Electronic audio communication system in a motor vehicle

Abstract

The invention comprises an electronic audio system for in-vehicle communication, wherein said electronic system comprises a control unit and a plurality of pairs of loudspeakers and microphones, wherein each pair is positioned in a position close to a seat of said motor vehicle, and wherein each of said pairs of loudspeakers and microphones is positioned so that the pick-up direction of the microphone is substantially perpendicular to the sound emission direction of the corresponding loudspeaker, and wherein the control unit is configured to disable the pair of loudspeakers and microphones positioned in a position close to a seat of the motor vehicle when a safety device comprised in the motor vehicle generates a presence signal indicative of the fact that said at least one seat is not occupied by a passenger.

Description

[0001] manual

[0002] This invention relates to an electronic audio system for communication within a motor vehicle.

[0003] It is well known that passengers sitting in the back seat of a car often have difficulty hearing what passengers in the front seat are saying, and it is also difficult for front passengers to hear them, especially when music or audio is playing.

[0004] In particular, sometimes drivers have to turn around so that passengers in the back seats can hear clearly, which has an adverse impact on driving safety.

[0005] Another problem to address when designing in-vehicle electronic audio communication systems is avoiding the so-called "Larsen effect," a phenomenon that occurs when the microphone and speaker are placed too close together, triggering a sound amplification loop that leads to instability in the amplification stage and annoying noise. In reality, when sound produced by the speaker is picked up, amplified by the microphone, and then reproduced again by the speaker, a feedback loop is created, in which the sound is continuously amplified and reproduced. This loop results in a gradual increase in sound intensity and undesirably produces whistling or sharp noise.

[0006] The present invention aims to solve these and other problems by providing an electronic audio system for communication within a vehicle as described in appended claim 1.

[0007] The basic idea of ​​the invention is to employ pairs of speakers and microphones, wherein each pair is positioned close to the passenger seat and oriented such that the axes of the speaker and the associated microphone are substantially perpendicular to each other, and wherein the speaker and microphone pair is disabled based on information about the passenger actually sitting in the motor vehicle.

[0008] In addition, all microphones that are not close to the passenger currently speaking (hereinafter referred to as the first passenger) and speakers located near that passenger will also be prohibited.

[0009] To further prevent the risk of generating an echo effect (Larsen effect), at least one frequency range that may generate the echo effect is determined, preferably periodically, for example, whenever a passenger gets on or off the vehicle.

[0010] Clearly, the presence of electronic audio communication in motor vehicles facilitates conversation between front and rear passengers, while also improving driving safety.

[0011] At the same time, the Larsen effect can be prevented by taking innovative measures for the spatial and geometric positioning of microphones and speakers, and by analyzing frequencies that may generate potential echoes.

[0012] Other advantageous features of the invention will be set forth in the appended claims, which are integral to this specification.

[0013] These features and further advantages of the invention will become more apparent from the following description of some preferred embodiments thereof, one of which is illustrated in the accompanying drawings, which are provided herein as non-limiting examples only, wherein:

[0014] - Figure 1 A block diagram of an electronic audio communication system inside a motor vehicle according to the present invention is shown;

[0015] - Figure 2 It is shown that it is equipped with Figure 1 A schematic plan view of a motor vehicle with electronic systems.

[0016] In this specification, any reference to "embodiment" indicates that a particular configuration, structure, or feature is included in at least one embodiment of the invention. Therefore, expressions such as "in an embodiment" found in different parts of this specification do not necessarily refer to the same embodiment. Furthermore, any particular configuration, structure, or feature may be combined in one or more embodiments as appropriate. Therefore, the following references are used for simplicity only and should not limit the scope or extension of the various embodiments.

[0017] refer to Figure 1 The following describes an electronic audio system S for in-vehicle audio communication according to the present invention; the electronic audio system S includes a control unit 1 (i.e., electronic circuitry included in the electronic communication system), the control unit 1 including a central unit 11 for processing signals and controlling the functions of the entire electronic audio communication system. Although not shown in the figures, the electronic audio system S also includes storage devices necessary for operating the central unit. Reference numeral 12 indicates an audio output (interface) device connected to at least four speakers, indicated by reference numerals 21 to 24. Reference numeral 13 indicates an audio input (interface) device connected to at least four microphones, indicated by reference numerals 31 to 34. Reference numeral 14 indicates an interface device between the external system and the electronic circuitry 1. The interface device 14 is usable by a user of the vehicle for controlling and issuing commands to the electronic audio communication system within the vehicle, and for connecting the electronic system to calibration and setup equipment. Finally, reference numeral 247 indicates a data bus interconnecting the central unit 11, the audio output interface device 12, the audio input interface device 13, and the external interface device 14.

[0018] In other words, the electronic system S according to the present invention includes the following components:

[0019] - Control unit 1, which includes an audio output device 12 (e.g., may include a digital-to-analog converter), an audio input device 13 (e.g., may include an analog-to-digital converter, ADC), and a processing device 11 (e.g., may include a CPU, CPLD, FPGA, DSP, etc.) that communicates with the audio output device 12 and the audio input device 13.

[0020] - Multiple pairs of speakers 21-24 and microphones 31-34, wherein each pair is positioned near the seat of the motor vehicle, wherein the speakers 21, 22, 23, 24 communicate with the audio output device 12, and the microphones 31, 32, 33, 34 communicate with the audio input device 13.

[0021] When the electronic system S is in operation, the processing device 11 is configured to perform the following steps:

[0022] - Detecting the start of speech of the first passenger in the motor vehicle by at least one of the microphones 31, 32, 33, 34, for example, by executing a set of instructions implementing a speech recognition algorithm, such as a neural network trained to identify whether a person is actually talking to another person or not (e.g., when he / she is talking to himself, i.e., thinking aloud).

[0023] - Acquire a first signal representing the voice of the first passenger through the audio input device 13;

[0024] - Process the first signal to generate the second signal;

[0025] - The second signal is reproduced by at least one of the speakers, wherein at least one of the speakers 21, 22, 23, 24 is positioned closer to the second passenger who is also sitting in the motor vehicle (A), rather than closer to the first passenger.

[0026] refer to Figure 2 The following describes a motor vehicle A including an electronic system S, which preferably includes four seats S1-S4, wherein S1 is a front seat for the driver, S2 is a front seat for passengers next to the driver, S4 is a rear seat on the driver's side, and S3 is a rear seat on the opposite side of the driver.

[0027] Speakers 21, 22, 23, and 24 are from previous references. Figure 1 The speaker mentioned. Figure 2The spatial arrangement of these speakers inside the vehicle A is shown; specifically, speaker 21 is located to the left of the driver's seat S1, speaker 22 is located to the right of the front passenger seat S2, speaker 24 is located to the left of the rear seat S4 on the driver's side, and finally, speaker 23 is located to the right of the rear seat S3 on the opposite side of the driver's side.

[0028] Furthermore, the pickup direction of each of the four microphones 31 to 34 is substantially perpendicular to the sound emission direction of the four speakers 21 to 24, and the processing device 11 of the control unit 1 is also configured to disable the pair of speakers 21, 22, 23, 24 and microphones 31, 32, 33, 34 located near the seats of the vehicle A when a presence signal indicating that at least one seat is not occupied by a passenger is generated by a safety device included in the vehicle A. To detect the presence signal, the control unit 1 may include additional input devices (e.g., one or more GPIO ports, Bluetooth) that communicate with the safety device. ® (Equipment, CAN bus interface, etc.)

[0029] In practice, the sound waves emitted by the speakers are difficult for associated microphones (i.e., nearby microphones) to pick up because these sound waves will propagate in a direction perpendicular to the microphone's pickup capability, and also because any microphones that could pick up the sound waves generated by speakers 21-24 due to the absence of passengers will be disabled. This reduces the probability of the Larsen effect occurring, thus having a beneficial effect on safety when driving vehicle A.

[0030] This result can be further enhanced by using directional microphones (e.g., cardioid microphones) and directional speakers (which operate in this mode when electronic circuit 1 detects voice communication between passengers in vehicle A, rather than music playback). To this end, in a preferred embodiment, each speaker can consist of an array of smaller speakers that, under voice conditions, are driven (using in-phase and out-of-phase signals and utilizing constructive and destructive interference) to adjust their sound emission direction and produce directional sound, while under entertainment conditions they are driven to emit sound in more spatial directions.

[0031] In a preferred embodiment of the invention, the four speakers 21 to 24 are preferably mounted in a lower position within the doors of the vehicle A. Combined with the aforementioned spatial positioning of the microphones 31 to 34, this positioning reduces the risk of generating an annoying echo known as the Larsen effect. In fact, while the speakers are positioned in a lower position within the doors of the vehicle A (essentially at the same height as the seat cushion of the vehicle), the four microphones 31 to 34 are positioned higher, preferably above the head level of the vehicle occupants, mounted on the top of the vehicle and pointed towards the passengers' heads. In other words, the speakers 21, 22, 23, and 24 are located inside the vehicle A at a different height from the microphones 31, 32, 33, and 34.

[0032] This helps to further reduce the probability of the Larsen effect occurring, and also helps to reduce the probability that the driver must turn around. Therefore, it also has a positive effect on road safety when driving vehicle A.

[0033] In addition to the aforementioned spatial measures to avoid the Larsen effect, the processing device 11 of the control unit 1 is preferably configured to perform the following steps:

[0034] - Do not place microphones too close to passengers who are speaking.

[0035] - Do not place the speaker near passengers who are talking.

[0036] This helps to further reduce the probability of the Larsen effect occurring, thereby reducing the likelihood that the driver will have to turn their head while driving. Therefore, it also has a positive effect on road safety when driving vehicle A.

[0037] Furthermore, an equalizer can be applied to the audio output of the speakers to identify and attenuate any frequencies that may produce the Larsen effect. The equalizer is preferably implemented via a set of instructions executed by the processing device 11. This equalizer can be designed taking into account the structure of the vehicle A where the electronic audio communication system will be installed. In fact, the precise positioning of the speakers and microphones, their geometric arrangement and distance, and the type of sound-absorbing material used in vehicle A are all factors that can influence the occurrence of the Larsen effect.

[0038] The following procedure can be performed to configure the equalizer.

[0039] After the audio system, including the microphone and speaker to be equalized, is turned on, the equalizer can be set by means of, for example, a set of instructions that implement an audio calibration procedure, and when these instructions are executed by the processing device 11, the instructions identify and generate a gain function based on the audio response of the system (as previously determined), which defines the gain to be applied to at least one frequency component of the input signal acquired by at least one of the microphones.

[0040] It must be pointed out that special attention must be paid to adjusting the gain of the audio amplifier in the frequency range above 6-8 kHz, as these are the typical frequencies that cause the Larsen effect.

[0041] Once the specific type of problematic (critical) frequency band of the inspected vehicle A is identified, the gain of those specific frequency bands can be reduced.

[0042] More generally, the processing device 11 of the control unit 1 is also preferably configured to perform the following steps:

[0043] - Determine at least one range of critical frequencies that may produce an echo effect;

[0044] - To attenuate and / or eliminate the generation of any component of the audio output signal (second signal) falling within the range of the critical frequency, thereby preventing echo effects.

[0045] In this way, the audio signal can be equalized to avoid the Larsen effect, thereby reducing the probability that the driver must turn around while driving vehicle A. This will have a beneficial effect on the safety of driving vehicle A.

[0046] More specifically, the processing device 11 can also be configured to determine at least one range of critical frequencies that may produce an echo effect based on the spatial arrangement of pairs of speakers 21, 22, 23, 24 and microphones 31, 32, 33, 34 inside the vehicle A. This method has proven particularly advantageous because it allows the system to be calibrated during the development of the vehicle A or when significant modifications are made to the passenger compartment of the vehicle A in any way (e.g., installation of the control unit 1 and microphones 31-34 and optional speakers 21-24, addition or removal of seats, etc.), thereby further reducing the probability of the Larsen effect occurring and reducing the probability that the driver needs to turn around to talk to rear passengers while driving. This also has a positive effect on road safety when driving the vehicle A.

[0047] As an alternative to the above solution, the processing device 11 can also be configured to perform the following steps:

[0048] - Generates an audio excitation signal with energy concentrated in at least one frequency range;

[0049] - The audio signal whose energy is concentrated through at least one of the speakers;

[0050] - Acquire feedback audio signals through at least one of the microphones 31, 32, 33, and 34;

[0051] - Based on the feedback signal, determine at least one range of critical frequencies that may produce an echo effect.

[0052] This method has proven particularly advantageous because it allows the system to be calibrated whenever any changes occur in the passenger compartment of vehicle A that alter its acoustic characteristics (e.g., when someone gets on or off the vehicle, or when seats are adjusted). This further reduces the probability of the Larsen effect and the likelihood of the driver needing to turn around to talk to rear passengers. This also has a positive effect on road safety when driving vehicle A.

[0053] This equalizer calibration operation can be performed periodically in real time by the processing device 11, especially if the data processing speed of the processing device 11 is high enough to identify and attenuate any frequencies that may produce the Larsen effect in just a few milliseconds. In this case, the transmission of the output signal to each speaker may be delayed, the delay being the time required for the equalizer to intervene. Therefore, the equalizer will operate dynamically, thereby making driving vehicle A safer.

[0054] Another effective measure to prevent the Larsen effect includes inserting a device into the amplification chain that produces a barely perceptible “vibrato” by slightly and cyclically raising and lowering frequencies across the entire processed spectrum, thereby preventing signals from the speaker from entering the microphone at the same frequency or phase.

[0055] It should be noted that when the speakers amplify sound from the audio entertainment system rather than the passengers' voices, an equalizer calibrated for that particular vehicle or a device that produces a "vibrato" effect is not used.

[0056] In other words, the processing device 11 is preferably configured to generate the second signal by shifting the frequency of the first signal. That is, it is configured to generate the second signal by performing a convolution operation in the time domain between the first signal (acquired by at least one of the microphones 31-34) and a sinusoidal signal, the frequency of which is equal to the frequency value of the first signal to be shifted in the frequency domain (preferably in the range of 0.5 to 10 Hz). This helps to further reduce the risk of the Larsen effect, while also reducing the likelihood that the driver will need to turn around to talk to rear passengers while driving. This will also have a positive effect on road safety when driving vehicle A.

[0057] It must be pointed out that by programming the control unit 1 through the interface device 14, and specifically calibrating the system for each motor vehicle A, electronic measures to prevent the Larsen effect can be effectively implemented.

[0058] According to another advantageous embodiment of the invention, the processing apparatus of the electronic audio system is configured to detect ambient noise around one of the microphones and to apply a noise cancellation algorithm to a captured signal representing the speech of a first passenger beginning to speak, captured by at least one microphone. In this way, noise around the speaking passenger is detected and eliminated before any amplification is applied, thereby improving the listening experience for the remaining passengers.

[0059] In addition to one of the embodiments described above, the processing device is configured to detect loud noises, crying sounds, screams, or high-pitched noises originating from one of the microphones, and is configured to prevent the reproduction of such interfering sounds through at least one of the speakers. According to this embodiment, the reproduction of such interfering sounds, which are particularly likely to distract or startle the driver and thus lead to dangerous driving maneuvers, is prevented from being reproduced as output signals through the speakers. Detection of loud noises, crying sounds, screams, or high-pitched noises can be achieved by setting corresponding frequency bands for these interfering sounds. The prohibited frequency bands are preferably one of the following: 300Hz-600Hz, 30Hz-150Hz, around 2kHz, or higher.

[0060] According to another advantageous embodiment of the invention, the processing device is configured to receive input parameters via an interface device. These input parameters are suitable for setting the detection sensitivity level of at least one of the microphones and / or for setting the energy level of at least one reproduced second signal via the speaker. The input parameters particularly consider passenger composition, such as “family,” “business,” “taxi,” “tourism,” “sleep,” “telephone call,” “front row conversation,” “rear row conversation,” “rear row children,” etc. Based on using the aforementioned keywords as input parameters, acquisition via the microphones and / or reproduction via the speakers can be set. This setting is performed in such a way that, according to the set parameters, activation and / or deactivation of at least one microphone and / or at least one speaker is performed. The purpose of activation and / or deactivation is to assign speaking and / or listening subgroups to passengers seated in different positions within the vehicle. These subgroups are particularly characterized by front row conversation groups, rear row conversation groups, or conversation groups covering all passengers (including or excluding the driver). Therefore, a subgroup can in particular be one of the following: all passengers including the driver, all passengers including the driver, front seat passengers, rear seat passengers, rear seat passengers excluding the left rear seat passenger, rear seat passengers excluding the right rear seat passenger, etc. Clearly, the aforementioned subgroup configuration capability is not limited to vehicles with two rows of seats, but can be arbitrarily extended to vehicles with more than two rows of seats.

[0061] Some possible variations of the invention have been described above, but it will be clear to those skilled in the art that other embodiments can be implemented in practice, wherein some elements may be replaced by other technically equivalent elements. Therefore, the invention is not limited to the illustrative examples described above, but various modifications, improvements, or substitutions can be made to equivalent parts and elements without departing from the basic inventive concept as set forth in the following claims.

Claims

1. An electronic audio system (S) for communication within a motor vehicle (A), comprising: - Control unit (1), which includes an audio output device (12), an audio input device (13), and a processing device (11) that communicates with the audio output device (12) and the audio input device (13). - Multiple pairs of speakers (21,22,23,24) and microphones (31,32,33,34), among which, Each pair is configured to be positioned near the seats (P1, P2, P3, P4) of the motor vehicle (A), wherein the speakers (21, 22, 23, 24) communicate with the audio output device (12), and the microphones (31, 32, 33, 34) communicate with the audio input device (13). The processing device (11) of the control unit is configured as follows: - The first passenger in the motor vehicle begins to speak upon detection of at least one of the microphones (31, 32, 33, 34). - Acquire a first signal representing the voice of the first passenger through the audio input device (13). - Process the first signal to generate the second signal. - The second signal is reproduced by at least one of the speakers, wherein at least one of the speakers (21, 22, 23, 24) is positioned closer to the second passenger also seated in the motor vehicle (A), rather than closer to the first passenger. In this configuration, each pair of speakers (21, 22, 23, 24) and microphones (31, 32, 33, 34) is positioned such that the pickup direction of the microphone is substantially perpendicular to the sound emission direction of the corresponding speaker, and the processing device (11) of the control unit (1) is further configured to... - When the safety equipment included in the motor vehicle (A) generates a presence signal indicating that the seat is not occupied by a passenger, the pair of speakers (21,22,23,24) and microphones (31,32,33,34) located near at least one seat of the motor vehicle are prohibited.

2. The electronic system (S) according to claim 1, wherein, The processing device (11) of the control unit (1) is further configured to - Microphones that are not positioned close to the first passenger are prohibited. - Speakers should not be placed near the first passenger.

3. The electronic system (S) according to claim 1 or 2, wherein, The processing device (11) of the control unit (1) is further configured to - Determine at least one range of critical frequencies that may produce an echo effect, and - Based on the at least one determined frequency range, attenuation and / or elimination are performed on any component of the second signal falling within the critical frequency range, thereby preventing the echo effect.

4. The electronic system (S) according to claim 3, wherein, The processing device (11) is configured to determine at least one range of critical frequencies that may produce an echo effect based on the spatial arrangement of pairs of speakers (21,22,23,24) and microphones (31,32,33,34) inside the motor vehicle (A).

5. The electronic system (S) according to claim 3, wherein, The processing device (11) is also configured to - Generates an audio excitation signal with energy concentrated in at least one frequency range. - The audio signal with concentrated energy emitted by at least one of the speakers (21, 22, 23, 24) - Acquire feedback audio signals via at least one of the microphones (31, 32, 33, 34). - Determine at least one range of critical frequencies that may produce an echo effect based on the feedback signal.

6. The electronic system (S) according to any one of claims 3 to 5, wherein, The processing device (11) of the control unit (1) is further configured to cyclically perform the steps of determining at least one range of critical frequencies and attenuating and / or eliminating those components of the audio output signal that fall within the range of critical frequencies.

7. The electronic system (S) according to any one of claims 1 to 6, wherein, Each speaker (21,22,23,24) in the speaker (21,22,23,24) and microphone (31,32,33,34) pair is located at a different height than the microphone associated with the pair (31,32,33,34).

8. The electronic system (S) according to any one of claims 1 to 7, wherein, The processing device (11) is configured to cyclically generate the second signal by offsetting the frequency of the first signal.

9. The electronic system (S) according to any one of claims 1 to 8, wherein, The processing device (11) is configured to detect ambient noise surrounding one of the microphones (31, 32, 33, 34) and apply a noise cancellation algorithm to the first signal representing the voice of the first passenger.

10. The electronic system (S) according to any one of claims 1 to 9, wherein, The processing device (11) is configured to detect loud noises, crying sounds, screams or high-pitched noises originating from one of the microphones (31, 32, 33, 34) and is configured to prevent the reproduction of these sounds by the at least one of the speakers (21, 22, 23, 24).

11. The electronic system (S) according to any one of claims 1 to 10, wherein, The processing device (11) is configured to receive input parameters via an interface device (14) for setting the sensitivity level of the detection of the microphone (31,32,33,34) and / or for setting the energy level of the reproduction level of the second signal via at least one of the speakers (21,22,23,24).

12. The electronic system (S) according to any one of claims 1 to 11, wherein, The processing device (11) is configured to receive input parameters through the interface device (14) for setting at least one subgroup across predetermined passenger locations to activate and / or deactivate at least one of the microphones (31, 32, 33, 34) and / or at least one of the speakers (21, 22, 23, 24).

13. A vehicle equipped with one of the electronic systems (S) according to any one of claims 1 to 12.

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