Positioning system

Abstract

Position determination system with a 3D-TOF camera (200) arranged on a vehicle and an active lighting system (100) associated with the 3D-TOF camera, wherein an evaluation unit associated with the 3D-TOF camera (200) is designed such that, starting from a detected detection marker (400, 401, 402) with a known position and a second detected known position (401, 402, 490), in particular the starting position (490) of the vehicle and / or a second detection marker (401, 402), a position and an orientation of the vehicle in a reference system is determined, wherein the 3D-TOF camera (200) additionally observes a spatial scene around the vehicle, and is designed such that a safety-relevant reaction is initiated when an obstacle is detected.

Description

[0001] The invention relates to a position determination system with a 3D-TOF camera and associated active lighting, as well as a method for position determination according to the preamble of the independent claims.

[0002] From DE 297 24 884 U1, an agricultural vehicle is known that uses data from a satellite navigation receiver to align a processing attachment adjustable to the vehicle. To determine the position and orientation of the processing attachment, receiving antennas of the satellite receiver are arranged at reference points on the attachment. To improve the accuracy of the positioning, a second terrestrial GPS signal is generated using a base station in addition to the satellite GPS signal. The position of the stationary base station is known, so that the satellite navigation receiver can determine the position of the processing attachment in the terrestrial reference system very accurately from the difference between the two GPS signals.

[0003] Systems for three-dimensional image acquisition that utilize active illumination are also known from the prior art. These include so-called time-of-flight (TOF) or transit-time measurement systems. These systems use amplitude-modulated or pulsed illumination to illuminate the three-dimensional scene to be captured.

[0004] The term "light time-of-flight measurement system" is intended to include, in particular, all 3D-TOF camera systems that derive time-of-flight information from the phase shift of emitted and received radiation. Photomixing detectors (PMDs), such as those described in patent applications DE 196 35 932, EP 1 777 747, US 6 587 186, and DE 197 04 496, and available, for example, from ifm electronic gmbh as the Frame Grabber O3D101 / M01594, are particularly suitable as 3D-TOF cameras or PMD cameras. The PMD camera allows, in particular, a flexible arrangement of the light source and the detector, which can be housed in a single unit or mounted separately.

[0005] The object of the invention is to further develop a 3D-TOF camera system for position determination.

[0006] The problem is advantageously solved by the device and method according to the invention as defined in the independent claims.

[0007] Advantageously, a positioning system is provided with a 3D time-of-flight (TOF) camera mounted on a vehicle and associated active lighting. In this system, an evaluation unit associated with the 3D TOF camera is designed such that, starting from a detected marker with a known position and a second detected known position, in particular the vehicle's starting position and / or a second detection marker, the vehicle's position and orientation in a reference system are determined. This approach has the particular advantage that a 3D TOF camera already mounted on the vehicle for spatial monitoring can also be used to determine the position and orientation of the vehicle or a harvesting machine.

[0008] The detection markers are advantageously equipped with a reflector or designed as a reflector in their entirety. Designing the detection marker with a reflector has the particular advantage that the light from the active illumination is intensely reflected back towards the 3D-TOF camera, thus enabling the detection marker to be distinguished from the rest of the scene with a high degree of certainty.

[0009] Conveniently, defined optical properties are assigned to different detection markers, so that each individual detection marker can be clearly distinguished from other detection markers.

[0010] Advantageously, each optical property in the system has a corresponding code, allowing a suitably designed evaluation unit to determine the underlying code based on the detected optical properties of the detection marker. The code can, for example, include the exact position of the detection marker.

[0011] Furthermore, it is advantageous if the evaluation unit for determining the vehicle's position and orientation also takes into account the vehicle's current spatial orientation or movement. The vehicle's orientation or movements can be determined, if necessary, using additional sensors on the vehicle.

[0012] In a further embodiment, the 3D-TOF camera is movably mounted on the vehicle, so that even during operation or when the vehicle is moved, at least one detection marker advantageously remains within the 3D-TOF camera's field of view. This approach ensures that the vehicle's position, orientation, and movement can be determined even after an initial position and / or orientation determination.

[0013] Furthermore, a method for determining the position of a positioning system of the aforementioned type is advantageously provided, in which, based on a detected detection marker with a known position and a second detected position, in particular the starting position of the vehicle and / or a second detection marker, a position and an orientation of the vehicle in a reference system are determined.

[0014] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings.

[0015] They show:

[0016] Fig. 1. Schematically, the basic principle of photomixed detection,

[0017] Fig. 2 schematically a working machine in a field area with detection markers,

[0018] Fig. 3 schematically the principle of the position determination according to the invention,

[0019] Fig. 4. Position determination within enclosed spaces,

[0020] Fig. 5 different design options for detection markers.

[0021] Fig. Figure 1 shows a measurement situation for an optical distance measurement with a 3D-TOF camera system, as is known, for example, from DE 197 04 496.

[0022] The 3D-TOF camera system includes a transmitter unit or a lighting module. 100 with a light source 12 and an associated beam shaping optics 50 as well as a receiver unit or 3D-TOF camera 200 with a receiving optic 150 and a photo sensor 15 The photosensor 15 is preferably configured as a pixel array, in particular as a PMD sensor. The receiving optics typically consist of several optical elements to improve the imaging properties. The beam shaping optics 50 the transmitting unit 100It is preferably designed as a reflector. However, diffractive elements or combinations of reflective and diffractive elements can also be used.

[0023] The measuring principle of this arrangement is essentially based on the fact that, starting from the phase difference of the emitted and received light, the travel time of the emitted and reflected light can be determined. For this purpose, the light source and the photosensor are used. 15 via a modulator 18 Together with a specific modulation frequency, it is subjected to a first phase angle 'a'. The light source emits a signal corresponding to the modulation frequency. 12 An amplitude-modulated signal with phase a is emitted. In the illustrated case, this signal, or electromagnetic radiation, is emitted by an object. 20reflected and, due to the distance traveled, hits the photosensor with a second phase shift b. 15 In the photosensor 15 The signal of the first phase position a of the modulator will be 18 The received signal, which has now assumed a second phase position b, is mixed, and the phase shift or object distance is determined from the resulting signal.

[0024] Fig. Figure 2 schematically shows an agricultural work machine 500 in a starting position 490 in a field area 450 The corners of the rectangular field area 450 are equipped with detection markers 400 marked. The work machine 500 In the illustrated case, it is aligned such that the detection range E of the 3D-TOF camera 200 two detection markers 400The invention provides for the positioning markers to be arranged at precisely defined geographical positions outside the field to be processed. Preferably, the detection markers have different optical properties by which a specific detection marker can be uniquely identified. Such coding is possible, for example, via size, geometry, reflectivity, backscatter function, polarization, etc. Advantageously, at least a portion of the detection marker is designed as a reflector.

[0025] Fig. Figure 3 shows the basic principle of the position determination according to the invention. As already mentioned in Fig. Shown in section 2, the work machine is located at a starting point. 490 The 3D TOF camera mounted on the vehicle 200 detects a first and second detection mark 401 , 402 with a known geographical position. The 3D-TOF camera 200 is on the vehicle 500The camera is mounted in a defined position so that the angular relationships captured by the 3D TOF camera can be unambiguously linked to the vehicle's reference system. The 3D TOF camera then allows the distance and angle of the detection markers to be determined relative to the vehicle's reference system and transferred to the reference system of the detection markers, thus enabling the determination of the vehicle's position and orientation. 500 can be determined in the reference system of the detection marks.

[0026] The first detection mark 401 is based on the vehicle's reference system or the 3D TOF camera 200 detected at an angle W01 and a distance D01 and the second detection marker 402at an angle W02 and a distance D02. The vehicle's position can be uniquely determined from the known detection mark spacing D12 and the two distances to the detection marks. By adding just one angle, the position relative to the detection marks' reference frame can also be determined. Knowing a second angle allows for a more precise determination of both the position and the orientation of the machine. Accuracy can be further improved if the vehicle is moved to a starting position at the beginning of a work operation, the geographical or terrestrial position of which is uniquely known. Such a starting position could, for example, be a corner of the field to be worked, into which the machine is positioned at the start of the operation.Once this starting position is reached, the driver could, for example, use a button to inform the positioning system that this starting position has been reached and initiate a corresponding calibration of the system.

[0027] Based on these initially precisely calibrated positions, the remaining positions in the field can be approached exactly during subsequent operations. Furthermore, it is advantageous to record additional, potentially redundant data during operation to increase the accuracy and reliability of position determination, such as the distance traveled or the vehicle's orientation in the longitudinal, lateral, and / or vertical axes of the reference system.

[0028] In Fig. 4 is a comparable situation for a forklift truck 460The diagram shows a setup where the detection markers are arranged within an enclosed space, for example, on the walls of the room. The detection markers are preferably coded as in the aforementioned example, so that they can be uniquely assigned within their reference system. In the illustrated example, the detection range of the 3D-TOF camera is... 200 on two adjacent detection markers 400 directed so that, according to the already in Fig. The geometric considerations shown in the 3 diagrams determine the position and orientation of the industrial vehicle. 460 can be clearly determined.

[0029] In a further development, it is conceivable to arrange a larger number of detection markers, for example, in a storage area, ensuring that a defined detection marker is always present within the 3D-TOF camera's detection range. A work area designed in this way allows the location and spatial orientation of the equipment to be unambiguously determined at any given time. Based on this comprehensive spatial and positional information, it is readily possible to equip such a vehicle for autonomous or driverless operation within its work area.

[0030] In the Fig. Figure 5 illustrates various possible designs for detection markers. The example on the left shows a first detection marker. 401 with a single reflection field 410 shown. In the second version 402 There is a large reflective field at the top. 410and a smaller reflection field spaced below it 411 The arrangement is preferably chosen such that the radiation emitted by the 3D-TOF camera system is reflected back at the reflective surfaces and can be clearly and precisely detected by the 3D-TOF camera. Naturally, it is also possible to assign different optical properties to the different reflective markers. In the example shown on the right, it is proposed to use the detection markers without a support. The encoding can be implemented, for example, such that a first detection marker... 403 Full-surface reflection while a second detection mark 402 exhibits areas with different optical properties.

[0031] Furthermore, it is of course possible to observe the spatial scene with the 3D TOF camera system mounted on the vehicle and, for example, to provide further control options based on the recorded data. For instance, it is easily possible to detect obstacles in the vehicle's driving area with the help of this system and, if necessary, to react to them in a safety-relevant manner.

[0032] Furthermore, it is also possible to use the three-dimensional capture of the environment to detect the contours of a harvested crop swath and to provide appropriate support to the driver or even to control the vehicle autonomously.

[0033] Furthermore, it is advantageous to mount the 3D TOF camera on the vehicle in a movable position. This allows for determining the vehicle's position and orientation even if initially only one detection marker is captured within the 3D TOF camera's field of view. By moving the camera, the surroundings can be scanned for additional detection markers, and any further detected markers with known positions can be added to the system.

[0034] When using more than two detection markers, the 3D-TOF camera, preferably movable 360° around the vertical axis, allows all detection markers in the environment to be captured and taken into account when determining the position and orientation of the vehicle.

[0035] When the vehicle is moved, such an arrangement allows the detection range of the 3D-TOF camera to always be adjusted so that at least one detection marker is within the field of view of the 3D camera.

[0036] Of course, it is also advantageous to use multiple 3D TOF cameras, for example, to use one camera to preferably observe the surroundings in the direction of travel of the vehicle, while the second 3D TOF camera is preferably used for position determination. In principle, however, both or more 3D TOF cameras can also be used redundantly.

[0037] Furthermore, it is also conceivable to provide a three-dimensional all-round view through suitable optical systems or the use of several 3D-TOF cameras, without the need for any mechanical movement.

[0038] In addition to the one in Fig. 2 and Fig.In the situation shown in Figure 3, it is also conceivable to determine the location and position of the vehicle using only a detection marker and a well-known starting position. 490 To determine this, it must be ensured that the starting position can be assumed exactly. After transmitting the starting position to the positioning system and detecting a marker with a known position, the orientation and position of the vehicle can be unambiguously determined. QUOTES INCLUDED IN THE DESCRIPTION

[0039] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0040] DE 29724884 U1

[0002] DE 19635932

[0004] EP 1777747

[0004] US 6587186

[0004] DE 19704496 [0004, 0021]

Claims

[1] Position determination system with a 3D TOF camera mounted on a vehicle ( 200 ) and one of the active lighting systems assigned to the 3D-TOF camera ( 100 ), in which one of the 3D-TOF cameras ( 200 ) assigned evaluation unit is designed in such a way that, starting from a detected detection mark ( 400 , 401 , 402 ) with known position and a second recorded known position ( 401 , 402 , 490 ), especially the starting position ( 490 ) of the vehicle and / or a second detection mark ( 401 , 402 ), a position and orientation of the vehicle in a reference system is determined. [2] Position determination system according to claim 1, wherein the detection marker ( 400 ) with a reflector ( 410 , 411 ) provided or as a reflector ( 403 , 404 ) is trained. [3] Position determination system according to one of the preceding claims, wherein at least one detection mark ( 400 ) distinguishable or encoded by defined optical properties. [4] Position determination system according to one of the preceding claims, wherein the evaluation unit is designed such that the detected optical properties of the detection mark ( 400 ) a code can be determined. [5] Position determination system according to one of the preceding claims, wherein the evaluation unit additionally takes into account the spatial orientation or movement of the vehicle. [6] Position determination system according to one of the preceding claims, wherein the 3D-TOF camera ( 200 ) is movably arranged on the vehicle. [7] Position determination system according to one of the preceding claims, wherein the 3D-TOF camera ( 200) is tracked in such a way that, after a position and / or orientation determination of the vehicle, at least one detection marker ( 400 ) within the detection range of the 3D-TOF camera ( 200 ) lies. [8] Method for determining the position of a positioning system with a 3D TOF camera mounted on a vehicle ( 200 ) and one of the active lighting systems assigned to the 3D-TOF camera ( 100 ), in which, based on a detected marker ( 400 ) with a known position and a second recorded position ( 401 , 402 , 490 ), especially the starting position ( 490 ) of the vehicle and / or a second detection mark ( 401 , 402 ), a position and orientation of the vehicle in a reference system is determined.

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