Online calibration of lidar devices

Abstract

A method for calibrating a laser radar device is disclosed, wherein a beam is generated and emitted by a beam source, the beam reflected and / or backscattered by objects in a scanning area of the laser radar device and the beam reflected and / or backscattered by a reflection structure applied on a cover glass of the laser radar device are received by a detector, a reflection pattern is determined on the basis of the beam reflected and / or backscattered by the reflection structure applied on the cover glass, and the reflection pattern is compared with a reference pattern, and in the event of a deviation between the determined reflection pattern and the reference pattern, at least one correction measure for calibrating the laser radar device is performed. Furthermore, a method for determining a fogged cover glass of a laser radar device and a laser radar device are disclosed.

Description

Technical Field

[0001] This invention relates to a method for calibrating a lidar device. Additionally, this invention relates to a method for determining the fogging (beschlagenen) covering glass of a lidar device, and a lidar device itself. Background Technology

[0002] LiDAR (Light Detection and Ranging) devices are an essential component of vehicles capable of automated operation and enable various driving functions. After manufacturing, the LiDAR device is calibrated in the factory to ensure compliance with requirements regarding measurement angles and scanning range. Furthermore, LiDAR devices used in vehicles need to remain operational under varying weather conditions and temperatures. Especially in low-temperature environments, additional heating structures are used in the cover glass or protective glass of the LiDAR device to prevent fogging due to humidity or icing.

[0003] During operation, the mechanical, optical, and electrical properties of various components of a lidar device can change due to environmental factors such as temperature, as well as component aging. Consequently, static calibration, especially for angle and distance measurements, may no longer be effective. Detection of these changes and matching of calibration values ​​can be achieved through continuous analysis of the lidar device's point cloud using so-called sensing algorithms. Furthermore, it is known to monitor reference points within the housing during dark periods, or outside of the lidar device's normal operation. Summary of the Invention

[0004] The objective of this invention can be viewed as proposing a cost-effective and technically simple method for online calibration of lidar equipment.

[0005] This task is accomplished using a method for calibrating a lidar device and a lidar device for scanning a scanning area. Advantageous configurations of the invention are also given below.

[0006] According to one aspect of the present invention, a method for calibrating a lidar device is provided. For this purpose, in one step, a beam is generated and emitted by a beam source.

[0007] The detector receives beams reflected and / or backscattered by objects in the scanning area of ​​the lidar device, and beams reflected and / or backscattered by reflective structures applied to the cover glass of the lidar device.

[0008] Based on the illumination of the scanning area, the reflective structure arranged on the cover glass can also be illuminated, and the detector can identify the corresponding backscattered beam. Thus, the detector can receive the beam reflected from the reflective structure and the beam reflected from the scanning area outside the lidar device.

[0009] In another step, a reflection pattern is obtained based on the beams reflected and / or backscattered by the reflective structure applied to the cover glass, and the reflection pattern is compared with a reference pattern.

[0010] During subsequent analysis and processing of the received beam, the reflection pattern generated by the reflecting structure can be extracted. Preferably, the reflection pattern can be distributed and arranged according to the geometry of the reflecting structure.

[0011] If there is a deviation between the obtained reflection pattern and the reference pattern, at least one correction measure for calibrating the lidar device shall be performed.

[0012] The reference pattern can be obtained during the manufacturing of the lidar device or when the lidar device is first started operating, and can be stored in the control device. Then, this initially obtained reference pattern can be used as a comparison pattern for the obtained reference pattern in order to determine the deviation from the initial boundary conditions or factory-side calibration values.

[0013] This method enables long-term reliable operation of lidar equipment based on online calibration. This online calibration can be performed continuously or at defined time intervals while the lidar equipment is running.

[0014] The reflective structure can be configured, for example, as a heating structure in the cover glass or protective glass of a lidar device, the heating structure having a defined location and reflectivity.

[0015] Depending on the shape and orientation of the reflective structure, the method enables the detection of displacement and distortion of the field of view in the horizontal and / or vertical directions during normal operation of the lidar device.

[0016] Here, the method is based on the basic idea that the reflective structure in the covering glass has a reflectivity that is different from that of an object outside the lidar device.

[0017] Conductive, engraved, and / or electrically insulating materials can be used to realize the reflective structure. For example, transparent materials such as indium tin oxide and thin metal layers, or opaque materials such as metal wires, can be used as conductive materials. The position of the reflective structure can be accurately determined horizontally and vertically based on the location of the reflection or echo or changes in local background light. The reflected beam, or the beam reflected from the reflective structure, remains within the lidar device, making the influence of external factors on the measurement negligible.

[0018] Furthermore, in the case of pixelated detectors, such as CMOS or CCD detectors, the location and distribution of the intensity distribution generated by the reflective structure can be determined by analyzing the detector image.

[0019] Here, the position of the reflective structure in the cover glass can be determined during operation, and deviations from the values ​​obtained during manufacturing can be detected. When a deviation is identified, the field of view can be corrected accordingly.

[0020] As possible calibration measures for lidar equipment, corrections can be performed when analyzing and processing the detector's measurement data and / or when the beam is deflected. For example, the deflection angle of the deflector can be decreased or increased by matched electronic manipulation. Alternatively or additionally, software-based corrections can be performed on deviations from factory-side parameters when analyzing and processing the received beam.

[0021] The method described here can be implemented with minimal additional cost and without requiring additional structural space. In particular, there are numerous possibilities for the arrangement, structuring, or design of reflective structures. This allows for extensive online calibration of the angular position within the field of view or scanning area of ​​the lidar device.

[0022] Here, online calibration of the lidar equipment can be performed in parallel with normal operation, eliminating the need for additional switching on of the lidar equipment during dark periods or when in standby mode.

[0023] In another embodiment, the reflection pattern is obtained by reflecting and / or backscattering the beam through a reflective structure configured as a heating structure. Thus, the heating structure already installed in the cover glass of the lidar device can be additionally used for online calibration. Besides preventing fogging and freezing of the cover glass, the heating structure also fulfills additional functions.

[0024] According to another aspect of the present invention, a method is provided for determining the fogging of the cover glass of a lidar device. For this purpose, a beam is generated and emitted by a beam source of the lidar device.

[0025] The detector receives beams reflected and / or backscattered by objects in the scanning area of ​​the lidar device, and beams reflected and / or backscattered by reflective structures applied to the cover glass of the lidar device.

[0026] Then, the reflectivity distribution of the reflective structure is determined based on the beam received on the detector.

[0027] In another step, the reflectivity distribution is compared with a reference distribution, wherein, if there is a deviation between the reflectivity distribution and the reference distribution, the fogging cover glass is determined.

[0028] Similar to the determination of reflection patterns, the reflectivity distribution of the detector image can be used to determine whether the cover glass of a lidar device is covered by steam or ice.

[0029] Here, spatially resolved reflectivity can be evaluated to determine the fogging state of the cover glass. In particular, it is possible to use a comparison of the reflectivity of the reflective structures within the reflectivity of the cover glass to determine the fogging state.

[0030] According to one embodiment, the heating structure of the cover glass is activated and / or controlled based on the degree of deviation between the reflectivity distribution and a reference distribution. This measure allows for the manipulation of the heating structure on the cover glass based on monitoring the fogging state of the cover glass. In particular, the electrical power of the heating structure can be adjusted according to the fogging state. In cases of low fogging, the heating structure can operate with reduced electrical power. This results in increased energy efficiency of the heating structure.

[0031] According to another aspect of the present invention, a lidar device for scanning a scanning area is provided. The lidar device has at least one beam source for generating and emitting a beam into the scanning area. Additionally, the lidar device has at least one detector for receiving the beam reflected and / or backscattered from the scanning area, wherein the beam source and the detector are arranged in a manner protected by a covering glass. Furthermore, a control device is provided for manipulating the beam source and analyzing the detector, wherein the lidar device is configured to implement at least one of the methods according to the present invention.

[0032] LiDAR equipment can be configured to implement methods for calibration and / or for determining the appearance of fogged cover glass. The control equipment can analyze and process the corresponding reflectivity distribution or reflection pattern based on the measurement data received by the detector.

[0033] Here, the lidar device can be configured as a rotating system, a scanning system, or a flash system. The method described allows for cost-effective and technically simple calibration of the lidar device.

[0034] According to one embodiment, a reflective structure is disposed on the inner surface of the cover glass or between the first and second cover glass layers. The reflective structure and / or heating structure can be disposed on the inner surface of the cover glass or between the two cover glass layers in a manner protected from external influences, either as a coating or by adhesive. This also eliminates external influences on online calibration.

[0035] According to another embodiment, the reflective structure is arranged either within or outside the scanning area of ​​the lidar device. Since the field of view used is typically smaller than the actual measurable field of view or scanning area of ​​the lidar device, the extra area can be used to position the reflective structure there. This reflective structure can, for example, be configured as an input line (Zuleitung) for a uniform, transparent heating layer.

[0036] In addition, this arrangement of reflective structures outside the scanning area provides greater design freedom in terms of size, shape, and reflectivity, allowing online calibration to be further optimized without hindering the operation of the lidar device.

[0037] According to another embodiment, the reflective structure is configured as a heating structure, wherein the reflective structure configured as a heating structure has multiple electrical heating lines and / or input lines leading to the heating lines. The corresponding heating lines or input lines can be considered as a reflective structure to allow for calibration of the lidar device during operation. This measure eliminates the need for additional modifications for calibrating the lidar device.

[0038] According to another embodiment, the electric heating lines and / or input lines leading to the heating lines extend diagonally, vertically and / or horizontally, along the cover glass. The heating structure can be positioned throughout the entire field of view and can extend horizontally and / or vertically. For example, the heating lines and / or input lines can form a grid. Thus, distortion can be detected not only in the horizontal direction but also in the vertical direction. Furthermore, the combined arrangement improves the uniformity of temperature distribution on the cover glass, making de-icing of the cover glass more effective. Attached Figure Description

[0039] Preferred embodiments of the invention are described in more detail below with reference to greatly simplified schematic diagrams. As shown herein:

[0040] Figure 1A schematic diagram of a lidar device according to one embodiment is shown.

[0041] Figure 2 A schematic diagram of a lidar device according to another embodiment is shown.

[0042] Figure 3 A schematic perspective view is shown through a glass cover with electrical lines extending in the horizontal direction.

[0043] Figure 4 A schematic perspective view showing a view through a glass cover with electrical lines extending in the vertical direction.

[0044] Figure 5 A schematic perspective view is shown through a glass cover with electrical lines extending in both the horizontal and vertical directions.

[0045] Figure 6 A schematic perspective view showing the view through a cover glass with a reflective structure outside the scanning range, and

[0046] Figures 7-9 A schematic reflectivity distribution is shown to illustrate a method for determining the reflectivity of fogging covered glass. Detailed Implementation

[0047] Figure 1 A schematic diagram of a lidar device 1 according to one embodiment is shown. The lidar device 1 is used to scan a scanning area A and is configured, for example, as a rotating lidar device 1. Here, the beam source 2 and detector 4 of the lidar device 1 can rotate or pivot about a rotation axis R.

[0048] Detector 4 and beam source 2 are arranged in the lidar device 1, protected by a covering glass 6. In the illustrated embodiment, the covering glass 6 is implemented in a tubular or circular shape and surrounds detector 4 and beam source 2. Detector 4 can be arranged, for example, along a rotation axis R in a height offset relative to beam source 2.

[0049] The entire cover glass 6 is not used to scan the scanning area A. The used section 8 of the cover glass 6 is used to emit the generated beam 3 into the scanning area A.

[0050] In the illustrated embodiment, the segment 8 used for scanning region A corresponds to approximately 180°, or half of the cover glass 6. Additionally, the cover glass 6 has segments 10 that are not used for scanning region A.

[0051] A reflective structure 12 is arranged on the cover glass 6. The reflective structure 12 can be arranged, for example, on the inner side 7 of the cover glass 6 or as... Figure 2It is arranged as shown between two covering glass layers 6.1 and 6.2. The reflective structure 12 can be used solely for reflecting the generated beam 3, or it can have an additional heating function.

[0052] The generated beam 3 scans the scanning area A, enabling the detection of the object 14 arranged within the scanning area A. Here, the generated beam 3 is reflected or backscattered by the object 14. The beam 5 reflected and / or backscattered by the object 14 is received by the detector 4. Additionally, the generated beam 3 is also reflected or backscattered by the reflecting structure 12. The beam 13 reflected and / or backscattered by the reflecting structure 12 is also received by the detector 4.

[0053] The lidar device 1 includes a control device 16, which is configured to manipulate the beam source 2 and receive and analyze measurement data from the detector 4. In addition, the control device 16 can be used to manipulate and adjust the reflective structure 12, which is configured as a heating structure.

[0054] By analyzing and processing the reflected and / or backscattered beams 5 and 13, the position of the reflecting structure 12 can be determined by the control device and used to perform online calibration.

[0055] exist Figure 2 A schematic diagram of a lidar device 1 according to another embodiment is shown. (The diagram is incomplete and requires further context.) Figure 1 Unlike the embodiment shown, this lidar device has a cover glass 6, which is essentially composed of segments 8 for scanning the scanning area A. The cover glass 6 is configured as segments or sections of cover glass covering 360°.

[0056] The cover glass 6 consists of a first cover glass layer 6.1 and a second cover glass layer 6.2. The reflective structure 12 is arranged between the two cover glass layers 6.1 and 6.2.

[0057] The lidar device 1 can be configured as a scanning system in which a deflection element 18, for example, deflects the generated beam 3 along the scanning area A. For example, the deflection element 18 can be a Spiegel or a prism.

[0058] exist Figure 3 The diagram shows a schematic perspective view through a cover glass 6 having an electrical line (elektrischen Leitungen) 20 extending in the horizontal direction H. The electrical line 20 forms a reflective structure 12 configured as a heating structure and can be obtained by a detector 4 for use in online calibration or for detecting fogging of the cover glass 6.

[0059] This diagram shows section 8, which is used to scan area A, and section 10, which is not used to scan area A. The electrical line 20 extends through both sections 8 and 10.

[0060] Figure 4 A schematic perspective view is shown through a cover glass 6 having an electrical line 20 extending in the vertical direction V, the electrical line configuration being a heating structure.

[0061] Here, the electrical line 20 can be directly or indirectly connected to the control device 16. Here, the control device 16 can regulate the current conducted through the electrical line 20 in order to prevent fogging or icing of the covered glass 6.

[0062] Figure 5 A schematic perspective view is shown of a covering glass 6 through which electrical lines 20 extend in the horizontal direction H and the vertical direction V. This allows for the realization of… Figure 3 Neutralization Figure 4 The combination of the cover glass 6 shown in the figure enables uniform heat distribution on the segment 8 used for scanning the scanning area A.

[0063] exist Figure 6 The diagram shows a schematic perspective view of the cover glass 6 passing through the reflective structure 12 outside the section 8 used for scanning the scanning area A. Thus, the section 8 of the cover glass 6 used for scanning the scanning area A can remain free of the reflective structure 12. For example, the reflective structure 12 can be obtained by briefly pivoting the beam source 2 and detector 4 beyond the section 8 to perform online calibration.

[0064] Figure 7 , Figure 8 and Figure 9 A schematic reflectance distribution RV is shown to illustrate a method for determining the reflectance of a fogging cover glass 6. Here, the reflectance distribution RV has a reflectance 22 of the object 14 in the scanning area A and a reflectance 24 of the reflective structure 12.

[0065] Here, the reflectivity 22 of the object 14 is determined based on the beam 5 reflected and / or backscattered by the object 14. The reflectivity 24 of the reflecting structure 12 is determined by receiving and analyzing the beam 13 reflected and / or backscattered by the reflecting structure 12.

[0066] Figure 7 A reference reflectance distribution is shown, corresponding to the reflectance distribution RV of the unfogled cover glass 6. Figure 8 The image shows the reflectance distribution RV of the slightly or rather, slightly fogged covering glass 6. (By...) Figure 9 The reflectivity distribution RV of the heavily fogged covered glass 6 was obtained.

[0067] It can be seen that as the degree of fogging of the covering glass 6 increases, the contrast between the reflectivity 22 of the object 14 in the scanning area A and the reflectivity 24 of the reflective structure 12 decreases, and the transition between the two reflectivities 22 and 24 becomes blurred.

Claims

1. A method for calibrating a lidar device (1), wherein, - A beam (3) is generated and emitted by a beam source (2). - The detector (4) receives the beam (5) reflected and / or backscattered by the object (14) in the scanning area (A) of the lidar device (1) and the beam (13) reflected and / or backscattered by the reflective structure (12) applied to the cover glass (6) of the lidar device (1). - A reflection pattern is obtained based on the reflected and / or backscattered beam (13) from the reflection structure (12) applied to the cover glass (6), and the reflection pattern is compared with a reference pattern. - In the event of a deviation between the obtained reflection pattern and the reference pattern, at least one correction measure is performed to calibrate the lidar device (1).

2. The method according to claim 1, wherein, The reflection pattern is obtained by reflecting and / or backscattering the beam (13) through a reflective structure (12) configured as a heating structure.

3. A method for determining the fogging cover glass (6) of a lidar device (1), wherein, - A beam (3) is generated and emitted by the beam source (2) of the lidar device (1). - The detector (4) receives the beam (5) reflected and / or backscattered by the object (14) in the scanning area (A) of the lidar device (1) and the beam (13) reflected and / or backscattered by the reflective structure (12) applied to the cover glass (6) of the lidar device (1). - Based on the received beam, determine the reflectivity distribution of the reflectivity (24) of the reflective structure (12) and at least one reflectivity (22) of the scanning area. - Compare the reflectance distribution with a reference distribution, wherein if there is a deviation between the reflectance distribution and the reference distribution, determine the fogging cover glass (6).

4. The method according to claim 3, wherein, The at least one reflectance (22) of the scanned area is at least one reflectance (22) of the object (14) in the scanned area (A).

5. The method according to claim 3 or 4, wherein, The heating structure (12) of the cover glass (6) is activated and / or controlled according to the degree of deviation between the reflectivity distribution and the reference distribution.

6. A lidar device (1) for scanning a scanning area (A), the lidar device having at least one beam source (2) for generating a beam (3) and for emitting the beam (3) into the scanning area (A), the lidar device having at least one detector (4) for receiving a beam (5) reflected and / or backscattered from the scanning area (A), wherein, The beam source (2) and the detector (4) are arranged in a manner protected by a covering glass (6), and the lidar device has a control device (16) for manipulating the beam source (3) and for analyzing and processing the detector (4), characterized in that the lidar device (1) is configured to implement at least one of the methods according to any one of claims 1 to 5.

7. The lidar device according to claim 6, wherein, The reflective structure (12) is arranged on the inner surface of the cover glass (6), or between the first cover glass layer (6.1) and the second cover glass layer (6.2).

8. The lidar device according to claim 6 or 7, wherein, The reflective structure (12) is arranged in the section (8) of the cover glass (6) of the lidar device (1) for scanning the scanning area (A), or outside the section (8) of the cover glass (6) of the lidar device (1) for scanning the scanning area (A).

9. The lidar device according to claim 6 or 7, wherein, The reflective structure (12) is configured as a heating structure, wherein the reflective structure (12) configured as a heating structure has a plurality of electric heating lines (20) and / or input lines leading to the heating lines (20).

10. The lidar device according to claim 9, wherein, The electric heating circuit (20) and / or the input circuit to the heating circuit (20) extend along the cover glass (6) in the vertical direction (V), in the horizontal direction (H) and / or diagonally.

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