Method for inspecting the emission of an audio safety message in a vehicle

Abstract

A method for monitoring the transmission of a safety audio message to the occupants of the passenger compartment of a vehicle. The method including transmitting an audio signal comprising the safety audio message and, mixed with said safety audio message, an identification signal including an identification digital audio message that is looped and frequency modulated, recording the ambient sound in the passenger compartment using a microphone, filtering and demodulating the signal to reconstruct the identification signal, analyzing the reconstructed identification signal to determine: whether the unique identifier corresponding to the transmitted safety audio message is found therein, and whether the time for which the identification signal was transmitted without interruption is indeed equal to the known duration of the safety audio signal, determining that the safety audio message has or has not been correctly transmitted in its entirety depending on the analyzing step.

Claims

1. A method for monitoring the transmission of a safety audio message via at least one loudspeaker located onboard a vehicle to the occupants of the passenger compartment of said vehicle, said safety audio message having a predetermined duration, said loudspeaker having a maximum frequency, said method comprising: transmitting an audio signal comprising the safety audio message and, mixed with said safety audio message, an identification signal comprising an identification digital audio message that is looped and frequency modulated, said identification signal having a frequency comprised between 20 kHz and a frequency ceiling lower than a maximum frequency of said loudspeaker, the identification digital audio message comprising a unique identifier associated with said safety audio message, recording an ambient sound in the passenger compartment by a microphone, filtering the recorded signal by a bandpass filter, so as to obtain a filtered signal having frequencies comprised between 20 kHz and a frequency ceiling, demodulating the filtered signal so as to reconstruct the identification signal comprising the looped identification digital audio message, analyzing the reconstructed identification signal to determine: whether the unique identifier corresponding to the transmitted safety audio message is found therein, and by counting a number of occurrences of the identification digital audio message in said reconstructed identification signal, whether the time for which the identification signal was transmitted without interruption is indeed equal to the predetermined duration of the safety audio signal, and determining that the safety audio message has or has not been correctly transmitted in the safety audio message's entirety depending on the analyzing step.

2. The method as claimed in claim 1, wherein, if at the end of the determining step it is determined that the safety audio message has not been transmitted or not been transmitted in its entirety, then a step of retransmitting the audio signal comprising the safety audio message and the identification signal is executed.

3. The method as claimed in claim 1, wherein, if at the end of the determining step it is determined that the safety audio message has not been transmitted or not been transmitted in its entirety, then a step of displaying an information message on a display screen of the vehicle is executed.

4. The method as claimed in claim 1, wherein the filtering obtained by the bandpass filter in the filtering step is carried out so as to select a frequency band comprised between 20 kHz and 22 kHz.

5. A system configured to be located onboard a vehicle comprising: a loudspeaker, a microphone configured to record the ambient sound in the passenger compartment of the vehicle; and a processor configured to implement the method as claimed in claim 1.

6. A motor vehicle comprising a system as claimed in claim 5.

7. The method as claimed in claim 2, wherein, if at the end of the determining step it is determined that the safety audio message has not been transmitted or not been transmitted in its entirety, then a step of displaying an information message on a display screen of the vehicle is executed.

8. The method as claimed in claim 2, wherein the filtering obtained by the bandpass filter in the filtering step is carried out so as to select a frequency band comprised between 20 kHz and 22 kHz.

9. The method as claimed in claim 3, wherein the filtering obtained by the bandpass filter in the filtering step is carried out so as to select a frequency band comprised between 20 kHz and 22 kHz.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of aspects of the invention will become apparent from the following description, which is given with reference to the appended figures, which are provided by way of non-limiting example and in which objects that are similar have been referenced with identical reference signs.

(2) FIG. 1 shows the schematic of a vehicle equipped with a system capable of implementing an aspect of the invention,

(3) FIG. 2 shows a block diagram showing the steps of the method according to an aspect of the invention,

(4) FIG. 3 shows the principle of an identification digital signal mixed with a safety audio message.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) An aspect of the invention is envisioned mainly for implementation in a motor vehicle. However, other applications, in particular the implementation of the system and method according to an aspect of the invention in any other type of means for transporting passengers, is also targeted.

(6) FIG. 1 shows, by way of non-limiting illustration, a vehicle 10 in which an aspect of the present invention may be implemented. The vehicle 10 comprises an IVI system (IVI being the acronym of In-Vehicle Infotainment). This system comprises a processor 1, at least one loudspeaker 2 and at least one recording microphone 3.

(7) The processor 1 is configured to transmit safety audio messages via the loudspeakers 2 to occupants of the passenger compartment 4.

(8) FIG. 2 shows a functional block diagram allowing the method according an aspect of to the invention to be described.

(9) Thus, in a vehicle for transporting passengers, such as a motor vehicle, in which a processor 1 generates and transmits a safety audio message intended to be heard by occupants of the passenger compartment 4, provision is made for a step E1 of transmitting an identification digital audio message mixed with the safety audio message starting at a transmission time requested by said processor 1.

(10) In other words, the processor 1 requests the transmission E1 of an audio signal comprising the safety audio message and, mixed with said safety audio message, an identification signal.

(11) With reference to FIG. 3, the identification digital audio message 21 is thus frequency modulated to form the identification signal 20, the latter having inaudible frequencies that are higher than 20 kHz and lower than the maximum frequency that the one or more loudspeakers 2 are able to transmit.

(12) In particular, the frequencies of the identification signal 20 are comprised between 20 kHz and 22 kHz, the maximum frequency that the one or more loudspeakers 2 are able to transmit being higher than 22 kHz.

(13) The safety audio message 30 has a known duration, and the identification digital audio message 21 is mixed looped to form an identification signal 20, which is transmitted from the transmission time, which corresponds to the start of transmission of the safety audio message 30, and for a time equal to the known duration of the safety audio message 30.

(14) With reference once again to FIG. 2, the method according to an aspect of the invention comprises recording E2 the ambient sound in the passenger compartment 4, and in particular the sound transmitted as output from the one or more loudspeakers 2.

(15) The filtering E3 of the recorded signal comprises bandpass filtering that allows all audible frequencies to be removed from the signal, in order to eliminate any parasitic ambient noise therefrom.

(16) In particular, the bandpass filter applied in step E3 produces a filtered signal solely containing frequencies comprised between 20 kHz and 22 kHz, the frequencies of the identification signal containing the identification digital audio signal being comprised between these limits.

(17) The processing E4 of the filtered signal comprises demodulating said filtered signal so as to reconstruct the identification signal comprising the looped identification digital audio message.

(18) Analysis E5 of the reconstructed identification signal makes it possible to determine whether the unique identifier corresponding to the transmitted safety audio message is found therein, and, by counting the number of occurrences of the identification digital audio signal, it is determined whether the time for which the identification signal was transmitted without interruption is indeed equal to the known duration of the safety audio signal.

(19) At the end of the analyzing step E5, the determining step E6 makes it possible to determine whether transmission of the entire length of the safety audio message could be confirmed or not.

(20) In case of non-confirmation of correct transmission of the safety audio signal, provision may be made to retransmit said safety audio message and/or to display an information message on a display screen.

(21) It is clarified furthermore that aspects of the present invention are not limited to the examples described above, and is open to many variants that are accessible to those skilled in the art.