Method and device for changing the light distribution of a vehicle lighting

Abstract

Method for changing the light distribution of a front lighting (60) of a vehicle (51) depending on an upcoming road curvature (50), comprising the steps: - Receiving an image or image sequence (21) from a forward-facing vehicle camera (1), - Recognition of at least one traffic sign (41, 42) that is a curve warning sign (41, 42) in the image or image sequence (21) that warns the driver of an upcoming road curve (50), characterized by, - that the light distribution (60) is changed depending on the detection of the at least one traffic sign (41, 42) which is a curve warning sign (41, 42), wherein the detected curve warning sign (41, 42) is part of a plurality of curve warning signs in the area of ​​the one road curve (50), wherein the distance (52) between the several curve warning signs (41, 42) and / or the distance (d) of a curve warning sign (41, 42) to the vehicle (51) is determined from the image (21) or the image sequence, wherein the curvature (r) of the upcoming road curve (50) which is marked with the curve warning signs (41, 42) is determined from the distance (52) between the several curve warning signs (41, 42) and / or the distance (d) of a curve warning sign (41, 42) to the vehicle (51).

Description

[0001] The present invention relates to a method and a device for changing a light distribution of a front lighting of a vehicle depending on an impending road bend, wherein an image or an image sequence is received from a forward-facing vehicle camera, traffic signs are recognized in the image or image sequence and at least one curve warning sign is recognized, and the light distribution of the front lighting of the vehicle is changed depending on the detection of the at least one curve warning sign. State of the art

[0002] From DE 601 29 647 T2 a device for automatically adjusting an optical axis of a vehicle headlight and a method for automatically adjusting the radiation area and the optical axis of the left and right front radiation of headlights are known, which are provided in a vehicle and are pivoted in connection with the steering angle of a steering wheel.

[0003] DE 10 2011 081 394 B3 discloses a method for highlighting an expected movement path of a vehicle, the method comprising a step of determining a traffic situation using information about an environment of the vehicle.

[0004] DE 10 2011 014 455 A1 discloses a method and a device for operating a vehicle with a lighting device. According to the invention, the light distribution of the lighting device is automatically adjusted upon detection of a construction site. Disclosure of the invention

[0005] The core of the present invention is to improve a method and a device for changing the light distribution of vehicle headlights so that curves or road bends ahead are even better illuminated. This is achieved by the features of the independent claims. Advantageous further developments and refinements are set out in the subclaims.

[0006] According to one aspect of the invention, the device according to the invention, in which the method according to the invention also runs, receives information in the form of signals from a video camera arranged forward in the vehicle, i.e. in the direction of travel. These signals, which represent image information, are examined to determine whether one of these images or an image sequence contains special traffic signs, in particular so-called curve warning signs, which warn the driver of an impending sharp road bend so that the driver can adjust their vehicle speed in good time. If such a curve warning sign is detected, the light distribution of the vehicle, in particular the front lighting of the vehicle, which illuminates the vehicle's surroundings in the direction of travel, is changed accordingly to achieve optimal illumination.Curve warning signs are traffic signs that are placed on the outside of a curved road and, depending on the country, indicate the direction of the road curve to the left or right using white and red arrow-shaped areas or black and yellow arrow-shaped areas or black and white arrow-shaped areas.

[0007] Advantageously, the detection of such a curve warning sign allows the driver to deduce the approximate radius of the upcoming road curve. Furthermore, the curve warning sign can be used to determine whether the upcoming road curve runs to the left or to the right, since the curve warning signs indicate the direction of the upcoming road curve due to their arrow-shaped symbolism.

[0008] Since such curve warning signs often do not occur as a single sign, but rather a large number of similar curve warning signs are placed along the entire curve, if a large number of curve warning signs are detected, the road curvature can be estimated even better in advance and the large number of curve warning signs can be detected individually, but processed as a single curve warning sign distributed over a larger area and the light distribution can be adjusted accordingly.

[0009] Furthermore, it is advantageous that the distance between several individual curve warning signs is determined from an image or image sequence captured by the vehicle camera. Additionally or alternatively, the distance of a curve warning sign from the vehicle is determined, so that the beginning of the curve curvature and the degree of curvature can be determined from this. It is particularly advantageous that the distance of the individual curve warning signs from the vehicle or the distance between the curve warning signs determines not only the quantitative degree of the road curvature, but also the radius of curvature of the curve.

[0010] It is particularly advantageous if the invention can be used to detect road bends whose radii of curvature are smaller than approximately 150 metres, since these are particularly sharp bends which are particularly difficult for the driver of a motor vehicle to see in poor visibility conditions or in the dark.

[0011] The distances between the curve warning signs determined according to the invention, the distance of the vehicle to the beginning of the road curve and the degree of curvature or the radius of the road curve are values ​​by means of which the light distribution of a vehicle can be particularly advantageously changed, so that the driver has an advantageously good overview of the upcoming road section. This change in the light distribution of the vehicle's front lighting can be achieved by horizontally pivoting headlights, which are pivoted towards the inside of the curve. In addition to or alternatively to pivoting headlights, it can be provided that one or more additional light sources are switched on and off and the axis of the light distribution is changed by widening or narrowing the illuminated area, the light distribution is thus pivoted.This means that a "swivel" of the light distribution can be achieved not only by swiveling the headlights, but also by adding or switching off additional light sources; the center axis of the light distribution can be swiveled without having to "swivel" the headlights, since this term refers to the virtual center line of the light distribution of the front lighting.

[0012] When changing the light distribution, it is particularly advantageous to pivot the vehicle's horizontally pivoting headlights toward the inside of the curve and only switch on the additional light sources when pivoting the headlights is no longer sufficient, thus pivoting the light distribution further toward the inside of the curve. This achieves particularly advantageous illumination of very tight curves.

[0013] Of particular importance is the implementation of the method according to the invention in the form of a control element provided for a control unit of a lighting control device of a motor vehicle. A program is stored on the control element which can be run on a computing device, in particular on a microprocessor or signal processor, and is suitable for carrying out the method according to the invention. In this case, the invention is therefore implemented by a program stored on the control element, so that this control element provided with the program represents the invention in the same way as the method for which the program is suitable. In particular, an electrical storage medium, for example a read-only memory, can be used as the control element.Further features, possible applications, and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, which are illustrated in the figures of the drawing. All described or illustrated features, individually or in any combination, constitute the subject matter of the invention, regardless of their summary in the patent claims or their references, as well as regardless of their wording or representation in the description or in the drawings. Short description of the drawings

[0014] Exemplary embodiments of the invention are explained below with reference to the drawings. They show: Fig. 1 a schematic representation of an embodiment of the device according to the invention, Fig. 2a a black and white representation of a curve warning sign indicating a road bend to the right, the black and white representation usually being in the colours red and white or black and yellow, Fig. 2b a schematic representation of a perspective view of an outer edge of a road curve, Fig. 3 a further schematic representation of a perspective view of a road section with a curved curve, Fig. 4a is a schematic plan view of a road section and a vehicle with light distribution according to the invention, Fig. 4b a further schematic plan view of a road bend with a vehicle with light distribution according to the invention and Fig. 5 a schematic flow diagram of the device according to the invention. Embodiments of the invention

[0015] Fig. 1 shows a schematic representation of the device according to the invention. It depicts a forward-facing vehicle camera 1 that outputs output signals to an electronic evaluation and control device 100. The control device 100 has an input circuit 2, via which input signals are received and fed to an evaluation and processing device 6 via a data exchange device 5. This evaluation and processing device can be a microprocessor or an ASIC, which, according to the invention, generates output signals from the input data. These signals are forwarded by the calculation and control device 6 via the data exchange device 5 to an output circuit 3 of the control device 100. Directly or indirectly, a plurality of lighting devices or lighting device controllers 60, 61 are connected to the output circuit 3, which are controlled according to the light distribution control according to the invention.One of the light sources 60 can be a vehicle front light capable of pivoting the light sources horizontally, so that a signal can be provided as the output signal of the control device 100 that informs the light source 60 at which angle to the vehicle's longitudinal axis the center axis of the light distribution should be pivoted. Additionally or alternatively, it can be provided that additional light sources 61 are provided, which are controlled by output signals from the output circuit 3 of the control device 100 and receive the output signals that merely indicate whether the light source should be switched on or off, but remain fixed in their orientation.

[0016] Through the Fig. 1, it is possible for images or image sequences of a driving situation in front of the vehicle to be recorded using a forward-facing vehicle camera 1, and for these image data to be forwarded to the control device 100. In the control device 100, the image data or image sequence data are forwarded to a computing and evaluation device 6, in which the method according to the invention is executed. Provision is made for the supplied image data or image sequence data to be searched for an existing pattern that indicates the presence of curve warning signs.If one or more such curve warning signs are detected, the position of these patterns in the image frame and their change can be used to infer properties of the road curvature, such as the start of the road curvature, the degree of the road curvature, the radius of the road curvature and the direction of the road curvature, and corresponding control signals can be generated which are output by the evaluation and computing device 6 to the output circuit 3 of the control device 100 and from there to the connected lighting devices or lighting control devices 60, 61 in order to change the light distribution according to the invention such that the driver is provided with timely and optimal illumination of the road curvature.

[0017] In Fig. 2a shows a curve warning sign 41, which shows an exemplary embodiment. Arrow-shaped wedges are provided on the curve warning sign 41, which indicate the direction of the upcoming road curve, which in this case is the Fig. 2a is a road bend that runs to the right. Fig. 2a The sections shown in black and white are colored depending on the country of installation. In some countries, it is customary to display this black and white representation in red and white arrow segments; however, it is also possible for these arrow segments to be displayed in a black and white or black and yellow color combination.

[0018] In Fig. Figure 2b shows an example of a driving situation as it can be recorded by the vehicle camera 1. A roadway 50 curved to the left can be seen, at the outer edge of which a guardrail 56 is mounted. Above this guardrail 56, a plurality of curve warning signs 42 are shown, which are distributed over the area of ​​the road curve 50. In contrast to the curve warning sign 41, as shown in Fig. As shown in Figure 2a, the curve warning signs 42 of the Fig. 2b is designed such that only one arrow segment is printed per curve warning sign 42. However, these smaller curve warning signs 42 are usually placed in their multitude over the entire curve of the road curve 50, so that from the distribution of these curve warning signs 42, each with an arrow segment, one can deduce the length of the road curve and the radius of the road curve 50. The Fig. 2b The curve warning signs 42, which are also shown in black and white, are in reality shown in colour depending on the country and can appear in the colour combinations red and white, black and white or black and yellow.

[0019] In Fig. 3 shows an example of another driving situation, as can be recorded by the vehicle camera 1. The content of the camera image 21 recorded by the vehicle camera 1 shows a road 50 with a road curve bending to the left. Furthermore, the left edge 54 of the road and the right edge 55 of the road are shown, each viewed in the direction of travel. Likewise, the center line 53, which separates the two lanes in the direction of travel, is visible in the image. At the outer edge of the curve, as shown in Fig. 2b, curve warning signs 51 are set up, each having a segment of a directional arrow. Based on the image processing of the recorded camera image 21, the positions of the curve warning signs 51 within the camera image 21 can be determined, and the distances 52 between the distributed curve warning signs 51 can be roughly determined. It is also conceivable that not only a single camera image 21 is captured, but rather a sequence of camera images is recorded, and the position and distance of the curve warning signs 51 from the driver's own vehicle can be determined from the change in the positions of the curve warning signs 51 in the individual images 21 of the image sequence, as well as from the change in the size of the curve warning signs 51 across the individual images 21 of the image sequence.Knowing the distance and position of the curve warning signs 51 from the vehicle, it is also possible to determine the course of the road curve 50, for example, by determining the distance d of the beginning of the road curve 50, determining the radius r of the road curve 50 and possibly the center point M of the curve radius, and / or determining the length of the road curve 50 to be traversed. Knowing these variables, which describe the direction and degree of the road curve ahead, it is possible to control the vehicle's front lighting in such a way that the driver can be provided with a timely and optimally illuminated road curve.This increases driving comfort and safety, particularly in poor visibility conditions due to bad weather or darkness, as the driver can adapt his driving behaviour and vehicle speed to the conditions of the road curvature in good time and can recognise any hazards on the roadway 50 in good time.

[0020] Likewise, the position of the curve warning signs 42 relative to the vehicle 51 can be used to determine the distances 52 between the curve warning signs 42, which allows the degree of curvature to be deduced. This assumption is possible because the more curve warning signs 42 are positioned, with smaller distances 52, the tighter the curve ahead. Thus, from the knowledge of the distance 52 between the curve warning signs 42, a rough deduction can be made about the degree of curvature of the upcoming road bend 50. This can provide improved illumination of the road curvature even in cases where an exact determination of the curve radius r cannot be determined.

[0021] In Fig. 4a shows a schematic plan view of a road 50 running to the right. Curve warning signs 42 are shown on the outer edge of the curve, providing timely warning to the driver of the sharp right-hand bend. The vehicle camera 1 provided in the vehicle 51 now makes it possible for the curve warning signs 42 to be recognized as curve warning signs, and for the distance d and radius r of the upcoming road curve to be deduced from the distance of the curve warning signs 42 from the vehicle 51 as well as the distance between the curve warning signs 42. Knowing this curve-descriptive information d, r allows the front lighting devices of the vehicle 51 to be controlled in a timely manner so that the light cone 60 of the vehicle 51 optimally illuminates the upcoming right-hand bend.This can be achieved by pivoting horizontally pivotable vehicle headlights and / or by switching individual light sources in the headlight on or off and / or by switching cornering lights on and off, whereby the center axis of the light distribution of the vehicle's front lighting can also be pivoted to the left or right. According to the present invention, it is also possible for horizontally pivotable headlights to be pivoted towards the inside of the curve upon detection of a road bend ahead. If it is detected that the horizontal pivoting of the vehicle headlights is insufficient to optimally illuminate the curve, additional cornering lights can be switched on in order to be able to adequately illuminate even curves with an extremely small curve curvature radius r.This makes it possible to detect danger points 56 on the inside of the curve of the roadway 50 as early as possible and thus to react appropriately to the danger point 56 ahead.

[0022] In Fig. Figure 4b shows another driving situation in which vehicle 51 is moving along a roadway 50 toward a bend in the road ahead. The vehicle camera 1 mounted in vehicle 51 detects the curve warning signs 42 located ahead, and the degree of curvature and the position of the curve are determined based on their distance and position from the vehicle 51, as well as the distance between the curve warning signs 42. As vehicle 51 approaches the curve warning signs 42, the light distribution 60 of the low beam of vehicle 51 is shown, as it illuminates the road ahead when driving straight ahead.After the curve warning signs 42 have been detected by the vehicle camera 1, the radius of curvature r and the distance d of the upcoming curve of the road 50 are determined in the evaluation and calculation device 6 of the control unit 100, and the light distribution 60 is pivoted toward the inside of the curve by means of horizontally pivotable lighting devices, resulting in the light distribution 62 and, subsequently, the light distribution 63, which better illuminate the curve ahead. For particularly sharp curves, it is now possible to additionally switch on a cornering light 61 on the inside of the curve, so that the inside edge of the roadway is illuminated and hazard areas 56 on the inside edge of the roadway ahead can be detected early.According to the invention, it can also be provided that the horizontally pivotable lighting devices are pivoted in the direction of the inside of the curve when a road curve is detected ahead, and only when further horizontal pivoting of the light distribution 63 is no longer possible is a cornering light 61 switched on on the inside of the curve in order to detect the inside edge of the road curve and the danger points 56 located there in good time.

[0023] In Fig. 5 shows an example of a flow diagram of an embodiment of the method according to the invention. After starting the method according to the invention, which can occur when the vehicle ignition is switched on or after the vehicle lights are switched on, the control device 100 and the vehicle camera 1 are activated. During the course of driving, the vehicle camera 1 records images and image sequences of the driving situation ahead and forwards them to the control device 100. In the control device 100, in which the method according to the invention is executed, an image 21 from the vehicle camera 1 or an image sequence consisting of several consecutive images 21 from the vehicle camera 1 is read into the control device 100 in step S01. In the subsequent step S02, the image 21 or the image sequence consisting of images 21 is processed using pattern recognition.In this case, patterns of traffic signs stored in a memory are to be recognized in image 21. Within the scope of the present invention, in particular, the presence of one or more curve warning signs 41, 42, as shown in . Fig. 2a and Fig. 2b. The search for patterns of curve warning signs does not have to be exhaustive, since such a video-based driver assistance system can have further assistance functions for which the presence of other traffic signs, for example signs regarding speed limits, can be recognized. In the following sequence, the method branches into the parallel steps S03 and S04, wherein in step S03 curve information is determined or estimated from image 21 by determining distances 52 between the curve warning signs 42, and possibly further information such as the curve radius r is determined or estimated. In parallel to this, in step S04 the distance d of at least one of the curve warning signs 42 is determined so that the distance of the vehicle 51 to the beginning of the road curve can be estimated. These two parallel steps S03 and S04 can alternatively also run one after the other.In step S05, a check is now carried out to determine whether the vehicle 51 has already reached the beginning of the road curve, i.e., whether the distance d has become approximately zero. If this is not the case, i.e., whether the distance d to the beginning of the road curve is greater than zero, S05 branches to "N" and runs through the previously described steps again, starting from step S01, until the beginning of the road curve is reached. If it was determined in step S05 that the vehicle 51 has reached the beginning of the road curve, and thus the distance d has become approximately zero, step S05 branches to "Y" and, in the subsequent step S06, control signals for the vehicle's front lighting 60, 61 are output. These control signals can be the output of a horizontal pivot angle for vehicle lighting that can be pivoted horizontally, so that the light distribution can be pivoted towards the inside of the curve.In addition, it is possible to output on / off information by means of which individual segments of a vehicle's lighting can be switched on or off, or an additional cornering light can be switched on or off. According to a particularly advantageous embodiment, only the angle for horizontally pivotable vehicle lighting is output in step S06, and the signal for switching the additional cornering light on or off is output in optional step S07. This makes it possible for the horizontally pivotable vehicle lighting to pivot the light distribution towards the inside edge of the roadway. Only when further pivoting of these lighting sources is no longer possible after step S06 is the additional cornering light switched on in the subsequent step S07.After completing the curve, the lighting devices are swiveled back to the central position, the cornering lights are switched off and the process is ended in the “End” step or started again with the “Start” step.

[0024] This in Fig. 5, in addition to being used for controlling the lighting of a vehicle 51, the method described can also be used for other driver assistance functions, for example for a lane keeping function that supports the driver in preventing him from accidentally leaving the lane he is currently traveling in. In this case, no lighting devices are controlled, but in the case of a lane departure warning, warning devices are output to warn of unintentional departure from the lane to the left or right, or in the case of lane keeping support, control signals for a steering device are output to the downstream control elements.

Claims

[1] Method for changing a light distribution of a front lighting (60) of a vehicle (51) depending on an upcoming road curvature (50), comprising the steps: - receiving an image or image sequence (21) from a forward-facing vehicle camera (1), - detecting at least one traffic sign (41, 42) in the image or image sequence (21) which is a curve warning sign (41, 42) and which warns the driver of an impending road bend (50), characterized by , - that the light distribution (60) is changed depending on the detection of the at least one traffic sign (41, 42) which is a curve warning sign (41, 42), wherein the detected curve warning sign (41, 42) is part of a plurality of curve warning signs in the region of the one road bend (50), wherein the distance (52) between the plurality of curve warning signs (41, 42) and / or the distance (d) of a curve warning sign (41, 42) from the vehicle (51) is determined from the image (21) or the image sequence, wherein the curvature (r) of the upcoming road bend (50) marked with the curve warning signs (41, 42) is determined from the distance (52) between the plurality of curve warning signs (41, 42) and / or the distance (d) of a curve warning sign (41, 42) from the vehicle (51) becomes. [2] Method according to claim 1, characterized by that the approximate radius (r) of the upcoming road curve (50) is determined from the detection of at least one curve warning sign (41, 42). [3] Method according to one of the preceding claims, characterized by that from the detection of the curve warning sign (41, 42) it is determined whether the upcoming road curve runs to the left or to the right. [4] Method according to one of the preceding claims, characterized by that road curvatures (50) are determined with radii of curvature (r) of less than about 100 meters. [5] Method according to one of the preceding claims, characterized by that the light distribution of the front lighting (60, 61) of the vehicle (51) is changed by pivoting horizontally pivotable headlights (60) and / or by switching additional light sources (61) of the vehicle (51) on and off. [6] Method according to claim 5, characterized bythat in order to illuminate the detected road curvature (50), the horizontally pivotable headlights (60) are pivoted towards the inside of the curve and the additional light sources (61) are only switched on when the pivoting of the headlights (60) is no longer sufficient to illuminate the curve. [7] Method according to one of the preceding claims, characterized by that the additional light sources (61) are curve lights and / or cornering lights. [8] Device for controlling the light distribution of a front light (60, 61) of a vehicle (51), characterized bythat the device (100) is supplied with images (21) or image sequences (21) of a vehicle camera (1) directed forward depending on an impending road bend (50), and the light distribution of the front lighting (60, 61) of the vehicle (51) is changed depending on curve warning signs (41, 42) detected in the images (21) or image sequences (21), wherein the detected curve warning sign (41, 42) is part of a plurality of curve warning signs in the region of the one road bend (50), wherein the distance (52) between the plurality of curve warning signs (41, 42) and / or the distance (d) of a curve warning sign (41, 42) to the vehicle (51) is determined from the image (21) or the image sequence, wherein the distance (52) between the plurality of curve warning signs (41, 42) and / or the distance (d) a curve warning sign (41, 42) to the vehicle (51) the curvature (r) of the upcoming road curve (50) which is marked with the curve warning signs (41, 42),is determined., [9] Device according to claim 8, characterized by , the device (100) outputs signals with which a horizontally pivotable headlight (60) is pivoted and / or a cornering light (61) is switched on and off and / or a turning light (61) is switched on and off.

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