Bridge linear image measurement method based on unmanned aerial vehicle and related device

Abstract

The embodiment of the invention relates to the technical field of data processing and bridge linear measurement, and provides a bridge linear image measurement method based on an unmanned aerial vehicle and a related device, and the method comprises the steps: setting a mark point and pasting a mark plate for a to-be-measured bridge; setting an unmanned aerial vehicle shooting path, and performing image shooting to obtain a first image set; correcting the first image to obtain a second image set; calculating and correcting a second image pixel size; identifying and calculating delta x and delta y between adjacent mark points; and calculating the measurement coordinate value of each mark point. According to the method and the related device, the linear coordinate of the to-be-measured bridge can be calculated according to the image data acquired by the unmanned aerial vehicle, and the measurement efficiency is improved while the measurement precision is ensured.

Description

Technical Field

[0001] The present application relates to the technical fields of data processing and bridge linear measurement, and in particular to a bridge linear image measurement method based on an unmanned aerial vehicle and related devices. Background Art

[0002] The existing scheme for linear measurement of bridge structures usually uses optical measuring instruments or Beidou and GPS satellite positioning systems. Optical measuring instruments use the principle of linear propagation of light, angle measurement and laser ranging technology to calculate coordinates and obtain the linear coordinates of the measured bridge structure. However, since optical instrument measurement requires manual operation, the degree of automation is low and the workload is large, the efficiency of measurement is low. Beidou and GPS satellite positioning systems have low measurement accuracy and are expensive. Summary of the invention

[0003] The embodiment of the present application provides a bridge linear image measurement method and related devices based on a drone, which can calculate the linear coordinates of the bridge to be measured according to the image data collected by the drone, thereby improving the measurement efficiency while ensuring the measurement accuracy.

[0004] A first aspect of an embodiment of the present application provides a bridge linear image measurement method based on a drone, which is applied to a drone. The method includes:

[0005] Set up marking points and affix marking plates;

[0006] Setting a shooting path for the drone and shooting images to obtain a first image set;

[0007] Correcting the first image to obtain a second image set;

[0008] Calculating and correcting the second image pixel size;

[0009] Identify and calculate Δx and Δy between adjacent markers;

[0010] Calculate the measured coordinates of each marked point.

[0011] In this example, the marking points and marking boards are obtained, the drone shooting path is set, images are taken to obtain a first image set, the first image is corrected to obtain a second image set, the pixel size of the second image is calculated and corrected, the Δx and Δy between adjacent marking points are identified and calculated, and the measurement coordinate value of each marking point is calculated. Therefore, the linear coordinates of the bridge to be measured can be calculated based on the image data collected by the drone, which improves the measurement efficiency while ensuring the measurement accuracy.

[0012] A second aspect of an embodiment of the present application provides a bridge linear image measurement device based on a drone, which is applied to a drone, and the device includes:

[0013] The acquisition unit is used to set the marking point and paste the marking plate; set the drone shooting path, and shoot the image to obtain the first image set;

[0014] The processing unit is used to correct the first image to obtain a second image set; calculate and correct the pixel size of the second image; identify and calculate Δx and Δy between adjacent marking points; and calculate the measured coordinate value of each marking point.

[0015] A third aspect of an embodiment of the present application provides a terminal, comprising a processor, an input device, an output device and a memory, wherein the processor, input device, output device and memory are interconnected, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the step instructions in the first aspect of the embodiment of the present application.

[0016] The fourth aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute part or all of the steps described in the first aspect of the embodiments of the present application.

[0017] A fifth aspect of the embodiments of the present application provides a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to execute some or all of the steps described in the first aspect of the embodiments of the present application. The computer program product may be a software installation package. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic flow chart of a bridge linear image measurement method based on a drone is provided for an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the structure of a terminal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0023] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0024] In order to better understand the bridge linear image measurement method based on drone provided in the embodiment of the present application, the existing bridge linear image measurement is briefly introduced below. In the existing scheme, optical measuring instruments or Beidou and GPS satellite positioning systems are usually used. Optical measuring instruments use the principle of linear propagation of light, angle measurement and laser ranging technology to calculate coordinates and obtain the linear coordinates of the measured bridge structure. However, since optical instrument measurement requires manual operation, the degree of automation is low and the workload is large, resulting in low efficiency during measurement. Beidou and GPS satellite positioning systems have low measurement accuracy and are expensive.

[0025] In order to solve the above technical problems, an embodiment of the present application provides a bridge linear image measurement method based on a drone, which can calculate the linear coordinates of the bridge to be measured according to the image data collected by the drone, thereby improving the measurement efficiency while ensuring the measurement accuracy.

[0026] In this example, first, marking points are set and marking plates are pasted, and then the drone shooting path is set, and the shooting path information of the drone for the bridge to be measured is obtained. The bridge to be measured is imaged according to the shooting path information to obtain a first image set, and a shooting distance set and a shooting angle set are extracted from the shooting path information. The corresponding first image is corrected according to the shooting distance in the shooting distance set and the shooting angle in the shooting angle set to obtain a second image set. The coordinate difference of adjacent marking points is identified and calculated according to the second image in the second image set, and the linear coordinates of each marking point of the bridge to be measured are calculated according to the coordinate difference of the adjacent marking points. Therefore, the linear coordinates of the bridge to be measured can be calculated according to the image data collected by the drone, which improves the measurement efficiency while ensuring the measurement accuracy.

[0027] In a specific implementation, the present application also provides a bridge linear image measurement method based on a drone, as follows:

[0028] 1. Preparation

[0029] S11. Set marking points and paste marking plates.

[0030] Specifically, a point that can represent the linear change of the measured bridge is selected as a marking point, and a marking point with known coordinates is selected as a reference marking point (x0, y0).

[0031] S12. Select a marking plate with a known calibrated size and stick it on the marking point.

[0032] 2. Drone photography

[0033] Specifically, the method includes setting a shooting path of the drone and shooting images to obtain a first image set.

[0034] S21, setting a drone measurement shooting path. The drone shooting path starts from the reference mark point, shoots all the mark points twice in the forward and return journeys, and finally returns to the reference mark point;

[0035] S22, taking photos. Each photo in the first image set has at least two marking points, and two adjacent photos must contain the same marking point, and the shooting distance L and shooting angle θ of each photo are recorded.

[0036] S23. Starting from the reference mark point, number each photo in the order of forward and return shooting to obtain a first image set.

[0037] 3. Image Correction

[0038] S31, correcting each first image slice in the first image set in a numerical order according to the shooting distance L and the shooting angle θ, and restoring each photo to an image shot in an orthogonal state, to obtain a second image set;

[0039] The image can be corrected using the method described in the invention patent application "Image correction method based on camera posture change" (application number 202410162550.7).

[0040] 4. Calculate and correct pixel size

[0041] S41, using the camera parameters and the shooting distance L to calculate the pixel size of the second image, and using the following formula to calculate the pixel size:

[0042]

[0043] Where: η represents the single-side size of the pixel, in mm; B represents the orthogonal shooting distance, in mm; f represents the focal length of the lens, in mm; S c Indicates the size of the imaging device in mm 2 ; R I Indicates the camera's photo resolution.

[0044] S42. The number of pixels n on one side of the sign is extracted through image processing. Based on the known size b of one side of the sign, the size of one side of the pixel is calculated using the formula η, = b / n.

[0045] S43, taking the average value of the pixel unilateral sizes η and η′ calculated by the two methods as the final pixel unilateral size correction value η0, so as to complete the calculation and correction of the pixel size of the second image.

[0046] 5. Identify and calculate Δx and Δy between adjacent markers

[0047] Take the example of having only two markers per photo.

[0048] S51, starting from the reference mark point and ending at the last mark point according to the number of the photos taken in the previous trip, sequentially identifying the positions between adjacent mark points and in:

[0049]

[0050] J is the number of pixels in the X-axis direction between adjacent marking points, K is the number of pixels in the Y-axis direction between adjacent marking points, and η0 is the final correction value of the pixel unilateral size of the photo.

[0051] S52, starting from the last mark point and ending at the reference mark point according to the number of the return photo, sequentially identify the spaces between adjacent mark points and in:

[0052]

[0053] J is the number of pixels in the X-axis direction between adjacent marking points, K is the number of pixels in the Y-axis direction between adjacent marking points, and η0 is the final correction value of the pixel unilateral size of the photo.

[0054] 6. Error processing and calculation of measurement coordinates of each marking point

[0055] S61, Closure error processing

[0056]

[0057] Through forward and reverse observation, we can get the forward and reverse of X axis. And Y axis direction to and from Theoretically, they should be equal in magnitude and opposite in sign, that is, f x =0 and f y = 0. However, due to the influence of measurement error, there is a difference between the two, which is called the closure error.

[0058] Since the forward and reverse measurements are symmetrical in terms of the layout of marking points, the difference in coordinates of adjacent marking points, and the measurement conditions, the arithmetic mean method can be used according to the principle of closure difference distribution and the principle of calculation convenience. The Δx between adjacent marking points is i and Δy i Calculated using the following formula:

[0059]

[0060] S62, calculate the measurement coordinates of each marking point

[0061] The measured coordinates of each marker point are calculated using the following formula:

[0062] x i =x0+Δx1+···+Δx i ,y i =y0+Δy1+···+Δy i .

[0063] x i is the horizontal coordinate of the i-th marking point, y i is the ordinate of the i-th marked point.

[0064] In actual operation, steps 2 to 6 can be repeated to obtain multiple sets of measurement values ​​(x i ,y i ), and then find the average value in order to obtain a measurement result that is closer to the true value.

[0065] In another specific embodiment, another method for measuring bridge linear images based on a drone is provided, which is applied to a drone and includes:

[0066] A1. Set marking points and paste marking plates;

[0067] A2. Setting a shooting path of the drone to shoot images to obtain a first image set;

[0068] A3, correcting the first image to obtain a second image set;

[0069] A4, calculating and correcting the pixel size of the second image;

[0070] A5, identify and calculate Δx and Δy between adjacent marking points;

[0071] A6. Calculate the measured coordinate values ​​of each marked point.

[0072] The steps of setting the marking points and pasting the marking plates include:

[0073] Setting a marking point at a position that can represent the linear change of the bridge to be measured, selecting a marking plate with a known calibration size, and pasting the marking plate at the marking point;

[0074] Select a marker with known coordinates as the reference marker (x0, y0).

[0075] Specifically, the step of setting a drone shooting path and shooting images to obtain a first image set includes:

[0076] The drone shooting path starts from the reference mark point, shoots all the mark points twice in the forward and return journeys, and finally returns to the reference mark point;

[0077] Each photo must contain at least two marking points, and two adjacent photos must contain the same marking point. The photos are numbered in sequence according to the shooting path, and the shooting distance L and shooting angle θ of each photo are recorded.

[0078] Specifically, the correcting the first image to obtain a second image set includes:

[0079] Correct the photos according to the shooting distance L and the shooting angle θ, and restore each photo to an image shot in an orthogonal state to obtain a second image set;

[0080] Specifically, the calculating and correcting the pixel size of the second image includes:

[0081] The pixel size is calculated according to the camera parameters and the shooting distance L, and the pixel size is corrected according to the marker of the known calibrated size.

[0082] Specifically, the identifying and calculating Δx and Δy between adjacent marking points includes:

[0083] According to the number of the photos taken in the previous trip, starting from the reference mark point and ending at the last mark point, identify the distance between adjacent mark points in sequence. and According to the number of the photos taken on the return trip, starting from the last mark point and ending at the reference mark point, identify the distance between adjacent mark points in sequence. and

[0084] Δx between adjacent marking points i and Δy i Calculated using the following formula:

[0085]

[0086] Specifically, the calculation of the measured coordinate values ​​of each marking point includes:

[0087] The measured coordinates of each marker point are calculated using the following formula:

[0088] x i =x0+Δx1+···+Δx i ,y i =y0+Δy1+···+Δy i .

[0089] For the above embodiments, please refer to Figure 2 , Figure 2 A schematic diagram of the structure of a terminal provided in an embodiment of the present application, as shown in the figure, includes a processor, an input device, an output device and a memory, the processor, the input device, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and the program includes instructions for executing the following steps;

[0090] Set up marking points and affix marking plates;

[0091] Setting a shooting path for the drone and shooting images to obtain a first image set;

[0092] Correcting the first image to obtain a second image set;

[0093] Calculating and correcting the second image pixel size;

[0094] Identify and calculate Δx and Δy between adjacent markers;

[0095] Calculate the measured coordinates of each marked point.

[0096] The above mainly introduces the scheme of the embodiment of the present application from the perspective of the execution process on the method side. It is understandable that in order to realize the above functions, the terminal includes a hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the units and algorithm steps of each example described in the embodiments provided herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0097] The embodiment of the present application can divide the terminal into functional units according to the above method example. For example, each functional unit can be divided according to each function, or two or more functions can be integrated into one processing unit. The above integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0098] An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any one of the drone-based bridge linear image measurement methods recorded in the above method embodiments.

[0099] An embodiment of the present application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program enables a computer to execute part or all of the steps of any one of the drone-based bridge linear image measurement methods recorded in the above method embodiments.

[0100] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0101] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0103] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0104] In addition, the functional units in the various embodiments of the application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware or in the form of software program modules.

[0105] If the integrated unit is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, disk or optical disk and other media that can store program codes.

[0106] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which can include: a flash drive, a read-only memory, a random access memory, a magnetic disk or an optical disk, etc.

[0107] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A bridge linear image measurement method based on drone, characterized in that: Applied to a drone, the method comprises: Set up marking points and affix marking plates; Setting a shooting path for the drone and shooting images to obtain a first image set; Correcting the first image to obtain a second image set; Calculating and correcting the second image pixel size; Identify and calculate Δx and Δy between adjacent markers; Calculate the measured coordinates of each marked point.

2. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The step of setting the marking points and pasting the marking plates comprises: Setting a marking point at a position that can represent the linear change of the bridge to be measured, selecting a marking plate with a known calibration size, and pasting the marking plate at the marking point; Select a marker with known coordinates as the reference marker (x0, y0).

3. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The step of setting a drone shooting path and shooting images to obtain a first image set includes: The drone shooting path starts from the reference mark point, shoots all the mark points twice in the forward and return journeys, and finally returns to the reference mark point; Each photo must contain at least two marking points, and two adjacent photos must contain the same marking point. The photos are numbered in sequence according to the shooting path, and the shooting distance L and shooting angle θ of each photo are recorded.

4. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The correcting the first image to obtain a second image set includes: The photos are corrected according to the shooting distance L and the shooting angle θ, and each photo is restored to an image shot in an orthogonal state to obtain a second image set.

5. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The calculating and correcting the pixel size of the second image comprises: The pixel size is calculated according to the camera parameters and the shooting distance L, and the pixel size is corrected according to the marker of the known calibrated size.

6. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The identifying and calculating Δx and Δy between adjacent marking points includes: According to the number of the photos taken in the previous trip, starting from the reference mark point and ending at the last mark point, identify the distance between adjacent mark points in sequence. and According to the number of the photos taken on the return trip, starting from the last mark point and ending at the reference mark point, identify the distance between adjacent mark points in sequence. and Δx between adjacent marking points i and Δy i Calculated using the following formula:

7. The bridge linear image measurement method based on drone according to claim 1 is characterized in that: The step of calculating the measured coordinate values ​​of each marking point includes: The measured coordinates of each marker point are calculated using the following formula: x i =x0+Δx1+···+Δx i ,y i =y0+Δy1+···+Δy i 。 8. A terminal, characterized in that: The method comprises a processor, an input device, an output device and a memory, wherein the processor, the input device, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor is caused to perform the method according to any one of claims 1 to 7.

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