Lane recognition for motor vehicles

Abstract

The invention relates to a lighting system 200 of a motor vehicle, comprising: - an image capturing device (205) configured to acquire an image (I) of a road (R) on which the vehicle is travelling, said road (R) comprising a marked lane (110) on the road; - a lighting module (215) configured to project road markings (120) on the road; wherein the lighting system (200) is configured to filter the projected road markings (120) on the road in contrast with the marked lane (110) on the road.

Description

TECHNICAL FIELD

[0001] The present invention relates to a vehicle, in particular to a lighting system and a synchronization method for providing driving assistance to a vehicle. BACKGROUND

[0002] Nowadays, motor vehicles comprise more and more systems assisting the driver in driving. For example, these systems provide the driver with information about the environment, such as obstacles, vehicles in blind spots, and can help the driver to stay in his own lane or to overtake another vehicle. These systems, called Advanced Driver Assistance Systems (ADAS), thus improve safety and therefore allow to reduce the number of road accidents.

[0003] Moreover, motor vehicles are significantly developing towards autonomous vehicles and self-driving vehicles. In autonomous vehicles, the management of control commands can be automatically ensured by control systems, for example for parking operations or low-speed driving. In self-driving vehicles, the management of control commands can be automatically ensured by control systems for all driving tasks.

[0004] To implement functions such as lane keeping, lane centering, overtaking assistance for an assisted driver or an autonomous vehicle or a self-driving vehicle, the ADAS must in particular detect the road lanes and the road boundaries. Therefore, the ADAS is currently equipped with a camera able to capture an image of the road in front of the vehicle and a computing unit able to calculate the position of the marked lanes on this road.

[0005] To transmit the information captured by the camera and calculated by the computing unit to the driver or to the occupants of the autonomous vehicle or self-driving vehicle, the ADAS can comprise a lighting system for displaying or projecting a plurality of pictograms on the road. As Figure 1 illustrated, the lighting module can display or project on the road a line 120, for example a white line, in order to display the size of the vehicle or the trajectory of the vehicle when overtaking another vehicle, or to display a safety distance with other vehicles.

[0006] However, when the camera of the ADAS captures an image of the road while the lighting module is projecting a line, the computing unit cannot distinguish between the marked lanes on the road and the projected line. This inability to distinguish leads to safety problems. The information transmitted to the driver or to the control system of the autonomous vehicle or self-driving vehicle is not accurate. The projected line can not be projected in the right place and the driver can not be able to identify whether there is enough space to pass or overtake the other vehicle and the control system can not be able to center the vehicle on the road and can make the vehicle wobble. SUMMARY

[0007] It is an object of the present invention to provide a lighting system that improves safety by improving lane detection to avoid any confusion between marked lanes on the road and road markings projected by the lighting module of the vehicle.

[0008] It is another object of the present invention to provide different methods for synchronizing the operation of the lighting module of a vehicle with the operation of an image capturing device of the vehicle to provide driving assistance to motor vehicles, in particular in low lighting conditions.

[0009] According to an embodiment of the present invention, a lighting system of a motor vehicle is provided. The lighting system comprises: an image capturing device configured to capture images of a road on which the vehicle is driving, the road comprising marked lanes on the road; a lighting module configured to project road markings on the road; a control unit, wherein the lighting system is configured to filter the projected road markings on the road in contrast to the marked lanes on the road.

[0010] In one embodiment, the lighting module is configured to project road markings on the road using pulsed light beams.

[0011] In one embodiment, the image capturing device comprises an image processing unit configured to compute the position of the marked lanes on the road, and the control unit is configured to compute the position of the road markings to be projected on the road based on the position of the marked lanes on the road.

[0012] In a first non-limiting embodiment, the control unit is further configured to send the position of the road markings to be projected on the road to the image processing unit, and the image processing unit integrates the position of the road markings to be projected on the road in order to distinguish between the marked lanes on the road and the projected road markings on the road.

[0013] In a second non-limiting embodiment, the lighting module is configured to project road markings on the road using pulsed light beams, and the image processing unit is further configured to: identify in the image the projected road markings on the road corresponding to the pulsed light beams in order to distinguish between the marked lanes on the road and the projected road markings on the road.

[0014] In one embodiment, the image processing unit is configured to:

[0015] - distinguish between pulsed light areas corresponding to the projected road markings on the road, and non-pulsed areas corresponding to the marked lanes on the road,

[0016] - excluding the pulsed light area,

[0017] - remembering the non-pulsed area,

[0018] - transmitting information about the non-pulsed area to the control unit.

[0019] In one embodiment, the image capturing device has an acquisition frequency and the illumination module has a pulsing frequency, the pulsing frequency being lower than the acquisition frequency.

[0020] In one embodiment, the pulsing frequency is a divisor of the acquisition frequency.

[0021] In a third non-limiting embodiment, the control unit is configured to, in a first mode, deactivate the illumination module and simultaneously activate the image capturing device, and in a second mode, activate the illumination module and simultaneously deactivate the image capturing device.

[0022] In one embodiment, the image capturing device comprises an image processing unit configured to calculate the position of the marked lane on the road, and the control unit is configured to calculate the position of the road marking to be projected on the road based on the position of the marked lane on the road. Furthermore, the illumination module is configured to project a segmented illumination beam.

[0023] In one embodiment, the image capturing device operates in a pulsed manner in which the acquisition of images is activated during a predetermined time interval T1 and deactivated during a predetermined time interval T2, the time interval T1 being followed in sequence by the time interval T2. The image capturing device is configured to operate in the first mode for the predetermined time interval T1 and in the second mode for the predetermined time interval T2. The image capturing device is configured to activate the first mode at the rising edge of the pulse and the second mode at the falling edge of the pulse, the pulse duration corresponding to the predetermined time interval T1.

[0024] During the first mode, the image capturing device is configured to send a synchronization signal to the control unit at the rising edge of the pulse, and the control unit is configured to send a deactivation signal to the illumination module upon reception of the synchronization signal, and the image capturing device is configured to acquire images during the time interval T1. During the second mode, the image capturing device is configured to send a synchronization signal to the control unit at the falling edge of the pulse, and the control unit is configured to send an activation signal to the illumination module upon reception of the synchronization signal, and the illumination module is configured to project road markings on the road during the predetermined time interval T2.

[0025] In one embodiment, said time period T1 and said time period T2 are in the range of about 14 ms to 66 ms.

[0026] According to another embodiment of the present application, there is also provided a method comprising the steps of:

[0027] - acquiring, by an image capturing device, an image of a road on which a vehicle is travelling;

[0028] - projecting, by an illumination module, road markings on said road; and

[0029] - filtering the road markings projected on said road in contrast to the marked lane on said road.

[0030] In a first non-limiting embodiment, said method further comprises:

[0031] - calculating, by an image processing unit within said image capturing device, a position of the marked lane on said road;

[0032] - calculating, by a control unit, a position of road markings to be projected on said road based on the position of the marked lane on said road.

[0033] In one embodiment, said method further comprises:

[0034] - sending, from said control unit, said position of road markings to be projected on said road to said image processing unit; and

[0035] - integrating, by said image processing unit, said position of road markings to be projected on said road in order to distinguish between the marked lane on said road and the projected road markings on said road.

[0036] In a second non-limiting embodiment, said method further comprises:

[0037] - projecting, by said illumination module, road markings on said road using a pulsed light beam;

[0038] - identifying, by an image processing unit within said image capturing device, in said image, the projected road markings on said road corresponding to said pulsed light beam in order to distinguish between the marked lane on said road and the projected road markings on said road.

[0039] According to another embodiment of the application, there is provided a method for synchronizing operation of a lighting module of a motor vehicle with an image capturing device, the method comprising: capturing, by the image capturing device, an image of a road on which the vehicle is travelling; and projecting, by the lighting module, road markings on the road. The method further comprises: in a first mode, deactivating, by a control unit, the lighting module and simultaneously activating the image capturing device; and in a second mode, activating, by the control unit, the lighting module and simultaneously deactivating the image capturing device.

[0040] The method further comprises: calculating a position of a lane marked on the road; and calculating a position of road markings to be projected on the road based on the position of the lane marked on the road.

[0041] In one embodiment, the method comprises: operating the image capturing device in a pulsed manner in which the capturing of an image is activated during a predetermined time interval T1 and the capturing of the image is deactivated during a predetermined time interval T2, the time interval T1 being followed in sequence by the time interval T2. The image capturing device is operated in the first mode for the predetermined time interval T1; and the image capturing device is operated in the second mode for the predetermined time interval T2.

[0042] Further, in one embodiment, the operation of the image capturing device in the first mode comprises the steps of: sending, by the image capturing device, a synchronization signal to the control unit on a rising edge of the pulse; sending, by the control unit, a deactivation signal to the lighting module upon receipt of the synchronization signal; and capturing, by the image capturing device, the image during the predetermined time interval T1.

[0043] In one embodiment, the operation of the image capturing device in the second mode comprises the steps of: sending, by the image capturing device, a synchronization signal to the control unit on a falling edge of the pulse; sending, by the control unit, an activation signal to the lighting module upon receipt of the synchronization signal; and projecting, by the lighting module, the road markings on the road during the predetermined time interval T2.

[0044] It should be noted that all the described embodiments are non-limiting.

[0045] Accordingly, the present application provides a lighting system and different methods, wherein the synchronization method is used to accurately distinguish between a marked lane on the road and a road marking projected by the lighting module by synchronizing the operation of the lighting module and the operation of the image capturing device. The accurate distinction between the marked lane and the projected road marking enables the driver of the vehicle or the ADAS system to drive the vehicle on the correct path in low lighting conditions, thus preventing accidents from occurring. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to accomplish the described and in order to provide a better understanding of the present application, a set of drawings is provided. Said drawings form an integral part of the description and illustrate embodiments of the present application, which should not be interpreted as limiting the scope of the present application, but merely as an example of how the present application can be carried out. The drawings comprise the following features.

[0047] Figure 1 A schematic view of a motor vehicle with a marked lane on the road and a road marking projected by a lighting module of the motor vehicle is shown according to an embodiment of the present application.

[0048] Figure 2 is a schematic view of a block diagram of a lighting system of a motor vehicle according to an embodiment of the present application, said lighting system comprising an image capturing device, a lighting module and a control unit.

[0049] Figure 3a The functions of the image capturing device, the functions of the lighting module and the functions of the control unit according to a first non-limiting embodiment are shown,

[0050] Figure 3b The functions of the image capturing device, the functions of the lighting module and the functions of the control unit according to a second non-limiting embodiment are shown,

[0051] Figure 3c The functions of the image capturing device, the functions of the lighting module and the functions of the control unit according to a third non-limiting embodiment are shown,

[0052] Figure 4 is a block diagram of a lighting system according to an embodiment of the present application, Figure 3a is a flowchart of a method performed by the lighting system of

[0053] Figure 5 is a block diagram of a lighting system according to an embodiment of the present application, Figure 3b is a flowchart of a method performed by the lighting system of

[0054] Figures 6a to 6c show the progression in time of the signals according to an embodiment of the present application.

[0055] Figure 7 is a block diagram of a lighting system according to an embodiment of the present application,Figure 3c a flowchart of a method for synchronizing operations of an image capturing device and a lighting module coupled to a motor vehicle performed by a lighting system. DETAILED DESCRIPTION

[0056] The following detailed description describes various features and functions of the disclosed systems and methods with reference to the

[0057] Autonomous vehicles operating on a road can rely on identifying lane boundaries or lane markings on the road for navigation. A computing device configured to control the vehicle, i.e., an advanced driver assistance system (ADAS), can be configured to access road information that can indicate lane boundaries on the road. Typically, an image capturing device coupled to the vehicle captures an image of the road on which the vehicle is traveling, and the image is further processed to identify lane boundaries on the road. However, in certain situations, the captured road information can contain inaccuracies in the estimation of the lane boundaries. For example, at night, the headlamps of the vehicle can project road markings, e.g., lanes on the road, and the road information captured by the image capturing device can include information related to the projected road markings as well as lane boundaries or lane markings on the road. This can cause confusion to the computing device identifying lane boundaries or lane markings on the road for navigation.

[0058] The present subject matter relates to a lighting system and a synchronization method for distinguishing between a lane marked on a road and road markings projected by a lighting module of a motor vehicle.

[0059] Figure 2 is a schematic diagram of a block diagram of a lighting system of a motor vehicle according to an embodiment of the present invention. The motor vehicle is, for example, a passenger car.

[0060] As Figure 2 shown, the lighting system 200 comprises an image capturing device 205 configured to acquire an image of a road R (shown in Figure 1 ) on which the vehicle is traveling (function fl shown in Figures 3a to 3c ), the road R comprising a lane 110 (shown in Figure 1 ) marked on the road; a lighting module 215 configured to project road markings 120 (shown in Figure 1 ) on the road (function f2 shown in Figures 3a to 3c ); and a control unit 220.

[0061] In an aspect, the image capturing device 205 can be any camera (e.g., still camera, video camera) configured to capture images of the driving road of the vehicle. In an aspect, the image capturing device 205 is coupled to the vehicle and can be positioned behind the rearview mirror of the vehicle, or positioned at the front bumper of the vehicle.

[0062] Further, in one embodiment, the image capturing device 205 comprises an image processing unit 225 for processing the captured images to calculate the position pi of the marked lane 110 on the illustrated road (function f3 illustrated in Figure 1 Figures 3a to 3c The image processing unit 225 calculates the coordinates of the marked lane 110 on the road. In one embodiment, the image processing unit 225 is electrically coupled to the image sensor 230.

[0063] The shutter 235 is used to cover the image sensor 230 from the environmental area. The shutter 235 can move back and forth between an open position and a closed position. The image sensor 230 is electrically coupled to the image processing unit 225.

[0064] In one embodiment, the image capturing device 205 can be electrically coupled to the illumination module 215. The illumination module 215 comprises at least a light source 240, and the illumination module 215 is configured to project a segmented illumination beam (function f4 illustrated in Figures 3a to 3c The segmented illumination beam is a beam having a plurality of segments that are selectively activatable to project road markings such as lines. In a first example, the illumination module 215 comprises a matrix of micro-mirrors. The micro-mirrors can switch between two angles. In a first angle position, light received from the light source 240 of the illumination module 215 is reflected along a first direction and contributes to form the illumination beam. In a second angle position, the received light is reflected along a second direction and does not contribute to form the illumination beam.

[0065] In a second example, the light source 240 of the illumination module 215 is a laser light source such as a laser diode, and the illumination module 215 comprises a light conversion device onto which light emitted from the laser light source is directed. The laser light source scans the light conversion device to draw an image that is projected to form the illumination beam.

[0066] In a third example, the illumination module 215 comprises a plurality of light sources. Each light source is associated with an optical element to form a light segment. Each light segment is projected by a projection element to form the illumination beam.

[0067] In a fourth non-limiting example, the light source 240 of the illumination module 215 is any type of LED.

[0068] ​In a fifth non-limiting example, the light source 240 of the lighting module 215 is an infrared light source.

[0069] With reference to Figure 3a , Figure 3b and Figure 3c , the lighting system 200 is further described according to 3 non-limiting embodiments.

[0070] In a first non-limiting embodiment illustrated in Figure 3a , the control unit 220 is configured to compute a position p2 of the road marking 120 to be projected on the road based on a position pi of the marked lane 110 on the road (function f5 illustrated in Figure 3a ). In particular, the control unit 220 computes the coordinates of the road marking 120.

[0071] The control unit 220 is further configured to send said position p2 of the road marking 120 to be projected on the road to said image processing unit 225 (function f6 illustrated in Figure 3a ).

[0072] Upon reception of said position p2, the image processing unit 225 integrates said position p2 of the road marking 120 to be projected on the road in order to distinguish the marked lane 110 on the road from the projected road marking 120 on the road (function f7 illustrated in Figure 3a ). Because the position pi of the marked lane 110 on the road is known to the image processing unit 225, and since the position pi and the position p2 are different, in particular because of the different coordinates, said image processing unit 225 can distinguish the projected road marking 120 from the lane marking 110 on the road. Thus, when the image capture device 205 captures the image I of the road R, it captures the marked lane 110 on the road and the projected road marking 120 on the road, and then, thanks to the position pi and the position p2, it filters out said projected road marking 120 on the road so that said projected road marking 120 on the road does not need to be taken into account for the management of the control commands of the ADAS. Thus, this avoids confusion between said marked lane 110 on the road and said projected road marking 120.

[0073] In a second non-limiting embodiment illustrated in Figure 3b , the lighting module 215 is configured to project the road marking 120 on the road using a pulsed light beam Wi (function f2 illustrated in Figure 3b , and the image processing unit 225 is further configured to identify in said image I the projected road marking 120 on the road corresponding to the pulsed light beam Wi (function f3 illustrated in Figure 3b- distinguishing the marked lane 110 on the road from the projected road marking 120 on the road (function f8) illustrated in Fig. 8, so as to distinguish the marked lane 110 on the road from the projected road marking 120 on the road.

[0074] The pulsed light beam W1 is generated by the illumination module 215, in particular by the light source 240 which emits the light beam discontinuously. The pulsed light beam W1 is formed by a succession of light pulses, most typically by a frequency-modulated electrical signal which supplies the light source 240 which emits the light beam.

[0075] Within a short period of time, no light beam is emitted between each emitted light pulse, the repetition of which is periodic. The pulsed nature of the light beam is therefore necessarily transformed by the very short interruption of the light beam under consideration. Advantageously, this interruption is invisible to the human eye, this interruption either by a selected pulse frequency (sometimes also referred to as frequency modulation) or by the use of invisible rays (for example, infrared rays), this interruption resulting in a flicker which is invisible to the human eye.

[0076] The image processing unit 225 is therefore configured to:

[0077] - distinguish the pulsed light regions corresponding to the projected road markings 120 on the road, the non-pulsed regions corresponding to the marked lanes 110 on the road (function f10) illustrated in Fig. 10, Figure 3b

[0078] - exclude the pulsed light regions (function f11) illustrated in Fig. 11, Figure 3b

[0079] - remember the non-pulsed regions (function f12) illustrated in Fig. 12, Figure 3b

[0080] - transmit information relating to the non-pulsed regions to the control unit 220 (function f13) illustrated in Fig. 13. These information will be used for the management of the control commands of the ADAS. Figure 3b

[0081] The image processing unit 225 therefore filters the projected road markings 120 on the road due to the pulsed light beam W1, so that these projected road markings 120 on the road are not taken into account for the management of the control commands of the ADAS. It thus avoids confusion between the marked lanes 110 on the road and the projected road markings 120.

[0082] ​​​​It should be noted that the image capture camera 205 is set so that the image processing unit 225 can recognize the projected road marking 120 emitted in a pulsed manner. Indeed, on the images I of the road captured by the image capture device 205, the reflection of the projected road marking 120 will be reflected by a regular flicker. On the contrary, the marked lane 110 does not cause a flicker because it is present on all the images captured by the image capture device 205.

[0083] In one non-limiting embodiment, the image capture device 205 has a capture frequency fql of the images I and the illumination module 215 has a pulsed frequency fq2 (of the projected road marking 120) which is lower than the capture frequency fql. Thus, for example, in two successive images I captured by the image capture device 205, the marked lane 110 on the road will always appear, whereas the projected road marking 120 will only appear in one image I and not in the following image I. The image processing unit 225 can thus automatically distinguish between the marked lane 110 and the projected road marking 120. This avoids confusion between the two different markings.

[0084] In one non-limiting embodiment, the illumination module 215 emits at a frequency belonging to the visible spectrum so that the projected road marking 120 is visible to the driver; the illumination module 215 is powered by a voltage having a very high duty cycle, for example a duty cycle of about ninety percent, that is to say that the pulsed light beam Wl is interrupted for ten percent of the total emission time, in one non-limiting embodiment, this can be achieved in particular by LEDs. In one non-limiting embodiment, the pulsed frequency fq2 is a divisor of the capture frequency fql. In one non-limiting example, the pulsed frequency fq2 is 15 Hz and the capture frequency fql is 30 Hz, or 30 images per second. A divisor of a number is a value obtained by dividing the considered number by a natural number. A pulsed frequency of 15 Hz means that the illumination module 225 producing the pulsed light beam Wl emits 15 pulses per second. More generally, the pulsed frequency fq2 of the illumination module 225 is chosen to be lower than the capture frequency fql of the image capture device 205. Thus, it is certain that at a given moment the flicker (also called the flickering) is obtained on all the captured images I. Choosing a divisor for the pulsed frequency fq2 makes it possible to observe this flickering very regularly and on a limited number of successive images I. In the example given here, the flickering is observed once every two images.

[0085] It should be noted that the pulse frequency fq2 used is known to the image processing unit 225. This known (pulse frequency) can overcome the risk of misinterpreting the signal from an external modulated light source, for example a modulated light source of another equivalent vehicle outside the vehicle under consideration.

[0086] In a third non-limiting embodiment illustrated in Figure 3c , the control unit 220 is configured to, in a first mode, deactivate the lighting module 215 (function f20 illustrated in Figure 3c ) and simultaneously activate the image capture device 205 (function f21 illustrated in Figure 3c ), and the control unit 220 is also configured to, in a second mode, activate the lighting module 215 (function f22 illustrated in Figure 3c ) and simultaneously deactivate the image capture device 205 (function f23 illustrated in Figure 3c ).

[0087] In one non-limiting embodiment, the control unit 220 is also configured to calculate the position p2 of the road marking 120 to be projected on the road based on the position of the marked lane 110 on the road (function f5 illustrated in Figure 3c ).

[0088] The control unit 220 is also configured to send the position p2 of the road marking 120 to be projected on the road to the image processing unit 225 (function f6 illustrated in Figure 3c ).

[0089] As previously mentioned, the image capture device 205 is configured to operate in a first mode and in a second mode. In one embodiment, the image capture device 205 is configured to operate in the first mode for a predetermined time interval T1 and in the second mode for a predetermined time interval T2. The shutter 235 of the image capture device 205 moves back and forth between an open position and a closed position in the first mode and in the second mode in order to activate and deactivate the operation of the image capture device 205. In order to synchronize the operation of the image capture device 205 and the lighting module 215, the movement of the shutter 235 occurs in synchronization with the switching of the lighting module 235 during the vehicle travel time T.

[0090] The image capture device 205 operates in a pulsed manner in which the acquisition of images is activated during a predetermined time interval T1 and deactivated during a predetermined time interval T2, said time interval T1 being followed by said time interval T2, in a sequential manner. In Figure 3aThe periodic switching of the image capturing device 205 during the vehicle travel time T is illustrated in the middle. The operation of the image capturing device 205 switches between a state "0" and a state "1". The state "0" is an inactive state, in which the image capturing device 205 is deactivated, i.e. turned off. In contrast, in the state "1" and thus in the active state, the image capturing device 205 is activated, i.e. turned on.

[0091] In one embodiment, the control unit 220 is configured to synchronize the operation of the image capturing device 205 with the operation of the illumination module 215. For example, the control unit 220 is a driver of the illumination module 215. In case the illumination module 215 is located in a headlamp, the control unit 220 can be a driver of the headlamp. The control unit 220 is configured to send an activation signal or to send a deactivation signal to the illumination module 215 upon receiving a synchronization signal from the image capturing device 205.

[0092] In the first mode, the image capturing device 205 is configured to send a synchronization signal to the control unit 220 at the rising edge of the pulse. Furthermore, the control unit 220 is configured to send a deactivation signal to the illumination module 205 upon receiving the synchronization signal, and the image capturing device 205 is configured to acquire an image during a predetermined time interval T1. The time interval T1 corresponds to the integration time, which is the duration of the image capturing. The captured image is processed by the image processing unit 225 to calculate the position of the lane 210 marked on the road. In particular, the image processing unit 225 calculates the coordinates of the lane 110 marked on the road. The calculation of the coordinates of the lane marked on the road by processing the image is well known to the person skilled in the art and thus the details of the calculation are not provided herein. Furthermore, the coordinates of the lane 110 marked on the road are sent by the image processing unit 225 to the control unit 220.

[0093] In the second mode, the image capturing device 205 is configured to send a synchronization signal to the control unit 220 at the falling edge of the pulse. The control unit 220 is configured to send an activation signal to the illumination module 205 upon receiving the synchronization signal, and the illumination module 205 is configured to project the road marking on the road during a predetermined time interval T2. The illumination module 205 projects the marking on the road based on the calculated lane coordinates. The time interval T2 corresponds to the operation time of the illumination module 205. The size of the time interval T2 is set such that the driver of the vehicle can always see the lane 110 marked on the road without any flickering.

[0094] According to an embodiment of the present application, the values of the preset time intervals T1 and T2 are in the range of about 14 ms to about 66 ms. That is, the image capturing device 205 and the illumination module 215 switch between the active state and the inactive state with a frequency in the range of about 15 Hz to about 70 Hz. In another embodiment, the values of the time intervals T1 and T2 are equal to 50 ms, i.e. the image capturing device 205 and the illumination module 215 switch between the active state and the inactive state with a frequency of 50 Hz. The preset time intervals T1 and T2 are chosen in the above-mentioned range so that the flickering is not visible to the human eye and thus so that the driver and the passengers can see a continuous light.

[0095] During the vehicle driving time T, the image capturing device 210 operates synchronously with the illumination module 215 so that during the operation of the image capturing device 205, the illumination module 210 does not project the road marking 120 on the road and thus the marked lane 110 on the road can be identified without any confusion. Thus, in an autonomous vehicle, the ADAS system piloting the vehicle can easily identify the marked lane 120 on the road for navigation. Similarly, by projecting the road marking 120 based on the identification of the marked lane 110 on the road, the driver of the autonomous vehicle can easily identify whether there is enough space to pass or overtake other vehicles and thus accidents can be prevented.

[0096] Now referring to Figures 6a to 6c, the synchronous operation of the image capturing device 205 and the illumination module 215 according to an embodiment of the present inventive subject matter is explained in more detail. In Figure 6a, the operation of the image capturing device 205 is shown and thus the temporal progress of the state of the image capturing device 205 is shown. In particular, in Figure 6a, the temporal progress of the movement of the shutter of the image capturing device is shown, which moves between an open position and a closed position. In Figure 6b, the temporal progress of the pulses is shown. In Figure 6c, the temporal progress of the operation of the illumination module 215 is shown.

[0097] As already explained with reference to Figure 2 the image capturing device 205 operates in the first mode and the second mode during the vehicle driving time T so that during the operation of the image capturing device 205, the lane marking 120 is not projected on the road by the illumination module 210.

[0098] In one embodiment, at the beginning of the synchronization process, the light source 240 in the lighting module 215 can be switched off for a certain time period. As is evident from Fig. 6a and Fig. 6c, at the beginning of the synchronization process, the light source is switched off for a certain time period during the capturing and processing of the first image. The predetermined time interval T1 corresponds to the integration time, i.e. the time required to capture the image, and the time interval T2 corresponds to the processing time of the image captured during T1. The processing of the image comprises calculating the coordinates of the marked lane on the road and sending the calculated coordinates of the marked lane on the road to the control unit 220.

[0099] After the duration for capturing and processing the first image has elapsed, the image capturing device 205 sends the calculated coordinates of the marked lane on the road from the first image to the control unit 220.

[0100] Subsequently, the capturing of the second image is started during the time interval T1 and the control unit 220 calculates the coordinates of the road marking to be projected in the time interval T1 based on the coordinates of the marked lane in the first image. In one embodiment, at the rising edge of the pulse, the image capturing device 205 sends a synchronization signal to the control unit 220 and the image capturing device 205 captures the second image during the time interval T1. The control unit 220 in turn sends a deactivation signal to the lighting module during the rising edge of the pulse to deactivate the lighting module. Further, at the falling edge of the pulse, the image capturing device 205 sends a synchronization signal to the control unit 220 and the control unit 220 sends an activation signal to the lighting module 205.

[0101] During the processing time of the second image, the lighting module 205 is activated to project the road marking on the road based on the coordinates of the lane calculated from the first image. During the capturing of the second image, i.e. during the integration time, the lighting module 215 is deactivated so as not to project the road marking at the same time as the image capturing. Similarly, as is evident from Fig. 6a and Fig. 6c, during the processing of the third image, the lighting module 215 is activated based on the coordinates of the projected lane calculated from the second image; and during the integration time of the third image, the lighting module 215 is deactivated.

[0102] Thus, during the vehicle travel time T, the lighting module 215 operates in synchronization with the image capturing device 205 such that the deactivation of the lighting module 215 occurs simultaneously with the activation of the image capturing device 205 and vice versa, as is evident from Fig. 6a and Fig. 6c.

[0103] The lighting system 200 is configured to perform a method 1, as shown in Figure 4 and 5 The method 1 comprises the following steps:

[0104] - in F210 (205, I, R, 110) illustrated in step S210, an image I of a road R on which the vehicle is travelling is acquired by means of an image capturing device 205, said road R comprising a lane 110 marked on the road;

[0105] - in F220 (215, 120) illustrated in step S220, road markings are projected on a road 120 by means of an illumination module 215; and

[0106] - in F230 (110, 120) illustrated in step S230, the road markings projected on the road 120 are filtered in contrast with the lane 110 marked on the road.

[0107] According to Figure 4 the first non-limiting embodiment illustrated in figure 1, the method 1 further comprises:

[0108] - in F240 (225, pi) illustrated in step S240, a position pi of the lane 110 marked on the road is calculated by means of an image processing unit 225 within said image capturing device 205;

[0109] - in F250 (220, p2) illustrated in step S250, a position p2 of the road markings 120 to be projected on the road is calculated by means of a control unit 220 on the basis of the position of the lane 110 marked on the road;

[0110] - in F260 (220, 225, p2) illustrated in step S260, said position p2 of the road markings to be projected on the road 120 is sent from said control unit 220 to said image processing unit 225; and

[0111] - in F270 (225, p2, 110, 120) illustrated in step S270, said position p2 of the road markings 120 to be projected on the road is integrated by means of said image processing unit 225 in order to distinguish the lane 110 marked on the road from the road markings 120 projected on the road.

[0112] According to Figure 5 the second non-limiting embodiment illustrated in figure 2, the method 1 further comprises:

[0113] - in F280 (215, 120, Wi) illustrated in step S280, the road markings 120 are projected on the road by means of said illumination module 215 using a pulsed light beam Wi;

[0114] - in a step S290, illustrated as F290 (225, I, 120, W1, 110), identifying, by the image processing unit 225 within the image capture device 205, within the image I, the road marking 120 projected on the road corresponding to the pulsed light beam W1, in order to distinguish the lane marked on the road 110 and the road marking 120 projected on the road.

[0115] In one non-limiting embodiment, the image capture device 205 has an acquisition frequency fq1 and the lighting module 215 has a pulsing frequency fq2 lower than the acquisition frequency fq1.

[0116] In one non-limiting embodiment, the pulsing frequency fq2 is a divisor of the acquisition frequency fq1.

[0117] Figure 7 is a flowchart of a method 2 for synchronizing the operation of a lighting module 215 of a motor vehicle with an image capture device 205 coupled to the motor vehicle, according to an embodiment of the application. The steps of the method will be described with reference to the components described in Figure 2 . Additional steps, different steps, or fewer steps can be provided. Steps can be performed in an order other than the order presented herein. As previously explained with reference to Figure 2 , the operation of the image capture device 205 and the lighting module are operated synchronously in a first mode and a second mode.

[0118] In a step S410, the image capture device 205 acquires an image of the road on which the vehicle is traveling in a time interval T1. In a step S420, the lighting module 215 projects a road marking on the road. In a step S430, the method comprises, in the first mode, deactivating the lighting module 215 by the control unit 220 and simultaneously activating the image capture device 205. In a step S440, the method comprises, in the second mode, activating the lighting module 215 by the control unit 220 and simultaneously deactivating the image capture device 205.

[0119] In the first mode, the image capturing device 205 is configured to send a synchronization signal to the control unit 220 on the rising edge of the pulse. Further, the control unit 220 is configured to send a deactivation signal to the illumination module 205 upon receiving the synchronization signal, and the image capturing device 205 is configured to capture an image during a time interval T1. The time interval T1 corresponds to the integration time, which is the duration of the image capturing. The captured image is then processed by the image processing unit 225 to calculate the position of the marked lane 210 on the road. In particular, the image processing unit 225 calculates the coordinates of the marked lane 110 on the road. Calculating the coordinates of the marked lane on the road by processing the image is well known to the person skilled in the art, and therefore the details of the calculation are not provided herein. Further, the coordinates of the marked lane 110 on the road are sent to the control unit 220.

[0120] While in the second mode, the image capturing device 205 is configured to send a synchronization signal to the control unit 220 on the falling edge of the pulse. The control unit 220 is configured to send an activation signal to the illumination module 205 upon receiving the synchronization signal, and the illumination module 205 is configured to project road markings on the road during a predetermined time interval T2. The illumination module 215 projects the markings on the road based on the calculated lane coordinates. The time interval T2 corresponds to the operation time of the illumination module. The size of the time interval T2 is set such that the driver of the vehicle can always see the marked lane 110 on the road without any flickering.

[0121] In step S450, the synchronization process between the illumination module 210 and the image capturing device 205 is repeated during the vehicle driving time T.

[0122] Thus, the image capturing device 210 operates in synchronization with the illumination module 215 such that during the operation of the image capturing device 205, the illumination module 210 does not project road markings 120 on the road, so that the marked lane 110 on the road can be identified without any confusion. Therefore, in an autonomous vehicle, the ADAS system that navigates the vehicle can easily identify the marked lane 120 on the road to navigate. Similarly, by projecting the road markings 120 based on the identification of the marked lane 110 on the road, the driver of the autonomous vehicle can easily identify whether there is enough space to pass or overtake other vehicles, so that accidents can be prevented.

[0123] It should be understood that the present application is not limited to the above-described embodiments and can be varied and modified without departing from the scope of the present application. In this regard, the following is stated. Thus, in one non-limiting embodiment, the road markings 120 are projected by the illumination module 215 by a pulsed light beam W1:

[0124] - for the first non-limiting embodiment, wherein the position p2 of the projected road marking 120 is used to distinguish said projected road marking 120 from the marked lane 110 on the road; and

[0125] - for the third non-limiting embodiment, wherein the lighting module 215 is deactivated at the same time as the image capturing device 205 is activated, and vice versa.

Claims

1. A lighting system (200) of a motor vehicle, the lighting system comprising: - an image capturing device (205) configured to acquire an image (I) of a road (R) on which the vehicle is travelling, the road (R) comprising a marked lane (110) on the road; - a lighting module (215) configured to project road markings (120) on the road (R); - a control unit (220); wherein the lighting system (200) is configured to filter the road markings (120) projected on the road in contrast with the marked lane (110) on the road, the lighting module (215) is configured to project road markings (120) on the road using a pulsed light beam (W1) and the image capturing device (205) is further configured to identify, in the image (I), the road markings (120) projected on the road corresponding to the pulsed light beam (W1) in order to distinguish the marked lane (110) on the road from the road markings (120) projected on the road, the image capturing device (205) has an acquisition frequency (fql) and the lighting module (215) has a pulsing frequency (fq2) which is lower than the acquisition frequency (fql), the pulsing frequency (fq2) is a divisor of the acquisition frequency (fql).

Images