Exposure control of a camera of a vehicle

Abstract

According to a computer-implemented method for exposure control of a camera (4a, 4b, 4c, 4d) of a vehicle (1), a speed (6) of the vehicle (1) is received and an exposure profile is selected from at least two exposure profiles depending on the speed (6) of the vehicle (1), each of the at least two predefined exposure profiles comprising a respective mapping rule for mapping an image property to respective values of a set of exposure parameters of the camera (4a, 4b, 4c, 4d). The values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are adjusted according to the mapping rule of the selected exposure profile and depending on a target value of the image property.

Description

[0001] 2024PF01070

[0002] 1

[0003] Exposure control of a camera of a vehicle

[0004] The present invention is directed to a computer-implemented method for exposure control of a camera of a vehicle and to a method for guiding a vehicle at least in part automatically, wherein said computer-implemented is carried out. The invention is further directed to a data processing system for carrying out said computer-implemented method, to a camera system for a vehicle comprising said data processing system, to an electronic vehicle guidance system comprising said data processing system, and to corresponding computer program products.

[0005] It is known to adjust exposure parameters of a camera of a vehicle depending on properties of the current camera image. However, the way how the exposure parameters are adjusted in an optimal way may depend on the speed of the vehicle. In known camera systems, certain cameras, for example a front camera, of the vehicle are used for applications at high speed, for example adaptive cruise control etcetera, while other cameras of the vehicle, sometimes denoted as satellite cameras or surround-view cameras, are used for applications at low speed, for example parking assistance etcetera. The different cameras are controlled based on algorithms that are optimized for the respective speed domains.

[0006] It may be desirable, however, to use the same camera for different applications in different speed domains. In known systems, the image quality could be inferior in case the vehicle speed does not fall into the intended speed domain for the respective camera due to non- optimal exposure control.

[0007] It is an objective of the present invention to increase the robustness of the image quality of camera images of a camera of a vehicle for different speed domains.

[0008] This objective is achieved by the subject matter of the independent claim. Further implementations and preferred embodiments are subject matter of the dependent claims.

[0009] The invention is based on the idea to use different exposure profiles for different speeds of the vehicle, each exposure profile comprising a respective mapping rule for mapping an image property to respective values of a set of exposure parameters of the camera. 2024PF01070

[0010] 2

[0011] According to an aspect of the invention, a computer-implemented method for exposure control of a camera of a vehicle, in particular a motor vehicle, for example a car, a van, a truck, a motorcycle etcetera, is provided. Therein, a speed of the vehicle is received, in particular from a speed sensor of the vehicle, and an exposure profile is selected from at least two predefined exposure profiles depending on the speed of the vehicle. Each exposure profile of the at least two predefined exposure profiles comprises a respective mapping rule for mapping an image property to respective values of a set of exposure parameters of the camera. The values of the set of exposure parameters of the camera are adjusted according to the mapping rule of the selected exposure profile and depending on a predefined target value of the image property.

[0012] Unless stated otherwise, all steps of the computer-implemented method may be performed by a data processing system, which comprises at least one data processing device, in particular a data processing system of the vehicle. In particular, the at least one data processing device is configured or adapted to perform the steps of the computer- implemented method. For this purpose, the at least one data processing device may for example store a computer program comprising instructions which, when executed by the at least one data processing device, cause the at least one data processing device to carry out the computer-implemented method. The terms "data processing system" and "at least one data processing device" may be used interchangeably.

[0013] All data processing devices of the at least one data processing device may be comprised by the vehicle. However, it is also possible that all data processing devices of the at least one data processing device are part of an external computing system external to the vehicle, for example a mobile electronic device, a backend server or a cloud computing system. It is also possible that the at least one data processing device comprises at least one vehicle data processing device of the vehicle as well as at least one external data processing device comprised by the external computing system. The at least one vehicle data processing device may for example be comprised by one or more electronic control units, ECUs, and / or one or more zone control units, ZCUs, and / or one or more domain control units, DCUs, of the vehicle and / or by the camera.

[0014] In case the at least one data processing device comprises two or more data processing devices, certain steps carried out by the at least one data processing device may be understood such that different data processing devices carry out different steps or different parts of a step. In particular, it is not required that each data processing device 2024PF01070

[0015] 3 carries out the steps completely. In other words, carrying out the steps may be distributed amongst the two or more data processing devices.

[0016] From each implementation of the computer-implemented method, a respective implementation of a method for exposure control of a camera of a vehicle, which is not purely computer-implemented, is obtained by including respective steps of generating the camera image by the camera and / or steps of generating a further camera image according to the adjusted values of the set of exposure parameters by the camera.

[0017] The camera image represents an environment of the vehicle, in particular an outer environment of the vehicle.

[0018] The mapping rules of different exposure profiles may be different from each other and, in general, are different from each other. However, in particular, the mapping rule of each exposure profile maps the same image property or the value of the image property, respectively, to values of the same set of exposure parameters.

[0019] The at least two exposure profile are, in particular, stored in a computer readable manner, for example on a storage device of the data processing system.

[0020] The set of exposure parameters comprises one or more exposure parameters. An exposure parameter may be understood as a parameter of the camera, for example an imager of the camera and / or an image signal processor, ISP, of the camera etcetera, which affects, for a given light intensity hitting the imager or a certain pixel of the imager, the output intensity of the camera image or the respective pixel. The set of exposure parameters may for example comprise an exposure time, also denoted as integration time, and / or one or more gain values of the camera.

[0021] The image property may be an image intensity or image brightness, in particular an overall image intensity or overall image brightness. The image intensity or image brightness is, per definition, affected by the value of the exposure parameters. In some embodiments, however, the image property is given by another property of the respective image, for example a noise level, in particular a signal-to-noise ratio, or the like.

[0022] The camera image may be obtained directly from the camera or from a buffer storage or the like. In particular, the camera image may correspond to a frame of a camera image stream generated by the camera. 2024PF01070

[0023] 4

[0024] By means of the computer-implemented method according to the invention, an optimal exposure profile, in particular an optimal mapping rule, may be provided for different speeds of the vehicle. Consequently, the target value of the image property may be achieved at different speeds of the vehicle with increased reliability.

[0025] Given the target value of the image property and the selected exposure profile, the values of the set of exposure parameters may be set directly or with a time-delay and / or successively over a certain number of frames to the values assigned to the target value of the image property by the mapping rule of the selected exposure profile. This is done in some embodiments of the computer-implemented method. In other embodiments, however, this is not necessarily the case, as will be explained further below.

[0026] According to several embodiments, the at least two predefined exposure profiles consist of a first exposure profile and a second exposure profile. The first exposure profile is selected if the speed of the vehicle is less than a predefined threshold speed and the second exposure profile is selected if the speed of the vehicle is greater than the threshold speed. In case the speed of the vehicle is equal to the threshold speed, the first exposure profile is selected in some embodiments and the second exposure profile is selected in other embodiments.

[0027] The threshold speed may for example lie in the range [20 km / h, 50 km / h], in particular in the range [30 km / h, 40 km / h].

[0028] It is emphasized, however, that the at least two predefined exposure profiles may comprise three or more exposure profiles in other embodiments.

[0029] According to several embodiments, the value of the image property is determined for a camera image of the camera. The values of the set of exposure parameters of the camera are adjusted according to the mapping rule of the selected exposure profile and depending on a deviation of the value of the image property of the camera image from the target value of the image property.

[0030] In particular, by taking into account the deviation of the value of the image property of the camera image from the target value of the image property, a smooth transition between different values of the set of exposure parameters may be achieved. 2024PF01070

[0031] 5

[0032] The value of the image property of the camera image is for example determined and compared to the target value of the image property. The deviation of the value of the image property of the camera image from the predefined target value of the image property is, in particular, determined based on the result of the comparison.

[0033] According to several embodiments, each exposure profile of the at least two predefined exposure profiles comprises or is associated with a plurality of bins for the value of the image property. The respective mapping rule assigns respective values of the set of exposure parameters to each bin of the plurality of bins. Each exposure profile of the at least two predefined exposure profiles comprises at least one transition rule for a transition between bins of the respective plurality of bins. The values of the set of exposure parameters of the camera are adjusted according to the at least one transition rule of the selected exposure profile.

[0034] Therein, a bin can be understood as an interval of values of the image property. All bins of the plurality of bins together cover a predefined total value range of the image property. In particular, the bins of the plurality of bins are non-overlapping. The respective mapping rule maps the same values of the set of exposure parameters to all values of the image property, which lie in the same bin. Consequently, the adjustment of the set of exposure parameters may comprise a transition from one bin to another bin depending on the target value of the image property, in particular, depending on the deviation of the value of the image property of the camera image from the target value of the image property. The transition rule specifies, in particular, one or more boundary conditions for said transition from one bin to the other bin.

[0035] For example, the total value range of the image property may be the same for all exposure profiles after at least two exposure profiles. On the other hand, the number of bins and / or the division of the total value range into the plurality of bins may, in some embodiments, be different for different exposure profiles.

[0036] In some embodiments, the transition rules may differ for different exposure profiles after at least two exposure profiles. In particular, a first exposure profile may comprise a first transition rule and a second exposure profile may comprise a second transition rule, which is different from the first transition rule.

[0037] In particular, by limiting the transition in terms of the transition rules, a smooth transition between different values of the set of exposure parameters may be achieved. 2024PF01070

[0038] 6

[0039] According to several embodiments, a current bin of the plurality of bins of the selected exposure profile is determined according to the value of the image property of the camera image. A target bin of the plurality of bins of the selected exposure profile is determined according to the target value of the image property. Depending on the at least one transition rule of the selected exposure profile, the values of the set of exposure parameters of the camera are set to one of the following: i) the values of the set of exposure parameters assigned to the target bin by the mapping rule of the selected exposure profile, ii) the values of the set of exposure parameters assigned to the current bin by the mapping rule of the selected exposure profile, iii) the values of the set of exposure parameters assigned to an intermediate bin between the current bin and the target bin by the mapping rule of the selected exposure profile.

[0040] The bins of the plurality of bins correspond to certain value ranges as described above. Consequently, they can be ordered from a range with the lowest values of the image property to a range with the highest value of the image property in the total value range. In this sense, the intermediate bin can be understood. In particular, the range associated to the intermediate bin lies between the respective ranges of the current bin and target bin.

[0041] In particular, the deviation of the value of the image property of the camera image from the target value of the image property may be a bin deviation of the current bin from the target bin or the bin deviation may be determined based on the deviation of the value of the image property of the camera image from the target value of the image property or based on the value of the image property of the camera image and the target value of the image property.

[0042] For example, the values of the set of exposure parameters of the camera are set to one of the options i), ii) and iii) depending on the transition rule of the selected exposure profile and the bin deviation.

[0043] In particular, in case of option i), the values of the set of exposure parameters are changed to a maximum extent and, consequently, the target value of the image property is achieved in very short time. In case of option ii), the values of the set of exposure parameters remain unchanged. Thus, unnecessary adjustments may be avoided, in particular, if the deviation of the value of the image property of the camera image from the target value of the image property is relatively small. In case of option iii), the values of the 2024PF01070

[0044] 7 set of exposure parameters are changed, but not to the maximum extent. Consequently, too strong adjustments in a single step may be avoided, in particular, if the deviation of the value of the image property of the camera image from the target value of the image property is relatively large.

[0045] According to several embodiments, the values of the set of exposure parameters of the camera are set to the values of the set of exposure parameters assigned to the current bin by the mapping rule of the selected exposure profile, if the deviation of the value of the image property of the camera image from the target value of the image property is less than a predefined tolerance value. This is, in particular, specified by the transition rule of the selected exposure profile.

[0046] In other words, option ii) is chosen in this case. In particular, the values of the set of exposure parameters are not changed in this case. Thus, unnecessary adjustments are avoided, if the deviation of the value of the image property of the camera image from the target value of the image property is relatively small.

[0047] The tolerance value may, in some embodiments, be the same for all bins and for all exposure profiles. In other embodiments, the tolerance value may be the same for all bins of a given exposure profile but differ for different exposure profiles. In yet other embodiments, the tolerance value may differ for different bins of a given exposure profile.

[0048] According to several embodiments, the values of the set of exposure parameters of the camera are set to the values of the set of exposure parameters assigned to the target bin by the mapping rule of the selected exposure profile only if a number of bins lying between the current bin and the target bin is equal to or less than a predefined maximum step width. This is, in particular, specified by the transition rule of the selected exposure profile.

[0049] In other words, option i) is chosen in this case. In particular, the values of the set of exposure parameters are changed to a maximum extent and, consequently, the target value of the image property is achieved in very short time.

[0050] The maximum step width may be zero or a natural number greater than zero. If the maximum step width is equal to zero, then option i) is only chosen if the current bin and the target bin lie next to each other. 2024PF01070

[0051] 8

[0052] According to several embodiments, if the number of bins lying between the current bin and the target bin is greater than a predefined maximum step width, the values of the set of exposure parameters of the camera are set to the values of the set of exposure parameters assigned to the intermediate bin by the mapping rule of the selected exposure profile. This is, in particular, specified by the transition rule of the selected exposure profile.

[0053] In particular, the maximum step width is equal to one or larger in this case. In other words, option ill) is chosen in this case. In particular, the values of the set of exposure parameters are changed in such a case but not to the maximum extent. Consequently, too strong adjustments in a single step may be avoided, in particular, if the deviation of the value of the image property of the camera image from the target value of the image property is relatively large.

[0054] It is noted that in case option ill) is chosen, the values of the set of exposure parameters may be adjusted again in one or more further cycles, in particular until the target bin is reached.

[0055] According to several embodiments, the number of bins lying between the current bin and the intermediate bin is equal to the maximum step width.

[0056] Consequently, the values of the set of exposure parameters are changed as much as allowed by the respective transition rule. Consequently, a fast effective change of the exposure parameters is achieved.

[0057] According to several embodiments, the set of exposure parameters comprises an exposure time.

[0058] The exposure time is of high relevance for the image quality and, in particular, for the image intensity or image brightness. The exposure time is, in fact, one of the most important exposure parameters of a camera. Thus, adjusting the exposure time is particularly efficient to reach the target image property.

[0059] According to several embodiments, the set of exposure parameters comprises an analog gain and / or a digital gain of the camera. 2024PF01070

[0060] 9

[0061] The analog gain is a gain which is applied before the raw pixel values of the imager are converted into digital values. In other words, the analog gain increases the raw pixel values before the analog-to-digital conversion. The digital gain, on the other hand, increases the digitized pixel values.

[0062] The analog gain and the digital gain are of high relevance for the image quality and, in particular, for the image intensity or image brightness. Thus, adjusting the analog gain and / or the digital gain is particularly efficient to reach the target image property.

[0063] According to several embodiments, the set of exposure parameters comprises a color gain of the camera.

[0064] While the analog gain and the digital gain affect pixels or sub pixels equally irrespective of their color, in particular a color filter arranged above them, the color gain is a relative gain between differently colored pixels. It may be defined for all colors in the respective pixel array, wherein for one of the colors, the color gain may also be equal to one per definition.

[0065] Adjusting the color gain allows to reach the target image property without significantly changing the color impression of resulting image.

[0066] According to several embodiments, the image property is given by or depends on an image intensity.

[0067] The image intensity depends, in particular, on the pixel values of the individual pixels of the camera image. In some embodiments, the image intensity may correspond to the sum or a weighted sum of the pixel values of all pixels of the camera image.

[0068] According to several embodiments, the camera image is divided into a plurality of cells. A cell intensity is determined for each cell of the plurality of cells depending on respective pixel values of the camera image in the respective cell. The image intensity is determined as a weighted sum of the cell intensities for the plurality of cells.

[0069] In this way, more important regions of the camera, for example in the center of the camera image, may be given more impact on the exposure control.

[0070] How the camera image is divided into the plurality of cells may be identical for all exposure profiles or may differ for different exposure profiles. 2024PF01070

[0071] 10

[0072] A weighted sum is, in particular, computed according to a predefined set of weighting factors including a respective weighting factor for each cell. The weighting factors may differ for different exposure profiles or may be independent of the exposure profiles.

[0073] For a given cell, the cell intensity may be computed as a sum or a weighted sum of the respective pixel values in the respective cell. The corresponding weighting factors may, for example, depend on the digital gain and / or analog gain and / or color gain and / or exposure time used for the respective pixel of the camera image, prior to the adjustment of the values of the set of exposure parameters.

[0074] According to several embodiments, the camera is controlled to capture a further camera image according to the adjusted values of the set of exposure parameters.

[0075] According to a further aspect of the invention, a method for guiding a vehicle at least in part automatically, wherein a computer-implemented method according to the invention is carried out, is provided. At least one control signal for guiding the vehicle at least in part automatically is generated depending on the camera image and / or depending on the further camera image, for example by a control system of the vehicle or of the data processing system. Alternatively or in addition, driver assistance information for assisting a driver at guiding the vehicle is generated depending on the camera image and / or depending on the further camera image, in particular by the control system.

[0076] The at least one control signal may for example be provided to one or more actuators of the vehicle, including for example one or more braking actuators and / or one or more steering actuators and / or one or more propulsion motors of the vehicle. The one or more actuators may affect a longitudinal and / or lateral control of the vehicle in order to guide the vehicle at least in part automatically based on the at least one control signal.

[0077] The assistance information may be output by means of an output device of the vehicle, for example a display and / or an audio output system and / or a haptic output system.

[0078] For use cases or use situations which may arise in a computer-implemented method or a method according to the invention and which are not explicitly described herein, it may be provided that, in accordance with the computer-implemented method or the method according to the invention, respectively, an error message and / or a prompt for user feedback is output and / or a default setting and / or a predetermined initial state is set. 2024PF01070

[0079] 11

[0080] According to a further aspect of the invention, a data processing system is provided, which is configured to carry out a computer-implemented method according to the invention.

[0081] The terms "data processing system" and "at least one data processing device" may be used interchangeably in the present disclosure. In the present disclosure, a data processing device, also denoted as computing device, may for example be understood as a device with processing circuitry for processing data. A data processing device can therefore perform computing operations in order to process data. An indexed access to a data structure, for example a look-up table, LUT, or a database may also be considered as a computing operation. Data processing that is partially or fully implemented in hardware can also be considered a computing operation.

[0082] In particular, a data processing device may include one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits, ASIC, one or more field-programmable gate arrays, FPGA, and / or one or more systems-on-a-chip, SoC. A data processing device may also include one or more processors, for example one or more microprocessors, one or more central processing units, CPU, one or more graphics processing units, GPU, and / or one or more signal processors, in particular one or more digital signal processors, DSP. The data processing device may also include a physical or a virtual cluster of computers or other of said devices.

[0083] A data processing device may also comprise one or more hardware and / or software interfaces, for example for receiving and / or providing data, respectively.

[0084] A data processing device may also comprise one or more memory devices. Therein, a memory device may be implemented as a volatile memory, for example a dynamic random access memory, DRAM, or a static random access memory, SRAM, or as a nonvolatile data memory, for example a read-only memory, ROM, a programmable read-only memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, a flash memory or flash EEPROM, a ferroelectric random access memory, FRAM, a magnetoresistive random access memory, MRAM, or a phase-change random access memory, PCRAM. 2024PF01070

[0085] 12

[0086] According to a further aspect of the invention, a camera system for a vehicle is provided. The camera system comprises a data processing system according to the invention and the camera.

[0087] According to a further aspect of the invention, an electronic vehicle guidance system for a vehicle is provided. The electronic vehicle guidance system comprises a data processing system according to the invention or a camera system according to the invention. The electronic vehicle guidance system comprises a control system, which is configured to generate at least one control signal for guiding the vehicle at least in part automatically depending on the further camera image and / or to generate driver assistance information for assisting a driver at guiding the vehicle depending on the further camera image.

[0088] The control system may be part of the data processing system or part of a further data processing system.

[0089] An electronic vehicle guidance system may be understood as an electronic system configured to guide a vehicle in a fully automated or a fully autonomous manner and, in particular, without a manual intervention or control by a driver or user of the vehicle being necessary. The vehicle carries out all required functions, such as steering maneuvers, deceleration maneuvers and / or acceleration maneuvers as well as monitoring and recording the road traffic and corresponding reactions automatically. In particular, the electronic vehicle guidance system may implement a fully automatic or fully autonomous driving mode according to level 5 of the SAE J3016 classification. An electronic vehicle guidance system may also be implemented as an advanced driver assistance system, ADAS, assisting a driver for partially automatic or partially autonomous driving. In particular, the electronic vehicle guidance system may implement a partly automatic or partly autonomous driving mode according to levels 1 to 4 of the SAE J3016 classification. Here and in the following, SAE J3016 refers to the respective standard dated April 2021 .

[0090] Guiding the vehicle at least in part automatically may therefore comprise guiding the vehicle according to a fully automatic or fully autonomous driving mode according to level 5 of the SAE J3016 classification. Guiding the vehicle at least in part automatically may also comprise guiding the vehicle according to a partly automatic or partly autonomous driving mode according to levels 1 to 4 of the SAE J3016 classification.

[0091] Further embodiments of the electronic vehicle guidance system according to the invention follow directly from the various embodiments of the computer-implemented method or the 2024PF01070

[0092] 13 method for guiding a vehicle according to the invention and vice versa. In particular, individual features and corresponding explanations as well as advantages relating to the various embodiments of the computer-implemented method or the method for guiding a vehicle according to the invention can be transferred analogously to corresponding embodiments of the electronic vehicle guidance system according to the invention. In particular, the electronic vehicle guidance system according to the invention is designed or programmed to carry out the computer-implemented method or the method for guiding a vehicle according to the invention. In particular, the electronic vehicle guidance system according to the invention carries out the computer-implemented method or the method for guiding a vehicle according to the invention.

[0093] According to a further aspect of the invention, a computer program comprising instructions is provided. When the instructions are executed by a data processing system, the instructions cause the data processing system to carry out a computer-implemented method according to the invention.

[0094] The instructions may be provided as program code, for example. The program code can for example be provided as binary code or assembler and / or as source code of a programming language, for example C, and / or as program script, for example Python.

[0095] According to a further aspect of the invention, a further computer program comprising further instructions is provided. When the further instructions are executed by an electronic vehicle guidance system according to the invention, in particular by the data processing system of the electronic vehicle guidance system, the further instructions cause the electronic vehicle guidance system to carry out a method for guiding a vehicle at least in part automatically according to the invention.

[0096] The further instructions may be provided as program code, for example. The program code can for example be provided as binary code or assembler and / or as source code of a programming language, for example C, and / or as program script, for example Python.

[0097] According to a further aspect of the invention, a computer-readable storage medium storing a computer program and / or a further computer program according to the invention is provided. 2024PF01070

[0098] 14

[0099] The computer program, the further computer program and the computer-readable storage medium are respective computer program products comprising the instructions and / or the further instructions.

[0100] Further features of the invention are apparent from the claims, the figures and the figure description. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of figures and / or shown in the figures may be comprised by the invention not only in the respective combination stated, but also in other combinations. In particular, embodiments and combinations of features, which do not have all the features of an originally formulated claim, may also be comprised by the invention. Moreover, embodiments and combinations of features, which go beyond or deviate from the combinations of features set forth in the recitations of the claims may be comprised by the invention.

[0101] In the following, the invention will be explained in detail with reference to specific exemplary implementations and respective schematic drawings. In the drawings, identical or functionally identical elements may be denoted by the same reference signs. The description of identical or functionally identical elements is not necessarily repeated with respect to different figures.

[0102] In the figures,

[0103] Fig. 1 shows schematically a vehicle with an exemplary embodiment of a camera system according to the invention;

[0104] Fig. 2 shows a schematic flow diagram of an exemplary embodiment of a computer- implemented method for exposure control of a camera of a vehicle according to the invention;

[0105] Fig. 3 shows a schematic flow diagram of a further exemplary embodiment of a computer-implemented method for exposure control of a camera of a vehicle according to the invention;

[0106] Fig. 4 shows a schematic flow diagram of a further exemplary embodiment of a computer-implemented method for exposure control of a camera of a vehicle according to the invention. 2024PF01070

[0107] 15

[0108] Fig. 1 shows schematically a vehicle 1 with an exemplary embodiment of a camera system 2 according to the invention. The camera system 2 comprises a data processing system 3 according to the invention and a camera 4a, 4b, 4c, 4d for the vehicle 1 .

[0109] The data processing system 3 is configured to carry out a computer-implemented method for exposure control according to the invention in order to adjust the values of a set of exposure parameters of the camera 4a, 4b, 4c, 4d. For example, the camera 4a, 4b, 4c, 4d may then be controlled by the data processing system 3 to capture a further camera image according to the adjusted values 8 (see for example Fig. 2) of the set of exposure parameters.

[0110] For example, the camera system 2 may be part of an electronic vehicle guidance system 2’ of the vehicle 1 . In this case, the electronic vehicle guidance system 2’, for example the data processing system 3, comprises a control system, which is configured to generate at least one control signal for guiding the vehicle 1 at least in part automatically depending on the further camera image and / or to generate driver assistance information for assisting a driver at guiding the vehicle 1 depending on the further camera image.

[0111] Fig. 2 shows a schematic flow diagram of an exemplary embodiment of a computer- implemented method for exposure control according to the invention, as it may be carried out by the data processing system 3 of Fig. 1 .

[0112] In step 200, a speed 6 of the vehicle 1 is received, in particular from a speed sensor 5, such as a wheel rotation speed sensor, of the vehicle 1 . An exposure profile is selected from at least two predefined exposure profiles depending on the speed 6 of the vehicle 1 , wherein each of the at least two predefined exposure profiles comprises a respective mapping rule for mapping an image property to respective values of a set of exposure parameters of the camera 4a, 4b, 4c, 4d. In step 240, the values of the set of exposure parameters of the camera 4a, 4b, 4c, 4d are adjusted according to the mapping rule of the selected exposure profile and depending on a predefined target value of the image property. The camera 4a, 4b, 4c, 4d may then be controlled according to the adjusted values 8 of the set of exposure parameters.

[0113] In optional step 220, a value of the image property is determined for a camera image 7 of the camera 4a, 4b, 4c, 4d. In this case, the values of the set of exposure parameters of the camera 4a, 4b, 4c, 4d are adjusted according to the mapping rule of the selected 2024PF01070

[0114] 16 exposure profile and depending on a deviation of the value of the image property of the camera image 7 from the target value of the image property in step 240.

[0115] Fig. 3 shows a schematic flow diagram of a part of a further exemplary embodiment of a computer-implemented method for exposure control according to the invention, which is based on the embodiment of Fig. 2. In particular, step 240 comprises steps 300 to 360 in this case.

[0116] In such embodiments, each of the at least two predefined exposure profiles comprises a plurality of bins for the value of the image property and the respective mapping rule assigns respective values of the set of exposure parameters to each of the plurality of bins. Each of the at least two predefined exposure profiles comprises at least one transition rule for a transition between bins of the respective plurality of bins. The values of the set of exposure parameters of the camera are adjusted according to the at least one transition rule of the selected exposure profile.

[0117] In particular, a current bin of the plurality of bins of the selected exposure profile is determined according to the value of the image property of the camera image 7 in step 300. Also in step 300, a target bin of the plurality of bins of the selected exposure profile is determined according to the target value of the image property.

[0118] In step 320, it is decided according to the at least one transition rule of the selected exposure profile, according to which bin of the plurality of bins the values of the set of exposure parameters shall be set. It is, in particular, decided whether the values of the set of exposure parameters shall be set to the values of the set of exposure parameters assigned to the target bin by the mapping rule of the selected exposure profile (option i)), to the values of the set of exposure parameters assigned to the current bin by the mapping rule of the selected exposure profile (option ii)), or to the values of the set of exposure parameters assigned to an intermediate bin between the current bin and the target bin by the mapping rule of the selected exposure profile (option iii)).

[0119] For example, option ii) may be chosen, if the deviation of the value of the image property of the camera image 7 from the target value of the image property is less than a predefined tolerance value. If this is not the case, option i) may be chosen, if a number of bins lying between the current bin and the target bin is equal to or less than a predefined maximum step width. Otherwise, option iii) may for example be chosen. 2024PF01070

[0120] 17

[0121] The set of exposure parameters comprises for example an exposure time. In this case, the exposure time is adjusted in step 340 according to the decision of step 320. The set of exposure parameters comprises for example an analog gain and / or a digital gain. In this case, the analog gain and / or the digital gain are adjusted in step 360 according to the decision of step 320.

[0122] Fig. 4 shows a schematic flow diagram of a part of a further exemplary embodiment of a computer-implemented method for exposure control according to the invention, which is based on the embodiment of Fig. 2. In particular, step 220 comprises steps 400 to 480 in this case.

[0123] In step 400, the camera image 7 is divided into a plurality of cells. In step 420, a cell intensity is determined for each cell of the plurality of cells depending on respective pixel values of the camera image 7 in the respective cell. For example, the cell intensity CI may wherein T denotes the exposure time, Gadenotes the analog gain, Gddenotes the digital gain, the sum runs over all pixels i of the respective cell, Vtdenotes the raw pixel value of the respective pixel, and Gc idenotes the color gain for the pixel i.

[0124] In step 440, the image intensity is determined as a weighted sum of the cell intensities for the plurality of cells.

Claims

2024PF0107018Claims1 . Computer-implemented method for exposure control of a camera (4a, 4b, 4c, 4d) of a vehicle (1 ), wherein a speed (6) of the vehicle (1) is received and an exposure profile is selected from at least two predefined exposure profiles depending on the speed (6) of the vehicle (1), each of the at least two predefined exposure profiles comprising a respective mapping rule for mapping an image property to respective values of a set of exposure parameters of the camera (4a, 4b, 4c, 4d) ; the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are adjusted according to the mapping rule of the selected exposure profile and depending on a predefined target value of the image property.

2. Computer-implemented method according to claim 1 , wherein a value of the image property is determined for a camera image (7) of the camera (4a, 4b, 4c, 4d); and the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are adjusted according to the mapping rule of the selected exposure profile and depending on a deviation of the value of the image property of the camera image (7) from the target value of the image property.

3. Computer-implemented method according to claim 2, wherein each of the at least two predefined exposure profiles comprises a plurality of bins for the value of the image property and the respective mapping rule assigns respective values of the set of exposure parameters to each of the plurality of bins; each of the at least two predefined exposure profiles comprises at least one transition rule for a transition between bins of the respective plurality of bins; and the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are adjusted according to the at least one transition rule of the selected exposure profile.

4. Computer-implemented method according to claim 3, wherein2024PF0107019 a current bin of the plurality of bins of the selected exposure profile is determined according to the value of the image property of the camera image (7); a target bin of the plurality of bins of the selected exposure profile is determined according to the target value of the image property; depending on the at least one transition rule of the selected exposure profile, the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are set to one of the following: i) the values of the set of exposure parameters assigned to the target bin by the mapping rule of the selected exposure profile; ii) the values of the set of exposure parameters assigned to the current bin by the mapping rule of the selected exposure profile; iii) the values of the set of exposure parameters assigned to an intermediate bin between the current bin and the target bin by the mapping rule of the selected exposure profile.

5. Computer-implemented method according to claim 4, wherein the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are set to the values of the set of exposure parameters assigned to the current bin by the mapping rule of the selected exposure profile, if the deviation of the value of the image property of the camera image (7) from the target value of the image property is less than a predefined tolerance value.

6. Computer-implemented method according to one of claims 4 or 5, wherein the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are set to the values of the set of exposure parameters assigned to the target bin by the mapping rule of the selected exposure profile only if a number of bins lying between the current bin and the target bin is equal to or less than a predefined maximum step width.

7. Computer-implemented method according to claim 6, wherein, if the number of bins lying between the current bin and the target bin is greater than a predefined maximum step width, the values of the set of exposure parameters of the camera (4a, 4b, 4c, 4d) are set to the values of the set of exposure parameters assigned to the intermediate bin by the mapping rule of the selected exposure profile.2024PF01070208. Computer-implemented method according to claim 7, wherein the number of bins lying between the current bin and the intermediate bin is equal to the maximum step width.

9. Computer-implemented method according to one of the preceding claims, wherein the set of exposure parameters comprises an exposure time and / or an analog gain and / or a digital gain and / or a color gain.

10. Computer-implemented method according to one of the preceding claims, wherein the image property is given by or depends on an image intensity.11 . Computer-implemented method according to claim 2 and claim 10, wherein the camera image (7) is divided into a plurality of cells; a cell intensity is determined for each cell of the plurality of cells depending on respective pixel values of the camera image (7) in the respective cell; and the image intensity is determined as a weighted sum of the cell intensities for the plurality of cells.

12. Computer-implemented method according to one of the preceding claims, wherein the camera (4a, 4b, 4c, 4d) is controlled to capture a further camera image according to the adjusted values (8) of the set of exposure parameters.

13. Method for guiding a vehicle (1 ) at least in part automatically, wherein a computer- implemented method according to claim 12 is carried out and at least one control signal for guiding the vehicle (1 ) at least in part automatically is generated depending on the further camera image; and / or driver assistance information for assisting a driver at guiding the vehicle (1 ) is generated depending on the further camera image.

14. Data processing system (3) adapted to carry out a computer-implemented method according to one of claims 1 to 12.

15. Camera system (2) for a vehicle (1 ) comprising a data processing system (3) according to claim 14 and the camera (4a, 4b, 4c, 4d).2024PF010702116. Electronic vehicle guidance system (2’) for a vehicle (1 ) comprising a data processing system (3) according to claim 14 or a camera system according to claim 15 and a control system, which is configured to generate at least one control signal for guiding the vehicle (1) at least in part automatically depending on the further camera image; and / or driver assistance information for assisting a driver at guiding the vehicle (1 ) depending on the further camera image.

17. Computer program product comprising - instructions, which, when executed by a data processing system (3), cause the data processing system (3) to carry out a computer-implemented method according to one of claims 1 to 12; and / or further instructions, which, when executed by an electronic vehicle guidance system (2’) according to claim 16, cause the electronic vehicle guidance system (2’) to carry out a method according to claim 13.

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