DE102016005876A1 - Fixed localized noise suppression in a motor vehicle - Google Patents

Abstract

The invention relates to a method for suppressing background noise (4) in a motor vehicle (1), with detection of an interference sound (4) by at least one microphone (3) of the motor vehicle (1), determining a compensation sound signal (6) for compensating the noise (4) by a computing unit (5) of the motor vehicle (1) taking into account the detected noise (4), outputting the determined compensation sound signal (6) by at least one loudspeaker (7) of the motor vehicle (1), wherein the at least one microphone ( 3), the arithmetic unit (5) and the loudspeaker (7) are part of a speech system (2), and the compensatory sound signal (6) is determined such that it compensates the background noise (4) at a predetermined location (15) at which the one or another microphone (3) of the speech system (2) for detecting a speech signal (12) is fixedly arranged in the motor vehicle (1) in order to improve the speech quality in the motor vehicle (1). The invention also relates to a corresponding speech system (2) and a motor vehicle (1) with such a speech system (2).

Description

The invention relates to a method for suppressing background noise in a motor vehicle, with detecting a noise by at least one microphone of the motor vehicle, a determination of a compensation sound signal for compensating the noise by a computing unit of the motor vehicle taking into account the detected noise and outputting the calculated compensation sound signal at least one speaker of the motor vehicle. The invention also relates to a corresponding speech system for a motor vehicle.

Hands-free or voice-operated systems integrated into vehicles today include voice signals from vehicle occupants with at least one corresponding hands-free microphone. These recorded or recorded speech signals are then made available to a computing unit, which analyzes these with a speech signal processing algorithm or forwards them to other persons or devices, usually located outside the motor vehicle. Due to the resulting when driving the motor vehicle driving noise and other noise, for example by other vehicle occupants, in addition to the actual voice signal, such as a voice command or a language driving noise or other sounds are detected by the hands-free microphone and forwarded to the arithmetic unit. The speech signal processing algorithm in the arithmetic unit now has the task of calculating this additional noise, the background noise, from the acquired speech signal.

The detected speech signal is thus a mixed signal, which consists of the voice or the voice command and a noise such as the driving noise. In the case of the speech signal processing algorithms used for suppressing the background noise, the noise component is often also reduced by means of estimates. How much the noise or noise components are reduced can typically be adjusted in the speech signal processing algorithm. The noise can be lowered for example by 12 decibels. However, the background noise can also be lowered or compensated by more than 20 decibels if appropriate settings are made in the arithmetic unit.

The disadvantage of an ever stronger noise or noise reduction is that the voice signal, ie the useful signal or the voice based on the usually frequency-based noise reduction algorithms of the speech signal processing algorithm is increasingly alienated and the language is increasingly affected in their quality. This reduces the quality of telephone conversations and / or the performance of a voice control system, since even an automatic voice recognition is difficult.

Is known in this context, for example, from the DE 10 2004 008 614 A1 a device for sound compensation in a vehicle having a sound detection device for detecting a sound signal in the interior of the motor vehicle, a computing device for calculating an anti-phase compensation sound signal as a function of the detected sound signal and a sound conversion device for outputting the anti-phase compensation sound signal to the interior of the motor vehicle.

The DE 10 2014 210 760 A1 discloses a method for operating a communication system in a vehicle, wherein a first input signal is detected at a first signal detection device, which comprises a speech signal of a speaker, and an output signal based thereon is sent to a receiver by means of the communication system. It can be removed by means of a spectral filtering noise, which are not relevant to the language.

The DE 10 2013 011 761 A1 discloses a motor vehicle with a hands-free device, which comprises a microphone for detecting a disturbed speech signal. The microphone is here connected to a signal processing unit for noise reduction of the background noise of the disturbed speech signal, which includes a filter device for generating a handsfree frequency response. The filter device is designed as a dynamic filter, which comprises an estimation unit and a unit for a reference spectrum for a speech signal for determining a filter characteristic.

This results in the task of improving the voice quality in a motor vehicle, in particular for voice recognition and / or voice transmission.

This object is solved by the subject matters of the independent claims. Advantageous embodiments will become apparent from the dependent claims, the description and the figures.

The invention relates to a method for suppressing background noise in a motor vehicle, preferably for suppressing background noise with a speaking system in a motor vehicle. In this case, the method comprises detection of an interference sound by at least one microphone of the motor vehicle. It also includes predetermining or determining a compensating sound signal for compensating or Suppressing the Störschalls by a computing unit of the motor vehicle, taking into account the detected noise. The compensation sound signal can be predetermined at a predetermined location or in a predetermined local area in antiphase to the background noise. This can be locally extinguished sound waves and the associated sound can be suppressed. This is also known as active noise cancellation or so-called Active Noise Canceling, for example of noise canceling headphones. Finally, the method comprises outputting the predetermined compensation sound signal by at least one loudspeaker of the speech system. The determination or presetting of the compensatory sound signal can here comprise a modification and / or setting of a phase and / or frequency distribution of the compensation sound signal as well as a volume of the compensation sound signal.

The at least one microphone, the arithmetic unit and the speaker are part of a speech system. The speech system may in particular also comprise an operating unit for controlling the speech system and / or a speech recognition unit. The speaking system may be a system of the motor vehicle which is designed to detect and evaluate and / or forward speech signals of a user. For example, a voice control system or a telephone system such as a car phone may be referred to as a speaking system. The speech system may also include a hearing system. The hearing system can be a system of the motor vehicle which is designed to acoustically transmit auditory signals to a user. For example, a radio can be called a hearing system.

The compensation sound signal is now determined by the arithmetic unit in such a way that it compensates the background noise at least at a predetermined location or in a near area around the location at which a microphone of the speech system for detecting a speech signal is fixed or fixed in the motor vehicle. The near zone may be limited to locations less than 40 cm, less than 20 cm, less than 10 cm, less than 5 cm or less than 2 cm from the predetermined location of the microphone. For example, the predetermined location may be located on an instrument panel and / or a steering wheel and / or a vehicle roof and / or an A-pillar and / or a center console of the motor vehicle.

This has the advantage that the microphone of the speech system now already receives a noise-compensated speech signal for transmission and / or evaluation by the speech recognition unit. Since the compensation sound signal now generates the noise at a fixed location in the motor vehicle, the compensation sound signal can also be more accurately determined or specified. The known uncertainties in existing systems, which compensate for the noise, for example, at the location of a moving head of a driver omitted here. It is created around the microphone of the speech system for detecting the speech signal, such as a hands-free microphone, an improved quiet noise zone, and recorded less acoustic noise in the hands-free microphone. The consequence here is that the further transmitted or to be analyzed signal only comprises a weakened noise or a weakened noise component, a desired speech signal, such as a voice of an occupant, but is not affected.

Thus, a speech signal processing algorithm may be provided with a signal of the microphone or hands-free microphone having an improved signal-to-noise ratio. This, in turn, has the advantage that noise suppression by the signal processing algorithm, which is known to reduce speech quality, can be reduced in strength or the speech signal processing algorithm can generate an output signal by the now available higher signal-to-noise ratio of the speech signal detected by the microphone. which is almost free of noise and includes a clean voice signal. Thus, for example, telephone calls or entries in a voice dialogue system or voice control system can benefit significantly. For example, conversations can become more pleasant or a recognition rate of a voice control system can be increased.

In an advantageous embodiment it is provided that the method here also includes providing information about at least one operating parameter of the motor vehicle by a control unit of the motor vehicle independent of the speech system to the arithmetic unit. Furthermore, it includes a consideration of a change of the at least one operating parameter in the predetermination of the compensation sound signal on the basis of the information provided.

This has the advantage that the otherwise usual in the field of active noise reduction or noise suppression usual delay, which naturally results in a newly occurring background noise, omitted. Since the arithmetic unit does not have to wait for a certain time, as in the prior art, in order to be able to detect whether a detected noise is actually an interference sound or a desired sound signal, for example a voice signal, the background noise is suppressed without delay. This is possible because the arithmetic unit based on the change of the operating parameter and others in the arithmetic unit stored information about a to be expected in the change of the operating parameter noise does not re-recognize the sound detected by the microphone noise itself as such. This results in an improved suppression of noise in a motor vehicle, which can suppress a newly occurring background noise or a changing background noise faster. A background noise can also have several, independent sources. In this case, corresponding interference sound components and associated compensation sound components can be controlled or determined independently of respectively further components by the arithmetic unit.

In an advantageous embodiment, it is provided here that the operating parameter comprises a travel speed of the motor vehicle and / or a vehicle-internal adjustment of the motor vehicle which can be set, for example, by a user. Especially the driving speed is an important factor and is often the cause of specific background noise, so that their consideration is particularly advantageous. Other vehicle-internal settings can affect the activity of aggregates in the vehicle and thus the occurrence of background noise in the vehicle or in the passenger compartment. This has the advantage that, for example, with frequent changes in the driving speed, the change constantly produced by the new driving speed, for example, a component of the noise can be compensated faster than in a conventional noise reduction or, for example, a different component of the subcomponent residual noise, which on other cause is due. Thus, the background noise, which changes frequently for the mentioned conditions, can be suppressed particularly effectively and a better voice quality can be achieved in a large number of everyday situations in the motor vehicle.

In an advantageous embodiment, it is provided here that the vehicle-internal setting is a cylinder deactivation of a drive motor of the motor vehicle, wherein the changing here comprises activating and / or deactivating, and / or a speed specification for the motor vehicle, in particular a position of the gas pedal of the motor vehicle, and / or a driving dynamics setting of the motor vehicle and / or an opening degree of at least one window of the motor vehicle and / or an operating state of an air conditioning device of the motor vehicle. Especially the mentioned settings often cause a noise in a particularly disturbing low-frequency range below 700 Hz, in particular below 500 Hz, which is difficult to suppress with alternative noise reduction methods. In addition, said vehicle-internal settings of the motor vehicle in a regular operation of the same often change, so here with conventional systems for a user of the motor vehicle, a noticeably worse noise suppression is achieved. Taking into account the aforementioned vehicle-internal settings is thus again useful for improved suppression of background noise in the motor vehicle.

In another embodiment, it is provided that further properties of the motor vehicle are taken into account by the arithmetic unit when taking into account the change. In particular, for example, an engine and / or a body shape and / or an interior such as the presence of a glass roof or panoramic roof can be considered here. The properties mentioned influence the noises occurring during the respective changes of the operating state and thus the properties of the noise to be suppressed. Therefore, taking into account the properties, for example in the form of stored in the arithmetic unit properties of occurring for given properties of the motor vehicle under predetermined conditions noise is possible, for example in the form of a frequency distribution of an expected noise. Thus, an improved suppression of noise is also achieved here.

In a further embodiment, it is provided that, when determining the compensation sound, the arithmetic unit takes into account the change in the at least one operating parameter for frequency components of the compensation sound, which are below 700, preferably below 500 hertz. In particular, when calculating the compensation sound, the arithmetic unit can only take into account the change in the at least one operating parameter, that is, exclusively for frequency components of the compensation sound which are below 700 or 500 hertz. This has the advantage that the particularly disturbing low frequencies of the noise are suppressed. Precisely because the said low frequencies are difficult to compensate with other measures, for example acoustic insulation, the use of the active noise suppression in the form of the described suppression of noise is advantageous here.

In a further embodiment it is provided that the outputting of the compensation sound signal takes place only when the speech system is activated, in particular when a speech recognition device of the speech system expects a speech signal of the user. This has the advantage that side effects of active noise suppression or noise suppression are prevented especially for other people and at the same time a reliable and secure transmission of a voice signal is achieved. Especially for example in a navigation device, which is controlled via the speech system a voice command of a user, so can also be contributed to increased security due to the improved intelligibility.

The invention also relates to a speaking system for a motor vehicle having a microphone arranged fixedly in the motor vehicle, which is suitable for detecting an interference sound and for detecting a speech signal of a user, a computing unit for determining a compensation sound signal for compensating or suppressing the noise, taking into account the detected noise and with at least one speaker for outputting the predetermined compensation sound signal. In this case, the arithmetic unit is designed to compensate for the background noise at a predetermined location by the compensation sound signal, at which the one or another microphone of the speech system for detecting a speech signal is fixedly arranged or fixed in the motor vehicle.

The speaking system may comprise a hands-free system and / or a voice control system for operating functions of the motor vehicle by voice signals.

The invention also relates to a motor vehicle having a speaking system according to one or more of said embodiments.

Advantages and advantageous embodiments of the speech system correspond here to advantages and advantageous embodiments of the described method for suppressing background noise.

The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the figure description and / or shown alone in the figure, can be used not only in the respectively indicated combination but also in other combinations or in isolation, without the frame to leave the invention. Thus, embodiments of the invention are to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, however, emerge and can be produced by separated combinations of features from the embodiments explained. Thus, embodiments and combinations of features are to be regarded as disclosed, which thus do not have all the features of an originally formulated dependent or independent claim.

Embodiments of the invention will be explained in more detail with reference to a schematic drawing. The single figure shows a schematic representation of a motor vehicle with an exemplary embodiment of a speaking system.

In the figure is a motor vehicle 1 with a speech system 2 shown. The speech system 2 serves here for detecting and transmitting and / or evaluating speech signals 12 , It includes a microphone in the example shown 3 , which is designed here as a hands-free microphone, with which a voice signal 12 as well as a background noise 4 is detectable. The speech system 2 also includes a computing unit 5 for determining a compensation sound signal 6 for compensating or suppressing the noise 4 , It is by the arithmetic unit 5 the detected background noise 4 considered in the determination. Furthermore, the speech system includes 2 at least one, in this case two speakers 7 for outputting the determined compensation sound signal 6 , In the example shown, the speech system comprises 2 also a speech recognition device 13 which provides a result of speech recognition to another component 14 , For example, a driver assistance system, the motor vehicle 1 can be transmitted.

Shown in this example is also an engine 10 , For example, a drive motor, as a source of noise 4 , The background noise 4 however, it may also be caused additionally or alternatively by other sources. In the example shown, the engine is 10 by a control unit 9 controlled, which is a position of an accelerator pedal 8th detected.

The arithmetic unit 5 is now designed here, by the compensation sound signal 6 the background noise 4 at a given location 15 or to compensate for a location area, on which in the example shown the microphone 3 , or another microphone of the speech system for detecting the speech signal 12 firmly in the motor vehicle 1 is arranged. Through the arithmetic unit 5 So is the compensation sound signal 6 determined such that at the given location 15 , which is located here on an inner surface of the passenger compartment, the noise 4 is compensated. The place 15 or the local area remains in its position within the motor vehicle 1 always unchanged. In particular, therefore, not to a position of the user 11 or a head of the same adapted. He also deliberately does not include the user's headspace here 11 , The local area 15 thus forms a noise-quieted zone, within which the background noise 4 through the compensation sound signal 6 at least partially, that is, completely or partially compensated.

Is now the speech system 2 active and expected, for example, the speech recognition device 13 a voice signal 12 of the user 11 so can the compensation sound 6 for the local area 15 here through the speakers 7 be issued. This is done by the microphone 3 , here the hands-free microphone in the local area 15 , the background noise 4 only recorded in a reduced or insignificant form. The speech signal 12 however, the user 11 is inherently of the compensation sound signal 6 not or only minimally affected, since the compensation sound signal 6 to the background noise 4 is adjusted, but not to the speech signal 12 , Thus, the speech signal becomes 12 from the microphone 3 as a hands-free microphone with an improved signal-to-noise ratio (SNR). This in turn increases the quality of the speech recognition device 13 , so that as a result, here also a functionality of the other component 14 of the motor vehicle 1 improves on the speech signals 12 of the user 11 responding.

The compensation sound 6 here becomes dynamic depending on the respective background noise 4 generated, so even with a change, for example, the position of the accelerator pedal 8th and a correspondingly changed new background noise 4 the speech signal with the improved signal-to-noise ratio through the microphone 3 is detected. Particularly advantageous here is a coupling, not shown, of the control unit 9 with the arithmetic unit 5 through which the arithmetic unit 5 over a changed Störschall 4 Information gets before the background noise 4 actually changed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004008614 A1 [0005]
• DE 102014210760 A1 [0006]
• DE 102013011761 A1 [0007]

Claims (10)

Method for suppressing background noise ( 4 ) in a motor vehicle ( 1 ), with a - detecting a noise ( 4 ) by at least one microphone ( 3 ) of the motor vehicle ( 1 ); Determining a compensation sound signal ( 6 ) for compensating the noise ( 4 ) by a computing unit ( 5 ) of the motor vehicle ( 1 ) taking into account the detected background noise ( 4 ); Outputting the determined compensation sound signal ( 6 ) by at least one speaker ( 7 ) of the motor vehicle ( 1 ); characterized in that the at least one microphone ( 3 ), the arithmetic unit ( 5 ) and the speaker ( 7 ) Part of a speech system ( 2 ), the compensation sound signal ( 6 ) is determined such that it the Störschall ( 4 ) at a given location ( 15 ) on which the one or another microphone ( 3 ) of the speech system ( 2 ) for detecting a speech signal ( 12 ) fixed in the motor vehicle ( 1 ) is arranged. A method according to claim 1, characterized in that and by - providing information about at least one operating parameter of the motor vehicle ( 1 ) by one of the speech system ( 2 ) independent control unit ( 14 ) of the motor vehicle ( 1 ) to the arithmetic unit ( 5 ); and a - taking into account a change of the at least one operating parameter in the determination of the compensation sound signal ( 6 ) based on the information provided. Method according to Claim 2, characterized in that the operating parameter is a travel speed of the motor vehicle ( 1 ) and / or an in-vehicle variable vehicle-internal adjustment of the motor vehicle ( 1 ). Method according to one of claims 2 or 3, characterized in that the vehicle-internal adjustment of the motor vehicle ( 1 ) a cylinder deactivation of a drive motor ( 10 ) of the motor vehicle ( 1 ) and / or a speed specification for the motor vehicle ( 1 ), in particular a position of an accelerator pedal ( 8th ) of the motor vehicle ( 1 ), and / or a vehicle dynamics adjustment of the motor vehicle ( 1 ) and / or an opening degree of at least one window and / or an operating state of an air-conditioning device of the motor vehicle ( 1 ). Method according to one of claims 2 to 4, characterized in that by the arithmetic unit ( 5 ) taking into account the change further properties of the motor vehicle ( 1 ), in particular an engine and / or a body shape and / or an interior. Method according to one of claims 2 to 5, characterized in that the arithmetic unit ( 5 ) in determining the compensation sound ( 6 ) the change of the driving speed and / or the vehicle-internal adjustment of the motor vehicle ( 1 ) for frequency components of the compensation sound ( 6 ), which are below 700 Hz, preferably below 500 Hz. Method according to one of claims 2 to 6, characterized in that the outputting of the compensation sound signal ( 6 ) only takes place when the speech system ( 2 ) is activated, in particular only if a speech recognition device of the speech system ( 2 ) the speech signal ( 12 ) of a user ( 11 ) expected. Speech system ( 2 ) for a motor vehicle ( 1 ), with - at least one fixed in the motor vehicle ( 1 ) arranged microphone ( 3 ), for detecting a Störschalls ( 4 ) and for detecting a speech signal ( 12 ) of a user ( 11 ); - a computing unit ( 5 ) for determining a compensation sound signal ( 6 ) for compensating the noise ( 4 ) with a consideration of the detected noise ( 4 ); At least one loudspeaker ( 7 ) for outputting the determined compensation sound signal ( 6 ); and characterized in that the arithmetic unit ( 5 ) is designed by the compensation sound signal ( 6 ) the background noise ( 4 ) at a given location ( 15 ) on which the one or another microphone ( 3 ) of the speech system ( 3 ) for detecting a speech signal ( 12 ) fixed in the motor vehicle ( 1 ) is arranged. Speech system ( 2 ) according to claim 8, characterized in that the speech system ( 2 ) a hands-free system and / or a voice control system for operating functions of the motor vehicle ( 1 ) by voice signals ( 12 ). Motor vehicle ( 1 ) with a speech system ( 2 ) according to claim 8 or 9.

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