ON-BOARD CAMERA SYSTEM AND EXPOSURE CONDITIONS DETERMINATION PROCEDURES FOR ON-BOARD CAMERA

Abstract

An onboard camera system is provided, capable of capturing accurate three-dimensional and object recognition information without being affected by vehicle speed. This onboard camera system comprises a plurality of cameras arranged on the vehicle itself to provide a stereoscopic field of view in which at least part of a field of view overlaps; a motion magnitude calculation unit that determines the motion magnitude of a feature point within the stereoscopic field of view, as imaged by the plurality of cameras, based on the vehicle's behavior; and a first exposure condition determination unit that establishes a first exposure condition for the plurality of cameras such that the motion magnitude is less than or equal to a threshold value.a second exposure condition determination unit that determines a second exposure condition for the plurality of cameras based on an external light condition of the vehicle exterior; a three-dimensional information acquisition unit that acquires three-dimensional information of the stereoscopic field of view using an image mapped under the first exposure condition; an object detection unit that detects an object around the vehicle using an image mapped under the second exposure condition; and an exposure control unit that switches an exposure condition of each of the plurality of cameras to the first or the second exposure condition.

Description

Technical area

[0001] The present invention relates to an on-board camera system that recognizes an external environment of a self-vehicle using a plurality of cooperative cameras, and an exposure condition determination method for an on-board camera. State of the art

[0002] Vehicle control technologies such as adaptive cruise control (ACC), advanced emergency braking (AEBS), and lane keeping assist system (LKAS) are known as technical elements of a driver assistance system and an automatic driving system. A specific configuration for implementing these vehicle control technologies is one in which an object (e.g., other vehicles, pedestrians, cyclists, traffic lights, traffic signs, white lines, obstacles, and the like) around a host vehicle is continuously detected and tracked based on an image captured by an on-board camera, so that the host vehicle follows a preceding vehicle, an emergency brake is applied, and steering control is performed to avoid deviating from a lane.In addition, vehicles that enable automatic parking by arranging a multitude of cameras so that they are able to monitor not only the front and rear but also the sides of the vehicle are becoming widespread.

[0003] Here, PTL 1 is known as a conventional technique for controlling an exposure time of an on-board camera. In the abstract of this document, "an image around the vehicle is imaged and displayed taking into account a driving state of the vehicle" is described as a problem, and "an on-board camera control device including a vehicle speed detector that detects a vehicle speed of a vehicle on which an on-board camera is mounted, and a camera control device that changes an exposure time of the on-board camera according to the vehicle speed detected by the vehicle speed detector" is described as a solution. Furthermore, paragraph 0036 of this document describes "when the vehicle is moving at a high speed, an image around the vehicle can be displayed in real time, although the image is not clear." Citation listPatent literature

[0004] PTL 1: JP 2008-174078 A Summary of the inventionTechnical problem

[0005] As described above, the exposure time control of PTL 1 smoothly changes the exposure time of the on-board camera according to the vehicle speed to display the image around the own vehicle in real time. However, there is a problem that a clear image cannot be acquired at the time of high-speed movement through this exposure time control. Therefore, when using an unclear image imaged by the PTL 1 technique, an object around the own vehicle cannot be accurately detected, and there is a possibility that vehicle control such as ACC, AEBS, and LKAS cannot be adequately realized.

[0006] Therefore, an object of the present invention is to provide an on-board camera system and an exposure condition determination method for an on-board camera capable of acquiring accurate three-dimensional information and object detection information necessary for vehicle control such as ACC, AEBS, and LKAS without being affected by a vehicle speed by performing imaging while switching between exposure control for distance measurement and exposure control for object detection in a time-division manner. Solution to the problem

[0007] To solve the above problems, an on-board camera system includes a plurality of cameras arranged on a self-vehicle so as to have a stereoscopic view area in which at least a part of a field of view overlaps; a movement amount calculation unit that obtains a movement amount of a feature point of the stereoscopic view area imaged by the plurality of cameras based on a behavior of the self-vehicle; a first exposure condition determination unit that determines a first exposure condition of the plurality of cameras so that the movement amount becomes less than or equal to a threshold value; a second exposure condition determination unit that determines a second exposure condition of the plurality of cameras based on an external light condition of a vehicle exterior;a three-dimensional information acquisition unit that acquires three-dimensional information of the stereoscopic view using an image captured under the first exposure condition; an object detection unit that detects an object around the host vehicle using an image captured under the second exposure condition; and an exposure control unit that switches an exposure condition of each of the plurality of cameras to the first exposure condition or the second exposure condition. Advantageous effects of the invention

[0008] According to the on-board camera system and the exposure condition determination method for the on-board camera of the present invention, three-dimensional information and object detection information necessary for vehicle control such as ACC, AEBS, and LKAS are obtained without being affected by a vehicle speed by performing imaging while switching between the exposure control for distance measurement and the exposure control for object detection in a time-division manner. Short description of the drawings Fig. 1 shows a functional block diagram of an on-board camera system according to an example. Fig. 2 is a plan view illustrating a relationship between a field of view area and a stereo view area of ​​each camera. Fig. 3 shows a functional block diagram of a camera control unit in Fig. 1. Fig. 4 shows a processing flow diagram of an on-board camera system according to an example. Fig. 5 shows a specific example of a calculation line of three-dimensional information and a calculation range of a feature point movement amount. Description of embodiments

[0009] Hereinafter, an on-board camera system 100 according to an example of the present invention will be described with reference to the drawings.

[0010] Fig. 1 shows a functional block diagram of an on-board camera system 100. The on-board camera system 100 is a system mounted on a self-vehicle 1 and includes an arithmetic processing device 10, a camera 20 (21 to 26), a vehicle control device 30, and a light projector 40. The arithmetic processing device 10 will be described in detail below after outlining the camera 20, the vehicle control device 30, and the light projector 40. <Kamera 20>

[0011] The camera 20 is a sensor that images the periphery of the own vehicle and outputs imaged data P. A plurality of cameras 20 (21 to 26) are installed in the own vehicle 1 of the present example to be able to image the entire periphery of the exterior of the vehicle. Note that it is assumed that each camera is installed so that at least part of an imaging range overlaps with an imaging range of another camera.

[0012] Fig. Fig. 2 shows a plan view of the own vehicle 1 and is a diagram illustrating a relationship between a field of view C of each camera and a stereo view range V. In the own vehicle 1 of the present example, a front camera 21 having a front field of view C 21indicated by a solid line, a front right camera 22, which has a front right field of view area C 22 indicated by a one-point chain line, a rear right camera 23 which has a rear right field of view area C 23 indicated by a dashed line, a rear camera 24 having a rear field of view C 24 indicated by a solid line, a rear left camera 25, which has a rear left field of view area C 25 indicated by a one-point chain line, and a front left camera 26 which forms a front left field of view area C 26 indicated by a dashed line, and the entire periphery of the vehicle exterior can be imaged by these six cameras 20.

[0013] In an area where a plurality of visual field areas C overlap, the same object can be imaged from a plurality of line-of-sight directions (stereo imaging), and three-dimensional information of an imaged object (moving body, stationary object, road surface, etc. around the own vehicle) can be generated using a known stereo matching technique. Therefore, an area where the visual field areas C overlap is referred to as a stereo visual area V.

[0014] It should be noted that in Fig. 2 illustrates the front, rear, left, and right stereoscopic view areas V1 to V4, but the number and direction of the stereoscopic view areas V are not limited to this example. In addition, Fig. 2 illustrates the field of view C of each camera in a simplified manner, and the actual imageable distance of each camera may not have the illustrated size relationship. As an example, the actual imageable distance of each camera is approximately 200 m for the front camera 21 and the rear camera 24, and approximately 50 m for the other cameras. In this case, the imageable distance of the stereo field of view V is approximately 50 m. <Fahrzeugsteuervorrichtung 30>

[0015] The vehicle control device 30 is a control device that controls a steering system, a drive system, and a braking system (not illustrated) based on a result of object distance measurement described later, and the like, to perform vehicle control such as ACC, AEBS, LKAS, automatic parking, and the like. Note that the vehicle control device 30 also transmits vehicle speed information of the host vehicle 1 to the camera control unit 12 described later, and requests priority transmission of desired information (three-dimensional map, host vehicle attitude, object detection, object distance measurement). <Lichtprojektor 40>

[0016] The light projector 40 is a device that projects visible light or near-infrared light with a desired amount of light within the range of the stereoscopic view V, allowing each camera to image clearer image data P. When the outside of the vehicle 1 is sufficiently bright, the light projector 40 may not be used. Furthermore, when the light projector 40 is used, constant light projection is not necessary, and light can be projected synchronously with the imaging timing of each camera. <Arithmetische Verarbeitungsvorrichtung 10>

[0017] The arithmetic processing device 10 is a device for acquiring three-dimensional information around the own vehicle, determining a own vehicle attitude, detecting an object (e.g., other vehicles, pedestrians, cyclists, traffic lights, traffic signs, white lines, obstacles, etc.) around the own vehicle, and measuring a distance to the object based on an output (image data P) of the camera 20. Note that the arithmetic processing device 10 is specifically a computer that includes an arithmetic device such as a CPU, a storage device such as a semiconductor memory, and hardware such as a communication device.Then, the arithmetic device executes a predetermined program to realize each functional unit such as the camera control unit 12 to be described later, and a description will be given below while omitting such a well-known technique as appropriate.

[0018] As in Fig. As illustrated in Fig. 1, the arithmetic processing device 10 of the present example includes a sensor interface 11, a camera control unit 12, a light projector control unit 13, an image distribution unit 14, a feature point movement amount calculation unit 15, a three-dimensional information acquisition unit 16, a three-dimensional map storage unit 17, a self-vehicle attitude determination unit 18, an object recognition unit 19, and an object distance measurement unit 1a. Functions of the respective units will be described sequentially below. Sensor interface 11

[0019] The sensor interface 11 is a functional unit that transmits a command from the camera control unit 12 to the camera 20 (21 to 26), receives the image data P from the camera 20 (21 to 26), and transmits the image data P to the image distribution unit 14. As a result, each camera can image the image data P under the exposure conditions set by the camera control unit 12. Note that details of the exposure conditions will be described later. Camera control unit 12

[0020] The camera control unit 12 is a functional unit that controls the camera 20 (21 to 26) via the sensor interface 11 and controls the light projector 40 via the light projector control unit 13. As shown in Fig. As illustrated in FIG. 3, the camera control unit 12 includes a reference exposure condition storage unit 12a, a first exposure condition determination unit 12b, an external light condition determination unit 12c, a second exposure condition determination unit 12d, an exposure control unit 12e, an imaging control unit 12f, and a light projection condition determination unit 12g. Each unit will be described in detail below.

[0021] The reference exposure condition storage unit 12a is a functional unit that stores a reference exposure condition (reference exposure time) to be set for each camera when the arithmetic processing device 10 is activated or when the vehicle speed or the vehicle external environment is greatly changed.

[0022] The first exposure condition determination unit 12b is a functional unit that determines the first exposure condition based on the feature point movement amount received from the feature point movement amount calculation unit 15 described later or the vehicle speed information received from the vehicle control device 30. The first exposure condition defines an exposure time when image data P1 for acquiring three-dimensional information is imaged, and an exposure time in which a feature point movement amount becomes less than or equal to a predetermined threshold (e.g., two pixels) or an exposure time inversely proportional to a vehicle speed is set.

[0023] The external lighting condition determination unit 12c is a functional unit that determines an external lighting condition of the vehicle exterior based on luminance information of the image data P received from the image distribution unit 14 described later. Note that, when determining the external lighting condition, for example, the gain set for each camera and the average luminance in the image data P are taken into account. Therefore, even if the average luminance of the image data P is the same, it is determined that the outside world is dark when the gain is high, and it is determined that the outside world is bright when the gain is low.

[0024] The second exposure condition determining unit 12d is a functional unit that determines the second exposure condition based on the external light condition determined by the external light condition determining unit 12c. The second exposure condition defines an exposure time when the image data P2 for detecting the object is imaged, and an exposure time that is substantially inversely proportional to the amount of external light is set. The relationship between the amount of external light and the second exposure condition can be obtained from a predetermined arithmetic expression, or a pre-prepared table can be referenced.

[0025] It should be noted that when comparing the exposure time under the first exposure condition with the exposure time under the second exposure condition, the first is essentially short and the second is long. Therefore, the image data P1 imaged under the first exposure condition has a disadvantage in that the image is dark and thus not suitable for detecting an object, but has an advantage in that an environmental change around the own vehicle can be quickly detected because the sampling period is short. On the other hand, the image data P2 imaged under the second exposure condition has a disadvantage in that it is not suitable for quickly detecting the environmental change around the own vehicle because the sampling period is long, but has an advantage in that the image is bright and thus an object can be accurately detected.

[0026] The exposure control unit 12e is a functional unit that selects one of the reference exposure condition, the first exposure condition, and the second exposure condition according to the processing procedure, the vehicle speed, the detected object type, distance, collision possibility, and the like, and transmits the selected one to the imaging control unit 12f. Note that in the present example, since the exposure conditions of each camera are set in a time-division multiplex manner while considering the priority application of each camera at that time, the image data P1 for three-dimensional information acquisition and the image data P2 for object recognition are output from each camera in a predetermined ratio. For example, if the priority application of the camera 20 is three-dimensional information acquisition, such as a three-dimensional image,When the host vehicle 1 is traveling at a high speed or when an object with a possibility of collision is detected, it is only necessary to image a large number of image data items P1 and a small number of image data items P2 by increasing the usage ratio of the first exposure condition, and when the priority application of the camera is object detection, it is only necessary to image a small number of image data items P1 and a large number of image data items P2 by increasing the usage ratio of the second exposure condition.

[0027] Further, when the exposure condition is set taking the vehicle speed into account, the exposure condition is set as follows. For example, when the host vehicle 1 is moving at a constant speed (e.g., 10 km / h) or more, the first exposure condition for acquiring three-dimensional information is preferably set for each camera. Specifically, the ratio (period or number of times) of setting the first exposure condition is increased for each camera, and the ratio (period or number of times) of setting the second exposure condition is suppressed. On the other hand, when the host vehicle 1 is moving at a speed lower than the constant speed, the second exposure condition for object detection is preferably set for each camera.

[0028] Here, the same exposure condition needs to be set for the camera group corresponding to the same stereoscopic view V, but different exposure conditions can be set at the time of synchronization as long as the stereoscopic view V between the cameras is different. For example, when the host vehicle 1 is moving forward, the first exposure condition for acquiring three-dimensional information may be preferentially set to the camera group (front camera 21, front right camera 22, front left camera 26) corresponding to the front stereoscopic view V1, and the second exposure condition for object detection may be preferentially set to the camera group (rear right camera 23, rear camera 24, rear left camera 25) corresponding to the rear stereoscopic view V3.

[0029] The imaging control unit 12f is a functional unit that controls the imaging timing of each camera using the exposure condition set by the exposure control unit 12e. Here, a camera group corresponding to the same stereoscopic view V needs to be imaged synchronously, but the imaging timings may be different between cameras with different stereoscopic view Vs. Therefore, for example, in a case where the same imaging period (e.g., 50 ms) is set for the camera group (21, 22, 26) corresponding to the front stereoscopic view V1 and the camera group (23, 24, 25) corresponding to the rear stereoscopic view V3, a time difference (e.g., 25 ms), which is, for example, half a period, can be provided for the former and latter imaging timings. As a result, it is possible to substantially halve the sampling period for imaging the vehicle exterior.

[0030] The light projection condition determination unit 12g is a functional unit that determines the light projection timing and light projection amount of the light projector 40 based on the output of the imaging control unit 12f and transmits the light projection timing and light projection amount to the light projector control unit 13. As described above, since it is sufficient for the light projector 40 to project light during imaging by each camera, power consumption in the light projector 40 can be suppressed by controlling no light to be projected during a period when each camera is not performing imaging. <Lichtprojektorsteuereinheit 13>

[0031] The light projector control unit 13 is a functional unit that controls the light projection of the light projector 40 according to the light projection timing and the light projection amount determined by the light projection condition determination unit 12g. <Bildverteilungseinheit 14>

[0032] The image distribution unit 14 is a functional unit that distributes the image data P received via the sensor interface 11 to the camera control unit 12, the feature point movement amount calculation unit 15, the three-dimensional information acquisition unit 16, or the object recognition unit 19 according to a control procedure, a driving situation of the host vehicle 1, a request content of the vehicle control device 30, or the like. Note that it is assumed that information indicating an exposure condition (or exposure time) is added to the image data P so that the type of the image data P can be distinguished by the image distribution unit 14. <Merkmalspunktbewegungsbetragsberechnungseinheit 15>

[0033] The feature point movement amount calculation unit 15 is a functional unit that calculates a movement amount in the image data P for any feature point in the image data P received from the image distribution unit 14.

[0034] Fig. 4(a) is an example of a movement of a feature point in the image data P. As illustrated in the drawing, in a case where the end portion of the far side of the white line drawn on the road surface is set as the feature point, when the host vehicle 1 is stopped, the boundary between the end portion of the far side of the white line and the road surface on the far side is clear, and thus, it can be determined that the movement amount of the feature point is small, but in the image data P of Fig. 4, imaged by the host vehicle 1 traveling at high speed, the boundary between the end portion of the far side of the white line and the road surface becomes ambiguous, and thus, it can be determined that the movement amount of the feature point is large. Therefore, the feature point movement amount calculation unit 15 calculates the movement amount of the feature point based on the clarity of the image near the feature point. Note that since the movement amount of the feature point is proportional to the vehicle speed, the calculation of the movement amount of the feature point can also be considered as an approximation of the vehicle speed. Three-dimensional information acquisition unit 16

[0035] The three-dimensional information acquisition unit 16 is a functional unit that acquires three-dimensional information for each pixel on an arbitrary calculation line on a set of image data P obtained by synchronously imaging the stereo visual area V using a known stereo matching technique.

[0036] Fig. 4(b) is a calculation line for capturing three-dimensional information exemplified in the image data P. In the image data P shown in Fig. 4, the sky is substantially imaged in the upper half, and the road surface is substantially imaged in the lower half, so that when a calculation line is set in the vertical direction of the image data P and stereo matching is performed on the calculation line, the nearest distance information for the pixel on the road surface at the lower end of the image data P is calculated, the gradually increasing distance information for the pixel on the road surface from the lower end to substantially the center of the image data P is calculated, and the distance information indicating invalidity (an unmeasurable distance) is calculated for the blank pixel from substantially the center to the upper end. It should be noted that although only one calculation line is set in Fig. 4, when there is a margin in the calculation capability, a plurality of calculation lines having an arbitrary angle to which image data P can be set, and three-dimensional information can be calculated for each of the calculation lines. Three-dimensional map storage unit 17

[0037] The three-dimensional map storage unit 17 is a functional unit that accumulates the three-dimensional information acquired by the three-dimensional information acquisition unit 16 in time series to generate and store a three-dimensional map indicating a road surface gradient, an object, and the like around the own vehicle. Note that in a case where the past three-dimensional information of the object considered to be a moving object is stored in the three-dimensional map storage unit 17, it is desirable that the first exposure condition be preferably set for each camera, and the current three-dimensional information of the moving object can be updated so that the moving object can be tracked. Own vehicle position determination unit 18

[0038] The own vehicle attitude determination unit 18 is a functional unit that determines the attitude of the own vehicle 1 with respect to the road surface based on the three-dimensional map stored in the three-dimensional map storage unit 17. Object recognition unit 19

[0039] The object recognition unit 19 is a functional unit that recognizes an object depicted in image data P2 using a known pattern matching technique.

[0040] Fig. 4(c) illustrates an object detected by the object detection unit 19 from the image data P. In this example, a preceding vehicle traveling in the lane of the own vehicle and a preceding vehicle traveling in the right lane of the own vehicle are detected. In this case, the former is recognized as an object (another vehicle) by pattern matching with an image pattern obtained by imaging the vehicle from the rear, and the latter is recognized as an object (another vehicle) by pattern matching with an image pattern obtained by imaging the vehicle from the left rear. Object distance measuring unit 1a

[0041] The object distance measuring unit 1a is a functional unit that determines the distance to the object based on the entire width, the entire height, and the like of the object detected by the object detection unit 19 in the image data P. Note that when the object is located within the stereoscopic view range V, the distance to the object may be calculated using a stereo matching technique, or when the distance to the object is registered in advance as a three-dimensional map, the distance indicated by the three-dimensional map may be adopted as the distance to the object. Since the information on the distance to the object obtained here is transmitted to the vehicle control device 30, the vehicle control device 30 can execute various vehicle controls such as ACC, AEBS, and automatic parking according to the distance to the object. <ablaufdiagramm>

[0042] Next, processes of each unit of the above-described on-board camera system 100 will be described with reference to a flowchart of Fig. 5 will be described in sequence. To simplify the description, it is assumed that the brightness of the vehicle exterior is constant and the vehicle speed is also constant.

[0043] First, in step S1, the camera control unit 12 (12a, 12e, 12f) sets a reference exposure condition for each camera and causes each camera 20 to image image data P.

[0044] In step S2, the feature point movement amount calculation unit 15 calculates the feature point movement amount based on the image data P imaged in step S1.

[0045] In step S3, the camera control unit 12 (12b) determines whether the calculated feature point movement amount is less than or equal to a predetermined threshold. Then, if the feature point movement amount is less than or equal to the predetermined threshold, the process proceeds to step S5, and if not, the process proceeds to step S4.

[0046] In step S4, the camera control unit 12 (12b, 12e, 12f) sets a shorter exposure time for the camera 20 and causes the camera to image the image data P. Since the processes of steps S2 and S3 described above are also executed for the newly imaged image data P, the exposure time at which the feature point movement amount becomes less than or equal to the predetermined threshold is finally determined.

[0047] In step S5, the camera control unit 12 (12b) determines, as the first exposure condition, the exposure time at which the feature point movement amount becomes less than or equal to the predetermined threshold.

[0048] In step S6, the camera control unit 12 (12c) detects an external lighting condition of the vehicle exterior based on the image data P.

[0049] In step S7, the camera control unit 12 (12d) determines the second exposure condition based on the external light condition.

[0050] In step S8, the camera control unit 12 (12e) sets the purpose of the next imaging, taking into account the exposure conditions and the like that are preferably set for each camera. If the next imaging purpose is to acquire distance information (three-dimensional information, subject vehicle attitude information), the process proceeds to step S9, and if the next imaging purpose is to acquire object information (object detection information, object distance measurement information), the process proceeds to step S12.

[0051] In step S9, the camera control unit 12 (12b, 12e, 12f, 12g) sets the first exposure condition for the camera 20 and causes the camera 20 to image the image data P1.

[0052] In step S10, the three-dimensional information acquisition unit 16 acquires three-dimensional information based on a plurality of pieces of image data P1 obtained by synchronously imaging the same stereoscopic view area V. Furthermore, the acquired three-dimensional information is stored in the three-dimensional map storage unit 17 as a three-dimensional map.

[0053] In step S11, the own vehicle attitude determination unit 18 determines the attitude of the own vehicle 1. The determined own vehicle attitude is transmitted to the vehicle control device 30 and used for vehicle control.

[0054] On the other hand, in step S12, the camera control unit 12 (12d, 12e, 12f, 12g) sets the second exposure condition for the camera 20 and causes the camera to image the image data P2.

[0055] In step S13, the object recognition unit 19 recognizes the object in the image data P2.

[0056] In step S14, the object distance measuring unit 1a measures the distance to the detected object. The measured distance to the object is transmitted to the vehicle control device 30 and used for the desired vehicle control.

[0057] In step S15, the arithmetic processing device 10 determines whether the trip is completed. If the trip is not completed, the process returns to step S8 and imaging continues. As a result, each camera can image the image data P1 and P2 in a predetermined ratio. On the other hand, if the trip is completed, the process is Fig. 5. If the brightness of the vehicle exterior or the vehicle speed changes significantly, the processes of step S1 may be executed again.

[0058] According to the on-board camera system of the present example described above, by switching the exposure control for distance measurement and the exposure control for object detection to a time-division manner and performing imaging, accurate three-dimensional information and object detection information necessary for vehicle control such as ACC, AEBS, and LKAS can be acquired without being affected by the vehicle speed. List of reference symbols 1 own vehicle 100 on-board camera system 10 arithmetic processing device 11 Sensor interface 12 Camera control unit 12a Storage unit for reference exposure conditions 12b first exposure condition determination unit 12c external light condition determination unit 12d second exposure condition determination unit 12e exposure control unit 12f Imaging control unit 12g light projection condition determination unit 13 Light projector control unit 14 Image distribution unit 15 Feature point movement amount calculation unit 16 three-dimensional information acquisition unit 17 three-dimensional map storage unit 18 Own vehicle position determination unit 19 Object recognition unit 1a Object distance measuring unit 20 (21 to 26) Camera 30 Vehicle control device 40 light projector C Field of view V Stereo field of view P Input data QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] JP 2008-174078 A

[0004] < / ablaufdiagramm>

Claims

[1] On-board camera system comprising: a plurality of cameras arranged on a vehicle of the user to have a stereoscopic field of view in which at least a portion of a field of view overlaps; a movement amount calculation unit that obtains a movement amount of a feature point of the stereo view area imaged by the plurality of cameras based on a behavior of the own vehicle; a first exposure condition determining unit that determines a first exposure condition of the plurality of cameras so that the amount of movement becomes less than or equal to a threshold value; a second exposure condition determining unit that determines a second exposure condition of the plurality of cameras based on an external light condition of a vehicle exterior; a three-dimensional information acquisition unit that acquires three-dimensional information of the stereo visual area using an image imaged under the first exposure condition; an object detection unit that detects an object around the own vehicle using an image captured under the second exposure condition; and an exposure control unit that switches an exposure condition of each of the plurality of cameras to the first exposure condition or the second exposure condition. [2] The on-board camera system according to claim 1, wherein the exposure control unit prioritizes the first exposure condition over the second exposure condition in a case where a vehicle speed of a subject vehicle is greater than or equal to a predetermined value. [3] The on-board camera system of claim 1, further comprising a storage unit that stores the three-dimensional information of the stereo vision area acquired in the past by the three-dimensional information acquisition unit in association with an object included in the stereo vision area; wherein the exposure control unit prioritizes the first exposure condition over the second exposure condition in a case where the three-dimensional information of the object included in the stereo view area at a current point is stored in the storage unit. [4] An on-board camera system according to claim 1, wherein the plurality of cameras are arranged to have a plurality of stereo viewing areas, and the exposure control unit switches the first exposure condition and the second exposure condition for each camera group that images each stereo field of view. [5] The on-board camera system according to claim 4, wherein, in a case where an object having a possibility of collision with the own vehicle is present in one of the plurality of stereoscopic view areas, the exposure control unit prioritizes the first exposure condition over the second exposure condition for a camera imaging a stereoscopic view area in which the object is detected. [6] The on-board camera system of claim 4, further comprising an imaging timing control unit that controls an imaging timing so that an imaging timing of a camera that images a first stereoscopic view area and an imaging timing of a camera that images a second stereoscopic view area are shifted by a predetermined time among the plurality of cameras, wherein the three-dimensional information acquisition unit acquires the three-dimensional information based on an image imaged in the first stereoscopic view area and an image imaged in the second stereoscopic view area. [7] The on-board camera system according to claim 1, further comprising a light projector that projects light synchronously with the imaging of the camera. [8] An exposure condition determination method for an on-board camera, comprising: an imaging step of imaging a stereo view area in which a field of view area of ​​a plurality of cameras overlaps; a movement amount calculation step of obtaining a movement amount of a feature point of the stereo view area imaged by the plurality of cameras based on a behavior of a self-vehicle; a first exposure condition determining step of determining a first exposure condition of the plurality of cameras so that the movement amount becomes less than or equal to a threshold value; a second exposure condition determining step of determining a second exposure condition of the plurality of cameras based on an external light condition of a vehicle exterior; a three-dimensional information acquiring step of acquiring three-dimensional information of the stereo visual range using an image imaged under the first exposure condition; an object detection step of detecting an object around the own vehicle using an image captured under the second exposure condition; and an exposure control step of switching an exposure condition of each of the plurality of cameras to the first exposure condition or the second exposure condition.

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