FR3129911A1 - Method and device for controlling a driver assistance system - Google Patents

Abstract

The present invention relates to a method and a device for controlling a vehicle driving assistance system. To this end, first data representative of an availability or unavailability of a radar signal are received (31) from at least one radar on board the vehicle. When the radar signal is unavailable, the reception of data from the driver assistance system is switched (32) to a camera signal received from at least one on-board camera in the vehicle and the driver assistance system is controlled ( 33) depending on the camera signal. When the radar signal is available, data reception is switched (34) to the radar signal and the driver assistance system is controlled (35) according to the radar signal. Figure for abstract: Figure 3

Description

Method and device for controlling a driver assistance system

The present invention relates to methods and devices for assisting the driving of a vehicle. The present invention also relates to a method and a device for switching between the reception of road environment data of several signals. The present invention also relates to a method and a device for switching the reception of road environment data from a device on board a vehicle, in particular an autonomous vehicle. The present invention also relates to a method and a device for controlling a device for receiving road environment data.

Technology background

Road safety is an important issue for our societies. With the increase in the number of vehicles on road networks around the world, regardless of traffic conditions, the risks of accidents and incidents caused by traffic conditions have never been greater.

To improve road safety, some contemporary vehicles are equipped with driving assistance functions or systems, known as ADAS (from the English "Advanced Driver-Assistance System" or in French "Advanced Driving Assistance System") . ADAS systems, for example, implement methods based on the detection of surrounding obstacles using peripheral sensors on board a vehicle such as cameras, radars, or even lidars (from the English "Light Detection And Ranging" , or “Detection and estimation of distance by light” in French).

ADAS systems can also take account of navigation data indicating in advance the characteristics of a road, in particular speed limits, coasts or even the radius of curvature of bends on the route, so as to optimize the driving of the vehicle in advance. vehicle.

For their operation, a plurality of ADAS systems require information derived specifically from radar data, allowing them to detect the objects located around the vehicle and their distances vis-à-vis the vehicle. This plurality of ADAS systems includes in particular adaptive cruise control systems, known as ACC (from the English “Adaptive Cruise Control” also called “distance control radar”), positioning assistance systems in a traffic queue , known as LPA (from the English “Lane Positioning Assist”) and systems for assisting in keeping in a traffic queue, known as LKA (from the English “Lane Keeping Assist”).

In the event of a malfunction of the radar(s) on board the vehicle, these ADAS systems are then deactivated for the time to recover access to the radar data, regardless of the situation. Abrupt deactivation of ADAS functions while driving a vehicle thus represents a loss of comfort for the driver and a substantial risk for all road users.

Summary of the present invention

An object of the present invention is to solve at least one of the disadvantages of the technological background.

Another object of the present invention is to avoid as much as possible the deactivation of ADAS functions during driving.

According to a first aspect, the present invention relates to a method for controlling a driver assistance system of a vehicle traveling in a road environment, the method comprising the following steps:

- reception of first data representative of the availability or unavailability of a radar signal, from at least one radar on board the vehicle;

when the radar signal is unavailable:

- first switching to a camera signal received from at least one camera on board the vehicle;

- first control of the driving assistance system according to the camera signal;

when the radar signal is available:

- second switching to the radar signal;

- second control of the driving assistance system according to the radar signal.

According to a variant, the first check comprises the following steps:

- reception of second data representative of the road environment;

- determination of representative characteristics of at least one object associated with the road environment as a function of the second data; And

- control of the driving assistance system according to the representative characteristics.

According to another variant, the determination of characteristics comprises the following steps:

- determination of spatial coordinates associated with the at least one object from a visual representation of the road environment resulting from the second data;

- determination of dimensions associated with the at least one object from the coordinates; And

- determination of a distance between the vehicle and the at least one object from the dimensions and third data representative of the at least one object, the third data being received from a memory on board the vehicle.

According to an additional variant, the determination of characteristics further comprises a determination of a speed associated with the at least one object from a plurality of determined values of the distance.

According to yet another variant, the second check is carried out as a function of the radar signal and of the camera signal.

According to an additional variant, the first data comprises information representative of a duration of unavailability of the radar signal, the first switching and the second switching being carried out according to a result of a comparison of the duration of unavailability with a threshold value.

According to a second aspect, the present invention relates to a device for controlling a vehicle driving assistance system, the device comprising a memory associated with a processor configured for the implementation of the steps of the method according to the first aspect of the present invention.

According to a third aspect, the present invention relates to a vehicle, for example of the automobile type, comprising a device as described above according to the second aspect of the present invention.

According to a fourth aspect, the present invention relates to a computer program which comprises instructions adapted for the execution of the steps of the method according to the first aspect of the present invention, this in particular when the computer program is executed by at least one processor.

Such a computer program can use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

According to a fifth aspect, the present invention relates to a computer-readable recording medium on which is recorded a computer program comprising instructions for the execution of the steps of the method according to the first aspect of the present invention.

On the one hand, the recording medium can be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM memory, a CD-ROM or a ROM memory of the microelectronic circuit type, or even a magnetic recording means or a hard disk.

On the other hand, this recording medium can also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or hertzian radio or by self-directed laser beam or by other ways. The computer program according to the present invention can in particular be downloaded from an Internet-type network.

Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to execute or to be used in the execution of the method in question.

Brief description of figures

Other characteristics and advantages of the present invention will emerge from the description of the particular and non-limiting examples of embodiments of the present invention below, with reference to the appended figures 1 to 3, in which:

schematically illustrates a vehicle traveling in a road environment, according to a particular and non-limiting embodiment of the present invention;

schematically illustrates a device configured for controlling a driver assistance system of the vehicle of the , according to a particular and non-limiting embodiment of the present invention;

illustrates a flowchart of the different steps of a method for controlling a driver assistance system of the vehicle of the , according to a particular and non-limiting embodiment of the present invention.

Description of the examples of realization

A method and a device for controlling a vehicle driving assistance system will now be described in the following with reference in conjunction with FIGS. 1 to 3. The same elements are identified with the same reference signs throughout the following description.

According to a particular and non-limiting embodiment of the present invention, a method for controlling a driving assistance system, called ADAS system, of a vehicle traveling in a road environment comprises the reception, by the vehicle, first data representative of an availability or unavailability of a radar signal. In other words, the first data tells the vehicle whether a radar signal can be used to control the driver assistance system. The first data is received from at least one radar on board the vehicle, for example a radar associated with the ADAS system. It is understood here that the on-board radar corresponds to any on-board device configured to detect the obstacles around the vehicle and their distances vis-à-vis the vehicle, for example a millimeter wave radar or else a sensor of the LIDAR type.

The first data thus enable the vehicle to determine whether the radar signal is available or unavailable. When the radar signal is unavailable, the vehicle performs a first switching from the reception of environment data to a camera signal received from at least one camera on board the vehicle and controls the driving assistance system according to the camera signal . Such control corresponds for example to so-called "degraded mode" operation of the ADAS system, making it possible to maintain its operation despite the unavailability of the radar signal by extracting the necessary environmental data from an alternative source. The vehicle for example processes the data from the camera signal so as to detect and/or obtain information on the obstacles around the vehicle and obtain their distances from the vehicle, for example in order to update the status of objects identified at a time when the radar signal was available.

When the radar signal is available, the vehicle performs a second switch from receiving environmental data to the radar signal and controls the ADAS system based on the radar signal. Such a control corresponds, for example, to so-called “normal mode” operation of the ADAS system, using the environmental data necessary for its proper operation according to its initial configuration.

Such a method thus makes it possible to maintain the operation of the ADAS system or systems of the vehicle despite the unavailability of the main signal normally necessary for their operation, pending the return to normal operation of the on-board radar for optimal operation of the ADAS systems. Maximizing the availability of ADAS systems thus increases the comfort and safety of the driver of the vehicle equipped with ADAS systems as well as of other road users.

schematically illustrates a vehicle 11 traveling in a road environment 1, according to a particular embodiment of the present invention.

There illustrates a road environment 1 comprising for example a traffic lane 1000 on which a first vehicle 11 travels. a heat engine and one or more electric motors. The first vehicle 11 thus corresponds for example to a land vehicle, for example an automobile, a truck, a coach.

In accordance with the underlying concept of the invention, the vehicle 11 embeds one or more driving assistance systems, called ADAS systems, allowing the vehicle 11 to be driven autonomously or semi-autonomously.

The level of autonomy of an autonomous vehicle is for example between 0 and 5 (0 for a vehicle having no autonomy and whose driving is under the full supervision of the driver and 5 for a completely autonomous vehicle).

The 5 levels of autonomy of the classification of the federal agency in charge of road safety are:

- level 0: no automation, the driver of the vehicle fully controls the main functions of the vehicle (engine, accelerator, steering, brakes);

- level 1: driver assistance, automation is active for certain vehicle functions, the driver retaining overall control over the driving of the vehicle; cruise control is part of this level, like other aids such as ABS (anti-lock braking system) or ESP (programmed electro-stabilizer);

- level 2: automation of combined functions, the control of at least two main functions is combined in the automation to replace the driver in certain situations; for example, adaptive cruise control combined with lane centering allows a vehicle to be classified as level 2, as does automatic parking assistance;

- level 3: limited autonomous driving, the driver can hand over complete control of the vehicle to the automated system which will then be in charge of critical safety functions; however, autonomous driving can only take place under certain determined environmental and traffic conditions (only on the motorway, for example);

- level 4: complete autonomous driving under conditions, the vehicle is designed to carry out all the critical safety functions on its own over a complete journey; the driver provides a destination or navigation instructions but is not required to make himself available to regain control of the vehicle;

- level 5: completely autonomous driving without driver assistance in all circumstances.

The classification of the International Organization of Motor Vehicle Manufacturers is similar to that listed above, with the difference that it has 6 levels, level 3 of the American classification being divided into 2 levels in that of the International Organization of Car manufacturers.

In a first operation, at least one processor of the vehicle 11, for example a central computer, a set of computers, or even a peripheral computer associated with the ADAS system of the vehicle 11, receives first data representative of an availability or unavailability of a radar signal.

The at least one processor comprises for example an intelligent service box or BSI (in English “Built-In Systems Interface”) or else VSM (from English “Vehicle Supervisor Module” or in French “Module de Supervision de Vehicule” ) capable of forming a communication network, for example a multiplexed communication network, in which data is transmitted via a wireless or wired link, for example data received from on-board sensors. The at least one processor or BSI (hereinafter referred to as “BSI”) is thus connected to a plurality of peripheral computers, for example to the peripheral computers associated with the on-board ADAS systems of the vehicle 11 and/or to other system computers boarded the vehicle 11.

The BSI thus receives data by communication in the multiplexed communication network allowing for example to control the ADAS system. The data received by the BSI are for example generated from data representative of the road environment 1, for example data obtained by one or more sensors of the object detection system(s) on board the vehicle 11, this or these systems being for example part of an ADAS system of the vehicle 11.

By way of example, the sensor(s) associated with these object detection systems correspond to one or more of the following sensors:

- one or more millimeter wave radars arranged on the vehicle 11, for example at the front, at the rear, on each front/rear corner of the vehicle 11; each radar being adapted to emit electromagnetic waves and to receive the echoes of these waves returned by one or more objects, with the aim of detecting obstacles and their distances vis-à-vis the vehicle 11; and or

- one or more LIDAR(s), a LIDAR sensor corresponding to an optoelectronic system composed of a laser transmitter device, a receiver device comprising a light collector (to collect the part of the light radiation emitted by the transmitter and reflected by any object located on the path of the light rays emitted by the transmitter) and a photodetector which transforms the collected light into an electrical signal; a LIDAR sensor thus makes it possible to detect the presence of objects located in the light beam emitted and to measure the distance between the sensor and each object detected; and or

- one or more cameras (associated or not with a depth sensor) for the acquisition of one or more images of the environment around the vehicle 11 located in the field of vision of the camera or cameras.

The data obtained from this or these sensors varies according to the type of sensor. When it is a radar or a LIDAR, the road environment datum 1 corresponds for example to distance data between points of the detected object and the sensor. Each detected object is thus represented by a cloud of points (each point corresponding to a point of the object receiving the radiation emitted by the sensor and reflecting at least part of this radiation), the cloud of points representing the envelope (or a part of the envelope) of the detected object as seen by the sensor and ultimately by the first vehicle 10 carrying the sensor. In the case of a video camera, the road environment datum 1 corresponds to data associated with each pixel of the acquired image or images, for example gray level values coded on for example 8, 10, 12 or more bits for each color channel, for example RGB (from English “Red, Green, Blue” or in French “Rouge, vert, bleu”). These data make it possible, for example, to determine the successive positions taken by an object moving in the environment 1 and to deduce therefrom one or more dynamic parameters of the moving object such as the speed and/or the acceleration and/or the presence and status of traffic lights.

Thus, the vehicle 11 embeds one or more radar(s) and/or LIDAR(s) configured to return a radar signal directly comprising information on the objects detected in the road environment 1 and their distance vis-à-vis the vehicle 11. One or more ADAS systems on board the vehicle 11, in particular ACC and/or LPA and/or LKA systems, directly use the data from the radar signal to control the longitudinal and/or lateral behavior of the vehicle 11.

The vehicle 11 additionally embeds at least one camera configured to return a camera signal, which is in normal operation used to determine additional dynamic parameters of the objects of the road environment 1, as described above.

The first data therefore correspond to data received from one or more radar(s) and/or LIDAR(s) (hereinafter jointly referred to as "radar") allowing the BSI to identify and/or date a fault radar.

According to a variant, the first data includes information representative of a duration of unavailability of the radar signal. The data received by the BSI are for example timestamped at each time step, the BSI following the data refresh status. The availability or unavailability of the radar signal then corresponds to the comparison of the duration of unavailability of the radar signal with a threshold value, for example a value recorded in a memory of the BSI and configurable. By way of example, the threshold value corresponds to a duration of two seconds, the radar signal being considered as unavailable if its associated duration of unavailability is greater than two seconds.

Obviously, other possible forms of first data are designed, for example directly comprising information representing a state of the radar and/or the BSI detecting unavailability of the radar associated with faulty operation.

The radar signal is therefore detected as available or unavailable by the BSI according to the first information.

When the radar signal is detected as unavailable, the BSI performs in a second operation a first switching to a camera signal received from at least one on-board camera, the ADAS system being controlled in a third operation according to the camera signal, corresponding to a first control. In other words, the first switching is performed according to the first data, for example when the unavailability duration is greater than the threshold value.

According to a variant, the first control comprises a step of receiving second data representative of the road environment 1. The second data comes from the camera signal in accordance with the first switching and comprises for example information representative of a visual representation of the road environment 1, corresponding to the field of vision of the at least one on-board camera.

The BSI then determines representative characteristics of at least one object 12 associated with the road environment 1, for example a second vehicle traveling on the traffic lane 1000, according to the second data and controls the ADAS system according to the representative characteristics . According to other examples, the object 12 corresponds to an element of the traffic lane 1000, for example a speed bump, a marking on the ground or even a traffic light. It is understood here that the representative characteristics correspond to parameters necessary for the operation of the ADAS system and usually obtained from the radar signal, for example the distance of the object 12 vis-à-vis the vehicle 11.

According to a particular embodiment, the BSI determines spatial coordinates associated with the object 12 from a visual representation of the road environment 1. The object 12 is for example located using a network of neurons of the CNN type (from the English “Convolutional Neural Network” or in French “Réseau deneurones convolutionifs”), the associated spatial coordinates corresponding for example to the maximum and minimum coordinates of a rectangle encompassing the object 12. The BSI determines then dimensions associated with the object 12 from the spatial coordinates, then a distance between the vehicle 11 and the object 12 from the dimensions and third data representative of the object 12 received from a memory on board the vehicle 11 The third data correspond for example to a previous determination of the characteristics of the object 12 carried out before the radio signal was unavailable or to a previous iteration of the determination of the characteristics representative of the object 12.

In this example, the object 12 is located in a reference (X, Y) of the visual representation of the road environment as being inside a rectangle defined by two pairs of values (x1, y1) and (x2, y2) corresponding for example to the upper left and lower right ends of the rectangle. The BSI then determines a width W of the object 12 defined by the formula W = x1 – x2 (equation 1). From the third data, the BSI obtains a previous width P obtained at a previous distance F, the distance D of the object 12 then being obtained by the formula:

D = F*W/P (equation 2).

Equation 2 is thus obtained by a triangular similarity between the ratio of the distance D to the width W of the object 12 and the ratio of the anterior distance F to the anterior width P of the object 12.

Optionally, the BSI additionally determines a speed associated with the object 12 from a plurality of determined values of the distance. The BSI determines for example a first distance D1 from the object 12, then a distance D2 associated with the same object 12 and performed after a time interval Δt, the relative speed V _R of the object 12 with respect to the vehicle 11 being obtained by the formula:

V _R = (D2 – D1) / Δt (equation 3).

The time interval Δt corresponds for example to a time interval between two executions of the method or to a predefined time step for updating the relative speed V _R of the object 12.

Of course, according to a particular design, the speed V _A of the object 12 on the traffic lane 1000 is also obtained from the relative speed V _R and a measured speed V _ego of the vehicle 11 using an embedded sensor via the formula:

V _A = V _ego + V _R (equation 4).

In particular, the speed V _A of the object 12 on the traffic lane 1000 or its relative speed V _R allows the control of an on-board ACC system of the vehicle 11 targeting an object 12 corresponding to a second vehicle, so as to maintain the longitudinal speed regulation of the vehicle 11. According to another design, the distance D from the object 12 allows the control of an LPA and/or LKA system on board the vehicle 11 targeting at least one object 12 corresponding to a marking on the ground of taxiway 1000.

When the radar signal is detected as available, the BSI performs in a fourth operation a second switching to the radar signal, the ADAS system being controlled in a fifth operation according to the radar signal, corresponding to a second control. Optionally, the second control is carried out according to the radar signal and the camera signal, that is to say that the data coming from the radar and from the camera are both used for the operation of the ADAS systems of the vehicle 11. It is understood here that the second check corresponds to a normal operation of ADAS systems and is implemented according to methods known to those skilled in the art.

Thus, the method according to the invention makes it possible to alternate between normal operation of the ADAS systems of the vehicle and degraded operation during the eventual malfunction of an on-board radar of the vehicle, making it possible to retain, at least temporarily, the operation of the ADAS systems. before a return of the availability of the on-board radar or even a resumption of control of the vehicle by the driver in the event of prolonged unavailability.

schematically illustrates a device configured to control a vehicle driving assistance system, according to a particular and non-limiting embodiment of the present invention. The device 2 corresponds for example to a device on board the vehicle 11, for example an ADAS system computer or a BSI. The device 2 is for example configured to receive data from on-board sensors of the vehicle 11 and/or other computers, and to control an ADAS system of the vehicle 11.

The device 2 is for example configured for the implementation of the operations described with regard to the and/or the steps of the process described with regard to the . Examples of such a device 2 include, but are not limited to, on-board electronic equipment such as a vehicle's on-board computer, an electronic computer such as an ECU ("Electronic Control Unit"), a telephone smart phone, tablet, laptop. The elements of device 2, individually or in combination, can be integrated in a single integrated circuit, in several integrated circuits, and/or in discrete components. The device 2 can be made in the form of electronic circuits or software (or computer) modules or else a combination of electronic circuits and software modules.

The device 2 comprises one (or more) processor(s) 20 configured to execute instructions for carrying out the steps of the method and/or for executing the instructions of the software or software embedded in the device 2. The processor 20 can include integrated memory, an input/output interface, and various circuits known to those skilled in the art. The device 2 further comprises at least one memory 21 corresponding for example to a volatile and/or non-volatile memory and/or comprises a memory storage device which can comprise volatile and/or non-volatile memory, such as EEPROM, ROM , PROM, RAM, DRAM, SRAM, flash, magnetic or optical disk.

The computer code of the onboard software or software comprising the instructions to be loaded and executed by the processor is for example stored on the memory 21.

According to various particular and non-limiting examples of embodiment, the device 2 is coupled in communication with other similar devices or systems and/or with communication devices, for example a TCU (from the English “Telematic Control Unit” or in French “Telematic Control Unit”), for example via a communication bus or through dedicated input/output ports.

According to a particular and non-limiting embodiment, the device 2 comprises a block 22 of interface elements for communicating with external devices, for example a remote server or the “cloud”, other nodes of the ad hoc network. Block 22 interface elements include one or more of the following interfaces:

- RF radio frequency interface, for example of the Wi-Fi® type (according to IEEE 802.11), for example in the 2.4 or 5 GHz frequency bands, or of the Bluetooth® type (according to IEEE 802.15.1), in the band frequency at 2.4 GHz, or of the Sigfox type using UBN radio technology (Ultra Narrow Band, in French ultra narrow band), or LoRa in the 868 MHz frequency band, LTE (from English " Long-Term Evolution” or in French “Evolution à long terme”), LTE-Advanced (or in French LTE-advanced);

- USB interface (from the English "Universal Serial Bus" or "Universal Serial Bus" in French);

- HDMI interface (from the English “High Definition Multimedia Interface”, or “Interface Multimedia Haute Definition” in French);

- LIN interface (from English “Local Interconnect Network”, or in French “Réseau interconnecté local”).

Data are for example loaded to the device 2 via the interface of block 22 using a Wi-Fi® network such as according to IEEE 802.11, an ITS G5 network based on IEEE 802.11p or a mobile network such as a 4G network (or 5G) based on the LTE (Long Term Evolution) standard defined by the 3GPP consortium, in particular an LTE-V2X network.

According to another particular and non-limiting example of embodiment, the device 2 comprises a communication interface 23 which makes it possible to establish communication with other devices (such as other computers of the on-board system) via a communication channel 24. The communication interface 23 corresponds for example to a transmitter configured to transmit and receive information and/or data via the communication channel 24. The communication interface 23 corresponds for example to a CAN-type wired network (of the 'English "Controller Area Network" or in French "Réseau de Contrôleurs"), CAN FD (from English "Controller Area Network Flexible Data-Rate" or in French "Réseau de Contrôleurs à Flow de Data Flexible"), FlexRay ( standardized by ISO 17458) or Ethernet (standardized by ISO/IEC 802-3).

According to a particular and non-limiting example of embodiment, the device 2 can supply output signals to one or more external devices, such as a display screen 25, touch-sensitive or not, one or more loudspeakers 26 and/or other peripherals 27 (projection system) respectively via output interfaces 28, 29 and 30. According to a variant, one or the other of the external devices is integrated into the device 2.

illustrates a flowchart of the different steps of a method for controlling a driver assistance system of a vehicle traveling in a road environment, for example an ADAS system of the vehicle 11, according to a particular and non-limiting example embodiment of the present invention. The method is for example implemented by a device on board the vehicle 11 or by the device 2 of the .

In a first step 31, first data representative of an availability or unavailability of a radar signal are received from at least one radar on board the vehicle 10.

In a second step 32 triggered when the radar signal is unavailable, the reception of road environment data is switched to a camera signal received from at least one camera on board the vehicle.

In a third step 33, the ADAS system is controlled according to the camera signal.

In a fourth step 34 triggered when the radar signal is available, the reception of road environment data is switched to the radar signal.

In a fifth step 35, the ADAS system is controlled according to the radar signal.

According to a variant, the variants and examples of the operations described in relation to the apply to the process steps of the .

Of course, the present invention is not limited to the exemplary embodiments described above but extends to a method for controlling a vehicle driving assistance system in a plurality of situations and/or which would include additional steps without departing from the scope of the present invention. The same would apply to a device configured for the implementation of such a method.

The present invention also relates to a vehicle, for example automobile or more generally an autonomous land motor vehicle, comprising the device 2 of the .

Claims (10)

Method for controlling a driver assistance system of a vehicle (10) traveling in a road environment (1), said method comprising the following steps:
- reception (31) of first data representative of an availability or unavailability of a radar signal, from at least one radar on board said vehicle (10);
when said radar signal is unavailable:
- first switching (32) to a camera signal received from at least one on-board camera in said vehicle;
- first control (33) of said driving assistance system according to said camera signal;
when said radar signal is available:
- second switching (34) to said radar signal;
- second control (35) of said driving assistance system according to said radar signal. A method according to claim 1, wherein said first check (33) comprises the following steps:
- reception of second data representative of said road environment (1);
- determination of representative characteristics of at least one object (12) associated with said road environment (1) as a function of said second data; And
- control of said driver assistance system according to said characteristics. A method according to claim 2, wherein said determination of characteristics comprises the following steps:
- determination of spatial coordinates associated with said at least one object (12) from a visual representation of said road environment (1) resulting from said second data;
- determination of dimensions associated with said at least one object (12) from said coordinates; And
- determination of a distance between said vehicle (11) and said at least one object (12) from said dimensions and third data representative of said at least one object (12), said third data being received from an on-board memory in said vehicle (11). A method according to claim 3, wherein said determining characteristics further comprises determining a velocity associated with said at least one object (12) from a plurality of determined values of said distance. Method according to one of Claims 1 to 4, in which the said second check (35) is carried out as a function of the said radar signal and the said camera signal. Method according to one of Claims 1 to 5, in which the said first data comprise information representative of a duration of unavailability of the said radar signal, the said first switching (32) and the said second switching (34) being carried out as a function of a result of a comparison of said duration of unavailability with a threshold value. Computer program comprising instructions for implementing the method according to any one of the preceding claims, when these instructions are executed by a processor. Computer-readable recording medium on which is recorded a computer program comprising instructions for carrying out the steps of the method according to one of Claims 1 to 6. Device (2) for controlling a vehicle driving assistance system, said device (2) comprising a memory (21) associated with at least one processor (20) configured for the implementation of the steps of the method according to any one of claims 1 to 6. Vehicle (11) comprising the device according to claim 9.