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

Abstract

Method for controlling communication reproduction between a hands-free device (12) in a motor vehicle (10) and a user (14), in which, for the communication reproduction, at least one loudspeaker (18) electronically coupled to the hands-free device (12) is controlled by means of a control device (16) electronically coupled to the hands-free device (12) and / or at least one sound signal (20) emanating from said at least one loudspeaker (18) is at least partially changed, comprising the method steps: - Detecting parameters for determining a vehicle usage context by means of at least one first detection device (22) electronically coupled to the hands-free device (12) - detecting a person (24) in an 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 a position (32) of the person (24) relative to the motor vehicle (10); characterized in that, during a telephone call via the hands-free device (12), the person (24) is detected in the surroundings (26) of the motor vehicle (10) depending on the parameters of the vehicle usage context, and, depending on the detected position (32) of the person (24), a volume and / or a quality of speech intelligibility of the sound signal (20) emanating from the at least one loudspeaker (18) and directed at least partially to the position (32) of the person (24) is changed by means of the control device (16).

Description

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

[0002] A hands-free system in a vehicle provides the ability to communicate or conduct a conversation without using a mobile device or cell phone. In particular, it is intended to prevent potential accidents that could arise due to the driver's inattention while holding a cell phone. Measures are provided to protect communication, for example, through the use of secure connections and noise suppression functions, as well as through the positioning of the respective components of the hands-free system.

[0003] US 201510137998 A1 discloses a motor vehicle audio system comprising an audio detector for detecting ambient noise outside a vehicle and an audio processing module for processing the ambient noise and identifying an event outside the vehicle. Depending on the event, a warning is provided to the occupant.

[0004] GB 2565518 A also discloses a noteworthy in-vehicle privacy system.

[0005] However, the problem still exists that when the hands-free system is in operation, the noise suppression from the interior of the vehicle to the surroundings of the vehicle is not sufficiently implemented to prevent third parties in the immediate vicinity of the vehicle from listening in.

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

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

[0008] A first aspect of the invention relates to a method for controlling communication playback between a hands-free device in a motor vehicle and a user. For communication playback, 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. In this case, it is provided that respective sound signals emanating from the respective loudspeakers are modified for communication playback.

[0009] In order to achieve the object of the invention and thus to provide a method by means of which noise suppression of the hands-free device from the interior of the motor vehicle into an environment of the motor vehicle is designed particularly efficiently, it is provided according to the invention to carry out a plurality of method steps described below.

[0010] In a first method step, parameters for determining a vehicle usage context are recorded by means of at least one first recording device electronically coupled to the hands-free system. Thus, during a telephone call via the vehicle's hands-free system, the vehicle usage context, for example, driving on the motorway, waiting at a red light, parking in front of an outdoor swimming pool, an open sunroof or side window, etc., is recorded via the recording device installed in the vehicle. For example, the speed and geoposition of the vehicle are also recorded when answering or making a telephone call. If the vehicle is traveling at high speed in a sparsely populated area, it can be assumed that the telephone call cannot be overheard by a random bystander, as they can only see and hear the vehicle for a short period of time.On the other hand, if a slow or stationary vehicle with the sunroof open is located near an outdoor swimming pool or market square, it can be assumed that there are many random bystanders who can listen in on the telephone conversation over a long period of time.

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

[0012] In a third step, the position of the person relative to the vehicle is detected. Thus, in addition to the potential listening context, people and their positions in the immediate vicinity of the vehicle can be detected using the second detection device.

[0013] In a fourth method step, a change in the volume and / or the quality of speech intelligibility of the sound signal emanating from the at least one loudspeaker and directed at least partially toward the person's position is provided by the control device depending on the detected position. For example, the position of a person standing in the vicinity of the motor vehicle is detected by the second detection device, and the position data is transmitted to the control device. The control device is then designed to control the respective loudspeakers, whose sound signals are at least partially directed toward the position, in such a way that the volume of these sound signals is at least partially reduced.Through these measures, the sound signals can be reduced to such an extent that the person in the vicinity of the vehicle can essentially not hear the communication playback, since a directional noise reduction is carried out depending on the position of the person.

[0014] The sound quality and volume of the sound signal generated by the loudspeaker are thus to be changed. A good speech intelligibility system should provide clear, distinct, and easily audible speech output. However, this speech output is designed to be modified depending on the person's position so that the person hears as little or as inaccurately as possible what is being output through the loudspeakers. To achieve this, the sound signals are at least partially modified in the direction of the person. In particular, this allows certain areas of the vehicle's interior to receive particularly strong sound while other areas receive particularly weak sound.The hands-free system thus has a room adjustment option by means of which the audio quality and comfort during a call and thus during communication playback are improved, in particular by adapting to the acoustic conditions of the interior.

[0015] In an advantageous embodiment of the invention, it is provided 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. In particular, the first detection device can be designed as an interior camera and the second detection device as an exterior camera, whereby respective images from the interior and images from the surroundings are captured and transmitted to the control device for analysis, wherein the control device is designed, for example, as an electronic computing device and analyzes the images using software or algorithms in order to capture the respective parameters or positions of the people in the surroundings of the motor vehicle. Depending on the captured data and parameters, the control device can implement further measures to reduce noise.For example, an exterior camera on the vehicle captures a picture of a person standing on the sidewalk to the right of a parked car. The image data is evaluated in the vehicle's electronic computer or control unit and assigned to an object class with pixel precision, using methods such as computer vision (CV). This makes it possible to recognize and locate a person in the image.

[0016] In another advantageous embodiment of the invention, it is provided that 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 designed as microphones, ADAS signal receivers, or sensor devices with motion sensors that detect the position of windows and sunroofs, the vehicle's speed, and people in the surrounding area.

[0017] In yet another advantageous embodiment of the invention, it is provided that a trajectory from a change in position of a person in the surroundings of the motor vehicle is detected by means of the second detection device. In addition to the potential eavesdropping context, persons in the immediate vicinity of the vehicle can be detected with the second detection device, which is designed, for example, as a sensor device with external sensors of the motor vehicle, in particular using additional arranged components for more efficient detection of parameters and positions, for example by means of cameras, LiDAR, radar, ultrasound, etc. It is provided that the person and the trajectory are thus detected from the change in position and that the positions of the persons, in particular in the immediate vicinity of the motor vehicle, relative to the vehicle orientation are thus determined at any time.This allows the control device to continuously control the noise reduction depending on the moving person. With an optical detection device as the second detection device, it is possible to determine the person's movement relative to the vehicle, i.e., relative to the camera orientation, which is fixed to the vehicle's orientation, from a sequence of sequentially recorded images / camera images.

[0018] An embodiment of the invention in which the control device is wirelessly coupled to a data center has also proven advantageous. This allows a potential listening context to be determined in addition to the vehicle usage context, for example, by recording data on the expected density of people at a specific location, as well as data such as the time of day, day of the week, weather, etc. This listening context can be transmitted from a central data center to the motor vehicle via a 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 a Sunday, which defines a particularly high volume of people and requires particularly strong noise reduction.

[0019] An embodiment of the invention has also proven advantageous in which a third detection device detects an additional volume and / or a further quality of speech intelligibility in the surroundings of the motor vehicle. In this case, the third detection device is designed, for example, as an external microphone or has a plurality of external microphones. The external microphones on the motor vehicle can detect the sound radiating from the inside to the outside, and the resulting sound pressure level and speech intelligibility can be recorded or determined by the scattering device or electronic computing device.For example, speech intelligibility can be measured with a subliminal STIPA test signal (Speech Transmission Index for Public Address Systems) by performing an amplitude modulation of noise in a frequency range of, for example, 125 Hz - 10 kHz and inferring or quantifying a reduced speech intelligibility from a loss of modulation depth in the recorded external microphone signal.

[0020] In addition, it has proven to be an advantageous embodiment of the invention that the sound signals are at least partially modified by the control device depending on the detected additional volume and / or the detected additional quality of speech intelligibility in the vehicle's surroundings. In particular, the hands-free system can also be controlled. The control depends on various factors, such as the type of vehicle, the hands-free system, and the user's personal settings.The control device as a volume control and / or quality control is thus controlled by the user via the steering wheel, for example. The third detection device detects the volume and / or the quality of speech intelligibility externally and transmits 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 speech intelligibility depending on the detected position or trajectory of a person in the environment. In particular, the frequency can also be controlled via an equalizer such that the sound reaching the environment is at least partially reduced. For example, frequency bands can be selectively boosted or reduced in frequency.

[0021] An embodiment of the invention has also proven advantageous in which individual users are recorded by means of a fourth recording device. The individual users of the vehicle can be identified or recorded using a variety of methods, such as image recordings from a fourth recording device designed as an interior camera. Other common methods include, for example, facial recognition using computer vision, using a personalized vehicle key as the fourth recording device, or a personal PIN code, so that the recorded data of the user or a passenger can be clearly assigned to a person. This means that physiological and driving-specific characteristic values / data in the motor vehicle, recorded via the fourth recording device installed in the motor vehicle, can be processed and assigned to an individual person.For example, the possible changes in speech intelligibility can be made dependent on the user inside, with different frequencies being changed for a young user than for an older user.

[0022] Finally, a further advantageous embodiment of the invention provides for the sound signals to be at least partially controlled by the control device depending on data from the detected individual user. By using information about the user, or driver or passenger, for example, via the fourth detection device embodied as an interior sensor, a user profile can be determined or expanded in order to make a user-dependent change to the sound signal in order to protect privacy. For example, the age or sound characteristics of the user can be queried from the user profile or approximately determined from the interior camera images, and settings to support the person can be controlled.

[0023] A second aspect relates to a hands-free device for a motor vehicle with an electronically coupled control device for controlling communication reproduction between the hands-free device and a user, which in turn is designed to at least partially control a plurality of loudspeakers electronically coupled to the hands-free device and respective volumes of the sound signals emanating from the respective loudspeakers for the communication reproduction.It is provided that parameters for determining a vehicle usage context can be detected by means of at least one first detection device electronically coupled to the hands-free device, and that a person in an environment of the motor vehicle and a position of the person relative to the motor vehicle can be detected by means of at least one second detection device electronically coupled to the hands-free device and depending on the parameters of the vehicle context, and that the volume of the sound signals emanating from the loudspeakers and at least partially directed towards the position of the person can be reduced by means of the control device and depending on the position.

[0024] For example, it is provided that the first detection device is designed as an optical detection device and / or the second detection device is designed as an optical detection device. Alternatively, it is provided that the first detection device is designed as a sensor device and / or the second detection device is designed as a sensor device. It is possible for a trajectory from a change in position of a person in the surroundings of the motor vehicle to be detected by means of the second detection device. It is also possible for the control device to be wirelessly coupled to a data center, in particular in order to detect environmental data of the surroundings. A volume in the surroundings of the motor vehicle can be detected by means of a third detection device, whereby the sound signals can be at least partially controlled by means of the control device as a function of the detected volume in the surroundings of the motor vehicle.An individual user can be detected by means of a fourth detection device, whereby the sound signals can be at least partially controlled by means of the control device depending on data of the detected individual user.

[0025] In other words, using the described method and the described hands-free system in a vehicle, it is possible to prevent external eavesdropping on conversations conducted via the hands-free system in the vehicle, or at least to reduce speech intelligibility outside the vehicle to such an extent that eavesdropping on the conversation in the immediate vicinity of the vehicle is significantly more difficult. Thus, the subject matter of the invention allows the privacy of drivers and passengers to be increased and thus the feeling of luxury in the vehicle to be enhanced through digital means (English: "digital luxury").

[0026] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0027] Showing: Fig. 1 is a first image diagram illustrating a first embodiment of a method for controlling communication reproduction between a hands-free device in a motor vehicle and a user using a data network; Fig. 2 a second image diagram illustrating a second embodiment of the method, wherein a position or trajectory of a person is detected; Fig. 3 a third image diagram illustrating a third embodiment of the method using microphones; Fig. 4 a flowchart of a possible procedure; and Fig. 5 a further flowchart of a possible further course of the procedure.

[0028] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0029] Fig. 1 shows a first image diagram to illustrate a first embodiment of a method for controlling communication reproduction between a hands-free device 12 in a motor vehicle 10 and a user 14. It is provided that by means of a control device 16 electronically coupled to the hands-free device 12, a plurality of loudspeakers 18 electronically coupled to the hands-free device 12 and respective volumes and / or qualities of speech intelligibility of the sound signals 20 emanating from the respective loudspeakers 18 for the communication reproduction are at least partially controlled and / or changed.

[0030] In a first method step S1, parameters for determining a vehicle usage context are recorded by means of at least one first recording device 22 electronically coupled to the hands-free system 12. Thus, during use of the hands-free system 12 of the motor vehicle 10, the vehicle usage context is recorded via the first recording device 22 installed in the motor vehicle 10 and / or via a further second recording device 30 arranged on the motor vehicle 10. Parameters such as those of an open sunroof near an outdoor pool or market square, or in the forest, can also be recorded.In a further second method step S2, depending on the parameters of the vehicle usage context, a person 24 in an environment 26, in particular in an immediate environment 26, of the motor vehicle 10 is detected by means of at least one second detection device 30 electronically coupled to the hands-free system 12. Thus, in addition to the vehicle usage context, a potential listening context is also determined. This listening context can depend in particular on the expected density of people 24 at a specific location and in particular on the time of day, day of the week, weather, etc. In a third method step S3, a position of the person 24 relative to the motor vehicle 10 is detected. Thus, in addition to the potential listening context, people 24 and their positions 32 in the environment 26 of the motor vehicle 10 can be detected by means of the second detection device 30.In a fourth method step S4, depending on the position 32, a change, in particular a reduction in the volume and a change in the quality of speech intelligibility of the sound signals 20 emanating from the loudspeakers 18 and at least partially directed to the position 32 of the person 24, is provided by means of the control device 16. For example, the position 32 of a person 24 standing in the environment 26 of the motor vehicle 10 is detected by means of the second detection device 30, and the resulting position data is transmitted to the control device 16. The control device 16 is now configured to control the respective loudspeakers 18, whose sound signals 20 are at least partially directed towards the position 32, in such a way that these sound signals 20 are at least partially reduced in terms of their volume and quality of speech intelligibility.By these measures, the sound signals 20 can be changed such that the person 24 in the environment 26 of the motor vehicle 10 can essentially not hear the communication reproduction, since a directed noise change and / or noise reduction and / or quality change depending on the position 32 of the person 24 is carried out by means of the method.

[0031] In particular, the Fig. 1 shows a motor vehicle 10 in which 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 camera images of a user / driver 14 are captured by the first detection device 22, which is designed as an interior camera. In addition, images of the surroundings 26 are captured by the second detection device 30, which is designed as an exterior camera. The images are transmitted to the control device 16 for evaluation, wherein the control device can be designed as an electronic computing device or can be electronically coupled to one or have one. The control device 16 thus captures the vehicle usage context and the potential eavesdropper context, as well as detects persons 24 in the immediate surroundings 26 and their position 32 relative to the vehicle.In addition, the control device 16 receives information from internal microphones 22a and external microphones 30a in order to enable possible control of the noise reduction and / or the quality change, which will be discussed in more detail in the following figures.

[0032] The control device 16 is wirelessly coupled to a data center 34. This allows a potential listening context to be determined in addition to the vehicle usage context, for example, data on the expected density of people 24 at a specific location, as well as data such as time, day of the week, weather, etc., to be recorded. This listening context can be transmitted from a central data center 34 to the motor vehicle 10 via a wireless data communication device 33.

[0033] Fig. 2 shows a second image diagram to illustrate a second embodiment of the method, wherein a position or trajectory of a person 24 is detected. The position of a person 24 or the trajectory from a change in position of a person 24 in the environment 26 of the motor vehicle 10 is detected by means of the second detection device 30, in particular using additional arranged components for more efficient detection of parameters and positions 32, for example by means of cameras, LiDAR, radar, ultrasound, etc. The provision is thus to detect the person 24 and the position or trajectory from the change in position and thus to determine the positions 32 of the people in the immediate environment 26 of the motor vehicle 10 relative to the vehicle orientation at any time. As a result, the control device 16 can continuously control the sound change depending on the stationary or moving person 24.With an optical detection device as the second detection device 30, it is thus possible to determine the movement of the person 24 relative to the motor vehicle 10, i.e., relative to the camera orientation, which is fixed to the vehicle orientation, from a sequence of sequentially recorded images / camera images. In this case, the . Fig. In the case shown in Figure 2, the driver-side loudspeakers 18a are driven louder than the other loudspeakers 18b, which are located near the person 24, in this case the passenger side and in the middle area of ​​the motor vehicle 10.

[0034] Fig. 3 shows a third image diagram illustrating a third embodiment of the method using microphones. In particular, the first detection device 22 and / or the second detection device 30 are provided as respective sensor devices, wherein the sensor devices, for example, have a respective microphone. In particular, the control device 16 thus receives information from internal microphones 22a and external microphones 30a in order to enable possible control of the noise reduction. Thus, a motor vehicle 10 is shown in which the loudspeakers 18 reproduce voice messages or telephone calls, wherein the sound signals 20 are in turn recorded outside the motor vehicle by means of the external microphones 30a and transmitted to the control device 16 for evaluation, thus also enabling a control loop.By recording sound signals A which exceed a setpoint value, the control device 16 can carry out a targeted noise reduction.

[0035] In particular, voice messages or telephone calls played back via the interior loudspeakers 18 are recorded and analyzed or speech intelligibility quantified by the control device 16. For example, the quality of an automatic transcript can be quantized during creation, for example, by statistics on the probabilities for the clear recognition of each individual word. This results in 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 means of the external microphones 30a. The values ​​of Q1 and Q2 or values ​​determined therefrom, such as the ratio of Q1 to Q2, are transmitted to the control device 16, which then controls the loudspeaker control, iethe generated audio signal or the sound signals A, changes in such a way that the conversation content can be recognized with maximum effectiveness inside the motor vehicle 10 and with minimum effectiveness outside the motor vehicle, namely in the environment 26; for example, the quotient Q1 / Q2 could be maximized for this purpose.

[0036] Fig. 4 shows a flowchart of a possible sequence of the method, which, after a start 36, makes a first query 38, which asks whether a conversation should be played back over the loudspeakers 18 of the motor vehicle 10. If the answer is "No" N and thus if the first query 38 is denied, the method is stopped via a stop command 40 and prepared for a new start 36 via a first loop 42. If the answer is "Yes" J and thus if the first query 38 is confirmed, 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 the first command 46 determines parameters as a function of the vehicle usage context from data recorded by the first detection device 22, which is designed, for example, as a sensor device.A second command 48 is intended to determine a potential listening context in which the second detection device 30, embodied as an external sensor, for example, detects environmental parameters such as weather data. The information can also be received by the data center 34, which is wirelessly coupled to the first control device 44, and taken into account for noise reduction and / or quality change. A third command 50 is now intended to determine the persons 24, in which the second detection device 30, embodied as an external sensor, for example, detects the position 32 of the person 24 in the environment 26 of the motor vehicle 10. Using a combination of the data and / or information and / or the parameters, the control device 44, embodied as an electronic computing device, can transmit a fourth command 52 to a second control device 54 in order to carry out a vehicle usage-context-dependent control 56 of the loudspeakers 18.Through these measures, the sound signals 20 can be reduced to such an extent that the person 24 in the environment 26 of the motor vehicle 10 can essentially not hear the communication playback, since a directed noise reduction and / or quality change is carried out depending on the position 32 of the person 24. Subsequently, the process is restarted at start 36 via a second loop 58.

[0037] Fig. 5 shows a further flow diagram of a possible further sequence of the method, wherein a further command 60 is provided in the first control device 44 designed as an electronic computing device, in which a quantization of a speech content recognition as in Fig. 3, and for this purpose, the data is acquired by the internal and external microphones 22a, 30a of the respective acquisition devices 14, 30. Thus, a further control 62 of the loudspeakers 18 is carried out by means of the second control device 54 in order to reduce the quality of the sound signals 20 to the outside into the environment 26, as well as the volume and quality. In the motor vehicle 10, however, the quality of the sound signals 20 should be maintained or improved. Subsequently, a further query 64 is issued, which asks whether the conversation and thus the communication playback should be ended.

[0038] If the answer is "No" N and thus the further query 64 is answered in the negative, the first control device 44, embodied as an electronic computing device, is again instructed to collect data and / or information and / or parameters via a loop 66 in order to enable a further noise reduction in the environment 26, which can be repeated at a predetermined time interval. If the answer is "Yes" Y and thus the further query 64 is confirmed, the process is restarted at start 36 via a second loop 58.

[0039] In particular, to operate the method, the hands-free device 12 for the motor vehicle 10 is provided with the electronically coupled control device 16 for controlling communication reproduction between the hands-free device 12 and the user 14, which in turn is designed to at least partially control a plurality of loudspeakers 18 electronically coupled to the hands-free device 10 and respective volumes of the sound signals 20 emanating from the respective loudspeakers 18 for the communication reproduction.In this case, parameters for determining a vehicle usage context can be detected by means of at least the first detection device 22 electronically coupled to the hands-free device 12, and the person 24 in the environment 26 of the motor vehicle 10 can be detected by means of at least the second detection device 30 electronically coupled to the hands-free device 12 and depending on the parameters of the vehicle usage context, as well as the position 32 of the person 24 relative to the motor vehicle 10. The volume of the sound signals 20 emanating from the loudspeakers 18 and at least partially directed to the position 32 of the person 24 can also be reduced by means of the control device 16 and depending on the position 32, so that a noise reduction in the environment 26 is made possible.

[0040] In other words, in the Fig. 1 to 5, in particular, three technical implementations for preventing or at least reducing speech intelligibility outside the motor vehicle 10 are described, which make it considerably more difficult to overhear a conversation of a user 14 and which can be carried out individually or in combination.

[0041] In a first implementation, the telephone call can be reproduced via the hands-free device 12 by means of a built-in sound system in the motor vehicle 10 in a context-dependent manner, so that the privacy of the user 14 is increased without particularly reducing the quality of the voice reproduction.

[0042] For this purpose, the loudspeakers 18 are controlled context-dependently during speech reproduction, as in the Fig. 2 and in the flow chart of the Fig. 4 shown.

[0043] For example, the left loudspeaker 18 can take over playback if a person 24 is located to the right of the motor vehicle 10. If the person 24 moves from the rear right to the front left, the control of the loudspeakers 18 can be gradually adjusted from the front left to the rear right in the motor vehicle 10, in line with the trajectory of the person 24. This effect can be enhanced by using special 3D audio playback formats. Furthermore, the volume of the sound signal 20 or the audio signal and the resulting glare can be temporarily reduced if the person 24 is located directly next to the motor vehicle 10.

[0044] In a second implementation, the frequency-dependent sound insulation characteristic of the motor vehicle 10, which can generally differ between motor vehicle types and equipment features, can be exploited by "pitch-shifting" (uniform change of all frequencies) or "pitch correction" (various frequency-dependent changes) of the sound signal 20 or the audio signal or by the alternative or additional use of an equalizer (combination of high-pass and low-pass filters) for filtering the sound signal 20 or the audio signal in order to reduce a quality of the speech signal in the environment 26 of the motor vehicle 10.

[0045] In particular, when the low frequencies of the sound signal 20 or the audio signal are increased, a competition arises between two different opposing effects. On the one hand, it can be exploited that higher frequencies are generally more strongly attenuated by the interior of the motor vehicle 10 than low frequencies, so that a uniform increase in these frequencies can lead to an increase in relative sound insulation. On the other hand, however, depending on the sound character of the sound signal 20 or the speech signal, low resonant frequencies can occur, which are usually perceived as subtle and significantly louder after the frequency increase. Thus, the frequency-boosted lower resonant frequencies would particularly detrimentally increase the perceived speech intelligibility outside the motor vehicle 10.

[0046] With a corresponding sound character without low resonance frequencies of the sound signal 20 or the speech signal, the low frequencies of the sound signal 20 or the audio signal can be boosted for a younger user 14, thereby actively improving the sound insulation of the motor vehicle 10 without significantly reducing the perceived speech intelligibility. Furthermore, it can be determined from the user profiles via a worn hearing aid or based on audiometry performed in the motor vehicle 10 that boosting low frequencies is only possible in a specific frequency range without excessively reducing the user's speech intelligibility.

[0047] Optionally, in order to improve speech comprehension, the change and / or alienation of the sound character, for example in dialects, accents, etc., can be compensated for by special codecs that can pitch and modify the speech in such a way that the original sound character is retained or additionally harmonized.

[0048] If, alternatively, only the low frequencies of the sound signal 20 or the audio signal are lowered, the speech comprehension inside the motor vehicle 10 is only slightly reduced, since the high-frequency audio signal components can be easily perceived, while precisely these high-frequency sound signal components or audio signal components are dampened by the sound insulation of the motor vehicle 10 in the immediate vicinity 26 of the motor vehicle 10.

[0049] A control strategy for pitch shifting or pitch correction depends accordingly on the frequency-dependent sound insulation characteristics of the motor vehicle 10, which vary relative to the sound system in the vehicle interior and the measurement position relative to the motor vehicle 10, as well as on the sound characteristics of the reproduced speech signal of a telephone call. The frequency- and direction-dependent sound insulation characteristics can be acoustically measured during the development of the motor vehicle 10, and the sound characteristics can be determined in real time from the speech signal using digital audio signal processing.

[0050] In a third implementation, by using the external microphones 30a on the motor vehicle 10, the sound signals 20 or the audio signals can be modified such that the sound signals 20 or the audio signals, especially speech, are perceived with the best possible speech intelligibility in the vehicle interior and with reduced speech intelligibility in the environment 26 of the motor vehicle 10. For this purpose, subliminal STIPA test signals or natural language processing (NLP) methods can be used, for example, to automatically convert speech content into text.

[0051] If no test signal is used, a general quality difference dG of the speech intelligibility between the interior and the surroundings 26 of the motor vehicle 10 can be determined by measuring / determining / quantifying the quality of the speech intelligibility in the interior Gl and in the exterior GA and determining the ratio, in particular a quotient of the two values ​​dG=GA / GI.

[0052] If the same method for determining the quality of speech intelligibility is applied to the sound signals 20 or audio signals reproduced in the motor vehicle 10 and the sound signals 20 or audio signals recorded in the environment 26 of the motor vehicle 10 or from the audio information recorded simultaneously by internal and external microphones 22a, 30a, the respective qualities of speech intelligibility can be determined / quantified and compared.

[0053] For example, the quality of speech comprehension can be determined from an automatic transcription of the conversation using NLP methods. In this case, the speech reproduction in the motor vehicle 10 can be improved so that the transcription is maximally poor in the surroundings and maximally good in the interior, or a weighting between the two extremes is achieved. For example, the comprehension of the conversation in the interior Gl could be weighted more heavily than the poor comprehension in the environment GA, for example, dG = GA / GI^alpha, or similar.

[0054] The quality of an automatic transcript can be quantified, for example, by creating statistics on the probabilities for the unambiguous recognition of each individual word. This results in a value Gl for the speech intelligibility quantified inside the motor vehicle 10. Simultaneously, the speech intelligibility outside the motor vehicle 10 GA is determined using external microphones 30a. The values ​​of GI and GA or values ​​determined therefrom, such as 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 the audio signal, such that the conversation content can be recognized with maximum accuracy inside the motor vehicle 10 and with minimum accuracy in the surroundings 26 of the motor vehicle 10. For example, the quotient GA / GI could be minimized using optimization methods known from the prior art, as described in Fig. 3 shown.

[0055] A motor vehicle 10 can generally be any vehicle on land, on water, or in the air. The motor vehicle 10 can therefore be a (road) motor vehicle 10, such as a passenger car, a truck, or a bus, but also an aircraft, a watercraft, an emergency vehicle 10, a construction machine, an agricultural, or a military vehicle 10. In particular, it can also be a rail-bound vehicle, such as a train, a suspension railway, a magnetic levitation train, or a capsule gliding on air cushions in a largely airless tube or floating due to magnetic forces. The user 14 can be any person in the motor vehicle 10, for example the driver, the front passenger, or other persons in a means of transport intended for the transport of people.

[0056] Furthermore, the previously described automatic improvement of the sound signal 20 or the audio signal can also be dependent on the vehicle usage and listening context as well as detected persons 24 in the environment 26 of the motor vehicle 10. For this purpose, several microphones located at different locations outside the motor vehicle 10 are used to reduce the quality of recognition of the conversation content by changing the audio signal for the external microphones 30a closest to the persons 24, as well as in the flow chart of the Fig. 5 shown.

[0057] In the foreground, a relatively high-value luxury vehicle is parked at a red light, and the driver of the relatively high-value luxury vehicle is conducting a business conversation that may contain confidential or secret information. The current vehicle usage context (stationary vehicle 10) and the potential eavesdropping context (urban area with high population density) indicate an increased need to modify the playback of the telephone conversation using the sound system installed in the vehicle 10 in such a way that the privacy of the users 14 is best protected. To this end, the low frequencies of the sound signal 20 or the audio signal are first attenuated.Since the user 14 of the motor vehicle 10 is recognized as relatively young based on the stored user profile and / or interior camera images, which were evaluated using computer-aided vision methods, his or her speech comprehension inside the motor vehicle 10 is only slightly reduced or not at all reduced, since the high-frequency audio signal components can still be easily perceived by the user 14.

[0058] In addition, by comparing the internal and external speech intelligibility, which is carried out based on internal and external microphone recordings and a quantification of the speech intelligibility quality, the reproduction properties of the audio signal are optimized such that the sound signals 20 or the audio signals, particularly speech, are perceived with the best possible speech intelligibility in the vehicle interior and with reduced speech intelligibility in the surroundings of the vehicle 10. The optimum reproduction parameters can depend, for example, on the sound characteristics of the user 14 and the other person involved in the telephone call. If a person 24 now steps next to the vehicle 10, this is detected by the vehicle sensors, and the position of the vehicle 10 and its trajectory relative to it are determined.Based on this information, the loudspeakers 18 inside can be controlled in such a way that the radiation of the sound signal 20 in the direction of this person 24 is further reduced.

[0059] In other words, the invention describes a context-dependent control of communication playback in a vehicle to protect privacy.

Claims

[1] Method for controlling communication playback between a hands-free device (12) in a motor vehicle (10) and a user (14), in which, for communication playback, at least one loudspeaker (18) electronically coupled to the hands-free device (12) is controlled by means of a control device (16) electronically coupled to the hands-free device (12) and / or at least one sound signal (20) emanating from this at least one loudspeaker (18) is at least partially modified, comprising the method steps: - Acquisition of parameters for determining a vehicle usage context by means of at least one first acquisition device (22) electronically coupled to the hands-free device (12) - Detection of a person (24) in an 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); - Determining the position (32) of the person (24) relative to the motor vehicle (10); characterized by , that during a telephone call via the hands-free device (12) the person (24) in the vicinity (26) of the motor vehicle (10) is detected depending on the parameters of the vehicle usage context and, depending on the detected position (32) of the person (24), the volume and / or the quality of speech intelligibility of the sound signal (20) emanating from the at least one loudspeaker (18) and directed at least partially towards the position (32) of the person (24) is changed by means of the control device (16). [2] Method according to claim 1, characterized by , 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] Method according to claim 1 or 2, characterized by, 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] Method according to any one of the preceding claims, characterized by , that by means of the second detection device (30) a trajectory from a change in position of a person (24) in the vicinity (26) of the motor vehicle (10) is detected. [5] Method according to any one of the preceding claims, characterized by , that the control unit (16) is wirelessly coupled to a data center (34). [6] Method according to any one of the preceding claims, characterized by , that a third detection device (36) is used to detect a further volume and / or a further quality of speech intelligibility in the vicinity (26) of the motor vehicle (10). [7] Method according to claim 6, characterized by, that the sound signals (20) are at least partially modified by means of the control device (16) depending on the detected additional volume and / or the detected additional quality of speech intelligibility in the environment (26) of the motor vehicle (10). [8] Method according to any one of the preceding claims, characterized by , that individual users (14) are recorded by means of a fourth recording device (38). [9] Method according to claim 8, characterized by , that the sound signals (20) are at least partially controlled by means of the control device (16) depending on data of the recorded individual user (14). [10] Hands-free device (12) for a motor vehicle (10) with an electronically coupled control unit (16) for controlling communication playback between the hands-free device (12) and a user (14), which in turn is configured to at least partially control a plurality of loudspeakers (18) electronically coupled to the hands-free device (12) and the respective volume levels of the sound signals (20) emitted by the respective loudspeakers (18) for communication playback, wherein parameters for determining a vehicle usage context can be detected by means of at least one 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 means of at least one second detection device (30) electronically coupled to the hands-free device (12), characterized by, that during a telephone call using the hands-free device (12) the second detection device (30) and depending on the parameters of the vehicle usage context the person (24) in the vicinity (26) of the motor vehicle (10) can be detected and depending on the position (32) of the person (24) the volume of the sound signals emanating from the loudspeakers (18) and directed at least partially towards the position (32) of the person (24) can be reduced.

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