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US-12625259-B2 - Method for characterising an object in an environment of a motor vehicle

US12625259B2US 12625259 B2US12625259 B2US 12625259B2US-12625259-B2

Abstract

The present disclosure relates to a method for characterizing an object in an environment of a motor vehicle by an assistance system of the motor vehicle, in which method the motor vehicle is moved relative to the object and ultrasonic signals are emitted with an ultrasonic sensor of the assistance system. Echoes of the ultrasonic signals reflected by the object are received, wherein, by a control device, respective amplitudes of the received echoes are ascertained, and a classification of a height of the object is determined based on the amplitudes. The classification of the height of the object is determined based on a determined first change in amplitude by comparing a first amplitude of a first echo with a second amplitude of a second echo received after the first echo. An assistance system is disclosed having an ultrasonic sensor and a control device designed to carry out such a method.

Inventors

  • Abhishek Kekud
  • Robin Adams
  • Sahar Khawatmi
  • Nicolai Glatz

Assignees

  • Continental Autonomous Mobility Germany GmbH

Dates

Publication Date
20260512
Application Date
20210922
Priority Date
20200930

Claims (19)

  1. 1 . A method for characterizing an object in an environment of a motor vehicle by an assistance system of the motor vehicle, the method comprising: performing, by the assistance system, at least one of an assisted, semi-automatic, or automatic parking method, which includes: emitting continually ultrasonic signals with an ultrasonic sensor of the assistance signal of the motor vehicle while the motor vehicle moves relative to the object; receiving echoes of the ultrasonic signals reflected by the object; ascertaining, by a control device of the motor vehicle, respective amplitudes of the received echoes; and classifying a height of the object based on the ascertained amplitudes, wherein the classification of the height of the object is determined on the basis of a determined first change in amplitude by comparing a first amplitude of a first echo of a first ultrasonic signal with a second amplitude of a second echo of a second ultrasonic signal, wherein the second echo was received after the first echo, wherein the classification of the height of the object is determined when the first change in amplitude is above a predefined threshold, which is determined as a function of at least a current speed of the motor vehicle, wherein the classification of the height of the object is determined on the basis of a comparison of the first change in amplitude with a second change in amplitude, and the second change in amplitude is determined by comparing a third amplitude of a third echo of a third reflected ultrasonic signal which was received after the second echo with the second amplitude of the second echo or with a fourth amplitude of a fourth echo of a fourth reflected ultrasonic signal, wherein the fourth echo was received after the second echo and before the third echo; and localizing and dimensioning a parking space using at least the classified height of the object for parking the motor vehicle during at least one of the assisted, semi-automatic, or automatic parking method.
  2. 2 . The method according to claim 1 , wherein the first echo and the second echo are temporally successive echoes.
  3. 3 . The method according to claim 1 , wherein the object is located in the vicinity of the motor vehicle, when the motor vehicle approaches the object, the object is classified as low if an amplitude decrease over a course of time is determined as the first change in amplitude, and the object is classified as high if an amplitude increase over the course of time is determined as the first change in amplitude.
  4. 4 . The method according to claim 3 , wherein the object is located in the vicinity of the motor vehicle at a distance of up to two meters from the ultrasonic sensor of the motor vehicle.
  5. 5 . The method according to claim 1 , wherein when the motor vehicle approaches the object, the object is classified as low if an amplitude increase over the course of time is determined as the first change in amplitude and an amplitude decrease over the course of time is determined as the second change in amplitude.
  6. 6 . The method according to claim 1 , wherein the object is located in the vicinity of the motor vehicle, when the motor vehicle approaches the object, the object is classified as low if an amplitude decrease over the course of time is determined in each case as the first change in amplitude and as the second change in amplitude, and if the second change in amplitude is additionally greater than the first change in amplitude.
  7. 7 . The method according to claim 6 , wherein the object is located in the vicinity of the motor vehicle at a distance of up to two meters from the ultrasonic sensor of the motor vehicle.
  8. 8 . The method according to claim 1 , wherein the object is located in the vicinity of the motor vehicle, when the motor vehicle approaches the object, the object is classified as high if an amplitude increase over the course of time is in each case determined as the first change in amplitude and as the second change in amplitude, and if the second change in amplitude is additionally greater than the first change in amplitude.
  9. 9 . The method according to claim 1 , wherein the predetermined threshold is further determined as a function of at least one of a temperature in the environment of the motor vehicle, a humidity in the environment of the motor vehicle, or an installation height of the ultrasonic sensor on the motor vehicle.
  10. 10 . The method according to claim 1 , wherein the comparison of the amplitudes is based on at least one of a difference or a relationship of the amplitudes.
  11. 11 . The method according to claim 1 , wherein the comparison of the changes in amplitude is based on at least one of a difference or a relationship of the changes in amplitude.
  12. 12 . The method according to claim 1 , wherein the classification of the height of the object is exclusively based on sensor data of the ultrasonic sensor.
  13. 13 . The method according to claim 1 , comprising: receiving at least one of temperature and humidity measurements from one or more additional sensors; and adjusting the predefined threshold based on the at least one temperature and humidity measurement.
  14. 14 . The method according to claim 1 , comprising: sending a notification to a driver of the motor vehicle based on the heigh classification of the object.
  15. 15 . The method according to claim 1 , wherein the object is located below a sightline of the driver of the motor vehicle.
  16. 16 . An assistance system, comprising: an ultrasonic sensor configured to continually emit ultrasonic signals when a motor vehicle is moved relative to an object, and receive echoes of the ultrasonic signals reflected by the object; and a control device configured to ascertain respective amplitudes of the received echoes and classify a height of the object based on the ascertained amplitudes, wherein to classify the height of the object the control device is configured to determine a first change in amplitude by comparing a first amplitude of a first echo of a first ultrasonic signal with a second amplitude of a second echo of a second ultrasonic signal, the second echo being received after the first echo, wherein the classification of the height of the object is determined when the first change in amplitude is above a predefined threshold, which is determined as a function of at least a current speed of the motor vehicle, wherein the classification of the height of the object is determined on the basis of a comparison of the first change in amplitude with a second change in amplitude, and the second change in amplitude is determined by comparing a third amplitude of a third echo of a third reflected ultrasonic signal which was received after the second echo with the second amplitude of the second echo or with a fourth amplitude of a fourth echo of a fourth reflected ultrasonic signal, wherein the fourth echo was received after the second echo and before the third echo, wherein the control device is further configured to localize and dimension a parking space using at least the classified height of the object for parking the motor vehicle during at least one of an assisted, semi-automatic, or automatic parking method.
  17. 17 . An assistance system for a vehicle, comprising: an ultrasonic sensor configured to continually emit ultrasonic signals while the vehicle moves relative to an object; a controller configured to receive echoes from at least one ultrasonic sensor that are reflected by the object in an environment of the vehicle, ascertain amplitudes of amplitudes of the received echoes, determine a classification of a height of the object based upon the ascertained amplitudes, wherein the classification of the height of the object is determined based on a determined first change in amplitude by comparing a first amplitude of a first echo of the received echoes of a first ultrasonic signal with a second amplitude of a second echo of the received echoes of a second ultrasonic signal, the echoes of the second ultrasonic signal being was received after the echoes of the first ultrasonic signal, wherein the classification of the height of the object is determined when the first change in amplitude is above a predefined threshold, which is determined as a function of at least a current speed of the motor vehicle, wherein the classification of the height of the object is determined on the basis of a comparison of the first change in amplitude with a second change in amplitude, and the second change in amplitude is determined by comparing a third amplitude of a third echo of a third reflected ultrasonic signal which was received after the second echo with the second amplitude of the second echo or with a fourth amplitude of a fourth echo of a fourth reflected ultrasonic signal, wherein the fourth echo was received after the second echo and before the third echo, wherein the controller is further configured to localize and dimension a parking space using at least the classified height of the object for parking the motor vehicle during at least one of an assisted, semi-automatic, or automatic parking method.
  18. 18 . The assistance system of claim 17 , wherein the first echo and the second echo are temporally successive echoes.
  19. 19 . The assistance system of claim 17 , wherein the object is located in the vicinity of the motor vehicle, and when the motor vehicle approaches the object, the object is classified as low if an amplitude decrease over a course of time is determined as the first change in amplitude, and the object is classified as high if an amplitude increase over the course of time is determined as the first change in amplitude.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/DE2021/200125 filed on Sep. 22, 2021, and claims priority from German Patent Application No. 10 2020 212 381.0 filed on Sep. 30, 2020, in the German Patent and Trademark Office, the disclosures of which are herein incorporated by reference in their entireties. TECHNICAL FIELD The present disclosure relates to a method for characterizing an object in an environment of a motor vehicle by means of an assistance system of the motor vehicle, in which method the motor vehicle is moved relative to the object and ultrasonic signals are emitted with an ultrasonic sensor of the assistance system. Echoes of the ultrasonic signals reflected by the object are received and, by means of a control device, respective amplitudes of the received echoes are ascertained, wherein a classification of a height of the object is ascertained based on the amplitudes. The present disclosure further relates to an assistance system having an ultrasonic sensor and a control device which is designed to carry out such a method. BACKGROUND Ultrasonic sensors usually include a transmitting device which emits ultrasonic signals which propagate in air at the speed of sound, namely approximately 340 meters per second. To this end, a membrane of the ultrasonic sensor is commonly excited to mechanical vibrations with a corresponding transducer element. The ultrasonic signal is reflected as an echo by objects in the environment and is detected by a receiver device of the ultrasonic sensor. The spacing or, in other words, the distance from the object can be ascertained on the basis of the difference in transit time between the time of transmission and the time of reception, taking account of the propagation speed of the ultrasonic signal. In this case, the amplitude of the reflected ultrasonic signal or of the echo can also be determined. Ultrasonic sensors are usually deployed in motor vehicles to capture the surroundings in a range of up to approximately 7 meters. In particular, ultrasonic sensors are particularly important during semi-automatic or automatic driving maneuvers, especially in connection with parking applications, for instance for measuring parking distances, looking for parking spaces or when parking. The motor vehicle is usually moved relative to the objects, wherein a measuring cycle is carried out in each case when the vehicle is moved at previously ascertained points in time. During each measuring cycle, an ultrasonic signal is emitted with an ultrasonic sensor. Methods and corresponding assistance systems are already known from the prior art, which provide the driver with different information regarding the environment of the motor vehicle with the aid of ultrasonic sensors and which support him during maneuvering of the motor vehicle and, in particular, during the locating of a parking space and when parking the motor vehicle in the parking space. Assistance systems exist, for example, which are equipped with parking space localization and which notify the driver whether a parking space is available in the immediate environment of the motor vehicle or whether an available parking space is large enough in order to be able to park the motor vehicle therein. Such assistance systems need information about objects located in the environment of the motor vehicle, which can be formed, for example, by parked vehicles, curbs, and walls, for secure localization and dimensioning of a parking space. In addition to the distance of the motor vehicle from an object, the height of the object is also usually of significance. The height is an important factor in being able to decide whether an object or obstacle can be driven over or not. In particular, when the motor vehicle is maneuvered at least semi-autonomously on the basis of the measurements of an ultrasonic sensor, it is desirable to ascertain the height of the captured object. The height is ascertained with one-dimensional (1D) ultrasonic sensors, that is to say ultrasonic sensors for ascertaining the distance, which are regularly used in the motor vehicle sector; this process is in principle very difficult due to physical limitations. The height of an object cannot be measured directly with the aid of such an ultrasonic sensor. In order to ascertain the height, a camera is therefore additionally used, for example, and the height is estimated based on a 2D image, or a method based on multiple sensors is used for estimating the height on the basis of triangulation. However, methods based on a camera or multiple sensors do not exploit the advantages of a 1D ultrasonic sensor in terms of costs and robustness. A method and an assistance system of the type previously indicated are known, for example, from DE 10 2004 047 479 A1. In order to classify a height of an object, when a motor vehicle drives past the object located to the si