Method for controlling a lighting system using a glare-free illumination function

Abstract

The invention relates to a method for controlling a lighting system (3) of a motor vehicle (1), said lighting system comprising a plurality of elementary light sources (32i,j), each elementary light source being selectively controllable in order to emit an elementary light beam (HDi,j), said method comprising the following steps: (E1) detecting a road sign (10) by means of a sensor system (2) of said motor vehicle; (E2) estimating a passing time (TBC) between the moment of detection (t0) and a future moment (t1) at which said motor vehicle will pass the detected road sign; (E61, E63) controlling said elementary light sources of the lighting system of the host vehicle in order to emit a pixelated light beam, some of said elementary light sources being controlled according to a growth time in order to create a lower intensity zone (ZC) extending to said road sign.

Description

Technical Field

[0001] This invention relates to the field of motor vehicle lighting. More specifically, this invention relates to a method for controlling a motor vehicle lighting system using an anti-glare lighting function. Background Technology

[0002] Motor vehicles are typically equipped with lighting systems that, among other things, allow the emission of adjustable high beam type lighting functions that can optimally illuminate the road downstream of the vehicle.

[0003] While this type of beam allows for a satisfactory increase in driver visibility, it can also be a source of driver discomfort. In fact, the beam of a high beam can reach road signs and reflect back towards the driver. This reflection can be a source of glare, especially if the sign has a reflector, if the beam's power is particularly high, if the ambient light is already bright, or even if the driver is sensitive to glare.

[0004] It is known that motor vehicles are equipped with a sensor system and a controller. The sensor system detects road signs on the road, and the controller can switch the lighting system to emit a glare-free beam, such as a low beam, when the sign is detected. In this way, glare sources can be eliminated to reduce driver discomfort.

[0005] However, this solution is unsatisfactory. Firstly, emitting such a glare-free beam also reduces illumination of the rest of the road, suboptimal driver visibility. Secondly, road signs are no longer illuminated, and drivers can no longer perceive and understand them. Finally, modern vehicles are typically equipped with cameras that enable driver assistance functions, which may require the camera to read the sign. In this case, the lack of illumination on the sign prevents the camera from reading it, causing the driver assistance function to fail.

[0006] A solution is needed that overcomes the various drawbacks listed and, in particular, allows the emission of light beams that can optimally illuminate the road, including road signs, without creating glare for drivers near those signs. Summary of the Invention

[0007] This invention falls within this context and aims to address this need.

[0008] Therefore, the object of the present invention is a method for controlling a lighting system of a motor vehicle, the lighting system comprising a plurality of basic light sources, each of which is selectively controllable to emit a basic beam of light, the basic beams together forming a pixelated beam of light, the method comprising the following steps:

[0009] a. Detecting road signs using the sensor system of the motor vehicle;

[0010] b. Estimate the elapsed duration between the moment the road sign is detected and the future moment when the motor vehicle will pass the detected road sign;

[0011] c. Controlling the base light source of the lighting system of the main vehicle to emit a pixelated beam, wherein a portion of the base light source is controlled based on the elapsed duration to produce a lower intensity area extending in the beam near the road sign.

[0012] By means of the present invention, and particularly by means of the use of an illumination system capable of emitting pixel beams, the entire road downstream of a motor vehicle, including the road near a road sign, can be illuminated while emitting less light near the sign to avoid glare-inducing reflections on the sign. Furthermore, it has been found that estimating the duration of the separation between the moment a road sign is detected and the future moment when a motor vehicle will pass the detected road sign allows for precise and intelligent control of the amount of light that must be emitted toward the sign, thereby optimizing the detection and understanding of the sign by the driver or camera of the motor vehicle.

[0013] The lower intensity region is understood to be the area illuminated by all the fundamental beams emitted by the fundamental light source of the portion, wherein each fundamental beam emitted by the fundamental light source in this region has a light intensity lower than the nominal light intensity that the fundamental light source may emit. For example, the light intensity of this fundamental beam may be significantly lower than the light intensity of each of the fundamental beams that form the rest of the pixelated beam.

[0014] Advantageously, the process of detecting road signs can be performed by cameras mounted on motor vehicles.

[0015] In one embodiment of the invention, during the detection step, the sensor system estimates the distance between the motor vehicle and the road sign, and during the step of estimating the elapsed duration, estimates the elapsed duration based on the distance and the speed of the main motor vehicle. If necessary, the sensor system estimates the distance between the sensor system and the road sign and the angle between the sensor system and the road sign, and during the step of estimating the elapsed duration, estimates the elapsed duration based on the distance, the angle, and the speed of the motor vehicle.

[0016] In another embodiment of the invention, during the detection step, the sensor system determines the illuminance of the road sign by the lighting system. If applicable, during the step of estimating the elapsed duration, the distance between the motor vehicle and the road sign is estimated based on the determined illuminance and the light intensity emitted by the lighting system toward the sign, and during the step of estimating the elapsed duration, the elapsed duration is estimated based on the distance and the speed of the motor vehicle. Therefore, the method according to the invention can be deployed on vehicles equipped with low-performance sensor systems. For example, in the case where the sensor system includes a camera capable of acquiring road images, the illuminance of the road sign can be determined using the intensity of each pixel in the image located near the road sign or based on the brightness of the road sign that the camera can estimate. When the light intensity emitted by the directional lighting system is known in advance, since it is the setpoint of the base light source, the distance between the motor vehicle and the road sign can be calculated, for example, by means of Bouguer's law, which is formulated by the following equation.

[0017] [Mathematical Expression 1]

[0018]

[0019] Where E is the illuminance of the road sign by the lighting system; I is the light intensity emitted by the lighting system toward the road sign; d is the distance between the motor vehicle and the road sign; and θ is the angle between the normal to the surface of the road sign and the emission direction of the lighting system, which can be considered as zero.

[0020] Advantageously, the method may include the steps of estimating the glare level of the road sign to the driver of the motor vehicle and comparing the glare level with a given glare threshold, wherein the step of controlling the base light source to produce the lower intensity region in the light beam is conditioned on the fact that the glare level is greater than the given glare threshold. Based on this feature, the anti-glare function of the road sign may not be activated when the road sign is not considered glaring. In this case, the road sign is therefore illuminated by a pixelated light beam with nominal intensity.

[0021] For example, the brightness of a road sign can be determined, and then the glare level can be estimated based on the logarithm of that brightness. Specifically, the glare level is defined using the following values ​​based on the De Boer scale, which describes the intensity of perceived discomfort: 1 (very insignificant); 3 (acceptable); 5 (disturbing); 7 (comfortable); 9 (unbearable). For example, the glare threshold can be set to 3.

[0022] In alternative or superimposed examples, the sensor system can estimate the brightness and size of a road sign, wherein the step of controlling a base light source to produce the lower intensity region in the light beam is conditional on the fact that the brightness of the road sign is greater than a given threshold and on the fact that the size of the road sign is greater than a given threshold.

[0023] Advantageously, the method includes a step of comparing the elapsed duration (particularly the elapsed duration estimated when the step of detecting the road sign is completed) with a minimum threshold. If the elapsed duration is less than the minimum threshold, then during the step of controlling the base light source, each base light source for the portion used to generate the lower intensity region is controlled to emit a base beam of constant intensity as the vehicle moves toward the road sign. According to this feature, when the vehicle gets too close to the road sign, the light intensity emitted toward the road sign decreases to a constant value that is unlikely to produce dazzling reflections, but is just sufficient to allow the driver or camera of the vehicle to perceive and understand the road sign. For example, the constant intensity can vary in the range of 20% to 30% of the nominal light intensity that might be emitted by the base light source, and in particular, can be equal to 26%.

[0024] Advantageously, the method includes a step of comparing the elapsed duration (particularly the elapsed duration estimated when the step of detecting the road sign is completed) with a minimum threshold. If the elapsed duration is greater than the minimum threshold, during the step of controlling the base light sources, each base light source used to generate the portion of the lower intensity region is controlled to emit a base beam whose intensity decreases as the vehicle moves toward the road sign. This feature ensures that the brightness of the road sign caused by the lighting system illuminating the road sign decreases as the time interval between the future moment when the vehicle will pass the road sign and the current moment decreases. This ensures that the illuminance of the road sign is insufficient to dazzle the driver due to reflection, but sufficient for the driver or camera to perceive and understand the road sign while the vehicle is moving. Still advantageously, when the elapsed duration decreases below a given minimum threshold, during the step of controlling the base light sources, each base light source used to generate the portion of the lower intensity region is controlled to emit a base beam with a constant intensity as the vehicle moves toward the road sign.

[0025] Preferably, the method includes the step of selecting a control law from a plurality of control laws based on the value of the elapsed duration, wherein each control law defines the evolution of the light intensity to be emitted according to an increasing function of time. If applicable, each base light source used to generate the portion of the road sign is controlled to emit a base beam, the intensity of which is determined by the selected control law based on the value of the remaining time before the vehicle passes the road sign. In other words, from the moment the road sign is detected, while the vehicle is moving, the remaining time before the vehicle passes the road sign is periodically estimated, and the intensity of the light source is redefined for each value of that remaining time. Thus, multiple illumination curves for the road sign are defined by the lighting system to optimize the driver's or camera's perception and understanding of the road sign as the vehicle moves.

[0026] If necessary, each of the plurality of control laws is associated with at least one different elapsed duration, and in particular with a range of different elapsed durations. If applicable, the increment function of each control law has a growth rate, and for a first control law associated with an elapsed duration greater than that associated with the second control law, the growth rate of the increment function of the first control law is less than the growth rate of the increment function of the second control law.

[0027] For example, the increasing function of each control law can be a power function of time, and the exponent of this power function is related to the elapsed duration associated with that control law. For example, this power function can be defined by the following equation:

[0028] [Mathematics 2]

[0029]

[0030] Where I is the light intensity emitted by each base light source of the portion of the lighting system; ttc is a variable representing the remaining time before the vehicle passes the road sign, and the value of this variable is between 0 and the elapsed duration; α i It is the magnitude of the power function associated with control rule i; and β i It is the exponent of the power function associated with the control rule i.

[0031] Therefore, it can be understood that the longer the estimated elapsed time when a road sign is detected, the greater the exponent β of the power function of the control law to be selected. i The lower the magnitude α of the power function of the control law to be selected, and / or the better. iThe larger the value, the more efficient the reduction in brightness of the road sign. In this way, based on this initial elapsed duration, the brightness of the road sign decreases relatively quickly toward a constant value. Advantageously, for each of the plurality of control laws, the exponent β of the power function associated with that control law... i Less than 2.

[0032] Advantageously, during the step of controlling the base light source, the base light source can be controlled to emit a pixelated beam of the type that is glare-free and has a long beam.

[0033] Preferably, during the step of controlling the base light source, the portion of the base light source can be controlled based on the elapsed duration to generate an area in the beam having an edge surrounding the road sign.

[0034] For example, the sensor system can be arranged to estimate a pair of horizontal angles between the sensor system and the lateral end of the road sign and / or a pair of vertical angles between the sensor system and the upper and lower ends of the road sign during the step of detecting a road sign. If applicable, the method may include steps such as determining a pair of horizontal and / or vertical angles between the lighting system and the lateral end and / or the upper and lower ends by means of a reference substitution operation. The base light source for the portion that must be controlled to produce the lower intensity area is a base light source capable of emitting a base beam whose emission cone is at least partially included in the horizontal and / or vertical directions within the range defined by the previously determined pair of horizontal and / or vertical angles. Advantageously, as the vehicle moves, the determined pairs of angles and these steps of controlling the base light source are periodically updated so that the edge of the area surrounds the road sign during this movement.

[0035] Advantageously, the portion of the base light source is controlled to produce a lower intensity region in the beam throughout the entire duration of the vehicle's travel, spanning from the moment the road sign is detected to a future moment when the vehicle will pass the detected road sign. If applicable, the portion of the base light source can be controlled after the vehicle has passed the road sign so that each base light source produces a base beam of nominal intensity.

[0036] Another object of the present invention is a motor vehicle comprising a sensor system, a lighting system and a controller, wherein the controller, sensor system and lighting system are arranged to implement the method according to the present invention.

[0037] Advantageously, the lighting system includes a plurality of selectively controllable base light sources, each of which is capable of emitting a base beam, particularly having a vertical angular aperture of less than 1°. If applicable, all base light sources are capable of emitting pixelated beams extending horizontally in the range of -16° to +16° and vertically in the range of -1° to +6° around the horizon.

[0038] In one embodiment of the invention, the lighting system includes a light module comprising a pixelated light source comprising a plurality of base emitters arranged in a matrix, each of the base emitters forming a base light source and being selectively activated to emit a base beam, and an optical projection element associated with the pixelated light source to project each of the base beams onto a road. For example, the pixelated light source comprises at least one matrix of light-emitting elements (referred to as a monolithic array), and particularly at least one matrix of light-emitting elements, also referred to as a monolithic array.

[0039] As an alternative embodiment, the optical module may include, for example, a light source formed by a matrix of at least one light-emitting diode and photoelectric elements, and a matrix of micromirrors (also known as a DMD (Digital Micromirror Device)) that directs light originating from the at least one light source to an optical projection element by reflection. Attached Figure Description

[0040] The invention will now be described using examples that are merely illustrative and not intended to limit the scope of the invention, as well as the accompanying drawings, in which the various figures are shown:

[0041] [ Figure 1 A motor vehicle according to an embodiment of the present invention is illustrated schematically and in part.

[0042] [ Figure 2 The image shows an embodiment of the invention, consisting of […]. Figure 1 The method of implementation of motor vehicles;

[0043] [ Figure 3 ] shows when [ Figure 1 The vehicles implemented [ Figure 2 The side view of the road scene when using the method described above;

[0044] [ Figure 4 ] shows when [ Figure 1 The vehicles implemented [ Figure 2 The front view of the road scene when using the [method];

[0045] [ Figure 5 ] shows in [ Figure 2Examples of control laws used in the method; and

[0046] [ Figure 5 ] showed [ Figure 2 Examples of implementations of the method. Detailed Implementation

[0047] Throughout the following description, unless otherwise stated, elements that are structurally or functionally consistent and appear in the figures are denoted by the same reference numerals.

[0048] [ Figure 1 The image shows a partial view of a motor vehicle 1 according to an embodiment of the present invention. The motor vehicle 1 includes a sensor system 2 having a camera 21 arranged to acquire images of a road downstream of the motor vehicle. The sensor system 2 also includes a computer 22 arranged to implement various methods for processing the images acquired by the camera 21.

[0049] The motor vehicle 1 also includes a lighting system 3, which includes a light module 31. The light module 31 specifically includes a pixelated light source 32 associated with a lens 33. In the described example, the pixelated light source 32 is a monolithic pixelated light-emitting diode, for which each of the light-emitting elements forms a basic light source 32. i，j The basic light source 32 i，j The base light source 32 can be activated and selectively controlled by an integrated controller to emit light toward lens 33, thereby enabling the base light source 32 to... i，j HD of the basic beam i，j Projected onto the road, the basic beam HD i，j The light intensity is controllable. Each fundamental beam HD i，j The beam is projected by a lens into a given emission cone, defined by a given emission direction and a given angular aperture. Therefore, in the described example, all fundamental beams HD... i，j This forms a pixelated beam HD with 500 pixels distributed across 25 columns and 20 rows, extending horizontally in a horizontal angle range of -16° to +16° and vertically in a vertical angle range of -1° to +6°, and each pixel of the pixelated beam HD is composed of these base beams HD. i，j One of the formations. The basic light source 32 is formed by light source 32. i，j Each fundamental beam of HD emitted by a fundamental light source i，j It has horizontal and vertical apertures of less than 1°.

[0050] The optical module 31 includes a controller 34, which is arranged as an integrated controller to control the pixelated light source 32 in order to selectively control the base beam HD based on instructions received from the computer 4 of the host vehicle 1. i，j The on / off state and light intensity modification of each of them are determined specifically based on information provided by computer 22 of sensor system 2.

[0051] [ Figure 2 [This illustrates a method for controlling a lighting system 3 according to an embodiment of the present invention. Referring to [...]] Figure 3 ]and[ Figure 4 To describe this method, [ Figure 3 ]and[ Figure 4 ] respectively describe the implementation [ Figure 2 When using the method, the side view and front view of the road scene are displayed.

[0052] In step E1, sensor system 2 detects road signs 10 on the road. Road signs 10 have a generally circular, triangular, or rectangular shape, typically have a reflective coating, and include text and / or pictographs. Therefore, the presence of such signs can be detected in the image acquired by camera 21, particularly due to the fact that ambient light and light emitted by various different road users are reflected towards camera 21. Therefore, computer 22 is provided with means for processing the image, thereby enabling this detection.

[0053] Following the detection, computer 22 determines various features of road sign 10 in step E11, and specifically:

[0054] a. Horizontal angles θ1 and θ2 between the camera 21 and the lateral end of the road sign 10;

[0055] b. The vertical angles ω1 and ω2 between the upper and lower ends of the camera 21 and the road sign 10;

[0056] c. The distance d between camera 21 and road sign 10.

[0057] In step E12, computer 22 determines the brightness L of road sign 10 produced by the reflection of light emitted by lighting system 3.

[0058] Finally, this luminance L allows the computer to estimate the glare level Y in the same step based on the logarithm of the luminance L, which is brought back to the range of 1 to 10 corresponding to the De Boer scale.

[0059] Computer 4 has a set of parameters. In step E2, the computer estimates the duration TBC of the separation between time t0 and the future time t1 when the vehicle 1 will pass the road sign 10, based on the distance d determined by the sensor system 2 at time t0 when the road sign 10 is detected. Specifically, the duration TBC can be calculated using the distance d and the speed v of the vehicle 1 at time t0, where the computer 4 knows the speed v.

[0060] In step E3, the glare level Y is compared with a given glare threshold TS on the De Boer scale. Y (For example, a value of 3) are compared.

[0061] The glare level Y is actually greater than the glare threshold TS. Y In the case of step E4, computer 4 determines the horizontal angle V between the lighting system 3 and the upper, lower, and lateral ends using a reference substitution operation based on horizontal angles θ1 and θ2 and vertical angles ω1 and ω2. LG and V LD and vertical angle V upp and V low Therefore, computer 4 selects the one capable of emitting the fundamental beam HD. i，j Basic light source 32 i，j The basic beam HD i，j The launching cone is at least partially included in the horizontal and / or vertical directions at the angle V of the previously determined pair. LG and V LD and V upp and V low Within a limited scope.

[0062] In step E5, the duration TBC is compared with the minimum threshold TS. min Compare them.

[0063] If the duration TBC is less than the minimum threshold TS min In step E61, computer 4 sends a control setpoint to controller 34, so that the selected base light source 32... i，j Each of the TBCs emits a fundamental beam of constant intensity I HD throughout the entire duration. i，j This constant intensity I is lower than the aforementioned nominal light intensity that the light source can emit. For example, this constant intensity is equal to 26% of the nominal light intensity.

[0064] Therefore, it can be understood that, relative to the rest of the pixelated beam HD, the selected light source 32 i、j Together, they generate a lower intensity region Z. C The lower intensity region Z CThe edge surrounds road sign 10. Throughout the entire movement of vehicle 1 between time t0 and time t1 (during which the detection and estimation of horizontal and vertical angles θ1, θ2, ω1, and ω2 are periodically updated), this region Z... C The status remains active and centered on road sign 10.

[0065] If the duration TBC is less than the minimum threshold TS min In step E62, computer 4 compares the elapsed duration TBC with multiple elapsed duration ranges. In the described example, the elapsed duration TBC is compared with a first threshold TS1 and a second threshold TS2 greater than TS1, thereby defining three ranges, namely TS... min - TS1, TS1-TS2 and durations greater than TS2.

[0066] Each range is associated with control laws L1, L2, and L3, for which the control laws define the evolution of light intensity I based on an increasing function of the remaining time before vehicle 1 passes road sign 10.

[0067] In the described example, each function is a power function of the remaining time ttc, with the exponent of the power function predetermined based on the associated range. Therefore, the remaining time ttc is a time variable that decreases from the elapsed duration TBC until it reaches 0.

[0068] More specifically, with range TS i -TS j Related Laws L i The exponent β i Greater than or equal to a larger range of TS j -TS k Related Laws L j The exponent β j In other words, with range TS min The exponent β1 of the law L1 associated with TS1 is greater than the exponent β2 of the law L2 associated with the range TS1-TS2, and the exponent β2 of the law L2 is itself greater than the exponent β3 of the law L3 associated with the range whose duration is greater than TS2.

[0069] [ Figure 5 The various functions of rules L1 to L3 are shown on the same graph. It can be seen that the growth rate of L1 is therefore greater than the growth rate of L2, and the growth rate of L2 itself is greater than the growth rate of L3.

[0070] In step E62, computer 4 therefore selects rule L which is associated with the range of the estimated value TBC when road sign 10 is detected. iThen, in step E63, computer 4 periodically estimates the remaining time ttc and sends the control setpoint to controller 34, so that the selected base light source 32... i、j Each of the emitted fundamental beams HD i、j By means of the chosen law L i The fundamental beam HD is determined based on the estimated remaining time ttc. i、j The intensity I. It should be noted that if the estimated remaining time ttc at a given time drops below the threshold TS... min The setpoint issued by computer 4 is a constant value of 26% for the remainder of its entire movement, as per step E61.

[0071] [ Figure 6 The same graph illustrates three scenarios for implementing the method according to the invention, for three different values ​​of the estimated elapsed duration TBC when a road sign is detected at time t0, where each of these values ​​lies within a different range. Each curve I1, I2, and I3 represents the time when motor vehicle 1 is moving in region Z. C The selected base light source 32 i、j The emitted light intensity is expressed as a percentage (%) of nominal intensity, where the horizontal axis represents time. More specifically, curve I1 is obtained by rule L1, curve I2 by rule L2, and curve I3 by rule L3.

[0072] Therefore, it can be seen that these intensities begin to decrease from the moment t0 when road sign 10 is detected, until the remaining time ttc drops below the threshold TS. min Up to time t0', the light intensity is assumed to be a constant value of 26%. Once time t1 is reached, where the value ttc has therefore reached 0 and is passing light flag 10, the light intensity can return to 100% of the nominal value.

[0073] It can also be seen that, due to the use of rules L1, L2, and L3, the earlier road sign 10 is detected, the better it is in region Z. C The less the light intensity emitted, the better. Therefore, optimal illumination of the road sign 10 can be ensured when the motor vehicle 1 is moving, allowing the driver or camera 21 to continuously perceive and understand the road sign throughout the movement, without producing dazzling reflections.

[0074] It should be noted that the basic light source is 32. i，j The remaining portion can implement glare-free road lighting functions, specifically by attenuating or disabling the base light source that could glare the drivers of oncoming or following target vehicles.32 i，j To achieve this.

[0075] The above description clearly explains how the invention allows the achievement of its intended objectives, and in particular by proposing a method for controlling a vehicle's lighting system that allows for optimized detection and understanding of road signs by the vehicle's driver or camera while the vehicle is in motion, without any risk of the sign producing glare.

[0076] In no event should this invention be considered limited to the embodiments specifically described herein, but should be extended in particular to any equivalent means and any technical combination of operations of such means. In particular, types of optical modules other than those described are conceivable, and specifically, optical modules comprising a combination of a light source and a matrix of selectively activatable micromirrors. It is also conceivable to estimate the distance between a motor vehicle and a road sign, for example, based on the illuminance of the road sign measured by a sensor system, and using Bouguer's law. Multiple control laws, different from those already described and / or with curves different from the functions of these control laws already described, are also conceivable.

Claims

1. A method for controlling a lighting system (3) of a motor vehicle (1), said lighting system comprising a plurality of base light sources (32) i，j ), each basic light source (32 i，j It is selectively controllable in order to emit the fundamental beam (HD). i，j The base beams together form a pixelated beam (HD), and the method includes the following steps: a. (E1) Detect road signs (10) through the sensor system (2) of the motor vehicle; b. (E2) Estimate the elapsed duration (TBC) between the time when the road sign is detected (t0) and the future time (t1) when the motor vehicle will pass the detected road sign. c. (E61, E63) Controlling the base light source of the lighting system of the main vehicle to emit a pixelated beam, wherein a portion of the base light source is controlled based on the elapsed duration to produce a lower intensity region (Z) extending in the beam near the road sign. C ), The method further includes combining the elapsed duration (TBC) with a minimum threshold (TS). min In the step of comparison (E5), if the elapsed duration is greater than the minimum threshold, then the base light source (32) is controlled. i，j During step (E63), control is applied to generate the lower intensity region (Z). C Each of the aforementioned basic light sources is configured to emit a basic beam (HD) i，j ), the basic beam (HD) i，j The intensity (I) of the sign (10) decreases as the motor vehicle (1) moves toward the road sign (10). The method further includes selecting a control law (L1, L2, L3) from multiple control laws (L4, L5, L6) based on the value of the elapsed duration (TBC). i Step (E62) involves each control law defining the evolution of the emitted light intensity (I) according to an increasing function of time, and wherein control is used to generate the lower intensity region (Z). C Each of the basic light sources (32) of the aforementioned portion i，j In order to emit a fundamental beam (HD) i，j Using the selected control law, the base beam (HD) is determined based on the value of the remaining time (ttc) before the motor vehicle passes the road sign. i，j The strength of ) Among them, each of the multiple control laws (L1, L2, L3) is a control law (L... i ) and at least one different elapsed duration (TS) min The incremental function of each control rule (TS1, TS2) is associated with a growth rate, and wherein, for a first control rule associated with an elapsed duration greater than that associated with the second control rule, the growth rate of the incremental function of the first control rule is less than the growth rate of the incremental function of the second control rule.

2. The method according to the preceding claim, wherein, During detection steps (E1) and (E11), the sensor system (2) estimates the distance (d) between the motor vehicle (1) and the road sign (10), and wherein, during the step of estimating the elapsed duration (E2), the elapsed duration (TBC) is estimated based on the distance and the speed (v) of the motor vehicle.

3. The method according to claim 1, wherein, During detection steps (E1) and (E11), the sensor system determines the illuminance (E) of the road sign (10) by the lighting system (2), wherein, during step (E2) of estimating the transit time (TBC), the distance (d) between the motor vehicle (1) and the road sign is estimated based on the determined illuminance and the light intensity (I) emitted by the lighting system toward the sign, and wherein, during step of estimating the transit time, the transit time is estimated based on the distance and the speed (v) of the motor vehicle.

4. The method according to any one of the preceding claims, characterized in that, The method includes estimating the glare level (Y) of the driver of the motor vehicle (1) by the road sign and comparing the glare level with a given glare threshold (TS). Y The comparison step (E12) involves controlling the base light source (32) i，j In order to produce the lower intensity region (Z) in the beam (HD). C Steps (E61, E63) are conditional on the fact that the glare level is greater than the given glare threshold.

5. The method according to any one of claims 1-3, characterized in that, The method includes setting the elapsed duration (TBC) and a minimum threshold (TS). min In the step of comparison (E5), if the elapsed duration is less than the minimum threshold, then in controlling the base light source (32) i，j During step (E61), control is applied to generate the lower intensity region (Z). C Each of the aforementioned basic light sources emits a basic beam (HD) of constant intensity (I) as the motor vehicle (1) moves toward the road sign (10). i，j ).

6. The method according to claim 1, wherein, The increment function of each control rule (L1, L2, L3) is a power function of time (ttc), and the exponent (β1, β2, β3) of the power function is related to the elapsed duration (TS) of that control rule. min (TS1, TS2) are related.

7. A motor vehicle (1) comprising a sensor system (2), a lighting system (3), and a controller (4), said controller being arranged to implement the method according to any one of the preceding claims.

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