Method for controlling a lighting system of a motor vehicle

Abstract

A method for controlling a lighting system (3) of a main motor vehicle (1) is disclosed, the lighting system comprising a plurality of selectively controllable elementary light sources (32ij), each elementary light source being capable of emitting an elementary light beam (HDij) having a vertical angle of less than 1°, the method comprising the following steps: (E1) detecting a target object (5) by means of a sensor system (2); (E2) determining a vertical angle (α) between a given point (21) of the main vehicle sensor system and a detected point (51) of the target object; (E5) determining from the vertical angle a lower angle (Vinf) and an upper angle (Vsup) between a given point (31) of the lighting system and an upper cut-off point and a lower cut-off point respectively intended to vertically delimit the target object; and (E6) controlling the elementary light sources (32ij) to emit a pixelated road light beam (HD), controlling some of the elementary light sources according to the lower and upper angles to generate a dark zone (Zc) in the light beam extending substantially between the upper cut-off point and the lower cut-off portion.

Description

[0001] The present invention relates to the field of motor vehicle lighting, and more particularly to a method of controlling a lighting system of a motor vehicle to produce a non-glaring pixelated high beam.

[0002] It is known practice to equip motor vehicles with a sensor system for detecting objects on the road that are not to be dazzled and a lighting system for emitting a non-dazzling light beam as a function of the position of the object.

[0003] To this end, these lighting systems are capable of emitting a horizontal segment of a roadway illumination beam and are equipped with a control unit capable of switching on and / or off and / or modifying the light intensity of each elementary beam forming this segment. It is therefore known practice to control this type of lighting system so as to switch off a vertical segment of the entire illumination beam, centered on the horizontal plane of the target object. This lighting system can thus illuminate the road more fully than a conventional low-beam illumination beam without dazzling other road users.

[0004] However, recent lighting system technology has made it possible to emit pixelated horizontal and vertical light beams with exceptionally high vertical resolution. This type of technology has generated significant interest in controlling lighting systems to create pixelated roadway illumination beams that present a dark area horizontally to a target object while also leaving light above and below that dark area. Specifically, unlike beams controlled in a segmented manner, such pixelated illumination beams would allow drivers to perceive gantry traffic signs, objects on the road, or road markings in the near field, or track a moving target object without being distracted by the shifting dark areas within the illumination beam.

[0005] Therefore, there is a need for a method to controllably create such a dark region in such a pixelated light beam, so that the dark region has upper and lower cutoff points that define a target object while leaving light above and below the target object. The present invention is intended to address this need.

[0006] For this purpose, a subject of the invention is a method for controlling a lighting system of a host motor vehicle, the lighting system comprising a plurality of selectively controllable elementary light sources, each elementary light source being capable of emitting an elementary light beam with a vertical aperture angle of less than 1°, the method comprising the following steps:

[0007] a. Detecting the target object through the host vehicle's sensor system;

[0008] b. Determine the vertical angle between a given point of the host vehicle sensor system and the detected point of the target object;

[0009] c. determining the lower and upper angles between a given point of the host vehicle's lighting system and the upper and lower cutoff points intended to define the target object vertically together, respectively;

[0010] d. Controlling elementary light sources of the host vehicle's lighting system to emit a pixelated high beam, controlling some elementary light sources according to the lower and upper angles to produce a dark region in the beam extending substantially between an upper cut-off point and a lower cut-off point.

[0011] It will be appreciated that, with the present invention, certain pixels in a pixelated light beam emitted by a host vehicle's lighting system may be turned off to form a dark region having upper and lower cutoff points that frame or bound a target object, the positions of these cutoff points being defined based on information regarding the vertical positioning of the target object relative to the host vehicle.

[0012] Advantageously, the step of detecting the target object includes detecting a light source of the target object, the detected point being a point of the light source. For example, the sensor system of the host vehicle includes a camera and a computer designed to implement one or more methods for processing images acquired by the camera to detect the light source of the target object. For example, the light source may be a headlight or taillight of the target motor vehicle.

[0013] Preferably, the method includes an intermediate step of comparing the vertical angle with a lower threshold and an upper threshold, the step of determining the lower and upper angles being performed conditional on the vertical angle being between the lower and upper thresholds. For example, the lower threshold may be an angle greater than -1°, in particular equal to -0.7°. For example, the upper threshold may be an angle less than +5°, in particular equal to +4.8°. The reason for this comparison step is that the adaptive road lighting function can only be activated when the host vehicle is traveling at a sufficiently high speed. However, it has been observed that, taking into account the gradient of roads on which motor vehicles may travel at high speeds, the angle between the host vehicle's lighting system and the upper point of the rear window of the preceding target vehicle must not be less than 1° or greater than 5°. Therefore, when the vertical angle is not within the range of the lower and upper thresholds, it is not necessary to generate a dark area in the pixelated light beam, because in this case the host vehicle is not traveling at a speed sufficient to allow the adaptive road lighting function to be activated.

[0014] Advantageously, the step of determining the vertical angle comprises determining the vertical angle between the given point of the host vehicle's sensor system and the detected point of the target object at a given time, the method including the step of predicting the value of the vertical angle at a future time relative to the given time. For example, the given time may correspond to the time at which the sensor system detects the target object, and the lower and upper angles may be determined based on the predicted value of the vertical angle. This feature makes it possible to compensate for delays in the sensors and lighting systems of the motor vehicle. Specifically, between the given time at which the sensor system detects the target object and the time at which the dark region is created in the light beam emitted by the lighting system, the target object may have moved such that the dark region no longer substantially defines the target object, and the light beam may therefore cause glare to the target object. Therefore, predicting the value of the vertical angle at a future time makes it possible to locate the upper and lower cutoff points of the dark region at the position of the target object at that future time.

[0015] Where applicable, the prediction step may include the step of determining a vertical angular velocity of the target object, the prediction of the vertical angle value at a future time being performed using the vertical angular velocity of the target object. For example, the vertical angular velocity may be determined by deriving the value of the vertical angle over time.

[0016] In one embodiment of the present invention, the step of determining the vertical angle includes the step of determining the distance between the host vehicle and the target object, and the value of the lower angle is determined based on the determined distance. For example, the distance between the host vehicle and the target object can be obtained by a method implemented by a computer of the sensor system for processing images captured by a camera of the host vehicle. Advantageously, the value of the lower angle can be obtained by transforming the vertical angle from a reference frame centered on the host vehicle's sensor system to a reference frame centered on the host vehicle's lighting system. For example, the value of the lower angle can be determined using the following equation:

[0017] [Formula 1]

[0018]

[0019] Among them, V inf is the lower angle, α is the value of the vertical angle, D HC is the distance between the host vehicle and the target object, H cam is the height of the host vehicle’s sensor system relative to the road, H HL is the height of the host vehicle's lighting system relative to the road, and D capot is the distance between the sensor system and the lighting system, such as the length of the host vehicle's hood.

[0020] It will be appreciated that the above equations can, in particular, position the lower cutoff point of the dark zone substantially at the detected point of the target object, such as the headlight or taillight of a target vehicle. If desired, the value of the lower angle can be obtained by transforming the vertical angle (subtracting a predetermined margin) by changing the reference frame. In this way, the cutoff point can be positioned below the detected point, for example, at the level of the sill of the target vehicle.

[0021] Advantageously, the step of determining the vertical angle comprises the step of determining the height of the target object, the value of the upper angle being determined by the value of the lower angle and said determined height.

[0022] Advantageously, the step of detecting the target object includes classifying the type of the target object from a set of predetermined target object types, and the height of the target object is determined based on the classified target object type. For example, the type of the object can be determined by a method implemented by a computer of the sensor system for recognizing the shape of the target object based on images captured by a camera of the host vehicle. Where applicable, the set of predetermined target object types can specifically include pedestrians, bicycles, cars, or trucks, each predetermined target object type being associated with a predetermined target object height.

[0023] As a variant, the height of the target object can be obtained by a method implemented by a computer of the sensor system for processing images acquired by a camera of the host vehicle.

[0024] For example, you can use the following equation to determine the value of the upper angle:

[0025] [Formula 2]

[0026]

[0027] Among them, V sup is the upper angle, α is the value of the vertical angle, D HC is the distance between the host vehicle and the target object, H C is the height of the target object, H HL is the height of the host vehicle's lighting system relative to the road, V inf is the value of the lower corner, and D capot is the distance between the sensor system and the lighting system, such as the length of the host vehicle's hood.

[0028] Advantageously, the step of controlling the elementary light sources of the host vehicle's lighting system includes shutting down some elementary light sources that are each capable of emitting an elementary light beam between an upper cutoff point and a lower cutoff point. For example, since each elementary light source is capable of emitting a light beam within a given emission cone defined by its given aperture angle and its emission direction, the step of controlling may include selecting elementary light sources whose emission cones are at least partially located vertically within the interval defined by the lower and upper angles. Where applicable, the step of controlling the elementary light sources may include shutting down some elementary light sources that are each capable of emitting an elementary light beam between the upper and lower cutoff points and between lateral cutoff points delimiting the target object. For example, the two lateral angles between a given point of the lighting system and a left cutoff point and a right cutoff point, respectively, intended to laterally delimit the target object, may be determined from the lateral angle between the given point of the sensor system and the detected point of the target object.

[0029] A further subject matter of the invention is a motor vehicle comprising a sensor system, a lighting system and a control unit which is designed to carry out the method according to the invention.

[0030] Advantageously, the lighting system comprises a plurality of selectively controllable elementary light sources, each elementary light source being capable of emitting an elementary light beam having a vertical opening angle of less than 1°. Where applicable, all elementary light sources can emit pixelated light beams extending vertically within a range of -1° to +5° around the horizontal.

[0031] Advantageously, the elementary light sources are arranged such that the vertical angles of the elementary light beams that they can emit increase towards the top of the pixelated light beam. If desired, the lighting system may comprise:

[0032] a. a plurality of selectively controllable first elementary light sources, each elementary light source capable of emitting an elementary light beam having a vertical angle of substantially 0.25°, wherein all light sources in the plurality of first elementary light sources are capable of emitting a first pixelated sub-beam extending vertically in the range of -1° to +1°;

[0033] b. a plurality of selectively controllable second elementary light sources, each elementary light source being capable of emitting an elementary light beam having a vertical angle of substantially 0.3°, and all of the second elementary light sources being capable of emitting a second pixelated sub-beam extending vertically in the range of +1° to +2°;

[0034] c. a plurality of selectively controllable third elementary light sources, each elementary light source being capable of emitting an elementary light beam having a vertical angle of substantially 0.35°, and all of the light sources in the plurality of third elementary light sources being capable of emitting third pixelated sub-beams extending vertically in the range of +2° to +3°;

[0035] d. A plurality of selectively controllable fourth basic light sources, each basic light source being capable of emitting a basic light beam having a vertical angle of substantially 0.4°, and all of the plurality of fourth basic light sources being capable of emitting a fourth pixelated sub-beam extending vertically in the range of +3° to +5°.

[0036] In one embodiment of the present invention, a lighting system includes a light module, the light module including: a pixelated light source including a plurality of elementary emitters arranged in a matrix array, each elementary emitter forming an elementary light source and capable of being selectively activated to emit a elementary light beam; and a projection optical element associated with the pixelated light source for projecting each of the elementary light beams onto a road. For example, the pixelated light source includes at least one matrix array of light-emitting elements (referred to as a monolithic array), and in particular at least one matrix array of monolithic light-emitting elements, also referred to as a monolithic array.

[0037] As a variant, the light module may comprise a light source formed, for example, by at least one light-emitting diode and a matrix array of optoelectronic elements (for example, a digital micromirror device (DMD)) which direct the light emitted from the at least one light source towards the projection optical element by reflection.

[0038] The invention will now be described by way of examples which are merely illustrative and in no way limitative of the scope of the invention and with reference to the accompanying drawings, in which:

[0039] [ Figure 1 ] schematically and partially illustrates a motor vehicle according to one embodiment of the invention;

[0040] [ Figure 2 ] shows that [ Figure 1 ] a method according to an embodiment of the present invention implemented in a motor vehicle;

[0041] [ Figure 3 ] shows that in [ Figure 1 ]'s vehicle implementation[ Figure 2 ] a side view of a road scene during the method; and

[0042] [ Figure 4 ] shows that in [ Figure 1 ]'s vehicle implementation[ Figure 2 ]’s method during the front view of the road scene.

[0043] In the following description, elements that are identical in structure or function and appear in the various figures have been designated with the same reference numerals unless otherwise specified.

[0044] [ Figure 1] shows a partial view of a main motor vehicle 1 according to one embodiment of the invention. The main motor vehicle 1 comprises a sensor system 2 comprising a camera 21 arranged, for example, at the level of an interior rearview mirror of the vehicle 1 so as to be able to acquire images of the road in front of the vehicle 1, and a computer 22 designed to implement various methods for processing these images. The main vehicle 1 also comprises a lighting system 3 comprising, for example, a light module 31 arranged in a headlight of the vehicle 1. The light module 31 comprises in particular a pixelated light source 32 associated with a lens 33. In the example described, the pixelated light source 32 is a monolithic pixelated light emitting diode, each light emitting element of which forms a basic light source 32 i,j , which can be selectively activated and controlled by the integrated controller to emit light to the lens 33, which thus transmits its light intensity to a basic light beam HD i,j Projected onto the road. Each basic beam HD i,j The lens projects a given emission cone defined by a given emission direction and a given opening angle. Thus, in the example described, all elementary beams HD i,j Thus a pixelated light beam HD is formed with 500 pixels distributed over 25 columns and 20 rows extending vertically within a vertical angle range of -1° to +5°, each pixel being composed of these elementary light beams HD i,j One is formed.

[0045] The basic light source 32 of the light source 32 i,j Each elementary beam emitted by one HD i,j More specifically, the basic light source 32 of the light source 32 has a vertical opening angle of less than 1°. i,j are arranged so that these elementary light sources can emit elementary beams HD i,j The vertical angle of increases towards the top of the pixelated beam. In particular:

[0046] a. Each basic light source having an emission cone in the vertical angle range of -1° to +1° is capable of emitting a basic light beam having a vertical opening angle of substantially 0.25°;

[0047] b. Each elementary light source having an emission cone belonging to the vertical angle range of +1° to +2° is capable of emitting a basic beam having a vertical opening angle of substantially 0.3°;

[0048] c. Each elementary light source having an emission cone belonging to the vertical angle range of +2° to +3° is capable of emitting an elementary light beam having a vertical opening angle of substantially 0.35°;

[0049] d. Each elementary light source having an emission cone falling within the vertical angle range of +3° to +5° is capable of emitting an elementary light beam having a vertical opening angle of substantially 0.4°.

[0050] The light module 31 comprises a controller 34 designed as an integrated controller for controlling the pixelated light source 32 so as to selectively control each elementary light beam HD according to instructions received from the controller 4 of the host vehicle 1 i,j The switching on, switching off and modification of the light intensity of the host vehicle are determined in particular on the basis of information provided by the computer 22 of the sensor system 2 of the host vehicle.

[0051] It should be noted that in the example described, the camera 21 is located at a height H cam and the light module 31 is located at a height H HL These heights are measured relative to the road on which the host vehicle 1 is traveling. In addition, the distance between the camera 21 and the light module 31 is D capot .

[0052] [ Figure 2 ] shows a method implemented by a controller 4 using a sensor system 2 for controlling a lighting system 3 of a host vehicle 1 , the method allowing the lighting system 3 to emit a high beam that does not dazzle a target object 5 . [ Figure 3 ]and[ Figure 4 ] shows a side view and a front view of a road scene onto which the light beam is projected during the implementation of the method. It should be noted that [ Figure 3 ]and[ Figure 4 ] Only a partial view of the beam is shown.

[0053] In a first step E1, the sensor system 2 detects the presence of a target object 5 on the road, in this case a target vehicle 5. In the example described, the computer 22 implements one or more methods for processing the images acquired by the camera 21 to detect light sources in these images, thereby detecting the presence of the taillights 51 of the target vehicle 5.

[0054] In a second step E2 , the computer 22 determines the vertical angle α between the camera 21 of the host vehicle 1 and the taillight 51 of the target vehicle 5 and the distance D between the camera 21 of the host vehicle and the taillight 51 of the target vehicle 5 . HC In addition, the computer 22 classifies the type of the target vehicle in a set of predetermined vehicle types and determines the height H of the target vehicle 5 based on the type of the target vehicle 5 that has been selected. C Each of these operations may be performed by one or more algorithms implemented by the computer 22 for processing the images acquired by the camera 21. All of this information α, D HC and H C All are transmitted to the controller 4 by the computer 22 .

[0055] In step E3, the controller 4 compares the value of the vertical angle α with the lower threshold α min (e.g., -0.7°) and an upper threshold αmax (e.g. +4.8°). If the angle α is not within α min With α max The method stops because it can be inferred that the host vehicle 1 and the target vehicle 5 are traveling on a road where the slope does not allow or does not require a non-glare high beam function. min With α max In the case of , the method proceeds to the next step.

[0056] The vertical angle α determined by computer 22 relates to the position of target vehicle 5 at time t, when camera 21 captured an image that allowed the target vehicle to be identified. However, the various methods implemented by computer 22 of sensor system 2 and the method steps according to the present invention, which will be described below and allow the generation of a non-glaring high beam by lighting system 3, require a given execution time ΔT before the actual emission of the light beam. During this time ΔT, target vehicle 5 may have moved, resulting in the value of vertical angle α no longer corresponding to the actual position of target vehicle 5 at the time the light beam was emitted.

[0057] In order to compensate for this delay, in step E4, the controller 4 predicts the value of the vertical angle α′ between the camera 21 of the host vehicle 1 and the taillight 51 of the target vehicle at a future time t+Δt relative to the time t at which the camera 21 acquires the image allowing the determination of the vertical angle α in step E2. For this purpose, the controller 4 determines the vertical angular velocity of the target vehicle by deriving a value from the various values ​​of the vertical angle α previously determined in step E2. Therefore, the predicted value α' can be obtained using the following equation:

[0058] [Formula 3]

[0059]

[0060] where α is the value of the vertical angle at time t determined in step E2, α' is the predicted value of the vertical angle at the future time t+Δt, is the vertical angular velocity of the target vehicle 5 and Δt is the delay of the method according to the invention.

[0061] In step E5 , the controller 4 determines the lower angle V between the light module 31 and the taillight 51 of the target vehicle 5 . inf Therefore, the controller 4 transforms the predicted vertical angle α′ using the following equation by changing the reference frame from the reference frame centered on the camera 21 of the sensor system 2 to the reference frame centered on the light module 31 of the host vehicle's lighting system 3 :

[0062] [Formula 4]

[0063]

[0064] Among them, V inf is the lower angle, α' is the value of the vertical angle predicted in step E4, D HC is the distance between the host vehicle 1 and the target vehicle 5 determined in step E2, H cam is the height of the sensor system 2 of the host vehicle 1 relative to the road, H HL is the height of the lighting system 3 of the host vehicle 1 relative to the road, and D capot is the distance between the sensor system 2 and the lighting system 3.

[0065] H cam 、H HL and D capot The value of is known in advance and stored in the memory of the controller 4 .

[0066] Furthermore, still in step E5, the controller 4 obtains the lower angle V from the previously obtained inf The value of and the height H of the target vehicle determined in step E2 C For example, use the following equation to determine the upper angle V sup :

[0067] [Formula 5]

[0068]

[0069] Among them, V sup is the upper angle, α is the value of the vertical angle predicted in step E4, D HC is the distance between the host vehicle 1 and the target vehicle 5 determined in step E2, H C The height of the target vehicle determined in step E2, H HL is the height of the host vehicle's lighting system relative to the road, V inf is the value of the lower corner, and D capot is the distance between the sensor system 2 and the lighting system 3.

[0070] After step E5 is completed, the controller 4 sets the pair of lower corners V inf and upper corner V sup is transmitted to the controller 34 of the light module 31. In addition, in a step not described, the controller 4 determines a pair of right lateral angles V from the positions of the taillights 51 of the target vehicle 5, respectively. LD and left lateral angle V LG , and also transmits this diagonal angle to the controller 34.

[0071] In step E6, the controller 34 selects a light source 32 capable of emitting light whose emission cone is vertically at least partially located at the lower angle V inf With upper angle V sup between and horizontally at least partially located at the right lateral angle VLD With left horizontal angle V LG Basic Beam HD i,j Those basic light sources 32 i,j The controller 34 thus controls these selected elementary light sources 32 i,j Thus, the light module 1 emits a pixelated high beam HD in which a dark zone Zc is formed, the dark zone being centered on the target vehicle 5 and being vertically delimited by a lower cut-off point and an upper cut-off point each forming a vertical angle with the light module 1, the values ​​of these vertical angles being substantially V inf and V sup and is defined by the right and left cutoff points forming a horizontal angle with the optical module 1, and the values ​​of these horizontal angles are substantially V LD and V LG It should be noted that the term "substantially" should here be interpreted in relation to the vertical and horizontal resolution of the pixelated light beam HD.

[0072] The foregoing description clearly explains how the invention achieves the set objectives, in particular by providing a method for controlling a lighting system of a host vehicle, which controls the switching on or off of an elementary light source of the lighting system so as to create a dark zone in a pixelated light beam, delimited by an upper cut-off point and a lower cut-off point, the position of which dark zone is determined on the basis of information from a sensor system of the host vehicle and, in particular, relates to the vertical position of a target object on the road which should not be dazzled.

[0073] In any case, the invention should not be considered limited to the embodiments specifically described in this document, but in particular extends to any equivalent means and any technically operative combination of these means. In particular, in addition to the light modules described, other types of light modules can be envisaged, in particular light modules comprising a combination of a light source and a matrix array of selectively activatable micromirrors. Other methods can also be envisaged for determining the various values ​​used in the equations allowing the determination of the values ​​of the lower and upper angles, or even the various values ​​used in equations other than those already described, and in particular the various values ​​used in the equations containing the margin for vertical movement of the position of the upper and lower cut-off points of the dark areas in the pixelated light beam.

Claims

1. A method for controlling a lighting system (3) of a host vehicle (1), said lighting system comprising a plurality of selectively controllable elementary light sources (32 i,j ), each basic light source can emit a basic light beam with a vertical angle of less than 1° (HD i,j ), the method comprising the following steps: (E1) detecting a target object (5) by a sensor system (2) of the host vehicle; (E2) determining a vertical angle (α) between a given point (21) of the host vehicle sensor system and a detected point (51) of the target object; (E5) determining from the vertical angle the lower angle (V) between the given point (31) of the lighting system of the host vehicle and the upper and lower cut-off points that together vertically define the target object. inf ) and upper angle (V sup ); (E6) controlling a primary light source of a lighting system of the host vehicle to emit a pixelated high beam (HD), A number of elementary light sources are controlled according to the lower and upper angles to generate a dark zone (Z) in the light beam extending substantially between the upper cut-off point and the lower cut-off point. C ); The step (E2) of determining the vertical angle (α) is a step of determining the vertical angle between the given point (21) of the sensor system (2) of the host vehicle (1) and the detected point (51) of the target object (5) at a given time (t), the method comprising a step (E4) of predicting the value (α') of the vertical angle at a future time (t+Δt) relative to the given time; The prediction step (E4) comprises determining the vertical angular velocity of the target object (5) In the step of predicting (E4) the value (α') of the vertical angle at a future time (t+Δt) is performed using the vertical angular velocity of the target object.

2. The method according to claim 1, wherein The step (E1) of detecting the target object includes detecting a light source (51) of the target object (5), the detected point being a point of the light source.

3. The method according to claim 1 , comprising comparing the vertical angle (α) with a lower threshold (α min ) and upper threshold (α max ) is compared with the intermediate step (E3), determining the lower angle (V inf ) and upper angle (V sup ) is performed on the condition that the vertical angle is between the lower threshold and the upper threshold.

4. The method according to claim 1, wherein: The step of determining the vertical angle (α) comprises determining the distance (D HC ) step (E2), the lower corner (V inf ) is determined by the determined distance.

5. The method according to claim 4, wherein: The step of determining the vertical angle (α) comprises determining the height (H) of the target object (5) C ) step (E2), the upper corner (V sup ) is obtained by the lower angle (V inf ) value and the determined height.

6. The method according to claim 5, wherein: The step (E1) of detecting the target object (5) comprises classifying the type of the target object from a set of predetermined target object types, and wherein the height (H C ) is determined based on the target object type of the classification.

7. The method according to any one of the preceding claims, wherein Controlling a primary light source (32) of a lighting system (3) of the host vehicle (1) i,j The step (E6) comprises shutting down each of the plurality of primary light beams (HD) that can be emitted between the upper cut-off point and the lower cut-off point. i,j ) some basic light sources.

8. A vehicle (1) comprising a sensor system (2), a lighting system (3) and a controller (4), the controller being designed to implement the method as claimed in one of the preceding claims.

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