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EP-4738342-A1 - ACOUSTIC NOISE SUPPRESSION SYSTEM, COMPUTER-IMPLEMENTED METHOD THEREFOR, COMPUTER PROGRAM AND NON-VOLATILE DATA CARRIER

EP4738342A1EP 4738342 A1EP4738342 A1EP 4738342A1EP-4738342-A1

Abstract

A transmitter unit (100) acquires a source signal (ss) representing an acoustic source signal (s A ) emitted from a noise pollution source (S) and based thereon transmits a wireless signal (R[s FF ]) containing a feedforward signal (s FF ). A receiver unit (200) arranged at a target position (T) receives the wireless signal (R[s FF ]), and based thereon feeds a cancelling signal (sc) towards a target position (T), which cancelling signal (sc) suppresses the acoustic source signal (s A ) after having propagated from the noise pollution source (S) to the target position (T). A first signal processing unit (120) in the transmitter unit (100) associates time-stamp data (t 1 ) with the feedforward signal (s FF ), which time-stamp data (t 1 ) link the source signal (ss) to a time frame (t) that is common between the first and second signal processing units (120; 220) and includes the time-stamp data (t 1 ) in the wireless signal (R[s FF ]). A second signal processing unit (220) in the receiver unit (200) produces the cancelling signal (sc) on the further basis of the time-stamp data (t 1 ) so that the anti-noise signal (ac) is estimated to reach the target position (T) with a timing that matches a propagation time (T P ) required for the acoustic source signal (s A ) to travel from the noise pollution source (S) to the target position (T).

Inventors

  • WAHLBERG, PER

Assignees

  • Etheron AB

Dates

Publication Date
20260506
Application Date
20241030

Claims (18)

  1. An acoustic noise suppression system, comprising: a transmitter unit (100) adapted to be arranged at a noise pollution source (S), which transmitter unit (100) comprises: a first microphone (110) configured to acquire a source signal (ss) that represents an acoustic source signal (s A ) emitted from the noise pollution source (S), a first signal processing unit (120) configured to produce a feedforward signal (s FF ) based on the source signal (ss), which feedforward signal (s FF ) describes an audible stream of soundwaves comprised in the acoustic source signal (sa), a first wireless interface (130) configured to transmit a wireless signal (R[s FF ]) comprising the feedforward signal (SFF), a receiver unit (200) adapted to be arranged at a target position (T), which receiver unit (200) comprises: a second wireless interface (230) configured to receive the wireless signal (R[s FF ]), a second signal processing unit (220) configured to produce a cancelling signal (sc) based on the wireless signal (R[s FF ]), which cancelling signal (sc) is adapted to form a basis for an anti-noise signal (ac) suppressing the acoustic source signal (s A ) after having propagated through a fluid from the noise pollution source (S) to the target position (T), and an audio sound transducer (210) configured to generate the anti-noise signal (ac) based on the cancelling signal (sc), which anti-noise signal (ac) is fed towards the target position (T), characterized in that the first signal processing unit (120) is further configured to associate time-stamp data (t 1 ) with the feedforward signal (s FF ), which time-stamp data (t 1 ) link the source signal (ss) to a time frame (t) being common between the first and second signal processing units (120; 220), and which time-stamp data (t 1 ) are comprised in the wireless signal (R[s FF ]), and the second signal processing unit (220) is configured to produce the cancelling signal (sc) on the further basis of the time-stamp data (t 1 ) so that the anti-noise signal (ac) is estimated to reach the target position (T) with a timing that matches a propagation time (T P ) required for the acoustic source signal (s A ) to travel through the fluid from the noise pollution source (S) to the target position (T).
  2. The system according to claim 1, wherein the second signal processing unit (220) is configured to produce the cancelling signal (sc) so that the anti-noise signal (ac) comprises a stream of soundwaves with such amplitude variations that the anti-noise signal (ac) is estimated to cancel out the audible stream of soundwaves comprised in the acoustic source signal (s A ) at the target position (T).
  3. The system according to claim 2, wherein: the receiver unit (200) is communicatively connected to a second microphone (215) configured to acquire a target signal (s T ) that represents the acoustic source signal (s A ) after having propagated through the fluid from the noise pollution source (S) to the target position (T), the receiver unit (200) further comprises a digital memory (240) configured to store a representation of the target signal (s T ), and the second signal processing unit (220) is further configured to: derive a reference signal (s AR ) from the wireless signal (R[s FF ]), correlate the stored representation of the target signal (s T ) with the reference signal (s AR ) to based thereon and with reference to said common time frame (t), determine the propagation time (T P ).
  4. The system according to claim 3, wherein each of the reference signal (s AR ) and the target signal (s T ) comprises a respective series of sample values, and the second signal processing unit (220) is configured to correlate the stored representation of the target signal (s T ) with the reference signal (s AR ) by: comparing a first set of consecutive sample values from the series of sample values in the reference signal (s AR ) in a first temporal window (W1) with a second set of consecutive sample values from the series of sample values in the target signal (s T ) in a second temporal window (W2), which first temporal window (W1) covers an extension in time that is equal to an extension in time covered by the second temporal window (W2), and determining the propagation time (T P ) as a time shift between the first and second temporal windows (W1; W2) with respect to said common time frame (t) at which time shift the first and second sets of consecutive sample values fulfil a similarity criterion.
  5. The system according to any of claims 3 or 4, wherein the second signal processing unit (220) is configured to determine the propagation time (T P ) during a setup procedure for the system.
  6. The system according to any one of claims 3 to 5, wherein the second signal processing unit (220) is configured to repeat the determining of the propagation time (T P ) at repeated occasions during operation of the system.
  7. The system according to any one of the preceding claims, wherein: the transmitter unit (100) comprises a first clock generator (145) configured to generate a first basis for the time frame (t) in relation to which first basis the first signal processing unit (120) is configured to associate time-stamp data (t 1 ) to the feedforward signal (s FF ), the receiver unit (200) comprises a second clock generator (245) configured to generate a second basis for the time frame (t) in relation to which second basis the second signal processing unit (220) is configured to produce the cancelling signal (sc), and the first and second clock generators (145; 245) are synchronized to one another.
  8. The system according to claim 7, wherein each of the first and second clock generators (145; 245) is communicatively connected to a clock source (150) that provides a common clock signal (CLK) to the first and second clock generators (145; 245), wherein the first clock generator (145) is configured to generate the first basis for the time frame (t) based on the common clock signal (CLK) and the second clock generator (245) is configured to generate the second basis for the time frame (t) based on the common clock signal (CLK).
  9. The system according to any one of the preceding claims, wherein the transmitter unit (100) is adapted to be arranged at the noise pollution source (S) in the form of a potential snorer and the receiver unit (200) is adapted to be arranged at the target position (T) in the form of a user wishing to avoid being disturbed by the potential snorer.
  10. The system according to any one of the preceding claims, wherein the first microphone (110) is disposed on at least one of: a chinstrap (310), a headband (410) and an adhesive tape (510) adapted to be worn by a subject (300).
  11. The system according to any one of claims 9 or 10, further comprising a server (830) communicatively connected to a network (830), which server (830) is further communicatively connected to a database (835), wherein the transmitter unit (100) comprises a first network interface (810) configured to be communicatively connected to the network (800) and the receiver unit (200) comprises a second network interface (820) configured to be communicatively connected to the network (800), wherein the first signal processing unit (120) is configured to: process the source signal (ss) to derive acoustic source data (D AS ) that characterize the source signal (ss) in terms of at least one of: occurrence, duration, repetitive pattern behavior, waveforms and frequency spectra, and cause the first network interface (810) to send the acoustic source data (D AS ) via the network (800) to the server (830), wherein the server (830) is configured to: store the acoustic source data (D AS ) in the database (835), analyze the acoustic source data (D AS ) that have been stored in the database (835) over a period to derive at least one typical feature of the source signal (ss), and based on the at least one typical feature generate at least one supporting parameter (Ps), and send the at least one supporting parameter (Ps) via the network (800) to the receiver unit (200), and wherein the receiver unit (200) is configured to: obtain the at least one supporting parameter (Ps) through the second network interface (820), and produce the cancelling signal (sc) on the further basis of the at least one supporting parameter (Ps).
  12. The system according to any one of the preceding claims, wherein the receiver unit (200) is comprised in an earphone unit (610) adapted to be worn by a subject.
  13. The system according to any one of the preceding claims, wherein the first signal processing unit (120) is configured to: monitor a signal strength of the source signal (ss) acquired via the first microphone (110), and if the signal strength subceeds a first threshold level, control the first wireless interface (130) to a standby mode in which the first wireless interface (130) does not transmit the wireless signal (R[s FF ]), and if, during a period when the first wireless interface (130) is in the standby mode, the signal strength exceeds a second threshold level above the first threshold level, control the first wireless interface (130) to an active mode in which the first wireless interface (130) transmits the wireless signal (R[s FF ]).
  14. The system according to any one of the preceding claims, wherein the second signal processing unit (220) is configured to: monitor the second wireless interface (230), and if the wireless signal (R[s FF ]) is not received via the second wireless interface (230), control the audio sound transducer (210) to generate the anti-noise signal (ac) such that the anti-noise signal (ac) comprises a stream of a default masking soundwaves.
  15. The system according to any one of the preceding claims, wherein the first and wireless interfaces (130, 230) are configured to communicate data according to at least one of the standards BLE, Bluetooth, ANT, UWB, Zigbee and Wireless USB.
  16. A computer-implemented method for acoustic noise suppression, which method comprises: acquiring, via a first microphone (110), a source signal (ss) that represents an acoustic source signal (s A ) emitted from a noise pollution source (S); producing, in a first signal processing unit (120), a feedforward signal (s FF ), which feedforward signal (s FF ) is based on the source signal (ss) and describes an audible stream of soundwaves comprised in the acoustic source signal (sa); transmitting, via a first wireless interface (130), a wireless signal (R[s FF ]) that comprises the feedforward signal (s FF ); receiving, via a second wireless interface (230), the wireless signal (R[s FF ]); producing, in a second signal processing unit (220), a cancelling signal (sc), which cancelling signal (sc) is based on the wireless signal (R[s FF ]) and is adapted to form a basis for an anti-noise signal (ac) suppressing the acoustic source signal (s A ) after having propagated through a fluid from the noise pollution source (S) to the target position (T); and generating, via an audio sound transducer (210), the anti-noise signal (ac), which anti-noise signal (ac) is based on the cancelling signal (sc) and is fed towards the target position (T), characterized by the method further comprising: associating, in the first signal processing unit (120), time-stamp data (t 1 ) with the feedforward signal (s FF ), which time-stamp data (t 1 ) link the source signal (ss) to a time frame (t) being common between the first and second signal processing units (120; 220); including the time-stamp data (t 1 ) in the wireless signal (R[s FF ]), and producing, in the second signal processing unit (220), the cancelling signal (sc) on the further basis of the time-stamp data (t 1 ) so that the anti-noise signal (ac) is estimated to reach the target position (T) with a timing that matches a propagation time (T P ) required for the acoustic source signal (s A ) to travel through the fluid from the noise pollution source (S) to the target position (T).
  17. A computer program (725) loadable into a non-volatile data carrier (720) communicatively connected to a processor (710), the computer program (725) comprising software for executing the method according to claim 16 when the computer program (725) is run on the processor (710).
  18. A non-volatile data carrier (720) containing the computer program (725) of claim 17.

Description

TECHNICAL FIELD The present invention relates generally to suppression of undesired sounds. Especially, the invention relates to a system according to the preamble of claim 1 and a corresponding computer-implemented method. The invention also relates to a computer program for executing the method, and a non-volatile data carrier storing such a computer program. BACKGROUND Good sleep quality is fundamental for the health and well-being of all humans. Disturbing noise is an important reason for poor sleep quality. In our modern life, snoring constitutes one example of such a disturbance. This is especially true for individuals who share sleeping environment with a snorer. US 2014/0276227 describes an apparatus and method that can provide for snore detection and management in the form of either wearable devices or non-wearable devices, or a combination thereof. In some examples, a method includes receiving an acoustic signal, characterizing the acoustic signal as a snoring sound to determine presence of a snoring condition, and transmitting a notification signal to cause notification of the detection of the snoring sound. Optionally, the method can include receiving the notification signal and causing a notification source to notify of the presence of a snoring condition or any other sleep disturbance. For example, the notification source can be configured to impart vibrations unto a source of the snoring sound, responsive to the vibratory activation signal, to indicate the presence of the snoring condition. WO 2016/124252 discloses a method for generating a first sound filter for suppression of snoring induced sounds comprises recording a first sound signal at a first measurement location in proximity of a source of snoring sounds, recording a second sound signal at a second measurement location in proximity of a person to be isolated from snoring sounds, determining a first snoring sound signal from the source by comparing the first sound signal with the second sound signal and setting first adaptive filters based on the first snoring sound signal. The disclosure further relates to systems for generating sound filters, and methods and systems for suppressing snoring induced sounds. US 10,242,657 reveals a kit for attenuation of noise. The kit includes a noise source audio transducer, two earpieces, and a control unit. The two earpieces have respective resilient bodies that engage outer portions of ear canals of respective ears of a user while respective in-ear transducers of the two earpieces are respectively positioned in inner portions of the ear canals. The respective in-ear transducers detect discrepancies (e.g., incomplete superpositio-ning) between the noise and the anti-noise. The respective in-ear transducers optionally detect respective secondary path effects in the ear canals. The noise source audio transducer detects noise generated by a noise source (e.g., snoring noise). The control unit configures an adaptive filter based at least in part on an error signal, and optionally based in part on secondary path effects. The control unit generates signals representative of anti-noise. The two earpieces produce the anti-noise responsive to the signals. The two earpieces produce masking noise with sound level that varies in direct correlation with sound level of the noise generated by the noise source. Thus, various solutions are known for tackling undesired sounds in a sleeping environment. However, none of the known solutions is capable of reducing, for example snoring-related sounds so efficiently that a subject located right next to the noise source can rest assured that he/she will not be disturbed by the emanating noise. SUMMARY The object of the present invention is therefore to offer an improved solution for acoustic noise suppression that addresses the above problem. According to one aspect of the invention, the object is achieved by an acoustic noise suppression system that includes a transmitter unit adapted to be arranged at a noise pollution source, for example near or on a snorer, and a receiver unit adapted to be arranged at a target position, for example in the ear channel of a user. The transmitter unit, in turn, contains a first microphone, a first signal processing unit and a first wireless interface. The first microphone is configured to acquire a source signal that represents an acoustic source signal emitted from the noise pollution source. The first signal processing unit is configured to produce a feedforward signal, e.g. of a digital format based on the source signal. The feedforward signal thus describes an audible stream of soundwaves comprised in the acoustic source signal. The first wireless interface is configured to transmit a wireless signal, e.g. a radio signal that contains the feedforward signal. The receiver unit, in turn, contains a second wireless interface, a second signal processing unit and an audio sound transducer, for instance in the form of a speaker. The seco