GB2599387A

GB2599387A - A sound detection device for a motor vehicle for detecting a sound in the surroundings of the motor vehicle, as well as a corresponding detection method

Info

Publication number: GB2599387A
Application number: GB2015451.4A
Authority: GB
Inventors: Tharpe Christopher
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2022-04-06
Also published as: GB202015451D0

Abstract

The sound detection device 12 comprises a laser device 28 for sending a laser beam 30 inside the window glass 14 of the motor vehicle 10, wherein the laser beam 30 is influenced by the sound waves 20. The laser beam is retained within the window glass by total internal reflection. A capturing device 24 is configured for capturing the deflected laser beam 30 as the physical parameter, which is deflected inside the window 14, and the electronic computing device 26 is configured to analyze the influenced and deflected laser beam 30.

Description

A SOUND DETECTION DEVICE FOR A MOTOR VEHICLE FOR DETECTING A SOUND IN THE SURROUNDINGS OF THE MOTOR VEHICLE, AS WELL AS A CORRESPONDING DETECTION METHOD

FIELD OF THE INVENTION

[0001] The invention relates to the field of automobiles. More specifically, the invention relates to a sound detection device for a motor vehicle for detecting a sound in the surroundings of the motor vehicle, as well as to a corresponding detection method.

BACKGROUND INFORMATION

[0002] A motor vehicle might use external sound detection for responding to commands issued by a user of the motor vehicle, interpreting responses from a sonar, or sensing the state of the environment based on ambient sound, for example, a loud crash might indicate an accident nearby, or a horn might indicate the presence of another vehicle that should be avoided.

[0003] Traditionally, sound is detected by using a microphone operating on electromagnetic principles. To operate properly, the microphone must be exposed to the surroundings.

[0004] CN 10589996 A discloses an unmanned aerial vehicle to cancel background noise from audio data collected by the unmanned aerial vehicle. The unmanned aerial vehicle is provided with one or more background microphones in proximity of one or more background noise-producing components. The unmanned aerial vehicle is also provided with one or more audio source collecting microphones. The audio data collected by the background microphones may be used to reduce or cancel interfering background noise from the audio signal detected by the audio source collecting microphone. The target audio may be captured or recorded with little or no background noise.

[0005] According to the state of the art, the microphone, which is exposed to the surroundings, is vulnerable to environmental conditions, for example, it might become clogged with mud or ice, or it might be shorted out through exposure to water, or it might corrode over time to the point that it is no longer functional. Therefore, there is a need in the art for a more efficient system and/or method of sound detection for a motor vehicle.

SUMMARY OF THE INVENTION

[0006] It is an object of the invention to provide a sound detection device as well as a corresponding detection method, by which more robust sound detection may be realized.

[0007] This object is solved by a sound detection device as well as a corresponding detection method according to the independent claims. Advantageous embodiments are presented in the dependent claims.

[0008] One aspect of the invention relates to a sound detection device for a motor vehicle for detecting a sound in the surroundings of the motor vehicle, comprising a capturing device for capturing a physical parameter depending on sound waves of the sound and comprising an electronic computing device for analyzing the physical parameter.

[0009] In an embodiment the sound detection device comprises a laser device for sending a laser beam inside a window of the motor vehicle, wherein the laser beam is influenced by the sound waves, and the capturing device is configured for capturing the deflected laser beam as the physical parameter, which is deflected inside the window, and the electronic computing device is configured to analyze the influenced and deflected laser beam.

[0010] In an embodiment the electronic components of the sound detection device are contained inside the motor vehicle and are not exposed to the surroundings. According to the embodiment that uses total internal reflection of the laser beam, there may be little or no chance for a user of the motor vehicle or a person outside the motor vehicle to be exposed to the laser. Thereby danger of laser eye damage is minimized. In using an internally reflected laser there is less chance that the laser beam could be interfered with. For example, dust particles would not interrupt the beam.

[0011] In an embodiment the capturing device is a photo diode and/or a phototransistor and/or a photovoltaic cell.

[0012] In another embodiment the electronic computing device is configured to produce a converted sound and/or a storable electronic file and/or a sound signal for another device of the motor vehicle depending on the influenced and deflected laser beam.

[0013] In another embodiment the laser beam is totally internally reflected off a boundary between the window and the surroundings.

[0014] Another aspect of the invention relates to a motor vehicle with a sound detection device according to the preceding aspect.

[0015] A further aspect of the invention relates to a method for detecting a sound in the surroundings of the motor vehicle by a sound detection device, wherein a physical parameter of sound waves of the sound is captured by a capturing device and the physical parameter is analyzed by an electronic computing device of the sound detection device.

[0016] In an embodiment a laser beam of a laser device of the sound detection device is sent inside a window of the motor vehicle, wherein the laser beam is influenced by the sound waves and the deflected laser beam, which is deflected inside the window, is captured by the capturing device as the physical parameter and the influenced and deflected laser beam is analyzed by the electronic computing device.

[0017] Advantageous embodiments of the sound detection device are to be regarded as advantageous embodiments of the motor vehicle as well as of the corresponding detection method. The sound detection device as well as the motor vehicle therefore comprises means for performing the method.

[0018] Further advantages, features, and details of the invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in any other combination or taken alone without leaving the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The novel features and characteristics of the disclosure are set forth in the independent claims. The accompanying drawings, which are incorporated in and constitute part of this disclosure, illustrate exemplary embodiments and together with the description, serve to explain the disclosed principles. In the figures, the same reference signs are used throughout the figures to refer to identical features and components. Some embodiments of the system and/or methods in accordance with embodiments of the present subject-matter are now described below, by way of example only, and with reference to the accompanying figures.

[0020] The drawings show in: [0021] Fig. 1 a schematic view of an embodiment of a motor vehicle with an embodiment of a sound detection device; [0022] Fig. 2 a schematic view of an embodiment of the sound detection device; [0023] Fig. 3 a schematic view of another embodiment of a sound detection device; and [0024] Fig. 4 another schematic view of an embodiment of the sound detection device.

[0025] In the figures same elements or elements having the same function are indicated by the same reference signs.

DETAILED DESCRIPTION

[0026] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0027] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0028] The terms "comprises'', "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion so that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by "comprises" or "comprise" does not or do not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0029] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0030] Fig. 1 shows in a schematic view a motor vehicle 10 with an embodiment of a sound detection device 12. In the lower part of Fig. 1 the motor vehicle 10 is shown from the side and in the upper part of Fig. 1 the motor vehicle 10 is shown in a schematically top view. In particular, in the upper part of Fig. 1 just a window 14 of the motor vehicle 10 is shown. Furthermore, an A-pillar 16 and a B-pillar 18 are shown.

[0031] The sound detection device 12 for the motor vehicle 10 is configured for detecting a sound 20 in the surroundings 22 of the motor vehicle 10. The sound detection device 12 comprises a capturing device 24 for capturing a physical parameter of sound waves of the sound 20 and comprises an electronic computing device 26 for analyzing the captured sound waves.

[0032] In an embodiment the sound detection device 10 comprises a laser device 28 for sending a laser beam 30 inside the window 14 of the motor vehicle 10, wherein the laser beam 30 is influenced by the sound waves, and the capturing device 24 is configured for capturing the deflected laser beam 30 as the physical parameter, which is deflected inside the window 14, and the electronic computing device 26 is configured to analyze the influenced and deflected laser beam 30.

[0033] According to an embodiment the electronic computing device 26 is configured to produce a converted sound and/or a storable electronic file and/or a sound signal for another device of the motor vehicle 10 depending on the influenced and deflected laser beam 30.

[0034] In another embodiment the laser beam 30 is totally internally reflected off of a boundary 32 between the window 14 and the surroundings 22.

[0035] In particular, the sound 20 is transmitted by waves traveling through a medium. The waves are variations in pressure over time. This variation in pressure may be registered with, for example, a membrane, such as an eardrum or a tympanic membrane. The variation in pressure causes the membrane to vibrate in relation to the pressure variation. A laser reflecting off of a surface may be used to measure vibration of that surface. The motion of the surface will cause the endpoint of the reflected laser beam 30 to vary in relation to the amount of vibration.

[0036] Different transparent materials may have different indices of refraction which are related to the speed of light in those materials. If two different materials are placed together and there is sufficient difference in their indices of refraction, a light wave incident to a boundary 32 between those materials beyond a certain angle can be reflected completely within one of the materials. This is called "total internal reflection".

[0037] The laser beam 30 directed through one edge of the vehicle window 14, totally internally reflected off of the boundary 32 between the surface of the window 14 and the external air, in particular the surroundings 22, and then detected by the capturing device 24 at another edge of the window 14, are used to measure the vibration of the window 14 caused by the sound waves external to the motor vehicle 10. These vibrations may then be interpreted by the electronic computing device 26 to reproduce or store the externally generated sound 20. The window 14 would then basically serve as a tympanic membrane. This would allow effectively having a microphone outside the motor vehicle 10 without actually having a microphone outside the motor vehicle 10.

[0038] According to an embodiment sound waves are generated by a source external to the motor vehicle 10. The sound waves come into contact with the window 14. The window 14 vibrates in response to the incident sound waves, having an initial position before vibration begins, then having different positions during the course of the vibration. The laser device 28 produces the laser beam 30 that is shown through one edge of the window 14. The laser beam 30 is totally internally reflected off of the boundary 32 between the window 14 and the surroundings 22. The window 14 vibrates and its position changes in response to the sound waves, the position of the reflected laser beam 30 also varies. The capturing device 24 or a group of different capturing devices 24 are positioned at the endpoint of the reflected laser beam 30 and may convert the location of the reflected laser beam 30, or the frequency of its motion, into a signal. The signal may then be interpreted by the electronic computing device 26. The electronic computing device 26 may produce an output that might allow the signal to be converted back into sound, stored as an electronic file or used as an input for other processes of other devices of the motor vehicle 10.

[0039] In an embodiment the capturing device 24 is a photodiode and/or a phototransistor and/or photovoltaic cell.

[0040] With the following formulas decibel are converted into pressure: Lp = 20 log10(P / Pref), wherein Lp is the sound pressure in decibels, P is the pressure value equivalent to Lp, Pref is the reference pressure, and is the minimum pressure detectable by human hearing: Pref = 2 x 10-5 Pa (Pa = Pascals = Newtons / meter2) Solving for P: Lp / 20 = log10 (P1 Prof) A (Lp / 20) = RI Pref P = Pref x (10 A (Lp /20)) P = 2x10-5 * 10 A (60 / 20) P = 2x10-5 x 10000 P = 2x10-2 = 0.02 Pa = 0.02 N / m2 The formula for finding maximum deflection of a simply supported beam with a distributed load is Omax = 5w0L4 / 384E1 where Omax is the maximum deflection, wo is the load per unit length, L is the length of the simply supported beam, E is the modulus of elasticity and I is the moment of inertia. For a prototype of an acrylic sheet as the window 14: Wo = (0.02 N / m2)(0.3048 m) = 0.0061 N/m L, the length, is 12', in metric, 0.3048 m 1, the moment of inertia, for a rectangular cross section is: I = (b h3) /12 In this case, b is the width of the acrylic sheet and h is its thickness, in metric units: I = (0.3048 m) (0.00635 m)3 /12 = 6.5036 x 10-9 m4 E, the modulus of elasticity for acrylic is: E = 3.2 x 109 N / m2 Therefore: Omax = 5(0.0061)(0.3048)4 / ( (384)(2.6 x 109)(6.5036 x 10-9)) Omax = 2.623 x 10-4 / 6.493 x 103 Omax = 4.05429 x 10-8 m This a small value, a wavelength of visible light is in the range of 10'm. With such a small deflection, it might be necessary to use some type of interferometry to detect the vibration of the window 14, wherein some embodiments are shown in the Fig. 2, Fig. 3, and Fig. 4.

[0041] Fig. 2 shows another schematic view according to an embodiment of the sound detection device 12. According to the shown embodiment, the sound detection device 12 comprises a plurality of first-surface mirrors 34 as well as two beam splitters 36. The laser beam 30 is sent from the laser device 28 to a first beam splitter 36 and then to different first-surface mirrors 34, as shown in Fig. 2. This is avery small value of the deflection, a wavelength of visible light is in the range of 10-7 m. With such a small deflection, it is necessary to use some type of interferometry to detect the vibration of the window 14. With the embodiment shown in Fig. 2, the vibration may be detected.

[0042] Fig. 3 shows another embodiment of the detection device 12. According to the embodiment shown in Fig. 3 another possibility for dealing with deflection being smaller than the wavelength of light is shown, wherein the laser beam 30 is reflected inside the window 14 multiple times.

[0043] Fig. 4 shows another embodiment of the sound detection device 12 where the [0044] deflection being smaller than the wavelength of light is shown. It is shown that the laser beam 30 is reflected outside the window 14 by the two shown mirrors 34, which send the laser beam 30 through window 14 multiple times.

Reference Signs motor vehicle 12 sound detection device 14 window 16 A-pillar 18 B-pillar sound 22 surroundings 24 capturing device 26 electronic computing device 28 laser device laser beam 32 boundary 34 mirror 36 beam splitter

Claims

CLAIMS1. A sound detection device (12) for a motor vehicle (10) for detecting a sound (20) in the surroundings (22) of the motor vehicle (10), the sound detection device (12) comprising a capturing device (24) for capturing a physical parameter depending on sound waves of the sound (20) and comprising an electronic computing device (26) for analyzing the physical parameter, characterized in that the sound detection device (12) comprises a laser device (28) for sending a laser beam (30) inside a window (14) of the motor vehicle (10), wherein the laser beam (30) is influenced by the sound waves, and the capturing device (24) is configured for capturing the deflected laser beam (30) as the physical parameter, which is deflected inside the window (14), and the electronic computing device (26) is configured to analyze the influenced and deflected laser beam (30).
2. The sound detection device (12) according to claim 1, characterized in that the capturing device (24) is a photodiode and/or a phototransistor and/or photovoltaic cell.
3. The sound detection device (12) according to claim 1 or 2, characterized in that the electronic computing device (26) is configured to produce a converted sound and/or a storable electronic file and/or a sound signal for another device of the motor vehicle (10) depending on the influenced and deflected laser beam (30).
4. The sound detection device (12) according to any one of claims 1 to 3, characterized in that the laser beam (30) is totally internally reflected off a boundary (32) between the window (14) and the surroundings (22).
5. A method for detecting a sound (20) in the surroundings (22) of a motor vehicle (10) by a sound detection device (12), wherein a physical parameter depending on sound waves of the sound (29) is captured by a capturing device (24) and the physical parameter is analyzed by an electronic computing device (26) of the sound detection device (12), characterized in that a laser beam (30) of a laser device (28) of the sound detection device (12) is sent inside a window (14) of the motor vehicle (10), wherein the laser beam (30) is influenced by the sound waves, and the deflected laser beam (30), which is deflected inside the window (14), is captured by the capturing device (24) as the physical parameter and the influenced and deflected laser beam (30) is analyzed by the electronic computing device (26).