Lighting system for a motor vehicle and method for adjusting a light unit of a lighting system

Abstract

Lighting system for a motor vehicle (2) with a control unit, with at least one image acquisition unit (10) which acquires at least one raw image (20), with at least one light unit (12, 13) which has at least one light source (14), wherein the light unit (12, 13) can be adjusted by means of at least one adjusting device (15) and wherein the light unit (12, 13) in the activated state generates a light distribution with light-dark boundaries (16) as part of the raw images (20), HDGs for short, such that an adjustment of the light unit (12, 13) can be carried out by means of a target / actual comparison with HDGs (18) stored in the control unit, wherein means (32, 36) for contrast adjustment are provided in the control unit, characterized in that at least one sub-raw image (22, 24) can be generated in the control unit, wherein first image processing means (26) are provided which perform adaptive contrast adjustment of the at least one sub-raw image (22, 24) such thatthat an adaptively adapted overall raw image (28) can be generated, wherein second image processing means (36) are provided which carry out at least one adaptive edge adjustment with regard to contrast and intensity, such that an adaptively adapted final image can be generated.

Description

[0001] The invention relates to a lighting system for a motor vehicle, comprising a control unit, at least one image capture unit that captures at least one raw image, and at least one lighting unit that has at least one light source. The lighting unit can be adjusted by means of at least one adjusting device, and the lighting unit, in the activated state, generates a light distribution with light-dark boundaries as part of the raw image, or HDGs for short, such that an adjustment of the lighting unit can be carried out by means of a target / actual comparison with HDGs stored in the control unit. The control unit includes means for contrast adjustment. Furthermore, the invention relates to a method for adjusting a lighting unit of such a lighting system.

[0002] Such lighting systems and methods for adjusting a lighting unit of such a lighting system are well known in the prior art. For example, DE 10 2011 109 440 A1 discloses a lighting system in which a so-called cut-off line, or HDG for short, is generated and projected onto a surface to be subsequently captured by an image capture unit. The captured image(s) is then subjected to image processing in a control unit, in particular, a contrast adjustment is performed. The HDG of the adjusted image is then compared with an HDG stored in the control unit in order to then perform an adjustment or calibration of the respective lighting unit if necessary.It should be clear that such a procedure must be carried out safely, taking into account a wide variety of influencing factors, such as ambient luminance / radiance, the irradiance on the image capture unit, and the reflectivity of the projection object. Despite the well-known image adjustment using image processing tools, it may happen that no clear final image can be provided for a target / actual comparison, making adjustment impossible or even impossible to perform correctly.

[0003] Document DE 10 2016 004 259 A1 discloses a parking assistance system for a vehicle, comprising a monitoring unit for detecting an object in the vehicle's surroundings and a lighting system coupled to the monitoring unit for emitting light into the vehicle's surroundings. The monitoring unit is configured to detect the bearing of an object and to control the distribution of the light emitted by the lighting system depending on the detected bearing.

[0004] The object of the invention is therefore to provide a lighting system or a method for adjusting a light unit of such a lighting system, which avoids the above-mentioned disadvantage in a cost-effective and simple manner.

[0005] This object is achieved in that at least one sub-raw image can be generated in the control unit, wherein first image processing means are provided which perform at least one adaptive contrast adjustment of the at least one sub-raw image such that an adaptively adjusted overall raw image can be generated, wherein second image processing means are provided which perform at least one adaptive edge adjustment with regard to contrast and intensity such that an adaptively adjusted final image can be generated. Such a two-stage image processing method can reliably compensate for the above-mentioned negative influencing factors.

[0006] Advantageously, the first image processing means apply the contrast adaptive histogram equalization method. The second image processing means advantageously incorporate an edge filter function. Furthermore, the first image processing means may comprise a noise reduction filter and / or a device for smoothing and edge preservation.

[0007] Furthermore, the object is achieved by a method for adjusting a light unit of such a lighting system, wherein in a first step the HDGs are projected onto a projection surface, in a second step at least one raw image with the HDGs is captured by the image capture unit, in a third step at least one sub-raw image is created, in a fourth step the sub-raw image is subjected to an adaptive contrast adjustment by means of a first image processing step, in a fifth step possibly several sub-raw images are combined to form an adaptively adjusted overall raw image, in a sixth step the adaptively adjusted overall raw image is subjected to an adaptive edge filtering by means of a second image processing step and a final image is generated,In a seventh step, a final image is subjected to a target / actual comparison with HDGs stored in the control unit and, in an eighth step, an adjustment of the light unit is carried out using the adjusting device.

[0008] Advantageously, an adaptive histogram equalization method can be applied in the fourth step for adaptive contrast adjustment, and / or adaptive edge filtering with edge detection, for example, using an OTSU Canny filter method in conjunction with, for example, a Hough transform and a template matching method, can be applied in the sixth step. Furthermore, in the second step, a raw image can be created for each HDG by image separation, thus ensuring reliable assignment to the respective light unit.

[0009] The invention is explained in more detail below with reference to a drawing, in which: Fig. 1 is a schematic view of a motor vehicle in which an adjustment of a light unit of a lighting system is carried out, and Fig. 2 a block diagram of a two-stage image processing of a raw image.

[0010] Fig. 1 shows a vehicle 2 in front of a projection surface 4. The vehicle 2 has a lighting system 6 with a control unit (not shown in detail), with an image capture unit 10 arranged in the front 8 of the motor vehicle 2, and two lighting units 12, 13, each of which has known headlights 14 designed as light sources with integrated adjusting devices 15. It should be noted that the term adjusting device is not limited to a drive mechanism for conventional halogen or xenon headlights. The term adjusting device also includes the adjusting device of an LED matrix beam headlight, in which individual LEDs can be switched on or off or dimmed.

[0011] In the present exemplary embodiment, a projection image with a so-called cut-off line (CDC) 16 is projected onto the projection surface 4 as part of a raw image 20 by the switched-on light source 14. This projected CDC 16 is shown in a solid line. A further cut-off line 18 is shown in a dashed line, which describes the target CDC stored in the control unit. The shift between the actual CDC 16 and the target CDC 18 is to be corrected by adjusting the light unit 12. However, it is particularly important that the actual CDC 16 is optimally captured even under poor ambient conditions.

[0012] This shows Fig. 2 shows a block diagram of a two-stage contrast processing of a raw image 20 captured by the image acquisition unit 10. In the present embodiment, two sub-raw images 22, 24 are generated in the control unit, each of which is subsequently processed by first image processing means 26 into an adaptively adjusted overall raw image 28. The first image processing means 26 comprise a noise suppression filter 30, a device 32 that applies the contrast adaptive histogram equalization method, and a device 34 for smoothing and edge preservation.The adaptively adjusted overall raw image 28 is then adaptively processed in a second image processing stage by second image processing means, here a device 36 which performs an edge filter function, with regard to contrast and intensity, so that an adaptively adjusted final image is created which can be compared in the control unit in a target / actual comparison with the stored HDG 18.

[0013] A method according to the invention for adjusting the light units 12, 13 of the lighting system 6 is now carried out as described below. In a first step, the HDGs 16 are projected onto a projection surface 4. In the present case, Fig.1, for the sake of clarity, only the HDG 16 of the light unit 12 is shown. In a second step, at least one raw image 20 with the HDGs 16 is captured by the image capture unit 10, wherein it is particularly advantageous if a raw image 20 is created for each HDG, for example by image separation. Subsequently, in a third step, two sub-raw images 22, 24 are created. In a fourth step, these sub-raw images 22, 24 are then subjected to a first image processing by means of first image processing means 26. In this case, in particular, the means 30, 32, 34 perform noise suppression, adaptive contrast adjustment, smoothing, and edge preservation of the sub-raw images 22, 24. In a fifth step, the processed sub-raw images 22, 24 are then combined to form an adaptively adjusted overall raw image 28.Subsequently, in a sixth step, the adaptively adjusted overall raw image 28 is subjected to adaptive edge filtering with edge detection, here an OTSU-Canny filter method in conjunction with, for example, a Hough transformation and a template matching method, using a second image processing method, and a final image is generated. This enables, in particular, reproducible HDG detection, whereby false structures can be excluded. In a seventh step, the final image is then compared with a target / actual comparison of HDGs 18 stored in the control unit, in order to then, in an eighth step, perform an adjustment of the light unit 12, 13 using the adjusting device 15. It should be noted here that, for the sake of clarity, the description of the method according to the invention has referred to the adjustment of a light unit, here the light unit 12.It should also be clear that a large number of sub-raw images can be created to ensure greater accuracy in the evaluation.

Claims

[1] Lighting system for a motor vehicle (2) with a control unit, with at least one image acquisition unit (10) which acquires at least one raw image (20), with at least one light unit (12, 13) which has at least one light source (14), wherein the light unit (12, 13) is adjustable by means of at least one adjusting device (15) and wherein the light unit (12, 13) in the activated state generates a light distribution with light-dark boundaries (16) as part of the raw images (20), HDGs for short, such that an adjustment of the light unit (12, 13) can be carried out by means of a target / actual comparison with HDGs (18) stored in the control unit, wherein means (32, 36) for contrast adjustment are provided in the control unit, characterized bythat at least one sub-raw image (22, 24) can be generated in the control unit, wherein first image processing means (26) are provided which carry out at least one adaptive contrast adjustment of the at least one sub-raw image (22, 24) in such a way that an adaptively adjusted overall raw image (28) can be generated, wherein second image processing means (36) are provided which carry out at least one adaptive edge adjustment with regard to contrast and intensity in such a way that an adaptively adjusted final image can be generated. [2] Lighting system according to claim 1, characterized by that the first image processing means (26) apply the contrast adaptive histogram equalization method. [3] Lighting system according to claim 1 or 2, characterized by that the second image processing means (36) has an edge filter function. [4] Lighting system according to one of the preceding claims, characterized bythat the first image processing means (26) comprise a noise suppression filter (30) and / or means (34) for smoothing and edge preservation. [5] Method for adjusting a light unit (12, 13) of a lighting system (6) according to one of the preceding claims, characterized bythat in a first step the HDGs (16) are projected onto a projection surface (4), that in a second step at least one raw image (20) with the HDGs (16) is captured by the image capture unit (10), that in a third step at least one sub-raw image (22, 24) is created, that in a fourth step the sub-raw image (22, 24) is subjected to an adaptive contrast adjustment by means of a first image processing step, that in a fifth step, if necessary, several sub-raw images (22, 24) are combined to form an adaptively adjusted overall raw image (28), that in a sixth step the adaptively adjusted overall raw image is subjected to adaptive edge filtering by means of a second image processing step and a final image is generated, that in a seventh step a final image is subjected to a target / actual comparison with HDGs stored in a control unit and that in an eighth step an adjustment of the light unit (12,13) is carried out by means of an adjusting device (15)., [6] Method for adjusting a light unit (12, 13) of a lighting system (6) according to claim 5, characterized by that in the fourth step an adaptive histogram equalization method is used for adaptive contrast adjustment. [7] Method for adjusting a light unit (12, 13) of a lighting system (6) according to claim 5 or 6, characterized by that in the sixth step, adaptive edge filtering with edge detection, for example by an OTSU Canny filter method in conjunction with, for example, a Hough transform and a template matching method, is applied. [8] Method for adjusting a light unit (12, 13) according to one of claims 5-7, characterized by that in the second step a raw image (20) is created for each HDG by image separation.

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