The invention relates to a method for monitoring a lighting system of a vehicle, in particular of a utility vehicle, wherein the vehicle comprises an environment monitoring system with a camera device. The invention further relates to an electronic control unit, to a vehicle, in particular to a utility vehicle, and to a computer program.

Vehicle lighting systems play an integral role in vehicle safety. Typically, such a lighting system comprises one or more light sources to emit light into an environment of the vehicle. A failure and/or disfunction of the light source may lead to discomfort, dangerous situations and/or accidents. Hence, for driving safety it is important to have a mechanism to monitor the light health and to enable an identification of a failure and/or disfunction of the lighting system.

WO 2019/219454 A1 discloses a method for monitoring, from a traction vehicle, a lighting system of a trailer with first lights comprising at least one brake light, at least one right tail light, at least one left tail light, at least one rear fog light and/or at least one reversing light, wherein the first lights are supplied with electricity from the traction vehicle via electric circuits, and wherein during the monitoring of the lighting system of the trailer, each of the first lights is periodically checked with a first waiting time, the check determining whether the electric circuit having the first light to be checked is closed or not, wherein the first waiting time between two checks of one of the first lights is extended incrementally starting from an initial value for each individual first light if the electric circuit through this first light is not interrupted.

Similarly, DE 20 2010 005 782 U1 discloses a vehicle lighting monitoring device.

DE 10 2019 133 172 A1 discloses a system and a method for checking the state of at least one component on a vehicle, in particular a utility vehicle, comprising: a detection device which detects information in the form of a data set in a defined region on the vehicle, said defined region comprising the at least one component to be checked, and an analysis device which is provided with the data set, wherein the analysis device is configured so as to ascertain the state of the at least one component using the detected data set, and the detection device is secured to the vehicle and/or is carried by the vehicle at least temporarily. Therein, the detected data set may comprise an optically acquired image so that a comparison with one or more target images may be performed to check the state of the component. The detection device may comprise a camera or a light sensor.

It is an object of the present invention to provide a technological contribution and to improve at least one aspect of the prior art. In particular, an object of the invention may be to enable an efficient and reliable identification of a failure and/or disfunction of a lighting system.

The object is solved by the subject-matter according to independent claim 1 and according to the remaining independent claims. Dependent claims relate to preferred embodiments.

According to an aspect of the invention, a method for monitoring a lighting system of a vehicle, in particular of a utility vehicle, is provided. Therein, the vehicle comprises an environment monitoring system with a camera device. The method comprises the steps of: obtaining, from the camera device, an image, relating to a light beam of the lighting system; comparing the image with a reference image, wherein the reference image was obtained by the camera device; and outputting, based on comparing the image with the reference image, a monitoring signal relating to the lighting system.

In the following, the vehicle, in particular utility vehicle, will be referred to as vehicle. The lighting system of the vehicle comprises one or more light sources, i.e., lamps.

By the one or more lamps the lighting system is adapted to emit light into the environment of the vehicle. The light which is emitted by the lighting system into the environment of the vehicle may be optically and/or visibly perceivable as a light beam in the environment of the vehicle. The environment monitoring system of the vehicle may be any system of the vehicle which is capable to optically monitor the environment of the vehicle. The environment monitoring system is adapted to obtain the image of the light beam. According to the method, the image is compared with the reference image. Therein, the image and the reference image are comparable to each other as each of the image and the reference image was obtained by the camera device. The reference image was obtained before the image is obtained to provide a basis for comparing the image with the reference image. The image and the reference image are compared to each other by image processing.

Comparing the image with the reference image is performed to obtain the monitoring signal. The monitoring signal characterizes the lighting system by potential differences between the image and the reference image which has been compared to each other. The monitoring signal may thus be used to indicate the degradation of the functionality of the lighting system. Therein, the comparison leads to a reliable monitoring signal since the reference image and the image are obtained by the same camera device.

In other words, the method proposes an approach to monitor the degradation of the lighting system and may thereby give an indication of upcoming failures. The method may be performed by using existing systems and devices of the vehicle to capture the image of the immediate ground ahead the vehicle, wherein the ground is illuminated by the vehicle’s lighting system. The images are captured to identify a degradation of the lighting system by monitoring the light beam, e.g., an intensity thereof, using vision compute algorithms. Therein, it is realized that camera devices, such as a rear camera, e.g., for a reverse parking system, a camera of an advanced driver assistance system (ADAS) and/or a dash camera, are typically comprised by the vehicle. Furthermore, the presence of a reverse parking camera, an ADAS, and/or a dash camera may be mandated by regulations. It is possible, by monitoring the degradation, to detect an onset and/or progress of light degradation using a vision compute system. The proposed method is aimed at improving the lighting system of the vehicle and may improve aspects of maintenance and replacement activities of the vehicle lighting system.

Preferably, the image is obtained by a front-facing camera. The front facing camera may be a dash cam and/or a camera of a safety system of the vehicle, i.e., a camera of an advanced driver assistance system (ADAS). The environment monitoring system comprises the front-facing camera. With the front-facing camera it is possible to monitor a head light of the lighting system. Additionally or alternatively, the image is obtained by a rear view camera, i.e., a reverse camera and/or a camera of a parking assistant. The environment monitoring system comprises the rear view camera. With the rear view camera, it is possible to monitor a reversing light of the lighting system. The environment monitoring system may comprise the front-facing camera and the rear view camera to monitor the headlight and the reversing light.

Preferably, comparing the image with the reference image comprises determining an intensity profile of the light beam in each of the image and the reference image. The intensity profile characterizes the light beam and is, by image processing, determinable from each of the image and the reference image. Therein, the intensity profile may relate to a brightness of one or more pixels of each of the image and the reference image, and/or to a line, i.e., contour, that characterizes the light beam and/or its brightness within each of the image and the reference image. Additionally or alternatively to the brightness, a color information, which relates to the color of the light beam may be considered to determine the intensity profile.

Preferably, the image of the light beam is obtained so that the image comprises a reflection of the light beam on a road surface. The environment monitoring system is adapted to monitor the road surface within the environment of the vehicle. This embodiment enables an effective acquisition of image data to characterize the light beam. In this embodiment, additional camera devices which monitor a light source of the lighting system may be dispensed with.

Preferably, the image is obtained under pre-determined environment conditions. The pre-determined condition may be pre-determined by environment conditions as being present when the reference image and/or a previous image was obtained. This improves comparing the image with the reference image. To maintain similar environment conditions, images may be obtained at a fixed time, e.g., when daylight is not present, and a fixed place, e.g., garage.

Preferably, outputting the monitoring signal comprises a gradual light performance indicator. Thus, the monitoring signal comprises the gradual light performance indicator which is determined based on comparing the image with the reference image. The gradual light performance indicator may be obtained by image processing, e.g., on the basis of a difference in an intensity and/or color between the image and the reference image. The gradual light performance indicator may enable a more effective and gradual indication of the functioning and/or degradation of the lighting system. The gradual light performance indicator may comprise one or more numbers, for example, in a pre-determined interval to gradually indicate the performance of the lighting system. For example, the pre-determined interval may range from 0 to 1 and the gradual light performance indicator may take any value within the interval. As another example, the pre-determined interval, may range from 0 to 100 and the gradual light performance indicator may take any integer in the pre-determined interval.

Preferably, the method comprises the steps of: comparing the gradual light performance indicator with an indicator threshold; and transmitting, in dependence on comparing the gradual light performance indicator with the indicator threshold, a warning message to a user interface of the vehicle, to a vehicle external server and/or to a user terminal device. The indicator threshold may be a pre-determined number. The indicator threshold may be pre-determined in dependence of the reference image and/or by a fleet management system. Comparing the gradual light performance indicator with the indicator threshold may result in an indication whether the lighting system is functional or its function is degraded. For example, if the gradual light performance indicator is less than the indicator threshold, the performance of the lighting system is degraded and the warning message may be issued. Otherwise, the performance of the lighting system is reasonable and the warning message may be dispensed with. The warning message may be issued by transmitting the warning message to the user interface to inform a user and/or a driver of the vehicle, to the user terminal device to inform the user and/or the driver of the vehicle, and/or to an external server to inform a service provider, e.g., a fleet provider. Therein, the user interface may comprise any output device of the vehicle. The user terminal device may be a handheld device of a user, such as a smart phone, a tablet and/or a computer. The external server may be a server of a fleet management system. The warning message is transmitted to inform about the performance of the lighting system. Preferably, the method comprises the step of: periodically transmitting a status message relating to the light performance indicator to a user interface of the vehicle, to a vehicle external server and/or to a user terminal device. Periodically transmitting the status message may enhance monitoring the performance of the lighting system. This may enable scheduling maintenance of the lighting system and/or predicting that an upcoming outage and/or disfunction will occur before the outage and/or disfunction occurs. The period for periodically transmitting the status message may be determined by a fleet management system and/or by the light performance indicator, e.g., if the lighting system is about to degrade, the period may be shorter than if the lighting system is new.

According to another aspect of the invention, an electronic control unit for a vehicle, in particular utility vehicle, is provided. The electronic control unit comprises a transceiver configured to transmit and receive signals, and a controller configured to perform the method steps of the method as described herein. The electronic control unit may be and/or comprise a vehicle telematics device. The electronic control unit may be configured to perform any of the optional and/or preferred method steps to achieve a technical effect which corresponds therewith.

According to another aspect of the invention, a vehicle, in particular a utility vehicle, is provided. The vehicle comprises a lighting system, the environment monitoring system with a camera device and the electronic control unit as described herein. The electronic control unit may be and/or comprise a vehicle telematics device. The electronic control unit may be configured to perform any of the optional and/or preferred method steps to achieve a technical effect which corresponds therewith. The environment monitoring system comprises a camera device which is adapted to acquire an image relating to a light beam of the lighting system.

According to another aspect of the invention, a computer program is provided. The computer program comprises instructions which, when the program is executed by a controller, causes the controller to carry out the method according to the invention. Preferably, the computer program comprises instructions, when the program is executed by a controller, causes the controller to carry out a preferred and/or optional methods step as descried herein to achieve technical effects associated therewith. Further advantages and technical features and their technical effects are disclosed in the figures and the description thereof.

The figures show preferred embodiments as follows:

Fig. 1 a schematic top view of a vehicle, in particular a utility vehicle, according to an embodiment of the invention;

Fig. 2 a schematic of an image as being obtained by a camera device of a vehicle, in particular a utility vehicle, according to an embodiment of the invention;

Fig. 3 a schematic of a method according to an embodiment of the invention;

Fig. 4 another schematic of a method for monitoring a lighting system according to an embodiment of the invention; and

Fig. 5 a schematic of an electronic control unit according to an embodiment of the invention.

Figure 1 shows a schematic top view of a vehicle 300a, in particular a utility vehicle 300b, according to an embodiment of the invention. In the following, the vehicle 300a, in particular utility vehicle 300b, is referred to as vehicle 300a, 300b.

The vehicle 300a, 300b is arranged in an environment 291 of the vehicle 300a, 300b. The environment 291 is an exterior, i.e., a surrounding of the vehicle 300a, 300b. The vehicle 300a, 300b is arranged on a road surface 290 which is schematically indicated by a box with a dashed line. The environment 291 may be characterized by environment conditions 295. The environment conditions 295 may comprise an information regarding a weather condition, a time, a condition relating to light within the surrounding 291 , a condition relating to the road surface 290 and/or a condition relating to the reflectivity of the road surface 290.

The vehicle 300a, 300b comprises an electronic control unit 320. Each of the vehicle 300a, 300b and the electronic control unit 320 is adapted to perform the method 100 as described with reference to Figures 3 and 4. The electronic control unit 320 is further described with reference to Figure 5. As shown in Figure 1 , the vehicle 300a, 300b comprises a lighting system 200. The lighting system 200 comprises a head light 201 and a reversing light 202. Each of the head light 201 and the reversing light 202 is adapted to emit light into the environment 291 of the vehicle 300a, 300b. The light which is emitted by the lighting system 200 leads to a reflection 210 of the emitted light which is visible as a light beam 205. Specifically, the light which is emitted by the head light 201 leads to a front light beam 206 which is arranged in a front of the vehicle 300a, 300b. The light which is emitted by the reversing light 202 leads to a rear light beam 207 which is arranged behind the vehicle 300a, 300b. To emit light, the lighting system 200 comprises light sources (not indicated). The light sources comprise one or more light emitting devices, such as a light bulb and/or an LED.

The vehicle 300a, 300b comprises an environment monitoring system 250. The environment monitoring system 250 comprises two camera devices 255. The environment monitoring system 250 and the camera device 255 are adapted to acquire an image 260 as described with reference to Figure 2.

As shown in Figure 1 , the environment monitoring system 250 comprises a front-facing camera 256 and a rear-view camera 257. Le., the two camera devices 255 are the front-facing camera 256 and the rear-view camera 257. Each of the camera devices 255 is adapted to acquire an image 260 of the environment 291 of the vehicle 300a, 300b. Specifically, the front-facing camera 256 is adapted to acquire an image 260 of the environment 291 in the front of the vehicle 300a, 300b and the rear-view camera 257 is adapted to acquire an image 260 of the environment 291 behind the vehicle 300a, 300b. The front-facing camera 256 is adapted to acquire an image 260 relating to the front light beam 206. The rear-view camera 257 is adapted to acquire an image 260 relating to the rear light beam 207. Thus, the images 260 of each of the light beams 205 are acquired so that the images 260 comprise the reflection 210 of the respective light beam 205 on the road surface 290.

The environment monitoring system 250, i.e., each of the two camera devices 255, i.e., each of the front-facing camera 256 and the rear-view camera 257, is connected to the electronic control unit 320 to transmit the image 260 to the electronic control unit 320. The electronic control unit 320 is adapted to obtain the image 260 from the camera devices 255.

As described further with reference to Figure 5 and Figure 3, the electronic control unit 320 comprises a controller 322 (not shown in Figure 1 ) to perform image processing 150 of the image 260. As indicated in Figure 1 , the controller 320 performs comparing 120 the image 260 with a reference image 265, wherein the reference image 265 was obtained by the camera devices 255 and transmitted to the electronic control unit 320. Therein, comparing 120 the image 260 with the reference image 265 comprises determining 125 an intensity profile 275 of the light beam 205 in each of the image 260 and the reference image 265. The intensity profile 275 may be stored, as indicated schematically by a dashed box, and/or be processed by the electronic control unit 320.

As described further with reference to Figure 5 and Figure 4, the electronic control unit 320 of Figure 1 comprises a transceiver 321 (not shown in Figure 1 ) which is adapted to transmit a monitoring signal 270, a gradual light performance indicator 276, a warning message 280 and/or a status message 280 to a user interface 310 of the vehicle 300a, in particular utility vehicle 300b, to a vehicle external server 400, e.g., a cloud server, and/or to a user terminal device 410, e.g., a mobile. Therein, the warning message 280 is transmitted in dependence on comparing 120a the gradual light performance indicator 276 with the indicator threshold 277. The indicator threshold 277 may be stored, as indicated schematically by a dashed box, by the electronic control unit 320. In other words, the electronic control unit 320 comprises a telematics gateway which acts as a mediator between the internal vehicle environment and the external environment, and acts as a host for the intelligence to run on.

Figure 2 shows a schematic of an image 260 as being obtained from a camera device 255. The image 260 illustrates a road surface 290 of a road (not indicated) in an environment 291 of a vehicle 300a, 300b that comprises the camera device 255. The environment 291 is characterized by an environment condition 295. The environment condition 295 is characterized by a degree of darkness and/or brightness of the environment 295. A light beam 205 in form of a front light beam 206 is visibly perceivable as a reflection 210 of the light beam 205 on the road surface 290. Thus, image information relating to the light beam 205 is acquired through the camera device 255 by acquiring the image 260. The image 260 may be obtained by an electronic control unit 320 for further processing as explained with reference to Figures 1 , 3 and 4.

Figure 3 shows a schematic of a method 100 according to an embodiment of the invention. The method 100 is a method 100 for monitoring a lighting system 200 of a vehicle 300a, 300b as described with reference to Figure 1 . Figure 3 is described under reference to Figures 1 and 2 and the description thereof.

The method 100 comprises the step of obtaining 110, from the camera device 255, the image 260, relating to the light beam 205 of the lighting system 200. The image 260 is obtained by the front-facing camera 256 and/or by the rear-view camera 257. The image 260 is obtained under pre-determined environment conditions 295.

The method 100 comprises comparing 120 the image 260 with the reference image 265, wherein the reference image 265 was obtained by the camera device 255. The image 260 and the reference image 265 may have been obtained, i.e., acquired, under comparable environment conditions 295, e.g., the environment condition 295 under which the reference image 265 has been obtained determines the pre-determined environment conditions 295 to obtain the image 260.

The method 100 comprises comparing 120a the gradual light performance indicator 276 with an indicator threshold 277. Using image processing 150 techniques, the gradual light performance indicator 276 is obtained on the basis of the image 260 and the intensity and/or color of one or more pixels in the captured image 260. The gradual light performance indicator 276 characterizes the degradation of the performance of the lighting system 200 compared to the performance of the lighting system 200 as being obtainable from the reference image 265. The indicator threshold 277 is a value to compare the gradual light performance indicator 276 with.

Comparing 120 the image 260 with the reference image 265 comprises determining 125 an intensity profile 275 of the light beam 205 in each of the image 260 and the reference image 265. By comparing 120 the image 260 with the reference image 265, the gradual light performance indicator 276 is determined.

The method 100 comprises outputting 130, based on comparing 120 the image 260 with the reference image 265, the monitoring signal 270 relating to the lighting system 200. Outputting 130 the monitoring signal 270 comprises outputting the gradual light performance indicator 276. The monitoring signal 270 is output to indicate the degradation of the functionality of the lighting system 200. Outputting 130 the monitoring signal 270 may comprise providing the monitoring signal 270 for further transmitting 135, 135a a signal, a message, a notification and/or a warning.

The method 100 comprises transmitting 135, in dependence on comparing 120a the gradual light performance indicator 276 with the indicator threshold 277, a warning message 280 to a user interface 310 of the vehicle 300a, 300b, to the vehicle external server 400 and/or to the user terminal device 410.

The method 100 comprises periodically transmitting 135a a status message 285 relating to the light performance indicator 276 to a user interface 310 of the vehicle 300a, 300b, to the vehicle external server 400 and/or to the user terminal device 410.

The skilled person realizes that steps of the method 100 may be performed in another order as illustrated in Figure 3 and/or simultaneously. For example, obtaining 110 the image 260 may be performed continuously, e.g., while other steps of the methods 100 are performed. The steps of outputting 130 the monitoring signal, of transmitting 135 the warning message 280 and of periodically transmitting 135a the status message 285 may be performed in an arbitrary order and/or simultaneously.

Figure 4 shows another schematic of a method 100 for monitoring a lighting system 200 according to an embodiment of the invention. Figure 4 is an alternative representation of the method 100 as shown and described with reference to Figure 3.

In Figure 4, an environment monitoring system 250, an electronic control unit 320, a user interface 310, a server 400 and a user terminal device 410 are indicated by a box in a column, wherein in each of the columns respective method steps and/or information is depicted. Therein, the interrelation between the environment monitoring system 250, the electronic control unit 320, the user interface 310, the server 400 and the user terminal device 410 is indicated by arrows between the columns. Each of the environment monitoring system 260, the electronic control unit 320, the user interface 310, the server 400 is described with reference to Figures 1 and/or 5.

The environment monitoring system 250 acquires the image 260 as shown in Figure 2. The environment monitoring system 250 transmits the image 260 to the electronic control unit 320 at which the image 260 is obtained 110. The environment monitoring system 250 makes use of an ADAS front camera and/or a rear camera to capture the image 260 of the immediate ground ahead illuminated by the vehicle’s lighting system 200.

The electronic control unit 320 is adapted to perform image processing 150. The image 260 is to be processed by an algorithm deployed in the electronic control unit 320. By image processing 150, the algorithm shall measure the light intensity in the image 260 under the light of the lighting system 200. Using image processing 150 techniques as per the respective color spaces used by the cameras 255, the algorithm determines the brightness of the pixels in the captured image 260.

The electronic control unit 320 obtains and/or loads, from a data memory, the reference image 265, wherein the reference image 265 was obtained by the camera device 255. The first ever image captured on a new vehicle 300a, 300b may be used as the reference image 265 against which the images 260 captured later are compared. To maintain similar external conditions, the system may capture the image 260 at a fixed time, e.g., when daylight is not available, and fixed place, e.g., at garage at frequent intervals.

The electronic control unit 320 performs comparing 120 the image 260 with the reference image 265. The electronic control unit 320 performs comparing 120a the gradual light performance indicator 276 with the indicator threshold 277. When the algorithm finds that there is a noticeable deterioration in the illumination and/or brightness of the captured image 260 under similar conditions, it issues an alert, i.e., the warning message 280, relating to a suspected onset of degradation in the lighting system 200.

The alert is given via the electronic control unit 320 on which the algorithm is running. The electronic control unit 320 performs outputting 130, based on comparing 120 the image 260 with the reference image 265, the monitoring signal 270 relating to the lighting system 200. Thus, the electronic control unit 320 transmits the monitoring signal 270 to the user interface 310, the server 400 and the user terminal device 410 to be output. The electronic control unit 320 performs transmitting 135, in dependence on comparing 120a the gradual light performance indicator 276 with the indicator threshold 277, the warning message 280 to the user interface 310, to the vehicle external server 400 and/or to the user terminal device 410.The electronic control unit 320 performs periodically transmitting 135a the status message 285 relating to the light performance indicator 276 to the user interface 310 of the vehicle 300a, 300b, to the vehicle external server 400 and/or to the user terminal device 410. The driver and/or fleet manager can plan maintenance and/or replacement activities based on these alerts and/or status messages 185.

Figure 5 shows a schematic of an electronic control unit 320 according to an embodiment of the invention. The electronic control unit 320 is adapted to be comprised by a vehicle 300a, in particular utility vehicle 300b, as described with reference to Figure 1 . The electronic control unit 320 comprises a transceiver 321 configured to transmit and receive signals, and a controller 322 configured to perform the method steps of the method 100 as described with reference to Figure 3 and 4.

The transceiver 321 may transmit and receive signals to and from another device, e.g., to and from a camera device 255, a user interface 310 of the vehicle 300a, vehicle 300b, a vehicle external server 400 and/or a user terminal device 410. The transceiver 201 is adapted to perform communication by exchanging signals with, for example, the camera device 255, the user interface 310, the vehicle external server 400 and/or the user terminal device 410.

The controller 322 comprises a circuit, an application-specific integrated circuit, at least one processor and/or a memory. The controller 322 is adapted to control the overall operation of the electronic control unit 320, e.g., is adapted to perform the method steps of the method 100 as described with reference to Figures 3 and 4. The memory may store at least one of information transmitted and received through the transceiver 321 , information generated through the controller 322 and/or a computer program, comprising instructions which, when the program is executed by the controller 322, causes the controller 322 to carry out the method 100 as described with reference to Figures 3 and 4.

Reference Signs Part of the description:

100 method

110 obtaining

120 comparing

120a comparing

125 determining

130 outputting

135 transmitting

135a transmitting

150 image processing

200 lighting system

201 head light

202 reversing light

205 light beam

206 front light beam

207 rear light beam

210 reflection

250 environment monitoring system

255 camera device

256 front-facing camera

257 rear view camera

260 image

265 reference image

270 monitoring signal

275 intensity profile

276 gradual light performance indicator

277 indicator threshold

280 warning message

285 status message

290 road surface

291 environment

295 environment condition a vehicle b utility vehicle user interface electronic control unit transceiver controller server user terminal device