WO2026013008A1

WO2026013008A1 - System and method for functional safety validating an output of an audio message in an interior of a vehicle

Info

Publication number: WO2026013008A1
Application number: PCT/EP2025/069358
Authority: WO
Inventors: Gerhard Dochow
Original assignee: Aumovio Germany GmbH
Current assignee: Aumovio Germany GmbH
Priority date: 2024-07-09
Filing date: 2025-07-08
Publication date: 2026-01-15
Anticipated expiration: 2027-01-09
Also published as: DE102024207834A1; DE102024207833A1; WO2026013021A1; WO2026013022A1; WO2026013005A1; DE102024207836A1; DE102024207838A1; DE102024207835A1; WO2026013006A1; DE102024207839A1; WO2026013024A1; WO2026013010A1; DE102024207837A1

Abstract

A system and a method for validating an output of an audio message in an interior of a vehicle is provided. A signal power modulator modulates said audio message using an audio frequency spectrum of said audio message as carrier frequency and predetermined modulation data. An audio generator outputs a speaker sound corresponding to said modulated audio message using one or more speakers in said interior. An audio recorder receives a vehicle sound using one or more microphones in said interior and outputs a vehicle signal, corresponding to said received vehicle sound. An extracting unit extracts estimated modulation data from said vehicle signal. A validation unit determines a difference between said estimated modulation data and said predetermined modulation data and validates an output of said audio message when said difference is below a predetermined threshold.

Description

SYSTEM AND METHOD FOR FUNCTIONAL SAFETY VALIDATING AN OUTPUT OF AN AUDIO MESSAGE IN AN INTERIOR OF A VEHICLE

BACKGROUND

A multimedia system of vehicle may provide an audio message to the driver or other passengers of that vehicle. The audio message may be a warning or an instruction message for the driver or for the other passengers. However, due to circumstances (e.g., a broken speaker) this message may not reach the passengers of the vehicle in good order. Therefore, it may be important to validate the delivery of the safety message to interior where the passengers are seated. In case the message was not delivered in good order, the message may be generated again, for example, as a visual message or, again, as an audio message.

The objective of the invention is therefore to provide a system and a method for functional safety validating an output of an audio message in an interior of a vehicle.

SUMMARY

The objective of the invention is met by providing a system according to claim 1 and a method according to claim 8.

According to a first aspect a system for functional safety validating an output of an audio message in an interior of a vehicle is provided, wherein the system comprises: a signal power modulator audio generator audio recorder extracting unit validation unit wherein the signal power modulator is arranged for: receiving an audio message having an audio spectrum of at least one or more audio frequencies with an amplitude greater than a minimum value and with any phase; modulating said audio message using said audio spectrum as carrier frequencies and predetermined modulation data for said audio message; outputting a modulated audio message to said audio generator, outputting said audio message to said extracting unit and outputting said predetermined modulation data to said validation unit; wherein the audio generator is arranged for: receiving said modulated audio message; outputting a speaker sound corresponding to said modulated audio message using one or more speakers in said interior of said vehicle; wherein the audio recorder is arranged for: receiving a vehicle sound using one or more microphones in said interior of said vehicle; outputting a vehicle signal corresponding to said received vehicle sound to said extraction unit; wherein the extracting unit is arranged for: receiving said vehicle signal and said audio message; extracting estimated modulation data from said vehicle signal using said audio message; outputting said estimated modulation data to said validation unit, wherein said validation unit is arranged for: receiving said estimated modulation data and said predetermined modulation data; determining a difference between said estimated modulation data and said predetermined modulation data; validating an output of said audio message when said difference is below a predetermined threshold; outputting validation data corresponding to said validation.

The wording “functional safety validating” may refer to determining that a safety message has been delivered, i.e. that the function of the audio message of providing information to the driver of the vehicle has been executed. Furthermore, the volume of the delivered audio message should be such that the driver should be able to understand the information comprised in the audio message. Therefore, the volume should be above a certain minimum volume and above the volume of other sounds around the driver.

According to the invention, the audio message comprises an audio spectrum of at least one or more audio frequencies with an amplitude greater than a minimum value and with any phase. In other words, amplitudes of the one or more audio frequencies may be the same, but must all be above a predetermined minimum value, and the phases of the one or more audio frequencies may have an arbitrary value.

In one or more embodiments, the audio message may comprise one or more tones each with an audio frequency. In one or more embodiments, the audio message may comprise one or more spoken words.

The system according to the invention comprises a signal power modulator, an audio generator, an audio recorder, an extracting unit and a validation unit. These may be separate devices, separate processors on a PCB, or separate programs running on a single processor.

In one or more embodiments, the audio message is received by the signal power modulator from a memory that is comprised in the system. In one or more other embodiments, the audio message is received by the signal power modulator from a server that is located outside the vehicle, for example over a wireless connection.

In one or more embodiments, the signal power modulator may be located outside of the vehicle and said modulation may take place outside the vehicle and/or may take place in advance of the need to output the audio message, for example before the vehicle is produced. The signal power modulator may then provide the modulated audio message, the audio message and the predetermined modulation to the vehicle, where these are recorded for use later.

According to the invention the audio message is modulated with all or parts of its audio frequencies as carrier frequencies and a predetermined modulation data for said audio message.

In one or more embodiment, all frequencies of the audio message above the highest frequency of the predetermined modulation data are used for the demodulation. This is further explained in the detailed description section of this document.

Because of this modulation, the results of the validation are more accurate and less sensitive to disturbances and interference (which normally do not correlate with the audio message) than the results of many systems known in the art. Furthermore, the system is able to correctly validate the output of the audio message using a shorter period of audio samples than many systems known in the art. In one or more embodiments, different audio messages may be modulated with predetermined modulation data. For each audio message, the predetermined modulation data may be retrieved from a memory that is comprised in the system or is received by the signal power modulator from a server that is located outside the vehicle, for example over a wireless connection.

The audio generator receives the modulated audio message from the signal power modulator and uses one or more speakers in vehicle to convey the audio message to the driver and other passengers in the vehicle.

In order to determine what the passenger would be able to hear, the audio recorder may use one or more microphones to receive a vehicle sound. This vehicle sound may comprise the speaker sound and other sounds from the vehicle itself (e.g. the engine), from the passengers speaking, and/or from outside the vehicle. The speaker sound may be distorted in the vehicle by reflections or echoes of the speaker sound and/or malfunctioning of the one or more speakers in the vehicle.

The extraction unit receives a vehicle signal corresponding to the received vehicle sound from the audio recorder and extracts estimated modulation data from the vehicle signal using the audio message, which is received from the signal power modulator. It may be noted that the extraction unit is not provided with the modulated audio message and is advantageously able to extract estimated modulation data from the vehicle signal without using the modulated audio message.

The estimated modulation data is used by the said validation unit to determine a difference between the estimated modulation data and said predetermined modulation data received from the signal power modulator. This difference may indicate how well the audio message could have been heard by the passengers, wherein a smaller difference indicates a better conveying of the audio message.

Based on this difference the validation unit determine whether the conveying of the audio message fulfills one or more requirements for conveying a safety message, i.e. the difference is below a predetermined threshold. In that case the output of the audio message may be considered validated. The validation unit outputs validation data that indicates the results of the validation. The predetermined modulation data may correspond to many different ways of modulating a signal or a combination of those:

- In one or more embodiments, the predetermined modulation data correspond to a modulation frequency.

- In one or more embodiments, the predetermined modulation data correspond to (i) periodical modulation data corresponding to a periodical modulation and/or (ii) non-periodical modulation data corresponding to a non-periodical modulation. An advantage of this combination is that a periodical modulation may be helpful to extract estimated modulation data from the vehicle signal.

- In one or more embodiments, the predetermined modulation data correspond to pause data corresponding to modulation pauses. Modulation pauses may be applied in time-periods wherein the sound power of the audio message is too low for being properly received by the audio recorder. Advantages of using modulation pauses may be that (i) a low sound power does not contribute to a non-validation and that (ii) modulation pauses may be characteristic for the audio message and thus may be used for the validation.

In one or more embodiments, the signal power modulator is further arranged for determining a minimum sound power for modulated audio message during a predetermined power period and for outputting minimum sound power data, corresponding to said minimum sound power, to said validation unit. The extracting unit may be further arranged for extracting an estimated sound power of said vehicle sound during said predetermined power period using said vehicle signal and for outputting estimated sound power data, corresponding to said estimated sound power, to said validation unit, wherein said validation unit is further arranged for receiving said estimated sound power data and said minimum sound power data and validating the output of said audio message when said estimated sound power is equal to or higher than said minimum sound power.

An advantage of this embodiment may be that it introduces another requirement for the outputting of the audio message: the sound level of the audio message. This should be above a minimum level otherwise the passengers cannot be expected to have heard the audio message. In one or more embodiments, the extracting unit may be further arranged for storing an inverse audio transfer function for said interior and determining an estimated audio signal based on the vehicle signal and said audio message using the inverse audio transfer function.

The inverse audio transfer function may indicate how a sound from the speakers in interior the vehicle is distorted before it is recorded by the microphones in interior of the vehicle, wherein the distortion is caused by reflections in interior and/or attenuation in the air of the interior. This inverse audio transfer function may be specific and/or determined for a specific vehicle model. The use of an inverse audio transfer function may improve the extraction of the estimated modulation data.

The extracting unit may be further arranged for demodulating said estimated audio signal using said audio message, and optionally for filtering the demodulation results using a band filter, in order to obtain an estimated demodulated audio signal. The band filter may pass a frequency range which comprises modulation frequencies used for said modulation. The extracting unit may be further arranged for extracting estimated modulation data from said estimated demodulated audio signal.

In one or more embodiments, the extracting unit is further arranged for extracting estimated periodical modulation data from said estimated demodulated audio signal, wherein said estimated modulation data comprises said estimated periodical modulation data or is extracted using said estimated periodical modulation data.

An advantage of using estimated periodical modulation data may be that it can be used as an input for the extraction of the non-periodical modulation data and/or as an input for the validation, whereby the estimated periodical modulation data is part of the estimated modulation data.

In one or more embodiments, the extracting unit is further arranged for extracting estimated pause data from said estimated demodulated audio signal, wherein said estimated modulation data comprises said estimated pause data or is extracted using said estimated pause data.

An advantage of using estimated pause data may be that it can be used as an input for the extraction of the periodical and/or non-periodical modulation data, and/or as an input for the validation whereby the estimated pause data is part of the estimated modulation data.

In one or more embodiments, the system according to the invention may be embodied in a multimedia system of a vehicle. According to another aspect of the invention is vehicle is provided that comprises a system for functional safety validating an output of an audio message according to any of embodiments discussed in this document.

According to yet another embodiment, a method for functional safety validating an output of an audio message in an interior of a vehicle is provided, wherein the method comprises the steps of: receiving an audio message having an audio spectrum of at least one or more audio frequencies with an amplitude greater than a minimum value and with any phase; modulating said audio message using said audio frequency spectrum as carrier frequencies and predetermined modulation data for said audio message; outputting a speaker sound corresponding to said modulated audio message using one or more speakers in said interior of said vehicle; receiving a vehicle sound using one or more microphones in said interior of said vehicle; generating a vehicle signal corresponding to said received vehicle sound; extracting estimated modulation data from said vehicle signal using said audio message; determining a difference between said estimated modulation data and said predetermined modulation data; validating an output of said audio message when said difference is below a predetermined threshold; generating validation data corresponding to said validation.

In one or more embodiments, said predetermined modulation data correspond to a predetermined modulation frequency; and/or said predetermined modulation data comprise: a. periodical modulation data corresponding to a periodical modulation of said audio message; and, b. non-periodical modulation data corresponding to a non-periodical modulation of said audio message; and, preferably, c. pause data corresponding to modulation pauses, wherein a modulation pause is an absence of modulation in a predetermined time-period, wherein preferably a sound power of said audio message is below a predefined threshold.

In one or more embodiment, the method further comprises the steps of: determining a minimum sound power for modulated audio message during a predetermined power period; generating minimum sound power data, corresponding to said minimum sound power, to said validation unit; extracting an estimated sound power of said vehicle sound during said predetermined power period using said vehicle signal; generating estimated sound power data, corresponding to said estimated sound power, to said validation unit, validating the output of said audio message when said estimated sound power is equal to or higher than said minimum sound power.

In one or more embodiment, the method further comprises the steps of: determining an estimated audio signal based on the vehicle signal and said audio message using the inverse audio transfer function; demodulating said estimated audio signal using said audio message, and optionally for filtering the demodulation results using a band filter, in order to obtain an estimated demodulated audio signal, wherein said optional band filter passes a frequency range which comprises modulation frequencies used for said modulation; and, extracting estimated modulation data from said estimated demodulated audio signal.

In one or more embodiment, the method further comprises the step of: extracting estimated periodical modulation data from said estimated demodulated audio signal, wherein said estimated modulation data is extracted using said estimated periodical modulation data.

In one or more embodiment, the method further comprises the step of extracting estimated pause data from said estimated demodulated audio signal, wherein said estimated modulation data comprises said estimated pause data.

According to another aspect of the invention a computer program is provided, wherein said computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method of according to any of the embodiments described in this document. Furthermore, a computer-readable medium is provided having stored thereon said computer program.

The working, advantages and embodiments of the method and the vehicle as well as the working, advantages and embodiments of the computer program and computer-readable medium, correspond with the working, advantages and embodiments of the method as described in this document, mutatis mutandis.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference in the following description is made to the accompanying drawings in which:

Figure 1 shows a schematic overview of a system for functional safety validating an output of an audio message in an interior of a vehicle according to one or more embodiments;

Figure 2 shows a schematic overview of an extracting unit 140 of the system as depicted in Figure 1 ;

Figure 3 shows a vehicle with a system for functional safety validating an output of an audio message according to one or more embodiments; and.

Figure 4 shows a schematic overview of a method for functional safety validating an output of an audio message in an interior of a vehicle according to one or more embodiments.

DETAILED DESCRIPTION

Figure 1 shows a schematic overview of a system 100 for functional safety validating an output of an audio message in an interior of a vehicle according to one or more embodiments.

The system 100 comprises a signal power modulator 1 10, an audio generator 120, an audio recorder 130, an extracting unit 140 and a validation unit 150.

The signal power modulator 110 is receives an audio message X having an audio spectrum of at least one or more audio frequencies with an amplitude greater than a minimum value and with any phase and modulates the audio message using said audio frequency spectrum as carrier frequencies and predetermined modulation data M for said audio message X. In one or more embodiment, all frequencies of the audio message above the highest frequency of the predetermined modulation data are used for the demodulation.

This can be shown using the following mathematical theorems:

1 . cos(x)*cos(y) = 0,5 * ( cos(x-y) + cos(x+y) )

2. cos²(x) = 0,5 * (1 +cos(2*x))

3. cos(x) = cos(-x)

The following frequencies are defined:

Qi = one of the audio frequencies of said audio spectrum. Qmin is the lowest frequency and Qmax the highest frequency of said audio spectrum. The following equations are valid for any i. co = a frequency for data modulation, e.g. there’s coO = 40 Hz symbolizes a “0” and col = 80 Hz symbolizes a “1”. The highest / lowest used frequency may be noted as comax I comin respectively.

Since audio frequencies of said audio spectrum may be defined by the audio message, the frequencies for data modulation should be chosen such that the ranges of those do not overlap. An example may be: Qi > Qmin > 100 Hz and co < comax < 100 Hz.

In the below, an example of the modulation and the demodulation according to one or more embodiments of the invention, is mathematically demonstrated:

1 . Generating the modulated audio message Xm using the predetermined modulation signal Ms for the audio message X;

X = Sum of all Xi with Xi = Ai * cos( Qi * t), wherein Ai may be different for different i and different phases of Xi are not taken into account as they will not change the result in frequencies.

Ms = cos(co * t), for example either with coO (e.g.= 40 Hz) and col (e.g. = 80 Hz) by which modulation data “0” and “1” is defined.

Xm = X * (1 + r * Ms) with r = modulation factor

For each Xi, the following equation is valid:

Xmi = Ai * cos( Qi * t) * ( 1 + r * cos(co * t) ) = Ai * cos( Qi * t) + 0,5 * Ai * r * ( cos( (Qi + co) t ) + cos ( (Qi - co) t) )

In the extraction unit, the following may take place:

2. Demodulation of XXm with X for all Xi

In a first step, the signal XXm is computed by: XXm = X*Xm. Then the resulting signal XXm is filtered for coO (e.g.= 40 Hz) and for col (e.g. = 80 Hz).

If the signal power of XXm is above a predetermined threshold and the filtered signal for coO is larger than col , a “0” is generated (else an “1”) as estimated modulation data Me

It can be shown that XXm contains the modulations signal M = cos(co * t) either with co = coO (e.g.= 40 Hz) and co = col (e.g. = 80 Hz) for each Xmi. It is assumed that the extraction unit is able to reconstruct the modulated audio message Xm perfectly from the vehicle signal Ym.

The audio power of X and Xmi is computed as follows:

XXmi = Xi * Xmi

= Ai * cos(Qi * t) * (Ai * cos(Qi * t)+0, 5 * Ai * r * ( cos((Qi + co) t ) + cos( (Qi - co) t ) )

= 0,5 * (Ai)² * ( 1 + cos(2 * Qi * t) ) + 0,5* (Ai)² * r * cos(Qi * t) * ( cos((Qi + co) t ) + cos( (Qi - co) t ) )

= 0,5 * (Ai)² * ( 1 + cos(2 * Qi * t) ) + 0,5* (Ai)² * r * 0,5 * ( cos((Qi + (Qi + co)) * t) + cos((Qi - (Qi + co)) * t) + cos((Qi + (Qi - co)) * t) + cos((Qi - (Qi - co)) * t) )

= 0,5 * (Ai)² * ( 1 + cos(2 * Qi * t) ) + 0,25* (Ai)² * r * ( cos((2*Qi + co) * t) + cos(- co * t) + cos((2*Qi - co)) * t) + cos( co * t) )

= 0,5 * (Ai)² * ( 1 + cos( 2 * Qi * t) ) + 0,25 * (Ai)² * r * cos((2*Qi + co) * t) + 0,25 * (Ai)² * r * cos((2*Qi - co) * t) ) + 0,5*(Ai)² * r * cos( co * t) )

Discussion of the result:

The term: 0,5 * (Ai)² * ( 1 + cos( 2 * Qi * t) ) has a constant component and an alternating component with the 2 times of the audio signal frequency. Both can be filtered out easily since its frequency is =0 and > Qmin. This term does not carry modulation data.

The term: 0,25 * (Ai)² * r * cos((2*Qi + co) * t) is a mix of audio message frequencies and modulation data signal. It can be filtered out easily because its frequency is 2*Qi + co > Qmin. The term: 0,25 * (Ai)² * r * cos((2*Qi - co) * t) ) is also a mix of audio message frequencies and modulation data signal. It can be filtered out because its frequency 2*Qi - co > 2* Qmin - comax > Qmin.

The term: 0,5*(Ai)² * r * cos( co * t) ) is the interesting result, which is just carrying the frequency of the modulation data signal. It can be filtered with a low-pass with cut off frequency < Qmin. It then can be further investigated.

In one or more embodiments, the predetermined modulation data M correspond to a predetermined modulation frequency. In one or more embodiments, the predetermined modulation data M comprise periodical and non-periodical modulation data corresponding to a periodical and a non-periodical modulation of said audio message X. The predetermined modulation data M may further comprise pause data corresponding to modulation pauses.

A modulation pause is an absence of modulation in a predetermined time-period, wherein preferably a sound power of said audio message X is below a predefined threshold.

Since the human ear and brain is limited in the processing of sounds, the predetermined modulation data should be chosen such, that the passengers will not be aware or be disturbed of the fact that the audio message has been modulated using predetermined modulation data.

The signal power modulator 110 outputs a modulated audio message Xm to the audio generator 120, the audio message X to the extracting unit 140. The signal power modulator 110 furthermore outputs predetermined modulation data M to the validation unit 150.

In one or more embodiments, the signal power modulator 110 determines a minimum sound power for modulated audio message Xm during a predetermined power period and outputting minimum sound power data Px, corresponding to said minimum sound power, to the validation unit 150.

The audio generator 120 receives the modulated audio message Xm and outputs a speaker sound corresponding to the modulated audio message Xm using one or more speakers 301 in the interior of the vehicle. The audio generator 120 may be arranged for converting modulated audio message Xm into an analogue electrical signal Xn for the one or more speakers 301 . In one or more embodiments, the one or more speakers may be comprised in the audio generator.

The audio recorder 130 receives a vehicle sound using one or more microphones 303 in the interior of the vehicle. The speaker sound may be received directly from the one or more speakers 301 and/or via reflections of the sound by surfaces 302 of the interior. Furthermore, in addition to the speaker sound, the audio recorder 130 may also record environmental noises N generated outside and/or outside the vehicle.

The audio recorder 130 may receive an analogue electrical signal Yn from the one or more microphones 303. The audio recorder 130 outputs a vehicle signal Ym corresponding to the received vehicle sound to the extraction unit 140.

Figure 2 shows a schematic overview of an extracting unit 140 of the system as depicted in Figure 1. In one or more embodiments, the extracting unit 140 may comprises a room acoustics compensator 210 and/or a demodulator 220.

The room acoustics compensator 210 may be storing an inverse audio transfer function (InvGxy) for the interior of the vehicle. The audio transfer function Gxy may be determined from the relation between the cross-power density Sxy of X and Ym to car power density Sxx of X. The impulse response of the room or interior may then be calculated by converting Gx into the time domain, which indicates the sound reflection or echoes of the room. To compensate these reflections, the audio transfer function Gxy is inverted to obtain the inverse audio transfer function (InvGxy = 1/Gxy). But also other ways of determining the inverse audio transfer function InvGxy as known in the art, may be used.

The inverse audio transfer function (InvGxy) may then be used as a filter to extract from vehicle signal Ym the estimated audio signal Xs. The room acoustics compensator 210 may then output the estimated audio signal Xs to the demodulator 220.

The demodulator 220 may demodulate and filter the estimated audio signal Xs using said audio message X and a band filter, in order to obtain an estimated demodulated audio signal XXs. The band filter may be arranged for passing a frequency range which comprises modulation frequencies used for the modulation. The extracting unit 140 may further be arranged for extracting estimated modulation data Me from said estimated demodulated audio signal XXs.

In one or more embodiments, the extracting unit 140 may further comprise a modulation synchronization unit 230 and a modulation data estimation unit 240.

The modulation synchronization unit 230 is arranged for determining an estimated periodic modulation Mb in the estimated demodulated audio signal XXs. The modulation synchronization unit 230 may be further arranged for determining an estimated modulation pauses Mp in the estimated demodulated audio signal XXs. Furthermore, the modulation synchronization unit 230 may be arranged for outputting the estimated periodic modulation Mb and optionally the estimated modulation pauses Mp to the modulation data estimation unit 240.

The modulation data estimation unit 240 uses the estimated demodulated audio signal XXs to determine estimated modulation data Me. For this, the modulation data estimation unit 240 may be further arranged to use the estimated periodic modulation Mb and/or the estimated modulation pauses Mp.

In one or more embodiments, the extracting unit 140, or more specifically the modulation data estimation unit 240, is further arranged for extracting an estimated sound power of the vehicle sound during the predetermined power period using the vehicle signal Ym, or the estimated demodulated audio signal XXs, respectively.

The extracting unit 140 outputs the estimated modulation data Me and optionally the estimated sound power data Pm, corresponding to the estimated sound power, to the validation unit 150.

As can be seen in Figure 1 , the validation unit 150 receives the estimated modulation data Me and said predetermined modulation data M. The validation unit 150 determines a difference between said estimated modulation data Me and said predetermined modulation data M and validates the output of audio message when said difference is below a predetermined threshold. The validation unit 150 outputs validation data corresponding to said validation.

In one or more embodiments, after the output of the audio message has not been validated, the system 100 may - on the basis of the validation data - start the validating an output of an audio message again, in which the audio message is outputted again.

In one or more embodiments, the system 100 further comprises a display 160. The display 160 may be arranged for displaying a visual message to the passengers of the vehicle on the basis of the validation data. The visual message may indicate the content of the audio message in a visual way, preferably using symbols and/or letters, when the output of the audio message has not been validated.

Figure 3 shows a vehicle 310 with a system 100 for functional safety validating an output of an audio message according to one or more embodiments as described in this document. The vehicle 310 may further comprise one or more speakers 303 arranged in the interior of vehicle 310 and/or one or more microphone 301 arranged in the interior of vehicle 310. In one or more embodiments, the vehicle 310 may be a car, a motorbike, a van, a truck, a bicycle, or a scooter. In one or more embodiments, the system 100 may be part of the infotainment system of vehicle 310.

Figure 4 shows a schematic overview of a method 400 for functional safety validating an output of an audio message in an interior of a vehicle according to one or more embodiments.

The method 400 comprises the steps of:

[410] receiving an audio message X having an audio spectrum of at least one or more audio frequencies with an amplitude Ai greater than a minimum value and with any phase;

[420] modulating said audio message X using said audio spectrum as carrier frequencies and predetermined modulation data for said audio message;

[430] outputting a speaker sound corresponding to said modulated audio message Xm using one or more speakers in said interior of said vehicle 310;

[440] receiving a vehicle sound using one or more microphones in said interior of said vehicle 310;

[450] generating a vehicle signal Ym corresponding to said received vehicle sound; [460] extracting estimated modulation data Me from said vehicle signal Ym using said audio message X;

[470] determining a difference between said estimated modulation data and said predetermined modulation data; [480] validating an output of said audio message when said difference is below a predetermined threshold; and,

[490] generating validation data corresponding to said validation.

In one or more embodiments, said predetermined modulation data M correspond to a predetermined modulation frequency; and/or wherein said predetermined modulation data M comprise: a. periodical modulation data corresponding to a periodical modulation of said audio message X; and, b. non-periodical modulation data corresponding to a non-periodical modulation of said audio message X; and, preferably, c. pause data corresponding to modulation pauses, wherein a modulation pause is an absence of modulation in a predetermined time-period, wherein preferably a sound power of said audio message X is below a predefined threshold.

In one or more embodiments, the further comprises the steps of:

[510] determining a minimum sound power Px for modulated audio message Xm during a predetermined power period;

[520] generating minimum sound power data, corresponding to said minimum sound power Px, to said validation unit;

[530] extracting an estimated sound power Pm of said vehicle sound during said predetermined power period using said vehicle signal Ym;

[540] generating estimated sound power data, corresponding to said estimated sound power Pm, to said validation unit,

[550] validating the output of said audio message when said estimated sound power Pm is equal to or higher than said minimum sound power Px.

In one or more embodiments, the further comprises the steps of:

[610] determining an estimated audio signal Xs based on the vehicle signal Ym and said audio message X using the inverse audio transfer function InvGxy;

[620] demodulating said estimated audio signal using said audio message, and optionally for filtering the demodulation results using a band filter, in order to obtain an estimated demodulated audio signal, wherein said optional band filter passes a frequency range which comprises modulation frequencies used for said modulation; and, [630] extracting estimated modulation data Me from said estimated demodulated audio signal XXs.

In one or more embodiments, the further comprises the steps of:

[710] Method according to claim 11 , further comprising the step of: extracting estimated periodical modulation data Mb from said estimated demodulated audio signal XXs, wherein said estimated modulation data Me is extracted using said estimated periodical modulation data Mb; and/or

[720] extracting estimated pause data Mp from said estimated demodulated audio signal XXs, wherein said estimated modulation Me comprises said estimated pause data Mp

Those of skill will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those of skill in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The benefits and advantages that may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the claims. As used herein, the terms “comprises,” “comprising,” or any other variations thereof, are intended to be interpreted as non-exclusively including the elements or limitations which follow those terms.

Accordingly, a system, method, or other embodiment that comprises a set of elements is not limited to only those elements and may include other elements not expressly listed or inherent to the claimed embodiment.

While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention as detailed within the following claims.

Claims

1 . System for functional safety validating an output of an audio message in an interior of a vehicle, the system comprising:

- a signal power modulator

- audio generator

- audio recorder

- extracting unit

- validation unit wherein the signal power modulator is arranged for:

- receiving an audio message (X) having an audio spectrum of at least one or more audio frequencies with an amplitude greater than a minimum value and with any phase;

- modulating said audio message using said audio frequency spectrum as carrier frequencies and predetermined modulation data (M) for said audio message (X);

- outputting a modulated audio message (Xm) to said audio generator, outputting said audio message to said extracting unit and outputting said predetermined modulation data (M) to said validation unit; wherein the audio generator is arranged for:

- receiving said modulated audio message (Xm);

- outputting a speaker sound corresponding to said modulated audio message (Xm) using one or more speakers in said interior of said vehicle; wherein the audio recorder is arranged for

- receiving a vehicle sound using one or more microphones in said interior of said vehicle;

- outputting a vehicle signal (Ym) corresponding to said received vehicle sound to said extraction unit; wherein the extracting unit is arranged for:

- receiving said vehicle signal (Ym) and said audio message (X);

- extracting estimated modulation data (Me) from said vehicle signal (Ym) using said audio message (X);

- outputting said estimated modulation data (Me) to said validation unit, wherein said validation unit is arranged for:

- receiving said estimated modulation data (Me) and said predetermined modulation data (M);

- determining a difference between said estimated modulation data (Me) and said predetermined modulation data (M);

- validating an output of said audio message when said difference is below a predetermined threshold;

- outputting validation data corresponding to said validation.

2. System according to claim 1 ,

- wherein said predetermined modulation data (M) correspond to a predetermined modulation frequency; and/or

- wherein said predetermined modulation data (M) comprise o periodical modulation data corresponding to a periodical modulation of said audio message (X); and, o non-periodical modulation data corresponding to a non-periodical modulation of said audio message (X); and, preferably, o pause data corresponding to modulation pauses, wherein a modulation pause is an absence of modulation in a predetermined time-period, wherein preferably a sound power of said audio message (X) is below a predefined threshold.

3. System according to any of the preceding claims, wherein said signal power modulator is further arranged for

- determining a minimum sound power for modulated audio message (Xm) during a predetermined power period;

- outputting minimum sound power data (Px), corresponding to said minimum sound power, to said validation unit; wherein said extracting unit is further arranged for:

- extracting an estimated sound power (Pm) of said vehicle sound during said predetermined power period using said vehicle signal (Ym);

- outputting estimated sound power data, corresponding to said estimated sound power (Pm), to said validation unit, wherein said validation unit is further arranged for:

- receiving said estimated sound power data and said minimum sound power data;

- validating the output of said audio message when said estimated sound power (Pm) is equal to or higher than said minimum sound power (Px).

4. System according to any of the previous claims, wherein the extracting unit is further arranged for:

- storing an inverse audio transfer function (InvGxy) for said interior;

- determining an estimated audio signal (Xs) based on the vehicle signal (Ym) and said audio message (X) using the inverse audio transfer function (InvGxy);

- demodulating said estimated audio signal using said audio message, and optionally for filtering the demodulation results using a band filter, in order to obtain an estimated demodulated audio signal, wherein said optional band filter passes a frequency range which comprises modulation frequencies used for said modulation; and,

- extracting estimated modulation data (Me) from said estimated demodulated audio signal (XXs)

5. System according to claim 4 depending on claim 2, wherein the extracting unit is further arranged for:

- extracting estimated periodical modulation data (Mb) from said estimated demodulated audio signal (XXs); wherein said estimated modulation data (Me) is extracted using said estimated periodical modulation data (Mb).

6. System according to any of claims 4-5 depending on claim 2, wherein the extracting unit is further arranged for:

- extracting estimated pause data (Mp) from said estimated demodulated audio signal (XXs); wherein said estimated modulation data (Me) is extracted using said estimated pause data (Mp)

7. Vehicle comprising a system for functional safety validating an output of an audio message according to any of claim 1 -6.

8. Method for functional safety validating an output of an audio message in an interior of a vehicle, the method comprising the steps of:

- outputting a speaker sound corresponding to said modulated audio message (Xm) using one or more speakers in said interior of said vehicle;

- generating a vehicle signal (Ym) corresponding to said received vehicle sound;

- generating validation data corresponding to said validation.

9. Method according to claim 8, wherein said predetermined modulation data (M) correspond to a predetermined modulation frequency; and/or wherein said predetermined modulation data (M) comprise: a. periodical modulation data corresponding to a periodical modulation of said audio message (X); and, b. non-periodical modulation data corresponding to a non-periodical modulation of said audio message (X); and, preferably, c. pause data corresponding to modulation pauses, wherein a modulation pause is an absence of modulation in a predetermined time-period, wherein preferably a sound power of said audio message (X) is below a predefined threshold.

10. Method according to any of claims 8-9, further comprising the steps of:

- determining a minimum sound power (Px) for modulated audio message (Xm) during a predetermined power period;

- generating minimum sound power data, corresponding to said minimum sound power (Px), to said validation unit;

- generating estimated sound power data, corresponding to said estimated sound power (Pm), to said validation unit,

11 . Method according to any of claims 8-10, further comprising the steps of:

- extracting estimated modulation data (Me) from said estimated demodulated audio signal (XXs).

12. Method according to claim 11 , further comprising the step of: extracting estimated periodical modulation data (Mb) from said estimated demodulated audio signal (XXs), wherein said estimated modulation data (Me) is extracted using said estimated periodical modulation data (Mb).

13. Method according to claim 11 , further comprising the step of: extracting estimated pause data (Mp) from said estimated demodulated audio signal (XXs), wherein said estimated modulation (Me) comprises said estimated pause data (Mp)

14. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method of any of claims 1 -7.

15. A computer-readable medium having stored thereon the computer program of claim 14.