WO2019154745A1

WO2019154745A1 - Method for sensing an object in a surrounding region of a motor vehicle comprising estimating the height of the object on the basis of echo portions of a received signal, processor unit, ultrasonic sensor and driver assistance system

Info

Publication number: WO2019154745A1
Application number: PCT/EP2019/052589
Authority: WO
Inventors: Thomas Jung; Wolfgang Hamm
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2018-02-08
Filing date: 2019-02-04
Publication date: 2019-08-15
Also published as: DE102018102786A1

Abstract

The invention relates to a method for sensing an object (8) in a surrounding region (9) of a motor vehicle (1), in which method: an ultrasonic sensor (4) is actuated to emit an ultrasonic signal; a received signal (10) is determined, which describes a time curve of the ultrasonic signal reflected in the surrounding region (9); the received signal (10) is compared with a threshold curve (17) and if a first echo portion (18) of the received signal (10) exceeds the threshold curve (17), it is assumed that this first echo portion (18) describes an echo of the ultrasonic signal reflected by the object (8), wherein if the first echo portion (18) exceeds the threshold curve (17), the received signal (10) is checked independently of the threshold curve (17) to see if said signal has, in at least one predefined window (20a, 20b), a second echo portion (19) which describes at least one signal peak of the received signal (10), and the height of the object is estimated on the basis of the first echo portion (18) and/or the second echo portion (19).

Description

Method for detecting an object in a surrounding area of a motor vehicle with estimation of the height of the object based on echo components of a received signal,

Computing device, ultrasonic sensor and driver assistance system

The present invention relates to a method for detecting an object in an environmental region of a motor vehicle, in which an ultrasonic sensor for

Emission of an ultrasonic signal is controlled, a received signal is determined which a temporal course of the reflected in the surrounding area

Ultrasonic signal describes the received signal is compared with a threshold curve and if a first echo portion of the received signal, the threshold curve

is exceeded, it is assumed that this first echo component describes an echo of the ultrasound signal reflected by the object. Moreover, the present invention relates to a computing device for an ultrasonic sensor, an ultrasonic sensor and a driver assistance system. Furthermore, the present invention relates to a

Computer program product and a computer readable medium.

The interest here is directed to ultrasonic sensors for motor vehicles.

Such ultrasonic sensors may be part of a driver assistance system, for example, which serves to assist a driver when driving the motor vehicle. In particular, ultrasonic sensors are used to determine a distance to an object or to determine a relative position between the motor vehicle and the object. For this purpose, an ultrasound signal is emitted with the ultrasound sensor and the ultrasound signal reflected by the object is received again. Based on the transit time between the emission of the ultrasonic signal and the

Receiving the reflected from the object ultrasonic signal can then under

Considering the speed of sound the distance to the object can be determined.

Ultrasound sensors can not measure the height of an object directly. However, height is an important factor in deciding whether an object or obstacle can be overrun or not. Depending on the height of the object, the echo information is processed in different ways, for example by means of a driver assistance system. For example, in a high object, the motor vehicle is braked in front of the object, whereby an object classified as low is run over. Currently, this classification is in a central control unit of the Motor vehicle or the driver assistance system based on sensor signals, which are provided with the ultrasonic sensors made.

In order to estimate the height of an object using an ultrasonic sensor, various methods are known from the prior art. For example, it can be checked whether in addition to a first echo component or first echo of the

Ultrasonic signal also a second echo component or a second echo is present. In this case, two echo information can be evaluated. On the one hand, it can be checked whether a second echo component is present directly after the first echo component. On the other hand, it can be checked whether a second echo component with twice the duration of the first echo component is present.

For this purpose, DE 10 2005 044 050 A1 describes a method for parking space determination for motor vehicles. In this case, by means of a pulse CV method using an ultrasonic sensor with a transmitting receiving device, a removal of objects located laterally from the motor vehicle is carried out. It is envisaged that based on the detection of two echo signals as a double echo whose time interval is less than a predetermined maximum distance, an assessment is made in terms of the height of the object.

In addition, DE 10 2007 035 219 A1 describes

Object classification method for classifying an object. In this case, a transmission signal is emitted by the vehicle in the direction of a track boundary and the reflected received signal is received. Furthermore, local maxima of the received signal are counted within a time interval. Furthermore, a

Object classification signal generated, which depends on the number of local maxima of the received signal. The object classification signal may assume a first state if the received signal has no or exactly one local maximum. Furthermore, the object classification signal may assume a second state if the received signal has two or more local maxima within the temporal segment. Thus, a classification of the object in two heights (traversable and not traversable) can be realized.

With the respective ultrasonic sensors, a reception signal is provided which describes the ultrasonic signal reflected by the object. This received signal is usually compared with a threshold curve. An echo part of the

Receive signal which exceeds this threshold curve is then considered by the Object assuming assumed. If a second echo portion, which briefly follows the first echo portion, is too high or too low, this information is not transmitted to the controller. The detection of the second echo component also depends on the set threshold curve. This can make it a wrong one

Estimation of the object height come.

It is an object of the present invention to provide a solution as to how the height of an object can be more reliably estimated using an ultrasonic sensor.

This object is achieved by a method by a

Computing device, by a driver assistance system, by a

Computer program product as well as by a computer readable medium with the

Characteristics solved according to the respective independent claims. advantageous

Further developments of the present invention are the subject of the dependent

Claims.

According to one embodiment of a method for detecting an object in an environmental region of a motor vehicle, an ultrasonic sensor for emitting an ultrasonic signal is preferably activated. In addition, in particular, a received signal is determined, which preferably a temporal course of the in the

Surrounding area reflected ultrasonic signal describes. Furthermore, the received signal is preferably compared with a threshold curve, and if a first echo component of the received signal exceeds the threshold curve, it is preferably assumed that this first echo component describes an echo of the ultrasound signal reflected by the object. In addition, it is preferably provided that, if the first echo component exceeds the threshold curve, it is preferably checked independently of the threshold curve whether the received signal is present in at least one of the thresholds

predetermined window has a further echo component, which in particular describes a signal peak of the received signal. Preferably, a height of the object is estimated on the basis of the first echo component and / or the second echo component.

An inventive method is used to detect an object in one

Surrounding area of a motor vehicle. This is an ultrasonic sensor for

Emission of an ultrasonic signal driven. In addition, a received signal is determined, which describes a time profile of the reflected ultrasonic signal in the surrounding area. This received signal is compared with a threshold curve and if a first echo portion of the received signal, the threshold curve is exceeded, it is assumed that this first echo component describes an echo of the ultrasound signal reflected by the object. It is provided that, if the first echo portion exceeds the threshold curve, regardless of the

Threshold curve is checked, whether the received signal in at least one

predetermined window has a second echo portion, which describes a signal peak of the received signal. In addition, the height of the object is estimated on the basis of the first echo component and / or the second echo component.

In the present case, the object in the surrounding area of the motor vehicle is to be characterized by means of the ultrasonic sensor. In particular, the height of the object is to be estimated by means of the measurement of the ultrasonic sensor. Thus, for example, it can be determined whether the object is a high object or a low object. It low object can describe such an object, which can be run over by the motor vehicle, for example, without a

Damage to the vehicle threatens. When a high object usually threatens damage to the motor vehicle. The height of the object is thereby preferably determined along the vertical direction of the motor vehicle. The procedure can

be performed for example with a computing device or a sensor electronics of the ultrasonic sensor. To estimate the height of the object, an ultrasound signal is emitted by the ultrasound sensor and the ultrasound signal reflected by the object is received again. To emit the ultrasonic signal, a membrane of the ultrasonic sensor using a corresponding

Transducer element, such as a piezoelectric element, are excited to mechanical vibrations. For this purpose, for example, an excitation signal can be transmitted to the transducer element by means of the computing device. The ultrasonic signal reflected from the object again strikes the diaphragm, causing the transducer element to vibrate. By means of the transducer element, a sensor signal or a received signal can then be provided which describes the oscillation of the diaphragm as a function of time. In particular, the received signal can describe a time profile of the amplitudes of the sensor signal or of the ultrasonic signal reflected by the object.

For example, the received signal can describe an envelope of the sensor signal. The received signal or the amplitude characteristic of the received signal is then compared with a predetermined threshold curve. It is checked whether the received signal exceeds the threshold curve. The first echo part of the

Received signal, an echo of the reflected ultrasound signal from the object assigned. Thus, upon detection of the first echo portion, it can be assumed that the object exists in the surrounding area.

According to an essential aspect of the present invention, it is provided that, if the first echo component exceeds the threshold curve, it is checked independently of the threshold curve whether the echo component has the second echo component in at least one predetermined window. This second echo component describes at least one signal peak of the received signal. After the first echo portion in the

Received signal is detected, it is assumed that the emitted ultrasonic signal has been reflected by the object. It is then checked whether the received signal has the second echo component. For this purpose, the

Reception signal but especially not compared with the threshold curve. To determine the second echo component, it is checked whether the received signal has at least one signal peak or one local maximum. If the received signal describes a profile of the amplitudes of the oscillation of the membrane of the ultrasonic sensor when receiving the ultrasonic signal, it can be checked whether the

Receive signal has a signal peak or a maximum. It is further provided that the second echo component is searched for in the at least one predetermined window. This at least one window describes a region in which the second echo component or the second echo of the ultrasound signal usually occur. In this way, the evaluation of the received signal can be made directly to the ultrasonic sensor and independently of the threshold curve. This increases the robustness of the height detection of the object.

The object is preferably assumed to be high if the received signal has the second echo component. The second echo portion can, for example, of a

Multiple reflection of the ultrasonic signal originate. Here, the ultrasonic signal in addition to the object on a floor or at a

Road surface reflected. This is followed by the second echo of the ultrasound signal, which is assigned to the second echo component, usually shortly after the first echo, which is assigned to the first echo component. The second echo component may also be due to the fact that the ultrasound signal, which is reflected at the object, is again reflected at the ultrasound sensor or the motor vehicle, returns to the object and is reflected by the latter back to the ultrasound sensor. If the second echo component is detected in the received signal, it can be assumed that the object is a high object. This information can be determined by means of the computing device of the ultrasonic sensor and to the central control unit of the motor vehicle or the

Driver assistance system are transmitted. That way that can

Driver assistance system of the motor vehicle can be operated reliably and safely.

In a further embodiment, the at least one predetermined window is assigned to a time range and / or an amplitude range of the received signal, the time range and / or the amplitude range being dependent on the first

Echo component can be determined. The at least one window describes the area of the received signal, in which portions of the second echo are usually present. It is also possible to define a plurality of predetermined windows in which it is checked whether the second echo component is present. In doing so, the window will be relative to the

Time range defined. Alternatively or additionally, the at least one window can also be determined with respect to the amplitude of the received signal. That's it

provided that the at least one predetermined window is determined in dependence on the first echo or the first echo component. The at least one window can then be determined in relation to the first echo component. This enables an efficient evaluation of the received signal.

In this case, provision is made in particular for the time range to have a predetermined time interval with respect to the first echo portion, wherein the time interval is predetermined as a function of a distance to the object and / or an installed position of the ultrasound sensor. The transit time difference between the first echo portion and the second echo portion is dependent on the distance and / or the installation position. The distance between the ultrasound sensor and the object can be determined on the basis of the first echo component or a transit time assigned to the first echo component. Depending on this distance, the time range can then be determined. Alternatively or additionally, the time range of the installation position, for example, a mounting height, the ultrasonic sensor can be determined on the motor vehicle. In particular, it is provided that the predetermined time interval is between 30 ps and 70 ps, in particular 50 ps. If the ultrasound signal is additionally reflected at the ground or the road surface, the second echo component follows almost directly to the first echo component. Here, experiments and / or simulations have shown that this second echo component is usually received after a period of 50 ps after the first echo. If the second echo component is searched for in this time range, the received signal can be evaluated in a simple and effective manner. In a further embodiment, the object is assumed to be a high object, which is located on a floor, if the second echo portion is detected in the time range. As already explained, the at least one window or a first window can be selected such that it covers the time range which follows the first echo portion. In this time range then echoes of the

Receive ultrasonic signal, which come from the multiple reflection of the ultrasonic signal. These multiple reflections occur on objects that are located on the ground or the road surface. In this way, the object can be characterized accordingly.

In another embodiment, a transit time is determined after which the first echo portion is received, and the time range is determined to include twice the transit time. The transit time describes the time which elapses between the emission of the ultrasound signal and the reception of the first echo or of the first echo component. In this case, the time range of the at least one window can be chosen such that it includes a double value of the transit time. In this way it can be checked whether the received signal describes portions of the ultrasonic signal which are caused by a multiple reflection between the ultrasonic sensor and the object. It can also be provided that a first window is defined for the time range which takes place directly on the first echo or the first echo and that a second window is defined which is determined to include twice the transit time. It allows an efficient evaluation of the received signal to further echo components or echoes, regardless of the threshold curve.

In a further embodiment, the time domain is assigned a time duration between 150 ps and 250 ps, in particular. This time range was determined based on searches and / or simulations. This time range is chosen so that in this possible second echo components can be reliably detected. Furthermore, the time range is chosen so that this brings a low computational burden.

In a further refinement, the amplitude range extends from a first amplitude value, which corresponds to at least 30% of the amplitude of the first echo component, to a second amplitude value, which corresponds to at least 70% of the amplitude of the first echo component. The second echo component usually has a lower amplitude than the first echo component of the received signal. Furthermore, the first amplitude value, which defines the lower limit of the amplitude range, is so too Select to avoid misinterpreting noise or noise as the second echo portion. This allows reliable detection of the second echo component.

A computing device according to the invention for an ultrasonic sensor of a

Motor vehicle is designed for performing a method according to the invention and the advantageous embodiments thereof. It can be provided in particular that the computing device is arranged in a housing of the ultrasonic sensor. Preferably, the computing device is designed as an application-specific integrated circuit (ASIC - Application-Specific Integrated Circuit). With the help of

Computing, an excitation signal can be sent, which for

Transmission of the ultrasonic signal is transmitted to the transducer element. Furthermore, the sensor signal, which is provided by the transducer element when receiving the ultrasound signal, can be received by means of the computing device, and the received signal can be determined therefrom.

Another aspect of the invention relates to an electronic control device for a

Motor vehicle, which designed for carrying out a method according to the invention and the advantageous embodiments thereof. By means of the electronic control unit (ECU - Electronic Control Unit), the excitation signal can be transmitted to the transducer element of the ultrasonic sensor. In addition, by means of the electronic

Control unit, the sensor signal, which is provided by the transducer element upon receiving the ultrasonic signal, are received, and from this, the received signal can be determined.

An inventive ultrasonic sensor for a motor vehicle comprises a

Computing device according to the invention. In addition, the ultrasonic sensor may have a membrane which is, for example, cup-shaped and may be made of a metal, for example aluminum. Furthermore, the

Ultrasonic sensor preferably a transducer element, which may be formed by a piezoelectric element. Furthermore, the ultrasonic sensor can have a housing in which the computing device or the sensor electronics are arranged.

An inventive driver assistance system for a motor vehicle comprises at least one ultrasonic sensor. In addition, the driver assistance system can be a

have electronic control unit. The driver assistance system can be configured, for example, as a parking aid system, which the driver when parking in a Parking space and / or when parking out of the parking space supported. Furthermore, provision can be made for the driver assistance system to be designed to maneuver the motor vehicle, at least semi-autonomously, as a function of the detected object or as a function of the estimated height of the object.

A motor vehicle according to the invention comprises an inventive

Driver assistance system. The motor vehicle is designed in particular as a passenger car. It can also be provided that the motor vehicle is designed as a commercial vehicle.

The invention also includes a computer program product with program code means which are stored in a computer-readable medium in order to carry out the method according to the invention and the advantageous embodiments thereof when the computer program product is processed on a processor of an electronic computing device of an ultrasound sensor and / or an electronic control unit.

A further aspect of the invention relates to a computer-readable medium, in particular in the form of a computer-readable floppy disk, CD, DVD, memory card, USB memory unit, or the like, are stored in the program code means to perform the inventive method and the advantageous embodiments thereof, if the

Program code means loaded in a memory of an electronic computing device of an ultrasonic sensor and / or an electronic control unit and on a processor of the electronic computing device and / or the electronic

Control unit to be processed.

The preferred embodiments presented with reference to the process according to the invention

Embodiments and their advantages apply correspondingly to the ultrasonic sensor device according to the invention, to the driver assistance system according to the invention, to the motor vehicle according to the invention for the computer program product according to the invention and to the computer-readable medium according to the invention.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures are not only in the respectively indicated combination, but also in others

Combinations usable, without departing from the scope of the invention. It is thus Also to consider embodiments of the invention as disclosed and disclosed, which are not explicitly shown and explained in the figures, but by separated

Feature combinations emerge from the described embodiments and can be generated. Embodiments and combinations of features are also to be regarded as disclosed, which thus do not have all the features of an originally formulated independent claim. Moreover, embodiments and combinations of features, in particular by the embodiments set out above, are to be regarded as disclosed which go beyond the feature combinations set out in the back references of the claims or deviate therefrom.

The invention will now be described with reference to preferred embodiments and with reference to the accompanying drawings.

Showing:

Fig. 1 shows a motor vehicle with a driver assistance system, which a

Comprising a plurality of ultrasonic sensors;

Fig. 2 is a schematic representation of the ultrasonic sensor, which is a

Computing device comprises;

Fig. 3 shows the ultrasonic sensor and a high object, which is located on a

Ground is located as well as the signal paths of the ultrasonic signal;

4 shows a received signal which reflects the object of FIG. 3

Describes ultrasonic signal as a function of time;

5 shows the ultrasonic sensor and an object according to another

Embodiment, wherein the object is a barrier;

Fig. 6 shows the ultrasonic sensor and an object according to another

Embodiment, wherein the object is arranged spaced from the ground; and 7 shows a received signal which describes a time profile of the ultrasound signal reflected by the object according to FIG. 6.

In the figures, the same or functionally identical elements are the same

Provided with reference numerals.

Fig. 1 shows a motor vehicle 1, which is presently designed as a passenger car, in a plan view. The motor vehicle 1 comprises a driver assistance system 2, which serves to assist a driver when driving the motor vehicle 1. For example, the driver assistance system 2 can be designed as a parking aid system, by means of which the driver can be supported when parking the motor vehicle 1 in a parking space and / or when parking out of the parking space.

The driver assistance system 2 comprises at least one ultrasound sensor 4. In the present exemplary embodiment, the driver assistance system 2 comprises twelve

Ultrasonic sensors 4, of which six ultrasonic sensors 4 are arranged in a front region 6 of the motor vehicle 1 and six ultrasonic sensors 4 in a rear region 7 of the motor vehicle 1. The ultrasonic sensors can in particular be mounted on a bumper of the motor vehicle 1. The can

Ultrasonic sensors 4 at least partially be arranged in corresponding recesses or through holes of the bumper. It can also be provided that the ultrasonic sensors 4 are arranged hidden behind the bumpers. In principle, the ultrasonic sensors 4 can also be arranged in other trim parts or components of the motor vehicle 1. For example, the ultrasonic sensors 4 may be arranged on or hidden behind the doors of the motor vehicle 1.

Receiving signals 10 (see FIG. 4), which describe at least one object 8 in a surrounding area 9 of the motor vehicle 1, can be respectively provided with the respective ultrasonic sensors 4. In the present case, an object 8 in the surrounding area 9 is shown schematically. To determine the received signal 10, an ultrasound signal can be emitted with each of the ultrasound sensors 4 and the ultrasound signal reflected by the object 8 can be received again. On the basis of a transit time tf between the emission of the ultrasound signal and the reception of the ultrasound signal reflected by the object 8, a distance d between the

Ultrasonic sensor 4 and the object 8 are determined. In addition, the driver assistance system 2 comprises an electronic control unit 3 which is connected to the respective ultrasonic sensors 4 for data transmission. Corresponding data lines or a data bus are presently not shown for clarity. Thus, the reception signals 10 provided with the respective ultrasonic sensors 4 can be transmitted to the electronic control unit 3. Based on the received signals 10, the control unit 3 can then check whether the object 8 is present in the surrounding area 9 and at which position the object 8 is located. As explained in more detail below, information which describes whether the object 8 is a tall object or a low object is also determined by means of the ultrasound sensor 4. These

Information can then be used by the driver assistance system 2 to output a corresponding output to the driver of the motor vehicle 1. In addition, it can be provided that the driver assistance system 2, the motor vehicle 1 in

Dependence on the detected object 8 at least semi-autonomously maneuvered.

For example, the motor vehicle 1 can be braked in front of a high object and a low object can be run over by the motor vehicle 1.

2 shows a greatly simplified representation of an ultrasonic sensor 4. It can be seen here that the ultrasonic sensor 4 has a membrane 11 which is pot-shaped and which can be made of a metal, in particular aluminum. In addition, the ultrasonic sensor 4 comprises a transducer element 12, which can be provided by a piezoelectric element. The transducer element 12 is in particular an electro-acoustic transducer. Furthermore, the ultrasonic sensor 4 comprises a computing device 5, which may be formed in particular by an application-specific intelligent circuit. The computing device 5 is connected to the

Transducer element 12 is electrically connected. When emitting the ultrasonic signal from the computing device 5, a corresponding excitation signal to the

Transducer element 12 are transmitted. Upon receiving the ultrasonic signal, a sensor signal, in the form of a temporally variable electrical voltage, can be transmitted to the computing device 5 with the transducer element 12. With the

Computing device 5, the received signal 10 can then be provided, which describes a time course of the vibrations of the membrane 1 1 and the transducer element 12 as a function of time t. Thus, the received signal 10 also describes the time profile of the ultrasonic signal reflected by the object 8. It is provided in particular that the received signal 10 describes an envelope or an envelope of the sensor signal. FIG. 3 shows a schematic representation of the ultrasonic sensor 4 and of the object 8, which in the present case is located on a floor 13 or the road surface. The ultrasonic sensor 4 is arranged at an installation height h on the motor vehicle 1, wherein the installation height h is known. The installation height h is defined with respect to a vertical axis of the motor vehicle 1. The object 8 may be, for example, a post or a wall. When the ultrasonic signal from the

Ultrasonic sensor 4 is emitted, this is reflected directly on the object 8 and returns to the ultrasonic sensor 4 back. This is illustrated here by the arrow 14. In addition, a portion of the emitted ultrasound signal at the contact point or foot point of the object 8 is reflected at the bottom 13. This is illustrated by the arrow 15 in the present case.

FIG. 4 shows a time profile of the received signal 16 of the ultrasonic signal reflected by the object 8 according to FIG. 3. In this case, the time t is plotted on the abscissa and an amplitude A is plotted on the ordinate. In the present case, it can be seen that the received signal 10 describes an envelope curve or an amplitude profile of the ultrasonic signal reflected by the object 8. This received signal 10 is compared with a predetermined threshold curve 17. This shows that

Receive signal 10 to a first echo portion 18, which exceeds the threshold curve 17. It is assumed that this first echo portion 18 of the

Reflection of the ultrasonic signal at the object 8 comes. This first echo portion 18 is received after the time tf. On the basis of this transit time tf and the knowledge of the speed of sound, the distance d between the ultrasonic sensor 4 and the object 8 can then be determined.

In the present case, it is provided that if the first echo component 18 is detected in the received signal 10, it is additionally checked whether a second echo component 19 is detected in a predetermined first window 20a. This is done independently of the

Threshold curve 17. This first window 20a is defined by a time range tb and by an amplitude range Ab. The amplitude range Ab extends from a first amplitude value A1 to a second amplitude value A2. The first

Amplitude value A1 may be about 30% of the amplitude A of the first echo portion 18 and the second amplitude value A2 may be about 70% of the amplitude A of the first

Echo portion 18 amount. The time domain tb may be associated with a duration of about 200 ps. Further, the time range tb is determined to be one

has predetermined time interval ta to the reception time of the first echo portion 18. For example, the time interval ta can be 50 ps. The second echo component 19 can be recognized in the received signal 10 by being assigned to a signal peak or a local maximum. If the second echo portion 19 is detected in the reception signal 10, it can

be assumed that it is a tall object 8, which is arranged on the floor 13. Thus, this object 8, which is a high and placed on the floor 13 object, for example, be distinguished from an object 8, which is approximately at the installation height h of the ultrasonic sensor 4, but not disposed on the floor 13. Such an object 8 is shown by way of example in FIG. 5. The object 8 according to FIG. 5 may be, for example, a

Barrier act. In this case, the received received signal 10 would only describe the first echo portion 18.

FIG. 6 shows the ultrasonic sensor 4 and another object 8. This is an object 8 which is arranged at a distance from the bottom 13. In addition, the object 8 in comparison to the object 8 according to FIG. 5 with respect to the vertical direction of the motor vehicle 1 on a larger spatial extent. In this case, in addition to the direct reflection of the ultrasound signal at the object 8 (arrow 14), there is additionally a multiple reflection of the ultrasound signal, at which the ultrasound signal is reflected back and forth between the ultrasound sensor 4 and the object 8. This is illustrated schematically in the present case by the arrows 21.

For this purpose, FIG. 7 shows the received signal 10, which describes the time profile of the ultrasonic signal reflected by the object 8 according to FIG. 6. Again, there is a first echo portion 18 of the received signal 10, which exceeds the threshold curve 17. This is received after the runtime tf. In this case, it is checked whether a second echo portion 19 is received in a second window 20b. In this case, the second window 20b or the time range tb of the second window 20b is selected such that it includes twice the transit time 2tf.

By evaluating the received signal 10, it can first be checked whether this has the first echo component 18. Following this, it can be checked in the window 20a and / or in the window 20b whether the second echo portion 19 can be detected there. If this is the case, it can be assumed that the object 8 is a tall object. This information can then be transmitted from the respective ultrasonic sensor 4 or its computing device 5 to the control unit 3. This information can then be provided by the driver assistance system 2 used to issue a warning to the driver and / or to maneuver the motor vehicle 1 at least semi-autonomously.

Claims

claims

1. A method for detecting an object (8) in an environmental region (9) of a motor vehicle (1), in which an ultrasonic sensor (4) is driven to emit an ultrasonic signal, a received signal (10) is determined which a temporal course of in describes the received signal (10) with a threshold curve (17) and if a first echo portion (18) of the received signal (10) exceeds the threshold curve (17), it is assumed that this first echo component ( 18) describes an echo of the ultrasonic signal reflected by the object (8),

characterized in that

if the first echo component (18) exceeds the threshold curve (17), it is checked independently of the threshold curve (17) whether the received signal (10) has at least one predetermined window (20a, 20b) a second echo component (19) which at least describes a signal peak of the received signal (10), and a height of the object is estimated on the basis of the first echo component (18) and / or the second echo component (19).

2. The method according to claim 1,

characterized in that

the object (8) is assumed to be high if the received signal (10) has the second echo portion (19).

3. The method according to claim 1 or 2,

characterized in that

the at least one predetermined window (20a, 20b) is assigned to a time domain (tb) and / or an amplitude domain (Ab) of the received signal (10), the time domain (tb) and / or the amplitude domain (Ab) being dependent on the first Echo component (18) can be determined.

4. The method according to claim 3,

characterized in that

the time range (tb) is a predetermined time interval (ta) to the first Echo portion (18), wherein the time interval (ta) as a function of a distance (d) to the object (8) and / or a mounting position of the

Ultrasonic sensor (4) is predetermined.

5. The method according to claim 4,

characterized in that

the object (8) is assumed to be a high object located on a floor (13) if the second echo portion (19) is detected in the time domain (tb).

6. The method according to any one of claims 3 to 5,

characterized in that

a term (tf) is determined, after which the first echo portion (18) is received, and the time range (tb) is determined to include twice the transit time (tf).

7. The method according to any one of claims 3 to 6,

characterized in that

the time domain (tb) has a time duration between 150 ps and 250 ps,

in particular 200 ps, is assigned.

8. The method according to any one of claims 3 to 7,

characterized in that

the amplitude range (Ab) of a first amplitude value (A1), which corresponds to at least 30% of an amplitude (A) of the first echo portion (18), to a second amplitude value (A2), which at least 70% of the amplitude (A) of the first Echo portion (18) corresponds, extends.

9. computing device (5) for an ultrasonic sensor (4) of a motor vehicle (1), which is designed for carrying out a method according to one of the preceding claims.

10. Ultrasonic sensor (4) for a motor vehicle (1) with a computing device (5) according to claim 9.

1 1. Driver assistance system (2) for a motor vehicle (1), with at least one

Ultrasonic sensor (4) according to claim 10 and with an electronic control unit (3).

12. Computer program product with program code means, which in one

computer-readable medium are stored to perform a method according to any one of claims 1 to 8, when the computer program product is executed on a processor of a computing device (5).

13. Computer-readable medium, in particular in the form of a computer-readable floppy disk, CD, DVD, memory card, USB memory unit, or the like, in which

Program code means are stored to a method according to one of

Claims 1 to 8 perform when the program code means in a memory of a computing device (5) loaded and on a processor of the

Processing device (5) are processed.