METHOD FOR CONTROLLING DIRECTED LIGHTING AND LIGHTING DEVICE FOR IMPLEMENTING THIS METHOD

Description

[0001] The present invention relates to a method for controlling directional lighting emitted by a vehicle lighting device towards a road scene, wherein the image of the light beam is adapted to each direction of vehicle movement. The invention also relates to a vehicle lighting device implemented by this method.

[0002] The invention has applications in the field of road lighting by road vehicles, such as motor vehicles. In particular, it has applications in the field of directional lighting where the lighting varies according to the vehicle's movement. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] For safety reasons, automotive lighting systems have evolved considerably in recent years to improve driver visibility while complying with current regulations. To enhance driver visibility, some lighting systems, or headlights, adapt the light beam based on vehicle speed, weather conditions, oncoming traffic, and other factors. Certain improvements are available for fixed bending light (FBL) systems. Other improvements are available for dynamic bending light (DBL) systems.

[0004] In dual-beam headlights (DBL) systems, the lighting devices follow the vehicle's trajectory, for example, when cornering, to best illuminate the road ahead for the driver. Generally, the beam pattern of the headlights is shifted to the right or left depending on the steering wheel angle and / or vehicle speed to more intensely illuminate the road in the direction the vehicle is traveling. In DBL systems, the light beams are typically formed by light-emitting diodes (also called LEDs), arranged in a line or in a grid (i.e., in multiple rows and columns), and whose intensity can be varied. Thus, with LED lighting, the luminous flux emitted by the headlight can vary, creating a beam pattern with varying intensity across different areas of the image.An example of such a luminous flux image, also called photometry, is shown on the [. Fig.1 This image of the [ Fig.1 ] corresponds to an image of luminous flux emitted by a projector when the vehicle is traveling in a straight line.

[0005] One of the current DBL techniques involves translating the image of the light flux, for example the image of the [ Fig.1 - to the right when the vehicle turns right or to the left when the vehicle turns left - so that the light beam is shifted to the right or left. Another current DBL technique involves compressing one side of the light beam image and decompressing the other side of said image so as to shift the light beam to the right or left.

[0006] Both of these current techniques have the effect of preserving the same image of the luminous flux, shifted to the right or to the left. However, in certain circumstances, it may be advantageous to modify the luminous intensity, for example to make the maximum luminous intensity higher or, conversely, lower, which cannot be achieved by simply shifting the image of the luminous flux to one side or the other.

[0007] Furthermore, new regulations impose specific characteristics for right-hand lighting and other specific characteristics for left-hand lighting, characteristics that current DBL techniques cannot satisfy.

[0008] Document EP 3 672 369 A1 is representative of prior art. Summary of the invention

[0009] To address the problems mentioned above due to the shift of the luminous flux image to the right or to the left, and to comply with the new regulations, the applicant proposes a method for controlling directional lighting in which at least three different initial images of the luminous flux are taken, from which intermediate images of the luminous flux can be determined by applying a weighted average.

[0010] According to a first aspect, the invention relates to a method of controlling directional lighting by a vehicle lighting device emitting, in the direction of a road scene, a luminous flux varying according to the movement of the vehicle, the method comprising the following operations: a) determination of at least three initial images of the luminous flux corresponding to three predefined directions, each initial image of the luminous flux corresponding to a light emission by the lighting device in a predefined direction, d) when the vehicle does not follow one of the predefined directions, determination of an intermediate image of the luminous flux to be emitted by the lighting device in an intermediate direction, by a weighted average of two of the three initial images of the luminous flux corresponding to the directions framing the intermediate direction most closely; and e) projection, onto the road scene, according to the direction of movement of the vehicle, of the initial or intermediate image of the luminous flux.

[0011] This process makes it possible to determine an image of the specific luminous flux for each direction taken by the vehicle between the leftmost direction and the rightmost direction.

[0012] Advantageously, the three initial images of the luminous flux include: an initial left lateral image of the luminous flux emitted by the lighting device towards the left of the vehicle, an initial right lateral image of the luminous flux emitted by the lighting device towards the right of the vehicle, and an initial central image of the luminous flux emitted by the lighting device towards the center of the vehicle.

[0013] With these three images, it is possible to determine an intermediate image of the light flux between the initial left-hand side image and the initial central image, for all vehicle directions between the leftmost direction and the central direction, and an intermediate image of the light flux between the initial central image and the initial right-hand side image, for all vehicle directions between the central direction and the rightmost direction. Thus, a light flux image suitable for any direction of vehicle travel can be projected onto the road, the direction of travel being any direction within the range of possible directions between the maximum left-hand and maximum right-hand turning angles permitted by the vehicle.The driver of the vehicle therefore sees an optimally lit road scene continuously throughout the journey and regardless of the vehicle's trajectory.

[0014] By definition, an "initial image" is a predetermined image of the luminous flux, corresponding to a predefined direction and / or a particular DBL angle. By extension, a predefined direction is also called the "initial direction" and a particular DBL angle is also called the "initial DBL angle," as opposed to the DBL angle of the moving vehicle.

[0015] In addition to the characteristics mentioned in the preceding paragraph, the method for controlling directional lighting according to one aspect of the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: It includes, prior to operation d) of determining an intermediate image of the luminous flux: a first operation c1) of translating a first initial image of the luminous flux corresponding to one of the two directions framing the intermediate direction most closely, and a second operation c2) of translating a second initial image of the luminous flux corresponding to the other of the directions framing the intermediate direction most closely, the first translation operation c1) being carried out in the opposite direction to that of the second translation operation c2). It includes an operation b) of determining a proportional positioning of the intermediate image between a first initial image of the luminous flux and a second initial image of the luminous flux, a positioning coefficient being deduced from said proportional positioning.The positioning coefficient is applied to operations c1) and c2) of translating the first and second initial images of the luminous flux. The positioning coefficient is applied to operation d) of weighted averaging of the two initial images of the luminous flux.

[0016] According to a second aspect, the invention relates to a directional vehicle lighting device emitting a luminous flux to illuminate a road scene according to the movement of said vehicle, characterized in that it implements the method as defined above.

[0017] Advantageously, this lighting device comprises a plurality of light-emitting diodes, aligned or in the form of a screen, whose luminous power varies so as to generate at least three initial images of luminous flux. BRIEF DESCRIPTION OF THE FIGURES

[0018] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: There [ Fig.1 ], already described, represents an example of a luminous flux image classically used in DBL systems; The [ Fig. 2 ] represents, in the form of a functional diagram, an example of the different operations of the process according to the invention; The [ Fig.3 ] represents examples of initial images of the luminous flux produced in the process according to the invention; The [ Fig. 4 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is 0°; The [ Fig. 5 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is 100°; The [ Fig. 6 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is -100°; The [ Fig. 7 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is +40°; The [ Fig. 8 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is +80°; and La [ Fig. 9 ] represents different images of the luminous flux used in the process according to the invention when the DBL angle is -60°. DETAILED DESCRIPTION

[0019] An example of a method for controlling directional lighting using a vehicle headlight is described in detail below, with reference to the accompanying drawings. This example illustrates the features and advantages of the invention. It should be noted, however, that the invention is not limited to this example.

[0020] In the figures, identical elements are identified by identical references. For the sake of readability, the size scales between represented elements are not respected.

[0021] An example of the method 100 according to the invention is shown, in functional form, on the [ Fig. 2 This process includes a first operation 110 of creating the initial images of the light flux. These initial images of the light flux, more simply called initial images, are the images of the light flux emitted by the vehicle's headlights when the vehicle is moving along predefined directions. There are at least three initial images, each corresponding to a different predefined direction.

[0022] Examples of three initial images are shown on the [ Fig.3 ]. In the example of the [ Fig.3The initial image IM1 represents an example of luminous flux for a vehicle traveling in a straight line, that is, along a rectilinear path. When the vehicle travels in a straight line, the angle DBL corresponding to the direction followed by the vehicle is equal to 0. The initial image IM1 for a vehicle moving in a straight line is called the central initial image.

[0023] In the example of the [ Fig.3 The initial image IM2 represents an example of luminous flux for a vehicle turning fully to the right, that is, following a curved trajectory oriented fully to the right. When the vehicle turns fully to the right, i.e., when the steering wheel angle is at its maximum rightward angle, the angle DBL is considered equal to +100°. The initial image IM2 for a vehicle turning fully to the right is called the right lateral initial image.

[0024] In the example of the [ Fig.3The initial image IM3 represents an example of luminous flux for a vehicle turning fully to the left, that is, following a curved trajectory oriented fully to the left. When the vehicle turns fully to the left, that is, when the steering wheel angle is at its maximum leftward, the angle DBL is considered equal to -100°. The initial image IM3 for a vehicle turning fully to the left is called the left lateral initial image.

[0025] The three initial images IM1, IM2, and IM3 are predefined images that meet regulatory requirements. These three images, IM1, IM2, and IM3, are determined by the lighting device manufacturer and implemented in said lighting device prior to the vehicle's registration or during updates to said lighting device by a professional.

[0026] The number three initial images is the minimum number required to implement the method of the invention. The number of initial images may be greater than three, for example, five. When there are three initial images, these images preferably comprise the left lateral initial image IM3, the right lateral initial image IM2, and the central initial image IM1. When more than three initial images are embedded in the lighting device, then the two additional images beyond IM1, IM2, and IM3 may be intercalated images, positioned between the central initial image IM1 and, respectively, the left lateral initial images IM3 and the right lateral initial images IM2, corresponding, for example, to a DBL angle of +50° and -50°. Regardless of the number of initial images, the method 100 will be applied in the same way as explained below.

[0027] After acquiring the initial images IM1, IM2, and IM3, process 100, in test 120, verifies whether the vehicle's DBL angle corresponds to one of the predefined initial directions. In other words, process 100 checks if the vehicle's DBL angle corresponds to one of the initial DBL angles for which an initial image has been determined. If so, the process continues with operation 130, during which the initial image of the luminous flux corresponding to the initial DBL angle is projected onto the road scene. For example, if test 120 determines that the vehicle's DBL angle corresponds to the initial DBL angle + 100, then the initial image IM2 is projected onto the road.

[0028] Conversely, if the vehicle's DBL angle does not correspond to one of the initial DBL angles, then the process continues in step 140, which determines the initial directions that most closely bracket the vehicle's DBL angle. In other words, step 140 determines which initial DBL angles bracket the moving vehicle's DBL angle. For example, if the vehicle's DBL angle is +40°, then the initial DBL angles bracketing this DBL + 40° angle are DBL + 100° and DBL 0°. As another example, if the vehicle's DBL angle is -60°, then the initial DBL angles bracketing this DBL -60° angle are DBL - 100° and DBL 0°.

[0029] Process 100 then continues in steps 150 and 160, which translate the initial images. In step 150, the initial image corresponding to the right-hand initial DBL angle—that is, the image whose value is greater than the vehicle's DBL angle (the right-hand side of the vehicle's DBL angle)—is translated to the left. In step 160, the initial image corresponding to the left-hand initial DBL angle—that is, the image whose value is less than the vehicle's DBL angle (the left-hand side of the vehicle's DBL angle)—is translated to the right. For example, for a vehicle DBL angle of +40°, the right-hand lateral initial image IM2 (corresponding to DBL angle +100°) is translated to the left, and the central initial image IM1 (corresponding to initial DBL angle 0°) is translated to the right.According to another example, where the vehicle's DBL angle is equal to -60, the initial left lateral image IM3 (corresponding to the DBL angle -100) is translated to the right and the initial central image IM1 (corresponding to the initial DBL angle 0) is translated to the left.

[0030] Translation steps 150 and 160 are preferably applied using a positioning coefficient determined from the proportional positioning of the vehicle's DBL angle relative to the nearest initial DBL angles. Indeed, step 140 of the process can incorporate an operation to determine the proportional positioning of the intermediate image between the first initial image, for example, the initial image corresponding to the right-hand initial DBL angle, and the second initial image, for example, the initial image corresponding to the left-hand initial DBL angle. A positioning coefficient is then derived from this proportional positioning.

[0031] For example, with a vehicle DBL angle of +40, the positioning coefficient is 40 / 60; the central initial image IM1 is shifted 40 to the right and the right lateral initial image IM2 is shifted 60 to the left, where 40 and 60 are proportional numbers, for example, expressed as percentages or as a number of pixels. In another example, with a vehicle DBL angle of -60, the positioning coefficient is 60 / 40; the central initial image IM1 is shifted 60 to the left and the left lateral initial image IM3 is shifted 40 to the right.

[0032] Following steps 150 and 160, the two initial images, for example IM1 / IM2 or IM1 / IM3, corresponding to the initial DBL angles closest to the vehicle's DBL angle are superimposed.

[0033] Process 100 continues in step 170, during which a weighted average of the two translated initial images is applied. The averaging of these two initial images is performed by weighting each image according to the positioning coefficient used in steps 150 and 160. For example, for a vehicle DBL angle of +40°, the weighting for the central initial image IM1 is 40% and that for the right lateral initial image IM2 is 60%. In the example where the vehicle DBL angle is -60°, the weighting of the central initial image IM1 is 60% and that of the left lateral initial image IM3 is 40%. In the example where the vehicle DBL angle is -20°, the weighting of the central initial image IM1 is 20% and that of the left lateral initial image IM3 is 80%.

[0034] The operation of averaging the two initial translated images is carried out, for example, pixel by pixel or by any other image averaging technique known in the field of image processing.

[0035] The image Im4 obtained after applying the weighted average to the two initial translated images is called the intermediate image of the light flux, or simply the intermediate image. This intermediate image Im4 is then projected, at step 180, onto the road.

[0036] Several examples of initial and / or intermediate images are shown on the figures 4 to 9 In all these examples, the number of initial images is three: The initial image shown in A is the left lateral initial image, corresponding to the initial DBL angle -100 (or leftmost DBL angle); the initial image shown in B is the central initial image, corresponding to the initial DBL angle 0, i.e. the central DBL angle; the initial image shown in C is the right lateral initial image, corresponding to an initial DBL angle +100 (or rightmost DBL angle); and the image shown in D is the resulting image (i.e. the initial image or the intermediate image as the case may be) which will be projected onto the road.

[0037] In these examples of figures 4 to 9 The numbers in pixels (px) correspond to the positioning coefficients applied to the translation of the initial images to be translated, and the numbers in percentages (%) correspond to the weighting applied during the averaging of the translated initial images. The initial images A, B, or C of the figures 4 to 9, which are not associated with a number of pixels, are initial images not used for determining the image D to be projected.

[0038] In the example of the [ Fig. 4 ], the angle DBL of the vehicle is the initial angle DBL 0. The image D to be projected is therefore the initial central image (image B).

[0039] In the example of the [ Fig. 5 ], the vehicle's angle DBL is the initial angle DBL +100. The image D to be projected is therefore the initial right lateral image (image C).

[0040] In the example of the [ Fig. 6 ], the vehicle's angle DBL is the initial angle DBL -100. The image D to be projected is therefore the initial left lateral image (image A).

[0041] In the example of the [ Fig. 7The vehicle's DBL angle is the intermediate angle +40. The initial images to be translated are therefore the central initial image (image B), which is translated by +40px (i.e., 40px to the right), and the right lateral initial image (image C), which is translated by -60px (i.e., 60px to the left). The image D to be projected is thus the intermediate image obtained by averaging image B with a weighting of 60% and image C with a weighting of 40%.

[0042] In the example of the [ Fig. 8The vehicle's DBL angle is the intermediate angle +80. The initial images to be translated are therefore the central initial image (image B), which is translated by +80px (i.e., 80px to the right), and the right lateral initial image (image C), which is translated by -20px (i.e., 20px to the left). The image D to be projected is thus the intermediate image obtained by averaging image B with a weighting of 20% and image C with a weighting of 80%.

[0043] In the example of the [ Fig. 9The vehicle's DBL angle is the intermediate angle -60. The initial images to be translated are therefore the left lateral initial image (image A), which is translated by +40px (i.e., 40px to the right), and the central initial image (image B), which is translated by -60px (i.e., 60px to the left). The image D to be projected is thus the intermediate image obtained by averaging image A with a weighting of 60% and image B with a weighting of 40%.

[0044] The 100 procedure was previously described using examples where three initial images, Im1, Im2, and Im3, were determined. It should be understood that the same procedure applies regardless of the number of initial images determined. If more than three initial images are determined, the initial images to be translated and averaged are the two initial images corresponding to the two initial DBL angles that most closely bracket the vehicle's DBL angle. For example, if five initial images were determined for initial DBL angles of +0, +50, +100, -50, and -100, and if the vehicle's DBL angle is +20, then the initial images to be translated and averaged are the initial image corresponding to the initial DBL angle +0 and the initial image corresponding to the initial DBL angle +50.

[0045] The process as described above can be implemented in many types of lighting devices, such as matrix, laser-scanning, LED or micro-LED displays, etc., provided that the emitted light output can be varied. For example, in an LED lighting device, the power of each LED is controlled, for instance by a control unit, so that different initial images of the luminous flux can be generated for different initial DBL angles.

[0046] Although described through a number of examples, variants and embodiments, the method of controlling directional lighting according to the invention includes various variants, modifications and improvements which will be obvious to a person skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention.

Claims

1. A method (100) for controlling bending light generated by a vehicle lighting device emitting, toward a road scene, a luminous flux that varies depending on the movement of the vehicle, characterized in that the method comprises the following steps: - a) determining (110) at least three initial luminous-flux images (Im1, Im2, Im3) corresponding to three predefined directions, each initial luminous-flux image corresponding to emission of light by the lighting device in a predefined direction, - d) when the vehicle is not following one of the predefined directions, determining an intermediate luminous-flux image (Im4) to be emitted by the lighting device in an intermediate direction, by weighted averaging (170) of two of the three initial luminous-flux images (Im1, Im2, Im3) corresponding to the directions flanking the intermediate direction most closely; and - e) projecting (130, 180), onto the road scene, depending on the direction of movement of the vehicle, the initial or intermediate luminous-flux image.

2. The method as claimed in claim 1, characterized in that the three initial luminous-flux images comprise: - a left lateral initial luminous-flux image (lm3) emitted by the lighting device toward the left of the vehicle, - a right lateral initial luminous-flux image (lm2) emitted by the lighting device toward the right of the vehicle, and - a central initial luminous-flux image (Im1) emitted by the lighting device toward the center of the vehicle.

3. The method as claimed in claim 1 or 2, characterized in that it comprises, prior to operation d) of determining an intermediate luminous-flux image: - a first operation c1) of translating (150) a first initial luminous-flux image corresponding to one of the two directions flanking the intermediate direction most closely, and - a second operation c2) of translating (160) a second initial luminous-flux image corresponding to the other of the directions flanking the intermediate direction most closely, the first translating operation c1) being carried out in a direction opposite to that of the second translating operation c2).

4. The method as claimed in any one of claims 1 to 3, characterized in that it comprises an operation b) of determining a proportional position of the intermediate image between a first initial luminous-flux image and a second initial luminous-flux image, a positioning coefficient being deduced from said proportional position.

5. The method as claimed in claims 3 and 4, characterized in that the positioning coefficient is applied in operations c1) and c2) of translating (150, 160) the first and second initial luminous-flux images.

6. The method as claimed in claim 4 or 5, characterized in that the positioning coefficient is applied in operation d) of weighted averaging (170) of the two initial luminous-flux images.

7. A vehicle bending-light lighting device emitting a luminous flux to illuminate a road scene depending on the movement of said vehicle, characterized in that it implements the method as claimed in any one of the preceding claims.

8. The lighting device as claimed in claim 7, characterized in that it comprises a plurality of light-emitting diodes, aligned or taking the form of a screen, the luminous power of which varies so as to generate at least three initial luminous-flux images (Im1, Im2, Im3).