Regional surface displacement monitoring method and system based on Beidou and computer vision

Abstract

The embodiment of the present application discloses a method and system for regional surface displacement monitoring based on Beidou and computer vision, wherein Beidou is used to locate and measure a first target integrated with a Beidou receiver, and a camera is used to photograph the first target, and the camera's position and posture are calculated. At the same time, the camera photographs a third target that is not integrated with the Beidou receiver, and the coordinates of the third target are calculated. This method solves the problem that the surface displacement monitoring technology based on Beidou satellite positioning cannot accurately locate in scenes with weak satellite signals in existing surface displacement monitoring methods, and can provide early warnings for the occurrence of geological disasters, avoid casualties and property losses, and can also correct the influence of systematic errors caused by changes in the position and posture of the camera and the first target itself.

Description

Technical Field

[0001] The present application relates to the technical field of surface displacement monitoring, and in particular to a method and system for regional surface displacement monitoring based on Beidou and computer vision. Background Art

[0002] Beidou satellite navigation system has been widely used in the field of surface displacement monitoring. Surface displacement monitoring can provide early warning of geological disasters at critical moments to avoid casualties and property losses.

[0003] Beidou satellite navigation and positioning receivers can use real-time kinematic (RTK) differential technology to perform millimeter-level high-precision surface displacement monitoring of monitoring points. However, due to the limitations of Beidou satellite positioning principles, the monitoring points must be located in places where the Beidou satellite signal is open and unobstructed.

[0004] Although the vision-based surface displacement monitoring method can also be used for high-precision measurement and monitoring of surface displacement and is not limited by the requirements of the Beidou satellite signal observation environment, the current computer vision-based surface displacement detection method cannot correct the systematic error caused by the posture changes of the camera and the reference target itself, and can only detect the displacement changes of the target to be measured in the horizontal and vertical directions of the vertical plane where it is located. Summary of the invention

[0005] The present application aims to at least solve the technical problems existing in the prior art. To this end, the present application proposes a method and system for regional surface displacement monitoring based on Beidou and computer vision, which can correct the systematic error caused by the change of the position of the camera and the first target itself, and can also solve the problem that the surface displacement monitoring technology of Beidou satellite positioning cannot accurately locate in scenes with weak satellite signals.

[0006] In a first aspect of the present application, a method for regional surface displacement monitoring based on Beidou and computer vision is provided, which is applicable to surface displacement monitoring of monitoring points in a monitoring area, wherein first-level monitoring points, second-level monitoring points and third-level monitoring points are set in the monitoring area, the number of the first-level monitoring points is at least three and each of the first-level monitoring points is provided with a receiver integrating a first target, the third-level monitoring points are provided with a third target, and the second-level monitoring points are provided with a camera and the field of view of the camera covers all the first targets and the third targets; the method comprises:

[0007] Acquire the Beidou positioning signals received by all the receivers, and calculate the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals;

[0008] Acquire an image captured by the camera, and calculate the two-dimensional coordinates of each of the first targets and the third target in the image coordinate system according to the image; and calculate the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system;

[0009] Calculating a third three-dimensional coordinate of the third target according to the first three-dimensional coordinate of the first target, the two-dimensional coordinate of the first target in the image coordinate system, and the two-dimensional coordinate of the third target in the image coordinate system;

[0010] The surface displacement changes of all the first-level monitoring points, the second-level monitoring points and the third-level monitoring points are calculated according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after.

[0011] The first aspect of the present application has at least the following beneficial effects:

[0012] (1) This method integrates BeiDou and computer vision to solve the limitation of using only one monitoring solution in a certain monitoring project. It can obtain the surface displacement changes of multiple monitoring points, provide early warning for the occurrence of geological disasters, and avoid casualties and property losses.

[0013] (2) This method directly uses Beidou positioning technology to locate the first target, and continuously corrects it through Beidou positioning; by deploying cameras and photographing at least three first targets, the camera's attitude can be determined, because the coordinates of the three reference targets can be continuously corrected through Beidou positioning, and thus, the camera's attitude can also be corrected. Therefore, this method can correct the influence of systematic errors caused by changes in the position and attitude of the camera and the first target itself.

[0014] (3) The problem that the surface displacement monitoring technology based on Beidou satellite positioning cannot accurately locate in scenarios with weak satellite signals is solved.

[0015] According to some embodiments of the present application, the acquiring of the Beidou positioning signals received by all the receivers, and calculating the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals, includes:

[0016] Acquire reference coordinates and differential data received by the receiver and broadcast by a Beidou continuously operating reference station network covering the monitoring area;

[0017] Performing baseline solution according to the reference coordinates and the differential data to obtain the three-dimensional coordinates of the antenna of the receiver;

[0018] According to the coordinate relationship between the antenna of each receiver and the corresponding first target, the first three-dimensional coordinates of each first target in the CGCS2000 geodetic coordinate system are calculated respectively.

[0019] According to some embodiments of the present application, calculating the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system includes:

[0020] establishing an image coordinate system according to the image;

[0021] According to each imaging point of the first target and the third target on the image, the two-dimensional coordinates of each of the first target and the third target on the image coordinate system are calculated.

[0022] According to some embodiments of the present application, the number of the first-level monitoring points is three.

[0023] According to some embodiments of the present application, calculating the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system includes:

[0024] Let the second three-dimensional coordinate of the camera in the CGCS2000 geodetic coordinate system be c=[X O ,Y O ,Z O ]; let the first three-dimensional coordinate of the first target be [X A ,Y A ,Z A ], the first three-dimensional coordinate of the second first target is [X B ,Y B ,Z B ], the first three-dimensional coordinate of the third first target is [X C ,Y C ,Z C ];

[0025] According to [X A ,Y A ,Z A ],[X B ,Y B ,Z B ],[X C ,Y C ,Z C ], we can calculate:

[0026]

[0027]

[0028]

[0029] in, Indicates [X A ,Y A ,Z A ] and [X B ,Y B ,Z B ] is the square of the straight-line distance between them; Indicates [X B ,Y B ,Z B ] and [X C ,Y C ,Z C ] is the square of the straight-line distance between them; Indicates [X C ,Y C ,Z C ] and [X A ,Y A ,Z A ] is the square of the straight-line distance between A Indicates [X A ,Y A ,Z A ] and [X O ,Y O ,Z O ]; x B Indicates [X B ,Y B ,Z B ] and [X O ,Y O ,Z O ]; x C Indicates [X C ,Y C ,Z C ] and [X O ,Y O ,Z O ]; cosθ AB Indicates angle θ AB The cosine value of BC Indicates angle θ BC The cosine value of CA Indicates angle θ CA The cosine of the angle θ AB Indicates [X A ,Y A ,Z A ]、[X B ,Y B ,Z B ] respectively with [X O,Y O ,Z O ]; angle θ BC Indicates [X B ,Y B ,Z B ]、[X C ,Y C ,Z C ] respectively with [X O ,Y O ,Z O ]; angle θ CA Indicates [X C ,Y C ,Z C ]、[X A ,Y A ,Z A ] respectively with [X O ,Y O ,Z O ]The angle between the connecting lines;

[0030] Solve according to Wu's elimination method The following system of equations is obtained:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] Among them, a i is a polynomial f(x A ), b i is a polynomial f(x B ), c i is a polynomial f(x C ) coefficient;

[0038] Solving the equations, we get c = [X O ,Y O ,Z O ]’s value.

[0039] According to some embodiments of the present application, calculating the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system includes:

[0040] Let the third three-dimensional coordinate of the third target in the CGCS2000 geodetic coordinate system be And according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system, the following three formulas are constructed:

[0041]

[0042]

[0043]

[0044] Among them, T i represents a target center of the third target; express With [X O ,Y O ,Z O ] the straight-line distance between Indicates [X A ,Y A ,Z A ]、 Respectively with [X O ,Y O ,Z O ]The angle between the lines; angle Indicates [X B ,Y B ,Z B ]、 With [X O ,Y O ,Z O ] respectively connected by the angle; angle Indicates [X C ,Y C ,Z C ]、 Respectively with [X O ,Y O ,Z O ]The angle between the connecting lines;

[0045] Solving the above three formulas, we get The value of .

[0046] According to some embodiments of the present application, the calculating the surface displacement changes of all the first-level monitoring points, the second-level monitoring points, and the third-level monitoring points according to the first three-dimensional coordinates, the second three-dimensional coordinates, and the third three-dimensional coordinates measured twice before and after includes:

[0047] The first three-dimensional coordinates of the latter measurement are differentiated from the first three-dimensional coordinates of the previous measurement to obtain the surface displacement change in the east, north and altitude directions projected with the first three-dimensional coordinates of the first-level monitoring point of the previous measurement as the origin;

[0048] The second three-dimensional coordinates of the latter measurement are differentiated from the second three-dimensional coordinates of the previous measurement to obtain the surface displacement change in the east, north and altitude directions projected with the first three-dimensional coordinates of the second-level monitoring point of the previous measurement as the origin;

[0049] The third three-dimensional coordinates of the latter measurement are differentiated from the third three-dimensional coordinates of the previous measurement to obtain the surface displacement change projected in the east, north and height directions with the first three-dimensional coordinates of the third-level monitoring point of the previous measurement as the origin.

[0050] In a second aspect of the present application, a regional surface displacement monitoring system based on Beidou and computer vision is provided, the system comprising:

[0051] At least three receivers, each of which is installed at a different first-level monitoring point in the monitoring area, and each of which is integrated with a first target;

[0052] at least one third target, the third target being installed at a third-level monitoring point within the monitoring area;

[0053] A camera is installed at a second-level monitoring point in the monitoring area, and the field of view of the camera covers all of the first targets and the third targets;

[0054] A processor is used to obtain Beidou positioning signals received by all the receivers, and calculate the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals; and to obtain the image taken by the camera, and calculate the two-dimensional coordinates of each of the first targets and the third target in the image coordinate system according to the image; and calculate the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system; and to calculate the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system; and to calculate the surface displacement change of all the first-level monitoring points, the second-level monitoring points and the third-level monitoring points according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after.

[0055] According to a third aspect of the present application, an electronic device is provided, including:

[0056] at least one memory;

[0057] at least one processor;

[0058] at least one computer program;

[0059] The computer program is stored in the memory, and the processor executes at least one computer program to implement: the regional surface displacement monitoring method based on Beidou and computer vision as described above.

[0060] In a fourth aspect of the present application, a computer-readable storage medium is provided, storing computer-executable instructions, wherein the computer-executable instructions are used to execute: the regional surface displacement monitoring method based on Beidou and computer vision as described above.

[0061] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0063] Figure 1 It is a flowchart of a method for monitoring regional surface displacement based on Beidou and computer vision provided in one embodiment of the present application;

[0064] Figure 2 yes Figure 1 A schematic flow chart of step S101 in FIG.

[0065] Figure 3 is a schematic diagram of the positional relationship between two points in a three-dimensional space provided by an embodiment of the present application;

[0066] Figure 4 yes Figure 1 A schematic flow chart of step S104 in FIG.

[0067] Figure 5 is a flowchart of a method for monitoring regional surface displacement based on Beidou and computer vision provided by another embodiment of the present application;

[0068] Figure 6 It is a structural schematic diagram of a regional surface displacement monitoring system based on Beidou and computer vision provided by an embodiment of the present application;

[0069] Figure 7 It is a schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0070] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0071] In the description of this application, if there is a description of first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0072] Landslides, roadbed and railway settlement will cause surface deformation and displacement. The Beidou satellite navigation system has been widely used in the field of surface displacement monitoring. Surface displacement monitoring can provide early warning of geological disasters at critical moments to avoid casualties and property losses.

[0073] Beidou satellite navigation and positioning receivers can use real-time kinematic (RTK) differential technology to perform millimeter-level high-precision surface displacement monitoring of monitoring points. However, due to the limitations of Beidou satellite positioning principles, the monitoring points must be located in places where the Beidou satellite signal is open and unobstructed.

[0074] Although the vision-based surface displacement monitoring method can also be used for high-precision measurement and monitoring of surface displacement, and is not limited to the requirements of the Beidou satellite signal observation environment, the current computer vision-based surface displacement detection method cannot correct the systematic error caused by the position change of the camera and the reference target itself, and can only detect the displacement change of the target to be measured in the horizontal and vertical directions of the vertical plane where it is located. This is because the vision-based surface displacement monitoring method requires the simultaneous observation of two targets (reference target and monitoring target to be monitored). The reference target is arranged at a location with a stable geological environment, assuming that no displacement will occur at all. The monitoring target is arranged at a location where the surface displacement needs to be monitored. At the same time, a camera is arranged at a distance to take pictures of the target, and the surface displacement is measured by comparing the change in the imaging pixel difference of the monitoring target relative to the reference target on the camera imaging plane. However, in high-precision surface displacement measurement, there is no place where the geological environment is completely stable, and the reference target will still have a small displacement change. As time goes by, the position error of the reference target will also increase; in addition, the position of the camera also changes. Since the monitoring target is far away, the error caused by the change in the camera's angle attitude will be amplified.

[0075] In order to solve the above technical defects, refer to Figure 1The embodiment of the present application provides a regional surface displacement monitoring method based on Beidou and computer vision, which is applicable to surface displacement monitoring of monitoring points in a monitoring area, wherein first-level monitoring points, second-level monitoring points and third-level monitoring points are set in the monitoring area, the number of first-level monitoring points is at least three and each first-level monitoring point is provided with a receiver integrating a first target, the third-level monitoring point is provided with a third target, and the second-level monitoring point is provided with a camera and the field of view of the camera covers all the first targets and the third targets; the method comprises:

[0076] Step S101: Obtain Beidou positioning signals received by all receivers, and calculate the first three-dimensional coordinates of each first target according to all Beidou positioning signals.

[0077] Step S102, obtaining an image taken by the camera, and calculating the two-dimensional coordinates of each first target and the third target in the image coordinate system according to the image; and calculating the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system.

[0078] Step S103, calculating the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system.

[0079] Step S104, calculating the surface displacement changes of all first-level monitoring points, second-level monitoring points and third-level monitoring points according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after.

[0080] Reference Figure 2 In some embodiments, in step S101, the Beidou positioning signals received by all receivers are obtained, and the first three-dimensional coordinates of each first target are calculated according to all Beidou positioning signals, including the following steps S1011 to S1013:

[0081] Step S1011: Acquire the reference coordinates and differential data received by the receiver and broadcast by the Beidou continuously operating reference station network covering the monitoring area.

[0082] Step S1012: perform baseline solution according to the reference coordinates and the differential data to obtain the three-dimensional coordinates of the antenna of the receiver.

[0083] Step S1013: According to the coordinate relationship between the antenna of each receiver and the corresponding first target, the first three-dimensional coordinates of each first target in the CGCS2000 geodetic coordinate system are calculated respectively.

[0084] In this embodiment, the first target of the first-level monitoring point is used as a reference target. Each first-level monitoring point has a Beidou satellite navigation positioning receiver, and the receiver is integrated with a first target. The coordinate relationship between the antenna of the receiver and the first target is fixed. The number of first-level monitoring points is at least three (one reference target is required for each correction of the scale change of an azimuth, and for the target that needs to calculate the three-dimensional position change, at least 3 reference targets are required). Here, three receivers and three first targets are preferably set to reduce costs.

[0085] The receiver is connected to the Beidou satellite communication, and the Beidou continuous operation reference station network covering the monitoring area broadcasts the reference coordinates and differential data to the corresponding receiver. After the receiver receives the corresponding signal, these signals can be used to calculate the three-dimensional coordinates of the receiver's antenna in the CGCS2000 geodetic coordinate system (the CGCS2000 geodetic coordinate system is a coordinate system with the center of mass of the earth as the origin). Since the coordinate relationship between the receiver's antenna and the first target is fixed, the first three-dimensional coordinates of the first target can be further known. It should be noted that since the first three-dimensional coordinates of the first target can be located by Beidou, the first three-dimensional coordinates of the first target will be continuously corrected during each measurement. The CGCS2000 geodetic coordinate system is selected by default here. In actual application, it is not limited to this three-dimensional coordinate system, which will not be described in detail here.

[0086] In step S102 of this embodiment, step S102 is divided into two parts. The first part is to first calculate the two-dimensional coordinates of all the first targets and the third targets in the image, which specifically includes the following steps S1021 and S1022:

[0087] Step S1021: Establish an image coordinate system.

[0088] Step S1022: Calculate the two-dimensional coordinates of each of the first target and the third target in the image coordinate system according to the imaging point of each of the first target and the third target in the image.

[0089] The second part is to calculate the second three-dimensional coordinates of the camera using computer vision, that is, to calculate the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system. In some embodiments, the second part specifically includes the following steps S1023 to S1026:

[0090] Step S1023: Let the second three-dimensional coordinate of the camera in the CGCS2000 geodetic coordinate system be c=[X O ,Y O ,Z O ]; let the first first target be A, the second first target be B, and the third first target be C, then the first three-dimensional coordinate of A is [XA ,Y A ,Z A ], the first three-dimensional coordinates of B are [X B ,Y B ,Z B ], the first three-dimensional coordinate of C is [X C ,Y C ,Z C ].

[0091] Assumption: For a point P in three-dimensional space i , whose three-dimensional coordinates in space are p i , the three-dimensional coordinates of the camera's focus O are c, then point P i The straight-line distance from the camera focus O is:

[0092] x i =||p i -c|| (1)

[0093] For a pair of points P in three-dimensional space i and P j ,like Figure 3 As shown, we have:

[0094]

[0095] Where, d ij =||p i -p j || is P i With P j The straight-line distance between ij P i , P j The angles between them and the line connecting the camera focus O.

[0096] Angle θ ij The cosine value of can be calculated by the camera's intrinsic parameter matrix K and the image coordinates of the projection image points of the pair of spatial points on the camera imaging plane:

[0097]

[0098] In the formula, C = (KK T ) -1 ,u i and u j They are three-dimensional space points P i and P j The two-dimensional coordinates of the projected pixel point on the camera imaging plane. Based on this principle, the following step S1024 is introduced.

[0099] Step S1024: According to [X A ,Y A,Z A ],[X B ,Y B ,Z B ],[X C ,Y C ,Z C ], we can calculate:

[0100]

[0101]

[0102]

[0103] in, Indicates [X A ,Y A ,Z A ] and [X B ,Y B ,Z B ] is the square of the straight-line distance between them; Indicates [X B ,Y B ,Z B ] and [X C ,Y C ,Z C ] is the square of the straight-line distance between them; Indicates [X C ,Y C ,Z C ] and [X A ,Y A ,Z A ] is the square of the straight-line distance between A Indicates [X A ,Y A ,Z A ] and [X O ,Y O ,Z O ]; x B Indicates [X B ,Y B ,Z B ] and [X O ,Y O ,Z O ]; x C Indicates [X C ,Y C ,Z C ] and [X O ,Y O ,Z O ]; cosθ AB Indicates angle θ ABThe cosine value of BC Indicates angle θ BC The cosine value of CA Indicates angle θ CA The cosine of the angle θ AB Indicates [X A ,Y A ,Z A ]、[X B ,Y B ,Z B ] respectively with [X O ,Y O ,Z O ]; angle θ BC Indicates [X B ,Y B ,Z B ]、[X C ,Y C ,Z C ] respectively with [X O ,Y O ,Z O ]; angle θ CA Indicates [X C ,Y C ,Z C ]、[X A ,Y A ,Z A ] respectively with [X O ,Y O ,Z O ]The angle between the lines.

[0104] Among them, d AB , d BC , d CA , cosθ AB , cosθ BC , cosθ CA All are known values.

[0105] Step S1025: Eliminate using Wu elimination method to solve The following system of equations is obtained:

[0106]

[0107]

[0108]

[0109] Among them, a i is a polynomial f(x A ), b i is a polynomial f(x B), c i is a polynomial f(x C ). A ) as an example, the x in this equation A has at most 4 real solutions, and x A The approximate distance from the camera to point A and x are measured by the rangefinder. A By comparison, three ambiguous solutions can be eliminated. A For any definite solution, there is a unique positive real number solution x B 、x C Corresponding to it.

[0110]

[0111]

[0112]

[0113] Step S1026: Solve the above equations to calculate the second three-dimensional coordinates of the camera in the CGCS2000 geodetic coordinate system c=[X O ,Y O ,Z O ].

[0114] The cameras deployed at the second-level monitoring points take pictures of all the first targets. The first three-dimensional coordinates of the first targets are known (through Beidou positioning in step S101, and the position of the first targets can be corrected each time positioning is performed). The coordinates of the imaging point of the first target in the camera imaging plane are known (through image and image coordinate system positioning), and the camera's internal parameters have been measured by calibration. According to the camera's imaging model and the principle of spatial point projection, steps S1023 to S1026 calculate the three-dimensional coordinates of the camera focus and the first target in the same three-dimensional coordinate system.

[0115] It should be noted that by deploying cameras to shoot at least three first targets, the camera's attitude can be determined, because the coordinates of the first target can be continuously corrected through Beidou positioning, and thus, the camera's attitude can also be corrected during each measurement process.

[0116] The third target of the third-level monitoring point also has an imaging point on the camera, but the coordinates of the third target are unknown and need to be solved. The posture of the camera (i.e., the focus and imaging plane of the camera in the CGCS2000 geodetic coordinate system) has been determined through the three first targets. Similarly, through the spatial projection principle of the camera, the three-dimensional coordinates of the third target of the third-level monitoring point in the CGCS2000 geodetic coordinate system can be calculated. In step S103 of some embodiments, step S103 specifically includes the following steps S1031 to S1032:

[0117] Step S1031, construct the following three formulas according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system:

[0118]

[0119]

[0120]

[0121] The third three-dimensional coordinates of the third target in the CGCS2000 geodetic coordinate system are: T i represents the target center of the third target; express With [X O ,Y O ,Z O ] between the straight line distance (target center T i Straight-line distance from camera focus O can be measured by a laser rangefinder); angle Indicates [X A ,Y A ,Z A ]、 Respectively with [X O ,Y O ,Z O ]The angle between the lines; angle Indicates [X B ,Y B ,Z B ]、 Respectively with [X O ,Y O ,Z O ]The angle between the lines; angle Indicates [X C ,Y C ,Z C ]、 Respectively with [X O ,Y O ,Z O ]The angle between the lines.

[0122] In the above formula, x A ,x B ,x C , is a known item obtained through measurement or calculation.

[0123] Step S1032: Solve the above three formulas to calculate the third three-dimensional coordinates of the third target in the CGCS2000 geodetic coordinate system.

[0124] Reference Figure 4 In step S104 of some embodiments, step S104 specifically includes the following steps S1041 to S1043:

[0125] Step S1041, differential the first three-dimensional coordinates of the last measurement with the first three-dimensional coordinates of the last measurement, to obtain the surface displacement change in the east, north and height directions projected with the first three-dimensional coordinates of the first-level monitoring point of the last measurement as the origin.

[0126] Step S1042: Differentiate the second three-dimensional coordinates of the last measurement from the second three-dimensional coordinates of the last measurement to obtain the surface displacement change in the east, north and altitude directions with the first three-dimensional coordinates of the second-level monitoring point of the last measurement as the origin.

[0127] Step S1043: Differentiate the third three-dimensional coordinates of the last measurement from the third three-dimensional coordinates of the last measurement to obtain the surface displacement change in the east, north and height directions projected with the first three-dimensional coordinates of the third-level monitoring point of the last measurement as the origin.

[0128] In steps S1041 to S1043, the process includes two measurements. The three-dimensional coordinates of the previous measurement are used as the reference coordinates, and the three-dimensional coordinates of the second measurement are differentiated from the reference coordinates. The surface displacement change projected in the east, north and height directions with the reference coordinates as the origin can be obtained.

[0129] This embodiment has the following beneficial effects:

[0130] (1) This method integrates BeiDou and computer vision to solve the limitation of using only one monitoring solution in a certain monitoring project. It can calculate the surface displacement changes of multiple monitoring points, provide early warning for the occurrence of geological disasters, and avoid casualties and property losses.

[0131] (2) This method uses the three first targets as reference targets, uses Beidou positioning technology to locate the first targets, and can continuously monitor the displacement changes of the first targets (the three-dimensional coordinates of the first targets can be continuously corrected by Beidou positioning); by deploying cameras to shoot the three first targets, the camera's posture can be determined, because the coordinates of the three first targets can be continuously corrected by Beidou positioning, and thus, the camera's posture can also be corrected with each measurement. This application can correct the influence of systematic errors caused by changes in the position and posture of the camera and the first target itself.

[0132] (3) In the positioning process of the third target, the three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image and the two-dimensional coordinates of the third target in the image are used to locate the three-dimensional coordinates of the third target in the CGCS2000 geodetic coordinate system through the spatial projection principle (computer vision) of the camera. This solves the problem that the surface displacement monitoring technology based on Beidou satellite positioning cannot accurately locate in scenes with weak satellite signals in the existing surface displacement monitoring methods.

[0133] (4) The existing vision-based surface displacement monitoring scheme can only detect the displacement change of the target in the horizontal and vertical directions of the vertical plane where it is located. This method can obtain the surface displacement change of the monitoring point in the east, north and height directions.

[0134] In order to facilitate the understanding of those skilled in the art, refer to Figure 5 An embodiment of the present application provides a method for monitoring regional surface displacement based on Beidou and computer vision, and the method includes the following steps S201 to S204:

[0135] Step S201: select three types of monitoring points in the monitoring area, namely, first-level monitoring points, second-level monitoring points and third-level monitoring points.

[0136] Three first-level monitoring points are selected, and all of them are located in areas with good Beidou satellite signal observation environment and no obstructions. Beidou satellite navigation and positioning receivers with integrated image targets are deployed at the first-level monitoring points, and the three-dimensional coordinates of the first-level monitoring points are obtained through Beidou satellite navigation and positioning technology (that is, the three-dimensional coordinates of the target center in the three-dimensional coordinate system).

[0137] At least one second-level monitoring point should be selected, with a camera deployed, and the camera's field of view can cover all first-level monitoring points. The three-dimensional coordinates of the second-level monitoring point (that is, the three-dimensional coordinates of the camera focus in the three-dimensional coordinate system) are obtained by using the two-dimensional plane coordinates of the imaging point of the first-level monitoring point whose three-dimensional coordinates are known on the camera imaging plane, and using computer vision methods. It should be noted that the three-dimensional coordinates measured by the first-level monitoring point, the second-level monitoring point, and the third-level monitoring point are all in the same three-dimensional coordinate system.

[0138] The third-level monitoring point is equipped with an independent target. The independent target should be located in the field of view of the camera of the second-level monitoring point and can be observed by the camera of the second-level monitoring point at the same time as the target of the first-level monitoring point. The three-dimensional coordinates of the target of the first-level monitoring point and the image point of the independent target of the third-level monitoring point on the camera imaging plane with known three-dimensional coordinates are obtained by using computer vision methods (that is, obtaining the three-dimensional coordinates of the target center in the three-dimensional coordinate system).

[0139] Step S202: Measure the surface displacement change of the first-level monitoring point where the Beidou satellite navigation and positioning receiver is located.

[0140] The coordinate relationship between the phase center of the antenna of the Beidou satellite navigation and positioning receiver and the target plane center is a calibrated constant value. Δp = [ΔX, ΔY, ΔZ], where Δp is the external parameter of the target plane center and the phase center of the receiver antenna in the right-handed coordinate system constructed with the target plane center as the origin, the vertical direction as the Z axis, and the front direction as the X axis. ΔX, ΔY, ΔZ are the components of the external parameters in the X, Y, and Z axis directions respectively.

[0141] By receiving the reference coordinates and differential data broadcast by the Beidou Continuously Operating Reference Station (CORS) network covering the monitoring area, and performing baseline solution, the three-dimensional coordinates of the first-level monitoring point in the CGCS2000 geodetic coordinate system with the center of mass of the earth as the origin can be obtained.

[0142] The three-dimensional coordinates obtained by the first solution are the reference coordinate values ​​p of the first-level monitoring points. r0 =[B0, L0, H0], where B0, L0, H0 are the longitude, latitude and elevation of the reference coordinates in the CGCS2000 geodetic coordinate system respectively. The three-dimensional coordinates measured for the second time are differentiated from the reference coordinates to obtain the surface displacement change ΔE of the first-level monitoring point projected in the east, north and altitude directions with the reference coordinates as the origin. 1 ,ΔN 1 ,ΔU 1 .

[0143] Step S203: measuring the surface displacement change of the second-level monitoring point where the camera is located.

[0144] The camera of the second-level monitoring point takes a picture of the target of the first-level monitoring point for the first time, and the three-dimensional coordinates of the second-level monitoring point in the CGCS2000 geodetic coordinate system are calculated as the reference coordinates of the second-level monitoring point c0 = [X O0 ,Y O0 ,Z O0 ](Please refer to the above embodiment for the solution process, which will not be repeated here); Take a second photo and solve the measured three-dimensional coordinates of the second-level monitoring point and perform the difference with the reference coordinates to obtain the surface displacement change ΔE of the second-level monitoring point projected in the east, north and height directions with the reference coordinates as the origin 2 ,ΔN 2 ,ΔU 2 .

[0145] Step S204: measuring the surface displacement change of the third-level monitoring point where the independent target is located.

[0146] The target center T of the third-level monitoring point is calculated by the two-dimensional plane coordinates of the target on the first-level monitoring point receiver and the independent target of the third-level monitoring point on the imaging plane of the camera of the second-level monitoring point and the measured target coordinates of the first-level monitoring point. i Three-dimensional coordinates in the CGCS2000 geodetic coordinate system

[0147] The three-dimensional coordinates of the independent target of the third-level monitoring point measured for the first time in the CGCS2000 geodetic coordinate system are the reference coordinates of the third-level monitoring point. The subsequent photos are taken and the measured three-dimensional coordinates are calculated and differentiated from the reference coordinates to obtain the surface displacement change ΔE of the third-level monitoring point projected in the east, north and height directions with the reference coordinates as the origin. 3 ,ΔN 3 ,ΔU 3 .

[0148] (1) This method integrates BeiDou and computer vision to solve the limitation of using only one monitoring solution in a certain monitoring project. It can calculate the surface displacement changes of multiple monitoring points, provide early warning for the occurrence of geological disasters, and avoid casualties and property losses.

[0149] (2) This method uses the targets of the three first-level monitoring points as reference targets, uses Beidou positioning technology to locate the targets, and can continuously monitor the displacement changes of the targets; by deploying cameras to shoot the three targets, the camera's posture can be determined, because the coordinates of the three targets can be continuously corrected by Beidou positioning, and thus, the camera's posture can also be corrected with each measurement. This application can correct the influence of systematic errors caused by changes in the position and posture of the camera and the target itself.

[0150] (3) In the process of locating the target at the third-level monitoring point, the three-dimensional coordinates of the target in the CGCS2000 geodetic coordinate system are located through the spatial projection principle of the camera (computer vision). This solves the problem that the surface displacement monitoring technology based on Beidou satellite positioning cannot accurately locate in scenes with weak satellite signals in existing surface displacement monitoring methods.

[0151] (4) This method can obtain the surface displacement changes of the monitoring point in the east, north and height directions.

[0152] Reference Figure 6 One embodiment of the present application provides a regional surface displacement monitoring system based on Beidou and computer vision, the system comprising:

[0153] At least three receivers are provided, each of which is installed at a different first-level monitoring point in the monitoring area, and each receiver is integrated with a first target.

[0154] At least one third target, the third target is installed at a third-level monitoring point in the monitoring area.

[0155] The camera is installed at the second-level monitoring point in the monitoring area, and the field of view of the camera covers all the first targets and the third targets.

[0156] A processor is used to obtain Beidou positioning signals received by all receivers, and calculate the first three-dimensional coordinates of each first target according to all Beidou positioning signals; and to obtain an image taken by a camera, and calculate the two-dimensional coordinates of each first target and a third target in an image coordinate system according to the image; and calculate the second three-dimensional coordinates of the camera according to all first three-dimensional coordinates and the two-dimensional coordinates of all first targets in the image coordinate system; and to calculate the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system; and to calculate the surface displacement change of all first-level monitoring points, second-level monitoring points, and third-level monitoring points according to the first three-dimensional coordinates, second three-dimensional coordinates, and third three-dimensional coordinates measured twice before and after.

[0157] It should be noted that the present system embodiment and the above method embodiment are based on the same inventive concept, and therefore the relevant contents of the above method embodiment are also applicable to the present system embodiment and will not be repeated here.

[0158] Reference Figure 7 The embodiment of the present application further provides an electronic device, the electronic device comprising:

[0159] at least one memory;

[0160] at least one processor;

[0161] at least one program;

[0162] The program is stored in the memory, and the processor executes at least one program to implement the regional surface displacement monitoring method based on Beidou and computer vision implemented in the present disclosure.

[0163] The electronic device may be any intelligent terminal including a mobile phone, a tablet computer, a personal digital assistant (PDA), a vehicle-mounted computer, etc.

[0164] Combine the following Figure 7 The electronic device according to the embodiment of the present application is introduced in detail.

[0165] like Figure 7 , Figure 7 The hardware structure of an electronic device of another embodiment is illustrated, and the electronic device includes:

[0166] The processor 1600 may be implemented by a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present disclosure;

[0167] The memory 1700 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1700 can store an operating system and other application programs. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 1700, and the processor 1600 calls and executes the regional surface displacement monitoring method based on Beidou and computer vision in the embodiment of the present disclosure.

[0168] Input / output interface 1800, used to implement information input and output;

[0169] The communication interface 1900 is used to realize the communication interaction between the device and other devices. The communication can be realized through a wired manner (such as USB, network cable, etc.) or a wireless manner (such as mobile network, WIFI, Bluetooth, etc.);

[0170] Bus 2000 , which transmits information between various components of the device (e.g., processor 1600 , memory 1700 , input / output interface 1800 , and communication interface 1900 );

[0171] The processor 1600 , the memory 1700 , the input / output interface 1800 , and the communication interface 1900 are connected to each other in communication within the device via the bus 2000 .

[0172] An embodiment of the present disclosure also provides a storage medium, which is a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the above-mentioned regional surface displacement monitoring method based on Beidou and computer vision.

[0173] The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0174] The embodiments described in the embodiments of the present disclosure are intended to more clearly illustrate the technical solutions of the embodiments of the present disclosure and do not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present disclosure are also applicable to similar technical problems.

[0175] Those skilled in the art will appreciate that the technical solutions shown in the figures do not limit the embodiments of the present disclosure and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0176] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0177] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0178] The terms "first", "second", "third", etc. in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0179] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0180] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for regional surface displacement monitoring based on Beidou and computer vision, characterized in that: The invention is applicable to surface displacement monitoring of monitoring points in a monitoring area, wherein first-level monitoring points, second-level monitoring points and third-level monitoring points are arranged in the monitoring area, the number of the first-level monitoring points is at least three and each of the first-level monitoring points is provided with a receiver integrating a first target, the third-level monitoring points are provided with a third target, the second-level monitoring points are provided with a camera and the field of view of the camera covers all the first targets and the third targets; the method comprises: Acquire the Beidou positioning signals received by all the receivers, and calculate the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals; Acquire an image captured by the camera, and calculate the two-dimensional coordinates of each of the first targets and the third target in the image coordinate system according to the image; and calculate the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system; Calculating a third three-dimensional coordinate of the third target according to the first three-dimensional coordinate of the first target, the two-dimensional coordinate of the first target in the image coordinate system, and the two-dimensional coordinate of the third target in the image coordinate system; The surface displacement changes of all the first-level monitoring points, the second-level monitoring points and the third-level monitoring points are calculated according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after.

2. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 1, characterized in that: The acquiring of all Beidou positioning signals received by the receivers, and calculating the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals, comprises: Acquire reference coordinates and differential data received by the receiver and broadcast by a Beidou continuously operating reference station network covering the monitoring area; Performing baseline solution according to the reference coordinates and the differential data to obtain the three-dimensional coordinates of the antenna of the receiver; According to the coordinate relationship between the antenna of each receiver and the corresponding first target, the first three-dimensional coordinates of each first target in the CGCS2000 geodetic coordinate system are calculated respectively.

3. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 2 is characterized in that: The step of calculating the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system comprises: establishing an image coordinate system according to the image; According to each imaging point of the first target and the third target on the image, the two-dimensional coordinates of each of the first target and the third target on the image coordinate system are calculated.

4. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 3 is characterized in that: The number of the first-level monitoring points is three.

5. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 4 is characterized in that: The step of calculating the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system comprises: Let the second three-dimensional coordinate of the camera in the CGCS2000 geodetic coordinate system be c=[X O ,Y O ,Z O ]; let the first three-dimensional coordinate of the first target be [X A ,Y A ,Z A ], the first three-dimensional coordinate of the second first target is [X B ,Y B ,Z B ], the first three-dimensional coordinate of the third first target is [X C ,Y C ,Z C ]; According to [X A ,Y A ,Z A ],[X B ,Y B ,Z B ],[X C ,Y C ,Z C ], we can calculate: in, Indicates [X A ,Y A ,Z A ] and [X B ,Y B ,Z B ] is the square of the straight-line distance between them; Indicates [X B ,Y B ,Z B ] and [X C ,Y C ,Z C ] is the square of the straight-line distance between them; Indicates [X C ,Y C ,Z C ] and [X A ,Y A ,Z A ] is the square of the straight-line distance between A Indicates [X A ,Y A ,Z A ] and [X O ,Y O ,Z O ]; x B Indicates [X B ,Y B ,Z B ] and [X O ,Y O ,Z O ]; x C Indicates [X C ,Y C ,Z C ] and [X O ,Y O ,Z O ]; cosθ AB Indicates angle θ AB The cosine value of BC Indicates angle θ BC The cosine value of CA Indicates angle θ CA The cosine of the angle θ AB Indicates [X A ,Y A ,Z A ]、[X B ,Y B ,Z B ] respectively with [X O ,Y O ,Z O ]; angle θ BC Indicates [X B ,Y B ,Z B ]、[X C ,Y C ,Z C ] respectively with [X O ,Y O ,Z O ]; angle θ CA Indicates [X C ,Y C ,Z C ]、[X A ,Y A ,Z A ] respectively with [X O ,Y O ,Z O ]The angle between the connecting lines; Solve according to Wu's elimination method The following system of equations is obtained: Among them, a i is a polynomial f(x A ), b i is a polynomial f(x B ), c i is a polynomial f(x C ) coefficient; Solving the system of equations, we get c = [X O ,Y O ,Z O ]’s value.

6. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 5 is characterized in that: The calculating the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system comprises: Let the third three-dimensional coordinate of the third target in the CGCS2000 geodetic coordinate system be And according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system, the following three formulas are constructed: Among them, T i represents a target center of the third target; express With [X O ,Y O ,Z O ] the straight-line distance between Indicates [X A ,Y A ,Z A ]、 Respectively with [X O ,Y O ,Z O ]The angle between the lines; angle Indicates [X B ,Y B ,Z B ]、 With [X O ,Y O ,Z O ] respectively connected by the angle; angle Indicates [X C ,Y C ,Z C ]、 Respectively with [X O ,Y O ,Z O ]The angle between the connecting lines; Solving the above three formulas, we get The value of .

7. The method for regional surface displacement monitoring based on Beidou and computer vision according to claim 6 is characterized in that: The calculating of the surface displacement changes of all the first-level monitoring points, the second-level monitoring points and the third-level monitoring points according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after includes: The first three-dimensional coordinates of the latter measurement are differentiated from the first three-dimensional coordinates of the previous measurement to obtain the surface displacement change in the east, north and altitude directions projected with the first three-dimensional coordinates of the first-level monitoring point of the previous measurement as the origin; The second three-dimensional coordinates of the latter measurement are differentiated from the second three-dimensional coordinates of the previous measurement to obtain the surface displacement change in the east, north and altitude directions projected with the first three-dimensional coordinates of the second-level monitoring point of the previous measurement as the origin; The third three-dimensional coordinates of the latter measurement are differentiated from the third three-dimensional coordinates of the previous measurement to obtain the surface displacement change projected in the east, north and height directions with the first three-dimensional coordinates of the third-level monitoring point of the previous measurement as the origin.

8. A regional surface displacement monitoring system based on Beidou and computer vision, characterized in that: The system comprises: At least three receivers, each of which is installed at a different first-level monitoring point in the monitoring area, and each of which is integrated with a first target; at least one third target, the third target being installed at a third-level monitoring point within the monitoring area; A camera is installed at a second-level monitoring point in the monitoring area, and the field of view of the camera covers all of the first targets and the third targets; A processor is used to obtain Beidou positioning signals received by all the receivers, and calculate the first three-dimensional coordinates of each of the first targets according to all the Beidou positioning signals; and to obtain the image taken by the camera, and calculate the two-dimensional coordinates of each of the first targets and the third target in the image coordinate system according to the image; and calculate the second three-dimensional coordinates of the camera according to all the first three-dimensional coordinates and the two-dimensional coordinates of all the first targets in the image coordinate system; and to calculate the third three-dimensional coordinates of the third target according to the first three-dimensional coordinates of the first target, the two-dimensional coordinates of the first target in the image coordinate system, and the two-dimensional coordinates of the third target in the image coordinate system; and to calculate the surface displacement change of all the first-level monitoring points, the second-level monitoring points and the third-level monitoring points according to the first three-dimensional coordinates, the second three-dimensional coordinates and the third three-dimensional coordinates measured twice before and after.

9. An electronic device, characterized in that: include: at least one memory; at least one processor; at least one computer program; The computer program is stored in the memory, and the processor executes at least one computer program to implement: the regional surface displacement monitoring method based on Beidou and computer vision as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Computer executable instructions are stored, and the computer executable instructions are used to execute the regional surface displacement monitoring method based on Beidou and computer vision as described in any one of claims 1 to 7.

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