EP4128160A1

EP4128160A1 - Method for determining a pose of an object, method for controlling a vehicle, control unit and vehicle

Info

Publication number: EP4128160A1
Application number: EP21715163.8A
Authority: EP
Inventors: Tobias KLINGER; Dennis Sabelhaus; Oliver WULF
Original assignee: ZF CV Systems Global GmbH
Current assignee: ZF CV Systems Global GmbH
Priority date: 2020-03-26
Filing date: 2021-03-22
Publication date: 2023-02-08
Also published as: WO2021191099A1; US20230196609A1; DE102020108416A1

Abstract

The invention relates to a method for determining a pose (PO) of an object (O) relative to a vehicle (1), wherein the object (O) has at least three markers (M1, M2, M3, M4) and is captured by at least one camera (4) on the vehicle (1), comprising the following steps: – capturing the markers (M1, M2, M3, M4) by means of the camera (4) and generating an image (B), wherein a marker representation is assigned to the markers (M1, M2, M3, M4) in the image; – determining marker positions and/or marker vectors of the markers (M1, M2, M3, M4) on the captured object (O); – determining a transformation matrix (T) depending on the marker positions and/or the marker vectors and depending on the marker representations, wherein the transformation matrix (T) maps the markers (M1, M2, M3, M4) on the object (O) to the marker representation in the image (B); – determining an object plane (OE) formed by the markers (M1, M2, M3, M4) on the object (O) in a second coordinate system (K2) depending on the transformation matrix (T) determined, wherein the second coordinate system (K2) is fixed with respect to the vehicle in order to determine the pose (PO) of the object (O) relative to the vehicle (1). The invention provides for the at least three markers (M1, M2, M3, M4) on the object (O) to be of three-dimensional extent and to be assigned to two-dimensional marker representations in the image (B).

Description

Method for determining a pose of an object, method for controlling a vehicle, control unit and vehicle

The invention relates to a method for determining a pose of an object, a method for controlling a vehicle, and a control unit and a vehicle for performing the method.

It is known from the prior art how a vehicle can be brought closer to an object with the aid of one or more cameras, wherein the object can be a trailer, for example. The detection of the environment for estimating depth information with regard to the object can be done in 2D or 3D.

For this purpose, a stereo camera can be used, for example, which recognizes the trailer or two-dimensional or flat markers on the trailer or on components of the trailer and derives depth information therefrom. This is described by way of example in DE 102016011 324 A1, DE 10 2018 114730 A1, WO 2018/210990 A1 or DE 102017 119968 A1. A position and an orientation, i.e. a pose, of the respective object relative to the camera or the towing vehicle can be derived from this. Depending on this, for example a kink angle or a distance can be determined. The pose can also be determined with a mono camera by localizing at least three markers, which are preferably applied flatly on the object, in the image and, knowing the marker positions on the object, determining a transformation matrix from which the pose of the object on which they are located can be derived.

According to DE102018210340A1 it is also provided to determine a distance to a swap body by adding a size of three applied markers is compared with stored sizes for these markers. The markers are coded accordingly so that their size can be determined in advance using a camera. An angular offset can also be estimated from a relative position of individual markers to one another.

Detection of a kink angle by means of a camera is also described in US 2014200759 A, a flat marker on the trailer being observed over time from the towing vehicle and the kink angle being estimated therefrom. JP 2002012 172 A, US2014277942A1, US 2008231 701 A and US 2017106796 A also describe knee angle detection as a function of flat markers. In US 2006293800 A, coupling points can carry a marker to facilitate automatic detection. The marker can have a special color, texture or wave reflection property. DE 102004025252 B4 also describes how to determine the kink angle by transmitting radiation from a transmitter onto a semicircular or hemispherical reflector and then detecting the radiation reflected therefrom. DE 10302545 A1 also describes the detection of a clutch using an object recognition algorithm. EP 3 180769 B1 also describes how to use cameras to record a rear side of a trailer and to recognize traceable features from the image, e.g. an edge or corner. These are then tracked over time, in particular to infer a bend angle between the pulling vehicle and the trailer. This means that no specially applied markers are used.

US 2018039266 A also describes how to access information from a two-dimensional barcode or QR code. In DE 10 2016 209 418 A1, a QR code can also be read out with a camera in order to identify the trailer and to pass on trailer parameters to a reversing assistant. Alternatively or in addition, an am RFID reader located on a trailer read out an RFID transponder that is attached to the towing vehicle, for example in the form of a label. This allows a position of the QR code or the RFID transponder to be calculated. An orientation is not determined. A solution using radio-based transponders is also provided in W01 8060192A1. In DE 10 2006 040 879 B4, RFID elements are also used on the trailer for triangulation when approaching Fier.

In WO 2008064892 A1 an observation element is provided which has at least three auxiliary points or measuring points that can be recognized by a camera. The coordinates or vectors of the centers of gravity of the auxiliary points are determined from geometric considerations, and from this the coordinates of the measurement points relative to the camera or the image sensor. A kink angle can be determined from this.

The disadvantage of known methods is that these methods or systems are either very complex or that the marker cannot be reliably detected under different environmental conditions. For example, flat markers cannot be reliably detected in the dark and / or under extreme or flat flashing angles, which means that the pose of the object or the articulation angle of the trailer cannot be reliably determined relative to the towing vehicle.

The object of the invention is therefore to provide a method which enables a simple and reliable determination of the pose of an object and a subsequent processing or use of this pose for controlling the vehicle. The object of the invention is also to provide a control unit and a vehicle for carrying out the method.

This object is achieved by a method for determining the pose of an object, a method for controlling a vehicle, a control unit and solved a vehicle according to the independent claims. The subclaims indicate preferred further training.

According to the invention is therefore a method for determining a pose, ie a combination of a position and an orientation, an object with an object width and an object height relative to a one-part or multi-part vehicle, the object and the vehicle ge against each other are movable, and the object has at least three markers, preferably at least four markers, namely spatially extended markers or markers with a spatial geometry, for example with a spherical or cylindrical or cuboid geometry. The at least three, preferably at least four markers lie in the same object plane on the object and no line can be laid through the at least three, preferably at least four markers. It is assumed here that the object plane described by the marker also lies approximately on the respective object, so that the pose can be estimated from this.

The object is captured by at least one camera on the vehicle and at least the following steps are carried out:

- Detecting the at least three spatially extended markers with the camera and generating an image, the at least three spatially extended markers in the image each being assigned a marker image;

Determination of marker positions and / or marker vectors of the spatially extended markers on the detected object, this being indicated, for example, in a first coordinate system that is fixed to the marker or moves with the spatially extended markers;

- Determination of a transformation matrix (homography) as a function of the marker positions and / or the marker vectors and as a function of the marker images, the transformation matrix being the spatially extended markers on the object or the first coordinate system on the Marker mapping in the image of the camera on the vehicle or a Bildko ordinatensystem maps; and

- Determination of an object plane formed by the spatially extended marker on the object in a second coordinate system as a function of the determined transformation matrix, the second coordinate system being fixed to the vehicle for determining the pose of the object relative to the vehicle from the relative position between the object plane and the Image level.

At least three markers are required to determine the transformation matrix, in which case - possibly with further additional information - a transformation matrix can at least be estimated, possibly with heuristic methods. However, it is more precise if four or more markers are present on the respective object, since a clearly defined transformation matrix or flomography matrix can then be determined using known methods.

According to the invention, it was recognized that spatially extended markers can still be detected very well by the camera of the vehicle even at large bending angles or at extreme viewing angles, because they protrude from the object plane and can thus be better perceived. This provides a method for determining both the position and the orientation of the object that is almost invariant to the viewing angle. This is also made possible by monocular image processing so that stereo cameras do not necessarily have to be used to obtain depth information on the object from which the pose can be geometrically derived. This simplifies the process and the costs can be kept low. The spatial markers can be displayed on the image plane with high contrast even in poor visibility or ambient conditions, so that the marker images can be used in different environments. Practice conditions and visual conditions allow sufficient information to be determined about the object level.

Thus, by using this method, a vehicle can also be reliably controlled according to the invention, the vehicle

- Within the framework of an assist function based on the articulation angle, depending on a articulation angle derived from the determined pose of the object, between a towing vehicle and a trailer of a multi-part vehicle and / or a change in the articulation angle is controlled, or

- In the context of a coupling assistance function as a function of a normal distance and / or reference distance derived from the determined pose of the object between the towing vehicle as a vehicle and a trailer to be coupled as an object on which the markers are arranged. the towing vehicle is then controlled manually or automatically in such a way that a second coupling point on the towing vehicle, for example a (fifth wheel) coupling, approaches a first coupling point on the trailer to be coupled, for example a kingpin or a drawbar, and the two coupling points at one common pivot point can be coupled together, or

- As part of a distance assistance function as a function of a normal distance and / or reference distance derived from the determined pose between the towing vehicle as a vehicle and a building as an object on which the markers are arranged, for example a loading ramp or a garage door, or a foreign vehicle is controlled as the object on which the markers are arranged. The method for determining the pose of the object and / or also the control of the vehicle are carried out on a control unit according to the invention in a vehicle. It is preferably also provided that at least one of the at least three markers

- Is illuminated from the inside and / or behind, for example via a light source arranged in a marker interior of the at least three markers, the respective marker then being at least partially transparent or light-permeable, and / or

- Is illuminated and / or illuminated from the outside, for example via ei ne ambient light, preferably on the vehicle and / or on the object, and / or

- Has a self-luminous coating, for example a fluorescent coating, or the like.

As a result, the spatially extended markers can advantageously be used to ensure that the object plane or the pose of the object can also be detected with high contrast in the dark. This means that the respective assistance functions can also be reliably carried out in the dark. The self-luminous coating or the fluorescent coating have the advantage that no energy sources are required on the object.

It is preferably also provided that the light source is controlled in at least one of the at least three markers and / or the ambient light as a function of a state of motion of the vehicle and / or the object. This saves energy, since the markers are actually only actively illuminated when this is absolutely necessary, for example when moving as part of one of the driver assistance functions.

Preferably it can furthermore be provided that - a color of the light source and / or the ambient light and / or a pulse duration of the light source and / or the ambient light as a function of ability of a distance between the vehicle and the object, and / or - a color of the light source and / or a pulse duration of the light source is set as a function of the marker position on the object. Accordingly, the markers can be illuminated in a targeted manner in order to additionally assist the driver, so that the driver can for example use a display device to see how far he can drive backwards before the respective object or the object plane defined by the marker is reached. Even in the case of adjacent objects, it is possible to distinguish between objects in the dark by means of color coding or flashing light coding. Such a color coding can also be achieved by the self-luminous coating, which can be applied to the respective marker in predefined colors depending on the marker position on the object.

It is preferably also provided that the light sources in at least one of the at least three markers are supplied with energy from an energy source, for example a solar panel, on the object. As a result, the illumination of the markers on the object is independent of the presence of a vehicle, for example in the non-coupled state. The markers on the object, for example on the trailer, can thus be individually illuminated when parking in a depot.

It is also preferably provided that at least one of the at least three markers is formed by a clearance light or outline lighting on the edges of the object. This means that existing elements on a trailer can be used twice and the installation of additional markers can be omitted. For this purpose, it is only necessary to specify which clearance lights are to function as markers, and this can be done via the respective marker positions or marker vectors. Knowing this, the pose of the trailer can be determined from the object plane as a function of the mapping of the respective selected clearance lights be determined. Since the clearance lights are normally located on the edge of the trailer, a contour of the trailer can be generated from them in a simple manner.

It is preferably also provided that the ambient light emits visible and / or invisible radiation onto the markers and that the markers have a reflective coating. As a result, good visibility can be achieved in a variable manner.

It is preferably also provided that a QR code and / or a barcode and / or an Aruco marker is applied to the surface of at least one of the markers or adjacent to at least one of the markers and the QR code and / or the barcode and / or the Aruco marker is captured by the camera. This means that coded information can be read out without using separate data transmission. In this way, for example, the marker positions and / or the marker vectors in the vehicle can be determined in a simple manner, which are necessary for determining the transformation matrix in order to be able to infer the pose from the transformation matrix. Furthermore, an object width and / or an object height can be coded on the respective code or marker in a simple manner so that this information can also be accessed from the vehicle without further data transmission or any other reading in of the data to need.

The object width of the object and / or the object height of the object and / or a first reference point on the object, e.g. a first coupling point, kingpin on a trailer, can, however, preferably also be determined as a function of the spatial arrangement of the recognized markers on the object / or at least be estimated. Accordingly, a specific coding can also be achieved in this way without an additional Data transfer is necessary.

Furthermore, it can be provided that the object width of the object and / or the object height of the object and / or a first reference point on the object and / or the marker positions and / or the marker vectors via a communication unit on the object, for example in the markers, preferably transmitted to the vehicle via Bluetooth or RFID. This means that wireless data transmission can be used, which makes it easier to record the respective geometric information.

It is preferably also provided that the camera additionally records surface markings which are arranged adjacent to at least one of the markers on the object, the position of the object being redundantly determined from the surface markings recorded. The area markings can for example also be used for a rough adjustment or rough determination of the pose if, for example, the determination of the pose from the spatial markers is still too imprecise because, for example, the resolution of the camera is too low. The area markings can accordingly be resolved to a greater extent without great effort, the area markings advantageously also being illuminated in the dark due to their proximity to the spatial markers, so that a double function can be achieved through the illumination. As a result, the extent of the spatial markers can be kept small, since these are only necessary for fine adjustment, for example during a coupling process or during another approach process.

It is also preferably provided that the area markings and / or the markers are at least partially arranged at the edges of the object and an object width of the object and / or an object height of the object is derived from the captured image of the camera. Because the markers or area markings - each for themselves or in combination with one another - are arranged at the edges, a contour can be determined from which the respective object width or the object height can also be estimated.

It is preferably also provided that the vehicle is in one piece and the object is not connected to the vehicle, the vehicle moving relative to the object and the object being a trailer to be coupled or a building, for example a loading ramp or a garage door, or is a third-party vehicle. As a result, a wide variety of objects can be recognized with this method, which at least in some areas have a flat character and their pose relative to the vehicle, i.e. distances (translational degree of freedom) and / or angles (rotational degree of freedom), for example for a coupling assistance, parking assistance, approach assistance, or the like is relevant.

It is preferably also provided that the vehicle is in several parts, i.e. has at least one towing vehicle and at least one trailer, and the camera is arranged on a towing vehicle and / or on a trailer coupled to it, with

- The object is connected to the multi-part vehicle in the form of a trailer coupled to the towing vehicle, the trailer moving rela tively to the towing vehicle at least temporarily or pivoting in relation to it, or

the object is not connected to the multi-part vehicle, the object being a building, for example a loading ramp or a garage door, or a third-party vehicle on which the markers are respectively arranged. This object can then be in front of or next to the towing vehicle or behind or next to the coupled trailer, with the camera being aligned accordingly to the part of the environment. It is preferably also provided that the image of the camera is displayed on a display device, the image from the display device being a normal distance and / or a reference distance (as well as their lateral and vertical components) and / or a contour of the object and / or control information and / or an articulation angle between the towing vehicle and the trailer and / or a first coupling point (e.g. king pin, drawbar) and / or a second coupling point (e.g. (saddle) coupling) and / or a trailer identifier and / or a loading space image and / or a trailer center axis determined as a function of the markers and / or a towing vehicle center axis, or axles lying parallel to it, are superimposed. In this way, the following information can also be displayed, especially from the po se, so that the driver can perceive this and can react to it in a more targeted manner within the framework of the respective assistance functions. The driver can, for example, take countermeasures manually if the indicated articulation angle is too high or observe the coupling process and manually influence it.

The invention is explained in more detail below using an exemplary embodiment. Show it:

1 shows a two-part vehicle with markers and cameras;

2 shows an image recorded by the camera;

3 shows a detailed view of a front side of a trailer as

Object with markers;

4 is a schematic view of a two-part vehicle; and

5a, 5b, 5c detail views of markers and area markings. In Figure 1, a multi-part vehicle 1 from a train vehicle 2 and a trailer 3 is shown schematically, according to the embodiment shown, a camera 4 with a detection area E is arranged on each of the two vehicle parts 2, 3. On the towing vehicle 2 there is a towing vehicle camera 42 with a towing vehicle detection area E2 which is oriented towards the trailer 3, and a trailer camera 43 with a rearward-facing trailer detection area E3 is arranged on the trailer 3. The cameras 4; 42, 43 each output camera data KD.

The vehicle 1 can be designed in several parts, for example as a truck with a truck and drawbar trailer or turntable trailer or as a tractor-trailer with a tractor unit and semi-trailer (see FIG. 1). It is also possible to provide more than just one trailer 3, for example in the case of a EuroCombi or a road train. In principle, however, the vehicle 1 can also only be in one piece. The orientation of the camera 4 is chosen depending on the application. For example, an omnidirectional camera, a fisheye camera or a telephoto lens camera or other types of cameras can be used as the camera 4.

The respective camera data KD are generated as a function of an environment U around the vehicle 1, which is located in the respective detection area E and which is imaged on an image sensor 4a of the respective camera 4. An image B of image points BPi with image coordinates xB, yB (see FIG. 2) can therefore be created from the camera data KD, an object point PPi in the vicinity U being assigned to each image point BPi. The object points PPi belong to objects O that are in the vicinity U. The image B can also be displayed to the driver of the vehicle 1 via a display device 8. The camera data KD of the respective camera 4 are transmitted to a control unit 5 in the respective vehicle part 2, 3 or to a higher-level control unit 5 of the vehicle 1, which is designed as a function of the camera data KD from one or more recorded images B to extract marker images M1a, M2a, M3a, M4a, for example by means of edge detection. A marker M1, M2, M3, M4 in the vicinity U is assigned to each marker image M1a, M2a, M3a, M4a. Furthermore, the respective control unit 5 is designed to determine an object plane OE in which the respective markers M1, M2, M3 , M4 are arranged in the vicinity U.

It is assumed that at least three, preferably at least four markers M1, M2, M3, M4 are provided and that these are at least four markers M1, M2, M3, M4 as shown in FIG. 3, in one plane and not on one Line are located on the object O to be recognized in the environment U, for example on a preferably flat front side 3a of the trailer 3. It is assumed that the object plane OE defined by the markers M1, M2, M3, M4 is actually the object O in the relevant area Describes the area, ie here on the flat front side 3a, at least approximately in an abstract way.

The four markers M1, M2, M3, M4 can then be detected by the towing vehicle camera 42, for example. However, more than four markers M1, M2, M3, M4 can also be provided on the respective object O, with at least four markers M1, M2, M3, M4 being necessary to determine the transformation matrix T in order to obtain a clearly determined transformation matrix T. . In principle, however, a transformation matrix T ab can also be estimated with only three markers M1, M2, M3 and possibly further additional information, possibly using heuristic methods, which may then be less precise. About the determined or estimated transforma- mation matrix T starting from the towing vehicle 2 both a position (translational degree of freedom) and an orientation (rotational degree of freedom) or a combination thereof, ie a pose PO, of the trailer 3 in space relative to the towing vehicle camera 42 and thus also relative to the Towing vehicle 2 can be estimated, as explained in more detail below:

For the marker images M1a, M2a, M3a, M4a, image coordinates xB, yB are first determined in the at least one recorded image B in an image coordinate system KB. Since the markers M1, M2, M3, M4 have a certain spatial extent and are therefore mapped flat in the image B, ie several image points BPi are assigned to a marker M1, M2, M3, M4, the center point of the respective marker can, for example -Image M1a, M2a, M3a, M4a is determined and its image coordinates xB, yB are further processed.

At the same time, the control unit 5 knows how the four markers M1, M2, M3, M4 are actually positioned on the object O, e.g. the front side 3a of the trailer 3, relative to one another in the object plane OE. Accordingly, a marker position P1, P2, P3, P4 or a marker vector V1, V2, V3, V4 can be specified for each marker M1, M2, M3, M4 (see FIG. 3). The marker vectors V1, V2, V3, V4 each contain first coordinates x1, y1, z1 of a first coordinate system K1 with a first origin U1, the marker vectors V1, V2, V3, V4 for the respective marker M1, M2, M3, M4 show. The first coordinate system K1 is fixed to the trailer or marker fixed, i.e. it moves with the markers M1, M2, M3, M4. The first origin U1 can lie in a fixed first reference point PB1 on the object O, for example in one of the markers M1, M2, M3,

M4 or in a first coupling point 6, in the case of an articulated truck as a multi-part vehicle 1, for example in a king pin 6a (see FIG. 1). From the image coordinates xB, yB of the four marker images M1a, M2a, M3a, M4a in the image coordinate system KB, the control unit 5 can now use the known marker vectors V1, V2, V3, V4 or marker positions P1, P2 , P3, P4 of the markers M1, M2, M3, M4 in the first coordinate system K1 a transformation matrix T can be derived. This transformation matrix T indicates how the individual markers M1, M2, M3, M4 as well as the object points PPi of the entire object plane OE, which according to FIG. 1 is parallel to the flat front side 3a of the trailer 3, on the image sensor 4a of the camera 4 and thus in image B in the current driving situation of vehicle 1. The transformation matrix T thus indicates how the object plane OE is mapped onto the image plane BE of the image sensor 4a in the current driving situation.

Accordingly, the transformation matrix T also contains the information on how the trailer-fixed or marker-fixed first coordinate system K1 is oriented relative to the image coordinate system KB, with both translational and rotational degrees of freedom being included, so that a pose PO (combination of position and orientation ) the object plane OE can be determined relative to the image plane BE. With knowledge of camera parameters, for example a focal length f, an aspect ratio SV of the image sensor 4a, which are stored, for example, on the control unit 5 or transmitted to it, a series of information can be derived from the transformation matrix T, which can be derived from different assistance functions Fi let use.

Since the transformation matrix T follows from the current driving situation of the vehicle 1, it contains, for example, a dependence on an articulation angle KW between the towing vehicle 2 and the trailer 3 and on a normal distance AN between the camera 4 or the image sensor 4a and the object plane OE . These can be determined when the position of the image sensor 4a or the image plane BE of the image sensor 4a is known in a camera-fixed or here also tractor-fixed second coordinate system K2. In addition, both the image plane BE with the individual image points BPi and the object plane OE can be expressed in second coordinates x2, y2, z2 of the coordinate system K2 fixed to the towing vehicle, from which the pose PO of the object O relative to the towing vehicle 2 can be determined.

This applies correspondingly to the normal distance AN, which specifies the perpendicular distance between the object plane OE and the image sensor 4a. If the position of the coordinate systems K1, K2 with respect to one another is known from the transformation matrix T or if the object plane OE can be specified in the second coordinate system K2, then the normal distance NA can be determined in a simple manner. Instead of the normal distance NA, however, a reference distance AR can also be determined, which is measured between a first reference point PR1 in the object plane OE, e.g. on the trailer 3 or on a loading ramp 11a, and a second reference point PR2 on the towing vehicle 2 ( see Fig. 4). If the reference points PR1, PR2 in the respective coordinate system K1, K2 are known, the reference distance AR can be determined from them with simple geometric considerations using the transformation matrix T.

A second origin U2 of the second coordinate system K2 can, depending on the application, be at a specified second reference point PB2 on the towing vehicle 2, for example in the image sensor 4a itself or in a second coupling point 7 on the towing vehicle 2, for example in a fifth wheel 7a of a tractor-trailer. The two coupling points 6, 7 thus define a common pivot point DP about which the towing vehicle 2 and the trailer 3 pivot with respect to one another when cornering.

The person skilled in the art will easily recognize here that the coupling points 6, 7 in a drawbar trailer or a turntable trailer or other Direct trailer types are to be adapted accordingly and a distance AN, AR and a kink angle KW as described from the transformation matrix T can also be determined for such trucks from geometric considerations.

In summary, the po se PO of the trailer 3 or the pose PO of any other objects O, which mark such markers M1, M2, M3, M4 with known marker vectors V1,

V2, V3, V4 or marker positions P1, P2, P3, P4 are determined who the. For this purpose, the image coordinate system KB is converted into the first coordinate system K1 by the transformation matrix T, whereby the object level OE can also be represented in the second coordinate system K2. From this, both translational measured variables, e.g. the distances AN, AR, and rotational measured variables, e.g. angles, between the towing vehicle 2 and the object plane OE of the respective object O, i.e. the pose PO, ab can be estimated.

In order to make the recognition of the markers M1, M2, M3, M4 more reliable, they each have a spatial geometry, preferably a spherical geometry, i.e. they are designed in the form of a sphere.

This advantageously ensures that the markers M1, M2, M3, M4 are always mapped as a circle in the recorded image B regardless of the viewing angle of the respective camera 4, ie form a two-dimensional projection of image points BPi on the image sensor 4a. As spheres, the markers M1, M2, M3, M4 are therefore invariant to the viewing angle. In principle, however, markers M1, M2, M3, M4 with other spatial geometries can also be used, for example hemispheres, cubes or cylinders, which can also be detected from different angles by the camera 4 with defined two-dimensional projections. As such markers M1, M2, M3, M4, for example, fixed clearance lights 21a or from These radiated outline lighting can be used, which may already be present on trailers 3.

Furthermore, there is the possibility of illuminating the markers M1, M2, M3, M4, preferably from the inside or the rear from a marker interior 20 with a corresponding light source 21 (see. Fig. 5a, 5b, 5c), for example an LED, which can be controlled via a lighting control 22 with a lighting signal SL. The respective marker M1, M2, M3, M4 is then at least partially transparent or translucent in order to enable the electromagnetic radiation to exit from the inside or from the rear. As a result, the markers M1, M2, M3, M4 can be detected with high contrast by the camera 4 from different angles, even in the dark. The markers M1, M2, M3, M4 or their light sources 21 are preferably supplied with energy via an energy source 23 in the trailer 3 or on the respective object O, wherein the energy source 23 can be charged by solar panels 23a.

In addition, it can be provided that the markers M1, M2, M3, M4 are illuminated by the lighting control 22 as a function of a movement state Z of the vehicle 1, the towing vehicle 2 and / or the trailer 3, or generally the respective object O. For this purpose, for example, a motion sensor 24 can be provided on the trailer 3 or generally on the object O with the markers M1, M2, M3, M4, which indicates the movement state Z of the vehicle 1, the towing vehicle 2 and / or the trailer 3, or the object O with the markers M1, M2, M3, M4 can detect. If the vehicle 1 or towing vehicle 2 moves in relation to the respective object O or the markers M1, M2, M3, M4, the light sources 21 can be supplied with energy by the light control 22 and thus made to glow. It can preferably also be provided that the light sources

21 depending on different lighting criteria from the lighting control

22 can be controlled. The lighting criteria can be the normal distance AN and / or the reference distance AR. Depending on this, the lighting control 22 can, for example, set different colors C for the lighting sources 21 and / or different pulse durations dt (flashing light) by frequency modulating the lighting signal SL. If the distance AN, AR is large, long pulse durations dt can be provided, and if the distance AN, AR is short, shorter pulse durations dt can be provided. A marker position P1, P2, P3, P4 of the respective marker M1, M2, M3, M4 on the respective object O can be taken into account as a further lighting criterion. For example, the lighting control 22 can illuminate a marker located at the top left in red and a marker located at the bottom right in blue. In this way, the driver can better distinguish between objects O lying next to one another, which each have markers M1, M2, M3, M4 for themselves, for example trailers 3 parked parallel to one another.

In principle, it is also possible to make the markers M1, M2, M3, M4 visible in other ways in the dark. For example, the markers M1, M2, M3, M4 can be provided on the surface with a self-luminous coating 27, for example a fluorescent coating 27a, or the markers M1, M2, M3, M4 can be made of a self-luminous material. As a result, no energy source is required on the respective object O, which has the markers M1, M2, M3, M4.

This provides a number of options for making the markers M1, M2, M3, M4 self-luminous. In principle, the markers M1, M2, M3, M4 can also be illuminated or illuminated from the outside, for example by an ambient light 25 on the towing vehicle 2 or on the respective vehicle 1, which is attached to a trailer 3, a loading ramp 11 a, or in general to the object O with the markers M1, M2, M3, M4 approximates so that the markers M1, M2, M3, M4 can also be made visible in the dark. The ambient light 25 can in this case emit radiation in the visible or invisible spectrum, for example ultraviolet, and illuminate the markers M1, M2, M3, M4 with it. The markers M1, M2, M3, M4 can also be provided with a corresponding reflective coating 26 in order to be able to reflect the radiation in the respective spectrum back to the camera 4 with high intensity. The ambient light 25 can, like the light source 21, be controlled as a function of the state of motion Z and other light criteria in order to e.g. to be illuminated depending on the normal distance AN and / or the reference distance AR or the state of movement Z.

This distinguishes the invention from conventional methods in which planar surface markings Mf alone or in combination with QR codes CQ and / or bar codes CB and / or Aruco markers CA are used to create a pose PO of the object plane OE of the object O to capture, the visibility of the area markings Mf under large viewing angles and is very limited in the dark. Despite these disadvantages, provision can be made for the spatially extended markers M1, M2, M3,

M4 to be combined with such area markings Mf (see Fig. 5). The surface markings Mf can also be illuminated in the dark by the adjacent light sources 21 of the markers M1, M2, M3, M4 or by their self-luminosity or by the ambient light 25 so that they can still be recognized in the dark. The flat marker Mf can also be provided with a self-illuminating coating 27 or a reflective coating 26 in order to be better recognizable even in the dark or to be able to reflect the radiation from the ambient light 25 with high intensity to the respective camera 4. In addition, the area markings Mf can be used to identify the object O with the markers M1, M2, M3, M4, for example the trailer 3, over a greater distance of up to 10m if the markers M1, M2, M3, M4 cannot be sufficiently resolved by the camera 4 under certain circumstances. Thus, at the beginning, a coarse identification based on the area markings Mf and, depending on this, a targeted approach of the camera 4 to the respective object O can take place until the camera 4 can also adequately resolve the markers M1, M2, M3, M4. The object plane OE can then be determined using only the markers M1, M2, M3, M4 or using the markers M1, M2, M3, M4 and the area markings Mf, so that redundant information can be used for the determination can.

The area markings Mf can also provide additional information that can contribute to determining the position of the object plane OE in space. For example, the area markings Mf can be positioned adjacent to the edges 17 of the front side 3a of the trailer 3 or of the respective object O. As a result, not only the object plane OE itself can be determined, but also the extent of the respective object O or the object area OF which the respective object O occupies within the determined object plane OE. An object width OB and an object flea OFI of the front side 3a or of the respective object O within the determined object plane OE can therefore be estimated if it is assumed that the markers M1, M2, M3, M4 or at least some of the Markers M1, M2, M3, M4 delimit the object O on the edge.

The markers M1, M2, M3, M4 themselves or at least some of the markers M1, M2, M3, M4 can also be arranged in this way on the edges 17, so that their marker positions P1, P2, P3, P4 or marker vectors V1, V2, V3, V4, the object width OB and the object fleas OFI of the object O within the determined object plane OE can be estimated. If more than four markers M1, M2, M3, M4 and / or area markings Mf are provided, these can also delimit a polygonal object area OF in the object plane OE, so that a shape or a contour K of the object O within the determined object plane OE can be extracted. In addition, conclusions can be drawn about the shape of the entire object O, for example in the case of a trailer 3.

The object width OB and / or the object height OFI can thus be determined or at least estimated on the basis of different reference points. In the case of a trailer 3 the corresponding extension of the front side and in the case of a loading ramp 11a or a garage door 11b its areal extension. If it is unknown whether the respective reference points (markers, area markings, etc.) are on the edge, at least an approximate (minimal) limitation of the respective object O and thus an approximate (minimal) object width OB and / or can be derived from this Approximate (minimal) object fleas OFI can be estimated.

In addition, the area markings Mf can have QR codes CQ or barcodes CB or Aruco markers CA (see FIG. 5a). In these, the object width OB and / or the object fleas OFI of the object O in particular special within the determined object plane OE and / or the marker vectors V1, V2, V3, V4 and / or the marker positions P1, P2 , P3, P4 relative to the first reference point BP1 (for example, the first coupling point 6 on trailer 3) be coded. For example, the control unit 5, which is connected to the camera 4, can determine the first coordinate system K1 or extract the corresponding information from the transformation matrix T even without previously reading in this data. The QR codes CQ or barcodes CB or Aruco marker CA can be created after calibration of the markers M1, M2, M3, M4 and as part of the Area markings Mf are then applied close to the area on the respective object O marker.

It can also be provided that geometric information of the object O, for example the object width OB and / or the object height OH of the object O, in particular within the determined object plane OE, and / or the marker vectors V1, V2, V3, V4 and / or the marker positions P1, P2, P3, P4 relative to the first reference point BP1 (for example the first coupling point 6 on the trailer 3) via the marker positions P1, P2, P3, P4 on the respective object O. are. Thus, from the spatial arrangement of the markers M1, M2, M3, M4 it can be recognized where, for example, the first reference point BP1, e.g. the first coupling point 6, is located. With four markers M1, M2, M3, M4, for example, one marker each can be arranged at the top left, top center and top right and another marker at the bottom center. This spatial arrangement is then assigned to a certain fixed position of the first Ankup pelpunktes 6, which the control unit 5 is known. Correspondingly, in the case of a different fixed position of the first coupling point 6, a different spatial arrangement of the markers M1, M2, M3, M4 can be assigned, it also being possible for further markers to be provided for further subdivision.

In principle, the QR codes CQ or barcodes CB or aruco marker CA with the corresponding coding can also be applied in a correspondingly curved manner on the markers M1, M2, M3, M4 (not shown), so that the respective data for defining the first Coordinate system K1 or to identify the marker positions P1, P2, P3, P4 of the markers M1, M2, M3, M4 can be recognized by the camera 4. Furthermore, communication units 30 can also be arranged in one or more markers M1, M2, M3, M4 (see FIG. 5a) which are designed to contain these data (the object width OB and / or the object height OH of the object O, in particular within the determined object plane OE, and / or the marker Vectors V1, V2, V3, V4 and / or the marker positions P1, P2, P3, P4 rela tively to the first reference point BP1) wirelessly, for example via Bluetooth 30a, RFID 30b, or the like, to the towing vehicle 2 or to transmit the control unit 5, for example a trailer identifier ID.

With the markers M1, M2, M3, M4 designed in this way, a number of assistance functions Fi can be carried out depending on the vehicle type:

As already described, in the case of a multi-part vehicle 1 comprising a towing vehicle 2 and a trailer 3, the articulation angle KW between these can preferably be determined continuously with the aid of the markers M1, M2, M3, M4. This articulation angle KW can then be used, for example, to control the multi-part vehicle 1 when reversing and / or during a parking process or to estimate the stability during cornering by means of a change in the articulation angle dKW. An assistance function F1 based on the articulation angle can thus be provided.

Furthermore, a coupling assistance function F2 can be made possible with the aid of the normal distance AN or the reference distance AR. Coupling points 6, 7, for example, can be selected as reference points PR1, PR2, with a lateral reference distance ARI and a vertical reference distance ARv being determined from the resulting reference distance AR. These also follow from the pose PO of the object plane OE, determined via the transformation matrix T, relative to the image sensor 4a or the object plane OE in the second coordinate system K2. This enables a targeted approach of the second coupling point 7 on the towing vehicle 2 to the first coupling point 6 on the trailer 3 when the towing vehicle 2 is controlled manually or automatically as a function of the components of the reference distance ARI, ARv. Alternatively or additionally, depending on the determined relative position of the object plane OE or the front side 3a of the trailer 3, trailer information AI can also be created and displayed by a display device 8 together with the recorded image B of the camera 4 for the driver to see. For example, a trailer identifier ID, the normal distance AN and / or the reference distance AR, the articulation angle KW, etc. can be displayed by the display device 8 as trailer information AI. The display device 8 can superimpose the trailer information AI on the image B recorded by the respective camera 4, so that both the image of the surroundings U and the trailer information Ai are displayed. The trailer information AI can for example be clearly scaled as a function of the distance AN, AR and displayed superimposed in the image area of the image B in which the front side 3a of the trailer 3 is shown.

Furthermore, it can be provided that the display device 8 displays the contour K, for example of the front side 3a of the trailer 3 or of the entire trailer 3, as trailer information AI. The contour K is modeled from the object plane OE determined via the markers M1, M2, M3, M4 as a function of the stored or determined object width OB and object height OH of the trailer 3 in each case. The marker positions P1, P2, P3, P4 of the markers M1, M2, M3, M4 can also be taken into account if they are arranged, for example, on the edges 17 of the front side 3a. The trailer contour K can be displayed individually or superimposed on the image B. This can, for example, simplify maneuvering or coupling in the dark.

Furthermore, the first or second coupling point 6, ie the kingpin 6a or the satellite coupling 7a, can be displayed individually or as an overlay over the image B by the display device 8 as trailer information AI. Since, for example, the kingpin 6a in image B of camera 4 is not directly can be seen, coupling can be facilitated by this superimposition, possibly in combination with the displayed reference distance AR, or a coupling process can be precisely monitored, for example, even in the dark.

In addition, a trailer center axis 40 of the trailer 3 and a towing vehicle center axis 41 of the towing vehicle 2 can be superimposed on the image B from the display device 8 as trailer information AI. While the central axis of the towing vehicle 41 is known, the central axis of the trailer 40 can be determined from the object level OE determined via the markers M1, M2, M3, M4 as a function of the stored or determined object width OB and / or object height OH Trailer 3 can be modeled. The marker positions P1, P2, P3, P4 of the markers M1, M2, M3, M4 can also be taken into account if they are arranged, for example, on the edges 17 of the front side 3a. The angle between the trailer center axis 40 of the trailer 3 and a towing vehicle center axis 41 of the towing vehicle 2 is then the articulation angle KW, which can also be displayed. The display or superimposition of the center axes 40, 41 enables the driver to position both lines relative to one another, e.g. to bring them one on top of the other, so that he can be supported during a coupling process, for example. An axis that is parallel to the trailer center axis 40 of the trailer 3 or the towing vehicle center axis 41 of the towing vehicle 2 can also be drawn in each case with the same effect.

In addition, control information Sl can be superimposed on the image B from the display device 8, which shows the driver, for example by arrows, in which direction he has to steer the towing vehicle 2 in order to approach the second coupling point 6 to the first coupling point 7. The control information Sl can, for example, by a Speaking control algorithm can be determined on the control unit 5, which determines a suitable trajectory.

Furthermore, a cargo hold camera 10 can be provided in the cargo hold 10a of the trailer 3, which camera can detect a loaded cargo. The cargo space images LB recorded by the cargo space camera 10 can be displayed by the display device 8. The cargo space images LB can be placed over the images B of the camera 4 in such a way that they are displayed in the area of the trailer 3, which is verified by the markers M1, M2, M3, M4. As a result, the driver can also check the freight during operation or recognize what the trailer 3 detected by the camera 4 has loaded. This can be done when approaching or while driving past the trailer 3, e.g. at a depot 11a, in order to visually verify whether a trailer 3 is assigned to the towing vehicle 2.

In addition to an internal application in a multi-part vehicle 1 as described, it can be provided as part of a distance assistance function F3 that the markers M1, M2, M3, M4, for example, on a building 11, e.g. a loading ramp 11 a, a garage door 11 b, etc., or are positioned on a moving or stationary third-party vehicle 12 or on other obstacles in the environment U, which can each be recognized by the camera 4 as potentially relevant objects O.

The markers M1, M2, M3, M4 can thus also be used in the manner described to determine a relevant object plane OE of these objects O when the marker positions P1, P2, P3, P4 and / or the marker vectors V1 , V2, V3, V4 are known. These can then also be combined with area markings Mf and / or light sources 21 and / or a self-illuminating coating 27 and / or reflective coating 26 in the described manner in order to conditions to enable the object level OE to be determined as reliably and simply as possible.

List of reference symbols (part of the description)

1 vehicle

2 towing vehicle

3 trailers

3a front of the trailer 3

4 camera

42 Towing vehicle camera

43 Trailer camera 4a image sensor

5 control unit

6 first coupling point

6a kingpin

7 second coupling point

7a fifth wheel

8 Display device

10 cargo space camera

11 buildings

11 a loading ramp

11 b garage door

12 Third-party vehicle

17 edges of the object O

20 marker interior

21 light source

21 a clearance lights

22 Light control

23 Energy source

23a solar panel 24 motion sensor

25 Ambient light

26 reflective coating 27 self-luminous coating 27a fluorescent coating 30 communication unit 30a Bluetooth 30b RFID

40 trailer center axle

41 Towing vehicle center axis AN Normal distance AR Reference distance ARI Lateral reference distance ARv Vertical reference distance B Fig

BE image plane

BPi pixels

C color

CQ QR code

CB barcode

CA Aruco marker

DP pivot point dt pulse duration dKW change in articulation angle

E detection area

E2 towing vehicle detection area

E3 Trailer detection area f focal length

F1 assistance function based on the articulation angle

F2 coupling assistance function

F3 distance assistance function ID Tag identifier

K contour of the object O

K1 first coordinate system (marker-fixed)

K2 second coordinate system (camera fixed)

KB image coordinate system

KD camera data

KW articulation angle

LB cargo space picture

M1, M2, M3, M4 markers

M1a, M2a M3a, M4a marker mapping

Mf area marking

O object

OB object width

OE object level

OF object area

OFI object fleas

P1, P2, P3, P4 marker position

PB1 first reference point

PB2 second reference point

PO pose

PPi object point

PR1 first reference point

PR2 second reference point

Sl control information

SL beacon

SV aspect ratio of the image sensor 4a

T ransformationsmatrix u environment

U1 first origin

U2 second origin

V1, V2, V3, V4 marker vector z state of motion xB, yB image coordinates x1, y1, z1 first coordinates in the first coordinate system K1 x2, y2, z2 second coordinates in the second coordinate system K2

Claims

1. A method for determining a pose (PO) of an object (O) relative to a vehicle (1), the object (O) and the vehicle (1) being movable relative to one another and the object (O) being able to move at least three markers (M1 , M2, M3, M4), the object (O) being detected by at least one camera (4) on the vehicle (1), with at least the following steps:

- Detecting the at least three markers (M1, M2, M3, M4) with the camera (4) and generating an image (B), the at least three markers (M1, M2, M3, M4) in the image (B) respectively a marker image (M1 a, M2a, M3a, M4a) is assigned;

- Determination of marker positions (P1, P2, P3, P4) and / or marker vectors (V1, V2, V3, V4) of the markers (M1, M2, M3, M4) on the detected object (O);

- Determination of a transformation matrix (T) depending on the marker positions (P1, P2, P3, P4) and / or the marker vectors (V1, V2, V3, V4) as well as depending on the marker images (M1a, M2a, M3a, M4a), where the transformation matrix (T) places the markers (M1, M2, M3, M4) on the object (O) on the marker mapping (M1a, M2a, M3a, M4a) in the image (B) of the camera (4) depicted on the vehicle (1); and

- Determination of an object plane (OE) formed by the markers (M1, M2, M3, M4) on the object (O) in a second coordinate system (K2) as a function of the determined transformation matrix (T), the second coordinate system (K2) being fixed to the vehicle is for determining the pose (PO) of the object (O) relative to the vehicle (1), characterized in that the at least three markers (M1, M2, M3, M4) on the object (O) are spatially extended and in flat marker images (M1a, M2a, M3a, M4a) are assigned to the image (B).

2. The method according to claim 1, characterized in that the camera (4) at least three markers (M1, M2, M3, M4), preferably at least four markers (M1, M2, M3, M4) are detected that are spherical or are cylindrical or cuboid.

3. The method according to any one of the preceding claims, characterized in that at least one of the at least three markers (M1,

M2, M3, M4)

- Is illuminated from the inside and / or behind, for example via a light source (21) and / or arranged in a marker interior (20) of the at least three markers (M1, M2, M3, M4)

- Is illuminated and / or irradiated from the outside, for example via an ambient light (25), preferably on the vehicle (1), and / or

- Has a self-luminous coating (27), for example a fluorescent coating (27a).

4. The method according to claim 3, characterized in that the light source (21) and / or the ambient light (25) is controlled as a function of a movement state (Z) of the vehicle (1) and / or the object (O).

5. The method according to claim 3 or 4, characterized in that

- A color (C) of the light source (21) and / or the ambient light (25) and / or a pulse duration (dt) of the light source (21) and / or the ambient light (25) as a function of a distance (AN, AR) between between the vehicle (1) and the object (O), and / or

- A color (C) of the light source (21) and / or a pulse duration (dt) of the light source (21) is set as a function of the marker position (P1, P2, P3, P4) on the object (O), and / or

- A color (C) of the self-luminous coating (27) on at least one of the at least three markers (M1, M2, M3, M4) as a function of the Marker position (P1, P2, P3, P4) is set on the object (O).

6. The method according to any one of claims 3 to 5, characterized in that the light sources (21) in at least one of the at least three markers (M1, M2, M3, M4) from an energy source (23), for example a solar panel (23a), are supplied with energy at the object (O).

7. The method according to any one of claims 3 to 6, characterized in that at least one of the at least three markers (M1, M2, M3, M4) is gebil det by a clearance light (21a) on the edges (17) of the object (O).

8. The method according to any one of claims 3 to 7, characterized in that the ambient light (25) emits visible and / or invisible radiation onto the markers (M1, M2, M3, M4) and the markers (M1, M2, M3 , M4) have a reflective coating (26).

9. The method according to any one of the preceding claims, characterized in that the object (O) has an object width (OB) and an object height (OH).

10. The method according to claim 9, characterized in that on at least one of the markers (M1, M2, M3, M4) or adjacent to at least one of the markers (M1, M2, M3, M4) a QR code (CQ) and / or a barcode (CB) and / or an aruco marker (CA) is applied to the surface and the QR code (CQ) and / or the barcode (CB) and / or the aruco marker (CA) from the camera (4) is recorded.

11. The method according to claim 10, characterized in that from the QR code (CQ) and / or the barcode (CB) and / or the Aruco marker (CA) detected by the camera (4) the object width (OB ) of the ob- project (O) and / or the object height (OH) of the object (O) and / or the marker positions (P1, P2, P3, P4) and / or the object vectors (V1, V2, V3, V4 ) be determined.

12. The method according to any one of claims 9 to 11, characterized in that the object width (OB) of the object (O) and / or the object height (OH) of the object (O) and / or a first reference point (BP1 ) on the object (O) depending on the spatial arrangement of the recognized markers (M1, M2, M3, M4) on the object (O) to one another and / or at least be estimated.

13. The method according to any one of claims 9 to 12, characterized in that the object width (OB) of the object (O) and / or the object height (OH) of the object (O) and / or a first reference point (BP1 ) on the object (O) and / or the marker positions (P1, P2, P3, P4) and / or the marker vectors (V1, V2, V3, V4) via a communication unit (30) on the object (O) , for example via Bluetooth (30a) or RFID (30b) to the vehicle (1).

14. The method according to any one of claims 9 to 13, characterized in that the camera (4) additionally captures area markings (Mf) which are adjacent to at least one of the markers (M1, M2, M3, M4) on the object (O) are arranged, with a redundant determination of the pose (PO) of the object (O) relative to the vehicle (1) takes place from the detected area markings (Mf).

15. The method according to claim 14, characterized in that the area markings (Mf) and / or the markers (M1, M2, M3, M4) are at least partially arranged on the edges (17) of the object (O) and are made of the object width (OB) of the object (O) and / or the object height (OH) of the object (O) derived from the captured image (B) of the camera (4) will.

16. The method according to any one of the preceding claims, characterized in that

- The vehicle (1) is in one piece and the object (O) is not connected to the vehicle (1), the vehicle (1) moving relative to the object (O) and the object (O) a trailer to be coupled (3) or a building (11), for example a loading ramp (11 a) or a garage door (11 b), or a third-party vehicle (12), or that

- The vehicle (1) is in several parts and the camera (4; 42; 43) is arranged on a towing vehicle (2) and / or on a trailer (3) coupled to it, wherein

- The object (O) is connected to the multi-part vehicle (1), the object (O) being a coupled trailer (3) which moves at least temporarily relative to the towing vehicle (2), or

- The object (O) is not connected to the multi-part vehicle (1), the object (O) being a building (11), for example a loading ramp (11 a) or a garage door (11 b), or a third-party vehicle ( 12) is.

17. The method according to any one of the preceding claims, characterized in that the image (B) of the camera (4) is displayed on a display device (8), the image (B) being a normal distance from the display device (8) (AN) and / or a reference distance (AR) and / or a contour (K) of the object (O) and / or control information (Sl) and / or an articulation angle (KW) between the towing vehicle (2) and the trailer (3) and / or a first coupling point (6) and / or a second coupling point (7) and / or a trailer identifier (ID) and / or a cargo space image (LB) and / or one depending on the marker (M1, M2, M3, M4) determined trailer center axis (40) and / or a towing vehicle center axis (41) are superimposed.

18. A method for controlling a vehicle (1) as a function of a pose (PO) of an object (O) relative to the vehicle (1), the pose (PO) of the object (O) being determined in a method according to one of the preceding claims the vehicle (1)

- Within the framework of an assistance function (F1) based on the articulation angle, depending on the articulation angle (KW) derived from the determined pose (PO) of the object (O) between a towing vehicle (2) and a trailer (3) of a multi-part vehicle (1) and / or a Knickwin angle change (dKW) is controlled, or

- As part of a coupling assistance function (F2) depending on a normal distance (AN) and / or reference distance (AR) between the towing vehicle (2) as a vehicle (1 ) and a trailer (3) to be coupled as an object (O) on which the at least three markers (M1, M2, M3, M4) are arranged, is controlled in such a way that a first coupling point (6) is located on the trailer to be coupled ( 3) approaches a second coupling point (7) on the towing vehicle (2) and the two coupling points (6, 7) are coupled to one another at a common pivot point (DP), or

- As part of a distance assistance function (F3) as a function of a normal distance (AN) and / or reference distance (AR) between the towing vehicle (2) derived from the determined pose (PO) of the object (O) Vehicle (1) and a building (11) as an object (O) on which the at least three markers (M1, M2, M3, M4) are arranged, for example a loading ramp (11a) or a garage door

(11 b), or a foreign vehicle (12) as an object (O) on which the min least three markers (M1, M2, M3, M4) are arranged, is controlled.

19. Control unit (5) for performing a method according to one of the preceding claims.

20. Vehicle (1) with a control unit (5) according to claim 19, wherein the vehicle (1) is one-piece or multi-part and the at least one camera (4) on the towing vehicle (2) and / or the trailer (3) of the multi-part vehicle (1) is arranged.

21. The vehicle (1) according to claim 20, characterized in that the min least three markers (M1, M2, M3, M4) are arranged on a front side (3a) of the trailer (3).