning uses RSSI (Received Signal Strength Indicator) or fingerprint matching to determine location, making it suitable for indoor scenarios with minimal variability. UWB uses triangulation between at least three base stations to determine the target's position, offering high accuracy and being commonly used in high-precision environments such as factories and hospitals. However, this method is costly and susceptible to multipath interference. Therefore, achieving high-precision and low-cost positioning while avoiding signal interference during the positioning process remains a challenge. Summary of the Invention

[0003] Based on this, it is necessary to provide a positioning method, device, computer equipment and storage medium that can achieve high-precision and low-cost positioning of the target and avoid signal interference during the positioning process to address the above technical problems.

[0004] In a first aspect, the present application provides a positioning method, the method comprising:

[0005] Determining the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and fitting a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located;

[0006] Based on the calibration plate, the image coordinates of the feature points of the regional surface in the regional image of the monocular photography area are determined in the image coordinate system;

[0007] Performing a back intersection on the image point coordinates of the feature points and the global coordinates of the feature points to determine the exterior orientation elements;

[0008] Determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0009] The three-dimensional global coordinates of the target point to be located are determined according to the ground surface elevation model and the estimated coordinates of the target point.

[0010] In one embodiment, determining the coordinates of feature points of regional surface feature points in the regional image of the monocular photography region in the image space coordinate system based on the calibration plate includes:

[0011] Based on the calibration plate, the distortion parameters of the regional image of the monocular photography area are estimated to determine the radial distortion coefficient and the tangential distortion coefficient;

[0012] Based on the radial distortion coefficient and the tangential distortion coefficient, the feature point position of the regional surface feature point in the regional image is subjected to distortion correction, and the corrected feature point position is subjected to image principal point correction by an image principal point correction device to determine the feature point image point coordinates.

[0013] In one embodiment, fitting a ground surface elevation model according to the global coordinates of the feature points includes:

[0014] Performing decentering processing on the global coordinates of the feature points to determine decentering coordinates;

[0015] determining a polynomial surface model according to the decentering coordinates;

[0016] The polynomial surface model is solved by the least square method to determine the ground surface elevation model.

[0017] In one embodiment, performing a back intersection on the image point coordinates of the feature point and the global coordinates of the feature point to determine the exterior orientation elements includes:

[0018] Determining the initial value of the exterior orientation element according to the coordinate mean of the global coordinates of the feature point;

[0019] Constructing an error equation based on the image control points of the sample image captured by the monocular camera, and determining the element correction number of the exterior orientation element based on the error equation and the initial value;

[0020] According to the element correction number, the feature point image point coordinates and the initial value, the exterior orientation elements after the feature point image point coordinates and the feature point global coordinates are resected are determined.

[0021] In one embodiment, constructing an error equation based on image control points of a sample image captured by a monocular camera includes:

[0022] Determine the image control points of the sample image captured by the monocular camera, and determine the global coordinates of the control points of the image control points in the global coordinate system;

[0023] Determining the image coordinates of the control point of the image control point in the image coordinate system, and determining the estimated coordinates of the control point of the image control point based on the image coordinates of the control point, the image coordinates of the feature point, and the height distance between the monocular camera and the ground;

[0024] An error equation is constructed according to the estimated coordinates of the control points and the global coordinates of the control points.

[0025] In one embodiment, determining the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point includes:

[0026] Substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located;

[0027] Determining an elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the estimated coordinates of the target point;

[0028] If the elevation coordinate difference is less than or equal to a coordinate difference threshold, the estimated elevation coordinate is determined to be the three-dimensional global coordinate of the target point to be located.

[0029] In one embodiment, after determining the elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the estimated coordinate of the target point, the method further includes:

[0030] If the elevation coordinate difference is greater than a coordinate difference threshold, updating the estimated elevation coordinates in the estimated coordinates of the target point based on the updated elevation coordinates;

[0031] Based on the updated estimated coordinates of the target point, the process returns to execute substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

[0032] In a second aspect, the present application further provides a positioning device, comprising:

[0033] A ground elevation model determination module is used to determine the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and to fit a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located;

[0034] An image point coordinate determination module is used to determine the image point coordinates of feature points of the regional surface in the regional image of the monocular photography area in the image coordinate system based on the calibration plate;

[0035] An exterior orientation element determination module, configured to perform a rear intersection on the image coordinates of the feature points and the global coordinates of the feature points to determine exterior orientation elements;

[0036] An estimated coordinate determination module is used to determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0037] The three-dimensional global coordinate determination module is used to determine the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point.

[0038] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0039] Determining the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and fitting a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located;

[0040] Based on the calibration plate, the image coordinates of the feature points of the regional surface in the regional image of the monocular photography area are determined in the image coordinate system;

[0041] Performing a back intersection on the image point coordinates of the feature points and the global coordinates of the feature points to determine the exterior orientation elements;

[0042] Determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0043] The three-dimensional global coordinates of the target point to be located are determined according to the ground surface elevation model and the estimated coordinates of the target point.

[0044] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the following steps:

[0045] Determining the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and fitting a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located;

[0046] Based on the calibration plate, the image coordinates of the feature points of the regional surface in the regional image of the monocular photography area are determined in the image coordinate system;

[0047] Performing a back intersection on the image point coordinates of the feature points and the global coordinates of the feature points to determine the exterior orientation elements;

[0048] Determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0049] The three-dimensional global coordinates of the target point to be located are determined according to the ground surface elevation model and the estimated coordinates of the target point.

[0050] The positioning method, device, computer equipment and storage medium described above determine the global coordinates of the feature points of the regional surface of the monocular photography area in the global coordinate system, and fit the ground surface elevation model based on the global coordinates of the feature points; obtain the calibration plate image captured by the monocular camera, and based on the calibration plate image, determine the image coordinates of the feature points of the regional surface in the image coordinate system; perform a back intersection between the image coordinates of the feature points and the global coordinates of the feature points to determine the exterior orientation elements; determine the height distance between the monocular camera and the ground, and use the central projection conformation equation to determine the estimated coordinates of the target point to be located in the global coordinate system based on the exterior orientation elements and the height distance between the monocular camera and the ground; determine the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point. This method solves the problem of low positioning accuracy caused by signal interference when directly positioning the target using satellite positioning technology, and also solves the problem of high cost and susceptibility to signal interference when determining the position of the target using triangulation through multiple base stations. The above scheme determines the global coordinates of the feature points of the regional surface feature points in the global coordinate system based on the calibration plate image captured by the monocular camera, and determines the image point coordinates of the feature points of the regional surface feature points in the image coordinate system, fits the ground surface elevation model according to the global coordinates of the feature points, determines the exterior orientation elements according to the image point coordinates of the feature points and the global coordinates of the feature points, and determines the three-dimensional global coordinates of the target point to be located according to the height distance between the monocular camera and the ground of the exterior orientation element through the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point to be located, avoiding signal interference, and reducing the positioning cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A diagram of an application environment of a positioning method in one embodiment;

[0052] Figure 2 1 is a flow chart of a positioning method according to an embodiment;

[0053] Figure 3 1 is a flow chart of a method for determining a ground surface elevation model in one embodiment;

[0054] Figure 4 is a flowchart of a positioning method in another embodiment;

[0055] Figure 5 This is an example diagram of the distribution of regional surface feature points in one embodiment;

[0056] Figure 6 This is an example diagram of the distribution of regional surface feature points in another embodiment;

[0057] Figure 7 is a structural block diagram of a positioning device in one embodiment;

[0058] Figure 8 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0060] The positioning method provided in the embodiment of the present application can be applied to Figure 1The application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data required by the server 104 to process. The data storage system can be integrated on the server 104, or placed on the cloud or other network servers. The server 104 determines the feature point global coordinates of the regional surface feature points of the monocular photography region in the global coordinate system, and fits the ground surface elevation model according to the feature point global coordinates; The monocular photography region contains a target point to be positioned; Based on the calibration board, the feature point image coordinates of the regional surface feature points in the regional image of the monocular photography region are determined in the image coordinate system; The feature point image coordinates and the feature point global coordinates are rear intersection, to determine the exterior orientation element; Determine the height distance between the monocular camera and the ground, use the central projection conformation equation, according to the exterior orientation element and the height distance between the monocular camera and the ground, determine the target point pre-estimation coordinates of the target point to be positioned in the global coordinate system; According to the ground surface elevation model and the target point pre-estimation coordinates, determine the three-dimensional global coordinates of the target point to be positioned, and send the three-dimensional global coordinates of the target point to be positioned to the terminal 102 through the communication network. Among them, the terminal 102 can be, but not limited to, various personal computers, notebook computers, smart phones, tablet computers, Internet of Things devices and portable wearable devices, Internet of Things devices can be smart speakers, smart televisions, smart air conditioners, smart car devices, etc. Portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be realized by an independent server or a server cluster composed of multiple servers.

[0061] In one embodiment, as Figure 2 shown, a positioning method is provided, and the embodiment is exemplified by applying the method to a terminal. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is realized through the interaction of the terminal and the server. In the embodiment, the method includes the following steps:

[0062] S210, determine the feature point global coordinates of the regional surface feature points of the monocular photography region in the global coordinate system, and fit the ground surface elevation model according to the feature point global coordinates.

[0063] The monocular photography region contains a target point to be positioned.

[0064] Among them, the monocular photography area refers to the shooting area of ​​the monocular camera. In photography, regional surface feature points usually refer to areas with obvious visual features in the picture. These areas form visual focal points through elements such as shape, texture, and light and dark contrast, which can guide the viewer's sight and enhance the expressiveness of the picture. The global coordinate system refers to the coordinate system based on which the RTK positioning method is used for positioning, that is, the satellite positioning coordinate system. The coordinates of objects determined in the global coordinate system are generally longitude and latitude coordinates. The target point to be located refers to the feature point corresponding to the target object that needs to be located. The ground surface elevation model refers to a mathematical model that can describe the elevation of the ground surface. The ground surface elevation refers to the elevation of objects on the ground.

[0065] Specifically, RTK technology is used to determine the global coordinates of the feature points of the regional surface of the monocular photography area in the global coordinate system, and the ground surface elevation model is fitted according to the global coordinates of the feature points. Preferably, the number of the regional surface feature points of the monocular photography area is greater than or equal to 6.

[0066] For example, Figure 3 As shown, the ground surface elevation model is fitted according to the global coordinates of the feature points, including:

[0067] The global coordinates of the feature points are decentered to determine the decentered coordinates; a polynomial surface model is determined based on the decentered coordinates; the polynomial surface model is solved by the least squares method to determine the ground surface elevation model.

[0068] It should be noted that the global coordinates of the feature points are evenly distributed within the monocular photography area. Decentering image feature points typically involves calculating the centroid coordinates of the feature points and performing coordinate transformation or normalization based on them during image processing to eliminate coordinate offsets caused by operations such as image rotation and scaling.

[0069] Specifically, the global coordinates of the feature points are decentered to determine the decentered coordinates, and the polynomial surface model is determined based on the decentered coordinates. For example, the formula of the polynomial surface model is shown in formula (1):

[0070] (1)

[0071] Where (X, Y, Z) refers to the decentralized coordinates, and a0, a1, a2, a3, a4, and a5 are the coefficients to be solved. When there are 6 coefficients to be solved, the number of regional surface feature points in the monocular photography area is at least 6. Substituting the decentralized coordinates of the regional surface feature points into formula (1) and solving formula (1) using the least squares method, we can obtain the values ​​of a0, a1, a2, a3, a4, and a5. Substituting the obtained values ​​of the coefficients to be solved into formula (1) again, we can determine the ground surface elevation model.

[0072] The above scheme provides a method for constructing a ground surface elevation model. The polynomial surface model is determined based on the decentered coordinates, and the ground surface elevation model is determined based on the solution of the polynomial surface model. This can construct a simple and effective ground surface elevation model.

[0073] S220 , determining the image point coordinates of the feature points of the regional surface in the regional image of the monocular photography region in the image space coordinate system based on the calibration plate.

[0074] The monocular photography area contains the target point to be located.

[0075] A monocular camera is a visual sensor that continuously outputs images using a single optical system and solid-state imaging device, achieving environmental perception based on the principle of monocular imaging. A monocular camera can be mounted on a vehicle. Its core function is to capture a 2D image through a monocular lens and, combined with computer vision algorithms, estimate 3D information such as the target object's distance and velocity. A calibration plate is a device used in machine vision, image measurement, photogrammetry, and 3D reconstruction. Using a flat plate with a fixed-pitch pattern array, it helps correct lens distortion, determine the conversion relationship between physical dimensions and pixels, and establish a geometric model for camera imaging. A calibration plate image, captured by a monocular camera, is primarily used to correct lens distortion, determine the conversion relationship between physical dimensions and pixels, and establish the relationship between surface points of a spatial object and their corresponding points in the image. By capturing an image of the plate with the fixed-pitch pattern array and applying a calibration algorithm to this image, the camera's geometric model can be derived, resulting in high-precision measurement and reconstruction results. The plate with the fixed-pitch pattern array is the calibration plate. The monocular imaging area refers to the area captured by the monocular camera. In photography, regional surface feature points usually refer to areas with obvious visual features in the picture. These areas form visual focal points through elements such as shape, texture, and light and dark contrast, which can guide the viewer's line of sight and enhance the expressiveness of the picture. The global coordinate system refers to the coordinate system based on which RTK positioning is performed, that is, the satellite positioning coordinate system. The coordinates of an object determined in the global coordinate system are generally longitude and latitude coordinates. The target point to be located refers to the feature point corresponding to the target object that needs to be located. The image space coordinate system is the core coordinate system used in photogrammetry to describe the spatial position of image points on a single photograph. It achieves precise coordinate expression through the right-handed rectangular coordinate system specification. Image point coordinates refer to the position coordinates of a pixel point on the image, and feature point image point coordinates refer to the position coordinates of the pixel point corresponding to the feature point, that is, the coordinates of the feature point in the image space coordinate system.

[0076] Specifically, a regional image of a monocular photography area captured by a monocular camera is obtained, and the coordinates of the regional surface feature points in the image coordinate system are calibrated based on a calibration plate to determine the feature point image coordinates of the regional surface feature points in the image coordinate system.

[0077] Exemplarily, a method for determining the coordinates of a feature point image point includes:

[0078] Based on the calibration plate, the distortion parameters of the regional image of the monocular photography area are estimated to determine the radial distortion coefficient and the tangential distortion coefficient; based on the radial distortion coefficient and the tangential distortion coefficient, the feature point positions of the regional surface feature points in the regional image are subjected to distortion correction, and the principal point correction of the corrected feature point positions is performed through the principal point correction device to determine the image point coordinates of the feature points.

[0079] It's important to note that distortion correction is a technique that extracts feature points from an image and maps them to real-world coordinates to correct image distortion. Common methods include model-based correction, feature point matching, and grid correction. Radial distortion is caused by imperfect lens shape and manifests as stretched or squeezed image edges. Tangential distortion is caused by the lens not being parallel to the imaging plane, resulting in tilted image lines.

[0080] Specifically, the determination of radial distortion and tangential distortion is mainly achieved through Zhang's calibration method. Zhang's calibration method obtains the correspondence between image coordinates and world coordinates based on a specific pattern on the calibration plate, and then calculates the distortion parameters. Based on the radial distortion coefficient and the tangential distortion coefficient, the position of the regional surface feature point in the regional image is corrected for distortion, and the principal point correction is performed on the corrected feature point position through the principal point correction device to determine the feature point image point coordinates. Among them, the principal point correction refers to adjusting the principal point position to eliminate its deviation from the theoretical position, thereby improving the geometric accuracy of the image. The principal point correction methods mainly include principal point offset and distortion correction. Principal point offset is to accurately measure the deviation between the actual principal point and the theoretical position through camera calibration, and correct it in aerial triangulation. Distortion correction includes radial distortion, tangential distortion, film deformation, etc., which are eliminated through mathematical models or equipment calibration.

[0081] It should be noted that the Zhang calibration method uses a planar checkerboard pattern to perform linear solution and nonlinear optimization of camera parameters to establish an imaging geometry model and correct lens distortion. Exemplary methods for determining distortion parameters may include: identifying corner coordinates on a calibration plate image using an image recognition algorithm, generating a homogeneous matrix based on the corner coordinates, and calculating the distortion parameters using intrinsic and extrinsic parameters.

[0082] For example, the formulas for correcting regional surface feature points based on the radial distortion coefficient are shown in formulas (2) and (3):

[0083] X corrected1 =X distorted ×(1+k1r 2 +k2r 4 +k3r 6)(2)

[0084] Y corrected1 =Y distorted ×(1+k1r 2 +k2r 4 +k3r 6 )(3)

[0085] Among them, (X distorted , Y distorted ) is the position of the feature point of the regional surface in the calibration plate image; (X corrected1 , Y corrected1 ) is the position of the regional surface feature point after correction based on the radial distortion coefficient; k1, k2 and k3 are the radial distortion coefficients; r is the distance between the regional surface feature point and the center of the calibration plate image.

[0086] Then, based on the tangential distortion coefficient, the position of the regional surface feature point after correction based on the radial distortion coefficient is corrected to determine the corrected feature point position. The formula for determining the corrected feature point position is shown in formula (4) and formula (5):

[0087] X corrected2 =X corrected1 +2p1×X corrected1 Y corrected1 +p2(r 2 +2X 2 corrected1 )(4)

[0088] Y corrected2 =Y corrected1 +p1(r 2 +2Y 2 corrected1 )+2p2×X corrected1 Y corrected1 (5)

[0089] Among them, (X corrected2 , Y corrected2 ) is the corrected feature point position; p1 and p2 are the tangential distortion coefficients.

[0090] S230 , performing a back intersection on the feature point image point coordinates and the feature point global coordinates to determine the exterior orientation elements.

[0091] Resection is a surveying method that involves setting up a station at the point to be determined and observing a horizontal angle A between two known control points to calculate the coordinates of the point to be determined. This can be achieved using a total station or theodolite. Exterior orientation elements are the six parameters determined in photogrammetry: the spatial position of the photographic center (Xs, Ys, Zs) and the image attitude angles (φ, ω, κ). They are used to establish the spatial geometric relationship between the image and the real object.

[0092] Exemplarily, the exterior orientation elements are determined as follows:

[0093] The initial value of the exterior orientation element is determined according to the coordinate mean of the global coordinate of the feature point; the error equation is constructed according to the image control point of the sample image captured by the monocular camera, and the element correction number of the exterior orientation element is determined according to the error equation and the initial value; the exterior orientation element after the feature point image point coordinate and the global coordinate of the feature point are rear-intersected is determined according to the element correction number, the feature point image point coordinate and the initial value.

[0094] Corrections generally refer to adjustments made to original observations to eliminate observation errors. Their core function is to improve measurement accuracy by correcting observations to theoretical values ​​using mathematical models or algorithms. Photographic control points are used for photogrammetry to encrypt control points or to establish and measure control points in the field for mapping. Sample images can be historical images captured by a monocular camera. Photographic control points can be set based on the actual needs of the scene.

[0095] Specifically, the mean value of the feature point's global coordinates is used as the initial value of the exterior orientation element. Specifically, the mean value of the feature point's global coordinates is used as the initial value of the exterior orientation element's horizontal coordinate, and the mean value of the feature point's global coordinates is used as the initial value of the exterior orientation element's vertical coordinate. An error equation is constructed based on the image control points of a sample image captured by a monocular camera. The initial values ​​of the exterior orientation elements are input into the error equation, and element corrections for the exterior orientation elements are calculated based on the error equation. Based on the element corrections, the feature point image coordinates, and the initial values, the exterior orientation elements are determined after resection of the feature point image coordinates with the feature point's global coordinates.

[0096] For example, the calculation formula of the exterior orientation element is shown in formula (6):

[0097] (6)

[0098] Among them, (x, y) is the coordinate of the feature point image; (x0, y0) is the initial value of the exterior orientation element; is the element correction number of the exterior orientation element; It is the exterior orientation element that needs to be determined.

[0099] The above scheme proposes a method for calculating exterior orientation elements. According to the element correction number, the feature point image point coordinates and the initial value, the exterior orientation elements after the feature point image point coordinates and the feature point global coordinates are resected are determined, which can improve the accuracy of the exterior orientation elements.

[0100] Exemplarily, the error equation is constructed based on the image control points of the sample image captured by the monocular camera, including:

[0101] The method comprises the following steps: determining an image control point of a sample image captured by a monocular camera, and determining the global coordinates of the control point of the image control point in a global coordinate system; determining the image point coordinates of the control point of the image control point in an image space coordinate system, and determining the estimated control point coordinates of the image control point based on the image point coordinates of the control point, the image point coordinates of the feature point, and the height distance between the monocular camera and the ground; and constructing an error equation based on the estimated control point coordinates and the global coordinates of the control point.

[0102] The above solution provides a method for constructing an error equation, and solving the element correction number of the exterior orientation element according to the constructed error equation. Solving the exterior orientation element based on the element correction number can improve the reliability of the exterior orientation element.

[0103] S240, determining the height distance between the monocular camera and the ground, and using the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground.

[0104] The height distance between the monocular camera and the ground is the approximate height distance between the monocular camera and the ground.

[0105] Specifically, determine the approximate height distance h between the monocular camera and the ground, determine the difference between Zs in the exterior orientation element and the approximate height distance h, and use the inverse of the central projection conformation equation and the difference between the vertical coordinates in the exterior orientation element and the height distance to determine the estimated coordinates of the target point to be located in the global coordinate system.

[0106] For example, the estimated coordinates (Xp, Yp, Zp) of the target point to be located in the global coordinate system can be determined according to formula (7) and formula (8):

[0107] (7)

[0108] Z P =Z S -h(8)

[0109] Among them, (x, y) is the coordinate of the feature point image; r is the element of the orthogonal matrix generated by the three external azimuth elements of the camera; f is the coefficient.

[0110] S250: Determine the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point.

[0111] Exemplarily, a method for determining the three-dimensional global coordinates of a target point to be located includes:

[0112] Substitute the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located; determine the elevation coordinate difference between the updated elevation coordinates and the estimated elevation coordinates in the estimated coordinates of the target point; if the elevation coordinate difference is less than or equal to the coordinate difference threshold, determine the estimated elevation coordinates as the three-dimensional global coordinates of the target point to be located.

[0113] Specifically, according to formula (7) and formula (8), the approximate plane coordinates (X p ,Y p ), the approximate plane coordinates (X p ,Y p ) is substituted into the ground surface elevation model to obtain the updated elevation coordinates of the target point to be located The elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the target point estimated coordinate is determined, and if the elevation coordinate difference is less than or equal to the coordinate difference threshold, the estimated elevation coordinate is determined to be the three-dimensional global coordinate of the target point to be located.

[0114] The above scheme determines the updated elevation coordinates of the target point to be located based on the ground surface elevation model, and determines the three-dimensional global coordinates of the target point to be located based on the updated elevation coordinates and the estimated elevation coordinates in the target point estimated coordinates. This can reduce the cost of locating the target point to be located while ensuring positioning accuracy.

[0115] Exemplarily, if the elevation coordinate difference is greater than the coordinate difference threshold, the estimated elevation coordinates in the target point estimated coordinates are updated based on the updated elevation coordinates; based on the updated target point estimated coordinates, the estimated coordinates of the target point are substituted into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

[0116] In the above scheme, when the elevation coordinate difference is greater than the coordinate difference threshold, the estimated coordinates of the target point are iteratively updated, and the updated elevation coordinates of the target point to be located are recalculated based on the updated estimated coordinates of the target point, until the elevation coordinate difference between the updated elevation coordinates and the estimated elevation coordinates in the target point estimated coordinates is less than or equal to the coordinate difference threshold, thereby achieving accurate positioning of the target point to be located.

[0117] In the above positioning method, the global coordinates of the regional surface feature points of the monocular photography area in the global coordinate system are determined, and the ground surface elevation model is fitted based on the global coordinates of the feature points; the calibration plate image captured by the monocular camera is obtained, and based on the calibration plate image, the image coordinates of the feature points of the regional surface feature points in the image coordinate system are determined; the image coordinates of the feature points and the global coordinates of the feature points are intersected to determine the exterior orientation elements; the height distance between the monocular camera and the ground is determined, and the central projection conformation equation is used to determine the estimated coordinates of the target point to be located in the global coordinate system based on the exterior orientation elements and the height distance between the monocular camera and the ground; the three-dimensional global coordinates of the target point to be located are determined based on the ground surface elevation model and the estimated coordinates of the target point. This method solves the problem of low positioning accuracy caused by signal interference when directly positioning the target using satellite positioning technology, and also solves the problem of high cost and easy signal interference when determining the position of the target using triangulation through multiple base stations. The above scheme determines the global coordinates of the feature points of the regional surface feature points in the global coordinate system based on the calibration plate image captured by the monocular camera, and determines the image point coordinates of the feature points of the regional surface feature points in the image coordinate system, fits the ground surface elevation model according to the global coordinates of the feature points, determines the exterior orientation elements according to the image point coordinates of the feature points and the global coordinates of the feature points, and determines the three-dimensional global coordinates of the target point to be located according to the height distance between the monocular camera and the ground of the exterior orientation element through the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point to be located, avoiding signal interference, and reducing the positioning cost.

[0118] For example, Figure 4 As shown, based on the above embodiment, the positioning method includes:

[0119] The global coordinates of the feature points are decentered to determine the decentered coordinates. A polynomial surface model is determined based on the decentered coordinates. The polynomial surface model is solved using the least squares method to determine the ground surface elevation model. The radial and tangential distortion coefficients are determined based on the calibration plate image. Based on these coefficients, the positions of the regional surface feature points in the calibration plate image are corrected for distortion. The principal point correction is then applied to the corrected feature point positions using an image principal point correction device to determine the feature point image coordinates.

[0120] The method comprises the following steps: determining an image control point of a sample image captured by a monocular camera, and determining the global coordinates of the control point of the image control point in a global coordinate system; determining the image point coordinates of the control point of the image control point in an image space coordinate system, and determining the estimated control point coordinates of the image control point based on the image point coordinates of the control point, the image point coordinates of the feature point, and the height distance between the monocular camera and the ground; and constructing an error equation based on the estimated control point coordinates and the global coordinates of the control point.

[0121] The mean value of the feature point's global coordinates is used as the initial value of the exterior orientation element. An error equation is constructed based on the control points of the sample image captured by the monocular camera. The initial value of the exterior orientation element is input into the error equation, and the element correction of the exterior orientation element is calculated based on the error equation. Based on the element correction, the feature point image coordinates, and the initial value, the exterior orientation element is determined after resection between the feature point image coordinates and the feature point's global coordinates.

[0122] Determine the height distance between the monocular camera and the ground, determine the difference between the vertical coordinate and the height distance in the exterior orientation element, and use the inverse of the central projection conformation equation and the difference between the vertical coordinate and the height distance in the exterior orientation element to determine the estimated coordinates of the target point to be located in the global coordinate system.

[0123] Substitute the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located. Determine the elevation difference between the updated elevation coordinates and the estimated elevation coordinates in the target point's estimated coordinates. If the elevation difference is less than or equal to the coordinate difference threshold, determine the estimated elevation coordinates as the 3D global coordinates of the target point to be located. If the elevation difference is greater than the coordinate difference threshold, update the estimated elevation coordinates in the target point's estimated coordinates based on the updated elevation coordinates. Based on the updated target point's estimated coordinates, return to execute and substitute the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

[0124] In the above positioning method, the global coordinates of the regional surface feature points of the monocular photography area in the global coordinate system are determined, and the ground surface elevation model is fitted based on the global coordinates of the feature points; the calibration plate image captured by the monocular camera is obtained, and based on the calibration plate image, the image coordinates of the feature points of the regional surface feature points in the image coordinate system are determined; the image coordinates of the feature points and the global coordinates of the feature points are intersected to determine the exterior orientation elements; the height distance between the monocular camera and the ground is determined, and the central projection conformation equation is used to determine the estimated coordinates of the target point to be located in the global coordinate system based on the exterior orientation elements and the height distance between the monocular camera and the ground; the three-dimensional global coordinates of the target point to be located are determined based on the ground surface elevation model and the estimated coordinates of the target point. This method solves the problem of low positioning accuracy caused by signal interference when directly positioning the target using satellite positioning technology, and also solves the problem of high cost and easy signal interference when determining the position of the target using triangulation through multiple base stations. The above scheme determines the global coordinates of the feature points of the regional surface feature points in the global coordinate system based on the calibration plate image captured by the monocular camera, and determines the image point coordinates of the feature points of the regional surface feature points in the image coordinate system, fits the ground surface elevation model according to the global coordinates of the feature points, determines the exterior orientation elements according to the image point coordinates of the feature points and the global coordinates of the feature points, and determines the three-dimensional global coordinates of the target point to be located according to the height distance between the monocular camera and the ground of the exterior orientation element through the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point to be located, avoiding signal interference, and reducing the positioning cost.

[0125] For example, 11 regional surface feature points are collected in the photographic area, 7 of which are used to fit the ground surface elevation model, and the remaining 4 regional surface feature points, i.e., the feature points in the rectangular frame, are used to verify the positioning accuracy. Figure 5 The positioning accuracy is shown in Table 1.

[0126] Table 1

[0127]

[0128] For example, 14 regional surface feature points are collected in the photographic area, of which 9 regional surface feature points are used to fit the ground surface elevation model, and the remaining 5 regional surface feature points, i.e., the feature points in the rectangular frame, are used to verify the positioning accuracy. The distribution of the 14 regional surface feature points is as follows: Figure 6 The positioning accuracy is shown in Table 2.

[0129] Table 2

[0130]

[0131] It should be understood that although the steps in the flowcharts involved in the embodiments described above are shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the embodiments described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0132] Based on the same inventive concept, the embodiments of the present application also provide a positioning device for implementing the positioning method described above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more positioning device embodiments provided below can refer to the limitations of the positioning method described above, and will not be repeated here.

[0133] In one embodiment, as shown in Figure 7 A positioning device is provided, comprising: a ground elevation model determination module 501, a pixel point coordinate determination module 502, an exterior orientation element determination module 503, a predicted coordinate determination module 504, and a three-dimensional global coordinate determination module 505, wherein:

[0134] The ground elevation model determination module 501 is configured to determine the feature point global coordinates of the regional feature points of the monocular photography region in the global coordinate system, and fit a ground surface elevation model according to the feature point global coordinates; the monocular photography region contains a target point to be positioned;

[0135] The pixel point coordinate determination module 502 is configured to determine the feature point pixel point coordinates of the regional feature points in the regional image of the monocular photography region in the image coordinate system based on a calibration board;

[0136] The exterior orientation element determination module 503 is configured to perform resection of the feature point pixel point coordinates and the feature point global coordinates to determine the exterior orientation elements;

[0137] The predicted coordinate determination module 504 is configured to determine the height distance between the monocular camera and the ground, and determine the target point predicted coordinates of the target point to be positioned in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground by using the central projection conformation equation;

[0138] The three-dimensional global coordinate determination module 505 is used to determine the three-dimensional global coordinates of the target point to be located according to the ground surface elevation model and the estimated coordinates of the target point.

[0139] Exemplarily, the image point coordinate determination module 502 is specifically configured to:

[0140] Based on the calibration plate, the distortion parameters of the regional image of the monocular photography area are estimated to determine the radial distortion coefficient and the tangential distortion coefficient;

[0141] Based on the radial distortion coefficient and the tangential distortion coefficient, the feature point position of the regional surface feature point in the regional image is subjected to distortion correction, and the corrected feature point position is subjected to image principal point correction by an image principal point correction device to determine the feature point image point coordinates.

[0142] Furthermore, the ground elevation model determination module 501 is specifically configured to:

[0143] Performing decentering processing on the global coordinates of the feature points to determine decentering coordinates;

[0144] determining a polynomial surface model according to the decentering coordinates;

[0145] The polynomial surface model is solved by the least square method to determine the ground surface elevation model.

[0146] Exemplarily, the exterior element determination module 503 is specifically configured to:

[0147] Determining the initial value of the exterior orientation element according to the coordinate mean of the global coordinates of the feature point;

[0148] Constructing an error equation based on the image control points of the sample image captured by the monocular camera, and determining the element correction number of the exterior orientation element based on the error equation and the initial value;

[0149] According to the element correction number, the feature point image point coordinates and the initial value, the exterior orientation elements after the feature point image point coordinates and the feature point global coordinates are resected are determined.

[0150] Exemplarily, the exterior orientation element determination module 503 is further specifically configured to:

[0151] Determine the image control points of the sample image captured by the monocular camera, and determine the global coordinates of the control points of the image control points in the global coordinate system;

[0152] Determining the image coordinates of the control point of the image control point in the image coordinate system, and determining the estimated coordinates of the control point of the image control point based on the image coordinates of the control point, the image coordinates of the feature point, and the height distance between the monocular camera and the ground;

[0153] An error equation is constructed according to the estimated coordinates of the control points and the global coordinates of the control points.

[0154] Exemplarily, the three-dimensional global coordinate determination module 505 is specifically configured to:

[0155] Substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located;

[0156] Determining an elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the estimated coordinates of the target point;

[0157] If the elevation coordinate difference is less than or equal to a coordinate difference threshold, the estimated elevation coordinate is determined to be the three-dimensional global coordinate of the target point to be located.

[0158] Exemplarily, the three-dimensional global coordinate determination module 505 is further specifically configured to:

[0159] If the elevation coordinate difference is greater than a coordinate difference threshold, updating the estimated elevation coordinates in the estimated coordinates of the target point based on the updated elevation coordinates;

[0160] Based on the updated estimated coordinates of the target point, the process returns to execute substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

[0161] Each module in the positioning device described above can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0162] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8As shown. The computer device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals via wired or wireless means, and the wireless means can be achieved via Wi-Fi, mobile cellular networks, NFC (near-field communication), or other technologies. When executed by the processor, the computer program implements a positioning method. The display unit of the computer device is used to form a visually visible image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0163] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0164] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0165] Step 1: determining the global coordinates of the feature points of the regional surface of the monocular photography area in the global coordinate system, and fitting the ground surface elevation model according to the global coordinates of the feature points; the monocular photography area contains the target point to be located;

[0166] Step 2: Obtain the calibration plate image captured by the monocular camera, and based on the calibration plate image, determine the feature point image coordinates of the regional surface feature points in the image coordinate system;

[0167] Step 3: Perform a back intersection on the feature point image coordinates and the feature point global coordinates to determine the exterior orientation elements;

[0168] Step four, determining the height distance between the monocular camera and the ground, using the central projection configuration equation, determining the target point estimated coordinates of the target point to be positioned in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0169] Step five, determining the three-dimensional global coordinates of the target point to be positioned according to the ground surface elevation model and the target point estimated coordinates.

[0170] In one embodiment, a computer readable storage medium is provided, and a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to implement the following steps:

[0171] Step one, determining the feature point global coordinates of the regional surface feature points in the monoscopic photography region in the global coordinate system, and fitting the ground surface elevation model according to the feature point global coordinates; the monoscopic photography region contains the target point to be positioned;

[0172] Step two, acquiring the calibration board image collected by the monocular camera, and determining the feature point image point coordinates of the regional surface feature points in the image coordinate system based on the calibration board image;

[0173] Step three, performing resection on the feature point image point coordinates and the feature point global coordinates to determine the exterior orientation elements;

[0174] Step four, determining the height distance between the monocular camera and the ground, using the central projection configuration equation, determining the target point estimated coordinates of the target point to be positioned in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground;

[0175] Step five, determining the three-dimensional global coordinates of the target point to be positioned according to the ground surface elevation model and the target point estimated coordinates.

[0176] In one embodiment, a computer program product is provided, and the computer program product includes a computer program, and the computer program is executed by a processor to implement the following steps:

[0177] Step one, determining the feature point global coordinates of the regional surface feature points in the monoscopic photography region in the global coordinate system, and fitting the ground surface elevation model according to the feature point global coordinates; the monoscopic photography region contains the target point to be positioned;

[0178] Step two, acquiring the calibration board image collected by the monocular camera, and determining the feature point image point coordinates of the regional surface feature points in the image coordinate system based on the calibration board image;

[0179] Step three, performing resection on the feature point image point coordinates and the feature point global coordinates to determine the exterior orientation elements;

[0180] Step 4: Determine the height distance between the monocular camera and the ground, and use the central projection conformation equation to determine the estimated coordinates of the target point to be located in the global coordinate system based on the exterior orientation elements and the height distance between the monocular camera and the ground;

[0181] Step 5: Determine the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point.

[0182] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions.

[0183] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0184] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0185] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A positioning method, characterized in that: include: Determining the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and fitting a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located; Based on the calibration plate, the image coordinates of the feature points of the regional surface in the regional image of the monocular photography area are determined in the image coordinate system; Performing a back intersection on the image point coordinates of the feature points and the global coordinates of the feature points to determine the exterior orientation elements; Determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground; The three-dimensional global coordinates of the target point to be located are determined according to the ground surface elevation model and the estimated coordinates of the target point.

2. The method according to claim 1, characterized in that Based on the calibration plate, the coordinates of the feature points of the regional surface in the regional image of the monocular photography area in the image coordinate system are determined, including: Based on the calibration plate, the distortion parameters of the regional image of the monocular photography area are estimated to determine the radial distortion coefficient and the tangential distortion coefficient; Based on the radial distortion coefficient and the tangential distortion coefficient, the feature point position of the regional surface feature point in the regional image is subjected to distortion correction, and the corrected feature point position is subjected to image principal point correction by an image principal point correction device to determine the feature point image point coordinates.

3. The method according to claim 1, characterized in that Fitting a ground surface elevation model according to the global coordinates of the feature points includes: Performing decentering processing on the global coordinates of the feature points to determine decentering coordinates; determining a polynomial surface model according to the decentering coordinates; The polynomial surface model is solved by the least square method to determine the ground surface elevation model.

4. The method according to claim 1, wherein Performing a back intersection on the image point coordinates of the feature point and the global coordinates of the feature point to determine the exterior orientation elements includes: Determining the initial value of the exterior orientation element according to the coordinate mean of the global coordinates of the feature point; Constructing an error equation based on the image control points of the sample image captured by the monocular camera, and determining the element correction number of the exterior orientation element based on the error equation and the initial value; According to the element correction number, the feature point image point coordinates and the initial value, the exterior orientation elements after the feature point image point coordinates and the feature point global coordinates are resected are determined.

5. The method according to claim 4, characterized in that The error equation is constructed based on the image control points of the sample image captured by the monocular camera, including: Determine the image control points of the sample image captured by the monocular camera, and determine the global coordinates of the control points of the image control points in the global coordinate system; Determining the image coordinates of the control point of the image control point in the image coordinate system, and determining the estimated coordinates of the control point of the image control point based on the image coordinates of the control point, the image coordinates of the feature point, and the height distance between the monocular camera and the ground; An error equation is constructed according to the estimated coordinates of the control points and the global coordinates of the control points.

6. The method according to claim 1, characterized in that Determining the three-dimensional global coordinates of the target point to be located according to the ground surface elevation model and the estimated coordinates of the target point includes: Substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located; Determining an elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the estimated coordinates of the target point; If the elevation coordinate difference is less than or equal to a coordinate difference threshold, the estimated elevation coordinate is determined to be the three-dimensional global coordinate of the target point to be located.

7. The method according to claim 6, characterized in that After determining the elevation coordinate difference between the updated elevation coordinate and the estimated elevation coordinate in the estimated coordinate of the target point, the method further includes: If the elevation coordinate difference is greater than a coordinate difference threshold, updating the estimated elevation coordinates in the estimated coordinates of the target point based on the updated elevation coordinates; Based on the updated estimated coordinates of the target point, the process returns to execute substituting the estimated coordinates of the target point into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

8. A positioning device, characterized in that: The positioning device comprises: A ground elevation model determination module is used to determine the global coordinates of feature points of a regional surface of a monocular photography area in a global coordinate system, and to fit a ground surface elevation model according to the global coordinates of the feature points; the monocular photography area includes a target point to be located; An image point coordinate determination module is used to determine the image point coordinates of feature points of the regional surface in the regional image of the monocular photography area in the image coordinate system based on the calibration plate; An exterior orientation element determination module, configured to perform a rear intersection on the image coordinates of the feature points and the global coordinates of the feature points to determine exterior orientation elements; An estimated coordinate determination module is used to determine the height distance between the monocular camera and the ground, and use the central projection constellation equation to determine the estimated coordinates of the target point to be located in the global coordinate system according to the exterior orientation elements and the height distance between the monocular camera and the ground; The three-dimensional global coordinate determination module is used to determine the three-dimensional global coordinates of the target point to be located based on the ground surface elevation model and the estimated coordinates of the target point.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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