DE102010063006A1 - Comfort feature in a driver assistance system with front camera - Google Patents

Abstract

The invention relates to methods in a driver assistance system (110) with a front camera (112) in a vehicle (100), and to corresponding driver assistance systems. A method according to the invention comprises the following steps: taking an image of an area (116) located in front of the vehicle (100) with the front camera (112); Evaluating the recorded image for the presence of a stop line (108); and selective triggering, based on the evaluation, of an automatic reaction of the driver assistance system (110) for stopping precisely at the stop line (108).

Description

State of the art

The invention relates to methods in a driver assistance system with a front camera in a vehicle, as well as corresponding driver assistance systems.

A driver assistance system provides options in a vehicle to assist the driver in certain driving situations. Such additional devices are subsystems are, for example, ABS (Antilock Braking System), ESP (Electronic Stability Program), Adaptive Cruise Control (ACC), a parking assistant, etc.

Such subsystems serve driver comfort, but also increase safety. Thus, the primary goal of an ACC system is to increase comfort and relieve concentration for the driver on long freeways, while also providing a safety benefit. An ACC system determines the position and speed of a preceding vehicle based on radar or lidar and adjusts the distance to that vehicle via the ego speed, ie. H. by means of engine and brake intervention. In addition, modern systems recognize, for example, stationary obstacles such as parked vehicles or a jam end. ACC systems can also be equipped with an additional infrared camera to detect low-radar obstacles such as animals or humans. Furthermore, a follow-to-stop function is known, which slows down the vehicle to a standstill in viscous traffic or congestion and accelerates independently and / or at the instigation of the driver up to a predetermined speed again. For this purpose, additional sensors are used for close range.

It is foreseeable that future ACC systems based on a combined evaluation of radar and camera sensors will not only execute a distance control but also full braking to a standstill as well as avoiding and avoiding obstacles.

Other driver assistance subsystems also provide comfort with particular attention to relieving the driver of difficult tasks such as precise maneuvering. From the DE 10 2007 047 362 A1 a parking assistance system is known, which identifies and measures a parking space with an ultrasound-based environment detection sensor system. By means of an additional camera and downstream image processing unit, markings, restricted areas, cycle paths, driveways or the like in the area of the parking space are recorded and analyzed. In order to control the vehicle in the parking space, both the sensor data of the surroundings detection sensor system, which relate to distances to obstacles in the parking area, and the image data of the image processing unit with respect to the analyzed markings are used.

On the one hand, comfort and safety are constantly increasing due to further developments in the field of driver assistance systems; On the other hand, this trend also leads to increasingly complex systems, which are becoming increasingly expensive. This is due in particular to the fact that the additional sensor technology is used. As described above, a fully-equipped ACC system can now include a long-range radar, a short-range radar and an infrared camera, while the parking assistant at the rear of the vehicle, an ultrasonic sensor and another camera are installed. At the same time, the trend towards ever more expensive systems limits the use of additional comfort and / or safety features in the field of driver assistance.

Disclosure of the invention

According to the invention, a method is proposed in a driver assistance system of a vehicle, wherein the driver assistance system has a front camera. The method according to the invention comprises the following steps: taking an image of an area in front of the vehicle with the front camera; Evaluating the recorded image for the presence of a stop line; and selectively triggering, based on the evaluation, an automatic response of the driver assistance system for targeted stopping at the stop line. For example, the front camera may be mounted on the roof, on or behind the windshield, in association with the front bumper, with the front license plate, etc.

The method of the invention may include the further step of detecting that at least one of the following conditions is met: a vehicle speed is less than a predetermined threshold; a drive power of a vehicle engine is smaller than a predetermined threshold value; an actuation of the accelerator pedal takes place below a predetermined threshold value; an actuation of a brake pedal takes place below a predetermined threshold value; a preset gear is engaged or no gear is engaged; a turn signal is set.

The evaluation of a conditional sentence comprising one or more of the above conditions may be preceded by the step of capturing the image or an image sequence: in this case, in response to the detection that the at least one condition is met, the front camera for recording the image or the image sequence activated.

In another embodiment of the method according to the invention, the evaluation of the conditional sentence precedes the evaluation of one or more recorded images; This may be the case when the front camera z. B. is continuously active for another driver assistance subsystem. In this case, in response to the detection that the at least one condition is met, at least one of the images taken for a different reason may be used to evaluate for the existence of a stop line.

Both of the options of evaluating the conditional set either to activate the camera or to access an already captured image can be implemented in one and the same driver assistance system.

The image analysis may be performed to identify at least one of the following types of stop lines: stop lines at traffic lights, stop lines at stop signs and / or priority vehicles, parking limit lines, stop lines at threading or turning lanes. An evaluation of the detection of these and similar types of stop lines can also serve the purpose of distinguishing such types of stop lines from other possibly over one lane markings or contours, as in some countries or common practice, such as markers of pedestrian crossings , Warning markings to indicate low-traffic zones, speed bumps or similar traffic-guiding or calming structures, etc.

In certain embodiments of the method according to the invention, the image evaluation further comprises the detection of a red and / or yellow traffic light signal; this can prevent the vehicle from automatically stopping at the stop line of a green-switched traffic light, so that driver intervention becomes unnecessary. Additionally or alternatively, the image analysis may include recognizing signage, such as stop signs, priority currency signs, or other signage often associated with stop lines.

The step of triggering the automatic response of the driver assistance system may further comprise that the evaluated image or the evaluated image sequence (alternatively or additionally other images or image sequences) is used to calculate a distance to the stop line. Additionally or alternatively to the distance calculation, an automatic longitudinal guidance algorithm for guiding the vehicle precisely to stop at the stop line may also be based on the calculation of a virtual time-to-contact (TTC). Optionally, the TTC itself can be used for longitudinal guidance, so that an explicit distance determination is not required. For the automatic longitudinal guidance, it is possible to use data from further sensors, for example from wheel sensors, in order to take into account a current speed of the vehicle. A distance or TTC determination may be based on, for example, optical flow techniques. An automatic longitudinal guide may include driving a brake system and / or an engine control of the vehicle.

Advantages of the invention

According to the invention, it is proposed inter alia to use a front camera to realize a novel driver assistance comfort feature, namely the accurate stopping at stop lines, for example, traffic lights, junctions or the like. This feature relieves the driver of routine tasks and allows him to focus on the traffic. The driver assistant automatically brings the vehicle to an optimal stop position, as required, for example, in order to have the best possible overview in an intersection area. The assistant does this reproducibly and can also contribute to energy saving and noise avoidance by avoiding unnecessary braking and / or accelerating. Moreover, the feature also enhances safety by reducing the risks associated with overlooking or overriding a stop line.

The front camera may already be present in connection with another driver assistance subsystem such as, for example, an adaptive cruise control system, parking assistants, etc.

Thus, a method according to the invention can be easily retrofitted, d. H. the comfort increase associated with the invention and the gain in safety are achieved without additional components having to be installed. In one embodiment of the invention, only existing evaluation and / or control components of the driver assistance system must be equipped with appropriate software and / or firmware. In other words, existing components such as a front camera are better utilized because they can not only be used for detection of obstacles in the context of an ACC system, but also according to the invention for the evaluation of markings on the road.

Brief description of the drawings

Further aspects and advantages of the invention will now be described in more detail with reference to the accompanying figures. Hereby shows:

1 a vehicle equipped with a driver assistance system according to the invention in an exemplary driving situation;

2 a schematic representation of functional components of the driver assistance system 1 ; and

3 in the form of a flowchart, an operation of the driver assistance system 2 ,

Embodiments of the invention

1 shows a schematic overview of a vehicle 100 , which is a junction area 102 on a roadway 104 approaches. In front of the junction 102 there is a traffic light 106 with a mark on the roadway 104 applied stop line 108 ,

The vehicle 100 has a driver assistance system 110 which is a front camera 112 and at least one processing unit embodied as an ECU ("Electronic Control Unit") 114 includes. The driver assistance system according to the invention 110 recognizes when approaching the junction area 102 the stop line 108 and a red signal at the traffic light 106 and then leads the vehicle 100 accurately in an optimal stop position before the stop line 108 , This scenario is described in detail below.

In 2 are in schematic form functional components of the driver assistance system 110 indicated. At the camera 112 it can be an optical and / or infrared camera, as used for an ACC system, a parking assistant or another driver assistance subsystem. The ECU 114 includes a control component 202 to control the camera 112 , an image evaluation component 204 and a persistence assistance component 206 , A way of working in 2 shown components is based on the flowchart 300 in 3 described.

Related to the in 1 sketched situation, the components shown work together to the vehicle 100 exactly in front of the stop line 108 to stop ( 302 ). In step 304 takes the camera 112 an image (or image sequence) of one in front of the vehicle 100 area (in 1 is a field of vision 116 the camera 112 indicated). The engine 202 controls the camera 112 accordingly and takes the image representing data from the camera 112 opposite.

In the example discussed here, it is especially assumed that the camera 112 is continuously operated to send data to an ACC system 208 to deliver what a distance of the vehicle 100 to an anticipatory moving vehicle 118 regulates. In the course of this the control component delivers 202 continuously image data of the camera 112 to the ACC subsystem 208 , An inventive comfort feature "automatic stop stop lines" is activated, therefore checks the control component 202 regularly additionally by evaluating an image or a sequence of images, the or from the to the ACC system 208 supplied picture stream is picked out, whether a stop line in the field of vision 116 the camera 112 shows up.

The extraction of an image or sequence of images from the image stream is in response to the evaluation of a set of conditions contained in one of the control components 202 allocated memory area 210 are stored. According to these conditions, it is decided whether a picture / a picture sequence is picked out and an evaluation of the picture picked out. Image sequence is performed on the presence of a stop line.

The conditions may include, for example, a vehicle speed lower than a predetermined speed, for example, 80 kilometers per hour (km / h). This condition can be based on the data, for example, a wheel sensor 212 from the engine 202 be checked. If the vehicle moves faster than this predetermined maximum speed, it is assumed that a stop line does not occur because the vehicle is approximately on a motorway or otherwise intersection or traffic-free route (also an automatic stop above a certain speed u Not possible without danger).

It can also be checked whether the driver is actively pressing the accelerator pedal. If this is the case, this is taken as an indication that an automatic stop is not desired. The driver assistance system may generally be configured such that by an active actuation of the accelerator pedal by the driver (i.e., an operation that is above a predefined force value), an already initiated automatic stop operation is aborted. The driver can therefore at any time take over control of the vehicle itself and can, for example, perform the stopping process itself.

The above set of conditions may also contain the condition that the Driver currently the brake pedal is not pressed. The same applies mutatis mutandis to the case of the operation of the accelerator pedal. If the brake pedal is pressed, so no image from the to the ACC system 208 taken out guided image stream. Likewise, an already initiated automatic stop process can be aborted. Overall, the method according to the invention can thus be overridden by a single tap of accelerator pedal or brake for the (closest) stop line located in the detection range of the camera until it has been passed over.

A check of the conditional sentence may, for example, while driving the vehicle 100 at regular intervals. Possibly. In this case, an image removal frequency is to be selected as a function of the instantaneous vehicle speed such that one in the detection range 116 the camera 112 appearing stop line can be reliably detected. Corresponding evaluation intervals could thus z. Example, one second or fractions of seconds, for example, 0.5 or 0.3 seconds.

If all conditions are fulfilled, the control component takes out 202 out of the camera 112 the ACC subsystem 208 fed image stream (image sequence) and passes this to the evaluation component 204 further. This evaluates in step 306 the captured image for the presence of a stop line.

The of the component 204 Image evaluation performed is based on an allocated memory area 214 stored algorithms or templates for different types of stop lines, like those in the camera 112 taken pictures. The templates include patterns for expansion, contour and shape of stop lines in the field of view of the camera. For example, templates for stop lines can be stored at traffic lights, stop signs, at threading or turning lanes, but also for parking space delineation lines. Furthermore, templates for pedestrian crossings, for example, traffic signs marked on the roadway, such as speed limits and similar markings that can be overridden, are stored by the evaluation component 204 must also be recognized and distinguished from stop lines.

In addition, the evaluation unit 204 be adapted to detect traffic lights, in the field of view of the camera 112 appear. Shows the traffic light 106 in the scenario in 1 For example, red or yellow, the correspondingly recognized traffic light signal can be used to trigger an automatically guided stop, while a detected green traffic light signal causes the stop line 108 is ignored, ie no automatic stop is triggered.

Furthermore, the evaluation unit 204 also be designed for the detection of traffic signs such as stop or Vorfahrtgewährungsschildern, with corresponding templates for such signs also in the memory area 214 can be stored.

The evaluation component 204 returns the recognition result to the engine 202 , In step 308 a decision is made based on the recognition result as to whether an automatic stop is to be triggered (branch load 310 ) or not (branch branch 312 ). If no stop line has been detected or a stop line to be crossed has been detected (for example because of an associated green traffic light signal), the branch branch will be used 312 the procedure repeats without action cyclically, ie after the expiry of the period of time discussed above, the step again 304 carried out.

If it is decided that an automatic stop process is to be triggered, is according to Ast 310 next the step 314 carried out. Here triggers the engine 202 the arrest assistant 206 , This component calculates in what way the vehicle 100 is to guide it so that it is accurate to the stop line 108 comes to a stop. For a corresponding algorithm, for example, a determination (estimate) of the current distance of the vehicle 100 from the stop line 108 to be required. Besides or instead of a distance, a TTC can also be the basis of a longitudinal guidance algorithm. So, an approach to the stop line 108 also be calculated and performed so that a TTC is kept constant.

The distance from the stop line 108 and / or the TTC can be estimated, for example, based on optical flow methods. This will be an apparent increase in the stop line 108 in the field of vision of the camera 112 evaluated in temporal successive images, for this purpose by the control component 202 be transmitted. This image sequence may include the image or images that are in step 306 were evaluated for the existence of a stop line. For the calculation, a current speed of the vehicle 100 needed; this is the responsibility of the control component 202 Data of the wheel or speed sensor 212 to the component 206 further.

Based on the calculation performed, the component generates 206 finally corresponding control commands and controls with these a braking system 218 and optionally one motor control 220 of the vehicle 100 at. The procedure ends in step 316 with that the vehicle 100 at the stop line 108 comes to a stop.

The invention is not limited to the embodiments described herein and the aspects highlighted therein; Rather, within the scope given by the appended claims a variety of modifications are possible, which are within the scope of expert action.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007047362 A1 [0005]

Claims (10)

Method in a driver assistance system of a vehicle, wherein the driver assistance system ( 110 ) a front camera ( 112 ), with the following steps: - recording ( 304 ) of an image of an in front of the vehicle ( 100 ) area ( 116 ) with the front camera ( 112 ); - evaluate ( 306 ) of the recorded image for the presence of a stop line ( 108 ); and - selective ( 308 ) Trigger ( 310 . 314 ), based on the evaluation, of an automatic response of the driver assistance system ( 110 ) for a precise stop at the stop line ( 108 ). The method of claim 1, comprising the further step of detecting that at least one of the following conditions is met: a vehicle speed is less than a predetermined threshold; a drive power of a vehicle engine is smaller than a predetermined threshold value; an actuation of an accelerator pedal takes place below a predetermined threshold value; an actuation of a brake pedal takes place below a predetermined threshold value; a predetermined gear or no gear is engaged; a turn signal is set. The method of claim 2, wherein in response to detecting that the at least one condition is met, the front camera is activated to capture the image. Method according to claim 2, wherein the front camera ( 112 ) is continuously active and in response to the detection that the at least one condition is met, at least one of the recorded images is used and an evaluation for the existence of a stop line ( 108 ) is performed based on the image used. Method according to one of the preceding claims, wherein the evaluation is carried out to detect at least one of the following types of stop lines: stop lines ( 108 ) at traffic lights, stop lines at stop signs and / or priority vehicles, parking limit lines, stop lines at threading or turning lanes. Method according to one of the preceding claims, wherein the evaluation further comprises the detection of a red and / or yellow traffic light signal. Method according to one of the preceding claims, wherein the evaluation further comprises the detection of a stop sign. Method according to one of the preceding claims, wherein the triggering of the automatic response of the driver assistance system comprises, based on the image or an image sequence comprising the evaluated image, an automatic longitudinal guidance to the stop line (FIG. 108 ) to calculate. Computer program for carrying out the method according to one of the preceding claims, when the computer program is executed on a programmable computer device. Driver assistance system ( 110 ) in a vehicle ( 100 ), with the following components: - a front camera ( 112 ) for taking an image of an area in front of the vehicle ( 116 ); - one component ( 204 ) for evaluating the recorded image for the presence of a stop line ( 108 ); and a component ( 202 ) for selectively triggering, based on the evaluation, an automatic response of the driver assistance system ( 110 ) for a precise stop at the stop line ( 108 ).

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