METHOD FOR DISTINGUISHING A SECONDARY LANE MARKING FROM A PRIMARY LANE MARKING

Description

[0001] The present invention relates to a method for differentiating secondary road markings on a road, on which a vehicle is located, from primary road markings on said road. It finds particular, but not limited, application in motor vehicles. It also relates to a differentiation device for implementing said differentiation method.

[0002] In the field of motor vehicles, there are methods for detecting road markings which include: the lighting at the front of the motor vehicle of said road by a primary camera, the acquisition by said primary camera of images of said road marking at the front of said motor vehicle, the detection by the primary camera of the road marking of said road in front of the motor vehicle, the detection by a secondary camera of the road marking of said road laterally to the motor vehicle, the execution of a determined function according to said detected road marking.

[0003] Depending on the application for which the detection process is used, the specific function that is executed is, for example: a function to assist said motor vehicle in parking, or a function to assist said motor vehicle in changing lanes, or to assist it in staying in a lane.

[0004] The secondary camera is an infrared or near-infrared camera, as infrared light is invisible to the naked eye. This ensures compliance with current regulations that prohibit the use of cameras that illuminate the side of a vehicle using visible light. Therefore, pedestrians or vehicles on the side of the vehicle are not dazzled or disturbed by visible light.

[0005] One drawback of this prior art is that the secondary camera, which is infrared or near-infrared, cannot differentiate between colors. Therefore, if there are sections of road under construction where there is a primary road marking, typically white (the standard road marking), and a secondary road marking, typically yellow (the temporary road marking), the secondary camera cannot distinguish between these two types of road markings, and the road marking detection process cannot function correctly. Consequently, it is unclear which road marking to follow to perform the intended function. JP 2012 037312 A describes an on-board system using a single camera to detect a first road marking and a second marking of the same shape, and then differentiate them based on their relative position (front / back and left / right distances).It compares the observed geometric relationship with a database of predefined relationships to identify the correct marking among several similar ones. The goal is to enable the correct determination of the relevant lane or marking even when multiple identical markings are present.

[0006] In this context, the present invention aims to propose a method for differentiating a secondary road marking on a road on which a vehicle is located from a primary road marking of said road which makes it possible to resolve the inconvenience mentioned according to the attached claims.

[0007] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures: Fig. 1a is a flowchart of a method for differentiating a secondary road marking on a road on which a vehicle is located from a primary road marking of said road, according to a first non-limiting embodiment of the invention, Fig. 1b is a flowchart of a method for differentiating a secondary road marking on a road on which a vehicle is located from a primary road marking of said road, according to a second, non-limiting embodiment of the invention, Fig. 2 is a schematic top view of a vehicle located on a road comprising primary and secondary road markings, according to a non-limiting embodiment, Fig. 3 is a schematic view of a device for differentiating a secondary road marking on a road on which a vehicle is located from a primary road marking of said road, said device enabling the implementation of the differentiation process of figures 1a And 1b , according to a non-limiting embodiment, Fig. 4a is a schematic top view of the vehicle of the figure 2 said view comprising points on the primary and secondary ground markings used to determine the position of one ground marking relative to the other, according to a first non-limiting embodiment, Fig. 4b is a schematic top view of a primary image acquired by a primary camera of the differentiation device of the figure 3 said primary image comprising the points on the primary ground marking and on the secondary ground marking of the figure 4a , according to a first, non-limiting embodiment, Fig. 5a is a schematic top view of the vehicle of the figure 2 said view comprising points on the primary and secondary ground markings used to determine the position of one ground marking relative to the other, according to a second, non-limiting embodiment, Fig. 5b is a schematic top view of a primary image acquired by a primary camera of the differentiation device of the figure 3 said primary image comprising the points on the primary ground marking and on the secondary ground marking of the figure 5a , according to a second, non-limiting embodiment, Fig. 6 is a flowchart of a method for positioning a vehicle in relation to a secondary road marking of a road on which a vehicle is located from a primary road marking of said road, according to a non-limiting embodiment.

[0008] Identical elements, whether structural or functional, appearing on different figures retain the same references unless otherwise specified.

[0009] The method for differentiating 1 a secondary road marking M2 of a road R1 on which a vehicle 5 is located from a primary road marking M1 of said road R1, according to the invention, is described with reference to figures 1 à 5b In a non-limiting embodiment, vehicle 5 is a motor vehicle. A motor vehicle is defined as any type of motorized vehicle. This embodiment is taken as a non-limiting example in the following description. In the following description, vehicle 5 is thus also referred to as motor vehicle 5. Motor vehicle 5 has a width L1*2 (as illustrated in the diagram). figures 2 , 4a And 5a) and has a length that extends along a longitudinal axis Ax perpendicular to a transverse axis Ay and passing through its midpoint.

[0010] The differentiation process 1 is implemented by a differentiation device 3 illustrated on the figure 3 which includes: a primary camera 31, and at least one secondary camera 32, and an electronic control unit 33.

[0011] The primary camera 31 is located at the front or rear of the motor vehicle 5, while at least one secondary camera 32 is located on one side of the motor vehicle 5. As illustrated in the non-limiting example of the figure 2 The primary camera 31 is located at the front of the motor vehicle 5. In a non-limiting embodiment, it is positioned behind the windshield at the level of the rearview mirror. The primary camera 31 is a camera that operates in the visible spectrum. The primary camera 31 is configured to acquire RGB color images of the exterior of the motor vehicle 5.

[0012] As illustrated in the non-limiting example of the figure 2 The secondary camera 32 is located on the left side of the motor vehicle 5. In a non-limiting embodiment, it is arranged in a side mirror. In other non-limiting embodiments, the secondary camera 32 is an infrared camera (wavelength between 700 nanometers and 1 millimeter), a near-infrared camera (wavelength of approximately 850 nanometers), a long-wave infrared (LWIR) camera (wavelength of approximately 10 micrometers), or a short-wave infrared (SWIR) camera (wavelength of approximately 1 micrometer). The secondary camera 32 is configured to acquire infrared images of the exterior of the motor vehicle 5.

[0013] In a non-limiting embodiment, the electronic control unit 33 is part of the primary camera 31 or is remote from said primary camera 31. In a non-limiting embodiment not shown, the differentiation device 3 comprises a secondary camera 32 located on each side of the motor vehicle 5, one on the left side and one on the right side.

[0014] The differentiation process 1 makes it possible to differentiate a secondary road marking M2 from a primary road marking M1 on a road R1 on which the motor vehicle 5 is located. As illustrated on the figure 2 The primary road marking M1 represents the standard road marking of an R1 road, while the secondary road marking M2 represents the road marking related to roadworks on the R1 road. Thus, the primary road marking M1 is permanent, while the secondary road marking M2 is temporary. The primary road marking M1 has a primary color C1 and the secondary road marking M2 has a secondary color C2. The two colors C1 and C2 are different. Thus, in a non-limiting example, the primary color C1 is white (illustrated in dark color on the figure 2 ) while the secondary color C2 is yellow (illustrated in a lighter color on the figure 2 ).

[0015] To differentiate secondary road marking M2 from primary road marking M1, the differentiation process 1 comprises the following steps as illustrated in the figure 1a according to a first, non-limiting embodiment. It should be noted that some steps are carried out in parallel.

[0016] In a first step E1, illustrated F1(31, I1) on the figure 1a The primary camera 31 acquires primary images I1 of the external environment in front of or behind said motor vehicle 5. The primary images I1 thus include images of said primary road marking M1 and said secondary road marking M2 located in front of or behind said motor vehicle 5. As illustrated in the non-limiting example of the figure 2 The primary I1 images acquired are those of the external environment located in front of the motor vehicle 5. figure 2 illustrates the primary field of view FOV1 (dashed lines) of the primary camera 31 and the primary ground marking M1 and the secondary ground marking M2 seen in the primary field of view FOV1. Note that in a non-limiting embodiment, this step is performed continuously. Since the primary camera 31 is a camera that operates in the visible spectrum, the primary images I1 show the colors C1, C2 of the two primary ground markings M1 and M2. Thus, as illustrated in the figure 2 The primary ground marking M1 and the secondary ground marking M2 are represented with two different colors respectively, a dark one and a light one, in the primary field of view FOV1. The field of view of a camera is otherwise called in Anglo-Saxon language "Field Of View".

[0017] In a second step E2, illustrated F2(32, I2) on the figure 1a said at least one secondary camera 32 acquires secondary images I2 of the external environment on at least one side of said motor vehicle 5. The secondary images I2 thus include images of said primary road marking M1 and said secondary road marking M2 located on one side of said motor vehicle 5. As illustrated in the non-limiting example of the figure 2 The side in question is the left side of the motor vehicle. 5. figure 2 This illustrates the secondary field of view FOV2 (dashed lines) of the secondary camera 32 and the primary ground marking M1 and the secondary ground marking M2 seen in the secondary field of view FOV2. It should be noted that in a non-limiting embodiment, this step is performed continuously. It is thus carried out in parallel with the first step E1. Since the secondary camera 32 is a camera that operates in the infrared or near-infrared range, the secondary images I2 do not show the colors C1, C2 of the two primary ground markings M1 and secondary ground markings M2.

[0018] In a third step E3, illustrated F3(31, I1, C1(M1)) on the figure 1a From the aforementioned primary images I1, the primary camera 31 determines the primary color C1 (represented in dark gray on the figure 2 ) of the primary road marking M1. As the primary camera 31 operates in the visible spectrum, it can differentiate colors from one another. In the non-limiting example shown, it determines that the primary color C1 of the primary road marking M1 is white.

[0019] In a fourth step E4, illustrated F4(31, I1, C2(M2)) on the figure 1a From the aforementioned primary images I1, the primary camera 31 determines the secondary color C2 (represented in light gray on the figure 2 ) of the secondary road marking M2. In the illustrated, non-limiting example, it determines that the secondary color C2 of the secondary road marking M2 is yellow (illustrated light gray on the figure 2 ).

[0020] In a fifth step E5, illustrated F5(31, 33, M1(P1, C1), M2(P2, C2)) on the figure 1a The primary camera 31 transmits to the electronic control unit 33 a primary position vector P1 of the primary road marking M1 with its associated primary color C1, and a secondary position vector P2 of the secondary marking M2 with its associated secondary color C2, the primary position vector P1 and the secondary position vector P2 being obtained from said primary images I1. By primary position vector P1 and secondary position vector P2, we mean the position relative to the motor vehicle 5, in particular relative to a line 51 tangent to the side 50 of the motor vehicle 5.

[0021] In a first, non-limiting embodiment illustrated on the figures 4a And 4b The primary position vector P1(p01->p1) is deduced from an angle β1 between the longitudinal axis Ax and a primary point p1 of a primary image I1 located at the level of said primary ground marking M1. Thus: LP 1 = d 1 sinβ 1 − L 1

[0022] With LP1 its length, p01 its origin point which is on the line 51 tangent to the flank 50, and d1 the distance between a midpoint p0 at the bottom of the primary image I1 and the primary point p1.

[0023] Similarly, in a first, non-limiting embodiment illustrated on the figures 4a And 4b The secondary position vector P2(p02->p2) is deduced from the same angle β1 between the longitudinal axis Ax and a secondary point p2 of a primary image I1 located at the level of said secondary ground marking M2. Thus: LP 2 = d 2 sinβ 1 − L 1

[0024] With LP2 its length, and p02 its origin point which is on a line 51 tangent to the flank 50, and d2 the distance between the midpoint p0 at the bottom of the primary image I1 and the secondary point p2.

[0025] In a second, non-limiting embodiment illustrated on the figure 5a And 5bThe primary position vector P1(p03->p1) is deduced from an angle θ1 between the longitudinal axis Ax and a primary point p1 of a primary image I1 located at the level of said primary ground marking M1. Thus: LP 1 = d 1 sinθ 1 − L 1

[0026] With LP1 its length, and p03 its origin point which is on the line 51 tangent to the flank 50, and d1 the distance between a midpoint p0 at the bottom of the primary image I1 and the primary point p1. The midpoint p0 represents the location of the primary camera 31.

[0027] Similarly, in a second, non-limiting embodiment illustrated in the figures 5a And 5b The secondary position vector P2(p03->p2) is deduced from an angle θ2 different from θ1 between the longitudinal axis Ax and a secondary point p2 of a primary image I1 located at the level of said secondary ground marking M2. Thus, we have: LP 2 = d 2 sinθ 2 − L 1

[0028] With LP2 its length, and p03 its origin point which is on line 51 tangent to flank 50, and d2 the distance between the midpoint p0 at the bottom of the primary image I1 and the secondary point p2.

[0029] The midpoint p0 represents the location of the primary camera 31. In this case, the primary point p1 and the secondary point p2 are aligned along a line perpendicular to the longitudinal axis Ax.

[0030] It should be noted that to carry out the above calculations in the first embodiment and in the second embodiment, we started from the assumption that the motor vehicle 5 travels in parallel with the lines of the road markings M1, M2, which are also parallel.

[0031] In a sixth step E6, illustrated F6(32, 33, M1(P1), M2(P2)) on the figure 1a The secondary camera 32 transmits to the electronic control unit 33 the primary position vector P1 of the primary road marking M1 and the secondary position vector P2 of the secondary road marking M2, the primary position vector P1 and the secondary position vector P2 being obtained from said secondary images I2. By primary position vector P1 and secondary position vector P2, we mean the position relative to the motor vehicle 5, in particular relative to a line 51 tangent to the side 50 of the motor vehicle 5. Thus, the secondary camera 32 will also transmit a primary position vector P1 and a secondary position vector P2, but seen from its point of view.Thus, the electronic control unit 33 will have received two primary position vectors P1 (one from the primary camera 31 and the other from the secondary camera 32), and two secondary position vectors P2 (one from the primary camera 31 and the other from the secondary camera 32). The primary position vector P1 from the primary camera 31 is also called the first primary position vector P1, and the primary position vector P1 from the secondary camera 32 is also called the second primary position vector P1. Similarly, the secondary position vector P2 from the primary camera 31 is also called the first secondary position vector P2, and the secondary position vector P2 from the secondary camera 32 is also called the second secondary position vector P2.

[0032] In the same way as for step five E5, the two non-limiting embodiments illustrated on the figures 5a And 5b are used to determine the primary position vector P1 and the secondary position vector P2, by replacing the primary image I1 with a secondary image I2, and the midpoint p0 of the primary camera 31 with the midpoint (not shown) of the secondary camera 32.

[0033] It should be noted that the primary camera 31 transferred the primary images I1 to the electronic control unit 33, and the secondary camera 32 transferred the secondary images I2 to the electronic control unit 33 via a suitable communication link, such as, but not limited to, a CAN or Ethernet link. It should also be noted that the primary images I1 and the secondary images I2 are refreshed as the motor vehicle 5 moves along the road R1.

[0034] In a seventh step E7, illustrated F7(33, P3, M1, M2) on the figure 1a The electronic control unit 33 determines the relative position vector P3(pA->pB) of the secondary road marking M2 with respect to the primary road marking M1 in the secondary field of view FOV2 from said primary position vectors P1 and said secondary position vectors P2, namely from the first primary position vector P1 and the second primary position vector P1, and from the first secondary position vector P2 and the second secondary position vector P2. Since it has received the primary position vectors P1 and the secondary position vectors P2 from the primary camera 31 and the secondary camera 32, the electronic control unit 33 can deduce the relative position vector P3' in the primary field of view FOV1 and consequently the direction of the relative position vector P3 in the secondary field of view FOV2, towards the vehicle 5 or departing.

[0035] In order to determine the relative position vector P3 in the secondary field of view FOV2, the electronic control unit 33 can perform the following calculation.

[0036] As illustrated on the figure 4a In a first, non-limiting embodiment, the relative position vector P3' is determined with a constant angle β1 defined between: a primary point p1 of a primary image I1 located at the level of said primary ground marking M1 and a longitudinal axis Ax of said motor vehicle 5, and a secondary point p2 of a primary image I1 located at the level of said secondary ground marking M2 and said longitudinal axis Ax1 of said vehicle 5.

[0037] The primary point p1 is at a distance d1 from the primary camera 31 and the secondary point p2 at a distance d2 from the primary camera 31. The primary point p1 and the secondary point p2 are aligned along a line L0 which passes through the primary camera 31, which intersects the primary ground marking M1 and the secondary ground marking M2 and which defines the angle β1 with the longitudinal axis Ax.

[0038] Depending on the speed V of the motor vehicle 5, we know at what time the primary point p1 and the secondary point p2, which are in the primary field of view FOV1 of the primary camera 31, will enter the secondary field of view FOV2 of the secondary camera 32. We thus know that the primary point p1 and the secondary point p2 seen by the primary camera 31 correspond respectively to a tertiary point pA and a quaternary point pB. These two points pA and pB are aligned along a transverse axis Ay perpendicular to the longitudinal axis Ax of the motor vehicle 5. The tertiary point pA is at a distance dA from the motor vehicle 5, and the quaternary point pB is at a distance dB from the motor vehicle 5 along the transverse axis Ay. We therefore have the following relationship. d A = d 1 sinβ 1 − L 1 = LP 1

[0039] With LP1 being the length of the position vector P1, and d B = d 2 sinβ 1 − L 1 = LP 2

[0040] With LP2 being the length of the position vector P2.

[0041] With L1, half the width of the motor vehicle 5. Using this relationship, we can verify that the tertiary point pA and the quaternary point pB, which are seen by the secondary camera 32, are indeed located approximately at the distances dA and dB given by the calculation. The distances dA and dB allow us to deduce the relative position vector P3(pA->pB), with its length dB-dA and its origin pA. The direction of the position vector P3 is the same as that of the position vector P3', towards the vehicle 5 or in the direction of departure. Thanks to the distance dA, we know that the point pA belongs to the marking M1. Thanks to the distance dB, we know that the point pB belongs to the marking M2.

[0042] As illustrated on the figure 5a In a second, non-limiting embodiment, the relative position vector P3' is determined with a variable angle θ defined between: a primary point p1 of a primary image I1 at the level of said primary ground marking M1 and the longitudinal axis Ax of said motor vehicle 5, and a secondary point p2 of a primary image I1 at the level of said secondary ground marking M2 and said longitudinal axis Ax of said motor vehicle 5.

[0043] The primary point p1 is at a distance d1 from the primary camera 31 and the secondary point p2 at a distance d2 from the primary camera 31. The primary point p1 and the secondary point p2 are aligned along a line L0 perpendicular to the longitudinal axis Ax and which intersects the primary ground marking M1 and the secondary ground marking M2.

[0044] Depending on the speed V of the motor vehicle 5, we know at what time the primary point p1 and the secondary point p2, which are in the primary field of view FOV1 of the primary camera 31, will enter the secondary field of view FOV2 of the secondary camera 32. We thus know that the primary point p1 and the secondary point p2 seen by the primary camera 31 correspond respectively to a tertiary point pA and a quaternary point pB. These two points pA and pB are aligned along a transverse axis Ay perpendicular to the longitudinal axis Ax of the motor vehicle 5. The tertiary point pA is at a distance dA from the motor vehicle 5, and the quaternary point pB is at a distance dB from the motor vehicle 5 along the transverse axis Ay. We therefore have the following relationship. d A = d 1 sinθ 1 − L 1 = LP 1

[0045] With LP1 being the length of the position vector P1, and d B = d 2 sinθ 2 − L 1 = LP 2

[0046] With LP2 being the length of the position vector P2.

[0047] With L1, half the width of the motor vehicle 5. Using the following relationship, we can verify that the tertiary point pA and the quaternary point pB, which are seen by the secondary camera 32, are indeed located approximately at the distances dA and dB given by calculation. The distances dA and dB allow us to deduce the relative position vector P3, with its length dB-dA and its origin pA. Thanks to the distance dA, we know that point pA belongs to marking M1. Thanks to the distance dB, we know that point pB belongs to marking M2.

[0048] In an eighth step E8, illustrated F8(33, P3, C2) on the figure 1a The electronic control unit 33 performs a correlation between the secondary color C2 and the relative position vector P3 of said secondary ground marking M2 (relative to the primary ground marking M1) in the secondary field of view FOV2 (using the calculated distances dA, dB). Using the data transmitted by the primary camera 31, namely the primary position vector P1 with its associated primary color C1, the secondary position vector P2 with its associated secondary color C2 as seen by the primary camera 31, and the data transmitted by the secondary camera 32, namely the primary position vector P1 and the secondary position vector P2 as seen by said secondary camera 32, the electronic control unit 33 can associate the secondary color C2 with the relative position vector P3.

[0049] Thus, by determining the secondary color C2 of the secondary ground marking M2 and its relative position vector P3 with respect to the primary ground marking M1, we can differentiate said secondary ground marking M2 from said primary ground marking M1.

[0050] In a second, non-limiting embodiment illustrated on the figure 1b In addition to steps E1 to E8, the differentiation process 1 may also include the following additional steps: the lighting of the primary road marking M1 and the secondary road marking M2 at the front or rear of the vehicle 5 (step E2' illustrated F2'(M1, M2) on the figure 1b ), and / or the lighting of the primary road marking M1 and the secondary road marking M2 on at least one side of the vehicle 5 (step E2" illustrated F2"(M1, M2) on the figure 1b ).

[0051] The lighting is provided by a light module (not shown). This lighting is particularly useful at night. Note that these steps are carried out simultaneously with all steps E1 to E8.

[0052] The differentiation process 1 is thus implemented by the differentiation device 3 illustrated on the figure 3 .

[0053] As illustrated on the figure 3 , the differentiation device 3 comprises the elements the primary camera 31, said at least one secondary camera 32 and the electronic control unit 33.

[0054] The primary camera 31 is configured as follows: acquire primary images I1 of the external environment of said vehicle 5 at the front or rear of said vehicle 5, said primary images I1 comprising images of said primary road marking M1 and said secondary road marking M2 located at the front or rear of said vehicle 5 (function illustrated f1(31, I1)), determine from said primary images I1 the primary color C1 of said primary road marking M1 (function illustrated f3(31, I1, C1(M1))), determine the secondary color C2 of said secondary road marking M2 (function illustrated f4(31, I1, C2(M2))), transmit to the electronic control unit 33 the primary position vector P1 of the primary marking M1 with its associated primary color C1, and the secondary position vector P2 of the secondary marking M2 with its associated secondary color C2, said primary position vector P1 and said secondary position vector P2 being deduced from said primary images I1 (function illustrated f5(31, 33,M1(P1, C1), M2(P2, C2))). ,

[0055] Said at least one secondary camera 32 is configured to: acquire secondary images I2 of said external environment on at least one side of said vehicle 5, said secondary images I2 comprising images of said primary road marking M1 and of said secondary road marking M2 located on said at least one side of said vehicle 5 (function illustrated f2(32, 12)), transmit to said electronic control unit 33 the primary position vector P1 of the primary road marking M1 and the secondary position vector P2 of the secondary road marking M2, said primary position vector P1 and said secondary position vector P2 being deduced from said secondary images I2 (function illustrated f6(32, 33, M1(P1), M2(P2)).

[0056] The said electronic control unit 33 is configured to: determine the relative position vector P3 of said secondary ground marking M2 with respect to the primary ground marking M1 in the secondary field of view FOV2 of the secondary camera 32 from said primary position vectors P1 and said secondary position vectors P2 (function illustrated f7(33, P3, M1, M2)), perform a correlation between the secondary color C2 and the relative position vector P3 of said secondary ground marking M2 in the secondary field of view FOV2 (function illustrated f8(33, P3, C2)).

[0057] The differentiation method 1 can thus be used by any other method requiring differentiation between the primary road marking M1 and the secondary road marking M2, particularly when using a secondary camera 32 which cannot differentiate between the two road markings. Therefore, it can be used for a positioning method 2 of a vehicle 5 relative to a secondary marking M2 on a road R1 on which the vehicle 5 is traveling. This positioning method 2 is illustrated in the figure 6 It includes steps E1 to E8 of the differentiation process 1 and the following additional steps.

[0058] In a ninth step E9, illustrated F9(33, Pos(P3), 5), the electronic control unit 33 calculates the position Pos of the motor vehicle 5 relative to the secondary road marking M2 as a function of the relative position vector P3 of the secondary road marking M2. This position Pos is thus deduced from the previously calculated distance dB. The position of the motor vehicle 5 relative to the road marking M2 is thus determined.

[0059] Following the calculation of the position Pos, depending on the desired application, a specific function is executed.

[0060] In non-limiting embodiments, the specific function that is performed is: a function to automatically park said motor vehicle 5 in the case of an autonomous vehicle, a function to help said motor vehicle 5 to park in the case of a non-autonomous vehicle in a construction zone, a function to automatically change lanes in the case of an autonomous vehicle, a function to display on a human-machine interface the color of the road marking on the side of the vehicle instead of a black and white display, a function to help change lanes, help stay in a lane in a construction zone etc.

[0061] Of course, the description of the invention is not limited to the embodiments and scope described above. Thus, in a non-limiting embodiment, the positioning method 2 may further include illuminating the primary road marking M1 and the secondary road marking M2 at the front or rear of the vehicle 5, and illuminating the primary road marking M1 and the secondary road marking M2 on at least one side of the vehicle 5. It should be noted that in the figures, the standard road marking is located to the right of the temporary road marking. Of course, this can be reversed. In this case, the secondary marking M2 will be to the right of the primary road marking M1. Thus, in a non-limiting embodiment, the differentiation device 3 may include two secondary cameras 32, each positioned on either side of the motor vehicle 5, to acquire secondary images I2 on each side of the motor vehicle 5.Thus, in another non-limiting embodiment, the primary camera 31 can be positioned at a level other than behind the central rearview mirror. Similarly, in another non-limiting embodiment, the secondary camera 32 can be positioned at a level other than in the side mirror.

[0062] Thus, the described invention offers, in particular, the following advantages: It allows us to differentiate a secondary road marking M2 from a primary road marking M1 thanks in particular to its color and to know the location of the secondary road marking M2 in relation to the primary road marking M1, it allows us to deduce the position Pos of the vehicle 5 in relation to the primary road marking M1 and the secondary road marking M2 and thus know which road marking to follow.

Claims

1. Method of differentiation (1) of a secondary ground marking (M2) of a road (R1) on which a vehicle (5) is located from a primary ground marking (M1) of said road (R1), characterized in that said differentiation method (1) comprises: - acquiring (E1) primary images (11) of the external environment of said vehicle (5) at the front or rear of said vehicle (5) by a primary camera (31), said primary images (11) comprising images of said primary ground marking (M1) and said secondary ground marking (M2) located at the front or rear of said vehicle (5), - acquiring (E2) secondary images (12) of said external environment on at least one side of said vehicle (5) by at least one secondary camera (32), said secondary images (12) comprising images of said primary ground marking (M1) and said secondary ground marking (M2) located on said at least one side of said vehicle (5), - from said primary images (11), determining (E3) by said primary camera (31) the primary color (C1) of said primary ground marking (M1), - from said primary images (11), determining (E4) by said primary camera (31) the secondary color (C2) of said secondary ground marking (M2), - transmitting (E5) by the primary camera (31) to an electronic control unit (33) a primary position vector (P1) of the primary marking (M1) with its associated primary color (C1), and a secondary position vector (P2) of the secondary marking (M2) with its associated secondary color (C2), said primary position vector (P1) and said secondary position vector (P2) being derived from said primary images (11), - transmitting (E6) by the secondary camera (32) to said electronic control unit (33) a primary position vector (P1) of the primary ground marking (M1) and a secondary position vector (P2) of the secondary ground marking (M2), said primary position vector (P1) and said secondary position vector (P2) being derived from said secondary images (12), - determining (E7) by said electronic control unit (33) a relative position vector (P3) of said secondary ground marking (M2) with respect to the primary ground marking (M1) in the secondary field of vision (FOV2) of the secondary camera (32) from said primary position vectors (P1) and said secondary position vectors (P2), - correlating (E8) by said electronic control unit (33) between the secondary color (C2) and said relative position vector (P3) of said secondary ground marking (M2) in the secondary field of vision (FOV2), wherein said relative position vector (P3) is determined with a constant angle (β1) defined between: - a longitudinal axis (Ax) of said vehicle (5), and - a half-line having as origin a midpoint (p0) at the bottom of a primary image (11) and passing through a primary point (p1) of said primary image (11) at the level of said primary ground marking (M1) and through a secondary point (p2) of said primary image (11) at the level of said secondary ground marking (M2), and wherein said relative position vector (P3) is determined with a variable angle (0) defined by two values (01, 02) of which: - one value (01) is defined between a longitudinal axis (Ax) of said vehicle (5) and a half-line having as origin a midpoint (p0) at the bottom of a primary image (11) and passing through a primary point (p1) of said primary image (11) at the level of said primary ground marking (M1), and - the other value (02) is defined between said longitudinal axis (Ax) of said vehicle (5) and a half-line having as origin said midpoint (p0) and passing through a secondary point (p2) of said primary image (11) at the level of said secondary ground marking (M2), said primary point (p1) and said secondary point (p2) being aligned along a line (L0) perpendicular to said longitudinal axis (Ax) of said vehicle (5).

2. Differentiation method (1) according to claim 1, wherein said differentiation method (1) further comprises: - illuminating (E2') said primary ground marking (M1) and said secondary ground marking (M2) at the front or rear of said vehicle (5), and / or - -1 illuminating (E2") said primary ground marking (M1) and said secondary ground marking (M2) on at least one side of said vehicle (5).

3. Differentiation method (1) according to any one of the preceding claims, wherein said electronic control unit (33) is part of the primary camera (31) or is separate from said primary camera (31).

4. Method of positioning (2) a vehicle (5) with respect to a secondary marking (M2) of a road (R1), characterized in that the positioning method (2) is the differentiation method (1) according to claim 1, and further comprises: calculating (E9) the position (Pos) of said vehicle (5) with respect to said secondary ground marking (M2) based on the relative position vector (P3).

5. Differentiation device (3) of a secondary ground marking (M2) of a road (R1) on which a vehicle (5) is located from a primary ground marking (M1) of said road (R1), characterized in that said differentiation device (3) comprises: - a primary camera (31) configured to acquire primary images (11) of the external environment of said vehicle (5) at the front or rear of said vehicle (5), said primary images (11) comprising images of said primary ground marking (M1) and said secondary ground marking (M2) located at the front or rear of said vehicle (5), at least one secondary camera (32) configured to acquire secondary images (12) of said external environment on at least one side of said vehicle (5), said secondary images (12) comprising images of said primary ground marking (M1) and said secondary ground marking (M2) located on said at least one side of said vehicle (5), - said primary camera (31) being further configured to determine from said primary images (11) the primary color (C1) of said primary ground marking (M1) and the secondary color (C2) of said secondary ground marking (M2), and to transmit to an electronic control unit (33) a primary position vector (P1) of the primary marking (M1) with its associated primary color (C1), and a secondary position vector (P2) of the secondary marking (M2) with its associated secondary color (C2), said primary position vector (P1) and said secondary position vector (P2) being derived from said primary images (11), - said secondary camera (32) being further configured to transmit to said electronic control unit (33) a primary position vector (P1) of the primary ground marking (M1) and a secondary position vector (P2) of the secondary ground marking (M2), said primary position vector (P1) and said secondary position vector (P2) being derived from said secondary images (12), and characterized in that said differentiation device (3) further comprises: - said electronic control unit (33) configured to determine a relative position vector (P3) of said secondary ground marking (M2) with respect to the primary ground marking (M1) in the secondary field of vision (FOV2) of the secondary camera (32) from said primary position vectors (P1) and said secondary position vectors (P2), and to perform a correlation between the secondary color (C2) and said relative position vector (P3) of said secondary ground marking (M2) in the secondary field of vision (FOV2), wherein said relative position vector (P3) is determined with a constant angle (f31) defined between: - a longitudinal axis (Ax) of said vehicle (5), and - a half-line having as origin a midpoint (p0) at the bottom of a primary image (11) and passing through a primary point (p1) of said primary image (11) at the level of said primary ground marking (M1) and through a secondary point (p2) of said primary image (11) at the level of said secondary ground marking (M2), and wherein said relative position vector (P3) is determined with a variable angle (0) defined by two values (01, 02) of which: - one value (01) is defined between a longitudinal axis (Ax) of said vehicle (5) and a half-line having as origin a midpoint (p0) at the bottom of a primary image (11) and passing through a primary point (p1) of said primary image (11) at the level of said primary ground marking (M1), and - the other value (02) is defined between said longitudinal axis (Ax) of said vehicle (5) and a half-line having as origin said midpoint (p0) and passing through a secondary point (p2) of said primary image (11) at the level of said secondary ground marking (M2), said primary point (p1) and said secondary point (p2) being aligned along a line (L0) perpendicular to said longitudinal axis (Ax) of said vehicle (5).