Vehicle lighting system

Abstract

Vehicle lighting system (2) comprising: a camera (10) configured to capture an image of an area in front of a vehicle to generate image information (S1), a control device (12) configured to generate a light distribution command (S2) for instructing the formation of a light distribution pattern (S REF ) in the area in front of the vehicle based on the image information (S1) from the camera (10), a headlight (14) configured to illuminate the area in front of the vehicle such that the commanded light distribution pattern (S REF ) is obtained based on the light distribution command (S2), and a position calibrator (20) configured to detect a position deviation between the camera (10) and the headlight (14), wherein the position calibrator (20) is configured to perform the following steps: Detecting a reference object (30) on a road based on the image information (S1), and measuring the brightness (S4) of the reference object (30), and when a certain difference between a light distribution pattern (S CALA ) brightness obtained (S4 A ) of the reference object (30) and one consisting of a different light distribution pattern (S CALB ), in which a quantity of light of only one part is different from the one light distribution pattern (S CALA ), obtained brightness (S4 B ) of the reference object (30), detecting the position deviation using the position of the part.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2015-049563 filed on March 12, 2015, the contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present invention relates to a vehicle lighting system used in a car or the like. BACKGROUND

[0003] Generally, a vehicle lamp is configured to alternate between a low beam and a high beam. The low beam is used to illuminate a nearby area with a predetermined luminosity. The light distribution is controlled so as not to dazzle oncoming and preceding vehicles. The low beam is used primarily while driving in an urban environment. In contrast, the high beam is used to illuminate a wider and farther area with a relatively high luminosity and is used primarily while driving at high speed on a road with few oncoming and preceding vehicles. The high beam provides better visibility for the driver compared to the low beam, but can dazzle the driver of another vehicle or a pedestrian in front of the vehicle.In the past, vehicle lighting systems and headlight technologies have therefore been developed that use adaptive matrix LED lighting systems, as described in DE 10 2012 007 908 A1 and DE 10 2015 203 889 A1.

[0004] In recent years, ADB (Adaptive Driving Beam) technology has been proposed for dynamically and adaptively controlling the light distribution pattern of the high beam based on a vehicle's environmental conditions. ADB technology is used to detect whether a preceding vehicle, an oncoming vehicle, or a pedestrian is in front of the vehicle and to reduce the illumination in an area corresponding to the vehicle or pedestrian, thereby reducing glare caused to the vehicle or pedestrian.

[0005] Fig. 1 is a basic block diagram of a vehicle lighting system using an ADB. A vehicle lighting system (also simply referred to as a lighting system) 2r includes a camera 10, a controller 12, and a headlight (high beam) 14. The camera 10 is configured to capture an image of an area in front of the vehicle. The controller 12 is configured to detect a preceding vehicle, an oncoming vehicle, a pedestrian, and the like based on image information S1 obtained by the camera 10, and to generate a light distribution pattern including a light-ON area R. ON in which the beam is to be emitted and a light-OFF area R OFFin which the beam should not be irradiated. The control device 12 is configured to generate a light distribution command S2 for instructing the light distribution pattern and supply it to the headlight 14. The headlight 14 is configured to illuminate an area in front of the vehicle based on the light distribution command S2 generated by the control device 12, so that a desired light distribution pattern is obtained (see, for example, JP-A-2013-147138).

[0006] In the 2r lighting system from Fig. 1, the precision of the mounting position of the camera 10 and the spotlight 14 may be important. If the two mounting positions differ from each other, an area where the light should actually be shielded will be illuminated, causing glare.

[0007] For this reason, the state of the art uses the light-OFF range R OFFset in such a way that a possible deviation of the mounting positions of the camera 10 and the headlight 14 is taken into account. In particular, when a preceding vehicle or an oncoming vehicle is detected from an image of the camera 10, an area defined by adding an edge to an area R x in which the preceding vehicle or the oncoming vehicle is present is set as the light-off area so that glare is prevented.

[0008] Incidentally, a method for controlling the light distribution pattern by the headlight 14 includes (1) a splitting method for dividing an illumination area into a plurality of small areas and alternating light-ON and light-OFF in each small area; (2) a scanning method for scanning a beam to an area in front of the vehicle and alternating light-ON and light-OFF every predetermined time; and so on. The headlight 14 to be used for the ADB system is designed to control the light distribution with greater precision. For example, in the splitting method, the number of splits is increased to perform high-precision light distribution control, and in the scanning method, the time resolution of the light-ON / light-OFF switching is increased to perform high-precision light distribution control.

[0009] If the control device 12 determines the light distribution pattern by taking a wide margin of the light-OFF range to account for the positional deviation, the advantage of the high-precision headlight 14 is lost, so that the headlight 14 has too high and unused quality. SUMMARY

[0010] The present invention takes into account the above-described circumstances, and an object of the present invention is to provide a vehicle lamp system that can detect a positional deviation between a camera and a headlight.

[0011] According to the present invention, there is provided a vehicle lighting system comprising: a camera configured to capture an image of an area in front of a vehicle to generate image information; a controller configured to generate a light distribution command for instructing the formation of a light distribution pattern in the area in front of the vehicle based on the image information from the camera; a headlight configured to illuminate the area in front of the vehicle such that the instructed light distribution pattern is obtained based on the light distribution command; and a position calibrator configured to detect a position deviation between the camera and the headlight.The position calibrator is configured to perform the following steps: detecting a reference object on a road based on the image information, and measuring the brightness of the reference object; and when there is a certain difference between a brightness of the reference object obtained from one light distribution pattern and a brightness of the reference object obtained from another light distribution pattern in which a light amount of only one part is different from the one light distribution pattern, detecting the position deviation using the position of the part.

[0012] A luminaire coordinate system may be defined for a spotlight, and a camera coordinate system may be defined for a camera. In this case, when the brightness of a reference object obtained from the camera is determined when the light quantity of a part of the luminaire coordinate system is changed by the spotlight, the coordinates of the reference object in the camera coordinate system and the coordinates of the part of the luminaire coordinate system where the light quantity has changed can be associated. Thus, according to the above configuration, the positional deviation between the camera and the spotlight can be detected and calibrated as needed.

[0013] A “certain difference in brightness” means a brightness difference that can be recognized as a brightness change due to a change in the light distribution pattern, and not a brightness difference caused by ambient light or noise.

[0014] In the vehicle lamp system, the position calibrator may include: a reference object detector configured to detect the reference object based on the image information and generate brightness data indicating the brightness of the reference object; a pattern generator configured to generate a light distribution command for instructing a switchable light distribution pattern for calibration; and a position deviation detector configured to determine whether a certain difference exists between the brightness data obtained from one light distribution pattern and the brightness data obtained from the other light distribution pattern, and generate calibration data in accordance with the determination result.

[0015] In the vehicle lighting system, the position calibrator can be configured to perform the following steps: (i) providing, for the headlamp, a first light distribution command for commanding the one light distribution pattern; (ii) obtaining a brightness of the reference object from first image information obtained when the area in front of the vehicle is illuminated in accordance with the first light distribution command; (iii) setting a second light distribution command for instructing the other light distribution pattern and providing it to the headlamp; (iv) obtaining a brightness of the reference object from second image information obtained when the area in front of the vehicle is illuminated in accordance with the second light distribution command; (v) detecting a difference between the brightness of the reference object obtained from the first image information and the brightness of the reference object obtained from the second image information; (vi) when a certain brightness difference is detected in (v), detecting a position deviation amount; and (vii) if the determined brightness difference in (v) is not detected, returning to (iii) and updating the other light distribution pattern while shifting the part.

[0016] By repeating the steps, the part where the brightness of the object can be changed can be captured.

[0017] In the vehicle lighting system, the part in (iii) may be a position of the reference object for the first time. When the determined brightness difference in (vi) is detected for the first time, it can be determined that the positions of the camera and the headlight are correct.

[0018] In the vehicle lighting system in (iii), the part may be gradually removed from a position of the reference object with each update.

[0019] In the vehicle lighting system, the reference object may be a predetermined sign, a beacon, and / or a road image drawn on a road surface.

[0020] In the vehicle lighting system, the reference object may be a preceding vehicle.

[0021] According to an aspect not belonging to the present invention, there may alternatively be provided a vehicle lighting system comprising: a camera configured to capture an image of an area in front of a vehicle to generate image information; a controller configured to generate a light distribution command for instructing the formation of a light distribution pattern in the area in front of the vehicle based on the image information from the camera; a headlight configured to illuminate the area in front of the vehicle such that the instructed light distribution pattern is obtained based on the light distribution command; a marker generator fixed with respect to the headlight and configured to illuminate a predetermined area in front of the vehicle with a marker;and a position calibrator configured to detect a position deviation between the camera and the headlight based on the position of the marker appearing in the image information when the marker generator illuminates the area in front of the vehicle with the marker.;

[0022] Because the marker is fixed relative to the headlight, illumination at predetermined coordinates of the luminaire coordinate system is guaranteed. Therefore, the marker coordinates of the camera coordinate system obtained from the image information and the predetermined coordinates of the luminaire coordinate system can be associated with each other. Therefore, according to this aspect, the positional deviation between the camera coordinate system and the luminaire coordinate system can be detected and calibrated as needed.

[0023] Incidentally, any combination of the above-mentioned conventional components and the replacements of the conventional components and expressions of the present invention can be used in a method, apparatus, system or the like according to aspects of the present invention.

[0024] According to the configuration described above, a position deviation between the camera and the headlight can be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other aspects of the present invention will become more apparent from the following description of exemplary embodiments of the present invention with reference to the accompanying drawings. Fig. 1 is a basic block diagram of a vehicle lighting system using an ADB. Fig. 2 is a block diagram showing a lighting system according to an exemplary embodiment of the invention. Fig. 3 shows an area in front of a vehicle. Fig. Figure 4 is a functional block diagram showing a configuration example of a position calibrator. Fig. 5 is a first flowchart of calibration processing. Fig. 6 is a second flowchart of calibration processing. Fig. 7 shows the transition of a light distribution pattern corresponding to the flow chart of Fig. 5. Fig. Figure 8 shows the transition of a light distribution pattern corresponding to the flow chart of Fig. 6. Fig. 9A to 9D show a calibration using a preceding vehicle as a reference object. Fig. 10 is a block diagram showing a lighting system according to an exemplary alternative, but not part of the invention. Fig. 11 shows an area in front of a vehicle. Fig. Figure 12 is a functional block diagram showing a configuration example of a position calibrator. DETAILED DESCRIPTION

[0026] The exemplary embodiment of the present invention and the alternative not belonging to the invention are described below with reference to the drawings. Identical or equivalent components are designated by the same reference numerals in the corresponding drawings, and a repeated description thereof is omitted. The embodiment shown is not to be understood as restrictive but as an example, and the features and combinations thereof mentioned in the exemplary embodiments are not necessarily essential to the present invention. (Exemplary embodiment of the invention)

[0027] Fig. Figure 2 is a block diagram showing a lighting system 2 according to the exemplary embodiment of the invention. The lighting system 2 has an ADB function and is configured to form various light distribution patterns in an area in front of a vehicle.

[0028] The lighting system 2 comprises a camera 10, a control device 12, a headlight 14 and a position calibrator 20. The headlight 14 has a high beam with the ADB function.

[0029] The camera 10 is configured to capture an image of an area in front of the vehicle to generate image information S1. The controller 12 is configured to generate a light distribution command S2 for instructing the formation of a target light distribution pattern S REFin the area in front of the vehicle based on the image information S1 from the camera 10. The light distribution pattern is configured by a combination of a light-off area into which no light is to be irradiated and a light-on area into which light is to be irradiated. The light amount of the light-on area can be varied. For example, the controller 12 is configured to detect a preceding vehicle, an oncoming vehicle, a pedestrian, or the like based on the image information S1 and set an area in which the object is detected as the light-off area so as not to cause glare, or set the area as the light-on area with a very small amount of light.Vehicle speed information and steering information may be input to the control device 12, and the control device 12 may be configured to include the additional information in the target light distribution pattern S. REF to be taken into account.

[0030] The control device 12 may be configured by a combination of hardware, such as a central processing unit (CPU), a microcontroller, or the like, and software. The control device 12 may be part of an electronic control unit (ECU) for a lamp embedded in a vehicle lamp (lamp assembly) or part of an ECU for a vehicle mounted in a vehicle.

[0031] The headlight 14 is configured to illuminate the area in front of the vehicle based on the light distribution command S2 such that the target light distribution pattern S REFis obtained. The light distribution pattern actually generated in the area in front of the vehicle by the headlight 14 based on the vehicle information S2 is referred to as an illumination pattern I.

[0032] If there is no positional deviation between the camera 10 and the headlight 14, the illumination pattern I coincides with the target light distribution pattern S REF If, however, the mounting positions of the camera 10 and the spotlight 14 differ, the illumination pattern I will be different from the target light distribution pattern S REF .

[0033] The lighting system 2 from Fig. 2 includes the position calibrator 20 configured to detect a deviation between the mounting positions of the camera 10 and the headlight 14. A method for detecting the position deviation by the position calibrator 20 will be described below.

[0034] The position calibrator 20 is configured to detect the position deviation through the following steps.

[0035] (Step 1) The position calibrator 20 is configured to detect a reference object on a road based on the image information S1 and measure the brightness of the reference object.

[0036] The reference object may be a road sign, a beacon, a stop line, or a road image drawn on a road surface. Alternatively, as described below, a vehicle may be used as the reference object. The reference object is preferably an object that has a property that reflects the light emitted by the headlight 14 and is not a light-emitting object. The position calibrator 20 may be configured to detect the reference object using information from a vehicle navigation system.

[0037] For simplicity, it is assumed below that the reference object is a road sign having a predetermined shape and color and on which a predetermined letter or symbol is drawn. The position calibrator 20 is configured to refer to the image information S1, detect the reference object in an image by pattern matching, and specify coordinates of the reference object.

[0038] (Step 2) If a certain (significant) difference between a brightness L obtained from the light distribution pattern REF of the reference object and a brightness of the reference object obtained from another light distribution pattern in which the light quantity of only a part (referred to as attention area) is different from the one light distribution pattern, the positional deviation is detected using the position of the part (attention area).

[0039] The basic configuration of the lighting system 2 according to the exemplary embodiment of the invention has been described above. The processing for detecting the position deviation (calibration) will be described below.

[0040] Fig. 3 shows an area in front of the vehicle.

[0041] In this example, the headlight 14 is configured to perform ADB control using the division method. Specifically, the illumination area is divided into eleven small areas Rs1 to Rs11, and the headlight 14 is configured to alternate light ON and light OFF for each small area Rs. The positions of the small areas Rs1 to Rs11 are adjusted depending on the mounting position of the headlight 14.

[0042] To simplify the understanding, a camera coordinate system θ CAM, which is based on the mounting position of the camera 10, and a luminaire coordinate system θ LAMP , which is based on the mounting position of the headlight 14. In the first exemplary embodiment, it is assumed that each coordinate system has an angular dimension. If the mounting position of the camera 10 and the mounting position of the headlight 14 are correct, the origins of the coordinate systems θ CAM , θ LAMP together as described in Part A of Fig. 3 shown.

[0043] If a position deviation occurs between the camera 10 and the headlight 14, the origins of the coordinate systems θ CAM , θ LAMP not aligned with each other, as shown in Part B of Fig. 3. Only a case in which the headlight 14 is not aligned is shown here. However, the position deviation can occur for both the camera 10 and the headlight 14.

[0044] The control device 12 is configured to generate a light distribution command S2 based on the image information S1 generated by the camera 10. The light distribution command S2 is thus generated based on the camera coordinate system θ CAM Furthermore, the headlight 14 is configured to determine the area in front of the vehicle based on the light coordinate system θ LAMP to illuminate, assuming that the camera coordinate system θ CAM and the luminaire coordinate system θ LAMP coincide with each other.

[0045] ADB control during normal travel is described in the case where the coordinate systems are not aligned as shown in Part B. If, as in Fig. 3 shows an oncoming vehicle 32 between the coordinates [θ L1 to θ R1 ] (the small areas Rs6, Rs7) in the camera coordinate system θ CAM is detected, the control device 12 generates a light distribution pattern in which a range of the coordinates [θ L1 to θ R1 ] is set as the light-OFF area. The headlight 14 illuminates the area in front of the vehicle, with the coordinates [θ L1 to θ R1] of the luminaire coordinate system θ LAMP be considered as the light-OFF area. This means that the small areas Rs8, Rs9 are the light-OFF area R OFF and the small areas Rs6, Rs7 of the light-ON area R ON so as to cause dazzling of the oncoming vehicle 32.

[0046] The following describes a calibration process for solving this problem. Based on the image information S1 from the camera 10, a stop sign is selected as the reference object 30 within a range of [θ L2 to θ R2 ] of the camera coordinate system θ CAM For simplicity, it is assumed that the vehicle is stationary and the field of view in front of the vehicle does not change during calibration.

[0047] The position calibrator 20 switches between at least two light distribution patterns, allowing the headlight 14 to illuminate the area in front of the vehicle for calibration. In one light distribution pattern and another light distribution pattern, the light quantity of only the part (the attention area) θx to θy is different, and the light quantities of the other parts are the same.

[0048] For example, one light distribution pattern is set such that all areas are light-ON. The other light distribution pattern is set such that only the area from [θx to θy] is light-OFF, and the other areas are light-ON. It is assumed that when the two light distribution patterns are switched, the brightness of the reference object 30 changes. In this case, it can be said that the coordinates [θ L2 to θ R2 ] of the camera coordinate system θ CAM the coordinates [θx to θy] of the luminaire coordinate system θ LAMP Therefore, if the coordinates of a left end are taken as a reference, the deviation amount between the camera coordinate system θ CAM and the luminaire coordinate system θ LAMP equal to [θ L2- θx]. Regarding the coordinates, any reference can be used. For example, if the coordinates of a right end are used as a reference, the deviation quantity [θ R2 - θy]. Alternatively, a reference can be taken at a center. The following describes a case in which the left end is taken as a reference.

[0049] In other words, the calibration to be performed by the position calibrator 20 corresponds to the detection of the attention range [θx to θy] in which the brightness of the reference object 30 can be changed.

[0050] Here we will consider the example of a case where there is no positional deviation (see part A of Fig. 3). In this case, if the attention range [θx to θy] is set to [θ L2 to θ R2 ] is set, a brightness change of the reference object 30 is detected. Because the deviation quantity θ L2 - θx = θL2 - θ L2 = 0, it can be confirmed that there is no position deviation.

[0051] Furthermore, a case shall be considered in which a positional deviation is given (see part B of Fig. 3). In this case, if the attention range [θx to θy] is set to [θ L2 - Δθ to θ R2 - Δθ] is set, the brightness change of the reference object 30 is detected. Because the deviation quantity θ L2 - θx = θ L2 - (θ L2 - Δθ) = Δθ, it coincides with the deviation quantity Δθ ​​of the coordinate system.

[0052] In this way, in the lighting system 2 of Fig. 2 the position deviation between the camera 10 and the headlight 14 can be recorded and calibration can be carried out if necessary.

[0053] No particular restrictions are imposed on the calibration method here. For example, when the control device 12 generates the light distribution command S2, angle information in which the deviation amount Δθ has been corrected may be provided. Alternatively, the deviation amount Δθ may be maintained for the headlight 14, and the angle information specified by the light distribution command S2 may be shifted taking the deviation amount Δθ into account.

[0054] The configuration of the position calibrator 20 and a calibration procedure are described in detail below. Incidentally, the present invention encompasses various aspects apparent from the above description and is not limited to the specific examples described below.

[0055] Fig. Figure 4 is a functional block diagram showing a configuration example of the position calibrator 20. The position calibrator 20 includes a reference object detector 22, a pattern generator 24, and a position deviation detector 26.

[0056] The position calibrator 20, like the controller 12, may be configured using a combination of hardware such as a central processing unit (CPU), a microcontroller, or the like, and software. The position calibrator 20 may be part of an electronic control unit (ECU) for a lamp embedded in a vehicle lamp (lamp assembly) or part of an ECU for a vehicle mounted in a vehicle. The controller 12 and the position calibrator 20 may be the same processor or CPU.

[0057] The reference object detector 22 is configured to detect the reference object 30 by pattern matching based on the image information S1 from the camera 10 and to generate brightness data S4 indicating the brightness of the reference object 30. The reference object detector 22 may be configured to generate position data S5 indicating a position [θ L2 to θ R2 ] of the reference object 30 in the camera coordinate system.

[0058] The pattern generator 24 is configured to generate a light distribution command S3 for instructing a changeable light distribution pattern for calibration. During calibration, the headlight 14 is controlled by the light distribution command S3.

[0059] The position deviation detector 26 is configured to determine whether a certain (significant) difference exists between the values ​​obtained from a light distribution pattern S CALA obtained brightness data S4 Aand the one from a different light distribution pattern S CALB obtained brightness data S4 B is present. Furthermore, the position deviation detector 26 is configured to generate calibration data S6 according to the determination result.

[0060] If a driver or pedestrian in the vicinity should not notice the calibration, the light distribution pattern must be changed within a short period of time. In this case, the calibration can be performed in the background, usually by changing the one light distribution pattern S CALA is output and for a short period of time to the other light distribution pattern S CALB In this case, if the image information S1 B for use in generating the brightness data S4 B are generated, the exposure time and the exposure sequence of the camera 10 must be taken into account.

[0061] The position deviation detector 26 is configured to detect a range [θx to θy] in which the brightness of the light distribution pattern S CALA and the brightness of the light distribution pattern S CALB are different. The position deviation detector 26 may be configured to generate the calibration data S6 that calculates the deviation amount Δθ based on a relationship between the range [θx to θy] in which the particular (significant) brightness change is detected and a position [θ L2 to θ R2 ] indicate.

[0062] The position calibrator 20 is configured to provide a combination of the light distribution pattern S CALA and the other light distribution pattern S CALB until the specific (significant) brightness change is detected by the position deviation detector 26.

[0063] With the configuration of the position calibrator 20, it is possible to detect whether a position deviation exists and to determine the deviation quantity Δθ.

[0064] Fig. Figure 5 is a first flowchart of calibration processing.

[0065] First, the light distribution pattern S CALA set (S100) and the brightness data S4 A measured at this time (S102). The light distribution pattern S CALA can be any pattern, such as a pattern that is light-ON in all areas or a pattern that is light-OFF in all areas. Alternatively, during calibration while driving, the target light distribution pattern S generated immediately before by the control device 12 REF be used.

[0066] Then the other light distribution pattern S CALB set (S104) and the brightness data S4 Bmeasured at this time (S106). As described above, the light distribution pattern S CALB and the light distribution pattern S CALA a relationship in which the light quantities only of the attention area [θx to θy] are different.

[0067] If the absolute value |S4 A - S4 B | the brightness difference is greater than a predetermined threshold S TH is (YES in S108), that is, when a certain (significant) brightness difference is detected, the position deviation amount is calculated based on the attention range [θx to θy] at that time (S110).

[0068] If the brightness difference |S4 A - S4 B | smaller than the threshold S THis (NO in S108), ie, if no specific (significant) brightness difference is detected, the processing returns to step S104 and the attention area [θx to θy] is changed to obtain the light distribution pattern S CALB to update.

[0069] The position deviation amount can be detected using the procedure described above.

[0070] Fig. Figure 6 is a second flowchart of the calibration processing. In the flowchart of Fig. 5 is the light distribution pattern S CALA fixed to the initial state set the first time and only the light distribution pattern S CALB In contrast to the flowchart of Fig. 6 the light distribution pattern S CALB of a cycle as the reference light distribution pattern S CALA of a next cycle.

[0071] In particular, step S112 is added. If it is determined in step S108 that the brightness difference |S44 - S4 B | smaller than the threshold S TH is (NO in S108), ie if no specific (significant) brightness difference is detected, the preceding light distribution pattern S CALB for comparison as the reference light distribution pattern S CALA set and the preceding brightness data S4 B for comparison as the reference brightness data S4 A In step S104, the light distribution pattern S CALB updated.

[0072] Through this process, the position deviation amount can be detected. Especially when the calibration is performed during driving, it can be said that the process of Fig. 6 is more advantageous.

[0073] The following describes an algorithm for generating the light distribution command S3 for calibration by the pattern generator 24, ie, the processing of step S104 of Fig. 5 or Fig. 6 described.

[0074] The pattern generator 24 may be configured to shift the attention area [θx to θy] so as to gradually move from the coordinates [θ L2 to θ R2 ] (the initial value) of the reference object 30 is removed.

[0075] Fig. 7 shows the transition of the light distribution pattern S CALB in accordance with the flow chart of Fig. 5. The attention area [θx to θy] is shifted to gradually move from the coordinates [θ L2 to θ R2] (the initial value) to be removed. In Fig. 7 the attention area moves in a zigzag shape, but it can also move in a different pattern.

[0076] Fig. 8 shows the transition of the light distribution pattern S CALB in accordance with the flow chart of Fig. 6. The attention area [θx to θy] is shifted to gradually move from the coordinates [θ L2 to θ R2 ] (the initial value) to be removed.

[0077] If the flowchart of Fig. 5 is used, the light distribution pattern S CAL2 at two positions in one cycle and an adjacent cycle as in Fig. 7 shown differently. However, if the flow chart of Fig. 6 is used, the light distribution pattern S CAL2 only at one position in a cycle and an adjacent cycle as in Fig. 8, which is difficult for a driver or a pedestrian in the surrounding area to notice. Therefore, if the calibration is performed in the background, it can be said that the flowchart of Fig. 6 is more advantageous. (Modified Embodiment 1)

[0078] In the embodiment described above, a stop sign, a road image, or a beacon is used as the reference object 30. When calibration is performed in the background while driving, a stationary object in the image information S1 moves, so it is necessary to re-detect the position of the reference object 30 from time to time.

[0079] During calibration while driving, it is preferable to set an object with a low speed relative to the host vehicle as the reference object. While driving on a highway or expressway, the preceding vehicle and the host vehicle often travel at substantially the same speed. Therefore, in this modified embodiment, a preceding vehicle 34 is used as the reference object 30.

[0080] When the preceding vehicle 34 is used as the reference object 30, care must be taken to ensure that no glare is caused during calibration.

[0081] Fig. 9A to 9D show the calibration in which the preceding vehicle is used as the reference object 30. During night driving, the preceding vehicle 34 is detected by the image of the camera 10, and the control device 12 determines the target light distribution pattern S REF such that no dazzling of the vehicle 34 in front is caused. The headlight 14 illuminates the area in front of the vehicle such that the target light distribution pattern S REF is received.

[0082] The light distribution pattern S CAL2 based on the flowchart of Fig. 6. The area [θx to θy] of the attention area 36 gradually moves in a direction closer to the preceding vehicle 34 from both sides of the preceding vehicle 34. In Fig. 9D, the attention area 36 overlaps with the preceding vehicle 34 and the brightness change of the reference object 30 is observed.

[0083] According to this modified embodiment, no glare is caused to the preceding vehicle and calibration can be performed while driving. (Modified Embodiment 2)

[0084] Although the preceding vehicle 34 is used as the reference object 30, glare is not caused if the time period for which the light is irradiated to the reference object 30 is set shorter than a time period perceivable by the driver. Therefore, the same calibration as for the stationary object can be performed. (Alternative not part of the invention)

[0085] Fig. Fig. 10 is a block diagram showing a lighting system 2a according to an alternative not belonging to the invention. The lighting system 2a further comprises a marker generator 16 in addition to the lighting system 2 of Fig. 2.

[0086] The marker generator 16 is fixed with respect to the headlight 14 and configured to emit a marker 40 having a predetermined color and shape toward a predetermined area in front of the vehicle in response to a light emission command S7 from a position calibrator 20a. The marker 40 is emitted toward a position that can be detected by the camera 10. The marker generator 16 is preferably a light source configured to generate light with high directionality, for example, an LED, a laser, or the like.

[0087] The position calibrator 20a is configured to detect a relative position deviation between the camera 10 and the headlight 14 based on the position of the mark 40 that appears in the image information S1 when the mark generator 16 irradiates the mark 40 in the area in front of the vehicle.

[0088] Fig. 11 shows an area in front of the vehicle. Because the marker generator 16 is fixed to the headlight 14, the coordinates of the marker 40 always have a constant value θ M in the luminaire coordinate system θ LAMP regardless of the position deviation of the headlight 14.

[0089] If, as in Part A of Fig. 11, there is no position deviation, the coordinates θ calculated from the image information S1 A the mark 40 in the luminaire coordinate system θ LAMP with θ M together.

[0090] If, as in Part B of Fig. 11, the two coordinate systems differ due to a position deviation of Δθ, the coordinates calculated from the image information S1 are θ A ' of the mark 40' in the luminaire coordinate system θ LAMP equal to θ M + Δθ. This means that the difference between the coordinates θ calculated from the image information S1 A and the coordinates θ M the mark 40 in the luminaire coordinate system θ LAMP which indicates the deviation Δθ between the two coordinate systems.

[0091] In this way, in the lighting system 2a of Fig. 10 the position deviation between the camera 10 and the headlight 14 can be recorded and calibrated if necessary.

[0092] The configuration of the position calibrator 20a will be described in detail below. However, it will be apparent from the above description that the present invention encompasses various aspects and is not limited to the specific examples described below.

[0093] Fig. Figure 12 is a functional block diagram showing a configuration example of the position calibrator 20a. The position calibrator 20a includes a mark detector 42, a position deviation detector 44, and a calibration controller 46.

[0094] Like the controller 12, the position calibrator 20a may be configured using a combination of hardware, such as a central processing unit (CPU), a microcontroller, or the like, and software. The position calibrator 20a may be part of an electronic control unit (ECU) for a lamp embedded in a vehicle lamp (lamp assembly) or part of an ECU for a vehicle mounted in a vehicle. The controller 12 and the position calibrator 20a may be the same processor or CPU.

[0095] The calibration controller 46 is configured to issue the light emission command S7 and turn on the marker generator 16. The light emission timing of the light emission command S7 is synchronized with the exposure time of the camera 10.

[0096] The mark detector 42 is configured to detect the mark 40 by pattern matching based on the image information S1 from the camera 10, position data S8 indicating the position θ A of the mark 40 in the camera coordinate system, and output them to the position deviation detector 44.

[0097] The position deviation detector 44 is configured to generate the calibration data S6 based on a relationship between the coordinates θ detected when the light emission command S7 is issued. A the mark 40 and the reference position θ M to create the mark 40.

[0098] The present invention has been described above with reference to the exemplary embodiment of the invention. The described embodiment is merely exemplary. Combinations of the corresponding components or the corresponding processing steps can be modified in various ways, and the modified embodiments are also included within the scope of the invention. Further modified embodiments are described below.

[0099] In the embodiments described above, ADB control based on a splitting method was described. However, the headlight 14 may also be configured to vary the light distribution pattern using a scanning method or another method.

[0100] Typically, it is the high beam whose light distribution pattern is controlled by the ADB controller. However, the present invention is not limited to this. For example, the present invention can also be applied to a headlight 14 in which the light distribution pattern of the low beam is variable.

[0101] The present invention has been described using various exemplary embodiments, but these exemplary embodiments are merely intended to illustrate the principle and applications of the present invention. Thus, the exemplary embodiments described herein may be modified in various ways without departing from the scope of the invention as defined by the claims.

Claims

[1] Vehicle lighting system (2) comprising: a camera (10) configured to capture an image of an area in front of a vehicle to generate image information (S1), a control device (12) configured to generate a light distribution command (S2) for instructing the formation of a light distribution pattern (S REF ) in the area in front of the vehicle based on the image information (S1) from the camera (10), a headlight (14) configured to illuminate the area in front of the vehicle such that the commanded light distribution pattern (S REF ) is obtained based on the light distribution command (S2), and a position calibrator (20) configured to detect a position deviation between the camera (10) and the headlight (14), wherein the position calibrator (20) is configured to perform the following steps: Detecting a reference object (30) on a road based on the image information (S1), and measuring the brightness (S4) of the reference object (30), and when a certain difference between a light distribution pattern (S CALA ) brightness obtained (S4 A ) of the reference object (30) and one consisting of a different light distribution pattern (S CALB ), in which a quantity of light of only one part is different from the one light distribution pattern (S CALA ), obtained brightness (S4 B ) of the reference object (30), detecting the position deviation using the position of the part. [2] Vehicle lighting system (2) according to claim 1, wherein the position calibrator (20) comprises: a reference object detector (22) configured to detect the reference object (30) based on the image information (S1) and to generate brightness data (S4) indicating the brightness of the reference object (30), a pattern generator (24) configured to generate a light distribution command (S3) for instructing a changeable light distribution pattern for calibration, and a position deviation detector (26) configured to determine whether a certain difference between the light distribution patterns (S CALA ) brightness data obtained (S4 A ) and the other light distribution pattern (S CALB ) brightness data obtained (S4 B ) is present, and for generating calibration data (S6) in accordance with the determination result. [3] Vehicle lighting system (2) according to claim 1 or 2, wherein the position calibrator (20) is configured to perform the following steps: (i) providing, for the headlight (14), a first light distribution command (S3) for instructing the one light distribution pattern (S CALA ), (ii) Obtaining a brightness (S4 A ) of the reference object (30) from first image information (S1 A ) obtained when the area in front of the vehicle is illuminated in accordance with the first light distribution command (S3), (iii) Setting a second light distribution command (S3) for instructing the other light distribution pattern (S CALB ) and providing the same for the headlight (14), (iv) Obtaining a brightness (S4 B ) of the reference object (30) from second image information (S1 B ) obtained when the area in front of the vehicle is illuminated in accordance with the second light distribution command (S3), (v) detecting a difference between the first image information (S1 A ) brightness obtained (S4 A ) of the reference object (30) and the second image information (S1 B ) brightness obtained (S4 B ) of the reference object (30), (vi) when a certain brightness difference is detected in (v), detecting a position deviation amount, and (vii) if the determined brightness difference in (v) is not detected, returning to (iii) and updating the other light distribution pattern (S CALB ) while the part is moved. [4] Vehicle lighting system (2) according to claim 3, wherein: in (iii) for a first time the part is a position of the reference object (30), and when the determined brightness difference in (vi) is detected for the first time, it is determined that the positions of the camera (10) and the headlight (14) are correct. [5] Vehicle lighting system (2) according to claim 3 or 4, wherein: in (iii) the part is gradually removed from a position of the reference object (30) with each update. [6] Vehicle lighting system (2) according to one of claims 1 to 5, wherein: the reference object (30) is a predetermined sign, a beacon and / or a road image drawn on a road surface. [7] Vehicle lighting system (2) according to one of claims 1 to 5, wherein: the reference object (30) is a vehicle (34) driving ahead.

Images