Method for controlling communication between a hands-free device and a user in a motor vehicle, and hands-free device

Abstract

The invention relates to a method for controlling the playback of a communication between a hands-free device (12) and a user (14) in a motor vehicle (10), at least one loudspeaker (18) electronically coupled to the hands-free device (12) is controlled by a control device (16) electronically coupled to the hands-free device (12) and / or at least partially varies at least one sound signal (20) emitted from the at least one loudspeaker (18), the following method steps are provided: detecting a parameter for determining a vehicle usage situation by at least one first detection device (22) electronically coupled to the hands-free device (12); -detecting a person (24) in the environment (26) of the motor vehicle (10) by means of at least one second detection device (30) electronically coupled to the hands-free device (12) as a function of the parameters of the vehicle usage situation; -detecting a position (32) of the person (24) relative to the motor vehicle (10); and-changing, by means of the control device (16), the quality of the sound volume and / or the voice clarity of the sound signal (20) emitted from the at least one loudspeaker (18) and directed at least partially towards the position (32) of the person (24) as a function of the detected position (32).

Description

Technical Field

[0001] The invention relates to a method for controlling the playback of a communication between a hands-free device and a user in a motor vehicle according to the preamble of patent claim 1. The invention also relates to such a hands-free device. Background Art

[0002] A hands-free device in a motor vehicle provides the possibility of communicating or talking without using a mobile terminal or mobile phone. In particular, accident situations that could occur due to the driver's inattention when holding the mobile phone should be avoided. In this case, measures are provided for protecting the communication playback, for example by using a secure connection and by a noise reduction function and by the positional arrangement of the individual components of the hands-free device.

[0003] US 2015 / 0137998 A1 discloses a motor vehicle audio system, comprising an audio detector for detecting ambient noise outside the vehicle and an audio processing module for processing the ambient noise and identifying an event outside the vehicle therefrom. Based on the event, a warning is provided to an occupant.

[0004] GB 2565518 A also discloses an in-vehicle privacy system that is worth mentioning.

[0005] However, there is still the problem that the noise suppression from the motor vehicle interior into the motor vehicle environment is not sufficient to prevent third parties from eavesdropping in the immediate vicinity of the motor vehicle when the hands-free system is in operation. Summary of the invention

[0006] The object of the present invention is to provide a method and a hands-free device by means of which the noise suppression of the hands-free device from the motor vehicle interior into the motor vehicle environment is designed particularly effectively.

[0007] This object is achieved by a method according to the invention and a hands-free device according to the invention having the features of patent claim 1. Advantageous embodiments of the method according to the invention are to be regarded as advantageous embodiments of the hands-free device according to the invention, wherein the hands-free device comprises in particular means for carrying out the method steps. Advantageous developments of the invention are described by the dependent claims, the following description and the drawings.

[0008] A first aspect of the invention relates to a method for controlling the playback of a communication between a hands-free device and a user in a motor vehicle, wherein for the playback of the communication at least one loudspeaker electronically coupled to the hands-free device, in particular a plurality of loudspeakers electronically coupled to the hands-free device, is controlled by a control device electronically coupled to the hands-free device. It is proposed that the corresponding sound signal emitted by the corresponding loudspeaker for the playback of the communication is changed.

[0009] In order to achieve the object of the invention and thereby provide a method by which a hands-free device can be designed particularly effectively for noise suppression from the motor vehicle interior into the motor vehicle environment, according to the invention, it is provided that a number of method steps described below are performed.

[0010] In a first method step, it is proposed that parameters for determining the vehicle usage context are detected by at least one first detection device electronically coupled to the hands-free device. Thus, during a telephone call via the hands-free device of a motor vehicle, the vehicle usage context is determined for this purpose by the detection device installed in the motor vehicle, i.e., for example, driving on a motorway, waiting at a red light, parking in front of an outdoor swimming pool, open sunroof or side windows, etc. For example, the speed and geographical location of the vehicle are also detected when answering or conducting a telephone call. If the vehicle is driving at high speed in a sparsely populated area, it can be assumed that the telephone call cannot be heard by random bystanders, because the latter can only see and hear the vehicle for a short time. On the other hand, if the vehicle is driving slowly or stationary near an outdoor swimming pool or a market with the sunroof open, it can be assumed that there are many random bystanders who can listen to the call for a long time.

[0011] In a second method step, people in the environment of the motor vehicle, in particular in the immediate vicinity, are detected by at least one second detection device electronically coupled to the hands-free device, based on parameters of the vehicle context. Thus, in addition to the vehicle usage context, a potential overhearing context is also determined. This overhearing context can depend in particular on the expected density of people at a specific location and in particular on the time, day of the week, weather, etc. This overhearing context can be determined by the second detection device installed in the vehicle.

[0012] In a third method step, it is provided that the position of a person relative to the motor vehicle is detected. Thus, in addition to potential eavesdropping situations, the second detection device can also detect persons and their positions in the immediate vicinity of the motor vehicle.

[0013] In a fourth method step, it is proposed that the volume of the sound signal emitted from at least one loudspeaker and directed at least partially toward the position of the person and / or the quality / optimality of the speech clarity / speech intelligibility are changed by the control device as a function of the detected position. For example, the second detection device detects the position of a person standing in the motor vehicle environment and transmits the position data to the control device. The control device is then designed to control the corresponding loudspeakers whose sound signals are at least partially directed in the direction of the position in such a way that the volume of these sound signals is at least partially reduced. By these measures, the sound signals can be reduced so that the person in the vehicle environment can substantially not overhear the communication playback, because the noise reduction is performed directionally as a function of the person's position.

[0014] As a result, the sound quality and volume of the sound signal generated by the loudspeaker will be changed. A good speech intelligibility system should provide a clear, crisp and easy-to-hear speech output, but it is proposed here that this speech output is changed as a function of the person's position so that the person can hear the speech output emitted by the loudspeaker as little as possible or as inaccurately as possible. For this purpose, the direction of the sound signal towards the person is at least partially changed. Thus, in particular in certain areas in the interior of the motor vehicle the sound can be played particularly strongly, while in other areas in the interior the sound can be played particularly weakly. The hands-free device thus has a spatial adjustment possibility, by which the audio quality and comfort are improved during a call and therefore during the playback of the communication, in particular in such a way that it is adapted to the acoustic conditions of the interior.

[0015] In an advantageous design of the present invention, it is proposed that the first detection device is provided as an optical detection device, and / or the second detection device is provided as an optical detection device. Therefore, in particular, the first detection device can be configured as an internal camera, and the second detection device can be configured as an external camera, whereby the corresponding image from the interior space and the image from the surrounding environment are detected and transmitted to the control device for analysis, wherein the control device is configured, for example, as an electronic computing device, and analyzes the image by software or an algorithm to detect the corresponding parameters or positions of the person in the vehicle environment. Based on the detected data and parameters, the control device can perform further noise reduction measures. For example, the external camera of the vehicle captures an image of a person on the sidewalk on the right side of a parked motor vehicle. The image data is evaluated in the electronic computing device or the control unit of the motor vehicle and is assigned to the object category with pixel accuracy, for example using a computer-aided vision (CV) method. Therefore, the person in the image can be identified and located.

[0016] In another advantageous embodiment of the invention, the first detection device is provided as a sensor device and / or the second detection device is provided as a sensor device. For example, both detection devices can be configured as microphones, ADAS signal receivers, sensor devices with motion sensors that detect the position of windows and sunroofs, the speed of the vehicle, and people in the environment.

[0017] In another advantageous design of the present invention, it is proposed that a trajectory is detected from the position change of a person in the environment of a motor vehicle by a second detection device. In addition to potential eavesdropping situations, a second detection device, for example, which is configured as a sensor device with external sensors of a motor vehicle, can be used to detect people in the immediate environment of the vehicle, in particular by using further arranged components for more effectively detecting parameters and positions, such as by cameras, lidars, radars, ultrasound, etc. It is therefore proposed to detect people and trajectories from position changes, so that the position of the person is determined at any time, in particular the position in the immediate environment of the motor vehicle relative to the vehicle orientation. As a result, the control device can continuously perform noise reduction control according to the moving person. In the case of an optical detection device as the second detection device, the movement of the person relative to the motor vehicle, that is, the movement relative to the camera orientation, can be determined from the images / camera image sequences taken continuously in time, and the camera orientation is fixed relative to the vehicle orientation.

[0018] A design of the invention has also proven to be advantageous in which the control device is wirelessly coupled to the data center. In addition to the vehicle usage situation, potential overhearing situations can thus be determined, for example, data on the expected density of people at a certain location and data such as the time, day of the week, weather, etc. can be obtained. In this case, the overhearing situation can be transmitted from the central data center to the motor vehicle via the wireless data communication device. Thus, for example, it can be determined that the weather is good due to sunshine and high temperatures and that it is Sunday, which defines a particularly high flow of people and requires particularly strong noise reduction.

[0019] A design of the invention has also proven to be advantageous, in which another volume and / or another quality of speech intelligibility in the environment of the motor vehicle is detected by a third detection device. Here, the third detection device is configured, for example, as an external microphone or has a plurality of external microphones. The external microphone on the motor vehicle can detect the sound radiated from the inside to the outside, and the resulting sound pressure level and speech intelligibility can be recorded or determined by a scattering / diffusion device or an electronic computing device. For example, a subthreshold / over-sensory threshold STIPA test signal (“Speech Transmission Index for Public Address systems”) can be used to measure speech intelligibility by performing an amplitude modulation of the noise in a frequency range of, for example, 125 Hz-10 kHz and inferring or quantifying the reduced speech intelligibility based on the loss of modulation depth in the recorded external microphone signal.

[0020] Furthermore, it has proven to be an advantageous design of the invention that the sound signal is at least partially changed by the control device as a function of another volume detected in the environment of the motor vehicle and / or another quality of the detected speech intelligibility. In particular, it is also possible to perform an adjustment of the hands-free device. In this case, the adjustment depends on various factors, such as the type of motor vehicle, the hands-free device and the personal preferences of the user. Thus, although the control device as a volume regulator and / or quality regulator is controlled by the user, for example via the steering wheel, the third detection device detects the quality of the volume and / or speech intelligibility to the outside and sends at least one signal to the control device in order to at least partially reduce the volume and / or at least partially change the quality of the speech intelligibility according to the detected position or trajectory of the person in the environment. In particular, the frequency can also be adjusted by an equalizer so that the sound reaching the environment is at least partially reduced. For example, the frequency of the frequency band can be selectively increased or decreased.

[0021] Also advantageous is a design of the invention in which individual users are detected by a fourth detection device. Individual users of the vehicle can be identified or detected by various methods, for example by image recording from a fourth detection device configured as an interior camera. Other common methods include, for example, facial recognition by machine vision, in English "computer vision", by a personalized vehicle key as a fourth detection device, or by a personal PIN code, so that the recorded user data or passenger data can be clearly matched to an individual. Thus, the physiological and driving-specific characteristic values / data in the motor vehicle detected by the fourth detection device installed in the motor vehicle can be processed and matched to an individual. For example, possible changes in speech intelligibility can depend on the users inside, wherein the frequency of a young user changes differently from that of an elderly user.

[0022] Finally, in a further advantageous embodiment of the invention, the sound signal is at least partially controlled by the control device as a function of the detected data of the individual user. By using information about the user or driver or passenger, for example by means of a fourth detection device designed as an interior sensor system, a user profile can be determined or expanded in order to carry out user-related changes to the sound signal in order to protect privacy. For example, the age or voice characteristics of the user can be queried from the user profile or approximately determined from the interior camera image, and settings for the assistant can be controlled.

[0023] The second aspect relates to a hands-free device for a motor vehicle, comprising an electronically coupled control device for controlling the communication playback between the hands-free device and the user, and the control device is configured to at least partially control a plurality of speakers electronically coupled to the hands-free device and the corresponding volume of the sound signal for communication playback emitted from the corresponding speakers. It is proposed that at least one first detection device electronically coupled to the hands-free device can detect parameters for determining the vehicle usage context, at least one second detection device electronically coupled to the hands-free device and based on the parameters of the vehicle context can detect people in the environment of the motor vehicle and the position of the person relative to the motor vehicle, and the control device can reduce the volume of the sound signal emitted from the speaker and at least partially directed to the position of the person according to the position. For example, the first detection device is configured as an optical detection device and / or the second detection device is configured as an optical detection device. Optionally, the first detection device is configured as a sensor device and / or the second detection device is configured as a sensor device. Through the second detection device, the trajectory can be detected from the position change of the person in the environment of the motor vehicle. The control device can also be wirelessly coupled to a data center, in particular to obtain environmental data of the environment. By means of the third detection device, the volume in the environment of the motor vehicle can be detected, whereby the sound signal can be at least partially controlled by the control device as a function of the detected volume in the environment of the motor vehicle. By means of the fourth detection device, the individual user can be detected, whereby the sound signal can be at least partially controlled by the control device as a function of the detected data of the individual user.

[0024] In other words, by means of the described method and by means of the described hands-free device in a vehicle, external overhearing of a conversation conducted via the hands-free device in the vehicle can be prevented, or at least the speech intelligibility outside the vehicle is reduced so that overhearing of the conversation in the immediate vicinity of the vehicle becomes considerably more difficult. The subject matter according to the invention thus allows an increase in the privacy of the driver and passengers and thus an increase in the sense of luxury in the vehicle by digital means (English: "digital luxury"). BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further advantages, features and details of the invention are derived from the following description of preferred embodiments and from the drawings. The above-mentioned features and combinations of features mentioned in the description, as well as the features and combinations of features mentioned in the description of the drawings and / or shown alone in the drawings, can be used not only in the respective combination but also in other combinations or alone without departing from the scope of the invention.

[0026] in:

[0027] Figure 1 A first graphic representation for illustrating a first design of a method for controlling the playback of a communication between a hands-free device and a user in a motor vehicle using a data network is shown;

[0028] Figure 2 A second image diagram is shown for illustrating a second embodiment of the method, in which a position or a trajectory of a person is detected;

[0029] Figure 3 shows a third pictorial diagram for illustrating a third design of a method using a microphone;

[0030] Figure 4 a flow chart showing a possible flow of the method; and

[0031] Figure 5 A further flow chart shows a possible further sequence of the method. DETAILED DESCRIPTION

[0032] In the figures, identical elements having the same function are provided with the same reference symbols.

[0033] Figure 1 A first graphic representation is shown for illustrating a first embodiment of a method for controlling the playback of communications between a hands-free device 12 and a user 14 in a motor vehicle 10. It is provided that a plurality of loudspeakers 18 electronically coupled to the hands-free device 12 and the respective volume and / or the quality of the speech intelligibility of sound signals 20 emitted by the respective loudspeakers 18 for the playback of communications are at least partially controlled and / or varied by means of a control device 16 electronically coupled to the hands-free device 12.

[0034] In a first method step S1, parameters for determining a vehicle use context are detected by at least one first detection device 22 electronically coupled to the hands-free device 12. Thus, during the use of the hands-free device 12 of the motor vehicle 10, the vehicle use context is determined via the first detection device 22 installed in the motor vehicle 10 and / or via a further second detection device 30 arranged on the motor vehicle 10. It is also possible to record parameters such as an open sunroof near an outdoor swimming pool or a market or in a forest. In a further second method step S2, a person 24 in the environment 26 of the motor vehicle 10, in particular in the immediate vicinity, is detected by at least one second detection device 30 electronically coupled to the hands-free device 12, based on the parameters of the vehicle use context. Thus, in addition to the vehicle use context, a potential overhearing context is also determined. This overhearing context can depend in particular on the expected density of people 24 at a specific location and in particular on the time, day of the week, weather, etc. In a third method step S3, it is provided that the position of the person 24 relative to the motor vehicle 10 is detected. Thus, in addition to potential overhearing situations, the second detection device 30 can also detect a person 24 and his position 32 in the environment 26 of the vehicle 10. In a fourth method step S4, a change of the sound signal 20 emitted from the loudspeaker 18 and directed at least partially to the position 32 of the person 24 is achieved by the control device 16 as a function of the position 32, in particular a reduction in volume and a change in the quality of speech intelligibility. For example, the position 32 of the person 24 in the environment 26 of the motor vehicle 10 is detected by the second detection device 30, and the position data generated thereby are transmitted to the control device 16. The control device 16 is then configured to control the corresponding loudspeaker 18, whose sound signals 20 are directed at least partially in the direction of the position 32, so that the volume and the quality of speech intelligibility of these sound signals 20 are at least partially reduced. By these measures, the sound signal 20 can be changed so that the person 24 in the environment 26 of the motor vehicle 10 can substantially not overhear the communication playback, because a directional noise change and / or noise reduction and / or quality change is performed by the method as a function of the position 32 of the person 24.

[0035] Therefore, in particular, Figure 1A motor vehicle 10 is shown, wherein the first detection device 22 is provided as an optical detection device and / or the second detection device 30 is provided as an optical detection device, whereby a camera image of a user / driver 14 is detected by means of the first detection device 22 which is configured as an interior camera. Furthermore, an environment 26 is detected by means of the second detection device 30 which is configured as an exterior camera. The image is transmitted to a control device 16 for evaluation, wherein the control device can be configured as an electronic computing device or electronically coupled to such a device or has such a device. Thus, the control device 16 detects vehicle usage situations and potential overhearing situations and identifies persons 24 in the immediate environment 26 and their positions 32 relative to the vehicle. Furthermore, the control device 16 receives information from an interior microphone 22a and an exterior microphone 30a in order to be able to make possible adjustments to the noise reduction and / or quality changes, which will be discussed in more detail in further figures.

[0036] In this case, the control device 16 is wirelessly coupled to a data center 34. Thus, in addition to determining the vehicle usage context, potential overhearing contexts can also be determined, for example, data on the expected density of people 24 at a specific location can be obtained as well as data such as time, day of the week, weather, etc. In this case, the overhearing context can be transmitted from the central data center 34 to the motor vehicle 10 via the wireless data communication device 33.

[0037] Figure 2 A second image diagram is shown for illustrating a second design of the method, in which the position or trajectory of a person 24 is detected. In this case, the position of the person 24 or the trajectory of the position change of the person 24 in the environment 26 of the motor vehicle 10 is detected by a second detection device 30, in particular by using other arranged components for more efficient detection of parameters and position 32, for example by means of a camera, a lidar, a radar, ultrasound or the like. It is therefore proposed to detect the person 24 and the trajectory of the position or the position change, so that the position 32 of the person is determined at any time, in particular the position 32 in the immediate environment 26 of the motor vehicle 10 relative to the vehicle orientation. As a result, the control device 16 can continuously perform control of the sound changes depending on the stationary or moving person 24. Therefore, in the case of an optical detection device as the second detection device 30, the movement of the person 24 relative to the motor vehicle 10, i.e. the movement relative to the camera orientation, the camera orientation being fixed relative to the vehicle orientation, can be determined from the images / camera image sequences captured consecutively in time. Figure 2 In the case shown, the driver-side loudspeaker 18 a is controlled louder than other loudspeakers 18 b which are located in the vicinity of the person 24 , in this case the loudspeakers which are located on the passenger side and in the middle area of ​​the motor vehicle 10 .

[0038] Figure 3A third graphic representation is shown for illustrating a third embodiment of the method using a microphone. In particular, the first detection device 22 and / or the second detection device 30 are provided as corresponding sensor devices, wherein the sensor devices have respective microphones, for example. In particular, the control device 16 thus receives information from an internal microphone 22a and an external microphone 30a in order to be able to make a possible adjustment of the noise reduction. Thus, a motor vehicle 10 is shown, in which a loudspeaker 18 plays a voice message or a telephone call, and the sound signal 20 is in turn recorded outside the motor vehicle by the external microphone 30a and transmitted to the control device 16 for evaluation, whereby a control loop can be implemented. The control device 16 can perform targeted noise reduction by means of the sound signal A that is also recorded in addition to the setpoint value.

[0039] In particular, a voice message or telephone conversation played by the interior loudspeaker 18 is recorded and analyzed or the speech intelligibility is quantified by the control device 16. Thus, for example, the quality of the automatic transcription can be quantified when it is created, for example by statistics on the unambiguous recognition probability of each individual word. This gives a value Q1 for the speech intelligibility quantified in the vehicle. At the same time, the speech intelligibility outside the vehicle Q2 is determined by the external microphone 30a. The values ​​of Q1 and Q2 or the values ​​determined thereby, for example the ratio of Q1 to Q2, are transmitted to the control device 16, which then changes the control of the loudspeaker, i.e. the generated audio signal or sound signal A, so that the content of the conversation can be recognized to the greatest extent in the interior of the motor vehicle 10, while the content of the conversation can be recognized to the least extent in the area outside the motor vehicle, i.e. in the environment 26, for this purpose, for example, the quotient Q1 / Q2 can be maximized.

[0040] Figure 4A flow chart of a possible sequence of the method is shown, which after the start 36 a first query 38 is issued, in which it is asked whether the conversation is to be played through the loudspeaker 18 of the motor vehicle 10. In the case of "no" N, thus in the case of a negative first query 38, the method is stopped by a stop command 40 and provided for restarting 36 by a first loop 42. In the case of "yes" J, thus in the case of confirmation of the first query 38, three exemplary commands 46, 48, 50 are executed in a first control device 44, which is designed in particular as an electronic computing device, wherein by means of the first command 46 parameters depending on the vehicle use situation are determined from data detected by the first detection device 22, which is designed, for example, as a sensor device. By means of the second command 48, a potential overhearing situation is determined in that the second detection device 30, which is designed, for example, as an external sensor, detects environmental parameters such as weather data. Information can also be received from a data center 34 wirelessly coupled to the first control device 44 and taken into account for noise reduction and / or quality change. The person 24 is to be determined by the third command 50 in that the second detection device 30, which is designed as an external sensor, detects the position 32 of the person 24 in the environment 26 of the motor vehicle 10. By combining data and / or information and / or parameters, the control device 44, which is designed as an electronic computing device, can send a fourth command 52 to the second control device 54 in order to execute a vehicle use context-dependent actuation 56 of the loudspeaker 18. By these measures, the sound signal 20 can be reduced so that the person 24 in the environment 26 of the motor vehicle 10 is essentially unable to overhear the communication playback, because a targeted noise reduction and / or quality change is performed depending on the position 32 of the person 24. Then, by a second loop 58, the method starts again from the start 36.

[0041] Figure 5 A further flow chart shows a possible further sequence of the method, in which a further command 60 is issued in the first control device 44 designed as an electronic computing device, in which it is determined that Figure 3 The quantification of the speech content recognition is described, and wherein, for this purpose, data are detected by the internal and external microphones 22a, 30a of the corresponding detection devices 14, 30. Therefore, a further control 62 of the loudspeaker 18 is performed by the second control device 54 in order to reduce the quality and the volume and quality of the sound signal 20 entering the environment 26 to the outside. However, in the motor vehicle 10, the quality of the sound signal 20 should be maintained or improved. This is followed by another query 64, in which it is asked whether the conversation should be ended and thus the communication playback should be ended.

[0042] In the case of "No" N, and therefore in the case of a negative further query 64, the first control device 44, which is designed as an electronic computer, is again instructed to acquire data and / or information and / or parameters via a loop 66 in order to be able to repeatedly reduce the noise in the environment 26 at predetermined time intervals. In the case of "Yes" J, and therefore in the case of a confirmed further query 64, the method is restarted again from the start 36 via a second loop 58.

[0043] In particular, for the purpose of running the method, a hands-free device 12 for a motor vehicle 10 is provided with an electronically coupled control device 16 for controlling the playback of communications between the hands-free device 12 and a user 14, the control device 16 in turn being configured to at least partially control a plurality of loudspeakers 18 electronically coupled to the hands-free device 10 and the respective volumes of sound signals 20 for the playback of communications emitted from the respective loudspeakers 18. Parameters for determining a vehicle usage context can be detected here by at least a first detection device 22 electronically coupled to the hands-free device 12, and a person 24 in an environment 26 of the motor vehicle 10 and a position 32 of the person 24 relative to the motor vehicle 10 can be detected by at least a second detection device 30 electronically coupled to the hands-free device 12 and based on the parameters of the vehicle usage context. Also by means of the control device 16 and based on the position 32, the volume of the sound signal 20 emitted from the loudspeaker 18 and directed at least partially to the position 32 of the person 24 can be reduced, so that a reduction in noise entering the environment 26 is possible.

[0044] In other words, Figures 1 to 5 In particular, three technical implementations are described for preventing or at least reducing speech intelligibility outside the motor vehicle 10, which makes it quite difficult to overhear the conversation of the user 14, and these technical implementations can be implemented individually or in combination.

[0045] In this case, in a first embodiment, a telephone conversation via the hands-free device 12 can be played back in a context-sensitive manner via the built-in sound system in the motor vehicle 10, thereby increasing the privacy of the user 14 without particularly reducing the quality of the voice playback. Figure 2 Neutralization Figure 4 As shown in the flow chart of , the loudspeaker 18 is controlled in a context-dependent manner during speech playback.

[0046] Thus, for example, when person 24 is located on the right side of motor vehicle 10, left loudspeaker 18 can be responsible for the playback. If person 24 moves from the right rear to the left front, loudspeaker 18 can be actuated gradually from the left front to the right rear in motor vehicle 10 and in harmony with the trajectory of person 24. This effect can be enhanced by using special 3D audio playback formats. In addition, when person 24 is directly next to motor vehicle 10, the volume of sound signal 20 or audio signal and the resulting over-radiation / spread can be increased. Can be temporarily lowered.

[0047] In a second embodiment, the frequency-dependent sound insulation characteristics of the motor vehicle 10 - which may typically vary between motor vehicle types and equipment features - can be exploited to reduce the quality of speech signals in the environment 26 of the motor vehicle 10 by "pitch adjustment" (uniform change of all frequencies) or "pitch correction" (various frequency-dependent changes) of the sound signal 20 or audio signal, or by filtering the sound signal 20 or audio signal alternatively or additionally using an equalizer (a combination of high-pass and low-pass filters).

[0048] In particular, when the low frequencies of the sound signal 20 or the audio signal are increased, a competition between two different counteracting effects occurs. On the one hand, use can be made of the fact that generally higher frequencies are damped to a greater extent by the interior of the motor vehicle 10 than lower frequencies, so that a uniform increase of these frequencies can lead to an increase in the relative sound insulation. On the other hand, however, depending on the acoustic properties of the sound signal 20 or the speech signal, low resonant frequencies may occur, which are usually perceived subtly and become noticeably louder after the frequency increase. Therefore, a lower resonant frequency that is raised in frequency will particularly disadvantageously increase the speech intelligibility perceived outside the motor vehicle 10.

[0049] Thus, for a young user 14, the low frequencies of the sound signal 20 or audio signal can be increased without having a corresponding sound signature of the low resonant frequencies of the sound signal 20 or speech signal, whereby the sound insulation of the motor vehicle 10 is actively improved without significantly reducing the perceived speech intelligibility. Furthermore, it can be identified from the user profile by wearing a hearing aid or based on audiometry performed in the motor vehicle 10 that the increase of the low frequencies is only possible within a certain frequency range without excessively reducing the speech intelligibility of the user.

[0050] Optionally, in order to improve speech intelligibility, changes and / or alienation of sound characteristics, for example in the case of dialects, accents etc., can be compensated by special codecs which can adjust the pitch and modify the speech in such a way that the original sound characteristics are preserved or additionally harmonized.

[0051] In the alternative of reducing the low frequencies of the sound signal 20 or audio signal alone, the speech intelligibility inside the motor vehicle 10 is only slightly reduced, since the high-frequency audio signal components can be perceived very well, while it is these high-frequency sound signal components or audio signal components that are attenuated in the immediate surroundings 26 of the motor vehicle 10 by the sound insulation of the motor vehicle 10.

[0052] The adjustment strategy for "pitch adjustment" or "pitch correction" depends accordingly on the frequency-dependent sound insulation properties of the motor vehicle 10 - which vary relative to the sound system in the motor vehicle interior and relative to the measurement position of the motor vehicle 10 - and on the acoustic characteristics of the reproduced speech signal of the telephone conversation. The frequency- and direction-dependent sound insulation properties can be acoustically measured during the development of the motor vehicle 10, and the acoustic properties can be determined in real time from the speech signal by digital audio signal processing.

[0053] In a third embodiment, by using an external microphone 30a on the motor vehicle 10, the sound signal 20 or audio signal can be modified so that the sound signal 20 or audio signal, in particular speech, is perceived with the best possible speech intelligibility in the interior of the motor vehicle and with reduced speech intelligibility in the surroundings 26 of the motor vehicle 10. For this purpose, subthreshold STIPA test signals or natural language processing (NLP) methods can be used, for example, to automatically convert the speech content into text.

[0054] If no test signal is used, the general quality difference dG of speech intelligibility between the interior space of the motor vehicle 10 and the environment 26 can be determined by measuring / determining / quantifying the quality GI of speech intelligibility in the interior and the quality GA of speech intelligibility in the exterior, respectively, and determining the proportional relationship between the two values, in particular the quotient dG=GA / GI.

[0055] If the same method for determining the speech intelligibility quality is applied to a sound signal 20 or audio signal played in the motor vehicle 10 and a sound signal 20 or audio signal recorded in the environment 26 of the motor vehicle 10, or from audio information recorded simultaneously by internal and external microphones 22a, 30a, the respective qualities of speech intelligibility can be determined / quantified and compared.

[0056] For example, the quality of speech intelligibility can be determined from the automatic transcription of the conversation using NLP methods. Thus, it can be said that in this case the speech playback in the motor vehicle 10 can be improved in such a way that the transcription in the environment is the worst and the transcription in the interior is the best, or a weighting between the two extremes is achieved. Thus, for example, the intelligibility GI of the conversation in the interior may be weighted more heavily than the poor intelligibility GA in the environment, for example dG=GA / GI^alpha, etc.

[0057] The quality of the automatic transcription can be quantified, for example, by creating statistics about the unambiguous recognition probability of each word. This results in a value GI for the quantified speech intelligibility inside the motor vehicle 10. At the same time, the speech intelligibility GA outside the motor vehicle 10 is determined by the external microphone 30a. The values ​​of GI and GA or values ​​determined therefrom, for example the ratio of GI to GA, are transmitted to the control device 16, which then changes the loudspeaker control, i.e. the generated sound signal 20 or audio signal, so that the content of the conversation inside the motor vehicle 10 can be recognized as well as possible and the content of the conversation in the environment 26 of the motor vehicle 10 can be recognized as little as possible. For this purpose, for example, the quotient GA / GI can be minimized by optimization methods known in the prior art, such as Figure 3 shown.

[0058] The motor vehicle 10 can also be generally any vehicle on land, water and air. Thus, the motor vehicle 10 can be a (road) motor vehicle 10, such as a passenger car or a truck or a bus, but can also be an airplane, a ship, an emergency vehicle 10, a construction machine, an agricultural or military vehicle 10. In particular, it can also be a rail vehicle, such as a train, a levitation train, a maglev train or a cabin that slides on an air cushion or floats in a tube that is essentially airless due to magnetic forces. The user 14 can be any person in the motor vehicle 10, i.e. a driver, a passenger or other person in a transport vehicle for transporting people, for example.

[0059] Furthermore, the automatic improvement of the sound signal 20 or the audio signal described above can additionally depend on the motor vehicle use and overhearing situation and the persons 24 identified in the environment 26 of the motor vehicle 10. For this purpose, Figure 5 As shown in the flowchart of FIG. 1 , a plurality of microphones located at different positions outside the motor vehicle 10 are used so as to reduce the recognition quality of the conversation content by the change of the audio signal of the external microphone 30 a closest to the person 24 .

[0060] A relatively valuable-looking luxury car is stopped at a red light, and the driver of the relatively valuable luxury car is engaged in a business conversation, which may contain confidential or secret information in particular. The current motor vehicle usage environment (stationary motor vehicle 10) and potential eavesdropping situations (urban areas with high population density) determine that there is a higher need to modify the playback of telephone conversations by the loudspeaker installed in the motor vehicle 10 so that the privacy of the user 14 is best protected. To this end, the low frequencies of the sound signal 20 or audio signal are first reduced. Since the user 14 of the motor vehicle 10 is identified as relatively young based on the stored user profile and / or the interior camera image evaluated by computer-assisted visual methods, the intelligibility of his speech inside the motor vehicle 10 is only slightly or not reduced, because the high-frequency audio signal components can still be well perceived by the user 14.

[0061] Furthermore, by comparing the internal and external speech intelligibility based on the internal and external microphone recordings and the quantification of the speech intelligibility quality, the characteristics of the audio signal playback are optimized so that the sound signal 20 or the audio signal, in particular speech, is perceived with the best possible speech intelligibility in the interior of the motor vehicle and with reduced speech intelligibility in the environment of the motor vehicle 10. The optimal values ​​of the playback parameters can depend, for example, on the voice characteristics of the user 14 and another person participating in the telephone call. If a person 24 is now standing next to the motor vehicle 10, this is detected by the motor vehicle sensors and the position of the motor vehicle 10 and its trajectory relative to the motor vehicle 10 are also determined. Based on this information, the internal loudspeaker 18 can be controlled so that the radiation of the sound signal 20 in the direction of the person 24 is further reduced.

[0062] In other words, the present invention describes the context-dependent control of communication playback in a vehicle for privacy protection.

Claims

1. A method for controlling the playback of a communication between a hands-free device (12) and a user (14) in a motor vehicle (10), wherein for the playback of the communication at least one loudspeaker (18) electronically coupled to the hands-free device (12) is controlled by a control device (16) electronically coupled to the hands-free device (12) and / or at least partly changes at least one sound signal (20) emitted from the at least one loudspeaker (18), the method comprising the following method steps: - detecting parameters for determining a vehicle usage context by at least one first detection device (22) electronically coupled to the hands-free device (12); - detecting a person (24) in the environment (26) of the motor vehicle (10) by means of at least one second detection device (30) electronically coupled to the hands-free device (12); - detecting the position (32) of the person (24) relative to the motor vehicle (10); It is characterized in that During a telephone call via the hands-free device (12), the person (24) in the environment (26) of the motor vehicle (10) is detected based on parameters of a vehicle usage context and, based on the detected position (32) of the person (24), the volume and / or the quality of speech intelligibility of the sound signal (20) emitted from the at least one loudspeaker (18) and directed at least partially toward the position (32) of the person (24) is changed via the control device (16).

2. The method according to claim 1, It is characterized in that The first detection device (22) is provided as an optical detection device, and / or the second detection device (30) is provided as an optical detection device.

3. The method according to claim 1 or 2, It is characterized in that The first detection device (22) is provided as a sensor device and / or the second detection device (30) is provided as a sensor device.

4. The method according to any one of the preceding claims, It is characterized in that A trajectory is detected by the second detection device (30) from changes in the position of a person (24) in the surroundings (26) of the motor vehicle (10).

5. The method according to any one of the preceding claims, It is characterized in that The control device (16) is wirelessly coupled to a data center (34).

6. The method according to any one of the preceding claims, It is characterized in that A further volume and / or a further quality of speech intelligibility in the environment (26) of the motor vehicle (10) is detected by a third detection device (36).

7. The method according to claim 6, It is characterized in that The sound signal (20) is at least partially modified by the control device (16) as a function of a further volume detected in the environment (26) of the motor vehicle (10) and / or a further quality of speech intelligibility detected.

8. The method according to any one of the preceding claims, It is characterized in that The individual user (14) is detected by fourth detection means (38).

9. The method according to claim 8, It is characterized in that The sound signal (20) is at least partially controlled by the control device (16) based on detected data of the individual user (14).

10. A hands-free device (12) for a motor vehicle (10), the hands-free device comprising a control device (16) for controlling the electronic coupling of communication playback between the hands-free device (12) and a user (14), the control device being configured to at least partially control a plurality of loudspeakers (18) electronically coupled to the hands-free device (12) and the respective volumes of sound signals (20) for communication playback emitted from the respective loudspeakers (18), wherein: The invention relates to a method for detecting a parameter for determining a vehicle usage context by at least one first detection device (22) electronically coupled to the hands-free device (12), a person (24) in an environment (26) of the motor vehicle (10) and a position (32) of the person (24) relative to the motor vehicle (10) by at least one second detection device (30) electronically coupled to the hands-free device (12), It is characterized in that During a telephone call via the hands-free device (12), the person (24) in the environment (26) of the motor vehicle (10) can be detected by the second detection device (30) and based on parameters of the vehicle usage context, and the volume of the sound signal emitted from the loudspeaker (18) and directed at least partially towards the position (32) of the person (24) can be reduced based on the position (32) of the person (24).

Images