DE102024103807A1 - Method for operating a detection device which is at least temporarily set to use electromagnetic signals with different polarization directions - Google Patents

Abstract

A method for operating a detection device (14), in particular a detection device (14) of a vehicle, a detection device (14), a driver assistance system (12), and a vehicle are described. In the method, at least one electromagnetic signal (26) is transmitted into a monitoring area (18) using the detection device (14). The at least one electromagnetic signal (30), which may be reflected in the monitoring area (18), is received by the detection device (14) and converted into at least one received variable (32) that can be processed using suitable evaluation means (34). The detection device (14) is at least temporarily set to use distinguishable electromagnetic signals (26, 30) with at least two different, defined polarization directions (H, V).

Description

Technical area

The invention relates to a method for operating a detection device, in particular a detection device of a vehicle, in which
the detection device sends at least one electromagnetic signal into a monitoring area
and the detection device receives at least one electromagnetic signal that may be reflected in the monitoring area and converts it into at least one received variable that can be processed by suitable evaluation means,
wherein the detection device is at least temporarily set to use electromagnetic signals with at least one defined polarization direction.

Furthermore, the invention relates to a detection device, in particular a detection device for a vehicle, which has at least some of the means for transmitting electromagnetic signals into a monitoring area, for receiving electromagnetic signals reflected in the monitoring area and for converting the received electromagnetic signals into received variables that can be processed with suitable evaluation means, and for at least temporarily setting the detection device to use electromagnetic signals with defined polarization directions.

Furthermore, the invention relates to a driver assistance system with at least one control unit and with at least one detection device for monitoring at least one monitoring area, wherein the driver assistance system has at least some of the means for transmitting electromagnetic signals into a monitoring area, for receiving electromagnetic signals reflected in the monitoring area and for converting the received electromagnetic signals into received variables that can be processed with suitable evaluation means, and for at least temporarily setting the use of electromagnetic signals with defined polarization directions.

Furthermore, the invention relates to a vehicle with at least one detection device for monitoring at least one monitoring area, wherein the vehicle has at least some of the means for transmitting electromagnetic signals into a monitoring area, for receiving electromagnetic signals reflected in the monitoring area and for converting the received electromagnetic signals into received variables that can be processed with suitable evaluation means, and for at least temporarily setting the use of electromagnetic signals with defined polarization directions.

State of the art

From the US 2020/0150241 A LiDAR system is known. The LiDAR system has a field of view. The LiDAR system includes one or more polarization-based waveguide splitters. The LiDAR system includes a polarization rotator optically coupled between the polarization-based waveguide splitter and an optical switching network. The polarization rotator can be configured to control the polarization of the light emitted by the sequence of optical emitters.

The invention is based on the object of designing a method, a detection device, a driver assistance system and a vehicle of the type mentioned at the outset, in which the detection of the surveillance area, in particular the accuracy of detection of objects in the surveillance area, can be improved.

Disclosure of the invention

The object is achieved according to the invention in the method in that the detection device is at least temporarily set to use distinguishable electromagnetic signals with at least two different defined polarization directions.

According to the invention, electromagnetic signals with at least two different polarizations are used. The electromagnetic signals can be transmitted with different polarization directions. Alternatively or additionally, electromagnetic signals with different polarization directions can be received. The use of electromagnetic signals within the meaning of the invention implies the transmission, reception, and conversion of electromagnetic signals.

If an object target is hit by an electromagnetic signal, the intensity of the reflected electromagnetic signal depends on the polarization direction of the electromagnetic signal on the one hand and the surface normal of the surface of the object target hit by the electromagnetic signal on the other. From the intensity of the reflected electromagnetic signal received by the detection device, the orientation of the Surface normal of the object target at which the electromagnetic signal was reflected is closed in space.

By using at least two distinguishable electromagnetic signals with at least two different, defined polarization directions, the accuracy of detecting targets can be improved without having to increase the spatial resolution and thus the number of receiving elements of the detection device, such as pixels. The receiving elements of the detection device can advantageously be formed as pixels of a line detector or area detector, for example, an imager chip, a CCD chip, or the like.

With the invention, the accuracy in the detection of object targets can be increased without having to reduce the aperture angle, in particular the vertical and/or horizontal aperture angle, of the detection elements. Since no reduction in the aperture angle is required, it is also unnecessary to reduce the frame rate of the receiving device of the detection apparatus, in particular an image sensor or the like, or to use a receiving device with a larger number of receiving elements. Thus, with the aid of the invention, existing detection devices can be more easily expanded to include the function for determining the orientation of detected objects in space.

According to the invention, the detection device determines the intensities of received electromagnetic signals. Depending on the intensities, respective received variables are determined. The received variables can be processed using the detection device.

By using at least two different defined polarization directions, information on the orientation of the detected object target, in particular the orientation of the surface normal, in space can also be determined from the determined reception variables.

As is well known, the polarization direction of an electromagnetic wave is the oscillation direction of the electric or magnetic field. For the purposes of the invention, the oscillation direction of the electric field or the oscillation direction of the magnetic field can be used to define the polarization direction.

The invention can be used in vehicles. An essential functional feature of a vehicle is its ability to move. Vehicles can be motor vehicles. The invention can advantageously be used in land vehicles, in particular cars, trucks, buses, motorcycles, drones, mobile robots, mobile machines, in particular construction or transport machines such as cranes, excavators, or the like, aircraft, in particular aerial drones, and/or (underwater) vehicles, in particular (underwater) drones. The invention can also be used in vehicles that can be operated autonomously or semi-autonomously. However, the invention is not limited to vehicles. It can also be used in stationary operation.

The detection device can be used to detect stationary or moving objects, in particular vehicles, persons, animals, plants, obstacles, ground, roadways, road surface irregularities, in particular potholes or stones, road boundaries, (road) markings, (traffic) signs, open spaces, in particular parking spaces, precipitation or the like, and/or movements and/or gestures.

An object target, as defined by the invention, is a location on an object where electromagnetic signals can be reflected. An object typically has a plurality of object targets.

With an advantageous design of the procedure,
at least two electromagnetic signals are sent one after the other, in particular not superimposed
and/or
at least two electromagnetic signals are transmitted superimposed in time, in particular simultaneously.

Advantageously, at least two electromagnetic signals can be transmitted sequentially, in particular without overlapping. This makes it easier to distinguish between the electromagnetic signals. Advantageously, the at least two electromagnetic signals can be transmitted without overlapping. This also prevents mutual interference between the electromagnetic signals on the receiving side.

Alternatively or additionally, at least two electromagnetic signals can be transmitted in a temporally superimposed manner, particularly simultaneously. This can reduce the overall measurement time.

In a further advantageous embodiment of the method, at least two with respect to their shape, in particular with respect to their waves Distinguishable electromagnetic signals can be transmitted based on length, modulation frequency, coding, or the like. In this way, even signals transmitted simultaneously or overlapping in time can be distinguished.

In a further advantageous embodiment of the method, at least one orientation variable, in particular a direction of a surface normal, can be determined using the at least one received variable and taking into account the respective setting of the polarization direction, wherein the at least one orientation variable characterizes an orientation of at least one object target, in particular an orientation of the surface of at least one object target at which the at least one electromagnetic signal is reflected, relative to at least one reference system, in particular relative to a coordinate system. In this way, an influence of the reflecting object target on the reflected electromagnetic signals can be taken into account. This influence depends on the orientation of the surface of the at least one object target with respect to the polarization direction of the incident electromagnetic signals. The influence can be quantified via the intensity of the received reflected electromagnetic signals.

Advantageously, the detection device can transmit at least one electromagnetic signal into the monitored area in response to at least one transmitted variable. In this way, the transmission time can be precisely specified. Furthermore, the shape of the electromagnetic signal and/or the polarization direction can also be adjusted using the transmitted variable.

Advantageously, at least one orientation variable can be determined from at least one relationship between the at least one transmitted variable for a transmitted electromagnetic signal and the at least one received variable for the corresponding received reflected electromagnetic signal, taking into account the respective setting of the polarization direction. In this way, the transmitted variables and received variables can be directly related on the detection device side, in particular with the aid of an evaluation device. Thus, distances, directions, and/or speeds of detected object targets can be more easily determined, in particular calculated, based on the transmitted variables and received variables.

The transmit variables can be used to define the transmission times for the electromagnetic signals. Similarly, the receive variables can be used to define the reception times for the electromagnetic signals. This makes it easier to determine the time of flight between the transmission of an electromagnetic signal and the reception of the corresponding reflected electromagnetic signal. The flight time can be used to determine the relative distance of a detected target object.

Advantageously, the transmitted variables can be electrical signals. This allows them to be easily processed using electrical means, in particular electrical evaluation devices, control units, or the like. The transmitted variables can be used to specify the duration and intensity of the at least one transmitted electromagnetic signal. Furthermore, the transmitted variables can be used to specify a form, in particular a modulation frequency, wavelength, and/or coding, for the electromagnetic signal.

Advantageously, the received variables can be electrical signals. This allows them to be easily processed using electrical means, in particular electrical evaluation devices, control units, or the like.

Advantageously, the detection device can comprise means for converting transmitted variables, in particular electrical transmitted variables, into electromagnetic signals and/or means for converting electromagnetic signals into received variables, in particular electrical received variables. In this way, transmitted variables and/or received variables, in particular of the same type, can be processed within the detection device, particularly electrically. Outside the detection device, the electromagnetic signals can propagate without contact and scan the monitored area accordingly.

Advantageously, the orientation of at least one target object relative to at least one reference system can be characterized. Advantageously, the reference system can be a coordinate system, in particular a vehicle coordinate system or a coordinate system of the detection device. In this way, the orientation can be clearly specified.

Advantageously, the polarization direction of the electromagnetic signals can be adjusted relative to the at least one reference system. In this way, the orientation of a detected object target can be more easily related to the polarization directions of the electromagnetic signals.

Advantageously, the at least one orientation variable can characterize an orientation of the surface of at least one detected object target. In this way, the external geometry of an object having multiple object targets can be determined. Advantageously, the orientation of the surface of at least one detected object target can be specified by the direction of a surface normal. The direction of the surface normal can be specified as an orientation variable.

In a further advantageous embodiment of the method, at least one property, in particular an orientation and/or a type and/or class, of at least one detected object with multiple object targets can be determined using at least one orientation variable. In this way, additional information about objects in the surveillance area can be determined. Information about the type, class, and orientation of objects in the surveillance area is particularly important for the function of a driver assistance system. This allows the environment in which the vehicle with the at least one detection device is located to be determined more precisely. Precise knowledge of the environment is required for autonomous or semi-autonomous operation of the vehicle.

In a further advantageous embodiment of the method,
the detection device can be set at least temporarily to transmit electromagnetic signals with at least two different defined polarization directions
and/or
the detection device can be set at least temporarily to receive electromagnetic signals with at least two different defined polarization directions.

Advantageously, the detection device can be configured, at least temporarily, to transmit electromagnetic signals with different polarization directions. This eliminates the need to use different polarization directions on the receiving side of the detection device. Furthermore, on the transmitting side of the detection device, the polarization direction can be specified with respect to a reference system, in particular with respect to a coordinate system.

Alternatively or additionally, the detection device can advantageously be set, at least temporarily, to receive electromagnetic signals with at least two different polarization directions. In this way, the setting of different polarization directions on the transmitting side of the detection device can be omitted.

Advantageously, different polarization directions can be set on both the transmitting and receiving sides of the detection device. This can improve the measurement accuracy of the detection device.

In a further advantageous embodiment of the method,
the detection device can be switched at least temporarily between at least two transmission sequences for transmitting electromagnetic signals with at least two different defined polarization directions and set to receive electromagnetic signals with the at least two polarization directions of the transmitted electromagnetic signals and not switched between the at least two transmission sequences
and/or
the detection device is not switched at least temporarily between at least two transmission sequences for transmitting electromagnetic signals with respect to the polarization direction and is switched between the at least two transmission sequences for receiving electromagnetic signals with at least two different defined polarization directions
and/or
the detection device can be switched at least temporarily between at least two transmission sequences both for transmitting electromagnetic signals and for receiving electromagnetic signals, each with at least two different defined polarization directions.

Advantageously, the detection device can be switched between at least two different defined polarization directions only on the transmitting side between at least two transmission sequences. This eliminates the need to switch the polarization direction on the receiving side.

Alternatively or additionally, the detection device can be switched between at least two different defined polarization directions between at least two transmission sequences only on the receiving side. In this way, switching the polarization direction on the transmitting side can be omitted.

Alternatively or additionally, the detection device can at least temporarily switch between at least two transmission sequences on both the transmitting side and the receiving side between at least two different defined The polarization direction can be changed. This can improve the overall measurement accuracy of the detection device.

In a transmission sequence, at least one electromagnetic signal can be transmitted into the surveillance area. Electromagnetic signals reflected by at least one potential target object in the surveillance area can be received on the receiving side by the detection device and assigned to the respective transmitted electromagnetic signals. A transmission sequence can be defined by a time duration and/or a number of transmitted electromagnetic signals. A transmission sequence can also be referred to as a measurement sequence, in which distance measurements, direction measurements, and/or speed measurements are performed for object targets.

In one transmission sequence, several different or distinguishable electromagnetic signals can be sent.

To monitor a surveillance area, multiple transmission sequences can be performed consecutively. The transmission sequences can be performed continuously. In this way, the surveillance area can be monitored continuously.

In a further advantageous embodiment of the method,
the detection device can be set to use electromagnetic signals with two orthogonal polarization directions
and/or
the detection device can be set to use electromagnetic signals with a horizontal polarization direction and a vertical polarization direction
and/or
The detection device can be configured to use electromagnetic signals with two orthogonal polarization directions aligned along the axes of a three-dimensional vehicle coordinate system. This allows the orientation of an object target, from which the electromagnetic signals are reflected, to be unambiguously determined using only two different polarization directions.

Advantageously, the at least two polarization directions can be oriented to a spatial reference system. In this way, the polarization directions can be unambiguously assigned.

Advantageously, a horizontal polarization direction and a spatially vertical polarization direction can be used. In this way, the orientations of the detected targets can be directly determined from the relationships between the transmitted and corresponding received variables.

Especially when using the detection device on a vehicle, the spatial vertical and horizontal orientation are of great importance. In particular, road surfaces, which generally have a spatial horizontal orientation, can be distinguished from obstacles, which generally have a spatial vertical orientation.

Advantageously, the detection device can be configured to use electromagnetic signals with two orthogonal polarization directions aligned with the axes of a three-dimensional vehicle coordinate system. This allows the orientations of detected target objects to be unambiguously assigned to the vehicle coordinate system.

Advantageously, at least one of the two orthogonal polarization directions can run parallel to a vehicle's vertical axis. This polarization direction can be defined as the vertical polarization direction. The second of the two orthogonal polarization directions can run parallel to a vehicle's transverse axis. This polarization direction can be defined as the horizontal polarization direction.

In a further advantageous embodiment of the method, the method can be used to operate a detection device configured as a LiDAR system or radar system. Such LiDAR systems and radar systems each use electromagnetic signals to detect objects. With LiDAR systems, objects can be detected using electromagnetic signals in the form of light signals, in particular light pulses such as laser pulses. With radar systems, objects can be detected using electromagnetic signals in the form of radar signals, in particular radar chirps.

LiDAR and radar systems can be used to determine the distances, directions, and/or speeds of detected objects relative to a corresponding reference system, in particular relative to the corresponding detection device. Furthermore, data acquired with LiDAR and radar systems can be used to determine information about the surveillance area, in particular about objects within the surveillance area, such as object classifications.

Advantageously, the detection device can operate according to a signal-time-of-flight method, in particular a signal-pulse-time-of-flight method. Detection devices operating according to the signal-time-of-flight method can be designed and referred to as a time-of-flight (TOF) system, an indirect time-of-flight (iTOF) system, a light detection and ranging (LiDAR) system, a laser detection and ranging (LaDAR) system, a radar system, or the like.

Advantageously, the detection device can be configured as a laser-based distance measuring system. Laser-based distance measuring systems can have lasers, in particular diode lasers, as signal sources. Lasers can, in particular, transmit pulsed laser beams as electromagnetic signals. Accordingly, receivers of the detection device can comprise or consist of detectors designed for the wavelength of the emitted electromagnetic signals, in particular point sensors, line sensors, and/or area sensors, in particular (avalanche) photodiodes, photodiode arrays, CCD sensors, active pixel sensors, in particular CMOS sensors, or the like.

Furthermore, the object is achieved according to the invention in the detection device in that the detection device has at least some of the means for carrying out the method according to the invention.

Advantageously, the means for carrying out the method according to the invention can comprise means, in particular at least one transmitting device, for transmitting electromagnetic signals. Furthermore, the means for carrying out the method according to the invention can comprise means, in particular at least one receiving device, for receiving electromagnetic signals and for converting the received electromagnetic signals into received variables. Furthermore, the means for carrying out the method according to the invention can comprise means, in particular at least one control and/or evaluation device, for at least temporarily adjusting the detection device to use electromagnetic signals with defined polarization directions.

Advantageously, the means for carrying out the method according to the invention can comprise means for setting the at least temporary use of distinguishable electromagnetic signals with at least two different defined polarization directions.

The means for adjusting the use of electromagnetic signals with defined polarization directions may comprise optical, electro-optical or electromagnetic components such as filters, gratings, antennas, waveguides or the like.

Advantageously, the detection device can be designed for use with a vehicle. The detection device can be used to monitor at least one monitoring area in the surroundings of the vehicle and/or within the vehicle, in particular for objects.

Furthermore, the object is achieved according to the invention in the driver assistance system in that the driver assistance system has at least some means for carrying out the method according to the invention.

The driver assistance system has at least one detection device. The at least one detection device can be used to monitor at least one monitoring area in the surroundings of the vehicle and/or in the interior of the vehicle for objects. The detection device can be used to determine the distances, directions, and/or speeds of detected objects.

The driver assistance system has at least some of the means for carrying out the method according to the invention. Advantageously, at least one detection device of the driver assistance system can have at least some of the means for carrying out the method according to the invention. Since the at least one detection device is part of the driver assistance system, the part of the means of the at least one detection device for carrying out the method according to the invention is also part of the driver assistance system, i.e., also part of the means of the driver assistance system. Advantageously, at least some of the means for carrying out the method according to the invention can be implemented exclusively with the at least one detection device. Alternatively, at least some of the means for carrying out the method according to the invention can be implemented with the driver assistance system but separately from the at least one detection device. Alternatively, at least some of the means for carrying out the method according to the invention can be implemented with the at least one detection device, and some of the means for carrying out the method according to the invention with the driver assistance system can be implemented separately from the at least one detection device. The same applies to the vehicle of which the at least one detection device and/or the driver assistance system are a part. Accordingly, the means of the at least one detection device tion device and/or the driver assistance system are also part of the vehicle's resources.

Furthermore, the object is achieved according to the invention in the vehicle in that the vehicle has at least some of the means for carrying out the method according to the invention.

The vehicle has at least one detection device. With the at least one detection device, at least one monitoring area in the surroundings of the vehicle and/or within the vehicle can be monitored, in particular for objects.

Advantageously, the vehicle may have at least one driver assistance system.

With at least one driver assistance system, functions, in particular driving functions, of the vehicle can be carried out autonomously or semi-autonomously.

Advantageously, the at least one detection device can be part of at least one driver assistance system or connected to at least one driver assistance system. In this way, information obtained with the at least one detection device can be used for the autonomous or semi-autonomous operation of the functions, in particular the driving functions, of the vehicle.

Furthermore, the features and advantages presented in connection with the method according to the invention, the detection device according to the invention, the driver assistance system according to the invention, and the vehicle according to the invention, and their respective advantageous embodiments, apply to one another accordingly and vice versa. The individual features and advantages can, of course, be combined with one another, whereby further advantageous effects can arise that go beyond the sum of the individual effects.

Short description of the drawings

• 1 eine Seitenansicht eines Fahrzeugs mit einem Fahrerassistenzsystem, welches ein LiDAR-System und eine Steuereinheit aufweist, wobei sich im Überwachungsbereich des LiDAR-Systems ein Objekt befindet;
• 2 eine Draufsicht des Fahrzeugs mit dem Objekt aus der 1;
• 3 eine Funktionsdarstellung des Fahrerassistenzsystems des Fahrzeugs aus den 1 und 2;
• 4 der zeitliche Verlauf von Einstellungen von Polarisationsmodi beim Betrieb des LiDAR-Systems aus den 1 und 3 gemäß einem ersten Ausführungsbeispiel;
• 5 der zeitliche Verlauf von Einstellungen von Polarisationsmodi beim Betrieb des LiDAR-Systems aus den 1 und 3 gemäß einem zweiten Ausführungsbeispiel;
• 6 der zeitliche Verlauf von Einstellungen von Polarisationsmodi beim Betrieb des LiDAR-Systems aus den 1 und 3 gemäß einem dritten Ausführungsbeispiel;
• 7 der zeitliche Verlauf von Einstellungen von Polarisationsmodi beim Betrieb des LiDAR-Systems aus den 1 und 3 gemäß einem vierten Ausführungsbeispiel;
• 8 der zeitliche Verlauf von Einstellungen von Polarisationsmodi beim Betrieb des LiDAR-Systems aus den 1 und 3 gemäß einem fünften Ausführungsbeispiel.

Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are explained in more detail with reference to the drawings. Those skilled in the art will expediently consider the features disclosed in the drawings, the description, and the claims in combination individually and combine them to form useful further combinations. The figures show schematically:

• 1 a side view of a vehicle with a driver assistance system having a LiDAR system and a control unit, wherein an object is located in the monitoring area of the LiDAR system;
• 2 a top view of the vehicle with the object from the 1 ;
• 3 a functional representation of the vehicle’s driver assistance system from the 1 and 2 ;
• 4 the temporal progression of polarization mode settings during operation of the LiDAR system from the 1 and 3 according to a first embodiment;
• 5 the temporal progression of polarization mode settings during operation of the LiDAR system from the 1 and 3 according to a second embodiment;
• 6 the temporal progression of polarization mode settings during operation of the LiDAR system from the 1 and 3 according to a third embodiment;
• 7 the temporal progression of polarization mode settings during operation of the LiDAR system from the 1 and 3 according to a fourth embodiment;
• 8 the temporal progression of polarization mode settings during operation of the LiDAR system from the 1 and 3 according to a fifth embodiment.

In the figures, identical components are provided with identical reference symbols.

Embodiment(s) of the invention

In 1 a vehicle 10 in the form of a passenger car is shown in side view. 2 shows the vehicle 10 in a top view.

The vehicle 10 has a driver assistance system 12. The driver assistance system 12 includes a detection device in the form of a LiDAR system 14 and a control unit 16.

The LiDAR system 14 can capture a surveillance area 18. The LiDAR system 14 is located, for example, at the front of the vehicle 10 in the direction of travel and is aligned in the direction of travel. The surveillance area 18 is located in front of the vehicle 10 in the direction of travel.

The LiDAR system 14 can also be arranged at a different location and with a different orientation on the vehicle 10. Multiple LiDAR systems 14 can also be arranged on the vehicle 10—even at different locations and with different orientations.

The LiDAR system 14 is connected to the control unit 16 for data transmission. Data obtained with the LiDAR system 14, for example, about the surveillance area 18, can be transmitted to the control unit 16 via the connection. The control unit 16 can execute functions, in particular driving functions, of the vehicle 10 autonomously or semi-autonomously.

Furthermore, control signals can be transmitted from the control unit 16 to the LiDAR system 14 via the connection. With the LiDAR system 14, objects 20 located in the monitoring area 18 can be detected without contact. 1 to 3 For example, an object 20 is indicated in the form of a sidewalk.

The LiDAR system 14 can be used to detect stationary or moving objects 20, in particular vehicles, persons, animals, plants, obstacles, ground, roadways, road surface irregularities, in particular potholes or stones, road boundaries, (road) markings, (traffic) signs, open spaces, in particular parking spaces, precipitation or the like, and/or movements and/or gestures and/or lost cargo/goods.

Furthermore, in the 1 to 3 For easier orientation, the respective axes of an orthogonal vehicle coordinate system 22 are shown. The x-axis of the vehicle coordinate system 22 runs parallel to a transverse axis of the vehicle 10, for example. The y-axis runs parallel to the vehicle's longitudinal axis. The z-axis runs parallel to the vehicle's vertical axis. If the vehicle 10, as shown in the 1 and 2 As shown, the vehicle is located on a spatially horizontal roadway 24, the z-axis of the vehicle coordinate system 22 runs spatially vertically. The x-axis and the y-axis run spatially horizontally.

The LiDAR system 14 can transmit electromagnetic signals 26 into the surveillance area 18. The electromagnetic signals 26 can be reflected by targets 28 of objects 20 located in the surveillance area 18.

An object target 28 is a location on an object 20 at which the electromagnetic signals 26 can be reflected. Each object 20 typically has a plurality of object targets 28. In the 1 to 3 For the sake of clarity, only one of the object targets 28 of object 20 is indicated with a black dot.

Electromagnetic signals 26 reflected from a target object 28 toward the LiDAR system 14 are referred to as electromagnetic echo signals 30 for ease of differentiation. Electromagnetic echo signals 30 can be received by the LiDAR system 14.

The received echo signals 30 can be converted into received variables 32 using means of the LiDAR system 14. The received variables 32 can be electrical variables, for example. The received variables 32 can be processed using an electrical control and evaluation device 34 of the LiDAR system 14.

Each surface of an object 20 has at least one surface normal 36. The surface normal 36 extends perpendicular to the surface of the object 20. The direction of a surface normal 36 characterizes the orientation of the surface and thus of the object 20. If the surface is flat, one surface normal 36 is sufficient to describe the orientation of the surface. For curved surfaces, multiple surface normals 36 may be required to describe the surface's contour. Each object target 28 of an object 20 can be assigned a surface normal 36.

In the 1 to 3 , two of the surface normals 36 of the object 20 there are shown as examples. In the example object 20 shown, the upper side, which forms the sidewalk, is, for example, flat and spatially horizontal, i.e., parallel to the xy-plane of the vehicle coordinate system 22. The surface normal 36 of the horizontally running upper side of the object 20 extends spatially vertically, parallel to the z-axis. The side surfaces of the object 20, which form curbs, for example, are flat and spatially vertical. The side surface of the object 20 facing the vehicle 10 extends, for example, parallel to the xz-plane of the vehicle coordinate system 22. The surface normal 36 of the vertical surface facing the vehicle 10 extends spatially horizontally, for example parallel to the y-axis.

In the 3 a functional representation of the driver assistance system 12 with the LiDAR system 14 and the control unit 16 is shown.

The LiDAR system 14 comprises a transmitting device 38, a receiving device 40, and the control and evaluation device 34. The transmitting device 38 comprises means for generating electromagnetic signals 26. For example, the transmitting device 38 comprises laser diodes for generating electromagnetic signals 26 in the form of laser pulses.

Furthermore, the transmitting device 38 comprises means with which the polarization direction of the electromagnetic signals 26 transmitted into the monitoring area 18 can be adjusted. The polarization direction under consideration can, for example, be the oscillation direction of the electric field. Alternatively, instead of the oscillation direction of the electric field, the oscillation direction of the magnetic field can also be considered the polarization direction.

For example, the transmitting device 38 can be set to transmit electromagnetic signals 26 with vertical polarization direction V and to transmit electromagnetic signals 26 with horizontal polarization direction H.

The vertical polarization direction V is in the 3 to 8 Each is indicated by a vertical double arrow. The vertical polarization direction V runs, for example, parallel to the z-axis of the vehicle coordinate system 22, and in the usual operating orientation of the vehicle 10, approximately vertically. The horizontal polarization direction H is indicated by a circle with a cross. The horizontal polarization direction H runs, for example, parallel to the x-axis, and in the usual operating orientation of the vehicle 10, approximately horizontally.

The transmitting device 38 can be controlled by the control and evaluation device 34. For this purpose, electrical transmission variables 42 can be transmitted to the transmitting device 38 by the control and evaluation device 34. A polarization mode PMTx of the transmitting device 38 can also be set using the transmission variables 42. The setting of the polarization mode PMTx of the transmitting device 38 is described below in connection with the 4 to 8 explained in more detail.

The transmitting device 38 has, for example, two polarization modes PMTx, namely a horizontal polarization mode and a vertical polarization mode. In the vertical polarization mode PMTx, electromagnetic signals 26 are transmitted with a vertical polarization direction V. In the horizontal polarization mode PMTx, electromagnetic signals 26 are transmitted with a horizontal polarization direction H.

Furthermore, the transmitting device 38 has means for distinguishing the transmitted electromagnetic signals 26. For example, wavelengths, modulation frequencies, or coding of the signals 26 can be used for differentiation.

The receiving device 40 comprises, for example, a detector, for example in the form of an imager chip. The detector comprises a plurality of receiving elements, for example arranged in a planar manner, in the form of pixels. The pixels can receive electromagnetic echo signals 30. The detector can convert the received echo signals 30 into the electrical received quantities 32.

Furthermore, the receiving device 40 has means for setting the polarization direction for which the receiving device 40 is to be ready to receive. The receiving device 40 can be set to receive only echo signals 30 with a vertical polarization direction V, or to receive only echo signals 30 with a horizontal polarization direction H, or to receive echo signals 30 with both a vertical polarization direction V and echo signals 30 with a horizontal polarization direction H.

The receiving device 40 has, for example, two polarization modes PMRx, namely a horizontal polarization mode and a vertical polarization mode. In the vertical polarization mode PMRx, electromagnetic echo signals 30 with vertical polarization direction V are received. In the horizontal polarization mode PMRx, electromagnetic echo signals 30 with horizontal polarization direction H are received. The setting of the polarization mode PMRx of the receiving device 40 is described below in connection with the 4 to 8 explained in more detail.

In the vertical polarization mode PMRx of the receiving device 40, only echo signals 30 with a vertical polarization direction V can be received. In the horizontal polarization mode PMRx of the receiving device 40, only echo signals 30 with a horizontal polarization direction H can be received and converted. The vertical polarization mode PMRx and the horizontal polarization mode PMRx can also be set simultaneously, so that both echo signals 30 with a vertical polarization direction V and echo signals 30 with a horizontal polarization direction H can be received and converted.

Using the transmission variables 42 and the respective reception variables 32, the control and evaluation device 34 can determine distances, directions and speeds of detected object targets 28 in relation to the vehicle coordinate system 22, i.e. relative to the vehicle 10.

Furthermore, the control and evaluation device 34 has means with which, using the transmission variables 42 and the reception variables 32, taking into account the polarization modes PMTx and PMRx, i.e. the polarization directions H and/or V of the electromagnetic signals 26 and the received echo signals 30, the orientation of the surface normal 36 of the respectively detected object target 28 relative to the vehicle coordinate system 22, i.e. relative to the space, can be determined.

The relationship between the orientation of the surface of an object target 28, which is defined by the surface normal 36, and the polarization direction of the incident electromagnetic signal 26 is known to influence the intensity of the corresponding reflected echo signal 30. From the knowledge of the polarization direction of the electromagnetic signal 26 and the polarization direction of the corresponding received electromagnetic echo signal 30, the orientation of the surface of the object target 28, for example in the form of the direction of the surface normal 36, can be determined.

In addition, the control and evaluation device 34 has means with which the objects 20 to which the detected object targets 28 belong can be classified from the received variables 32, the transmitted variables 42, and, if applicable, the information about the orientations of the surface normals 36. For example, the information about the surface normals 36 can be used to classify the detected object 20 as another vehicle, a person, a roadway boundary, or another obstacle. Plants and precipitation can also be considered as objects 20.

The information about objects 20 in the monitoring area 18 determined by the LiDAR system 14 can be transmitted to the control unit 16 of the driver assistance system 12. Based on this information, the control unit 16 can execute the functions, in the case of driving functions, of the vehicle 10 autonomously or semi-autonomously.

In the 4 The temporal progression of the settings of the PMTx polarization mode of the transmitting device 38 and the PMRx polarization mode of the receiving device 40 according to a first exemplary embodiment is shown. In the first exemplary embodiment, transmission sequences 44 are performed sequentially. In each transmission sequence 44, electromagnetic signals 26 are transmitted, for example, and the corresponding electronic echo signal 30 is received.

The polarization mode PMTx of the transmitting device 38, in 4 above, is alternately set to transmit electromagnetic signals 26 with horizontal polarization direction H and to transmit electromagnetic signals 26 with vertical polarization direction V. Between the transmission sequences 44, the polarization direction of the transmitted electromagnetic signals 26 is changed. In each transmission sequence 44, an electromagnetic signal 26 with the corresponding polarization direction is transmitted. The polarization mode PMRx receiving device 40, in 4 below, is set in each transmission sequence 44 both to receive echo signals 30 with horizontal polarization direction H and to receive echo signals 30 with vertical polarization direction V.

In 5 The time course of the settings of the polarization mode PMTx of the transmitting device 38 and the polarization mode PMRx of the receiving device 40 according to a second embodiment is shown. In contrast to the first embodiment of 4 the polarization mode PMTx of the transmitting device 38 is set in all transmission sequences 44 for transmitting electromagnetic signals 26 with a horizontal polarization direction H. The polarization mode PMRx of the receiving device 40 is set alternately in the transmission sequences 44 for receiving echo signals 30 with a vertical polarization direction V and for receiving echo signals 30 with a horizontal polarization direction H.

In a not shown alternative to the second embodiment from 5 the transmitting device 38 can be set in all transmitting sequences 44 to transmit electromagnetic signals 26 with a vertical polarization direction V instead of transmitting electromagnetic signals 26 with a horizontal polarization direction H.

In the 6 The time course of the settings of the polarization mode PMTx of the transmitting device 38 and the polarization mode PMRx of the receiving device 40 according to a third embodiment is shown. In the third embodiment, in contrast to the second embodiment, 5 the polarization mode PMTx of the transmitting device 38 is set in all transmission sequences 40 for transmitting electromagnetic signals 26 with unpolarized electromagnetic signals 26. The setting of the polarization direction for the electromagnetic signals 26 is in the 6 Indicated above with stars. In the third exemplary embodiment, the PMRx polarization mode of the receiving device 40 is set in the transmission sequences 44, corresponding to the second exemplary embodiment, alternately for receiving echo signals 30 with a vertical polarization direction V and for receiving echo signals 30 with a horizontal polarization direction H.

In the 7 is the time course of the settings of the polarization mode PMTx of the Sen device 38 and the polarization mode PMRx of the receiving device 40 according to a fourth exemplary embodiment. In the fourth exemplary embodiment, both the position mode PMTx of the transmitting device 38 and the polarization mode PMRx of the receiving device 40 are switched between individual transmission sequences 44. By way of example, the polarization mode PMTx of the transmitting device 38 is set in the first two transmission sequences 44 to transmit electromagnetic signals 26 with a horizontal polarization direction H. In the 3rd and 4th transmission sequences 44, the polarization mode PMTx is switched to transmit electromagnetic signals 26 with a vertical polarization direction V. The polarization mode PMRx for the receiving device 44, on the other hand, is set for the first transmission sequence 44 to receive echo signals 30 with a horizontal polarization direction H. For the second and third transmission sequence 44, the PMRx polarization mode of the receiving device 40 is set to receive echo signals 30 with a vertical polarization direction V. For the fourth transmission sequence 44, the PMRx polarization mode of the receiving device 40 is switched to receive echo signals 30 with a horizontal polarization direction H.

In an alternative to the fourth embodiment (not shown), other setting schemes for the polarization mode PMTx of the transmitting device 38 and/or for the polarization mode PMRx of the receiving device 40 can also be selected.

In the 8 A time course of the setting of two polarization modes PMTx, namely PMTx1 and PMTx2, of the transmitting device 38 and the polarization mode PMRx of the receiving device 40 according to the fifth embodiment is shown. In contrast to the first embodiment from the 4 In each transmission sequence 44, two electromagnetic transmission signals 26 are transmitted simultaneously. The simultaneously transmitted electromagnetic transmission signals 26 can be distinguished. For example, the two simultaneously transmitted electromagnetic transmission signals 26 have different wavelengths and/or modulation frequencies and/or individual codings. In this way, the corresponding echo signals 30 can also be differentiated on the receiving device 40 side and assigned to the respective transmission signals 26. In each case, one of the signals 26 transmitted in the transmission sequences 44 is transmitted according to the polarization mode PMTx1 with a vertical polarization direction V. The respective other signal 26 of the transmission sequence 44 is transmitted according to the polarization mode PMTx2 with a horizontal polarization direction H. In each transmission sequence 44, the receiving device 40 is set to receive both echo signals 30 with a horizontal polarization direction H and echo signals 30 with a vertical polarization direction V. By means of appropriate distinguishing means, for example wavelength, modulation frequency and/or coding, the respective echo signals 30 can be distinguished and assigned to the corresponding signals 26.

In embodiments of the lidar system 14 not shown, the transmitting device 38 and/or the receiving device 40 can also only be used to transmit or receive the corresponding polarization directions according to the embodiments from the 4 to 8 For example, in the first embodiment shown in 4 and the fifth embodiment from 8 It is not necessary to switch the receiving device 40 between the horizontal polarization direction H and the vertical polarization direction V between transmission sequences 44, so that corresponding means for switching are not required. Only means are required with which the polarization mode PMRx of the receiving device 40 is set once for the respective polarization direction. In the second embodiment of 5 , in the third embodiment from 6 and in the fifth embodiment from 8 Means for changing the polarization direction of the transmitting device 38 between the transmission sequences 44 can be dispensed with. Only means are required with which the polarization mode PMTx of the transmitting device 38 is set once for the respective polarization direction.

QUOTES CONTAINED IN THE DESCRIPTION

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Cited patent literature

• US 2020/0150241 [0005]

Claims (12)

Method for operating a detection device (14), in particular a detection device (14) of a vehicle (10), in which at least one electromagnetic signal (26) is transmitted into a monitoring area (18) by means of the detection device (14), and the at least one electromagnetic signal (30) possibly reflected in the monitoring area (18) is received by the detection device (14) and converted into at least one received variable (32) which can be processed by suitable evaluation means (34), wherein the detection device (14) is at least temporarily set to use electromagnetic signals (26, 30) with at least one defined polarization direction (H, V), characterized in that the detection device (14) is at least temporarily set to use distinguishable electromagnetic signals (26, 30) with at least two different defined polarization directions (H, V). Procedure according to Claim 1 , characterized in that at least two electromagnetic signals (26) are transmitted one after the other, in particular not superimposed, and/or at least two electromagnetic signals (26) are transmitted superimposed, in particular simultaneously. Procedure according to Claim 1 or 2 , characterized in that at least two electromagnetic signals (26) which are distinguishable with regard to their form, in particular with regard to their wavelength, modulation frequency, coding or the like, are transmitted. Method according to one of the preceding claims, characterized in that at least one orientation variable, in particular a direction of a surface normal (36), is determined using the at least one received variable (32) and taking into account the respective setting of the polarization direction (H, V), wherein the at least one orientation variable characterizes an orientation of at least one object target (28), in particular an orientation of the surface of at least one object target (28) at which the at least one electromagnetic signal (26, 30) is reflected, relative to at least one reference system (22), in particular relative to a coordinate system. Procedure according to Claim 4 , characterized in that using at least one orientation variable, at least one property, in particular an orientation and/or a type and/or class, of at least one detected object (20) with a plurality of object targets (28) is determined. Method according to one of the preceding claims, characterized in that the detection device (14) is at least temporarily set to transmit electromagnetic signals (26) with at least two different defined polarization directions (H, V) and/or the detection device (14) is at least temporarily set to receive electromagnetic signals (30) with at least two different defined polarization directions (H, V). Method according to one of the preceding claims, characterized in that the detection device (14) is switched at least temporarily between at least two transmission sequences (44) for transmitting electromagnetic signals (26) with at least two different defined polarization directions (H, V) and is set to receive electromagnetic signals (30) with the at least two polarization directions (H, V) of the transmitted electromagnetic signals (26) and is not switched between the at least two transmission sequences (44) and/or the detection device (14) is not switched at least temporarily between at least two transmission sequences (44) for transmitting electromagnetic signals (26) with respect to the polarization direction (H, V) and is switched between the at least two transmission sequences (44) for receiving electromagnetic signals (30) with at least two different defined polarization directions (H, V) and/or the detection device (14) is switched at least temporarily between at least two transmission sequences (44) both for transmitting electromagnetic signals (26) as well as for receiving electromagnetic signals (30) each with at least two different defined polarization directions (H, V). Method according to one of the preceding claims, characterized in that the detection device (14) is set to use electromagnetic signals (26, 30) with two orthogonal polarization directions (H, V) and/or the detection device (14) is set to use electromagnetic signals (26, 30) with a horizontal polarization direction (H) and a vertical polarization direction (V) and/or the detection device (14) is set to use electromagnetic signals (26, 30) with two orthogonal polarization directions (H, V) which are aligned with the axes of a three-dimensional vehicle coordinate system (22). Method according to one of the preceding claims, characterized in that the method is used for operating a detection device (14) which is designed as a LiDAR system or radar system. Detection device (14), in particular a detection device (14) for a vehicle (10), which has at least some of the means for transmitting electromagnetic signals (26) into a monitoring area (18), for receiving electromagnetic signals (30) reflected in the monitoring area (18) and for converting the received electromagnetic signals (30) into received variables (32) which can be processed by suitable evaluation means (34), and for at least temporarily setting the detection device (14) to use electromagnetic signals (26, 30) with defined polarization directions (H, V), characterized in that the detection device (14) has at least some of the means for carrying out the method according to one of the Claims 1 until 9 has. Driver assistance system (12) with at least one control unit (16) and with at least one detection device (14) for monitoring at least one monitoring area (18), wherein the driver assistance system (12) has at least some of the means for transmitting electromagnetic signals (26) into a monitoring area (18), for receiving electromagnetic signals (30) reflected in the monitoring area (18) and for converting the received electromagnetic signals (30) into received variables (32) that can be processed with suitable evaluation means (34), and for at least temporarily setting for the use of electromagnetic signals (26, 30) with defined polarization directions (H, V), characterized in that the driver assistance system (12) has at least some of the means for carrying out the method according to one of the Claims 1 until 9 has. Vehicle (10) with at least one detection device (14) for monitoring at least one monitoring area (18), wherein the vehicle (10) has at least some of the means for transmitting electromagnetic signals (26) into a monitoring area (18), for receiving electromagnetic signals (30) reflected in the monitoring area (18) and for converting the received electromagnetic signals (30) into received variables (32) that can be processed by suitable evaluation means (34), and for at least temporarily setting for the use of electromagnetic signals (26, 30) with defined polarization directions (H, V), characterized in that the vehicle (10) has at least some of the means for carrying out the method according to one of the Claims 1 until 9 has.