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

Abstract

A procedure for determining at least one trigger threshold (THR) is required. ch ) for at least one receiving channel of an optical detection device, in particular an optical detection device for a vehicle, with multiple receiving channels. The receiving channels each have at least one receiving element for optical beams. The receiving channels are configured to provide received quantities (INT) that characterize the energy of the optical beams received by the respective at least one receiving element. The optical detection device is put into operation to receive optical beams. At least two of the receiving channels of the optical detection device provide respective received quantities (INT). For at least one of the receiving channels of the optical detection device, an associated channel trigger threshold (THR) is defined. ch) determined on the basis of the received quantities (INT) provided by the at least two receiving channels.

Description

Technical field

[0001] 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.

[0002] 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.

[0003] 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.

[0004] Furthermore, the invention relates to an image receiver, in particular an imager chip, for an optical detection device, in particular for 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 image receiver 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.

[0005] 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.

[0006] 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.

[0007] 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. State of the art

[0008] 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.

[0009] 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. Disclosure of the invention

[0010] The object of the invention is achieved in the method by putting the optical detection device into operation to receive optical rays, with at least two of the receiving channels of the optical detection device providing respective received quantities, For at least one of the receiving channels of the optical detection device, an associated channel trigger threshold is determined based on the received parameters provided by the at least two receiving channels.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] Each receiving channel has at least one optical receiving element. These elements serve as the input to the receiving channels for optical rays. The optical rays strike the receiving elements and are subsequently converted into quantities, particularly electrical signals, which can then be further processed. Advantageously, the optical rays can be converted into received quantities by the receiving elements. In this way, the received quantities can be processed directly.

[0017] 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.

[0018] 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.

[0019] "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.

[0020] 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 receiving channels with which optical rays (object rays) emanating from an object in the optical detection device's field of view can be received. The invention can be used with flash LiDAR systems and scanning LiDAR systems. Furthermore, the invention can be used with optical detection devices with one-dimensional receiving elements, which in particular have receiving elements arranged in rows, or with two-dimensional receiving elements, which have receiving elements arranged in a planar fashion, in particular in rows and columns.

[0021] 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.

[0022] 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.

[0023] 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).

[0024] The system noise is generated within the detection device, particularly within the receiving channels, in a manner that is not of further interest here.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Advantageously, the received signals via the receiving channels can exhibit an exponential or quadratic curve. In this way, physically typical curves can be used.

[0030] Instead of using reference measurements, the received parameters for determining at least one trigger threshold can also be determined during the regular operation of the optical detection device. This eliminates the need for a separate reference measurement.

[0031] 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.

[0032] 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 in 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.

[0033] 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.

[0034] In a further advantageous embodiment of the method, the provided received signals can be weighted depending on the relationship between the receiving channels with which they are provided and the at least one receiving channel for which the channel trigger threshold is determined. In particular, the provided received signals can be weighted depending on the relative position, especially 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, the influence of crosstalk effects of the received signals from 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] In a further advantageous design of the procedure, the weighting factors are specified and / or 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.

[0039] Advantageously, the weighting factors can be predefined. This makes the weighting factors readily available.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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. This allows the channel trigger thresholds to be set even more precisely. Thus, a greater dynamic range with respect to the energy of received optical object rays can be captured.

[0044] 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 THR can be ch,x calculated according to the following formula, where the three nearest neighbors of the receiving element of the receiving channel for which the channel trigger threshold THR is used. ch,x The following should be taken into account when calculating: THRch,x=THRrausch+THRUmg+ax−3×INTx−3+ax−2×INTx−2+ax−1×INTx−1+ax+1×INTx+1+ax+2×INTx+2+ax+3×INTx+3 where THR rausch the threshold for system noise, THR umg the threshold for ambient radiation, INT index the received signal strength of the receiving channel with the corresponding index and a index The weighting factor for the receiving channel with the corresponding index is given. X is the index for the receiving channel for which the channel trigger threshold is to be calculated.

[0045] In this way, the channel trigger threshold for a one-dimensional image receiver can be efficiently determined.

[0046] Alternatively, for a one-dimensional image receiver, the channel trigger threshold THR can be advantageously set. ch,x for each of the receive channels according to the following formula, where all receive channels are included except for the receive channel for which the channel trigger threshold THR is set. ch,x The following should be taken into account when calculating: THRch,x=THRrausch+THRUmg+∑i=1nai×INTi where THR rausch the threshold for system noise, THR umg the threshold for ambient radiation, INT i The received signal strength of the receiving channel with the corresponding index i and ai are 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 THR is set.ch,x to be calculated. For the receive channel x, for which the channel trigger threshold THR ch,x The weighting factor a is to be calculated. x A value of 0 is specified. This means that the corresponding received value is not taken into account.

[0047] 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 THR can be ch,x,y for each of the receive channels according to the following formula, where all receive channels are included except for the receive channel for which the channel trigger threshold THR is set. ch,x,y The following should be taken into account when calculating: THRch,x,y=THRrausch+THRumg+∑i=1n∑j=1mai,j×INTi,j where THR rausch the threshold for system noise, THR umg the threshold for ambient radiation, INT i,jthe received signal strength of the receiving channel with the corresponding indices i, j and a i,j The weighting factor for the receive channel is represented by the corresponding indices i and j. Furthermore, i is the running index for the columns containing the receive elements of the receive channels, j is the running index for the rows of the receive channels, and x and y are the indices for the rows and columns containing the receive element of the receive channel for which the channel trigger threshold THR is located. ch,x to be calculated, is located. For the receive channel x, y, for which the channel trigger threshold THR is set. ch,x,y The weighting factor a is to be calculated. x,y A value of 0 is specified. This means that the corresponding received value is not taken into account.

[0048] 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.

[0049] 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.

[0050] 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 from 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.

[0051] In a further advantageous design of the process, 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, is carried out and / or the procedure for determining at least one trigger threshold for at least a receiving channel of a passive optical detection device, in particular a camera.

[0052] 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.

[0053] 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.

[0054] Furthermore, the object of the invention is solved in the method for operating a detection device by the fact that in the method for operating a detection device, a method according to the invention for determining at least one channel trigger threshold is carried out, at least one channel trigger threshold is applied to the received quantity provided by the corresponding receiving channel, provided that the received signal is above the at least one channel trigger threshold, the received signal is plotted as a detection.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Advantageously, the algorithm can be stored in the detection device. In this way, the procedure can be carried out directly in the detection device.

[0060] Advantageously, the algorithm can be implemented using software. This makes it easier to integrate the algorithm into the appropriate hardware.

[0061] Furthermore, the object of the invention is achieved 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Furthermore, the optical detection device can include means for processing the received signals and comparing them with the respective channel trigger thresholds. This allows received signals to be validated as object detections directly within the optical detection device. Additionally, object information such as distances, velocities, and / or directions of detected objects can be determined.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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, and in particular, its driving safety.

[0072] 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.

[0073] The at least one optical detection device allows monitoring areas inside and / or outside the vehicle 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.

[0074] 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.

[0075] Furthermore, the features and advantages identified in connection with the inventive method for determining at least one trigger threshold, the inventive method for operating a detection device, the inventive algorithm, the inventive image receiver, the inventive optical detection device, the inventive driver assistance system, and the inventive vehicle and their respective advantageous embodiments apply mutatis mutandis 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. Brief description of the drawings

[0076] 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 Fig. 1 a vehicle with a driver assistance system which has an optical detection device with which an object in front of the vehicle in the direction of travel can be detected; Fig. 2 a sequence of received variables that are obtained from the object during detection Fig. 1. When operating the detection device, the received parameters are provided with its receiving channels, wherein the received parameters characterize the energy of the optical rays coming from the object; Fig. 3 a progression of the channel trigger thresholds for the receiving channels, which are determined from the received parameters of the respective adjacent receiving channels; Fig. 4 a method for operating the detection device from the Fig. 1.

[0077] In the figures, identical components are labelled with the same reference symbols. embodiment(s) of the invention

[0078] In Fig. Figure 1 shows a vehicle 10 in a top view. The vehicle 10 includes a driver assistance system 12. With the help of the driver assistance system 12, functions of the vehicle 10, for example driving functions, can be controlled autonomously or semi-autonomously.

[0079] The driver assistance system 12 comprises an optical detection device 14 and a control unit 16.

[0080] 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 the Fig. Figure 1 shows an object 20 in the form of a street sign as an 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 towards the monitoring area 18.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] The detection device 14 can, for example, be configured 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.

[0086] The transmitter 24 is connected to the control and evaluation unit 28. The transmitter 24 can be controlled by the control and evaluation unit 28 in coordination with the receiver 26.

[0087] If the optical scanning rays 30 strike an object 20, they are reflected. For the sake of simplicity, the scanning rays 30 reflected from the object 20 will be referred to below as object rays 32. H and 32 N designated.

[0088] 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 energy in the Fig. The object 20 shown, 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 32 reflected by the retroreflective surface 34 H is significantly greater than the energy of the object rays reflected by the normally reflecting surfaces 36 32 H .

[0089] The object rays 32 N and 32 H , which are reflected towards the receiving device in the direction of the detection device 14, can be received by the receiving device 26.

[0090] The receiving device 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, the following are shown in the Fig. Only a few of the 40 receiving channels are indicated. An alternative image receiver chip can also have more or fewer than 100 40 receiving channels.

[0091] 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.

[0092] The receiving elements 42 allow the optical object rays 32 to be received.N and 32 H are converted into electrical quantities. The electrical quantities can be processed into received quantities INT using appropriate means. In the image receiver chip 38 used, the processing means are part of the received channels 40. The received quantities 44 characterize the energy of the object rays 32 received by the respective received channels 40. N or 32 H .

[0093] It can happen that a receiving element 42 is exposed to both strong object rays 32 H as well as from weak object rays 32 N Therefore, the respective index H or N is omitted from the reference symbol for the received quantities INT.

[0094] 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 be spatially horizontal and the columns spatially vertical. In this way, a two-dimensional image of the monitored area 18 can be obtained with the two-dimensional image receiver chip 38.

[0095] In addition to the object rays, the receiving channels 40 are used to receive 32 additional signals. N and 32 H The system also receives ambient optical radiation 44, if present, which strikes the respective receiving elements 42. The energy of the ambient radiation 44 is additionally incorporated into 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.

[0096] Provided that strong optical object rays 32 HWhen a receiving element 42 of a receiving channel 40 strikes a receiving element 42, this can cause crosstalk effects on adjacent receiving channels 40. The crosstalk effects lead to the reception of quantities INT from receiving channels 40 whose receiving elements 42 are affected by weaker object rays 32. N are affected, which distorts the crosstalk effects.

[0097] In Fig. Figure 2 shows, as an example, the curve 46 of the received parameters INT for channels 1 to 100, which resulted from a measurement at the device in the Fig. The object 20 shown is located directly in front of the detection device 14. The axis for the channels 44 is labelled CH. For easier orientation, object 20 is indicated above the path 46. The ideal path 46 is shown for comparison only. id The received parameters INT are shown as dashed lines, assuming no crosstalk effects occur. The curve 46 of the received parameters INT is shown in Fig. Figure 1 is shown as a curve. In reality, the received variables INT are discrete values ​​assigned to the respective receiving channels 40. The curve shown is the envelope for the received variables INT.

[0098] For the receiving channels 40, which are supplied by weaker object rays 32 N If the device is hit, crosstalk effects lead to measurement errors of 52. The measurement errors of 52 are in the Fig. 2 with hatched areas between the measured course 46 and the ideal course 46 id hinted at.

[0099] In the Fig. Point 2 is an example of the maximum received INT values. H,max , which are caused by strong object rays 32 HThe weak rays 32, originating from the center of the highly reflective surface 34 of the object 20, are caused by ambient rays 44 and system noise, for example in receive channel 40 numbered 50. The outer receive channels 40 numbered 1 and 100 are hardly affected by crosstalk effects. Thus, the received quantities INT there are at the level caused by the weak object rays 32, which come from the normally reflective surfaces 36, the ambient rays 44, and the system noise.

[0100] To correct the influence of crosstalk effects, ambient radiation 44 and system noise, an individual channel trigger threshold THR is set for each receiving channel 40. ch determined. The channel trigger threshold THR ch specifies the value of the received quantity INT, from which the reception of optical object rays 32 N or 32 H, which originate from the object 20 in the field of view 22 of the detection device 14, is detected. When optical object rays 32 N or 32 H If detected, this will be recorded as detections of object 20.

[0101] The respective channel trigger threshold THR ch is chosen such that it lies above a value for a received quantity INT that is caused exclusively by ambient radiation 44 and the signal noise. Received quantities INT that are below the channel trigger threshold THR ch lying, are not considered to be from object rays 32 N or 32 H originating from, i.e., originating from an object 20, processed.

[0102] The image receiver chip 38 has a processor 48. The processor 48 comprises a [missing information] in the Fig. 4 indicated algorithm 50, with which the channel trigger thresholds THR chThey can be determined. Algorithm 50 is implemented as a software program.

[0103] Fig. Figure 3 shows the curve 54 for the channel trigger thresholds THR. ch , which are for the course 46 of the received variables INT from Fig. 2 results. The curve 54 for the channel trigger thresholds THR ch is similar to the curve 46 for the received parameters INT from the Fig. 2. The curve 54 reaches its maximum at receiving channel 40, numbered 50. There, the influence of crosstalk effects from neighboring receiving channels 40, which are caused by strong object rays 32, is H The minima of the curve 54 are located at receiving channels 40 numbered 1 and 100. There, the influence of crosstalk effects from neighboring receiving channels 40, caused by strong object rays 32, is greatest. H to be hit, at the smallest.

[0104] The trend of channel trigger thresholds THR 54 ch is in Fig. 3 is shown as a curve. In reality, the channel trigger thresholds are THR. ch The discrete values ​​are assigned to the respective receiving channels 40. The curve shown is the envelope for the channel trigger thresholds THR. ch .

[0105] Fig. Figure 4 shows a method for operating the detection device 14. The method includes a procedure for determining the channel trigger thresholds THR. ch for the receiving channels 40 of the detection device 14.

[0106] First, in step 56, a measurement is performed with 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 used to receive optical beams, specifically the optical object beams 32.N and 32 H , put into operation.

[0107] 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 32. N or 32 H , and the optical ambient rays 44, which are received with the corresponding receiving channels 40. Furthermore, the signal noise is included in the received quantities INT.

[0108] In step 60, the corresponding channel trigger threshold THR is set for each of the receive channels 40. ch determined 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 THR ch is determined.

[0109] 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 THR is set, are determined. ch,x The calculation is to be carried out in consideration. Algorithm 50 is as follows: THRch,x=THRrausch+THRUmg+ax−3×INTx−3+ax−2×INTx−2+ax−1×INTx−1+ax+1×INTx+1+ax+2×INTx+2+ax+3×INTx+3

[0110] THR is involved rausch The threshold for system noise. THR umg The threshold for ambient radiation is 44. INT x-3 , INT x-2 , INT x-1 , INT x+1 , INT x+2 and INT x+3 are the received signal strength of the adjacent receiving channels 40. a x-3 , a x-2 , a x-1 , a x+1 , a x+2 and a x+3The weighting factors for the corresponding receive channels 40 are given. The index x denotes the receive channel 40 for which the channel trigger threshold THR is set. ch,x to be calculated.

[0111] The weighting factors a x-3 , a x-2 , a x-1 , a x+1 , a x+2 and a x+3 For example, spatial positions of the respective receiving elements 42 of the adjacent receiving channels 40 can be related to the receiving element 42 of the receiving channel 40 for which the channel trigger threshold THR ch is determined, included. The weighting factors a x-3 , a x-2 , a x-1 , a x+1 , a x+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.

[0112] If the receiving channels 40 do not have three neighboring receiving channels 40 on one side, the corresponding intensity values ​​INT are equal to 0.

[0113] 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 received 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 received quantity sums are used to determine the channel trigger threshold THR. ch with the threshold THR rausch for the system noise and the threshold THR umg The ambient radiation 44 was processed, namely summed up.

[0114] The determined individual channel trigger thresholds THR ch will be provided in step 62.

[0115] In step 64, the respective channel trigger thresholds THR are set. ch The system applies to the received parameters INT provided by the corresponding receive channel 40. Specifically, it applies those received parameters INT that exceed the corresponding channel trigger threshold THR. ch lie, marked as detections.

[0116] 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.

[0117] In step 72, the point cloud 68 is transmitted to the control unit 16.

[0118] Steps 64 to 68 can be performed in the control and evaluation unit 28.

[0119] In an alternative algorithm 50, instead of only considering 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 considered, except for the received channel 40 for which the channel trigger threshold THR ch,x The calculation is to be performed using the following algorithm 50: THRch,x=THRrausch+THRUmg+∑i=1nai×INTi

[0120] THR is involved rausch The threshold for system noise. THR umg is the threshold value for ambient radiation. The index i denotes the individual receiving channels. 40. INT i The received parameters of the receive channels 40 with the corresponding index i are . 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 THR is set. ch,xto be calculated. Since a receive channel 40 has no crosstalk effect on itself, the receive channel 40 with the index x, for which the channel trigger threshold THR is set, is assigned the value. ch,x The weighting factor a is to be calculated. x = 0 is specified. This causes the corresponding received variable INT to be used. x is not taken into account.

[0121] 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 ch,x,y The number 50 can be determined according to the following algorithm: THRch,x,y=THRrausch+THRumg+∑i=1n∑j=1mai,j×INTi,j

[0122] THR is involved rausch The threshold for system noise. THR umgis the threshold for the ambient radiation. "n" is the number of rows of the image receiver chip 38. "m" is the number of columns of the image receiver chip 38. "i" is the running index for the rows in which the receiving elements of the receiving channels are located. "j" is the running index for the columns of the receiving channels. The index x denotes the row and the index y the column in which the receiving element 42 of receiving channel 40 is located, for which the channel trigger threshold THR is set. ch,x to be calculated. INT i,j is the received signal strength of receiving channel 40 in row i and column j. “a i,j “ is the weighting factor for receive channel 40 in row i and column j. For receive channel 40 with indices x, y, for which the channel trigger threshold THR ch,x,y The weighting factor a is to be calculated. x,y= 0 is specified. This means that the corresponding received parameter INT is not taken into account, since the received channel 40 cannot crosstalk onto itself. The other weighting factors a i,j include, for example, the relative position of the receiving elements 42 of the corresponding receiving channels 40 relative to the receiving element 42 of the receiving channel 40 for which the channel trigger threshold THR ch,x,y to be calculated.

[0123] Even with a two-dimensional image receiver chip 38, a THR can be used to calculate a respective channel trigger threshold. ch Instead of the received parameters INT of all other received channels 40, only the received parameters INT of a part of the other received channels 40, for example the three nearest received channels 40, are used. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 20200249326 A1

[0008]

Claims

[1] Methods for determining at least one trigger threshold (THR) ch ) 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 (32) N , 32 H , 44) and the receiving channels (40) are designed to provide received quantities (INT) which represent the energy of the optical rays (32) received by the respective at least one receiving element (42). N , 32 H , 44) characterize, characterized by , that the optical detection device (14) for receiving optical rays (32) N , 32 H , 44) is put into operation, with at least two of the receiving channels (40) of the optical detection device (14) respective received quantities (INT) are provided, for at least one of the receiving channels (40) of the optical detection device (14) an associated channel trigger threshold (THR) ch ) 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 by , that the provided received parameters (INT) are used to determine the channel trigger threshold (THR) ch ) for which at least one receiving channel (40) is weighted. [3] Method according to claim 2, characterized by , that the provided received quantities (INT) depend on a respective relationship of the received channels (40) with which they are provided to the at least one received channel (40) for which the channel trigger threshold (THR) ch) is determined, weighted, 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 (THR) ch ) is determined, weighted. [4] Method according to any of the preceding claims, characterized by , that 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 used to determine the channel trigger threshold (THR). ch ) are processed. [5] Method according to claim 4, characterized by 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 (THR) ch ) to be determined, to be used to specify the weighting factors. [6] Method according to any of the preceding claims, characterized by , that the channel trigger threshold (THR) ch ) 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 any of the preceding claims, characterized by, that at least a part of the provided received parameters (INT) can be used to determine the channel trigger threshold (THR) ch ) for which at least one receiving channel (40) is used, which originate from receiving 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 receiving channel (40) for which the channel trigger threshold (THR) ch ) is to be determined. [8] Method according to any of the preceding claims, characterized by , that with at least one receiving channel (40) for which the channel trigger threshold (THR) ch ) is determined, provided received quantities (INT) are not used for determining this channel trigger threshold (THR). ch ) be used. [9] Method according to any of the preceding claims, characterized by that the procedure for determining at least one trigger threshold (THR)ch ) is carried out by means of an image receiver (38), in particular an imager chip, which includes at least the receiving elements (42) of the receiving channels (40). [10] Method according to any of the preceding claims, characterized by that the procedure for determining at least one trigger threshold (THR) ch ) 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 procedure for determining at least one trigger threshold (THR) ch ) for at least one receiving channel (40) of a passive optical detection device (14), in particular a camera. [11] 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 (32) N , 32 H , 44) are received, and received quantities (INT) are provided with the receiving channels (40) which represent the energy of the optical rays (32) received with the respective at least one receiving element (42). N , 32 H , 44) characterize, characterized by , that in the method for operating a detection device (14) a method according to one of claims 1 to 10 for determining at least one channel trigger threshold (THR) ch ) is carried out, at least one channel trigger threshold (THR) ch) is applied to the received quantity (INT) provided by the corresponding received channel (40), provided that the received quantity (INT) is above the at least one channel trigger threshold (THR) ch ) is located, the received quantity (INT) is plotted as a detection. [12] Algorithm (50), in particular software algorithm (50), with which a method for determining at least one trigger threshold (THR) ch ) 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 (32) N , 32 H , 44) exhibit, characterized by, that the algorithm (50) is configured to carry out the method according to one of claims 1 to 10 for determining at least one trigger threshold (THR) ch ). [13] Image receiver (38), in particular 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 (32) N , 32 H , 44) wherein the image receiver (38) has means configured to carry out a method for determining at least one trigger threshold (THR) ch ) for at least one of the receiving channels (40), characterized by , that the image receiver (38) comprises means configured for carrying out the method according to one of claims 1 to 10 for determining at least one trigger threshold (THR) ch ). [14] Optical detection device (14), in particular 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 rays (32) N , 32 H , 44) wherein the optical detection device (14) comprises means configured to carry out a method for determining at least one trigger threshold (THR) ch ) for at least one of the receiving channels (40), characterized by , that the optical detection device (14) has means which are configured to carry out the method according to claims 1 to 10 for determining at least one trigger threshold value (THR) ch ). [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 (32) N , 32 H , 44) wherein the driver assistance system (12) includes means designed to carry out a procedure for determining at least one trigger threshold (THR) ch ) for at least one of the receiving channels (40), characterized by , that the driver assistance system (12) has means which are configured to carry out the method according to the invention as described in one of claims 1 to 10 for determining at least one trigger threshold (THR) ch ). [16] Vehicle (10) with at least one optical detection device (14) having several receiving channels (40), wherein the receiving channels (40) each have at least one receiving element (42) for optical rays (32) N , 32 H, 44) wherein the driver assistance system (12) includes means designed to carry out a procedure for determining at least one trigger threshold (THR) ch ) for at least one of the receiving channels (40), characterized by , that the vehicle (10) has means which are configured to carry out the inventive method according to one of claims 1 to 10 for determining at least one trigger threshold value (THR) ch ).

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