The present invention relates to a method for ascertaining an approximate object position of a dynamic object in the surroundings of a vehicle that includes two ultrasonic sensors and at least one camera. Moreover, the present invention relates to a computer program, including commands which, when the program is executed by a computer, prompt the computer to carry out the steps of the method according to the present invention. Furthermore, the present invention relates to a device, in particular a central or zonal processing unit or a control unit for a vehicle, including a processing unit that is configured in such a way that it carries out the steps of the method according to the present invention. Moreover, the present invention relates to a vehicle that includes this device.
A park pilot system for a vehicle typically includes multiple ultrasonic sensors, and an evaluation unit that detects and processes the data of the sensors and outputs warnings concerning possible obstacles. In addition, use of camera data or camera images is conventional in park pilot systems, as the result of which, for example, static and/or dynamic objects in the vehicle surroundings are recognized by trained machine recognition methods, based on image data, and further processed, for example, for emergency braking assistants and/or a visualization of the surroundings of the vehicle for the driver by generating a surround view or a top-down view with overlays or fade-ins of additional information. For these purposes, the detected camera images may be equalized, prepared, and transformed, for example, in particular with the aid of a central processing unit, with the aid of a zonal processing unit, or with the aid of a control unit.
The ultrasonic sensors of a park pilot system are generally situated in each case at the front and rear bumpers of a vehicle, over the entire vehicle width, for ascertaining data regarding the distance between the vehicle and objects in the surroundings of the vehicle. The ultrasonic sensors are typically configured to emit an ultrasonic signal. This emitted ultrasonic signal is reflected at obstacles. The reflected ultrasonic signal is once again received by the ultrasonic sensors as an echo signal, and from the propagation time a distance from the obstacle is computed. The ascertainment of the distance generally takes place as a function of a propagation time of a direct and/or indirect echo signal, or of a direct and/or indirect reflected ultrasonic signal or reflection signal for an emitted ultrasonic signal. The determination of the distance typically takes place with the aid of a sensor ASIC situated in a housing of the ultrasonic sensor. The sensor data of an ultrasonic sensor thus represent or include, for example, the reflected ultrasonic signal or the received echo signal and/or the computed distance as well as optional properties of the received echo signal, in particular relative to the emitted ultrasonic signal. A reflection origin position may typically be ascertained according to the trilateration principle as a function of at least one directly and one indirectly received echo signal and/or as a function of at least two directly received echo signals or at least two indirectly received echo signals. The trilateration principle presumes, for example, that the ultrasonic sensor neighboring an emitting ultrasonic sensor to the right and/or left is configured to receive a cross echo or the received echo signal or the indirect reflection signal for the emitted ultrasonic signal. The determination of the reflection origin position preferably takes place with the aid of a processing unit, for example with the aid of a microcontroller, that is situated in the control unit or in the zonal or central processing unit, for example, this processing unit, preferably a processor, advantageously detecting and processing sensor data of multiple, in particular neighboring, ultrasonic sensors.
German Patent Application No. DE 10 2010 045 657 A1 provides a surroundings monitoring system for a vehicle, the surroundings monitoring system including at least two distance sensors for distance recognition via propagation time measurement of detection signals.
German Patent Application No. DE 10 2019 205 565 A1 provides a method for assessing an object height based on received ultrasonic signals.
German Patent Application No. DE 10 2018 216 790 A1 provides a method for assessing an effect of an object in the surroundings of a means of transportation on a driving maneuver of the means of transportation.
It is conventional in the related art that the position of recognized objects, for example the position of a pedestrian, may be estimated based on at least one camera image, for example a base point determination of the object taking place. However, this position estimation for pedestrians does not function, for example, when the objects are in the immediate vicinity of a vehicle camera, since the objects can then no longer be completely captured in the camera image. In park pilot systems, multiple vehicle cameras including wide-angle lenses may be used, and a surround view or a top-down view for the driver may be displayed with the aid of a display device. In principle, these wide-angle cameras are better suited for recognizing nearby objects; however, the camera-based position estimation may fail for objects in the close range of the vehicle.
The Kalman filter is used for the iterative estimation of state parameters of a system based on erroneous measurements, the errors of the measurements being reduced. The use for evaluating radar signals or GNSS data for position determination of moving objects, is conventional. There is a problem of the association of measurements with a track of the moving object. This means that when incorrect measurements are associated with a track of the object, this results in a relatively large error in the determined position and further evaluations. For example, in a typical park pilot system it is often not possible to distinguish between pedestrians and neighboring curbs, as the result of which the position determination and movement estimation for a pedestrian become imprecise.
An object of the present invention is to improve an ascertainment of an object position of a dynamic object in the surroundings of a vehicle, in particular with regard to continuous tracking of a pedestrian as a dynamic object, or tracking of the pedestrian in the close range of the vehicle.
The above object is achieved according to features of the present invention.
The present invention relates to a method for ascertaining an approximately actual object position or approximate object position of a dynamic object in the surroundings of a vehicle. The vehicle includes at least two ultrasonic sensors and at least one vehicle camera. According to an example embodiment of the present invention, the method includes a detection of sensor data with the aid of the at least two ultrasonic sensors of the vehicle. The detection of the sensor data takes place in particular continuously. The sensor data represent in particular at least one detected echo signal for an emitted ultrasonic signal between the vehicle and an object in the surroundings of the vehicle, and preferably a distance between the vehicle and the object, and optionally at least one property of the received echo signal. The property of the detected echo signal is based in particular on an evaluation of the detected echo signal, and advantageously represents a likelihood of the presence of a dynamic object. The evaluation of the echo signal for determining a likelihood of the presence of a dynamic object is a preferred optional method step. A present reflection origin position of a static or dynamic object is subsequently ascertained at least as a function of the detected sensor data of the at least two ultrasonic sensors of the vehicle, in particular using a trilateration method. The ascertainment of the present reflection origin position takes place in particular continuously, based on the presently detected sensor data of the at least two ultrasonic sensors of the vehicle. At least one camera image is detected in a further method step with the aid of the vehicle camera; in particular, a continuous detection of a camera image takes place with the aid of the vehicle camera. Accordingly, a sequence of camera images is preferably detected with the aid of the vehicle camera. The dynamic object is subsequently recognized by at least one (first) trained machine recognition method as a function of the at least one detected camera image, the trained machine recognition method preferably being a trained neural network. For example, the recognized dynamic object is another moving or nonmoving vehicle, a standing or walking pedestrian, a cyclist, or an animal, for example a dog or a cat. An ascertainment of a present estimated position of the recognized object relative to the vehicle subsequently takes place as a function of the at least one detected camera image. It may be provided that this estimated position is additionally ascertained with the aid of a motion equation, for example when a pedestrian can no longer be recognized as a dynamic object in the present image, since the pedestrian at least partially obscures the image. Alternatively or additionally, the ascertained present estimated position may be determined by a base point ascertainment or by some other trained machine recognition method, in particular a trained neural network, and/or as a function of a motion estimation of the recognized object. The present estimated position changes in particular continuously over time, since the dynamic object is movable. The motion estimation of the recognized object may advantageously take place based on a change in a size of an object box for the recognized object and a base point determination of the recognized object in consecutively detected camera images. If it is recognized in a subsequent method step that a position distance between the present estimated position of the recognized dynamic object in the surroundings of the vehicle, in particular relative to the vehicle, and the present reflection origin position is less than or equal to a distance threshold value, the present reflection origin position is classified, as a function of the underlying sensor data for ascertaining the present reflection origin position and/or in particular as a function of the at least one property of the echo signal, as belonging to the recognized dynamic object, it being optionally possible for this property of the echo signal to be ascertained as a function of the sensor data or of the echo signal. The classification preferably takes place as a function of an amplitude of the underlying detected echo signal of the sensor data and/or as a function of a correlation coefficient between the detected echo signal and the emitted ultrasonic signal as the particular property of the detected echo signal of the detected sensor data. The sensor data may include or represent this property when a processing unit of the ultrasonic sensor has ascertained the property as a function of the echo signal and in particular of the emitted ultrasonic signal, and this at least one ascertained property is provided in the sensor data. Alternatively or additionally, at least one property of the echo signal may be ascertained in the method as a function of the detected sensor data. It is preferably recognized, based on at least two properties of the echo signal, with the aid of a second trained machine recognition method, in particular a second neural network, whether or not the reflection origin position may be classified as belonging to the dynamic object. The approximate object position of the dynamic object is subsequently ascertained as a function of the reflection origin position classified as belonging to the dynamic object, in particular using a Kalman filter. This ascertainment of the approximate object position of the dynamic object is carried out in particular continuously. The present invention results in the advantage that in the close range of the vehicle, an accurate approximate object position of the dynamic object, recognized based on camera images, may be determined as a function of ultrasonic measurements. The ultrasonic sensors provide very accurate measured values in the close range of the vehicle, and in particular the camera images in the close range of the vehicle are in part evaluable only with difficulty. In addition, the assignment or association of the determined reflection origin positions to/with the dynamic objects is improved, since measured values for static objects, for example curb edges, plantings, posts, or the like are not taken into account. It is particularly advantageous that even approximate object positions of pedestrians that are situated close to the vehicle, i.e., at a distance of less than or equal to 2 meters, for example, may be determined very accurately, which is relevant for parking operations in parking facilities, for example, since this pedestrian position can no longer be accurately estimated based on cameras due to the fact that the camera image cannot completely capture the pedestrians, in particular the legs and feet.
In one optional embodiment of the present invention, the classification of the present reflection origin position as belonging to the recognized dynamic object additionally takes place as a function of the underlying sensor data of the reflection origin positions, classified as belonging to the recognized dynamic object, during a predefined time period prior to the present point in time in the surroundings of the present reflection origin position, the predefined time period being in a range of 10 milliseconds and 3 seconds, for example. In other words, in the classification it is taken into account whether the underlying sensor data for the reflection origin positions, classified as belonging to the recognized dynamic object, in the surroundings of the present reflection origin position indicate a likelihood of the present reflection origin position belonging to the dynamic object. This classification may advantageously take place via a further trained machine recognition method. Alternatively or additionally, the present reflection origin position may be assigned in particular to the reflection origin positions previously classified as belonging to the recognized dynamic object, based on a similar property of the echo signal of the sensor data. Alternatively or additionally, the present reflection origin position may be classified or not classified as belonging to the recognized dynamic object in particular based on a plausibility of the temporally changed position of the reflection origin positions previously classified as belonging to the recognized dynamic object. Since the information of the ascertained reflection origin positions from the surroundings, classified as belonging to the dynamic object, is taken into account for the ascertained present reflection origin position, the advantage results that the present reflection origin position may be more accurately classified as belonging to the recognized dynamic object. In particular, present reflection origin positions ascertained in this embodiment may be classified in an enhanced manner as belonging to static objects or other dynamic objects, i.e., classified as not belonging to the recognized dynamic object. As a result of the embodiment, the association of the reflection origin position with the dynamic object thus takes place more reliably, as the result of which the ascertainment of the approximate object position of the dynamic object becomes more accurate.
In one refinement of the above-described optional embodiment of the present invention, the surroundings of the present reflection origin position include those reflection origin positions, assigned to the dynamic object or classified as belonging to the dynamic object, whose distance from the present reflection origin position is less than or equal to a distance threshold value. This distance threshold value is adapted in particular as a function of a speed of the vehicle. According to an example embodiment of the present invention, alternatively or additionally, the surroundings of the present reflection origin position include at least one ultrasonic cluster that is assigned to the dynamic object, the ultrasonic cluster in particular including reflection origin positions classified as belonging to the dynamic object and/or including an extension and/or having a predefined geometric shape. Alternatively or additionally, the surroundings of the present reflection origin position include at least one grid cell of a grid of the present reflection origin position, the grid subdividing the surroundings of the vehicle. By use of these types of surroundings descriptions of the present reflection origin position, the advantage results that reflection origin positions classified as belonging to the dynamic object are further filtered, so that, for example, various dynamic objects of the same class, for example different pedestrians, may be more easily separated from one another, as the result of which the ascertainment of the approximate object position of the individual dynamic object becomes more accurate.
In another optional refinement of the present invention, a present object speed of the dynamic object and/or of a present object movement direction of the dynamic object are/is ascertained as a function of the ascertained approximate object positions of the dynamic object at different points in time. In this refinement, the advantage results that the ascertainment of the object speed and/or of the object movement direction takes place accurately, since the approximate object positions are accurately ascertained.
In a further optional embodiment of the present invention, the ascertainment of the approximate object position of the dynamic object and/or the ascertainment of the present object speed and/or of the present object movement direction of the dynamic object in each case are/is not carried out if the number of reflection origin positions classified as belonging to the dynamic object falls below a predefined confidence number. In this optional embodiment, greater reliability of the ascertained approximate object position, of the ascertained object speed, and of the ascertained object movement direction is achieved.
In addition, according to an example embodiment of the present invention, it may be provided that a determination of a statistical uncertainty is carried out as a function of the detected sensor data and/or of the ascertained present reflection origin position and/or of the reflection origin positions classified as belonging to the dynamic object and/or of the ascertained approximate object position. The distance threshold value is subsequently adapted as a function of the determined statistical uncertainty. In this optional embodiment, the reliability and the accuracy of the ascertained approximate object position, of the ascertained object speed, and of the ascertained object movement direction are increased.
The distance threshold value is preferably in a range between meter and 5 meters, and in particular the distance threshold value is 0.5 meter, 1 meter, 1.5 meters, or 3 meters. This results in the advantage that reflection origin positions that represent a different dynamic object in the surroundings of the vehicle are not erroneously classified by the method or the algorithm as belonging to the recognized dynamic object, or multiple dynamic objects may be separated from one another.
The distance threshold value is optionally adapted as a function of the vehicle speed. This results in the advantage that an increasing inaccuracy in the ascertainment of the present estimated position of the recognized object is taken into account with increasing vehicle speed, so that a more reliable classification of the reflection origin positions as belonging to the recognized dynamic object takes place at higher vehicle speeds, so that the ascertainment of the approximate object position of the dynamic object takes place more exactly as a function of the reflection origin positions classified as belonging to the dynamic object.
In another optional embodiment of the present invention, a normalization of at least a portion of the underlying sensor data for ascertaining the present reflection origin position with regard to their amplitude may be carried out in an additional method step, based on an angular position of the ascertained present reflection origin position for the detection range of the ultrasonic sensor. In this embodiment, the classification of the present reflection origin position as belonging to the recognized dynamic object takes place as a function of the normalized underlying sensor data and as a function of an amplitude threshold value, those reflection origin positions having a normalized amplitude less than or equal to the amplitude threshold value preferably being classified as belonging to the recognized dynamic object. The particular present reflection origin position is reliably classified by use of this embodiment.
Optionally, it may be further provided that a correlation coefficient between at least a portion of the detected sensor data underlying the reflection origin position and the sensor signal emitted by the ultrasonic sensor is additionally ascertained. In this embodiment, the classification of the present reflection origin position as belonging to the recognized dynamic object takes place as a function of the ascertained correlation coefficient and as a function of a correlation threshold value, those reflection origin positions having a correlation coefficient less than or equal to the correlation threshold value preferably being classified as belonging to the recognized dynamic object. As a result of this embodiment, the particular present reflection origin position is classified more reliably as belonging to the dynamic object, in particular when the classification is additionally carried out as a function of the normalized underlying sensor data and as a function of an amplitude threshold value.
In another optional embodiment of the present invention, the number of reflections for a sensor signal that is emitted by the ultrasonic sensor is ascertained as a function of at least a portion of the detected sensor data underlying the present reflection origin position. The classification of the present reflection origin position as belonging to the recognized dynamic object is subsequently carried out as a function of the ascertained number of reflections and as a function of a number threshold value, those reflection origin positions whose number of reflections is less than or equal to the number threshold value being classified as belonging to the recognized dynamic object. As a result of this embodiment, the particular present reflection origin position is classified very reliably as belonging to the dynamic object, in particular when the classification is additionally carried out as a function of the normalized underlying sensor data and as a function of an amplitude threshold value, and/or in particular when the classification additionally takes place as a function of the ascertained correlation coefficient and as a function of a correlation threshold value.
In one optional embodiment of the present invention, it may preferably be provided that the classification of the present reflection origin position as belonging to the recognized dynamic object takes place via a second trained machine recognition method.
Moreover, the present invention relates to a computer program that includes commands which, when the program is executed by a computer, prompt the computer to carry out the steps of the method(s) of the present invention disclosed herein.
Furthermore, the present invention relates to a device or a central processing unit or a zonal processing unit or a control unit for a vehicle. The central processing unit, the zonal processing unit, or the control unit include at least one first signal input that is configured to provide at least one first signal that represents detected sensor data of at least one ultrasonic sensor of the vehicle. The device also includes a second signal input that is configured to provide a second signal that represents detected camera images of a vehicle camera. A processing unit of the device, in particular a processor, is configured in such a way that it carries out the steps of the method according to the present invention.
In addition, the device includes an optional signal output, the signal output being configured to generate a control signal for a display device, a braking device, a steering device, and/or a drive motor as a function of the method carried out by the processing unit.
Moreover, the present invention relates to a vehicle that includes the device according to the present invention or the central processing unit according to the present invention or the zonal processing unit according to the present invention or the control unit according to the present invention.
Further advantages result from the following description of exemplary embodiments, with reference to the figures.
Classification 270 of the particular reflection origin positions as a function of the properties of the underlying echo signals, shown in
Number | Date | Country | Kind |
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10 2022 206 123.3 | Jun 2022 | DE | national |