METHOD FOR CONTROLLING A LIGHTING DEVICE SUITABLE FOR EMITTING TWO PIXELATED LIGHT BEAMS WITH DIFFERENT RESOLUTIONS

Abstract

The invention relates to a method for controlling a lighting device for a motor vehicle comprising at least first and second light modules arranged to emit, respectively, first and second pixelated light beams in first and second predetermined emission zones which are associated with them, the resolution of the first pixelated light beam being greater than the resolution of the second pixelated light beam and the first and second predetermined emission zones being adjacent, the method includes detecting the presence of a target object in a given zone among the first and second predetermined emission zones and forming a dark zone in the pixelated light beam associated with the given zone, by extinction or attenuation of at least one pixel of the pixelated light beam, located at the level of the target object.

Claims

1. A method for controlling a device for a motor vehicle comprising at least first and second light modules arranged to respectively emit first and second pixelated light beams in first and second predetermined emission zones that are associated with them, the resolution of the first pixelated light beam being greater than the resolution of the second pixelated light beam and the first and second predetermined emission zones being adjacent, the method comprising: detecting the presence of a target object in a given zone from among the first and second predetermined emission zones; forming a dark zone in the pixelated light beam associated with the given zone, by extinguishing or attenuating at least one pixel of the first pixelated light beam, located at the level of the target object; progressively modifying at least one first pixel of the second pixelated light beam when the target object moves from the given zone toward an other zone of the first and second predetermined emission zones and before the target object reaches the other zone.

2. The method as claimed in claim 1, wherein the step of progressive modification includes defining an attenuation mask, the attenuation mask moving concomitantly with the target object, and modifying the first pixel of the second pixelated light beam when a cell of the attenuation mask is adjacent to this first pixel.

3. The method as claimed in claim 2, wherein the values of the cells of the attenuation mask define an attenuation gradient, and wherein the first pixel is modified in accordance with the value of the cell adjacent to this first pixel.

4. The method as claimed in claim 3, wherein the gradient defined by the values of the cells is a symmetrical horizontal gradient, the minimum of which is located at the center of the attenuation mask.

5. The method as claimed in claim 2, wherein the horizontal dimension of the attenuation mask is greater than or equal to the width of the target object.

6. The method as claimed in claim 2, wherein the vertical resolution of the attenuation mask is substantially identical to that of the second pixelated beam.

7. The method as claimed in claim 1, wherein the dark zone, when it is formed in the first pixelated light beam, is produced by attenuating a predetermined number of pixels in a zone centered on the target object.

8. The method as claimed in claim 2, wherein the horizontal resolution of the attenuation mask is determined as a function of the number of values adopted by the pixels of the dark zone of the first pixelated light beam.

9. The method as claimed in claim 1, further comprising progressively modifying at least one second pixel of the second pixelated light beam when the target object moves from the first pixel toward said a second pixel and before the target object reaches the second pixel, when the given zone is the second predetermined zone.

10. The method as claimed in claim 1, wherein the first pixelated light beam is a light beam comprising a plurality of pixels distributed over a plurality of rows and columns and wherein the second pixelated light beam is a light beam comprising a plurality of pixels distributed over a single row.

11. A computer program comprising a program code that is designed to implement the method as claimed in claim 1.

12. A data medium, on which the computer program as claimed in claim 11 is recorded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will now be described with reference to examples that are only illustrative and in no way limit the scope of the invention, and with reference to the accompanying illustrations, in which:

[0032] FIG. 1 schematically and partially shows a lighting device for implementing a method according to one embodiment of the invention;

[0033] FIG. 2 schematically shows a projection on a screen of the light beams emitted by the lighting device of FIG. 1;

[0034] FIG. 3 shows a method for controlling the lighting device of FIG. 1 according to one embodiment of the invention;

[0035] FIG. 4 schematically shows a projection on a screen of the pixelated beams emitted by the device of FIG. 1 at a given instant of the implementation of the method of FIG. 3;

[0036] FIG. 5 schematically shows a projection on a screen of the pixelated beams emitted by the device of FIG. 1 at another given instant of the implementation of the method of FIG. 3;

[0037] FIG. 6 schematically shows a projection on a screen of the pixelated beams emitted by the device of FIG. 1 at another given instant of the implementation of the method of FIG. 3;

[0038] FIG. 7 schematically shows a projection on a screen of the pixelated beams emitted by the device of FIG. 1 at another given instant of the implementation of the method of FIG. 3;

[0039] FIG. 8 shows an example of a blur mask used in the method of FIG. 3; and

[0040] FIG. 9 shows an example of an attenuation mask used in the method of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0041] In the following description, elements that are identical in terms of structure or in terms of function and that appear across various figures use the same reference signs, unless otherwise indicated.

[0042] FIG. 1 shows a right-hand side lighting device 1 of a host motor vehicle, comprising three light modules 2, 3 and 4. The light module 2 comprises a light source 21 associated with a lens 22 for emitting a light beam of the low beam LB type. The light module 3 comprises a pixelated light source 31 associated with a lens 32 for emitting a first pixelated light beam HD and the light module 4 comprises a matrix of LEDs 41 associated with a lens 42 for emitting a second pixelated beam LD. In the example described, the pixelated light source 31 is a monolithic pixelated light-emitting diode, each of the light-emitting elements of which forms a light source that is able to be selectively activated and controlled by an integrated controller in order to emit an elementary light beam, the light intensity of which is able to be controlled, and thus forming one of the pixels of the pixelated light beam HD. The lighting device 1 comprises a controller 5 arranged to control the light source 21, the controller integrates the pixelated light source 31 and the LEDs of the matrix of LEDs 41 so as to selectively control the illumination, the extinction and the modification of the light intensity of each of the pixels of the pixelated light beams HD and LD, as well as the illumination or the extinction of the beam LB, as a function of information received from a computer 6 of the host vehicle, in order to implement an anti-dazzle high beam lighting function. These light beams LB, HD and LD are shown in FIG. 2 projected onto a screen when they are emitted simultaneously.

[0043] In the example described, the first pixelated light beam HD is emitted in a first emission zone ZHD and comprises 88 pixels HDi,j of dimensions 0.2°, distributed over 8 columns and 11 rows. The second pixelated light beam LD is emitted in a second emission zone ZLD and comprises 4 pixels LDi of dimensions 1°, distributed over a single row. As shown in FIG. 2, the resolution of the first pixelated beam HD, and in particular its vertical resolution, is therefore higher than the resolution of the second pixelated beam LD. Furthermore, the first emission zone ZHD is adjacent to the second emission zone ZLD. Indeed, the pixels HD1,1 to HD1,11 of the first pixelated light beam HD located at the edge of the first emission zone ZHD and on the side of the second emission zone ZLD are juxtaposed and in contact with the first pixel LD1 of the second pixelated light beam LD located at the edge of the second emission zone ZLD and on the side of the first emission zone ZHD. Finally, the emission zones ZLD and ZHD extend above an upper cut-off line of the low beam LB so as to cover a road scene on which a target motor vehicle C is travelling. The first emission zone ZHD thus extends over a central portion of the road scene, whereas the second zone ZLD extends over a lateral portion of the road scene. The embodiment described in FIG. 2 does not mention a pixelated light beam on the other side of the first pixelated beam HD, but such a beam could be provided symmetrical to the second pixelated beam LD without departing from the scope of the present invention.

[0044] A method for controlling the lighting device 1 according to one embodiment of the invention, implementing an anti-dazzle high beam lighting function, is shown in FIG. 3, and the various stages of which will now be described with reference to FIG. 4 to FIG. 7, which show the pixelated light beams HD and LD projected onto a screen during these various steps.

[0045] The control method comprises a first step E1 of detecting the presence of the target vehicle C and of determining the position of the target object C on the road. This step E1 can be implemented, for example, by one or more sensors of the host vehicle, such as, for example, a camera and/or a radar and/or a lidar, associated with the computer 6 of the host vehicle implementing image or signal processing algorithms. On completion of step E1, the computer 6 notifies the controller 5 of the presence of the target object C and provides its position.

[0046] The method comprises a second step E2 of forming a dark zone ZS in one and/or the other of the pixelated beams HD and LD as a function of said position of the target object C. In the example described, the target object C is located in the first emission zone ZHD associated with the first pixelated beam HD. The controller 5 will thus initially define a blur mask MF comprising 20 cells divided into 4 columns and 5 rows and the dimensions of which correspond to the pixels HDi,j of the first pixelated beam HD and the values of which define a radial gradient, the minimum of which is located at the center of the mask MF. An example of a blur mask MF is shown in FIG. 8. The radial gradient of this example of a blur mask MF defines 4 values that can be adopted by the pixels HDi,j of the first pixelated beam, namely 0%, 25%, 50%, 75% of a maximum intensity value that can be adopted by these pixels, with the 0% values being located at the center of the mask and the 75% values being located at the corners of the mask. These values have been shown in FIG. 8 using various distributions of dotted lines.

[0047] Secondly, the controller 5 will apply the blur mask MD to the pixels HDi,j of the first pixelated beam HD by centering the blur mask MD on the position of the target object C. Each affected pixel HDi,j thus will be switched off or attenuated, so that its light intensity corresponds to the value of the corresponding cell of the blur mask MF, with the other unaffected pixels HDi,j being kept on, so as to form the dark zone ZS. All the pixels LDi are also kept on. The beam resulting from the combination of the beams HD and LD therefore illuminates the road ahead of the host vehicle as much as possible, without dazzling the driver of the target vehicle C.

[0048] During a third step E3, the controller 5 will also define an attenuation mask MA and overlay this attenuation mask MA with the position of the target object C. The attenuation mask MA comprises 44 cells divided into as many rows as the second pixelated beam LD comprises, in this case a single row with the same dimensions as those of the rows of the second pixelated beam LD, and into as many columns as the number of values defined by the gradient of the blur mask, in this case four columns with the same dimensions as those of the columns of the first pixelated beam HD. The values of the cells of the attenuation mask MA define an asymmetrical horizontal gradient, the minimum of which is located at an edge of the mask MA. An example of an attenuation mask MA is shown in FIG. 9.

[0049] As will be described hereafter, during a step E4, the controller 5 will modify the value of at least the first pixel LD1 of the second pixelated beam LD as a function of the position of this attenuation mask MA with respect to the second emission zone ZLD. Indeed, the attenuation mask MA is centered on the position of the target vehicle C and moves concomitantly therewith. The first pixel LD1 thus will be modified by the controller 5 when a cell of the attenuation mask MA is adjacent to this first pixel LD1.

[0050] At the time of FIG. 4, the attenuation mask MA is remote from the first pixel LD1. Therefore, there is no need to change the intensity of this first pixel LD1.

[0051] At the time of FIG. 5, the target vehicle C has moved along the road scene in order to approach and pass the host vehicle. The blur mask MF has also moved in order to remain centered on the position of the target vehicle C, so that the dark zone ZS remains at the level of the target vehicle C to avoid dazzling said vehicle. At this time, the target vehicle C nevertheless has not reached the second emission zone ZLD. However, a cell C1 of the attenuation mask MA is now adjacent to the first pixel LD1 of the second pixelated beam LD. The controller 5 will thus modify the light intensity of the first pixel LD1 so that this light intensity corresponds to the value of the cell C1. Thus, it can be seen that the first pixel LD1 attenuates before the target vehicle C has reached the second emission zone ZLD.

[0052] At the time of FIG. 6, the target vehicle C has still moved along the road scene toward the host vehicle, yet without reaching the second emission zone ZLD. The blur mask MF thus has moved in order to follow the position of the target vehicle, and has reached the edge of the first emission zone ZHD. A smaller number of pixels of the first pixelated beam HD was thus affected by the mask MF in order to define the dark zone ZS. Furthermore, a second cell C2 of the attenuation mask MA is now adjacent to the first pixel LD1 of the second pixelated beam LD, which implies that the controller 5 will again modify the light intensity of this first pixel LD1 according to the value of this second cell C2. Due to the horizontal gradient defined by the attenuation mask MA, the attenuation of the first pixel LD1 is higher, despite the fact that the target vehicle C still has not reached the second emission zone ZLD.

[0053] At the time of FIG. 7, the target vehicle C has moved and has reached the second emission zone ZLD. The light intensity of the first pixel LD1 is thus again attenuated by the controller 5 according to the value of the cell C3 of the attenuation mask MA adjacent thereto, whereas the number of pixels HDi,j switched off or attenuated in order to form the dark zone ZS in the first pixelated light beam HD continues to decrease. Furthermore, the cell C1 of the attenuation mask MA is now adjacent to the second pixel LD2 of the second pixelated beam LD, so that the controller 5 also attenuates the light intensity of this second pixel according to the value of the cell C1.

[0054] Thus, it is understood that the pixel LD1 thus experiences progressive attenuation of its light intensity when the target vehicle C transitions from the first emission zone ZHD toward the second emission zone ZLD. This transition will conclude in a step E5, not shown, with the removal of the dark zone ZS in the first pixelated beam HD, with all the pixels HDi,j being illuminated, and with the complete extinction of the pixel LD1 of the second pixelated beam LD in order to form a dark zone in this second pixelated beam at the level of the target vehicle C. Furthermore, the light intensity of the second pixel LD2 will be progressively attenuated in order to prepare for the transition of the target vehicle C from the first pixel LD1 toward the second pixel LD2.

[0055] The description of the method according to this embodiment was provided for a transition of the target vehicle C from the first emission zone ZHD toward the second emission zone ZLD. It is obvious that this method can be applied in the same manner for a transition of the target vehicle C from the second emission zone ZLD toward the first emission zone ZHD, for example, when the target vehicle C is a followed vehicle or a vehicle performing an overtaking maneuver, by enhancing the light intensity of the first pixel LD1 before the target vehicle has reached the first emission zone ZHD.

[0056] The above description clearly explains how the invention allows its stated objectives to be achieved, and in particular by proposing a method for controlling a hybrid lighting device emitting two pixelated light beams with different resolutions, which, by progressively modifying a pixel of one of the pixelated light beams before a target object has reached the emission zone of this beam, enables a dark zone located at the level of the target object to smoothly transition from the other one of the beams toward this beam.

[0057] In any event, the invention should not be regarded as being limited to the embodiments specifically described in this document, and in particular it extends to any equivalent means and any technically operative combination of these means. In particular, other types of attenuation mask can be contemplated by varying its dimensions or the values of its cells. The use of an attenuation mask without a blur mask also can be contemplated. Finally, other embodiments of a progressive transition can be contemplated that implement, for example, a prediction of the trajectory of the target vehicle and a progressive modification of the intensity of the first pixel of the second pixelated light beam as a function of said predicted trajectory.