CN105139860B

CN105139860B - Communication device and method for operating the same

Info

Publication number: CN105139860B
Application number: CN201510301094.0A
Authority: CN
Inventors: C·福尔克马尔; D·考勒; D·施尼德斯
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2014-06-05
Filing date: 2015-06-05
Publication date: 2020-12-01
Anticipated expiration: 2035-06-05
Also published as: DE102014210760B4; CN105139860A; DE102014210760A1

Abstract

The invention relates to a communication device (1) for a vehicle and to a method for operating the same, wherein a first input signal (ES1) is obtained in a first listening area (HZ1) of the vehicle at a first signal detection device (MK1), said first input signal comprising a speech Signal (SP) of a speaker (S), said first input signal being transmitted to a receiver by means of a communication device (1) on the basis of an output signal (AS) of the first input signal, a current optimum value is determined for the output signal (AS) with respect to an optimization criterion, and a speech optimization indicator (3) for the speaker (S) is controlled AS a function of the optimum value, wherein the optimum value comprises a speech quality value (SOV), which is a measure of how good the speech quality of the output signal (AS) is, and a secret value (SOD), which is a measure of how good the speech signal is in the listening area (HZ2, which is spaced apart from the first signal detection device of the vehicle, HZ3, HZ4) to what extent they can be heard.

Description

Communication device and method for operating the same

Technical Field

The invention relates to a method for operating a communication device, in particular in a vehicle, and to a communication device, in particular for a vehicle, by means of which the method can be carried out.

Background

Methods for operating communication devices, in particular telephone devices, in motor vehicles have long been known. Such communication devices are usually equipped with hands-free devices and are often coupled here to a common multimedia system with other systems of the vehicle, for example for outputting radio programs, music, notifications of vehicle accessories, etc., so that the same input and output devices or loudspeakers can be used.

Making a call from a motor vehicle often has the following problems: the technical connection is not ideal. Also, the ambient noise may be relatively loud, especially when using hands-free devices. If the technical connection is too poor or the noise is too strong, this may result in the speaker no longer being heard by the interlocutor. There are many measures to improve the quality of the connection or to filter out noise as well as possible. In addition, there is an indication in the vehicle or on the telephone, whereby the user is usually indicated in the form of a bar chart how well the mobile telephone network is available. But the indication is only indicative of the technical connection quality. But the speaker is not aware of the actual speech quality, sound intensity or comprehension of his speech. In addition, speakers often unnecessarily increase speech intensity by indicating poor connection quality or by high noise. But this may not improve speech quality at all due to technical limitations. On the other hand, speakers often lose their privacy when the speech intensity is increased. In many cases, therefore, the speaker may desire to make a phone call privately, while other people around cannot hear the phone call together. In order to make a call at least somewhat secretly, the caller can use a telephone headset. In this case, at least the input signal of the interlocutor cannot be heard by other persons in the vehicle. The telephone caller in the vehicle can always hear the words, especially if he increases the sound intensity due to a lot of noise or due to a poor technical connection of the instructions.

Disclosure of Invention

The object of the present invention is to provide an improved method for operating a communication device, in particular for a motor vehicle, and a corresponding communication device, by means of which the above-mentioned problems can be at least reduced.

The object is solved by a method for a communication device operating in a vehicle, in which method a first input signal is obtained in a first listening area of the vehicle at a first signal detection means, the first input signal comprising a speech signal of a speaker, an output signal based on the first input signal is transmitted by means of the communication device to a recipient, an optimization value is determined for the output signal with respect to an optimization criterion, and a speech optimization indicator for the speaker is controlled in dependence on the optimization value, wherein the optimization value comprises a speech quality value, which is a measure of how good the speech quality of the output signal is, and a secret value, which is a measure of how well the speech signal can be heard in the listening area of the vehicle at a distance from the first signal detection means.

The object is also solved by a communication device for a vehicle, comprising at least:

a first signal detection device, which is designed to obtain a first input signal in a first listening area of the means of transport, which first input signal comprises a speech signal of a speaker;

a transmitting device configured to transmit an output signal based on the first input signal to a recipient;

a voice optimization indicator for the speaker;

an optimization value determination device which is designed to determine an optimization value for the output signal with respect to an optimization criterion and to control a speech optimization indicator for the speaker depending on the optimization value, wherein the optimization value comprises a speech quality value which is a measure of how good the speech quality of the output signal is, and a secret value which is a measure of how well the speech signal can be heard in a listening area of the vehicle which is at a distance from the first signal detection device.

Features of different embodiments may also be combined into new embodiments within the scope of the invention.

In the method according to the invention for operating a communication device, a first input signal is obtained at a first signal detection device, the first input signal comprising a speech signal of a speaker. The signal detection means may be, for example, a single microphone, preferably near the speaker, but may also be a microphone array, a directional microphone or the like, which is directed towards the speaker. It is only decisive that the speech signal of the speaker can be obtained as well as possible by the signal detection means.

An output signal based on the input signal is then transmitted to the recipient by means of the communication device. The output signal may be, for example, an input signal filtered in a suitable manner to filter as much as possible background noise and other background noise from the input signal. This output signal can therefore also be referred to as "valid signal". The communication device then transmits the output signal or useful signal in a suitable form, for example by first encoding it in a suitable manner for the transmission channel.

Preferably a mobile communication device, which is particularly preferably used in a means of transport. In this case, any means of transport, land vehicles, water vehicles and aircraft are possible. Particularly preferably a land based vehicle. In such mobile communication devices, the transmission of the output signal is typically performed via an antenna. This does not exclude that the invention is also used in stationary communication devices, which may also have, for example, cable connections or the like.

According to the invention, at least one current optimization value is now determined for the output signal prior to transmission or prior to actual transmission preparation (e.g., encoding for transmission, etc.) with respect to at least one optimization criterion. The speech optimization indicator for the speaker is then controlled according to the optimization value. An "optimization value" is understood within the scope of the present invention to mean a value which can be influenced directly or indirectly by the speaker and which should be optimized with respect to an optimization criterion. There are optimization values which are only dependent on the speaker itself, for example the sound intensity or pitch height. The optimized values that can be directly influenced by the speaker, for example by changing his voice, are referred to below as "primary optimized values". This is especially the sound intensity. There are also optimization values that are additionally related to other effects that are not based on the speaker's voice, such as background noise or the like. It is to be noted here that the speaker can of course also deal with the background noise at least to a minor extent, for example in such a way that the speaker brings his mouth closer to the microphone or even holds a hollow punch to mask the ambient noise.

Other optimized values derived from one or more such primary optimized values are referred to herein as "secondary optimized values". As will be explained later, this is a speech quality value, for example a signal-to-noise ratio or a secret value, which will be explained later, which specifies how private the speech is to be heard, or to what extent it can be heard by other persons, possibly together.

In the sense of the present invention, a "voice-optimized indicator" is understood to mean an indicator device, for example a display provided specifically for this purpose or an area on a display which is generally present, for example, for communication or multimedia devices in a vehicle. For example, a region can be used on a screen for rear seat occupants and fixed to the front seat and generally used for viewing video and/or for video telephony purposes to form such a voice-optimized indicator. For the driver, the voice-optimized indicator can indicate, for example, in the dashboard region or on a multifunction display in the vehicle center console.

In order to carry out the method, the communication device according to the invention has at least first signal detection means which are designed to obtain a first input signal which comprises a speech signal of a speaker, and transmission means which are designed to transmit an output signal based on the first input signal to a recipient. According to the invention, the communication device should have a speech optimization indicator for the speaker and at least one optimization value determination device which is designed to determine at least one optimization value for the output signal with respect to at least one optimization criterion and to control the speech optimization indicator for the speaker as a function of the optimization value.

By means of the inventive method or the inventive communication device, it is possible in a simple manner to indicate to the speaker (or user) how well his speech signal is currently suitable for enabling the recipient to correctly hear and understand the speech. Here, the voice optimization indicator is not determined as follows: what is the technical connection of the communication device to the recipient, for example, what is the current network service of the mobile telephone network. This has the advantage that the speaker is not induced to increase the volume unnecessarily, although this does not affect the quality of the speech arriving at the interlocutor at all. Instead, the "feedback" to the speaker is based solely on how good the output signal is before it is transmitted by the communication device, that is to say in a form that he can still change, perhaps by changing the sound intensity, the tone height, etc., or other measures (shielding from ambient noise). As will be explained later, in particular the following possibilities also exist: indicating to the speaker how strongly speech is perceived in its immediate surroundings. With this help group, it is possible for the speaker to optimize the optimization values, for example the sound intensity, directly or to keep them within the optimization range.

As already explained above, there are many possible optimization values.

It is particularly preferred that the at least one determined optimization value is a speech quality value, which is a measure of how good the speech quality of the output signal is. Such a speech quality value may also be referred to as a "intelligibility value" and thus it describes how clearly speech can be heard, for example in the presence of background noise. It is particularly preferred that the speech quality value represents a signal-to-noise ratio, for example of a speech signal in the received input signal.

The signal-to-noise ratio may for example particularly preferably be determined on the basis of the output signal (or on the basis of the filtered first input signal, which firstly comprises the pure speech signal to be transmitted, preferably with background signal removed) and the obtained first input signal, which comprises the speech signal and the noise. The signal-to-noise ratio can be expressed, for example, in the form of a dimensionless noise figure, which therefore describes how well the output signal is separated from the background noise or the so-called signal-to-noise ratio.

As already mentioned at the outset, it is important for many users that their speech is not heard by all passengers. It is therefore particularly preferred that the at least one optimization value may alternatively or additionally comprise a "secret value", which is a measure of how well the speech signal can be heard in a listening area at a distance from the first signal detection means. The term "spaced distance" is to be understood as meaning that the listening area is not located in the area in which the first signal detection means should detect the speech signal of the speaker, but is located next to this area or at a more distant listening area in which other persons, for example other occupants of a motor vehicle, are located and should not hear the speech clearly. These other listening zones are also referred to below as "secret zones".

Particularly preferably, for determining the secret value (which may also be referred to as a kind of "privacy index"), the first input signal may preferably be compared, after filtering, with a second input signal representing the sound in the relevant listening area. The second input signal may be received with one or more suitable sound detection units directed towards the respective listening area constituting the secret area or in the relevant secret area.

In this case, a correlation analysis can preferably be carried out in order to compare the output signal with the second input signal. The correlation analysis shows how the output signal, which first contains the speech signal that should preferably not be heard in the secret area, corresponds to the input signal corresponding to the sound signal in the relevant secret area. Orthogonal correlation functions are preferably used in the correlation analysis.

If the speech optimization indicator for the speaker is controlled by means of such a secret value or by means of an indication value based on the secret value, the speaker can directly recognize how strongly speech is perceived in his surroundings.

It can also be ensured, preferably by user initialization or automatically by means of a communication device, that a masking sound signal is output in the region of the secret region in order to improve the secret value. The automatic control of the masking sound signal may also be performed on the basis of a secret value, for example. In this case, it is ensured that the masking sound signal is transmitted in a completely targeted manner only in the region of the other listening area belonging to the secret area and as far as possible does not act as background noise in the listening area of the speaker (i.e. where the speech signal is detected). It is particularly preferred here that the masking sound signal is generated adaptively, that is to say adapted to the current situation. For outputting the masking sound signal, the communication device may preferably have a masking sound signal control means, which may for example be coupled with the optimization value determination means, such that the optimization value determination means may control the masking sound signal control means.

There are many possibilities for generating or providing a masking sound signal. In one aspect, the masking sound signal may be generated specifically with a noise generator based on a noise signal, in particular white noise. In addition, background noise already present can be detected and transmitted again, for example, with amplification or modification. The background noise may be, for example, running noise. It is particularly preferred that the masking sound signal is generated based on the signal of an audio device, such as a radio or MP3 player or the like.

Particularly preferred is, for example, an already existing background signal, for example background noise, or, particularly preferred, a signal of an audio device, which is modified in a frequency range as long as it is a masking sound signal, so that only the target speech signal is masked and the listener in the second listening area hardly notices here that the background signal has been changed at all. For this purpose, the background signal needs to be increased only slightly locally in the frequency ranges in which the current target sound signal is above the level of the background signal in the second listening area.

Furthermore, the output of the masking sound signal can only be performed when the target speech signal fully reaches or exceeds the defined minimum signal strength.

In a preferred embodiment of the invention, which other listening area is also set by the speaker as the secret area. For example, a speaker at the rear left of the rear seat of the vehicle can ensure that the passenger sitting next to him can hear the speech together, since, for example, both are on the phone, whereas a person, for example a driver, in the front region of the vehicle cannot hear the speech.

It is explicitly pointed out here that the first listening zone and the other listening zones can be freely selected in the sense of the present invention, that is to say it is entirely possible that in the first case one listening zone is the listening zone of the speaker who is just about to speak secretly by telephone, which in the other case constitutes the second listening zone, since the other person in the other listening zone is about to speak secretly by telephone.

If there are a plurality of separate listening areas, preferably each listening area is assigned an own voice optimization indicator, which is particularly preferably activated when this is the listening area of the current speaker.

There are different possibilities for constituting the voice optimized indicator. It is particularly preferred that a plurality of different optimization values are indicated on a common speech optimization indicator. This has the advantage that the user only needs to be aware of one voice optimisation indicator.

In this case, it is particularly preferred that a plurality of different optimization values are combined to form an indication value which is indicated on a common speech optimization indicator. This is particularly advantageous in the following cases: different derived or secondary optimization values (e.g. secret or privacy values on the one hand and speech quality or intelligibility values, such as signal-to-noise ratio, on the other hand) are associated with the same final primary optimization value directly related to speech, such as the speaker's sound intensity. If the influence of the primary optimization value (e.g. sound intensity) has an opposite effect on the secondary optimization values, for example if the speaker speaks more loudly, on the one hand the signal-to-noise ratio improves, but thus also the secret value decreases, it is advantageous if the indication value is generated therefrom: the indication values indicate to the speaker what the speaker is with respect to the different optimization criteria.

The combination of values also means in this sense that, for example, a common primary optimization value, for example the sound intensity, is directly indicated, preferably such that the influence on the secondary optimization value is thus simultaneously indicated together. For example, the combination of the optimization values can preferably be such that different indication levels are formed.

In a particularly preferred embodiment, a plurality of different optimization values and/or indication values combined from different optimization values are indicated in the indicator strip. For example, the indicator strip may then have different quality regions in the form of indicator levels of different colors, a certain quality region being marked or not when an indicator level is reached. Likewise, a secondary combined value, such as a sound intensity value, e.g., a bar, may also be described within a set quality level. It is particularly preferred that the indicator strip is designed such that one end of the indicator strip forms a region for the speech quality value and the other end forms a region for the secret value, since the speech quality value first becomes better and better as the sound intensity increases and the final secret value becomes worse and worse as the sound intensity increases still further.

Drawings

The invention is explained in detail below by way of example again with reference to the drawings. The attached drawings are as follows:

fig. 1 is a schematic view of an embodiment of a communication device according to the invention with four listening zones;

FIG. 2 is a block diagram of an optimization value determination device according to the embodiment of FIG. 1;

FIG. 3 is a schematic diagram of a voice optimizing indicator according to the embodiment of FIG. 1.

Detailed Description

An exemplary scenario is set out in fig. 1 and 2, respectively: the talker SP is in the first listening zone HZ1 in the rear seat of the transport means and makes a telephone call with an external interlocutor via a hands-free device in secrecy. The driver in the other listening zone HZ3 on the driver's seat should not hear the call at all. It is explicitly stated here that, in addition to this driver situation, a device constructed according to the invention also makes it possible to achieve the opposite: for example, the driver should communicate via his hands-free device and the co-riding child in the rear seat will not hear it. That is to say, the entire communication device is designed such that a person in any one of the listening zones HZ1, HZ2, HZ3, HZ4 can speak and at this point in the manner according to the invention, with the aid of the speech optimization indicator, indicate to the respective speaker how probably he can optimize his speech so that the signal reaches the interlocutor as well as possible, but is not well understood by the fellow passenger. In contrast to the illustration in fig. 1, the other occupants I can also each be assigned a voice-optimized indicator 3, which can be controlled by a common control unit 10 via the interface 30.

As shown in fig. 1, each listening zone HZ1, HZ2, HZ3, HZ4 is equipped with its own microphone MK1, MK2, MK3, MK4 and at least one of its own loudspeakers LS1, LS2, LS3, LS 4. For example, the loudspeakers LS1, LS2, LS3, LS4 may be stereo loudspeakers in the headrest of the respective position of the vehicle, thus enabling local matching. It is likewise possible to emit sound to a specific listening area by means of further loudspeakers arranged distributed over the vehicle in such a way that, by suitable superposition of the signals from the different loudspeakers, a precisely defined sound field is generated. In particular, it is also conceivable to implement more or less than four different listening zones.

In order to avoid that the signals of the loudspeakers LS1, LS2, LS3, LS4 are fed back to the microphones MK1, MK2, MK3, MK4 associated with the respective listening zones HZ1, HZ2, HZ3, HZ4, the device is provided with an echo canceller. Suitable methods and equipment for this are sufficiently known to the person skilled in the art and are therefore not explained or described further here.

Microphones MK1, MK2, MK3, MK4 are connected to input

interfaces

11, 13, 15, 17 of control unit 10, respectively. Similarly, the loudspeakers LS1, LS2, LS3, LS4 (or loudspeaker pairs) are each connected to an

output interface

12, 14, 16, 18 of the control device 10. The control device also has a bus interface 19 to the communication interface 2, which can be configured in a conventional manner and ensures that the output signal AS from the control device 10 is encoded into a suitable signal and transmitted, so that said suitable signal can be received and decoded again by the respective interface at the interlocutor. The communication interface 2 is also suitably designed to convert incoming telephone signals of a speaking person into suitable output signals and transmit them back to the control device 10, for example via the bus interface 19, which then emits corresponding signals via suitable output interfaces 12, 14, 16, 18 for controlling the loudspeakers LS1, LS2, LS3, LS4 in the listening area HZ1, HZ2, HZ3, HZ4 of the current user.

The important module of the control device 10 is here an optimization value determination device 20 which determines an optimization value for the current speech with respect to a predetermined optimization criterion in the manner according to the invention and, depending on this optimization value, controls the speech optimization indicator 3 of the current speaker S here via an interface 30 of the control device 10. As already mentioned, an example is described in fig. 1, where the speaker S is in the first listening zone HZ1, whereas in the other listening zones HZ2, HZ3, HZ4 there are other occupants, which should preferably not hear the current speech. In fig. 1, therefore, a speech optimization indicator 3 is depicted for simplicity, but without the invention being restricted thereto, also only in the first listening zone HZ 1.

Fig. 2 shows in more detail for this scenario the method or components for determining the different optimized values SOV, SOD within the optimized value determining means 20. In particular, in this scenario according to fig. 2, two optimization values SOV, SOD are determined, namely a speech quality value SOV (or intelligibility value) which specifies how good the speech quality of the output signal AS is in terms of intelligibility and a discrimination value SOD which specifies to what extent the signal is still intelligible in the other listening area. In a specific case, for example, the listening zone HZ3 of the driver can be monitored in such a way that the driver can understand the speech signal SP to what extent. The listening zones HZ2, HZ4 of other occupants may also be continuously verified in the same manner.

The manner for determining the optimum values SOV, SOD is here as follows:

for example, starting from microphone MK1 at the speaker S in the first listening zone HZ1, a first input signal ES1 is supplied via input interface 11, which preferably contains the speech signal SP of the speaker S relatively clearly. The first input signal ES1 is on the one hand passed to a filter device 21, in which all interference noise that is not correlated with speech is removed by means of a spectral filter, preferably with a high pass and a low pass and possibly also other filter stages. In this way, the useful signal or output signal AS is determined. For the purpose of adjusting the filter and determining the ambient noise, for example, a second input signal ES2 can also be used for this purpose, which is obtained from a microphone MK3 in the listening zone HZ3 via the input interface 15 of the control device. Likewise, other signals can also be acquired with other microphones (e.g., microphones MK2, MK4 in other listening zones HZ2, HZ4) and likewise used to determine background noise in order to optimize filter adjustments. If one of the other persons in the transport is a talker, this is of course reversed, whereupon the input signal obtained via the interface 11 is used to support filtering of the input signal obtained at the microphone of the respective talker.

The output signal AS is then transmitted via the bus interface 19 to the communication interface 2 (see fig. 1). In addition, the output signal AS may be utilized in the speech quality determination unit 22 in order to determine the speech quality value SOV AS the first optimized value SOV. For this purpose, the level (e.g. in db (a)) of the output signal AS is divided by the level (e.g. also in db (a)) of the first input signal ES1, whereby the signal-to-noise ratio (also referred to AS SNR-value) is obtained. The dimensionless SNR value can be scaled, for example, to a value between 0 (inaudible) and 1 (clear speech) or to other scales. As described, this signal or this value can then be used to control the voice-optimized indicator 3, as will be explained later with reference to fig. 3.

AS further shown in fig. 2, the output signal AS may be transmitted to a secret value determination unit 23, which determines the secret value SOD AS a further optimized value SOD. For this purpose, a second input signal ES2 is first used, which comes from microphone MK3 of a listening zone HZ3, which belongs to the secret area (as already explained above, here merely the listening zone of the driver by way of example). The second input signal ES2 contains mainly room noise, etc., but also a silenced speech signal SP. The level of the speech signal SP at this location is here muted proportionally to the first input signal ES1 in relation to the distance between the microphone MK1 in the listening zone HZ1 of the current talker S and the microphone MK3 from which the second input signal ES2 is derived. A correlation analysis, for example in the form of a quadrature correlation comparison, is carried out between the output signal AS and the second input signal ES2, which correlation analysis shows how many parts of the output signal AS, that is to say of the filtered first input signal ES1 and therefore of the speech signal SP, can actually be identified in the second input signal ES 2. Here, a correlation coefficient is determined, which can also be expressed, for example, as a dimensionless number, preferably between 0 and 1, (0 representing completely different and 1 representing the same). The correlation coefficient may also be transmitted as an optimization value SOD to the voice optimization indicator 3.

A preferred version of the voice optimized indicator 3 is depicted in fig. 3. In this case, a specially designed indicator strip, which, as already explained, can be depicted on a separate display or on an already existing multifunctional display or the like. The indicator bars are divided into different quality regions or indicator levels DS1, DS2, DS3, DS4, DS 5. In this case, the different indicator levels DS1, DS2, DS3, DS4, DS5 are marked or indicated with different colors.

The different end regions or the two halves of the indicator strip are assigned to different optimum values SOV, SOD as display fields, i.e. the display field DZV on the left is assigned to the speech quality value SOV (or SNR index) and the display field DZD on the right is assigned to the secret value SOD (or privacy index). It is obvious that the signal-to-noise ratio improves as the sound intensity of the speech signal SP increases. But at the same time the correlation coefficient increases, that is to say the probability of speaking secretly without being heard together by other occupants decreases.

The operation of the speech optimization indicator 3 or the indicator strip can be performed in different ways. For example, the individual indicator levels DS1, DS2, DS3, DS4, DS5 can be marked gradually, depending on the current optimization value. Alternatively, the display levels DS1, DS2, DS3, DS4, DS5 may also be marked continuously and an indicator may indicate which is the currently active display level. For example, a strip or a thread running transversely to the indicator strip can run in the direction of the arrow LS shown in fig. 3 from left to right with increasing sound intensity over the indicator levels DS1, DS2, DS3, DS4, DS 5.

The description of the markings or indicators (e.g. threads) of the indicator fields DS1, DS2, DS3, DS4, DS5 in the indicator stages DS1, DS2, DS3, DS4, DS5 can be carried out according to the following rules:

for example, if the speech quality value SOV is below a certain first speech quality limit value, a first indication level DS1 (for poor speech quality) may be reached. The second indication level DS2 is reached if the speech quality value SOV exceeds the first speech quality threshold but is still below the (higher) second speech quality threshold.

If, for example, a value between 0 (poor quality) and 1 (good quality) is determined as a speech quality value, the first speech quality limit value can be 0.4 and the second speech quality limit value can be 0.7, for example.

If the speech quality value SOV is above the second speech quality threshold value, one of the three right-hand indication levels DS3, DS4, DS5 is reached and is related to how well the secret value SOD is. If the secret value is below the first secret limit value, an intermediate indication level DS3 is reached. If the secret value SOD is higher than this first secret limit value but lower than the second secret limit value, the fourth indication level DS4 is reached and above the second secret limit value the last rightmost indication level DS5 is reached. As already mentioned, if the secret value SOD is also calculated as a value between 0 and 1, 0 means a particularly good secret (the speech signal cannot be heard in the other listening areas) and 1 means that the speech signal can be heard well in the other listening areas, so that for example the first secret limit value can be 0.4 and the second secret limit value can be 0.7. All these values are only preferred examples.

Since either the speech quality or the privacy index is very poor in the two outer indicating levels DS1, DS5, these two indicating levels DS1, DS5 are preferably marked red, for example indicating levels DS1, DS5 emit red light when the sound intensity is such that the relevant optimization value meets the above-mentioned rules of indicating levels DS1, DS 5.

The indicator stages DS2, DS4 which are then inside are just acceptable not only in terms of speech quality but also in terms of privacy index, so that both indicator stages DS2, DS4 are preferably marked yellow.

The central indicator level DS1 is an optimized area and is marked green.

If, for example, the indicator strip is controlled such that the indicator levels DS1, DS2, DS3, DS4, DS5 which satisfy the above-mentioned conditions are always lit, the speaker S only has to pay attention to the fact that the green region in the center is lit, and the speaker knows that the sound intensity is ideal, so that on the one hand at least on the transmitting side a sufficiently good speech quality is obtained before transmission to the receiver, but on the other hand the speech is not heard in the other listening area.

As is clearly visible in the preceding exemplary embodiments, the invention advantageously allows the caller to be assisted in such a way that he speaks with the necessary sound intensity, which is necessary in the case of particular noises, and the communication system is fully able to handle this sound intensity. In addition, the speaker can easily recognize whether the telephone can be heard by others in its surroundings. The method according to the invention or the communication device according to the invention is therefore of course particularly suitable for use in motor vehicles in which a plurality of persons are seated in a closed space in a closely adjacent manner. But may also be used in other similar situations such as a restroom, exposition, hall area, large office or other scene where others may hear and present many murmurs together.

It is furthermore possible by means of the invention to indicate to the speaker the quality of the speech arriving at the interlocutor, in particular with regard to sound intensity and comprehension. It is thus achieved that it is indicated to the speaker how well the interlocutor can hear the speaker's speech. If the speaker is, for example, seated in a moving vehicle and the interlocutor is a location-invariant location, it can be shown to the speaker how well he can hear on the ground side. For this purpose, the output signals transmitted to the ground side can be analyzed and evaluated accordingly and/or the quality of the speech actually arriving or transmitted there can be determined on the ground side and corresponding feedback can be transmitted to the vehicle.

By means of a corresponding indication for the speaker, it is additionally advantageously possible for the speaker not to unnecessarily increase his speech intensity, in particular if the ambient noise is strong, as otherwise the speaker would therefore run the risk of impairing his privacy of speaking. In contrast, with the invention it is achieved that the speaker speaks with a speech intensity that remains unchanged even when the ambient sound intensity is variable, if the speaker receives a signal that the speech quality is sufficiently good on the receiver side. A correspondingly sufficiently good speech quality can be achieved, for example, by means of active noise compensation techniques known per se (active noise cancellation, ANC for short), in particular by superimposing a noise signal with a correspondingly generated anti-phase signal and for generating a corresponding canceling sound on the output side.

Finally, it is pointed out again that the communication device described in the figures or the method specified only relate to an embodiment which can be modified in many respects. It is also to be noted that the use of the words "a" or "an" does not exclude the presence of a plurality of related features. Also, the term "unit" does not exclude that a unit may also be composed of several sub-units.

Claims

1. Method for operating a communication device (1) in a vehicle, in which method a first input signal (ES1) is obtained in a first listening area (HZ1) of the vehicle at a first signal detection means (MK1), which first input signal comprises a speech Signal (SP) of a speaker (S) in the first listening area (HZ1) of the vehicle, an output signal (AS) based on the first input signal is transmitted to a receiver by means of the communication device (1), an optimization value is determined for the output signal (AS) with respect to an optimization criterion, and a speech optimization indicator (3) for the speaker (S) is controlled in accordance with the optimization value, wherein the optimization value comprises a speech quality value (SOV) which is a measure of how good the speech quality of the output signal (AS) is, and a secret value (SOD) which is a measure of how good the speech quality of the speech Signal (SP) is at the listening area (HZ 2) of the vehicle at a distance from the first signal detection means, HZ3, HZ4) to what extent they can be heard.

2. The method of claim 1, wherein the speech quality value (SOV) represents a signal-to-noise ratio.

3. Method according to claim 1 or 2, characterized in that, for determining the secret value (SOD), the output signal (AS) is compared with a second input signal (ES2) representing the sound in the relevant listening area (HZ2, HZ3, HZ4) at a distance from the first signal detection means.

4. A method AS claimed in claim 3, characterized in that for comparing the output signal (AS) with the second input signal (ES2), a correlation analysis is carried out.

5. Method according to claim 1 or 2, characterized in that, for improving the secret value (SOD), a masking sound signal (MS) is emitted in the region of the relevant listening area (HZ2, HZ3, HZ4) at a distance from the first signal detection means.

6. Method according to claim 1 or 2, characterized in that a plurality of different optimization values are indicated on one common speech optimization indicator (3).

7. The method according to claim 6, characterized in that a plurality of different optimization values are combined into one indication value (DS1, DS2, DS3, DS4, DS5) which is indicated on a common speech optimization indicator (3).

8. Method according to claim 1 or 2, characterized in that a plurality of different optimization values and/or indication values (DS1, DS2, DS3, DS4, DS5) combined by a plurality of different optimization values are indicated in an indication bar.

9. Communication device (1) for a vehicle, comprising at least:

first signal detection means (MK1) which are designed to obtain a first input signal in a first listening zone (HZ1) of the vehicle, which first input signal comprises a speech Signal (SP) of a speaker (S) in the first listening zone (HZ1) of the vehicle;

a transmitting device (2) configured to transmit an output signal (AS) based on a first input signal (ES1) to a recipient;

a speech optimization indicator (3) for the speaker (S);

an optimization value determination device (20) which is designed to determine an optimization value for the output signal (AS) with respect to an optimization criterion and to control a speech optimization indicator (3) for the speaker (S) AS a function of the optimization value, wherein the optimization value comprises a speech quality value (SOV), which is a measure of how good the speech quality of the output signal (AS) is, and a secret value (SOD), which is a measure of how well the speech Signal (SP) can be heard in the listening area (HZ2, HZ3, HZ4) of the vehicle at a distance from the first signal detection device.