DE10013432C1 - Microphone device installed in automobile positioned in front of driver facing towards front windscreen for reception of speech signals reflected from windscreen surface - Google Patents

Abstract

The microphone device (6) is installed in the automobile passenger compartment adjacent the bottom edge of the front windscreen (2), in front of the driving seat, by incorporating it in the top surface of the instrument panel. The microphone device is positioned so that its main sensitivity axis faces towards the windscreen, for reception of speech signals reflected from the windscreen surface.

Description

The invention relates to a microphone arrangement near a Windshield in front of a driver's seat in an interior Motor vehicle.

Telephone systems in motor vehicles should be one Have handsfree, so that the driver during a Calls his hands for the operation of the motor vehicle freely available. With stationary installed in the vehicle Handsfree is usually above the microphone Windshield arranged approximately in the middle, in usually on or in the holder of one in the vehicle interior Rearview mirror arranged to observe the Traffic behind the respective vehicle. For example, WO 98/00926 is on a rear view mirror arranged microphone known.

If necessary, the aforementioned microphone can be provided not only for voice transmission during a phone call use. Rather, the microphone can also be used for voice control the telephone system, for example to dial one Telephone connection of a desired conversation partner, and / or for voice control of other devices in the vehicle be used, for example to operate a Navigation system or a radio or the like known from DE 43 20 976 A1, for example, a microphone in the driver’s conversation area directly opposite the Windshield, e.g. B. on the steering wheel or on the dashboard, to arrange.  

The installation of the microphone on or in the mirror holder is therefore advantageous as the mirror holder in today's vehicles regularly with interior lighting or associated, manually operated switches is combined, so that at the laying of the necessary for the lights or switches electrical wiring also the electrical wires of the  Microphones can be routed and the microphone is an element a mirror holder assembly.

Nevertheless, it is an object of the invention to provide an improved To create a microphone arrangement.

This object is achieved by the features specified in claim 1. A close to the is advantageous Lower part of the windshield above one Instrument arrangement in the driver's main line of sight arranged microphone, which is in one of Structural parts of the vehicle body separately poorly sound-conducting material existing support part of the Instrument arrangement or in a corresponding Instrument carrier is arranged.

The invention is based on the general idea in which Position the microphone a good approximation to the zone maximum speech sounds when the driver is in normal posture to reach. This results in an improved microphone Signal-to-noise ratio, as this is due to the speech sound formed signal stronger from background noise in one Vehicle takes off. In addition, it is advantageous that the Instrument holder or microphone holder vehicles common today for reasons of accident safety regularly from a relatively compliant and the sound there is poorly conductive material and accordingly Noise separates the microphone from the body.

In addition, there are a variety of Measuring and electronic elements combined. The one for installation of these elements during the pre-assembly of the instrument holder necessary work is similar to the installation work for the Microphone, so that a "harmonization" of the Installation work to be performed is given, the spatial proximity of the microphone to assigned expediently arranged in the instrument carrier Electronic modules is advantageous.  

According to a particularly preferred embodiment of the Invention are several microphones in the vehicle transverse direction spaced from each other at the upper edge of the instrument carrier or the like. Even when the driver turns his eyes so that at least one microphone is always optimal for Major axis of the speech sound.

The microphone or the microphones are preferably with their Main sensitivity axis on the windshield aligned, such that the sound emitted by the driver down from the windshield in the direction of of a microphone is reflected.

The instrument carrier usually has in today's Motor vehicles a more or less large, below the Windshield extended into the vehicle interior Horizontal or sloping surface that is used to arrange visually indicators and instruments to watch is unsuitable and accordingly a great deal of freedom in Arrangement of the microphone or microphones offers. Through the The usual curvature of the windshield is reflected the speech sound a certain bundling of sound to the microphone reached.

According to a particularly advantageous embodiment of the Invention is provided with the microphone or microphones digital signal outputs or with analog-digital To provide transducers so that the voice signals as digital Signals electronically forwarded and, if necessary, also can be processed.

In principle, in the context of digital signal processing all measures are taken that are already available for hearing aids from Hearing impaired were developed.  

For example, the sound picked up by the microphone pronounced frequency selective evaluation by z. B. Sound frequencies outside the usual Speech frequency range are filtered out. That's the way it is Frequency range of music played on a car radio in the Vehicle interior becomes audible, to a considerable extent below the frequency range of human speech. This This makes it easy to suppress noise.

In addition, the arrangement of multiple microphones Phase position of the recorded sound can be evaluated. Also with large differences in the body sizes of different drivers the driver's head remains within one comparatively small space zone because the driver is driving the vehicle can only lead well and easily if he is in his usual target position sits. But this is synonymous so that the driver's speech sound at multiple arranged microphones to similar signal structures leads that are phase-shifted in a characteristic manner. This phase shift can be used as a selective feature Suppression or non-observance of other sound signals be exploited, which are also similar Signal structures on the microphones, but signal structures lead with significantly different phase shifts. For example, the position of the driver's head comparatively far from speakers one possibly radio system arranged in the vehicle. This is synonymous with that from the driver's speech sound caused microphone signals a significantly different Phase shift than that caused by speaker sound Have microphone signals.

Finally, the microphone or microphones associated signal processing electronics with electrical or electronic control systems of the vehicle for one Data exchange must be networked, so that the aforementioned Signal processing electronics can "know" whether or in  which way noise generating systems of the vehicle work. So the signal processing electronics for example, "be communicated" whether or to which Working stage of a windshield wiper system of the vehicle is switched whether or with what power Ventilation fan works whether or under what load the engine of the vehicle works etc. So that "knows" the Signal processing electronics also the respective Sound spectrum of the background noise to be expected, so that these can be suppressed during signal processing.

If necessary, the signal processing system can be adaptive or be designed to be adaptable to optimal adaptation different vehicle types or changing ones To be able to offer operating conditions.

Otherwise, the preferred features of the Invention on the claims and the following explanation referred to the drawing, based on the particularly preferred Embodiments of the invention are described in more detail.

It shows

Fig. 1 is a fragmentary, schematic side view of a vehicle interior,

Fig. 2 is a highly schematic view of a angeordenten in the vehicle interior instrument panel from the perspective of the driver, wherein the positions of different microphones are indicated,

Fig. 3 is a block diagram for the signal evaluation circuit combined with the microphones and

Fig. 4 is a block diagram of a particularly preferred embodiment.

A motor vehicle shown only in part in FIG. 1 has an interior 1 , which is closed in the forward direction by a windshield 2 , under which an instrument carrier 3 with a horizontal or slightly inclined upper side 3 'facing the windshield 2 is arranged in the usual way is.

Furthermore, FIG. 1 shows the heads and upper bodies 4 , 4 'of two drivers of different sizes in a typical sitting position with a view of the windshield 2 . When the driver 4 or 4 'in the position shown uses a hands-free device in the vehicle, the speech sound is reflected from the windshield 2 to the top 3 ' of the instrument carrier 3 , as is illustrated by lines 5 , 5 ', which the Clarify zones of maximum sound intensity of the speech sound emanating from the driver 4 or 4 '.

A microphone 6 arranged according to the invention on the upper side 3 'of the instrument carrier 3 lies in the area of very high speech sound intensity when arranged approximately in the direction of view of the driver 4 or 4 '.

Referring to FIG. 2, the microphone 6 is arranged combi-instrument display 7 in the instrument carrier 3 above a designated in the viewing direction of the driver, more preferably 3 microphones 8 are provided wherein the side of the microphone 6 on the top 3 'of the instrument carrier.

The multiple arrangement of the microphones 6 and 8 ensures, on the one hand, that at least one of these microphones lies in the direction of the maximum intensity of the speech sound, even when the driver looks at his eyes. On the other hand, with multiple arrangement of the microphones 6 and 8, there is the possibility of evaluating the phase shifts between the microphone signals. Since the head of the speaker or driver has different distances from the microphones 6 and 8 , the words of the speaker reach the different microphones 6 and 8 at different times, that is to say that phase shifts inevitably occur, these phase shifts being largely independent of the direction of view of the speaker are. It is also advantageous that these phase shifts differ from the phase shifts that are characteristic, for example, of music or voice messages from the car radio.

According to FIG. 3, according to a particularly preferred embodiment of the invention, an analog-to-digital converter is provided downstream of the microphones 6 and 8 so that the speech sound can be converted into digital electronic signals.

In the example of FIG. 3, the microphones 6 and 8 are connected in parallel to a multiplexer 9 , which in turn is connected upstream of the analog-digital converter 10 . A circuit 11 for signal processing is connected downstream of the analog-digital converter 10 .

This signal processing unit 11 can, for example, examine the signal sequences of the different microphones 6 and 8 for similar structures that occur on the microphones 6 and 8 with a phase shift characteristic of the speaker. Signal structures with other phase shifts, however, can be suppressed to a greater or lesser extent.

Furthermore, the signal processor 11 can receive information via an input 12 about which noise sources are switched on in the vehicle.

For example, the signal processor 11 can be informed whether a windshield wiper (not shown) is switched on or at what actuation level the windshield wiper is operating.

In addition, the signal processor 11 can receive operating data on the working state of the vehicle engine and the gear stage that is switched on. The signal processing unit 11 can thus suppress the noise to be expected accordingly, ie the signals produced by the noise to be expected, to a greater or lesser extent.

In addition, the signals generated by the application of sound to the microphones 6 and 8 can be processed selectively according to the frequency of the sound recorded. For example, the frequency spectrum of a person's speech sound is generally well above the average frequency spectrum of music performances on the radio, so that the voice control of devices in the motor vehicle can be facilitated even when the radio is switched on.

As soon as the signal processor 11 "recognizes" that a command has been spoken, the radio can also be temporarily muted or brought to a very low volume.

The signal conditioning 11 is connected to a control unit 13 , which can forward the signals via various outputs, e.g. B. to a telephone transmitter, a voice controlled radio or navigation system or the like.

In the embodiment of FIG. 4, the microphones 6 and 8 are in turn followed by a multiplexer 9 and an analog-digital converter 10 synchronized therewith.

Subsequently, the digital output signals of the converter 10 are further processed on an upper processing path in FIG. 4 to a guide signal F for sound optimization of audio systems in the vehicle and / or on a lower processing path in FIG. 4 to an optimized speech signal S, which for example is one Telephone system is fed.

To generate the reference variable F, the output signals of the converter 10 are fed to a signal conditioning circuit 15 which functions as an adaptive filter and which is followed by an inverse adaptive filter 16 and a standardization unit 17 . The signal conditioning unit 15 can be connected to a bus system 18 , via which different control systems of the vehicle are in data exchange with one another. Via this bus system 18 , the signal conditioning unit 15 "recognizes", for example, which units are switched on in the vehicle or in which operating state these units are. The signal conditioning unit 15 thus “knows” which noises are generated by these units.

The subsequent inverse adaptive filter 16 is likewise connected to the bus system 18 and additionally receives, for example from an audio bus 19 , bus data or the like from an audio system located in the vehicle. After normalization in the standardization unit 17 , the noise of the vehicle is then available as a standardized reference variable for an optimized operation of audio devices. This reference variable, which should cover a value range from zero percent to 100%, can then be used by the audio units to adapt the volume of audio devices using automatic actuators or to optimally adapt the equalizing and loudness curves to the respective situation.

On the lower processing path in FIG. 4, the output signals of the converter 10 are first subjected to a fast Fourier transformation in a unit 20 and then fed to a signal estimation unit 21 which also evaluates the data of the bus systems 18 and 19 . The output signals of unit 21 are then supplied to a compensation unit to compensate for signal timing delays and subsequently in a an inverse Fourier transform performing subtraction unit 23 together with the signal conditioning unit 15 next data is subtractively processed, supplied to the unit 23 via a Fourier transform unit 20 become. In this way, the signal-to-noise ratio of the signals, which represent the speech recorded by the microphones 6 and 8 , can become very important under very different operating conditions of the vehicle.

In all the signal processing described above, the bus system 18 can provide data which, for example, reflect the type of vehicle, the variant of the steering system of the vehicle, the current vehicle speed, the operating state of slip control systems and / or anti-lock braking systems or the open state of the windows or the top.

The noises detected via the microphones 6 and 8 or the bus lines 18 and 19 can also be taken into account when operating signal tone generators, in order to be able to generate the necessary acoustic warning signals in the vehicle in different operating situations, on the one hand, to be clearly audible and, on the other hand, to be able to generate them without undue volume, where appropriate also differently placed signal tone generators can be controlled differently.

Claims (8)

1. Microphone arrangement with at least one microphone ( 6 ) near a sub-area of a windshield ( 2 ) in front of a driver's seat in the interior of a motor vehicle, characterized in that the microphone ( 6 ) is arranged above an instrument arrangement ( 7 ) and with its main sensitivity axis on the Windshield ( 3 ) is oriented such that speech sound emanating from the driver ( 4 ) is reflected downward from the windshield ( 3 ) in the direction of the microphone ( 6 ). 2. A microphone assembly according to claim 1, characterized in that the microphone (6) of the instrument assembly (7) and is arranged in an instrument carrier (3) in one of structural parts of a body separate, consisting of poorly schalleitendem material support part (3). 3. Microphone arrangement according to claim 1 or 2, characterized in that a plurality of microphones ( 6 , 8 ) spaced apart from one another in the vehicle transverse direction are arranged on the upper edge of an instrument carrier ( 3 ) or the like. 4. Microphone arrangement according to one of claims 1 to 3, characterized in that the microphones ( 6 , 8 ) are aligned with their main sensitivity axis on the windshield ( 3 ), such that the driver emits speech sound from the windshield downwards in the direction at least one of the microphones is reflected. 5. Microphone arrangement according to one of claims 1 to 4, characterized in that the at least one microphone ( 6 , 8 ) generate digital signals or are combined with analog-digital converters to generate such signals. 6. Microphone arrangement according to one of claims 1 to 5, characterized in that when several microphones ( 6 , 8 ) are arranged, phase shifts between the microphone signals can be evaluated. 7. Microphone arrangement according to one of claims 1 to 6, characterized, that signals at given speech frequencies are preferred are processed. 8. Microphone arrangement according to one of claims 1 to 7, characterized in that a signal conditioning ( 11 ) is networked with electrical or electronic control systems of the vehicle for data exchange, so that expected noise from noise-generating systems, for. B. windshield wipers, motor or transmission, can be compensated for in signal processing.