Calibration device and method for external parameters of camera

Abstract

The embodiment of the invention provides an external parameter calibration device of a camera. The external parameter calibration device comprises a rotating module, a guide moving module, a control module, a calibration plate and an external parameter calibration module, the rotating module is connected with the to-be-calibrated equipment and is used for rotating in response to the rotating control signal so as to drive the to-be-calibrated equipment to rotate; the guiding and moving module is connected with the calibration plate and used for responding to the displacement control signal and moving the calibration plate; and the external parameter calibration module is used for responding to the calibration control signal, acquiring the positioning data of the calibration plate relative to the to-be-calibrated equipment under the condition that the current to-be-calibrated camera of the to-be-calibrated equipment rotates to be aligned with the calibration plate and the imaging picture of the camera comprises the calibration plate, and calibrating the external parameter of the camera based on the positioning data. According to the external parameter calibration device of the camera provided by the embodiment of the invention, the position distance between the to-be-calibrated equipment and the calibration plate can be automatically adjusted, and the external parameter calibration of the camera can be quickly realized under the condition that there is no need to have an overlapped view field between the cameras.

Description

Technical Field

[0001] The present application relates to the technical field of machine vision, and particularly to an external parameter calibration device and method for a camera. Background Art

[0002] Generally speaking, devices equipped with multiple cameras often require cooperation among the multiple cameras to accurately and comprehensively identify external scenes. For example, stack cameras, multi-camera stereo cameras, intelligent vehicles, etc. Taking an intelligent vehicle that needs to achieve autonomous driving as an example, a single on-vehicle camera is difficult to meet the vehicle's perception requirements for the surrounding 360° environment. Therefore, multiple cameras are often arranged around the vehicle to achieve accurate and comprehensive environmental perception. Environmental perception is also one of the core technologies in the field of autonomous driving and is the only way for a vehicle to achieve autonomous driving.

[0003] In the same device, each camera needs to determine its position and orientation in the same three-dimensional space to cooperate with each other to achieve the mapping from world coordinates to pixel coordinates. Therefore, to enable the cameras to cooperate with each other, it is necessary to calibrate the external parameters of the camera, that is, the external parameters (Camera Extrinsics) of the camera.

[0004] In related technologies, considering various factors such as cost and perception ability, it is necessary to perform manual calibration based on the camera layout, the number of cameras, and the camera viewing angle of an intelligent vehicle, which not only consumes a large amount of manpower and material resources, but also cannot guarantee the accuracy of camera calibration. Summary of the Invention

[0005] To solve the above problems, the embodiments of the present application propose an external parameter calibration device for a camera and an external parameter calibration method for a camera, aiming to solve or partially solve the problem that it is impossible to quickly and efficiently calibrate the external parameters of a camera when there is no overlapping field of view between cameras.

[0006] The embodiments of the present application provide an external parameter calibration device for a camera, including: a rotation module, a translation module, a control module, a calibration board, and an external parameter calibration module; wherein, a signal connection is established between the control module and the rotation module, the translation module, and the external parameter calibration module respectively;

[0007] The control module is configured to transmit a rotation control signal to the rotation module, and is configured to transmit a displacement control signal to the translation module, and is further configured to transmit a calibration control signal to the external parameter calibration module;

[0008] The rotation module is connected to the device to be calibrated and is configured to rotate in response to the rotation control signal to drive the device to be calibrated to rotate;

[0009] The guide module is connected to the calibration plate and is used to move the calibration plate in response to the displacement control signal;

[0010] The external parameter calibration module is used to respond to the calibration control signal, and when the current camera to be calibrated of the device to be calibrated is rotated to be aligned with the calibration plate and the imaging picture of the camera includes the calibration plate, obtain the positioning data of the calibration plate relative to the device to be calibrated, and calibrate the external parameters of the camera based on the positioning data.

[0011] Optionally, the rotation module comprises: a first feedback unit, configured to transmit a first feedback signal to the control module after rotating the device to be calibrated to a target angle;

[0012] The guide module includes: a second feedback unit, which is used to transmit a second feedback signal to the control module after moving the calibration plate to the target position;

[0013] The control module includes: a signal acquisition unit, configured to receive the first feedback signal and the second feedback signal;

[0014] The control module is further configured to transmit the control signal to the external parameter calibration module after receiving the first feedback signal and the second feedback signal.

[0015] Optionally, the external parameter calibration module includes: a relay radar;

[0016] The relay radar is arranged on a side of the device to be calibrated away from the rotating module, and is used to respond to the calibration control signal, start and send out radar signals, and receive and collect the positioning data fed back from the calibration board to the location of the device to be calibrated.

[0017] Optionally, the control module includes: a clock synchronization unit; the clock synchronization unit establishes a signal connection with the camera of the device to be calibrated and the external parameter calibration module;

[0018] The clock synchronization unit is used to synchronize the start or shut down time of the external parameter calibration module with the current camera to be calibrated of the device to be calibrated by transmitting a synchronization clock signal to the current camera to be calibrated and the external parameter calibration module.

[0019] Optionally, the control module includes: a device control unit; the device control unit establishes a signal connection with a camera of the device to be calibrated;

[0020] The device control unit is configured to transmit the control signal to the currently calibrated camera of the device to be calibrated after the control module receives the first feedback signal and the second feedback signal, so as to control the currently calibrated camera of the device to be calibrated to turn on.

[0021] Optionally, the external parameter calibration module further includes:

[0022] A first external parameter calculation unit, configured to obtain the external parameter between the relay radar and any one camera in the device to be calibrated according to the positioning data;

[0023] A second external parameter calculation unit, configured to obtain the external parameter between any two cameras in the device to be calibrated according to the external parameters between the relay radar and any two cameras in the device to be calibrated.

[0024] Optionally, the rotation module includes: a rotating table, configured to fix and drive the device to be calibrated to rotate;

[0025] A guiding and moving module, including: a calibration bracket and a guide rail, where the calibration bracket is configured to fix and drive the calibration plate to move along the track direction of the guide rail;

[0026] Wherein, the straight line along the track direction of the guide rail passes through the rotating table.

[0027] Optionally, the rotating table further includes:

[0028] A first device rotation unit, configured to drive the device to be calibrated to rotate along a first rotation axis;

[0029] A second device rotation unit, configured to drive the device to be calibrated to rotate along a second rotation axis;

[0030] A positioning mark, facing the intersection of the first rotation axis and the second rotation axis, configured to position the device to be calibrated;

[0031] Wherein, the first rotation axis and the second rotation axis intersect and are perpendicular to each other.

[0032] Optionally, the calibration bracket further includes:

[0033] A first calibration rotation unit, configured to drive the calibration plate to rotate along a third rotation axis;

[0034] A second calibration rotation unit, configured to drive the calibration plate to rotate along a fourth rotation axis;

[0035] Wherein, the third rotation axis and the fourth rotation axis intersect and are perpendicular to each other.

[0036] Compared with the prior art, the device described in the embodiments of the present application has the following advantages:

[0037] (1) In the prior art, the external parameters of a camera can be automatically calibrated only when there is an overlapping field of view between cameras. However, the external parameter calibration device for a camera provided in the embodiments of the present application calibrates the external parameters of the cameras of the device to be calibrated by using a calibration board. Even if there is no overlapping field of view among the cameras, as long as there is a calibration board in the captured image and the position of the calibration board can be determined, then each camera can use the calibration board as a reference object for calibration in a unified field of view, so that the calibration of the external parameters of multiple cameras can be completed without relying on the participation of an overlapping field of view. Therefore, the embodiments of the present application use the calibration board as a medium for camera calibration, and can realize the automatic calibration of the external parameters of the camera without considering whether there is an overlapping field of view between cameras, regardless of whether there is an overlapping field of view between cameras.

[0038] (2) The external parameter calibration device for a camera provided in the embodiments of the present application, on the basis of using a calibration board to calibrate the external parameters of the camera, provides a rotation module to rotate the device to be calibrated, and also provides a guiding and moving module to control the movement of the calibration board, so as to obtain a calibration board facing the front in the field of view of each camera of the device to be calibrated, and then the external parameter calibration module can calibrate each camera of the device to be calibrated with the calibration board as a reference. Thus, the embodiments of the present application have no special requirements for the calibration environment such as the placement position of the calibration board and the angular position of the device to be calibrated, and the calibration result does not depend on a high-precision calibration environment, effectively reducing the calibration cost.

[0039] (3) In the prior art, for the situation where there is no overlapping field of view between cameras, manual intervention is time-consuming, laborious and has a large error. The external parameter calibration device for a camera provided in the embodiments of the present application uses a rotation module and a guiding and moving module to adjust and change the relative angle and relative position between the device to be calibrated and the calibration board, and can automatically obtain a calibration board facing the front in the field of view of each camera of the device to be calibrated, that is, automatically realize the conditions for calibrating the external parameters of the camera, saving a large number of links involving manual participation, thereby greatly improving the calibration efficiency and accuracy of the external parameters of the camera.

[0040] The embodiments of the present application also provide a method for calibrating the external parameters of a camera, including:

[0041] The control module transmits a rotation control signal to the rotation module and a displacement control signal to the guiding and moving module;

[0042] The rotation module rotates in response to the rotation control signal to drive the device to be calibrated to rotate;

[0043] The guiding and moving module moves the calibration board in response to the displacement control signal;

[0044] Determine whether the current camera to be calibrated of the device to be calibrated is aligned with the calibration board, and determine whether the imaging screen of this camera includes the calibration board;

[0045] When the current camera to be calibrated of the device to be calibrated rotates to be aligned with the calibration board and the imaging screen of this camera includes the calibration board, the control module transmits a calibration control signal to the external parameter calibration module;

[0046] The external parameter calibration module, in response to the calibration control signal, acquires the positioning data of the calibration board relative to the device to be calibrated, and calibrates the external parameters of this camera based on the positioning data.

[0047] Optionally, the step of determining whether the current camera to be calibrated of the device to be calibrated is aligned with the calibration board and determining whether the imaging screen of this camera includes the calibration board includes:

[0048] Start the current camera to be calibrated and acquire the imaging screen;

[0049] Grab the image of the calibration board in the imaging screen of the current camera to be calibrated through a preset image detection algorithm;

[0050] Determine whether the imaging screen of this camera includes the calibration board;

[0051] When the imaging screen of this camera includes the calibration board, detect the shooting angle of the calibration board through the preset image detection algorithm to determine whether the current camera to be calibrated of the device to be calibrated is aligned with the calibration board.

[0052] Optionally, the step of determining whether the imaging screen of this camera includes the calibration board includes:

[0053] Judge whether the image of the calibration board meets the preset conditions through the preset image detection algorithm; the preset conditions include that the image of the calibration board is complete and the proportion of the area occupied by the image of the calibration board in the imaging screen is within a preset proportion range;

[0054] If so, determine that the imaging screen of this camera includes the calibration board;

[0055] If so, judge that the imaging screen of this camera includes the calibration board.

[0056] Compared with the prior art, the method provided by the embodiments of the present application has the same or similar inventive concept as the device provided by the embodiments of the present application. Therefore, the method provided by the embodiments of the present application also has the advantages of the device provided by the embodiments of the present application. Description of the Drawings

[0057] Figure 1 It is a structural block diagram of an external parameter calibration device for a camera provided by an embodiment of the present application;

[0058] Figure 2 It is a working schematic diagram of an external parameter calibration device for a camera provided by an embodiment of the present application;

[0059] Figure 3 It is a working schematic diagram of an external parameter calibration module provided by an embodiment of the present application;

[0060] Figure 4 It is a structural schematic diagram of a guiding and moving module provided by an embodiment of the present application;

[0061] Figure 5 It is a structural schematic diagram of a positioning mark provided by an embodiment of the present application;

[0062] Figure 6 It is a step flowchart of an external parameter calibration method for a camera provided by an embodiment of the present application;

[0063] Figure 7 It is a step flowchart of a method for determining an image of a calibration board in an imaging screen provided by an embodiment of the present application.

[0064] Reference numerals:

[0065] 10. Rotation module; 11. Rotation table; 12. Positioning mark; 20. Guiding and moving module; 21. Calibration bracket; 22. Guide rail; 30. Control module; 40. Calibration board; 50. External parameter calibration module; 51. Relay radar; 52. Radar base; 90. Device to be calibrated; 9-1. First camera; 9-2. Second camera; 9-3. Third camera; 9-4. Fourth camera; 9-5. Fifth camera; 9-6. Sixth camera. Detailed implementation manners

[0066] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0067] The inventors found that in the prior art, for a device equipped with multiple cameras, such as an intelligent vehicle, it is often necessary to have a field of view overlap between the in-vehicle cameras in order to automatically calibrate the external parameters of the cameras. In order to achieve a 360° field of view coverage without dead angles, a relatively large number of cameras need to be arranged around the same device to ensure that there is a field of view coverage between each camera. However, this will lead to an increase in the manufacturing cost of the vehicle and the occupation of the vehicle space. If there is no common viewing area between the cameras, the process of calibrating the external parameters is much more complicated, requiring manual intervention and the use of external devices to measure multiple sets of data. Moreover, the calibration of such external parameters has extremely high precision requirements for the placement position of the external device, the angle and position of the device to be calibrated, etc., and the calibration result completely depends on the precision error of the calibration environment. Obviously, the current calibration of the external parameters of the cameras not only requires an overlapping field of view between the cameras, has high requirements for environmental equipment, but also requires a large amount of manual participation, resulting in low efficiency and accuracy of the calibration of the external parameters of multi-camera devices. Therefore, in the case where there is no overlapping field of view between the cameras, how to quickly and efficiently calibrate the external parameters of the cameras is an urgent problem to be solved by those skilled in the art.

[0068] To solve the above problems, an embodiment of the present application provides an external parameter calibration device for a camera and an external parameter calibration method for a camera, so as to solve the problem that the external parameters of the camera can be quickly and efficiently calibrated even when there is no overlapping field of view between the cameras.

[0069] The following will describe the present application in detail with reference to the accompanying drawings.

[0070] Referring to Figure 1 , Figure 1 is a structural block diagram of an external parameter calibration device for a camera provided by an embodiment of the present application. As Figure 1 shown, an embodiment of the present application provides an external parameter calibration device for a camera, which can be applied to the calibration of the external parameters of the cameras of the device 90 to be calibrated, and the device 90 to be calibrated may include a multi-camera device. Among them, the multi-camera device includes but is not limited to one of the following: a stack camera, a multi-camera stereo camera, and a vehicle with multiple cameras.

[0071] Among them, for the external parameter calibration device of the camera, the module size and position therein can be set according to the shape of the multi-camera device to which it is applied. Exemplarily, if the device 90 to be calibrated is a vehicle with multiple cameras, the rotation module that is connected to the device 90 to be calibrated and needs to drive the device 90 to be calibrated to rotate can be set to a size similar to that of the vehicle. For example, the rotation module may include: a rotatable turntable that can carry and drive the vehicle.

[0072] Specifically, the device 90 to be calibrated may include at least two cameras. Taking a vehicle as an example, for autonomous driving, environmental perception is required. Six cameras may be distributed around the vehicle to achieve all-round environmental perception. In order to further unify the fields of view of the cameras, external parameter calibration of the cameras in the intelligent vehicle is required. Therefore, the device 90 to be calibrated may include the vehicle to be calibrated.

[0073] The external parameter calibration device for a camera provided in an embodiment of the present application includes: a rotation module 10, a guiding and moving module 20, a control module 30, a calibration board 40, and an external parameter calibration module 50. Among them, signal connections are established between the control module 30 and the rotation module 10, the guiding and moving module 20, and the external parameter calibration module 50 respectively.

[0074] In an alternative embodiment, the external parameter calibration module 50 includes at least a radar.

[0075] Among them, the control module 30 may include a console frame. In the console frame, there may also be a programmable device, and the programmable device includes at least one of a microcontroller unit (MCU), a central processing unit (CPU), and a field programmable gate array (FPGA). The logical functions of the programmable device can be realized by pre-writing a programming language to perform actions such as transmitting signals, receiving signals, and data calculation in the following embodiments.

[0076] Specifically, the signal connection may be established in the form of a controller area network (CAN).

[0077] In another alternative embodiment, the signal connection may also be established in the form of a wireless network. The wireless network may include a fifth generation mobile communication technology (5G) network.

[0078] The control module 30 is configured to transmit a rotation control signal to the rotation module 10, and is further configured to transmit a displacement control signal to the guiding and moving module 20, and is further configured to transmit a calibration control signal to the external parameter calibration module 50.

[0079] Among them, during the calibration process of multiple cameras, if after the calibration of camera A is completed, the guiding module 20 drives the calibration board to move to a position where the calibration of camera B can be carried out, for the calibration of the current camera B, it only needs the rotation module 10 to drive the device 90 to be calibrated to rotate, without the displacement of the calibration board 40. Then, during the calibration process of this camera B, the control module 30 can also only transmit control signals to the rotation module 10 and the external parameter calibration module 50.

[0080] Among them, the control signals transmitted by the control module 30 include: digital quantity signals.

[0081] The rotation module 10 is connected to the device 90 to be calibrated and is used to rotate in response to the rotation control signal to drive the device 90 to be calibrated to rotate.

[0082] In the embodiment of the present application, the rotation module 10 drives the device 90 to be calibrated to rotate, that is, drives the camera on the device 90 to be calibrated to rotate.

[0083] Further, in order to make the calibration board 40 serve as the field of view reference object of the currently calibrated camera, in an optional embodiment, the rotation module 10 can be made to drive the camera on the device 90 to be calibrated to rotate until a complete image of the calibration board 40 appears in the imaging screen of the currently calibrated camera.

[0084] To improve the calibration accuracy, further, the rotation module 10 can also be made to drive the camera on the device 90 to be calibrated to rotate until the field of view center of the currently calibrated camera is aligned with the calibration board 40, so that the image of the calibration board 40 in the imaging screen of the currently calibrated camera is in the central area of the imaging screen.

[0085] The guiding module 20 is connected to the calibration board 40 and is used to move the calibration board 40 in response to the displacement control signal;

[0086] In an optional embodiment, the calibration board 40 can also be moved to a position where the image of the calibration board 40 occupies a preset proportional range of the camera screen captured by the camera to be calibrated. In this way, it can not only ensure that the camera to be calibrated can capture the complete calibration board, but also keep the calibration board presenting a certain proportion in the camera screen. Such a setting can simulate the field of view of a certain reference scene when the camera has an overlapping field of view. In practice, the preset proportional range should not be set too large and can be set between 1 / 16 and 1 / 4.

[0087] Moreover, the edge of the calibration board 40 is at a position that does not exceed the vertical field of view angle range of the radar. Correspondingly, the rotation module 10, the guiding module 20, and the external parameter calibration module 50 can also transmit feedback signals to the control module 30 so that the control module 30 can know the real-time position of the device 90 to be calibrated or the calibration board 40 to judge whether the device 90 to be calibrated or the calibration board 40 is in place.

[0088] Exemplarily, after the rotation module 10 rotates to the target angle, it can transmit a first feedback signal to the control module 30, enabling the control module 30 to determine that the device to be calibrated has completed rotation. The guiding module 20 can transmit a second feedback signal to the control module 30 after the calibration plate 40 moves to the target position, enabling the control module 30 to determine that the calibration plate 40 has completed movement.

[0089] In an alternative implementation, the control module 30 can also send corresponding compensation control signals according to the real-time positions of the device to be calibrated 90 or the calibration plate 40, enabling the device to be calibrated 90 or the calibration plate 40 to reach the target position.

[0090] The external parameter calibration module 50 is configured to respond to the calibration control signal. When the currently to-be-calibrated camera of the device to be calibrated 90 rotates to align with the calibration plate 40 and the imaging screen of this camera includes the calibration plate, it acquires the positioning data of the calibration plate 40 relative to the device to be calibrated 90 and calibrates the external parameters of this camera.

[0091] Among them, the imaging screen of the currently to-be-calibrated camera including the calibration plate can refer to including a complete calibration plate image. Exemplarily, when the distance between the calibration plate and the device to be calibrated is too close, the imaging screen of the currently to-be-calibrated camera does not include the complete calibration plate.

[0092] Among them, considering the need to be compatible with the situation where cameras have no field-of-view overlap, the external parameters of the cameras can be calibrated by means of a position sensing sensor and the calibration plate 40. To achieve fast and accurate positioning, the position sensing sensor can include at least one of the following: radar, infrared ranging device. In the embodiments of the present application, it is considered to integrate the position sensing sensor into the external parameter calibration module 50. For this purpose, the external parameter calibration module 50 can include radar. The radar can transmit radar signals through unobstructed air to the calibration plate 40 and determine the positional relationship between the radar and the calibration plate 40 by receiving the radar signals returned by the calibration plate 40.

[0093] Further, in an alternative implementation, according to the positional relationship between the radar and the calibration plate 40, the positional relationship between the camera enabled in the device to be calibrated 90 and the calibration plate 40 can be determined, thereby calibrating the external parameters of the radar and the camera enabled in the device to be calibrated 90. And according to the external parameters of the radar and the two cameras enabled in the device to be calibrated 90 respectively, the external parameters of these two cameras can be obtained. By this method, the external parameters of all cameras in the device to be calibrated 90 can be obtained.

[0094] Refer to Figure 2 , Figure 2It is a working schematic diagram of an external parameter calibration device for a camera provided by an embodiment of the present application. For the convenience of illustration, the external parameter calibration module 50 located above the device 90 to be calibrated is not shown.

[0095] As Figure 2 shown, through the above embodiment, the present application uses the control module 30 to send signals to control the corresponding devices, including the rotation module 10 and the guiding and moving module 20, to adjust and change the relative angle and relative position between the device 90 to be calibrated and the calibration board 40. The control module 30 can also control the camera and data acquisition to automatically calibrate the external parameters of the camera. Even if there is no overlapping field of view among the cameras, as long as there is a calibration board in the captured image and the position of the calibration board can be determined, then each camera can use the calibration board as a reference object for the unified field of view for calibration. Therefore, it is possible to complete the calibration of the external parameters of multiple cameras without relying on the participation of overlapping fields of view. Therefore, on the one hand, the calibration board 40 is automatically used as a medium for calibration in the embodiment of the present application, and it is not necessary to consider whether there is an overlapping field of view between the cameras. On the other hand, the calibration board 40 is automatically used to calibrate the device 90 to be calibrated at a specific angular position, saving a large number of manual participation links and greatly improving the calibration efficiency and accuracy of the external parameters of the camera.

[0096] In addition, the embodiment of the present application can be applied to the calibration of the external parameters of vehicle-mounted cameras, and it is not required that there is a common viewing area between the vehicle-mounted cameras. While saving camera costs and compressing vehicle space, it reduces the manual participation in the calibration process, is applicable to the calibration of the external parameters of mass-produced vehicle models, and greatly improves the calibration efficiency and accuracy.

[0097] In order to reduce unnecessary losses of the camera and the devices used for calibration during the calibration process, the embodiment of the present application considers rotating the device 90 to be calibrated to the target angle and moving the calibration board 40 to the target position, then turning on the camera, and calibrating the external parameters of the camera of the device 90 to be calibrated through the external parameter calibration module 50. For this purpose, in an optional embodiment, the present application also provides an external parameter calibration device for a camera, wherein,

[0098] The rotation module 10 includes: a first feedback unit for transmitting a first feedback signal to the control module 30 after rotating the device 90 to be calibrated to the target angle.

[0099] Among them, the target angle can be the angle at which the current camera to be calibrated in the device 90 to be calibrated reaches the target viewing angle position. Therefore, the target angle can be the angle at which the current camera to be calibrated in the device 90 to be calibrated rotates to align with the calibration board 40, or the position where the center of the imaging screen of the current camera to be calibrated is exactly opposite to the calibration board 40.

[0100] See Figure 2For example, the cameras of the device 90 to be calibrated may include a plurality of cameras arranged around, specifically including: the first camera 9-1, the second camera 9-2, the third camera 9-3, the fourth camera 9-4, the fifth camera 9-5, and the sixth camera 9-6. Exemplarily, when calibrating the first camera 9-1, in order to obtain the external parameters of the first camera 9-1 and the relay radar 51, the first camera 9-1 can be rotated to a preset direction angle, for example, 30° eastward from the due north direction.

[0101] The guiding and moving module 20 includes: a second feedback unit for transmitting a second feedback signal to the control module 30 after moving the calibration board 40 to the target position.

[0102] Among them, the guiding and moving module 20 can move the calibration board 40 closer to or farther away from the cameras of the device 90 to be calibrated through the guide rail 22. The target position is the position where the cameras of the device 90 to be calibrated can be calibrated. Therefore, the target position can be the position where the calibration board is included in the imaging screen of the current camera to be calibrated.

[0103] The control module 30 includes: a signal acquisition unit for receiving the first feedback signal and the second feedback signal.

[0104] The control module 30 is further configured to transmit a control signal to the external parameter calibration module 50 after the control module 30 receives the first feedback signal and the second feedback signal.

[0105] Among them, the first feedback unit or the second feedback unit can also be connected by signals in the form of a Controller Area Network (CAN) to transmit feedback signals.

[0106] Refer to Figure 3 , Figure 3 is a schematic diagram of the operation of an external parameter calibration module 50 provided by an embodiment of the present application. As Figure 3 shown, the external parameter calibration module 50 in the present application may include a radar to use the radar for calibrating the external parameters of the camera. Exemplarily, it can be a relay radar 51. For this purpose, in an optional embodiment, the present application also provides an external parameter calibration device for a camera, where the external parameter calibration module 50 includes: a relay radar 51.

[0107] The relay radar 51 is arranged on the side of the device 90 to be calibrated away from the rotation module 10, and is configured to respond to the calibration control signal, start and emit radar signals, and receive and collect the positioning data fed back from the calibration board 40 to the position where the device 90 to be calibrated is located.

[0108] Among them, the relay radar 51 can start and emit radar signals after the device 90 to be calibrated rotates to the target angle, the calibration board 40 moves to the target position, and the camera of the device 90 to be calibrated is turned on, and receive and collect the positioning data fed back from the calibration board 40 to the position where the device 90 to be calibrated is located.

[0109] A lidar is a radar system that detects the position, speed and other characteristic quantities of a target by emitting laser beams, and has accurate ranging ability. In order to further improve the calibration accuracy of the relay radar 51 and achieve a calibration range with no dead angles and full coverage, in an alternative embodiment, the relay radar 51 includes: a lidar with a horizontal field of view angle of 360°.

[0110] As Figure 3 shown, in order to prevent the electromagnetic signal of the relay radar 51 from being blocked, the external parameter calibration module 50 may further include a radar base 52 for setting the relay radar 51 above the device 90 to be calibrated, which on the one hand strengthens the fixation of the relay radar 51, and on the other hand improves the field of view of the relay radar 51 and reduces occlusion.

[0111] As Figure 3 shown, in an example provided by the embodiment of the present application, the radar base 52 may be a "ji"-shaped device for placing on the top of the device 90 to be calibrated, and the structure ensures that the edges of the device 90 to be calibrated and the radar base 52 will not block the relay radar 51, and the top of the radar base 52 can be used to fix the relay radar 51.

[0112] In order to improve the timeliness of measurement and the accuracy of data, the embodiment of the present application considers synchronizing the start time or the shutdown time of the camera and the external parameter calibration module 50. For this purpose, in an alternative embodiment, the present application further provides an external parameter calibration device for a camera, wherein the control module 30 includes: a clock synchronization unit; the clock synchronization unit establishes a signal connection with the camera of the device 90 to be calibrated and the external parameter calibration module 50.

[0113] The clock synchronization unit is used to synchronize the start or shutdown time of the external parameter calibration module 50 and the current camera to be calibrated by transmitting a synchronous clock signal to the current camera to be calibrated of the device 90 to be calibrated and the external parameter calibration module 50.

[0114] Among them, the clock synchronization unit can cooperate with the device control unit to transmit the synchronous clock signal to the device control unit and the external parameter calibration module 50, so that the camera and the relay radar 51 are started or shut down synchronously.

[0115] To facilitate the automatic completion of calibration, reduce manual intervention, and improve the calibration efficiency, the control unit of the camera of the device 90 to be calibrated can also be integrated into the control module 30 in the embodiments of the present application. For this purpose, in an alternative embodiment, the present application also provides an external parameter calibration device for a camera, wherein the control module 30 includes: a device control unit; the device control unit establishes a signal connection with the camera of the device 90 to be calibrated.

[0116] The device control unit is configured to transmit a control signal to the currently to-be-calibrated camera of the device 90 after the control module 30 receives the first feedback signal and the second feedback signal, so as to control the currently to-be-calibrated camera of the device 90 to turn on.

[0117] In an alternative embodiment, the present application can set the calculation unit for external parameter calibration data in the control module 30 to improve the integration efficiency of the calculation.

[0118] Considering that in the embodiments of the present application, it is necessary to calculate the external parameters between each camera and the radar, which involves multiple operations and data transmission. To solve the problem of low efficiency caused by a large amount of data transmission between the radar and the calculation unit, the embodiments of the present application can also consider setting the calculation unit in the external parameter calibration module 50. For this purpose, in another alternative embodiment, the present application also provides an external parameter calibration device for a camera, wherein the external parameter calibration module 50 further includes:

[0119] The first external parameter calculation unit is configured to obtain the external parameters between the relay radar 51 and any one of the cameras of the device 90 to be calibrated according to the positioning data.

[0120] The second external parameter calculation unit is configured to obtain the external parameters between any two cameras of the device 90 to be calibrated according to the external parameters between the relay radar 51 and any two cameras of the device 90 to be calibrated.

[0121] Refer to Figure 4 , Figure 4 is a schematic structural diagram of a guiding and moving module 20 provided by the embodiments of the present application. As Figure 4 shown, taking an intelligent vehicle as an example, considering that the devices 90 to be calibrated mostly perform calibration by horizontal rotation, the embodiments of the present application provide a rotating table 11 for placing and fixing the device 90 to be calibrated, and move the calibration plate 40 in the form of a guide rail 22. For this purpose, in an alternative embodiment, the present application also provides an external parameter calibration device for a camera, wherein the rotating module 10 includes: a rotating table 11 for fixing and driving the device 90 to be calibrated to rotate.

[0122] The guiding and moving module 20 includes: a calibration bracket 21 and a guide rail 22, and the calibration bracket 21 is used for fixing and driving the calibration plate 40 to move along the track direction of the guide rail 22.

[0123] Among them, the straight line along the track direction of the guide rail 22 passes through the rotary table 11.

[0124] Among them, the guide rail 22 can be a radial guide rail 22 that is close to or far from the rotary table 11. Among them, in order to improve the calibration accuracy, the extension line of the track where the radial guide rail 22 is located can pass through the center of the rotary table 11.

[0125] Among them, in order to make the calibration plate 40 image in the imaging screen of the camera to be calibrated currently be in the central area of the imaging screen, the calibration bracket 21 can also be used to raise or lower the calibration plate 40 so that the center height of the calibration plate 40 is flush with the height of the camera to be calibrated currently.

[0126] Furthermore, in order to perform omnidirectional calibration of the camera of the device 90 to be calibrated, it is necessary to rotate the device 90 to be calibrated omnidirectionally. For this purpose, in an optional implementation manner, the present application also provides an external parameter calibration device for a camera, where the rotary table 11 further includes:

[0127] A first device rotation unit for driving the device 90 to be calibrated to rotate along a first rotation axis;

[0128] A second device rotation unit for driving the device 90 to be calibrated to rotate along a second rotation axis;

[0129] Among them, the first rotation axis and the second rotation axis intersect and are perpendicular to each other.

[0130] The embodiment of the present application also considers adjusting the angular position between the device 90 to be calibrated and the calibration plate 40 by rotating the calibration plate 40. For this purpose, in another optional implementation manner, the present application also provides an external parameter calibration device for a camera, where the calibration bracket 21 further includes:

[0131] A first calibration rotation unit for driving the calibration plate 40 to rotate along a third rotation axis;

[0132] A second calibration rotation unit for driving the calibration plate 40 to rotate along a fourth rotation axis;

[0133] Among them, the third rotation axis and the fourth rotation axis intersect and are perpendicular to each other.

[0134] Refer to Figure 5 , Figure 5 is a schematic structural diagram of a positioning mark 12 provided by the embodiment of the present application. As Figure 5 shown, in order to facilitate the precise positioning of the device 90 to be calibrated, in an optional implementation manner, the present application also provides an external parameter calibration device for a camera, where the rotary table 11 further includes:

[0135] The positioning mark 12 is directly opposite to the intersection of the first rotation axis and the second rotation axis, and is used to position the device 90 to be calibrated. Among them, the positioning mark 12 can be a hollow mark or a coating mark on the surface of the turntable 11.

[0136] Furthermore, the intersection of the first rotation axis and the second rotation axis can be directly opposite to the center of the turntable 11. Thus, the geometric center of the positioning mark 12 can coincide with the center of the turntable 11.

[0137] Refer to Figure 6 , Figure 6 is a flowchart of the steps of an external parameter calibration method for a camera provided by an embodiment of the present application. As Figure 6 shown, an embodiment of the present application provides an external parameter calibration method for a camera, which can be executed by the external parameter calibration device of the camera in any of the above embodiments. The method specifically includes the following steps:

[0138] Step S61, the control module 30 transmits a rotation control signal to the rotation module 10, and transmits a displacement control signal to the guiding and moving module 20.

[0139] Step S62, the rotation module 10 rotates in response to the rotation control signal to drive the device 90 to be calibrated to rotate.

[0140] Step S63, the guiding and moving module 20 moves the calibration plate 40 in response to the displacement control signal.

[0141] Step S64, determine whether the currently calibrated camera of the device 90 to be calibrated is aligned with the calibration plate 40, and determine whether the imaging screen of the camera includes the calibration plate 40.

[0142] Step S65, when the currently calibrated camera of the device 90 to be calibrated rotates to be aligned with the calibration plate 40 and the imaging screen of the camera includes the calibration plate 40, the control module 30 transmits a calibration control signal to the external parameter calibration module 50.

[0143] Step S66, the external parameter calibration module 50 obtains the positioning data of the calibration plate 40 relative to the device 90 to be calibrated in response to the calibration control signal, and calibrates the external parameters of the camera based on the positioning data.

[0144] Through the above embodiments, the external parameter calibration method for a camera provided by the present application collects the positioning data of the camera of the device 90 to be calibrated after the device 90 to be calibrated and the calibration plate 40 reach the target set positions and angles, and performs external parameter calibration of the camera of the device 90 to be calibrated according to the positioning data of the camera of the device 90 to be calibrated.

[0145] Refer to Figure 7 , Figure 7This is a flowchart of the steps of a method for determining an image of a calibration board in an imaging screen provided by an embodiment of the present application. As Figure 7 shown, in order to accurately calibrate using the image of the calibration board 40 in the camera imaging, in an optional embodiment, the present application also provides a method for determining an image of a calibration board in an imaging screen, including:

[0146] Step S71, start the currently to-be-calibrated camera 90 and obtain the imaging screen.

[0147] Step S72, capture the image of the calibration board 40 in the imaging screen of the currently to-be-calibrated camera through a preset image detection algorithm.

[0148] Among them, the preset image detection algorithm can be an artificial neural network algorithm based on deep learning. The image detection algorithm has been maturely applied in various technical fields and will not be elaborated here.

[0149] Step S73, determine whether the imaging screen of this camera includes the calibration board 40.

[0150] Step S74, in the case that the imaging screen of this camera includes the calibration board 40, detect the shooting angle of the calibration board 40 through a preset image detection algorithm to determine whether the currently to-be-calibrated camera of the to-be-calibrated device 90 is aligned with the calibration board 40.

[0151] Among them, when the shooting angle of the calibration board is 0°, the image of the calibration board in the imaging screen has no skew, indicating that the plane of the calibration board is facing the currently to-be-calibrated camera, that is, it is aligned with the currently to-be-calibrated camera of the to-be-calibrated device.

[0152] Further, in an optional embodiment, the present application also provides a method for determining whether an imaging screen of a camera includes a calibration board, including:

[0153] Judge whether the image of the calibration board meets the preset conditions through a preset image detection algorithm; the preset conditions include that the image of the calibration board is complete, and the proportion of the area occupied by the image of the calibration board in the imaging screen is within a preset proportion range;

[0154] If so, determine that the imaging screen of this camera includes the calibration board.

[0155] As described above, the preset proportion range can be greater than 1 / 16 and less than 1 / 4. Specifically, when calibrating the external parameters of each to-be-calibrated camera, the images of the calibration board in the camera screens captured by them all meet this preset condition.

[0156] Further, to ensure the integrity of the located data, it is also possible to use radar to determine whether the edge of the calibration board is within the vertical field of view angle range of the radar. If so, the positioning data of the calibration board relative to the device to be calibrated can be obtained.

[0157] Optionally, to improve the calibration efficiency, before performing the above external parameter calibration method for the camera, the following steps can also be executed:

[0158] Initialize the calibration environment, including:

[0159] Place the device to be calibrated 90 at the positioning mark 12 at the center of the rotary table 11. Fix the radar base 52 with the relay radar 51 installed in the external parameter calibration module 50 above the device to be calibrated 90. The control module 30 transmits digital signals to control the rotary table 11 in the rotation module 10 to rotate to a preset angle range, and to control the guiding and moving module 20 to move the calibration bracket 21 to a preset position range; turn off the radar and all cameras in the external parameter calibration module 50.

[0160] For the calibration of the vehicle's camera, the present application also provides an example of initializing the calibration environment:

[0161] Place the vehicle to be calibrated at the positioning mark 12 at the center of the rotary table 11. Place the radar base 52 with the relay radar 51 fixed on the top of the vehicle to be calibrated. Send digital signals through the console frame to control the rotary table 11, the calibration bracket 21, and the calibration board 40 to appropriate positions; turn off the relay radar 51 and all vehicle-mounted cameras.

[0162] In the above embodiment, through initialization, the calibration bracket 21 and the calibration board 40 in the rotation module 10 and the guiding and moving module 20 are moved to a preset position range or angle range. To further improve the calibration efficiency, the present application embodiment also provides an example of initializing the calibration environment:

[0163] According to the position of the first calibrated camera, the control module 30 transmits a control signal to rotate the rotary table 11 to a preset initial angle, so that the first calibrated camera faces the guide rail 22 in the guiding and moving module 20;

[0164] The control module 30 transmits a control signal to control the calibration bracket 21 to move the calibration plate 40 along the guide rail 22 to a preset initial position, and adjust the height of the calibration plate 40 to ensure that the calibration plate 40 faces the first calibrated camera, so that the image of the calibration plate 40 in the imaging screen of the first calibrated camera is in the central area of the imaging screen. Specifically, the imaging screen of the calibration plate 40 can occupy a certain proportion of the camera screen captured by the camera to be calibrated. For example, the image of the calibration plate 40 occupies an area of 1 / 16 to 1 / 4 of the imaging screen, which can better simulate the overlapping field of view between cameras, and the edge of the calibration plate 40 does not exceed the vertical field of view angle range of the lidar.

[0165] Correspondingly, for the calibration of the vehicle camera, the present application also provides an example of the external parameter calibration of the camera:

[0166] A signal connection is established between the console frame and the controlled device through a network cable or a wireless network. Among them, the controlled device includes: a turntable 11, a calibration bracket 21 on the guide rail 22, and an in-vehicle camera.

[0167] Among them, the console frame can be used to send a control signal to control the turntable 11 to rotate at any angle, and can also be used to control the calibration plate 40 to rotate horizontally or vertically within a preset range through the calibration rotation unit in the calibration bracket 21 on the guide rail 22; among them, the feedback plane of the calibration plate 40 always faces the turntable 11.

[0168] The console frame can also be used to control the calibration bracket 21 to move bidirectionally along the guide rail 22.

[0169] The console frame can also be used to control the switch of the relay radar 51 and the in-vehicle camera to collect the positioning data returned by the calibration plate 40.

[0170] Further, in an optional implementation manner, the present application also exemplarily provides a method for collecting positioning data:

[0171] The console frame transmits a control signal to control the rotation of the turntable 11 so that the field of view of the first camera 9-1 of the device 90 to be calibrated covers the calibration plate 40, turns on the relay radar 51 and the first camera 9-1, and the console frame sends a digital quantity signal to control the rotation of the calibration plate 40 so that the signal feedback surface of the calibration plate 40 faces the turntable 11, and collects the first set of positioning data. After the collection is completed, the relay radar 51 and the first camera 9-1 are turned off;

[0172] The console frame controls the rotation of the turntable 11 so that the field of view of the second camera 9-2 of the device 90 to be calibrated covers the calibration plate 40, turns on the relay radar 51 and the second camera 9-2, and collects the second set of positioning data. After the collection is completed, the relay radar 51 and the second camera 9-2 are turned off.

[0173] Collect the positioning data of the relay radar 51 and other cameras simultaneously in sequence until the positioning data of all cameras to be calibrated are collected. Each set of positioning data corresponds to one camera.

[0174] Further, in an optional implementation manner, the present application also exemplarily provides a method for external parameter calibration:

[0175] Calibrate the first relay external parameter between the relay radar 51 and the first camera 9-1 according to the first set of positioning data;

[0176] Calibrate the second relay external parameter between the relay radar 51 and the second camera 9-2 according to the second set of positioning data;

[0177] Obtain the external parameter between the first camera 9-1 and the second camera 9-2 according to the first relay external parameter and the second relay external parameter.

[0178] Execute the method provided in the above embodiments in sequence, and the external parameter between any two cameras in the device 90 to be calibrated can be obtained. Thus, the external parameters of all cameras can be further obtained. Compared with the prior art, the method for calibrating the external parameters of cameras provided in the embodiments of the present application has the following advantages:

[0179] (1) Based on the external parameter calibration device of the camera provided in the embodiments of the present application, using the calibration board 40 as a relay medium, it breaks the condition limitation of the need for overlapping fields of view in the multi-camera calibration process;

[0180] (2) Based on the external parameter calibration device of the camera provided in the embodiments of the present application, there are no special requirements for the placement position of the calibration board 40, the angular position of the device 90 to be calibrated, etc. The calibration result does not depend on a high-precision calibration environment, reducing the calibration cost;

[0181] (3) The calibration device centered on the rotation module 10 and the control module 30 involved in the embodiments of the present application greatly reduces the requirement for manual participation after the initialization of the calibration environment is completed, meets the timeliness requirement for the calibration of the device 90 to be calibrated, and greatly improves the efficiency of calibrating the external parameters of the camera.

[0182] Based on the same inventive concept, another embodiment of the present application provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the method in any of the above embodiments of the present application.

[0183] Based on the same inventive concept, another embodiment of the present application also provides an electronic device. The electronic device includes a memory, a processor, and a computer program stored on the memory and running on the processor. When the processor executes, it implements the steps of the method in any of the above embodiments of the present application.

[0184] Each embodiment in this specification is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0185] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, devices, or computer program products. Therefore, the embodiments of the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0186] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (devices), 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, as well as the combination of 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 the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0187] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0188] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, such that a series of operation steps are executed on the computer or other programmable terminal device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable terminal device provide steps for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0189] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0190] Finally, it should also be noted that in this embodiment, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0191] The above has introduced in detail an external parameter calibration device for a camera and an external parameter calibration method for a camera provided by the present application. In this embodiment, specific examples are used to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. An external parameter calibration device for a camera, characterized in that, include: A rotation module, a guide module, a control module, a calibration plate, and an external parameter calibration module; wherein the control module establishes signal connections with the rotation module, the guide module, and the external parameter calibration module respectively; The control module is used to transmit a rotation control signal to the rotation module, and to transmit a displacement control signal to the guide module, and also to transmit a calibration control signal to the external parameter calibration module; The rotation module is connected to the device to be calibrated and is used to rotate in response to the rotation control signal to drive the device to be calibrated to rotate; The guide module is connected to the calibration plate and is used to move the calibration plate in response to the displacement control signal; The external parameter calibration module is used to respond to the calibration control signal, and when the current camera to be calibrated of the device to be calibrated is rotated to be aligned with the calibration plate and the imaging picture of the camera includes the calibration plate, obtain the positioning data of the calibration plate relative to the device to be calibrated, and calibrate the external parameters of the camera based on the positioning data.

2. The external parameter calibration device for a camera according to claim 1, characterized in that, The rotation module comprises: a first feedback unit, configured to transmit a first feedback signal to the control module after rotating the device to be calibrated to a target angle; The guide module includes: a second feedback unit, which is used to transmit a second feedback signal to the control module after moving the calibration plate to the target position; The control module includes: a signal acquisition unit, configured to receive the first feedback signal and the second feedback signal; The control module is further configured to transmit the control signal to the external parameter calibration module after receiving the first feedback signal and the second feedback signal.

3. The external parameter calibration device for a camera according to claim 1, characterized in that, The external parameter calibration module includes: a relay radar; The relay radar is arranged on a side of the device to be calibrated away from the rotating module, and is used to respond to the calibration control signal, start and send out radar signals, and receive and collect the positioning data fed back from the calibration board to the location of the device to be calibrated.

4. The external parameter calibration device for a camera according to claim 1, characterized in that, The control module includes: a clock synchronization unit; the clock synchronization unit establishes a signal connection with the camera of the device to be calibrated and the external parameter calibration module; The clock synchronization unit is used to synchronize the start or shut down time of the external parameter calibration module with the current camera to be calibrated of the device to be calibrated by transmitting a synchronization clock signal to the current camera to be calibrated and the external parameter calibration module.

5. The external parameter calibration device for a camera according to claim 1, characterized in that, The control module includes: a device control unit; the device control unit establishes a signal connection with the camera of the device to be calibrated; The device control unit is used to transmit the control signal to the current camera to be calibrated of the device to be calibrated after the control module receives the first feedback signal and the second feedback signal, so as to control the current camera to be calibrated of the device to be calibrated to start.

6. The external parameter calibration device for a camera according to claim 3, characterized in that, The external parameter calibration module also includes: A first external parameter calculation unit, used for obtaining an external parameter between the relay radar and any camera in the device to be calibrated according to the positioning data; A second external parameter calculation unit, configured to obtain the external parameters between any two cameras in the device to be calibrated according to the external parameters between the relay radar and any two cameras in the device to be calibrated.

7. The external parameter calibration device for a camera according to claim 1, characterized in that, The rotation module includes: a rotating table, configured to fix and drive the device to be calibrated to rotate; The guiding and moving module includes: a calibration bracket and a guide rail, where the calibration bracket is configured to fix and drive the calibration board to move along the track direction of the guide rail; Wherein, the straight line along the track direction of the guide rail passes through the rotating table.

8. The external parameter calibration device for a camera according to claim 6, characterized in that, The rotating table further includes: A first device rotation unit, configured to drive the device to be calibrated to rotate along a first rotation axis; A second device rotation unit, configured to drive the device to be calibrated to rotate along a second rotation axis; A positioning mark, facing the intersection of the first rotation axis and the second rotation axis, configured to position the device to be calibrated; Wherein, the first rotation axis and the second rotation axis intersect and are perpendicular to each other.

9. The external parameter calibration device for a camera according to claim 6, characterized in that, The calibration bracket further includes: A first calibration rotation unit, configured to drive the calibration board to rotate along a third rotation axis; A second calibration rotation unit, configured to drive the calibration board to rotate along a fourth rotation axis; Wherein, the third rotation axis and the fourth rotation axis intersect and are perpendicular to each other.

10. A method for calibrating the external parameters of a camera, characterized in that, It includes: The control module transmits a rotation control signal to the rotation module, and transmits a displacement control signal to the guiding and moving module; The rotation module rotates in response to the rotation control signal to drive the device to be calibrated to rotate; The guiding and moving module moves the calibration board in response to the displacement control signal; Judge whether the currently calibrated camera of the device to be calibrated is aligned with the calibration board, and judge whether the imaging screen of this camera includes the calibration board; When the currently calibrated camera of the device to be calibrated rotates to be aligned with the calibration board and the imaging screen of this camera includes the calibration board, the control module transmits a calibration control signal to the external parameter calibration module; The external parameter calibration module, in response to the calibration control signal, acquires the positioning data of the calibration board relative to the device to be calibrated, and calibrates the external parameters of this camera based on the positioning data.

11. The method for calibrating the external parameters of a camera according to claim 10, characterized in that, The step of judging whether the currently calibrated camera of the device to be calibrated is aligned with the calibration board, and judging whether the imaging screen of this camera includes the calibration board includes: Start the currently calibrated camera to acquire an imaging screen; Grab the image of the calibration board in the imaging screen of the currently calibrated camera through a preset image detection algorithm; Judge whether the imaging screen of this camera includes the calibration board; When the imaging screen of this camera includes the calibration board, detect the shooting angle of the calibration board through the preset image detection algorithm to judge whether the currently calibrated camera of the device to be calibrated is aligned with the calibration board.

12. The method for calibrating the external parameters of a camera according to claim 11, characterized in that, The step of judging whether the imaging screen of this camera includes the calibration board includes: Judge whether the image of the calibration board meets a preset condition through the preset image detection algorithm; the preset condition includes that the image of the calibration board is complete, and the proportion of the area occupied by the image of the calibration board in the imaging screen is within a preset proportion range; If so, it is determined that the imaging screen of the camera includes the calibration board.

Images