Vehicle speed measurement method and device based on multi-focal length camera

Abstract

The present invention relates to a vehicle speed measurement method and device based on a multi-focal-segment camera, the method comprising: when a vehicle enters the field of view of the multi-focal-segment camera, using each lens of the multi-focal-segment camera to capture and identify the license plate of the vehicle; obtaining the coordinates of the first target position and the coordinates of the second target position captured by the vehicle, and converting the first target position coordinates and the second target position coordinates into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position; using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position, calculating the distance between the first target position and the second target position; using the distance between the first target position and the second target position, calculating the speed of the vehicle. The technical solution provided by the present application realizes the measurement of the speed of a vehicle traveling at any speed, and improves the accuracy of speed measurement.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle speed measurement, and in particular relates to a vehicle speed measurement method and device based on a multi-focal-segment camera. Background Art

[0002] The current method of measuring vehicle speed through video usually uses a special camera set up above the road to capture passing vehicles. During the vehicle's driving process, when the vehicle appears in the camera screen twice or more and is captured by the camera, the camera obtains the movement time based on the time difference between the two captures. Based on the position of the vehicle at the time of the two captures, the running distance of the vehicle between the two captures is calculated, and the vehicle speed can be calculated through v=s / t.

[0003] However, because existing dedicated cameras are usually monocular cameras, their vertical shooting distance is limited, generally 10-30 meters. When the vehicle speed is very high, the camera cannot capture more than two photos, resulting in the inability to measure speed and the problem of speed measurement omission. According to actual research, when the vehicle speed is higher than 180km / h, the existing technology cannot complete the speed measurement. Summary of the invention

[0004] In view of this, an object of the present invention is to overcome the deficiencies of the prior art and to provide a vehicle speed measurement method and device based on a multi-focal length camera to solve the problem of speed measurement omission when the vehicle speed is measured too fast in the prior art.

[0005] According to a first aspect of an embodiment of the present application, a vehicle speed measurement method based on a multi-focal-segment camera is provided, the method comprising:

[0006] When a vehicle enters the field of view of the multi-focal length camera, each lens of the multi-focal length camera is used to capture the vehicle and recognize the license plate;

[0007] Acquire the coordinates of the first target position and the coordinates of the second target position captured by the vehicle, and convert the first target position coordinates and the second target position coordinates into longitude and latitude coordinates respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position;

[0008] Calculating the distance between the first target position and the second target position using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position;

[0009] Calculating the speed of the vehicle using the distance between the first target position and the second target position;

[0010] The coordinates of the first target position are the coordinates of the position where the vehicle was captured for the first time, and the coordinates of the second target position are the coordinates of the position where the vehicle was captured for the last time.

[0011] Further, the obtaining of the coordinates of the first target position and the second target position of the vehicle captured includes:

[0012] When the non-shortest focal lens in the multi-focal length camera captures the coordinates of the first target position and the coordinates of the second target position, the coordinates of the first target position and the coordinates of the second target position are converted into coordinates within the video screen of the shortest focal lens in the multi-focal length camera.

[0013] Furthermore, the acquiring the coordinates of the first target position and the second target position of the vehicle captured by the camera further includes:

[0014] According to the timestamp when the vehicle is captured by the multi-focal-segment camera, the position at which the vehicle is first captured and the position at which the vehicle is last captured are determined, and the coordinates of the target position at which the vehicle is first captured and the coordinates of the position at which the vehicle is last captured, that is, the coordinates of the first target position and the coordinates of the second target position at which the vehicle is captured, are obtained.

[0015] Furthermore, the multi-focal-length camera uses the PTP protocol to synchronize the time of a clock synchronization module in the multi-focal-length camera to millisecond level.

[0016] Further, calculating the distance between the first target position and the second target position by using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position includes:

[0017] Based on the Haversine formula, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0018] Further, the calculating the speed of the vehicle by using the distance between the first target position and the second target position includes:

[0019] The speed V of the vehicle is calculated as follows:

[0020] V=S / T

[0021] In the above formula, S is the distance between the first target position and the second target position, and T is the difference between the timestamp when the vehicle passes the first target position and the timestamp when the vehicle passes the second target position.

[0022] Furthermore, the method further comprises:

[0023] Capturing a first target video picture and a second target video picture;

[0024] Registering the first target video picture with the second target video picture to determine a position of the first target video picture within the second target video picture;

[0025] The first target video picture is a video picture shot by a non-shortest focal lens in a multi-focal length camera, and the second target video picture is a video picture shot by a shortest focal lens in the multi-focal length camera.

[0026] Furthermore, the method further comprises:

[0027] A plurality of points are selected on the highway in the second target video screen, and the coordinates and longitude and latitude of each of the points are obtained to perform a homography transformation between the coordinates of each of the points and the longitude and latitude of each of the points.

[0028] According to a second aspect of an embodiment of the present application, a vehicle speed measuring device based on a multi-focal-segment camera is provided, the device comprising:

[0029] The capture module is used to capture and recognize the license plate of the vehicle using each lens of the multi-focal-length camera when the vehicle enters the field of view of the multi-focal-length camera;

[0030] A coordinate conversion module, used to obtain the coordinates of the first target position and the coordinates of the second target position of the vehicle captured, and convert the first target position coordinates and the second target position coordinates into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position;

[0031] A first calculation module, used to calculate the distance between the first target position and the second target position by using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position;

[0032] a second calculation module, configured to calculate the speed of the vehicle using the distance between the first target position and the second target position;

[0033] The coordinates of the first target position are the coordinates of the position where the vehicle was captured for the first time, and the coordinates of the second target position are the coordinates of the position where the vehicle was captured for the last time.

[0034] Furthermore, the multi-focal-length camera uses the PTP protocol to synchronize the time of a clock synchronization module in the multi-focal-length camera to millisecond level.

[0035] The present invention adopts the above technical scheme, and the beneficial effects that can be achieved include: by using each lens of the multi-focal-segment camera to capture and recognize the vehicle license plate, the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured are obtained, and the coordinates of the first target position and the second target position are respectively converted into longitude and latitude coordinates to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position, and the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position, and the speed of the vehicle is calculated using the distance between the first target position and the second target position, thereby realizing the measurement of the speed of the vehicle traveling at any speed, improving the accuracy of the speed measurement, and avoiding the occurrence of speed measurement omissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 is a flow chart of a vehicle speed measurement method based on a multi-focal-length camera according to an exemplary embodiment;

[0038] Figure 2 is a simulation diagram of the field of view of a multi-focal-length camera according to an exemplary embodiment;

[0039] Figure 3 is a schematic diagram showing the coverage of each lens of a multi-focal-length camera according to an exemplary embodiment;

[0040] Figure 4 is a flow chart of a vehicle speed measurement method based on a multi-focal-length camera according to an exemplary embodiment;

[0041] Figure 5 The present invention is a structural block diagram of a vehicle speed measuring device based on a multi-focal-length camera according to an exemplary embodiment. DETAILED DESCRIPTION

[0042] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0043] Figure 1is a flow chart of a vehicle speed measurement method based on a multi-focal-length camera according to an exemplary embodiment. Figure 1 As shown, the method can be but is not limited to being used in a terminal, and includes the following steps:

[0044] Step 101: When a vehicle enters the field of view of the multi-focal length camera, each lens of the multi-focal length camera is used to capture the vehicle and recognize the license plate;

[0045] Step 102: obtaining the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured, and converting the coordinates of the first target position and the second target position into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position;

[0046] Step 103: Calculate the distance between the first target position and the second target position using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position;

[0047] Step 104: Calculate the speed of the vehicle using the distance between the first target position and the second target position;

[0048] The coordinates of the first target position are the coordinates of the position where the vehicle was first captured, and the coordinates of the second target position are the coordinates of the position where the vehicle was last captured.

[0049] It should be noted that the method of “capturing a vehicle and recognizing a license plate” involved in the embodiments of the present invention is well known to those skilled in the art, and therefore, its specific implementation method will not be described in detail.

[0050] In some embodiments, since the multi-focal length camera is a beyond-visual-range, ultra-high-definition, full-target-coverage integrated monitoring array computing camera, it can realize the shooting and monitoring of narrow and long passage areas such as roads, railways, tunnels, bridges, and corridors. Therefore, a vehicle detection module and a license plate recognition module can be set in the multi-focal length camera to respectively capture vehicles and recognize license plates.

[0051] For example, the MFC606 multi-focal length camera can cover 23-250 meters of highway and perform license plate recognition on all vehicles within this distance. Therefore, in a complete narrow channel, the camera's multiple lenses can ensure that vehicles are captured and identified multiple times.

[0052] A vehicle speed measurement method based on a multi-focal-segment camera is provided in an embodiment of the present invention. Each lens of the multi-focal-segment camera is used to capture and recognize a vehicle license plate, so as to obtain the coordinates of a first target position and a second target position of the captured vehicle, and convert the coordinates of the first target position and the second target position into longitude and latitude coordinates respectively, so as to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position. The longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position are used to calculate the distance between the first target position and the second target position, and the speed of the vehicle is calculated using the distance between the first target position and the second target position, so as to realize the measurement of the speed of the vehicle traveling at any speed, improve the accuracy of the speed measurement, and avoid the occurrence of speed measurement omissions.

[0053] Further, in step 102, obtaining the coordinates of the first target position and the second target position of the vehicle captured includes:

[0054] When the non-shortest focal lens in the multi-focal length camera captures the coordinates of the first target position and the coordinates of the second target position, the coordinates of the first target position and the second target position are converted into coordinates in the video screen of the shortest focal lens in the multi-focal length camera.

[0055] In some embodiments, the model of the multi-focal length camera may be, but is not limited to, an MFC606 camera. Figure 2 As shown in the figure, the camera field of view of MFC606 is simulated. Assuming the camera is installed at a height of 5 meters and the road width is 15 meters, the camera can perform full coverage license plate recognition on the road from the nearest 23 meters to the farthest 250 meters. Figure 3 As shown, the coverage of each lens is as follows:

[0056] The 12mm focal length lens has a minimum coverage distance of 13 meters, and can cover a 15-meter wide road starting from 23 meters;

[0057] The 16mm focal length lens has a minimum coverage distance of 18 meters, and can cover a 15-meter wide road starting from 31 meters;

[0058] The 25mm focal length lens has a minimum coverage distance of 29 meters, and can cover a 15-meter wide road from 49 meters;

[0059] The 35mm focal length lens has a minimum coverage distance of 40 meters, and can cover a 15-meter wide road starting from 68 meters;

[0060] The 50mm focal length lens has a minimum coverage distance of 58 meters, and can cover a 15-meter wide road from 97 meters;

[0061] The 75mm focal length lens can cover the shortest distance of 87 meters and can cover a 15-meter wide road starting from 146 meters.

[0062] Furthermore, the step 102 of acquiring the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured also includes:

[0063] According to the timestamp when the vehicle is captured by the multi-focal length camera, the position where the vehicle is first captured and the position where the vehicle is last captured are determined, and the coordinates of the target position where the vehicle is first captured and the coordinates of the position where the vehicle is last captured, that is, the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured, are obtained.

[0064] Specifically, the multi-focal length camera uses the PTP protocol to synchronize the time of the clock synchronization module in the multi-focal length camera to the millisecond level.

[0065] Further, in step 103, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position, including:

[0066] Based on the Haversine formula, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0067] In some embodiments, the distance between the first target position and the second target position may be calculated based on, but not limited to, the Great-circle distance formula using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0068] Further, in step 104, the speed of the vehicle is calculated using the distance between the first target position and the second target position, including:

[0069] Calculate the vehicle's speed V as follows:

[0070] V=S / T

[0071] In the above formula, S is the distance between the first target position and the second target position, and T is the difference between the timestamp when the vehicle passes the first target position and the timestamp when the vehicle passes the second target position.

[0072] Furthermore, the method further comprises:

[0073] Capturing a first target video picture and a second target video picture;

[0074] Registering the first target video picture with the second target video picture to determine the position of the first target video picture within the second target video picture;

[0075] The first target video picture is a video picture shot by a non-shortest focal lens in the multi-focal length camera, and the second target video picture is a video picture shot by the shortest focal lens in the multi-focal length camera.

[0076] It is understandable that the above steps of "aligning the first target video image with the second target video image" and "obtaining the coordinates and longitude and latitude of each point" should be completed before capturing the vehicle, which is equivalent to a calibration process. For example, taking the MFC606 camera as an example, there are 6 lenses, of which 12mm is the shortest focal lens, and the video images of other non-shortest focal lenses are all within the video image taken by this shortest focal lens; 6 lenses correspond to 6 video streams, and the corresponding video streams can be obtained respectively.

[0077] Furthermore, the method further comprises:

[0078] A number of points are selected on the road in the second target video screen, and the coordinates and longitude and latitude of each point are obtained to perform a homography transformation between the coordinates of each point and the longitude and latitude of each point.

[0079] It can be understood that the more points are selected on the road within the shortest focal length lens video frame, the more accurate the speed measurement precision is.

[0080] In some optional embodiments, when the camera is set up on site to shoot a highway, points can be selected in proportion to the direction of the highway according to the position of the highway in the video screen, or points can be selected according to specific reference objects on the highway (such as signs on the highway). After these points are determined, the coordinates on the video screen are also determined, and the coordinates of these points on the video screen are A. At the same time, the longitude and latitude information B of these points are obtained (all points correspond to an actual position, and the longitude and latitude of the position can be directly measured), and A and B correspond one to one. Record the corresponding information.

[0081] To further illustrate the vehicle speed measurement method based on a multi-focal length camera provided in the above embodiment, the embodiment of the present invention provides a specific example, such as Figure 4 As shown, the following steps are included:

[0082] Step 201: Capture a first target video image and a second target video image;

[0083] The first target video picture is a video picture taken by a non-shortest focal lens in the multi-focal length camera, and the second target video picture is a video picture taken by the shortest focal lens in the multi-focal length camera;

[0084] Step 202: registering the first target video picture with the second target video picture to determine the position of the first target video picture within the second target video picture;

[0085] Step 203: Select a number of points on the road in the second target video frame, and obtain the coordinates and longitude and latitude of each point to perform a homography transformation between the coordinates of each point and the longitude and latitude of each point;

[0086] Step 204: when the vehicle enters the field of view of the multi-focal-length camera, each lens of the multi-focal-length camera is used to capture the vehicle and recognize the license plate;

[0087] Step 205: Obtain the coordinates (x0, y0) of the first target position and the coordinates (x1, y1) of the second target position where the vehicle is captured, and convert the coordinates of the first target position and the second target position into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates (x2, y2) of the first target position and the longitude and latitude coordinates (x3, y3) of the second target position;

[0088] The coordinates of the first target position are the coordinates of the position where the vehicle was first captured, and the coordinates of the second target position are the coordinates of the position where the vehicle was last captured;

[0089] Step 206: Calculate the distance between the first target position and the second target position using the longitude and latitude coordinates (x2, y2) of the first target position and the longitude and latitude coordinates (x3, y3) of the second target position;

[0090] Step 207: Calculate the speed of the vehicle using the distance between the first target position and the second target position.

[0091] Furthermore, in step 205, obtaining the coordinates of the first target position and the second target position of the vehicle captured includes:

[0092] When the non-shortest focal lens in the multi-focal length camera captures the coordinates of the first target position and the coordinates of the second target position, the coordinates of the first target position and the second target position are converted into coordinates in the video screen of the shortest focal lens in the multi-focal length camera.

[0093] Further, in step 205, obtaining the coordinates of the first target position and the second target position of the vehicle captured includes:

[0094] According to the timestamp when the vehicle is captured by the multi-focal length camera, the position where the vehicle is first captured and the position where the vehicle is last captured are determined, and the coordinates (x0, y0) of the target position where the vehicle is first captured and the coordinates (x1, y1) of the position where the vehicle is last captured are obtained, that is, the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured.

[0095] Specifically, the multi-focal length camera uses the PTP protocol to synchronize the time of the clock synchronization module in the multi-focal length camera to the millisecond level.

[0096] Further, in step 206, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position, including:

[0097] Based on the Haversine formula, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0098] In some embodiments, the distance between the first target position and the second target position may be calculated based on, but not limited to, the Great-circle distance formula using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0099] Further, in step 207, the speed of the vehicle is calculated using the distance between the first target position and the second target position, including:

[0100] Calculate the vehicle's speed V as follows:

[0101] V=S / T

[0102] In the above formula, S is the distance between the first target position and the second target position, and T is the difference between the timestamp when the vehicle passes the first target position and the timestamp when the vehicle passes the second target position.

[0103] A vehicle speed measurement method based on a multi-focal-segment camera is provided in an embodiment of the present invention. Each lens of the multi-focal-segment camera is used to capture and recognize a vehicle license plate, so as to obtain the coordinates of a first target position and a second target position of the captured vehicle, and convert the coordinates of the first target position and the second target position into longitude and latitude coordinates respectively, so as to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position. The longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position are used to calculate the distance between the first target position and the second target position, and the speed of the vehicle is calculated using the distance between the first target position and the second target position, so as to realize the measurement of the speed of the vehicle traveling at any speed, improve the accuracy of the speed measurement, and avoid the occurrence of speed measurement omissions.

[0104] In order to cooperate with the above-mentioned vehicle speed measurement method based on a multi-focal length camera, an embodiment of the present invention provides a vehicle speed measurement device based on a multi-focal length camera, referring to Figure 5 , the device comprises:

[0105] The capture module is used to capture and recognize the license plate of the vehicle using each lens of the multi-focal-length camera when the vehicle enters the field of view of the multi-focal-length camera;

[0106] A coordinate conversion module is used to obtain the coordinates of the first target position and the coordinates of the second target position of the vehicle captured, and convert the coordinates of the first target position and the second target position into longitude and latitude coordinates respectively, so as to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position;

[0107] A first calculation module, used to calculate the distance between the first target position and the second target position using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position;

[0108] A second calculation module is used to calculate the speed of the vehicle using the distance between the first target position and the second target position;

[0109] The coordinates of the first target position are the coordinates of the position where the vehicle was first captured, and the coordinates of the second target position are the coordinates of the position where the vehicle was last captured.

[0110] Furthermore, the capture module is specifically used for:

[0111] When the non-shortest focal lens in the multi-focal length camera captures the coordinates of the first target position and the coordinates of the second target position, the coordinates of the first target position and the second target position are converted into coordinates in the video screen of the shortest focal lens in the multi-focal length camera.

[0112] Furthermore, the coordinate conversion module is specifically used for:

[0113] According to the timestamp when the vehicle is captured by the multi-focal length camera, the position where the vehicle is first captured and the position where the vehicle is last captured are determined, and the coordinates of the target position where the vehicle is first captured and the coordinates of the position where the vehicle is last captured, that is, the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured, are obtained.

[0114] Specifically, the multi-focal length camera uses the PTP protocol to synchronize the time of the clock synchronization module in the multi-focal length camera to the millisecond level.

[0115] Furthermore, the first computing module is specifically used for:

[0116] Based on the Haversine formula, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

[0117] Furthermore, the second computing module is specifically used for:

[0118] Calculate the vehicle's speed V as follows:

[0119] V=S / T

[0120] In the above formula, S is the distance between the first target position and the second target position, and T is the difference between the timestamp when the vehicle passes the first target position and the timestamp when the vehicle passes the second target position.

[0121] Furthermore, the device also includes:

[0122] A collection module, used for collecting the first target video picture and the second target video picture;

[0123] A registration module, used for registering the first target video picture with the second target video picture to determine the position of the first target video picture within the second target video picture;

[0124] The first target video picture is a video picture shot by a non-shortest focal lens in the multi-focal length camera, and the second target video picture is a video picture shot by the shortest focal lens in the multi-focal length camera.

[0125] Furthermore, the device also includes:

[0126] The acquisition module is used to select a number of points on the road in the second target video screen and obtain the coordinates and longitude and latitude of each point to perform a homography transformation between the coordinates of each point and the longitude and latitude of each point.

[0127] A vehicle speed measuring device based on a multi-focal-segment camera is provided in an embodiment of the present invention. A capture module uses each lens of the multi-focal-segment camera to capture a vehicle and recognize a license plate. A coordinate conversion module obtains the coordinates of a first target position and a second target position where the vehicle is captured, and converts the coordinates of the first target position and the second target position into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position. A first calculation module uses the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position to calculate the distance between the first target position and the second target position. A second calculation module uses the distance between the first target position and the second target position to calculate the speed of the vehicle, thereby realizing the measurement of the speed of the vehicle traveling at any speed, improving the accuracy of the speed measurement, and avoiding the occurrence of speed measurement omissions.

[0128] An embodiment of the present invention further provides a readable storage medium having an executable program stored thereon, and when the executable program is executed by a processor, the steps in the above-mentioned vehicle speed measurement method based on a multi-focal-length camera are implemented.

[0129] It can be understood that the device embodiment provided above corresponds to the method embodiment described above, and the corresponding specific contents can be referenced to each other and will not be repeated here.

[0130] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0131] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of the processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0132] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction method, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0133] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0134] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A vehicle speed measurement method based on a multi-focal-length camera, characterized in that: The method comprises: When a vehicle enters the field of view of the multi-focal length camera, each lens of the multi-focal length camera is used to capture the vehicle and recognize the license plate; Acquire the coordinates of the first target position and the coordinates of the second target position captured by the vehicle, and convert the first target position coordinates and the second target position coordinates into longitude and latitude coordinates respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position; Calculating the distance between the first target position and the second target position using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position; Calculating the speed of the vehicle using the distance between the first target position and the second target position; Wherein, the coordinates of the first target position are the coordinates of the position where the vehicle was first captured, and the coordinates of the second target position are the coordinates of the position where the vehicle was last captured; Also includes: Capturing a first target video picture and a second target video picture; Registering the first target video picture with the second target video picture to determine a position of the first target video picture within the second target video picture; The first target video picture is a video picture shot by a non-shortest focal lens in a multi-focal length camera, and the second target video picture is a video picture shot by a shortest focal lens in the multi-focal length camera.

2. The method according to claim 1, characterized in that The acquiring the coordinates of the first target position and the coordinates of the second target position where the vehicle is captured also includes: When the non-shortest focal lens in the multi-focal length camera captures the coordinates of the first target position and the coordinates of the second target position, the coordinates of the first target position and the coordinates of the second target position are converted into coordinates within the video screen of the shortest focal lens in the multi-focal length camera.

3. The method according to claim 1, characterized in that The obtaining of the coordinates of the first target position and the coordinates of the second target position of the vehicle captured includes: According to the timestamp when the vehicle is captured by the multi-focal-segment camera, the position at which the vehicle is first captured and the position at which the vehicle is last captured are determined, and the coordinates of the target position at which the vehicle is first captured and the coordinates of the position at which the vehicle is last captured, that is, the coordinates of the first target position and the coordinates of the second target position at which the vehicle is captured, are obtained.

4. The method according to claim 3, characterized in that The multi-focal-length camera uses the PTP protocol to synchronize the time of a clock synchronization module in the multi-focal-length camera at the millisecond level.

5. The method according to claim 1, characterized in that: The calculating the distance between the first target position and the second target position by using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position includes: Based on the Haversine formula, the distance between the first target position and the second target position is calculated using the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position.

6. The method according to claim 1, characterized in that The calculating the speed of the vehicle by using the distance between the first target position and the second target position comprises: The speed V of the vehicle is calculated as follows: V=S / T In the above formula, S is the distance between the first target position and the second target position, and T is the difference between the timestamp when the vehicle passes the first target position and the timestamp when the vehicle passes the second target position.

7. The method according to claim 1, characterized in that The method further comprises: A plurality of points are selected on the highway in the second target video screen, and the coordinates and longitude and latitude of each of the points are obtained to perform a homography transformation between the coordinates of each of the points and the longitude and latitude of each of the points.

8. A vehicle speed measuring device based on a multi-focal-length camera, characterized in that: The device comprises: A capture module is used to capture a first target video image and a second target video image; align the first target video image with the second target video image to determine the position of the first target video image within the second target video image; wherein the first target video image is a video image taken by a non-shortest focal lens in a multi-focal-segment camera, and the second target video image is a video image taken by a shortest focal lens in the multi-focal-segment camera; when a vehicle enters the field of view of the multi-focal-segment camera, each lens of the multi-focal-segment camera is used to capture the vehicle and recognize the license plate; A coordinate conversion module, used to obtain the coordinates of the first target position and the coordinates of the second target position of the vehicle captured, and convert the first target position coordinates and the second target position coordinates into longitude and latitude coordinates, respectively, to obtain the longitude and latitude coordinates of the first target position and the longitude and latitude coordinates of the second target position; A first calculation module, used to calculate the distance between the first target position and the second target position by using the latitude and longitude coordinates of the first target position and the latitude and longitude coordinates of the second target position; a second calculation module, configured to calculate the speed of the vehicle using the distance between the first target position and the second target position; The coordinates of the first target position are the coordinates of the position where the vehicle was captured for the first time, and the coordinates of the second target position are the coordinates of the position where the vehicle was captured for the last time.

9. The device according to claim 8, characterized in that The multi-focal-length camera uses the PTP protocol to synchronize the time of a clock synchronization module in the multi-focal-length camera at the millisecond level.

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