External parameter calibration method and device, electronic equipment and computer readable storage medium

Abstract

The application provides an external parameter calibration method and device, electronic equipment and computer readable storage medium, and relates to the technical field of visual measurement. The method comprises the following steps: acquiring first pose data of a shell structure in a calibration plate coordinate system; a target camera and an inertial unit are arranged in the shell structure, and the target camera and the inertial unit are rigidly connected; based on the first pose data, second pose data of the target camera in a shell coordinate system is determined; the angle of the inertial unit is calibrated, and third pose data of the inertial unit in the shell coordinate system is determined; and according to the second pose data and the third pose data, external parameter information between the target camera and the inertial unit is determined. The camera and the inertial unit are arranged in the same shell structure for unified processing, the pose of the shell structure can be determined first, and then the poses of the camera and the inertial unit in the shell structure are determined respectively, so that the external parameters of the camera and the inertial unit are calibrated, and the effect of external parameter calibration is optimized.

Description

Technical Field

[0001] This application relates to the field of visual measurement technology, and more specifically, to an external parameter calibration method, apparatus, electronic device, and computer-readable storage medium. Background Technology

[0002] In scenarios such as 3D reconstruction, visual odometry, and SLAM (Simultaneous Localization and Mapping), cameras and IMUs (Inertial Measurement Units) are usually combined into a whole through rigid bodies or rigid connections for measurement.

[0003] To determine the positional relationship between the camera and the IMU, extrinsic parameter calibration of the measurement system is required, typically using dynamic calibration. However, this method requires controlling the rigid body composed of the camera and IMU to perform specific movements, which places high demands on the trajectory, is difficult to control, complex to implement, and inefficient. Furthermore, the calibration process involves numerous calculations, is complex, and takes a long time, resulting in poor calibration results for the camera and IMU during extrinsic parameter calibration, thus adversely affecting the accuracy of visual measurements. Summary of the Invention

[0004] In view of this, the purpose of the embodiments of this application is to provide an external parameter calibration method, apparatus, electronic device and computer-readable storage medium to improve the problem of poor calibration effect when calibrating external parameters of cameras and IMUs in the prior art.

[0005] To address the aforementioned problems, in a first aspect, embodiments of this application provide an external parameter calibration method, the method comprising:

[0006] Obtain the first pose data of the shell structure in the calibration plate coordinate system; wherein, the shell structure is provided with a target camera and an inertial unit, and the target camera and the inertial unit are rigidly connected;

[0007] Based on the first pose data, the second pose data of the target camera in the shell coordinate system is determined;

[0008] The inertial unit is calibrated at an angle to determine the third pose data of the inertial unit in the shell coordinate system;

[0009] Based on the second pose data and the third pose data, the extrinsic parameter information between the target camera and the inertial unit is determined.

[0010] In the above implementation process, this application places the target camera and inertial unit in the same housing structure for unified processing. This allows for the initial determination of the housing structure's pose data in the calibration plate coordinate system, followed by the determination of the pose data of the target camera and inertial unit in the housing coordinate system. By transforming the two pose data from the same coordinate system, the extrinsic parameters of the external orientation elements between the target camera and the inertial unit are determined, enabling accurate and rapid extrinsic parameter calibration between them. Using a static measurement method for calibration is convenient to implement, has short operation time, low site requirements, high repeatability and consistency, and requires less data, resulting in lower computational costs. This effectively optimizes the extrinsic parameter calibration effect and enables automated mass production calibration.

[0011] Optionally, obtaining the first pose data of the shell structure in the calibration plate coordinate system includes:

[0012] The fourth pose data of the shell structure in the test coordinate system is obtained by visual measurement of the shell structure by the test camera.

[0013] The fifth pose data of the calibration board in the test coordinate system is obtained by visually measuring the calibration board with the test camera.

[0014] Based on the fourth pose data and the fifth pose data, the first pose data of the shell structure in the calibration plate coordinate system is determined.

[0015] In the above implementation process, visual measurements are performed on the shell structure and calibration plate using a test camera to determine the fourth and fifth pose data of the shell structure and calibration plate in the test camera coordinate system, respectively. Based on the fourth and fifth pose data, a corresponding transformation is performed to determine the first pose data of the shell structure in the calibration plate coordinate system. This allows for the accurate determination of the pose data of different objects in different coordinate systems through precise visual measurements and transformation calculations, effectively improving the efficiency and accuracy of acquiring the first pose data.

[0016] Optionally, determining the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the fifth pose data includes:

[0017] Based on the fifth pose data, the sixth pose data of the test camera in the calibration plate coordinate system is determined;

[0018] Based on the fourth pose data and the sixth pose data, the first pose data of the shell structure in the calibration plate coordinate system is determined.

[0019] In the above implementation process, during pose transformation, the sixth pose data of the test camera in the calibration plate coordinate system can be calculated first based on the fifth pose data. Then, coordinate system and pose transformation calculations are performed based on the fourth and sixth pose data to determine the first pose data of the shell structure in the calibration plate coordinate system. This allows for the determination of pose data of different objects in different coordinate systems based on pose transformations between different coordinate systems, effectively improving the efficiency and accuracy of acquiring the first pose data.

[0020] Optionally, the test camera is disposed outside the housing structure, and the test camera includes a binocular vision camera consisting of a first camera and a second camera.

[0021] In the above implementation process, in order to improve the accuracy of visual measurement of the shell structure and calibration plate, a binocular vision camera with a first camera and a second camera can be set on the outside of the shell structure to perform visual measurement through binocular vision, which effectively improves the accuracy of the fourth pose data and the fifth pose data, thereby further improving the accuracy of the first pose data obtained after conversion.

[0022] Optionally, determining the second pose data of the target camera in the housing coordinate system based on the first pose data includes:

[0023] The seventh pose data of the target camera in the coordinate system of the calibration board is obtained by visually measuring the calibration board with the target camera;

[0024] Based on the first pose data and the seventh pose data, the second pose data of the target camera in the housing coordinate system is obtained by conversion.

[0025] In the above implementation process, during calibration, since the structural dimensions or pattern dimensions of the calibration plate are standard, visual measurement of the calibration plate using a target camera within the shell structure allows for the acquisition of the target camera's seventh pose data in the calibration plate coordinate system. That is, both the first and seventh pose data are pose data in the calibration plate coordinate system. Therefore, based on the coordinate system to pose transformation calculation, the relative position of the target camera and the shell structure is determined, yielding the target camera's second pose data in the shell coordinate system. This ability to determine the pose data of different objects in different coordinate systems through pose transformation effectively improves the efficiency and accuracy of acquiring the second pose data.

[0026] Optionally, the step of calibrating the angle of the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system includes:

[0027] The installation angle of the inertial unit in the shell structure is determined based on the analysis of gravitational acceleration.

[0028] The third pose data of the inertial unit in the shell coordinate system is determined based on the installation angle.

[0029] In the above implementation, the installation angle of the inertial unit in the shell structure can be determined based on gravitational acceleration. Then, by considering factors such as structural design and mechanical constraints, the relative positional relationship between the inertial unit and the shell structure can be determined based on the installation angle, yielding the third pose data of the inertial unit in the shell coordinate system. Determining the third pose data is a static measurement method, eliminating the need for dynamic motion and measurement, effectively reducing the computational load and difficulty during measurement, and improving the accuracy and effectiveness of the third pose data.

[0030] Optionally, the step of determining the installation angle of the inertial unit in the shell structure based on gravitational acceleration analysis includes:

[0031] The shell structure was horizontally calibrated.

[0032] Acceleration data corresponding to multiple directional axes of the inertial unit are collected;

[0033] Calculations are performed based on multiple acceleration data to determine the component data of the gravitational acceleration on multiple direction axes;

[0034] The installation angle of the inertial unit in the housing structure is determined by calculation based on the component data.

[0035] In the above implementation process, to improve the accuracy of the mounting angle, the shell structure can be horizontally calibrated before testing. This allows for the acquisition of acceleration data corresponding to multiple directional axes of the inertial unit under static horizontal conditions, improving the accuracy and effectiveness of the acceleration data. Then, the distribution of neutral acceleration along multiple directional axes is calculated based on the acceleration data to obtain the corresponding component data. This component data is then used to determine the mounting angle of the inertial unit relative to the shell structure. The ability to determine the mounting angle in a static state reduces the difficulty of testing and the computational load, effectively improving the accuracy and effectiveness of the mounting angle.

[0036] Secondly, embodiments of this application also provide an external parameter calibration device, the device comprising: an acquisition module, a determination module, and a calibration module;

[0037] The acquisition module is used to acquire the first pose data of the shell structure in the calibration plate coordinate system; wherein, the shell structure is provided with a target camera and an inertial unit, and the target camera and the inertial unit are rigidly connected;

[0038] The determining module is used to determine the second pose data of the target camera in the shell coordinate system based on the first pose data; and to perform angle calibration on the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system.

[0039] The calibration module is used to determine the extrinsic parameter information between the target camera and the inertial unit based on the second pose data and the third pose data.

[0040] In the above implementation process, this application sets the target camera and the inertial unit in the same shell structure for unified processing. The acquisition module determines the pose data of the shell structure in the calibration plate coordinate system. The determination module determines the pose data of the target camera and the inertial unit in the shell coordinate system respectively. The calibration module converts the two pose data in the same coordinate system to determine the extrinsic parameter information of the external orientation elements between the target camera and the inertial unit, thereby realizing accurate and fast extrinsic parameter calibration between the target camera and the inertial unit.

[0041] Thirdly, embodiments of this application also provide an electronic device, which includes a memory and a processor. The memory stores program instructions, and when the processor reads and runs the program instructions, it executes the steps in any of the above-described implementations of the external parameter calibration method.

[0042] Fourthly, embodiments of this application also provide a computer-readable storage medium storing computer program instructions, which are read and executed by a processor to perform steps in any of the above-described external parameter calibration methods.

[0043] In summary, the embodiments of this application provide an extrinsic parameter calibration method, apparatus, electronic device, and computer-readable storage medium. By placing the camera and inertial unit in the same housing structure for unified processing, the pose of the housing structure can be determined first, and then the pose and coordinate system can be transformed to determine the pose of the camera and inertial unit in the housing structure respectively, so as to calibrate the extrinsic parameters of the camera and inertial unit, thereby optimizing the effect of extrinsic parameter calibration. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A block diagram illustrating an electronic device provided in an embodiment of this application;

[0046] Figure 2 A flowchart illustrating an external parameter calibration method provided in this application embodiment;

[0047] Figure 3 A detailed flowchart of step S200 provided for an embodiment of this application;

[0048] Figure 4 A detailed flowchart of step S230 provided for an embodiment of this application;

[0049] Figure 5 A detailed flowchart of step S300 provided for an embodiment of this application;

[0050] Figure 6 A detailed flowchart of step S400 provided for an embodiment of this application;

[0051] Figure 7 A detailed flowchart of step S410 provided for an embodiment of this application;

[0052] Figure 8 This is a schematic diagram of the structure of an external parameter calibration device provided in an embodiment of this application.

[0053] Icons: 100 - Electronic device; 111 - Memory; 112 - Memory controller; 113 - Processor; 114 - Peripheral interface; 115 - Input / output unit; 116 - Display unit; 600 - External parameter calibration device; 610 - Acquisition module; 620 - Determination module; 630 - Calibration module. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0055] The camera's external orientation elements, or external parameters, refer to the relative spatial position and attitude relationship between the camera and the IMU. They can include three translational relationships and three rotational relationships, which are the position and attitude transformation relationships between the IMU coordinate system and the camera coordinate system.

[0056] Current methods for extrinsic parameter calibration typically employ dynamic calibration. For example, in motion, the camera faces a calibration board with certain characteristic rules, and records the raw output data (acceleration, angular velocity) of the IMU for a period of time, while simultaneously recording the image data of the camera. The IMU trajectory is calculated separately, and the camera trajectory is calculated from the image. The relative spatial relationship between the IMU trajectory and the camera trajectory is calculated, thereby achieving the calibration of the extrinsic parameters of the camera in the IMU and camera combined system.

[0057] However, the applicant has found that this dynamic extrinsic parameter calibration method requires controlling a rigid body composed of a camera and an IMU to perform specific movements, such as rotating, translating, or performing figure-eight movements towards a specific calibration plate according to specific rules. During these movements, targeted adjustments are needed based on the characteristics of the camera and IMU within the rigid body. This requires precise control of the movement trajectory using robotic arms or similar methods, resulting in high trajectory requirements, significant control difficulties, and complex implementation. Furthermore, due to limitations imposed by factors such as camera exposure time and IMU range, the speed of the movement trajectory is limited to a certain maximum speed, leading to low calibration efficiency. Additionally, it typically requires recording at least one minute of motion data, resulting in lengthy computation time. The calibration process involves numerous calculations, is complex and challenging, requiring high-performance computers and incurring high computational costs. The entire calibration process is also affected by factors such as motion and fiber optics, leading to poor consistency and accuracy during calibration. This makes automated and mass-producible extrinsic parameter calibration difficult, resulting in poor calibration performance for cameras and IMUs, thus negatively impacting the accuracy of visual measurements.

[0058] To address the aforementioned issues, this application provides an extrinsic parameter calibration method applicable to electronic devices. These devices can be servers, personal computers (PCs), tablets, smartphones, personal digital assistants (PDAs), or other electronic devices with logical computing capabilities. The method can communicate with the target camera, inertial unit, and test camera outside the housing structure in a vision measurement system to acquire the transmitted pose data and perform corresponding pose and coordinate system transformations, thereby achieving efficient and high-precision extrinsic parameter calibration.

[0059] Optionally, please refer to Figure 1 , Figure 1 This is a block diagram illustrating an electronic device according to an embodiment of this application. The electronic device 100 may include a memory 111, a memory controller 112, a processor 113, a peripheral interface 114, an input / output unit 115, and a display unit 116. Those skilled in the art will understand that... Figure 1The structure shown is for illustrative purposes only and does not limit the structure of the electronic device 100. For example, the electronic device 100 may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0060] The aforementioned memory 111, memory controller 112, processor 113, peripheral interface 114, input / output unit 115, and display unit 116 are electrically connected directly or indirectly to each other to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The aforementioned processor 113 is used to execute executable modules stored in the memory.

[0061] The memory 111 can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The memory 111 stores programs. After receiving execution instructions, the processor 113 executes the programs. The methods executed by the electronic device 100 as defined in any embodiment of this application can be applied to the processor 113, or implemented by the processor 113.

[0062] The aforementioned processor 113 may be an integrated circuit chip with signal processing capabilities. The processor 113 may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a digital signal processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor.

[0063] The peripheral interface 114 described above couples various input / output devices to the processor 113 and the memory 111. In some embodiments, the peripheral interface 114, the processor 113, and the memory controller 112 can be implemented on a single chip. In other instances, they can be implemented on separate chips.

[0064] The input / output unit 115 described above is used to provide user input data. The input / output unit 115 can be, but is not limited to, a mouse and a keyboard.

[0065] The aforementioned display unit 116 provides an interactive interface (e.g., a user interface) between the electronic device 100 and the user, or displays image data for the user's reference. In this embodiment, the display unit can be a liquid crystal display (LCD) or a touch display. If it is a touch display, it can be a capacitive touchscreen or a resistive touchscreen that supports single-point and multi-point touch operations. Supporting single-point and multi-point touch operations means that the touch display can sense touch operations generated simultaneously from one or more locations on the touch display and pass the sensed touch operations to the processor for calculation and processing. In this embodiment, the display unit 116 can display various data such as acquired pose data and finally determined extrinsic parameter information.

[0066] The electronic device in this embodiment can be used to execute the various steps in the extrinsic parameter calibration methods provided in the embodiments of this application. The implementation process of the extrinsic parameter calibration methods is described in detail below through several embodiments.

[0067] Please see Figure 2 , Figure 2 This is a flowchart illustrating an external parameter calibration method provided in an embodiment of this application. The method may include steps S200-S500.

[0068] Step S200: Obtain the first pose data of the shell structure in the calibration plate coordinate system.

[0069] The shell structure houses the target camera and inertial unit, which are rigidly connected. For example, the target camera and inertial unit can be rigidly connected via welded steel pipes, and then fixed within the rigid shell structure. The shell structure can be a cube, cuboid, sphere, or other shape selected according to actual conditions and requirements to form a complete measurement system. The calibration plate can be a standard checkerboard calibration plate or other types of calibration plates, which can be fixed at the appropriate position during measurement for measurement and conversion calculations. Based on multiple visual measurements and coordinate system / pose transformations, the first pose data of the shell structure in the calibration plate coordinate system can be determined.

[0070] Step S300: Based on the first pose data, determine the second pose data of the target camera in the shell coordinate system.

[0071] Specifically, coordinate system and pose transformation processing can be performed based on the first pose data to determine the relative positional relationship between the target camera and the shell structure, thereby obtaining the second pose data of the target camera in the shell coordinate system.

[0072] Step S400: Perform angle calibration on the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system.

[0073] Since the inertial element can calculate velocity data at various angles, the angle of the inertial element can be calibrated when the shell structure is stationary to determine the relative positional relationship between the inertial element and the shell structure, so as to obtain the second pose data of the inertial element in the shell coordinate system.

[0074] Step S500: Determine the extrinsic parameter information between the target camera and the inertial unit based on the second pose data and the third pose data.

[0075] Since both the second and third pose data are pose data in the shell coordinate system, calculations can be performed directly based on the second and third pose data to determine the relative positional relationship between the target camera and the inertial unit, and to obtain the extrinsic parameter information between them.

[0076] For example, the extrinsic parameter information may include the pose data of the inertial unit in the coordinate system of the target camera, and the pose data of the target camera in the coordinate system of the inertial unit.

[0077] Optionally, the first pose data, the second pose data, the third pose data, and other pose data all include the spatial position information and attitude information of the corresponding object in the corresponding coordinate system, such as specific three-dimensional coordinate information and pose angle information.

[0078] exist Figure 2 In the illustrated embodiment, a static measurement method is used for calibration. Calibration is easy to implement, has a short operation time, low site requirements, high repeatability and consistency, and requires less data and has a lower computational cost. This effectively optimizes the calibration of external parameters and enables automated mass production calibration.

[0079] Optionally, please refer to Figure 3 , Figure 3 This is a detailed flowchart of step S200 provided in an embodiment of the present application. Step S200 may also include steps S210-S230.

[0080] Step S210: Obtain the fourth pose data of the shell structure in the test coordinate system obtained by the test camera through visual measurement of the shell structure.

[0081] In order to measure the pose of the shell structure, a corresponding test camera can be set on the outside of the shell structure for visual measurement. The electronic device can obtain the fourth pose data of the shell structure in the test coordinate system measured by the test camera through communication connection.

[0082] Step S220: Obtain the fifth pose data of the calibration board in the test coordinate system obtained by the test camera performing visual measurement on the calibration board.

[0083] The test camera can also measure the calibration board, and the electronic device can obtain the fifth pose data of the calibration board in the test coordinate system measured by the test camera through a communication connection.

[0084] It should be noted that the calibration plate coordinate system is a three-dimensional coordinate system established with the midpoint of the calibration plate as the center, the shell coordinate system is a three-dimensional coordinate system established with the midpoint of the shell structure as the center, and the test coordinate system is a three-dimensional coordinate system established with the midpoint of the test camera as the center.

[0085] Step S230: Based on the fourth pose data and the fifth pose data, determine the first pose data of the shell structure in the calibration plate coordinate system.

[0086] Specifically, coordinate system and pose transformation calculations can be performed based on the fourth and fifth pose data to determine the first pose data of the shell structure in the calibration plate coordinate system.

[0087] It should be noted that the execution order of steps S210 and S220 can be selected and adjusted according to the actual situation, and there is no restriction on their order. Furthermore, the test camera is located outside the housing structure. The test camera may include a binocular vision camera composed of a first camera and a second camera, to perform visual measurements through binocular vision, effectively improving the accuracy of the fourth and fifth pose data, thereby further improving the accuracy of the first pose data obtained after conversion.

[0088] exist Figure 3 In the illustrated embodiment, the pose data of different objects in different coordinate systems can be determined based on accurate visual measurements and transformation calculations, effectively improving the efficiency and accuracy of acquiring the first pose data.

[0089] Optionally, please refer to Figure 4 , Figure 4 This is a detailed flowchart of step S230 provided in an embodiment of the present application. Step S230 may also include steps S231-S232.

[0090] Step S231: Based on the fifth pose data, determine the sixth pose data of the test camera in the calibration plate coordinate system.

[0091] During pose transformation, the fifth pose data is the pose data of the calibration plate in the test coordinate system. Since the relative position between the calibration plate and the test camera is fixed during measurement, and the structural dimensions or pattern dimensions of the calibration plate are standard, the sixth pose data of the test camera in the calibration plate coordinate system can be calculated from the fifth pose data.

[0092] Step S232: Based on the fourth pose data and the sixth pose data, determine the first pose data of the shell structure in the calibration plate coordinate system.

[0093] By combining the sixth pose data of the test camera in the calibration plate coordinate system and the fourth pose data of the shell structure in the test coordinate system, the coordinate system and pose transformation calculation can be performed to determine the first pose data of the shell structure in the calibration plate coordinate system.

[0094] exist Figure 4 In the illustrated embodiment, the pose data of different objects in different coordinate systems can be determined based on the pose transformation between different coordinate systems, effectively improving the efficiency and accuracy of acquiring the first pose data.

[0095] Optionally, please refer to Figure 5 , Figure 5 This is a detailed flowchart of step S300 provided in an embodiment of the present application. Step S300 may also include steps S310-S320.

[0096] Step S310: Obtain the seventh pose data of the target camera in the calibration plate coordinate system obtained by visual measurement of the calibration plate by the target camera.

[0097] During calibration, since the structural or pattern dimensions of the calibration plate are standard, the relative position between the target camera and the calibration plate can be measured first by visually measuring the calibration plate through the target camera in the shell structure, so as to obtain the seventh pose data of the target camera in the calibration plate coordinate system.

[0098] Step S320: Based on the first pose data and the seventh pose data, a transformation is performed to obtain the second pose data of the target camera in the shell coordinate system.

[0099] Since both the first pose data and the seventh pose data are pose data in the calibration plate coordinate system, the relative position of the target camera and the shell structure can be determined in the calibration plate coordinate system, and the coordinate system and pose transformation calculation can be performed to obtain the second pose data of the target camera in the shell coordinate system.

[0100] exist Figure 5 In the illustrated embodiment, the pose data of different objects in different coordinate systems can be determined based on the pose transformation between different coordinate systems, which effectively improves the efficiency and accuracy of acquiring the second pose data.

[0101] Optionally, please refer to Figure 6 , Figure 6 This is a detailed flowchart of step S400 provided in an embodiment of the present application. Step S400 may also include steps S410-S420.

[0102] Step S410: Based on the analysis of gravitational acceleration, determine the installation angle of the inertial unit in the shell structure.

[0103] Among these methods, the inertial element's directional components can be analyzed based on gravitational acceleration to determine the inertial element's installation angle within the shell structure.

[0104] Step S420: Determine the third pose data of the inertial unit in the shell coordinate system based on the installation angle.

[0105] Among them, the relative positional relationship between the inertial unit and the shell structure can be determined based on the installation angle by factors such as structural design and mechanical limit, so as to obtain the third pose data of the inertial unit in the shell coordinate system.

[0106] exist Figure 6 In the embodiment shown, the measurement method for determining the third pose data is a static state, which does not require dynamic movement and measurement, effectively reducing the amount of calculation and difficulty during measurement, and improving the accuracy and effectiveness of the third pose data.

[0107] Optionally, please refer to Figure 7 , Figure 7 This is a detailed flowchart of step S410 provided in an embodiment of the present application. Step S410 may also include steps S411-S414.

[0108] Step S411: Perform horizontal calibration on the shell structure.

[0109] To improve the accuracy of the installation angle, the housing structure can be horizontally calibrated before testing. For example, during horizontal calibration, the housing structure can be placed on a standard horizontal surface calibrated by instruments such as a level, and electronic equipment can be used to check the placement plane of the housing structure to determine if the horizontality meets the testing requirements.

[0110] Step S412: Collect acceleration data corresponding to multiple directional axes of the inertial unit.

[0111] Among them, the acceleration data of the inertial unit in multiple directions under horizontal static conditions can be collected separately. The multiple directions can be three-dimensional x, y, and z axes.

[0112] Step S413: Calculate based on multiple acceleration data to determine the component data of gravitational acceleration on multiple directional axes.

[0113] Among them, the distribution relationship of neutral acceleration on multiple directional axes can be calculated based on acceleration data to obtain the corresponding component data.

[0114] Step S414: Calculate based on component data to determine the installation angle of the inertial unit in the shell structure.

[0115] The component data allows for the calculation of the actual angles of the inertial element on each directional axis, thereby determining the installation angle of the inertial element relative to the shell structure.

[0116] exist Figure 7 In the illustrated embodiment, the installation angle can be determined in a static state, reducing the difficulty and computational load of testing, and effectively improving the accuracy and effectiveness of the installation angle.

[0117] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of an external parameter calibration device provided in an embodiment of the present application. The external parameter calibration device 600 may include: an acquisition module 610, a determination module 620 and a calibration module 630.

[0118] The acquisition module 610 is used to acquire the first pose data of the shell structure in the calibration plate coordinate system; wherein, the shell structure is provided with a target camera and an inertial unit, and the target camera and the inertial unit are rigidly connected;

[0119] The determination module 620 is used to determine the second pose data of the target camera in the shell coordinate system based on the first pose data; and to perform angle calibration on the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system.

[0120] The calibration module 630 is used to determine the extrinsic parameter information between the target camera and the inertial unit based on the second pose data and the third pose data.

[0121] In an optional implementation, the acquisition module 610 is specifically used to: acquire the fourth pose data of the shell structure in the test coordinate system obtained by the test camera visually measuring the shell structure; acquire the fifth pose data of the calibration plate in the test coordinate system obtained by the test camera visually measuring the calibration plate; and determine the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the fifth pose data.

[0122] In an optional implementation, the acquisition module 610 is specifically used to: determine the sixth pose data of the test camera in the calibration plate coordinate system based on the fifth pose data; and determine the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the sixth pose data.

[0123] In an optional embodiment, the test camera is disposed outside the housing structure, and the test camera includes a binocular vision camera consisting of a first camera and a second camera.

[0124] In an optional implementation, the determining module 620 may include a first determining submodule, used to acquire the seventh pose data of the target camera in the calibration plate coordinate system obtained by the target camera performing visual measurements on the calibration plate; and to convert the first pose data and the seventh pose data to obtain the second pose data of the target camera in the shell coordinate system.

[0125] In an optional implementation, the determination module 620 may include a second determination submodule for performing analysis based on gravitational acceleration to determine the installation angle of the inertial unit in the shell structure; and determining the third pose data of the inertial unit in the shell coordinate system based on the installation angle.

[0126] In an optional implementation, the second determining submodule is specifically used for: performing horizontal calibration on the shell structure; acquiring acceleration data corresponding to multiple directional axes of the inertial unit; calculating based on the multiple acceleration data to determine the component data of gravitational acceleration on multiple directional axes; and calculating based on the component data to determine the installation angle of the inertial unit in the shell structure.

[0127] Since the principle of the external parameter calibration device 600 in this embodiment is similar to that of the aforementioned external parameter calibration method, the implementation of the external parameter calibration device 600 in this embodiment can refer to the description in the aforementioned external parameter calibration method, and the repeated parts will not be described again.

[0128] This application also provides a computer-readable storage medium storing computer program instructions. When the computer program instructions are read and executed by a processor, they perform the steps of any of the external parameter calibration methods provided in this embodiment.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely illustrative; for example, the block diagrams in the accompanying drawings illustrate the possible architecture, functions, and operations of the device according to various embodiments of this application. In this regard, each block in the block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram, and combinations of block diagrams, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0130] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0131] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0132] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0133] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0134] It should be noted that, in this document, relational terms such as "first" and "second" are used merely 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..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for calibrating external parameters, characterized in that, The method includes: Obtain the first pose data of the shell structure in the calibration plate coordinate system; wherein, the shell structure is provided with a target camera and an inertial unit, and the target camera and the inertial unit are rigidly connected; Based on the first pose data, the second pose data of the target camera in the shell coordinate system is determined; The inertial unit is calibrated at an angle to determine the third pose data of the inertial unit in the shell coordinate system; Based on the second pose data and the third pose data, the extrinsic parameter information between the target camera and the inertial unit is determined; The step of obtaining the first pose data of the shell structure in the calibration plate coordinate system includes: obtaining the fourth pose data of the shell structure in the test coordinate system obtained by the test camera performing visual measurements on the shell structure; obtaining the fifth pose data of the calibration plate in the test coordinate system obtained by the test camera performing visual measurements on the calibration plate; and determining the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the fifth pose data.

2. The method according to claim 1, characterized in that, The step of determining the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the fifth pose data includes: Based on the fifth pose data, the sixth pose data of the test camera in the calibration plate coordinate system is determined; Based on the fourth pose data and the sixth pose data, the first pose data of the shell structure in the calibration plate coordinate system is determined.

3. The method according to claim 1, characterized in that, in, The test camera is disposed outside the housing structure, and the test camera includes a binocular vision camera consisting of a first camera and a second camera.

4. The method according to any one of claims 1-3, characterized in that, The step of determining the second pose data of the target camera in the shell coordinate system based on the first pose data includes: The seventh pose data of the target camera in the coordinate system of the calibration board is obtained by visually measuring the calibration board with the target camera; Based on the first pose data and the seventh pose data, the second pose data of the target camera in the housing coordinate system is obtained by conversion.

5. The method according to any one of claims 1-3, characterized in that, The step of calibrating the angle of the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system includes: The installation angle of the inertial unit in the shell structure is determined based on the analysis of gravitational acceleration. The third pose data of the inertial unit in the shell coordinate system is determined based on the installation angle.

6. The method according to claim 5, characterized in that, The analysis based on gravitational acceleration to determine the installation angle of the inertial unit in the shell structure includes: The shell structure was horizontally calibrated. Acceleration data corresponding to multiple directional axes of the inertial unit are collected; Calculations are performed based on multiple acceleration data to determine the component data of the gravitational acceleration on multiple direction axes; The installation angle of the inertial unit in the housing structure is determined by calculation based on the component data.

7. An external parameter calibration device, characterized in that, The device includes: an acquisition module, a determination module, and a calibration module; The acquisition module is used to acquire the first pose data of the shell structure in the calibration plate coordinate system; wherein, the shell structure is provided with a target camera and an inertial unit, and the target camera and the inertial unit are rigidly connected; The determining module is used to determine the second pose data of the target camera in the shell coordinate system based on the first pose data; and to perform angle calibration on the inertial unit to determine the third pose data of the inertial unit in the shell coordinate system. The calibration module is used to determine the extrinsic parameter information between the target camera and the inertial unit based on the second pose data and the third pose data; The acquisition module is specifically used for: acquiring the fourth pose data of the shell structure in the test coordinate system obtained by the test camera performing visual measurements on the shell structure; acquiring the fifth pose data of the calibration plate in the test coordinate system obtained by the test camera performing visual measurements on the calibration plate; and determining the first pose data of the shell structure in the calibration plate coordinate system based on the fourth pose data and the fifth pose data.

8. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores program instructions, and when the processor executes the program instructions, it performs the steps of the method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The readable storage medium stores computer program instructions, which, when executed by a processor, perform the steps of the method according to any one of claims 1-6.

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