LiDAR system with integrated contamination detection and corresponding method for contamination detection

Abstract

LiDAR system (100), comprising: a) a transmitting unit (10) designed to emit electromagnetic radiation (12) directed into the environment (60) of the LiDAR system (100); b) a receiver unit (20) configured to detect a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered from the environment (60) of the LiDAR system (100) into the LiDAR system (100); c) an exit window (30) designed to delimit the LiDAR system (100) from the environment (60) at least in the direction of radiation from the transmitting unit (10), wherein the electromagnetic radiation (12) emitted by the transmitting unit (10) is transmitted through the exit window (30) into the environment (60); wherein d) the LiDAR system (100) further comprises a contamination sensor (40) configured to detect a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered into the LiDAR system (10) from a surface (32, 33) of the exit window (30), wherein a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered into the LiDAR system (100) from a surface (32, 34) of the exit window (30) is imaged onto the contamination sensor (40) via an imaging optic (42).

Description

[0001] The present invention relates to a LiDAR system with integrated contamination detection and a corresponding method for contamination detection. State of the art

[0002] Contamination detection systems typically consist of a light source (transmitter for electromagnetic radiation) and a detector (receiver for electromagnetic radiation). The transmitter and receiver can be configured for transmission or reflection. The receiver determines the amount of light scattered by contaminants on the surface being monitored, which represents the degree of contamination. Other methods rely on evaluating the image on the detector (e.g., PIN diode, CCD, CMOS, APD, SPAD chip, or arrays thereof) using appropriate algorithms to infer the amount of contamination. Contaminants are generally considered to be surface deposits of individual particles (e.g., dust, pollen), water, snow, etc.

[0003] From US patent 2012 / 0182553 A1, a method for estimating the degree of soiling of the front lens of an optical detection device and an optical detection device are disclosed in particular. A method and a device for optically detecting soiling are also disclosed in EP 1 983 334 B1. EP 1988389 B1 relates to the monitoring of a spatial area with determination of the degree of soiling of a transparent interface based on image contrast.

[0004] Currently, optoelectronic 3D sensors (LiDAR - light detection and ranging) do not incorporate sensors that can detect contamination of the corresponding exit or outer window (also known as the cover glass) and thus provide information about the system's availability. In particular, the type and extent of contamination therefore remain unknown to the LiDAR system.

[0005] Document DE 10 2016 111 615 B3 discloses an optoelectronic sensor in which the angular position of a rotatable deflection unit is detected by means of a moving image sensor that detects relative movement with respect to a stationary part of the sensor. Furthermore, contamination of a front glass of the sensor is detected from the signal of this image sensor.

[0006] Document EP 3 232 224 A1 discloses a distance-measuring optoelectronic sensor with at least two sampling memories having partially overlapping recording areas. These are configured to record a received signal for a longer duration than the time interval between two successive transmitted light pulses, in order to increase the uniqueness range of the distance measurement.

[0007] Document DE 10 2008 030 611 A1 discloses an optical sensor for measuring visibility using the pulse time-of-flight method, in which the ratio of transmit power to receive power is intermittently calibrated. Simultaneously, the transmittance of the optical transmission windows is measured and taken into account when evaluating the visibility.

[0008] Document WO 2007 / 036557 A1 discloses a device for capturing distance images that achieves multi-target capability through the temporal resolution of light pulses reflected from object regions at different distances. This is accomplished by determining extreme values ​​of the slope of a correlation function between the received light pulses and a variable time window. Disclosure of the invention

[0009] According to the invention, an optoelectronic 3D sensor system (LiDAR system) is provided which avoids or at least significantly reduces the problems encountered in the prior art with regard to an assessment of the availability of the system.

[0010] A LiDAR system according to the invention comprises a transmitter unit configured to emit electromagnetic radiation directed into the environment of the LiDAR system; a receiver unit configured to detect a portion of the electromagnetic radiation emitted by the transmitter unit that is backscattered from the environment of the LiDAR system into the LiDAR system; an exit window configured to delimit the LiDAR system from the environment, at least in the direction of emission from the transmitter unit, wherein the electromagnetic radiation emitted by the transmitter unit is transmitted through the exit window into the environment; wherein the LiDAR system further comprises a contamination sensor configured to detect a portion of the electromagnetic radiation emitted by the transmitter unit that is backscattered from a surface of the exit window into the LiDAR system.Backscatter can occur from both the inside and outside (or both sides) of the exit window. In particular, this can involve a combination of a conventional LiDAR system with a camera acting as a contamination sensor, both positioned behind a common protective glass panel that serves as the exit window.

[0011] The electromagnetic radiation emitted by the transmitter unit for environmental sensing is therefore also used for sampling or illuminating contamination. The electromagnetic radiation scattered by the contamination can then be measured by the contamination sensor (radiation detector). In addition to pure contamination detection, the type and severity of the contamination can also be approximated by appropriate evaluation of the sensor data. Preferably, the transmitter unit has a defined beam axis for direction-dependent sensory sensing of the LiDAR system's surroundings. The direction of the beam axis is preferably variable relative to a surface of the exit window (especially in scanning or rotating LiDAR systems).

[0012] Preferably, a LiDAR system is a hermetically sealed structure with a housing, wherein the radiation-relevant components of the LiDAR system are arranged within the housing, and the electromagnetic radiation emitted by the system interacts with the environment to be detected outside the housing. A portion of the electromagnetic radiation emitted by the transmitting unit that is backscattered from the environment of the LiDAR system into the housing can then be detected by the receiving unit. The housing thus separates an interior from an exterior, with the exit and re-entry of the electromagnetic radiation preferably occurring via an exit window that is transparent to the electromagnetic radiation.

[0013] The purpose of such an exit window is to physically and structurally separate the LiDAR system from its surroundings, i.e., the outside environment, at least in the direction of transmission from the transmitter unit. The exit window therefore has an inner and an outer surface with corresponding surfaces, with the outer surface, open to the environment, being particularly susceptible to environmental contamination. In particular, surface deposits of dirt particles (e.g., dust, insects, leaves) or water (e.g., raindrops or snow) can negatively affect the transparency of the exit window. However, contamination can also occur on the inner surface of the exit window, so the entire exit window should preferably be monitored on both the inner and outer sides.

[0014] A portion of the electromagnetic radiation emitted by the transmitting unit, backscattered from a surface of the exit window into the LiDAR system, can be detected by the contamination sensor. For this purpose, the sensor is preferably positioned within the LiDAR system (for example, inside a housing) such that this radiation is backscattered directly from a surface of the outer window towards the sensor. Alternatively, the sensor can be positioned such that backscattering of this radiation occurs preferably from contaminants deposited on the surface. Backscattering from a surface of the exit window means that the scattering occurs either directly at the surface or through a deposit (contaminant) located on the surface. This deposit can be located on either the inner or outer surface of the exit window. Advantages of the invention

[0015] The LiDAR system according to the invention has the advantage that it can, in particular, determine the degree of contamination (for example, particles, water, snow, ice, oils, solids, liquids, transparent and non-transparent contaminants) of optically transparent (i.e., transparent) materials used to cover a 3D sensor (LiDAR) for the radiation emitted by the LiDAR system. This allows the availability of the 3D sensor to be monitored and ensured.

[0016] The core of the invention is the detection of contamination or particles of any kind on the exit window of an optoelectronic 3D sensor. Preferably, this can be a LiDAR system with a macro or micro scanner, or a solid-state system. A LiDAR system according to the invention allows for continuous monitoring of the exit window's condition. A small installation volume and low weight are particularly advantageous, since the 3D sensor's radiation source is used, eliminating the need for an additional radiation source within the system. This also prevents interference from additional light sources. Furthermore, it allows for minimal requirements on the electronics used.

[0017] Depending on the design of the contamination sensor, it is possible to precisely locate the contamination and determine its impact or intensity. Particularly with macro and micro scanners, knowing the current rotor or mirror position allows for exact localization of the contamination. The sensor principle for detecting contamination can also be used with curved or geometrically complex exit windows (for example, so-called freeform or curved windows).

[0018] Preferably, a LiDAR system according to the invention comprises an evaluation means configured to detect contamination of the exit window from an increase in the intensity of the electromagnetic radiation detected at the contamination sensor or from a decrease in the intensity of the specular Fresnel reflection of the electromagnetic radiation at the exit window. In particular, the amount of backscattered electromagnetic radiation at the contamination sensor or the loss of intensity in the specular reflection of the emitted electromagnetic radiation (caused, for example, by Fresnel reflections at the cover glass) can be measured. If there is no contamination on the exit window, typically only specular reflection occurs.In the event of contamination, the light is scattered over a wide angular range, thereby reducing the intensity of specular reflection and, in particular, scattering light even in previously unilluminated areas within the LiDAR system. Therefore, a wide variety of installation locations can be used for the contamination sensor.

[0019] Preferably, a multitude of contamination sensors are arranged at different positions within the LiDAR system. This enables the detection, at various angles, of components of the electromagnetic radiation emitted by the transmitter unit that are backscattered from the surface of the exit window into the LiDAR system (for example, to determine an "angle-resolved" scattering distribution). The multitude of contamination sensors can be configured, in particular, for the redundant detection of contamination across the entire surface area of ​​the exit window relevant for environmental perception. Furthermore, in a rotating system, the expected Fresnel reflection is usually known for each position of the rotor (which can, in principle, be read out using angle coding). Therefore, any deviation from this can indicate contamination and / or damage to the exit window.In the case of a solid-state LiDAR, where the rotor position cannot be read out, the spatial localization of a contamination can also be evaluated via an imaging optic on the detector.

[0020] Preferably, a LiDAR system according to the invention is biaxially or coaxially configured. Biaxial here means that the optical paths of the electromagnetic radiation emitted by the transmitting unit and detected by the receiving unit differ from one another; thus, the optical paths in the direction of a scattering center in the environment are not coincident. In a coaxial LiDAR system, on the other hand, the optical paths are coincident, meaning that emitted and detected radiation propagate at the same propagation angle.

[0021] Preferably, the transmitter and receiver units of the LiDAR system can be arranged side by side or one above the other. A laterally and vertically offset arrangement of these two components is also preferred.

[0022] Preferably, a LiDAR system according to the invention is a rigid or a rotating scanning system. A rigid LiDAR system is understood to be an arrangement in which the spatial orientation between the transmitter unit, receiver unit, and exit window is static and time-invariant. The area of ​​the exit window detected by the electromagnetic radiation emitted by the transmitter unit is therefore constant. In a rotating scanning system, the spatial orientation between the transmitter unit, receiver unit, and exit window varies over time; in particular, the transmitter unit and receiver unit can rotate about a fixed axis of rotation (in a specific plane of rotation). As a result, these components also change their spatial orientation relative to the exit window, meaning that different areas of the exit window are always detected by the electromagnetic radiation emitted by the transmitter unit.

[0023] In the case of a rotating system, a specific portion of the exit window can be scanned for contamination with the electromagnetic radiation emitted by the transmitter unit along the direction of rotation with each shot (in the case of a pulsed system). This allows a complete picture of the degree of contamination to be obtained. In the case of a stationary system, however, the same area of ​​the exit window is always scanned for contamination.

[0024] Preferably, a portion of the electromagnetic radiation emitted by the transmitting unit, backscattered from a surface of the exit window into the LiDAR system, is imaged onto the contamination sensor via imaging optics. The imaging optics enable a more precise spatial resolution with respect to the position and size of any contamination deposited on the exit window. Furthermore, by focusing the radiation onto a smaller area of ​​the contamination sensor, the signal-to-noise ratio (SNR) for spatially resolved detectors can be increased, thus improving the reliability of contamination detection (particularly by reducing the number of illuminated pixels).

[0025] Preferably, the contamination sensor is a single diode, a 1D array detector, or a 2D array surface detector for detecting electromagnetic radiation. While a single diode can only register the electromagnetic radiation incident in a specific area and possibly determine its intensity, 1D and 2D detectors additionally allow for a spatial determination of the intensity levels present at the detector across its surface. In particular, a 2D array surface detector, in combination with upstream imaging optics, enables spatially resolved contamination detection on the surface of the exit window.

[0026] Preferably, the contamination sensor can be integrated into the receiver unit. This can particularly involve embodiments in which one or more of the aforementioned detector types are integrated into the housing of the receiver unit. However, preferably the contamination sensor can also be integrally formed by that area of ​​the receiver unit which is configured to detect a portion of the electromagnetic radiation emitted by the transmitting unit that is backscattered from the environment of the LiDAR system into the LiDAR system (radiation-sensitive area).In particular, the detection of a portion of the electromagnetic radiation emitted by the transmitting unit that is backscattered from the environment of the LiDAR system into the LiDAR system, and of a portion of the electromagnetic radiation emitted by the transmitting unit that is backscattered from a surface of the exit window into the LiDAR system, can also be carried out via a common detector element, i.e., via a common radiation-sensitive area, within the receiver unit.

[0027] Another aspect of the present invention relates to a method for detecting contamination in LiDAR systems, comprising the steps of: directed emission of electromagnetic radiation into the environment of the LiDAR system by a transmitter unit, wherein the electromagnetic radiation emitted by the transmitter unit is transmitted into the environment through an exit window which separates the LiDAR system from the environment at least in the direction of emission of the transmitter unit; detection of a portion of the electromagnetic radiation emitted by the transmitter unit that is backscattered into the LiDAR system from a surface of the exit window by a contamination sensor, wherein the contamination sensor is a single diode, a 1D array detector or a 2D array surface detector for detecting electromagnetic radiation and / or the contamination sensor is integrated into the receiver unit;and detection of contamination of the exit window by evaluating the detection of the contamination sensor. Preferably, prior to the step of directed electromagnetic radiation into the environment, a LiDAR system according to the invention as described in this application can be deployed.

[0028] Preferably, the detection of contamination of the exit window can be achieved by means of an evaluation system based on either an increase in the intensity of the electromagnetic radiation detected by the contamination sensor or a decrease in the intensity of the specular Fresnel reflection of the electromagnetic radiation at the exit window. In the first case, contamination can lead to the detection of an increased proportion of radiation directed towards the contamination sensor, thus increasing the measured radiation intensity. In the second case, the contamination sensor can be directly aligned with the specular Fresnel reflection, so that a corresponding decrease in intensity is registered in the event of contamination.

[0029] Preferably, the portions of the electromagnetic radiation emitted by the transmitting unit that are backscattered from a surface of the exit window into the LiDAR system are detected at various angles using a plurality of contamination sensors arranged at different positions within the LiDAR system. Preferably, an imaging optic can be used to visualize a portion of the electromagnetic radiation emitted by the transmitting unit that is backscattered from a surface of the exit window into the LiDAR system.

[0030] Advantageous embodiments of the invention are specified in the dependent claims and described in the description. Drawings

[0031] Exemplary embodiments of the invention are explained in more detail with reference to the drawings and the following description. The drawings show: Fig. 1 a schematic representation of a first embodiment of a LiDAR system according to the invention in top view, Fig. 2 a schematic representation of a second embodiment of a LiDAR system according to the invention in top view, and Fig. 3 A schematic representation of a third embodiment of a LiDAR system according to the invention in top view. Embodiments of the invention

[0032] In the Fig. Figure 1 shows a schematic top view of a first embodiment of a LiDAR system 100 according to the invention. This is, in particular, a rigid, coaxially constructed LiDAR system 100. In the sectional plane shown, the LiDAR system 100 is, by way of example, enclosed by a housing 52, wherein the electromagnetic radiation 12 emitted by the transmitting unit 10 is transmitted into the environment 60 through an exit window 30 integrated into the housing 52.

[0033] The LiDAR system 100 shown comprises a transmitter 10 configured to emit electromagnetic radiation 12 directed into the environment 60 of the LiDAR system 100; a receiver 20 configured to detect a portion of the electromagnetic radiation 12 emitted by the transmitter 10 backscattered from the environment 60 of the LiDAR system 100 into the LiDAR system 100; and an exit window 30 configured to delimit the LiDAR system 100 from the environment 60 at least in the direction of emission from the transmitter 10, wherein the electromagnetic radiation 12 emitted by the transmitter 10 is transmitted through the exit window 30 into the environment 60. wherein the LiDAR system 100 further comprises a contamination sensor 40, configured to detect a proportion of the electromagnetic radiation 12 emitted by the transmitting unit 10 that is backscattered into the LiDAR system 10 at a surface 32, 33 of the exit window 30.

[0034] As an example, two contamination sensors 40, 40' are arranged at different positions within the LiDAR system 100, configured to detect components of the electromagnetic radiation 12 emitted by the transmitter unit 10 backscattered into the LiDAR system 10 at different angles from the surface 32, 34 of the exit window 30. In particular, a component of the electromagnetic radiation 12 emitted by the transmitter unit 10 backscattered into the LiDAR system 100 from a surface 32, 34 of the exit window 30 is imaged onto the contamination sensor 40 via an imaging optic 42.

[0035] This is therefore a coaxial design of an optoelectronic 3D sensor consisting of a transmitting unit 10 (for example, comprising beam-shaping optics and a light source) and a receiving unit 20 (for example, comprising receiving optics and a detector for the light). The aforementioned units 10 and 20 can be arranged in various configurations. The superposition of the optical axis of the receiving unit 20 to form a coaxial system can be achieved, in particular, via a partially transparent window (or an aperture with a hole or a slit), a mirror, or a prism.

[0036] Shown is a rigid system (such as a macro scanner, a micromirror-based coaxial system, or a coaxial flash LiDAR, where the entire field of view (FoV) is illuminated by a flash of light). However, the arrangement can also rotate clockwise or counterclockwise around a fixed axis of rotation (pointing out of the plane of the drawing). The transmitter unit 10 emits light, which, in the optoelectronic 3D sensor, is typically used to determine the distance and / or type of objects in the environment, either using a time-of-light (ToF) or frequency-modulated continuous-wave (FMCW) technique. The light backscattered from a target or object can then be detected and further processed by the receiver unit 20.

[0037] The light emitted by the transmitter 10 generally passes through an exit window 30 (which can have any geometry) before striking the object. There, the light can be scattered in different directions due to particles (contamination). This scattered light can be recorded by a contamination sensor 40. The contamination sensor 40 can be, in particular, a single diode (for example, an avalanche photodiode (APD), SPAD (single photon avalanche diode), etc.), a 1D array detector, or a 2D array surface detector (for example, a PIN diode, CCD, CMOS, APD, SPAD chip, or arrays thereof for the visible and / or near-infrared spectral range, or a bolometer for the far-infrared spectral range). The position of the contamination sensor 40 can be chosen arbitrarily. The choice of detector material (for example, silicon, InGaAs, etc.)The response time of the contamination sensor 40 depends primarily on the wavelength used in the transmitter unit 10. The contamination sensor 40 may also include optical filters, particularly to suppress background light (e.g., sunlight).

[0038] For precise localization of the contamination, a spatially resolved 1D or 2D detector can be used if the entire contamination sensor 40 is illuminated by a flash of light. If the illumination scans across the exit window 30 (spot illumination), the localization of the contamination can be determined by the position of the spot illumination or beam spots on the exit window 30, which is known at all times. In the case of a coaxial or biaxial system, the detector built into the receiver unit 20, which is sensitive to the emitted wavelength, can also be used to detect the contamination and thus provide information about the degree and location of the contamination. If the 3D sensor is a macro or micro scanner, the position of the contamination can additionally be read out by the direction of the transmitter unit 10 (rotor or micromirror position).

[0039] In the Fig. Figure 2 shows a schematic top view of a second embodiment of a LiDAR system according to the invention. This is, in particular, a rotating, biaxially constructed LiDAR system 100 (a rigid version is also possible). In the sectional plane shown, the LiDAR system 100 is, by way of example, enclosed by a circumferential exit window 30. Due to the rotation of the internal components of the LiDAR system 100 in the rotation plane 50 shown, the electromagnetic radiation 12 emitted by the transmitting unit 10 is also circumferential and can thus be transmitted from the exit window 30 into the surroundings 60 at any desired rotation angle.

[0040] The basic structure of the second embodiment shown nevertheless largely corresponds to that in Fig. The embodiment shown in Figure 1 is characterized by the different optical paths of the respective beam paths of the transmitting unit 10 and the receiver unit 20, and the resulting angular deviation between the incoming and outgoing radiation with respect to any object point in the environment 60.

[0041] This is a biaxial design of an optoelectronic 3D sensor (macro scanner) consisting of a transmitting unit 10 (for example, comprising beam-shaping optics and a light source) and a receiving unit 20 (for example, comprising receiving optics and a detector for the light). The aforementioned units 10 and 20 can be arranged in different configurations.

[0042] The arrangement can rotate clockwise or counterclockwise around a fixed axis of rotation (pointing out of the plane of the drawing) in a plane of rotation 50. The transmitter unit 10 emits light, which in the optoelectronic 3D sensor is typically used to determine the distance and / or type of objects in the environment, either using a Time-of-Light (ToF) or Frequency-Modulated Continuous-Wave (FMCW) technique. The light backscattered from a target or object can then be detected and further processed by the receiver unit 20.

[0043] The light emitted by the transmitter 10 generally passes through an exit window 30 (which can have any geometry) before reaching the object. There, the light can be scattered in different directions due to particles (contamination). This scattered light can be recorded by a contamination sensor 40. The contamination sensor 40 can be, in particular, a single diode (for example, an avalanche photodiode (APD), SPAD (single photon avalanche diode), etc.), a 1D array detector, or a 2D array surface detector (for example, a CCD chip for the visible and near-infrared spectral range, a bolometer for the far-infrared spectral range). The position of the contamination sensor 40 can be chosen arbitrarily, but it is preferably arranged in the vicinity of the transmitter 10 so that the backscattered light is directed onto the contamination sensor 40.The choice of detector material (e.g., silicon, InGaAs, etc.) for the contamination sensor 40 depends primarily on the wavelength used in the transmitter unit 10. The contamination sensor 40 may also include optical filters, particularly to suppress background light (e.g., sunlight).

[0044] For precise localization of the contamination, a 1D or 2D detector can be used if the entire contamination sensor 40 is illuminated by a flash of light. If the illumination scans across the exit window 30 (spot illumination), the localization of the contamination can be determined by the position of the spot illumination or beam spots on the exit window 30, which is known at all times. If the 3D sensor is a macro or micro scanner, the position of the contamination can also be read from the direction of the transmitting unit 10 (rotor or micromirror position).

[0045] In the Fig. Figure 3 shows a schematic top view of a third embodiment of a LiDAR system 100 according to the invention. The basic structure of the embodiment shown largely corresponds to that shown in Fig.The embodiment shown in Figure 1 is identical. The individual reference numerals and their assignments apply accordingly. The two embodiments differ only in the relative arrangement of the transmitting unit 10 and the receiving unit 20, with these components being arranged one above the other in the third embodiment shown. Such a stacked arrangement has the particular advantage that the required width is reduced by an alternative arrangement of the components, and thus the LiDAR system can be better fitted into laterally restricted installation spaces.

Claims

[1] LiDAR system (100), comprising: a) a transmitting unit (10) designed to emit electromagnetic radiation (12) directed into the environment (60) of the LiDAR system (100); b) a receiver unit (20) configured to detect a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered from the environment (60) of the LiDAR system (100) into the LiDAR system (100); c) an exit window (30) designed to delimit the LiDAR system (100) from the environment (60) at least in the direction of radiation from the transmitting unit (10), wherein the electromagnetic radiation (12) emitted by the transmitting unit (10) is transmitted through the exit window (30) into the environment (60); wherein d) the LiDAR system (100) further comprises a contamination sensor (40) configured to detect a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered into the LiDAR system (10) from a surface (32, 33) of the exit window (30), wherein a portion of the electromagnetic radiation (12) emitted by the transmitting unit (10) that is backscattered into the LiDAR system (100) from a surface (32, 34) of the exit window (30) is imaged onto the contamination sensor (40) via an imaging optic (42). [2] LiDAR system (100) according to claim 1, further comprising an evaluation means, configured to detect contamination of the exit window (30) from an increase in the intensity of the electromagnetic radiation (12) detected at the contamination sensor (40) or from a decrease in the intensity in the specular Fresnel reflection of the electromagnetic radiation (12) at the exit window (30). [3] LiDAR system (100) according to claim 1 or 2, wherein a plurality of contamination sensors (40) are arranged at different positions within the LiDAR system (100), configured to detect components of the electromagnetic radiation (12) emitted by the transmitting unit (10) backscattered at different angles on a surface (32, 34) of the exit window (30) into the LiDAR system (100). [4] LiDAR system (100) according to any of the preceding claims, wherein the LiDAR system (100) is biaxial or coaxial. [5] LiDAR system (100) according to any of the preceding claims, wherein the LiDAR system (100) is a rigid or a rotating scanning system. [6] LiDAR system (100) according to one of the preceding claims, wherein the contamination sensor (40) is a single diode, a 1D array detector or a 2D array surface detector for detecting electromagnetic radiation and / or the contamination sensor (40) is integrated into the receiver unit (20). [7] Method for detecting contamination in LiDAR systems (100), comprising the steps: a) directed emission of electromagnetic radiation (12) into the environment of the LiDAR system (100) by a transmitting unit (10), wherein the electromagnetic radiation (12) emitted by the transmitting unit (10) is transmitted into the environment (60) through an exit window (30) which separates the LiDAR system (100) from the environment (60) at least in the direction of emission of the transmitting unit (10); b) Detection of a fraction of the electromagnetic radiation (12) emitted by the transmitting unit (10) backscattered at a surface (32, 34) of the exit window (30) into the LiDAR system (100) by a contamination sensor (40), wherein the contamination sensor (40) is a single diode, a 1D array detector or a 2D array surface detector for the detection of electromagnetic radiation and / or the contamination sensor (40) is integrated into the receiver unit (20); c) Determination of contamination of the outlet window (30) by evaluating the detection of the contamination sensor (40). [8] Method according to claim 7, wherein a detection of contamination of the outlet window (30) is carried out by means of an evaluation from an increase in the intensity of the electromagnetic radiation (12) detected at the contamination sensor (40) or from a decrease in the intensity in the specular Fresnel reflection of the electromagnetic radiation (12) at the outlet window (30). [9] Method according to claim 7 or 8, wherein the portions of the electromagnetic radiation (12) emitted by the transmitting unit (10) that are backscattered at a surface (32, 34) of the exit window (30) into the LiDAR system (100) are detected at different angles via a plurality of contamination sensors (40) arranged at different positions within the LiDAR system (100).

Images