NOISE REDUCTION SYSTEM AND METHOD FOR ACTIVELY COMPENSATING BACKGROUND NOISES

Abstract

A noise reduction system (2) and a method for actively compensating background noises in a passenger transport area of a vehicle. Said system includes a control unit (8), at least one microphone (10), at least one sound generator (12) and a position detection unit for detecting a position and/or orientation of the head (16) of a user. The control unit (8) is coupled to the position detection unit on an input side, is configured to receive position data and to determine a position signal from the position data, and to generate an antinoise signal from the background noise signal and the position signal. The sound generator (12) is configured to generate antinoise from the antinoise signal such that, by superimposing the antinoise in a quiet zone (20a, 20b) within the passenger transport area, which antinoise is in phase opposition with the background noise, active reduction of the background noise is achieved. The position detection unit is a 3D camera arrangement (14).

Claims

1. A noise reduction system for actively compensating background noises in a passenger transport area of a vehicle, said system comprising: a control unit; at least one microphone for detecting a background noise; at least one sound generator for generating antinoise; and a position detection unit for detecting a position and/or orientation of a head of a user in the passenger transport area; wherein the control unit is coupled to the microphone on an input side and is configured to receive a background noise signal, wherein the control unit is coupled to the position detection unit on the input side, and is configured to receive position data and to determine a position signal from the position data, the position signal indicating the position and/or orientation of the head of the user relative to the position detection unit, wherein the control unit is configured to generate an antinoise signal from the background noise signal and the position signal, wherein the control unit is coupled to the sound generator on an output side and is configured to provide the antinoise signal, wherein the sound generator is configured to generate antinoise from the antinoise signal such that, by superimposing the antinoise in a quiet zone within the passenger transport area, which antinoise is in phase opposition with the background noise, active reduction of the background noise is achieved, and wherein the position detection unit is a 3D camera arrangement.

2. The noise reduction system according to claim 1, wherein the 3D camera arrangement forms a spatially enclosed structural unit together with the at least one microphone, the at least one sound generator and the control unit.

3. The noise reduction system according to claim 2, wherein the spatially enclosed structural unit is a headrest of a motor vehicle.

4. The noise reduction system according to claim 2, wherein the spatially enclosed structural unit comprises fastening means such that the spatially enclosed structural unit is mountable on a headrest of a motor vehicle.

5. The noise reduction system according to claim 4, wherein the spatially enclosed structural unit projects beyond the headrest on both sides in a horizontal direction or projects beyond the headrest in a vertical direction and at least the 3D camera arrangement is arranged in the portions projecting beyond the headrest.

6. The noise reduction system according to claim 1, wherein the 3D camera arrangement comprises at least one first and one second camera, and wherein a stereo base is oriented vertically between the first and the second camera.

7. The noise reduction system according to claim 1, wherein a plurality of microphones are provided for detecting the background noise.

8. The noise reduction system according to claim 7, wherein four microphones per quiet zone are provided.

9. The noise reduction system according to claim 1, wherein the control unit comprises a neural network which is configured to receive image data or an image data stream from the 3D camera arrangement as position data and to determine and output the position signal, which indicates the position and/or orientation of the head of the user relative to the position detection unit.

10. The noise reduction system according to claim 9, wherein the control unit comprises an FPGA and the neural network is implemented in the FPGA.

11. A method for actively compensating background noises in a passenger transport area of a vehicle, the method comprising: detecting a background noise with at least one microphone; converting the background noise into a background noise signal using the microphone; detecting position data using a position detection unit; determining, from the position data using the position detection unit, a position signal which indicates a position and/or orientation of head of a user in the passenger transport area relative to the position detection unit; generating an antinoise signal from the background noise signal and the position signal; and generating antinoise from the antinoise signal by a sound generator; wherein the antinoise is superimposed on the background noise so as to be in phase opposition therewith in a quiet zone within the passenger transport area such that active reduction of the background noise is achieved in the quiet zone, and wherein the position detection unit is a 3D camera arrangement, and 3D image data or a 3D image data stream is generated as the position data.

12. The method according to claim 11, wherein the position data is fed into a neural network and the neural network generates the position signal from the position data and outputs said position signal, which indicates the position and/or orientation of the head of the user relative to the position detection unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention is described below, without restricting the general idea of the invention, using exemplary embodiments with reference to the drawings, express reference being made to the drawings with regard to all details according to the invention that are not explained in greater detail in the text. In the following:

[0049] FIG. 1 shows a noise reduction system in a schematically simplified perspective view,

[0050] FIG. 2 shows another noise reduction system in a schematically simplified perspective view,

[0051] FIG. 3 shows said noise reduction system integrated in a headrest in another schematically simplified perspective view,

[0052] FIG. 4 shows a noise reduction system that can be mounted on a headrest in a schematically simplified front view, and

[0053] FIG. 5 shows said noise reduction system in a schematically simplified perspective view.

[0054] In the drawings, the same or similar elements and/or parts are provided with the same reference numbers in order to prevent the item from needing to be reintroduced.

DETAILED DESCRIPTION OF THE INVENTION

[0055] FIG. 1 shows a noise reduction system 2 for actively compensating background noises. The noise reduction system 2 is mounted in a passenger transport area of a vehicle, which is not shown as such. With regard to the vehicle, merely part of a driver's seat 4 having a headrest 6 attached thereto is shown in a schematic and simplified manner. The vehicle is, for example, a car, a truck or another utility vehicle. Said vehicle is, for example, a construction machine or agricultural machine.

[0056] The noise reduction system 2 comprises a control unit 8 and a plurality of microphones 10. A noise reduction system 2 having eight microphones 10 is shown by way of example. The microphones 10 are arranged on the upper and lower edge of the headrest 6 and integrated therein. Of the eight microphones 10, the microphones 10 provided on the lower edge of the headrest 6 are hidden, and only the microphones 10 provided on the upper edge of the headrest 6 are visible. The microphones 10 are used to detect a background noise.

[0057] The background noise is emitted by a noise source 25. A reference sensor 23 is located between the noise source 25 and the microphones 10, which reference sensor may also be a microphone. The reference sensor 23 is optional. The need for a reference sensor depends on whether the noise reduction system 2 is a feedforward system (with a reference sensor 23) or a feedback system (without a reference sensor 23). Instead of a microphone as the reference sensor 23, which directly measures the background noise emitted by the noise source 25, an acceleration sensor may also be provided, for example. An engine speed or other suitable parameter may also be fed into the system. Using the data from the acceleration sensor, the engine speed or another parameter, the background noise context of the vehicle can be deduced on the basis of a model. Said background noise context is used as the basis for the calculation of the antinoise signal instead of the background noises detected by a microphone used as the reference sensor 23. The reference sensor 23 couples its signal into the control unit 8 on the input side. In the case of a feedback system, the reference sensor 23 can be dispensed with.

[0058] Furthermore, the noise reduction system 2 comprises at least one sound generator 12. A system is shown which comprises two sound generators 12, which are loudspeakers, by way of example. The sound generators are used to generate antinoise. Furthermore, the noise reduction system 2 comprises a position detection unit for detecting a position and/or orientation of the head 16 of a schematically indicated user. The position detection unit is a 3D camera system 14. The user, who is the driver of the vehicle, for example, is located in a passenger transport area of the vehicle.

[0059] The control unit 8 is coupled to the eight microphones 10 on the input side. The microphones 10 detect the background noise, convert same into a background noise signal, and couple said signal into the control unit 8 on the input side. By virtue of the plurality of microphones 10, it is possible to provide a virtual sensor both for the right and for the left ear of the user, such that efficient noise reduction can be provided at the relevant ear of the user.

[0060] However, this requires the noise reduction system 2 to know the exact position of the ears of the user, more specifically the position of the exit of the auditory canal. The noise reduction system 2 comprises the position detection unit for this purpose. Said position detection unit generates position data in the form of 3D image data or a 3D image data stream. The 3D camera arrangement 14 comprises a first camera 18a and a second camera 18b. The position data is converted into a position signal in the processing unit 8, which signal indicates the position and/or orientation of the head 16 of the user relative to the 3D camera arrangement 14. Therefore, in other words, the position and/or orientation of the head 16 of the user relative to the 3D camera arrangement 14 is known. Since the 3D camera arrangement 14 is permanently installed in the vehicle, the spatial relationship between the sound generators 12 and the 3D camera arrangement 14 can be calibrated such that the control unit 8 can calculate an antinoise signal from the background noise and the position signal. For this purpose, the location of a virtual microphone 22a that is at least close to the entrance of the auditory canal of the user is calculated.

[0061] The processing unit 8 provides the antinoise signal on the output side. The antinoise signal is calculated from the data of the reference sensor 23 or from the data detected by the microphones 10 depending on whether the noise reduction system 2 is a feedforward system (with a reference sensor 23) or a feedback system (without a reference sensor 23).

[0062] The sound generators 12 are configured to generate antinoise from the antinoise signal, which antinoise is superimposed on the background noise within the right-hand and left-hand quiet zone 20a, 20b such that the background noise is actively reduced.

[0063] If the user moves their head, said movement is detected by the position detection unit 14 and the quiet zones 20a, 20b are also moved in a corresponding manner. It is therefore possible to provide efficient active noise damping, for example in a utility vehicle, in particular a construction machine or agricultural machine.

[0064] According to another exemplary embodiment, the noise reduction system 2 is developed in that the 3D camera arrangement 14 forms a spatially enclosed structural unit together with the microphones 10, the sound generators 12 and the control unit 8. This is shown in FIG. 2. In this figure, the noise reduction system 2 is completely integrated in the headrest 6 of the motor vehicle. The 3D camera arrangement 14, comprising the first camera 18a and the second camera 18b, is attached to the side of the headrest. The remaining elements of the noise reduction system 2 have already been described in connection with FIG. 1. Using the 3D camera arrangement 14, the position of the head 16 of the user is detected such that the virtual microphone 22a can be moved along together with the movement of the head 16 of the user. By way of example, only the virtual microphone 22a for the right ear of the user is shown. Of course, there is also a left-hand virtual microphone (not visible in the figure) on the opposite side of the head 16 of the user. Said microphone is of course also moved along during movements of the head of the user.

[0065] FIG. 3 shows the system known from FIG. 2 in a schematically simplified perspective view. By way of example, said system comprises eight microphones, which are arranged along the upper and lower edge of the headrest 6. The first camera 18a and the second camera 18b are arranged such that a stereo base B extending between the cameras extends from top to bottom. In other words, the first camera 18a is arranged higher than the second camera 18b. The stereo base B is in particular vertically arranged, i.e., it extends in an at least approximately perpendicular manner. The cameras 18a, 18b of the 3D camera arrangement 14 are arranged in a lateral portion of the headrest 6. Said cameras are arranged in the headrest 6 such that they can detect the head 16 of the user at the side from behind.

[0066] FIGS. 4 and 5 show another exemplary embodiment of a noise reduction system 2. In this case, too, the 3D camera arrangement 14, comprising the first camera 18a and the second camera 18b, the microphones 10, the sound generators 12 and the control unit 8 are housed in a spatially enclosed structural unit. Said unit is mounted on a headrest 6 of a motor vehicle. Belts (not shown) may for example be used to fasten the unit to the headrest 6. Furthermore, the unit may additionally be fastened to the support rods 24 of the headrest 6, if required. The control unit 8 is arranged in the rear portion of the unit (not visible in the figure and therefore shown as a dashed line). The unit projects beyond the headrest 6 on both sides in a horizontal direction, at least the sound generators 12 being housed in the lateral portions 26 projecting beyond the headrest 6. According to the exemplary embodiment shown, one portion 26 projecting beyond the headrest 6 also comprises the 3D camera arrangement 14.

[0067] FIG. 5 shows the noise reduction system 2 known from FIG. 4 in a schematically perspective view. For reasons of clarity, the 3D camera arrangement is not shown in FIG. 5.

[0068] Similarly, the electrical connections used for the data connection between the individual units and for the power supply thereof are not shown in any of the figures for reasons of clarity. Said electrical connections are achieved using conventional technical means.

[0069] The control unit 8 of the noise reduction system 2 comprises a neural network that is configured to receive the image data or image data stream generated by the 3D camera arrangement 14. The neural network processes said 3D image data and outputs a position signal which indicates the position and/or orientation of the head 16 of the user relative to the position detection unit 14.

[0070] According to a method for actively compensating background noises in a passenger transport area of a vehicle, in particular a construction machine, a background noise is detected using a microphone 10 and the background noise is converted into a background noise signal by the microphone 10. By means of a 3D camera arrangement 14, which provides a position detection unit, position data is detected and a position signal is determined from said position data. This takes place, for example, in the control unit 8. The position signal indicates a position and/or orientation of the head 16 of a user in the passenger transport area relative to the position detection unit. An antinoise signal is generated from the background noise signal and the position signal and said antinoise signal is converted into antinoise by a sound generator 12, which is preferably a loudspeaker. The antinoise is superimposed on the background noise so as to be in phase opposition therewith in one, preferably two, quiet zones 20a, 20b located within the passenger transport area and located within immediate proximity of the ears of the user, such that the background noise is actively reduced in the quiet zones 20a, 20b.

[0071] All named features, including those taken from the drawings alone and also individual features which are disclosed in combination with other features, are considered alone and in combination as essential for the invention. Embodiments according to the invention can be fulfilled by individual features or a combination of several features. Within the scope of the invention, features which are designated with in particular or preferably are understood to be optional features.

LIST OF REFERENCE SIGNS

[0072] The following reference signs appear in the accompanying drawing figures: [0073] 2 Noise reduction system [0074] 4 Driver's seat [0075] 6 Headrest [0076] 8 Control unit [0077] 10 Microphone [0078] 12 Sound generator [0079] 14 3D camera arrangement [0080] 16 Head [0081] 18a First camera [0082] 18b Second camera [0083] 20a Right-hand quiet zone [0084] 20b Left-hand quiet zone [0085] 22a Right-hand virtual microphone [0086] 23 Reference sensor [0087] 24 Support rods [0088] 25 Noise source [0089] 26 Lateral portion [0090] B Stereo base