Method for determining at least one trigger threshold value for at least one receiving channel of an optical detection device

Abstract

The invention relates to a method for determining at least one trigger threshold value (THRch) for at least one receiving channel of an optical detection device, in particular an optical detection device for a vehicle, having multiple receiving channels. The receiving channels each have at least one receiving element for optical beams. The receiving channels are designed to provide receiving variables (INT) which characterize the energy of the optical beams received by the respective at least one receiving element. The optical detection device is put into operation in order to receive optical beams. Respective receiving variables (INT) are provided by at least two of the receiving channels of the optical detection device. For at least one of the receiving channels of the optical detection device, an associated channel trigger threshold value (THRch) is determined on the basis of the receiving variables (INT) provided by the at least two receiving channels.

Description

[0001] 1 / 33 2023PF01464

[0002] Description

[0003] Method for determining at least one trigger threshold value for at least one receiving channel of an optical detection device

[0004] Technical field

[0005] The invention relates to a method for determining at least one trigger threshold value for at least one receiving channel of an optical detection device, in particular an optical detection device for a vehicle, with several receiving channels, wherein the receiving channels each have at least one receiving element for optical rays and the receiving channels are designed to provide received quantities that characterize the energy of the optical rays received with the respective at least one receiving element.

[0006] Furthermore, the invention relates to a method for operating a detection device, in particular an optical detection device for a vehicle, with several receiving channels, wherein the receiving channels each have at least one receiving element with which optical rays are received, and receiving parameters are provided with the receiving channels which characterize the energy of the optical rays received with the respective at least one receiving element.

[0007] Furthermore, the invention relates to an algorithm, in particular a software algorithm, with which a method for determining at least one trigger threshold value for at least one receiving channel of an optical detection device, in particular an optical detection device for a vehicle, with several receiving channels can be carried out, wherein the receiving channels each have at least one receiving element for optical rays.

[0008] Furthermore, the invention relates to an image receiver, in particular an imager chip, for an optical detection device, especially for an optical detection device for a vehicle, with multiple receiving channels, wherein the receiving channels each have at least one receiving element for optical beams, and wherein the image receiver has means configured to carry out a method for determining at least one trigger threshold value for at least one of the receiving channels. 2 / 33 2023PF01464

[0009] Furthermore, the invention relates to an optical detection device, in particular an optical detection device for a vehicle, with several receiving channels, wherein the receiving channels each have at least one receiving element for optical rays, wherein the optical detection device has means which are configured to carry out a method for determining at least one trigger threshold value for at least one of the receiving channels.

[0010] Furthermore, the invention relates to a driver assistance system with at least one optical detection device having several receiving channels, wherein the receiving channels each have at least one receiving element for optical beams, wherein the driver assistance system has means which are configured to carry out a method for determining at least one trigger threshold value for at least one of the receiving channels.

[0011] Furthermore, the invention relates to a vehicle with at least one optical detection device having several receiving channels, wherein the receiving channels each have at least one receiving element for optical rays, wherein the driver assistance system has means which are configured to carry out a method for determining at least one trigger threshold value for at least one of the receiving channels.

[0012] State of the art

[0013] From US patent 20200249326 A1, a lidar system is known that, based on a channel output, identifies a false positive feedback and / or suppresses a corresponding false positive detection. In some cases, this false positive is caused by strong reflection from a highly reflective surface, resulting in light passing from a first channel to a second channel. The lidar system can identify feedback detected in the second channel as a false positive if it has an intensity much lower than feedback in the first channel and indicates a distance equal to or very close to the distance indicated by the feedback in the first channel. Based at least partially on identifying feedback as a false positive, the lidar system can suppress a false detection associated with the false positive by modifying a detection threshold. 3 / 33 2023PF01464

[0014] The invention is based on the objective of designing a method for determining at least one trigger threshold, a method for operating a detection device, an algorithm, an image receiver, an optical detection device, a driver assistance system, and a vehicle of the type mentioned above, in which the detection of optical rays emanating from objects in the field of view of the optical detection device can be improved. In particular, crosstalk effects between receiving channels are to be compensated.

[0015] Disclosure of the invention

[0016] According to the invention, the object of the method is achieved by putting the optical detection device into operation to receive optical rays, by providing respective received quantities with at least two of the receiving channels of the optical detection device, and by determining an associated channel trigger threshold for at least one of the receiving channels of the optical detection device based on the received quantities provided with the at least two receiving channels.

[0017] The optical detection device is put into operation, in particular for carrying out a measurement. During operation, the optical detection device receives optical beams that strike receiving elements of the receiving channels and converts them into the respective received quantities. According to the invention, at least one trigger threshold is determined as a channel trigger threshold for at least one receiving channel based on the received quantities of at least two of the receiving channels. In this way, the channel trigger threshold for the corresponding receiving channel is adjusted depending on the energy of the optical beams that strike other receiving channels, in particular receiving channels with adjacent receiving elements. This compensates for any crosstalk effects on the receiving channel for which the channel trigger threshold is determined, which can be caused by the energy of the optical beams of the other receiving channels.

[0018] Due to non-ideal optical and / or electronic components, undesirable effects may occur, in particular optical and / or electrical crosstalk effects between receiving channels struck by high-energy optical beams and nearby receiving channels struck by lower-energy optical beams.

[0019] In particular, if optical rays are reflected by retroreflective objects and strike receiving elements of the optical detection device's receiving channels, crosstalk effects to adjacent receiving channels can occur. If the adjacent receiving channels, in turn, receive reflected optical rays from normally reflected objects near the retroreflective object, the corresponding received values ​​will be distorted by the crosstalk effect.

[0020] The inventive method determines the respective trigger thresholds, namely the channel trigger thresholds, depending on the influence of optical rays received by the receiving channels. The channel trigger thresholds of the receiving channels are adjusted so that any crosstalk effects from receiving channels in direct or indirect proximity, which are struck by strong object rays, are not considered as rays originating from an object for the corresponding receiving channel.

[0021] The method according to the invention makes it possible to individually adjust the channel trigger thresholds for the receiving channels so that even normally reflecting or slightly reflecting objects can be detected by the detection device and distinguished from highly reflecting, especially retroreflective, objects. In this way, the dynamic range detectable by the optical detection device with respect to the energy of received optical rays can be increased.

[0022] The receiving channels each have at least one receiving element for optical rays. The receiving elements form the input of the receiving channels for optical rays. The optical rays strike the receiving elements and are subsequently converted into quantities, in particular electrical signals, which can be further processed. Advantageously, the optical rays can be converted into received quantities by the receiving elements. In this way, the 5 / 33 2023PF01464

[0023] Received parameters can be processed directly.

[0024] A trigger threshold is the value of a received signal above which the reception of optical rays emanating from an object within the field of view of the optical detection device is detected. As soon as a receiving channel provides a signal above the trigger threshold, the detection of an object by that corresponding receiving channel is triggered, and the object is detected. The channel trigger threshold is the trigger value assigned to the corresponding receiving channel.

[0025] Optical rays emanating from an object can also be referred to as optical object rays for the sake of simplicity. These optical object rays can be reflected optical rays, particularly optical echo rays from optical scanning rays reflected off an object. The scanning rays can originate from a transmitting device of an optical detection device designed as an active optical detection device, especially a LiDAR system. Optical object rays can also be ambient optical rays reflected off an object, which can be detected by an optical detection device designed as a passive optical detection device, particularly a camera.

[0026] "Optical" within the meaning of the invention refers to visible and invisible ranges of electromagnetic radiation, in particular light radiation. The components designated as "optical" are accordingly suitable for use in connection with electromagnetic radiation that is visible to humans and invisible to humans. The optical radiation can be light radiation, in particular laser radiation, in the visible or invisible range. The optical components can be optical components such as optical lenses, electro-optical components such as light sources or sensors, or other components that have at least one optical effect or function, or a combination of such components.

[0027] The optical detection device can be an active optical detection device, such as a LiDAR system, or a passive optical detection device, such as a camera. The optical detection device has receive channels with which a 6 / 33 2023PF01464

[0028] Optical rays (object rays) approaching an object in the field of view of the optical detection device can be received. The invention can be used in flash LiDAR systems and scanning LiDAR systems. Furthermore, the invention can be used in optical detection devices with one-dimensional receiving devices, which in particular have receiving elements arranged in rows, or in two-dimensional receiving devices which have receiving elements arranged in a planar fashion, in particular in rows and columns.

[0029] The field of view of an optical detection device is the portion of the surroundings that can be detected during operation. For an active optical detection device, such as a LiDAR system, the field of view can be characterized by superimposing the illumination field of the device's transmitter and the receiving field of the device's receiver. For a passive detection device, such as a camera, the field of view can be characterized by an optical system, in particular a camera lens, an image receiver such as an imager chip, or the like.

[0030] The received quantities provided by the receiving channels contain a portion of converted optical rays striking the receiving elements of the respective channels, as well as system noise. The received quantities belonging to a given receiving channel characterize the energy of the optical rays striking the corresponding receiving element. This received quantity can characterize intensity, strength, luminous flux, the duration of an optical beam pulse, or a combination thereof.

[0031] The optical rays striking the receiving elements of the receiving channels consist of ambient optical rays and, if an object is located in the field of view of the optical detection device, reflected optical rays coming from it (optical object rays).

[0032] The system noise is generated within the detection device, particularly within the receiving channels, in a manner not of further interest here. 7 / 33 2023PF01464

[0033] During operation of the detection device, it is necessary to reliably detect very small signal amplitudes. This is all the more important the greater the dynamic range of the optical beams received by the optical detection device is with respect to their energy. To increase the detectable dynamic range, the trigger thresholds for the receiving channels (channel trigger thresholds) are set according to the invention such that the detection of the reception of optical object beams is not falsely triggered by ambient radiation, system noise, or electrical or optical crosstalk from adjacent receiving channels.

[0034] Advantageously, each receiving channel can include conversion means for converting optical rays striking the at least one associated receiving element and for determining received quantities. In this way, the optical rays can be converted into received quantities directly within the receiving channel.

[0035] Advantageously, the received parameters can be implemented using electrical signals, especially digital signals. In this way, the received parameters can be processed electrically using electronic components, especially processors.

[0036] Advantageously, the received parameters used to determine at least one trigger threshold can be ascertained through reference measurements. For this purpose, the expected system response can be modeled as a curve of the received parameters across the receiving channels based on these reference measurements. From this, the influence of the energy of the received optical rays (which may contain object rays and ambient rays) and the system noise on the channel trigger threshold can be determined.

[0037] Advantageously, the received signals via the receiving channels can exhibit an exponential or quadratic curve. In this way, physically typical curves can be used.

[0038] Instead of reference measurements, the received parameters for determining at least one trigger threshold can also be measured during the regular operation of the optical 8 / 33 2023PF01464

[0039] The detection device can be determined. In this way, a separate reference measurement can be dispensed with.

[0040] Advantageously, a method for determining at least one trigger threshold can be performed in a post-processing step after a measurement. This allows the acquired received parameters to be analyzed for optical object rays at a later time.

[0041] Advantageously, the optical detection device can first be operated by determining the received signals for the receiving channels. These received signals can then be compared with the channel trigger thresholds of the respective receiving channels to analyze whether the receiving element of the corresponding channel has been struck by optical object rays. By first acquiring the received signals and then comparing them with the corresponding channel trigger threshold, the information contained within the received signals is preserved. This increases the amount of available information about the field of view. In contrast, using thresholds that prevent the transmission of received signals below these thresholds results in a loss of information.

[0042] In an advantageous embodiment of the method, the provided received parameters can be weighted to determine the channel trigger threshold for at least one received channel. This allows the influence of crosstalk effects between the received channels on the respective received channel for which the channel trigger threshold is to be determined to be individually considered.

[0043] In a further advantageous embodiment of the method, the provided received parameters can be weighted depending on the respective relationship of the receiving channels with which they are provided to the at least one receiving channel for which the channel trigger threshold is determined. In particular, the provided received parameters can be weighted depending on the respective relative position, especially a distance, of the receiving elements of the receiving channels with which they are provided to the receiving element of the at least one receiving channel for which the channel trigger threshold is determined. (See 9 / 33 2023PF01464)

[0044] In this way, the influences of crosstalk effects of the received parameters of the considered receiving channels on the receiving channel for which the channel trigger threshold is to be determined can be taken into account more precisely.

[0045] Advantageously, the provided received parameters can be weighted according to the relative position, in particular the distance, of the receiving elements of the receiving channels with which they are provided to the receiving element of the at least one receiving channel for which the channel trigger threshold is determined. In this way, it can be taken into account that crosstalk effects decrease with the distance between the receiving channels, and in particular between the receiving elements of the receiving channels. The closer the corresponding receiving elements are to each other, the greater the probability of crosstalk effects.

[0046] Advantageously, weighting can be achieved by using weighting factors. The respective received parameters can be multiplied by the weighting factors. The greater the influence of a received channel on the received channel for which the channel trigger threshold is to be calculated, the larger the corresponding weighting factor can be. For received channels whose receiving elements are in close proximity to each other, the weighting factor can be larger than for received channels whose receiving elements are further apart. In this way, the distance between the receiving elements can be easily taken into account when determining the channel trigger thresholds.

[0047] In a further advantageous embodiment of the method, at least some of the provided received parameters can be multiplied by the weighting factor (which can also be 0) belonging to the corresponding receiving channel from which the received parameter originates. The products of the received parameters and the respective weighting factors are then added, and the resulting weighted sums of the received parameters are processed to determine the channel trigger threshold. In this way, the profile of channel trigger thresholds can be calculated individually for the receiving channels. The provided received parameters can be multiplied by the respective weighting factor, which can also be 0. If the weighting factor is set to 0, the received parameter of the corresponding receiving channel is not considered when determining the channel trigger threshold. 10 / 33 2023PF01464

[0048] In a further advantageous embodiment of the procedure, the weighting factors can be specified and / or

[0049] Positions, in particular distances, of the receiving elements of the receiving channels from which received quantities are provided, relative to at least one receiving element of the receiving channel for which the channel trigger threshold is to be determined, are used to specify the weighting factors.

[0050] Advantageously, the weighting factors can be predefined. This makes the weighting factors readily available.

[0051] Advantageously, the weighting factors can be predefined based on system responses from the detection device, in particular properties of an image sensor chip, which can also be determined in advance using reference measurements. This allows the weighting factors to be determined more precisely.

[0052] Alternatively, the weighting factors can advantageously be chosen based on theoretical considerations of the system of receiving channels and their crosstalk behavior. This eliminates the need for reference measurements.

[0053] Advantageously, the positions, in particular the distances, of the receiving elements of the receiving channels from which received data is provided can be used to define the weighting factors for at least one receiving element of the receiving channel for which the channel trigger threshold is to be determined. The relative positions can be determined in advance for the corresponding detection device, in particular the image receiver. In this way, a simple estimation of the influence of the mutual crosstalk behavior of the receiving channels can be modeled.

[0054] In a further advantageous embodiment of the method, the channel trigger threshold can be determined as the sum of a summand based on the provided received parameters, in particular a weighted sum of received parameters, and at least one further threshold, in particular a system noise threshold and / or an ambient radiation threshold. In this way, in addition to the influences between the received channels themselves, which can be caused by electrical and / or optical crosstalk, further influences caused by system noise and / or ambient radiation can be taken into account. Thus, the channel trigger thresholds can be set even more precisely. A greater dynamic range with respect to the energy of received optical object rays can therefore be captured.

[0055] Advantageously, in a one-dimensional image receiver where the receiving elements of the receiving channels are arranged side by side in a line, the channel trigger threshold THRch.x can be calculated according to the following formula, taking into account the three nearest neighbors of the receiving element of the receiving channel for which the channel trigger threshold TH Reh, x is to be calculated: where THRrausch is the threshold for system noise, THRumg is the threshold for ambient radiation, INTindex is the received signal strength of the receiving channel with the corresponding index, and aindex is the weighting factor for the receiving channel with the corresponding index. X is the index for the receiving channel for which the channel trigger threshold is to be calculated.

[0056] In this way, the channel trigger threshold for a one-dimensional image receiver can be efficiently determined.

[0057] Alternatively, for a one-dimensional image receiver, the channel trigger threshold THRch.x can advantageously be calculated for each of the receiving channels according to the following formula, taking into account all receiving channels except the receiving channel for which the channel trigger threshold TH Reh, x is to be calculated: 12 / 33 2023PF01464 where THRrausch is the threshold for system noise, THRumg is the threshold for ambient radiation, INTi is the received signal of the receiving channel with the corresponding index i, and ai is the weighting factor for the receiving channel with the corresponding index i. Furthermore, i is the running index for the receiving channels and x is the index for the receiving channel for which the channel trigger threshold THRch.x is to be calculated. For the receiving channel x for which the channel trigger threshold THRch.x is to be calculated, the weighting factor ai is xA value of 0 is specified. This means that the corresponding received value is not taken into account.

[0058] Advantageously, in a two-dimensional image receiver where the receiving elements of the receiving channels are arranged planarly in rows and columns, the channel trigger threshold TH Reh, x,y for each of the receiving channels can be calculated according to the following formula, where all receiving channels except the receiving channel for which the channel trigger threshold THR C The following should be taken into account when calculating h, x, y: where THRrausch is the threshold for system noise, THRumg is the threshold for ambient radiation, INTi is the received parameter of the receiving channel with the corresponding indices i, j, and aij is the weighting factor for the receiving channel with the corresponding indices i, j. Furthermore, i is the running index for the columns in which the received elements of the receiving channels are located, j is the running index for the rows of the receiving channels, and x, y are the indices for the rows and columns in which the received element of the receiving channel, for which the channel trigger threshold THRch.x is to be calculated, is located. For the receiving channel x, y, for which the channel trigger threshold THR is to be calculated... C To calculate h,x,y, the weighting factor a x , y A value of 0 is specified. This means that the corresponding received value is not taken into account.

[0059] In a further advantageous embodiment of the method, at least some of the provided received parameters can be used to determine the channel trigger threshold for the at least one received channel. These parameters originate from received channels whose receiving elements are located no more than three receiving elements away from the at least one receiving element belonging to the at least one received channel for which the channel trigger threshold is to be determined. In this way, only received channels whose receiving elements are in close proximity to the relevant receiving element of the received channel for which the channel trigger threshold is to be determined need to be considered. This accelerates the determination of the channel trigger thresholds, as not all received channels need to be taken into account.

[0060] In a further advantageous embodiment of the method, received signals from the at least one receiving channel for which the channel trigger threshold is determined can be excluded from the determination of that threshold. This avoids feedback during the determination of the channel trigger threshold. Only the influence of received signals from channels in the vicinity of the receiving channel for which the channel trigger threshold is to be determined is considered.

[0061] In a further advantageous embodiment of the method, the procedure for determining at least one trigger threshold can be carried out using an image receiver, in particular an imager chip, which includes at least the receiving elements of the receiving channels. In this way, the channel trigger thresholds can be determined at an early stage of the signal processing chain. The channel trigger thresholds are then available for further processing of the received signals at an early stage. The channel trigger thresholds can then be used to decide whether the received signals of the receiving channels can be attributed to the detection of an object. The received signals can be attributed to the detection of an object if they exceed the corresponding channel trigger threshold.

[0062] In a further advantageous embodiment of the method, the method for determining at least one trigger threshold value for at least one receiving channel of an active optical detection device, in particular a LiDAR system, can be carried out and / or the method for determining at least one trigger threshold value for at least one receiving channel of a passive optical detection device, in particular a camera, can be carried out.

[0063] Advantageously, the method for determining at least one trigger threshold can be carried out for at least one receiving channel of an active optical detection device. With active optical detection devices, such as LiDAR systems, optical scanning beams can be transmitted into a monitoring area, and optical echo signals reflected from objects can be received. Distances, directions, velocities, or similar properties of the objects can be determined from the received optical echo signals. The invention enables an active optical detection device to detect both weakly reflective objects and strongly reflective objects, particularly retroreflective objects, that are located nearby. The invention increases the dynamic range of the optical detection device with respect to the energy of optical beams.

[0064] Alternatively or additionally, the method for determining at least one trigger threshold value for at least one receiving channel of a passive optical detection device, in particular a camera, can be carried out. In this way, optical rays emanating from objects, which are caused in particular by ambient light such as sunlight or other external light sources, for example streetlights or the like, can be detected. The invention enables a passive optical detection device to detect both weakly reflective objects and strongly reflective objects, in particular retroreflective objects, that are located nearby. The invention increases the dynamic range of the optical detection device with respect to the energy of optical rays.

[0065] Furthermore, the object of the invention is solved in the method for operating a detection device by carrying out a method according to the invention for determining at least one channel trigger threshold value, which is applied to the received quantity provided by the corresponding receiving channel, 15 / 33 2023PF01464 if the received quantity is above the at least one channel trigger threshold value, the received quantity is drawn as a detection.

[0066] According to the invention, individual channel trigger thresholds are determined for at least some of the receiving channels from the received signals of adjacent receiving channels. The channel trigger threshold is applied to the received signals received by the corresponding receiving channel. The received signal is then identified as a detection if it is above the corresponding channel trigger threshold. In this way, interference from crosstalk effects is corrected.

[0067] Advantageously, the received data, which were identified as detections, can be fed into a point cloud for the detection device to use. In this way, a precise image of the detected object can be created.

[0068] Furthermore, the problem is solved according to the invention in the algorithm by the fact that the algorithm is designed to carry out the method according to the invention for determining at least one trigger threshold value.

[0069] According to the invention, the method for determining at least one trigger threshold is carried out using an algorithm. The method can be uniquely defined by an algorithm. An algorithm can be stored in appropriate hardware, in particular a processor or the like.

[0070] Advantageously, the algorithm can be stored in the detection device. In this way, the procedure can be carried out directly in the detection device.

[0071] Advantageously, the algorithm can be implemented using software. This makes it easier to integrate the algorithm into the appropriate hardware.

[0072] Furthermore, the object of the invention is solved in the image receiver by the fact that the image receiver has means which are designed to carry out the method according to the invention for determining at least one trigger threshold value.

[0073] According to the invention, the image receiver can include means for carrying out the method according to the invention. In this way, the method according to the invention can be carried out directly in the image receiver. Thus, the method according to the invention can be carried out very far upstream in the signal processing chain.

[0074] Advantageously, the image receiver can include software means for carrying out the method according to the invention. In this way, the method can be implemented in the form of an algorithm.

[0075] Advantageously, the image receiver can include hardware means for carrying out the method according to the invention. In this way, optical beams and received quantities, in particular electrical received quantities, can be processed. Furthermore, the hardware means can be configured for executing software programs. The hardware means can include memory and processors. In this way, software programs can be executed.

[0076] Furthermore, the object of the invention is achieved in the optical detection device by the fact that the optical detection device has means which are designed to carry out the method according to the invention for determining at least one trigger threshold value.

[0077] According to the invention, the optical detection device includes means for carrying out the method according to the invention. In this way, the method can be carried out in the optical detection device. Thus, the optical detection device can output both the received parameters and the associated channel trigger thresholds.

[0078] Furthermore, the optical detection device can include means for processing the received signals and comparing them with the respective channel trigger thresholds. Thus, received signals can be validated as object detections directly within the optical detection device. Additionally, object information such as distances, velocities, and / or directions, or similar characteristics of detected objects, can be determined.

[0079] The means for carrying out the method according to the invention can be implemented by software and / or hardware. The method can be implemented as an algorithm by software. Optical beams, received signals, in particular electrical signals, and the like can be processed by hardware. Furthermore, software means can be integrated into hardware means.

[0080] Furthermore, the problem is solved according to the invention in the driver assistance system by the fact that the driver assistance system has means which are designed to carry out the method according to the invention for determining at least one trigger threshold value.

[0081] The driver assistance system comprises at least one optical detection device. This optical detection device can monitor areas inside and / or outside a vehicle. Information about these areas, obtained by the at least one optical detection device, can be transmitted to a control unit of the driver assistance system. Based on the information provided by the at least one optical detection device, the control unit can autonomously or semi-autonomously control functions of the vehicle, particularly driving functions.

[0082] Using the method according to the invention, received parameters determined by the receiving channels of the optical detection device can be assigned more efficiently and accurately to corresponding objects detected by the optical detection device. This improves the quality of the information transmitted by the optical detection device to the control unit of the driver assistance system. This, in turn, improves the overall control of the vehicle's functions. This leads to an increase in the vehicle's operational safety, particularly its driving safety. 18 / 33 2023PF01464

[0083] Furthermore, the object of the invention is achieved in the vehicle by the fact that the vehicle has means which are designed to carry out the method according to the invention for determining at least one trigger threshold value.

[0084] The at least one optical detection device allows monitoring areas inside and / or outside the vehicle to be monitored for objects. Information obtained with the at least one optical detection device can be made available to the vehicle's driver and / or a driver assistance system.

[0085] The optical detection device according to the invention has several receiving channels and means for carrying out the method according to the invention. Advantageously, the optical detection device can have at least one image receiver, in particular at least one image receiver according to the invention, with several receiving channels. The driver assistance system according to the invention has at least one optical detection device, in particular an optical detection device according to the invention, and means for carrying out the method according to the invention. The vehicle has at least one optical detection device, in particular an optical detection device according to the invention, and means for carrying out the method according to the invention. Since the image receiver, in particular the image receiver according to the invention, is part of the optical detection device, the means of the image receiver are also part of the optical detection device.Since the at least one detection device, in particular the at least one detection device according to the invention, is part of the driver assistance system or the vehicle, the means of the at least one detection device, in particular the image receiver, are also part of the driver assistance system or the vehicle. The same applies to the means of the driver assistance system, which is part of the vehicle.

[0086] Furthermore, the provisions relating to the inventive method for determining at least one trigger threshold value, the inventive method for operating a detection device, the inventive algorithm, the inventive image receiver, the inventive optical detection device 19 / 33 2023PF01464 apply.

[0087] The features and advantages of the device, the driver assistance system according to the invention, and the vehicle according to the invention, and their respective advantageous embodiments, correspond to each other and vice versa. The individual features and advantages can, of course, be combined with one another, potentially resulting in further advantageous effects that go beyond the sum of the individual effects.

[0088] Brief description of the drawings

[0089] 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 drawing. The person skilled in the art will expediently consider the features disclosed in the drawing, the description, and the claims individually and combine them into meaningful further combinations. The drawing schematically illustrates

[0090] Figure 1 shows a vehicle with a driver assistance system which has an optical detection device with which an object in the direction of travel in front of the vehicle can be detected;

[0091] Figure 2 shows a sequence of received quantities provided when the object from Figure 1 is detected during operation of the detection device with its receiving channels, wherein the received quantities characterize the energy of the optical rays coming from the object;

[0092] Figure 3 shows a progression of the channel trigger thresholds for the receiving channels, which are determined from the received parameters of the respective adjacent receiving channels;

[0093] Figure 4 shows a method for operating the detection device from Figure 1.

[0094] In the figures, identical components are labelled with the same reference symbols.

[0095] embodiment(s) of the invention

[0096] Figure 1 shows a top view of a vehicle 10. The vehicle 10 includes a driver assistance system 12. With the aid of the driver assistance system 12, functions of the vehicle 10, such as driving functions, can be controlled autonomously or semi-autonomously. 20 / 33 2023PF01464

[0097] The driver assistance system 12 comprises an optical detection device 14 and a control unit 16.

[0098] The optical detection device 14 can monitor a monitoring area 18 in the direction of travel in front of the vehicle 10 for objects 20. In Figure 1, an object 20 in the form of a road sign is indicated by way of example. The object 20 is located in a field of view 22 of the detection device 14. The field of view 22 of the detection device 14 is directed into the monitoring area 18.

[0099] Information obtained by the detection device 14 over the monitoring area 18 can be transmitted to the control unit 16. The control unit 16 can use the information to control the functions of the vehicle 10.

[0100] The detection device 14 is, for example, designed as a LiDAR system. The detection device 14 comprises a transmitter 24, a receiver 26, and a control and evaluation unit 28.

[0101] The field of view 22 of the detection device 14 results from the overlap of the field which can be emitted by the transmitting device 24 and the receiving field which can be seen by the receiving device 26.

[0102] The transmitter 24 can send optical scanning beams 30 in the form of laser pulses into the monitoring area 18. The transmitter 24 has one or more laser diodes with which the optical scanning beams 30 can be generated.

[0103] The detection device 14 can, for example, be designed as a flash LiDAR system. In this case, optical scanning beams 30, similar to a flashlight, are sent into the monitoring area 18. However, the invention is not limited to flash LiDAR systems. It can also be used with other types of detection devices, such as scanning LiDAR systems, cameras, or the like.

[0104] The transmitter 24 is connected to the control and evaluation unit 28. The transmitter 24 can be controlled in coordination with the receiver 26 using the control and evaluation unit 28 (part number 21 / 33 2023PF01464).

[0105] If the optical scanning beams 30 strike an object 20, they are reflected. For the sake of simplicity, the scanning beams 30 reflected from the object 20 are referred to below as object beams 32H and 32N.

[0106] The energy of the optical object rays 32 depends on the reflectance of the surface of the object 20 struck by the scanning rays 30. The object 20 shown in Figure 1, in the form of a road sign, has a retroreflective surface 34 at its center. The retroreflective surface 34 is located between two normally reflecting surfaces 36. The energy of the object rays 32H reflected by the retroreflective surface 34 is significantly greater than the energy of the object rays 32N reflected by the normally reflecting surfaces 36.

[0107] The object rays 32N and 32H, which are reflected towards the receiving device in the direction of the detection device 14, can be received by the receiving device 26.

[0108] The receiver 26 has an image receiver chip 38. The image receiver chip 38 can also be referred to as an imager chip. In the illustrated embodiment, a one-dimensional image receiver chip 38 is provided. The image receiver chip 38 has, by way of example, 100 receiving channels 40. For the sake of clarity, only a few of the receiving channels 40 are indicated in Figure 1. An alternatively usable image receiver chip can also have more or fewer than 100 receiving channels 40.

[0109] Each receiving channel 40 has a receiving element 42. In the illustrated embodiment, the receiving elements 42 of the one-dimensional image receiver chip 38 are arranged horizontally side by side in a line. In this way, a horizontal image of the monitored area 18 can be obtained with the detection device 14 shown.

[0110] The optical object rays 32N and 32H can be converted into electrical quantities by the receiving elements 42. These electrical quantities can be processed into received quantities INT using appropriate means. In the image receiver chip 38 used, these processing means are part of the receiving channels 40. The received quantities 44 characterize the energy of the object rays 32N and 32H received by the respective receiving channels 40.

[0111] It is possible for a receiving element 42 to be struck by both strong object rays 32H and weak object rays 32N. Therefore, the respective subscripts H and N are omitted from the reference symbol for the received quantities INT.

[0112] Instead of a one-dimensional image receiver chip 38, a two-dimensional image receiver chip can also be used. In this case, the receiving elements 42 are arranged two-dimensionally, for example in rows and columns. The rows can run horizontally and the columns vertically. In this way, a two-dimensional image of the monitoring area 18 can be obtained with the two-dimensional image receiver chip 38.

[0113] In addition to the object rays 32N and 32H, the receiving channels 40 also receive any ambient optical rays 44 that may be present and which strike the respective receiving elements 42. The energy of the ambient rays 44 is also included in the received quantities INT of the respective receiving channels 40. Furthermore, the signal noise of the receiving channels 40 is also included in the received quantities INT.

[0114] If strong optical object rays 32H strike a receiving element 42 of a receiving channel 40, this can cause crosstalk effects on adjacent receiving channels 40. The crosstalk effects lead to a distortion of the received quantities INT of receiving channels 40 whose receiving elements 42 are struck by weaker object rays 32N.

[0115] Figure 2 shows an example of the curve 46 of the received parameters INT for channels 1 to 100, which results from a measurement on the object 20 shown in Figure 1. The object 20 is located directly in front of the detection device 14. 23 / 33 2023PF01464

[0116] The axis for channels 44 is labeled CH. Object 20 is indicated above the curve 46 for easier orientation. For comparison only, the ideal curve 46id for the received parameters INT, assuming no crosstalk effects, is shown as a dashed line. The curve 46 for the received parameters INT is shown as a curve in Figure 1. In reality, the received parameters INT are discrete values ​​assigned to the respective received channels 40. The curve shown is the envelope for the received parameters INT.

[0117] For the receiving channels 40, which are struck by weaker object rays 32N, measurement errors 52 occur due to crosstalk effects. The measurement errors 52 are indicated in Figure 2 by hatched areas between the measured path 46 and the ideal path 46id.

[0118] Figure 2 shows, by way of example, the maximum received quantity INT H.max, which is caused by strong object rays 32H originating from the center of the highly reflective surface 34 of the object 20, ambient rays 44, and system noise, approximately in receive channel 40 numbered 50. The outer receive channels 40 numbered 1 and 100 are hardly affected by crosstalk effects. Thus, the received quantity INT there is at the level caused by the weak object rays 32 originating from the normally reflective surfaces 36, the ambient rays 44, and the system noise.

[0119] To correct for the influence of crosstalk effects, ambient radiation 44, and system noise, an individual channel trigger threshold TH Reh is determined for each receiving channel 40. The channel trigger threshold TH Reh specifies the value of the received parameters INT above which the reception of optical object rays 32N or 32H emanating from the object 20 in the field of view 22 of the detection device 14 is detected. When optical object rays 32N or 32H are detected, this is recorded as a detection of the object 20.

[0120] The respective channel trigger threshold TH Reh is selected so that it lies above a value for a received quantity INT that is caused exclusively by ambient radiation 44 and signal noise. Received quantities INT that are below the channel trigger threshold THRch are not considered to be caused by object radiation 24 / 33 2023PF01464

[0121] processed, originating from object 20 or 32N or 32H.

[0122] The image receiver chip 38 includes a processor 48. The processor 48 comprises an algorithm 50, indicated in Figure 4, which can be used to determine the channel trigger thresholds THRch. The algorithm 50 is implemented as a software program.

[0123] Figure 3 shows the curve 54 for the channel trigger thresholds THRch, which result from the curve 46 of the received quantities INT in Figure 2. The curve 54 for the channel trigger thresholds THRch is similar to the curve 46 for the received quantities INT from Figure 2. The curve 54 has its maximum at receive channel 40 numbered 50. There, the influence of crosstalk effects from adjacent receive channels 40, which are struck by strong object rays 32H, is greatest. The minima of the curve 54 are located at receive channels 40 numbered 1 and 100. There, the influence of crosstalk effects from adjacent receive channels 40, which are struck by strong object rays 32H, is smallest.

[0124] The curve of the channel trigger thresholds THRch is shown in Figure 3. In reality, the channel trigger thresholds THRch are discrete values ​​assigned to the respective receive channels 40. The curve shown is the envelope for the channel trigger thresholds THRch.

[0125] Figure 4 shows a method for operating the detection device 14. The method includes a procedure for determining the channel trigger thresholds THRch for the receive channels 40 of the detection device 14.

[0126] First, in step 56, a measurement is performed using the detection device 22. Optical scanning beams 30 are sent into the monitoring area 18. The detection device 14, namely the receiving device 26, is activated to receive optical beams, specifically the optical object beams 32N and 32H.

[0127] In step 58, the respective received quantities INT are provided via the receiving channels 40. The received quantities INT characterize the energy of the rays, namely the object rays 32N and 32H, and the optical ambient rays 44, which are received via the corresponding receiving channels 40. Furthermore, the signal noise is included in the received quantities INT.

[0128] In step 60, the respective channel trigger threshold TH Reh is determined for each of the receiving channels 40 on the basis of the receiving channels 44, whose respective receiving elements 42 are arranged in the vicinity of the receiving element 42 of the receiving channel 40 for which the channel trigger threshold THRch is determined.

[0129] For this purpose, the exemplary algorithm 50 is used. In algorithm 50, the three nearest neighbors of the receiving element 42 of the receiving channel 40, for which the channel trigger threshold TH Reh, x is to be calculated, are taken into account. Algorithm 50 is as follows:

[0130] Here, THRrausch is the threshold for system noise. THRumg is the threshold for ambient radiation. 44. INT x -3, INT x -2, INT x -i, INTx+i, INTx+2 and INTx+3 are the received values ​​of the adjacent receive channels 40. a x -3, a x -2, a x -i, a x+ i, a x+ 2 and a x+ 3 are the weighting factors for the corresponding receiving channels 40. The index x denotes the receiving channel 40 for which the channel trigger threshold TH Reh, x is to be calculated.

[0131] The weighting factors a x -3, a x -2, a x -i, ax+ i, a x+ 2 and a x+ 3 can, for example, contain spatial positions of the respective receiving elements 42 of the adjacent receiving channels 40 relative to the receiving element 42 of the receiving channel 40 for which the channel trigger threshold THRch is determined. The weighting factors a x -3, a x -2, a x -i, a x+ i, ax+2 and a x+ 3 can also be selected based on a system response from a reference measurement or based on a theoretical consideration of the system with the receiving device 26 and its crosstalk.

[0132] If, for the receive channels 40, there are no three adjacent receive channels 40 on one side, the corresponding intensity values ​​INT are equal to 0. 26 / 33 2023PF01464

[0133] In algorithm 50, the provided received quantities INT are each multiplied by the weighting factor a, which can also be 0, belonging to the corresponding receiving channel 40 from which the received quantity INT originates. The products of received quantities INT and the respective weighting factors a are added. The resulting weighted sums of received quantities are processed to determine the channel trigger threshold THRch, using the threshold THRrausch for system noise and the threshold THRumg for ambient radiation 44, namely by summing them.

[0134] The determined individual channel trigger thresholds THRch are provided in step 62.

[0135] In step 64, the respective channel trigger thresholds THRch are applied to the received quantities INT provided by the corresponding receive channel 40. Those received quantities INT that are above the corresponding channel trigger threshold THRch are marked as detections.

[0136] In step 66, the received quantities INT, which are marked as detections, are fed to a point cloud 68 with further information via the corresponding receiving channel 40, for example distance quantities, direction quantities and / or velocity quantities.

[0137] In step 72, the point cloud 68 is transmitted to the control unit 16.

[0138] Steps 64 to 68 can be performed in the control and evaluation unit 28.

[0139] In an alternative algorithm 50, instead of considering only the received parameters INT of the three nearest neighbors of the corresponding received channel 40, the received parameters INT of all received channels 40 are used, except for the received channel 40 for which the channel trigger threshold TH Reh, x is to be calculated. The following algorithm 50 is performed for this purpose: 27 / 33 2023PF01464

[0140] Here, THRrausch is the threshold for system noise. THRumg is the threshold for ambient radiation. The index i denotes the individual receive channels 40. INTi are the received parameters of the receive channels 40 with the corresponding index i. ai are the respective weighting factors for the receive channels 40 with the corresponding index i. The index x denotes the receive channel 40 for which the channel trigger threshold TH Reh, x is to be calculated. Since a receive channel 40 has no crosstalk effect on itself, the weighting factor a is assigned to the receive channel 40 with index x for which the channel trigger threshold TH Reh, x is to be calculated. x A value of 0 is specified. This means that the corresponding received parameter INTx is not taken into account.

[0141] In a further embodiment of an optical detection device 14 (not shown) with a receiving device 26, which has a two-dimensional image receiver chip 38, the channel trigger thresholds THR can be C h,x, y The number 50 can be determined according to the following algorithm:

[0142] Here, THRrausch is the threshold for system noise. THRumg is the threshold for ambient radiation, "n" is the number of rows of the image receiver chip 38, and "m" is the number of columns of the image receiver chip 38. "i" is the index for the rows containing the receiving elements of the receiving channels, and "j" is the index for the columns of the receiving channels. The index x denotes the row and the index y the column containing the receiving element 42 of receiving channel 40, for which the channel trigger threshold THR is to be calculated. INTi is the received value of receiving channel 40 in row i and column j. "au" is the weighting factor for receiving channel 40 in row i and column j. For receiving channel 40 with indices x and y, for which the channel trigger threshold THR is to be calculated... C To calculate h,x,y, the weighting factor a x,y = 0 is specified. This means that the corresponding received variable INT is not taken into account, since the receive channel 40 cannot crosstalk onto itself. The other weighting factors aij include, for example, the relative position of the receive elements 42 of the corresponding receive channels 40 relative to the receive element 42 of the receive channel 40 for which the channel trigger threshold THR is set. C h, x, y are to be calculated. 28 / 33 2023PF01464

[0143] Even with a two-dimensional image receiver chip 38, instead of the received quantities INT of all other received channels 40, only the received quantities INT of a part of the other received channels 40, for example the three nearest received channels 40, can be used to calculate a respective channel trigger threshold value THRch.

Claims

1. 29 / 33 2023PF01464 Claims 1. A method for determining at least one trigger threshold value (THRch) for at least one receiving channel (40) of an optical detection device (14), in particular an optical detection device (14) for a vehicle (10), with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44) and the receiving channels (40) are configured to provide received quantities (INT) that characterize the energy of the optical beams (32N, 32H, 44) received by the respective at least one receiving element (42), characterized in that the optical detection device (14) is put into operation to receive optical beams (32N, 32H, 44), with at least two of the receiving channels (40) of the optical detection device (14) providing respective received quantities (INT).for at least one of the receiving channels (40) of the optical detection device (14) an associated channel trigger threshold (THRch) is determined on the basis of the received quantities (INT) provided by the at least two receiving channels (40).

2. Method according to claim 1, characterized in that the provided received quantities (INT) are weighted to determine the channel trigger threshold (THRch) for the at least one received channel (40).

3. Method according to claim 2, characterized in that the provided received quantities (INT) are weighted depending on a respective relationship of the receiving channels (40) with which they are provided to the at least one receiving channel (40) for which the channel trigger threshold (THRch) is determined, in particular the provided received quantities (INT) are weighted depending on the respective relative position, in particular a distance, of the receiving elements (42) of the receiving channels (40) with which they are provided to the receiving element (42) of the at least one receiving channel (40) for which the channel trigger threshold (THRch) is determined.

4. Method according to one of the preceding claims, characterized in that 30 / 33 2023PF01464 at least a part of the provided received quantities (INT) is multiplied by the weighting factor, which can also be 0, belonging to the corresponding received channel (40) from which the received quantity (INT) originates, the products of received quantities (INT) and the respective weighting factors are added and the resulting weighted received quantity sums are processed to determine the channel trigger threshold (THRch).

5. The method according to claim 4, characterized in that the weighting factors are predetermined and / or Positions, in particular distances, of the receiving elements (42) of the receiving channels (40) from which received quantities (INT) are provided, relative to the at least one receiving element (42) of the receiving channel (40) for which the channel trigger threshold (THRch) is to be determined, are used to specify the weighting factors.

6. Method according to one of the preceding claims, characterized in that the channel trigger threshold (THRch) is determined as the sum of a summand based on the provided received quantities (INT), in particular a weighted received quantity sum, and at least one further threshold, in particular a system noise threshold and / or an ambient radiation threshold.

7. Method according to one of the preceding claims, characterized in that at least a part of the provided received variables (INT) for determining the channel trigger threshold (THRch) for the at least one received channel (40) is used, which originate from received channels (40) whose receiving elements (42) are at most three receiving elements (42) away from the at least one receiving element (42) which belongs to the at least one received channel (40) for which the channel trigger threshold (THRch) is to be determined.

8. Method according to one of the preceding claims, characterized in that with the at least one receiving channel (40), for which the channel trigger threshold value 31 / 33 2023PF01464 (THRch) is determined, provided received quantities (INT) are not used for determining this channel trigger threshold (THRch).

9. Method according to one of the preceding claims, characterized in that the method for determining at least one trigger threshold value (THRch) is carried out using means of an image receiver (38), in particular an imager chip, which comprises at least the receiving elements (42) of the receiving channels (40).

10. Method according to one of the preceding claims, characterized in that the method for determining at least one trigger threshold value (THRch) for at least one receiving channel (40) of an active optical detection device (14), in particular a LiDAR system, is carried out and / or the method for determining at least one trigger threshold value (THRch) for at least one receiving channel (40) of a passive optical detection device (14), in particular a camera, is carried out. 1.

1. Method for operating a detection device (14), in particular an optical detection device (14) for a vehicle (10), with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) with which optical rays (32N, 32H, 44) are received, and with the receiving channels (40) received quantities (INT) are provided which characterize the energy of the optical rays (32N, 32H, 44) received with the respective at least one receiving element (42), characterized in that in the method for operating a detection device (14) a method according to one of claims 1 to 10 is carried out for determining at least one channel trigger threshold (THRch), which is applied to the received quantity (INT) provided by the corresponding receiving channel (40).provided that the received signal (INT) is above the at least one channel trigger threshold (THRch), the received signal (INT) is plotted as a detection.

12. Algorithm (50), in particular software algorithm (50), with which a procedure 32 / 33 2023PF01464 for determining at least one trigger threshold value (THRch) for at least one receiving channel (40) of an optical detection device (14), in particular an optical detection device (14) for a vehicle (10), with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44), characterized in that the algorithm (50) is designed for carrying out the method according to one of claims 1 to 10 for determining at least one trigger threshold value (THRch).

13. Image receiver (38), in particular an imager chip, for an optical detection device (14), in particular for an optical detection device (14) for a vehicle (10), with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44), wherein the image receiver (38) has means configured for carrying out a method for determining at least one trigger threshold value (THRch) for at least one of the receiving channels (40), characterized in that the image receiver (38) has means configured for carrying out the method according to one of claims 1 to 10 for determining at least one trigger threshold value (THRch).

14. Optical detection device (14), in particular an optical detection device (14) for a vehicle (10), with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44), wherein the optical detection device (14) has means configured for carrying out a method for determining at least one trigger threshold value (THRch) for at least one of the receiving channels (40), characterized in that the optical detection device (14) has means configured for carrying out the method according to claims 1 to 10 for determining at least one trigger threshold value (THRch).

15. Driver assistance system (12) with at least one optical detection device (14) with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44), wherein the driver assistance system (12) has means configured to carry out a method for determining at least one trigger threshold (THRch) for 33 / 33 2023PF01464 at least one of the receiving channels (40), characterized in that the driver assistance system (12) has means which are designed to carry out the inventive method according to one of claims 1 to 10 for determining at least one trigger threshold value (TH Reh).

16. Vehicle (10) with at least one optical detection device (14) with several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical beams (32N, 32H, 44), wherein the driver assistance system (12) has means configured for carrying out a method for determining at least one trigger threshold (THRch) for at least one of the receiving channels (40), characterized in that the vehicle (10) has means configured for carrying out the method according to the invention according to one of claims 1 to 10 for determining at least one trigger threshold (THRch).

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