Positioning method and apparatus, computer device, and storage medium

Abstract

The application 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 regional surface feature points in a monocular photography region in a global coordinate system, and fitting a ground surface elevation model according to the feature point global coordinates; acquiring a calibration board image collected by a monocular camera, and determining feature point image point coordinates of the regional surface feature points in an image coordinate system based on the calibration board image; performing resection on the feature point image point coordinates and the feature point global coordinates, and determining exterior orientation elements; determining a height distance between the monocular camera and the ground, and determining target point estimated coordinates of a 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 a central projection conformation equation; and determining three-dimensional global coordinates of the target point to be positioned according to the ground surface elevation model and the target point estimated coordinates. The above scheme improves the positioning accuracy of the target point to be positioned.

Description

Technical Field

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

[0002] Currently, satellite positioning is the most common technology for target localization. Its pseudorange positioning accuracy can typically reach the meter level, while RTK (Real-time Kinematics) technology within satellite positioning can achieve centimeter-level accuracy. However, satellite positioning is susceptible to signal interference, making it almost impossible to apply in canyons or indoor environments. In scenarios where satellite signals are blocked, Wi-Fi positioning and UWB (Ultra-Wideband) are widely used in the field of positioning technology to achieve rapid target localization. Wi-Fi positioning determines location through RSSI (Received Signal Strength Indicator) or fingerprint matching, making it suitable for indoor scenarios with minimal changes in environment. UWB, on the other hand, uses triangulation with at least three base stations to determine the target's location, offering high accuracy and is often used in high-precision scenarios such as factories and hospitals, but it is more expensive and susceptible to multipath interference. Therefore, achieving high-precision and low-cost target localization while avoiding signal interference during the localization process is a problem that needs to be solved. Summary of the Invention

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

[0004] Firstly, this application provides a positioning method, the method comprising:

[0005] Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located;

[0006] Based on the calibration board, determine the image coordinates of the feature points of the region surface in the image of the monocular photography area in the image-side coordinate system.

[0007] The image point coordinates of the feature point and the global coordinates of the feature point are re-intersected to determine the exterior orientation elements;

[0008] The height distance between the monocular camera and the ground is determined. Using the central projection modeling equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground.

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

[0010] In one embodiment, based on a calibration plate, the image coordinates of feature points of the region surface in the monocular imaging region are determined in the image-side coordinate system, including:

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

[0012] The radial and tangential distortion coefficients are used to correct the distortion of the feature points in the region image. The corrected feature point positions are then corrected using a principal point correction device to determine the image point coordinates.

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

[0014] The global coordinates of the feature points are de-centroided to determine the de-centroided coordinates;

[0015] The polynomial surface model is determined based on the decentrated coordinates;

[0016] The ground surface elevation model is determined by solving the polynomial surface model using the least squares method.

[0017] In one embodiment, the feature point image coordinates and the feature point global coordinates are back-intersected to determine the exterior orientation elements, including:

[0018] The initial values ​​of the exterior orientation elements are determined based on the mean of the global coordinates of the feature points.

[0019] An error equation is constructed based on the image control points of the sample images acquired by the monocular camera. Based on the error equation and the initial values, the element corrections of the exterior orientation elements are determined.

[0020] Based on the element correction number, the feature point image coordinates, and the initial value, determine the exterior orientation element after back intersection of the feature point image coordinates and the feature point global coordinates.

[0021] In one embodiment, an error equation is constructed based on image control points of sample images acquired by a monocular camera, including:

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

[0023] Determine the image point coordinates of the image control point in the image-side coordinate system, and determine the estimated 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.

[0024] An error equation is constructed based on 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] 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.

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

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

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

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

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

[0032] Secondly, this application also provides a positioning device, the device comprising:

[0033] The ground elevation model determination module is used to determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and to fit the ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located.

[0034] The image point coordinate determination module is used to determine the image point coordinates of feature points of the region surface in the image of the monocular photography area in the image-side coordinate system based on the calibration board.

[0035] The exterior orientation element determination module is used to perform a back intersection of the image point coordinates of the feature point and the global coordinates of the feature point to determine the exterior orientation elements.

[0036] The estimated coordinate determination module is used to determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, the estimated coordinates of the target point to be located in the global coordinate system are determined.

[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] Thirdly, this application also provides a computer device, the computer device including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the following steps:

[0039] Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located;

[0040] Based on the calibration board, determine the image coordinates of the feature points of the region surface in the image of the monocular photography area in the image-side coordinate system.

[0041] The image point coordinates of the feature point and the global coordinates of the feature point are re-intersected to determine the exterior orientation elements;

[0042] The height distance between the monocular camera and the ground is determined. Using the central projection modeling equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground.

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

[0044] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0045] Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located;

[0046] Based on the calibration board, determine the image coordinates of the feature points of the region surface in the image of the monocular photography area in the image-side coordinate system.

[0047] The image point coordinates of the feature point and the global coordinates of the feature point are re-intersected to determine the exterior orientation elements;

[0048] The height distance between the monocular camera and the ground is determined. Using the central projection modeling equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground.

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

[0050] The aforementioned positioning method, device, computer equipment, and storage medium determine the global coordinates of feature points on the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; acquire calibration board images collected by the monocular camera, and determine the image coordinates of the feature points on the area surface in the image-side coordinate system based on the calibration board images; perform re-intersection between the image coordinates 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 model equation to determine the estimated coordinates of the target point in the global coordinate system based on the exterior orientation elements and the height distance between the monocular camera and the ground; and determine the three-dimensional global coordinates of the target point based on the ground surface elevation model and the estimated coordinates of the target point. This solves the problem of low positioning accuracy caused by signal interference when directly locating a target using satellite positioning technology, and also solves the problem of high cost and susceptibility to signal interference when determining the target position using triangulation with multiple base stations. The above scheme determines the global coordinates of feature points in the global coordinate system based on the calibration board image acquired by the monocular camera, and determines the image coordinates of the feature points in the image-side coordinate system. It then fits a ground surface elevation model based on the global coordinates of the feature points, determines the exterior orientation elements based on the image coordinates and global coordinates of the feature points, and finally determines the three-dimensional global coordinates of the target point to be located based on the height distance between the monocular camera and the ground using the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point, avoiding signal interference, and reducing positioning costs. Attached Figure Description

[0051] Figure 1 This is a diagram illustrating the application environment of the positioning method in one embodiment;

[0052] Figure 2 This is a flowchart illustrating the positioning method in one embodiment;

[0053] Figure 3 This is a flowchart illustrating a method for determining the elevation model of a ground surface in one embodiment;

[0054] Figure 4 This is a flowchart illustrating the positioning method in another embodiment;

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

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

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

[0058] Figure 8 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0060] The positioning method provided in this application embodiment can be applied to, for example, Figure 1In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104, or it can be located in the cloud or on another network server. Server 104 determines the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fits a ground surface elevation model based on the global coordinates of the feature points. The monocular imaging area contains a target point to be located. Based on a calibration board, the image coordinates of the feature points of the area in the monocular imaging area in the image-side coordinate system are determined. The image coordinates of the feature points and the global coordinates of the feature points are re-intersected to determine the exterior orientation elements. The height distance between the monocular camera and the ground is determined. Using the central projection model, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground. Based on the ground surface elevation model and the estimated coordinates of the target point, the three-dimensional global coordinates of the target point to be located are determined, and the three-dimensional global coordinates of the target point to be located are sent to terminal 102 through a communication network. Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, smart vehicle devices, etc. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. Server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers.

[0061] In one embodiment, such as Figure 2 As shown, a positioning method is provided. This embodiment illustrates the application of this method to a terminal. It is understood that this method can also be applied to a server, and further to a system including both a terminal and a server, and is implemented through interaction between the terminal and the server. In this embodiment, the method includes the following steps:

[0062] S210. Determine the global coordinates of the feature points 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.

[0063] The monocular imaging area contains the target point to be located.

[0064] In photography, the monocular imaging area refers to the shooting area of ​​a monocular camera. In photography, area feature points typically refer to regions in an image with distinct visual characteristics. These regions, through elements such as shape, texture, and contrast, form visual focal points, guiding the viewer's eye and enhancing the image's expressiveness. The global coordinate system refers to the coordinate system used for RTK positioning, i.e., the satellite positioning coordinate system. The coordinates of an object determined in the global coordinate system are generally latitude and longitude coordinates. The target point to be located refers to the feature points corresponding to the target object that needs to be located. The ground surface elevation model is a mathematical model that describes the elevation of a ground surface; 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 monocular imaging area in the global coordinate system, and a ground surface elevation model is fitted based on the global coordinates of the feature points. Preferably, the number of feature points of the monocular imaging area is greater than or equal to 6.

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

[0067] The global coordinates of the feature points are de-centroided to determine the de-centroided coordinates; the polynomial surface model is determined based on the de-centroided 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 feature points are uniformly distributed throughout the monocular imaging area. Decentrifugation of image feature points typically refers to the process in image processing where the centroid coordinates of feature points are calculated, and then used as a reference for coordinate transformation or normalization to eliminate coordinate offsets caused by image rotation and scaling.

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

[0070] (1)

[0071] Where (X,Y,Z) refers to the de-centroided 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 feature points on the surface of the monocular photography area is at least 6. Substituting the de-centroided coordinates of the feature points on the surface into formula (1), and solving formula (1) by 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 elevation model of the ground surface.

[0072] The above scheme provides a way to construct a ground surface elevation model. It determines the polynomial surface model based on the decentrified coordinates, and determines the ground surface elevation model based on the solution results of the polynomial surface model, thus constructing a simple and effective ground surface elevation model.

[0073] S220. Based on the calibration plate, determine the image coordinates of the feature points of the region surface in the image of the monocular photography area in the image-side coordinate system.

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

[0075] A monocular camera is a vision sensor that continuously outputs images using only one optical system and solid-state imaging device, achieving environmental perception through monocular imaging principles. A monocular camera can be mounted on a vehicle. Its core function is to acquire two-dimensional images through a monocular lens and combine this with computer vision algorithms to estimate three-dimensional information such as the distance and velocity of target objects. A calibration plate is a device used in machine vision, image measurement, photogrammetry, and 3D reconstruction. It uses a plate with a fixed-spacing pattern array to help correct lens distortion, determine the conversion relationship between physical dimensions and pixels, and establish the geometric model of camera imaging. The calibration plate image is the image of the calibration plate captured by the monocular camera. It is mainly used to correct lens distortion, determine the conversion relationship between physical dimensions and pixels, and establish the relationship between points on the surface of spatial objects and their corresponding points in the image. By capturing an image of the plate with a fixed-spacing pattern array and applying calibration algorithms to that image, the geometric model of the camera can be derived, resulting in high-precision measurement and reconstruction results. The plate with the fixed-spacing pattern array is the calibration plate. The monocular imaging area refers to the shooting area of ​​the monocular camera. In photography, area feature points typically refer to regions in an image with distinct visual characteristics. These regions, through elements such as shape, texture, and contrast, form visual focal points, guiding the viewer's eye and enhancing the image's expressiveness. The global coordinate system refers to the coordinate system used for RTK positioning, i.e., the satellite positioning coordinate system. The coordinates of an object determined in the global coordinate system are generally latitude and longitude coordinates. The target point to be located refers to the feature point corresponding to the target object. The image-space coordinate system is the core coordinate system used in photogrammetry to describe the spatial position of image points on a single image. It achieves precise coordinate expression through a right-handed rectangular coordinate system. Image point coordinates refer to the position coordinates of a single pixel in an image; feature point image point coordinates refer to the position coordinates of the pixel corresponding to the feature point, i.e., the coordinates of the feature point in the image-space coordinate system.

[0076] Specifically, the system acquires the regional image of the monocular imaging area captured by the monocular camera, calibrates the coordinates of the feature points of the region surface in the image-side coordinate system based on the calibration plate, and determines the image point coordinates of the feature points of the region surface in the image-side coordinate system.

[0077] For example, methods for determining the coordinates of feature points include:

[0078] Based on the calibration plate, distortion parameters are estimated for the region image of the monocular photography area to determine the radial distortion coefficient and the tangential distortion coefficient. Based on the radial distortion coefficient and the tangential distortion coefficient, the distortion of the feature point position of the region surface in the region image is corrected. Then, the corrected feature point position is corrected by the principal point correction device to determine the image point coordinates of the feature point.

[0079] It should be noted that distortion correction is a technique that corrects image distortion by extracting feature points from the image, establishing a mapping relationship with the real coordinates, and then correcting image distortion. Common methods include model-based correction, feature point matching, and mesh correction. Radial distortion is caused by imperfections in the lens shape, manifesting as stretching or compression of image edges; tangential distortion is caused by the lens not being parallel to the imaging plane, resulting in a straight line tilt in the image.

[0080] Specifically, radial and tangential distortion are primarily determined using Zhang's calibration method. Zhang's calibration method uses a specific pattern on a calibration plate to obtain the correspondence between image coordinates and world coordinates, and then calculates the distortion parameters. Based on the radial and tangential distortion coefficients, distortion correction is performed on the positions of feature points in the regional image. Then, a principal point correction device is used to correct the corrected feature point positions, determining the image coordinates of the feature points. Principal point correction refers to adjusting the position of the principal point to eliminate its deviation from the theoretical position, thereby improving the geometric accuracy of the image. Principal point correction methods mainly include principal point offset and distortion correction. Principal point offset involves accurately measuring the deviation between the actual principal point and the theoretical position through camera calibration and correcting it in aerial triangulation. Distortion correction includes radial distortion, tangential distortion, and film deformation, which are eliminated through mathematical models or equipment calibration.

[0081] It should be noted that Zhang's calibration method uses a planar checkerboard pattern to perform linear solutions and nonlinear optimizations of camera parameters to establish an imaging geometric model and correct lens distortion. For example, the method for determining distortion parameters may include: identifying the corner coordinates on the calibration board image using an image recognition algorithm, generating a homogeneous matrix based on the corner coordinates, and calculating the distortion parameters by combining intrinsic and extrinsic parameters.

[0082] For example, the formulas for correcting feature points on the region surface 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 (X) represents the location of the feature points of the region surface in the calibration plate image; corrected1 Y corrected1 ) represents the position of the feature points of the region surface after correction based on the radial distortion coefficient; k1, k2 and k3 are the radial distortion coefficients; r is the distance between the feature points of the region surface and the center of the calibration plate image.

[0086] Then, based on the tangential distortion coefficient, the positions of the feature points on the region surface after correction based on the radial distortion coefficient are corrected to determine the corrected feature point positions. The formulas for determining the corrected feature point positions are shown in formulas (4) and (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 ) represents the corrected feature point position; p1 and p2 are the tangential distortion coefficients.

[0090] S230. Perform a back intersection of the feature point image 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 six parameters in photogrammetry that determine the spatial position (Xs, Ys, Zs) of the photogrammetric center and the image attitude angles (φ, ω, κ). These parameters are used to establish the spatial geometric relationship between the image and the actual object.

[0092] For example, the method for determining the exterior orientation element is as follows:

[0093] The initial values ​​of the exterior orientation elements are determined based on the mean of the global coordinates of the feature points; an error equation is constructed based on the image control points of the sample images acquired by the monocular camera; the element corrections of the exterior orientation elements are determined based on the error equation and the initial values; and the exterior orientation elements are determined by back intersection of the feature point image coordinates and the global coordinates of the feature points based on the element corrections, the feature point image coordinates, and the initial values.

[0094] In this context, corrections typically refer to adjustments made to the original observations to eliminate observation errors. Their core function is to correct the observed values ​​to theoretical values ​​using mathematical models or algorithms, thereby improving measurement accuracy. Photographic control points are control points established and measured on-site for photogrammetry or mapping purposes. Sample images can be historical images captured by a monocular camera. Photographic control points can be set according to the actual needs of the scene.

[0095] Specifically, the mean of the global coordinates of the feature points is used as the initial value of the exterior orientation elements; that is, the mean of the x-coordinates of the global coordinates of the feature points is used as the initial value of the x-coordinates of the exterior orientation elements, and the mean of the y-coordinates of the global coordinates of the feature points is used as the initial value of the y-coordinates of the exterior orientation elements. An error equation is constructed based on the image control points of the sample images acquired by the monocular camera. The initial values ​​of the exterior orientation elements are input into the error equation, and the element corrections for the exterior orientation elements are calculated based on the error equation. Based on the element corrections, the image coordinates of the feature points, and the initial values, the exterior orientation elements are determined after back-intersection of the image coordinates of the feature points and the global coordinates of the feature points.

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

[0097] (6)

[0098] Where (x, y) are the coordinates of the feature point image; (x0, y0) are the initial values ​​of the exterior orientation elements; The element correction number for the exterior orientation element; For the exterior orientation elements that need to be determined.

[0099] The above scheme proposes a method for calculating exterior orientation elements. Based on the element correction, feature point image coordinates, and initial values, the exterior orientation elements are determined by re-intersection of the feature point image coordinates and the global coordinates of the feature points, which can improve the accuracy of the exterior orientation elements.

[0100] For example, an error equation is constructed based on the image control points of sample images acquired by a monocular camera, including:

[0101] Determine the image control points of the sample images acquired by the monocular camera, and determine the global coordinates of the image control points in the global coordinate system; determine the image point coordinates of the image control points in the image-side coordinate system, and determine the estimated coordinates of the image control points based on the image point coordinates, feature point coordinates, and the height distance between the monocular camera and the ground; construct an error equation based on the estimated coordinates and global coordinates of the control points.

[0102] The above scheme provides a method for constructing error equations. The element corrections of the exterior orientation elements are solved based on the constructed error equations. Solving for the exterior orientation elements based on the element corrections can improve the reliability of the exterior orientation elements.

[0103] S240. Determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, determine the estimated coordinates of the target point in the global coordinate system based on 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 an approximate height distance between the monocular camera and the ground.

[0105] Specifically, the approximate height distance h between the monocular camera and the ground is determined, the difference between Zs in the exterior orientation element and the approximate height distance h is determined, and the inverse of the central projection modeling equation, as well as the difference between the vertical coordinate and the height distance in the exterior orientation element, is used to determine the estimated coordinates of the target point in the global coordinate system.

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

[0107] (7)

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

[0109] Where (x,y) are the coordinates of the feature point image; r is an element of the orthogonal matrix generated by the three exterior orientation elements of the camera; and f is a coefficient.

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

[0111] For example, 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 of the target point; if the elevation coordinate difference is less than or equal to the coordinate difference threshold, then determine the estimated elevation coordinates as the three-dimensional global coordinates of the target point to be located.

[0113] Specifically, the approximate planar coordinates (X, X) of the target point to be located can be calculated according to formulas (7) and (8). p ,Y p ), approximate planar coordinates (X p ,Y p Substituting the values ​​into the ground surface elevation model, the updated elevation coordinates of the target point to be located can be obtained. The system determines the elevation coordinate difference between the updated elevation coordinates and the estimated elevation coordinates of the target point. If the elevation coordinate difference is less than or equal to the coordinate difference threshold, the estimated elevation coordinates are determined as the three-dimensional global coordinates 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's estimated coordinates. This can reduce the cost of locating the target point while ensuring positioning accuracy.

[0115] For example, if the elevation coordinate difference is greater than the coordinate difference threshold, the estimated elevation coordinates in the target point's estimated coordinates are updated based on the updated elevation coordinates; based on the updated target point's estimated coordinates, the process returns to substitute the target point's estimated coordinates into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

[0116] The above scheme iteratively updates the estimated coordinates of the target point when the elevation coordinate difference is greater than the coordinate difference threshold, and recalculates the updated elevation coordinates of the target point to be located 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 of the target point 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 feature points of the monocular imaging area in the global coordinate system are determined, and a ground surface elevation model is fitted based on the global coordinates of the feature points. The calibration board image captured by the monocular camera is acquired, and based on the calibration board image, the image coordinates of the feature points in the image-side coordinate system are determined. The image coordinates of the feature points and the global coordinates of the feature points are re-intersected to determine the exterior orientation elements. The height distance between the monocular camera and the ground is determined, and using the central projection model equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground. Finally, the three-dimensional global coordinates of the target point 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 locating a target using satellite positioning technology, and also solves the problem of high cost and susceptibility to signal interference when determining the target position using triangulation with multiple base stations. The above scheme determines the global coordinates of feature points in the global coordinate system based on the calibration board image acquired by the monocular camera, and determines the image coordinates of the feature points in the image-side coordinate system. It then fits a ground surface elevation model based on the global coordinates of the feature points, determines the exterior orientation elements based on the image coordinates and global coordinates of the feature points, and finally determines the three-dimensional global coordinates of the target point to be located based on the height distance between the monocular camera and the ground using the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point, avoiding signal interference, and reducing positioning costs.

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

[0119] The global coordinates of feature points are decentrifuged to determine the decentrifuged coordinates. A polynomial surface model is then determined based on these coordinates. The ground surface elevation model is determined by solving the polynomial surface model using the least squares method. Radial and tangential distortion coefficients are determined from the calibration plate image. Based on these coefficients, distortion correction is performed on the positions of feature points on the region surface within the calibration plate image. Finally, a principal point correction device is used to correct the principal point positions of the corrected feature points, thus determining their image point coordinates.

[0120] Determine the image control points of the sample images acquired by the monocular camera, and determine the global coordinates of the image control points in the global coordinate system; determine the image point coordinates of the image control points in the image-side coordinate system, and determine the estimated coordinates of the image control points based on the image point coordinates, feature point coordinates, and the height distance between the monocular camera and the ground; construct an error equation based on the estimated coordinates and global coordinates of the control points.

[0121] The mean of the global coordinates of the feature points is used as the initial value of the exterior orientation elements. An error equation is constructed based on the image control points of the sample images acquired by the monocular camera. The initial values ​​of the exterior orientation elements are input into the error equation, and the element corrections of the exterior orientation elements are calculated based on the error equation. Based on the element corrections, the image coordinates of the feature points, and the initial values, the exterior orientation elements after back-intersection of the image coordinates of the feature points and the global coordinates of the feature points are determined.

[0122] Determine the height distance between the monocular camera and the ground, determine the difference between the vertical coordinates and the height distance in the exterior orientation elements, and use the inverse of the central projection model equation and the difference between the vertical coordinates and the height distance in the exterior orientation elements to determine the estimated coordinates of the target point 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 coordinate difference between the updated elevation coordinates and the estimated elevation coordinates in the target point's estimated coordinates; if the elevation coordinate difference is less than or equal to a coordinate difference threshold, then determine the estimated elevation coordinates as the three-dimensional global coordinates of the target point to be located. If the elevation coordinate difference is greater than the coordinate difference threshold, then 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 the process of 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.

[0124] In the above positioning method, the global coordinates of the feature points of the monocular imaging area in the global coordinate system are determined, and a ground surface elevation model is fitted based on the global coordinates of the feature points. The calibration board image captured by the monocular camera is acquired, and based on the calibration board image, the image coordinates of the feature points in the image-side coordinate system are determined. The image coordinates of the feature points and the global coordinates of the feature points are re-intersected to determine the exterior orientation elements. The height distance between the monocular camera and the ground is determined, and using the central projection model equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground. Finally, the three-dimensional global coordinates of the target point 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 locating a target using satellite positioning technology, and also solves the problem of high cost and susceptibility to signal interference when determining the target position using triangulation with multiple base stations. The above scheme determines the global coordinates of feature points in the global coordinate system based on the calibration board image acquired by the monocular camera, and determines the image coordinates of the feature points in the image-side coordinate system. It then fits a ground surface elevation model based on the global coordinates of the feature points, determines the exterior orientation elements based on the image coordinates and global coordinates of the feature points, and finally determines the three-dimensional global coordinates of the target point to be located based on the height distance between the monocular camera and the ground using the central projection conformation equation and the ground surface elevation model, thereby improving the positioning accuracy of the target point, avoiding signal interference, and reducing positioning costs.

[0125] For example, 11 surface feature points are collected in the photographed area. Seven of these are used to fit the ground surface elevation model, and the remaining four (the feature points within the rectangular frame) are used to verify the positioning accuracy. The 11 surface feature points are as follows: Figure 5 As shown in Table 1, the positioning accuracy is as follows.

[0126] Table 1

[0127]

[0128] For example, 14 surface feature points are collected in the photographed area. Nine of these are used to fit the ground surface elevation model, and the remaining five (the feature points within the rectangular frame) are used to verify the positioning accuracy. The distribution of the 14 surface feature points is as follows: Figure 6 As shown in Table 2, the positioning accuracy is as follows.

[0129] Table 2

[0130]

[0131] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0132] Based on the same inventive concept, this application also provides a positioning device for implementing the positioning method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more positioning device embodiments provided below can be found in the limitations of the positioning method described above, and will not be repeated here.

[0133] In one embodiment, such as Figure 7 As shown, a positioning device is provided, including: a ground elevation model determination module 501, an image 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 used to determine the global coordinates of the feature points of the monocular photography area in the global coordinate system, and to fit 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.

[0135] Image point coordinate determination module 502 is used to determine the image point coordinates of feature points of the region surface in the image of the monocular photography area in the image-side coordinate system based on the calibration plate.

[0136] The exterior orientation element determination module 503 is used to perform a back intersection of the feature point image point coordinates and the feature point global coordinates to determine the exterior orientation elements.

[0137] The estimated coordinate determination module 504 is used to determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, the estimated coordinates of the target point to be located in the global coordinate system are determined.

[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 based on the ground surface elevation model and the estimated coordinates of the target point.

[0139] For example, the point coordinate determination module 502 is specifically used for:

[0140] Based on the calibration plate, distortion parameters are estimated for the region image of the monocular photography area 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 positions of the regional surface feature points in the regional image are distorted and corrected. Then, the image point coordinates of the feature points are determined by using an image principal point correction device to correct the image principal points of the corrected feature point positions.

[0142] Furthermore, the ground elevation model determination module 501 is specifically used for:

[0143] The global coordinates of the feature points are de-centroided to determine the de-centroided coordinates;

[0144] The polynomial surface model is determined based on the decentrated coordinates;

[0145] The ground surface elevation model is determined by solving the polynomial surface model using the least squares method.

[0146] For example, the exterior orientation element determination module 503 is specifically used for:

[0147] The initial values ​​of the exterior orientation elements are determined based on the mean of the global coordinates of the feature points.

[0148] An error equation is constructed based on the image control points of the sample images acquired by the monocular camera. Based on the error equation and the initial values, the element corrections of the exterior orientation elements are determined.

[0149] Based on the element correction number, the feature point image coordinates, and the initial value, determine the exterior orientation element after back intersection of the feature point image coordinates and the feature point global coordinates.

[0150] For example, the exterior orientation element determination module 503 is also specifically used for:

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

[0152] Determine the image point coordinates of the image control point in the image-side coordinate system, and determine the estimated 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.

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

[0154] For example, the three-dimensional global coordinate determination module 505 is specifically used for:

[0155] 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.

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

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

[0158] For example, the three-dimensional global coordinate determination module 505 is also specifically used for:

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

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

[0161] Each module in the aforementioned positioning device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0162] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 8As shown, the computer device includes a processor, memory, input / output interfaces, a communication interface, a display unit, and an input device. The processor, memory, and input / output interfaces are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interfaces. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The input / output interfaces are used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through 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 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 an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

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

[0164] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0165] Step 1: Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located.

[0166] Step 2: Acquire the calibration board image captured by the monocular camera, and based on the calibration board image, determine the image coordinates of the feature points of the region surface in the image-side coordinate system;

[0167] Step 3: 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;

[0168] Step 4: Determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, determine the estimated coordinates of the target point in the global coordinate system.

[0169] 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.

[0170] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0171] Step 1: Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located.

[0172] Step 2: Acquire the calibration board image captured by the monocular camera, and based on the calibration board image, determine the image coordinates of the feature points of the region surface in the image-side coordinate system;

[0173] Step 3: 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;

[0174] Step 4: Determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, determine the estimated coordinates of the target point in the global coordinate system.

[0175] 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.

[0176] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0177] Step 1: Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located.

[0178] Step 2: Acquire the calibration board image captured by the monocular camera, and based on the calibration board image, determine the image coordinates of the feature points of the region surface in the image-side coordinate system;

[0179] Step 3: 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;

[0180] Step 4: Determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, determine the estimated coordinates of the target point in the global coordinate system.

[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, data stored, data displayed, 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 related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0183] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, 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 many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0184] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0185] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A positioning method, characterized in that, include: Determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and fit a ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located; Based on the calibration board, determine the image coordinates of the feature points of the region surface in the image of the monocular photography area in the image-side coordinate system. The image coordinates of the feature points and the global coordinates of the feature points are re-intersected to determine the exterior orientation elements; the exterior orientation elements include the spatial position of the photogrammetric center and the image pose angle determined in photogrammetry. The height distance between the monocular camera and the ground is determined. Using the central projection modeling equation, the estimated coordinates of the target point in the global coordinate system are determined based on the exterior orientation elements and the height distance between the monocular camera and the ground. Based on the ground surface elevation model and the estimated coordinates of the target point, 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, the three-dimensional global coordinates of the target point to be located are determined, including: 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 of the target point; If the elevation coordinate difference is less than or equal to the coordinate difference threshold, then the estimated elevation coordinates are determined to be the three-dimensional global coordinates of the target point to be located. After determining the elevation coordinate difference between the updated elevation coordinates and the estimated elevation coordinates of the target point, the method further includes: If the elevation coordinate difference is greater than the coordinate difference threshold, then the estimated elevation coordinates in the estimated coordinates of the target point are updated based on the updated elevation coordinates; Based on the updated target point estimated coordinates, return to the process of substituting the target point estimated coordinates into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

2. The method according to claim 1, characterized in that, Based on the calibration board, the image coordinates of feature points of the region surface in the monocular imaging area are determined in the image-side coordinate system, including: Based on the calibration plate, distortion parameters are estimated for the region image of the monocular photography area to determine the radial distortion coefficient and the tangential distortion coefficient; The radial and tangential distortion coefficients are used to correct the distortion of the feature points in the region image. The corrected feature point positions are then corrected using a principal point correction device to determine the image point coordinates.

3. The method according to claim 1, characterized in that, Fitting a ground surface elevation model based on the global coordinates of the feature points includes: The global coordinates of the feature points are de-centroided to determine the de-centroided coordinates; The polynomial surface model is determined based on the decentrated coordinates; The ground surface elevation model is determined by solving the polynomial surface model using the least squares method.

4. The method according to claim 1, characterized in that, The exterior orientation elements are determined by performing a back intersection between the image point coordinates of the feature point and the global coordinates of the feature point, including: The initial values ​​of the exterior orientation elements are determined based on the mean of the global coordinates of the feature points. An error equation is constructed based on the image control points of the sample images acquired by the monocular camera. Based on the error equation and the initial values, the element corrections of the exterior orientation elements are determined. Based on the element correction number, the feature point image coordinates, and the initial value, determine the exterior orientation element after back intersection of the feature point image coordinates and the feature point global coordinates.

5. The method according to claim 4, characterized in that, An error equation is constructed based on the image control points of sample images acquired by a monocular camera, including: Determine the image control points of the sample images acquired by the monocular camera, and determine the global coordinates of the image control points in the global coordinate system; Determine the image point coordinates of the image control point in the image-side coordinate system, and determine the estimated 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. An error equation is constructed based on the estimated coordinates of the control points and the global coordinates of the control points.

6. A positioning device, characterized in that, The positioning device includes: The ground elevation model determination module is used to determine the global coordinates of the feature points of the monocular imaging area in the global coordinate system, and to fit the ground surface elevation model based on the global coordinates of the feature points; the monocular imaging area contains the target point to be located. The image point coordinate determination module is used to determine the image point coordinates of feature points of the region surface in the image of the monocular photography area in the image-side coordinate system based on the calibration board. The exterior orientation element determination module is used to perform a back intersection of the image point coordinates of the feature point and the global coordinates of the feature point to determine the exterior orientation elements. The estimated coordinate determination module is used to determine the height distance between the monocular camera and the ground. Using the central projection modeling equation, based on the exterior orientation elements and the height distance between the monocular camera and the ground, the estimated coordinates of the target point to be located in the global coordinate system are determined. 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. Based on the ground surface elevation model and the estimated coordinates of the target point, the three-dimensional global coordinates of the target point to be located are determined, including: 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 of the target point; If the elevation coordinate difference is less than or equal to the coordinate difference threshold, then the estimated elevation coordinates are determined to be the three-dimensional global coordinates of the target point to be located. After determining the elevation coordinate difference between the updated elevation coordinates and the estimated elevation coordinates of the target point, the method further includes: If the elevation coordinate difference is greater than the coordinate difference threshold, then the estimated elevation coordinates in the estimated coordinates of the target point are updated based on the updated elevation coordinates; Based on the updated target point estimated coordinates, return to the process of substituting the target point estimated coordinates into the ground surface elevation model to determine the updated elevation coordinates of the target point to be located.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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