METHOD FOR DETECTING AN ACOUSTIC SIGNAL ON A VEHICLE

Abstract

Examples relate to a method (10) for detecting an acoustic signal (Sig) on ​​a vehicle (21), the method (10) comprising: using (11) a laser device (Lid', Lid'') of the vehicle for a laser microphone system to detect an acoustic vibration on a predetermined surface (21a, 41) of the vehicle (21); aligning (12) the laser device (Lid', Lid'') of the vehicle (21) onto the predetermined surface; sending (13) laser beams (L2) onto the predetermined surface by means of the aligned laser device (Lid', Lid''); and receiving (14) laser beams reflected from the predetermined surface by means of the aligned laser device (Lid', Lid'') in order to calculate the acoustic signal (Sig) from the reflected laser beams with the superimposed acoustic vibration.

Description

Technical field

[0001] Exemplary embodiments relate to a method for detecting an acoustic signal on a vehicle. Furthermore, a computer program for executing the proposed method is provided. Additionally, the use of a vehicle's lidar sensor as the laser transmitter and receiver unit of a laser microphone system is proposed. background

[0002] Modern motor vehicles use sensor systems for distance measurement, such as radar systems. In the field of distance measurement technologies, Light Detection and Ranging (Lidar) is also an established technique, similar in its operation to Radio Wave Detection and Ranging (Radar). Lidar systems use light beams, especially laser beams, to measure distances and are implemented as the preferred sensor technology by numerous vehicle manufacturers, particularly in the development of autonomous vehicles.

[0003] For optimal performance of these systems, an elevated and exposed mounting position is advantageous to ensure a comprehensive view of the vehicle's surroundings. However, this mounting position poses potential risks, as lidar systems are susceptible to contamination and damage. This vulnerability can impair the functionality and reliability of lidar-based sensors, necessitating protective mechanisms or cleaning systems to guarantee continuous and trouble-free operation. The development of such protection and maintenance solutions is therefore crucial for the integration and long-term functionality of lidar systems in autonomous vehicles.

[0004] It is known in the art to position lidar sensors behind the windshield to ensure both optimal positioning and protection. Furthermore, positioning them behind the windshield is particularly advantageous because the windshield's integrated cleaning system can be used. To maintain the lidar's performance, a special high-performance glass is used in its field of view, which is transparent to lidar beams (e.g., near-infrared beams). It is also known in the art that heat-insulating glass is often used in car windshields. This type of glass reflects, for example, near-infrared beams.

[0005] Lidar sensors can also be mounted on a vehicle's side mirror. Other sensors, such as external microphones, can also be mounted on the side mirror. However, due to their exposed position, such external microphones are susceptible to dirt or damage. A microphone positioned inside the vehicle (e.g., a diaphragm microphone) is inadequate for detecting acoustic signals outside the vehicle, especially low- to medium-volume signals. Therefore, according to established concepts, reliable detection of acoustic signals, particularly outside the vehicle, can be challenging. Summary

[0006] The purpose of the present disclosure is to provide improved concepts for capturing acoustic signals on a vehicle, in particular avoiding the shortcomings of using conventional condenser microphones on the outside of the vehicle.

[0007] This problem is solved according to the subject matter of the independent claims. Further advantageous embodiments are described in the dependent claims, the following description, and in conjunction with the figures.

[0008] Accordingly, a method for detecting an acoustic signal on a vehicle is proposed. The method comprises the steps of using a laser device on the vehicle for a laser microphone system to detect an acoustic vibration on a predetermined surface of the vehicle, and aligning the vehicle's laser device with the predetermined surface. Furthermore, laser beams are sent onto the predetermined surface by means of the aligned laser device, and reflected laser beams are received by means of the aligned laser device in order to calculate the acoustic signal from the reflected laser beams with the superimposed acoustic vibration.

[0009] The detection of the acoustic signal is thus based on the principle of a laser microphone. This method exploits the fact that, when the laser beams are reflected off the scanned, predetermined surface, the acoustic signal is modulated due to the oscillating movement (acoustic excitation) of the predetermined surface.

[0010] The proposed method advantageously utilizes the fact that many premium vehicles already have laser sensors installed for tasks such as distance measurement (Lidar technology). These laser sensors are sometimes positioned and / or oriented in such a way that they can be efficiently used for microphone operation in addition to distance measurement or similar driving functions, for example, alternately or simultaneously. Unlike conventional condenser microphones, a laser sensor can also be installed inside the vehicle to detect an acoustic signal outside the vehicle, since, for example, a vehicle window vibrates on both sides (both inside and outside) even when acoustically excited from one side (e.g., from the outside). Positioning the component within the vehicle, thus protecting it, results in less stress on the component compared to externally mounted components and is therefore subject to less wear.

[0011] For example, the laser device includes a lidar sensor in a vehicle's exterior mirror, the exterior mirror being aligned such that the lidar sensor is directed at the predetermined surface. Advantageously, the exterior mirror is usually foldable, and the lidar sensor can be positioned so that it is aligned with the predetermined surface when folded. This predetermined surface is, in particular, made of a material that reflects the laser beams. The angle of the lidar sensor to the predetermined surface in the aligned position is selected such that the reflected laser beam is at least partially reflected back to the lidar sensor.

[0012] For example, it is envisaged that a side window of the vehicle is used as the predetermined surface, with the exterior mirror in a folded position so that the lidar sensor is directed towards the side window. This can have the advantage that acoustic signals spoken towards the side window (e.g., when a user of the vehicle is standing in front of the door) can be recorded with particularly low interference and high signal strength.

[0013] In other words, an operating procedure is proposed for an electrically folding exterior mirror that also incorporates a lidar sensor. In normal operating mode (e.g., driving), the mirror functions as a side mirror and as a carrier for the lidar sensor to support autonomous driving functions, for example. In stationary mode, the mirror folds in such a way that the lidar sensor can scan the side window. In this mode (e.g., microphone operation), the lidar sensor is used to pick up acoustic signals emitted (e.g., spoken) by a person inside, outside, or next to the vehicle. This allows voice commands, such as those for unlocking the vehicle, to be processed while the vehicle is stationary.

[0014] According to a further embodiment of the method, the laser device comprises a lidar sensor (e.g., a front lidar sensor) mounted on the windshield of the vehicle. The lidar sensor mounted on the windshield is aligned such that it points towards a predetermined surface, which is a reflective area of ​​the windshield for the laser beams. For this purpose, the lidar sensor can be aligned on or behind the windshield. Due to geometric constraints, a small deflection range (e.g., less than 5°) of the lidar sensor may suffice for switching between the operating modes "driving mode" and "microphone mode." This allows, for example, the use of simple and energy-efficient actuators such as piezoelectric actuators for deflecting the lidar sensor.Accordingly, an adjustable front lidar sensor is proposed for a vehicle in order to carry out the procedure.

[0015] For a vehicle lidar system to function, a small section of the windshield is typically designed to be transparent to laser beams, while the remaining area reflects them more strongly. For example, the lidar sensor mounted on the windshield for a laser microphone mode is typically aligned with the more reflective area, while the lidar sensor for a driving function mode is aligned with a more transparent area. This allows the microphone function to be available, for instance, when the vehicle is stationary or lidar-based driving functions are deactivated.

[0016] Alternatively, for example, the lidar sensor mounted on the vehicle's windshield can be aligned (e.g., with a single alignment) so that the emitted laser beam only partially hits the reflective (e.g., more reflective) area of ​​the windshield and partially hits an area more transparent to laser beams. This advantageously allows, for example, the lidar sensor to operate simultaneously for driving functions and as a laser microphone. Furthermore, actuators for situational alignment of the lidar sensor can be omitted.

[0017] For example, the lidar sensor is designed so that less than 10% (or less than 5% or less than 1%) of the emitted laser beam hits the area of ​​the windshield that reflects laser beams. This small portion of the laser beam directed towards the more reflective area may be sufficient to enable the microphone function, while the laser beam emitted through the more transparent area still has enough power to reliably perform driving functions such as lidar-based distance measurement.

[0018] Another aspect concerns a computer program product or non-volatile storage medium containing program code to execute the procedure described above or below, when the computer program is run on a processor, a computer, or programmable hardware. Such a program can advantageously be run on an on-board computer or, alternatively, on a backend (e.g., a server connected to the vehicle or a cloud service) to execute the proposed procedure and detect the acoustic signal.

[0019] Another aspect concerns the use of a vehicle's lidar sensor as the laser transmitter and laser receiver unit of a laser microphone system.

[0020] For example, it is intended that a laser beam from the lidar sensor is directed at a window of the vehicle in order to detect an acoustic signal transmitted to the window of the vehicle.

[0021] The disclosed concept advantageously utilizes the fact that lidar sensors are already installed in vehicles, which can provide additional vehicle functionality in microphone mode without requiring the installation of further components. This increases cost and resource efficiency. Character description

[0022] Examples of implementation are explained in more detail below with reference to the accompanying figures. These show: Fig. 1. A flowchart of a procedure for detecting an acoustic signal on a vehicle; Fig. 2 a schematic representation of an adjustable side mirror in a first position for driving operation and a second position for microphone operation; Fig. 3 a schematic representation of the use of a side mirror lidar for scanning a vehicle side window; and Fig. 4 A schematic representation of the use of a front lidar for scanning a vehicle windshield. Description

[0023] Several embodiments are now described in more detail with reference to the accompanying drawings, which illustrate some of these embodiments. For clarity, the thickness dimensions of lines, layers, and / or regions may be exaggerated in the figures. In the following description of the accompanying figures, which only show some exemplary embodiments, the same reference numerals may denote identical or comparable components.

[0024] An element described as "connected" or "coupled" to another element may be directly connected or coupled to that other element, or interposed elements may be present. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meanings that a person skilled in the art in the field to which the embodiments belong would associate with them.

[0025] Electrically folding exterior mirrors are now standard in many modern vehicles. The mirrors can be folded in when parking to prevent damage, for example. The technology behind them is relatively simple: an electric motor folds or rotates the mirror. It is also well known that exterior mirrors are increasingly being equipped with more and more actuators and sensors. These include warning lights, electric mirror adjustment, automatic dimming to reduce glare, and the integration of complex sensors such as lidar sensors. Lidar sensors in exterior mirrors are particularly advantageous because they can monitor the areas to the side of the vehicle, such as blind spots.

[0026] Laser microphones are also well-known. A laser microphone is a technology that enables the detection of sound waves by analyzing vibrations on a surface, such as a glass pane. It uses a laser beam directed at a surface, which detects the vibrations caused by sound waves. These vibrations are then converted into sound waves and can be used to record speech.

[0027] Recording speech outside a vehicle presents a technical challenge, as traditional microphones (e.g., those with diaphragms) require complex protection. Furthermore, microphones mounted on the vehicle's exterior can fail very quickly, potentially leading to high maintenance and repair costs. Currently, there are few methods that allow for acoustic recording of people outside the vehicle without installing complex new technology inside or on the vehicle. Mounting microphones on the exterior of vehicles, particularly on the windows, poses a number of technical challenges. First, the microphones must be designed to withstand environmental influences such as wind, rain, snow, and extreme temperatures. Wind noise, for example, can significantly impair audio quality, making effective wind noise suppression essential.Furthermore, the microphones must be positioned in such a way that they do not negatively affect the vehicle's aerodynamics and do not create additional wind resistance that could increase fuel consumption. In addition, installing extra sensors such as microphones is technically very complex and expensive. Therefore, innovative technical solutions are needed to reliably and with high quality record acoustic signals outside the vehicle using existing sensors.

[0028] Fig. Figure 1 shows a flowchart of a method 10 for detecting an acoustic signal on a vehicle. The method 10 comprises using 11 a laser device of the vehicle for a laser microphone system to detect an acoustic vibration on a predetermined surface of the vehicle; aligning 12 the laser device of the vehicle with the predetermined surface; transmitting 13 laser beams to the predetermined surface by means of the aligned laser device; and receiving 14 laser beams reflected from the predetermined surface by means of the aligned laser device in order to calculate the acoustic signal from the reflected laser beams with the superimposed acoustic vibration.

[0029] The described method 10 can advantageously enable the provision of a laser microphone system using a vehicle lidar, so that acoustic signals on the vehicle, e.g., on vehicle windows, can be detected using existing sensors. In particular, conventional microphones, which e.g. use diaphragms, can be dispensed with.

[0030] Fig. Figure 2 shows a schematic representation 20 of an adjustable side mirror with a lidar sensor Lid' in a first position Pos_1 for driving operation and a second position Pos_2 for microphone operation. The side mirror is positioned on a side window 21a of a vehicle 21. In the first position Pos_1, the lidar sensor Lid' can scan the area behind the vehicle using a first laser beam L1, e.g., to detect overtaking vehicles.

[0031] In the second position Pos_2 (e.g., folded in parked position), the lidar sensor Lid' can scan a window area directed towards the side window using a second laser beam L2. This enables microphone operation, as laser beams reflected from the side window can in turn be received by the lidar sensor Lid' of the side mirror.

[0032] Further details and aspects are mentioned in connection with the exemplary embodiments described above or below. The in Fig. The embodiment shown in section 2 may have one or more optional additional features corresponding to one or more aspects that are related to the proposed concept or to one or more of the above (e.g. Fig. 1) or below (e.g. Fig. 3-4) described embodiments are mentioned.

[0033] Fig. Figure 3 shows a schematic representation 30 of the use of a side mirror lidar Lid' for scanning the vehicle side window 21a. For this purpose, the side mirror of the vehicle 21 is folded in so that the side mirror lidar Lid' is aligned with the vehicle side window 21a. This corresponds to the second position Pos_2 of the side mirror for microphone operation according to Fig. 2.

[0034] A user N can speak in the microphone operation thus enabled, so that an acoustic signal Sig in the direction of speech 31 hits the side window 21a.

[0035] When parked, the mirror is folded in such a way that it is protected from damage and the integrated lidar lid is aligned with the side window 21a. The lidar lid is then adjusted to detect vibrations of the side window 21a, such as those caused by natural speech.

[0036] When an authorized person, e.g., user N, approaches vehicle 21, the lidar Lid' scans the side window 21a and thus detects the sound striking the side window 21a. In this way, the person's spoken words can be captured and processed by the vehicle system.

[0037] Further details and aspects are mentioned in connection with the exemplary embodiments described above or below. The in Fig. The embodiment shown in section 3 may have one or more optional additional features corresponding to one or more aspects that are related to the proposed concept or to one or more of the above (e.g. Fig. 1-2) or below (e.g. Fig. 4) described embodiments are mentioned.

[0038] Fig. Figure 4 shows a schematic representation 40 of the use of a front lidar Lid'' for scanning a vehicle windshield 41. The vehicle windshield 41 includes a small, more transparent section 41a, which is more transparent to laser beams than the rest of the vehicle windshield 41. Laser beams from the front lidar Lid'' can be sent and received through this more transparent section 41a, for example, to perform distance measurements to vehicles ahead (this can be referred to as "normal operation"). For this purpose, a first laser beam L1 can be sent from the vehicle through the more transparent section 41a.

[0039] Part of the disclosure concerns the aspect that acoustic signals outside the vehicle are recorded via a lidar sensor lid'' integrated in or behind the windscreen 41. The core idea of ​​this aspect is that in "normal operation," the lidar lid'' utilizes a field of view, e.g., the more transparent area 41a, which is highly transparent to the lidar lid'', and in "microphone operation," it targets an area that is opaque to near-infrared rays, thus reflecting them. In this way, a second lidar beam L2 is reflected by the windscreen 41 in "microphone operation" and can therefore acoustically scan it. The lidar lid'' can be designed to be pivotable, e.g., within a small angular range of more than 1° and / or less than 5°, to facilitate switching between operating modes.

[0040] A particular advantage of this concept is that no additional components are required. Lidar sensors in windshields already require a highly transparent viewing area to ensure the laser (first laser beam L1) maintains its performance. Since the rest of the windshield is typically made of heat-insulating glass, which reflects the laser (second lidar beam L2), implementing this concept only requires a new operating mode for the laser or lidar sensor.

[0041] An alternative embodiment involves a windshield (e.g., a section of a windshield) that is transparent to the lidar beams but coated in a small area to reflect the laser beam and thus capture the vibrations of the windshield. This embodiment has the additional technical advantage that the laser can be used simultaneously as a 3D measuring laser in normal operation and as a microphone. For this purpose, in addition to the normal field of view, a small additional area of ​​the windshield is scanned, reflecting the laser beams directly off the windshield. This enables microphone functionality even while driving.

[0042] Further details and aspects are mentioned in connection with the exemplary embodiments described above or below. The in Fig. The embodiment shown in section 4 may include one or more optional additional features corresponding to one or more aspects that are related to the proposed concept or to one or more of the above (e.g., Fig. 1-3) or the embodiments described below.

[0043] Examples include a multifunctional laser system in the windshield for providing a microphone mode, and a system and method for operating an electric exterior mirror for voice input via the side window.

Claims

[1] Method (10) for detecting an acoustic signal (Sig) on ​​a vehicle (21), the method (10) comprising: - Using (11) a laser device (Lid', Lid'') of the vehicle for a laser microphone system to detect an acoustic vibration at a predetermined surface (21a, 41) of the vehicle (21); - Aligning (12) the laser device (Lid', Lid'') of the vehicle (21) with the predetermined surface; - Sending (13) laser beams (L2) onto the predetermined surface by means of the aligned laser device (Lid', Lid''); and - Receiving (14) laser beams reflected from the predetermined surface by means of the aligned laser device (Lid', Lid'') in order to calculate the acoustic signal (Sig) from the reflected laser beams with the modulated acoustic vibration. [2] Method (10) according to claim 1, wherein the laser device (Lid', Lid'') comprises a lidar sensor (Lid') in an external mirror of the vehicle (21), wherein the exterior mirror is aligned (12) such that the lidar sensor (Lid') of the exterior mirror is directed towards the predetermined surface (21a). [3] Method (10) according to claim 2, wherein a side window (21a) of the vehicle (21) is used as the predetermined surface, wherein the exterior mirror in a folded state (Pos_2) is aligned such that the lidar sensor (Lid') is directed towards the side window (21a) of the vehicle (21). [4] Method (10) according to claim 1, wherein the laser device (Lid', Lid'') comprises a lidar sensor (Lid'') arranged on a windscreen (41) of the vehicle (21), wherein the lidar sensor (Lid'') arranged on the windscreen (41) of the vehicle (21) is aligned such that the lidar sensor (Lid'') is directed towards the predetermined surface (41), wherein the predetermined surface (41) is a region of the front window (41) that reflects the laser beams. [5] Method (10) according to claim 4, wherein the lidar sensor (Lid'') arranged on the windshield (41) of the vehicle (21) is aligned to the reflective area of ​​the windshield (41) for a laser microphone mode, wherein the lidar sensor (Lid'') arranged on the windscreen (41) of the vehicle (21) is directed towards a more transparent area (41a) of the windscreen (41) for a lidar mode for a driving function of the vehicle (21). [6] Method (10) according to claim 4, wherein the lidar sensor (Lid'') arranged on the windscreen (41) of the vehicle (21) is aligned (12) such that the transmitted laser beam (L1) only partially hits the reflective area of ​​the windscreen (41) and partially hits an area (41a) of the windscreen (41) that is more transparent to the laser beams (L1). [7] Method (10) according to claim 6, wherein the lidar sensor (Lid', Lid'') is aligned such that the transmitted laser beam (L1, L2) hits the area of ​​the front window (41) reflecting the laser beams to a proportion of less than 10%. [8] Computer program product or non-volatile storage medium containing program code for performing the method (10) according to any of the preceding claims when the computer program is executed on a processor, a computer, or programmable hardware. [9] Using a vehicle lidar sensor (Lid', Lid'') (21) as a laser transmitter and laser receiver of a laser microphone system. [10] Using the lidar sensor (Lid', Lid'') according to claim 9, wherein a laser beam (L2) of the lidar sensor (Lid', Lid'') is directed at a disc (41) of the vehicle (21) to detect an acoustic signal (Sig) transmitted to the disc (41) of the vehicle (21).

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