Adjusting the nominal light emission angle of a vehicle's headlight

Abstract

A method for adjusting the nominal light emission angle of a front headlight (2) of a vehicle (1) is described, comprising a camera system (9) and a device (28) for adjusting the nominal light emission angle of the front headlight (2).The procedure comprises the following steps: using the camera system (9) detecting (31) a surface (13, 36, 37, 38) located in front of the vehicle which has at least one predetermined feature; determining (32) the distance (d) of the surface (13, 36, 37, 38) to the vehicle (1); determining the orientation of the vehicle (1) with respect to the ground (12) and checking (33) whether at least one predetermined stability condition of the orientation of the vehicle (1) with respect to the ground (12) is satisfied; if at least one predefined stability condition of the vehicle's orientation (1) with respect to the ground (12) is met, the surface (13, 36, 37, 38) is illuminated by means of the headlight (2) and a light pattern (40) reflected by the surface (13, 36, 37, 38) of the headlight (2) is detected by means of the camera system (9); based on the detected light pattern (40) the nominal light emission angle of the headlight (2) is adjusted (35).

Description

The present invention relates to a method and a device for adjusting the nominal light emission angle of a vehicle's headlight. The invention further relates to a vehicle, a computer-implemented method, a computer program product, a computer-readable data carrier, and a data carrier signal. In light of current and upcoming legal requirements and with road safety in mind, the correct adjustment of vehicle headlights and reliable headlight range control are of particular importance. The beam range of a headlight can usually be adjusted or corrected manually and / or automatically, for example, using a stepper motor. Furthermore, so-called glare-free high beam systems (ADB) and headlights with camera-based dynamic headlight range control (CbADL) are also available. These camera-based systems require that both the camera and the headlight be calibrated under the same controlled conditions, meaning they are precisely aligned with the vehicle. This calibration is also referred to as "aiming."Joint calibration is necessary because installation and manufacturing tolerances are significantly larger than acceptable tolerances for headlight range adjustment. Headlight leveling, also known as "leveling," typically involves the following steps. First, the headlight's adjustment position is determined. This requires adjusting the zero angle. With the stepper motor angle nominally set, the headlight is calibrated as part of the assembly process to achieve a defined light output angle. Normally, at the end of the production line, the headlight (on the control side) is set to a "zero position." Because the headlights, as components, and their assembly within the overall vehicle system have significant mechanical tolerances, the angle is subsequently corrected using adjusting screws or electronic controls to ensure the light is emitted at a specific angle.This process, also known as "adjustment" or "aiming," establishes the set position as a prerequisite for any further compensation. The subsequent headlight range adjustment, also called "leveling," detects changes in the angle between the vehicle and the ground and compensates for the fixed light emission angle or the necessary deviation from the set position. The light emission direction of each headlight is subject to individual manufacturing tolerances, which can be several degrees and are due to the specific optics and the headlight's mounting within the vehicle. The "aiming" required at the end of the manufacturing process, in which the headlight's orientation is adjusted to the vehicle, is traditionally done using adjustment screws, but can also be done electronically. Electronic actuation using an electric motor, pixel adjustment, or simply detecting the deviation of the current setting from a nominal setting are also possible. If the headlight is correctly calibrated vertically, a dynamic headlamp leveling system can be used to maintain a constant beam angle relative to the ground, even if the vehicle's pitch angle changes. While this may not be 100% achievable or necessary under dynamic conditions, it is at least possible to compensate for load-related changes in the pitch angle. This compensation is traditionally performed relative to a nominal pitch angle. For example, if the vehicle's pitch angle increases by 1 degree from the nominal pitch angle, the beam angle is lowered by 1 degree from the nominal setting. Traditionally, each vehicle must be individually calibrated at the end of the manufacturing process, particularly due to manufacturing tolerances, individual equipment-related load, wheel suspension and damping conditions, as well as individual sensor installations. A sensor output signal, such as the output signal of a ride height sensor, must be determined for each vehicle, corresponding to the vehicle's nominal state. Load-related changes in the pitch angle can be determined, for example, using ride height sensors or via camera-based systems while driving. Existing systems effectively use two separate measurement mechanisms for calibration. The first system determines the vehicle's reference pitch curve at the end of production. In the case of ride height sensors, this means storing the raw output data; in the case of a camera, visually detectable patterns are used to determine the pixel position that points straight ahead relative to the vehicle. The second system individually adjusts the headlights so that their beam angle has a predetermined, i.e., defined, slope. In both cases, it is necessary that the sensor calibration and the headlight calibration are performed under the same vehicle conditions. Document DE 10 2019 207 838 A1 describes a method for aligning the light beams emitted by the headlights of a motor vehicle. Document US 10 953 787 B1 discloses a system and method for headlight leveling depending on the vehicle's load. Document US 10 894 503 B2 describes a continuous headlight range adjustment that replaces the two discrete high beam and low beam settings. Document US 2022 / 0 227 284 A1 describes a method for controlling the light emission direction of a vehicle's headlight, wherein an optimization pattern is projected in front of the vehicle using a headlight and image data of the optimization pattern is acquired using vehicle sensors. Against this background, it is an object of the present invention to provide an advantageous method for adjusting the nominal light emission angle of a vehicle's headlight. Further objects are to provide an advantageous device for adjusting the nominal light emission angle of a vehicle's headlight, a vehicle, a computer-implemented method, a computer program product, a computer-readable data carrier, and a data carrier signal. These problems are solved by a method for adjusting the nominal light emission angle of a vehicle headlight according to claim 1, a device for adjusting the nominal light emission angle of a vehicle headlight according to claim 12, a vehicle according to claim 13, a computer-implemented method according to claim 14, a computer program product according to claim 15, a computer-readable data carrier according to claim 16, and a data carrier signal according to claim 17. The dependent claims contain further advantageous embodiments of the invention. The inventive method for adjusting, in other words, calibrating or controlling in the sense of "aiming," the nominal light emission angle, i.e., the setting or output light emission angle, of a vehicle's headlight relates to a vehicle comprising a camera system, preferably with a front camera, and a device for adjusting the nominal light emission angle of the headlight. The method comprises the following steps: Using the camera system, in particular a front camera, a surface located in front of the vehicle is detected, which has at least one predetermined feature, e.g., a defined, predetermined, or fixed feature. In a further step, the distance of the surface to the vehicle, e.g., the distance of the surface from, or in other words, to, the headlight, is determined. In a further step, the vehicle's orientation relative to the ground, i.e., the surface or roadway, is determined, and it is checked whether at least one predefined stability condition for the vehicle's orientation relative to the ground is met. If the at least one predefined stability condition for the vehicle's orientation relative to the ground is met, the surface is illuminated by the headlight, and the light pattern reflected by the headlight from the surface is captured by the camera system. The surface can, of course, also be illuminated by the headlight outside of the inventive method, i.e., even if the predefined stability condition is not met.However, illuminating and capturing the reflected light pattern for the purpose of further evaluation within the framework of the inventive method only makes sense if the specified stability condition is met. A stability condition for the vehicle's orientation relative to the ground is understood to be at least one condition for at least one characteristic of the vehicle's current operating state, which ensures that the vehicle and the ground remain in a defined, preferably at least nearly constant, geometric or spatial orientation or relationship to each other for a specific period of time. For example, the condition may include that the pitch angle change and / or the yaw angle change of the vehicle relative to the ground each remain below a predetermined threshold value. In a further step, the nominal beam angle of the headlight is adjusted based on the detected light pattern. This adjustment can be carried out using the headlight beam angle adjustment device. In connection with the present invention, the vehicle can be, for example, a motor vehicle or a rail vehicle. The terms "adjusting" or "controlling" are understood to mean both control and regulation. A front camera is understood to be a camera designed to capture images in the forward direction of the vehicle or in the direction of travel. The aforementioned device for adjusting the light emission angle of the headlight can, for example, include a stepper motor. In an advantageous embodiment, the vehicle performs a translational movement during the execution of the method. In other words, the vehicle moves or travels while the method according to the invention is carried out. The method can, for example, be automated and / or performed while driving. It is also advantageous if, during the procedure, the headlight beam is adjusted by the vehicle itself to optimize the recognition of the light pattern, e.g., by changing the intensity, pulsing the headlight, or shaking the headlight. These measures can be designed so that they are imperceptible to a driver or user and therefore do not cause any disturbance. Alternatively, the system should recognize that it is only using its own light pattern. The present invention has the overall advantage of enabling the calibration, or "aiming," of a headlight—in other words, the adjustment of its nominal beam angle—under dynamic environmental conditions without requiring any action from the user or driver. The vehicle does not need to be stationary to adjust the nominal beam angle of its headlight; the calibration or adjustment can be performed while driving. Many driving situations typically arise in which the necessary conditions for headlight calibration are present, allowing the calibration to be performed more frequently and reliably than with prior art methods. This improves overall road safety.In some cases, it may be possible to forgo factory calibration or service calibration and perform it during the operation of the vehicle. In a preferred embodiment, with respect to at least one predefined feature of the surface located in front of the vehicle, it is determined or checked whether the detected surface in front of the vehicle exhibits predefined reflective properties and / or predefined properties regarding homogeneity and / or uniformity, and / or has an orientation relative to the vehicle that lies within a predefined range. It is advantageous if the detected surface lies in a plane that extends substantially perpendicular to the longitudinal axis of the vehicle. The reflective properties of the surface can depend, among other things, on the current ambient lighting.The at least one specified characteristic of the surface in front of the vehicle may include that the surface is light-reflecting and / or that the surface is a single color and / or that the surface is homogeneous, in other words having few patterns or structures that could cause irritation. Optionally, it can be determined or checked whether the detected surface in front of the vehicle has at least one predefined feature, in particular a defined, predetermined, or specified feature, whereby at least one plausibility check can be performed. Using a plausibility check can simplify the detection of a suitable surface located in front of the vehicle. In another variant, at least one predefined road surface characteristic can be taken into account. GPS data or comparable data, or road types, can also be included. For example, a measurement is more advantageous on a motorway than in a winding stretch of forest. Preferably, the distance between the surface and the vehicle, in particular the distance between the surface and the headlight, is determined using a radar sensor and / or an ultrasonic sensor and / or a lidar sensor and / or a camera, e.g., a camera from the aforementioned camera system. The use of radar systems has the advantage that these measurements can be performed with very high accuracy. For short distances, the accuracy can be further improved by fusing multiple sensors. The vehicle's orientation relative to the ground can be determined using a pitch sensor and / or a yaw sensor. As part of the test to determine whether at least one predefined stability condition regarding the vehicle's alignment with the ground is met, the vehicle's speed and / or acceleration can be recorded. The recorded speed and / or acceleration can then be compared with predefined limits. Additionally or alternatively, as part of the test to determine whether at least one predefined stability condition regarding the vehicle's alignment with the ground is met, at least one road surface characteristic can be recorded. In other words, it can be taken into account whether the vehicle is traveling on a highway or a winding country road. GPS data can be used to determine the type of road surface or road.At least one characteristic of the road surface can be recorded as a feature of the roadway; in other words, whether the road has cobblestones, asphalt, gravel, etc. The measurement can either be conditional on the roadway exhibiting corresponding predefined characteristics, or a measurement can be subsequently discarded if, for example, it turns out that it was taken on a winding road or on cobblestones. The specified stability condition may, for example, require that the reflected light pattern of the headlight is captured or detected for a specified period of time, i.e., that it is detectable for the entire duration, particularly with a change in the position of the captured light pattern of the headlight that is less than a specified limit value. Preferably, throughout the entire execution of the procedure, it is monitored whether at least one predetermined stability condition of the vehicle's orientation with respect to the ground is met. In another variant, the camera system can sequentially capture multiple images of the light pattern reflected from the surface of the headlight. The captured images can then be compared and analyzed. For example, sequentially captured images can be compared, and only consecutively captured images—in other words, image sequences—that meet at least one predefined conformity condition can be used as the basis for adjusting the nominal light emission angle of the headlight. For instance, it can be required that the position of at least one feature characterizing the light pattern deviates by less than a defined threshold in the considered images, meaning that the feature appears in essentially the same position in the images. In one exemplary variant, the procedure can include the following further steps: In an optional first step, based on at least one image captured by a front camera of the camera system (i.e., image-based), a geometric relationship is determined, e.g., calculated, between the output light emission direction of the headlight and a direction defining the current orientation, in particular the vertical and / or horizontal orientation, of the front camera. This direction defining the current orientation of the front camera can be an optical axis of the camera or a central image capture direction. In an optional second step, the current pitch angle of the front camera, e.g., in relation to the direction defining the camera's orientation above the ground, and / or the current yaw angle of the front camera relative to a longitudinal axis of the vehicle are determined based on images captured by the front camera during a journey, i.e., during a translational movement of the vehicle—in other words, image-based. In an optional third step, control is performed, e.g.,...Adjusting and / or regulating the nominal light emission angle, in particular the vertical and / or horizontal nominal light emission angle, of the headlight based on the determined geometric relationship between the output light emission direction of the headlight and the direction defining the current orientation of the front camera and based on the determined current pitch angle of the front camera and / or based on the determined current yaw angle of the front camera. The method according to the invention and the described variants of the method according to the invention have the following advantages: Compared to the calibration methods and calibration systems known from the prior art, which are expensive and complex both during the manufacture of a vehicle and during its operation and maintenance, require installation space, and necessitate trained personnel, special measuring instruments, and a special calibration stand or corresponding setup for their application, the present invention offers a simple, cost-effective, reliable, and robust variant that can be used flexibly without a special setup or specialist personnel. Furthermore, by calibrating the camera and headlights together only in relation to each other and not individually in relation to the vehicle, the accumulation of errors can be avoided. This improves the precision and reliability of the control of the respective nominal light emission angle.Additionally, the lamp adjustment service can also be performed outside of workshops using the present invention. This eliminates the need to adapt workshop equipment for a lamp adjustment service. Furthermore, the overall calibration process is simplified because both the front camera and the respective headlight can be aligned with a higher tolerance relative to the vehicle. This means that these two calibration steps—the calibration of the front camera and the calibration of the headlight—can be performed with less effort than previously required. In particular, precise, fixed zero positions no longer need to be set at the end of the manufacturing process.Instead, according to the invention, it is possible to calibrate the light emission angle of a headlight with respect to the ground (i.e., in the vertical direction) or in the horizontal direction by determining a geometric relationship between the camera's orientation and the headlight's headlight. This can be achieved, for example, by using only a captured image of the projection of the headlight's light cone onto a surface, such as a screen or wall, at a known distance from the camera and headlight. During driving, the angle between the uncalibrated central image capture direction or optical axis of the front camera and the ground or the horizon can then be determined image-based.With this information alone, a misalignment of the headlight's beam angle relative to the ground can be determined, allowing for the calculation of a corresponding correction factor. Another advantage is that recalibration can be performed in the field at any time, particularly while driving, without requiring the vehicle to be unloaded. In contrast, current state-of-the-art recalibration requires the vehicle to be unloaded and that the same conditions prevail for servicing the vehicle pitch angle sensor system as were used for calibrating the headlights. Alternatively, both the sensor system and the headlights must be calibrated as part of the same repair. This requires that the person performing the repair has access to both systems and is trained accordingly. This is generally only the case at a workshop that also replaces ride height sensors.However, recalibration of a camera-based system is often only necessary as part of a windshield replacement, which can also be carried out outside of a specialized workshop. In contrast, the present invention enables calibration of the camera as part of a system for determining the pitch angle and the nominal light emission direction or the nominal beam range of the headlights without necessarily requiring a workshop. In a preferred embodiment, the geometric relationship between the initial light emission direction of the headlight and the direction defining the current orientation of the front camera can be determined by means of an image of the emitted light captured by the front camera, e.g., a projection of the headlight's light pattern onto a surface as described above, such as a projection surface. The projection surface can be a screen, e.g., a monitor or sign, or a wall, e.g., a canvas, a building facade, or similar. Advantageously, the distance of the projection surface from the front camera can be determined. This distance can be known, predetermined, fixed, measured, or determined. Furthermore, the angle between the direction defining the orientation of the front camera (e.g., a center line or axis of the image capture direction, or a horizontal or vertical line) and a boundary line (e.g., a horizontal or vertical boundary line) of the emitted light at the surface or projection area can be determined using the image of the emitted light from the headlight captured by the front camera. The angle can be determined directly from the position of the boundary line in the captured image. For example, the pixel position in the image can correspond to or be equivalent to the angle relative to the reference line (i.e., a direction defining the camera's orientation). Preferably, a correction angle for the light emission angle of the headlight is calculated, using the horizontal distance (dx) and the vertical distance (dy) of the headlight from the front camera and the distance of the headlight or the front camera to a projection surface. A specific example of this is explained in more detail below in the exemplary embodiments. In another variant, the vertical nominal light emission angle of the front headlight can be controlled, e.g., adjusted, in relation to a camera-based determined current horizon line or horizon plane. In another variant, the horizontal nominal light emission angle of the headlight can be controlled, e.g. adjusted, with respect to a camera-based determined current vertical reference line or reference plane, e.g. a longitudinal axis or a vertical longitudinal plane of the vehicle. The current pitch angle and / or yaw angle can be determined using the front camera. This has the advantage that no further or additional sensors are required. The device according to the invention for adjusting, in particular calibrating or controlling in the sense of "aiming", the nominal light emission angle of a vehicle's headlight, which comprises a camera system, preferably a front camera, and a device for adjusting the nominal light emission angle of the headlight, is designed for receiving and evaluating images captured by the camera system and for carrying out a previously described method according to the invention. The device according to the invention has the features and advantages already described above. Optionally, the device according to the invention is designed for receiving and evaluating data from vehicle-internal sensors, such as distance data and / or data on the vehicle's orientation relative to the ground. The vehicle according to the invention comprises a camera system, a device for adjusting the nominal light emission angle of the headlight, and a previously described device according to the invention for adjusting, e.g., controlling or calibrating, the nominal light emission angle of the headlight, or is designed to carry out a method according to the invention described above. The vehicle according to the invention has the advantages already described. The vehicle can be a motor vehicle or a rail vehicle. The motor vehicle can be a passenger car, a truck, a bus, a minibus, a motorcycle, or a moped. The computer-implemented method according to the invention comprises instructions that, when the program is executed by a computer, cause it to execute a method according to the invention as described above. The computer program product according to the invention comprises instructions that, when the program is executed by a computer, cause it to execute a method according to the invention as described above. The computer program product according to the invention is stored on the computer-readable data carrier according to the invention. The data carrier signal according to the invention transmits the computer program product according to the invention. The computer-implemented method according to the invention, the computer program product according to the invention, the computer-readable data carrier according to the invention, and the data carrier signal according to the invention have the features and advantages already mentioned above. The invention is explained in more detail below with reference to exemplary embodiments and the accompanying figures. Although the invention is illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. The figures are not necessarily detailed or to scale and may be enlarged or reduced to provide a better overview. Therefore, the functional details disclosed here are not to be understood as limiting, but merely as an illustrative basis to guide those skilled in this field of technology in using the present invention in a variety of ways. The expression "and / or" used here, when used in a series of two or more elements, means that each of the listed elements can be used alone, or any combination of two or more of the listed elements can be used. For example, when describing a composition containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. Fig. 1 schematically shows a vehicle and the calibration (aiming) of the nominal beam angle of a headlight. Fig. 2 schematically shows a method according to the invention in the form of a flowchart. Fig. 3 schematically shows a photographic pattern of the emitted light from a vehicle headlight projected onto an interior wall of a garage.Figure 4 schematically shows a photograph of the light emitted from a vehicle's headlight onto a house wall. Figure 5 schematically shows a photograph of the light emitted from a vehicle's headlight onto the rear of a vehicle ahead. Figure 6 schematically shows a vehicle and a photograph of the light emitted from the vehicle's headlight onto a house wall. Figure 7 schematically shows a vehicle and a photograph of the light emitted from the vehicle's headlight onto the rear of a vehicle ahead. Figure 8 schematically shows a vehicle and photographs of the light emitted from the vehicle's headlight onto the rear of a vehicle ahead at various times. Figure 9 schematically shows, to illustrate a first further step of a method according to the invention, a vehicle which projects a photograph onto a house wall by means of its headlight.Figure 10 schematically illustrates a second further step of a method according to the invention, showing a vehicle which projects an image of its headlight beam onto a house wall. Figure 11 schematically illustrates a third further step of a method according to the invention, showing a vehicle which projects an image of its headlight beam onto a house wall. Figure 12 schematically shows a projection of an image of a vehicle's headlight beam onto a house wall. Figure 13 schematically shows a vehicle and an oncoming vehicle in a top view. Figure 14 schematically shows a vehicle according to the invention with a control device according to the invention. Figure 1 schematically shows a vehicle 1, e.g., a motor vehicle. The vehicle 1 includes a headlight 2. The light emitted by the headlight 2 has a slope that determines or is influenced by the angle of emission. The upper edge of the light cone 3 in the vertical direction is used as the reference point. Before calibration (aiming), or in other words, before adjusting the nominal angle of emission, different vehicles 1 typically exhibit different angles of emission, or different slopes of the emitted light 3, relative to the ground 12 or a flat road surface. For various vehicles 1 before calibration, exemplary slopes are indicated by lines with reference numerals 4. The desired nominal slope is indicated by a dash-dot line with reference numerals 5.Vehicle headlights are typically calibrated to the nominal light emission angle or gradient 5 after the manufacturing process. This can be done electronically or using adjusting screws. During calibration, the vehicle 1 is usually unloaded. Figure 2 schematically shows a method 30 according to the invention in the form of a flowchart. In step 31, a surface located in front of the vehicle, which has at least one predetermined feature, e.g., a minimum reflectivity and / or a predetermined orientation, is detected using the vehicle's camera system, in particular a front camera. In a preferred embodiment, it is determined or checked whether the detected surface in front of the vehicle has predetermined reflective properties and / or an orientation or alignment with respect to the vehicle that lies within a predetermined range. It is advantageous if the detected surface lies in a plane that extends substantially perpendicular to the longitudinal axis of the vehicle 1. In step 32, which can also be performed before or simultaneously with step 31, the distance between the surface and the vehicle is determined. This is done, for example, using a radar sensor and / or an ultrasonic sensor and / or a camera, such as one from the aforementioned camera system. In step 33, the orientation of vehicle 1 with respect to ground 12 is determined, and it is checked whether at least one predefined stability condition of the orientation of vehicle 1 with respect to ground 12 is met. The stability condition may, for example, require that the reflected light pattern of the headlight is captured or detected for a predefined period of time and that the change in position of the captured light pattern is less than a predefined limit. If at least one predefined stability condition for the orientation of vehicle 1 with respect to ground 12 is not met, the procedure reverts or terminates. If at least one predefined stability condition for the orientation of vehicle 1 with respect to ground 12 is met, in step 34 the surface is illuminated by the headlight 2 and a light pattern or image of the headlight 2 reflected by the surface is captured by the camera system. Based on the captured light pattern or image, the nominal beam angle of the headlight 2 is adjusted or set in step 35. Figures 3, 4 to 5 show examples of surfaces that are fundamentally suitable for carrying out the method according to the invention. Figure 3 shows a captured image 14 of a view into a garage, looking at a rear wall of garage 36, where a photograph 40 of the emitted light from a headlight 2 of a vehicle 1 is captured on an interior wall, in this case the rear wall, of the garage and can be used to carry out a method according to the invention. Figure 4 schematically shows a house wall 37 illuminated by a headlight 2. The captured image 14 shows a photographic image or light pattern 40 of the emitted light, which can be used to carry out a method according to the invention. For the detection of static surfaces, as shown, for example, in Figures 3 and 4, position data such as GPS data (GPS - Global Positioning System) or comparable data can also be used, for example, to verify a static surface and / or to determine the orientation of the surface in relation to the vehicle 1. Figure 5 schematically shows a captured image 15 with a photographic image 40 of the emitted light from a headlight 2 of a vehicle 1 on the rear or back wall of a preceding vehicle 38, e.g., a truck. To detect or capture a dynamic, i.e., moving, surface, additional vehicle sensors can be used to improve the accuracy of the detection. In particular, sensors and / or data from driver assistance systems, e.g., lane detection from a lane keeping assist system and / or distance detection and / or road path detection, can be used. Furthermore, GPS data or comparable data from other systems can be used to predict the upcoming road course. In addition, specific ADAS (Advanced Driver Assistance Systems) features or ADAS applications can be used to improve the reliability of the method according to the invention. For example,This information is detected and taken into account when adaptive cruise control (ACC) or a motorway mode is activated, or when it has been detected that the vehicle is driving on a motorway or expressway. Figure 6 schematically shows a vehicle 1 and a photographic image 40 of the emitted light from the headlight 2 of the vehicle 1 projected onto a house wall 37. Figure 6 illustrates, by way of example, steps 31 and 32 for a static variant of a method according to the invention. In this variant, the vehicle 1 is parked in front of the house wall 37 to adjust the nominal light emission angle of the headlight 2. The distance d of the vehicle 1 to the house wall 37 is determined, e.g., by measurement. This can be done using sensors inside the vehicle, for example, by means of a camera system and / or a radar sensor. Alternatively or additionally, the distance d can be measured manually, e.g., by a user of the vehicle. If, during step 31, it is detected that the vehicle 1 is not aligned in a specified manner with respect to the house wall 37, which can in turn be determined by means of distance sensors, the vehicle can align itself correctly or information can be issued to the user, e.g. with the request to adjust the alignment of the vehicle. Figure 7 schematically shows a vehicle 1 and a photographic image 40 of the emitted light from the front headlight 2 of vehicle 1 projected onto the rear surface 38 of a preceding vehicle, which could be, for example, a truck, a trailer, a motorhome, or a van. In the case of dynamic variants of the method according to the invention, as shown, for example, in Figures 7 and 8, existing information from other ADAS functions, such as ACC, can be used to determine the distance between the vehicle 1 and the surface 38 used, i.e., the rear or back wall 38 of a preceding vehicle.For example, images of the light pattern 40 of the headlight 2, captured by a front camera under stable conditions with respect to the orientation and distance between vehicle 1 and surface 38, can be stored, and the distance between vehicle 1 and surface 38 can be calculated using these images. In this case, the nominal light emission angle of the headlight 2 can be adjusted iteratively based on the reliability of the current driving situation. As schematically illustrated in Fig. 7, the orientation of vehicle 1 and surface 38 relative to each other does not need to be permanently stable. In the example shown, at times t1 and t2, it was recorded, e.g., using appropriate sensors, that the pitch angle and yaw angle of vehicle 1 were stable and that the same distance existed between vehicle 1 and surface 38 at both times. At time t3, however, there was a large change in the yaw angle, which is why the images acquired at this time are not considered. At time t4, the pitch angle and yaw angle of vehicle 1 were stable again, i.e., they had not changed or had changed below a predefined threshold, so the images acquired at this time can be considered. Adjusting the nominal light emission angle of the headlight 2 can be performed in several steps. For example, at least one stability characteristic, e.g., a stability factor, can be determined simultaneously with camera-based image acquisition, e.g., calculated. Based on this at least one stability characteristic, an image area 41 (see Fig. 8) can be selected in the acquired images, which is suitable as a reference for adjusting the nominal light emission angle of the headlight 2. Fig. 8 illustrates this. Fig. 8 schematically shows a vehicle and photographs of the emitted light from the headlight 2 of vehicle 1 projected onto the rear side 38 of a preceding vehicle at various times t1, tn, and t4. The direction of travel is indicated by an arrow with the reference numeral 6. A characteristic feature of each captured photograph 40 of the emitted light from the headlight 2, in this case a kink at the upper edge of the photograph, is marked in each photograph 40 with a circle bearing the reference numeral 21 for orientation and as a reference feature. At time t1, in the example shown, five previously acquired photographic images 40 are evaluated, and an area 41 of the surface 38 is determined where the reference feature 21 is expected to be located. The position of area 41 depends on the dynamics of the vehicle 1 and the vehicle ahead, as well as on the initial setting of the headlight 2. In the image shown for t1 (see Figure 14 below t1 in Fig. 8), the respective reference feature 21 is located in the calculated area 41 in three out of five acquired photographic images 40. Until a later time tn, the calculation of the area 41 in which the reference feature 21 is expected to be located has continued. During this time, area 41 has become smaller and more reliable compared to time t1, since the vehicle dynamics have been monitored and evaluated over a longer period. Of a large number of photographs, 40 are shown in the example (see image 14 below tn in Fig. 14).8) only in one photograph the reference feature 21 outside the area 41. At time t4, based on the data and calculations available at time tn, including the determined distance of the vehicle 1 to the surface 38, an automated adjustment or setting of the nominal light emission angle of the headlight 2 is performed. In the example shown, the nominal light emission angle of the headlight 2 is corrected downwards, and then it is checked whether this new setting is correct or whether further calibration is necessary. This is indicated by an arrow 42. In the images on the far right of Fig. 8, the light pattern of the emitted light of the headlight 2 before the adjustment or adaptation according to the invention is marked with reference numeral 43, and after the adjustment or adaptation according to the invention with reference numeral 44. Optional further steps of a method according to the invention for adjusting the vertical nominal light emission angle of a headlight 2 of a vehicle 1 are explained below with reference to Figures 9, 10 to 11. Figures 9, 10 to 11 each show a vehicle 1 whose headlight 2 projects or emits light onto a wall 13 shown in a perspective view. The vehicle 1 comprises at least one headlight 2, a front camera 9, and a device (not explicitly shown) for adjusting the nominal light emission angle of the headlight 2. The field of view of the front camera 9, which is also referred to simply as the camera in the following, is characterized by an angle 10. The optical axis or central axis or mean image acquisition direction of the front camera 9 is characterized by a line with the reference numeral 11.Similar to the alignment of the headlights, the exact alignment of the camera's optical axis is subject to tolerances and varies from vehicle to vehicle. Light is projected from the headlight 2 onto a wall 13 arranged vertically to the ground 12. In this example, the wall 13 is a house wall. Alternatively, any projection surface can be used, for example, a screen or a canvas, or the rear of a vehicle traveling ahead. The front camera 9 captures the light projection from the headlight 2 onto the wall 13. The image 14 captured by the front camera 9 is shown on the far right in Figures 9, 10 to 11. In a further first step shown in Fig. 9, a geometric relationship between an output light emission direction 7 of the front headlight 2 and a direction defining the current orientation of the front camera 9, in this case direction 11, is determined, e.g., calculated, based on at least one image 14 captured by the front camera 9. The distance dCW between the wall 13 and the front camera 9 is assumed to be known or is measured. In the captured image 14, the distance hα between the vertically upper boundary line 16 of the image 3 and the vertical position 17 of the center line or optical axis 11 of the front camera 9 is determined with respect to a vertical axis 15. The distance hα corresponds to the angle α between the center axis 11 and the detection direction 18 of the vertically upper edge 16 of the image 3. Neither the exact detection direction or orientation of the front camera 9 nor the exact beam angle of the headlight 2 are known with regard to their orientation relative to the vehicle body, as no calibration has yet been performed. Both the front camera 9 and the headlight 2 are simply aligned as they were installed and generally deviate from their ideal alignment with respect to the vehicle 1 by a few degrees. In a step shown in Fig. 10, the current pitch angle of the front camera 9 relative to the ground 12, i.e., the angle β between the vertical position 17 of the central axis 11 and the ground 12, is determined, in particular calculated, based on images captured by the front camera 9 during a translational movement, i.e., during a journey of the vehicle 1. In other words, image-based. In this context, a mean horizon position can be determined image-based in a manner known from the prior art. The mean vertical position of the horizon line, which is shown as line 19 on the wall 13 or in the captured image 14 for illustration, correlates with the load-dependent pitch angle of the vehicle 1. The mean horizon line 19 is usually determined from a series of images captured successively during a journey of the vehicle. In the image 14 shown, the horizon line 19 is equivalent to the pixels that point "straight ahead," i.e., those parallel to the ground 12 captured image points. The angle β corresponds to the distance hβ in the vertical direction 15 between the vertical position of the central axis 11 of the front camera 9 and the horizon line 19. In contrast to prior art methods, no deviation of the current horizon line 19 from a starting horizon line is determined or used here. Instead, only the current horizon line or its position is required. In a third further step, based on the determined geometric relationship between the initial light emission direction 7 of the headlight 2 and the direction 11 defining the current orientation of the front camera 9 (i.e., angle α), and based on the determined current pitch angle β of the front camera 9, the vertical nominal light emission angle of the headlight 2 (i.e., the light emission angle relative to the ground 12) is controlled, i.e., adjusted. This is shown schematically in Fig. 11. An angular deviation γ of the uncalibrated initial beam angle 7 from a horizontal direction 20 is determined. The distance hγ, which correlates with the angle γ, can then be determined and used based on the image. Using this angle γ, a nominal light emission angle with respect to the ground 12 can be controlled, whereby the angle γ can be compensated by adding it to the desired inclination angle or the desired slope. The vertical distance hCH between the headlight 2 and the front camera 9, the horizontal distance dCH between the headlight 2 and the front camera 9, and the horizontal distance dHW between the headlight 2 and the wall 13 can be assumed to be known, or measured or calculated. Using these values, the angle γ can be calculated according to the following equation. The angle γ then serves as the basis for controlling the vertical nominal light emission angle of the headlight 2. In addition to the example described, images can also be captured and evaluated from several different distances to the projection screen 13. This can improve the accuracy of the described method. Analogous to the previously described method, vertical control, in particular calibration (aiming), of the light emission angle of the headlight 2 can also be performed using the front camera 9 without the need for precise initial calibration at the end of a manufacturing process. In this case, a camera-based vertical reference line, analogous to the horizon line 19, can be determined to establish the yaw angle of the front camera 9. For this purpose, a multiple of consecutively recorded images captured during a journey of the vehicle 1 can be evaluated to determine a center line or reference line that runs perpendicular or vertically in all images. Furthermore, analogous to the method described with reference to Figs. 9, 10 to 11, a geometric relationship can be determined between a central axis 11 of the front camera 9 and its horizontal position relative to a feature of the light image 3 projected onto a wall 13 that characterizes the horizontal direction of emission of the front headlight 2. An exemplary projection is shown in Fig. 12. Here, a kink 21 is visible as a suitable reference feature, which can be used analogously to the vertical boundary line 16 for horizontal calibration. Figure 13 schematically shows a vehicle 1 and an oncoming vehicle 22 in a top view. The vehicle 1 includes a front camera 9 and at least one headlight 2. The front camera 9 is initially not calibrated or adjusted with respect to its central axis or central image capture direction 11, i.e., its orientation relative to a longitudinal axis of the vehicle. This is indicated by arrows 26. The beam direction or light emission direction of the headlight 2 can be controlled horizontally by means of a suitable device. This is indicated by arrow 27. At the end of a manufacturing process, various vehicles 1 can exhibit the light emission directions of the headlight 2, which are exemplified by reference numeral 24. The nominal light emission direction 25 is the target. A corresponding control in the form of a calibration can be carried out according to an analogous procedure to the procedure already described with reference to Figs. 9, 10 to 11, using the kink 21 shown in Fig. 12 as a reference feature. In this context, for example in the case of an LED headlight, the emission intensity of individual pixels of a headlight 2 can be controlled. This is indicated by the reference numeral 23, which illustrates the light cones of individual pixel rows. For example, with individually controllable LED light sources of the headlight 2, individual pixels within a pixel matrix can be individually controlled with respect to their intensity and / or emission direction in order to achieve the desired nominal emission direction. A vehicle 1 according to the invention, which may be, for example, a vehicle 1 as shown in Figures 1, 6 to 11 and 13, is shown schematically in Figure 14. It comprises a control device 28, not explicitly shown in the other figures, for adjusting the nominal light emission angle of a headlight 2. The control device 28 is designed to receive 29 and evaluate images captured by means of the front camera 9 and to execute a method for adjusting the nominal light emission angle of the headlight 2, as described by way of example in Figures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 to 13. Reference symbol list: 1 Vehicle 2 Headlights 3 Light cone, light pattern 4 Gradients of the emitted light of various vehicles before calibration of the light emission angle 5 Nominal gradient 6 Direction of travel 7 Actual gradients of the emitted light 9 Front camera 10 Field of view of the front camera 11 Central axis / mean image capture direction of the front camera 12 Ground 13 Wall / projection surface 14 Captured image 15 Vertical axis 16 Vertical upper edge of the light pattern 17 Vertical position of the projection of the central axis of the front camera 18 Capture direction of the vertical upper edge of the light pattern 19 Mean vertical position of the horizon line 20 Horizontal direction 21 Bend,Reference feature 22 Vehicle 23 Beam cone of individual pixel rows 24 Beam directions 25 Nominal beam direction 26 Orientation control of the front camera with respect to a longitudinal axis of the vehicle 27 Horizontal nominal light emission angle control of the headlight 28 Device for adjusting the nominal light emission angle of the headlight 29 Data and / or signal transmission 30 Method 31 Detection of a surface located in front of the vehicle which has at least one predefined feature 32 Determining the distance of the surface to the vehicle 33 Determining the orientation of the vehicle with respect to the ground and checking,whether at least one predefined stability condition of the vehicle's orientation with respect to the ground is met 34 Illuminating the surface with the headlight and capturing a light pattern reflected by the surface from the headlight using the camera system 35 Adjusting the nominal light emission angle of the headlight based on the captured light pattern 36 Garage / rear wall 37 House wall, surface 38 Rear wall / back of a vehicle,Surface 40 Light pattern / Light pattern 41 Area of ​​the surface 42 Adjustment direction of the nominal light emission angle 43 Light pattern before adjustment 44 Light pattern after adjustment J yes N no α Angle β Angle γ Angle hαvertical distance hβvertical distance hγvertical distance d Distance of surface / wall to vehicle dChorizontal distance between wall and front camera hCHvertical distance between headlight and front camera dCHhorizontal distance between headlight and front camera dHhorizontal distance between headlight and wall t1-t4 Time points tn Time point, QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2019 207 838 A1

[0008] US 10 953 787 B1

[0008] US 10 894 503 B2

[0008] US 2022 / 0 227 284 A1

[0008]

Claims

A method for adjusting the nominal light emission angle of a headlight (2) of a vehicle (1), comprising a camera system (9) and a device (28) for adjusting the nominal light emission angle of the headlight (2), characterized in that the method comprises the following steps: - using the camera system (9) detecting (31) a surface (13, 36, 37, 38) located in front of the vehicle, which has at least one predetermined feature, - determining (32) the distance (d) of the surface (13, 36, 37, 38) to the vehicle (1), - determining the orientation of the vehicle (1) with respect to the ground (12) and checking (33) whether at least one predetermined stability condition of the orientation of the vehicle (1) with respect to the ground (12) is satisfied, - if the at least one predetermined stability condition of the orientation of the vehicle (1) with respect to the ground (12) is satisfied, illuminating the Surface (13, 36, 37,38) by means of the headlight (2) and detection (34) of a light pattern (40) reflected by the surface (13, 36, 37, 38) of the headlight (2) by means of the camera system (9), - based on the detected light pattern (40) adjusting (35) the nominal light emission angle of the headlight (2)., Method according to claim 1, characterized in that the vehicle (1) performs a translational movement (6) during the execution of the method. Method according to claim 1 or 2, characterized in that it is determined whether the detected surface (13, 36, 37, 38) in front of the vehicle (1) has predetermined reflective properties and / or predetermined properties with respect to homogeneity and / or color consistency and / or has an orientation in a predetermined area with respect to the vehicle (1). Method according to one of claims 1 to 3, characterized in that it is determined whether the detected surface (13, 36, 37, 38) has at least one predetermined feature relating to the vehicle (1), wherein at least one plausibility check is carried out. Method according to one of claims 1 to 4, characterized in that the distance (d) of the surface (13, 36, 37, 38) to the vehicle (1) is determined by means of a radar sensor and / or an ultrasonic sensor and / or a lidar sensor and / or a camera (9). Method according to one of claims 1 to 5, characterized in that the orientation of the vehicle (1) with respect to the ground (12) is determined by means of a pitch angle sensor and / or a yaw angle sensor. Method according to one of claims 1 to 6, characterized in that, as part of the test to determine whether at least one predetermined stability condition of the orientation of the vehicle (1) in relation to the ground (12) is met, the speed and / or the acceleration of the vehicle (1) and / or at least one feature of the roadway is recorded. Method according to one of claims 1 to 7, characterized in that during the entire time of carrying out the method, it is monitored whether the at least one predetermined stability condition of the orientation of the vehicle (1) with respect to the ground (12) is fulfilled. Method according to one of claims 1 to 8, characterized in that a plurality of images (14) of the light pattern (40) reflected from the surface (13, 36, 37, 38) of the headlight (2) are successively captured by means of the camera system (9). Method according to claim 9, characterized in that successively acquired images (14) are compared with each other and only successively acquired images (14) which meet at least one specified conformity condition are used as the basis for adjusting the nominal light emission angle of the front headlight (2). A method according to any one of claims 1 to 10, characterized in that the method comprises the following steps: - determining a geometric relationship (α, hα) between an output light emission direction (7) of the headlight (2) and a direction (11) defining the current orientation of the front camera (9) based on at least one image (14) captured by means of a front camera (9) of the camera system, - determining the current pitch angle (β) of the front camera (9) above the ground (12) and / or the current yaw angle of the front camera (9) with respect to a longitudinal axis of the vehicle (1) based on images (14) captured by means of the front camera (9) during a journey of the vehicle (1), - controlling the nominal light emission angle of the headlight (2) based on the determined geometric relationship (α, hα) of the front camera (9) above the ground (12) and / or the current yaw angle of the front camera (9) with respect to a longitudinal axis of the vehicle (1) based on images (14) captured by means of the front camera (9) during a journey of the vehicle (1).hα) between the output light emission direction (7) of the front headlight (2) and the direction (11) defining the current orientation of the front camera (9) and based on the determined current pitch angle (β) and / or the current yaw angle of the front camera (9)., Device (28) for adjusting the nominal light emission angle of a front headlight (2) of a vehicle (1), comprising a camera system (9) and a device for adjusting the nominal light emission angle of the front headlight (2), characterized in that the device (28) is designed to receive (29) and evaluate images captured by means of the camera system (9) and to carry out a method according to one of claims 1 to 11. Vehicle (1) comprising a camera system (9), a device for adjusting the nominal light emission angle of the front headlight (2) and a device (28) according to claim 12 or designed to carry out a method according to any one of claims 1 to 11. Computer-implemented method comprising instructions which, when the program is executed by a computer, cause it to execute a method according to any one of claims 1 to 11. Computer program product comprising instructions which, when the program is executed by a computer, cause it to execute a method according to any one of claims 1 to 11. Computer-readable data carrier on which the computer program product according to claim 15 is stored. Data carrier signal that transmits the computer program product according to claim 15.

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