FR2968623A1 - DRIVING ASSISTANCE SYSTEM METHOD - Google Patents

Abstract

A driving assistance system method (110) comprising a front camera (112), the method comprises the following steps: - shooting an image of the area (116) in front of the vehicle (100) with the front camera (112), - exploiting the image taken to detect the presence of a stop line (108), and - selectively trigger according to the operation, an automatic reaction of the driver assistance system (110) for a precise stop in front of the stop line (108).

Description

FIELD OF THE INVENTION The present invention relates to a method of a vehicle driving assistance system, comprising a front camera.

State of the art In a vehicle a driving assistance system provides additional facilities to assist the driver in certain driving situations. Such additional facilities are subsystems, for example the ABS anti-lock system, the ESP electronic stabilization program, the interval regulator (ACC system, adaptive cruise control), the parking or parking maneuvering assistance system. storage, etc ... Such subsystems promote driver comfort and increase safety. While the main purpose of an ACC system is to improve comfort and reduce driver concentration on long-haul motorways, this system also improves safety. An ACC system determines the position and speed of the preceding vehicle based on information from the radar or lidar to regulate the distance from the vehicle by adjusting the own speed, ie with the engine and brakes; the current systems also detect, for example, fixed obstacles, such as parked vehicles or obstacles, traffic jams, such as ACC subsystems which may also be equipped with an additional infrared camera. Such a camera makes it possible to avoid with a weak radar reflection, or to detect animals and pedestrians. In addition, there is known a function of continuation until the stop according to which the vehicle is braked if necessary to the stop if the circulation is very little fluid or if there are plugs; the system and the vehicle are accelerated again when the driver disengages, to move from a preset speed to the set speed that uses more sensors for the near area. It is expected that future ACC systems, based on combined radar and camera operation, will not only provide distance regulation, but also complete braking to a standstill as well as avoidance and automatic bypass of obstacles. There are also other driver assistance subsystems to improve comfort and especially to free the driver from difficult operations such as very precise maneuvers. DE 10 2007 047 362 A1 discloses a storage location assisting system in a parking space of identifying a parking space with ultrasonic environmental sensing sensors and measuring that parking space. An additional camera and an image processing unit make it possible to enter and analyze markings, forbidden surfaces, cyclist lanes, entrances or the like in the parking space. To guide the vehicle into the parking space, the data of the environmental detection sensors measuring the distances to the obstacles in the parking space and also the image data of the unit are used. of image processing for the analysis of markings. On the one hand, comfort and safety increase thanks to the development in the field of driver assistance systems and on the other hand, this trend is reflected in increasingly complex and increasingly expensive systems. This stems in particular from the fact that it is necessary to use additional sensors. As described above, a fully developed ACC system includes a long-range radar, a short-range radar and an infrared camera, while for parking assistance systems, ultrasonic sensors and another camera are required. rear of the vehicle. This trend toward increasingly expensive systems, however, limits the use of other safety features and / or comfort in the field of driving assistance. DESCRIPTION AND ADVANTAGES OF THE INVENTION The subject of the present invention is a vehicle driving assistance system method according to which the driving assistance system comprises a front camera, this method being characterized by the following steps:

3 - shooting an image of the area in front of the vehicle with the front camera, - exploiting the image taken to detect the presence of a stop line, and - selectively trigger depending on the operation, an automatic reaction of the driver assistance system for a precise stop in front of the stop line. The front camera is for example installed on the roof, on the windshield or behind the windshield or in combination with the front bumper, the front registration plate or others.

The method is characterized in that it also comprises the input step if at least one of the following conditions is fulfilled: the vehicle speed is below a predefined threshold; the driving power supplied by the engine of the vehicle; vehicle is below a predefined threshold, - the accelerator pedal operation is below a predefined threshold, - the brake pedal action is below a predefined threshold, - a gear ratio given or no gear ratio is passed, - the flashing is set. The operation of a set of conditions comprising one or more of the conditions set out above is preceded by the step of taking a view or a sequence of images: in this case, in response to input, if at least one of the conditions is fulfilled, the front camera will be activated to take an image or sequence of images. According to another development of the method of the invention, the exploitation of the set of conditions is preceded by the exploitation of one or more images taken; this may be the case if the front camera is, for example, continuously activated for another driving assistance subsystem. In this case, in response to the input, if at least one of the conditions is fulfilled, at least one of the images taken elsewhere can be used to exploit it and detect the presence of a stop line.

The two options namely, exploit the set of conditions to activate the camera or access an image taken elsewhere, can be implemented in one and the same driver assistance system.

The image can be used to detect at least one of the following stop line types: stop line, stop line at a traffic light, stop line at a stop sign and / or sign of priority, line delimiting a parking space, stop line for nesting in a queue or for branching. One can exploit to detect either type of stop line to distinguish such types of stop line from other markings or contours also crossing a traffic lane, as is the case in some countries or in general such as pedestrian crossing markings, warning markings to indicate slow traffic areas, brake bars or other guidance or deceleration structures. According to a development of the method of the invention, the exploitation of the image further consists in detecting a red and / or yellow light; this prevents the vehicle from automatically stopping at the stop line if the light has turned green, to avoid intervention by the driver. In addition or alternatively, the exploitation of the image may include the detection of traffic signs, such as for example stops, priority panels or other panels that are frequently associated with lines of stops. The step of triggering the automatic reaction of the driver assistance system may further consist in using the exploited image or the sequence of exploited images (alternatively or in addition to other images or other 'images' to calculate the distance from the stop line. In addition or alternatively to the calculation of the distance, an automatic longitudinal guidance algorithm can be applied to drive the vehicle so that it stops accurately on the stop line by applying a sort of virtual calculation TTC (system says "time to contact"). If necessary, the TTC application can itself be used for longitudinal guidance so that it does not need to explicitly determine the distance. For automatic longitudinal guidance, data from other sensors, such as wheel sensors, can be used, taking into account the instantaneous speed of the vehicle. The determination of the TTC distance or application may be based on the optical flow method; the automatic longitudinal guidance may comprise the control of the brake system and / or the control of the vehicle engine. Advantages of the invention The invention proposes, among other things, the use of a front camera to develop a new type of driver assistance comfort characteristics, namely the precise stopping at a stop line such as at a traffic light. signaling system, a junction of traffic lanes or similar situation. This feature prevents the driver from having to perform routine operations and allows him to concentrate on the traffic. The driver assistance system automatically puts the vehicle in an optimal stopping position such as is necessary for example to have the best visibility at an intersection. The driving assistant does this in a reproducible way and also helps to save energy and reduce noise by avoiding unnecessary braking or acceleration. In addition, this feature enhances safety by reducing the risk of inadvertently passing a stop line. The front camera may be the one that already exists for another driver assistance subsystem such as, for example, automatic interval control between vehicles, parking assistance system, etc. The process according to the invention can be installed simply a posteriori, that is to say, to improve comfort and safety without having to install additional components. According to one embodiment of the invention, it is sufficient to equip the control and operating components of the driving assistance system with the appropriate program and / or circuits. In other words, the existing components such as the front camera, will be better used because these components will no longer be used only in the context of the ACC system for the detection of obstacles, but they will serve according to the invention, the exploitation pavement markings. Drawings The present invention will be described hereinafter in more detail using a driver assistance method and a driver assistance system shown in the accompanying drawings in which: - Figure 1 shows schematically a vehicle equipped with a driver assistance system according to the invention in an exemplary driving situation, - Figure 2 is a schematic representation of the functional components of the driving assistance system according to Figure 1, and - the FIG. 3 is a flow chart for implementing the driving assistance system of FIG. 2.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 is a schematic overall view of a vehicle 100 which approaches a junction 102 on a roadway 104. Upstream of the junction zone 102, there is a red light 106 with as marking, a stop line 108 on the roadway 104.

The vehicle 100 is equipped with a driving assistance system 110 comprising a front camera 112 and at least one processing unit 114 in the form of an ECU electronic control unit. The driver assistance system 110 according to the invention detects the stop line 108 when approaching the junction 102 and the red light signal 106 to drive the vehicle 100 precisely in an optimal stopping position in front of the vehicle. stop line 108. This scenario will be described in detail below. FIG. 2 schematically shows the functional components of the driver assistance system 110. The camera 112 is for example an optical and / or infrared camera such as that used in the ACC systems, parking assistance systems (help parking) or other driver assistance subsystems. The ECU 114 includes a control component 202 for controlling the camera 112, an image processing component 204 and a stop assist component 206. The operation of the components of FIG. 2 will be explained in FIG. using the flow chart 300 of FIG. 3. In the case of the situation sketched in FIG. 1, the components presented cooperate to stop (302) precisely the vehicle 100 in front of the stop line 108. (304), the camera 112 takes an image (a sequence of images) of the area upstream of the vehicle 100 (the field of view 116 of the camera 112 is indicated in FIG. 1). The control component 202 thus acts on the camera 112 and takes the data representing the image of the camera 112.

In the example presented, it is notably assumed that the camera 112 operates continuously to supply the data to an ACC 208 system which regulates the distance between the vehicle 100 and the vehicle 118 which precedes it. During this operation, the control component 202 continuously delivers image data from the camera 112 to the ACC subsystem 208. A comfort feature according to the invention, namely "automatic stop at the stop line ", is activated so that the control component 202 regularly checks additionally by the exploitation of an image or a sequence of images that the image stream or images supplied by the ACC 208 system, are filtered for see the appearance of a stop line in the field of view 116 of the camera 112. The extraction of an image or a sequence of images from the image stream is in response to the exploitation a set of conditions stored in the memory area 210 associated with the control component 202. Under these conditions, it is decided to extract an image / sequence of images and to use the image or sequence extracted images to detect the presence of a stop line. As conditions, it is for example the fact that the speed of the vehicle is less than a predefined speed, for example 80 km / h. This condition is verified by means of the data, for example that of a wheel sensor 212 by the control component 202. If the vehicle moves faster than the predefined maximum speed, it is assumed that there will be no no stop line because the vehicle runs on a motorway or other type of road, without intersection or red light (an automatic stop over a certain speed is not possible among others without creating risks). It is further verified that the driver actively actuates the accelerator pedal. If this is the case, it means that one does not wish to stop automatically. The driver assistance system can be configured generally so that active actuation of the accelerator pedal by the driver (ie actuation exceeding a predefined force), stops a stopping phase automatic that would have already been launched. The driver 10 can, at any time, regain control of the vehicle, itself, and for example perform itself a stopping phase. The set of conditions presented above, may also contain the condition that the driver does not momentarily actuate the brake pedal. For this purpose, the same elements will be correspondingly as for the case of actuation of the accelerator pedal. If the brake pedal is actuated, no image will be extracted from the image flow supplied to the ACC system 208. Similarly, it is possible to stop an automatic stopping phase previously launched. Overall, the method according to the invention can, if the accelerator pedal or the brake pedal have been touched once, turn off the (nearest) stop line in the entry zone. from the camera to the passage of this line. For example, it is possible to check the set of conditions during the movement of the vehicle 100 in regular time intervals. If necessary, a shooting frequency is selected according to the instantaneous speed of the vehicle to detect with certainty a stop line which would appear in the entry range 118 of the camera 112. Corresponding operating intervals, can be for example a second or a fraction of a second, for example 0.5 or 0.3 seconds. If all conditions are met, the control component 202 extracts from the image stream of the camera 112 supplied to the ACC 208 subsystem (image sequence) and transfers them to the operating component 204. image taken in step 306 to detect the presence of a stop line.

The image exploitation (s) performed by the component 204, is based on output algorithms or templates stored in the memory area 214 for different types of stop lines such as those appearing in the images taken by the device. 112. The templates or patterns are for example a pattern of extension of contour and shape of the lines of stops in the field of view of the camera. For example, it is possible to record templates or patterns of stop lines at red lights, stop signs, entanglement or deflection traces, but also lines delimiting parking places. Patterns or examples of pedestrian crossings, signs of traffic patterned on the roadway, such as, for example, speed limits or other transferred markings, similar, which are also recognized by operating components 204 and should be considered, should also be considered. different lines of stops. In addition, the operating unit 204 is designed to recognize red light signals appearing in the field of view of the camera 112. If the dipped beam 106 of the scenario of FIG. 1 is for example red or yellow , the recognized fire signal 20 will be used to trigger an automatic stop phase while the detected signal of a green light ignores the stop line 108, that is to say does not trigger a stop phase automatic. The operating unit 204 may also be used to detect traffic signs such as stop or priority signs and patterns or patterns corresponding to such signs also recorded in the memory area 214. The operating component 204 provides the result of the feedback detection to the control component 202. In the step 308, depending on the detection result, it is decided whether an automatic stop operation is to be triggered (bypass path 310) or not ( bypass road 312). If no stop line has been detected or if a stop line to be passed has been detected (for example because the fire was green), according to branch 312, the operation is repeated cyclically without produce action, that is, at the end of the period examined, step 304 is repeated.

If it is decided to trigger the automatic stop phase, then according to the branch 310, the next step 314 is executed. The control component 202 triggers the stopping assistant 206. This component calculates the manner of driving the vehicle 100 so that it stops precisely in front of the stopping line 108. An appropriate algorithm, for example can determine (evaluate ) the instantaneous distance between the vehicle 100 and the stop line 108. Besides or instead of the distance, one can also use a base TTC, a longitudinal guidance algorithm. Thus, the reconciliation of the stop line 108 will also be calculated and executed to have a constant TTC base. The distance relative to the stop line 108 and / or the TTC base can be evaluated for example by an optical flow method. For this purpose, the apparent enlargement of the stop line 108 is used in the field of view of the camera 112 as part of the images which follow each other in time and are transmitted for this purpose by the control components 202. This image sequence may include the one or more images used in step 306 to detect the presence of a stop line. For calculation, one may need the instantaneous speed of the vehicle 100; for this, the control component 202 transmits the data of the wheel or speed sensor 212 to the component 206. Depending on the calculation made, the component 206 finally generates control commands and thus manages the brake system 218 and, as the case may be, the engine control 220 of the vehicle 100. The method ends with the step 316 in that the vehicle 100 stops in front of the stop line 108. The invention is not limited to the examples described and allows multiple variants.30 NOMENCLATURE

100 vehicle 102 junction / intersection / junction 104 roadway 106 traffic light 108 stop line 110 driver assistance system 112 front camera 114 processing unit ECU 116 camera field of view 202 control component 204 operating component image 206 component of shutdown assistant 208 system ACC 210 memory area 212 radar sensor 300 flow chart 302-316 steps of flow chart process 30020

Claims (1)

CLAIMS 1 °) A method of a vehicle driving assistance system according to which, the driver assistance system (110) comprises a front camera (112), characterized by the following steps: - shooting (304) of an image of the area (116) in front of the vehicle (100) with the front camera (112), - exploiting (306) the image taken to detect the presence of a stop line (108), and - triggering (310, 314) selectively (308) depending on the operation, an automatic response of the driver assistance system (110) for a precise stop in front of the stop line (108). Method according to claim 1, characterized in that it furthermore comprises the following input step if at least one of the following conditions is fulfilled: the vehicle speed is below a predefined threshold; motor power supplied by the vehicle engine is less than a predefined threshold, - the accelerator pedal action is below a predefined threshold, - the brake pedal action is below a threshold predefined, - a given gear ratio or no gear ratio has passed, - the flashing light is on. Method according to claim 2, characterized in that in response to the input and if at least one of the conditions is fulfilled, the front camera is activated to take the image. Method according to Claim 2, characterized in that the front camera (112) is continuously activated and in response to the input, if at least one condition is fulfilled, at least one of the images taken is used and the operation of the presence of a stop line (108) is carried out on the basis of the image taken. Method according to claim 1, characterized in that one exploits to detect at least one of the following types of stop lines: - lines of stops (108) at the traffic lights, lines of stops at the stop signs and / or priority signs, the parking lot limitation lines, the stop lines for the entry or diversion lanes. 6. The method as claimed in claim 1, characterized in that the operation also comprises detecting a red and / or yellow traffic light signal. 7 °) Method according to claim 1, characterized in that the operation further comprises the detection of a stop sign. Method according to Claim 1, characterized in that the triggering of the automatic reaction comprises the driving assistance system using the image or a sequence of images detected by the image exploited for calculate the automatic longitudinal guidance to the stop line (108). 9 °) computer program for implementing the method according to one of claims 1 to 8 when the computer program product is executed in a computer programmed installation.35 14 10 °) Assistance system of pipe (110) fitted to a vehicle (100), characterized in that it comprises: - a front camera (112) for taking the image of a zone (116) situated upstream of the vehicle, a component (204) for exploiting an image taken to detect the existence of a stop line (108), and a component (202) for selectively triggering an automatic response of the driver assistance system (110) according to the operation for stop precisely on the stop line (108) .10