Camera calibration method, system, device and equipment

Abstract

This application discloses a camera calibration method, system, device, and equipment, belonging to the field of automotive design technology, which can solve the problem of low calibration efficiency for cameras. The method includes: receiving pressure signals from the wheels via a pressure sensor when a vehicle is detected to have traveled to a preset position; determining the coordinates of the vehicle's wheel positions based on the pressure signals; determining the vehicle's outline position based on the wheel position coordinates; displaying a calibration pattern around the vehicle based on the outline position; and calibrating the vehicle's camera using the calibration pattern to obtain the camera's external parameters.

Description

Technical Field

[0001] This application belongs to the field of automotive design technology, specifically relating to a camera calibration method, system, device, and equipment. Background Technology

[0002] During driving, cameras are needed to capture surrounding road conditions, and the accuracy of these cameras is crucial. Generally, camera parameters are obtained through calibration. In existing technology, camera calibration involves displaying calibration patterns on a calibration board, which the camera then identifies to complete the calibration.

[0003] In existing technologies, the process of calibrating images is quite cumbersome, requiring manual determination of the display position of each image before display. Summary of the Invention

[0004] The purpose of this application is to provide a camera calibration method, system, apparatus, and device that can solve the problem of low calibration efficiency for cameras.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application provide a camera calibration method, which is applied to a computing unit in a camera calibration system, including: When the vehicle is detected to have moved to a preset position, the pressure signal of the wheel is received by the pressure sensor; Based on the pressure signal, determine the coordinates of the vehicle's wheel position; The outline position of the vehicle is determined based on the coordinates of the wheel positions; Based on the outline position, a calibration pattern is displayed around the vehicle; The vehicle's camera is calibrated using the calibration pattern to obtain the camera's external parameters.

[0006] Optionally, determining the wheel position information of the vehicle based on the pressure signal includes: The pressure value applied to the sensor is determined based on the pressure signal. The coordinates of the vehicle's wheel position are determined based on the pressure value received by the sensor and the sensor's position coordinates.

[0007] Optionally, determining the wheel position coordinates of the vehicle based on the pressure value received by each sensor and the position coordinates of the sensor includes: The horizontal coordinate of the vehicle's wheel position is determined based on the pressure value received by the sensor and the horizontal coordinate of the sensor's position coordinates. The ordinate of the vehicle's wheel position is determined based on the pressure value received by the sensor and the ordinate of the sensor's position coordinates. The coordinates of the center point of the wheel are used as the wheel position coordinates of the vehicle.

[0008] Optionally, determining the vehicle's outline position based on the coordinates of the wheel positions includes: The vehicle model data is retrieved, including the front overhang distance, rear overhang distance, vehicle width, and vehicle length. Based on the vehicle model data, determine the outline size of the vehicle; The outline position of the vehicle is determined based on the position coordinates of the wheels and the outline size of the vehicle.

[0009] Optionally, displaying a calibration pattern around the vehicle based on the contour position includes: Obtain the location information of the vehicle's camera on the vehicle body and the pattern parameters of the calibration pattern from the database; The display position of the calibration pattern is determined based on the outline position, the position information, and the pattern parameters. The calibration pattern is displayed at the display position via a display device.

[0010] Optionally, determining the display position of the calibration pattern based on the contour position, the position information, and the pattern parameters includes: The shooting range of the camera is determined based on the outline position and the position information; Based on the pattern parameters, determine the arrangement and size of the calibration pattern; Based on the arrangement and size of the calibration pattern, select a coordinate point within the camera's shooting range as the display position of the calibration pattern.

[0011] Optionally, calibrating the vehicle's camera using the calibration pattern to obtain the camera's external parameters includes: The calibration pattern is captured by the camera to obtain the captured image; Corner detection is performed on the acquired image to determine the coordinates of the first corner point corresponding to the acquired image; Obtain the coordinates of the second corner point of the calibration pattern in the vehicle coordinate system; By matching the coordinates of the first corner point with the coordinates of the second corner point, the corresponding point pairs are obtained; The external parameters of the camera are obtained by using the coordinate difference between the point pairs.

[0012] Secondly, embodiments of this application provide a camera calibration system, the system comprising: A pressure sensor is installed on the ground to obtain the pressure value of the wheel on the ground. A display device for displaying a calibration pattern on the ground is mounted above the pressure sensing device; A transparent protective device is installed above the display device to protect it from damage caused by wheel pressure. The computing unit is used to perform any step in the camera calibration method provided in the first aspect of the embodiments of this application; Storage units are used to store data generated during system operation.

[0013] Thirdly, embodiments of this application provide a camera calibration device, which includes: The pressure signal receiving module is used to receive the pressure signal of the wheels through the pressure sensor when the vehicle is detected to have traveled to a preset position. A wheel position determination module is used to determine the coordinates of the vehicle's wheel position based on the pressure signal. The contour position determination module is used to determine the contour position of the vehicle based on the coordinates of the wheel positions. A calibration pattern display module is used to display a calibration pattern around the vehicle according to the outline position; The camera calibration module is used to calibrate the vehicle's camera using the calibration pattern to obtain the camera's external parameters.

[0014] Optionally, the wheel position determination module includes: The pressure value determination submodule is used to determine the pressure value received by the sensor based on the pressure signal; The wheel coordinate determination submodule is used to determine the coordinates of the vehicle's wheel position based on the pressure value received by the sensor and the sensor's position coordinates.

[0015] Optionally, the wheel coordinate determination submodule includes: The first coordinate determination submodule is used to determine the abscissa of the vehicle's wheel position based on the pressure value received by the sensor and the abscissa in the sensor's position coordinates. The second coordinate determination submodule is used to determine the ordinate of the vehicle's wheel position based on the pressure value received by the sensor and the ordinate in the sensor's position coordinates. The third coordinate determination submodule is used to use the coordinates of the center point of the wheel as the wheel position coordinates of the vehicle.

[0016] Optionally, the contour position determination module includes: The vehicle model data retrieval submodule is used to retrieve the vehicle model data, which includes the front overhang distance, rear overhang distance, vehicle width, and vehicle length. The outline size determination submodule is used to determine the outline size of the vehicle based on the vehicle model data; The contour position determination submodule is used to determine the contour position of the vehicle based on the position coordinates of the wheels and the contour size of the vehicle.

[0017] Optionally, the calibration pattern display module includes: The pattern parameter determination submodule is used to obtain the position information of the vehicle's camera on the vehicle body and the pattern parameters of the calibration pattern from the database; The display position determination submodule is used to determine the display position of the calibration pattern based on the outline position, the position information, and the pattern parameters. The calibration pattern display submodule is used to display the calibration pattern at the display position via a display device.

[0018] Optionally, the display position determination submodule includes: The shooting range determination submodule is used to determine the shooting range of the camera based on the contour position and the position information; The layout size determination submodule is used to determine the layout and size of the calibration pattern based on the pattern parameters; The display position acquisition submodule is used to select coordinate points within the shooting range of the camera as the display position of the calibration pattern based on the arrangement and size of the calibration pattern.

[0019] Optionally, the camera calibration module includes: The image acquisition submodule is used to acquire an image of the calibration pattern through the camera to obtain the acquired image; The corner detection submodule is used to perform corner detection on the acquired image and determine the coordinates of the first corner corresponding to the acquired image; The corner point acquisition submodule is used to acquire the coordinates of the second corner point of the calibration pattern in the vehicle coordinate system. The corner matching submodule is used to perform point-to-point matching using the coordinates of the first corner point and the coordinates of the second corner point to obtain the corresponding point pairs; The external parameter determination submodule is used to obtain the external parameters of the camera by the coordinate difference of the point pair.

[0020] Fourthly, embodiments of this application provide an electronic device including a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the method described in the first aspect.

[0021] Fifthly, embodiments of this application provide a readable storage medium on which a program or instructions are stored, which, when executed by a processor, implement the steps of the method described in the first aspect.

[0022] In a sixth aspect, embodiments of this application provide a chip, the chip including a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run programs or instructions to implement the method as described in the first aspect.

[0023] In the camera calibration method provided in this application, when a vehicle is detected to have traveled to a preset position, a pressure signal from the wheel is received by a pressure sensor; the coordinates of the wheel position of the vehicle are determined based on the pressure signal; the outline position of the vehicle is determined based on the coordinates of the wheel position; a calibration pattern is displayed around the vehicle based on the outline position; and the camera of the vehicle is calibrated using the calibration pattern to obtain the external parameters of the camera.

[0024] In this method, when calibrating the camera, the position of the wheel is determined by a pressure sensor, and then the size of the vehicle's outline is determined. The calibration pattern is then automatically displayed around the vehicle to achieve camera calibration. This method automates the camera calibration process, improves camera calibration efficiency, and saves manpower and resources. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the calibration room structure proposed in one embodiment of this application; Figure 2 This is a schematic diagram of the calibration system structure proposed in one embodiment of this application; Figure 3 This is a schematic diagram of a calibration pattern proposed in an embodiment of this application; Figure 4 This is a flowchart of a camera calibration method proposed in an embodiment of this application; Figure 5 This is a top view of the calibration room according to an embodiment of this application; Figure 6 This is a schematic diagram of a sensor proposed in one embodiment of this application; Figure 7 This is a schematic diagram of wheel pressure according to an embodiment of this application; Figure 8This is a schematic diagram of the vehicle outline according to an embodiment of this application; Figure 9 This is a schematic diagram of the calibration pattern display according to an embodiment of this application; Figure 10 This is a schematic diagram of a camera calibration process according to an embodiment of this application; Figure 11 This is a schematic diagram of a camera calibration device according to an embodiment of this application; Figure 12 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0026] 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 some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0028] refer to Figure 1 , Figure 1 This is a schematic diagram of the calibration room structure proposed in one embodiment of this application, as shown below. Figure 1 As shown, the calibration room is a room specifically for calibrating automotive cameras. The floor of the calibration room is equipped with a pressure sensor to locate the vehicle's position using pressure signals. The pressure sensor is equipped with a display device to display calibration patterns. The top layer is a transparent protective device to protect the display device from damage by the vehicle.

[0029] refer to Figure 2 , Figure 2 This is a schematic diagram of the calibration system structure proposed in one embodiment of this application, as shown below. Figure 2As shown, the transparent protective device is made of high-strength, high-transmittance material, effectively protecting the display device from damage caused by wheel pressure. Simultaneously, this device possesses excellent transmission performance, ensuring clear transmission of displayed information. The display device can display specific calibration patterns, boasting high-resolution display capabilities and clearly showcasing the calibration patterns. It is installed on the floor of the calibration room. The pressure sensing device, by sensing the pressure distribution of the wheels on the ground, can accurately determine the specific positions of the four wheels. This device features high sensitivity and high precision, ensuring accurate measurement of wheel positions. It is also installed on the floor of the calibration room. The computing unit is responsible for receiving and processing data from the pressure sensing device, calculating the vehicle center point coordinates based on wheel positioning, the location of the vehicle camera, and vehicle dimensions, and sending instructions to the display device based on the calculation results to control the display position of the calibration pattern. The storage unit stores various data generated during system operation, including wheel positioning information, calibration pattern parameters, and recognition programs, ensuring data integrity and traceability.

[0030] refer to Figure 3 , Figure 3 This is a schematic diagram of a calibration pattern proposed in an embodiment of this application, as shown below. Figure 3 As shown, a calibration pattern is displayed around the car, and the camera on the vehicle collects the data for camera calibration.

[0031] refer to Figure 4 , Figure 4 This is a flowchart of a camera calibration method proposed in an embodiment of this application, as shown below. Figure 4 As shown, this method is applied to the computing unit of a camera calibration system, and specifically includes the following steps: S11: When the vehicle is detected to have moved to a preset position, the pressure signal of the wheel is received by the pressure sensor.

[0032] In this embodiment, there is a general position range within the vehicle's calibration chamber. When the vehicle is parked within this preset position range, the pressure sensor in the calibration chamber receives signals from the wheels.

[0033] For example, the preset location is within a 5m radius of the center point of the calibration room floor. The specific range can be adjusted according to the size of the vehicle model being tested.

[0034] refer to Figure 5 , Figure 5 This is a top view of the calibration room according to an embodiment of this application, as shown below. Figure 5 As shown, after the vehicle enters the calibration room, it stops at the preset position. The vehicle can be parked in the central area of ​​the calibration field in a non-centered and non-perpendicular direction. It is necessary to ensure that there is sufficient space around the vehicle to display the calibration pattern.

[0035] S12: Determine the coordinates of the vehicle's wheel position based on the pressure signal.

[0036] In this embodiment, after obtaining the pressure signal of each wheel, the pressure values ​​of several sensors near the wheel are determined for each wheel, and then the coordinates of the wheel position are determined based on the position coordinates of each sensor.

[0037] For example, the coordinates of the wheel's position are calculated based on pressure signals from four sensors around the wheel.

[0038] S13: Determine the outline position of the vehicle based on the coordinates of the wheel positions.

[0039] In this embodiment, after determining the wheel position coordinates, the relevant data of the detected vehicle is retrieved from the database to determine the dimensions of each part of the vehicle, thereby obtaining the overall outline size of the vehicle and determining the outline position.

[0040] For example, the database stores relevant data for each vehicle model, and the database is used to query specific vehicle information based on each vehicle model.

[0041] S14: Display a calibration pattern around the vehicle according to the outline position.

[0042] In this embodiment, the calibration pattern is a pattern used for camera calibration.

[0043] In this embodiment, after determining the vehicle's outline position, the location of the camera on the vehicle body is determined based on relevant vehicle information. Then, the size parameters of the calibration pattern are determined, leading to the determination of the display position of the calibration pattern. After determining the display position, the corresponding position information is sent to the display device, which then displays the calibration pattern at the corresponding position based on this information. It is necessary to ensure that the calibration pattern is within the camera's field of view.

[0044] For example, the parameters of the calibration pattern are pre-stored in the database. When the calculation unit performs calculations, it retrieves the size information of the calibration pattern from the database and then determines the display position of the calibration pattern based on the size information of the calibration pattern and the position information of the vehicle's camera.

[0045] S15: The vehicle's camera is calibrated using the calibration pattern to obtain the camera's external parameters.

[0046] In this embodiment, the external parameters of the camera include a rotation matrix R, which describes the rotation of the camera coordinate system relative to the world coordinate system. It is typically a 3×3 matrix composed of three rotation angles (ω, δ, θ) around the X, Y, and Z axes. The translation vector T describes the translation of the origin of the camera coordinate system relative to the origin of the world coordinate system, and includes translation components (Tx, Ty, Tz) along the X, Y, and Z directions.

[0047] In this embodiment, after displaying the calibration pattern, the vehicle's camera is activated to capture the calibration pattern. The captured image is then identified to determine the corner coordinates. The corner coordinates of the calibration pattern in the vehicle coordinate system have been pre-stored in the database. The original corner coordinates are retrieved from the database and compared with the identified corner coordinates in the image to obtain the difference. The external parameters of the camera are then derived based on the difference.

[0048] For example, the camera is a surround-view fisheye camera, an ultra-wide-angle surveillance device. Through its unique fisheye lens design, it can achieve a monitoring angle approaching or exceeding 180°, thus covering a wide field of view that traditionally requires multiple cameras with a single camera. It is particularly suitable for scenarios requiring 360° surveillance without blind spots. For calibration, calibration patterns need to be displayed in the area surrounding the vehicle.

[0049] In this embodiment, when calibrating the vehicle camera, after the vehicle drives to the calibration room, the vehicle position is determined by a pressure sensor, and then a calibration pattern is displayed around the vehicle by a display device. The camera is then used to collect the calibration pattern and perform camera calibration, thus realizing an automated camera calibration process and improving camera calibration efficiency.

[0050] In another embodiment of this application, determining the wheel position information of the vehicle based on the pressure signal includes: S21: Determine the pressure value applied to the sensor based on the pressure signal.

[0051] In this embodiment, the pressure signal includes signals such as current, voltage, and digital signals sent by the sensor that reflect the pressure applied to the sensor.

[0052] In this embodiment, after receiving the pressure signal, the pressure value received by the sensor is determined based on the pressure signal.

[0053] refer to Figure 6 , Figure 6 This is a schematic diagram of a sensor proposed in an embodiment of this application, as shown below. Figure 6 As shown, pressure sensors are evenly arranged in the calibration chamber.

[0054] For example, if the output is voltage (e.g., 0-10V), the pressure value = (current voltage / 10) × full-scale pressure. If it is a digital sensor, the pressure value output by the sensor is read directly.

[0055] S22: Determine the wheel position coordinates of the vehicle based on the pressure value received by the sensor and the position coordinates of the sensor.

[0056] In this embodiment, after determining the pressure value received by the sensor, the coordinates of the vehicle's wheel position are determined based on the sensor's pressure value and position coordinates.

[0057] In this embodiment, determining the coordinates of the vehicle's wheel position based on the pressure value received by each sensor and the sensor's position coordinates includes: S22-1: Determine the horizontal coordinate of the vehicle's wheel position based on the pressure value received by the sensor and the horizontal coordinate in the sensor's position coordinates.

[0058] In this embodiment, the abscissa of the vehicle's wheel position is first determined based on the pressure value received by the sensor and the abscissa in the sensor's position coordinates.

[0059] For example, assume the top left corner of the calibration area is the origin, X is to the right, and Y is downward. To pinpoint the exact location of the wheel, n pressure sensors are arranged at equal intervals. Assuming there are four sensors for positioning within a region close to the wheel, with coordinates (xa, ya), (xb, yb), (xc, yc), and (xd, yd) for each sensor, then the coordinates of the wheel center P1 are (Px, Py), where: Px=(Faxa+Fbxb+Fcxc+Fdxd) / (Fa+Fb+Fc+Fd) Wherein, Px is the abscissa of the wheel center, and its length L is in meters (m); Fa is the pressure value of sensor a in Newtons (N); Fb is the pressure value of sensor b in Newtons (N); Fc is the pressure value of sensor c in Newtons (N); Fd is the pressure value of sensor d in Newtons (N); xa is the abscissa of sensor a in meters (m); xb is the abscissa of sensor b in meters (m); xc is the abscissa of sensor c in meters (m); and xd is the abscissa of sensor d in meters (m). The meaning is that the "force × position" of each sensor constitutes the torque about the origin. The total torque divided by the total force yields the position of the center of mass.

[0060] S22-2: Determine the ordinate of the vehicle's wheel position based on the pressure value received by the sensor and the ordinate in the sensor's position coordinates.

[0061] In this embodiment, the ordinate of the vehicle's wheel position is determined based on the pressure value received by the sensor and the ordinate in the sensor's position coordinates.

[0062] For example, if the coordinates of each sensor are (xa, ya), (xb, yb), (xc, yc), and (xd, yd), then the coordinates of the wheel center P1 are (Px, Py). Py=(Faya+Fbyb+Fcyc+Fdyd) / (Fa+Fb+Fc+Fd) Wherein, Py is the x-coordinate of the wheel center, and its length L is in meters (m); Fa is the pressure value of sensor a in Newtons (N); Fb is the pressure value of sensor b in Newtons (N); Fc is the pressure value of sensor c in Newtons (N); Fd is the pressure value of sensor d in Newtons (N); ya is the y-coordinate of sensor a in meters (m); yb is the y-coordinate of sensor b in meters (m); yc is the y-coordinate of sensor c in meters (m); and yd is the y-coordinate of sensor d in meters (m).

[0063] S22-3: Use the coordinates of the center point of the wheel as the wheel position coordinates of the vehicle.

[0064] In this embodiment, after determining the horizontal and vertical coordinates of the center point of the wheel, the center point coordinates of the wheel are used as the wheel position coordinates.

[0065] refer to Figure 7 , Figure 7 This is a schematic diagram of wheel pressure according to an embodiment of this application, as shown below. Figure 7 As shown, there are four sensors around the tire. The coordinates of the wheel center point, i.e. the wheel position coordinates, are determined by the coordinates of these four sensors and the tire pressure on each sensor.

[0066] In this embodiment, the wheel position is detected by a pressure sensor, and the wheel position coordinates are determined, thereby realizing automatic wheel positioning, which is beneficial for accurate calibration of the vehicle camera.

[0067] In another embodiment of this application, determining the outline position of the vehicle based on the coordinates of the wheel positions includes: S31: Call the vehicle model data, which includes the front overhang distance, rear overhang distance, vehicle width, and vehicle length.

[0068] In this embodiment, the vehicle model data includes front overhang distance, rear overhang distance, vehicle width, and vehicle length. The front overhang distance is the distance from the center point of the front tire to the frontmost point of the vehicle, and the rear overhang distance is the distance from the rear tire to the rear end of the vehicle.

[0069] In this embodiment, when determining the outline position of the vehicle, the vehicle model data is first retrieved from the database.

[0070] For example, see reference Figure 8 , Figure 8 This is a schematic diagram of the vehicle outline according to an embodiment of this application, such as... Figure 8 As shown, the specific positions of the vehicle outline are determined based on the front overhang distance dFO, the rear overhang distance dRO, the vehicle width dW, and the vehicle length dL.

[0071] S32: Determine the outline size of the vehicle based on the vehicle model data.

[0072] In this embodiment, after obtaining the vehicle model data, the outline size of the vehicle is determined based on the vehicle model data. Determining the outline size of the vehicle is to ensure that the calibration pattern displayed on the display device is not obscured by the outline of the vehicle.

[0073] S33: Determine the outline position of the vehicle based on the position coordinates of the wheels and the outline size of the vehicle.

[0074] In this embodiment, the vehicle's outline position can be determined based on the wheel's position coordinates and the vehicle's outline. This allows for the determination of the vehicle's outline coverage area within the calibration space, as well as the determination of the vehicle's outline's center point.

[0075] In this embodiment, determining the position of the vehicle outline based on the wheel position is beneficial for accurately displaying the calibration pattern, thereby improving the calibration accuracy.

[0076] In another embodiment of this application, displaying a calibration pattern around the vehicle based on the contour position includes: S41: Obtain the location information of the vehicle's camera on the vehicle body and the pattern parameters of the calibration pattern from the database.

[0077] In this embodiment, the camera's position information on the vehicle body refers to the specific location where the camera is installed on the vehicle body. Cameras installed in different locations have different viewing angles. Pattern parameters include parameters such as the size and shape of the pattern.

[0078] In this embodiment, the position information of the vehicle's camera on the vehicle body is obtained from the data, and the pattern parameters of the calibration pattern are also obtained.

[0079] S42: Determine the display position of the calibration pattern based on the contour position, the position information, and the pattern parameters.

[0080] In this embodiment, after determining the vehicle's outline position, the camera's position on the vehicle body, and the pattern parameters, the display position of the calibration pattern is determined, i.e., the coordinates of the midpoint of the calibration pattern within the calibration space are determined. Based on the camera's position on the vehicle body, the camera's viewing angle can be determined, thereby determining the range that the camera can capture. Simultaneously, based on the outline position, it can be determined which parts of the ground the vehicle's outline obscures, thus avoiding the obscured parts. Based on the pattern parameters, the size of the pattern can be determined. Based on the above conditions, the display position of the pattern on the ground is determined to display a calibration pattern that is not obscured by the vehicle's outline and can be completely captured by the camera.

[0081] S43: The calibration pattern is displayed at the display position via a display device.

[0082] In this embodiment, after determining the display position of the calibration pattern, the corresponding coordinates are sent to the display device. After receiving the coordinates, the display device displays the calibration pattern at that display position.

[0083] For example, see reference Figure 9 , Figure 9 This is a schematic diagram of a calibration pattern display according to an embodiment of this application, as shown below. Figure 9 As shown, calibration patterns are displayed around the vehicle, allowing the camera to capture these calibration patterns completely.

[0084] In this embodiment, the display position of the calibration pattern is determined by the vehicle's outline position, the camera's position, and the parameters of the calibration pattern. This facilitates accurate acquisition of the calibration pattern and improves the accuracy of camera calibration.

[0085] In another embodiment of this application, determining the display position of the calibration pattern based on the contour position, the position information, and the pattern parameters includes: S51: Determine the shooting range of the camera based on the contour position and the position information.

[0086] In this embodiment, the camera's shooting range is first determined based on the vehicle's outline and the camera's position information.

[0087] For example, a fisheye surround-view camera is mounted on the top of a vehicle and can capture images of the surroundings. Based on the vehicle's outline and position, the area around that location is determined to be the camera's capture range.

[0088] S52: Determine the arrangement and size of the calibration pattern based on the pattern parameters.

[0089] In this embodiment, after obtaining the pattern parameters, the arrangement and size of the calibration pattern specified in the pattern parameters are determined.

[0090] S53: Based on the arrangement and size of the calibration pattern, select a coordinate point within the shooting range of the camera as the display position of the calibration pattern.

[0091] In this embodiment, after determining the arrangement and size of the calibration pattern, the coordinate points within the camera's shooting range are selected as the display positions of the calibration cluster, ensuring that the camera can completely capture the calibration pattern.

[0092] In another embodiment of this application, calibrating the vehicle's camera using the calibration pattern to obtain the camera's external parameters includes: S61: The calibration pattern is captured by the camera to obtain the captured image.

[0093] In this embodiment, when calibrating the camera, the camera is activated to acquire an image of the calibration pattern, thereby obtaining the acquired image.

[0094] S62: Perform corner detection on the acquired image to determine the coordinates of the first corner corresponding to the acquired image.

[0095] In this embodiment, corner points of an image refer to points in the image where the grayscale value changes drastically in both the horizontal and vertical directions. They typically appear at the intersection of two or more edges, such as the corners of buildings or the corners of a checkerboard pattern. These points possess direction invariance and local uniqueness, making them very important feature points in computer vision.

[0096] In this embodiment, corner detection is performed on the acquired image to determine the coordinates of the corner points in the acquired image, namely the coordinates of the first corner point.

[0097] For example, if there are 8 calibration patterns around the vehicle, each pattern consisting of multiple pixels, then 8 images are acquired, and the coordinates of the first corner point of these 8 images are identified.

[0098] S63: Obtain the coordinates of the second corner point of the calibration pattern in the vehicle coordinate system.

[0099] In this embodiment, the corner coordinates of the calibration pattern, i.e. the second corner coordinates, are determined in advance in the vehicle coordinate system. During calibration, the second corner coordinates of the calibration pattern in the vehicle coordinate system are directly obtained.

[0100] For example, for the eight images collected, the coordinates of the second corner point of these eight images in the vehicle coordinate system are obtained from the database.

[0101] S64: Match the first corner point coordinates with the second corner point coordinates to obtain the corresponding point pairs.

[0102] In this embodiment, the coordinates of the first corner point and the coordinates of the second corner point are matched to obtain corresponding point pairs. Each point pair contains one coordinate of the first corner point and one coordinate of the second corner point.

[0103] For example, the coordinates of the first and second corner points of eight calibration patterns are matched to obtain point pairs.

[0104] S65: Obtain the external parameters of the camera by using the coordinate difference between the point pairs.

[0105] In this embodiment, the external parameters of the camera are obtained by comparing the coordinate difference between two coordinates in a point pair.

[0106] For example, the external parameters of the camera, namely the rotation matrix R and the translation vector t, are derived from the coordinate difference of the point pair.

[0107] refer to Figure 10 , Figure 10 This is a schematic diagram of a camera calibration process according to an embodiment of this application, as shown below. Figure 10 As shown, after the vehicle enters the calibration room, the vehicle position is determined by the pressure sensor, and then the vehicle outline position is calculated by the calculation center, which in turn calculates the display position of the calibration pattern. After that, the display device displays the calibration pattern, and the camera is calibrated after the display is completed.

[0108] In the embodiments described above, automatic wheel positioning is achieved through a pressure sensing device, eliminating the need for manual intervention or alignment with wheel clamps. This significantly shortens preparation time before calibration and reduces human error. The display device dynamically adjusts the display position of the calibration pattern based on the vehicle profile and camera position, ensuring optimal matching between the calibration pattern and the vehicle and improving calibration accuracy. The system automatically adjusts the display position of the calibration pattern based on parameters such as the vehicle's front overhang distance, rear overhang distance, width, and length, adapting to the needs of different vehicle models. Even without strictly centered or perpendicular parking, the system can accurately calculate the vehicle profile and calibration pattern position, enhancing its adaptability and flexibility. The automatic completion of wheel positioning, vehicle profile calculation, and calibration pattern display through the pressure sensing device and calculation unit reduces the need for manual operation and lowers labor costs. The entire calibration process is highly automated, with simplified procedures, reduced operational complexity, and improved work efficiency. The pressure sensing device employs a high-sensitivity, high-precision sensor to ensure the accuracy of wheel position measurement and improve system reliability. The storage unit preserves various data generated during system operation, including wheel alignment information and calibration pattern parameters, ensuring data integrity and traceability and providing support for subsequent analysis and optimization. Through the collaborative work of the pressure sensing device, display device, computing unit, and storage unit, the entire process from wheel alignment to camera extrinsic parameter calculation is automated. This improves camera calibration efficiency and saves on the costs associated with camera calibration.

[0109] It should be noted that the camera calibration method provided in this application embodiment can be executed by a camera calibration device, or a control module in the camera calibration device for executing the loading camera calibration method. This application embodiment uses the execution of the loading camera calibration method by a camera calibration device as an example to illustrate the camera calibration method provided in this application embodiment.

[0110] refer to Figure 11 , Figure 11 This is a schematic diagram of a camera calibration device 1100 according to an embodiment of this application, as shown below. Figure 11 As shown, the device includes: The pressure signal receiving module 1101 is used to receive the pressure signal of the wheel through the pressure sensor when the vehicle is detected to have traveled to a preset position. The wheel position determination module 1102 is used to determine the coordinates of the wheel position of the vehicle based on the pressure signal. The contour position determination module 1103 is used to determine the contour position of the vehicle based on the coordinates of the wheel positions. The calibration pattern display module 1104 is used to display a calibration pattern around the vehicle according to the outline position; The camera calibration module 1105 is used to calibrate the camera of the vehicle using the calibration pattern to obtain the external parameters of the camera.

[0111] Optionally, the wheel position determination module includes: The pressure value determination submodule is used to determine the pressure value received by the sensor based on the pressure signal; The wheel coordinate determination submodule is used to determine the coordinates of the vehicle's wheel position based on the pressure value received by the sensor and the sensor's position coordinates.

[0112] Optionally, the wheel coordinate determination submodule includes: The first coordinate determination submodule is used to determine the abscissa of the vehicle's wheel position based on the pressure value received by the sensor and the abscissa in the sensor's position coordinates. The second coordinate determination submodule is used to determine the ordinate of the vehicle's wheel position based on the pressure value received by the sensor and the ordinate in the sensor's position coordinates. The third coordinate determination submodule is used to use the coordinates of the center point of the wheel as the wheel position coordinates of the vehicle.

[0113] Optionally, the contour position determination module includes: The vehicle model data retrieval submodule is used to retrieve the vehicle model data, which includes the front overhang distance, rear overhang distance, vehicle width, and vehicle length. The outline size determination submodule is used to determine the outline size of the vehicle based on the vehicle model data; The contour position determination submodule is used to determine the contour position of the vehicle based on the position coordinates of the wheels and the contour size of the vehicle.

[0114] Optionally, the calibration pattern display module includes: The pattern parameter determination submodule is used to obtain the position information of the vehicle's camera on the vehicle body and the pattern parameters of the calibration pattern from the database; The display position determination submodule is used to determine the display position of the calibration pattern based on the outline position, the position information, and the pattern parameters. The calibration pattern display submodule is used to display the calibration pattern at the display position via a display device.

[0115] Optionally, the display position determination submodule includes: The shooting range determination submodule is used to determine the shooting range of the camera based on the contour position and the position information; The layout size determination submodule is used to determine the layout and size of the calibration pattern based on the pattern parameters; The display position acquisition submodule is used to select coordinate points within the shooting range of the camera as the display position of the calibration pattern based on the arrangement and size of the calibration pattern.

[0116] Optionally, the camera calibration module includes: The image acquisition submodule is used to acquire an image of the calibration pattern through the camera to obtain the acquired image; The corner detection submodule is used to perform corner detection on the acquired image and determine the coordinates of the first corner corresponding to the acquired image; The corner point acquisition submodule is used to acquire the coordinates of the second corner point of the calibration pattern in the vehicle coordinate system. The corner matching submodule is used to perform point-to-point matching using the coordinates of the first corner point and the coordinates of the second corner point to obtain the corresponding point pairs; The external parameter determination submodule is used to obtain the external parameters of the camera by the coordinate difference of the point pair.

[0117] The camera calibration device in this application embodiment can be a device, or a component, integrated circuit, or chip in a terminal. The device can be a mobile electronic device or a non-mobile electronic device. For example, mobile electronic devices can be mobile phones, tablets, laptops, PDAs, in-vehicle electronic devices, wearable devices, ultra-mobile personal computers (UMPCs), netbooks, or personal digital assistants (PDAs), etc., while non-mobile electronic devices can be servers, network attached storage (NAS), personal computers (PCs), televisions (TVs), ATMs, or self-service machines, etc. This application embodiment does not impose specific limitations.

[0118] The camera calibration device in this application embodiment can be a device with an operating system. This operating system can be Android, iOS, or other possible operating systems; this application embodiment does not specifically limit it.

[0119] The camera calibration device provided in this application embodiment can achieve... Figures 1 to 10 The various processes implemented by the camera calibration device in the method embodiment will not be described again here to avoid repetition.

[0120] Optionally, this application embodiment also provides an electronic device, including a processor 110, a memory 109, and a program or instructions stored in the memory 109 and executable on the processor 110. When the program or instructions are executed by the processor 110, they implement the various processes of the above-described camera calibration method embodiment and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0121] It should be noted that the electronic devices in the embodiments of this application include the mobile electronic devices and non-mobile electronic devices described above.

[0122] Figure 12 This is a schematic diagram of the hardware structure of an electronic device proposed in an embodiment of this application. The electronic device 100 includes, but is not limited to, components such as: radio frequency unit 101, network module 102, audio output unit 103, input unit 104, sensor 105, display unit 106, user input unit 107, interface unit 108, memory 109, and processor 110.

[0123] Those skilled in the art will understand that the electronic device 100 may also include a power supply (such as a battery) for supplying power to various components. The power supply may be logically connected to the processor 110 through a power management system, thereby enabling functions such as managing charging, discharging, and power consumption through the power management system. Figure 12 The electronic device structure shown does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown, or combine certain components, or have different component arrangements, which will not be elaborated here. This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described camera calibration method embodiments and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0124] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0125] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described camera calibration method embodiments and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0126] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0127] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0129] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A camera calibration method, characterized in that, The method is applied to the computing unit of a camera calibration system, including: When the vehicle is detected to have moved to a preset position, the pressure signal of the wheel is received by the pressure sensor; Based on the pressure signal, determine the coordinates of the vehicle's wheel position; The outline position of the vehicle is determined based on the coordinates of the wheel positions; Based on the outline position, a calibration pattern is displayed around the vehicle; The vehicle's camera is calibrated using the calibration pattern to obtain the camera's external parameters.

2. The camera calibration method according to claim 1, characterized in that, Determining the wheel position information of the vehicle based on the pressure signal includes: The pressure value applied to the sensor is determined based on the pressure signal. The coordinates of the vehicle's wheel position are determined based on the pressure value received by the sensor and the sensor's position coordinates.

3. The camera calibration method according to claim 2, characterized in that, Determining the wheel coordinates of the vehicle based on the pressure value received by each sensor and the sensor's position coordinates includes: The horizontal coordinate of the vehicle's wheel position is determined based on the pressure value received by the sensor and the horizontal coordinate of the sensor's position coordinates. The ordinate of the vehicle's wheel position is determined based on the pressure value received by the sensor and the ordinate of the sensor's position coordinates. The coordinates of the center point of the wheel are used as the wheel position coordinates of the vehicle.

4. The camera positioning method according to claim 1, characterized in that, Determining the vehicle's outline position based on the coordinates of the wheel positions includes: The vehicle model data is retrieved, including the front overhang distance, rear overhang distance, vehicle width, and vehicle length. Based on the vehicle model data, determine the outline size of the vehicle; The outline position of the vehicle is determined based on the position coordinates of the wheels and the outline size of the vehicle.

5. The camera positioning method according to claim 1, characterized in that, The step of displaying a calibration pattern around the vehicle based on the outline position includes: Obtain the location information of the vehicle's camera on the vehicle body and the pattern parameters of the calibration pattern from the database; The display position of the calibration pattern is determined based on the outline position, the position information, and the pattern parameters. The calibration pattern is displayed at the display position via a display device.

6. The camera calibration method according to claim 5, characterized in that, Determining the display position of the calibration pattern based on the contour position, the position information, and the pattern parameters includes: The shooting range of the camera is determined based on the outline position and the position information; Based on the pattern parameters, determine the arrangement and size of the calibration pattern; Based on the arrangement and size of the calibration pattern, select a coordinate point within the camera's shooting range as the display position of the calibration pattern.

7. The camera calibration method according to claim 1, characterized in that, The step of calibrating the vehicle's camera using the calibration pattern to obtain the camera's external parameters includes: The calibration pattern is captured by the camera to obtain the captured image; Corner detection is performed on the acquired image to determine the coordinates of the first corner point corresponding to the acquired image; Obtain the coordinates of the second corner point of the calibration pattern in the vehicle coordinate system; By matching the coordinates of the first corner point with the coordinates of the second corner point, the corresponding point pairs are obtained; The external parameters of the camera are obtained by using the coordinate difference between the point pairs.

8. A camera calibration system, characterized in that, The system includes: A pressure sensor is used to obtain the pressure value of the wheel on the ground and is installed on the ground in the calibration room. A display device for displaying calibration patterns is installed on the floor of the calibration room. A transparent protective device is installed above the display device; A computing unit for performing the steps in any of the methods described in claims 1-7.

9. A camera calibration device, characterized in that, The device includes: The pressure signal receiving module is used to receive the pressure signal of the wheels through the pressure sensor when the vehicle is detected to have traveled to a preset position. A wheel position determination module is used to determine the coordinates of the vehicle's wheel position based on the pressure signal. The contour position determination module is used to determine the contour position of the vehicle based on the coordinates of the wheel positions. A calibration pattern display module is used to display a calibration pattern around the vehicle according to the outline position; The camera calibration module is used to calibrate the vehicle's camera using the calibration pattern to obtain the camera's external parameters.

10. An electronic device, characterized in that, It includes a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of any of the methods described in claims 1-7.

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