CN117584847A

CN117584847A - Device and method for illuminating a front region of a vehicle

Info

Publication number: CN117584847A
Application number: CN202311025443.1A
Authority: CN
Inventors: N·马蒂亚斯; V·西蒙
Original assignee: Hella GmbH and Co KGaA
Current assignee: Hella GmbH and Co KGaA
Priority date: 2022-08-16
Filing date: 2023-08-15
Publication date: 2024-02-23
Also published as: DE102022120577A1

Abstract

The invention relates to a device for illuminating a front area (1) of a vehicle, comprising: a lighting unit (3) integrated in the vehicle (2) for producing a predefined light distribution in the front region of the vehicle; a detection unit (6) for detecting objects (O1, O2) and/or ambient lighting (8) in a front region of the vehicle; a control unit (7) for controlling the light emitting unit (3); a computing unit (10) for processing and/or analyzing evaluation data, the detection unit having: a device for detecting the brightness of an object, a device for detecting the ambient illumination of a front area of a vehicle, which is generated by a light source (9) arranged outside the vehicle, the computing unit having: means for calculating a current contrast (K1, K2) of the object, and means for calculating a changed contrast (K1 ', K2') of the object, means for generating a control signal (14) for the lighting unit depending on a comparison of the current contrast of the object and the calculated contrast of the object.

Description

Device and method for illuminating a front region of a vehicle

Technical Field

The invention relates to a device for illuminating a front area of a vehicle, comprising: a lighting unit integrated in the vehicle for producing a predetermined light distribution in the front region of the vehicle; a detection unit for detecting an object and/or ambient lighting in a front region of the vehicle; a control unit for controlling the light emitting unit; a computing unit for processing and/or analyzing the evaluation data.

The invention also relates to a method for controlling a lighting unit of a vehicle, wherein the lighting unit illuminates a front area of the vehicle, which is additionally illuminated by ambient illumination from another direction, and an object located in the front area of the vehicle is detected when determining the location or position of the object in the front area of the vehicle.

Background

DE102005041234A1 discloses a device for illuminating a front region of a vehicle, comprising a lighting unit having a plurality of light-emitting elements (LED light sources) which are arranged in a matrix and can be actuated individually, so that the lighting unit is actuated as a function of detection data provided by means of a detection unit for an object in the front region of the vehicle, such that the object is illuminated at a reduced brightness, so that the object, for example, configured as a further traffic participant, is not blinded.

For identifying objects, it is known, for example, from DE102018123779A1 to use lidar sensors.

It is known from EP3090913B1 to use a camera as a detection unit for identifying objects. By means of the computing unit, possible objects are identified from the image data of the front region of the vehicle.

EP3070641B1 discloses a device for illuminating a front region of a vehicle, which has a detection unit configured as a stereo camera for detecting an object. Object detection is performed with the generation of light distribution of different patterns caused by the light emitting unit.

However, object detection becomes difficult when environmental conditions are not ideal and the reflectivity of the object itself is unfavorable compared to the environment. In particular when the ambient lighting is road lighting, which is fixed in position, a relatively high background brightness is achieved behind the object. If the reflectivity of an object is relatively low, the contrast between the object and the environment may be so small that the object cannot be located or otherwise identified. It is desirable to produce sufficient contrast of the object with respect to its surroundings by changing the illumination of the object by the lighting unit of the vehicle.

Disclosure of Invention

The object of the present invention is therefore to further develop a device and a method for illuminating a front region of a vehicle in such a way that an illumination of an object adapted to the surrounding environment conditions is achieved, wherein an optical identification of the object is ensured.

To solve this task, the invention is characterized in that, in combination with the preamble of claim 1, the detection unit has as detection data: means for detecting the brightness of an object, means for detecting the ambient illumination of a front area of a vehicle, the ambient illumination being generated by a light source arranged outside the vehicle, the computing unit having: the device comprises means for calculating the current contrast of the object from the detection data, means for calculating the contrast of the object as a function of the illumination state of the object which can be occupied by the variable actuation of the lighting unit and as a function of the ambient illumination of the object, and means for generating an actuation signal for the lighting unit as a function of a comparison of the current contrast of the object with the calculated contrast of the object.

A particular advantage of the invention is that an optimal illumination of the object in the front region of the vehicle can be achieved by determining the current contrast of the object with respect to its surroundings. The lighting units illuminating the front region of the vehicle are controlled in a modified manner in such a way that high background brightness behind the object due to ambient lighting, in particular road lighting, can be compensated. If the background brightness of the object is relatively high due to road illumination, for example, a negative contrast can be produced by reducing the illumination intensity of the object from the front by the light emitting unit, so that a relatively dark object in front of a bright background can be recognized. This can be achieved, for example, by targeted dimming of at least the light-emitting elements of the illumination object.

According to one refinement of the invention, the control signals for controlling the light-emitting units are selected from a control database of the device, in which classified parameters relating to the reflectivity of the object and to the current ambient lighting are stored, so that an optimized light distribution can be produced using the corresponding control signals.

According to a further development of the invention, the control signal relates only to a light-emitting element provided for illuminating the object. The illumination of other areas of the front area of the vehicle in which no object is located remains unchanged.

According to a preferred embodiment of the invention, the light-emitting unit is configured as a high-resolution headlight with a plurality of individually controllable light sources or an LCD display or a micromirror array. In this way, the light distribution can be adapted specifically as a function of the determined contrast of the object.

According to one refinement of the invention, the device has a calculation unit, so that a first contrast of the object in the case of the light-emitting unit being switched on is calculated and a second contrast of the same object in the case of the light-emitting unit being switched off is calculated. The determined contrast values are then compared, whether the first contrast or the second contrast has a higher contrast value. The control signal for the lighting unit is selected in dependence on the comparison such that the lighting element provided for illuminating the object is switched on or off. Advantageously, the database can be dispensed with in the case of such a manipulation of the lighting unit.

According to one refinement of the invention, the computing unit has means by which the contrast values of a plurality of objects are determined when the light-emitting unit is switched on or off. From the following two possible combinations, on the one hand, the combination of the first object and the second object with the light emitting unit turned on and, on the other hand, the combination of the second contrast of the first object and the second object with the light emitting unit turned off, the combination providing the maximum contrast value as the comparison value is selected. In this way, an optimized illumination of a plurality of objects is ensured in a simple manner in the case of a headlight which is not provided with high resolution.

According to a further development of the invention, the actuation signal for the light-emitting unit is determined from the determined reflectivity of the object. Preferably, the reflectivity of the object is obtained by comparing the obtained luminance data of the object with a reference table.

According to a further development of the invention, the control signals for the lighting units are controlled in accordance with a road illumination database in which road illumination of different intensities and/or different types of road illumination are summarized with illumination levels. The manipulation signal can be defined by comparing the current road illumination due to the detection of ambient illumination with illumination levels stored in a road illumination database. Advantageously, the number of different control devices of the lighting unit can thereby be reduced.

According to a further development of the invention, the detection unit has a camera and/or a radar sensor and/or a lidar sensor. The camera provides image data of the front region of the vehicle from which luminance data can be extracted as a function of position.

To solve this task, the invention is characterized in that, in connection with the preamble of claim 11: the brightness of the object and the brightness of the surroundings of the object are determined, the contrast of the object is determined by comparing the brightness data of the object with the brightness data of the surroundings or by comparing the determined brightness data of the object and the surroundings with reference data, at least one further contrast of the object is calculated in the case of a modified actuation of the lighting unit, and the actuation signal for actuating the lighting unit is changed if the calculated modified contrast is greater than the current contrast of the object.

A particular advantage of the method according to the invention is that an optimization of the illumination of the object can be achieved by comparing the current contrast of the object in the front region of the vehicle with data stored and/or calculated in the event of a change in the actuation of the lighting unit. In this case, the current contrast of the object is preferably compared with a minimum achievable contrast value and/or with a maximum achievable contrast value due to the lighting unit and the corresponding defined environmental conditions. The resulting object contrast improvement promotes better recognition of objects in the surrounding environment of the front region of the vehicle.

Further advantages of the invention result from the further dependent claims.

Drawings

Embodiments of the present invention are explained in detail below with reference to the drawings.

In the drawings:

figure 1 shows a schematic view of a lighting device,

fig. 2 shows a flow chart of a control method of a headlight in order to optimally illuminate an object in a front region of a vehicle, and

fig. 3 shows a graph of the illumination distance to be adjusted of the light-emitting element of the headlight responsible for illuminating the object, as a function of the road illumination level and the reflectivity of the object.

Detailed Description

The device according to the invention for illuminating the front region 1 of a vehicle is arranged integrally in the vehicle 2. The device comprises a lighting unit 3 for generating light 4 by means of which a predefined light distribution, such as a low beam distribution, a rural road light distribution, a city light distribution, etc., is generated. The light-emitting unit 3 is configured as a headlight, preferably as a high-resolution headlight.

The high-resolution headlight has, for example, a plurality of light-emitting elements which are arranged in a matrix and can be actuated individually, wherein the light-emitting elements are configured as LED light sources. Alternatively, the high-resolution headlight may also have a liquid crystal panel with a plurality of liquid crystal elements which can be actuated individually and which allow the light emitted by the light source to pass through or block the light emitted by the light source, respectively. Alternatively, instead of such a liquid crystal arrangement (LCD arrangement), a surface-modifying device with a DMD element (digital micromirror device) may also be provided, wherein individually controllable micromirrors transmit or not transmit light. The high-resolution headlight thus enables a region blanking or dimming of the light distribution, so that glare of objects, such as pedestrians, is avoided.

Furthermore, the device according to the invention comprises a detection unit 6 for detecting objects in the front area 1 of the vehicle. The front area 1 of the vehicle detected by the detection unit 6 is not limited to a distance of, for example, 40 meters from the object to the vehicle. The object can also be arranged farther from the vehicle 2 so that the vehicle front zone 1 reaches a distance of more than 40 meters from the vehicle 2. The size and in particular the length of the front area 1 of the vehicle, which extends along the longitudinal axis of the vehicle 2, is dependent on the effective distance of detection of the detection unit 6. The detection unit 6 may, for example, have a camera 6' which records an image of the vehicle front zone 1 and supplies it to an electronic control unit 7. Furthermore, the detection unit 6 may have a lidar sensor and/or a radar sensor, not shown, in order to determine the distance to the identified object.

The camera 6' is able to determine, inter alia, the brightness of the detected object. The camera 6' can also be used to detect or determine, among other sensors, the ambient lighting or the ambient brightness, so that the influence of the street lamp 9 on the road lighting 8 can be estimated or determined. Because the street lamp 9 is arranged a few meters above the road, the road lighting 8 takes place substantially perpendicular to the road. As a result, objects, such as persons, cannot be illuminated well. Instead, there is a relatively bright background. If the object is additionally illuminated on the front side by the lighting unit 4, the object appears bright in front of a bright background. As a result, the contrast is lowered, and the object cannot be recognized well. The invention provides a method or device for optimizing the contrast of an object on a road or in a front region of a vehicle. The lighting unit 3 is controlled in a modified manner as a function of the ambient illumination 8 and the reflectivity of the object, so that a sufficient contrast of the object is ensured for identifying the object.

In the present embodiment according to fig. 1, it is assumed that the first object O1 and the second object O2 are located in the vehicle front zone 1 substantially at the same distance from the vehicle 2. The objects O1, O2 are persons, wherein the first object O1 has a clothing with a reflectivity of 50% and the second object O2 has a clothing with a reflectivity of 15%. Additionally, the objects O1, O2 are illuminated by the road illumination 8 substantially from above. If the lighting unit 3 is in an on-state, for example in order to generate a city light distribution, the second object O2 with a lower reflectivity has such a low contrast with respect to the environment that it cannot be visually recognized. Only the first object O1 is visually identifiable due to the high reflectivity. According to the invention, the light-emitting elements of the light-emitting unit 3 are actuated such that the objects O1, O2 either have a positive contrast (the object appears bright against a dark background) or have a negative contrast (the object appears dark against a bright background).

In order to meet the object, the control unit 7 has a calculation unit 10 in which an algorithm for optimizing the contrast of the objects O1, O2 is contained. As can be seen from fig. 2, in a first step S1, object recognition of the first object O1 and of the second object O2 takes place by means of the sensors of the detection unit 6. The camera 6' of the detection unit 6 measures on the one hand the brightness of the first object O1 and the second object O2 and the ambient brightness with respect to the objects O1, O2, so that the type of road illumination 8 can be estimated based on these detection data.

In a second step S2, the reflectivity of the identified objects O1, O2 is determined. For this purpose, the camera 6' determines the brightness of the first object O1 and the second object O2. The reflectances of the first object O1 and the second object O2 can be found by comparison with the reference values (reference data) stored in the reference database 11. The reflectivity of the objects O1, O2 of course takes into account the illumination thereof by the light emitting unit 3.

In a third step S3, the achievable or changed contrast of the objects O1, O2 is calculated such that they can be detected in the lighting state that is changed relative to the current lighting state before the background. For this purpose, an algorithm running in the computing unit 10 is provided. According to a first variant of the actuation of the lighting unit 3, the lighting unit 3 is actuated according to the diagram 13 shown in fig. 3 stored in the actuation database 12. It is assumed that in step S1 the current road illumination 8 can be estimated so that there is one of the road illumination levels M3, M4, M5, M6 according to DIN EN 13201-2. These road illumination levels M3, M4, M5, M6 exhibit road illumination parameters that differ in classification. From M6 to M3, the road illumination intensity increases. Further, it is assumed that the reflectivities S2 of the objects O1, O2 are determined. In the case of using the graph 13, the result is obtained for the first object O1 having a reflectivity of 50% and the road illumination level M4 that the light-emitting unit 3 should be switched on or that a light-emitting element for illuminating the first object O1 is provided and therefore the first object O1 should be illuminated. For a second object O2 with a reflectivity of 15%, it follows from the graph 13 that this second object should not be illuminated by the lighting unit 3, so that in this case a negative contrast will occur, which is sufficient for identifying the second object O2. Positive contrast will occur with respect to the first object O1 because the first object O1 appears significantly brighter than the background. The present embodiment relates to objects O1, O2 arranged substantially at the same distance from the vehicle 2. Thus, the graph 13 is only a part of a total graph, not shown, which provides values according to the distance of the objects O1, O2 from the vehicle 2. If the objects O1 and O2 are located at different distances or additional distances from the vehicle, the overall chart has a different adjustment value for the distance than chart 13.

In a next step S4, the light emitting unit 3 is operated, wherein the individually operable light emitting elements of the light emitting unit 3 are operated such that the first object O1 is illuminated and the second object O2 is not illuminated. After the end of step S4, step S1 and subsequent steps S2, S3 and S4 are repeatedly performed. Thus, steps S1, S2, S3, S4 are repeatedly performed, ensuring an optimization of the contrast of the objects O1, O2 depending on the varying environmental conditions and/or the objects O1, O2 themselves.

According to an alternative variant, the contrast of the first object O1 and the second object O2 can be calculated in the calculation unit 10, wherein the contrast is determined from the difference between the brightness of the object O1 or O2 and the ambient illumination, which is related to the brightness environment recognition. Alternatively, another measure of the recognizability of the objects O1, O2, for example the ratio of the contrast to the contrast threshold value, can also be calculated. The contrast threshold is an experimentally determined value and is related in particular to the object size and the ambient brightness.

The computing unit 10 performs a plurality of computing processes. On the one hand, the contrast K1 of the first object O1 and the contrast K2 of the second object O2 in the state where the light emitting unit 3 is currently on are calculated. Furthermore, a calculation process is performed in which the contrast K1 'of the first object O1 and the contrast K2' of the second object O2 are calculated with the light emitting unit 3 turned off. If necessary, a further contrast K1″ of the first object O1 and a further contrast K2″ of the second object O2 in the on state of the light-emitting unit 3, which is provided for the dimming of the light-emitting elements of the first object O1 and the second object O2, can be calculated. Then in another calculation step according to

max(K1、K1’；K1”…)＝K1 _max ；

max(K2、K2’、K2”…)＝K2 _max

Selecting the determinedThe maximum contrast value K1 of the contrast values K1, K1 'or K2, K2' _max 、K2 _max 。

Maximum value K1 of these contrast values for different objects O1, O2, respectively _max 、K2 _max Corresponding to the on-state or off-state of the light-emitting element or the illuminance in the dimmed state of the light-emitting element of the corresponding object O1, O2. Therefore, the maximum contrast value K1 _max Or K2 _max Which corresponds to the control values for the lighting unit 3. In the present embodiment, K1 _max It will mean that the first object O1 will be illuminated by the corresponding light emitting element of the light emitting unit 3. In the present embodiment, K2 _max Meaning that the second object O2 will not be illuminated, i.e. the corresponding light emitting element of the light emitting unit 3 has to be turned off. Thus, the manipulation signal 14 transmitted from the control unit 7 to the light emitting unit 3 is modified such that the light emitting element provided for illuminating the first object O1 is turned on, and the light emitting element provided for illuminating the second object O2 is turned off. The other luminous elements of the luminous unit 3 which serve to illuminate the surroundings of the objects O1, O2 are controlled unchanged or continue to emit light with the same illumination intensity.

According to an alternative embodiment of the invention, in which the lighting unit 3 is not a high-resolution headlight but a headlight with a low resolution, the objects O1, O2 cannot be blanked, and modified calculation rules are carried out in the calculation unit 10. In accordance with the first variant of the invention, the contrast ratios K1 and K1 'or K2 and K2' of the objects O1, O2 in the on-state and the off-state of the light-emitting unit 3 are calculated. The manipulation signal 14 may have only two states, namely a state "on" when the light emitting unit 3 is turned on and a state "off" when the light emitting unit 3 is turned off. According to the rules by the following possible combinations

K _max ＝max((K1；K2)；(K1’、K2’))

Forming a maximum value K _max : on the one hand the combinations K1, K2 in the case of the light-emitting unit 3 being switched on and on the other hand the combinations K1', K2' in the case of the light-emitting unit 3 being switched off.

If, for example, contrast K1 is high and contrast K2 is low, and contrast K1 'is high (as high as contrast K1) and contrast K2' is greater than contrast K2, steering signal 14 will be determined from contrast K1 'and K2'. This ensures that the two objects O1, O2 are illuminated with a sufficiently high contrast, wherein the objects O1, O2 with poor visibility are also clearly visible.

List of reference numerals

1. Front area of vehicle

2. Vehicle with a vehicle body having a vehicle body support

3. Light-emitting unit

4. Light source

6. 6' detection unit/camera

7. Control unit

8. Road lighting

9. Street lamp

10. Calculation unit

11. Reference database

12. Manipulation database

13. Graph chart

14. Control signal

O1, O2 object

S1-S4 Steps 1 to 4

M3-M6 road illumination grade

K1, K2 first contrast

K1', K2' second contrast

K1 _max 、K2 _max Maximum contrast value

K _max Maximum value

Claims

1. Device for illuminating a front area (1) of a vehicle, the device having:

a lighting unit (3) integrated in the vehicle (2) for producing a predetermined light distribution in the front region (1) of the vehicle,

a detection unit (6) for detecting objects (O1, O2) and/or ambient lighting (8) in the front region (1) of the vehicle,

a control unit (7) for controlling the light-emitting unit (3),

a computing unit (10) for processing and/or analyzing the evaluation data,

the detection means (6) is characterized by comprising, as detection data:

means for detecting the brightness of the object (O1, O2),

means for detecting an ambient illumination (8) of the front area (1) of the vehicle, said ambient illumination being generated by a light source (9) arranged outside the vehicle (2),

the calculation unit (10) has:

means for calculating the current contrast (K1, K2) of the object (O1, O2) from the detection data, and means for calculating the changed contrast (K1 ', K2') of the object (O1, O2) from the illumination state of the object (O1, O2) which can be occupied by the variable actuation of the light-emitting unit (3) and from the ambient illumination (8) of the object (O1, O2),

-means for generating a steering signal (14) for the lighting unit (3) as a function of a comparison of the current contrast (K1, K2) of the object (O1, O2) with the calculated contrast (K1 ', K2') of the object (O1, O2).

2. The device according to claim 1, characterized in that the calculation unit (10) has means for calculating a maximum contrast (K1) from the current contrast (K1, K2) of the object (O1, O2) and the contrast (K1 ', K2') of the object (O1, O2) calculated by variably actuating the light-emitting unit (3) _max 、K2 _max ) Is a device of (a).

3. The device according to claim 1 or 2, characterized in that the computing unit (10) has means for selecting the manipulation signals (14) from a manipulation database (12), in which manipulation database (12) stored manipulation signals (14) for different classes of road lighting parameters (M3, M4, M5, M6) are stored.

4. A device according to any one of claims 1 to 3, characterized in that the control signal (14) for the lighting unit (3) is configured such that only the following lighting elements of the lighting unit (3) are controlled, which illuminate the area of the vehicle front area (1) where the object (O1, O2) is located.

5. The device according to any one of claims 1 to 4, characterized in that the light-emitting unit (3) is configured as a high-resolution headlight with a plurality of individually controllable light-emitting elements.

6. The device according to any one of claims 1 to 5, characterized in that the computing unit (10) has on the one hand means for computing a first contrast (K1, K2) of the object (O1, O2) with the lighting unit (3) switched on, and has means for computing a second contrast (K1 ', K2') of the object (O1, O2) with the lighting unit (3) switched off and/or means for computing a further contrast (K1 ', K2') of the object (O1, O2) in the dimmed on state of the lighting unit (3), the computing unit having means for comparing the first contrast (K1, K2) with the second contrast (K1 ', K2'), if appropriate with the further contrast (K1 ", K2 '), so that a value (K1') of the maximum contrast is used _max 、K2 _max ) The control signal (14) is adapted to control the light-emitting unit (3), and the maximum contrast value is calculated from the first contrast (K1, K2) and the second contrast (K1 ', K2') and optionally further contrast (K1 ', K2').

7. The device according to any one of claims 1 to 6, characterized in that the control signal (14) for controlling the light emitting unit (3) is dependent on the distance of the object (O1, O2) to the device and/or on the reflectivity of the object (O1, O2).

8. The apparatus according to any one of claims 1 to 7, characterized in that the reflectivity of the object (O1, O2) is determined by comparing the brightness data of the object (O1, O2) determined by the detection unit (6) with reference data stored in a reference database (11).

9. The device according to any one of claims 1 to 8, characterized in that the ambient lighting (8) is formed by road lighting (9), the road lighting (9) being classified in the steering database (12) using a plurality of road lighting parameters S (M3, M4, M5, M6) having respectively different lighting intensity ranges.

10. The device according to any one of claims 1 to 9, characterized in that the detection unit (6) has a camera (6') and/or a radar sensor and/or a lidar sensor.

11. Method for operating a lighting unit (3) of a vehicle (2), wherein the lighting unit (3) illuminates a vehicle front area (1) which is additionally illuminated by ambient illumination (8) from another direction, objects (O1, O2) located in the vehicle front area (1) are detected with the position of the objects in the vehicle front area (1) being determined,

the brightness of the object (O1, O2) and the brightness of the surroundings of the object (O1, O2) are determined,

determining the contrast (K1, K2) of the object (O1, O2) by comparing the brightness data of the object (O1, O2) with the surrounding environment or by comparing the ascertained brightness data of the object (O1, O2) with the surrounding environment with reference data,

calculating at least one further contrast (K1 ', K2') of the object (O1, O2) with the light-emitting unit (3) being controlled in a changing manner,

-changing the control signal (14) for controlling the lighting unit (3) if the calculated changed contrast (K1 ', K2') is greater than the current contrast (K1, K2) of the object (O1, O2).

12. The method according to claim 11, characterized in that the object (O1, O2) is determined to be inThe calculated values of the contrasts (K1, K2; K1', K2'; K1', K2') are compared with one another and the highest value of the contrasts (K1, K2; K1', K2'; K1', K2') is considered as the maximum contrast value (K1) when the light-emitting unit (3) is on and when the light-emitting unit (3) is off and/or when the light-emitting unit (3) is dimmed _max 、K2 _max ) For forming a control signal (14) for the lighting unit (3).

13. Method according to claim 11 or 12, characterized in that, depending on the calculated maximum contrast value (K1 _max 、K2 _max ) Only the following light-emitting elements of the light-emitting unit (3) are actuated, by means of which the objects (O1, O2) are illuminated.

14. Method according to any one of claims 11 to 13, characterized in that the reflectivity of the object (O1, O2) is determined by comparing the current brightness value of the object (O1, O2) with reflection data stored in a stored reflection database (11), and the manipulation signal (14) is generated from the reflectivity of the object (O1, O2), from the ambient lighting (8) and from the distance of the object (O1, O2).