Stereo camera arrangement for a motor vehicle and motor vehicle with such a stereo camera arrangement

Abstract

Stereo camera arrangement (1) for a motor vehicle (2) with at least a first and a second camera device (3, 4), characterized by at least two mutually separate holding devices, via which the at least first and second camera devices (3, 4) can be attached independently of one another to an inner side of a vehicle window (5) of the motor vehicle (2), wherein the first camera device (3) is designed as a satellite camera and the second camera device (4) is designed as an intelligent camera, wherein the intelligent camera comprises an image evaluation unit which is designed to evaluate a distance to an object by means of the images recorded by the camera devices.

Description

[0001] The invention relates to a stereo camera arrangement for a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle with such a stereo camera arrangement.

[0002] Driver assistance systems in motor vehicles often use a camera system to detect objects in the vehicle's surroundings, for example, in the area ahead in the direction of travel. Such camera systems are located, for example, in the vehicle interior behind the windshield and view through the windshield in the direction of travel.

[0003] Some driver assistance systems, such as accident avoidance systems (e.g., emergency braking systems), or systems with longitudinal or lateral guidance support (e.g., cruise control systems or lane departure warning systems), require the most accurate information possible about the vehicle's surroundings. Detecting objects and determining their distance to them plays an important role. Beam sensors, such as ultrasonic, radar, or lidar systems, are currently primarily used to determine object distance.

[0004] However, object distances can also be determined using stereo camera devices using the stereo effect. Stereo camera devices consist of two usually identical camera modules or mono cameras, which are constructed as separate optical systems, i.e., each with an image recording element and an imaging system (e.g., a lens). The two camera modules are usually aligned with their optical axes parallel to each other and arranged laterally offset next to each other behind the windshield, i.e., offset next to each other on a line parallel to the vehicle's transverse axis.

[0005] To exploit the stereo effect, it is essential to have precise knowledge of the base width, in other words the eye distance of the vehicle cameras of the stereo camera device.

[0006] Today's stereo camera devices are currently mounted on a common support for stability, production, and calibration reasons. For example, a stereo camera device with a common support is known from WO 2014 / 015 867 A1. To accommodate a deviation in the base width and thus determine the object distance as reliably as possible, the support device must be designed to be highly stable and made of a material with a low coefficient of thermal expansion, as vehicle cameras are subject to significant temperature fluctuations. However, this requires a considerable amount of space, creating a conflicting objective between achieving a compact design and unobtrusive installation in the vehicle interior.

[0007] DE 102009031650 A1 describes a method for expanding a camera system for a vehicle, wherein the camera system, prior to the expansion, comprises a first camera and an evaluation unit. The evaluation unit is designed to support a driver assistance system of the vehicle. The first camera is coupled to the evaluation unit via a first communication connection. The first camera and the evaluation unit are arranged in a common housing. The camera system is expanded by a second camera to form a stereo camera system, which enables a three-dimensional representation of the environment.

[0008] DE 102014017128 A1 describes a motor vehicle with a driver assistance system comprising a control device and a camera recording the area in front of the vehicle, the images of which can be processed by the control device to capture information on which the operation of the driver assistance system is based, wherein a portable image recording device which can be fixed by means of a holder in the area of ​​the windshield can be controlled via a communication connection by the control device to record images of the area in front of the vehicle, which images can be processed together with images from the camera to obtain three-dimensional stereoscopic information.

[0009] The invention is based on the object of providing an improved stereo camera arrangement.

[0010] This object is achieved by a stereo camera arrangement having the features of claim 1 and by a motor vehicle having the features of claim 8. Advantageous or preferred embodiments of the invention are set forth in the subclaims, the following description, and the figures.

[0011] A stereo camera arrangement for a motor vehicle is proposed. For example, the stereo camera arrangement is designed for environmental detection, in particular for detecting the surrounding area in front of or behind the vehicle.

[0012] For environmental detection, the stereo camera arrangement comprises at least a first and a second camera device. Preferably, the first and second camera devices each have an optical system for projecting light and at least one or more image sensors for detecting the light projected by the optical system. Preferably, the first and second cameras are mounted in the vehicle interior behind a windshield or rear window, thus facing in or against the direction of travel.

[0013] According to the invention, the stereo camera arrangement comprises at least or exactly two separate mounting devices, via which the at least first and second camera devices can be or are mounted independently of one another on the inside of a vehicle window, in particular a windshield of the vehicle's own motor vehicle. Thus, the at least first and second camera devices can be freely positioned, in other words, can be or are mounted on the inside of the vehicle window without coupling to one another. Thus, in particular, the vehicle window forms the common support device for the at least first and second camera devices.

[0014] This eliminates the need for an additional support device. A key advantage is the elimination of the thermal expansion coefficient in the lateral direction between the at least two camera units caused by the support device previously required. Temperature-related fluctuations in the base width and the associated inaccurate distance determinations can thus be prevented or at least significantly reduced.

[0015] In particular, the vehicle windscreen, which is essentially made of glass, has a thermal expansion coefficient that is almost an order of magnitude lower than the support devices typically made of metal. Consequently, using the vehicle windscreen as the common support device can at least achieve a near-redundancy with active sensor systems such as radar.

[0016] Furthermore, the elimination of the support device allows for a compact design of the stereo camera device. Since there is no rigid coupling between the two stereo camera devices, it is advantageously possible to mount the at least first and second camera devices almost anywhere on the inside of the vehicle window. This allows for an unobtrusive arrangement of the camera devices.

[0017] Furthermore, the base width was previously limited due to the support structure. The independent positioning of the camera units relative to each other increases the lateral distance between at least two camera units relative to the line of sight, allowing for greater accuracy in distance determination.

[0018] For example, the holding devices are designed as holding elements in which the camera devices are accommodated. Preferably, the holding devices are directly connectable or connected to the inside of the vehicle window.

[0019] In a preferred embodiment, the first and second camera devices are mounted or can be mounted offset from one another, in particular vertically offset from one another, on the inside of the vehicle window. Thus, the camera devices are preferably mounted or can be mounted or can be mounted offset from one another along a vertical axis of the vehicle's own motor vehicle. Alternatively or optionally, the first and second camera devices are arranged at a lateral distance from one another, in particular along a transverse axis of the vehicle's own motor vehicle.

[0020] For example, the camera devices can be or are mounted in different areas of the vehicle window. Preferably, the camera devices can be mounted in one of the four corner areas, in an upper end area, in a lower end area, or in one of the lateral end areas of the vehicle window.

[0021] Preferably, the camera devices for recording the wiping process are mountable or mounted in the wiping area of ​​the windscreen wipers.

[0022] According to a preferred embodiment, the first camera device is designed as a satellite camera and the second camera device as an intelligent camera. In particular, the intelligent camera, in particular the image recording sensor of the intelligent camera, comprises an image evaluation unit which is designed to evaluate the distance to an object using the images recorded by at least the first and second camera devices. The objects to be evaluated and the distance to be evaluated therefor are, for example, other road users, traffic signs, intersection areas and / or traffic lights. A satellite camera is to be understood in particular as a camera without an image evaluation unit. In particular, the satellite camera is coupled to the intelligent camera for transmitting the recorded images to the image evaluation unit.

[0023] According to an alternative preferred embodiment, the first and second camera devices are each embodied as satellite cameras. In particular, the stereo camera arrangement comprises, or is connectable to, an image evaluation unit configured to evaluate a distance to an object using the images captured by the camera device. In particular, the satellite cameras are coupled to the image evaluation unit for transmitting the captured images. For example, the image evaluation unit is a central ECU (electronic control unit) of the vehicle's own vehicle.

[0024] According to a further preferred embodiment, the stereo arrangement comprises at least one third camera device. The free positioning of the camera devices makes it possible, in particular, to install the at least one third and optionally additional camera devices discreetly.

[0025] Furthermore, the image evaluation unit of at least one of the camera devices or the image evaluation unit of the motor vehicle is preferably designed to evaluate a distance to an object located in a first distance range using the images recorded by the first and second camera devices and a distance to an object located in a second distance range using the images recorded by the second and third camera devices. In particular, the distance ranges differ. For example, the first distance range from the vehicle's own motor vehicle is to be understood as a close range, for example a distance range between one and 50 meters, and / or the second distance range from the vehicle's own motor vehicle is to be understood as a long-distance range, for example a distance range between 50 and 500 meters.

[0026] The first and second camera devices are preferably designed to each capture an image with equally large capture areas, so that a large-area coverage of the surrounding area is possible.

[0027] The second and third camera devices are preferably designed to each capture an image with detection areas of different sizes. Furthermore, it is preferred that the detection area of ​​the first and second camera devices be at least twice, and in particular at least four times, larger horizontally and / or vertically than the detection area of ​​the third camera device. This avoids, in particular, unnecessary computational effort for a detection area that must be evaluated twice.

[0028] In terms of structural design, it is preferred that the first and / or second camera device be designed as a wide-angle camera comprising a wide-angle lens with a horizontal and / or vertical angle of view of, for example, at least + / - 30 degrees, in particular of at least + / - 50 degrees, relative to the optical axis. The third camera device comprises, for example, a lens with a horizontal and / or vertical angle of view of, for example, at most + / - 15 degrees relative to the optical axis.

[0029] Furthermore, it is preferred that a central image section of the images to be recorded or recorded by the second camera device and the images to be recorded or recorded by the third camera device have at least twice, in particular four times, the resolution of the images to be recorded or recorded by the first camera device. In this way, object recognition in the long-range range is possible by means of the second and third camera device. The central image section has, for example, a horizontal, or alternatively or optionally additionally a vertical, image angle of + / - 15 degrees to the optical axis. A peripheral image section adjoining the central image section has, for example, a horizontal, or alternatively or optionally additionally a vertical, image angle of at least + / - 50 degrees to the optical axis.

[0030] Furthermore, it is preferred that the images to be recorded or recorded by the second camera device each have a higher resolution, in particular at least twice the resolution, in a central image section than in the peripheral image section. For example, the resolution decreases at least in some sections with increasing horizontal and / or vertical angles of view. In this way, on the one hand, the computational effort for object evaluation in the near field is limited to the bare minimum, while on the other hand, reliable object evaluation in the far field is ensured.

[0031] In terms of design, it is preferred that the second and / or third camera device each have a high-resolution image recording sensor with a resolution of at least five megapixels, at least in some sections. As an exemplary alternative, the second camera device may comprise a nonlinear optics system, in particular an anamorphic optics system.

[0032] Accordingly, the conflict of objectives of enabling the evaluation of objects in the largest possible detection range on the one hand, and in the long-distance range on the other, with a feasible image processing effort, has been resolved.

[0033] For example, the stereo camera arrangement comprises at least one further holding device, via which the third camera device can be attached to the inside of the vehicle window of the motor vehicle, independently of the first and second camera devices. As an exemplary alternative, the third camera device is an external camera of a camera surround-view system. For example, the external camera of a camera surround-view system is arranged on a roof node or on a bumper of the vehicle's own vehicle. By combining the camera devices to be attached in the interior and the external camera, it is advantageously possible to dispense with the need for an additional camera device to be attached in the interior. At the same time, by combining different optics, image recording sensors and / or base stations, depth measurements in the near and far range can advantageously be achieved simultaneously.A space-saving arrangement is achieved, especially compared to the one-box design. Precise knowledge of the relative positions of the camera devices is essential for distance determination, which can be precisely determined, for example, by using stop edges for the camera device arrangement.

[0034] Preferably, the stereo camera arrangement can be connected to or integrated into a driver assistance device of the vehicle's own motor vehicle, wherein the driver assistance device is particularly designed to initiate appropriate measures based on the distance to an object evaluated by means of the image evaluation unit, such as issuing a warning to the driver and / or actively intervening in the vehicle dynamics.

[0035] Another object of the invention relates to a motor vehicle with a stereo camera arrangement according to the preceding description. The at least first and second camera devices are mounted independently of one another on the inside of a vehicle window of the motor vehicle via the at least two separate mounting devices. The motor vehicle preferably comprises the image evaluation unit, which is designed to evaluate a distance to an object using the images captured by the camera devices. The camera devices are preferably mounted behind a windshield or a rear window in the interior of the motor vehicle.

[0036] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These show: Fig. 1 shows a schematic representation of a vehicle windscreen with possible mounting positions of camera devices of a stereo camera arrangement in the wiping area of ​​co-rotating windscreen wipers; Fig. 2 shows a schematic representation of the vehicle windscreen with possible mounting positions of the camera devices in the wiping area of ​​counter-rotating windscreen wipers; Fig. 3 shows a first embodiment of the stereo camera arrangement; Fig. 4 shows a second embodiment of the stereo camera arrangement; Fig. 5 a third embodiment of the stereo camera arrangement.

[0037] Corresponding parts are provided with the same reference numerals in all figures.

[0038] A stereo camera arrangement 1 for a motor vehicle 2 is proposed. The stereo camera arrangement 1 comprises at least a first and a second camera device 3, 4, and optionally a third to n camera devices for calculating distances using the stereo effect. The camera devices 3, 4, 6 can be configured with identical or alternatively with different optics.

[0039] The stereo camera arrangement comprises at least or exactly two separate, thus in particular separate, independently positionable holding devices, via which the at least first and second camera devices 3, 4 can be or are attached independently of one another to an inner side of a vehicle window 5 of the motor vehicle 2. In this exemplary embodiment, the vehicle window 5 is the windshield; as an exemplary alternative, the vehicle window 5 can be a rear window.

[0040] The free positioning of the camera devices 3, 4 allows for material savings and smaller designs compared to a one-box design, enabling a wide range of design and arrangement options. Another notable advantage is the ability to significantly increase the base widths between the camera devices 3, 4, 6 compared to a one-box design, allowing for greater accuracy in distance measurement. Furthermore, a simplified combination of two to n camera devices 3, 4, 6, n is feasible for reliable distance calculation to objects.

[0041] In the Fig. 1 and Fig. 2 shows purely exemplary different mounting positions P for the freely positionable first and second camera devices 3, 4, optionally additionally for the third or further camera devices 6, n on the inside of a vehicle window 5.

[0042] The camera equipment should be placed in the wiping area, for example. Fig. 1 shows possible mounting positions of the camera devices in the wiping area of ​​unidirectional windscreen wipers, in the Fig. 2 in the wiping area of ​​counter-rotating windscreen wipers.

[0043] The first and second camera devices 3, 4 can be arranged in different vehicle window areas P1, P2, P3, P4 and / or offset in height from one another on the inside of the vehicle window 5. In this context, a vehicle window area P1, P2, P3, P4 is understood to mean, in particular, one of the four corner areas P1, an upper end area P2, such as behind the rearview mirror, a lower end area P3, such as behind the cockpit cover, or one of the lateral end areas P4 of the vehicle window. For example, the first and second camera devices 3, 4 are arranged with a lateral base distance of half a meter from one another.

[0044] For example, at least one of the camera devices 3, 4, 6, n is or is mounted in the lower end region P3 behind the cockpit cover on the side facing the windshield 5. The at least one further camera device 3, 4, 6, n is or is mounted behind the rearview mirror on the side facing the windshield 5.

[0045] Thus, purely by way of example, it is possible to install at least one of the camera devices 3, 4, 6, n in the first of the two end areas P4 and at least the further camera devices 3, 4, 6, n in the second of the two end areas P4, so that full space utilization occurs and consequently the measuring capability of the object distances is increased compared to installation in the same vehicle window area.

[0046] The Fig. 3 to 5 show possible construction variants of the stereo camera arrangement 1 with the camera devices that can be mounted independently of one another on the inside of the vehicle window and thus freely positioned.

[0047] In Fig. Figure 3 shows a first exemplary embodiment of the stereo camera arrangement 1 with the first and second camera devices 3, 4, wherein the first camera device 3 is configured as a satellite camera and the second camera device 4 is configured as an intelligent camera. For example, the second camera device 4 comprises an image evaluation unit 7 configured to evaluate a distance to an object using the images captured by the camera devices 3, 4. With an intelligent camera device plus satellite, there is thus the possibility of a standardized intelligent mono camera, which can be supplemented by a satellite camera.

[0048] In Fig. Figure 4 shows a second exemplary embodiment of the stereo camera arrangement 1 with the first and second camera devices 3, 4, wherein the first and second camera devices 3, 4 are each configured as a satellite camera. For example, the stereo camera arrangement 1 is provided with, or connectable to, an image evaluation unit 7, which is configured to evaluate a distance to an object using the images captured by the camera device. The image evaluation unit 7 is, for example, a central ECU.

[0049] In Fig. 5 shows, as a third embodiment, the stereo camera arrangement 1 with a possible combination of three camera devices 3, 4, 6, designed as satellite cameras and an image evaluation unit 7.

[0050] A first of the camera devices 3, 4, 6, e.g. the first camera device 3, is designed, for example, as a wide-angle camera with a horizontal and / or vertical angle of view of + / - 50 degrees to the optical axis.

[0051] For example, the camera device 3 has an image recording sensor with a resolution of at least one megapixel and / or of at most two megapixels.

[0052] A second of the camera devices 3, 4, 6, e.g., the second camera device 4, is, for example, a high-resolution wide-angle camera 4 configured with a horizontal and / or vertical angle of view of + / - 50 degrees to the optical axis. For example, the second camera device 4 has an image recording sensor with a resolution of at least three megapixels, in particular of at least five megapixels, specifically of at least seven megapixels. As an exemplary alternative, the second camera device 4 can be configured as a wide-angle camera with non-linear optics, which, for example, enables at least or exactly two different resolutions. For example, a central image section of the images to be recorded or recorded by the second camera device 4 has at least twice the resolution of a peripheral image section of the images to be recorded or recorded.

[0053] A third of the camera devices 3, 4, 6, e.g., the third camera device 6, comprises, for example, an optical system configured with a horizontal and / or vertical angle of view of, e.g., at most + / - 15 degrees to the optical axis.

[0054] The camera devices 3, 4, 6 according to the Fig. The exemplary embodiment shown in Figure 5 enables, on the one hand, distance evaluation to objects even at great distances, e.g., for automated driving, while, on the other hand, achieving the resolution required for long-range vision. Thus, the opposing requirements of capturing the central area with a long range and capturing a wide-angle range, e.g., for cross-traffic detection, are reliably implemented with the stereo camera arrangement 1 according to the invention.

[0055] Of course, a different one than the one for Fig.The combination of different optics, image recording sensors, and base widths described in Figure 5 is conceivable. If the third camera device 6 is, for example, a surround-view outdoor camera, it is preferably provided that the third camera device 6 is designed as a wide-angle camera.

Claims

[1] Stereo camera arrangement (1) for a motor vehicle (2) comprising at least one first and one second camera device (3, 4), characterized by at least two separate mounting devices by which the at least first and second camera devices (3, 4) can be attached independently of each other to an inside of a vehicle window (5) of the motor vehicle (2), wherein the first camera device (3) is designed as a satellite camera and the second camera device (4) is designed as an intelligent camera, wherein the intelligent camera includes an image evaluation unit which is designed to evaluate a distance to an object by means of the images taken by the camera devices. [2] Stereo camera arrangement (1) according to claim 1, characterized by that at least the first and second camera devices can be mounted at different heights from each other on the inside of the vehicle window. [3] Stereo camera arrangement (1) according to claim 1 or 2, characterized by , that the camera devices can each be installed in one of the four corner areas (P1), in an upper end area (P2), in a lower end area (P3) or in one of the side end areas (P4) of the vehicle window (5). [4] Stereo camera arrangement (1) according to any one of the preceding claims 1 to 3, characterized by at least a third camera device (6), wherein an image evaluation unit (7) is designed to evaluate a distance to an object located in a first distance range by means of the images taken by the first and second camera devices (3, 4) and a distance to an object located in a second distance range by means of the images taken by the second and third camera devices (4, 6). [5] Stereo camera arrangement (1) according to claim 4, characterized by, that the first and second camera arrangements (3, 4) are configured as a wide-angle camera comprising a wide-angle optic with a horizontal and / or vertical viewing angle of + / - 50 degrees to the optical axis, wherein the second and third camera arrangements (4, 6) each have a high-resolution image acquisition sensor with a resolution of at least five megapixels in at least sections. [6] Stereo camera arrangement (1) according to one of the preceding claims 4 or 5, characterized by at least one further mounting device by which the third camera device (6) can be attached to the inside of the vehicle window (5) of the motor vehicle (2) independently of the first and second camera devices (3, 4). [7] Stereo camera arrangement (1) according to one of the preceding claims 4 or 5, characterized by , that the third camera device (6) is an outdoor camera of a camera surround view system. [8] Motor vehicle (2) with at least one stereo camera arrangement (1) according to one of the preceding claims, characterized by the at least two separate holding devices by which the at least first and second camera devices (3, 4) are attached independently of each other to an inside of a vehicle window (5) of the motor vehicle (2).

Images