• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method and a system for masking and selective cancellation of noise comprising: emitting, by an acoustic emitter, a previously known noise signal; receiving, in a receiver headphones, a signal of ambient noise comprising the signal of emitted noise; extracting at least a first identifying characteristic of the emitted noise signal; in response to the first identification feature, select a first noise canceling signal that corresponds to the noise signal emitted in a push-pull; and providing, in an output of the receiver headphones, the first selected noise cancellation signal, which cancels only the emitted noise signal. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2663650A1
    申请号:ES201830158
    申请日:2018-02-22
    公开日:2018-04-16
    发明作者:Guillermo De Arcas Castro；César ASENSIO RIVERA
    申请人:Universidad Politecnica de Madrid；
    IPC主号:
    专利说明:

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    METHOD AND SYSTEM FOR SELECTIVE MASKING AND CANCELLATION OF
    NOISE
    DESCRIPTION
    OBJECT OF THE INVENTION
    The present invention relates to the technical field of audio processing and more specifically to the methods and systems for the selective cancellation of noise in acoustically degraded environments on purpose.
    BACKGROUND OF THE INVENTION
    Noise, depending on its intensity, is a determining factor for people's situational awareness. The auditory sensation in acoustically degraded environments by certain noises compromises the sensing of an environment to the point that it can reduce the efficiency in the performance of activities. One of the reasons why the sensorization is compromised is due to the masking effect that a high intensity noise entails, since it prevents a human being from perceiving other acoustic signals, which, when masked, are inaudible in practice.
    For example, a pilot uses headphones in the cabin of an airplane to be able to improve, on the one hand, the listening of communications by isolating his ear from the noise that occurs in the cabin itself, and on the other hand, protecting his ear from injury. auditory However, the use of hearing protectors in very noisy environments can cause non-listening of alert sounds, or of dangerous situations in which the loss of situational awareness that implies may be critical, for example in scenarios such as military interventions or police, where the loss of acoustic capacity can cause a delay in the detection of risks and reaction capacity.
    High intensity noises are also used in alarm devices in homes in order to request help in the largest possible radius, but also to stun the intruder of the home with a high intensity noise. On the contrary, the same
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    noise also affects the homeowner, so that the masking effect of alarm noise on other noises can compromise their safety and even lead to involuntary confrontation with the intruder, since it will be impossible for both of them to detect noises as footsteps, doors or voices while high intensity noise is present.
    In the state of the art there are headphones with active noise control, which allows to improve the degree of isolation against the external noise of the headset, favoring the listening of the sounds (communications) produced inside it. These types of headphones are intended to reduce background noise, improving the quality of listening to the earpiece's own emissions. This is the case of the noise canceling headphones disclosed in US 5182774 A, the active noise reduction headphones of US 9445184 B2 or the method and active noise cancellation system applied to headphones proposed in the document EP 3107312 A1. Problems with these types of solutions arise when using the headphones in areas or situations where it would be desirable to perceive other ambient sounds, such as in a combat zone, where preserving or even increasing situational awareness is essential.
    Some other solutions propose a selective filtering of certain noises based on a previous knowledge of what sound you don't want to eliminate. These types of solutions are generally based on voice recognition, such as in US2016063997 A1, to offer a clean speech eliminating ambient noise or to allow listening to certain specific and previously identified sounds, such as a name or A police siren. However, these solutions only allow a very specific type of sounds to pass through that have had to be fully characterized previously, but in situations of high noise pollution they will be unable to discriminate between a masking noise and any ambient noise that has not been characterized.
    Therefore, a solution that performs active noise control exclusively for a type of controlled high masking sound is lacking in the state of the art
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    intensity that acoustically degrades and on purpose an environment in which eventually sounds are produced that are desired to be perceived.
    DESCRIPTION OF THE INVENTION
    In order to achieve the objectives and avoid the aforementioned drawbacks, the present invention describes, in a first aspect, a method for selective noise cancellation comprising the following steps:
    a) emit, by an acoustic emitter, a previously known noise signal;
    b) receive, in a receiving device, an ambient noise signal, where the ambient noise signal comprises the noise signal emitted by the acoustic emitter (where the noise signal emitted by the acoustic emitter masks any other ambient noise);
    c) extracting, at the receiving device, at least a first identifying characteristic of the noise signal emitted by the acoustic emitter;
    d) in response to the first identifying characteristic, select a first noise cancellation signal that corresponds to the masking noise signal emitted in counter phase;
    e) provide, at an output of the receiving device, the first noise cancellation signal selected, which cancels, at least in part, the noise signal emitted by the acoustic emitter, in the ambient noise signal.
    In one of the embodiments of the invention, emitting the noise signal comprises the previous steps of: providing a first database with a catalog of noise signals associated with different characteristics; select a noise signal from those provided to the first database; generate the selected noise signal according to its associated characteristics; and amplify the generated signal.
    Additionally, in one of the embodiments of the invention it is contemplated to adapt the selected noise cancellation signal by means of an adaptive controller
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    feedback from an error microphone arranged in the receiving device. Thus, the cancellation signal emitted can be advantageously adjusted to the real context of the user and minimize the possible error.
    The adaptive controller, according to one of the particular embodiments of the invention comprises: receiving, by the error microphone, a noise signal comprising the ambient noise signal and the first noise cancellation signal generated, where at least one part of the signal emitted by the acoustic emitter has not been totally canceled by said first cancellation signal; extract at least a second identifying characteristic of the noise signal emitted by the acoustic emitter; in response to the second identifying characteristic, select a second noise cancellation signal; and provide to the adaptive controller, the second noise cancellation signal selected, to cancel in the noise signal received by the error microphone the part of the signal emitted by the acoustic emitter not canceled by the first cancellation signal.
    The interaction of the modules can feed back the headphones of the invention and, according to different embodiments of the invention, simply adapt the first noise cancellation signal selected according to the masking noise signal received or, according to a more precise configuration, adapt the first noise cancellation signal based on the signal that the error microphone picks up, which contributes to the improvement of the process by performing an adaptive control that minimizes the error signal.
    Optionally, in an embodiment of the invention where the first cancellation signal provided at the output of the receiving device interferes with the ambient noise signal, it is further contemplated: to receive in the receiving device a noise signal generated as a result of interference from the ambient noise signal and the first cancellation signal; and amplify in the receiving device the noise signal received in the previous step. Advantageously, it is thus possible to improve the situational awareness of the user and to provide the user with the headphones of the present invention, not only the masking of the noises that may occur with their movements or their voice, but also
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    an enhanced listening ability of the environment is also advantageously provided.
    Another aspect of the invention relates to a system for selective noise cancellation comprising:
    - an acoustic emitter configured to emit a previously known noise signal;
    - a receiving device, preferably headphones, configured to receive an ambient noise signal, where the ambient noise signal comprises the noise signal emitted by the acoustic emitter (where the noise signal emitted by the acoustic emitter has characteristics such that masks any other ambient sound); extract at least one identifying characteristic of the noise signal emitted by the acoustic emitter; in response to the identifying characteristic, select a noise cancellation signal that corresponds to the noise signal emitted in contraphase; provide the selected noise cancellation signal at one output, to cancel the noise signal emitted by the acoustic emitter in the ambient noise signal.
    The acoustic emitter, according to a particular embodiment of the present invention, comprises the following elements: a first database configured to store a catalog of noise signals with different characteristics; a signal generating module configured to generate a noise signal based on selected characteristics of the first database; an amplifier module connected to the signal generator module; and a loudspeaker connected to the amplifier module and configured to emit the generated noise signal.
    The receiving device, according to a particular embodiment of the present invention, comprises: a detector microphone configured to receive the ambient noise signal; a processing module configured to extract the identifying characteristic of the noise signal emitted by the acoustic emitter; in response to the feature
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    identifying, select a noise cancellation signal that corresponds to the noise signal emitted in contraphase; and provide the selected noise cancellation signal; and a speaker configured to emit the noise cancellation signal provided by the processing module.
    The processing module, according to a particular embodiment of the invention, comprises: a module for extracting characteristics of the ambient noise signal received by the detector microphone; a second database with information on the characteristics of the catalog's noise signals stored in the first database (where the information in the second database contains the same information as the first database or at least part of it ); and a signal re-generator module configured to generate a noise cancellation signal from the information in the second database.
    In one of the embodiments of the invention it is contemplated to arrange the detector microphone on an outer face of the earpiece bowl and arrange the loudspeaker on an inner face of the earpiece bowl.
    Additionally, the present invention contemplates in one of its embodiments an error microphone disposed on the inner face of the headset, configured to receive a noise signal comprising the ambient noise signal and the generated noise cancellation signal, and where the module The processing module further comprises a feedback loop configured to power an adaptive controller with the noise signal received by the error microphone, where the adaptive controller is also fed from the signal re-generator module.
    Unlike other solutions of the state of the art, where it is usually intended to eliminate all the external noise that penetrates the earpiece, the present invention intends, according to all the above, to carry out an active noise control exclusively
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    for a type of sound, generated expressly and artificially to interfere with the perception of the environment of any other user in the coverage area.
    The advantages of the present invention are multiple and depending on the application scenario they become more or more important, but in general some can be highlighted such as: the generation, by the acoustic emitter, of an intimidating and / or dissuasive sound that generates discomfort and annoying an intruder, as well as hindering the execution of tasks and their communications; masking of existing sounds in the coverage area of the acoustic emitter; derived from the above, the reduction of situational awareness in the coverage area of the acoustic emitter; the relative improvement of the situational awareness of the carriers of the invention against those who do not carry it; the improvement of acoustic privacy for the bearers of the invention compared to other listeners; and integration with other communication systems.
    BRIEF DESCRIPTION OF THE FIGURES
    To complete the description of the invention and in order to help a better understanding of its characteristics, in accordance with a preferred example of its realization, a set of drawings is attached where, for illustrative and non-limiting purposes, represented the following figures:
    - Figure 1 shows a general block diagram of an acoustic unit of the present invention.
    - Figure 2 shows a block diagram of an embodiment of an acoustic unit, with detail of the control unit.
    - Figure 3 shows exemplary headphones of a receiving device of the present invention.
    - Figure 4 shows a block diagram with detail of the signal flows that interact with the headphones and detail of the processing unit.
    - Figures 5A, 5B and 5C represent the effect of canceling signals in counter phase.
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    DETAILED DESCRIPTION OF THE INVENTION
    The present invention discloses a method and system for the selective cancellation of noise in an acoustically degraded environment by a high intensity noise (generated by the invention itself) that masks, at least in part, the rest of the ambient sounds in the area of coverage.
    The system comprises a sound emission system, which generates said masking noise and thus produces an opaque acoustic environment that conceals ambient sounds, and a receiving device, preferably headphones, designed to eliminate the masking noise generated by the sound emission system. .
    The masking noise has a structure that allows simple detection by the receiving device of the invention. Thus, the frequency and dynamic characteristics that are selected for the catalog correspond to stationary noises, or at most with various stationary phases, with discrete frequency components (tonal signals), instead random noises that are more complicated to detect and cancel.
    In one of the embodiments of the invention, before selecting a noise signal from those available in the signal catalog of the sound emission system, the ambient sound is previously captured and one or more of its characteristics are analyzed for, depending on from them, select the most appropriate noise signal from those available in the catalog. For example, the intensity of the ambient noise can be measured with a sound level meter and, according to the measured intensity, determine the intensity of the masking noise to be emitted. Normally the intensity of the masking noise is set to a value equal to or greater than that of the detected ambient sound, but in some embodiments the intensity of the masking noise is set to a lower value than the detected intensity of the ambient sound so that this noise is not very clear. On the other hand, although the intensity of the masking noise is less than that of the ambient sound, the masking effect continues to occur in part, although obviously to a lesser extent.
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    Alternatively, in a particular embodiment of the invention, this masking noise is generated with a relatively high intensity, which allows most of the ambient sounds to be masked without the need to analyze them in advance. Preferably, the sound pressure level at 1 meter from the acoustic emitter is in a range between 60 dB (for example, the level of a normal conversation) and 100 dB (for example, intense traffic situation or sirens), strip of sound with known effect on the level of attention and concentration of people, although it could rise to 120 dB in some cases. Since the perception of sound varies with frequency, depending on the frequency different levels of sound are necessary to produce the same effect in the human ear.
    The combination of the sound emission system with the headphones causes a scenario, in the area of coverage of the masking noise, in which the situational awareness of people without headphones is greatly affected, while the headphones users, according to the In the present invention, they remain immune to masking noise. That is, the users of the headphones of the present invention will maintain their situational auditory awareness, listening to all the sounds existing in the area, except for the one that generates the masking noise, while the rest of the people in the coverage area will only hear the noise masker
    In a scenario with very high intensity ambient sound, the masking noise may not completely hide said ambient sound, but in cases where the ambient sound itself makes any communication impossible, it would have no effect trying to mask the ambient sound from third parties. . That is, the utility and the advantageous effects of the present invention are limited to scenarios or moments in which the ambient noise is maintained within certain intensity limits in relation to the sound level emitted by the acoustic emitter and the position it occupies.
    An example of an acoustic unit of the present invention is shown in Figure 1, which comprises a control unit 2, an amplifier 3 and a speaker 4. In a preferred embodiment of said acoustic unit, shown in Figure 2, the control unit
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    It consists of a database 5, which stores a catalog of masking noises (or noise patterns) and their associated characteristics (such as type, frequency, tonal components, amplitude, phase ...) and a generator module 6 of the masking pattern, which generates from the characteristics associated with the selected noise of the database the signal of the corresponding emnascarador pattern. This signal is delivered to the amplifier 3 and finally the masking noise 7 is emitted from the speaker 4 at the desired intensity, causing the sound environment to be masked in the coverage area. Each pattern will emit a series of frequencies, with a relation of intensities, and a temporal evolution.
    The coverage area is defined by the spatial distribution of the acoustic units, the characteristics of the masking noise (such as intensity, frequency, type.) And the type of sound source used, where according to different embodiments, for example sound sources are contemplated omnidirectional, which emit sound equally in all directions of space, or direct sound sources, which manage to concentrate a maximum of acoustic power in a specific direction.
    The receiving device preferably consists of an atrial type device. The headphones, in combination with the signal generated by the acoustic units described above, perform active noise control. The objective is to generate an “anti-noise” signal in contrast to the previously generated masking noise and that, being the user within the coverage area, will be present in the headphone bowl.
    The sound existing in the coverage area of the invention is represented in Figure 5.A Said existing sound is composed of the set of pre-existing sounds in the area (ambient sound 40) plus a masking sound 7 that adds the invention . The masking sound generated by the invention consists of an acoustic signal produced by the vibration of the air with certain temporal characteristics. In a synchronized way, the headphones generate an acoustic signal of selective cancellation of the masking sound (anti-noise 8) which, inside the headphones, adds to the sound there
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    existing. While in headphones with conventional active noise control, the anti-noise must be adjusted in such a way that it causes an opposite effect (in contraphase) to the noise existing in the headphones, so that the waves in contraphase are annulled, in the present invention , the anti-noise only cancels the part that corresponds to the masking noise that the invention itself generates, such that a user in the coverage area using the headphones with the selective cancellation signal of the masking sound, such and as shown in Figure 5.C, it only perceives the ambient sound 40 since the masking sound 7 is canceled inside the earpiece by said selective cancellation signal of the masking sound 8, since both signals are identical but of opposite sign . On the contrary, a user in the coverage area that does not use the headphones of the present invention, receives, as shown in Figure 5.B, the signals corresponding to ambient sound 40 plus masking noise 7, which means that you will only perceive the masking sound, since it hides the ambient sound.
    The "anti-noise" signal, which is generated in the headphones of the present invention, only seeks to cancel the effect of the masking noise, thus advantageously allowing the user to listen to the headphones of the rest of the sounds existing in the coverage area. . For this reason, it is essential to have a reference signal related to the masking sound.
    Figure 3 shows headphones 30 with an example configuration, where on an external face 31 of the bowl 32 there is a detector microphone 33 from which to obtain the wanted reference signal. The detector microphone captures the sound environment existing outside said bowl, that is, the ambient noise plus the masking noise generated. Inside the bowl there is a processing unit 34, which detects the presence of the masking sound in the sound environment signal and determines and regenerates the emission pattern used by the acoustic emitters. An error microphone 36 (which could be dispensed with in certain static scenarios or if a partial cancellation is acceptable), which determines the level of masking noise that is maintained inside the interior of the headphone, is disposed on an inner face 35 of the earpiece bowl. headset and therefore listens to the user in their headphones, despite the cancellation signal emitted from a speaker
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    37 arranged on the inside of the earpiece bowl. Additionally, in one of the embodiments, the process unit also amplifies the rest of the surrounding sounds.
    Figure 4 shows a block diagram of the components of the handset, according to an embodiment of the invention and the signal flows involved. Thus, an ambient noise 40 and the masking noise 7 generated by one or more acoustic emitters are naturally combined in the coverage area and are picked up by the detector microphone 33 of the headset as a single sound environment. The detector microphone captures this sound environment and delivers the signal to the processing unit 34, specifically to a feature extraction module 41.
    The feature extraction module performs a temporal and frequency analysis of the signal, to detect in it patterns that reveal the presence of masking noise in the sound environment signal. For this, a characteristic vector is obtained that contains the measured values of a series of selected parameters, such as type of noise, tonal components or phase, at all possible frequencies to determine the relationship between them, as well as the temporal structure From the analysis of these measurements, the resemblance between the sound being received and the sounds available in the database 43 is determined. If the resemblance exceeds a preset threshold, the masking noise is considered detected and, in that case, from the characteristics extracted, the emission pattern used by the acoustic emitter is determined, by means of a re-generator module 42 with access to the database 43 in which a catalog of masking noises and their associated characteristics have been previously stored (as per example, type, frequency, tonal components, amplitude, phase ...).
    The re-generator module of the masking pattern delivers the reference signal to an adaptive controller 44. The reference signal is generated from the characteristics defined in the masking noise catalog 43, and is adjusted according to the characteristics detected in the feature extraction module 41. Said regenerated signal will be equivalent to the presence of masking noise inside the headphones with the invention deactivated, but in phase opposition, to act as anti
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    noise. This active noise control is carried out by means of an adaptive feedforward algorithm, with the aim of nullifying the influence of masking noise in the earpiece bowl.
    At the output of the adaptive controller, the anti-noise or noise cancellation signal is generated, which is emitted by the loudspeaker 37 of the earpiece in contraphase with the masking noise signal, so that the acoustic interference that is generated eliminates the presence of the masking sound inside the headset.
    The error microphone 36 allows a fine adjustment of the selective noise cancellation by establishing a feedback loop 46 in the processing unit that adapts the operation of the controller 44. Although the interference caused by the cancellation signal generated by the re-generator module 42 pursues the complete cancellation of the masking noise, there are circumstances that affect the behavior, such as user movements or their orientation, which can cause changes in amplitude and phase of the perceived masking sound, with the result that a part of the masking noise is not annulled inside the headset and therefore reaches the user's ears. The arrangement of the error microphone on the inner face of the earpiece bowl thus allows to capture the noise signal present inside the earpiece and provide it to the feedback loop 46, so that the presence of masking noise is minimized in the earpiece. The feedback loop, which is a second input for the adaptive controller, has an operation similar to that described above, that is, a feature extraction module 47 receives the signal picked up by the error microphone and detects the presence of the masking noise, or at least part of it, in said signal. It extracts the main characteristics (type, tonal components, phase ...) and, from the extracted characteristics, determines the emission pattern used by the acoustic emitter, by means of a re-generator module 48 with access to a database 49 in which a catalog of masking noises and their associated characteristics have been previously stored (such as type, frequency, tonal components, amplitude, phase.). Thus the entire system will be immune to variations in the pattern, amplitude and phase that occurs in the user's movements through the coverage area.
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    As a result of the configuration and operation described above, the generated masking noise is canceled inside the headset, and the user will only hear the sounds of the environment, while the rest of the people in the coverage area of the acoustic emitters see reduced your hearing and situational awareness due to the effect of masking noise.
    In one of the embodiments of the invention, a communication layer is incorporated into the headphones, providing a possible communication signal 50, originated by another user and transmitted wirelessly, which is combined in the processing unit with the output signal. of the adaptive controller before being both delivered to the headphone output speaker for broadcast.
    In one of the embodiments of the invention, which improves the perception of ambient sound users, the processing unit amplifies the signal obtained by the error microphone 36 in an amplifier 51. The output signal of the amplifier 51 is delivered, by on the one hand, to the adaptive controller 44 after passing through the feedback loop 46 and, on the other hand, to the input of the speaker 37 directly. In this way, the speaker receives at its input a signal that results from the sum of two different signals: the cancellation signal generated by the re-generator module 48 and the signal obtained by the amplified error microphone (which contains the signal of ambient sound and the part of the masking noise that has not been canceled). As a result of this sum of signals, the cancellation signal emitted by the loudspeaker actually contains not only the contraphase signal corresponding to the part of the masking noise present, but also contains part of the ambient sound signal, in phase, for join the ambient sound signal inside the headset and provide the user with a higher intensity signal.
    The use protocol of the present invention comprises: firstly, the location of the masking sound source in the coverage area that is to be defined by spatially distributing one or more acoustic emitters therethrough; the selection of the masking noise pattern, which can be voluntary or can be done randomly; the sound source drive, to start emitting noise
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    masking and generate some noise pollution in the coverage area; the operation of the headphones by the user; and fine adjustment of the headphones, to achieve maximum efficiency depending on the user and specific characteristics of the fixing of the headphones, where the user can perform a manual adjustment (small scale) in the amplitude and / or phase of the signal cancellation (anti-noise), to optimize the cancellation effect depending on the fixation of the headphones on your head.
    Among the possible applications of the present invention, three of them are listed by way of example:
    In a first scenario, two users want to have a private conversation, but the environment around them offers no guarantee for it. The present invention advantageously provides them with the privacy they want by avoiding eventual listening by a third party. Users can choose to go to a closed enclosure, where several acoustic emitters that provide a perfectly defined coverage area are already installed, or opt for a portable acoustic emitter that they can use anywhere. Once each of them is provided with the headphones of the present invention, activating the acoustic emitter will generate a masking noise that will make it impossible for third parties to detect the private conversation of the two users, since the intensity of the masking noise is much greater than Private conversation The two users can keep their conversation with total privacy and in a normal volume, since for them the masking noise is imperceptible thanks to the selective noise cancellation signal that is generated in their headphones, fully synchronized with the emission patterns of the Acoustic emitters
    In a second scenario, the present invention is integrated into a home alarm system. The acoustic emitter of a traditional alarm is replaced by an acoustic emitter according to the present invention, or is complemented, so that the emitted alarm sound is selected from a catalog of sounds whose characteristics are previously known. Upon detection by an intruder's alarm system, the emission of a selected high intensity noise begins which, in addition to the
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    Traditional objectives of deterring the intruder by letting him know that he has been detected and requesting help from neighbors or police in the vicinity of the house, adds the objective of acoustically stunning him by masking the rest of the ambient sounds.
    Advantageously, the owner of the home, using the headphones of the present invention and thanks to the synchronization with the alarm sound (fully characterized and previously known) emits a cancellation signal of said sound in the headphones. Thus, the owner increases his security in case of looking for an escape route, since he is immune to the alarm noise, but he can perfectly hear the other ambient sounds generated by the intruder, such as footsteps or doors, and avoid confrontation. At the same time, thanks to the masking noise emitted by the alarm, the owner remains acoustically "invisible" in the face of the intruder.
    In a third scenario, the invention has application in police and military operations. The objective is similar to that described in the case of use in a home alarm system, since users (combatants) who use the system will obtain a relative improvement in their hearing in an environment acoustically degraded by high intensity masking noise issued. The noise produced by combatants during operations can betray their presence. The presence of the masking noise hides all sound associated with such performances (referred to a visual concept, the effect achieved is equivalent to becoming night). Thus, by using the headphones of the invention, it is possible to overcome this difficulty to the users of said headphones, so that their actions are hidden by being masked by noise, while said users continue to be able to hear the rest of the sounds of ambient.
    The coverage area can be defined in different ways. Acoustic emitters can be distributed in an area where a confrontation is anticipated or portable acoustic emitters can be used to prevent an unexpected confrontation. When activating the acoustic emitters, the ambient sound is inaudible for people who do not use the headphones of the invention, so those who do use them can, among other advantages, communicate privately.
    The present invention should not be limited to the embodiment described herein. Other configurations can be made by those skilled in the art in view of the present description. Accordingly, the scope of the invention is defined by the following claims.
    权利要求:
    Claims (12)
    [1]
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    1. Method for selective noise cancellation characterized by comprising the following steps:
    a) emit, by an acoustic emitter (1), a previously known noise signal (7);
    b) receive, in a receiving device (30), an ambient noise signal, where the ambient noise signal comprises the noise signal (7) emitted by the acoustic emitter;
    c) extracting, at the receiving device (30), at least a first identifying characteristic of the noise signal emitted by the acoustic emitter (1);
    d) in response to the first identifying characteristic, select a first noise cancellation signal that corresponds to the noise signal (7) emitted in contraphase;
    e) provide, at an output of the receiving device, the first noise cancellation signal selected, which cancels, at least in part, the noise signal emitted by the acoustic emitter, in the ambient noise signal.
    [2]
    2. Method according to claim 1 wherein emitting the noise signal comprises the previous steps of:
    - provide a first database (5) with a catalog of noise signals associated with different characteristics;
    - select a noise signal from those provided to the first database;
    - generate the selected noise signal according to its associated characteristics;
    Y
    - amplify the generated signal.
    [3]
    Method according to any of the preceding claims, which further comprises adapting the selected noise cancellation signal by means of an adaptive controller (44) fed back from an error microphone (36) disposed in the receiving device.
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    [4]
    4. Method according to claim 3 wherein feedback the adaptive controller comprises:
    - receiving, by the error microphone, a noise signal comprising the ambient noise signal and the first noise cancellation signal generated, where at least a part of the signal emitted by the acoustic emitter has not been fully canceled by said first cancellation signal;
    - extract at least a second identifying characteristic of the noise signal emitted by the acoustic emitter;
    - in response to the second identifying characteristic, select a second noise cancellation signal; Y
    - provide the adaptive controller with the second selected noise cancellation signal, to cancel in the noise signal received by the error microphone the part of the signal emitted by the acoustic emitter not canceled by the first cancellation signal.
    [5]
    5. Method according to any of the preceding claims, wherein the first cancellation signal provided at the output of the receiving device interferes with the ambient noise signal, which further comprises:
    - receive a generated noise signal on the receiving device as a result of interference from the ambient noise signal and the first cancellation signal; Y
    - amplify in the receiving device the noise signal received in the previous step.
    [6]
    6. System for selective noise cancellation characterized by comprising:
    - an acoustic emitter (1) configured to emit a previously known noise signal;
    - a receiving device (30) configured to receive an ambient noise signal, where the ambient noise signal comprises the noise signal emitted (7) by the acoustic emitter; extract at least one identifying characteristic of the noise signal emitted by the acoustic emitter; in response to the identifying characteristic, select a noise cancellation signal that corresponds to the noise signal emitted in contraphase; provide on one way the cancellation signal of
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    selected noise, to cancel the noise signal emitted by the acoustic emitter in the ambient noise signal.
    [7]
    7. System according to claim 6, wherein the acoustic emitter comprises:
    - a first database (5) configured to store a catalog of noise signals with different characteristics;
    - a signal generator module (6) configured to generate a noise signal based on selected characteristics of the first database;
    - an amplifier module (3) connected to the signal generator module; Y
    - a loudspeaker (4) connected to the amplifier module and configured to emit the generated noise signal.
    [8]
    8. System according to any one of claims 6-7, wherein the receiving device comprises:
    - a detector microphone (33) configured to receive the ambient noise signal;
    - a processing module (34) configured to extract the identifying characteristic of the noise signal emitted by the acoustic emitter; in response to the identifying characteristic, select a noise cancellation signal that corresponds to the noise signal emitted in contraphase; and provide the selected noise cancellation signal; Y
    - a loudspeaker (4) configured to emit the noise cancellation signal provided by the processing module.
    [9]
    9. System according to claim 8, wherein the processing module comprises:
    - a feature extraction module (41) of the ambient noise signal received by the detector microphone;
    - a second database (43) with information on the characteristics of the catalog's noise signals stored in the first database; Y
    - a signal re-generator module (42) configured to generate a noise cancellation signal from the information in the second database.
    [10]
    10. System according to any of claims 6-9 wherein the receiving device is wireless headphones.
    [11]
    11. System according to claims 8 and 10, wherein the detector microphone is arranged on an outer face (31) of the bowl (32) of the earpiece and the speaker is
    5 arranged on an inner face (35) of the earpiece bowl.
    [12]
    12. System according to claims 9 and 10, further comprising an error microphone (36) disposed on the inner face of the headset, configured to receive a noise signal comprising the ambient noise signal and the signal cancellation signal. generated noise, and where the module the processing module further comprises a loop of
    10 feedback (46) configured to power an adaptive controller (44) with the noise signal received by the error microphone, where the adaptive controller is also fed from the signal re-generator module (42).
    fifteen
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    ES2663650B2|2019-03-25|
    引用文献:
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