WO2018019696A1

WO2018019696A1 - Method for sensing an object in an environment of a vehicle comprising height determination, driver assistance system, and vehicle

Info

Publication number: WO2018019696A1
Application number: PCT/EP2017/068340
Authority: WO
Inventors: Alice FRAPSAUCE; Mohamed-Elamir MOHAMED
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2016-07-26
Filing date: 2017-07-20
Publication date: 2018-02-01
Also published as: DE102016113736A1

Abstract

The invention relates to a method for sensing an object (8) in an environment (7) of a vehicle (1), wherein an ultrasonic signal is emitted by means of an ultrasonic sensor (4), a first echo of the ultrasonic signal reflected by the object (8) is received, and an amplitude (A) of the first echo is determined, wherein the amplitude (A) of the first echo is compared with at least one predefined threshold value (a, β, δ) and a height of the object (8) is determined (S2) on the basis of the comparison of the amplitude (A) with the at least one threshold value (α, β, δ), wherein the object (8) is classified as high if the amplitude (A) of the first echo is greater than the at least one threshold value (α, β, δ) and the object (8) is classified as low if the amplitude (A) of the first echo is lower than the at least one threshold value (α, β, δ), and wherein a confidence value is determined for the classification of the height of the object (8), wherein the confidence value is defined as high if the height of the object (8) is classified as low or high and the confidence value is otherwise defined as low.

Description

Method for detecting an object in an environment of a vehicle with height determination, driver assistance system and vehicle

The present invention relates to a method for detecting an object in an environment of a vehicle, in which with an ultrasonic sensor

Transmitted ultrasound signal, a first echo of the reflected ultrasound signal from the object is received and an amplitude of the first echo is determined, the object is classified as high, if the amplitude of the first echo is greater than the at least one threshold, and the object as is classified low if the amplitude of the first echo is lower than the at least one threshold.

Furthermore, the present invention relates to a driver assistance system for a vehicle. Finally, the present invention relates to a vehicle with such

Driver assistance system.

In the present case, the interest is directed in particular to ultrasonic sensors which are used, for example, in driver assistance systems of vehicles. For example, ultrasound sensors may be part of a driver assistance system with which the vehicle can be maneuvered or parked at least semi-autonomously. The ultrasonic sensors can detect objects in the vicinity of the vehicle. For this purpose, an ultrasonic signal can be emitted with the ultrasonic sensor, which is then reflected by the object and in turn reaches the ultrasonic sensor. Based on the transit time between the emission of the ultrasound signal and the reception of the echo of the ultrasound signal, a distance between the vehicle and the object can then be determined. In this case, the amplitude of the reflected ultrasound signal or of the echo can also be determined.

In particular, if the vehicle is based on the measurements of the

Ultrasonic sensors is maneuvered at least semi-autonomous, it is desirable to determine the height of the detected objects. When the ultrasound signal is emitted and reflected at the object, there are usually several signal paths for the ultrasound signal reflected by the object or for the echoes. In a direct measurement with the ultrasound sensor, in which the ultrasound sensor emits the ultrasound signal and also receives the reflected ultrasound signal again, describes the direct signal path of the ultrasonic signal, the first echo. If the object is a tall object, the second echo comes from the object

Ultrasound signal, which is first reflected on the object and then on the ground. The signal path of the second echo is therefore longer than that of the first echo. To estimate the height of the object, the time interval between the first echo and the second echo can be determined. If the time interval between the received echoes is relatively low, for example, a high object can be assumed. If the time interval between the received echoes is relatively large, it can be assumed, for example, that two objects arranged one behind the other have been detected. If no second echo is received, a low obstacle is usually assumed.

Furthermore, it is known to determine the height of the object while the vehicle is moving toward the object. When the vehicle is approaching an object lower than the installation height of the sensor, it changes with the

Ultrasonic sensor measured distance in an unexpected way. If in this case the

Differences between the measured distances are calculated, it is possible to estimate the height of the object after a certain time or after a certain path.

Currently, it is difficult to distinguish low objects from high objects based on the received ultrasound signals. In some situations, too few second echoes are obtained to classify the height of the objects based on the difference between the first and second echoes. This is the case, for example, when the object relatively poorly reflects the ultrasonic signal due to the shape of the object, the material or the surface. Likewise, problems arise when ultrasonic signals are encoded accordingly, since in this case too many echo signals are filtered out. For example, if the height of the object can not be reliably determined based on the measurements with the ultrasonic sensor, a collision with an object may be imminent.

For this purpose, EP 2 607 919 A1 describes a method for contactless detection of an object in an environment of a vehicle, in which a plurality of ultrasound transmission signals are emitted in a transmission interval and at least one ultrasound transmission signal is reflected at the object, which receive as a reception signal and depending on the object is detected. It can also be provided that a plurality of ultrasonic transmission signals with different signal amplitudes is emitted, and it is determined in received received signals, how many signal amplitudes are above an amplitude threshold. Depending on this, the height and / or width of the detected object can be determined.

Furthermore, EP 2 073 038 A2 describes a method for classifying distance data from a distance detection system, in which measuring signals are transmitted and received by measuring signals reflected at distant objects by a sensor. In addition, the time between transmission and reception of the measurement signals is determined and there is a correlation of the time with a distance. In addition, the method includes correlating the statistical dispersion of the distance data with the height of the reflective object.

It is an object of the present invention to provide a solution as to how a height of an object in an environment of a vehicle can be more reliably determined by means of an ultrasonic sensor.

This object is achieved by a method by a

Driver assistance system and solved by a vehicle with the features according to the respective independent claims. Advantageous developments of the present invention are the subject of the dependent claims.

In one embodiment of a method for detecting an object in an environment of a vehicle, an ultrasound signal is emitted with an ultrasound sensor. Furthermore, a first echo of the ultrasound signal reflected by the object is preferably received, and an amplitude of the first echo is determined. In addition, the amplitude of the first echo is preferably compared with at least one predetermined threshold value and the height of the object is determined on the basis of the comparison of the amplitude with the at least one threshold value. In this case, the object is preferably classified as high if the amplitude of the first echo is greater than the at least one threshold, and the object is particularly classified as low if the amplitude of the first echo is lower than the at least one threshold. Furthermore, a confidence value for the classification of the height of the object is preferably determined, the confidence value preferably being set high if the height of the object is classified as low or high, and

Confidence value otherwise set low. An inventive method is used to detect an object in an environment of a vehicle. In this case, an ultrasonic signal is emitted with an ultrasonic sensor. Further, a first echo of the reflected from the object

Receive ultrasonic signal and an amplitude of the first echo is determined. Furthermore, the amplitude of the first echo is compared with at least one predetermined threshold value, and a height of the object is determined on the basis of the comparison of the amplitude with the at least one threshold value. In addition, if the amplitude of the first echo is greater than the at least one threshold, the object is classified as high, and the object is classified as low if the amplitude of the first echo is lower than the at least one threshold. In addition, a confidence value is determined for the classification of the height of the object, the confidence value being set high if the height of the object is classified as low or high, and the confidence value otherwise being set low.

Subsequently, the height of an object or an obstacle in the surroundings of the vehicle is to be determined or estimated with at least one ultrasonic sensor. The ultrasonic sensor can be part of a

Driver assistance system of the vehicle, can be at least semi-autonomously maneuvered with the vehicle. In order to capture the object in the environment or to classify the height of the object, the

Ultrasound sensor performed at least one measurement cycle. In a measurement cycle, a direct measurement can be carried out with the ultrasonic sensor, in which initially an ultrasonic signal is emitted. For this purpose, a membrane of the ultrasonic sensor can be excited with a corresponding traveling element to mechanical vibrations. Furthermore, at least a first echo of the ultrasound signal is received by the ultrasound sensor in the measurement cycle. The first echo corresponds to the ultrasound signal reflected by the object, which returns to the ultrasound sensor on the direct path or signal path. The first echo can correspond to the proportion of the emitted ultrasound signal, which after being transmitted is first received again by the ultrasound sensor. When the first echo or the reflected ultrasonic signal hits the membrane of the ultrasonic sensor, it is excited to mechanical vibrations. These vibrations can then be detected with the transducer element. The

Transducer element may for example comprise a piezoelectric element which can convert the mechanical vibration of the membrane into an electrical alternating voltage. This electrical voltage can be, for example, the raw signal of the ultrasonic sensor, which describes the first echo. From this raw signal can then the amplitude can be determined. The amplitude of the first echo or of the raw signal describes the sound pressure level of the first echo. It can also be provided that an indirect measurement is carried out. For this purpose, the ultrasound signal is emitted with a first ultrasound sensor and the ultrasound signal reflected by the object is received by a second ultrasound sensor, which is different from the first ultrasound sensor. Here, the first echo originates in particular from the proportion of the ultrasound signal emitted by the first ultrasound sensor, which propagates directly from the first ultrasound sensor to the object and from the object to the second ultrasound sensor.

It is now provided that the amplitude of the first echo is compared with at least one predetermined threshold value. It can also be provided that a plurality of threshold values are predetermined and the amplitude of the first echo is compared with this. Based on the comparison of the amplitude with the at least one threshold value, the height of the object can then be determined or estimated. This is based on the knowledge that the amplitude of the first echo or the raw signal of the first echo describe the reflection properties of the object. In this case, it is also taken into account that the ultrasound signal is reflected better by a relatively high object than by one

relatively low object. The ultrasonic sensor has a

Transmission characteristic on. This means that the ultrasonic signal has a higher sound pressure level, for example, along a main transmission direction, which can be perpendicular to the diaphragm. When the ultrasonic signal is reflected by a high object which is in the main transmitter direction, the first echo has a higher amplitude than a low echo, which is arranged below the main transmitter direction, for example. When evaluating the amplitude of the first echo, the amplitude of the emitted ultrasound signal or the sound pressure level of the emitted ultrasound signal can be taken into account. Thus, based on the amplitude of the first echo, the height of the object in the surroundings of the vehicle can be estimated in a simple manner.

It can also be provided that the amplitude of a second echo, a third echo, a fourth echo and / or a fifth echo of the emitted

Ultrasonic signal is received and the respective amplitude is determined.

Basically any number of echoes of the transmitted ultrasonic signal can be received and their respective amplitudes can be determined. These amplitudes can then be compared to corresponding threshold values. In a direct Measurement, the second echo describe the reflected ultrasound signal from the object, which after the emission first on the object and then on another object, for example on the ground, on which the vehicle and the object may be located, reflected and then from the Ultrasonic sensor is received. After the transmission of the ultrasound signal, first the first echo, then the second echo, then the third echo, etc., can be received. The ordinal numbers of the echoes can thus describe their temporally successive reception times. This applies equally to the indirect measurement. Because the respective amplitudes are determined by a plurality of echoes of the emitted ultrasound signal, a plurality of objects can be detected. For example, two high obstacles, which are arranged one behind the other, can be detected.

Furthermore, if the amplitude of the first echo is greater than the at least one threshold, the object is classified as high and the object is classified as low if the amplitude of the first echo is less than the at least one threshold. This at least one threshold may be determined based on empirical values or measurements previously made with a plurality of different objects. Thus, by comparing the amplitude of the first echo with the at least one threshold, it can be easily determined whether the object is a tall object or a low object. As a low object is in particular such an object to understand, which can be run over, for example, with the vehicle. Such a low object may be, for example, a curb. In particular, the low object has such a height that no damage to the body of the vehicle by the low object can take place. A high object is in particular such an object, which can lead to a collision with the vehicle and in particular damage to the body of the vehicle. In particular, a high object represents an obstacle for the vehicle. The classification can easily prevent collisions with high objects.

According to an essential aspect of the present invention, it is provided that a confidence value for the classification of the height of the object is determined, wherein the confidence value is set high if the height of the object is classified as low or high, and the confidence value otherwise is set low. In addition to classifying the object based on the amplitude of the first echo, a confidence value for that classification may be specified. Of the Confidence value can be either high or low. A high confidence value results if the object can be unambiguously or safely classified as a high or a low object. This is the case when the object is based on the

Comparison of the amplitude of the first echo with the threshold is uniquely recognized as a high object or as a low object. If the object can not be uniquely classified, a low confidence value is set. Here, the object can not be safely characterized based on the comparison of the amplitude with the threshold. In this case, the height of the object can be set as unknown. This allows evaluation of the classification based on the amplitude. Thus, the determination of the height of the object overall

be carried out more reliably.

Furthermore, it is advantageous if a second echo of the ultrasound signal reflected by the object is received, a time difference between the reception of the first echo and the reception of the second echo determined and the

Classification of the height of the object is additionally carried out on the basis of the time difference. In addition to the first echo of the ultrasound signal, a second echo can be received. The second echo describes the ultrasound signal reflected by the object, which, after being transmitted, is first transmitted to the object and

then reflected on another object and then from the

Ultrasonic sensor is received. If the time duration between receiving the first echo and the second echo falls below a predetermined threshold, it can be considered to be a high object. If the time difference between the reception of the first echo and the second echo is relatively large, it can be assumed, for example, that two objects arranged one after the other have been detected, if no second echo has been received, it can be assumed that it is is a low object. Thus, the height of the object may additionally be classified based on the second echo.

In this case, it is provided in particular that the classification of the height is determined on the basis of the time difference, if the confidence value is set as low, and the classification is determined on the basis of the amplitude of the first echo, if the confidence value is set as high. If the confidence value is set high, the height of the object was surely classified based on the amplitude of the first echo. In this case, the classification is based on the amplitude of the first echo. If the confidence value is set low or, the height of the object could not be reliably determined based on the amplitude of the first echo. In this case, then the

Classification of the object based on the time difference between the first and the second echo can be performed.

Furthermore, it is advantageous if, based on the first echo, a distance between the ultrasound sensor and the object is determined and the at least one threshold value is predetermined as a function of the distance. This takes into account that the ultrasonic signal is attenuated due to the airborne sound attenuation. This is true for both the transmitted ultrasound signal and that reflected by the object

Ultrasound signal too. The farther the object is from the ultrasonic sensor, the greater the airborne sound attenuation. Based on the first echo, the distance between the ultrasonic sensor and the object can be determined. For this purpose, the transit time between the emission of the ultrasound signal and the reception of the first echo can be used. Depending on the distance between the

Ultrasonic sensor and the object can then be adapted to the at least one threshold. For example, the at least one threshold can be reduced with increasing distance. Thus, the threshold, which is used to classify the object, can be adapted to the situation.

It can also be provided that the relative position between the ultrasonic sensor and the object is determined. The relative position between the ultrasonic sensor and the object can be determined by triangulation. Furthermore, provision may be made for the information to be used by further sensors of the vehicle or of the driver assistance system in order to determine the relative position between the ultrasound sensor and the object. In particular, it may be determined how the object is related to the main transmit direction of the

Ultrasonic sensor is arranged. Based on the transmission characteristic of the

Ultrasonic sensor can then be determined the transmission sound pressure of the ultrasonic signal, which impinges on the object. Thus, depending on the relative position between the ultrasonic sensor and the object and / or the transmission characteristic of the ultrasonic sensor, the at least one threshold value can be adjusted and thus the object can be reliably classified.

In one embodiment, the object is classified as high if the distance is less than a first threshold and the amplitude is greater than a first threshold, or if the distance is between the first threshold and a second threshold, and the amplitude is greater than a second threshold. The first and the second

Threshold values can be determined on the basis of empirical values or based on measurements already taken. For example, if the distance determined based on the first echo is less than or equal to a first threshold and the amplitude of the first echo is greater than the first

Threshold, it can be assumed that the object is a tall object. Thus, a first range may be specified for the distance that extends from the ultrasonic sensor to the first threshold. If the object is in this range, the amplitude of the first echo may be compared to the first threshold. Further, a second range may be specified for the distance extending from the first threshold to the second threshold. If the object is located in this area and the

Amplitude of the first echo is greater than a second threshold, it can be assumed that it is a high object. The second threshold may be less than the first threshold. This allows a simple classification of the object.

Furthermore, it is preferably provided that the object is classified as low if the distance is greater than a third threshold and the amplitude is smaller than a third threshold. If the object is further than the third limit of the

Ultrasonic sensor is removed and the amplitude is less than the third threshold, it can be assumed that it is a low object. Thus, a simple classification of the object can also be made possible here.

In a further embodiment, the at least one threshold is in

Dependent on a current speed of the vehicle and / or a temperature in the environment of the vehicle and / or a humidity in the environment of the vehicle predetermined. It is therefore also possible to determine the relative speed between the vehicle and the object in order to determine the at least one threshold value. Thus, the change of the relative position between the ultrasonic sensor and the object can be considered. In addition, the temperature in the environment of the vehicle can be detected by means of a corresponding sensor. In this case, it is possible for the temperature, which is output for example in an instrument cluster of the vehicle, to be used to determine the temperature in the surroundings of the vehicle. This takes into account that the temperature in the environment has a significant effect on the

Airborne sound attenuation has. Furthermore, it can be provided that the humidity in the environment of the vehicle is determined, including these effects on the

Airborne sound attenuation has. Thus, the airborne sound attenuation in the vicinity of the vehicle can be estimated and the threshold value can be adjusted accordingly.

In a further refinement, the at least one threshold value is determined as a function of an amplitude of a first echo of an ultrasound signal reflected by the object received at an earlier time. It can also be provided that amplitudes of first echoes, which were determined in earlier measurement cycles, are used to determine the at least one threshold value. In principle, it can also be provided that the comparison of the amplitude of the first echo with the at least one threshold value is carried out for two consecutive first echoes from the same object. Furthermore, it can be considered that the at least one threshold value is adapted, depending on whether successive first echoes are present or not. Thus, a reliable classification of the object can be done.

An inventive driver assistance system for a vehicle is designed for carrying out a method according to the invention. The driver assistance system may include at least one ultrasonic sensor. Preferably, this includes

Driver assistance system, a plurality of ultrasonic sensors, which may be arranged distributed to the vehicle, for example. Furthermore, the driver assistance system may include a control device, which may be formed for example by an electronic control unit of the vehicle. By means of the control device, the at least one ultrasonic sensor for emitting the ultrasonic signal can be controlled. Furthermore, the sensor data, which were determined by means of the ultrasonic sensor, can be evaluated with the control device.

A vehicle according to the invention comprises an inventive

Driver assistance system. The vehicle may be designed as a motor vehicle and in particular as a passenger car.

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

Embodiments and their advantages apply correspondingly to the driver assistance system according to the invention and to the vehicle 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 mentioned above in the description and Combinations of features, as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respectively specified combination but also in other combinations or alone, without departing from the scope of the invention. Thus, embodiments of the invention are to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, however, emerge and can be produced by separated combinations of features from the embodiments explained. 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 or deviate from the combinations of features set out in the back references of the claims.

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

Showing:

1 shows a vehicle according to an embodiment of the present invention in a plan view.

2 is a schematic flowchart of a method for detecting a

Object in the vicinity of the vehicle;

Fig. 3 different limits for a distance between a

Ultrasonic sensor and the object; and

4 is a schematic flow diagram of a method for classifying a height of the object.

In the figures, the same and functionally identical elements with the same

Provided with reference numerals.

Fig. 1 shows a vehicle 1 according to an embodiment of the present invention in a plan view. The vehicle 1 is in the present case as a passenger car educated. The vehicle 1 comprises a driver assistance system 2, which serves to assist a driver of the vehicle 1 when driving the vehicle 1.

For example, the driver assistance system 2 can serve to park the vehicle 1 at least semi-autonomously in a parking space or to maneuver the vehicle 1 at least semi-autonomously.

The driver assistance system 2 comprises a control device 3, which may be formed for example by an electronic control unit of the vehicle 1. In addition, the driver assistance system 2 comprises at least one ultrasonic sensor 4. In the present exemplary embodiment, the driver assistance system 2 comprises eight

Ultrasonic sensors 4, wherein four ultrasonic sensors 4 are arranged in a front region 5 and four ultrasonic sensors 4 in a rear region 6 of the vehicle 1. The ultrasonic sensors 4 can, for example, in corresponding openings of the

Bumpers or concealed behind the bumpers of the vehicle 1 may be arranged.

With the ultrasonic sensors 4 objects 8 can be detected in an environment 7 of the vehicle 1. For this purpose, each of the ultrasonic sensors 4 emit an ultrasonic signal, which is then reflected by the object 8 and back to the

Ultrasound sensor 4 comes back. From the ultrasonic signal reflected from the object 8, various echoes can be received. For example, a first echo may be received which is transmitted along the direct signal path from the object 8 to the ultrasound sensor 4. Furthermore, a second echo can be received which originates from the ultrasound signal which is first reflected at the object 8 and subsequently from a ground or a vehicle surface and then reaches the ultrasound sensor. Furthermore, provision can be made for an amplitude A of the first and / or the second echo of the ultrasound signal to be determined with the aid of the corresponding ultrasound sensor 4. The amplitude A of the echo describes in particular the sound pressure level of the reflected ultrasound signal or the echo.

By means of the ultrasonic sensors 4, a height of the object 8 is now to be determined. In particular, the height of the object 8 should be classified as low or high. 2 shows a schematic flowchart of a method for detecting the object 8 in the surroundings 7 of the vehicle 1. The method is started in a step S1. In a step S2, the amplitude A of the first echo of the

Ultrasonic signal determined. The amplitude A of the first echo is then compared with at least one predetermined threshold value α, β, δ. Depending on the Comparing the amplitude A of the first echo with the at least one threshold a, β, δ, the height of the object 8 is classified. For example, the object 8 may be classified as low if the amplitude A of the first echo is less than the at least one threshold α, β, δ. Furthermore, the object 8 can be classified as high if the amplitude A of the first echo is greater than the at least one

predetermined threshold value α, β, δ. In addition, in step S2, a

Confidence value which describes the determination of the height of the object 8 on the basis of the amplitude A of the first echo. If the object 8 has been surely classified as high or low based on the amplitude A of the first echo, the confidence value is set high. Otherwise the confidence level is set low. In this case, the height of the object 8 can be assumed to be unknown.

In a step S3, in addition to the first echo, a second echo of the

Receive ultrasonic signal. In addition, a time difference between receiving the first echo and the second echo is determined. Based on the time difference between receiving the first echo and the second echo, the height of the object 8 can then also be classified. If the time difference between receiving the first echo and the second echo falls below a predetermined threshold, it can be assumed that the object 8 is a high object. If the time difference exceeds the threshold or if no second echo is received, it can be assumed that the object 8 is low.

In a step S4, it is checked whether the confidence value has been set high or low. If the confidence value has been set high, the process proceeds to a step S5. In this case, the height of the object 8 is classified based on the amplitude A of the first echo. If the query in step S4 shows that the confidence value has been set as low, the method is continued in step S6. In this case, the classification of the height of the object 8 is based on the time difference between the first echo and the second echo. Finally, the process is ended in a step S7.

Fig. 3 shows a schematic representation of a distance d between the

Ultrasonic sensor 4 and the object 8. For the distance d several limit values X, Y and Z are specified. If the distance d is smaller than the first limit value X, it is checked whether the amplitude A of the first echo is greater than or equal to a first one Threshold α is. If this is the case, it can be assumed that the object 8 is a tall object. If the distance d between the

Ultrasonic sensor 4 and the object 8 between the limits X and Y, it is checked whether the amplitude A of the first echo is greater than or equal to a second threshold ß. If this is the case, it can be assumed that the object 8 is a tall object. If the distance d is greater than a third threshold Z, it is checked whether the amplitude A is less than or equal to a third threshold δ. If this is the case, it can be assumed that the object 8 is a low object. In the described cases, the object 8 can be unambiguously or safely classified as a high object or a low object. In this case, the confidence value is set high. In all other cases the confidence level is set low.

4 shows a schematic flow chart of a method for classifying the height of the object 8. The method is started in a step S8. In a step S9, a query is made as to whether a first echo has already been detected by the same object 8 at an earlier time. If a first echo has not yet been received for the object 8, the method is continued in a step S10. Here, the amplitude A of the first echo can be determined and with the at least one

Threshold α, ß, δ are compared. Again, as described in connection with FIG. 3, different limit values X, Y, Z for the distance d between the ultrasonic sensor 4 and the object 8 can be specified. Both the limit values X, Y, Z and the threshold values α, β, δ can be adapted if no first echo has yet been received for the same object 8. Depending on the comparison of the amplitude A with the threshold values α, β, δ, the object 8 can then be classified as high in a step S1 1 or the object 8 can be classified as low in a step S12 or the object 8 in a step S13 classified as unknown.

If the query in step S9 shows that a first echo has already been received by the object 8, the method is set in step S14. Here, the distance d between the ultrasonic sensor 4 and the object 8 is determined. In a step S15, the amplitude A of the first echo, which was determined at an earlier time, is determined. In a step S16, the amplitude A of the currently determined first echo is determined. In a step S17, the amplitude A is compared with the threshold values α, β, δ. The threshold values α, β, δ and / or the limit values X, Y, Z for the distance d as a function of the distance d, the Amplitude A of the current echo and / or the amplitude A of the previously determined first echo can be adjusted. Thus, also here, the object 8 can be classified as high (step S1 1), as low (step S12) or as unknown (step S13). In a step S18, the process is then terminated.

Claims

claims

1 . Method for detecting an object (8) in an environment (7) of a vehicle (1) in which an ultrasound signal is emitted with an ultrasound sensor (4), a first echo of the ultrasound signal reflected by the object (8) is received and an amplitude (A) of the first echo is determined, wherein the amplitude (A) of the first echo with at least one predetermined threshold (α, ß, δ) is compared and a height of the object (8) based on the comparison of the amplitude (A) with the at least one threshold value (α, β, δ) is determined (S2), wherein the object (8) is classified as high if the amplitude (A) of the first echo is greater than the at least one threshold value (α, β, δ) and the object (8) is classified as low if the amplitude (A) of the first echo is lower than the at least one threshold (α, β, δ),

characterized in that

a confidence value is determined for the classification of the height of the object (8), the confidence value being set high if the height of the object (8) is classified as low or high, and the confidence value otherwise being set low.

2. The method according to claim 1,

characterized in that

a second echo of the ultrasound signal reflected from the object (8) is received, a time difference between receiving the first echo and receiving the second echo is determined, and the classification of the height of the object (8) is additionally performed on the basis of the time difference ( S3).

3. The method according to claim 1 or 2,

characterized in that

the classification of the height of the object (8) is determined from the difference in time if the confidence value is set low (S6) and the classification of the height of the object (8) from the amplitude (A) of the first one Echo is determined if the confidence value is set high (S5).

4. The method according to any one of the preceding claims,

characterized in that

A distance (d) between the ultrasonic sensor (4) and the object (8) is determined on the basis of the first echo, and the at least one threshold value (α, β, δ) is predetermined as a function of the distance (d).

5. The method according to claim 4,

characterized in that

the object (8) is classified as high if the distance (d) is less than a first threshold (X) and the amplitude (A) is greater than a first threshold (a) or if the distance (d) is between the first Limit (X) and a second threshold (Y) and the amplitude (A) is greater than a second threshold (ß).

6. The method according to claims 4 or 5,

characterized in that

the object (8) is classified as low if the distance (d) is greater than a third threshold (Z) and the amplitude (A) is less than a third threshold (δ).

7. The method according to any one of the preceding claims,

characterized in that

the at least one threshold value (δ) as a function of a current one

Speed of the vehicle (1) and / or a temperature in the environment (7) of the vehicle (1) and / or a humidity in the environment (7) of the vehicle (1) is predetermined.

8. The method according to any one of the preceding claims,

characterized in that

the at least one threshold value (α, β, δ) is determined as a function of an amplitude (A) of a first echo of an ultrasound signal reflected by the object (8) received at an earlier time.

9. driver assistance system (2) for a vehicle (1), which is designed for carrying out a method according to one of the preceding claims.

10. Vehicle (1) with a driver assistance system (2) according to claim 9.