Headlight adjustment procedure

Abstract

Method for adjusting the headlights of a motor vehicle, in particular for generating difference images, with a headlight designed to produce at least one vehicle-specific light distribution, wherein the light distribution has a characteristic contour with characteristic points (p), and a camera used to record the light distribution of the headlight, characterized in that that the headlight is controlled, in particular moved, depending on the contour of the light distribution, such that the characteristic contour of the light distribution becomes visible in a difference image (d), in particular completely, The following step is performed to determine the headlight setting: a) Determining the coordinates of the characteristic points (p) in a coordinate system of the headlight, taking into account the current setting of the headlight.

Description

[0001] The invention relates to a method for adjusting the headlights of a motor vehicle, in particular for generating difference images, with a headlight designed to generate at least one vehicle-specific light distribution, wherein the light distribution has a characteristic contour with characteristic points, and a camera used to capture the light distribution of the headlight.

[0002] It is well known that headlights are used in motor vehicles to illuminate the road ahead. A fundamental requirement for good visibility in the dark is correct headlight adjustment. Only with properly adjusted headlights can it be ensured that other road users are not dazzled and that the road is optimally illuminated. Headlights produce different light functions, such as high beam, low beam, and the like, which must comply with specific legal regulations depending on the traffic situation. However, over the course of vehicle use, and especially during operation, the positions of the headlights can deviate from their original settings. This can be caused, for example, by temperature-related volume changes and settling processes in the headlight materials.These deviations can eventually lead to an undesirable shift in the light distribution and unacceptable glare. Therefore, the headlights must be readjusted after a certain period. A method for adjusting a vehicle's headlights, such as differential image analysis, can be used for this purpose. The camera can capture successive image sequences and analyze the differences between the images to determine the current position of the headlights. For this, the camera can project the light distribution onto a measuring wall or directly in front of the vehicle. This creates a light-dark boundary between the illuminated and dark areas, which has a specific characteristic contour for each light distribution.In the case of a glare-free light distribution, which can also be described as high beam distribution, the cut-off line exhibits a characteristic kink between a horizontal and a vertical area. In the case of low beam distribution, the cut-off line shows a characteristic rise between a slightly lower and a slightly higher horizontal area, and so on. The headlight adjustment system uses a camera to first detect incorrectly adjusted headlights, after which automatic adjustment can be performed. A crucial requirement for automatic headlight adjustment is the reliable detection of the relevant cut-off line. Therefore, accurate determination of the cut-off line has a significant impact on the adjustment result. However, this can be particularly difficult in unsuitable environments.A disadvantage that has emerged is that the light-dark boundary is often difficult to define and recognize. In particular, detecting the relevant light-dark boundary is difficult on surfaces with unevenness and / or markings, or in the presence of interfering ambient light. This unfortunately leads to unsatisfactory headlight alignment results and to glare for oncoming traffic.

[0003] WO 2012 / 048 795 A1 discloses a method for adjusting and / or calibrating at least one headlight of a vehicle.

[0004] It is therefore an object of the present invention to overcome at least one of the disadvantages described above, at least in part. In particular, it is an object of the present invention to provide a method for adjusting the headlights of a motor vehicle which enables improved generation of difference images and more precise headlight adjustment.

[0005] The aforementioned problem is solved by a method with the features of independent claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0006] The invention includes the technical teaching that the headlight can be controlled, in particular moved, depending on the contour (or shape) of the light distribution, such that the characteristic contour of the light distribution becomes visible, in particular completely, in a difference image. The combination of difference image analysis in conjunction with targeted headlight movement or control advantageously leads to robust detection of the headlight's light-dark boundary. To recognize the characteristic contour of the light distribution in the difference image, it is important to move the headlights in a direction appropriate to the respective situation and the respective light distribution. In an LED headlight, the LED matrix or the individual LEDs can be controlled according to the invention in such a way that the characteristic contour of the light distribution becomes visible in the difference image.The control of the spotlights depends on the contour of the respective light distribution, so that for each light distribution there is a suitable direction of movement or control in which the light-dark boundary in the image must move in order to achieve the best results.

[0007] The method according to the invention advantageously serves to determine an optimal headlight adjustment movement so that the light-dark boundary is clearly recognizable in the difference image. Using the image processing method of image subtraction (difference image analysis) and a targeted headlight movement, it can advantageously be ensured that all relevant edges and all characteristic points of the light distribution in the image can be separated from interfering edges and lines. Thus, the relevant light-dark boundary can be eliminated from the interfering factors, so that the light-dark boundary can be better recognized. This is advantageously achieved by combining the headlight movement (headlight adjustment) according to the invention with the image subtraction method.

[0008] By creating difference images, it is possible to remove static interference structures from the image, such as illuminated streetlights, the pattern of cobblestones, or road markings. To prevent the relevant edge of the light-dark boundary from disappearing when creating the difference image, the headlight is moved or controlled in a specific direction, calculated using the inventive method, according to the invention. The inventive concept lies in moving the headlight in such a way that the light-dark boundary is not in the same position in successive images captured by the camera, thus making a difference visible between the images in the difference image.For an optimal difference image, it is therefore necessary to prevent the headlights from being moved in such a way that the camera image does not move in the direction of an edge of the light-dark boundary occurring in the contour, as this part of the contour would otherwise not stand out clearly in the difference image.

[0009] According to the invention, changes or moving objects can be better represented in a difference image. This is because, in a difference image, disturbances such as ambient light, other light edges like side stripes, the surface structure of the projection surface, and ambient brightness can be filtered out more easily than when measuring light intensity using only a single image. The difference image can thus provide optimal information about the light-dark boundary of the light distribution, provided the headlight is moved or controlled optimally according to the invention. This results in a further advantage of the invention, namely that the inventive method for headlight adjustment leads to optimal headlight alignment. It is advantageous that the camera's measurement results are improved during the difference image analysis, and more precise positioning of the headlight can be ensured.

[0010] Since the resolution of the difference image is higher than that of a single image, headlight adjustment is advantageously no longer dependent on smooth, optimally positioned surfaces to detect the cut-off line, as is the case with conventional headlight adjustment methods. The inventive headlight adjustment method therefore makes headlight adjustment independent of the nature or selection of the projection surface. Consequently, any wall or the road area in front of the vehicle can be used as the projection surface. Even objects with complex surfaces, such as the rear of a motor vehicle, can serve to evaluate the cut-off line. Thus, a further advantage of the invention is achieved: the method can be carried out by the driver himself or even automatically, completely independently of professional assistance, for example, in a workshop.

[0011] The headlight adjustment is not only robust but also fast, as neither the headlight setting nor the headlight adjustment method requires significant computing power. Therefore, headlight adjustment can also be performed while the headlight is in operation. The implementation of the method according to the invention advantageously requires no additional hardware and can be implemented in existing systems. An existing camera, for example a front camera, can advantageously be used to capture the images.

[0012] According to the invention, the following step is performed to determine the headlight setting: a) Determining the coordinates of the characteristic points in a coordinate system of the headlight.

[0013] Advantageously, this is done without additional software or calculations, as only the current settings on the headlight need to be read. The coordinates of the characteristic points can then be determined as the corresponding headlight angles.

[0014] The procedure for determining the headlight setting may then include the following step: b) Transformation of the coordinates of the characteristic points into a coordinate system of the camera.

[0015] Determining the coordinates of the characteristic points in the camera system is important because the detection of the light-dark boundary is performed from the camera's perspective and must be optimized for the camera. To ultimately describe the direction of the headlight movement or control (in the case of LED headlights), the respective pattern of the light distribution from the camera's perspective must be evaluated. For this purpose, the characteristic points of the light distribution, described by their headlight angles, can be transformed from the headlight coordinate system into the camera coordinate system and thus converted into camera angles.

[0016] According to the invention, it can further be provided that the following step is carried out to determine the headlight setting: c) Determining direction vectors of the characteristic points in the camera's coordinate system, and d) in particular normalizing the direction vectors of the characteristic points in the coordinate system of the camera.

[0017] The transformed pattern (the multitude of all characteristic points) can then be evaluated based on direction vectors, which can yield a direction vector for the movement in the camera image. This movement can then be transformed back into the headlight coordinate system to calculate the adjustment angles for the headlight actuators. According to the invention, for an optimal difference image, care can be taken to ensure that the headlights are not moved or controlled in such a way that the camera image does not move in the direction of a straight line present in the contour of the light distribution, as this part of the contour would otherwise disappear in the difference image. According to the invention, all sections of the contour of the light distribution can be represented as vectors.Since the length of the segments plays no role in determining the direction of motion, the vectors can be normalized to a standard value. Since the opposite directions of the calculated vectors produce the same effect, they can be disregarded as directions of motion according to the invention.

[0018] According to one embodiment of the invention, the following step may be performed to determine the headlight setting: e) Determining the direction of movement of the headlight by bisecting an angle, in particular the largest angle, between two adjacent direction vectors.

[0019] This embodiment can also be described as angle bisecting. To minimize the influence of the excluded movement directions of the patterns on the movement, the optimal direction of movement can be determined by bisecting the largest angle between two adjacent vectors. This advantageously ensures that the camera does not move along an edge of the light-dark boundary and that this edge disappears in the difference image. The method of bisecting the largest angle is particularly advantageous in the case of low-beam distribution. In the case of glare-free light distribution, the smallest angle between two adjacent direction vectors can be bisected to determine the movement vector for the headlight. For angle bisecting, the direction vectors can first be placed at a common origin.Subsequently, according to one embodiment of the invention, the angle between the two adjacent vectors can be halved to determine a suitable motion vector for the headlight.

[0020] According to an alternative embodiment of the invention, the following step can be performed to determine the headlight setting: e) Determining the direction of movement of the headlight such that the difference area generated when moving the headlight has a maximum through all direction vectors, and in particular that the difference areas of the direction vectors do not overlap.

[0021] This achieves the advantage of maximizing the illumination of the light-dark boundary in the difference image, thus making it reliably visible. To calculate the maximum difference area, a direction of movement can be determined that spans the largest possible difference area between the direction vectors and also replicates the characteristic pattern shape. The direction of movement is also sought in which the sum of the difference areas spanned by all normalized direction vectors exhibits a maximum. To recognize the shape of the light distribution in the difference image, it is important to move the spotlights in a direction appropriate to the specific situation and light distribution, so that the characteristic shape of the light-dark boundary, with all its characteristic points and edges, is visible in the difference image. This can be advantageously ensured if the individual spanned areas do not overlap, if possible.

[0022] Furthermore, the invention may provide that the following step is carried out to determine the headlight setting: f) Transformation of the direction of motion, which was determined by bisecting the angle or by determining the maximum difference area, into the coordinate system of the headlight.

[0023] Furthermore, the method according to the invention can provide that the following step is carried out to determine the headlight setting: g) Representing the coordinates of the characteristic points in the coordinate system of the headlight.

[0024] This makes it advantageous to determine the desired direction of movement or control of the headlight in the coordinate system of the headlight in order to obtain the sharpest possible image of the light-dark boundary, so that the headlights can be moved or controlled accordingly.

[0025] Furthermore, the invention may provide that at least one of the following steps is carried out for headlight adjustment: h) Capturing an initial image at an initial point in time, i) Controlling or moving the headlight according to one of the aforementioned claims, j) Capturing a second image at a second time, k) Calculating a difference image between the first image and the second image.

[0026] A difference image is calculated by subtracting the values ​​of two consecutive individual images from each other. The difference image thus only shows the areas that have changed between these images. Image information that has not changed has the same value and is not displayed in the difference image. The advantage of the invention lies in the fact that the difference image can be displayed brighter and more clearly against the background than the representation of the headlight beam edge in a single image. This effect is used to more reliably detect the light-dark boundary and to more easily identify or eliminate interfering factors. Motion detection can be further improved by combining or adding multiple difference images.

[0027] Finally, the invention may provide that at least one of the following steps is carried out for headlight adjustment: l) Calculating the deviation between the current and the desired headlight position, in particular by comparing with predefined light distribution patterns, m) Controlling, in particular moving, the headlight to compensate for the deviation from the desired headlight position.

[0028] Advantageously, it can be detected whether the position of the light-dark boundary of the current light distribution deviates from the position of the predetermined light-dark boundary of the desired light distribution. Using a downstream pattern recognition routine, the current headlight position can be determined according to the invention based on the difference images. The pattern position with the highest degree of agreement with the difference image ultimately determines the current headlight position. The magnitude of the deviation from the desired position, as well as the vehicle position relative to the measuring wall or surface, can provide the required information about a correction value, according to which the headlight can be controlled or moved to generate the desired, specified light distribution.In the case of a movable headlight, this can involve a horizontal and a vertical offset by which the headlight can be pivoted about the horizontal and vertical axes. In the case of an LED matrix, the invention allows for a correction value based on rows and columns. In both cases, according to the invention, it may be sufficient to detect a deviation from the desired light distribution as described in step I) and to provide the user with corresponding information, for example in the form of a warning signal, that the headlight needs to be readjusted. Furthermore, step m) can be carried out by trained personnel in a workshop.

[0029] In summary, the invention provides a fast and robust method for optimally adjusting headlights in order to perform differential image analysis, which can ultimately lead to improved headlight alignment. Consequently, the invention achieves several further advantages, such as: • Determination of the horizontal and vertical position of the headlight, regardless of the nature of the projection surface. Any wall or the road surface in front of the vehicle can be used as the projection surface. Objects with complex surfaces, such as the rear of a vehicle, can also be used for evaluation. • Insensitivity of the difference images to disturbances such as external lighting, other light edges like side stripes, surface structure and ambient brightness. • Universal application of the method in movable swivel modules and in rigid LED matrix beam systems. • Time and computational efficiency through the simple implementation when evaluating the differences between successive images without complex algorithms for determining the light-dark boundary as in conventional methods.

[0030] According to the invention, the features described in the invention's method can be combined in a wide variety of ways, for example, in different embodiments. Further measures that improve the invention are described in more detail below, together with a description of preferred embodiments of the invention, with reference to the figures. The figures show: Fig. 1. Recording a difference image of a high beam distribution when the headlight is moved in three different directions, Fig. 2. Capturing a difference image of a low beam distribution, Fig. 3. Capturing a difference image of a high beam distribution, Fig. 4 characteristic points of a low beam distribution, Fig. 5 characteristic points of a high beam distribution for left-hand traffic, Fig. 5a characteristic points of a high beam distribution for right-hand traffic, Fig. 6 angle bisectors for low beam distribution, Fig. 7 angle bisectors for high beam distribution, Fig. 8 Example of two direction vectors, Fig. 9 maximum difference area in a direction of movement according to the invention, Fig. 10 Difference areas of individual vectors in a direction of movement according to the invention, Fig. 11 Difference areas of individual vectors in an unfavorable direction of motion, and Fig. 12 a difference area in the unfavorable direction of movement of the Fig. 11.

[0031] Fig. Figure 1 illustrates the problem of the invention for a high beam distribution using three examples a), b), and c), wherein examples a) and b) explain the problem underlying the invention and example c) realizes the inventive concept. As in examples a) and b) of the Fig. As shown in Figure 1, an edge of the light distribution can disappear from the difference image d if the headlights are moved in an unfavorable direction. This must be avoided, however, because otherwise the light-dark boundary in the difference image d will not be fully displayed. According to Example c), the object of the invention is to determine the direction r for the headlight adjustment that leads to an optimal difference image d in which all characteristic points and edges of the light distribution, i.e., the contour of the light distribution, are clearly and, in particular, completely displayed. The invention is based on the idea that the headlight must be moved in such a way that the camera image does not move in the direction of a straight line occurring in the contour of the light distribution, since this part of the contour would otherwise not be clearly visible in the difference image d (see Example c)).

[0032] In the case of a high beam distribution, which is in the Fig. As shown in Figure 1, the light-dark boundary comprises a horizontal and a vertical area. A difference image d (right column in the Fig. 3) can be calculated as the subtraction of the light intensities between image 2 (middle column in the Fig. 1) and a previous image 1 (left column in the Fig. 1) can be calculated. The difference image d can be represented as a binary image, where a bright point indicates that the light intensity is above a minimum value, and a dark point indicates that the light intensity is below the minimum value. To make the horizontal area visible as a change in the light distribution, the headlight can be controlled or moved in the vertical direction (see example a)). However, the vertical area then disappears from the difference image d. To make the vertical area visible as a change in the light distribution, the headlight can be controlled or moved in the horizontal direction (see example b)). However, the horizontal area then disappears from the difference image d. The aim of the invention is therefore to determine a direction of movement or a change in the light distribution for every light distribution that has a characteristic contour with characteristic points and edges.To find the control (in the case of an LED headlight) of the headlight in order to make the light-dark boundary, which can be determined as a change in the light distribution, visible in a difference image d.

[0033] Fig. Figure 2 shows three images: Figure 1 (top left), depicting the light distribution at time t1; Figure 2 (bottom left), depicting the light distribution at time t2; and a difference image (d) on the right. Figures 1 and 2 show a typical progression of a light-dark boundary in a low-beam distribution that a motor vehicle headlight can produce on a vertical measuring wall. A light-dark boundary forms between an illuminated and a dark area on the measuring wall. The progression of the light-dark boundary is formed by a horizontal line, a line rising to the right (in right-hand traffic) or to the left (in left-hand traffic), and another horizontal line, which blend smoothly into one another. Advantageously, the progression of the light-dark boundary can be clearly shown in the difference image (d), provided the headlight is controlled accordingly according to the invention.According to the inventive method, the vehicle can first be positioned perpendicular to a projection surface in order to project images 1 and 2 onto the projection surface. To capture the low-beam distribution, a camera can record and store images 1 and 2. To determine the change in the light distribution, the difference image d between image 2 and the previous image 1 is calculated. Using a downstream pattern recognition routine, the headlight position can be determined according to the invention based on the binary difference image d. According to the inventive method, the difference image d can be compared with a series of predefined low-beam patterns, each corresponding to a series of headlight positions. The headlight position of the pattern with the highest agreement with the difference image d can advantageously determine the current headlight position.Subsequently, the deviation between the determined current and a desired headlight position can be calculated, and the headlight can be retracted accordingly to compensate for this deviation.

[0034] Fig. Figure 3 also shows three images: Figure 1 (top left), which depicts the light distribution at time t1; Figure 2 (bottom left), which depicts the light distribution at time t2; and a difference image (d) on the right. Figures 1 and 2 each show a typical progression of a light-dark boundary in a glare-free light distribution, formed by a horizontal and a vertical line intersecting at a point. In the case of the high beam distribution, the headlight produces a so-called horizontal light-dark boundary, as shown on the right in the Fig. Figure 2 shows this. Determining the position of the headlight with a horizontal cut-off line therefore requires vertical and horizontal control of the headlight so that both sides are visible in the difference image d. To determine the change, the difference image d between the second image 2 and the previous image 1 is calculated. Using a subsequent pattern recognition routine, the headlight position can also be determined here based on the binary difference images d. The deviation from a desired headlight position, resulting in optimal light distribution, can then be determined. Finally, the headlight can be moved to the desired position according to the deviation.

[0035] The Fig. 4, Fig. 5 and Fig. Figure 5a shows that the light-dark boundary can be described using the characteristic points p of a light distribution. The contour of the light distribution is thus defined by the following points: four points in the Fig. 4, to describe the typical wedge of the light-dark boundary of the low beam distribution, and three points each in the Fig. 5 and Fig. 5a, to define the contour of the light-dark boundary of the glare-free light distribution, wherein the Fig. 5 the light distribution for left-hand traffic and the Fig. 5a shows the light distribution for right-hand traffic. On the axes of the Fig. 4, Fig. 5 and Fig. 5a The angle settings of the headlights can be specified as coordinates, whereby the vertical angles can be specified in the vertical plane and the horizontal angles in the horizontal plane in the headlight coordinate system.

[0036] The Fig. 6 and Fig. Figure 7 shows how the characteristic points are derived from the Fig. 4, Fig. 5 and Fig. 5a can be represented from the coordinate system of the headlights from the camera's perspective. Fig. Figure 6 shows normalized direction vectors v for a low beam distribution, as used, for example, in the headlight coordinate system in the Fig. 4 is shown. Fig. Figure 7 shows normalized direction vectors v for a glare-free light distribution, as used, for example, in the Fig. Figure 5a shows that the direction vectors v are placed at a common origin, which can correspond to one of the characteristic points p if the camera is pointed directly at that point. The tips of the direction vectors v, as shown in the Fig. 6 and Fig. Figures 7 show in which direction the camera must be pointed to obtain the remaining characteristic points p of the Fig. 4, Fig. 5 and Fig. 5a to be recorded directly.

[0037] The Fig. 6 and Fig. Figure 7 also shows an embodiment of the invention, according to which the following step can be carried out to determine the headlight setting: e) Determining the direction of movement r of the headlight by bisecting an angle α, in particular the largest angle α, of two adjacent direction vectors v1 and v2.

[0038] This embodiment is also referred to as angle bisecting. To prevent the headlight from being moved or controlled along an edge of the light distribution, and to prevent this edge from disappearing from the difference image d, the direction of movement r according to the invention can be calculated by bisecting the largest angle α between two adjacent vectors v1 and v2. This is particularly advantageous for the low beam distribution, which is used in the Fig. 4 and Fig. 6 is indicated. In the case of a glare-free light distribution, as in the Fig. 5, Fig. 5a and Fig. As shown in Figure 7, the smallest angle α between two adjacent direction vectors v1 and v2 can be bisected to determine the direction of movement r for the headlight.

[0039] Furthermore, the Fig. Figures 9 to 12 show an alternative embodiment of the invention, according to which the following step can be carried out to determine the headlight setting: e) Determining the direction of movement r of the spotlight such that the difference area f generated when moving the spotlight has a maximum fmax through all direction vectors v, and in particular that the difference areas f1, f2 of the direction vectors v do not overlap.

[0040] The maximum difference area fmax of two direction vectors v1, v2 is in the Fig. Figure 9 shows that when the difference area f = fmax is maximal, the light-dark boundary in the difference image d is maximally illuminated and thus reliably recognizable. Therefore, the invention proposes moving the spotlight in the direction of movement r that spans the largest possible difference area fmax between the direction vectors v1 and v2. This example also demonstrates that the difference area fmax replicates the characteristic pattern shape from a camera perspective, i.e., that the light-dark boundary of the light distribution lies within the difference area. Furthermore, the direction of movement r is sought in which the sum of the difference areas f1 and f2 of all normalized direction vectors r1 and r2 exhibits a maximum fmax, as further shown in the figure. Fig. 10 is indicated.

[0041] The Fig. Figure 10 shows a further requirement of the invention for reliably identifying the light-dark boundary in the difference image d. According to the invention, this can be achieved if the individual spanned surfaces f1 and f2 of the direction vectors v1 and v2 do not overlap as much as possible. Then the characteristic shape of the light-dark boundary, with all its characteristic points p, can be captured in the difference image d.

[0042] Should this not be the case and the headlight be pointed in a direction as shown in the Fig. 11 and Fig. If the vectors are moved 12, then the individual spanned areas f1 and f2 of the direction vectors v1 and v2 overlap, and the joint spanned area f is smaller than the maximum difference area fmax. As a consequence, the region Δf of the intersection of the difference areas f1, f2 disappears from the difference image d, since the subtraction of two equal light intensities results in zero in the difference image d. This leads to distorted results when detecting the light-dark boundary.

[0043] Therefore, it is important to comply with the invention, in particular with the requirements stated in the Fig. 9 and Fig. Figure 10 shows how to choose the direction of movement r of the spotlight such that the difference area f generated when moving the spotlight has a maximum fmax through all direction vectors v, and in particular that the difference areas f1, f2 of the direction vectors v do not overlap.

[0044] Once the direction of movement r for the headlight is determined (in the case of an LED matrix, the corresponding control), either by bisecting the angle or calculating the maximum difference area fmax, the direction of movement r can be translated back into the coordinate system of the headlight. According to the invention, the difference image d can then be formed, as described in the Fig. 2 and Fig. 3 is shown.

[0045] Finally, according to the invention, the deviation of the current position from the desired position of the headlight can be determined and the headlight can be controlled accordingly to compensate for this deviation.

[0046] The invention allows for the analysis of many different light distributions. Furthermore, the invention provides for the analysis of multiple difference images to further improve the detection of the light-dark boundary. To implement the method according to the invention and to control the headlight, appropriate software can be uploaded directly to the camera, the existing light control system, or the central control unit. Alternatively or additionally, a separate control unit can be provided for executing the method and / or controlling the headlight. Moreover, the invention allows the method to be applied not only to the headlight systems of a motor vehicle but also to other, different lighting systems.

[0047] It should also be obvious to a person skilled in the art that the invention is not limited in its implementation to the preferred embodiments specified above. Rather, individual features of the embodiments can be combined with one another, insofar as this is sensible and the combination does not leave the scope of the invention. Reference symbol list 1 first image 2 second picture d difference image f, common area f1, f2 individual areas Δf Intersection of surfaces f1, f2 fmax maximum difference area p characteristic points r preferred direction of movement t1, t2 first and second time points v Direction vectors v1, v2 direction vectors of two adjacent direction vectors

Claims

[1] Method for adjusting the headlights of a motor vehicle, in particular for generating difference images, with a headlight designed to produce at least one vehicle-specific light distribution, wherein the light distribution has a characteristic contour with characteristic points (p), and a camera used to capture the light distribution of the headlight, characterized by , that the headlight is controlled, in particular moved, depending on the contour of the light distribution, such that the characteristic contour of the light distribution becomes visible in a difference image (d), in particular completely, The following step is performed to determine the headlight setting: a) Determining the coordinates of the characteristic points (p) in a coordinate system of the headlight, taking into account the current setting of the headlight. [2] Method according to claim 1, characterized by , that the following step is performed to determine the headlight setting: b) Transformation of the coordinates of the characteristic points (p) into a coordinate system of the camera. [3] Method according to any of the aforementioned claims, characterized by , that the following step is performed to determine the headlight setting: c) Determining direction vectors (v) of the characteristic points (p) in the camera's coordinate system, and d) in particular normalizing the direction vectors of the characteristic points in the coordinate system of the camera. [4] Method according to any of the aforementioned claims, characterized by , that the following step is performed to determine the headlight setting: e) Determining the direction of movement (r) of the spotlight such that the difference area (f) generated when moving the spotlight has a maximum (fmax) through all direction vectors, and in particular that the difference areas (f1, f2) of the direction vectors (v) do not overlap. [5] Method according to any one of claims 1 to 3, characterized by , that the following step is performed to determine the headlight setting: e) Determining the direction of movement (r) of the headlight by bisecting an angle (α), in particular the largest angle (α), of two adjacent direction vectors (v1, v2). [6] Method according to one of claims 4 or 5, characterized by , that the following step is performed to determine the headlight setting: f) Transformation of the direction of movement (r) according to claim 4 or 5 into the coordinate system of the headlight. [7] Method according to any of the aforementioned claims, characterized by , that the following step is performed to determine the headlight setting: g) Representing the coordinates of the characteristic points (p) in the coordinate system of the headlight. [8] Method according to any of the aforementioned claims, characterized by , that at least one of the following steps is performed for headlight adjustment: h) Capturing a first image (1) at a first time point (t1), i) Controlling or moving the headlight according to one of the aforementioned claims, j) Capturing a second image (2) at a second time (t2), k) Calculating a difference image (d) between the first image (1) and the second image (2). [9] Method according to any of the aforementioned claims, characterized by , that at least one of the following steps is performed for headlight adjustment: I) Calculating the deviation between the current and the desired headlight position, in particular by comparing with given patterns of light distribution , m) Controlling, in particular moving, the headlight to compensate for the deviation from the desired headlight position.

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