Obstacle profile using vertical resolution of ultrasound

Abstract

The invention relates to a method for generating a vertically resolved obstacle contour (118) for a vehicle (100) using ultrasound waves, comprising the steps of: recording (S2) a plurality of echo curves received in response to emission (S1) of respective emission signals, the transmit signals are generated at different ultrasonic frequencies using an ultrasonic transducer (108) having a frequency-based transmit characteristic; providing (S3), for each ultrasonic frequency, a description of the emission characteristics of the ultrasonic transducer (108), said description assigning emission intensities for a plurality of emission angles (122) on a vertical plane; determining (S4) individual emission angles (122) and obstacle distances (120) of the signals contained in the echo curves by comparing the reception intensity difference of the signals between the at least two echo curves with the emission intensity difference between signal characteristics, the ultrasonic frequency of which is the ultrasonic frequency of the emitted signal; and generating (S7) an obstacle profile by combining the determined launching angles with the respective corresponding obstacle distances.

Description

[0001] The present invention relates to a method for constructing a vertically resolved obstacle profile for a vehicle by means of ultrasound, and also relates to a control device, an ultrasonic transducer and a vehicle.

[0002] There is a need to identify the vertically resolved profile of an obstacle located in front of the vehicle's driving direction. A practical application scenario could be parking the vehicle forward into a parking space with a ventilation duct installed on the ceiling. For example, if the vehicle to be parked has a slender hood, as is the case with a sedan or a station wagon, the entire length of the parking space can be utilized since the hood occupies the space below the ventilation duct. However, in this example, if the ventilation duct is misidentified as an obstacle, the triggered obstacle warning may unsettle and / or distract the driver. Another application scenario could be differentiating between a curb that can be driven over and a wall that cannot.

[0003] U.S. Patent Application Publication No. 2020 / 0201347 A1 discloses a self-propelled device having a housing, a moving module, a driving module and a control module. The moving module is designed to drive the housing, and the driving module is designed to drive the moving module to move. The control module is designed to control the self-propelled device. A sensor assembly for non-contact obstacle recognition is arranged on the housing. After the obstacle recognition sensor assembly detects an obstacle in the moving direction, which is the forward driving direction of the self-propelled device, the control module controls the self-propelled device to continue moving and controls its movement until the obstacle is avoided. Taking an automatic lawn mower as an example, it is illustrated that only obstacles within a certain height range can be detected, and different viewing directions of the ultrasonic sensor can be determined by different mounting heights and tilting angles.

[0004] Therefore, using multiple ultrasonic sensors with different mounting heights and / or tilting angles to obtain a vertically resolved obstacle profile results in a complex system structure and high cost.

[0005] Against this background, the object of the present invention is to provide an improved method, in particular a reliable and low-cost technique for constructing a vertically resolved obstacle profile.

[0006] The above object is achieved by presenting a method for constructing a vertically resolved obstacle profile for a vehicle by means of ultrasound. The method comprises the steps of: recording a plurality of echo responses received in response to the emission of respective emission signals, the emission signals being generated at different ultrasonic frequencies by an ultrasonic transducer having frequency-dependent emission characteristics; providing a description of the emission characteristics of the ultrasonic transducer for each ultrasonic frequency, the description attributing emission intensities to a plurality of emission angles in a vertical plane; determining the emission angle and the obstacle distance of the signals comprised in the echo responses by comparing the difference in received intensity of the signals between at least two echo responses with the difference in emission intensity between the signal characteristics of the emission signal having the ultrasonic frequency of the ultrasonic frequencies; and constructing an obstacle profile by combining the determined emission angles with the respective associated obstacle distances.

[0007] The method exploits the effect that an ultrasonic transducer can have frequency-dependent emission characteristics. If the obstacle is not located in the main direction of the ultrasonic transducer, but is diagonally offset relative to the main direction, then the emission intensity of the emission signal transmitted towards the exemplary obstacle depends on the ultrasonic frequency of the emission signal. This difference in emission characteristics can directly result in a difference in ultrasonic echo intensity. If the frequency-dependent emission characteristics are known, the angle between the main direction and the obstacle can be inferred from the difference in ultrasonic echo intensity. Thus, a vertically resolved obstacle profile can be obtained without the need for additional ultrasonic sensors.

[0008] The term "vertical plane" preferably refers to the stationary position of the vehicle when it is in a state to be driven on a horizontal surface. The vertical plane is preferably a plane perpendicular to the current surface below the vehicle. If the vehicle is driving on an uneven surface, the vertical plane may not be perpendicular. However, given the spatial resolution achieved by the ultrasonic sensors, this effect can generally be neglected in the case of a conventional road surface. The ultrasonic sensors, the plurality of ultrasonic sensors and / or each ultrasonic sensor used in the method are preferably mounted on the vehicle in a manner fixed to the vehicle body.

[0009] The term "vertically resolved obstacle profile" preferably refers to the aggregation of the respective distances to the obstacle at a plurality of heights. The obstacle profile may involve non-detection of the obstacle at one or more heights. The vertically resolved obstacle profile is preferably constructed for a vertical plane.

[0010] Options and aspects are outlined below which have advantages over the basic form of the proposed method and which thus further improve the method. The presented options and aspects can be combined.

[0011] According to a preferred option, determining the emission angle and the obstacle distance includes performing the following steps on a plurality of recorded echo responses: identifying a test signal by comparing a first echo response recorded at a first ultrasonic frequency and a second echo response among the plurality of recorded echo responses recorded at a second ultrasonic frequency, the test signal having a difference in received intensity between the first echo response and the second echo response, and identifying, in a vertical plane, the emission angle corresponding to the test signal if the difference in received intensity corresponds to the difference in emission intensity between the emission intensity of the first ultrasonic frequency for a certain emission angle and the emission intensity of the second ultrasonic frequency for that emission angle. In other words: If the difference in received intensity corresponds to the difference in emission intensity between the emission intensity of the first ultrasonic frequency for a certain emission angle and the emission intensity of the second ultrasonic frequency for that emission angle, then identify, in a vertical plane, the emission angle corresponding to the test signal.

[0012] According to an option, if the propagation time of the first signal and the propagation time of the second signal differ by no more than 10%, preferably no more than 7%, more preferably no more than 4%, then the first test signal included in the first echo response corresponds to the second signal included in the second echo response. These tolerances allow for different reflection points on the obstacle to be taken into account. Thus, the method can correctly identify, for example, a large area on the obstacle as an obstacle.

[0013] According to an option, if the difference in received intensity and the difference in emission intensity differ by no more than 35%, more preferably no more than 25%, even more preferably no more than 12.5%, then the difference in received intensity corresponds to the difference in emission intensity. In this way, the method can reliably identify obstacles having, for example, frequency-dependent reflection behavior and / or a wide-range diffuse reflection behavior.

[0014] According to another option, an ultrasonic transducer having a main axis is used to emit the emission signal, the main axis extending downward, horizontally, and / or upward by at most 20° from the ultrasonic transducer in the radiation direction. Thus, it can be stipulated that the method is carried out using ultrasonic transducers that can hitherto typically be installed in a vehicle to identify obstacles. The indicated directions can preferably relate to, for example, a stationary vehicle that is unloaded and in a state ready to travel above a horizontal surface.

[0015] According to another option, the same ultrasonic transducer is used to transmit the transmission signal and receive the echo response. This means that, for example, the method can be implemented at lower cost. Additionally or alternatively, a different ultrasonic transducer than the one that transmitted the echo response is used to receive the echo response. This allows, for example, an obstacle directly in front of the vehicle to be identified. Furthermore, for example, if in particular the receiving ultrasonic transducer is laterally offset in the same direction, an obstacle that is laterally offset relative to the ultrasonic transducer that transmitted the transmission signal can be reliably identified. If multiple ultrasonic transducers distributed in the horizontal direction are used for reception, an obstacle with multiple vertically resolved obstacle profiles can be detected in space. Preferably, multiple ultrasonic transducers distributed at least in the horizontal direction are used to receive the respective echo responses. Preferably, the following steps are performed for each ultrasonic transducer: recording multiple echo responses and determining the emission angle and the obstacle distance of the signal contained in the echo response.

[0016] According to another option, the method can include the following steps: determining the horizontal position of the obstacle by evaluating the propagation time differences of test signals received by multiple ultrasonic transducers distributed at least in the horizontal direction. For example, knowing the relative positions of the ultrasonic transducers that received the test signals, or the relative positions of the ultrasonic transducer that transmitted the transmission signal and / or received the test signal, enables an obstacle that reflected the test signal to be identified in space. Thus, better information about the position of the obstacle can be provided to the driver.

[0017] If multiple obstacle profiles are constructed, as an improvement, the method can provide for combining the respective obstacle profiles into a three-dimensional obstacle profile. For example, this may be particularly suitable for superposition and / or comparison with scan results (such as scan results from a laser scanner, image recognition, and / or a three-dimensional map).

[0018] It is possible that different transmission angles are or can be attributed to the test signal based on different echo responses. This can be triggered, for example, by frequency-dependent reflection behavior. This phenomenon can occur when a single ultrasonic transducer transmits and receives, one ultrasonic transducer transmits while another ultrasonic transducer receives, one ultrasonic transducer transmits and that ultrasonic transducer and at least one other ultrasonic transducer receive, and one ultrasonic transducer transmits while multiple other ultrasonic transducers receive. For example, in all these cases, the position of the obstacle can be determined more precisely by the method including the following steps: determining the minimum, average, or maximum transmission angle associated with the test signal in the vertical plane. As an improvement, it can be stipulated that the minimum value is determined for transmission angles above the main axis of the transmitting ultrasonic transducer (for example, transmission angles more than 30° above the main axis). Additionally or alternatively, as an improvement, it can be stipulated that the average value is determined for transmission angles close to the main axis of the transmitting ultrasonic transducer (for example, transmission angles in the range from 30° above the main axis to 10° below the main axis). As an improvement, it can be stipulated that the maximum value is determined for transmission angles below the main axis of the transmitting ultrasonic transducer (for example, transmission angles below 10° below the main axis). For example, these improvements are advantageous for a vehicle whose ultrasonic transducers are mounted on the most prominent body parts. For safety reasons, these improvements ensure the localization of the obstacle closest to the ultrasonic transducer.

[0019] There may be a situation where the ultrasonic transducer has frequency-dependent reception characteristics, the amplitude of which is related to the accuracy of the method proposed herein. In this case, to obtain higher accuracy, one option proposed is that the method includes the following steps: for one or each ultrasonic transducer for receiving multiple echo responses for each ultrasonic frequency, providing a description of the reception characteristics, each reception characteristic description being the reception intensity of the transmitted pulse at different reception angles in the vertical plane. Additionally, it is recommended to process each echo response by filtering with the corresponding reception characteristics. Alternatively, the description of the reception characteristics can be combined with the description of the transmission characteristics and provided for one or each receiving ultrasonic transducer.

[0020] For example, to facilitate the signal processing of the method, and / or for example, to effectively execute the method in parallel, it can be stipulated that the ultrasonic transducers transmit the transmission signals in the order of ultrasonic frequencies. Particularly preferably, the transmission signals are arranged in ascending order of ultrasonic frequency, that is, starting from the lowest ultrasonic frequency which usually has the widest transmission angle. It is also particularly preferably that the method is executed continuously and / or repeatedly such that immediately after the transmission signal of the highest ultrasonic frequency is the transmission signal of the lowest ultrasonic frequency.

[0021] This method is particularly suitable for facilitating vehicle control in a limited space (such as a parking lot or a parking space). For example, to save energy, it is advantageous if this method is only executed within a specified maximum speed. For example, this maximum speed can reach 50 km / h, and more preferably can reach 30 km / h.

[0022] In addition, a computer program product is proposed, which contains instructions that, when executed by a computer, cause the computer to execute the above method. This computer product has the characteristics and advantages of the method executed or capable of being executed.

[0023] The computer program product, such as a computer program device, can be provided or supplied, for example, as a storage medium (such as a memory card, USB flash drive, CD - ROM, DVD), or in the form of a file that can be downloaded from a network server. For example, this can be achieved in a wireless communication network by transmitting the corresponding file containing the computer program product or the computer program device.

[0024] The initially determined goal is achieved by proposing a vehicle control device. The control device can be coupled to at least one ultrasonic transducer (including a set of matching ultrasonic transducers) for information transmission. For example, it can be coupled to at least one ultrasonic transducer via a bus. The control device is configured to execute the above method, preferably in the form of the computer program product as described above. The control device has the characteristics and advantages of the method executed or capable of being executed.

[0025] In addition, the proposed control device can also be part of a vehicle's upper - level control system, such as a central electronic control device and / or an engine control unit (ECU: Engine Control Unit).

[0026] The control device can include, for example, a recording device (such as a volatile memory) and / or an interface, especially for recording multiple echo responses. The control device can include, for example, a storage device (such as a volatile or non - volatile memory), especially for providing the transmission characteristics of the ultrasonic transducer for each ultrasonic frequency. The control device can include, for example, an execution device (such as a processor), especially for respectively determining the transmitted signal and the obstacle distance and constructing the obstacle profile.

[0027] Each device can be implemented in hardware and / or software form. In the case of hardware implementation, each device can be, for example, in the form of a computer or a microprocessor. In the case of software implementation, each device can be in the form of a computer program product, function, routine, algorithm, partial program code, or an executable object.

[0028] The object initially specified is achieved by providing an ultrasonic transducer for a vehicle. The ultrasonic transducer is configured to carry out the method described above. In order to implement some options and / or aspects of the method described above, the ultrasonic transducer may optionally be configured to be able to couple with at least one ultrasonic transducer, including as part of a set of matching ultrasonic transducers, for information transmission. The ultrasonic transducer provided has the features and advantages of the method carried out or capable of being carried out.

[0029] The ultrasonic transducer may in particular include an ultrasonic transducer device, a recording device, a storage device, and / or an execution device.

[0030] Finally, the object initially mentioned is also achieved by providing a vehicle having at least the control device and / or the ultrasonic sensor described above. The vehicle has the features and advantages of the method, the control device, and / or the ultrasonic transducer carried out or capable of being carried out.

[0031] If the control device and the ultrasonic sensor are present simultaneously, the method steps may be carried out in a manner distributed over the ultrasonic sensor and the control device. This also applies to multiple ultrasonic sensors and / or multiple control devices.

[0032] Other possible implementations of the invention also include combinations of the features or embodiments described above or below with respect to the exemplary embodiments that are not explicitly mentioned. In this case, the person skilled in the art will also add the respective aspects as improvements or supplements to the corresponding basic forms of the invention.

[0033] Other advantageous configurations and aspects of the invention form the subject matter of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below on the basis of preferred embodiments and with reference to the drawings.

[0034] Figure 1 A schematic plan view of an exemplary vehicle having a plurality of ultrasonic sensors and a control device is shown;

[0035] Figure 2 A schematic side view of a vehicle having an ultrasonic sensor, which implements the method according to a first embodiment of the invention, is shown;

[0036] Figure 3 A schematic side view of a step of the method according to a first embodiment of the invention is shown; and

[0037] Figure 4 A schematic flow chart of the method according to the first embodiment is shown.

[0038] Unless otherwise specified, identical or functionally identical elements are denoted by the same reference numerals in the figures.

[0039] Figure 1A schematic top view of the vehicle 100 is shown. The vehicle 100 is, for example, an automobile arranged in the environment 102. The automobile 100 has a control device 104 which, for example, includes a parking assistance system.

[0040] In addition, a plurality of environmental sensor devices 106, 108 are arranged on the automobile 100, which may be, for example, an optical sensor 106 and an ultrasonic sensor 108. The optical sensor 106 includes, for example, a visible camera, radar and / or lidar. Each optical sensor 106 can capture an image of a corresponding area in the environment 102 around the automobile 100 and output the image as an optical sensor signal. The ultrasonic sensor 108 is designed to detect the distance to an object arranged in the environment 102 and output a corresponding sensor signal. Using the sensor signals captured by the sensors 106, 108, the control device 104 can, for example, drive the automobile 100 partially autonomously or fully autonomously. In addition to Figure 1 the optical sensor 106 and the ultrasonic sensor 108 shown in, the vehicle 100 may also be provided with various other sensor devices 106, 108. For example, examples of these sensor devices are microphones, acceleration sensors, antennas with coupling receivers for receiving electromagnetic transmissible data signals, and so on.

[0041] Figure 2 A side view of the vehicle 100 is shown, in which an ultrasonic sensor 108 is shown. The ultrasonic transducer 108 has a horizontally extending main axis H. There is an obstacle 110 in the environment 102, which has a contour 112 facing the vehicle.

[0042] The method according to the invention will be described below in conjunction with Figure 4 the flow chart in.

[0043] The method has a plurality of sub-steps S1-1 to S1-4, which are collectively referred to as a step S1. The method also has a plurality of sub-steps S2-1 to S2-4, which are collectively referred to as a step S2.

[0044] In a first sub-step S1-1, the ultrasonic transducer 108 emits an emission signal 114-1 at an ultrasonic frequency. Subsequently, in sub-step S2-1, the ultrasonic transducer 108 and the control device 104 record an echo response. If the emission signal 114 hits the obstacle 110, the reflected signal is reflected back to the ultrasonic transducer 108 and recorded in the echo response. Together with the echo response, the ultrasonic frequency of the emission signal is also recorded.

[0045] After sub-step S1-2, sub-step S2-1 is carried out, in which an emission signal 114-2 is emitted. In response to this emission, an echo response is recorded in sub-step S2-2.

[0046] Therefore, the transmission signals 114-1 to 144-4 are repeatedly transmitted in sub-steps S1-1 to S1-4, and the echo responses are recorded in each of sub-steps S2-1 to S2-4.

[0047] For example, in the case of the first embodiment, four different ultrasonic frequencies are used. For each ultrasonic frequency, the method includes a sub-step S1 for transmission and a sub-step S2 for recording the corresponding echo response.

[0048] As Figure 2 schematically depicted in [reference], the ultrasonic transducer 108 has frequency-dependent transmission characteristics. For clarity, each of the four transmission signals 114-1 to 114-4 is represented by a sector. The sector representing the transmission signal 114-1, which symbolizes the lowest ultrasonic frequency, has the largest central angle. Additionally, the sector representing the transmission signal 114-4, which symbolizes the highest ultrasonic frequency, has the smallest central angle. These sectors symbolize the high transmission intensity ranges of the corresponding transmission signals 114. The representation by sectors is a simplification: in reality, the transmission intensity usually does not drop suddenly but decreases gradually as the angle relative to the main direction of the ultrasonic transducer increases. Figure 2 The sectors in [reference] are shown with different radii. This is another simplification: in reality, although the transmission signals 114 of different ultrasonic frequencies have different ranges, the transmission intensity usually does not drop suddenly but decreases gradually as the distance from the ultrasonic sensor 108 increases.

[0049] Figure 2 and Figure 3 Exemplarily, ten reflections 116-1 to 116-10 are shown. The echo response recorded as a response to the transmission of the transmission signal 114-1 of the lowest ultrasonic frequency includes, for example, the signals for reflections 116-1, 116-2, 116-8, 116-9, and 116-10. The echo response recorded as a response to the transmission of the transmission signal 114-2 of the second lowest ultrasonic frequency includes, for example, the signals for reflections 116-3, 116-7, 116-8, and 116-9. The echo response recorded as a response to the transmission of the transmission signal 114-3 of the second highest ultrasonic frequency includes, for example, the signals for reflections 116-6 and 116-7. The echo response recorded as a response to the transmission of the transmission signal 114-4 of the highest ultrasonic frequency includes, for example, the signals for reflections 116-4, 116-5, and 116-6.

[0050] In the next step S3, a description of the signal characteristics of the ultrasonic transducer 108 is provided, for example, for each of the four ultrasonic frequencies. For example, four signal characteristic descriptions are thus provided. It should be noted that the signal characteristic description can be provided as a combined file, a combined table, or a software function or method. Each signal characteristic description attributes a corresponding transmission intensity to a plurality of transmission angles in the vertical plane. In other words: the transmission characteristic description indicates, for example, the transmission intensity distribution of the ultrasonic transducer 108 with respect to the transmission angle for the corresponding ultrasonic frequency.

[0051] In the next step S4, based on the transmission characteristic description, the transmission angle 118 and the obstacle distance 120 are determined for the signals contained in the echo response. For this purpose, the method uses at least one comparison result of at least one received intensity difference between at least two signals between at least two echo responses and at least one transmission intensity difference between the signal characteristics whose ultrasonic frequency is the ultrasonic frequency of the transmission signal, and these at least two echo responses are recorded as responses to these transmission signals.

[0052] For example, steps S5 and S6 are provided for this purpose.

[0053] In step S5, the test signal is first identified. This is achieved by comparing the first echo response in a recorded set of echo responses with the second echo response in the recorded set of echo responses. The first echo response is recorded when the transmission signal 114 is transmitted at the first ultrasonic frequency, and the second echo response is recorded when the transmission signal 114 is transmitted at the second ultrasonic frequency, and the second ultrasonic frequency is different from the first ultrasonic frequency. If the method finds a signal with a received intensity difference between the two echo responses in the two echo responses, then this signal is the test signal, which will be examined in more detail below.

[0054] The received intensity is, for example, the signal intensity of the received signal. For example, the echo response is first post-processed using known methods, such as filtering and / or smoothing. For example, artifacts such as ground echoes are filtered out by an algorithm. The received intensity corresponds, for example, to the amplitude of the peak in the echo response.

[0055] The received intensity difference can be expressed in absolute value, for example, in dB or volts. The received intensity difference can, for example, be expressed as a relative value in percentage based on the amplitude of the signal in the echo response at the lower ultrasonic frequency. The transmission characteristics are preferably such that the transmission intensity difference has the same nature (dB, volts, percentage) as the received intensity difference to be compared with it.

[0056] In step S6, each received intensity difference is compared with the transmitted intensity difference. In particular, there is a received intensity difference between two echo responses received in response to transmitted signals emitted at a specific ultrasonic frequency. In the above example, these are the first and second ultrasonic frequencies. Then, the transmission characteristics of the first and second ultrasonic frequencies are compared. For example, each angle in the transmission characteristics is examined to determine whether the transmitted intensity difference at that angle corresponds to the received intensity difference found in step S5.

[0057] The ultrasonic frequency is preferably in the range of 52 kHz ± 20 kHz, more preferably in the range of 52 kHz ± 12 kHz, still more preferably in the range of 52 kHz ± 6 kHz, and most preferably in the range of 52 kHz ± 3 kHz.

[0058] If, in the examination of step S6, the received intensity difference found in step S5 corresponds to the transmitted intensity difference between the transmitted intensity of the first ultrasonic frequency and the transmitted intensity of the second ultrasonic frequency at a certain transmission angle, then in the vertical plane, that transmission angle is identified as the transmission angle corresponding to the test signal.

[0059] Step S5 is performed for each signal included in the echo response. Step S6 is performed for each test signal found in step S5. In the examples of FIGS. 2 to 4, all 10 reflected signals 116-1 to 116-10 are regarded as test signals.

[0060] Therefore, as a result of steps S5 and S6, in the upper-level step S4, there is a set of values including the obstacle distance and the transmission angle, or there are multiple sets of such values, or there are no such sets of values. If the obstacle distance cannot be associated with the transmission angle, the method is terminated.

[0061] In the next step S7, an obstacle profile 118 is constructed. For example, this obstacle profile 118 is as shown in FIG. 3. As shown by the test signal for reflection 116-2, the position of the reflection is calculated based on the obstacle distance 120 determined in step S5 and the transmission angle 122 determined in step S6. As a result, the positions of 10 reflections 116-1 to 116-10 are calculated.

[0062] A preferred optional post-processing step identifies test signals at road level so that such test signals are not included in the construction of the obstacle profile 118. Therefore, reflections 116-8 to 116-10 can be ignored when constructing the obstacle profile 118.

[0063] Constructing the obstacle contour 118 includes, for example, drawing a continuous line through positions obtained by combining the identified emission angles (122) with their respective associated obstacle distances (120).

[0064] Comparing FIGS. 2 and 3, it can be seen that the actual obstacle contour 112 in FIG. 2 is slightly different from the constructed or identified obstacle contour 118 in FIG. 3. This difference is generally tolerable because when approaching the obstacle, preferably the methods S1 to S7 are repeatedly executed, and because the methods S1 to S7 are generally used to provide the driver with a general direction.

[0065] In this example, the vehicle 100 or at least a part of the vehicle 100 shown in FIG. 3 can pass under the point on the obstacle 110 that generates the reflection 116-2. Therefore, the obstacle warning device can, for example, alert the driver to the approach of the reflection 116-2, but not warn of a collision with the point associated with the reflection 116-2. As a result, the driver can manoeuvre the vehicle 100 closer to the obstacle 110.

[0066] According to a second embodiment not shown in the figures, the method uses a plurality of ultrasonic transducers 108. For example, one ultrasonic transducer 108 is used to emit the emission signal 114, and a plurality of other horizontally distributed ultrasonic transducers 108 are used to receive and record the echo responses. Therefore, the receiving ultrasonic transducers 108 are arranged at different angles around the vertical axis of the vehicle 100.

[0067] For example, steps S2 and S4 to S7 are respectively executed for each of the plurality of receiving ultrasonic transducers 108. Therefore, it is stipulated that each of the plurality of receiving ultrasonic transducers 108 records a plurality of echo responses in step S3 to determine a plurality of emission angles and obstacle distances in multiple executions of steps S4 to S6, and then determines the corresponding obstacle contour 118 in step S7.

[0068] This means that a plurality of obstacle contours 118 are determined, each obstacle contour being associated with a vertical plane. For example, when these vertical planes are known, the control device 104 can thus better alert the driver of the vehicle 100 to obstacles in the surrounding environment 102.

[0069] In a variant, instead of executing step S7 for each individual receiving ultrasonic transducer 108, it is executed jointly for all sets of values of all the ultrasonic transducers 103 in order to directly obtain the three-dimensional obstacle contour 118.

[0070] In a variant of this embodiment, in the next step, a combined obstacle profile is constructed from a plurality of obstacle profiles 118. Thus, it will be a three-dimensional obstacle profile. For example, this three-dimensional obstacle profile can be used for comparison with a stored three-dimensional model of a parking lot and / or with an image or model of the surrounding environment 102 obtained by the optical sensor 106.

[0071] Although the present invention has been described based on exemplary embodiments, the present invention can be modified in various ways.

[0072] List of reference signs

[0073] 100 Vehicle

[0074] 102 Surrounding environment

[0075] 104 Control device

[0076] 106 Optical sensor

[0077] 108 Ultrasonic sensor

[0078] 110 Obstacle

[0079] 112 Profile

[0080] 114 Transmitted signal

[0081] 116 Reflection

[0082] 118 Obstacle profile

[0083] 120 Obstacle distance

[0084] 122 Transmission angle

[0085] H Main axis

Claims

1. A method for constructing a vertically resolved obstacle profile (118) for a vehicle (100) by means of ultrasound, comprising the steps of: recording (S2) a plurality of echo responses received in response to the emission (S1) of respective emission signals, the emission signals being generated at different ultrasonic frequencies by an ultrasonic transducer (108) having frequency-dependent emission characteristics, providing (S3) for each ultrasonic frequency a description of the emission characteristics of the ultrasonic transducer (108), the description attributing emission intensities to a plurality of emission angles (122) in a vertical plane, determining (S4) the emission angle (122) and the obstacle distance (120) of the signals comprised in the echo responses by comparing the difference in received intensity between the signals of at least two echo responses with the difference in emission intensity between the signal characteristics of the ultrasonic frequencies of the emission signals of which the ultrasonic frequencies are those of the emission signals, and constructing (S7) the obstacle profile by combining the determined emission angles with the respectively associated obstacle distances.

2. The method according to claim 1, wherein Determining (S4) the emission angle (122) and the obstacle distance (120) comprises: performing the following steps on the recorded plurality of echo responses: identifying (S5) a test signal by comparing a first echo response recorded at a first ultrasonic frequency and a second echo response among the recorded echo responses recorded at a second ultrasonic frequency, the test signal having a difference in received intensity between the first echo response and the second echo response, and identifying (S6) the emission angle (122) in the vertical plane corresponding to the test signal if the difference in received intensity corresponds to the difference in emission intensity between the emission intensity of the first ultrasonic frequency at a certain emission angle and the emission intensity of the second ultrasonic frequency at the emission angle (122).

3. The method according to any one of the preceding claims, characterized in that, The emission signals are emitted (S1) using an ultrasonic transducer (108) having a main axis (H) which extends downwards, horizontally and / or upwards from the ultrasonic transducer (108) in a radiation direction by at most 20°.

4. The method according to any one of the preceding claims, characterized in that, The ultrasonic transducer (108) emits the emission signals in order of ultrasonic frequency, the emission signals preferably being arranged in ascending order of ultrasonic frequency, and preferably being followed by the emission signal of the lowest ultrasonic frequency after the emission signal of the highest ultrasonic frequency.

5. The method according to any one of the preceding claims, characterized in that, The same ultrasonic transducer (108) is used to emit (S1) the emission signals and to receive the echo responses.

6. The method according to any one of the preceding claims, characterized in that, The ultrasonic transducer (108) for receiving the echo responses is different from the ultrasonic transducer for emitting (S1) the emission signals.

7. The method according to any one of the preceding claims, characterized in that, A plurality of at least horizontally distributed ultrasonic transducers (108) are used to receive the respective echo responses, and for each ultrasonic transducer (108) the following steps are performed: recording (S2) a plurality of echo responses; and determining (S4) the emission angle (122) and the obstacle distance (120) of the signals comprised in the echo responses.

8. The method according to any one of the preceding claims, characterized in that, The method comprises the step of determining the horizontal position of the obstacle or the obstacle part of the reflected signal by evaluating the difference in propagation time of the test signals received by a plurality of at least horizontally distributed ultrasonic transducers.

9. The method according to claim 8 further includes the step of determining a minimum, average, or maximum emission angle associated with the test signal in a vertical plane.

10. The method for constructing a three-dimensional obstacle contour according to any one of claims 5 to 9, characterized in that, The method includes the following steps: combining the respective obstacle profiles into a three-dimensional obstacle profile.

11. The method according to any one of the preceding claims, characterized in that, The method includes the following steps: providing a receiving characteristic for the ultrasonic transducer (108) or each ultrasonic transducer (108) for receiving a plurality of echo responses for each ultrasonic frequency, each receiving characteristic describing the receiving intensity of the transmitted pulse for different receiving angles in a vertical plane.

12. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 - 11.

13. A control device (104) for a vehicle (100) that can be coupled to at least one ultrasonic transducer (108) for information transmission and is configured to perform the method according to any one of claims 1 to 11.

14. An ultrasonic transducer (108) for a vehicle (100) that is configured to perform the method according to any one of claims 1 to 5, and preferably can be coupled to at least one additional ultrasonic transducer (108) for information transmission and is configured to perform the method according to any one of claims 6 to 11.

15. A vehicle (100) having the control device (104) according to claim 13 and / or the ultrasonic transducer (108) according to claim 14.

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