Mileage calibration methods, devices, media, terminals, and testing vehicles for vehicles

Abstract

This invention belongs to the field of tunnel inspection technology and discloses a method, device, medium, terminal, and inspection vehicle for mileage calibration of a vehicle. The mileage calibration method includes: acquiring a first frame image of the tunnel taken by a first image acquisition device at the current time and a second frame image of the tunnel surface taken by a second image acquisition device at the current time; calculating the mileage of the vehicle based on the second frame image at the current time and historical frame images; and calibrating the mileage of the vehicle based on character information in the first frame image containing the mileage marker when the first frame image at the current time is detected to contain a mileage marker. This invention can improve the accuracy of mileage calibration for vehicles in tunnels.

Description

Technical Field

[0001] This invention relates to the field of tunnel inspection technology, and in particular to a method, device, medium, terminal, and inspection vehicle for mileage calibration of a vehicle. Background Technology

[0002] In real-world environments, some tunnels experience problems after construction due to complex and constantly changing geological conditions, such as lining cracking, segment cracking, misalignment, and tunnel leakage. Furthermore, issues like surrounding soil cavities and overall settlement of the subway tunnel may also arise. Therefore, construction personnel need to regularly inspect tunnel fault points, which requires locating tunnel inspection vehicles.

[0003] Existing methods for locating tunnel inspection vehicles rely on GPS (Global Positioning System) information and wheel rotations to calculate the tunnel's mileage and determine the vehicle's position. However, due to weak GPS signals within the tunnel, or even complete loss of signals in some areas, as well as wheel slippage, accurate positioning of the tunnel inspection vehicle becomes impossible. Therefore, machine vision-based positioning solutions for tunnel inspection vehicles have emerged.

[0004] Existing machine vision-based methods for locating tunnel inspection vehicles include:

[0005] Two frames of images are acquired, and the displacement difference between the two frames is determined by feature comparison. The actual position of the tunnel inspection vehicle is then calculated. However, due to various factors within the tunnel (such as tunnel surface discontinuities, railway stations, single-tunnel, and double-tunnel configurations), the clarity of the frame images changes with the surrounding environment, affecting the accuracy of machine vision-based tunnel inspection vehicle positioning. Therefore, achieving accurate positioning within the tunnel is a pressing issue that needs to be addressed.

[0006] Based on the above analysis, the problems and defects of the existing technology are as follows: due to the discontinuity of the tunnel surface inside the tunnel, the image frame of the station, single tunnel, double tunnel, etc., will change in clarity as the surrounding environment changes, resulting in very low accuracy of machine vision-based positioning of tunnel inspection vehicles. Summary of the Invention

[0007] The purpose of this invention is to provide a method, device, medium, terminal, and testing vehicle for mileage calibration of a vehicle, so as to improve the accuracy of positioning in tunnels.

[0008] The specific technical solution is as follows: A method for calibrating the mileage of a vehicle, wherein mileage markers are set in areas not covered by communication networks, and the mileage markers are marked with character information. The areas not covered by communication networks include underground pipelines or tunnels and utility corridors in mountainous areas, and areas where GPS signals are weak and not covered by communication networks. The method specifically includes the following steps:

[0009] The first image capture device captures a first frame image of an area not covered by the communication network at the current time, and the second image capture device captures a second frame image of the road surface in the area not covered by the communication network at the current time.

[0010] The first image capturing device and the second image capturing device move synchronously with the vehicle. The shooting angle of the first image capturing device is between the vertical area not covered by the communication network and the horizontal area not covered by the communication network.

[0011] The mileage of the vehicle is calculated based on the second frame image at the current time and the historical frame image, wherein the historical frame image is the first frame image used when the vehicle was last calibrated.

[0012] When the first frame image at the current time is detected to contain the mileage marker, the character information of the first frame image containing the mileage marker is identified to obtain a recognition result, wherein the recognition result is: whether the character information in the first frame image is identified;

[0013] When valid mileage information can be identified in the first frame image at the current time, the mileage of the vehicle is calibrated based on the character information in the first frame image containing the mileage marker at the current time.

[0014] Optionally, before the step of calibrating the mileage of the vehicle based on the character information in the first frame image containing the mileage marker at the current time, the method further includes:

[0015] When the first frame image at the current time is detected to contain the mileage marker, the character information of the first frame image containing the mileage marker is identified to obtain a recognition result, wherein the recognition result is: whether the character information in the first frame image is identified;

[0016] When the recognition result is that the character information is not recognized, the second historical frame image of the mileage detection surface in the area not covered by the communication network is obtained from the time from the last time the mileage of the driving tool was calibrated to the current time.

[0017] Based on the second historical frame image, the cumulative mileage of the vehicle is calculated;

[0018] Sum the mileage from the last calibration with the preset value to obtain the first summation result;

[0019] The mileage from the last calibration is summed with the cumulative mileage to obtain a second summation result;

[0020] The step of calibrating the mileage of the vehicle based on character information in the first frame image containing the mileage marker at the current time includes:

[0021] The first summation result is compared with the second summation result to calibrate the mileage of the vehicle at the current time;

[0022] The step of comparing the first summation result with the second summation result to calibrate the mileage of the vehicle at the current time includes:

[0023] When the difference between the first summation result and the second summation result does not exceed the first difference threshold, the difference between the first summation result and the preset second value is determined as the mileage of the vehicle at the current time.

[0024] When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time. In practical applications, the first difference threshold is set according to actual needs and is not specifically limited here. The preset second value is set according to actual needs and is not elaborated here.

[0025] Furthermore, when the first frame image at the current time is detected to contain a mileage marker, the calibration of the vehicle's mileage before calibrating it based on the character information in the first frame image containing the mileage marker at the current time also includes:

[0026] Detect whether the first frame of the image at the current time contains a mileage marker;

[0027] When there are multiple first frame images containing mileage markers, the target frame image is determined from the multiple first frame images. The target frame image is the first frame image whose center point is closest to the center point of the mileage marker.

[0028] The steps for calibrating the mileage of a vehicle based on character information in the first frame image containing odometer markers at the current time include:

[0029] The mileage of the vehicle is calibrated based on the character information in the target frame image.

[0030] Furthermore, after detecting whether the first frame of the image at the current time contains odometer markers, the following steps are also included:

[0031] When there are multiple first-frame images containing mileage markers, the character information of the mileage markers in each first-frame image containing mileage markers is identified to obtain the recognition result, which is: whether the character information is recognized.

[0032] For the recognition results of the identified character information, count the number of times the character information in the recognition results is the same as the other character information.

[0033] When the number of identical characters in the recognition result exceeds a preset threshold, the mileage of the vehicle at the current time is calibrated based on the number of identical characters exceeding the preset threshold.

[0034] Furthermore, the character information includes: the distance between the mileage marker and the starting point;

[0035] When the first frame of the current time is detected to contain a mileage marker, the steps for calibrating the vehicle's mileage based on the character information in the first frame of the current time containing the mileage marker include:

[0036] The distance of the mileage marker from the starting point is summed with the initial mileage of the vehicle, and the sum is determined as the mileage of the vehicle at the current time.

[0037] Furthermore, based on the character information in the first frame image containing the odometer marker at the current time, the odometer of the vehicle is calibrated as follows:

[0038] When the recognition result is that character information is recognized, the character information includes: the distance of the mileage marker from the starting point, and whether the difference between the distance in the historical character information and the distance in the current time character information exceeds the second difference threshold. The historical character information is the character information of the last mileage calibration.

[0039] When the difference between the distance in the current time character information and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the current time character information and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time.

[0040] When the difference between the distance in the current time character information and the distance in the historical character information exceeds the second difference threshold, acquire the second historical frame image captured by the second image acquisition device from the last calibration of the driving vehicle mileage to the current time.

[0041] Calculate the cumulative mileage based on the second historical frame image;

[0042] The sum of the accumulated mileage and the distance in the historical character information is determined as the mileage of the vehicle at the current time.

[0043] Furthermore, the step of calculating the cumulative mileage based on the historical second frame image includes:

[0044] Calculate the actual size of the object space corresponding to each pixel in the second historical frame image;

[0045] Using a preset matching algorithm, the homography matrix of adjacent historical second-frame images is calculated. The homography matrix represents the magnitude of the change between adjacent historical second-frame images.

[0046] Based on the homography matrix, calculate the image displacement of the next historical second frame image relative to the previous historical second frame image in adjacent historical second frame images;

[0047] Based on the actual size of the object space corresponding to each pixel, determine the actual displacement of the second historical frame image of the next frame relative to the second historical frame image of the previous frame.

[0048] The actual displacement is accumulated to determine the cumulative mileage.

[0049] Furthermore, following the step of calibrating the mileage of a vehicle based on character information in the first frame image containing mileage markers at the current time, the mileage calibration method for a vehicle provided in the first aspect embodiment of the present invention further includes:

[0050] Based on the calibrated mileage of the vehicle and tunnel information, the position of the vehicle in the tunnel is determined. The tunnel information includes: the length of the tunnel, the location of the tunnel entrance, the location of the tunnel exit, and the curvature angle of the tunnel at different locations.

[0051] Another object of the present invention is to provide a mileage calibration device for a vehicle, comprising:

[0052] The first image capturing device is used to capture the tunnel at the current time and obtain the first frame image;

[0053] The second image capturing device is used to capture a picture of the tunnel surface at the current time to obtain a second frame image;

[0054] The decision-making device is used to connect to both the first image acquisition device and the second image acquisition device.

[0055] The first image of the tunnel is captured by the first image capturing device at the current time, and the second image capturing device is captured by the second image capturing device at the current time;

[0056] The mileage of the vehicle is calculated based on the second frame image at the current time and the historical frame image, which is the first frame image used when the vehicle was last calibrated.

[0057] When the first frame of the current time is detected to contain a mileage marker, the mileage of the vehicle is calibrated based on the character information in the first frame of the current time containing the mileage marker.

[0058] Furthermore, the mileage calibration device for the vehicle also includes: a detection device, used to identify character information of the first frame image containing the mileage marker when the first frame image of the current time is detected to contain a mileage marker, and obtain a recognition result, the recognition result being: whether the character information in the first frame image is recognized;

[0059] When the recognition result is that no character information is recognized, the second historical frame image of the tunnel surface is obtained from the time of the last calibration of the driving vehicle mileage to the current time;

[0060] Calculate the cumulative mileage of the vehicle based on the second historical frame image;

[0061] Sum the mileage from the last calibration with the preset value to obtain the first summation result;

[0062] Sum the mileage from the last calibration with the cumulative mileage to obtain the second summation result;

[0063] The detection device is also used for:

[0064] Detect whether the first frame of the image at the current time contains a mileage marker;

[0065] When there are multiple first frame images containing mileage markers, the target frame image is determined from the multiple first frame images. The target frame image is the first frame image whose center point is closest to the center point of the mileage marker.

[0066] The detection device is also used for:

[0067] Calculate the actual size of the object space corresponding to each pixel in the second historical frame image;

[0068] Using a preset matching algorithm, the homography matrix of adjacent historical second-frame images is calculated. The homography matrix represents the magnitude of the change between adjacent historical second-frame images.

[0069] Based on the homography matrix, calculate the image displacement of the next historical second frame image relative to the previous historical second frame image in adjacent historical second frame images;

[0070] Based on the actual size of the object space corresponding to each pixel, determine the actual displacement of the second historical frame image of the next frame relative to the second historical frame image of the previous frame.

[0071] The actual displacement is accumulated to determine the cumulative mileage.

[0072] The decision module compares the first summation result with the second summation result to calibrate the mileage of the vehicle at the current time.

[0073] The decision module is also used to determine the difference between the first summation result and the preset second value as the mileage of the vehicle at the current time when the difference between the first summation result and the second summation result does not exceed the first difference threshold.

[0074] When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time.

[0075] Furthermore, the decision-making module is also used for:

[0076] The mileage of the vehicle is calibrated based on the character information in the target frame image. The character information includes the distance between the mileage marker and the starting point.

[0077] Furthermore, the mileage calibration device of the driving vehicle also includes: a recognition device, used to recognize the character information of the mileage marker in each first frame image containing the mileage marker when there are multiple first frame images containing the mileage marker, and obtain a recognition result, the recognition result being: whether the character information is recognized;

[0078] For the recognition results of the identified character information, count the number of times the character information in the recognition results is the same as the other character information.

[0079] When the number of identical characters in the recognition result exceeds a preset threshold, the mileage of the vehicle at the current time is calibrated based on the number of identical characters exceeding the preset threshold.

[0080] The decision-making module is specifically used for:

[0081] The distance of the mileage marker from the starting point is summed with the initial mileage of the vehicle, and the sum is determined as the mileage of the vehicle at the current time.

[0082] The decision module is also used for:

[0083] When the recognition result is that character information is recognized, the character information includes: the distance of the mileage marker from the starting point, and whether the difference between the distance in the historical character information and the distance in the current time character information exceeds the second difference threshold. The historical character information is the character information of the last mileage calibration.

[0084] When the difference between the distance in the current time character information and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the current time character information and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time.

[0085] When the difference between the distance in the current time character information and the distance in the historical character information exceeds the second difference threshold, acquire the second historical frame image captured by the second image acquisition device from the last calibration of the driving vehicle mileage to the current time.

[0086] Calculate the cumulative mileage based on the second historical frame image;

[0087] The sum of the accumulated mileage and the distance in the historical character information is determined as the mileage of the vehicle at the current time.

[0088] Furthermore, the mileage calibration device for the vehicle also includes a positioning device, used to determine the position of the vehicle in the tunnel based on the calibrated mileage and tunnel information. The tunnel information includes the length of the tunnel, the location of the tunnel entrance, the location of the tunnel exit, and the curvature angle of the tunnel at different locations.

[0089] Another object of the present invention is to provide a server, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; a machine-readable storage medium stores machine-executable instructions that can be executed by the processor, and the processor is prompted by the machine-executable instructions to implement the steps of the mileage calibration method for the driving vehicle described in the present invention.

[0090] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to perform the steps of a mileage calibration method for a vehicle provided by the present invention.

[0091] Another object of the present invention is to provide a testing vehicle equipped with the mileage calibration device of the aforementioned driving vehicle.

[0092] Based on the above technical solutions and the technical problems solved, please analyze the advantages and positive effects of the technical solution to be protected by this invention from the following aspects:

[0093] First, addressing the technical problems existing in the prior art and the difficulty in solving them, this paper closely analyzes, in conjunction with the technical solution to be protected by this invention and the results and data obtained during the research and development process, how the technical solution of this invention solves the technical problems, and the inventive technical effects brought about by solving these problems. The specific description is as follows:

[0094] In existing technologies, underground pipelines or tunnels and utility corridors in mountainous areas are not covered by communication networks, and GPS signals are weak, making it impossible to provide positioning information for moving equipment.

[0095] The method of measuring mileage by relying on the wheel circumference and the number of rotations may be affected by factors such as wheel slippage or low air pressure, which can affect the accuracy of the measurement.

[0096] To solve the above problems, the driving device of the present invention can break free from the limitations of communication networks or GPS and complete high-precision positioning calculations on its own.

[0097] This invention calculates the displacement of the driving equipment using a homography matrix, eliminating the influence of various factors such as the temperature and material of the driving equipment wheels and road surface, acceleration, and braking temperature and humidity on the mileage.

[0098] This invention divides a complete tunnel into several small sections and, by identifying the mileage information in the mileage markers, repeatedly calibrates the position information to further improve the accuracy of precise positioning.

[0099] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by this invention are specifically described as follows:

[0100] This invention provides a method and apparatus for calibrating the mileage of a vehicle. It acquires a first frame image of a tunnel captured by a first image acquisition device at the current time, and a second frame image of the tunnel surface captured by a second image acquisition device at the current time. Based on the second frame image at the current time and historical frame images, the mileage of the vehicle is calculated. When the first frame image at the current time contains a mileage marker, the mileage of the vehicle is calibrated based on character information in the first frame image containing the mileage marker. Compared to existing technologies, this invention improves the accuracy of mileage calibration in tunnels by identifying character information in the first frame image containing mileage markers with high positioning accuracy and prominent image features, and then calibrating the mileage calculated based on the second frame image and historical frame images using this character information. This enhances the accuracy of vehicle positioning in tunnels.

[0101] Third, as supporting evidence of the inventiveness of this invention, it is also reflected in the following important aspects:

[0102] The technical solution of this invention fills a technological gap in the industry both domestically and internationally: this invention achieves high-precision positioning within tunnels without relying on infrastructure such as GPS or communication networks, thus filling a gap in this field both domestically and internationally.

[0103] The technical solution of this invention solves a technical problem that people have long desired to solve but have never been able to achieve: This invention provides a practical and effective method and device description for achieving high-precision positioning of driving equipment in underground or mountainous areas where communication networks are not covered, such as tunnels and pipe corridors, thus solving the urgent problem of inaccurate positioning in current tunnel construction, inspection, maintenance, and repair operations.

[0104] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0105] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0106] Figure 1 A flowchart of a mileage calibration method for a vehicle provided in an embodiment of the present invention;

[0107] Figure 2 A flowchart of the implementation step S14 provided in an embodiment of the present invention;

[0108] Figure 3 A flowchart for calculating cumulative mileage provided in an embodiment of the present invention;

[0109] Figure 4 This is a structural diagram of the mileage calibration device for a driving vehicle provided in an embodiment of the present invention;

[0110] In the figure: 41, first image acquisition device; 42, second image acquisition device; 43, decision-making device; 44, detection device; 45, decision-making module; 46, recognition device; 47, positioning device. Detailed Implementation

[0111] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0112] I. Explanation and Description of Embodiments. To enable those skilled in the art to fully understand how the present invention is specifically implemented, this section provides an explanation and description of the embodiments that elaborate on the technical solutions.

[0113] The mileage calibration method for driving vehicles provided in this embodiment of the invention can be applied to areas not covered by communication networks, including underground pipelines or tunnels and utility corridors in mountainous areas, where GPS signals are weak.

[0114] The following description uses a tunnel as an example to further illustrate the mileage calibration method for a driving vehicle provided in this embodiment of the invention. Example

[0115] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for calibrating the mileage of a vehicle, comprising:

[0116] S11, acquire the first frame image of the tunnel captured by the first image capturing device at the current time, and the second frame image of the tunnel surface captured by the second image capturing device at the current time;

[0117] The first and second image capturing devices move synchronously with the vehicle. The shooting angle of the first image capturing device is between the vertical tunnel wall and the parallel tunnel wall. Mileage markers are set up next to the tunnel, and the mileage markers are marked with character information. The character information includes: the distance of the mileage marker from the starting point.

[0118] It is understood that the vehicle can be a car, subway, light rail, train, or other transportation vehicle, or an engineering vehicle used for tunnel inspection, or a trailer attached to an engineering vehicle, equipped with an image acquisition device. The first and second image acquisition devices can be cameras, cameras, or other devices with shooting capabilities. The camera of the first image acquisition device can capture images of the mileage markers inside the tunnel. The starting point can be at the tunnel entrance, or at a point some distance from the tunnel entrance; this starting point varies depending on the actual situation and serves as the initial position used by engineers to calibrate the distances on the mileage markers.

[0119] Taking engineering vehicles as an example, existing tunnels are equipped with mileage markers at predetermined locations. These markers can be 100-meter markers, 50-meter markers, etc. The mileage markers record the distance from the tunnel entrance to the marker and also indicate the vehicle's direction of travel. Engineers can use these markers to determine the marker's position within the tunnel and its distance from the starting point. Since tunnels are two-way passages, the mileage markers can have both sides. Engineers entering from the tunnel entrance can mark the distance from the entrance on the front and the distance from the exit on the back. Alternatively, the markers can mark the distance from the starting point on both sides, with the markings varying according to the actual situation.

[0120] In this invention, the mileage markers are signs set by technicians through precise measurements, resulting in high accuracy. Within the tunnel, the mileage markers are visually distinct from the surrounding environment. Experiments have shown that the features of the mileage markers in the image are more prominent than those of surrounding lights or markings on the tunnel walls, and they are less affected by the surrounding environment, resulting in higher accuracy for machine vision recognition.

[0121] For example, when the engineering vehicle activates its camera function, if the mileage marker is within the vehicle's camera range during the vehicle's movement, the vehicle can capture the first frame image containing the mileage marker; if the mileage marker is not within the vehicle's camera range, the first frame image will only contain images of the environment surrounding the tunnel, such as the tunnel walls, tunnel surface, and tunnel lights.

[0122] When the mileage marker is affixed to the tunnel wall, the camera of the first image capturing device can be positioned on the side wall of the construction vehicle, facing the tunnel wall. When the mileage marker is placed next to the tunnel wall, with its face facing the construction vehicle, the camera can be positioned in front of the construction vehicle, or positioned within a 90-degree range to the left and right of the vehicle's central axis in the direction of travel. Of course, the height of the camera should differ from the height of the mileage marker within a preset range to ensure that the mileage marker can enter the camera's field of view. This camera can be a movable lens camera, used to rotate and capture images of the mileage marker within a 0-degree range in the direction of travel and a 180-degree range in the opposite direction of travel.

[0123] It is understandable that mileage markers are highly distinctive, detailed, and accurately positioned, thus ensuring their reliability and usability. Furthermore, using mileage markers to locate vehicles requires only two image acquisition devices, making the solution easy to implement and inexpensive.

[0124] S12, calculate the mileage of the vehicle based on the second frame image at the current time and the historical frame images.

[0125] Among them, the historical frame image is the first frame image used during the last calibration of the driving vehicle.

[0126] It's understandable that the cumulative mileage is calculated using the second frame image before the current time. The initial mileage value of the vehicle is then added to the cumulative mileage to obtain the vehicle's cumulative mileage. If the vehicle's mileage was previously calibrated, and the vehicle continues to travel to its current position at the current time, there are multiple frames between the second frame image of the current time and the historical frame images. The mileage from the previous calibration is added to the cumulative mileage calculated from these multiple frames to obtain the vehicle's current mileage.

[0127] S13, when valid mileage information can be identified in the first frame image at the current time, the mileage of the driving vehicle is calibrated based on the character information in the first frame image containing the mileage marker at the current time.

[0128] It is understood that the features of mileage markers are relatively obvious in the image. When searching for the first frame image containing mileage markers, feature points of the mileage markers can be extracted, such as SIFT (Scale Invariant Feature Transform) feature points and corner points. This invention does not impose any limitations on these features.

[0129] It is understandable that by comparing the distance recorded on the mileage marker from the starting point with the distance recorded in the character information, the mileage of the vehicle can be calibrated.

[0130] This invention provides a method for calibrating the mileage of a vehicle. It acquires a first frame image of a tunnel captured by a first image acquisition device at the current time, and a second frame image of the tunnel surface captured by a second image acquisition device at the current time. Based on the second frame image at the current time and historical frame images, the mileage of the vehicle is calculated. When the first frame image at the current time is detected to contain a mileage marker, the mileage of the vehicle is calibrated based on the character information in the first frame image containing the mileage marker. Compared to existing technologies, this invention improves the accuracy of mileage measurement in tunnels by identifying character information in the first frame image containing mileage markers with high positioning accuracy and prominent image features. This character information is then used to calibrate the mileage calculated based on the second frame image and historical frame images, thereby enhancing the accuracy of vehicle positioning in tunnels. Example

[0131] As one possible implementation method of the present invention, such as Figure 2 As shown, prior to step S13 above, the mileage calibration method for a driving vehicle provided in this embodiment of the invention further includes:

[0132] S21, when the first frame image of the current time is detected to contain a mileage marker, the character information of the first frame image containing the mileage marker is identified to obtain the identification result.

[0133] The recognition result is whether the character information in the first frame image is recognized.

[0134] It is understandable that when recognizing the character information of mileage markers in the first frame image containing them, the image's clarity, scale, or position within the frame can affect the results. For example, when only part of the mileage marker is in the first frame image, the character information cannot be recognized due to missing text.

[0135] S22, when the recognition result is that no character information is recognized, acquire the second historical frame image of the tunnel surface captured by the second image acquisition device from the last time the driving vehicle mileage was calibrated to the current time;

[0136] It is understandable that if the recognition result is that no character information is recognized, it means that the distance of the mileage marker from the starting point cannot be obtained, and therefore the mileage marker cannot be used to calibrate the mileage of the vehicle at the current time. In this case, the frame image from the last mileage calibration to the current time is needed to know the distance traveled by the vehicle from the last mileage calibration to the current time.

[0137] S23, Calculate the cumulative mileage of the vehicle based on the second historical frame image;

[0138] It is understandable that when a vehicle is moving, there is a displacement difference between adjacent historical second-frame images. Based on the displacement difference between adjacent historical second-frame images, the cumulative mileage of the vehicle from the last calibration mileage to the current time can be determined.

[0139] S24, sum the mileage from the last calibration with the preset value to obtain the first summation result;

[0140] The first value is the distance between adjacent mileage markers.

[0141] It's understandable that once the vehicle enters the tunnel, all captured frame images can be stored in a database, which could be an onboard database or a cloud database. The vehicle uploads the captured frame images to the cloud database and records the capture time of each frame image. When a frame image is needed, it can be retrieved from the database. Simultaneously, the time of each mileage calibration is recorded. If the mileage marker recognition fails at the current time, the mileage from the last calibration is added to the distance between the two adjacent mileage markers to determine the vehicle's mileage at the current time.

[0142] S25 sums the mileage from the last calibration with the cumulative mileage to obtain a second summation result.

[0143] Furthermore, step S13 above can compare the first summation result with the second summation result to calibrate the mileage of the vehicle at the current time. Example

[0144] As an optional implementation method of the present invention, combined with Figure 1 as well as Figure 2 The step of comparing the first summation result with the second summation result to calibrate the vehicle's mileage at the current time is achieved through the following steps:

[0145] Step 1: When the difference between the first summation result and the second summation result does not exceed the first difference threshold, the difference between the first summation result and the preset second value is determined as the mileage of the vehicle at the current time;

[0146] The second value is the distance between the actual location of the mile marker in the tunnel and the camera in the first frame image, i.e., the object distance.

[0147] It is understood that the object distance will be different if different frame images containing the same mileage marker are selected. In this embodiment of the invention, the object distance selected for each mileage calibration is the same, that is, if the selected frame image containing the same mileage marker is a single image, then the position of the mileage marker in the first frame image is the same each time the mileage is calibrated.

[0148] For example, suppose that when a mileage marker is selected to enter the camera's shooting range, the first frame captured by the camera contains an image of the mileage marker; the nth frame captured by the camera contains an image of the mileage marker. The distance between the mileage marker and the camera is different in these two frames, and the value of the second value is different.

[0149] Step 2: When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time.

[0150] The first difference threshold is a value preset based on tunnel length and practical experience, and can be set to 10 meters in actual application.

[0151] It's understandable that the camera might have already captured a frame containing the mileage marker before the vehicle even reaches it; the distance between the vehicle and the marker at this point is the second value. The estimated mileage is then verified by comparing the first and second summations to determine if it meets the accuracy standard. If so, the difference between the second summation and the second value is taken to obtain the vehicle's mileage at the current time. The estimated mileage is the result of the first summation. Example

[0152] As an optional implementation of the present invention, before step S13 above, the mileage calibration method for a driving tool provided by the present invention further includes:

[0153] Step 1: Detect whether the first frame of the current time contains mileage markers;

[0154] Step 2: When there are multiple first frame images containing mileage markers, determine the target frame image from the multiple first frame images. The target frame image is the first frame image whose center point is closest to the center point of the mileage marker.

[0155] Furthermore, step S13 above can be used to calibrate the mileage of the vehicle based on the character information in the target frame image.

[0156] This implementation method can calculate the center coordinates (x, y) of the same mile marker in multiple consecutive frames of images. i ,y i ), (i = 1…n), where n represents the number of frames captured by the camera containing the same mileage marker, and then the distance Dist between the center coordinates of the mileage marker and the center coordinates of the frame image is calculated. i (i = 1…n), select the frame image with the smallest distance as the target frame image.

[0157] This embodiment calculates the distance between the center coordinates of the mileage marker in the frame image and the center coordinates of the frame image, and selects the frame image with the smallest distance as the target frame image, so that the mileage marker is as close to the center of the frame image as possible, thereby improving the accuracy of character information recognition and mileage calibration. Example

[0158] As an optional embodiment of the present invention, after the step of detecting whether the first frame image at the current time contains a mileage marker, the mileage calibration method for a driving vehicle provided by the present invention further includes:

[0159] Step 1: When there are multiple first-frame images containing mileage markers, identify the character information of the mileage markers in each first-frame image containing mileage markers to obtain the recognition result.

[0160] The recognition result is whether character information was recognized.

[0161] It is understandable that when a mileage marker enters the shooting range of the first image capturing device, if the vehicle is moving, the first image capturing device may capture multiple target frame images containing the mileage marker.

[0162] Step 2: For the recognition results of the identified character information, count the number of times the character information in the recognition results is the same as the other character information;

[0163] Step 3: When the number of identical characters in the recognition result exceeds a preset threshold, the mileage of the vehicle at the current time is calibrated based on the number of identical characters exceeding the preset threshold.

[0164] It is understandable that some areas in some frame images may be blurry. When there are multiple frame images containing the same mileage marker, the text information in multiple frame images can be identified to determine the same character information of the same mileage marker and the number of the same character information. Based on the distance corresponding to the character information whose number exceeds the threshold, the mileage of the driving vehicle at the current time can be calibrated, which can improve the reliability of calibrating the mileage of the driving vehicle at the current time.

[0165] As an optional implementation of the present invention, the mileage of the vehicle can be calibrated by summing the distance of the mileage marker from the starting point to the initial mileage of the vehicle, and the summation result is determined as the mileage of the vehicle at the current time. Example

[0166] As one possible implementation method of the present invention, such as Figure 3 As shown, step S13 above can be implemented as follows:

[0167] S31, when the recognition result is that character information is recognized, determine whether the difference between the distance in the historical character information and the distance in the current time character information exceeds the second difference threshold. The historical character information is the character information of the last calibrated mileage.

[0168] The character information includes the distance of the mileage marker from the starting point.

[0169] S32, when the difference between the distance in the character information at the current time and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the character information at the current time and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time;

[0170] The second difference threshold is a preset value, which can be 10 meters in practice.

[0171] S33, when the difference between the distance in the character information at the current time and the distance in the historical character information exceeds the second difference threshold, acquire the second historical frame image captured by the second image capturing device from the last calibration of the driving vehicle mileage to the current time;

[0172] S34, calculate the cumulative mileage based on the second historical frame image;

[0173] S35 determines the mileage of the vehicle at the current time by summing the accumulated mileage with the distance in the historical character information.

[0174] It is understood that this embodiment compares the distance in the character information of the current time with the distance in the historical character information to determine whether the frame image containing the mileage marker at the current time can be used to calibrate the mileage, thereby improving the accuracy of calibrating the mileage of the driving vehicle. Example

[0175] As an optional implementation of this invention, the step of calculating the cumulative mileage based on the historical second frame image includes:

[0176] Step 1: Calculate the actual size of the object space corresponding to each pixel in the second historical frame image;

[0177] Step 2: Using a preset matching algorithm, calculate the homography matrix of adjacent historical second-frame images. The homography matrix represents the magnitude of change between adjacent historical second-frame images.

[0178] Step 3: Based on the homography matrix, calculate the image displacement of the next historical second frame image relative to the previous historical second frame image in adjacent historical second frame images;

[0179] Step 4: Based on the actual size of the object space corresponding to each pixel, determine the actual displacement of the next historical second frame image relative to the previous historical second frame image.

[0180] Step 5: Accumulate the actual displacement to determine the cumulative mileage.

[0181] It can be understood that if the image displacement of the next frame relative to the previous frame is x, and the actual size of the object space corresponding to each pixel is d, then the actual displacement of the next historical frame relative to the previous historical frame is s = d*x. Example

[0182] As an optional implementation of the present invention, after step S13 above, the mileage calibration method for a driving tool provided by the present invention further includes:

[0183] Based on the calibrated mileage of the vehicle and tunnel information, the position of the vehicle in the tunnel is determined. The tunnel information includes: the length of the tunnel, the location of the tunnel entrance, the location of the tunnel exit, and the curvature angle of the tunnel at different locations.

[0184] It's understandable that when a construction vehicle is in a tunnel, the distance traveled within the tunnel can be determined based on the mileage. Knowing this distance, the vehicle's exact location within the tunnel can be determined using tunnel information. For tunnels with significant curvature, the direction of the construction vehicle needs to be determined based on the tunnel's curvature angle, and then the distance traveled can be used to pinpoint the vehicle's exact location within the tunnel. Example

[0185] As an optional implementation of the present invention, a trained region recognition model can be used to find the first frame image containing mileage markers in the frame image.

[0186] The region recognition model can be a Cascade R-CNN model. The process of obtaining a trained region recognition model is as follows:

[0187] Step 1: Obtain the sample set, which includes frame images containing mileage markers collected at different locations. Each frame image is a sample.

[0188] Step 2: Label the samples in the sample set, indicating the location of the mileage markers in the tunnel.

[0189] Step 3: Input standard samples into the preset network model, use the standard results as the training target of the Cascade RCNN model, and iteratively adjust the internal parameters of the network model until the number of iterations or the training target is reached.

[0190] Step 4: Use the network model that has reached the required number of iterations or the training target as the training number for the trained network model.

[0191] It is understood that this embodiment trains a region recognition model using standard samples, and using this region recognition model to recognize frame images can improve the accuracy of the recognition results. Example

[0192] As an optional implementation of the present invention, a trained character recognition model can be used to recognize character information in the first frame image containing mileage markers.

[0193] The character recognition model can be a ResNet model. The process of obtaining a trained character recognition model is as follows:

[0194] Step 1: Collect the different types of characters contained in the mileage marker images and use each character as a training sample.

[0195] Step 2: For each training sample, input the training sample into the preset character recognition model, use the distance information corresponding to the training sample as the training target, and iteratively train the preset character recognition model until the number of iterations is reached to obtain the trained character recognition model.

[0196] It is understood that this embodiment trains a character recognition model by using different types of characters contained in the mileage marker image, and using the character recognition model to recognize the frame image can improve the accuracy of the recognition results. Example

[0197] As an optional embodiment of the present invention, before step S11 above, the mileage calibration method for a driving tool provided by the present invention further includes calibrating a camera.

[0198] The steps for calibrating a camera are as follows:

[0199] (a) Keep the camera position fixed, place the calibration plate at different positions in the tunnel, collect m frames of images, and detect corner points in the frames. Assume that n corner points can be detected in each frame.

[0200] (b) Iterate through each frame of the image and solve for the homography matrix H. j H j The initial value is used to perform nonlinear optimization on the identity matrix; j represents the sequence number of the frame image.

[0201] (c) Solve for the camera intrinsic parameter matrix K;

[0202] (d) Solve for the camera's extrinsic parameters and calculate R. j and t j .

[0203] Among them, R j Let t represent the rotation matrix. j This represents the translation vector.

[0204] (e) Solve for the camera distortion coefficients K1 and K2.

[0205] (f) Parameter optimization: Optimize K and R using nonlinear least squares method. j t j K1 and K2 are used to obtain the camera's intrinsic and extrinsic parameters. Example

[0206] like Figure 4 As shown, an embodiment of the present invention provides a mileage calibration device for a vehicle, comprising:

[0207] The first image capturing device 41 is used to capture the tunnel at the current time and obtain the first frame image;

[0208] The second image capturing device 42 is used to capture the tunnel surface at the current time to obtain a second frame image;

[0209] Decision-making device 43 is used to connect to the first image capturing device and the second image capturing device respectively.

[0210] The first image of the tunnel is captured by the first image capturing device at the current time, and the second image capturing device is captured by the second image capturing device at the current time;

[0211] The mileage of the vehicle is calculated based on the second frame image at the current time and the historical frame image, which is the first frame image used when the vehicle was last calibrated.

[0212] When the first frame of the current time is detected to contain a mileage marker, the mileage of the vehicle is calibrated based on the character information in the first frame of the current time containing the mileage marker.

[0213] Optionally, the mileage calibration device for a driving tool provided in this embodiment of the invention further includes: a detection device 44, used to identify character information of the first frame image containing the mileage marker when the first frame image of the current time is detected to contain a mileage marker, and obtain a recognition result, wherein the recognition result is: whether the character information in the first frame image is recognized;

[0214] When the recognition result is that no character information is recognized, the second historical frame image of the tunnel surface is obtained from the time of the last calibration of the driving vehicle mileage to the current time;

[0215] Calculate the cumulative mileage of the vehicle based on the second historical frame image;

[0216] Sum the mileage from the last calibration with the preset value to obtain the first summation result;

[0217] Sum the mileage from the last calibration with the cumulative mileage to obtain the second summation result;

[0218] Decision module 45 is used to compare the first summation result with the second summation result and calibrate the mileage of the vehicle at the current time.

[0219] Optionally, the decision module is used to determine the difference between the first summation result and a preset second value as the mileage of the vehicle at the current time when the difference between the first summation result and the second summation result does not exceed the first difference threshold.

[0220] When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time.

[0221] Optionally, the detection device 44 is used to detect whether the first frame image at the current time contains a mileage marker;

[0222] When there are multiple first frame images containing mileage markers, the target frame image is determined from the multiple first frame images. The target frame image is the first frame image whose center point is closest to the center point of the mileage marker.

[0223] Furthermore, the decision module 45 is used to calibrate the mileage of the driving vehicle based on the character information in the target frame image.

[0224] Optionally, the mileage calibration device for a driving tool provided in this embodiment of the invention further includes: an identification device 46, used to identify the character information of the mileage marker in each first frame image containing the mileage marker when there are multiple first frame images containing mileage markers, and obtain an identification result, wherein the identification result is: whether the character information is identified;

[0225] For the recognition results of the identified character information, count the number of times the character information in the recognition results is the same as the other character information.

[0226] When the number of identical characters in the recognition result exceeds a preset threshold, the mileage of the vehicle at the current time is calibrated based on the number of identical characters exceeding the preset threshold.

[0227] Optional, the character information includes: the distance between the mileage marker and the starting point;

[0228] Furthermore, the decision module 45 is specifically used to sum the distance of the mileage marker from the starting point with the initial mileage of the vehicle, and determine the sum as the mileage of the vehicle at the current time.

[0229] Optionally, a decision module is used when the recognition result is that character information is recognized. The character information includes: the distance of the mileage marker from the starting point. It determines whether the difference between the distance in the historical character information and the distance in the current time character information exceeds a second difference threshold. The historical character information is the character information of the last mileage calibration.

[0230] When the difference between the distance in the current time character information and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the current time character information and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time.

[0231] When the difference between the distance in the current time character information and the distance in the historical character information exceeds the second difference threshold, acquire the second historical frame image captured by the second image acquisition device from the last calibration of the driving vehicle mileage to the current time.

[0232] Calculate the cumulative mileage based on the second historical frame image;

[0233] The sum of the accumulated mileage and the distance in the historical character information is determined as the mileage of the vehicle at the current time.

[0234] Optionally, the detection device 4 is used to calculate the actual size of the object space corresponding to each pixel in the historical second frame image;

[0235] Using a preset matching algorithm, the homography matrix of adjacent historical second-frame images is calculated. The homography matrix represents the magnitude of the change between adjacent historical second-frame images.

[0236] Based on the homography matrix, calculate the image displacement of the next historical second frame image relative to the previous historical second frame image in adjacent historical second frame images;

[0237] Based on the actual size of the object space corresponding to each pixel, determine the actual displacement of the second historical frame image of the next frame relative to the second historical frame image of the previous frame.

[0238] The actual displacement is accumulated to determine the cumulative mileage.

[0239] Optionally, the mileage calibration device for a vehicle provided in this embodiment of the invention further includes: a positioning device 47, used to determine the position of the vehicle in the tunnel based on the calibrated mileage of the vehicle and tunnel information, the tunnel information including: the length of the tunnel, the tunnel entrance position, the tunnel exit position, and the curvature angle of the tunnel at different locations.

[0240] This invention provides a vehicle mileage calibration device. The device acquires a first frame image of a tunnel captured by a first image acquisition device at the current time, and a second frame image of the tunnel surface captured by a second image acquisition device at the current time. Based on the second frame image at the current time and historical frame images, the mileage of the vehicle is calculated. When the first frame image at the current time is detected to contain a mileage marker, the mileage of the vehicle is calibrated based on the character information in the first frame image containing the mileage marker. Compared to existing technologies, this invention improves the accuracy of mileage calibration in tunnels by identifying character information in the first frame image containing mileage markers with high positioning accuracy and prominent image features, and then calibrating the mileage calculated based on the second frame image and historical frame images using this character information. This enhances the accuracy of vehicle mileage calibration in tunnels, thereby improving the accuracy of vehicle positioning within tunnels.

[0241] II. Application Examples. To demonstrate the inventiveness and technical value of the present invention, this section provides application examples of the technical solution on specific products or related technologies.

[0242] The calibration method provided by the present invention can be applied to a computer-readable storage medium containing a computer program that, when executed by a processor, implements the steps of the mileage calibration method for any of the above-described vehicles.

[0243] The calibration method provided by this invention can be applied to a computer program product containing instructions, which, when run on a computer, causes the computer to execute the mileage calibration method for any of the driving tools described in the above embodiments.

[0244] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0245] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0246] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0247] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for calibrating the mileage of a vehicle, characterized in that, Mileage markers are installed in areas not covered by communication networks, and the mileage markers are marked with character information. The mileage calibration method for the vehicle includes the following steps: The first image capture device captures a first frame image of an area not covered by the communication network at the current time, and the second image capture device captures a second frame image of the road surface in the area not covered by the communication network at the current time. The first image capturing device and the second image capturing device move synchronously with the vehicle. The shooting angle of the first image capturing device is between the vertical area not covered by the communication network and the horizontal area not covered by the communication network. The mileage of the vehicle is calculated based on the second frame image at the current time and the historical frame image, wherein the historical frame image is the first frame image used when the vehicle was last calibrated. When the first frame image at the current time is detected to contain the mileage marker, the character information of the first frame image containing the mileage marker is identified to obtain the identification result; When the recognition result is that the character information is not recognized, the second historical frame image of the road surface in the area not covered by the communication network is obtained from the time from the last time the mileage of the driving tool was calibrated to the current time. Based on the second historical frame image, the cumulative mileage of the vehicle is calculated; The mileage from the last calibration is summed with the preset first value to obtain the first summation result; The mileage from the last calibration is summed with the cumulative mileage to obtain a second summation result; The first summation result is compared with the second summation result to calibrate the mileage of the vehicle at the current time; The step of comparing the first summation result with the second summation result to calibrate the mileage of the vehicle at the current time includes: When the difference between the first summation result and the second summation result does not exceed the first difference threshold, the difference between the first summation result and the preset second value is determined as the mileage of the vehicle at the current time. When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time. When the recognition result is that the character information is recognized, the character information includes: the distance of the mileage marker from the starting point, and whether the difference between the distance in the historical character information and the distance in the character information at the current time exceeds a second difference threshold. The historical character information is the character information of the last mileage calibration. When the difference between the distance in the character information at the current time and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the character information at the current time and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time. When the difference between the distance in the character information at the current time and the distance in the historical character information exceeds the second difference threshold, a second historical frame image captured by the second image capturing device from the last calibration of the vehicle mileage to the current time is acquired. Calculate the cumulative mileage based on the aforementioned second historical frame image; The sum of the cumulative mileage and the distance in the historical character information is determined as the mileage of the vehicle at the current time.

2. The mileage calibration method for a vehicle according to claim 1, characterized in that, The method further includes: Detect whether the mileage marker is contained in the first frame image at the current time; When there are multiple first frame images containing the mileage marker, a target frame image is determined from the multiple first frame images. The target frame image is the first frame image whose center point is closest to the center point of the mileage marker. The mileage of the vehicle is calibrated based on the character information in the target frame image; When there are multiple first frame images containing the mileage markers, the character information of the mileage markers in each first frame image containing the mileage markers is identified to obtain a recognition result, wherein the recognition result is: whether the character information is identified; For the recognition results that identify the character information, count the number of times the character information in the recognition results is the same as the other character information; When the number of identical characters in the recognition result exceeds a preset threshold, the mileage of the vehicle at the current time is calibrated based on the number of identical characters exceeding the preset threshold.

3. The mileage calibration method for a vehicle according to any one of claims 1 or 2, characterized in that, The calculation of the cumulative mileage based on the historical second frame image includes: Calculate the actual size of the object space corresponding to each pixel in the second historical frame image; Using a preset matching algorithm, the homography matrix of adjacent historical second-frame images is calculated, and the homography matrix represents the magnitude of the change in the adjacent historical second-frame images; Based on the homography matrix, calculate the image displacement of the next historical second frame image relative to the previous historical second frame image in adjacent historical second frame images; Based on the actual size of the object space corresponding to each pixel, the actual displacement of the next historical second frame image relative to the previous historical second frame image is determined. The actual displacements are accumulated to determine the accumulated mileage.

4. The mileage calibration method for a vehicle according to claim 1, characterized in that, The method further includes: Based on the calibrated mileage of the vehicle and the tunnel information, the position of the vehicle in the tunnel is determined. The tunnel information includes: the length of the tunnel, the location of the tunnel entrance, the location of the tunnel exit, and the curvature angle of the tunnel at different locations.

5. A mileage calibration device for a vehicle, characterized in that, The mileage calibration device for the vehicle includes: The first image capturing device is used to capture an area not covered by the communication network at the current time to obtain the first frame image; The second image capturing device is used to capture a second frame image of the road surface in an area not covered by the communication network at the current time. The decision-making device is configured to connect to the first image capturing device and the second image capturing device respectively, and to acquire a first frame image of an area not covered by the communication network captured by the first image capturing device at the current time, and a second frame image of the road surface in the area not covered by the communication network captured by the second image capturing device at the current time. The mileage of the vehicle is calculated based on the second frame image at the current time and the historical frame image, wherein the historical frame image is the first frame image used when the vehicle was last calibrated. The detection device is used to identify character information of the first frame image containing the mileage marker when it detects that the first frame image at the current time contains a mileage marker, and to obtain a recognition result; When the recognition result is that the character information is not recognized, the second historical frame image of the road surface in the area not covered by the communication network is obtained from the time from the last time the mileage of the driving tool was calibrated to the current time. Based on the second historical frame image, the cumulative mileage of the vehicle is calculated; The mileage from the last calibration is summed with the preset first value to obtain the first summation result; The mileage from the last calibration is summed with the cumulative mileage to obtain a second summation result; The first summation result is compared with the second summation result to calibrate the mileage of the vehicle at the current time; The step of comparing the first summation result with the second summation result to calibrate the mileage of the vehicle at the current time includes: When the difference between the first summation result and the second summation result does not exceed the first difference threshold, the difference between the first summation result and the preset second value is determined as the mileage of the vehicle at the current time. When the difference between the first summation result and the second summation result exceeds the first difference threshold, the difference between the second summation result and the preset second value is determined as the mileage of the vehicle at the current time. When the recognition result is that the character information is recognized, the character information includes: the distance of the mileage marker from the starting point, and whether the difference between the distance in the historical character information and the distance in the character information at the current time exceeds a second difference threshold. The historical character information is the character information of the last mileage calibration. When the difference between the distance in the character information at the current time and the distance in the historical character information does not exceed the second difference threshold, the sum of the distance in the character information at the current time and the initial mileage of the vehicle is determined as the mileage of the vehicle at the current time. When the difference between the distance in the character information at the current time and the distance in the historical character information exceeds the second difference threshold, a second historical frame image captured by the second image capturing device from the last calibration of the vehicle mileage to the current time is acquired. Calculate the cumulative mileage based on the aforementioned second historical frame image; The sum of the cumulative mileage and the distance in the historical character information is determined as the mileage of the vehicle at the current time.

6. The mileage calibration device for a vehicle as described in claim 5, characterized in that, The mileage calibration device for the vehicle also includes: The recognition device is used to recognize the character information of the mileage marker in each first frame image containing the mileage marker when there are multiple first frame images containing mileage markers, and to obtain the recognition result, which is whether the character information is recognized. The positioning device is used to determine the position of a vehicle in a tunnel based on the calibrated mileage of the vehicle and tunnel information, including the tunnel length, tunnel entrance location, tunnel exit location, and tunnel curvature angle at different locations.

7. A server, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; a machine-readable storage medium stores machine-executable instructions that can be executed by the processor, wherein the processor is prompted by the machine-executable instructions to execute the mileage calibration method of any one of claims 1 to 4.

8. A computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor as the mileage calibration method of any one of claims 1 to 4.

9. A testing vehicle, characterized in that, The testing vehicle is equipped with a mileage calibration device for a driving tool as described in any one of claims 5 to 6.

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