Method and device for positioning calibration device in front of motor vehicle

Abstract

The invention relates to a method for positioning a calibration device (20) in front of a motor vehicle (4), said calibration device being provided for calibrating a driver assistance system (16), comprising: driving at least one image recording device (6a, 6b) with the motor vehicle (4); optically detecting a characteristic feature of the motor vehicle (4) by means of the at least one image recording device (6a, 6b) during the movement of the motor vehicle (4) and providing 3D information about the optically detected characteristic feature of the motor vehicle; determining the longitudinal axis of travel (FA) of the motor vehicle (4) and the distance (A) between the front end (F) and the rear axle of the motor vehicle (4) by evaluating the provided 3D information; parking the motor vehicle (4) in front of the at least one image recording device (6a, 6b); determining the position of the stopped motor vehicle (4) in front of the at least one image recording device (6a, 6b); and determining the required position of the calibration device (20) in front of the motor vehicle (4) for calibrating the driver assistance system (16) on the basis of the previously determined parameter.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for positioning a calibration device in front of a motor vehicle, wherein the calibration device is used to calibrate a driver assistance system. Background Technology

[0002] To calibrate sensors of driver assistance systems, such as those typically installed in motor vehicles, especially in workshop areas, a calibration device with one or more measuring plates (“calibration plates”) is usually used. At least one optical pattern can be formed on each calibration plate, which can be optically detected by at least one optical sensor of the driver assistance system to be calibrated, in order to calibrate the driver assistance system or at least one sensor of the driver assistance system.

[0003] For calibration to be performed properly, the calibration device must be positioned in front of the vehicle at a location pre-specified by the driver assistance system manufacturer. This requires determining the vehicle's longitudinal axis and the distance between the calibration device and the vehicle. This necessitates manual operations, such as mounting the measuring plate ("calibration plate") to the vehicle's wheels and / or manually determining the distance between the calibration device and the vehicle. These manual operations are complex, time-consuming, and prone to error.

[0004] Therefore, the object of the present invention is to improve and simplify the positioning of a calibration device in front of a motor vehicle, wherein the calibration device is configured to calibrate sensors of a driver assistance system. Summary of the Invention

[0005] The method according to the present invention for positioning a calibration device for calibrating sensors used to calibrate driver assistance systems in front of a motor vehicle includes: A motor vehicle equipped with a driver assistance system featuring at least one sensor is driven towards an image recording device. During the vehicle's movement, the image recording device optically detects characteristic features of the vehicle and provides 3D information about these optically detected features. The vehicle's longitudinal axis of travel is determined by evaluating the provided 3D information. The distance between the front and rear axles of the vehicle is determined by evaluating the provided 3D information. The vehicle is then stopped in front of the image recording device. The position of the stopped vehicle in front of the image recording device is determined. Based on previously determined parameters, the position of a calibration device in front of the vehicle required for calibrating the driver assistance system is determined. These parameters include, in particular, the vehicle's longitudinal axis of travel, the distance between the front and rear axles of the vehicle, and the position of the vehicle in front of the image recording device.

[0006] The provided 3D information can be evaluated during and / or after the vehicle has come to a stop to determine the vehicle's longitudinal axis of travel and the distance between the front and rear axles.

[0007] The invention also includes a positioning device for positioning a calibration device in front of a motor vehicle, the calibration device being configured to calibrate a driver assistance system. The positioning device includes an image recording device and an evaluation device. The image recording device is designed to optically detect characteristic features of the motor vehicle and provide 3D information about the optically detected characteristic features of the motor vehicle. The evaluation device is designed to evaluate the 3D information provided by the image recording device to determine the required position of the calibration device in front of the motor vehicle for calibrating the driver assistance system. The positioning device may further include a display device configured to display the position of the calibration device determined by the evaluation device.

[0008] The positioning device according to the invention is specifically designed to, during the process of a motor vehicle moving toward an image recording device, optically detect the characteristics of the motor vehicle and provide 3D information about the optically detected characteristics of the motor vehicle; determine the longitudinal axis of the motor vehicle by evaluating the provided 3D information; determine the distance between the front and rear axles of the motor vehicle; and determine the position of the motor vehicle in front of the image recording device after the motor vehicle has stopped moving.

[0009] The provided 3D information can be evaluated during and / or after the vehicle has come to a stop to determine the vehicle's longitudinal axis of travel and the distance between the front and rear axles.

[0010] The positioning device and method according to the invention simplify the positioning of a calibration device, which is used to calibrate sensors for driver assistance systems, in front of a motor vehicle. Specifically, the positioning device and method according to the invention enable the determination of the calibration device's position in front of a motor vehicle without the need to install a measuring plate ("target") on the vehicle. Furthermore, the positioning accuracy of the calibration device in front of the motor vehicle can be improved, and the risk of mispositioning of the calibration device in front of the motor vehicle can be minimized.

[0011] In one embodiment, optical detection of the characteristic features of a motor vehicle includes recording images of the motor vehicle, particularly three-dimensional images, and identifying the characteristic features in the recorded images. In this way, the characteristic features of a motor vehicle can be reliably and cost-effectively identified.

[0012] In one embodiment, the method includes: tracking the motion of characteristic features in a recorded image as the vehicle moves toward the image recording device. This enables the determination of the vehicle's longitudinal axis of travel based on information about the characteristic features contained in the recorded image.

[0013] In one embodiment, the method includes creating a depth map of the motor vehicle after it has stopped in front of an image recording device. The depth map contains information about the distance between characteristic features of the motor vehicle and the image recording device. With such a depth map, information about the three-dimensional geometry of the motor vehicle provided by at least one image recording device can be evaluated particularly efficiently. In particular, the depth map can be used to identify three-dimensional objects, especially motor vehicles, and to determine the symmetry of the object.

[0014] In one embodiment, the method includes displaying on a display device a previously calculated location where the calibration device should be positioned. Displaying the previously calculated location allows a person to read the calculated location from the display device and, based on the read information, position the calibration device at the calculated location in front of the motor vehicle.

[0015] In one embodiment, the method further includes positioning the calibration device at a calculated location in front of the vehicle. This positioning can be performed manually or automatically. In particular, the calibration device can be designed to be independently positioned in front of the vehicle at a location determined by the positioning device.

[0016] In one embodiment of the positioning device according to the invention, the image recording device is mounted on the calibration device. In this case, the image recording device and the calibration device can be moved together through the measuring station. This makes the positioning configuration of the calibration device in front of the vehicle particularly compact and space-saving.

[0017] In one embodiment, the at least one image recording device is arranged and aligned such that the calibration device is located within the field of view of the at least one image recording device. In this way, the current position of the calibration device on the measuring station can be determined and monitored based on the images recorded by the at least one image recording device.

[0018] In one embodiment, the at least one image recording device includes a first image recording device and a second image recording device. The first image recording device may be arranged in front of the motor vehicle and is designed to record an image containing a front view of the motor vehicle. The second image recording device may be arranged to the side of the motor vehicle and is designed to record a side view of the motor vehicle, particularly an image containing the rear axle of the motor vehicle.

[0019] In another embodiment, another image recording device, particularly a third image recording device, may be arranged on the other side of the vehicle (opposite to the second image recording device) to record images from the other side of the vehicle. In this way, the accuracy of the parameters determined based on the recorded images can be further improved, particularly the accuracy of the geometry of the vehicle's longitudinal axis of travel determined based on the recorded images.

[0020] The embodiments of the present invention will now be described with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 A schematic plan view of a measuring station with motor vehicles and calibration equipment is shown.

[0022] Figure 2 A schematic plan view of a measuring station having a motor vehicle and a positioning device for positioning calibration according to the present invention is shown.

[0023] Figure 3 The diagram illustrates the axle geometry of a motor vehicle. Detailed Implementation

[0024] Figure 1 A schematic plan view of a measuring station 2 with a motor vehicle 4 equipped with a driver assistance system 16 is shown. The driver assistance system 16 has at least one sensor 18. The sensor 18 may be, for example, an image recording device (“camera”) and / or a radar sensor.

[0025] The calibration device (“calibration tool”) 20 is positioned in front of the motor vehicle 4.

[0026] Figure 1 The calibration device 20 shown includes a central calibration plate 22. For example, a calibration plate 22 is formed on the calibration plate 22. Figure 1 An invisible optical pattern is provided, which can be optically detected by the sensor 18 of the driver assistance system 16 in order to calibrate the sensor 18 and / or the driver assistance system 16. In the case of a radar sensor, the calibration plate 22 is designed to reflect radar radiation.

[0027] In order to properly calibrate sensor 18 and / or driver assistance system 16, calibration device 20 with calibration plate 22 must be positioned in front of motor vehicle 4 at a predetermined position and orientation.

[0028] Figure 2 A schematic plan view of a measuring station 2 with a motor vehicle 4 and a positioning device 7 according to the invention for positioning calibration device 20 is shown.

[0029] The positioning device 7 according to the invention includes at least one image recording device 6a, 6b, which is designed for optically detecting a motor vehicle 4, particularly the characteristic features of the motor vehicle 4, and providing 3D information about the optically detected characteristic features of the motor vehicle 4.

[0030] The at least one image recording device 6a, 6b may include, for example, a stereo camera that can record three-dimensional images of the motor vehicle 4.

[0031] The at least one image recording device 6a, 6b may specifically include a first image recording device 6a and a second image recording device 6b.

[0032] The first image recording device 6a may be arranged, for example, at the front of the motor vehicle 4, to substantially optically detect the front view of the motor vehicle 4. The second image recording device 6b may be arranged, for example, at the side of the motor vehicle 4, to substantially optically detect the side view of the motor vehicle 4. The side view of the motor vehicle 4 may in particular include images of the wheels 3 and 5 of the motor vehicle 4.

[0033] The only additional image recording device (“second image recording device”) 6b can be arranged on one side next to the motor vehicle 4, such as... Figure 2 As shown in the image.

[0034] In an alternative embodiment not explicitly shown in the figures, additional image recording devices 6b may be arranged on each side of the vehicle 4. Therefore, a total of three or more image recording devices 6a, 6b may be present at the measuring station 2.

[0035] The positioning device 7 according to the invention further includes an evaluation device 8, which is designed to receive 3D information, particularly 3D images, from at least one image recording device 6a, 6b, and to evaluate the 3D information or 3D images provided by the at least one image recording device 6a, 6b in order to determine the position of the calibration device 20 in front of the motor vehicle 4 required for calibrating the driver assistance system 16. The results can be displayed on a display device 10, which may include, for example, a screen and / or a printer.

[0036] 3D information or 3D images can be transmitted wirelessly, such as via WLAN or Bluetooth data connection, or wiredly from at least one image recording device 6a, 6b to the evaluation device 8.

[0037] In order to properly position the calibration device 20, which is used to calibrate the driver assistance system 16, in front of the motor vehicle 4, the motor vehicle 4 drives at a low speed toward at least one image recording device 6a, 6b, as follows: Figure 2 The dashed line representing the portion of the vehicle 4 is shown in the diagram.

[0038] While the motor vehicle 4 is moving toward at least one image recording device 6a, 6b, images of the motor vehicle 4 are recorded using the at least one image recording device 6a, 6b, particularly images containing characteristic features of the motor vehicle 4. Characteristic features of the motor vehicle 4 may include, for example, manufacturer markings mounted on the motor vehicle 4, lighting devices of the motor vehicle 4, exterior rearview mirrors, bumpers, and / or antennas.

[0039] The information contained in the recorded image is provided to the evaluation device 8 as 3D information, for example, in the form of a "3D point cloud".

[0040] The characteristic features contained in 3D information can be identified by using known optical feature recognition algorithms (“feature recognition algorithms”) and / or artificial intelligence methods, such as neural networks.

[0041] For example, the so-called FAST algorithm can be used to identify characteristic features, as described in Edward Rosten and Tom Drummond's publication "Machine learning for high speed corner detection," in 9th European Conference on Computer Vision, Vol. 1, 2006, pp. 430-443, and Edward Rosten, Reid Porter, and Tom Drummond's "Faster and better: a machine learning approach to corner detection," in IEEE Trans. Pattern Analysis and Machine Intelligence, 2010, Vol. 32, pp. 105-119.

[0042] However, other known algorithms can also be used. These algorithms include, for example, those known by the names Harris, ORB, SIFT, SURF, and "Gaussian difference".

[0043] During the movement of the motor vehicle 4 toward at least one image recording device 6a, 6b, the evaluation device 8 specifically tracks the motion of at least one characteristic feature in the recorded 3D image.

[0044] First, the geometrical travel axis FA of the motor vehicle 4 is determined based on the 3D information provided to the evaluation device. The geometrical travel axis FA extends longitudinally through the motor vehicle 4 and indicates the direction of travel of the motor vehicle 4 when traveling in a straight line.

[0045] The geometric driving axis FA, specifically, extends from the center point M of the rear axle H of vehicle 4 to point P in front of vehicle 4, where a straight line extending along the toe angle of the rear wheel 5 of vehicle 4 intersects, as shown below. Figure 3 As shown.

[0046] The geometrical driving axis FA is usually different from the geometrical longitudinal axis L of the vehicle 4. However, in an intact vehicle 4, it should not deviate too much from the geometrical longitudinal axis L of the vehicle 4.

[0047] At sufficiently low speeds, such as 5 km / h, and especially 3 km / h or lower, the geometric travel axis FA is a tangent to all the following trajectories along which all points on the vehicle body 4 move.

[0048] Therefore, by observing the motion of the motor vehicle 4, the geometrical travel axis FA can be determined without directly measuring the toe angle of the rear wheel 5 of the motor vehicle 4.

[0049] Additionally, the distance 'a' between the rear axle H and the front end F of the vehicle 4 is determined based on 3D information provided to the evaluation device 8 by at least one image recording device 6a, 6b. Specifically, the distance 'a' between the rear axle H and the front end F of the vehicle 4 can be determined based on images recorded by the image recording device 6b arranged on the side of the vehicle 4.

[0050] The front end F of the motor vehicle 4 is defined as the foremost point of the motor vehicle 4. The position of the rear axle H of the motor vehicle 4 can be determined based on the position of the rear wheel 5 optically detected by at least one image recording device 6a, 6b. The rear wheel 5 can be identified in the image recorded by at least one image recording device 6a, 6b using known pattern recognition algorithms and / or artificial intelligence methods, such as using a neural network.

[0051] If the image recording device 6b cannot detect the front end F and the rear wheel 5 of the motor vehicle 4 at the same time, the distance between the front end F and the rear wheel 5 of the motor vehicle 4 can also be determined based on the time interval between the detection of the front end F and the rear wheel 5 of the motor vehicle 4 by the image recording device 6b and the estimated speed of the motor vehicle 4.

[0052] After the motor vehicle 4 stops in front of the positioning device 7, the evaluation device 8 determines the position and orientation of the stopped motor vehicle 4 relative to the at least one image recording device 6a and 6b based on the 3D information provided to the evaluation device 8 by at least one image recording device 6a and 6b.

[0053] Therefore, the evaluation device 8 can determine the position of the calibration device 20 based on previously determined parameters, in particular based on the current position and orientation of the motor vehicle 4 in front of at least one image recording device 6a, 6b, the orientation of the driving axle FA of the motor vehicle 4, and the distance a between the front end F and the rear axle H of the motor vehicle 4, so that the sensor 18 of the driver assistance system 16 of the motor vehicle 4 can be properly calibrated.

[0054] The position of the calibration device 20 calculated in this way can be displayed on the display device 10 so that personnel can read the position of the calibration device 20 determined by the evaluation device 8 from the display device 10 and position the calibration device 20 at that position.

[0055] Alternatively, the calibration device 20 may be designed to independently (“autonomously”) position itself in front of the calculated location in front of the vehicle 4. In this case, the evaluation device 8 may be coupled to the calibration device 20 to transmit the position determined by the evaluation device 8 for the calibration device 20 to the calibration device 20, so that the calibration device 20 can independently position itself in front of the vehicle 4 as calculated by the evaluation device 8.

[0056] At least one of the image recording devices 6a, 6b and / or the evaluation device 8 may be mounted on the calibration device 20 such that it can be positioned together with the calibration device 20 in front of the motor vehicle 4 at the measurement station 2.

[0057] The image recording device 6b, which is not mounted on the calibration device 20, can be arranged on or at the measurement station 2 such that the calibration device 20 is located within the field of view of the image recording device 6b.

[0058] In this configuration, the evaluation device 8 can determine not only the position and orientation of the vehicle 4 based on the 3D information provided by the image recording device 6b, but also the position and orientation of the calibration device 20 on the measuring station 2. This allows the evaluation device 8 to check whether the calibration device 20 is positioned and oriented correctly in front of the vehicle 4 and to provide corresponding feedback on the display device 10.

[0059] In this way, the reliability and accuracy of the positioning of the calibration device 20 in front of the motor vehicle 4 can be further improved, and the risk of incorrect calibration of the sensor 18 due to incorrect positioning of the calibration device 20 on the measuring station 2 can be reduced.

[0060] The method according to the invention may further include, in particular, creating a so-called depth map of the vehicle 4 after the vehicle 4 has stopped in front of at least one image recording device 6a, 6b. The depth map contains information about the distances to corresponding points on the respective image recording devices 6a, 6b for a plurality of points, particularly including characteristic features of the vehicle 4.

[0061] With the help of such a depth map, 3D information provided by at least one image recording device 6a, 6b can be evaluated particularly efficiently. In particular, objects such as motor vehicle 4 can be identified in the depth map, and the symmetry of the object can be determined.

[0062] The lateral position of the geometric travel axis FA of motor vehicle 4 at the center of motor vehicle 4 can also be determined based on the information contained in the depth map.

[0063] In addition, the distance d between the front end F of the motor vehicle 4 and the image recording device 6a arranged in front of the motor vehicle 4 can be obtained from the depth map.

[0064] The positioning device 7 according to the invention and the method according to the invention simplify the positioning of the calibration device 20 in front of the motor vehicle 4, which is configured to calibrate at least one sensor 18 of the driver assistance system 16. In particular, the positioning device 7 according to the invention and the method according to the invention eliminate the need to mount a measuring panel (“target”) on the motor vehicle 4. Furthermore, the accuracy of the positioning of the calibration device 20 in front of the motor vehicle 4 can be improved, and the risk of incorrect positioning of the calibration device 20 in front of the motor vehicle 4 can be minimized.

Claims

1. A method for positioning a calibration device (20) configured for calibrating a driver assistance system (16) in front of a motor vehicle (4), wherein the method comprises: (a) Using the motor vehicle (4) to drive toward at least one image recording device (6a, 6b); (b) During the movement of the motor vehicle (4), the characteristic features of the motor vehicle (4) are optically detected using the at least one image recording device (6a, 6b), and 3D information about the optically detected characteristic features of the motor vehicle (4) is provided. (c) Determine the driving longitudinal axis (FA) of the motor vehicle (4) by evaluating the provided 3D information; (d) Determine the distance (a) between the front end (F) and the rear axle (H) of the motor vehicle (4) by evaluating the provided 3D information; (e) Park the motor vehicle (4) in front of the at least one image recording device (6a, 6b); (f) Determine the position of the stopped motor vehicle (4) in front of the at least one image recording device (6a, 6b); (g) Determine the position of the calibration device (20) in front of the motor vehicle (4) for calibrating the driver assistance system (16) according to previously determined parameters, wherein the parameters include the driving longitudinal axis (FA) of the motor vehicle (4), the distance (a) between the front end (F) and the rear axle (H) of the motor vehicle (4), and the position of the motor vehicle (4) in front of the at least one image recording device (6a, 6b).

2. The method according to claim 1, wherein, Optical detection of the characteristics of the motor vehicle (4) includes recording a 3D image of the motor vehicle (4) and identifying the characteristics in the recorded 3D image.

3. The method according to claim 2, wherein, The method includes tracking the motion of characteristic features in the recorded 3D images.

4. The method according to any one of the preceding claims, wherein the method comprises: After the motor vehicle (4) is parked in front of the at least one image recording device (6a, 6b), a depth map of the motor vehicle (4) is created, wherein the depth map contains information about the distance between the characteristic features of the motor vehicle (4) and the at least one image recording device (6a, 6b).

5. The method according to any one of the preceding claims, wherein the method comprises: Display the position of the calibration device (20) calculated in step (g) and / or the calculated position of the calibration device (20) in front of the motor vehicle (4).

6. A positioning device (7) for positioning a calibration device (20) in front of a motor vehicle (4), wherein the calibration device (20) is configured to calibrate a driver assistance system (16), wherein, The positioning device (7) includes: At least one image recording device (6a, 6b) is designed to optically detect characteristic features of the motor vehicle (4) and provide 3D information about the optically detected characteristic features of the motor vehicle (4); An evaluation device (8) is designed to evaluate 3D information provided by the at least one image recording device (6a, 6b) to determine the position of the calibration device (20) in front of the motor vehicle (4) required for calibrating the driver assistance system (16).

7. The positioning device (7) according to claim 6, wherein, The positioning device (7) is designed for: (A) During the period when the motor vehicle (4) is driving toward the at least one image recording device (6a, 6b), the characteristic features of the motor vehicle (4) are optically detected and 3D information about the optically detected characteristic features of the motor vehicle (4) is provided; (B) Determine the driving longitudinal axis (FA) of the motor vehicle (4) by evaluating the provided 3D information; (C) Determine the distance (a) between the front end (F) and the rear axle (H) of the motor vehicle (4) by evaluating the provided 3D information; (D) After the movement of the motor vehicle (4) stops, determine the position of the motor vehicle (4) in front of the at least one image recording device (6a, 6b).

8. The positioning device (7) according to claim 6 or 7, wherein, The at least one image recording device (6a, 6b) is mounted on the calibration device (20).

9. The positioning device (7) according to claim 6 or 7, wherein, The at least one image recording device (6a, 6b) is arranged such that the calibration device (20) is located within the field of view of the at least one image recording device (6a, 6b).

10. The positioning device (7) according to any one of claims 6 to 9, wherein, The at least one image recording device (6a, 6b) is a first image recording device (6a, 6b), and wherein the positioning device (7) has a second image recording device (6a, 6b), wherein the first image recording device (6a) is specifically designed for recording an image of the front view of the motor vehicle (4); and / or The second image recording device (6b) is specifically designed to record images of the side view of the motor vehicle (4).

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