Device, system and method for determining the position of a calibration tool in front of a motor vehicle

Abstract

The invention relates to a mobile device (12) for determining the position of a calibration tool (10) in front of a motor vehicle (2), in particular for preparing a calibration of a vehicle sensor (8) integrated into the motor vehicle (2), comprising: a tripod (14); a measurement panel (18); and at least one camera (20). The measurement panel (18) and the at least one camera (20) are attached to the tripod (14) with a specified fixed spatial relationship to one another.

Description

[0001] Description

[0002] title

[0003] Device, system and method for determining the position of a calibration tool in front of a motor vehicle

[0004] The present invention relates to a device, a system and a method for determining the position of a calibration tool in front of a motor vehicle, in particular for preparing a calibration of a vehicle sensor installed in the motor vehicle.

[0005] State of the art

[0006] Modern motor vehicles often feature a range of vehicle sensors that assist the driver in perceiving their surroundings. For example, the use of cameras, a radar system, a LIDAR system, distance sensors, or similar devices associated with a driver assistance system is common. It is common practice for vehicle sensors with a more or less directional detection range to be calibrated to ensure correct function. Calibration can be performed during final assembly or shortly before delivery of the vehicle. Recalibration of the vehicle sensors may be necessary after a repair or maintenance of the vehicle.

[0007] To calibrate a vehicle sensor, a calibration tool is positioned as a reference object in the field of view of the respective vehicle sensor in front of the vehicle.

[0008] The calibration process requires the reference object to be positioned very precisely to achieve a repeatable, accurate result. Since the vehicles are moved on their own wheels before calibration and are therefore never in exactly the same position, the precise placement of the reference objects must be repeated for each vehicle, which is time-consuming and costly.

[0009] It is therefore an object of the invention to simplify the calibration of vehicle sensors installed in motor vehicles.

[0010] Disclosure of the invention

[0011] The invention comprises a mobile device for determining the position of a calibration tool in front of a motor vehicle, in particular for preparing a calibration of a vehicle sensor installed in the motor vehicle. A mobile device according to the invention comprises: a tripod; a measuring panel; and at least one camera. The measuring panel and the at least one camera are mounted on the tripod in a predetermined, fixed spatial relationship to one another.

[0012] The invention also encompasses a system for determining the position of a calibration tool in front of a vehicle sensor, in particular for preparing a calibration of a vehicle sensor installed in a motor vehicle. The system comprises: at least two mobile devices according to the invention; at least one mobile calibration tool that can be optically detected by a vehicle sensor; and an evaluation device configured to evaluate images provided by the cameras of the at least two mobile devices in order to determine the position of the calibration tool relative to the vehicle sensor.

[0013] A system according to the invention for determining the position of a calibration tool in front of a vehicle sensor can in particular comprise two, three or four mobile devices.

[0014] The invention further comprises a method for determining the position of a calibration tool in front of a vehicle sensor, in particular for preparing the vehicle sensor. A method according to the invention comprises: placing a vehicle with the vehicle sensor on a measuring station; placing at least two mobile devices according to the invention on the measuring station; and placing a calibration tool on the measuring station within the field of view of the vehicle sensor.The method further comprises taking images of the measuring station with the cameras of the at least two mobile devices; identifying the measuring panel attached to the at least one other mobile device in the taken images and defining a coordinate system predetermined by the mobile devices; identifying the motor vehicle in the taken images and determining the position of the motor vehicle, in particular of the vehicle sensor, in the coordinate system defined by the devices; identifying the at least one calibration tool in the taken images and determining the position of the at least one calibration tool in the coordinate system defined by the devices; and determining the position of the at least one calibration tool in a local coordinate system of the vehicle sensor.

[0015] The invention also encompasses a method for calibrating a vehicle sensor, in particular a vehicle sensor of a driver assistance system, wherein the method comprises determining the position of at least one calibration tool in front of the vehicle sensor to be calibrated using the method described above; detecting the at least one calibration tool with the vehicle sensor to be calibrated, and calibrating the vehicle sensor based on the previously determined position of the at least one calibration tool in front of the vehicle sensor.

[0016] With a system according to the invention, which comprises mobile devices according to the invention, and with a method according to the invention, the position and orientation of a calibration tool, which serves as a reference object for calibrating a vehicle sensor, in front of a vehicle sensor to be calibrated can be determined easily and with high accuracy.

[0017] It is therefore not necessary to position the calibration tool with high precision at a fixed position in front of the vehicle or in front of the vehicle sensor to be calibrated.

[0018] The calibration of vehicle sensors can therefore be simplified, particularly in the workshop, and costs can be reduced. In one embodiment, a mobile device according to the invention comprises a component carrier that is attached to the tripod. In this embodiment, the measuring panel and the at least one camera are attached to the component carrier in a predetermined, fixed spatial relationship to one another. With the aid of such a component carrier, which can in particular be designed to be particularly mechanically stable, the spatial relationship between the measuring panel and the at least one camera can be determined particularly reliably and permanently.

[0019] In one embodiment, a two-dimensional pattern, for example a checkerboard pattern, is formed on the measuring panel of the mobile device.

[0020] In one embodiment, a three-dimensional pattern is formed on the measuring panel of the mobile device.

[0021] With measuring boards on which such patterns are formed, the position and orientation of the mobile device with respect to a camera, in particular with respect to a camera attached to another mobile device, can be reliably determined.

[0022] The measuring panel of each mobile device may have a different pattern so that the mobile devices can be distinguished and clearly identified by the measuring panels with different patterns.

[0023] In one embodiment, the at least one camera is a wide-angle camera, in particular a so-called "fisheye" camera, in order to make it possible to optically capture the entire measuring station with the motor vehicle, the calibration tool and other mobile devices.

[0024] In one embodiment, the camera is a 2D camera. A 2D camera is particularly cost-effective.

[0025] In one embodiment, the camera is a 3D camera. A 3D camera provides images containing three-dimensional information. In one embodiment, the camera is a high frame rate camera. A camera with a high frame rate is advantageous if the calibration tool or parts of the calibration tool are moved during image acquisition.

[0026] In one embodiment, the mobile device is additionally equipped with a LIDAR sensor arranged in a fixed spatial relationship to the measuring panel and the at least one camera. The LIDAR sensor can, in particular, be mounted in a fixed spatial relationship to the component carrier.

[0027] With the help of LIDAR sensors, the accuracy of the measurement results can be further improved, especially at greater distances between the vehicle and the mobile devices.

[0028] In one embodiment, a system according to the invention comprises at least one vehicle measuring panel designed for mounting on a vehicle. Vehicle measuring panels attached to the vehicle, in particular to the vehicle's wheels, can further improve the accuracy of the position of the motor vehicle determined from the captured images and thus also the accuracy of the determined position of the calibration tool in front of the vehicle.

[0029] In one embodiment, a method according to the invention for calibrating a vehicle sensor comprises moving the at least one calibration tool with respect to the vehicle sensor to be calibrated during calibration.

[0030] The at least one calibration tool can be moved to different predetermined positions in an automated process and / or arranged in different orientations in front of the vehicle sensor to be calibrated.

[0031] The method may in particular comprise moving the at least one calibration tool in a pivoting movement around the vehicle sensor to be calibrated during calibration.

[0032] Alternatively or additionally, the at least one calibration tool can be moved in a linear motion relative to the vehicle sensor. In one embodiment, a method according to the invention for calibrating a vehicle sensor comprises permanently or temporarily arranging the at least one calibration tool above the hood of the motor vehicle during calibration.

[0033] An embodiment of the invention is described below with reference to the accompanying figures.

[0034] Short the

[0035] Figure 1 shows a schematic representation of a measuring station with a motor vehicle, a calibration tool and a system according to the invention for determining the position of the calibration tool in front of the motor vehicle;

[0036] Figure 2 shows a mobile device according to the invention for determining a position of the calibration tool in front of a motor vehicle; and

[0037] Figure 3 is a flowchart of a method for determining the position of a calibration tool in front of a motor vehicle according to an embodiment of the invention.

[0038] Figure 1 shows a schematic plan view of a measuring station with a motor vehicle 2 equipped with at least one vehicle sensor 8. The vehicle sensor 8 can, in particular, be a sensor of a driver assistance system 9. The vehicle sensor 8 can, for example, be an optical sensor, in particular a camera, a radar sensor, or a laser sensor (LIDAR).

[0039] The motor vehicle 2 has four wheels 4, each of which has a vehicle measuring panel 6 attached to it.

[0040] Although Figure 1 shows a motor vehicle 2 with four wheels 4, the invention can also be used in conjunction with motor vehicles 2 that have two, three, or more than four wheels 4. A calibration tool 10 is arranged in front of the motor vehicle 2, in particular in front of the vehicle sensor 8, which makes it possible to calibrate the vehicle sensor 8. In order to calibrate the vehicle sensor 8 using the calibration tool 10, it is necessary to know the position and orientation of the calibration tool 10 with respect to the motor vehicle 2, in particular with respect to the vehicle sensor 8, with sufficient accuracy.

[0041] In order to determine the position and orientation of the calibration tool 10 with respect to the motor vehicle 2, in particular with respect to the vehicle sensor 8, the calibration tool 10 is equipped with a calibration tool measuring board 11. The calibration tool measuring board 11 has a calibration tool measuring board pattern, for example, a checkerboard pattern.

[0042] In addition, four mobile devices 12 are arranged on the measuring station, which make it possible to determine the position and orientation of the calibration tool 10 with respect to the motor vehicle 2, in particular with respect to the vehicle sensor 8.

[0043] A system according to the invention for determining the position of the calibration tool 10 in front of the motor vehicle 2 comprises, in addition to the mobile devices 12, also an evaluation device 24 which is designed to evaluate images provided by the mobile devices 12 in order to determine the position and orientation of the calibration tool 10 with respect to the motor vehicle 2.

[0044] The evaluation device 24 can be designed as part of one of the mobile devices 12 or spatially separated from the mobile devices 12.

[0045] Although four mobile devices 12 are present in the embodiment shown in Figure 1, a system according to the invention for determining the position and orientation of the calibration tool 10 may also comprise fewer than four mobile devices 12, for example two or three mobile devices 12.

[0046] Figure 2 shows a three-dimensional representation of an embodiment of a mobile device 12 according to the invention. The mobile device 12 comprises a stand 14, in particular a tripod, which supports the mobile device 12 on the floor of the measuring station.

[0047] A component carrier 16 is attached to the stand 14. The component carrier 16 can, in particular, be mounted on the stand 14 in a height-adjustable manner.

[0048] A measuring panel 18 and a camera 20 are attached to the component carrier 16. Optionally, a laser sensor (LIDAR sensor) 22 can also be attached to the component carrier 16.

[0049] The measuring panel 18, the camera 20 and the laser sensor 22 (if present) are mounted on the component carrier 16 in a predetermined fixed spatial relationship to one another, in particular at fixed angles and distances from one another, so that their positions and orientations to one another are fixed.

[0050] A characteristic pattern, such as a checkerboard pattern, is formed on the measuring plate 18, which is attached to the component carrier 16. The pattern can be a two-dimensional pattern or a three-dimensional pattern.

[0051] The measuring panel 18 of each mobile device 12 may have a different pattern so that the mobile devices 12 can be distinguished and uniquely identified by means of the measuring panels 18 with different patterns.

[0052] Figure 2 shows a three-dimensional pattern. The 3D effect of the three-dimensional pattern is greatly exaggerated so that it is clearly visible in Figure 2.

[0053] With reference to Figure 3, a method 100 according to an embodiment of the invention for determining the position and orientation of the calibration tool 10 with respect to the motor vehicle 2 is described below.

[0054] In a first step 110, the motor vehicle 2 is connected to the vehicle sensor

[0055] 8, the calibration tool 10 and the mobile devices 12 are placed on the measuring station. The motor vehicle 2, the calibration tool 10 and the mobile devices 12 can be placed on the measuring station in any chronological order.

[0056] In an optional second step 120, vehicle measuring panels 6 can be attached to the wheels 4 of the motor vehicle 2, as shown in Figure 1.

[0057] In a subsequent step 130, the camera 20 of each of the mobile devices 12 arranged at the measuring station optically captures a measuring panel 18 of at least one other mobile device 12 arranged at the measuring station. Each camera 20 records at least one image of the optically captured measuring panel(s) 18.

[0058] The images recorded by the cameras 20 also each contain at least one area of ​​the motor vehicle 2. At least one image recorded by the camera 20 of at least one of the mobile devices 12 also contains the calibration tool 10, in particular the calibration tool measuring board 11 of the calibration tool 10.

[0059] The images captured by the cameras 20 are transmitted to the evaluation device 24.

[0060] The images captured by the cameras 20 can be transmitted to the evaluation device 24 either wired or wirelessly, e.g., via a WLAN or Bluetooth connection. For this purpose, the cameras 20 and the evaluation device 24 can be equipped with suitable transmitters and receivers, which are not explicitly shown in Figures 1 and 2.

[0061] In step 140, the evaluation device 24 evaluates the images captured by the cameras 20 and determines a global coordinate system G defined by the mobile devices 12.

[0062] The images recorded by the cameras 20 of the mobile devices 12 and transmitted to the evaluation device 24 also contain partial areas of the motor vehicle 2. If two vehicle measuring panels 6 are mounted on the wheels 4 of the motor vehicle, as shown in Figure 1, the recorded images also contain, in particular, images of the vehicle measuring panels 6 attached to the wheels 4 of the motor vehicle 2.

[0063] In the next step 150, the evaluation device 24 evaluates the images recorded by the cameras 20 in order to determine the position and spatial orientation of the motor vehicle 2 on the measuring station in the global coordinate system G defined by the mobile devices 12.

[0064] This may in particular include evaluating the images of the vehicle measuring panels 6 attached to the wheels 4 of the motor vehicle 2.

[0065] Alternatively or additionally, characteristic features of the body of the motor vehicle 2 can be identified in the images captured by the cameras 20, e.g., with the aid of artificial intelligence. The position and orientation of the motor vehicle 2 in the global coordinate system G can then be determined based on these characteristic features of the body of the motor vehicle 2.

[0066] The position and orientation of the vehicle sensor 8 to be calibrated in the local coordinate system L of the motor vehicle 2 is known. This information is provided, for example, by the manufacturer of the motor vehicle 2 and / or the vehicle sensor 8.

[0067] In step 160, the position and orientation of the vehicle sensor 8 to be calibrated in the local coordinate system L of the motor vehicle 2 are taken from a database or manually entered into the evaluation device 24.

[0068] After the position and orientation of the motor vehicle 2 in the global coordinate system G have been determined, the position and orientation of the vehicle sensor 8 to be calibrated can also be transformed from the local coordinate system L of the motor vehicle 2 into the global coordinate system G in step 170.

[0069] The images recorded by the camera 20 of at least one of the mobile devices 12 also contain images of the calibration tool 10, in particular images of the calibration tool measuring board 11 of the calibration tool 10. In a step 180, the position and orientation of the calibration tool 10 in the global coordinate system G are determined by evaluating these images.

[0070] After both the position and orientation of the vehicle sensor 8 to be calibrated and the position and orientation of the calibration tool 10 in the global coordinate system G are known in this way, the position and orientation of the calibration tool 10 in a local coordinate system S of the vehicle sensor 8 can be determined in a subsequent step 190.

[0071] With this information, the vehicle sensor 8 can be calibrated reliably and with high accuracy.

[0072] Optionally, a method according to the invention for calibrating a vehicle sensor 8 can comprise moving the at least one calibration tool 10 relative to the vehicle sensor 8 during the calibration process. The method can in particular comprise moving the at least one calibration tool 10 in a pivoting movement around the vehicle sensor 8. Alternatively or additionally, the at least one calibration tool 10 can be moved in a linear movement relative to the vehicle sensor 8.

[0073] The at least one calibration tool 10 can be moved to various predetermined positions and / or arranged in different orientations in front of the vehicle sensor 8 to be calibrated in an automated process.

[0074] A method according to the invention for calibrating a vehicle sensor 8 can also comprise arranging the at least one calibration tool 10 permanently or temporarily above the hood of the motor vehicle 2.

[0075] With the aid of LIDAR sensors 22, which can optionally be provided on the mobile devices 12, the accuracy of the measurement results can be further improved, particularly at greater distances between the motor vehicle 2 and the mobile devices 12, so that the position and orientation of the calibration tool 10 in the local coordinate system S of the vehicle sensor 8 can be determined even more precisely.

Claims

1 . A mobile device (12) for determining the position of a calibration tool (10) in front of a motor vehicle (2), in particular for preparing a calibration of a vehicle sensor (8) installed in the motor vehicle (2), wherein the mobile device (12) comprises: a tripod (14); a measuring panel (18) and at least one camera (20), and wherein the measuring panel (18) and the at least one camera (20) are attached to the tripod (14) in a predetermined, fixed spatial relationship to one another.

2. Mobile device (12) according to claim 1, comprising a component carrier (16) mounted on the tripod (14), wherein the measuring panel (18) and the at least one camera (20) are mounted on the component carrier (16) in a predetermined fixed spatial relationship to one another.

3. Mobile device (12) according to claim 1 or 2, wherein a two-dimensional pattern or a three-dimensional pattern is formed on the measuring panel (18).

4. Mobile device (12) according to one of the preceding claims, wherein the camera (20) is a wide-angle camera, and / or wherein the camera (20) is a 2D camera (20) or a 3D camera (20).

5. Mobile device (12) according to one of the preceding claims, wherein the mobile device (12) additionally comprises a LIDAR sensor (22) arranged in a fixed spatial relationship to the measuring panel (18) and the at least one camera (20) on the tripod (14); wherein the LIDAR sensor (22) is in particular attached to the component carrier (16).

6. A system (10, 12, 24) for determining the position of a calibration tool (10) in front of a vehicle sensor (8), in particular for preparing a calibration of a vehicle sensor (8) installed in a motor vehicle (2), wherein the system (10, 12, 24) comprises: at least two mobile devices (12) according to one of the preceding claims; at least one calibration tool (10) that can be optically detected by a vehicle sensor (8); and an evaluation device (24) that is designed to evaluate images provided by the cameras (20) of the at least two mobile devices (12) in order to determine the position of the calibration tool (10) with respect to the vehicle sensor (8).

7. System (10, 12, 24) for determining the position of a calibration tool (10) in front of a vehicle sensor (8) according to claim 6, wherein the system (10, 12, 24) comprises two, three or four mobile devices (12).

8. System (10, 12, 24) for determining the position of a calibration tool (10) in front of a motor vehicle (2) according to claim 6 or 7, wherein the patterns formed on the measuring panels (18) of different mobile devices (12) differ from one another.

9. System (10, 12, 24) for determining the position of a calibration tool (10) in front of a motor vehicle (2) according to one of claims 6 to 8, wherein the system (10, 12, 24) comprises at least one vehicle measuring panel (6) which is designed to be mounted on a vehicle (2).

10. A method for determining the position of a calibration tool (10) in front of a vehicle sensor (8), in particular for preparing a calibration of the vehicle sensor (8), the method comprising: placing a vehicle (2) with the vehicle sensor (8) on a measuring station; placing at least two mobile devices (12) according to one of claims 1 to 5 on the measuring station; placing a calibration tool (10) in the field of view of the vehicle sensor (8) on the measuring station; recording images with the cameras (20) of the at least two mobile devices (12); identifying the measuring panel (18) attached to the at least one other mobile device (12) in the recorded images and defining a coordinate system (G) predetermined by the mobile devices (12);to identify the motor vehicle (2) in the recorded images and to determine the position of the motor vehicle (2), in particular of the vehicle sensor (8), in the coordinate system (G) defined by the mobile devices (12); to identify the at least one calibration tool (10) in the recorded images and to determine the position of the at least one calibration tool (10) in the coordinate system (G) defined by the mobile devices (12); and to determine the position of the at least one calibration tool (10) in a local coordinate system (S) of the vehicle sensor (8); 11. A method for calibrating a vehicle sensor (8), in particular a vehicle sensor (8) of a driver assistance system (9), the method comprising: determining the position of at least one calibration tool (10) in front of the vehicle sensor (8) to be calibrated using a method according to claim 10; detecting the at least one calibration tool (10) with the vehicle sensor (8) to be calibrated and calibrating the vehicle sensor (8) on the basis of the previously determined position of the at least one calibration tool (10) in front of the vehicle sensor (8).

12. A method for calibrating a vehicle sensor (8) according to claim 11, wherein the method comprises moving the at least one calibration tool (10) with respect to the vehicle sensor (8) during calibration; wherein the method in particular comprises moving the at least one calibration tool (10) in a pivoting movement around the vehicle sensor (8) during calibration.

13. A method for calibrating a vehicle sensor (8) according to claim 11 or 12, wherein the method comprises arranging the at least one calibration tool (10) above the hood of the motor vehicle (2).

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