Vehicle and method for its operation

Abstract

The invention relates to a vehicle (1) comprising at least one gated camera (3) directed forward in a longitudinal direction (x) and at least one light source (4) synchronized therewith, wherein a liquid lens (7) is arranged in an optical path in front of an image sensor (6) of the gated camera (3). The invention further relates to a method for operating the vehicle (1), wherein a focus (x focus ) of the liquid lens (7) is adjusted gate-specifically.

Description

[0001] The invention relates to a vehicle according to the preamble of claim 1 and a method for operating a vehicle according to the preamble of claim 5.

[0002] In the future, there will be an increasing number of automated vehicles, such as trucks and cars, on highways and other roads.

[0003] Such vehicles locate themselves using sensors (typically lidar, camera, radar) and map data in the existing infrastructure and adapt their driving behavior to other road users measured by the sensors.

[0004] These sensors have measurement characteristics determined by the sensor type, design, and physical constraints. Typically, the installed sensors perform various tasks. For example, the lidar measures a traffic-relevant area in front of the vehicle in three dimensions. At the same time, data from a camera is used to determine the semantics of the viewed scene and to detect traffic signs and traffic lights.

[0005] Derived requirements determine sensor parameters such as base width, focal length, aperture angle, pixel density, sensor type (color or monochrome), etc.

[0006] So-called gated cameras are well known in the art. Gated cameras are typically used for nighttime applications.

[0007] In nighttime applications, light is typically transmitted and received by the camera. Large apertures are advantageous for capturing as many photons as possible and thus resolving weakly reflective textures at great distances. A large aperture also results in a shallow depth of focus.

[0008] When shooting multiple gates at different distances, a fixed focus is a compromise, resulting in blur at some distances. A smaller aperture reduces light sensitivity but improves depth of field.

[0009] US 2016 / 0266392 A1 describes an apparatus, a system, and a method for microscopy. The apparatus, the system, and the method include a stage configured to receive an article; a tunable gradient-index acoustic refractive (TAG) lens having a first aspect positioned to image the received article, the first aspect of the TAG lens being configured to have an optical power profile according to an operating frequency of the TAG lens; one or more lenses configured to magnify an image of the received article at a viewpoint; and at least one pulsed light source configured to illuminate the received article and pulse at one or more points within the optical power profile of the TAG lens.

[0010] The invention is based on the object of providing a novel vehicle and a novel method for operating a vehicle.

[0011] The object is achieved according to the invention by a vehicle having the features of claim 1 and a method for operating a vehicle having the features of claim 5.

[0012] Advantageous embodiments of the invention are the subject of the subclaims.

[0013] A vehicle is proposed, comprising at least one gated camera oriented forward in a longitudinal direction and at least one light source synchronized therewith. According to the invention, a liquid lens is arranged in an optical path in front of an image sensor of the gated camera.

[0014] In one embodiment, a camera control module is provided that is configured to adjust a focus of the liquid lens in a gate-specific manner.

[0015] In one embodiment, the vehicle is designed as a commercial vehicle or bus.

[0016] In one embodiment, the vehicle is designed as a semi-autonomous or fully autonomous vehicle.

[0017] According to one aspect of the present invention, a method for operating a vehicle as described above is proposed, wherein a focus of the liquid lens is adjusted in a gate-specific manner.

[0018] The inventive solution enables a better signal-to-noise ratio with simultaneously improved focus adjustment and improved light output and / or sensitivity. Thanks to the improved image signals, subsequent image processing enables earlier detection and classification of driving-relevant objects in adverse lighting and / or weather conditions.

[0019] This also allows higher speeds to be achieved thanks to improved visibility and the associated driving safety.

[0020] Embodiments of the invention are explained in more detail below with reference to drawings.

[0021] Showing: Fig. 1 a schematic view of a vehicle with a gated camera on a roadway, Fig. 2 a schematic view of a liquid lens arranged in an optical path in front of the gated camera, Fig. 3 a schematic view of an example with three gates, Fig. 4 a schematic view of a camera arrangement comprising the gated camera, a light source, a camera control module and a detection module.

[0022] Corresponding parts are provided with the same reference numerals in all figures.

[0023] Fig. 1 is a schematic view of a vehicle 1, in particular a commercial vehicle, on a roadway 2. The vehicle 1 can be designed as a semi-autonomous or fully autonomous vehicle 1. The vehicle 1 has at least one gated camera 3, whose field of view 5 (frustum) can be oriented in a longitudinal direction x, i.e., forward, and at least one light source 4, for example, a laser light source, for pulsed illumination of the roadway 2. The light source 4 is arranged spatially offset from the gated camera 3, for example, offset in a vertical direction and / or in a transverse direction.

[0024] The gated camera 3 (e.g., from Brightway Vision) combines the time-of-flight of the emitted light with the tight closing times of a pixel gate array of an image sensor 6 embodied as a CMOS image sensor, which is time-synchronized with the light source 4, thus generating images B1, B2, B3, referred to as "gates." "Gates" are images B1, B2, B3 that represent only the light that has traveled the distance between light source 4 and image sensor 6 within a predetermined time interval T1, T2, T3 (closing time of the image sensor 6), and thus specific distance ranges EB1, EB2, EB3. By setting a delay between illumination and image capture, the environment can be divided into individual images B1, B2, B3 that depict only a specific distance range EB1, EB2, EB3. The gated camera 3 has advantages in atmospheric disturbances because it implicitly suppresses reflections outside the gates (backscatter avoidance).

[0025] The Gated Camera 3, for example, uses global shutter technology and VSCEL light pulse illumination to capture 90 images per second.

[0026] This high frequency enables new measurement approaches. The terms gate and slice are used synonymously here.

[0027] Gated cameras 3 can be used to detect obstacles H1, H2, H3 on a roadway 2. This makes an important contribution to the safe operation of autonomous vehicles 1. For this purpose, the light sources 4 used are spatially separated and offset from the image sensor 6, resulting in a shadowing of the area behind an obstacle H1, H2, H3 on the roadway 2, which appears significantly larger in image B1, B2, B3 than the actual object or obstacle H1, H2, H3 is shown in image B1, B2, B3. This effect and the shadow shape caused by multiple light sources 4 significantly facilitate the detection of obstacles H1, H2, H3 in image B1, B2, B3.

[0028] According to the present invention, it is proposed to arrange a liquid lens 7 in the optical path of a gated camera 3.

[0029] A liquid lens 7 in the optical path allows the gated camera 3 to adjust its focus to a specific gate. This allows the focus to be optimally adjusted depending on the gate.

[0030] Fig. Figure 2 is a schematic view of a liquid lens 7 arranged in an optical path in front of the image sensor 6 of the gated camera 3 (shown in Fig. 1) is arranged. b Size of a pixel d aperture f focal length Projection of the point P0+ P1 projection of point P0 Projection of the point P0− Point with maximum distance that is still sharply projected onto the image sensor 6 P0 Point with optimal distance, which is projected sharply onto the image sensor 6 Point with minimum distance that is still sharply projected onto the image sensor 6 x Distance from image sensor 6 in longitudinal direction maximum distance of a point that is still projected sharply with respect to the pixel size X0 optimal distance of a point that is projected sharply minimum distance of a point that is still projected sharply with respect to the pixel size x focus set focal length or set focus of the liquid lens 7 ΔX0−=X0−X0−=X0(X0−f)X0+fdb−f ΔX0+=X0+−X0

[0031] The depth of field DOF is calculated as follows: DOF=ΔX0−+ΔX0+

[0032] For each gate passing through a starting position x start and an end position x end with respect to the plane of the image sensor 6, [X0−;X0+] The focus of the liquid lens 7 is then set to x focus =X0 set.

[0033] Fig. Figure 3 is a schematic view of an example with three gates. At a time t1, for a first gate defined by a starting position x start_1 and an end position x end_1 with respect to the plane of the image sensor 6 (shown in Fig. 1), the focus of the liquid lens 7 (shown in Fig. 1) on x focus_1 set to a depth of field DOF1 of the gated camera 3 in the range from the start position x start_1 to the end position x end_1 At a time t2, for a second gate, which is defined by a starting position x start_2 and an end position x end_2 with respect to the plane of the image sensor 6, the focus of the liquid lens 7 on x focus_2 set to a depth of field DOF2 of the gated camera 3 in the range from the start position x start_2 to the end position x end_2 At a time t3, a third gate, which is defined by a starting position x start_3and an end position x end_3 with respect to the plane of the image sensor 6, the focus of the liquid lens 7 on x focus_3 set to a depth of field DOF3 of the gated camera 3 in the range from the start position X start_3 to the end position X end_3 to achieve.

[0034] Fig. 4 is a schematic view of a camera arrangement 10 comprising the gated camera 3, the light source 4, a camera control module 11 and a capture module 12 for the gated camera 3, from which captured images can be fed to an image processing unit 13. List of reference symbols 1 vehicle 2 lanes 3 Gated camera 4 Light source 5 viewing volume 6 image sensor 7 Liquid lens 10 Camera arrangement 11 Camera control module 12 Recording module 13 Image processing b Size of a pixel B1, B2, B3 Image d aperture EB1, EB2, EB3 distance range f focal length H1, H2, H3 obstacle Projection of the point P0+ P1 projection of point P0 Projection of the point P0− Point with maximum distance that is still sharply projected onto the image sensor 6 P0 Point with optimal distance, which is projected sharply onto the image sensor 6 Point with minimum distance that is still sharply projected onto the image sensor 6 T1, T2, T3 time interval t1, t2, t3 time point x Longitudinal direction, distance from the image sensor in the longitudinal direction maximum distance of a point that is still projected sharply with respect to the pixel size X0 optimal distance of a point that is projected sharply minimum distance of a point that is still projected sharply with respect to the pixel size xstart_1 , x start_2 Starting position X end-1 , x end_2 Final position x focus set focal length or set focus of the liquid lens 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] US 2016 / 0266392 A1

[0009]

Claims

[1] Vehicle (1) comprising at least one gated camera (3) directed forward in a longitudinal direction (x) and at least one light source (4) synchronized therewith, characterized by that a liquid lens (7) is arranged in an optical path in front of an image sensor (6) of the gated camera (3). [2] Vehicle (1) according to claim 1, characterized by a camera control module (11) configured to control a focus (x focus ) of the liquid lens (7) gate-specifically. [3] Vehicle (1) according to claim 1 or 2, characterized by that the vehicle (1) is designed as a commercial vehicle or bus. [4] Vehicle (1) according to one of the preceding claims, characterized by that the vehicle (1) is designed as a partially autonomous or fully autonomous vehicle (1). [5] Method for operating a vehicle (1) according to one of the preceding claims, characterized by that a focus (x focus) of the liquid lens (7) is adjusted gate-specifically.

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