WO2020043856A1

WO2020043856A1 - Method and device for checking the setting of headlights of motor vehicles

Info

Publication number: WO2020043856A1
Application number: PCT/EP2019/073153
Authority: WO
Inventors: Wolfgang Brunk; Severin Krieter; Marc Zeißler
Original assignee: Visicon Automatisierungstechnik Gesellschaft Mit Beschränkter Haftung
Priority date: 2018-08-29
Filing date: 2019-08-29
Publication date: 2020-03-05
Also published as: DE112019004264A5; DE102018121144B3

Abstract

In order to check the setting of headlights (2) of motor vehicles (3), the respective motor vehicle (3) is aligned with respect to a test surface (6) arranged at a distance in front of the motor vehicle (3). A position marking (29) is projected onto the test surface (6) by means of a laser scanner (13). In doing so, a position of the position marking (29) on the test surface (6) is adjusted as a function of a headlight position of the respective headlight (2) to be adjusted with respect to the test surface (6) by actuating the laser scanner (13). With the respective headlight (2) to be adjusted, a light distribution (8) is projected onto the test surface (6), and a relative position of the light distribution (8) on the test surface (6) is determined with respect to the position marking (29).

Description

METHOD AND DEVICE FOR CHECKING THE SETTING OF

HEADLIGHTS OF MOTOR VEHICLES

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method for checking the adjustment of headlights of a motor vehicle and to a device for performing such a method. In particular, the invention relates to a method with the features of the preamble of claim 1 and to an apparatus for carrying out such a method with the features of the preamble of claim 13.

STATE OF THE ART

According to the German StVZO, an adjustable flat surface is to be used for the adjustment of the headlights of motor vehicles. This test area should be light colored and provided with a central mark and a horizontal dividing line. The test area must be arranged perpendicular to the base of the motor vehicle and perpendicular to the longitudinal plane of the vehicle. The distance between the test area and the headlamp to be adjusted must be 10 m to give the values specified in the StVZO for the correct adjustment of headlamps. The central mark of the test area must lie in the plane parallel to the median longitudinal plane of the vehicle, which runs through the center of the headlight to be adjusted. For each headlight to be adjusted, the dividing line must be set to a predetermined height parallel to the base of the motor vehicle. Then the intensity distribution of the light of the respective headlamp must be set depending on the type of headlamp so that it meets certain requirements with respect to the central mark and the hyphen. For headlights for symmetrical low beam and for fog lights, the highest point of the so-called light-dark boundary must touch the hyphen and over the minimum width of the Test surface should be as horizontal as possible. In the lateral direction, these headlights must be set so that the light distribution is as symmetrical as possible to a vertical line through the central mark. In the case of headlights for asymmetrical dipped beam headlights, the cut-off line to the left of the center must touch the hyphen. The intersection between the left, as horizontally as possible, and the part of the cut-off line that rises to the right, ie the so-called break point, must lie on the vertical through the central mark. The center of the beam of the high beam, however, must be on the central mark.

Other official specifications for the adjustment of headlights of motor vehicles also relate to a light distribution on a test surface to be arranged in front of the respective motor vehicle, on which at least one position marking is attached, the position of which depending on a headlight position of the headlight to be adjusted relative to the test surface is.

In the case of a "measuring wall with profile frame" offered by the applicant, two measuring boards are mounted on a profile frame so that they can be moved by motor in the horizontal and vertical direction. Each of these measuring panels is assigned to the headlights on one side of the respective motor vehicle. To check the setting of a headlight, the respective measuring board, which is provided with a central mark and a hyphen, is first moved to the position specified by the StVZO. Then the respective headlamp is directed onto the measuring board and the measuring board is shifted relative to the light distribution of the headlamp on the measuring board in such a way that the light distribution is arranged according to the regulations relative to the central mark and the separating line. The necessary displacements of the measuring board in the vertical and horizontal direction are recorded and, if necessary, used to adjust the headlamp. In order to ensure the occupational safety of the known measuring wall with the measuring plates that can be moved relative to its profile frame, it must be ensured that nobody is in the moving area of the measuring plates that could be endangered by moving the measuring plates relative to the profile frame. Due to the overall size of the measuring wall, this is very complex.

DE 10 2014 015 796 A1 discloses a method for checking the functionality of a motor vehicle with a headlight. The headlamp comprises a laser for generating light, by means of which a converter for emitting converted light is excited, which is generated by the headlamp for generating a predetermined light distribution on a surface is emitted in a surrounding area of the motor vehicle. The converter can comprise, for example, a crystal element made of Ce: YAG, and it is used to convert the light generated by the laser with a particularly high light intensity in a particularly narrow wavelength range into light in a broader wavelength range, for example into white light with a temperature of 5,500 Kelvin, which is perceived as pleasant by all road users. The specifiable light distribution is set by a control device of the headlamp. In order to check the state of the converter, the control device sets a test pattern that is detected on the surface by means of an optical detection device of the motor vehicle. The detected test pattern is compared with a predetermined reference pattern by an evaluation device of the motor vehicle. The reference pattern is generated by the motor vehicle itself in that a further light distribution is set, recorded and stored as a reference pattern.

DE 10 2014 217 524 A1 discloses a test device for testing safety-related devices in a motor vehicle, in particular in the form of a headlight adjustment device with modular test devices for testing surroundings detection systems of the motor vehicle. The test device comprises a test unit that can be positioned in a surrounding area of a motor vehicle to be tested, and at least one test device for testing a safety device of the motor vehicle. The test device is a projector which depicts a driving situation in order to activate at least one camera-based safety device of the motor vehicle to be tested and to initiate a measurement process, or a device for generating electromagnetic waves that is suitable for this, at least to activate a safety device of the motor vehicle that works on the basis of electromagnetic waves. The latter safety-related device, which works on the basis of electromagnetic waves, can comprise an ultrasound sensor, a radar sensor and / or a radio wave sensor.

DE 10 2015 223 500 A1 discloses a method for testing the functionality of a light device in a motor vehicle. At least one light cone, which is created by the light device, is projected onto an object in front of the vehicle. An image capture device, which is attached outside the vehicle, captures an image that represents the projection of the light cone onto the object and a view of a part of the vehicle with the light device. From the image distance-based information of the projected Light cone and the vehicle is determined, and the functionality of the lighting device is checked on this basis.

A lighting device for a motor vehicle is known from DE 10 2016 106 649 A1, which comprises a plurality of light sources and a radiation means for electromagnetic radiation. The light sources are designed to emit electromagnetic radiation which is visible to people, while the emitting means is designed to emit electromagnetic radiation which is not visible to people. The lighting device further comprises a detection means for the electromagnetic radiation emitted by the radiation means and an adjustment means. The detection means is designed to give a signal to the setting means, which includes an indication of a beam direction of the invisible electromagnetic radiation, and the setting means is designed to determine a beam direction of the invisible electromagnetic radiation and a beam direction of the visible electromagnetic radiation influenced by the signal. This makes it possible to set the beam direction on the basis of the invisible electromagnetic radiation, in particular a setting of the beam direction using the detection means while driving.

A measuring device for measuring the light distribution of a headlight of a motor vehicle is known from JP H04-38 436 A. The device has a test surface and a CCD camera aligned thereon. The CCD camera records the light distribution that the headlamp forms over the test area. In order to align the camera in a defined manner with respect to the test area, a laser beam is projected parallel to the optical axis of the camera with a laser marker, and the alignment of the camera perpendicular to the test area in order to avoid distortions in the images of the camera is carried out using the laser beam .

OBJECT OF THE INVENTION

The invention is based on the object of demonstrating a method and a device for checking the setting of headlights of motor vehicles, in which the requirements for occupational safety can be met more easily than in the case of motor-driven measuring boards. SOLUTION

The object of the invention is achieved by a method with the features of patent claim 1 and by an apparatus for carrying out this method with the features of patent claim 13. Preferred embodiments of the method and device according to the invention are defined in the dependent claims.

DESCRIPTION OF THE INVENTION

In a method according to the invention for checking the setting of headlights of motor vehicles with the steps of aligning the respective motor vehicle with respect to a test surface arranged at a distance in front of the motor vehicle, setting a position of a position marking on the test surface depending on a headlight position of the respective headlight to be adjusted relative to the Test surface, projecting a light distribution with the headlight to be adjusted in each case onto the light surface and qualitatively and / or quantitatively determining a relative position of the light distribution on the test surface compared to the position marking, the position marking is projected onto the test surface with a laser scanner, the position of the position marking on the Test area is set by controlling the laser scanner.

The position marking can in particular be a target position of the light distribution that is dependent on the headlight position, and the relative position of the light distribution on the test surface compared to the position marking can be determined in the form of deviations of the light distribution from this target position.

The position marking on the test area can specifically be a central mark and a horizontal hyphen. Depending on the determination to be used for the adjustment of the respective headlamp, however, other and / or additional position markings can also be projected onto the test surface with the laser scanner. When setting the position of the position marking on the test surface, according to the invention no measuring wall or measuring board having the test surface is moved, but the position marking projected onto the test surface with the laser scanner is activated by actuating the Laser scanners changed their position on the test surface until they reached their desired setting. Accordingly, there is no risk of injury from collisions with a measuring wall or measuring board that is moved relative to a profile frame.

The laser scanner is used to pivot a laser beam or its point of impact onto the test surface in such a way that a light distribution of the laser light results which is related to a human viewer or a camera with a normal image frequency of no more than 25 Hz, 50 Hz or 100 Hz the individual positions of the point of impact of the laser on the test surface cannot be resolved in time. A speed when swiveling the laser beam in relation to the test surface is sufficient for this, which can be easily achieved with conventional laser scanners. At the same time, the speed when swiveling the laser beam also ensures occupational safety in the area of the test area. Even if the laser beam struck a human eye there, this would only be the case for a very short time. Even with a relatively intense laser beam, as is required for projecting the position marking onto the test surface illuminated by the headlight with its light distribution, so that the position marking remains visible, there is eye safety.

The headlight position of the headlamp to be adjusted relative to the test area, which is decisive for the position in which the position marking is to be projected onto the test area, can be determined automatically in the course of the method according to the invention by taking a headlight image of the headlight and analyzing this headlight image. In particular, for this purpose the headlight image can be recorded when the headlight is illuminated and a position of a center of gravity of a brightness distribution in the image of the headlight can be equated with the position of the headlight and the headlight position can be inferred therefrom. For the headlamp position of the headlamp in relation to the test surface, it is not the external dimensions that are decisive, but the central position of its light exit surfaces. If the respective motor vehicle with its longitudinal median plane is aligned normal to the test surface and is at a defined distance from the test surface, a camera is sufficient to determine the headlight position of the headlight to be adjusted, which, for example, takes a picture of the illuminated headlight from the test surface. No stereo camera arrangement is required to determine the headlight position of the headlight. Alternatively, the headlamp position of the headlamp to be adjusted relative to the test surface can be aligned by aligning another laser beam from another laser scanner Reference point of the headlamp can be determined. This laser beam can be of very low light intensity and can therefore be fundamentally eye-safe. The laser beam can be formed from red light with a wavelength above 600 nm. The further laser scanner can be controlled with an operating unit, for example a joystick, in order to pivot the laser beam until it is aligned with the respective reference point of the headlight. From the associated position of the laser scanner, in conjunction with the specified basic orientation and position of the motor vehicle relative to the test area, a clear conclusion can be drawn as to the headlight position of the headlight relative to the test area. The conditions for this are particularly favorable if the further laser beam is directed with the further laser scanner from the test surface onto the reference point of the headlight.

In order to ensure that the laser beam does not hit a sensitive object, for example a human eye, for long periods of time with high intensity, the laser beam directed by the laser scanner onto the test surface can be switched off automatically if it is found that a scanner the laser scanner is at rest or when an object enters a monitoring area in front of the laser scanner. To determine whether an object enters the monitoring area in front of the laser scanner, very simple monitoring measures are sufficient, which can be implemented inexpensively.

The light of the laser beam emitted and pivoted by the laser scanner can in principle have any wavelength. If the position marking formed with the laser scanner on the test surface is not detected with the human eye but with a camera, the wavelength can be in an invisible range in which the camera is sensitive, however. However, for reasons of occupational safety, for example, the wavelength of the laser beam, even when the position marking is recorded with a camera, is preferably in the visible range, ie in particular between 480 and 680 nm. In the practical implementation of the method according to the invention, it has proven to be advantageous to form the pivoted laser beam emitted by the laser scanner from green light, by which light in a wavelength range from 500 nm to 600 nm is meant. The advantage of green light is the good visibility of the position marking projected with it, even with light intensities of the laser beam that are harmless with regard to eye safety. Commercially available laser scanners can be controlled in a simple manner in order to project the position marking in any shape and position onto the test surface. In particular, the position of the projected position marking on the test area can be easily shifted in order to comply with the requirements of the Road Traffic Licensing Regulations or other regulations that must be observed when adjusting headlights of motor vehicles.

To make it easier to adjust the headlights of a motor vehicle, the position marking can be adapted to special features of the specific light distribution of the respective headlight. In order to determine the position of the point of inflection of the cut-off line in the case of headlights for asymmetrical low beam, the position marking can comprise at least one line which has a break point and whose course is adapted to the specific course of the cut-off line of the specific light distribution of the respective headlight is. In this context, an inflection point of a line of the position marking is to be understood to mean any change in direction between two straight line sections of the line, even if this change in direction runs, for example, in an arc. For the adjustment of the high beam, however, the position marking can comprise a line which is closed in a ring and extends around the area around a central mark in which the light beam of the high beam is arranged when the headlight is correctly adjusted. This means that the position marking is not only arranged depending on the headlight position of the headlight to be adjusted relative to the test surface on the test surface, but the shape of the position marker can also be adapted to the specific light distribution of the headlight to be adjusted with the help of the controlled laser scanner.

Specifically, the position marking can be formed depending on a type and / or an operating state of the headlight to be adjusted in each case. This type and / or operating status can be specified manually or using a test program. However, within the scope of the method according to the invention, it is also possible to determine the type and / or the operating state of the headlamp to be adjusted in each case by taking a distribution image of the light distribution of the headlamp on the test surface and analyzing this distribution image. In this way, the course of a light-dark boundary can be determined as the maximum intensity gradient of the light distribution over the test area. Furthermore, a center of gravity of the light distribution or a line around the area of the highest light intensities in the light distribution on the test surface can be determined by image processing of the distribution image. The cut-off line has a break point for all headlights for asymmetrical low beam. The light-dark boundary can, however, deviate from the course of two straight lines intersecting at the break point. These deviations can be caused by the type of headlight. In order to easily adjust a headlamp with such deviations, a position marking can be projected onto the test surface, which corresponds to the course of the light-dark boundary with the headlamp correctly adjusted. In order to eliminate a misalignment, the actual light-dark limit of the headlamp must be overlapped with the projected position marking. This is often much easier than the direct application of the StVZO. Similar peculiarities depending on the type of the respective headlamp also occur with other headlamps or operating states, ie for example the symmetrical low beam or high beam.

In the method according to the invention, the relative position of the light distribution relative to the position marker projected onto the test surface depending on the headlight position of the respective headlight to be adjusted relative to the test surface by moving the projected position marker until the light distribution is aligned with the position marker in accordance with a regulation, and can be detected the necessary shifts in the projected position marker can be determined quantitatively. These displacements can be detected by comparing the different positions of the laser scanner before and after the displacement. In a development of the method according to the invention, the relative position of the light distribution of the headlight compared to the position marking can be automatically determined by taking a superimposed marking and distribution image of the position marking and the light distribution on the test surface and analyzing this marking and distribution image. According to the StVZO, for example, the conformity of the respective headlight or its light distribution with the specifications is checked visually. But even then there is nothing to be said against automatically determining the relative position of the light distribution of the headlight with respect to the position marking. Rather, this automatic determination of the relative position can be used to control an automatic adjustment of the respective headlight, which can then be checked by a visual check. To calibrate a camera to record the superimposed marking and distribution image, the test area can be provided with a known two-dimensional reference pattern, for example by arranging a board with the reference pattern on the test area. Specifically, the reference pattern can be a line pattern of horizontal and vertical lines crossing at right angles. If a sample image of the reference pattern is then registered with the camera, then the distortion is determined from the sample image with which the test area is imaged in the images of the camera. If the absolute position of the reference pattern is known, the camera can also be positioned absolutely, ie with respect to certain positions on the test surface. The absolute position of the reference pattern can in particular be that relative to a calibration frame, which is defined in front of the test area, for example with a so-called centering stand, from which two parallel laser beams are emitted at a defined height parallel to a footprint for the respective motor vehicle.

In addition, this development of the method according to the invention can be used to check whether the headlight to be adjusted has photometric specifications, for example a maximum luminous flux that is emitted across a center of the road, or a maximum illuminance above a horizontal boundary line running at a certain height or a maxi - Male headlight range on the road, already adhering to it or how it must be adjusted so that it complies with these specifications. For a corresponding illuminance calibration of the camera, it can be used to register a reference image of a reference light distribution of a reference headlight, from which known luminous fluxes originate. As an alternative, the luminous flux incident on a certain sub-area of the test area from any headlight can be detected with a lux meter and linked to the signal of the camera for this sub-area of the test area. At least a maximum or at least a comparatively large as well as a comparatively small luminous flux from the respective headlight are preferably taken into account for the illuminance calibration of the camera.

In order to arrange the respective motor vehicle with the desired alignment of its longitudinal center plane or even better its direction of travel at the desired distance from the test surface, it can be moved to a centering and / or measuring stand and aligned with devices of the centering and / or measuring stand. A chassis measuring stand can be used as such a centering and / or measuring stand. Insofar as this chassis measurement stand does not directly align and adjust the longitudinal center plane of the respective motor vehicle. speaking, it can also not be arranged perpendicular to the test area, since the chassis measuring stand nevertheless allows the orientation of the longitudinal center plane of the motor vehicle to be determined. This alignment can then be taken into account when the method is carried out further, ie when determining the headlight position of the headlights of the motor vehicle and the projection of the position markings onto the test area which is coordinated therewith. In addition, the orientation of the direction of travel of the respective motor vehicle relative to the test surface, which runs to the longitudinal center plane of the vehicle at the so-called driving axis angle, is determined and taken into account when setting the position of the position marking on the test surface, because the headlights of a motor vehicle are ideally not in relation to its longitudinal center plane, but instead aligned with its direction of travel. In this case, a driving axle angle can be used that was measured beforehand on a chassis measuring stand that was separated from a centering stand for aligning the longitudinal center plane of the respective motor vehicle when carrying out the method according to the invention. It goes without saying that non-compliant relative positions of the light distribution with respect to the position marking, for example deviations of the light distribution from the position marking indicating a desired position of a feature of the light distribution, have to be compensated for by adjusting the headlight to be adjusted relative to the rest of the motor vehicle. This adjustment, depending on the specific relative position, can, as already indicated, take place automatically and be checked visually.

In order to calibrate the laser scanner with which, in the method according to the invention, not only the position marking can be projected onto the test surface in a specific position, but which can also be used to measure the relative position of the light distribution with respect to the position marking, one can use the laser scanner one after the other vertical line and a horizontal line are projected onto the test surface and moved across the test surface in the horizontal and vertical directions. If it is registered with point sensors arranged in the test area when they are hit by the laser beam of the laser scanner, it can be concluded from the distribution of the point sensors over the test area and the associated controls or positions of the laser scanner, such as the laser scanner must be controlled in order to reach a certain point on the test surface with its laser beam. If this knowledge is used in the future control of the laser scanner, the laser scanner is calibrated. Alternatively, to calibrate the laser scanner, the test surface can be provided with a known two-dimensional reference pattern and a reference mark comprising a plurality of reference points can be projected onto the test surface with the laser scanner, a relative position of the reference points with respect to the reference pattern being registered. Then, from the controls or positions of the laser scanner associated with the reference points in conjunction with the relative position of the reference points with respect to the reference pattern, it can be concluded how the laser scanner must be controlled in order to use its laser beam to determine a specific point within the reference pattern and to achieve on the test area. For this calibration too, the test surface can be provided with the known two-dimensional reference pattern by arranging a board with the reference pattern in a defined absolute position on the test surface. With this alternative calibration of the laser scanner, no special facilities are required on the test area. Rather, it is sufficient that the test surface is correctly aligned and has a defined and sufficiently large reflectivity. In a device according to the invention for carrying out the method according to the invention with a measuring wall having a test surface and a controller which is designed to set a position of a position marker on the test surface, a laser scanner is provided to project the position marker onto the test surface, and the controller is designed to adjust the position of the position marker on the test surface by actuating the laser scanner. The measuring wall of the test device according to the invention can thus in particular be stationary. This eliminates the risk of movement from the measuring wall or from measuring boards of the measuring wall.

The device according to the invention can include position detection devices which are designed to detect the headlight position of the headlight to be adjusted relative to the test surface. Accordingly, the control of the device according to the invention can be designed to set the position of the position marking on the test surface depending on the detected headlight position of the headlight to be adjusted relative to the test surface.

The position detection devices can have a camera directed away from the test surface and can be designed to position the headlight of the headlight to be adjusted relative to the test surface while taking a headlight image of the headlight and analyzing this headlamp image to determine. Alternatively, the position detection devices can have a further laser scanner directed away from the test surface and can be designed to determine the headlight position of the headlight to be adjusted relative to the test surface by aligning a further laser beam from the further laser scanner to a reference point of the headlight. Specifically, the headlamp position of the headlamp results from the position of the further laser scanner when its laser beam strikes the reference point of the headlamp when it is at a defined horizontal distance from the further laser scanner.

To further increase the operational safety of the device according to the invention, safety devices can be designed to switch off a laser beam from the laser scanner if the safety devices determine that a scanner of the laser scanner is at rest and / or that an object enters a monitoring area in front of the laser scanner. Furthermore, for the reasons already explained in connection with the method according to the invention, the laser scanner can have a laser which emits a laser beam from green light, ie. H. from light with wavelengths in the range from 500 nm to 600 nm, aimed at the test surface.

An alignment and / or alignment detection device can be arranged at a distance in front of the test surface of the measuring wall and can be designed to adjust and / or determine an alignment of a longitudinal center plane of the vehicle and / or a direction of travel of the respective motor vehicle running at an angle of the driving axis relative to the test surface. In particular, this alignment and / or alignment detection device can be a centering stand or a chassis measuring stand for the respective motor vehicle, in which the motor vehicle is oriented in a defined manner anyway and which is designed to adjust the driving axis angle, i. H. to determine the angle between the longitudinal plane of the vehicle and the direction of travel of the rear axle of the respective motor vehicle. This alignment and determination takes place in the device according to the invention relative to the test surface.

Furthermore, headlight detection devices can be provided, which are designed to detect a type and / or an operating state of the headlight to be adjusted in each case. The controller can then be designed to form the position marking depending on the recognized type and / or operating state of the headlight to be adjusted in each case. The headlight detection devices can specifically have a camera directed at the test surface and can be designed to accommodate the type and / or the operating state of the headlight to be adjusted in each case by taking a distribution image of the light distribution on the test surface with the camera and analyzing this distribution image.

Furthermore, the device according to the invention can have relative position determination devices which have a shifting device for shifting the position marking projected onto the test surface with the laser scanner in response to manual command inputs, and are designed to shift the position mark between the start position and the projected onto the test surface with the laser scanner to quantitatively record an end position of the position marking projected onto the test surface with the laser scanner. Alternatively, the device according to the invention can have relative position determination devices which have the same or a different camera directed at the test surface and are designed to deviate the light distribution from the position marking by recording a superimposed marking and distribution image of the position marking and the light distribution on the test surface and analyzing this marker and distribution image to determine. The overlaid marking and distribution images recorded by the relative position determination devices are also suitable for documenting the successful correct setting of the respective headlight.

The device according to the invention can also have automatic adjustment devices which are designed to set the relative position of the light distribution to the position marking in accordance with the regulations and in particular to compensate for deviations in the light distribution from a position marking indicating a desired position by adjusting the headlight to be adjusted depending on these deviations. Even if this compensation takes place automatically, it can be checked visually by looking at the result of the compensation on the test surface. Point sensors can be arranged in the test area of the measuring wall of the device according to the invention, which register when they are hit by the laser beam of the laser scanner. These point sensors can be connected to the control of the device in order to automatically calibrate the laser scanner with the aid of the point sensors. Specifically, two of the point sensors can be arranged one above the other at a vertical distance and two of the point sensors can be arranged next to one another in the test area at a horizontal distance. In particular Four or more point sensors can be arranged in a regular orthogonal and vertically and horizontally aligned grid.

With the aid of the point sensors arranged one above the other in the vertical distance, it can be determined on the one hand how much, ie. H. by how much, the setting of the laser scanner has to be changed in order to overcome this vertical distance when projecting a horizontal line onto the test surface. On the other hand, the vertically stacked point sensors can be used to check whether a vertical line actually runs vertically, because this line runs across both vertically stacked point sensors at a time. The same applies to the two point sensors arranged horizontally next to each other. They can be used to determine how much the laser scanner needs to be adjusted to overcome its horizontal distance, and can be used to check the exact horizontal alignment of a horizontal line that is projected onto the test surface with the laser scanner.

Advantageous further developments of the invention result from the patent claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the description are only examples and can have an alternative or cumulative effect without the advantages necessarily having to be achieved by embodiments according to the invention. Without changing the subject matter of the attached claims, the following applies to the disclosure content of the original application documents and the patent: further features are the drawings - in particular the geometries shown and the relative dimensions of several components to one another and their relative arrangement and active connection - can be seen. The combination of features of different embodiments of the invention or of features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby suggested. This also applies to those features which are shown in separate drawings or mentioned in the description. These features can also be combined with features of different patent claims. Features in the patent claims can also be omitted for further embodiments of the invention. The features mentioned in the patent claims and the description are to be understood with regard to their number in such a way that exactly this number or a greater number than the mentioned Number is available without the explicit use of the adverb "at least". If, for example, a camera is mentioned, this should be understood to mean that exactly one camera, two cameras or more cameras are present. The features cited in the patent claims can be supplemented by other features or be the only features that the respective method or the respective device has.

The reference numerals contained in the patent claims do not represent any restriction of the scope of the objects protected by the patent claims. They serve only the purpose of making the patent claims easier to understand.

BRIEF DESCRIPTION OF THE FIGURES In the following, the invention is further explained and described with reference to preferred exemplary embodiments shown in the figures.

1 is a schematic view of a device according to the invention for carrying out the method according to the invention for adjusting headlights of motor vehicles. FIG. 2 shows a camera as an embodiment of position detection devices for a headlight position of a headlight of a motor vehicle to be adjusted, which is shown only schematically in FIG. 1.

Fig. 3 shows schematically a laser scanner as an alternative to the camera 12 as

Part of the position detection devices according to FIG. 1. FIG. 4 illustrates a position marking which is used by another laser scanner

1 is projected onto a test surface of a measuring wall depending on the headlight position of a headlight to be adjusted; and

FIG. 5 shows an embodiment of the measuring wall of the device according to the invention with four point sensors arranged in its test surface. FIGURE DESCRIPTION

1 shows a device 1 for checking the setting of headlights 2 of a motor vehicle 3. The device 1 comprises a measuring wall 5 supported on the floor 4 with a test area 6. The test area 6 is typically at a defined distance 7 10 m in front of the headlights 2 of the motor vehicle 3. When checking the setting of the headlights 2, the test surface is illuminated with a single one of the headlights 2 to be adjusted, which results in a light distribution 8 on the test surface 6. This light distribution 8 is aligned with position markings on the test surface 6. The position of the position marking on the test surface 6 is to be adjusted depending on the headlight position of the headlight 2 to be adjusted in the vertical direction and in the lateral direction transverse to the median longitudinal plane of the motor vehicle 3, this median longitudinal plane of the motor vehicle 3 at a horizontal right angle with respect to the Test surface 6 is to be aligned. This alignment of the motor vehicle 3 is brought about by alignment devices 9, which are not shown in detail here. The alignment devices 9 can be part of a chassis measuring stand 10 which is supported on the floor 4. Insofar as the alignment devices 9 do not align the respective motor vehicle 3 with its central longitudinal plane of the vehicle exactly perpendicular to the test area 6, the alignment devices 9 can, however, detect the remaining misalignment, and the misalignment can be taken into account when adjusting the position of the position marking on the test area 6. Instead of the longitudinal center plane of the vehicle, the direction of travel of the rear axle of the respective motor vehicle, which runs under the so-called driving axis angle, can also be taken into account when setting the position of the position marking on the test surface 6. Detection devices 11 are provided for detecting the headlight position of the headlight 2 to be adjusted in each case in the horizontal and vertical direction parallel to the test surface 6. As shown separately in FIG. 2, the detection devices 11 can comprise a camera 12, with which an image of the headlight 2 to be adjusted and illuminating the test surface 6 is recorded from the measuring wall 5. The headlight position of the headlight 2 that is sought can be clearly derived from this picture, the headlight position that is sought can be equated to the center of gravity of a light exit surface of the headlight 2. The center of gravity of the light exit surface of the headlight 2 can be determined with the emerging light intensity or with such a weighting without weighting the surface portions of the light exit surface. The position marking is then projected onto the test surface 6 with a laser scanner 13 depending on the determined headlight position of the headlight. The laser scanner 13 comprises a laser 14, which at any time essentially hits the test surface 6 in a point-like manner 15 sends out. Focusing optics (not shown here) can focus the laser beam 15 on the test surface 6. Furthermore, the laser scanner 13 has a scanner 16 in order to shift the point of incidence of the laser beam 15 onto the test surface 6. For this purpose, the scanner 16 has two scanner mirrors 17 and 18, which are each pivotable about a pivot axis 19 or 20. The laser scanner 13 is controlled by a controller 21. Specifically, the controller 21 ensures that the scanner mirrors 17 and 18 are swiveled so rapidly that the position marking is formed on the test surface 6. For this purpose, the laser beam 15 must be swiveled so quickly that the position marking when viewing the test area 6 is no longer resolved into the individual points of incidence of the laser beam 15, neither by a human viewer nor by a camera 22, which points to the test area

6 is directed. The camera 22 detects the light distribution 8 of the headlight 2 on the test surface 6 as such and together with the position marking projected onto the test surface 6. From the images of the light distribution 8 from the camera 22, the controller 21 can first determine the type of the headlight 2 and the operating state it is in. Depending on this, the position marking can be formed. The controller 21 can then ensure that with the laser scanner 23 or another laser scanner, not shown here, in addition to the position marking, for example with a different line shape or in a different color, auxiliary lines are projected onto the test surface 6, which for example a bright Display the dark limit of the light distribution 8 as determined by determining the maximum gradient of the light intensity of the light distribution 8 over the test area 6 from the images from the camera 22. With such an auxiliary line, the setting of a correct alignment of the respective headlight 2 with respect to the position marking on the test surface 6 can be simplified. In any case, ie with and without auxiliary lines, deviations from features of the light distribution 8 over the test area 6 with respect to the position marking can be quantitatively determined by the position marking on the test area depending on the position of the respective headlight 2 relative to the test area 6 Position is shifted into a position on the test surface 6, in which it is arranged according to the regulations in relation to the light distribution 8 above the test surface 6, and in that the corresponding displacements of the position marking are recorded quantitatively. The camera 22 can also be used to carry out area monitoring of the area in front of the laser scanner 13 in which the laser beam is not eye-safe despite its rapid swiveling. This eye safety is ensured with increasing distance from the laser scanner 13 by the rapid swiveling of the laser beam 15. A additional safety device can therefore be provided to switch off the laser 14 when both scanner mirrors 17 and 18 are at rest. It goes without saying that the vicinity of the laser scanner 13 can also be monitored for the occurrence of objects by sensors other than the camera 22. 1 also shows that the position detection devices 11 for detecting the headlight position of the headlight 2 to be adjusted in each case and the alignment devices 9 in the form of the chassis measuring stand 10 are connected to the controller 21 so that they control the headlight position of the headlight 2 and can take into account the alignment of the longitudinal center plane of the respective motor vehicle 3 when projecting the position marking onto the test surface 6. The controller 21 can also act on the respective motor vehicle 3 in order to set the respective headlight 2 by means of an adjustment tool (not shown here) or via the control of the motor vehicle 3, so that the light distribution 8 detected by the camera 22 on the test surface 6 corresponds to the respective front - gave. This can then be documented by a further image of the camera 22, which shows the light distribution 8 of the set headlight 2 together with the position marking.

3 shows, as an alternative to the camera 12 according to FIG. 2, a further laser scanner 23 as a component of the position detection devices 11. This further laser scanner 23 is provided for the laser beam 25 emitted by its laser 24 with the help of an operator controlled scanner 26 until the laser beam 25 strikes a reference point of the respective headlight 2. The position of this reference point or the headlight position of the headlight 2 can then be derived from the position of scanner mirrors 27 and 28 of the laser scanner 23.

Regardless of its embodiment, the position detection devices 11 and the laser scanner 13 and possibly the camera 22 can be combined in one unit, which is positioned between the respective motor vehicle 3 and the measuring wall 5. For the right and left headlights 2 of the respective motor vehicle 3, a separate unit can be arranged somewhat outside the lane of the motor vehicle 3.

FIG. 4 is a view of the test area 6 according to FIG. 1 with the position marking 29 projected thereon. The position marking 29 here comprises a dashed horizontal hyphen 30, a central mark 31 as the intersection of the hyphen 30 with a vertical dashed line

Line 32 and a light-dark boundary 33, which is shown with solid lines. The light The dark boundary 33 is matched to the type of the respective headlight 2 and indicates the course that the actual light-dark boundary 34 of its light distribution 8 shown as a dotted line should take on the test surface 6 when the headlight 2 is correctly adjusted. Here, the actual light-dark boundary 34 is offset upward and to the left relative to the light-dark boundary 33 of the position marker 29. These deviations are to be compensated for by adjusting the headlight 2.

In the embodiment of the measuring wall 5 of the device according to the invention shown in FIG. 5, four point sensors 35 to 38 are arranged in the test area 6, each of which is designed as a photo diode 39 and registers when the laser beam 15 of the laser scanner 13 according to FIG. 1 falls on it. The point sensors 35 to 38 are aids for calibrating the laser scanner 13. For this purpose, the vertical line 32 can be moved in a horizontal direction over the test surface 6 with the laser scanner 13. With the aid of the point sensors 35 and 38 arranged one above the other and 36 and 37 on the other hand, it can be determined whether the vertical line 32 runs exactly vertically in its area because it then sweeps over both point sensors 35 and 38 or 36 and 37 arranged one above the other. It is also possible to determine by how much the laser scanner 13 has to be adjusted in order to overcome the horizontal distance 41 between the point sensors 35 and 38 on the one hand and 36 and 37 on the other when projecting the vertical line 32. Correspondingly, when projecting a horizontal line 42 with the point sensors 35 and 36 on the one hand and 37 and 38 on the other hand, it can be checked whether the line 42 runs exactly horizontally and by how much the laser scanner 13 has to be adjusted by a vertical distance 40 between to overcome the point sensors 35 and 36 on the one hand and 37 and 38 on the other. While the point sensors 35 to 38 are shown in a square arrangement in FIG. 5, the horizontal distance 41 can deviate from the vertical distance 40, for example it can be larger. One of the four point sensors according to FIG. 5 can also be omitted, but then the exact horizontal or vertical course of the lines 42 and 32 can only be checked at one point on the test surface 6. If a check of the horizontal or vertical course of lines 42 and 32 is dispensed with, only two point sensors are sufficient, for example point sensors 35 and 37 or 36 and 38, which are both in vertical distance 40 and in horizontal distance 41 are arranged to each other, for calibrating the laser scanner 13. LIST OF REFERENCE NUMBERS

1 device

2 headlights

3 motor vehicle

4 bottom

5 measuring wall

6 test area

7 distance

8 light distribution

9 Alignment device

10 chassis measuring stand

1 1 Position detection devices

12 camera

13 laser scanners

14 lasers

15 laser beam

16 scanners

-18 scanner mirror

-20 swivel axis

21 control

22 camera

23 other laser scanners

24 more lasers

25 more laser beams

26 more scanners

-28 more scanner mirrors

29 Position marking

30 horizontal hyphen

31 central brand

32 vertical line

33 Light-dark boundary of the position marker 29

34 actual light-dark limit of light distribution 8-38 point sensor

39 photodiode

40 vertical distance

41 horizontal distance

42 horizontal line

Claims

PATENT CLAIMS

1 . Method for checking the setting of headlights (2) of motor vehicles (3) with

Aligning the respective motor vehicle (3) with respect to a test surface (6) arranged at a distance in front of the motor vehicle (3);

Setting a position of a position marker (29) on the test surface (6) as a function of a headlight position of the headlight (2) to be adjusted relative to the test surface (6);

Projecting a light distribution (8) with the headlight (2) to be adjusted in each case onto the test surface (6) and

Determining a relative position of the light distribution (8) on the test surface (6) with respect to the position marking (29),

characterized in that the position marker (29) is projected onto the test surface (6) with a laser scanner (13), the position of the position marker (29) on the test surface (6) being adjusted by actuating the laser scanner (13).

2. The method according to claim 1, characterized in that the headlight position of the respective headlight to be adjusted (2) relative to the test surface (6) while aligning a further laser beam (25) of a further laser scanner (23) to a reference point of the headlight (2) is determined.

3. The method according to claim 1 or 2, characterized in that a laser beam (15) of the laser scanner (13) is switched off when it is determined that a scanner (16) of the laser scanner (13) is at rest and / or that an object enters a monitoring area in front of the laser scanner (13).

4. The method according to any one of the preceding claims, characterized in that one or the laser beam (15) of the laser scanner (13) is formed from light with wavelengths in the range from 480 nm to 680 nm or from 500 nm to 600 nm.

5. The method according to any one of the preceding claims, characterized in that the position marker (29) comprises at least one line, the line having at least one kink or closed in a ring.

6. The method according to any one of the preceding claims, characterized in that the position marker (29) is formed as a function of a type and / or an operating state of the headlight (2) to be adjusted in each case, the type and / or the operating state of the respectively to be adjusted Headlamp (2) is optionally determined by taking a distribution image of the light distribution (8) on the test surface (6) and analyzing this distribution image.

7. The method according to any one of the preceding claims, characterized in that the relative position of the light distribution (8) on the test surface (6) relative to the position marker (29)

by moving the position marker (29) projected onto the test surface (6) with the laser scanner (13) until the light distribution (8) is aligned with the position marker (29) in accordance with a regulation, and detecting the necessary shifts with the Laser scanner (13) or position marker (29) projected onto the test surface (6)

by recording a superimposed marking and distribution image of the position marking (29) and the light distribution (8) on the test surface (6) and analyzing this marking and distribution image

be determined.

8. The method according to claim 7, characterized in that for calibrating a camera (22) for recording the superimposed marking and distribution image, the test surface (6) is provided with a known two-dimensional reference pattern and the reference pattern is registered with the camera (22).

9. The method according to any one of the preceding claims, characterized in that an orientation of a vehicle longitudinal median plane and / or a direction of travel of the respective motor vehicle (3) running at an angle of the driving axis relative to the test surface (6) is determined and / or adjusted and when adjusting the Position of the position marker (29) on the test surface (6) is taken into account.

10. The method according to any one of the preceding claims, characterized in that the headlight (2) to be adjusted in each case is adjusted depending on the determined relative position in order to align the light distribution (8) according to the or a regulation to the position marker (29).

1 1. Method according to one of the preceding claims, characterized in that for calibrating the laser scanner (13) with the laser scanner (13), a vertical line (32) and a horizontal line are successively projected onto the test surface (6) and over the test surface (6) in horizontal direction or vertical direction, whereby point sensors (35 to 38) arranged in the test surface (6) register when these are struck by the laser beam (15) of the laser scanner (13).

12. The method according to any one of claims 1 to 10, characterized in that for the calibration of the laser scanner (13) the test surface is provided with a known two-dimensional reference pattern and that with the laser scanner (13) a reference mark comprising a plurality of reference points on the test surface (6) is projected, a relative position of the reference points with respect to the reference pattern being registered.

13. The device (1) for performing the method according to one of the preceding claims

a measuring wall (5) having a test surface (6) and

a controller which is designed to set a position of a position marker (29) on the test surface (6);

characterized in that there is a laser scanner (13) which is designed to project the position marker (29) onto the test surface (6), the control being designed to determine the position of the position marker (29) on the test surface (6 ) by activating the laser scanner (13).

14. The device (1) according to claim 13, characterized in that position detection devices (11) are provided and are designed to detect a headlight position of the headlight (2) to be adjusted relative to the test surface (6) and that the control is designed for this purpose is to set the position of the position marker (29) on the test surface (6) depending on the detected headlight position of the headlight (2) to be adjusted relative to the test surface (6).

15. The device (1) according to claim 14, characterized in that the position detection devices (1 1) have a further laser scanner (23) and are designed to under the headlight position of the headlight to be adjusted relative to the test surface (6) Alignment of a further laser beam (25) of the further laser scanner (23) to determine a reference point of the headlight (2).

16. The device (1) according to one of claims 13 to 15, characterized in that safety devices are provided and are designed to switch off a laser beam (15) of the laser scanner (13) when the safety devices determine that a scanner (16) of the Laser scanner (13) is at rest and / or that an object enters a monitoring area in front of the laser scanner (13).

17. The device (1) according to any one of claims 13 to 16, characterized in that the laser scanner (13) has a laser (14) which has a laser beam (15) made of light with wavelengths in the range from 500 nm to 600 nm trains.

18. Device (1) according to one of claims 13 to 17, characterized in that an alignment and / or alignment detection device is arranged at a distance in front of the test surface (6) of the measuring wall (5) and for setting and / or determining an alignment of a Vehicle longitudinal center plane and / or a direction of travel of the respective motor vehicle (3) running at a driving axis angle relative to the test surface (6) is formed.

19. The device (1) according to claim 18, characterized in that the alignment and / or alignment detection device is a chassis measuring stand (10).

20. The device (1) according to any one of claims 13 to 19, characterized in that a headlamp detection device is provided, which is designed to detect a type and / or an operating state of the headlamp (2) to be adjusted in each case, and that the controller for this is designed to form the position marker (29) depending on the recognized type and / or operating state of the headlight (2) to be adjusted in each case.

21. Device (1) according to claim 20, characterized in that the headlight detection device has a camera (12) directed at the headlight (2) or a camera (12, 22) directed at the test surface (6) and is designed to do this Type and / or the operating state of the headlight (2) to be adjusted in each case by picking up a Determine the headlight image of the illuminating headlight (2) or a distribution image of the light distribution (8) of the illuminating headlight (2) on the test surface (6) with the camera (12, 22) and analyze this distribution image.

22. The device (1) according to one of claims 13 to 21, characterized in that relative position determining devices are present,

which comprise a displacement device for displacing the position marker (29) projected onto the test surface (6) with the laser scanner (13) in response to manual command inputs and are designed to shift the position marker (6) projected onto the test surface (6) with the laser scanner (13) 29) between a start position and an end position of the position marker (29) projected onto the test surface (6) with the laser scanner (13), or

which comprise the or a camera (12, 22) directed at the test surface (6) and are designed to position the light distribution (8) on the test surface (6) relative to the position marker (29) by recording a superimposed marker and determining the distribution image of the position marking (29) and the light distribution (8) on the test surface (6) and analyzing this marking and distribution image.

23. The device (1) according to one of claims 13 to 22, characterized in that adjusting devices are provided and are designed to adjust the headlights (2) to be adjusted in each case as a function of the determined relative position in order to distribute the light (8). to align according to the or a provision on the position marker (29).

24. The device (1) according to one of claims 13 to 23, characterized in that in the test area (6) of the measuring wall (5) point sensors (35 to 38) are arranged which register when they are from the laser beam (15) of the Laser scanners (13) are taken, the point sensors (35 to 38) being connected to the control and the control being designed to automatically calibrate the laser scanner (13) with the aid of the point sensors (35 to 38).

25. The device (1) according to claim 24, characterized in that two of the point sensors (35 to 38) at a vertical distance (40) one above the other and two of the point sensors (35 to 38) at a horizontal distance (41) side by side in the test surface (36) are arranged.