Apparatus and method for calibrating a laser scanner

Abstract

The invention relates to a device for calibrating a laser scanner (3), in particular a laser scanner of a vehicle (2), comprising at least one reflecting unit (21, 22) for reflecting a laser beam (L) of the laser scanner (3), wherein the at least one reflecting unit (21, 22) comprises a first shield (7), a second shield (8) and a screen (5), wherein the first shield (7) is arranged between the second shield (8) and the screen (5) along an irradiation direction (S), wherein the first shield (7) has a first reflecting surface (31) extending at least approximately perpendicular to the irradiation direction (S), and the second shield (8) The invention relates to a screen (5) having a second reflecting surface (32) extending at least approximately perpendicular to the irradiation direction (S), and a screen (5) having a third reflecting surface (33) extending at least approximately perpendicular to the irradiation direction (S), wherein the first shield (7) is arranged offset relative to the second shield (8) in the vertical direction (Z) so that a gap (9) is formed between the first shield (7) and the second shield (8), the gap extending in the vertical direction (Z) and the transverse direction (Y), and wherein the screen (5) is constructed and arranged so that a projection of the gap (9) in the irradiation direction (S) falls completely on the third reflecting surface (33) of the screen (5). The present invention also relates to a method for calibrating a laser scanner (3), in particular a laser scanner of a vehicle (2), by means of a device according to the invention, wherein a laser beam (L) of the laser scanner (3) is directed at least approximately along an irradiation direction (S) toward at least one reflective unit (21, 22), and the laser beam (L) moves along at least one reflective unit (21, 22) in a transverse direction (Y), and for a plurality of positions of the laser beam (L) in the transverse direction (Y), a distance (D) of the laser scanner (3) from a reflective surface (31, 32, 33) from which the laser beam (L) is reflected is measured in each case, and the orientation of the laser scanner (3) is determined from the measured distances (D) of the laser scanner (3) from the respective reflective surfaces (31, 32, 33).

Description

Technical Field

[0001] The invention relates to a device for calibrating a laser scanner, in particular for calibrating a laser scanner of a vehicle, comprising at least one reflection unit for reflecting a laser beam of the laser scanner. The invention also relates to a method for calibrating a laser scanner. Background Art

[0002] Vehicles, particularly autonomous vehicles, such as self-propelled mobile transport systems, equipped with one or more laser scanners are known. Such mobile transport systems are used, for example, to transport objects within technical facilities. Technical facilities are particularly industrial applications, such as production halls. The laser scanner emits a laser beam, detects the reflected laser beam, and calculates the distance to the object that reflected the laser beam. Autonomous vehicles use laser scanners, in particular, to identify obstacles in technical facilities.

[0003] A vehicle's laser scanner should be oriented so that the laser beam emitted by it runs as parallel as possible to the ground surface on which the vehicle is located. This ensures that the laser beam is not reflected by the ground surface, but rather by objects in the surroundings, particularly obstacles. Such objects can then be used for vehicle positioning and navigation. Aligning the laser scanner so that the laser beam runs parallel to the ground, i.e., horizontally, is referred to as calibrating the laser scanner.

[0004] A method for calibrating a distance image sensor is known from DE 10 2004 033 114 A1, wherein a device having a calibration object with three calibration surfaces is used for this purpose.

[0005] DE 101 16278 A1 discloses a method for adjusting a distance sensor arranged on a vehicle. For this purpose, a device having three reference objects is used. Summary of the Invention

[0006] The object of the present invention is to provide a device and a method for calibrating a laser scanner.

[0007] This object is achieved by a device for calibrating a laser scanner.

[0008] The apparatus for calibrating a laser scanner, particularly a laser scanner for calibrating a vehicle, according to the present invention includes at least one reflective unit for reflecting a laser beam from the laser scanner. The at least one reflective unit includes a first shield, a second shield, and a screen, wherein the first shield is arranged between the second shield and the screen in the irradiation direction. The first shield has a first reflective surface extending at least approximately perpendicular to the irradiation direction, the second shield has a second reflective surface extending at least approximately perpendicular to the irradiation direction, and the screen has a third reflective surface extending at least approximately perpendicular to the irradiation direction. The first shield is arranged vertically offset relative to the second shield so that a gap is formed between the first and second shields, extending in both the vertical and lateral directions. The screen is constructed and arranged so that a projection of the gap in the irradiation direction falls entirely on the third reflective surface of the screen.

[0009] The vertical direction extends perpendicular to the illumination direction. The vertical direction also extends perpendicular to the transverse direction. The illumination direction also extends perpendicular to the transverse direction. The directional specifications used herein—the vertical direction, the transverse direction, and the illumination direction—are each defined relative to the reflector unit. Hereinafter, any direction extending perpendicular to the vertical direction is also referred to as the horizontal direction. The transverse direction and the illumination direction therefore refer to horizontal directions, while the vertical direction also extends perpendicular to the ground surface on which the reflector unit is located. Aligning the laser scanner so that its laser beam extends in the horizontal direction is referred to as calibrating the laser scanner.

[0010] During calibration, the laser scanner is held at a specified vertical distance from the ground surface, where at least one reflective element is located. The first and second shields are oriented so that the vertical distance between the gap and the ground surface is the same as the specified distance between the laser scanner's scanning plane and the ground surface. To calibrate the laser scanner, the laser beam of the laser scanner is directed at the at least one reflective element in an illumination direction and moved laterally along the at least one reflective element. The distance between the laser scanner and the reflective surface reflecting the laser beam is measured for each of the multiple positions of the laser beam in the lateral direction. When the laser beam reaches the gap, it is reflected by the third reflective surface of the screen. The laser beam of the laser scanner then extends horizontally along the at least one reflective element within an angular range.

[0011] The device according to the present invention is particularly useful for calibrating laser scanners on vehicles, particularly autonomous vehicles, such as self-propelled mobile transport systems. The laser scanner allows autonomous vehicles to detect obstacles. The device according to the present invention requires relatively little space and achieves relatively high accuracy when calibrating the laser scanner. Furthermore, the device according to the present invention is relatively inexpensive.

[0012] Preferably, the vertical extension of the third reflective surface of the screen is greater than the vertical extension of the gap, and the horizontal extension of the third reflective surface of the screen is greater than the horizontal extension of the gap. Therefore, a laser beam that reaches the gap at a slight angle relative to the irradiation direction will still fall on the third reflective surface of the screen.

[0013] According to a preferred design of the present invention, the device includes a first reflective unit and a second reflective unit, the first and second reflective units being oriented such that the illumination direction of the first reflective unit extends at least approximately perpendicular to the illumination direction of the second reflective unit. By displacing the two reflective units at least approximately perpendicularly with respect to each other, the laser scanner can be calibrated for different radiation angles of the laser beam and relative to two orthogonal horizontal axes. When the laser beam reaches the gap between the two reflective units, it is reflected by the third reflective surface of the screens of the two reflective units. The laser beam of the laser scanner then extends horizontally over an angle greater than 90°.

[0014] Preferably, the first reflector unit and the second reflector unit are oriented such that the radiation direction of the first reflector unit extends at least approximately parallel to the transverse direction of the second reflector unit. By displacing the two reflector units at least approximately perpendicularly relative to one another, the laser scanner can be calibrated for different radiation angles of the laser beam of the laser scanner and relative to two orthogonal horizontal axes.

[0015] Further preferably, the first reflective unit and the second reflective unit are oriented such that the vertical direction of the first reflective unit extends parallel to the vertical direction of the second reflective unit. This arrangement of the two reflective units relative to each other allows the laser scanner to be calibrated for different radiation angles of its laser beam and relative to two orthogonal horizontal axes.

[0016] Advantageously, the first reflective unit and the second reflective unit are oriented such that the gaps of the first reflective unit and the gaps of the second reflective unit are aligned with each other in the vertical direction. If the two reflective units are located on a common ground surface, the gaps of the reflective units are therefore spaced the same distance from the ground surface, and the laser beam of the laser scanner reaches both gaps of the two reflective units.

[0017] According to an advantageous embodiment of the present invention, at least one reflector unit includes at least one spacer arranged such that the first shield and the screen are offset relative to each other by a first distance in the illumination direction. This allows for greater precision in calibrating the laser scanner. Furthermore, the at least one spacer can serve to mechanically secure the screen.

[0018] According to an advantageous embodiment of the present invention, at least one reflector unit includes at least one base extending primarily in a vertical direction and arranged such that the first shield and the second shield are offset relative to each other by a second distance in the illumination direction. This allows for higher precision calibration of the laser scanner. Furthermore, the at least one base serves to mechanically secure the shield.

[0019] According to an advantageous embodiment of the present invention, at least one reflector unit includes at least one partition disposed transversely to the second shield and / or the first shield. The at least one partition has at least two reflective surfaces arranged at an angle relative to one another. Laser beams of the laser scanner that laterally reach the first or second shield in the transverse direction can also be reflected by the partition. The mutually inclined reflective surfaces are at different distances from the laser scanner and simplify the identification of the at least one reflector unit for the laser beam.

[0020] According to an advantageous embodiment of the present invention, the first reflective surface of the first shield and / or the second reflective surface of the second shield include a first reflective area and a second reflective area, wherein these reflective areas have different reflective properties, in particular, different colors and / or different surface materials. It has been shown that the different reflective properties of the reflective areas can simulate different distances from the laser scanner. Thus, the reflective areas with different reflective properties simulate different distances from the laser scanner and simplify the detection of the reflective surface.

[0021] According to an advantageous embodiment of the invention, the first reflective surface 31 of the first shield and / or the first reflective region of the second reflective surface of the second shield are covered with black foam.

[0022] According to an advantageous embodiment of the invention, at least the edges of the first shielding and / or the edges of the second shielding that are adjacent to the gap of the reflector unit are covered with black foam.

[0023] According to the method according to the present invention for calibrating a laser scanner, in particular a laser scanner for a vehicle, using the device according to the present invention, a laser beam of the laser scanner is directed at least approximately along an illumination direction toward at least one reflective element, and the laser beam is moved in a transverse direction along the at least one reflective element. The distance between the laser scanner and a reflective surface reflecting the laser beam is measured for each of a plurality of positions of the laser beam in the transverse direction.

[0024] When the laser beam reaches the first screen, it is reflected by the first reflective surface of the first screen. When the laser beam reaches the second screen, it is reflected by the second reflective surface of the second screen. When the laser beam reaches the gap, it is reflected by the third reflective surface of the screen. When the laser beam reaches the base of the reflective unit, it is reflected by the base of the reflective unit.

[0025] During calibration, the laser scanner is positioned at a defined vertical distance from the ground surface on which the at least one reflector unit is located. The first and second shields are oriented so that the gap, and in particular the center of the gap, is at the same defined vertical distance from the ground surface. During calibration, the laser scanner is also positioned at a defined distance from the reflector unit in the illumination direction.

[0026] Here, the distance of the laser scanner from the reflective unit in the irradiation direction is significantly greater than the extent of the reflective unit in the transverse direction. Consequently, the distance of the laser scanner from the center region of the reflective surface is only slightly less than the distance of the laser scanner from the edge region of the reflective surface. Consequently, the distance of the laser scanner from the reflective surface of the reflective unit in the irradiation direction can be considered approximately constant. This approximation is not accurate enough if the distance of the laser scanner from the reflective unit in the irradiation direction is of a similar order of magnitude to the extent of the reflective unit in the transverse direction. In this case, it is appropriate to convert the polar coordinates provided by the laser scanner (i.e., the radiation angle and the distance) into Cartesian coordinates (i.e., the position in the transverse direction and the distance in the irradiation direction).

[0027] The distance between the laser scanner and the second reflective surface is less than the distance between the laser scanner and the base. The distance between the laser scanner and the base is less than the distance between the laser scanner and the first reflective surface. The distance between the laser scanner and the first reflective surface is less than the distance between the laser scanner and the third reflective surface. The respective distances between the laser scanner and each reflective surface are known.

[0028] The orientation of the laser scanner is determined from the measured distances between the laser scanner and the corresponding reflective surfaces. When the laser beam is reflected by the first reflective surface of the first screen, the laser scanner is tilted vertically upward, i.e., away from the ground. When the laser beam is reflected by the second reflective surface of the second screen, the laser scanner is tilted vertically downward, i.e., toward the ground. When the laser beam is reflected by the third reflective surface of the screen, the laser beam extends horizontally, and the laser scanner is oriented horizontally.

[0029] In particular, the method according to the present invention allows for the calibration of a laser scanner on a vehicle, particularly an autonomous vehicle, such as a self-propelled mobile transport system. The laser scanner enables the autonomous vehicle to detect obstacles, among other things. The method according to the present invention enables relatively high accuracy and requires relatively little time when calibrating the laser scanner.

[0030] According to a preferred design solution of the present invention, the device includes a first reflecting unit and a second reflecting unit, and the first reflecting unit and the second reflecting unit are arranged so that the irradiation direction of the first reflecting unit extends at least approximately perpendicular to the irradiation direction of the second reflecting unit. Here, the laser beam of the laser scanner is aligned with the first reflecting unit at least approximately along the irradiation direction of the first reflecting unit, and the laser beam moves along the first reflecting unit in a lateral direction of the first reflecting unit. Here, for multiple positions of the laser beam in the lateral direction, the distance between the laser scanner and the reflective surface of the first reflecting unit that reflects the laser beam is measured respectively. The laser beam of the laser scanner is also aligned with the second reflecting unit at least approximately along the irradiation direction of the second reflecting unit, and the laser beam moves along the second reflecting unit in a lateral direction of the second reflecting unit. Here, for multiple positions of the laser beam in the lateral direction, the distance between the laser scanner and the reflective surface of the second reflecting unit that reflects the laser beam is measured respectively.

[0031] By offsetting the two reflective elements at least approximately perpendicularly relative to each other, the laser scanner is calibrated for different radiation angles of the laser beam. When the laser beam reaches the gap between the two reflective elements, it is reflected by the third reflective surface of the screens of the two reflective elements. The laser scanner's laser beam then extends horizontally over an angle greater than 90°.

[0032] According to an advantageous embodiment of the invention, the determined orientation of the laser scanner is indicated optically and / or acoustically. Thus, it is indicated optically and / or acoustically whether the laser scanner is tilted vertically upward, i.e., away from the ground, or whether the laser scanner is tilted vertically downward, i.e., toward the ground, or whether the laser scanner is oriented horizontally.

[0033] The present invention is not limited to the feature combinations of the claims. For a person skilled in the art, further meaningful combinations of the claims and / or individual claim features and / or features of the description and / or drawings will appear, in particular, from the task and / or the task arising from the comparison with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The invention will now be described in detail with reference to the accompanying drawings. The invention is not limited to the embodiments shown in the drawings. The drawings merely schematically illustrate the subject matter of the invention.

[0035] Figure 1 A schematic diagram of an apparatus for calibrating a laser scanner is shown;

[0036] Figure 2 shows a top view of the reflection unit;

[0037] Figure 3 shows a side view of the reflection unit;

[0038] Figure 4 shows a front view of the reflective unit;

[0039] Figure 5 shows a top view of a reflecting unit according to a first modification;

[0040] Figure 6 shows a perspective view of a reflecting unit according to a second modification;

[0041] Figure 7 A first graph with measured distances is shown;

[0042] Figure 8 showing a second graph with measured distances; and

[0043] Figure 9 A third graph with measured distances is shown. DETAILED DESCRIPTION

[0044] Figure 1 A schematic diagram shows a device for calibrating a laser scanner 3 of a vehicle 2. In this case, the vehicle 2 is an autonomous vehicle 2, in particular a self-propelled mobile transport system. Vehicle 2 has a roughly rectangular outline. Laser scanners 3 are arranged at two diagonally opposite corners of vehicle 2. Each laser scanner 3 emits a laser beam L, detects the reflected laser beam L, and calculates the distance D to the object that reflected the laser beam L. Each laser beam L emitted by the laser scanner 3 moves within an angular range of approximately 270°.

[0045] The laser scanner 3 is connected to a digital computer 4. During calibration of the laser scanner 3, data, in particular data about the measured distance D to the object, are transmitted from the laser scanner 3 to the digital computer 4. The digital computer 4 determines the orientation of the laser scanner 3 from the measured distance D and displays the determined orientation of the laser scanner 3 optically and acoustically.

[0046] The apparatus includes a first reflecting unit 21 for reflecting the laser beam L of the laser scanner 3 and a second reflecting unit 22 for reflecting the laser beam L of the laser scanner 3. The vehicle 2 and the reflecting units 21 and 22 are located on a flat ground. The reflecting units 21 and 22 are objects that reflect the laser beam L.

[0047] Each reflector unit 21, 22 has a front side that extends at least approximately perpendicular to the respective illumination direction S. The respective transverse direction Y extends perpendicular to the respective illumination direction S. The respective vertical direction Z extends perpendicular to the respective illumination direction S and perpendicular to the respective transverse direction Y. The aforementioned directional specifications, namely the vertical direction Z, the transverse direction Y, and the illumination direction S, are each defined relative to the respective reflector unit 21, 22. In this case, the vertical directions Z of the reflector units 21, 22 extend parallel to one another and perpendicular to the ground on which the reflector units 21, 22 and the vehicle 2 are located.

[0048] Each reflector unit 21 , 22 is oriented such that a laser beam L emitted by a laser scanner 3 of the vehicle 2 , which reaches the front side of the corresponding reflector unit 21 , 22 centrally in the corresponding transverse direction Y, extends at least approximately along the corresponding irradiation direction S. At a specific radiation angle, the laser beam L reaches the front side of the corresponding reflector unit 21 , 22 at least approximately perpendicularly.

[0049] The irradiation direction S of the first reflecting unit 21 extends at least approximately perpendicular to the irradiation direction S of the second reflecting unit 22. The irradiation direction S of the first reflecting unit 21 extends at least approximately parallel to the lateral direction Y of the second reflecting unit 22. Therefore, the radiation angle at which the laser beam L reaches the front side of the first reflecting unit 21 at least approximately perpendicularly is offset by at least approximately 90° from the radiation angle at which the laser beam L reaches the front side of the second reflecting unit 22 at least approximately perpendicularly.

[0050] Figure 2 Shown Figure 1 The figure shows a top view of one of the reflector units 21 and 22. Both reflector units 21 and 22 are designed identically. The reflector units 21 and 22 include a first shield 7, a second shield 8, and a screen 5. The first shield 7 is arranged between the second shield 8 and the screen 5 along the illumination direction S. The first shield 7 and the screen 5 are offset from each other by a first spacing A1 along the illumination direction S. The first shield 7 and the second shield 8 are offset from each other by a second spacing A2 along the beam direction S.

[0051] The reflector units 21 and 22 have two bases 6 that extend primarily in the vertical direction Z. Shields 7 and 8 are attached to the two bases 6 , with the base 6 being arranged between the first shield 7 and the second shield 8 in the illumination direction S. The two bases 6 are arranged offset relative to each other in the transverse direction Y. The extent of the two bases 6 in the illumination direction approximately corresponds to the second spacing A2.

[0052] Figure 3 The side view of the reflector units 21 and 22 is shown. The first shielding element 7 is arranged offset relative to the second shielding element 8 in the vertical direction Z. The shielding elements 7 and 8 are fixed to opposite sides of the base 6 in the irradiation direction S.

[0053] Figure 4 The figure shows a front view of the reflective units 21, 22, i.e., a view from the front side. The first shield 7 has a first reflective surface 31, which extends at least approximately perpendicularly to the illumination direction S. The second shield 8 has a second reflective surface 32, which also extends at least approximately perpendicularly to the illumination direction S. The screen 5 has a third reflective surface 33, which also extends at least approximately perpendicularly to the illumination direction S.

[0054] The first shield 7 is arranged offset relative to the second shield 8 in the vertical direction Z such that a gap 9 is formed between the first shield 7 and the second shield 8 , which gap extends in the vertical direction Z and in the transverse direction Y. The gap 9 is delimited in the transverse direction Y by the two bases 6 . Figure 1 The first reflecting unit 21 and the second reflecting unit 22 are oriented such that the gap 9 of the first reflecting unit 21 and the gap 9 of the second reflecting unit 22 are aligned with each other in the vertical direction Z.

[0055] The screen 5 is constructed and arranged so that the projection of the gap 9 in the illumination direction S falls entirely on the third reflective surface 33 of the screen 5. The extension dimension of the third reflective surface 33 of the screen 5 along the vertical direction Z is greater than the extension dimension of the gap 9 along the vertical direction Z, and the extension dimension of the third reflective surface 31 of the screen 5 along the transverse direction Y is greater than the extension dimension of the gap 9 along the transverse direction Y.

[0056] Figure 5 A top view of a reflective unit 21, 22 according to a first modification is shown. The reflective units 21, 22 have two spacers 10 arranged such that the first shield 7 and the screen 5 are offset from each other by a first spacing A1 along the illumination direction S. The two spacers 10 are each arranged between one of the bases 6 and the second screen 5 along the illumination direction S.

[0057] The reflector units 21 and 22 further include two partitions 11, which are arranged adjacent to the second shield 8 and the first shield 7 in the transverse direction Y. The shields 7 and 8 and the base 6 are thus arranged between the two partitions 11 in the transverse direction Y. The two partitions 11 each have two reflective surfaces, which are arranged at an angle relative to each other. The two reflective surfaces of the partitions 11 each extend parallel to the vertical direction Z. The two reflective surfaces of the partitions 11 each extend at an angle relative to the illumination direction S and relative to the transverse direction Y.

[0058] Figure 6A perspective view of a reflector unit 21, 22 according to a second modification is shown. The reflector units 21, 22 include a screen 5 (not shown here), in addition to a first shield 7, a second shield 8, and two bases 6. The reflector units 21, 22 also include a crossbeam 16, which is fixed to the bases 6 and extends between the bases 6 in a transverse direction Y. The crossbeam 16 serves to mechanically stabilize the reflector units 21, 22.

[0059] The first reflective surface 31 of the first shield 7 has the same reflective area, which is the surface of black ESD foam. The second reflective surface 32 of the second shield 8 includes a first reflective area 12 , a second reflective area 13 , a third reflective area 14 and a fourth reflective area 15 .

[0060] The first reflective region 12 is the surface of black ESD foam. The second reflective region 13, the third reflective region 14, and the fourth reflective region 15 are each the surface of an aluminum sheet. Therefore, the first reflective region 12 has different reflective properties for the laser beam L than the remaining reflective regions 13, 14, and 15 of the second shield 8.

[0061] The third reflecting area 14 is located on one edge of the second shield 8 in front of one base 6 along the transverse direction Y. The fourth reflecting area 15 is located on the other edge of the second shield 8 in front of the other base 6 along the transverse direction Y. The first reflecting area 12 extends between the bases 6 along the transverse direction Y. The second reflecting area 13 is centrally located between the bases 6 and extends along the transverse direction Y over a portion of the extension of the first reflecting area 12.

[0062] For calibration Figure 1 One of the laser scanners 3 shown, the laser beam L of the laser scanner 3 is directed to Figure 6 The reflecting units 21 and 22 are shown. Obviously, Figures 2 to 5 One of the reflective units 21, 22 shown is also suitable for calibrating the laser scanner 3. Here, a laser beam L is moved along the reflective units 21, 22 in a transverse direction Y. The laser beam L sweeps through a range of radiation angles. Each position P of the laser beam L in the transverse direction Y corresponds to a specific radiation angle of the laser beam L. For each of the multiple positions P of the laser beam L in the transverse direction Y, the distance D of the laser scanner 3 from the reflection surface 31, 32, 33 from which the laser beam L is reflected is measured. The orientation of the laser scanner 3 is then determined based on the measured distances D.

[0063] In the transverse direction Y, in the middle of the reflector units 21 and 22, the laser beam L extends at least approximately along the irradiation direction S and there reaches the reflector units 21 and 22 at least approximately perpendicularly. When the distance of the laser scanner 3 from the reflector units 21 and 22 in the irradiation direction S is significantly greater than the extent of the reflector units 21 and 22 in the transverse direction Y, the radiation angle of the laser beam L is approximately proportional to the position P of the laser beam L in the transverse direction Y. If this approximation is not accurate enough, the polar coordinates provided by the laser scanner 3, namely, the radiation angle and the distance D, are converted into Cartesian coordinates, namely, the position P in the transverse direction Y and the distance D in the irradiation direction S.

[0064] Figure 7 A first diagram is shown with distances D measured as a function of the position P of the laser beam L in the transverse direction Y. The position P of the laser beam L is divided into five segments B1 , B2 , B3 , B4 , B5 .

[0065] In the first section B1, the laser beam L passes laterally through one base 6 to reach the screen 5 and is reflected by the third reflective surface 33. In the second section B2, the laser beam L reaches one base 6 and is reflected by it. In the third section B3, the laser beam L passes through the gap 19 to reach the screen 5 and is reflected by the third reflective surface 33. In the fourth section B4, the laser beam L reaches the other base 6 and is reflected by it. In the fifth section B5, the laser beam L passes laterally through the other base 6 to reach the screen 5 and is reflected by the third reflective surface 33.

[0066] The predefined target range F in the first diagram describes the distance D of the laser scanner 3 to the screen 5 with a predefined tolerance. In the third section B3, the measured distance D lies within the aforementioned target range F. Therefore, the laser beam L extends in the horizontal direction and the laser scanner 3 is oriented horizontally.

[0067] Figure 8 A second diagram is shown with distances D measured as a function of the position P of the laser beam L in the transverse direction Y. The position P of the laser beam L is divided into five segments B1 , B2 , B3 , B4 , B5 .

[0068] In the first section B1, the laser beam L passes laterally through one base 6 and reaches the screen 5, where it is reflected by the third reflective surface 33. In the second section B2, the laser beam L reaches the third reflective area 14 of the second shield 8 and is reflected by it. In the third section B3, the laser beam L alternately reaches the first reflective area 12 and the second reflective area 13 of the second shield 8 and is reflected by them respectively. In the fourth section B4, the laser beam L reaches the fourth reflective area 15 of the second shield 8 and is reflected by it. In the fifth section B5, the laser beam L passes laterally through the other base 6 and reaches the screen 5, where it is reflected by the third reflective surface 33.

[0069] The predefined target range F in the second diagram describes the distance D from the laser scanner 3 to the screen 5 with a predefined tolerance. Within the third section B3, the measured distance D lies outside this target range F. Due to the different reflection properties of the first and second reflection areas 12 and 13, the measured distance D in the third section B3 changes abruptly. Consequently, the laser beam L extends downward in the vertical direction Z, and the laser scanner 3 is tilted downward in the vertical direction Z, i.e., toward the ground.

[0070] Figure 9 A third diagram is shown with distances D measured as a function of the position P of the laser beam L in the transverse direction Y. The position P of the laser beam L is divided into five segments B1 , B2 , B3 , B4 , B5 .

[0071] In the first section B1, the laser beam L passes laterally through one base 6 and reaches the screen 5, where it is reflected by the third reflective surface 33. In the second section B2, the laser beam L reaches one base 6 and is reflected by it. In the third section B3, the laser beam L reaches the first shield 7 and is reflected by the first reflective surface 31. In the fourth section B4, the laser beam L reaches the other base 6 and is reflected by it. In the fifth section B5, the laser beam L passes laterally through the other base 6 and reaches the screen 5, where it is reflected by the third reflective surface 33.

[0072] The predefined target range F in the third diagram describes the distance D from the laser scanner 3 to the screen 5 with a predefined tolerance. Within the third section B3, the measured distance D lies outside the aforementioned target range F. The measured distance D in the third section B3 is approximately constant. The laser beam L therefore extends upward in the vertical direction Z, and the laser scanner 3 is tilted upward in the vertical direction Z, i.e., away from the ground.

[0073] Reference Signs List

[0074] 2 vehicles

[0075] 3 laser scanners

[0076] 4 Digital Computer

[0077] 5 screens

[0078] 6 base

[0079] 7 First shielding member

[0080] 8 Second shielding member

[0081] 9 Gap

[0082] 10 spacers

[0083] 11 partitions

[0084] 12 First reflection area

[0085] 13 Second reflection area

[0086] 14Third reflection area

[0087] 15 Fourth reflection area

[0088] 16 beams

[0089] 21 first reflection unit

[0090] 22 second reflection unit

[0091] 31 first reflecting surface

[0092] 32 second reflection surface

[0093] 33 third reflecting surface

[0094] A1 first spacing

[0095] A2 second spacing

[0096] B1 first section

[0097] B2 second section

[0098] B3 third section

[0099] B4 Section 4

[0100] B5 Section 5

[0101] D distance

[0102] F Target Range

[0103] L laser beam

[0104] P position

[0105] S irradiation direction

[0106] Y horizontal direction

[0107] Z vertical direction.

Claims

1. A device for calibrating a laser scanner (3), comprising at least one reflecting unit (21, 22) for reflecting a laser beam (L) of the laser scanner (3), characterized in that At least one reflecting unit (21, 22) comprises a first shield (7), a second shield (8) and a screen (5), wherein the first shield (7) is arranged between the second shield (8) and the screen (5) along an irradiation direction (S), wherein the first shield (7) has a first reflecting surface (31) extending at least approximately perpendicular to the irradiation direction (S), the second shield (8) has a second reflecting surface (32) extending at least approximately perpendicular to the irradiation direction (S), and the screen (5) has a second reflecting surface (32) extending at least approximately perpendicular to the irradiation direction (S). ), wherein the first shielding member (7) is arranged offset relative to the second shielding member (8) in the vertical direction (Z) so that a gap (9) is formed between the first shielding member (7) and the second shielding member (8), and the gap extends in the vertical direction (Z) and the transverse direction (Y), wherein the screen (5) is constructed and arranged so that a projection of the gap (9) in the irradiation direction (S) falls completely on the third reflecting surface (33) of the screen (5), wherein the vertical direction extends perpendicular to the irradiation direction.

2. The device according to claim 1, characterized in that The extension dimension of the third reflecting surface (33) of the screen (5) along the vertical direction (Z) is greater than the extension dimension of the gap (9) along the vertical direction (Z), and the extension dimension of the third reflecting surface (33) of the screen (5) along the transverse direction (Y) is greater than the extension dimension of the gap (9) along the transverse direction (Y).

3. The device according to claim 1 or 2, characterized in that The device comprises a first reflecting unit (21) and a second reflecting unit (22), the first reflecting unit and the second reflecting unit being oriented such that an irradiation direction (S) of the first reflecting unit (21) and an irradiation direction (S) of the second reflecting unit (22) extend at least approximately perpendicularly.

4. The device according to claim 3, characterized in that The first reflecting unit (21) and the second reflecting unit (22) are oriented such that an irradiation direction (S) of the first reflecting unit (21) extends at least approximately parallel to a transverse direction (Y) of the second reflecting unit (22).

5. The device according to claim 3, characterized in that The first reflecting unit (21) and the second reflecting unit (22) are oriented such that a vertical direction (Z) of the first reflecting unit (21) extends parallel to a vertical direction (Z) of the second reflecting unit (22).

6. The device according to claim 3, characterized in that The first reflecting unit (21) and the second reflecting unit (22) are oriented such that the gap (9) of the first reflecting unit (21) and the gap (9) of the second reflecting unit (22) are aligned with each other in a vertical direction (Z).

7. The device according to claim 1 or 2, characterized in that At least one reflecting unit (21, 22) has at least one spacer (10) which is arranged so that the first shielding member (7) and the screen (5) are arranged to be offset from each other by a first distance (A1) along an irradiation direction (S).

8. The device according to claim 1 or 2, characterized in that At least one reflecting unit (21, 22) has at least one base (6), which extends mainly in a vertical direction (Z) and is arranged so that the first shield (7) and the second shield (8) are arranged to be offset from each other by a second distance (A2) along an irradiation direction (S).

9. The device according to claim 1 or 2, characterized in that At least one reflecting unit (21, 22) has at least one partition (11), which is arranged next to the second shielding element (8) and / or the first shielding element (7) along the transverse direction (Y), and at least one partition (11) has at least two reflecting surfaces, which are arranged obliquely to each other.

10. The device according to claim 1 or 2, characterized in that The first reflecting surface (31) of the first shielding element (7) and / or the second reflecting surface (32) of the second shielding element (8) include a first reflecting area (12) and a second reflecting area (13), wherein these reflecting areas (12, 13) have different reflecting properties, in particular different colors and / or different surface materials.

11. The device according to claim 1 or 2, characterized in that The first reflecting surface (31) of the first shielding element (7) and / or the first reflecting area (12) of the second reflecting surface (32) of the second shielding element (8) are covered with black foam.

12. The device according to claim 1 or 2, characterized in that At least the edges of the first shielding part (7) and / or the edges of the second shielding part (8) adjacent to the gap (9) of the reflective units (21, 22) are covered with black foam.

13. A method for calibrating a laser scanner (3) by means of a device according to any one of the preceding claims, characterized in that The laser beam (L) of the laser scanner (3) is aligned at least approximately along an irradiation direction (S) with at least one reflecting unit (21, 22), and the laser beam (L) moves along at least one reflecting unit (21, 22) in a transverse direction (Y). For a plurality of positions (P) of the laser beam (L) in the transverse direction (Y), the distance (D) between the laser scanner (3) and a reflecting surface (31, 32, 33) reflecting the laser beam (L) is measured respectively, and the orientation of the laser scanner (3) is determined based on the measured distance (D) between the laser scanner (3) and the corresponding reflecting surface (31, 32, 33).

14. The method according to claim 13, characterized in that The device comprises a first reflecting unit (21) and a second reflecting unit (22), wherein the first reflecting unit and the second reflecting unit are oriented such that an irradiation direction (S) of the first reflecting unit (21) and an irradiation direction (S) of the second reflecting unit (22) extend at least approximately perpendicularly, wherein a laser beam (L) of the laser scanner (3) is aligned with the first reflecting unit (21) at least approximately along the irradiation direction (S) of the first reflecting unit (21), and the laser beam (L) moves along the first reflecting unit (21) in a transverse direction (Y) of the first reflecting unit (21), and for a plurality of positions (P) of the laser beam (L) in the transverse direction (Y), respectively The invention relates to a method for measuring a distance (D) between the laser scanner (3) and a reflection surface (31, 32, 33) of a first reflection unit (21) reflecting a laser beam (L), aligning the laser beam (L) of the laser scanner (3) at least approximately along an irradiation direction (S) of the second reflection unit (22) toward the second reflection unit (22), and moving the laser beam (L) along the second reflection unit (22) in a transverse direction (Y) of the second reflection unit (22). For a plurality of positions (P) of the laser beam (L) in the transverse direction (Y), respectively measuring the distance (D) between the laser scanner (3) and the reflection surface (31, 32, 33) of the second reflection unit (22) reflecting the laser beam (L).

15. The method according to claim 13 or 14, characterized in that The determined orientation of the laser scanner (3) is indicated optically and / or acoustically.

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