Carrier position determination method and device, computer equipment and storage medium

Abstract

The invention relates to the technical field of visual inertia fusion positioning, and discloses a carrier position determination method and device, computer equipment and a storage medium. The method comprises the following steps: acquiring one-dimensional distance information, pixel coordinates of a laser measurement point in an image and a state vector of a carrier at the current moment; taking the pixel coordinates of the laser measurement points in the image as new feature points for tracking, and performing triangularization on the new feature points and other successfully tracked image feature points to obtain three-dimensional coordinates of the laser measurement points and other image feature points; detecting whether the laser measurement point meets a coplanarity condition or not, and solving an equation and a unit normal vector of a fitting plane; determining a scale zooming coefficient based on the normal vector of the plane, the laser direction unit vector, the one-dimensional distance information and the position of the laser measurement point; and adjusting the state vector of the carrier at the current moment based on the scale scaling coefficient, and determining the position of the carrier.

Description

Technical Field

[0001] The present invention relates to the field of visual-inertial fusion positioning technology, and in particular to a method, device, computer equipment and storage medium for determining a carrier position. Background Art

[0002] GPS positioning technology performs well in open environments, but its positioning performance significantly decreases in urban canyons, indoor environments, or when GPS signals are limited. Therefore, Visual Inertial Odometry (VIO) technology based on the fusion of vision and inertial sensors has gradually become a research hotspot, providing a new solution for precise positioning in complex environments.

[0003] As an important form of visual-inertial fusion technology, monocular visual-inertial odometry (Monocular VIO) integrates a single camera with a low-cost micro-electromechanical system inertial measurement unit to achieve continuous high-precision positioning in the absence of an external absolute position reference.

[0004] Monocular visual inertial odometry cannot directly observe the absolute scale of the real world, and can only estimate the scale factor through the relative changes of visual and inertial information. In theoretical analysis, when the carrier is in zero acceleration or constant acceleration motion (such as stationary hovering, uniform linear motion), the scale factor will no longer be in the right null space of the observability matrix, resulting in the system being unable to accurately observe and maintain scale information, which in turn causes scale drift and seriously affects positioning accuracy. Summary of the invention

[0005] In view of this, the present invention provides a method, apparatus, computer device and storage medium for determining the position of a carrier to solve the problem that the scale information cannot be accurately observed and maintained, thereby causing scale drift and seriously affecting the positioning accuracy.

[0006] In a first aspect, the present invention provides a method for determining a carrier position, the method comprising: obtaining one-dimensional distance information, pixel coordinates of a laser measurement point in an image, and a state vector of the carrier at a current moment; wherein the state vector of the carrier at a current moment related to the scale comprises: the position of an image feature point, the historical carrier position in a sliding window at a current moment, and the carrier speed at a current moment; tracking the pixel corresponding to the laser measurement point in the image as a new feature point, and triangulating it together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement point and other image feature points; triangulating the successfully triangulated laser measurement point and the successfully triangulated image feature points within a preset range on a camera normalized plane; based on the three-dimensional coordinates of the laser measurement point and the image feature point, detecting whether the coplanarity condition is met at the laser measurement point, and obtaining the equation and unit normal vector of the fitted plane; determining the scale scaling factor based on the plane normal vector, the laser direction unit vector, the one-dimensional distance information, and the position of the triangulated laser measurement point; adjusting the state vector of the carrier at a current moment based on the scale scaling factor to determine the carrier position.

[0007] The method for determining the position of the carrier provided in this embodiment can determine the coordinates of the laser measurement point and the image feature point in three-dimensional space by triangulating the laser measurement point and other image feature points, thereby detecting the coplanarity at the laser measurement point. In addition, by determining the normal vector of the fitting plane, the laser direction unit vector, the laser ranging result, and the position of the laser point after triangulation, and then determining the scale scaling coefficient, the state vector of the carrier at the current moment can be effectively adjusted to reduce scale drift and improve scale stability. In addition, by using coplanarity detection, the measurement result jump at the laser measurement point is avoided, the robustness of the entire system is improved, and the positioning accuracy of the carrier is improved.

[0008] In an optional embodiment, the step of determining the pixel coordinates of the laser measurement point in the image includes: obtaining a single-point laser ranging result and external parameter information of the laser measurement device relative to the shooting device in the coordinate system of the shooting device; wherein the laser measurement device is used to measure one-dimensional distance information, and the shooting device is used to shoot images, and the external parameter information includes: a direction unit vector of the laser in the coordinate system of the shooting device and a position of the laser measurement device in the coordinate system of the shooting device; determining the position of the laser measurement point in the coordinate system of the shooting device based on the single-point laser ranging result, the position of the laser measurement device in the coordinate system of the shooting device and the laser direction unit vector in the coordinate system of the shooting device; normalizing the position of the laser measurement point in the coordinate system of the shooting device, and determining the pixel coordinates of the laser measurement point in the image based on the internal parameter information.

[0009] The method for determining the carrier position provided in this embodiment can accurately calculate the position of the laser measurement point in the captured image by obtaining the single-point laser ranging result and the external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device (including the direction unit vector of the laser and the position of the laser measuring device in the coordinate system of the shooting device).

[0010] In an optional embodiment, the step of determining the three-dimensional coordinates of the laser measurement point includes: tracking the pixels corresponding to the laser measurement point using the optical flow method, and after the number of continuous tracking times meets the preset number, triangulating the laser measurement point to obtain the three-dimensional coordinates of the laser measurement point.

[0011] The method for determining the position of the carrier provided in this embodiment tracks the laser measurement point by the optical flow method, and can track the laser measurement point even if the pixel point corresponding to the laser measurement point is not detected as a key point by the image detection algorithm; continuous multi-frame tracking ensures the stability of the tracking result and prevents tracking failure.

[0012] In an optional embodiment, based on the three-dimensional coordinates of the laser measurement point and the image feature point, it is detected whether the coplanarity condition is met at the laser measurement point, and the equation and unit normal vector of the fitting plane are obtained, including: projecting the laser measurement point and the image feature point onto the normalized plane of the shooting device for Delaunay triangulation, and corresponding the triangulation result to the triangular facets in the three-dimensional space; respectively determining the space normal vector corresponding to each triangular facet; based on the space normal vector, determining the angle between adjacent triangular facets with the laser measurement point as the vertex; detecting whether the angle between adjacent triangular facets is not greater than a preset angle threshold, if the angle between adjacent triangular facets is not greater than the preset angle threshold, then the vertices on the adjacent triangular facets are approximately coplanar, indicating that the coplanarity condition is met at the laser measurement point; if the coplanarity condition is met at the laser measurement point, the plane equation is obtained by fitting the vertices on the adjacent triangular facets according to the least squares method, and the unit normal vector of the plane is obtained at the same time; if the coplanarity condition is not met, no subsequent calculation is performed, and the coplanarity test is performed again after waiting for the measurement result at the next moment.

[0013] The method for determining the position of the carrier provided in this embodiment can effectively connect the laser measurement points and the image feature points into continuous triangular facets in three-dimensional space through triangulation, so as to facilitate coplanarity detection through the angles of their normal vectors. By calculating the angles between adjacent triangular facets and judging whether they are approximately coplanar, some non-critical or noisy points can be excluded, avoiding measurement result jumps at the laser measurement points, and improving the robustness of the system.

[0014] In a second aspect, the present invention provides a device for determining a carrier position, the device comprising: a first acquisition module, used to acquire one-dimensional distance information, pixel coordinates of a laser measurement point in an image, and a state vector of the carrier at a current moment; wherein the state vector of the carrier at a current moment related to the scale comprises: the position of an image feature point, the historical carrier position in a sliding window at a current moment, and the carrier speed at a current moment; a first processing module, used to track the pixel coordinates of the laser measurement point in the image as a new feature point, and triangulate it together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement point and other image feature points; a detection module, used to detect whether a triangular facet within a preset range of the laser measurement point satisfies a coplanarity condition, and to obtain a plane equation and a corresponding unit normal vector; a first determination module, used to determine a scale scaling factor based on the plane's normal vector, the laser direction unit vector, the one-dimensional distance information, and the triangulated laser point position; a second determination module, used to adjust the state vector of the carrier at a current moment based on the scale scaling factor to determine the carrier position.

[0015] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the method for determining the carrier position of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0016] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for determining a carrier position of the first aspect or any corresponding embodiment thereof.

[0017] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the method for determining a carrier position of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a schematic diagram of a process for determining a carrier position according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of a process for determining a position of another carrier according to an embodiment of the present invention;

[0021] Figure 3 is a structural block diagram of a device for determining a carrier position according to an embodiment of the present invention;

[0022] Figure 4 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] Based on relevant technologies, it is known that GPS positioning technology performs well in open environments, but its positioning performance significantly decreases in urban canyons, indoor environments, or when GPS signals are limited. Therefore, Visual Inertial Odometry (VIO) technology based on the fusion of vision and inertial sensors has gradually become a research hotspot, providing a new solution for precise positioning in complex environments.

[0025] As an important form of visual-inertial fusion technology, monocular visual-inertial odometry (Monocular VIO) integrates a single camera with a low-cost micro-electromechanical system inertial measurement unit to achieve continuous high-precision positioning in the absence of an external absolute position reference.

[0026] Monocular visual inertial odometry cannot directly observe the absolute scale of the real world, and can only estimate the scale factor through the relative changes of visual and inertial information. In theoretical analysis, when the carrier is in zero acceleration or constant acceleration motion (such as stationary hovering, uniform linear motion), the scale factor will no longer be in the right null space of the observability matrix, resulting in the system being unable to accurately observe and maintain scale information, which in turn causes scale drift and seriously affects positioning accuracy.

[0027] Based on this, the present invention provides a method for determining the position of a carrier. By triangulating the laser measurement point and other image feature points, the coordinates of the laser measurement point and the image feature point in three-dimensional space can be determined, thereby detecting the coplanarity at the laser measurement point. In addition, by determining the normal vector of the fitting plane, the laser direction unit vector, the laser ranging result, and the position of the laser point after triangulation, and then determining the scale scaling coefficient, the state vector of the carrier at the current moment can be effectively adjusted to reduce scale drift and improve scale stability. In addition, by using coplanarity detection, the measurement result jump at the laser measurement point can be avoided, the robustness of the entire system can be improved, and the positioning accuracy of the carrier can be improved.

[0028] According to an embodiment of the present invention, an embodiment of a method for determining a carrier position is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0029] In this embodiment, a method for determining the position of a carrier is provided, which can be used in computer devices, such as computers, servers, etc. Figure 1 is a flow chart of a method for determining a carrier position according to an embodiment of the present invention, such as Figure 1 As shown, the process includes the following steps:

[0030] Step S101, obtain one-dimensional distance information, the pixel coordinates of the laser measurement point in the image and the current state vector of the carrier; wherein the current state vector of the carrier related to the scale includes: the position of the image feature point, the historical carrier position in the sliding window at the current moment and the current carrier speed.

[0031] One-dimensional distance information may be distance information measured by single-point laser ranging. The carrier may be a vehicle, an unmanned aerial vehicle, etc., which is not specifically limited here. Pixel coordinates may be used to characterize the position identification of pixel points on an image, and may be composed of horizontal and vertical coordinates. Feature points may be used to characterize points of specific unique properties, and are used for image matching and tracking, etc. Specifically, feature points may be selected by extracting key points in an image (such as FAST corner points) and calculating descriptors of key points (such as BRIEF descriptors), and tracking may be performed by matching feature points with the same features from images of two adjacent frames. The current state vector of the carrier is a set of parameters that may be used to characterize the motion state of the carrier, including but not limited to position, velocity, acceleration, attitude, etc., which is not specifically limited here, and may be implemented by those skilled in the art.

[0032] Preferably, the state vector of the carrier at the current moment may include: the historical carrier position in the current moment sliding window, the carrier velocity at the current moment, the historical carrier attitude in the current moment sliding window, the carrier angular velocity at the current moment, the zero bias of the inertial device at the current moment, and the gravity direction.

[0033] Specifically, the position coordinates of the laser point on the image that can be captured by an image sensor (such as a CCD or CMOS camera) are usually in pixels. Points with significant features (such as corner points, edge points) that can be pre-defined or identified in the image, these points usually correspond to fixed or identifiable parts on the object in the actual scene, etc., are not specifically limited here, and can be implemented by those skilled in the art. For example: a drone is flying, and a laser rangefinder is installed underneath it. The laser rangefinder emits a laser beam and captures the reflected laser point. The position of this point on the image captured by the drone camera is the pixel coordinate of the laser point. At the same time, the monocular visual inertial odometer on the drone provides its current position, speed and other state information, which constitutes the current state vector of the carrier.

[0034] Step S102 : Track the pixel corresponding to the laser measurement point in the image as a new feature point, and triangulate it together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement point and other image feature points.

[0035] Other successfully tracked image feature points may be feature points that match in two frames of images. Triangulation may be to calculate the coordinates of these points in three-dimensional space using the principle of multi-view geometry through pixel coordinates (or feature point positions) under two or more view angles and internal and external parameters of the camera.

[0036] Specifically, the three-dimensional coordinates can be calculated by using images taken at two different viewing angles after displacement by a monocular vision system, or by using a binocular vision system and the parallax information of two cameras, etc., which are not specifically limited here and can be implemented by those skilled in the art. For example: in a monocular vision system, the pixel coordinates of matching points in two images taken by a camera at different times and at different positions can be used to calculate the coordinates of the point in three-dimensional space in combination with the internal and external parameters of the camera.

[0037] Step S103, based on the three-dimensional coordinates of the laser measurement point and the image feature point, detect whether the coplanarity condition is met at the laser measurement point, and obtain the equation and unit normal vector of the fitting plane.

[0038] The coplanarity detection is used to evaluate whether the laser measurement point and the image feature points within a preset range are approximately in the same plane. Specifically, the coplanarity detection can be performed by triangulation + angle detection.

[0039] Triangulation can be the process of connecting a set of points on a plane or a curved surface into a set of non-overlapping triangles. Specifically, a set of points and their normalized plane coordinates are used as input, and these points are connected into triangular facets using a triangulation algorithm (such as Delaunay triangulation, Marching Cubes, etc.) to cover the entire shape in three-dimensional space. Specifically, the triangulation function in an open source library such as CGAL (Computational Geometry Algorithms Library) can be used, which is not specifically limited here and can be implemented by those skilled in the art. For example: a set of feature points, through triangulation, these points are connected into multiple triangles to form a continuous three-dimensional mesh.

[0040] Angle detection is to determine the size of the spatial angle between each adjacent triangular face after triangulation. Specifically, the spatial normal vector of each triangular face can be calculated, and then the angle between adjacent triangular facets can be detected to see if it is not greater than the preset angle threshold. If the angle between adjacent triangular facets is not greater than the preset angle threshold, then the vertices on the adjacent triangular facets are approximately coplanar, satisfying the coplanarity condition.

[0041] Specifically, the least square method can be used to fit the plane equation to obtain the normal vector of the plane. The covariance matrix of the three-dimensional coordinates of the laser measurement point and the image feature point can also be directly calculated, and the eigenvector corresponding to the minimum eigenvalue in its eigenvector is obtained as the normal vector of the plane, etc., which is not specifically limited here and can be implemented by those skilled in the art. For example: a plane equation Ax+By+Cz+D=0 is fitted by the least square method, then the vector (A, B, C) is the normal vector of the plane.

[0042] Step S104, determining a scale scaling factor based on the plane normal vector, the laser direction unit vector, the one-dimensional distance information, and the position of the triangulated laser measurement point.

[0043] The scaling factor is a factor that can be used to adjust or calibrate the scale error in the measurement data. In visual navigation and positioning systems, due to factors such as sensor characteristics and environmental interference, the measured distance, size and other information may have a certain scale error, which needs to be corrected by the scaling factor.

[0044] Through geometric and physical relationships, a scale scaling factor is determined using known information (normal vector of the plane, unit vector of the laser direction, one-dimensional distance information, and the position of the laser measurement point after triangulation). This scale scaling factor can be used to adjust or calibrate the scale error in the carrier position estimation, especially in monocular vision or laser ranging-based systems. Due to the incompleteness of depth information, scale information often needs to be indirectly obtained by other means. Specifically, a geometric model can be constructed using the plane geometry principle through the normal vector of the plane, the direction vector of the laser beam, and the position information of the intersection of the laser beam and the plane. By analyzing the geometric equation, the actual length of the laser ranging point from the origin (optical center) of the coordinate system of the shooting device in the real world is solved, and compared with the "apparent distance" obtained by triangulation, so as to calculate the scale scaling factor. It is also possible to use machine learning algorithms (such as neural networks, support vector machines, etc.) based on a large amount of training data to learn the mapping relationship from image features (including laser point positions, feature point positions, etc.) to scale scaling factors, etc., which are not specifically limited here and can be implemented by those skilled in the art.

[0045] For example, there is a drone equipped with a laser rangefinder and a camera. The drone measures the distance to a ground marker through the laser rangefinder, and calculates the position of the laser point in the image taken by the camera through external parameters and other information. At the same time, the drone also obtains its approximate position and attitude information through other means (such as IMU, GPS, etc.). At this time, the one-dimensional ranging information, the unit vector of the direction of the laser beam, and the external parameters of the laser rangefinder relative to the camera can be used to calculate the true length of the laser ranging point from the optical center of the camera through geometric analysis, and compared with the "apparent length" obtained by triangulation to obtain the scale scaling coefficient. Then, use this coefficient to adjust the position estimate of the drone to improve the accuracy of positioning.

[0046] Step S105: adjusting the current state vector of the carrier based on the scale scaling factor to determine the position of the carrier.

[0047] After obtaining the scale scaling coefficient, it is applied to the scale-related state of the carrier at the current moment, and the scale-related state in the state vector is scaled and adjusted to eliminate or reduce the scale error. The adjusted state vector more accurately reflects the position of the carrier in the real world. Specifically, the scale scaling coefficient can be directly applied to the position of the image feature points in the state vector, the historical carrier position in the sliding window at the current moment, and the carrier speed at the current moment, and these states can be scaled proportionally. It can also be filtered according to other measured states (such as the angle between the laser emission direction and the plane at the laser measurement point), etc., which is not specifically limited here and can be implemented by those skilled in the art.

[0048] For example, after obtaining the scale scaling factor, the drone applies it to the image feature point position in the self-position estimation, the historical self-position in the current sliding window, and the current self-speed, and scales these states in equal proportion. Assuming the scale scaling factor is 1.05 (indicating that the actual distance is 5% greater than the measured distance), the drone multiplies each value in the image feature point position, the historical self-position in the current sliding window, and the current self-speed by 1.05 to obtain a state closer to the actual state. The adjusted position and other states will be used in subsequent navigation, obstacle avoidance and other tasks.

[0049] The method for determining the position of the carrier provided in this embodiment can determine the coordinates of the laser measurement point and the image feature point in three-dimensional space by triangulating the laser measurement point and other image feature points, thereby detecting the coplanarity at the laser measurement point. In addition, by determining the normal vector of the fitting plane, the laser direction unit vector, the laser ranging result, and the position of the laser point after triangulation, and then determining the scale scaling coefficient, the state vector of the carrier at the current moment can be effectively adjusted to reduce scale drift and improve scale stability. In addition, by using coplanarity detection, the measurement result jump at the laser measurement point is avoided, the robustness of the entire system is improved, and the positioning accuracy of the carrier is improved.

[0050] In an optional embodiment, the step of determining the pixel coordinates of the laser point in the image includes:

[0051] Step a1, obtaining the single-point laser ranging result and the external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device; wherein the laser measuring device is used to measure one-dimensional distance information, the shooting device is used to shoot images, and the external parameter information includes: the direction unit vector of the laser in the coordinate system of the shooting device and the position of the laser measuring device in the coordinate system of the shooting device.

[0052] The shooting device can be used to characterize the device for capturing images. Among them, the shooting device can include a camera, etc., which is not specifically limited here. The laser measuring device can be a device that can emit laser and measure the distance between the laser and the object. Among them, the laser measuring device can be a single-point laser rangefinder, and can also be other devices that can emit laser and measure the distance between the laser and the object, etc., which is not specifically limited here, and the type of laser measuring device can be specifically set according to needs. The single-point laser ranging result can be the distance measured by the laser measuring device. External parameter information can be used to characterize the parameters of the conversion relationship between two different coordinate systems. Among them, the external parameter information can include: the direction unit vector of the laser in the camera coordinate system and the position of the laser emitter in the camera coordinate system. Direction unit vector: obtained through the calibration process, during which the angle between the emission direction of the laser measuring device and the three axes of the shooting device coordinate system will be determined, and then the direction unit vector will be calculated. Position vector: also obtained through calibration, the calibration process will determine the three-dimensional coordinates of the origin of the laser measuring device in the shooting device coordinate system.

[0053] Specifically, the built-in sensor or algorithm of the laser measuring device can be used to directly output the three-dimensional coordinates of the laser point in the coordinate system of the shooting device; if the laser measuring device does not directly output the three-dimensional coordinates, it may be necessary to use image processing technology (such as edge detection, threshold segmentation, etc.) to identify the laser spot and estimate its position in the image, and then combine the camera's intrinsic parameter matrix to infer the three-dimensional coordinates, etc., which is not specifically limited here and can be implemented by technical personnel in this field.

[0054] For example, the shooting device is a camera, and the laser measuring device is a single-point laser rangefinder. Through calibration, it can be known that the unit vector of the laser rangefinder's emission direction in the shooting device coordinate system is (0, 0, 1), indicating that the laser is emitted in the positive direction of the Z axis; at the same time, the position vector of the origin of the single-point laser rangefinder in the shooting device coordinate system is (0.5, 0, 0.2), indicating that the laser rangefinder is located 0.5 meters in front of the camera, with a horizontal offset of 0 meters and a vertical offset of 0.2 meters.

[0055] Step a2, determining the position of the laser measurement point in the coordinate system of the shooting device based on the single-point laser ranging result, the position of the laser measurement device in the coordinate system of the shooting device and the laser direction unit vector in the coordinate system of the shooting device.

[0056] Specifically, when the position of the laser range image meets the preset conditions, the precise position of the laser point in the coordinate system of the shooting device (camera) is calculated through geometric transformation using the position and external parameter information obtained in step a1.

[0057] If the laser measuring device outputs the distance between the laser measuring point and its measuring origin, it is necessary to use the external parameter information (direction unit vector and position vector) to perform coordinate transformation and convert the laser point coordinates to the coordinate system of the shooting device. For example: the laser rangefinder outputs the distance L between the laser measuring point and its measuring origin. Since the position (x, y, z) and direction (ex, ey, ez) of the laser rangefinder in the shooting device coordinate system are known, the coordinates of the laser measuring point in the shooting device coordinate system can be obtained by analytical geometry calculation as (x+L*ex, y+L*ey, z+L*ez).

[0058] Step a3, normalizing the position of the laser measurement point in the coordinate system of the shooting device, and determining the pixel coordinates of the laser measurement point in the image according to the internal reference information.

[0059] Convert the three-dimensional coordinates of the laser point in the shooting device (camera) coordinate system into two-dimensional pixel coordinates on the image plane. Specifically, the three-dimensional coordinates of the laser point in the camera coordinate system can be projected onto the normalized image plane through the intrinsic parameter matrix. Considering the distortion of the camera (such as radial distortion and tangential distortion), the normalized coordinates are corrected for distortion. Convert the corrected normalized coordinates into pixel coordinates. For example: the intrinsic parameter matrix of the camera is known, and the normalized coordinates have been corrected for distortion. Through the intrinsic parameter matrix and the distortion correction model, we can convert the three-dimensional coordinates (Xc, Yc, Zc) of the laser point in the camera coordinate system into two-dimensional pixel coordinates (u, v) on the image plane.

[0060] The method for determining the carrier position provided in this embodiment can accurately calculate the position of the laser measurement point in the captured image by obtaining the single-point laser ranging result and the external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device (including the direction unit vector of the laser and the position of the laser measuring device in the coordinate system of the shooting device).

[0061] In an optional implementation, the above step 104 includes:

[0062] Step b1, projecting the laser measurement points and the image feature points onto the normalized plane of the shooting device for Delaunay triangulation, and corresponding the triangulation results to triangular facets in the three-dimensional space.

[0063] Triangulation can be the process of connecting a set of points on a plane or a curved surface into a set of non-overlapping triangles. Specifically, a set of points and their normalized plane coordinates are used as input, and these points are connected into triangular facets using a triangulation algorithm (such as Delaunay triangulation, Marching Cubes, etc.) to cover the entire shape in three-dimensional space. Specifically, the triangulation function in an open source library such as CGAL (Computational Geometry Algorithms Library) can be used, which is not specifically limited here and can be implemented by those skilled in the art. For example: a set of feature points, through triangulation, these points are connected into multiple triangles to form a continuous three-dimensional mesh.

[0064] Step b2, respectively determine the space normal vector corresponding to each triangular facet.

[0065] For each triangle, calculate its normal vector. The normal vector is a vector perpendicular to the plane of the triangle, which is used to indicate the orientation of the facet. Specifically, the three vertex coordinates of the triangle are used to calculate the normal vector by vector cross product, etc., which is not specifically limited here and can be implemented by those skilled in the art. For example: the three vertex coordinates of a triangle are A (x1, y1, z1), B (x2, y2, z2), and C (x3, y3, z3), then the unit normal vector N = (AB×AC) / |AB×AC|, where × represents the vector cross product.

[0066] Step b3, based on the space normal vector, determine the angle between adjacent triangular facets with the laser measurement point as the vertex.

[0067] The relative position relationship between the facets is determined by calculating the angle between the normal vectors of adjacent triangle facets. Specifically, the vector dot product formula can be used to calculate the cosine value of the angle between the two normal vectors, and then the angle is obtained by the inverse cosine function. No specific limitation is made here, and it can be implemented by those skilled in the art. For example: two normal vectors N1 and N2, the angle between them θ = arccos(N1·N2 / (|N1|*|N2|), where · represents the vector dot product.

[0068] Step b4, detecting whether the angle between adjacent triangular facets is not greater than a preset angle threshold. If the angle between adjacent triangular facets is not greater than the preset angle threshold, the vertices on the adjacent triangular facets are approximately coplanar, indicating that the coplanarity condition is met at the laser measurement point.

[0069] The preset angle threshold can be used to characterize the angle that can characterize the triangles being in the same plane. The preset angle can be 5° or 10°, etc., which is not specifically limited here.

[0070] Step b5: If the coplanarity condition is met at the laser measurement point, the plane equation is obtained by fitting the vertices on the adjacent triangular facets using the least squares method, and the unit normal vector of the plane is obtained at the same time.

[0071] Step b6: If the coplanarity condition is not met, no subsequent calculation is performed, and the coplanarity test is performed again after waiting for the measurement result at the next moment.

[0072] If it is detected that the laser measurement point and the existing vertex do not meet the coplanarity condition, the current loop is terminated directly or the subsequent calculation steps are skipped, and the coplanarity test is performed again after the measurement result at the next moment. This usually involves a simple conditional judgment and logic flow control.

[0073] The method for determining the position of the carrier provided in this embodiment can effectively connect the laser measurement points and the image feature points into continuous triangular facets in three-dimensional space through triangulation, so as to facilitate coplanarity detection through the angles of their normal vectors. By calculating the angles between adjacent triangular facets and judging whether they are approximately coplanar, some non-critical or noisy points can be excluded, avoiding measurement result jumps at the laser measurement points, and improving the robustness of the system.

[0074] In an optional embodiment, the step of tracking the image feature points includes: tracking the pixels corresponding to the laser measurement points by optical flow method, and after the number of continuous tracking times meets the preset number, triangulating the laser measurement points to obtain the three-dimensional coordinates of the laser measurement points.

[0075] The preset number can represent the number of times the pixel corresponding to the laser measurement point is correctly tracked (such as 5 times, 10 times, etc.). Specifically, the optical flow method is used to track the motion trajectory of specific pixel coordinates in continuous image frames. The optical flow method estimates the motion of pixels or feature points by analyzing the temporal changes in pixel intensity or color in the image sequence and the spatial correlation between adjacent frames. For example: using the Lucas-Kanade algorithm to track a pixel coordinate, the algorithm analyzes the grayscale changes of the pixel and its neighborhood in continuous frames to estimate the direction and speed of the pixel's motion.

[0076] The method for determining the position of the carrier provided in this embodiment tracks the laser measurement point by the optical flow method, and can track the laser measurement point even if the pixel point corresponding to the laser measurement point is not detected as a key point by the image detection algorithm; continuous multi-frame tracking ensures the stability of the tracking result and prevents tracking failure.

[0077] Combination Figure 2 As shown, in an optional implementation manner, this embodiment provides a method for determining a carrier position, the method comprising the following steps:

[0078] Step 1: Use the visual inertial odometry to recursively obtain the current state vector.

[0079] Among them, p k-c ,…,p k is the historical carrier position in the sliding window at the current moment, v k is the carrier speed at the current moment, R k-c ,…,R k is the historical carrier posture in the sliding window at the current moment, ω k is the carrier angular velocity at the current moment, b k is the zero bias of the inertial device at the current moment, To track the position of the successful feature point, R g is the direction of gravity, and kc is a period of time before the current moment. Among them, the current state vector of the carrier related to scale update is:

[0080] Step 2: Calculate the position of the intersection of the laser beam and the scene (laser measurement point) in the image based on the external parameters of the single-point laser rangefinder relative to the camera and the ranging results. The external parameters of the single-point laser rangefinder relative to the camera include the unit vector of the laser direction in the camera coordinate system. C n R The position of the laser emitter relative to the camera coordinate system C p R0 When the single-point laser measurement result is r mk When , the position of the laser point in the camera can be expressed as: C p R =r mk C n R + C p R0 .

[0081] The coordinates of the laser measurement point on the normalized plane of the camera can be determined by the following formula: R =Λ( C p R ), where u R is the coordinate of the laser measurement point on the normalized plane of the camera. The function Λ(·) can be: Λ([x,y,z] T )=[x / z,y / z] T ; Where x is the x-axis coordinate, y is the y-axis coordinate, and z is the z-axis coordinate.

[0082] Then, the pixel coordinates of the laser measurement point in the image can be obtained (u r ,v r ), where u r is the horizontal axis, v r Is the vertical axis.

[0083] Step 3: Track the pixels corresponding to the laser measurement point using the optical flow method. After the number of continuous successful tracking frames exceeds the threshold, triangulate the point to obtain the three-dimensional coordinates of the laser measurement point. At the same time, track and triangulate other image feature points.

[0084] Step 4: Perform Delaunay triangulation on the normalized plane with the triangulated laser measurement points and other image feature points, and correspond the triangulation results to triangular patches in three-dimensional space, and calculate the spatial normal vector of each triangular patch: n j =(p j1 -p j2 )×(p j3 -p j2 ), where n j is the space normal vector, p ji Represents the coordinates of the i-th vertex of the j-th triangle in space.

[0085] Step 5: Starting from the triangle containing the laser measurement point, calculate the angle between the normals of the triangle with adjacent edges: θ ij =arccos(n i ·n j ), where θ ij is the angle between the normals of the triangles on adjacent edges, n i and n j Refers to the unit normal vectors of these two triangles.

[0086] If the included angle is less than a given threshold ∈, it indicates that the vertices of the current two triangles are approximately coplanar. If the included angles between adjacent triangles are not greater than the preset angle threshold ∈, then the vertices on the adjacent triangles are approximately coplanar, indicating that the coplanarity condition is met at the laser measurement point.

[0087] If the coplanarity condition is met at the laser measurement point, for all approximately coplanar vertices, the random sampling consensus (RANSAC) method based on the distance from the point to the plane is used to eliminate the outliers and calculate the plane equation, and determine all the coplanar feature points. The plane parameters are the coordinates of the nearest point from the origin to the plane Π k The distance d from the origin to the plane is k and the plane normal vector n k It can be expressed as: k =||Π k ||;n k =Π k / d k .

[0088] If the coplanarity condition is not met, no subsequent calculation is performed, and the coplanarity test is performed again after waiting for the measurement result at the next moment.

[0089] Step 6: After the processing in step 5, the laser measurement point meets the coplanarity condition, and the single-point laser distance measurement value r at this time is considered mk is valid data, from which the scale scaling factor with filtering can be calculated:

[0090] Where i∈[kc,k], and i is the moment when the laser point is successfully tracked, r mi The position of the laser distance image at the moment when the laser point tracking is successful.

[0091] Step 7: Use the scale scaling factor to update the current state vector of all carriers related to the scale update:

[0092] Where η is the scale scaling factor, The current state vector of the relevant carrier is updated for the updated scale. The current state vector of the relevant carrier is updated according to the updated scale to determine the final position of the carrier.

[0093] In this embodiment, a device for determining the position of a carrier is also provided, and the device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made are omitted. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0094] This embodiment provides a device for determining the position of a carrier, such as Figure 3 As shown, including:

[0095] The first acquisition module 301 is used to acquire one-dimensional distance information, the pixel coordinates of the laser measurement point in the image and the current state vector of the carrier; wherein the current state vector of the carrier related to the scale includes: the position of the image feature point, the historical carrier position in the sliding window at the current moment and the carrier speed at the current moment;

[0096] The first processing module 302 is used to track the pixel corresponding to the laser measurement point in the image as a new feature point, and triangulate it together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement point and other image feature points;

[0097] The detection and obtaining module 303 is used to detect whether the triangular facets within a preset range of the laser measurement point meet the coplanarity condition based on the three-dimensional coordinates of the laser measurement point and the image feature point, and to obtain the plane equation and the corresponding unit normal vector;

[0098] A first determination module 304 is used to determine a scale scaling factor based on a normal vector of the plane, a laser direction unit vector, one-dimensional distance information, and a triangulated laser point position;

[0099] The second determination module 305 is used to adjust the current state vector of the carrier based on the scale scaling factor to determine the carrier position.

[0100] In an optional embodiment, the above device further includes:

[0101] The second acquisition module is used to obtain the single-point laser distance measurement result and the external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device; wherein the laser measuring device is used to measure one-dimensional distance information, the shooting device is used to shoot images, and the external parameter information includes: the direction unit vector of the laser in the coordinate system of the shooting device and the position of the laser measuring device in the coordinate system of the shooting device;

[0102] A third determination module is used to determine the position of the laser measurement point in the coordinate system of the shooting device based on the single-point laser ranging result, the position of the laser measurement device in the coordinate system of the shooting device, and the laser direction unit vector in the coordinate system of the shooting device;

[0103] The fourth determination module is used to normalize the position of the laser measurement point in the coordinate system of the shooting device, and determine the pixel coordinates of the laser measurement point in the image according to the internal reference information.

[0104] In an optional implementation, the detection module 303 includes:

[0105] A triangulation unit is used to project the laser measurement points and the image feature points onto the normalized plane of the shooting device for Delaunay triangulation, and correspond the triangulation results to triangular facets in the three-dimensional space;

[0106] A first determining unit, used to determine the space normal vector corresponding to each triangular facet;

[0107] A second determination unit is used to determine the angle between adjacent triangular facets with the laser measurement point as a vertex based on the space normal vector;

[0108] A detection unit is used to detect whether the angle between adjacent triangular facets is not greater than a preset angle threshold. If the angle between adjacent triangular facets is not greater than the preset angle threshold, the vertices on the adjacent triangular facets are approximately coplanar, indicating that the coplanarity condition is met at the laser measurement point;

[0109] The first processing unit is used to obtain the plane equation by fitting the vertices on the adjacent triangular facets according to the least square method if the coplanarity condition is met at the laser measurement point, and to obtain the unit normal vector of the plane at the same time;

[0110] The second processing unit is used for not performing subsequent calculations if the coplanarity condition is not met, and waiting for the measurement result at the next moment to re-perform the coplanarity detection.

[0111] In an optional embodiment, the above-mentioned device also includes: a tracking processing module, which is used to track the pixels corresponding to the laser measurement point through the optical flow method, and after the number of continuous tracking times meets the preset number, the laser measurement point is triangulated to obtain the three-dimensional coordinates of the laser measurement point.

[0112] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0113] The carrier position determination device in this embodiment is presented in the form of a functional unit, where the functional unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0114] The embodiment of the present invention also provides a computer device having the above Figure 3 The device for determining the position of the carrier is shown.

[0115] See also Figure 4 , Figure 4 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Figure 4 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 4 A processor 10 is taken as an example.

[0116] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0117] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0118] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 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 optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device 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.

[0119] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0120] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0121] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0122] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0123] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for determining a carrier position, characterized in that: The method comprises: Obtain one-dimensional distance information, the pixel coordinates of the laser measurement point in the image, and the current state vector of the carrier; the current state vector of the carrier related to the scale includes: the position of the image feature point, the historical carrier position in the sliding window at the current moment, and the current carrier speed; The pixels corresponding to the laser measurement points in the image are tracked as new feature points, and triangulated together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement points and other image feature points; Based on the three-dimensional coordinates of the laser measurement point and the image feature point, detecting whether the coplanarity condition is met at the laser measurement point, and obtaining the equation and unit normal vector of the fitting plane; Determine the scale factor based on the plane normal vector, the laser direction unit vector, the one-dimensional distance information, and the position of the triangulated laser measurement point; The current state vector of the carrier is adjusted based on the scale scaling factor to determine the carrier position.

2. The method for determining the position of a carrier according to claim 1, characterized in that: The steps of determining the pixel coordinates of the laser measurement point in the image include: Obtaining a single-point laser distance measurement result and external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device; wherein the laser measuring device is used to measure one-dimensional distance information, the shooting device is used to shoot images, and the external parameter information includes: a unit vector of the direction of the laser in the coordinate system of the shooting device and a position of the laser measuring device in the coordinate system of the shooting device; Determine the position of the laser measurement point in the coordinate system of the shooting device based on the single-point laser ranging result, the position of the laser measurement device in the coordinate system of the shooting device, and the laser direction unit vector in the coordinate system of the shooting device; The position of the laser measurement point in the coordinate system of the shooting device is normalized, and the pixel coordinates of the laser measurement point in the image are determined based on the internal reference information.

3. The method for determining the position of a carrier according to claim 1, characterized in that: Based on the three-dimensional coordinates of the laser measurement point and the image feature point, whether the coplanarity condition is met at the laser measurement point is detected, and the equation and unit normal vector of the fitting plane are obtained, including: Projecting the laser measurement points and image feature points onto a normalized plane of a photographing device for Delaunay triangulation, and corresponding the triangulation result to a triangular facet in a three-dimensional space; Determine the space normal vector corresponding to each triangle face respectively; Based on the space normal vector, determining the angle between adjacent triangular facets with the laser measurement point as the vertex; Detecting whether the angles between the adjacent triangular facets are not greater than a preset angle threshold. If the angles between the adjacent triangular facets are not greater than the preset angle threshold, the vertices on the adjacent triangular facets are approximately coplanar, indicating that the coplanarity condition is satisfied at the laser measurement point. If the coplanarity condition is met at the laser measurement point, the plane equation is obtained by fitting the vertices on the adjacent triangular facets using the least square method, and the unit normal vector of the plane is obtained at the same time; If the coplanarity condition is not met, no subsequent calculation is performed, and the coplanarity test is performed again after waiting for the measurement result at the next moment.

4. The method for determining the position of a carrier according to claim 1, characterized in that: The steps for determining the three-dimensional coordinates of the laser measurement point include: The pixels corresponding to the laser measurement points are tracked by the optical flow method. After the number of continuous tracking times meets the preset number, the laser measurement points are triangulated to obtain the three-dimensional coordinates of the laser measurement points.

5. A device for determining a carrier position, characterized in that: The device comprises: The first acquisition module is used to obtain one-dimensional distance information, the pixel coordinates of the laser measurement point in the image and the current state vector of the carrier; wherein the current state vector of the carrier related to the scale includes: the position of the image feature point, the historical carrier position in the sliding window at the current moment and the carrier speed at the current moment; The first processing module is used to track the pixel coordinates corresponding to the laser measurement point in the image as new feature points, and triangulate them together with other successfully tracked image feature points to obtain the three-dimensional coordinates of the laser measurement point and other image feature points; A detection and obtaining module, used for detecting whether the coplanarity condition is satisfied at the laser measurement point based on the three-dimensional coordinates of the laser measurement point and the image feature point, and obtaining the equation and unit normal vector of the fitting plane; A first determination module is used to determine a scale scaling factor based on a normal vector of a plane, a laser direction unit vector, one-dimensional distance information, and a triangulated laser point position; The second determination module is used to adjust the current state vector of the carrier based on the scale scaling coefficient to determine the carrier position.

6. The device for determining the position of a carrier according to claim 5, characterized in that: Before obtaining the pixel coordinates of the laser measurement point in the image, the pixel coordinates need to be determined according to the internal and external parameters of the device. Therefore, the device also includes: A second acquisition module is used to acquire the single-point laser distance measurement result and the external parameter information of the laser measuring device relative to the shooting device in the coordinate system of the shooting device; wherein the laser measuring device is used to measure one-dimensional distance information, the shooting device is used to shoot images, and the external parameter information includes: the direction unit vector of the laser in the coordinate system of the shooting device and the position of the laser measuring device in the coordinate system of the shooting device; A third determination module is used to determine the position of the laser measurement point in the coordinate system of the shooting device based on the single-point laser ranging result, the position of the laser measurement device in the coordinate system of the shooting device, and the laser direction unit vector in the coordinate system of the shooting device; The fourth determination module is used to normalize the position of the laser measurement point in the coordinate system of the shooting device, and determine the pixel coordinates of the laser measurement point in the image according to the internal reference information.

7. The device for determining the position of a carrier according to claim 5, characterized in that: The detection module includes: A triangulation unit, used for projecting the laser measurement points and the image feature points onto a normalized plane of a photographing device for Delaunay triangulation, and corresponding the triangulation result to a triangular facet in a three-dimensional space; A first determining unit, used to determine the space normal vector corresponding to each triangular facet; A second determining unit is used to determine the angle between adjacent triangular facets with the laser measurement point as a vertex based on the space normal vector; A detection unit, used to detect whether the angle between the adjacent triangular facets is not greater than a preset angle threshold. If the angle between the adjacent triangular facets is not greater than the preset angle threshold, the vertices on the adjacent triangular facets are approximately coplanar, indicating that the coplanarity condition is met at the laser measurement point; A first processing unit is used to obtain a plane equation by fitting the vertices on the adjacent triangular facets according to the least square method if the coplanarity condition is satisfied at the laser measurement point, and to obtain a unit normal vector of the plane at the same time; The second processing unit is used for not performing subsequent calculations if the coplanarity condition is not met, and waiting for the measurement result at the next moment to re-perform the coplanarity detection.

8. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for determining the position of the carrier according to any one of claims 1 to 4 by executing the computer instructions.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method for determining the position of a carrier according to any one of claims 1 to 4.

10. A computer program product, characterized in that The method comprises computer instructions for causing a computer to execute the method for determining the position of a carrier according to any one of claims 1 to 4.

Images