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DESCRIPTION JP2016536946

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DESCRIPTION JP2016536946
Abstract Generally, techniques for limiting active noise cancellation output are described. As an
example, an apparatus comprising one or more processors can perform the techniques. One or
more processors dynamically apply active noise cancellation to at least a portion of the audio
signal to obtain at least a portion of the active noise canceled version of the audio signal when
the estimated noise level rises. It can be configured to lower.
Active noise cancellation output limitation
[0001]
[0001]
This application claims the benefit of US Provisional Patent Application No. 61 / 890,833, filed
October 14, 2013.
[0002]
The present invention relates to the processing of audio signals, and more particularly to
applying active noise cancellation to audio signals.
[0002] [0003] Some computing devices (eg, cell phones, smart phones, headphones, music
players, etc.) may be used in noisy environments. For example, cell phones may be used at
airports where environmental noise, background noise or ambient noise may distract the user.
For example, the user may be calling while others are talking nearby or when the aircraft is
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1
taking off. These environmental noises can make it difficult for the user of the computing device
to hear the audio signal (eg, speech, music, etc.) output from the computing device. Active noise
cancellation refers to a method of adjusting the audio signal taking into account environmental
noise, background noise or ambient noise.
[0003]
[0004] In general, techniques for limiting active noise cancellation output are described.
[0004]
[0005] In one aspect, the method dynamically adjusts the application of active noise cancellation
to at least a portion of the audio signal to obtain at least a portion of the active noise canceled
version of the audio signal based on the estimated noise level. Prepare for.
[0005]
[0006] In another aspect, the apparatus dynamically adjusts the application of active noise
cancellation to at least a portion of the audio signal to obtain at least a portion of the active noise
canceled version of the audio signal based on the estimated noise level. And one or more
processors configured to:
[0006]
[0007] In another aspect, an apparatus includes at least a portion of an audio signal to obtain an
active noise canceled version of the audio signal based on the means for determining at least a
portion of the audio signal and the estimated noise level. And means for dynamically adjusting
the application of active noise cancellation to the part.
[0007]
[0008] In another aspect, the non-transitory computer readable storage medium, when executed,
is for acquiring at least a portion of an active noise canceled version of the audio signal based on
the estimated noise level. An instruction is stored that causes the one or more processors to
dynamically adjust the application of active noise cancellation to at least a portion.
[0008]
[0009]
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Details regarding one or more aspects of the techniques are set forth in the accompanying
drawings and the description below.
Other features, objects, and advantages of the techniques will be apparent from the description
and drawings, and from the claims.
[0009]
[0010]
FIG. 1A is a block diagram illustrating an example of an ANC apparatus that includes a
feedforward ANC filter and a reference microphone positioned to detect ambient noise.
[0011]
FIG. 1B is a block diagram illustrating an example of an ANC device that includes a feedback ANC
filter and an error microphone positioned to detect the sound produced by the loudspeaker.
[0012]
FIG. 2A is a block diagram illustrating a finite impulse response (FIR) implementation of a
feedforward ANC filter.
[0013]
FIG. 2B is a block diagram illustrating an alternative implementation of the FIR filter.
[0014]
FIG. 3 is a block diagram illustrating an infinite impulse response (IIR) implementation of the
filter.
[0015]
FIG. 4 is a block diagram illustrating an ANC device that can be configured to implement various
aspects of the limited ANC output techniques described in this disclosure.
[0016]
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FIG. 5 is a block diagram illustrating the limit control block shown in the example of FIG. 4 in
more detail.
[0017]
FIG. 6A is a block diagram illustrating an ANC apparatus implementing an adaptive ANC (AANC)
that can be limited or adjusted according to various aspects of the techniques described in this
disclosure.
[0017] FIG. 6B is a block diagram illustrating an ANC apparatus that implements adaptive ANC
(AANC) that can be limited or adjusted according to various aspects of the techniques described
in this disclosure.
[0017] FIG. 6C is a block diagram illustrating an ANC apparatus that performs adaptive ANC
(AANC) that can be limited or adjusted according to various aspects of the techniques described
in this disclosure.
[0018]
FIG. 7 is a block diagram illustrating another variation of a limit control block that performs
noise estimation, among other things, on error speech signals, in accordance with various aspects
of the techniques described in this disclosure.
[0019]
FIG. 8A is a block diagram illustrating an example ANC apparatus implementing an ANC that can
be limited or adjusted according to various aspects of the techniques described in this disclosure.
[0019] FIG. 8B is a block diagram illustrating an example ANC apparatus implementing an ANC
that can be limited or adjusted according to various aspects of the techniques described in this
disclosure.
[0019] FIG. 8C is a block diagram illustrating an example ANC apparatus implementing an ANC
that can be limited or adjusted according to various aspects of the techniques described in this
disclosure.
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[0020]
FIG. 9 is a block diagram illustrating the limit control block CB34 'of the example of FIG. 8 in
more detail.
[0021]
FIG. 10 is a block diagram illustrating another example ANC apparatus implementing an ANC
that can be limited or adjusted according to various aspects of the techniques described in this
disclosure.
[0022]
FIG. 11 is a schematic diagram illustrating the limit control block of the example of FIG. 9 in
more detail.
[0023]
FIG. 12 is a flow chart illustrating the exemplary operation of an ANC device configured to
implement various aspects of the techniques described in this disclosure.
[0010] [0024] The devices, apparatuses, systems and methods disclosed herein can be applied to
various computing devices. Examples of computing devices are mobile phones, smart phones,
headphones, video cameras, audio players (e.g. Moving Picture Experts Group-1 (MPEG-1) or
MPEG2 Audio Layer 3 (MP3) players), video players Audio recorder, desktop computer / laptop
computer, personal digital assistant (PDA), game play system, etc. One type of computing device
is a communication device that can communicate with other devices. Examples of communication
devices include phones, laptop computers, desktop computers, cell phones, smart phones,
electronic readers, tablet devices, gameplay systems, and the like.
[0011] [0025] Computing devices or communication devices may be selected from several
industry standards, such as the International Telecommunications Union (ITU) standard and / or
the Institute of Electrical and Electronics Engineers (IEEE) standard (eg, 802.11a, 802.11b,
802.11g, It can operate in accordance with wireless fidelity or "Wi-Fi" standards such as 802.11n
and / or 802.11ac. Other examples of standards to which communication devices can conform
are IEEE 802.16 (e.g., Global Interoperability for Microwave Access or "WiMAX"), Third
Generation Partnership Project (3GPP (R)), 3GPP The communication devices include, for
example, user equipment (UE), node B, evolved node B (eNB), long term evolution (LTE
(registered trademark)), global mobile communication system (GSM (registered trademark)) and
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others. Mobile devices, mobile stations, subscriber stations, remote stations, access terminals,
mobile terminals, terminals, user terminals, subscriber units, etc.). While some of the devices,
devices, systems and methods disclosed herein are described with respect to one or more
standards, the devices, devices, systems and methods apply to numerous systems and / or
standards. As possible, the techniques should not be limited to the scope of the present
disclosure.
[0012] [0026] It should be noted that some communication devices can communicate wirelessly
and / or can communicate using wired connections or links. For example, some communication
devices can communicate with other devices using the Ethernet protocol. The devices,
apparatuses, systems and methods disclosed herein may be applied to communication devices
that communicate wirelessly and / or communicate using wired connections or links.
[0013] [0027] As used herein, the terms "cancel", "cancel" and other variations of the word
"cancel" may or may not mean complete cancellation of the signal. For example, if the first signal
"cancels" the second signal, the first signal may interfere with the second signal in an attempt to
reduce the amplitude of the second signal. The resulting signal may or may not be reduced or
completely canceled.
[0014] [0028] As used herein, the terms "circuit", "circuitry" and other variations of the term
"circuit" can represent structural elements or components. For example, the circuit configuration
can be a collection of circuit components, eg, a number of integrated circuit components in the
form of processing and / or memory cells, units, blocks, and so on.
[0015] [0029] Traditionally, static or non-adaptive active noise control (ANC) consists of a
filtering operation and requires a noise signal input. Conventional non-adaptive ANCs can be
applied to handsets. In one example of a feedforward ANC, a noise microphone can be placed on
the back of the handset and a speaker (e.g., earpiece, receiver, etc.) can be placed on the front of
the handset and the user can see his / her ear Can be held near the The ANC process can use the
noise signal provided by the noise microphone in an attempt to cancel the noise by outputting
the signal from the speaker.
[0016] [0030] Adaptive ANC consists of both filtering and adaptation operations. Typically, the
adaptive algorithm for feed forward (FF) ANC requires an error signal input and measures the
remaining noise signal in the "quiet zone". Thus, a traditional adaptive FF ANC may require two
input signals. One input signal can include external noise, and the other input signal includes an
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error signal (eg, from an error microphone). The filtering operation may require only noise signal
input. However, the adaptation operation may require both a noise signal input and an error
signal input.
[0017] [0031] In one example of a typical adaptive ANC process, a noise microphone captures a
noise signal and an error microphone captures an error signal e (n). In general adaptive ANC
processing, the adaptive algorithm minimizes the error signal e (n), which causes the adaptive
filter W (z) to converge to an optimal solution. Converging adaptive filters can be referred to as
an iterative convergence or training process. In this example, W (z) = − P (z) / S (z), where P (z)
is the first transfer function (eg, primary path transfer function), and S (z) ) Is a second transfer
function (e.g., a secondary path transfer function).
[0018] [0032] Another example of traditional adaptive ANC processing is referred to as filtered x
least mean square (FxLMS) adaptive ANC processing. This approach also uses an error
microphone to capture the error signal e (n). The LMS algorithm uses the captured error signal e
(n) to train or converge the adaptive filter W (z).
[0019] [0033] In one example, a conventional adaptive ANC can be applied to the handset. In
this example, a noise microphone can be placed on the back of the handset, and a speaker (e.g.,
earpiece, receiver, etc.) can be placed on the front of the handset, the user near his / her ear Can
be held. The error microphone can also be placed on the front of the handset, near the speaker.
ANC processing can use the noise signal provided by the noise microphone and the error signal
provided by the error microphone in an attempt to cancel the noise by outputting the signal from
the speaker.
[0020] [0034] Implementing an adaptive ANC may be expensive (eg, in terms of processing
cycles and / or memory consumption), but may be useful in some applications. For example,
applying ANC to a handset earpiece or speaker benefits from adaptation, as the acoustic transfer
function is very dynamic and filter adaptation can be used to ensure optimal noise cancellation. It
can be one application of ANC that can be obtained.
[0021] [0035] Conventional feed forward (FF) adaptive active noise control (ANC) typically
requires an error microphone (or any other input sensor) to pick up the sound signal in the
"quiet zone". This sound signal is usually called an error signal. A microphone that receives the
error signal can typically be placed near a speaker (e.g., an earpiece, a receiver, etc.) to pick up
the error signal. In some instances, a microphone that receives an error signal can be used as an
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addition to other microphones used to pick up noise for the purpose of reduction (eg,
cancellation).
[0022] [0036] ANC or adaptive ANC (AANC) may, in some instances, increase the gain of the
audio signal output by the speaker due to the cancellation effect of applying ANC or AANC. That
is, when the external noise level is high, the resulting ANC / AANC signal can also have a high
level (meaning higher gain compared to the original signal). When the input noise level exceeds
some extreme level A (often expressed in acceptable decibel (dB) levels during the average
listening duration, “extreme” typically means the average listening duration ANC / AANC audio
signals may exceed level B above some threshold C (defined as the result of non-minimum
listening loss when exposed to these dB levels across Here, this threshold is also expressed in dB
over the average listening duration, and this threshold is set to avoid non-minimum listening loss
when exposed to these threshold dB levels over the average listening duration. Will be The
resulting ANC / AANC audio signals can cause potential problems, such as saturation in digital
systems, damage to speakers due to excessive excursions, damage to human hearing.
[0023] [0037] The techniques described in this disclosure may be used automatically when the
input noise level exceeds some predetermined dB threshold level (other than human intervention
intended to enable the techniques described in this disclosure). ANC / AANC output can be
turned off or reduced, which means not. The technique can provide a limit controller that adjusts
the ANC / AANC output automatically or dynamically based on the input noise level (e.g.,
detected via a noise microphone). The limit controller may receive an ANC noise input
microphone signal (or other microphone signal or ANC output signal) and control an ANC filter
gain based on the determined environmental noise level.
[0024]
[0038]
Various aspects of the technique can include a noise estimation unit that estimates noise based
on the noise microphone signal to determine an environmental noise level, and an ANC gain
control unit. The noise estimation unit uses an approach such as average amplitude, peak
amplitude, average power or any combination thereof, etc. The ANC / AANC input signal (or
output signal, or in some cases, in some cases) over a period of time The loudness of any other
microphone signal from which the noise estimate can be derived can be measured. For example,
when performing noise estimation using the mean amplitude, the noise estimation unit
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[0025]
[0026]
The average amplitude can be estimated by where X (t) represents the noise signal over time t
and N means the number of samples forming the noise signal X (t).
The noise estimation unit can estimate the noise level using peak power by calculating MAX (| X
(t) |), where MAX (<*>) function is the noise with maximum gain Return the gain values for the
samples of signal X (t).
[0027]
[0039]
The gain control unit may compare the estimated noise level to the threshold level C and turn off
or dynamically adjust the ANC when the estimated noise level exceeds the threshold level C. By
reducing the ANC output gain (or potentially setting the gain to zero to turn off the ANC), the
technique is against digital circuit saturation, speaker damage, and human hearing damage. Can
be protected.
[0028]
[0040]
FIG. 1A is a block diagram illustrating an example A10 of an ANC apparatus that includes a
feedforward ANC filter F10 and a reference microphone MR10 positioned to detect ambient
noise. A filter F10 is arranged to receive a reference noise signal SX10 based on the signal
generated by the reference microphone MR10 and to generate a corresponding antinoise signal
SY10. Apparatus A10 also includes a loudspeaker LS10 configured to generate an acoustic signal
based on the noise reduction signal SY10. The loudspeaker LS10 directs the acoustic signal to
the user's ear canal or into the user's ear canal so that ambient noise is attenuated or canceled
before reaching the user's tympanic membrane (also called "quiet zone") To be placed. Apparatus
A10 (for example, via a filter configured to perform spatially selective processing operations such
as beamforming, blind source separation, gain and / or phase analysis, etc.) from two or more
reference microphones MR10 Can also be implemented to generate the reference noise signal
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SX10 based on the information from the
[0029]
[0041]
As mentioned above, the ANC device can be configured to use one or more microphones (eg,
reference microphone MR10) to detect acoustic noise from the background. Another type of ANC
system uses a microphone (possibly in addition to a reference microphone) to pick up the error
signal after noise reduction. The ANC filter in a feedback arrangement is typically configured to
reverse the phase of the error signal, and to equalize the frequency response to integrate the
error signal, and / or to match the delay. It can also be configured to do or minimize.
[0030]
[0042]
FIG. 1B is a block diagram showing an example A20 of an ANC device including a feedback ANC
filter F20 and an error microphone ME10 arranged to detect sound in the user's ear canal, the
sound generated by the loudspeaker LS10 ( For example, an acoustic signal based on the noise
reduction signal SY10 is included. A filter F20 is arranged to receive an error signal SE10 based
on the signal generated by the error microphone ME10 and to generate a corresponding noise
reduction signal SY10.
[0031]
[0043]
In some examples, the ANC filter (eg, filter F10, filter F20) is configured to match the acoustic
signal in terms of amplitude and to generate an anti-noise signal SY10 that is opposite to the
acoustic signal in terms of phase. Ru. Signal processing operations such as time delay, gain
amplification, and equalization or low pass filtering may be implemented to achieve optimal noise
cancellation. In some instances, the ANC filter may be configured to high pass filter the signal
(eg, to attenuate high amplitude, low frequency acoustic signals). Additionally or alternatively, the
ANC filter may be configured to low pass filter the signal (eg, to reduce the ANC effect towards
higher frequencies). Because the noise reduction signal should be available by the time the
acoustic noise goes from the microphone to the actuator (ie loudspeaker LS10), the processing
delay due to the ANC filter takes a very short time (typically Should not exceed about 30 to 60
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microseconds).
[0032]
[0044]
The filter F10 comprises a digital filter so that the ANC device A10 can be configured to perform
an analog-to-digital conversion on the signal generated by the reference microphone MR10 to
generate the reference noise signal SX10 in digital form . Likewise, the filter F20 comprises a
digital filter, so that the ANC device A20 is arranged to perform an analog-to-digital conversion
on the signal generated by the error microphone ME10 to generate the error signal SE10 in
digital form Can. Examples of other preprocessing operations that can be performed by the ANC
apparatus upstream of the ANC filter in the analog and / or digital domain include spectral
shaping (eg, low pass, high pass, and / or band pass filtering) , Echo cancellation (eg, error signal
SE10), impedance matching, and gain control. For example, an ANC device (e.g., device A10) can
be configured to perform a high pass filtering operation (e.g., with a 50, 100 or 200 Hz cutoff
frequency) on the signal upstream of the ANC filter.
[0033]
[0045]
The ANC device may also include a digital-to-analog converter (DAC) arranged to convert the
noise protection signal SY10 into analog form upstream of the loudspeaker LS10. In some
instances, the ANC device mixes the desired sound signal (in either the analog domain or the
digital domain) with the anti-noise signal to generate an audio output signal for reproduction by
the loudspeaker LS 10 Can be configured. Examples of the desired sound signal include a
received (i.e., far end) voice communication signal, music or other multimedia signal, and a side
tone signal.
[0034]
[0046]
FIG. 2A is a block diagram illustrating a finite impulse response (FIR) implementation AF12 of
feedforward ANC filter AF10. In this example, the filter AF12 has a transfer function B (z) = b0 +
b1 <*> z <-defined by the values of the filter coefficients (i.e. feed forward gain coefficients b0, b1
and b2). It has 1> + b2 <*> z <-2>. Although a second-order FIR filter is shown in this example,
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the FIR implementation of filter AF10 relies on any number of FIR filter stages (ie, any number of
filter coefficients) depending on such factors as maximum allowable delay, etc. Can be included.
For the case where the width of the reference noise signal SX10 is one bit, each of the filter
coefficients can be implemented using a polarity switch (eg, an XOR gate).
[0035]
[0047]
FIG. 2B is a block diagram illustrating an alternative implementation AF 14 of FIR filter AF 12.
The feedback ANC filter AF20 can be implemented as a FIR filter according to the same principle
as described above with reference to FIG. 2A.
[0036]
[0048]
FIG. 3 is a block diagram illustrating an infinite impulse response (IIR) implementation AF 16 of
filter AF 10. In this example, the filter AF16 has a transfer function B (z) / (?) Defined by the
values of the filter coefficients (i.e. feedforward gain coefficients b0, b1, b2, and feedback gain
coefficients a1 and a2). 1-A (z) = b0 + b1 <*> z <-1> + b2 <*> z <-2> / (1-a1 <*> z <-1> -a2 <*>> z
<-2>). Although a second-order IIR filter is shown in this example, the IIR implementation of filter
AF10 either feedback (ie, the denominator of the transfer function) or feedforward (ie, the
transfer function), depending on factors such as maximum allowable delay, etc. , Any of the
transfer function molecules) can include any number of filter stages. For the case where the
width of the reference noise signal SX10 is one bit, each of the filter coefficients can be
implemented using a polarity switch (eg, an XOR gate). The feedback ANC filter AF20 can be
implemented as an IIR filter according to the same principle as described above with reference to
FIG. Both filters F10 and F20 can also be implemented as a series of two or more FIR and / or IIR
filters.
[0037]
[0049]
FIG. 4 is a block diagram illustrating an apparatus A50 that can be configured to implement
various aspects of the limited ANC output techniques described in this disclosure. The ANC
device A50 represents an example of the ANC device A10 described above in that the ANC device
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A50 includes an ANC filter F105 that may be similar or substantially similar to the ANC filter
F105 of the ANC device A10. Can. Although not shown in the example of FIG. 4, the ANC device
A50 includes a loudspeaker similar to the loudspeaker LS10 shown in the example of FIG. 1 and
a reference microphone similar to the reference microphone MR10 also shown in the example of
FIG. , Or can be coupled to a loudspeaker similar to loudspeaker LS10 shown in the example of
FIG. 1 and a reference mic similar to reference mic MR10 also shown in the example of FIG.
[0038]
[0050]
In the example of FIG. 4, the ANC device A 50 also includes a limit control block CB 34, which
may be configured to represent various aspects of the techniques described in this disclosure. it
can. The limit control block CB34 is an active noise of a reference noise audio signal SX10
obtained via a reference microphone, a voice audio signal SV10 obtained via a voice microphone
(can be different from the reference microphone), and a reference audio signal SX10 Canceled
version (can be called "active noise canceled voice signal SY10") and mixed output voice signal
SO10 (voice signal obtained as a result of mixing active noise canceled voice signal with
reproduced voice signal SP10 Can be received, retrieved, or determined. The playback audio
signal SP10 can represent an audio signal intended to be played back via the ANC device A50 or
some other device. The example of the reproduction audio signal SP10 represents a so-called
"desired" audio signal, for example, a music or other multimedia audio signal and an audio signal
of voice. The playback audio signal SP10 can be representative of the "desired" audio signal in
that it has a generally localized noise-free quality of the audio signal (the playback audio signal
SP10 can be, for example, a music or multimedia audio signal) (Meaning that it still has the
unintentionally interleaved noise) intentionally or non-locally, such as in voice speech signals
received from other communication devices).
[0039]
[0051]
The limit control block CB34 receives these signals SX10, SV10, SY10 and SO10 and can initially
make noise estimates for one or more of the signals SX10, SV10, SY10 and SO10. While
described as performing noise estimation, limit control block CB 34 can not perform noise
estimation in some instances, which is performed by a dedicated noise estimation block. In these
examples, limit control block CB 34 may receive noise levels estimated from the noise estimation
block, as described in further detail below. In any case, limit control block CB34 may perform
noise estimation on one or more of signals SX10, SV10, SY10 and SO10 to determine the
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estimated noise level. References to signals in this disclosure, for example, SX10, SV10, SY10 and
SO10, should be understood as referring to at least a portion of the signals, and not necessarily
to refer to the entire signal.
[0040]
[0052]
Continuing, the limit control block CB34 uses the approach method such as average amplitude,
peak amplitude, average power or any combination thereof, etc., signal SX10 over a period of
time (usually a multiple of the speech frame duration), The loudness of one or more of SV10,
SY10 and SO10 can be measured. For example, when performing noise estimation using the
average amplitude, the limit control block CB34
[0041]
[0042]
Can estimate the average amplitude, where X (t) represents a function of one or more of the
signals SX10, SV10, SY10 and SO10 over time t, and N forms the signal X (t) Means the number
of samples.
The limit control block CB34 can estimate the noise level using peak power by calculating MAX
(| X (t) |), where MAX (<*>) function has maximum gain Return the gain values for the samples of
the noise signal X (t).
[0043]
[0053]
Limit control block CB 34 may then compare the estimated noise level to one or more threshold
levels (sometimes referred to as "limits" in this disclosure). In some instances, limit control block
CB34 compares the estimated noise level to a single threshold level, and the estimated noise level
is above threshold level (or in some implementations, above threshold level) The application of
the ANC filter F105 to the reference audio signal SX10 can be dynamically adjusted. In other
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words, the limit control block CB34 can dynamically adjust the application of active noise
cancellation to the audio signal SX10 based on the estimated noise level. Limit controller block
CB34 adjusts this by adjusting the gain of ANC filter F105 (eg, by specifying new filter
coefficients for ANC filter F105 that results in lower gains for ANC filter F105). Adjustments can
be made.
[0044]
[0054]
FIG. 5 is a block diagram illustrating the limit control block CB34 shown in the example of FIG. 4
in more detail. In the example of FIG. 5, the limit control block CB34 includes a noise estimation
block 36, a noise comparison block 38, and a gain determination block 40. The noise estimation
block 36 may represent a unit configured to estimate the noise level from one or more of the
signals SX10, SV10, SY10 and SO10. Noise estimation block 36 may estimate the noise level
using a smoothing function and / or filtering.
[0045]
[0055]
In some examples, noise estimation block 36 may use more than one noise estimation algorithm
or model, where each noise estimation model is configured to estimate different types of noise
levels. Can. For example, noise estimation block 36 may include an ambient noise estimation
model for estimating general ambient noise levels. In this and other examples, the noise
estimation block 36 may also include a wind noise estimation model to estimate a particular type
of noise, ie wind noise, which properly estimates wind noise levels. In order to do so, two or more
of the signals SX10, SV10, SY10 and SO10 may be required. When employing more than one
noise estimation algorithm, the noise estimation block 36 may estimate the estimated noise level
NL 42 by two or more intermediate estimated noise levels output by the two or more noise
estimation algorithms. It can be formed as a function. In any case, the noise estimation block 36
can output the estimated noise level NL 42 to the noise comparison block 38.
[0046]
[0056]
Noise comparison block 38 may be representative of a unit configured to compare estimated
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noise level NL42 to threshold TH48. A user, manufacturer or developer may interface with the
user interface presented by ANC device A 50 or other device to configure noise comparison block
38 using threshold TH 48. In some examples, the threshold TH 48 may vary based on the type or
source of the audio signal to be reproduced (ie, the reproduced audio signal SP10 shown in the
example of FIG. 4). In other words, for a voice call in which the reproduced speech signal SP10
represents a voice speech signal, the noise comparison block 38 is configured to compare the
estimated noise level NL42 with the threshold TH48 specific to the voice speech signal. This
threshold TH48 can be higher than the threshold TH48 used when the user is trying to listen to
the audio signal of music. The noise comparison block 38 may output a flag FL44 to the gain
determination block 40 when the estimated noise level NL42 is greater than or equal to the
threshold TH48 (or, in some instances, exceeds the threshold TH48). This flag FL44 can indicate
that the gain determination block 40 reduce the gain associated with the ANC filter F105. In
some examples, this flag FL44 causes the gain determination block 40 to reduce the gain
associated with the ANC filter F105 to zero (effectively disabling the application of the ANC filter
FL44 to the reference audio signal SX10). Can be instructed. Whether the noise comparison
block 38 transmits the flag FL44 to reduce the gain associated with the ANC filter F105 or set it
to zero depends on the type or source of the reproduced speech signal SP10, the estimated noise
level NL42 or some other determination. It can be based on one or more of the criteria or
variables.
[0047]
[0057]
In some instances, the noise comparison block 38 may utilize more than one threshold TH48. In
these and other examples, the estimated noise level NL42 is one or more of the first one or more
of the thresholds TH48 (or, in some examples, the first one or more of the thresholds TH48 2.)
Sometimes, the noise comparison block 38 can transmit a first flag FL40 which indicates that the
gain determination block 40 reduces but does not disable the gain associated with the ANC filter
F105. The second one of the thresholds TH48 can be higher than the first one of the thresholds
TH48. The noise comparison block 38 when the estimated noise level NL42 is one or more of the
second one of the thresholds TH48 (or, in some instances, exceeds the second one of the
thresholds TH48). May output one of the flags FL 44 instructing the gain determination block 40
to reduce the gain associated with the ANC filter F 104 to zero. In this manner, the noise
comparison block 38 sends one or more flags FL44 to the gain determination block 40 to
indicate whether the gain determination block 40 should reduce the gain associated with the
ANC filter F 105 or set it to zero. Can be sent.
[0048]
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16
[0058]
Gain determination block 40 represents a unit capable of calculating the target gain for ANC
filter F 105 based on the comparison of estimated noise level NL 42 with one or more thresholds
TH 48 (this comparison is performed using flags FL 44 Effectively represented by one or more).
Gain determination block 40 may calculate this target gain to determine one or more filter
coefficients FC 46 that satisfy the target gain. Gain determination block 40 may then install these
filter coefficients FC 46 in ANC filter F 105. In this way, the gain determination block 40 can
effectively adjust the application of the ANC filter FL44 to the reference speech signal SX10
based on the estimated noise level NL42.
[0049]
[0059]
The gain determination block 40 may be configured to incrementally reduce the gain in some
instances, for example, over a series of X frames, over a predetermined time portion, where X is a
user, manufacturer And / or can be a configurable number set by the developer. In some
instances, the variable X can be set to have different values depending on the source and / or
type of the reproduced audio signal SP10. For example, the user can play a video game that relies
on the ANC device A50 to improve the experience by reducing or canceling noise, and the
application that is run to present the video game is the user's gameplay It is possible to set X to a
number suitable to maintain the listening experience consistently to not disturb the experience.
In these and other examples, gain determination block 40 reduces the gain by a percentage with
respect to each of the X frames, generates filter coefficients FC 46, and processes the next frame
of X frames These filter coefficients FC46 can be installed in the ANC filter F105 before.
[0050]
[0060]
Gain determination block 40 may also calculate target gain as a function of estimated noise level
NL 42 and threshold TH 48 in these and other examples. That is, gain determination block 40
may calculate the target gain as the difference between estimated noise level NL 42 and
threshold TH 48 in these and other examples. In some instances, the gain determination block 40
may calculate the target gain as a function of the estimated noise level NL42. In other words,
gain determination block 40 may utilize one or more mathematical functions with noise level NL
42 estimated as a variable in one or more of these functions to calculate a target gain. In some
16-04-2019
17
examples, the gain determination block 40 can use the estimated noise level NL 42 as a key into
a look-up table (LUT) and can return the target gain.
[0051]
[0061]
Noise estimation block 36 may continue to receive signals SX10, SV10, SY10 and SO10 to
determine an estimated noise level NL42. Noise estimation block 36 may output these recently
updated estimated noise levels to noise comparison block 38, which outputs one or more flags FL
44 in the manner described above. be able to. Gain determination block 40 continues to adjust
the application of ANC filter F 105 dynamically (or in other words automatically) based on these
flags 44, threshold 48 and / or estimated noise level 42. Can.
[0052]
[0062]
Over time, ambient noise, background noise, wind noise or other environmental noise may
decrease in volume (eg environmental noise while moving, eg siren of moving vehicle) or stop
completely At a point in time, noise determination block 36 may determine a recently updated
estimated noise level 42 that is lower than threshold TH48. When the estimated noise level 42 is
lower than each of the one or more applicable thresholds TH48, the noise comparison block 38
instructs the gain determination block 40 to return to the static form of the ANC filter F105. Flag
FL44 can be output. Gain determination block 40 may store or otherwise maintain original filter
coefficients FC 46 that are used when it is no longer desirable or necessary to limit the
application of ANC filter F 105. The gain determination block 40 may retrieve these filter
coefficients FC46 and install these filter coefficients FC46 in the ANC filter F105 in order to
dynamically retune the application of the ANC filter F105 to the state initially set. it can.
[0053]
[0063] In this manner, the technique allows the limit controller block CB 34 of the ANC device A
50 to obtain at least a portion of the active noise canceled version of the audio signal based on
the estimated noise level into at least a portion of the audio signal. It may be possible to adjust
the application of active noise cancellation dynamically.
[0054]
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18
[0064] In these and other examples, limit controller block CB34 dynamically adjusts the
application of active noise cancellation based on the estimated noise level to at least a portion of
the active noise canceled version of the speech signal. Application of non-adaptive active noise
cancellation to at least a portion of the audio signal can be dynamically adjusted to obtain.
[0055]
[0065] In these and other examples, limit controller block CB 34 dynamically reduces the gain of
at least a portion of the speech signal based on the estimated noise level when dynamically
adjusting the application of active noise cancellation. Can.
[0056]
[0066] In these and other examples, limit controller block CB 34 dynamically sets the gain of at
least a portion of the audio signal to zero based on the estimated noise level when dynamically
adjusting the application of active noise cancellation. can do.
[0057]
[0067] In these and other examples, limit controller block CB34 has active noise cancellation of
at least a portion of the reference noise audio signal based on the estimated noise level when
dynamically adjusting the application of active noise cancellation. The gain of the active noise
cancellation filter to be applied to at least a portion of the audio signal to output a version can be
dynamically adjusted.
[0058]
[0068] In these and other examples, limit controller block CB34 actively adjusts the noise of the
reference noise speech signal based on the difference between the estimated noise level and the
threshold level when dynamically adjusting the application of active noise cancellation. The gain
of the active noise cancellation filter to be applied to at least a portion of the audio signal to
output at least a portion of the encoded version may be dynamically adjusted.
[0059]
[0069] In these and other examples, the limit controller block CB34 is configured to dynamically
adjust the application of active noise cancellation based on a mathematical function of the
estimated noise level, the active noise canceled version of the speech signal. The gain of the
active noise cancellation filter to be applied to at least a portion of the audio signal to output at
least a portion can be dynamically adjusted.
16-04-2019
19
[0060]
[0070] In these and other examples, limit controller block CB 34 equals the gain determined
using the estimated noise level as a key into the look-up table when dynamically adjusting the
application of active noise cancellation. The gain of the active noise cancellation filter may be
dynamically adjusted to be at least a portion of the audio signal to output at least a portion of the
active noise canceled version of the audio signal. Ru.
[0061]
[0071] In these and other examples, limit controller block CB34 dynamically adjusts the
application of active noise cancellation based on the estimated noise level to at least a portion of
the active noise canceled version of the speech signal. The gain of the active noise cancellation
filter may be dynamically set to zero prior to applying the active noise cancellation filter to at
least a portion of the audio signal for output.
[0062]
[0072]
In these and other examples, limit controller block CB 34 may compare the estimated noise level
to the threshold level when dynamically adjusting the application of active noise cancellation.
In these examples, limit controller block CB34 is applied to at least a portion of the audio signal
to output at least a portion of the active noise canceled version of the audio signal when the
estimated noise level is greater than or equal to the threshold level. Dynamically adjust the gain
of the active noise cancellation filter.
[0063]
[0073]
In these and other examples, limit controller block CB34 outputs the first portion of the active
noise canceled version of the audio signal when the estimated noise level is greater than or equal
to the threshold level. The gain of at least the active noise cancellation filter to be applied to the
first part may be dynamically adjusted, the counter may be set to a value greater than one and
the value of the counter may be reduced by one.
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20
When the value of the counter is equal to zero, limit controller block CB 34 may determine
whether the recently updated estimated noise level exceeds the threshold level.
When the recently updated estimated noise level exceeds the threshold value, limit controller
block CB34 is applied to the second portion of the audio signal to output the second portion of
the active noise canceled version of the audio signal. The gain of the active noise cancellation
filter to be adjusted can be adjusted dynamically, the counter can be reset to a value greater than
one and the value of the counter can be reduced by one.
[0064]
[0074]
In these and other examples, limit controller block CB34 outputs the first portion of the active
noise canceled version of the audio signal when the estimated noise level is greater than or equal
to the threshold level. The gain of the active noise cancellation filter to be applied to at least the
first part can be dynamically adjusted, the counter can be set to a value greater than one and the
value of the counter can be reduced by one.
When the value of the counter is equal to zero, limit controller block CB34 may determine if the
recently updated estimated noise level exceeds the threshold level, and the recently updated
estimated noise level is less than the threshold value. Sometimes, the gain can be dynamically
reset to the value of the gain used before dynamically adjusting the gain of the active noise
cancellation filter.
[0065]
[0075]
In these and other examples, limit controller block CB 34 may enable dynamic adjustment of at
least a portion of the audio signal when the estimated noise level is greater than or equal to the
first threshold level.
In these and other examples, limit controller block CB 34 is an audio signal to output at least a
portion of the active noise canceled version of the audio signal when the estimated noise level is
16-04-2019
21
greater than or equal to the second threshold level. The gain of the active noise cancellation filter
to be applied to at least a portion of can be dynamically adjusted.
[0066]
[0076] In these and other examples, limit controller block CB 34 may perform noise estimation
on the reference noise speech signal to obtain an estimated noise level.
[0067]
[0077] In these and other examples, limit controller block CB 34 may determine the estimated
noise level as the average amplitude of at least a portion of the reference noise audio signal when
making noise estimation.
[0068]
[0078] In these and other examples, limit controller block CB 34 may determine the estimated
noise level as the peak amplitude of at least a portion of the reference noise audio signal when
making noise estimation.
[0069]
[0079] In these and other examples, limit controller block CB 34 may determine the estimated
noise level as the average power of at least a portion of the reference noise audio signal when
making noise estimation.
[0070]
[0080] In these and other examples, limit controller block CB 34 may perform non-wind noise
estimation on the reference noise audio signal to obtain an estimated noise level when
performing noise estimation.
[0071]
[0081] In these and other examples, limit controller block CB 34 may perform wind noise
estimation on the reference noise audio signal to obtain an estimated noise level when
performing noise estimation.
[0072]
[0082] In these and other examples, limit controller block CB34 performs non-wind noise
16-04-2019
22
estimation on the reference noise audio signal to obtain a first estimated noise level when
performing noise estimation, and second estimation Wind noise estimation may be performed on
the reference noise speech signal to obtain a noise level, and the estimated noise level may be
determined as a function of the first estimated noise level and the second estimated noise level.
[0073]
[0083] In these and other examples, limit controller block CB 34 may perform noise estimation
for at least a portion of the voice signal of the voice obtained using the voice microphone when
performing noise estimation.
[0074]
[0084] In these and other examples, limit controller block CB 34 may perform noise estimation
for at least a portion of the reference noise audio signal obtained using the reference microphone
different from the voice microphone when performing noise estimation.
[0075]
[0085] In these and other examples, limit controller block CB34 uses at least a portion of the
reference noise speech signal and the voice microphone obtained using the reference
microphone to determine the estimated noise level when performing noise estimation. Noise
estimation can be performed on at least a portion of the speech signal of the voice obtained using
it.
[0076]
[0086] In these and other examples, limit controller block CB 34 may perform noise estimation
on the mix of at least a portion of the active noise canceled version of the audio signal mixed with
the reproduced audio signal when performing noise estimation. .
[0077]
[0087]
In some instances, the playback audio signal comprises a music audio signal.
In another example, the playback audio signal comprises a voice audio signal.
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23
In yet another example, the playback audio signal comprises a multimedia audio signal.
[0078]
[0088]
In various examples, one or more of the examples described above can be implemented with
respect to one another.
In other words, references to these and other examples above can be understood to mean that
although these examples are described as separate examples, they can be implemented in any
reasonable combination.
[0079]
[0089]
6A-6C are block diagrams illustrating ANC devices A60 and A62 implementing adaptive ANC
(AANC), which may be limited or adjusted according to various aspects of the techniques
described in this disclosure.
Apparatus A60 shown in the example of FIG. 6A can represent other variations of apparatus A20
and can be similar to ANC apparatus A50.
While similar to the ANC device A50, the ANC device A60 can receive an additional noise speech
signal SN10 detected or obtained by an error microphone, for example the error microphone
ME10 shown in the example of FIG. 1B. .
As shown in the example of FIG. 1B, the error microphone ME10 can be spatially close to the
loudspeaker LS10 to sample or obtain a representation of the sound emitted by the loudspeaker
LS10 in the form of a noise speech signal SN10.
[0080]
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24
[0090]
As shown in the example of FIG. 6A, the limit control block CB34 can receive an additional audio
signal SE10, which is an output audio signal SO10 of the ANC device A60 and of the noise audio
signal SN10. The error speech signal SE10 calculated as a function can be represented.
That is, the ANC device A60 can calculate the error voice signal SE10 as the difference between
the output voice signal SO10 and the noise voice signal SN10 (including buffering the output
voice signal SO10 during the same or substantially the same period) be able to).
Limit control block CB34 may utilize error speech signal SE10 when making noise estimates, as
described below with respect to FIG.
[0081]
[0091]
FIG. 6B is a block diagram illustrating an ANC apparatus A 62 that implements an adaptive ANC
(AANC) that can be limited or adjusted according to various aspects of the techniques described
in this disclosure.
The ANC device A62 may be substantially similar to the ANC device A60, but the ANC device A62
includes an additional echo cancellation (EC) filter EC10.
The EC filter EC10 can perform echo cancellation filtering on the reproduced audio signal SP10.
The echo cancellation filter EC10 can perform any form of echo cancellation, including one or
more of acoustic echo cancellation (AEC), acoustic echo suppression (AES) and line echo
cancellation (LEC).
The echo cancellation filter EC10 can output an echo canceled audio signal, which is summed
with the reference audio signal SX10 before being input to the ANC filter F105.
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25
[0082]
[0092]
EC filter EC 10 may be controlled in some embodiments via configuration data specified by limit
control block CB34.
For example, limit control block CB34 may turn the echo cancellation filter on or off based on
one or more of audio signals SE10, SO10 and SY10 or an analysis thereof.
When turned off, the EC filter 10 can, as an example, pass the reproduced audio signal SP10 for
addition before the ANC filter F105.
In another example, when the EC filter EC10 is turned off, the EC filter EC10 can not pass the
reproduced speech signal SP10, but can instead output a null signal. In another example, limit
control block CB34 may provide configuration data for configuring EC filter EC10 to limit or
attenuate the application of EC filter EC10 to reproduced speech signal SP10, which
configuration is , One or more of the speech signals SE10, SO10 and SY10 or an analysis thereof.
[0083]
[0093]
FIG. 6C is a block diagram that illustrates an ANC apparatus A64 that implements an adaptive
ANC (AANC) that can be limited or adjusted according to various aspects of the techniques
described in this disclosure. ANC device A62 may be substantially similar to ANC device A62, but
ANC device A64 adds error speech signal SE10 with the output of EC filter EC10. As described
above, the EC filter EC10 can perform echo cancellation filtering on the reproduced audio signal
SP10. The echo cancellation filter EC10 can perform any form of echo cancellation, including one
or more of acoustic echo cancellation (AEC), acoustic echo suppression (AES) and line echo
cancellation (LEC). The echo cancellation filter EC10 can output an echo canceled voice signal,
which is summed with the error voice signal SE10 before being input to the ANC filter F105.
[0084]
[0094]
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26
An ANC limiting technique can thus be implemented for ANCs that also incorporate echo
cancellation filters, eg EC filter EC10. In other words, ANC devices A 62 and A 64 represent
devices configured to perform echo cancellation on the audio signal to obtain an echo canceled
audio signal, and active noise cancellation on at least a portion of the echo canceled audio signal.
Can be applied.
[0085]
[0095]
FIG. 7 is a block diagram illustrating another variant of limit control block CB34 which performs
noise estimation, inter alia, on error speech signal SE10. The limit control block CB34 shown in
the example of FIG. 7 can be substantially similar to the limit control block CB34 shown in the
example of FIG. 5, but the noise estimation block 36 is preferably capable of the audio signal
SX10, An error audio signal SE10 is received in addition to one or more of SV10 and SO10. This
variant of the noise estimation block 36 can be represented as "noise estimation block 36 '". The
noise estimation block 36 'may, in some instances, calculate the noise level NL42 estimated
based on the error speech signal SE10. Both the noise comparison block 38 and the gain
determination block 40 can operate with substantially the same method as described above for
the limit control block CB34 shown in the example of FIG.
[0086]
[0096] In addition to the various aspects of the technique described above with respect to the
limit controller block CB34 of ANC device A50, the technique estimates when the limit controller
block CB34 of ANC device A60 dynamically adjusts the application of active noise cancellation.
Dynamically adjust the application of adaptive active noise cancellation to at least a portion of
the audio signal to obtain at least a portion of the active noise canceled version of the audio
signal based on the determined noise level Can.
[0087]
[0097] In these and other examples, limit controller block CB34 performs noise estimation as a
function of at least a portion of the reference noise audio signal obtained using the reference
microphone and at least a portion of the error audio signal when performing noise estimation. At
least a portion of the error audio signal is calculated as the difference between at least a portion
of the noise audio signal obtained using the error microphone and at least a portion of the active
noise canceled version of the audio signal.
16-04-2019
27
[0088]
[0098]
8A-8C are block diagrams illustrating example ANC devices A70-76 that implement ANCs that
can be limited or adjusted according to various aspects of the techniques described in this
disclosure.
The ANC device A70 shown in the example of FIG. 8A can be substantially similar to the ANC
device A50, but the noise estimation block 36 is separate from the limit control block CB 34 (this
limit control block is a limit Control block CB34 ').
In some instances, noise estimation block 36 may not be included in ANC device A 70, but may
be included in different blocks, units, modules, devices or devices. The noise estimation block 36
can determine the noise level NL42 estimated by the method described above, and outputs this
estimated noise level NL42 to the limit control block CB34 ', which is shown in FIG. The limit
control block CB 34 ′ may not perform noise estimation, although it may operate substantially
similar to the limit control block CB 34 described above for the 4 and 5 examples.
[0089]
[0099]
FIG. 8B is a block diagram illustrating an example ANC apparatus A72 that implements ANC that
can be limited or adjusted according to various aspects of the techniques described in this
disclosure. The example ANC device A72 may be substantially similar to the ANC device A70, but
the ANC device A72 does not include the noise estimation block 36. In the example of FIG. 8B,
another device, device or unit (possibly in the same device as ANC device A 72) may include a
noise estimation block 36, which provides the noise estimation. In order to do so, the operations
described in more detail can be performed.
[0090]
[0100]
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28
FIG. 8C is a block diagram illustrating an example ANC apparatus A74 that implements ANC that
can be limited or adjusted according to various aspects of the techniques described in this
disclosure. The example ANC device A74 can be substantially similar to the ANC device A70, but
the ANC device A74 includes an additional echo cancellation (EC) filter EC10. The EC filter EC10
can perform echo cancellation filtering on the reproduced audio signal SP10. The echo
cancellation filter EC10 can perform any form of echo cancellation, including one or more of
acoustic echo cancellation (AEC), acoustic echo suppression (AES) and line echo cancellation
(LEC). The echo cancellation filter EC10 can output an echo canceled audio signal, which is
summed with the reference audio signal SX10 before being input to the ANC filter F105. In this
regard, the ANC device A 74 may be representative of a device configured to perform echo
cancellation on an audio signal to obtain an echo canceled audio signal, active on at least a
portion of the echo canceled audio signal. Noise cancellation can be applied.
[0091]
[0101]
FIG. 9 is a schematic diagram illustrating the limit control block CB34 'of the example of FIG. 7 in
more detail. Limit control block CB 34 ′ is substantially similar to limit control block CB 34 ′
shown in the example of FIG. 5, but limit control block CB 34 ′ does not include noise
estimation block 36. Instead, the noise comparison block 38 of the limit control block CB34
'operates in the manner described above to receive the estimated noise level NL42 and output
one or more of the flags FL44 to the gain determination block 40. . Gain determination block 40
also operates in substantially the same manner as described above with respect to FIG. 5 to
output filter coefficients FC 46 that effectively adjust the application of ANC filter F 105 to
reference speech signal SX 10.
[0092]
[0102]
FIG. 10 is a block diagram illustrating an example ANC apparatus A80 implementing ANC that
can be limited or adjusted according to various aspects of the techniques described in this
disclosure. The ANC device A80 can be substantially similar to the ANC device A60, but the noise
estimation block 36 is separate from the limit control block CB34 (this limit control block is
represented as a limit control block CB34 ′ ′ ). In some instances, noise estimation block 36
may not be included in ANC device A 80, but may be included in different blocks, units, modules,
devices or devices. The noise estimation block 36 can determine the noise level NL42 estimated
in the manner described above and output this estimated noise level NL42 to the limit control
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29
block CB34 ′ ′, which is shown in FIG. The limit control block CB34 ′ ′ does not perform
noise estimation, although it can operate substantially similar to the limit control block CB34
described above for the 6 and 7 examples.
[0093]
[0103]
FIG. 11 is a schematic diagram illustrating the limit control block CB34 '' of the example of FIG. 9
in more detail. Limit control block CB 34 ′ ′ is substantially similar to limit control block CB
34 shown in the example of FIG. 7, but limit control block CB 34 ′ ′ does not include noise
estimation block 36. Instead, the noise comparison block 38 of the limit control block CB34 ′ ′
operates in the manner described above to receive the estimated noise level NL 42 and output
one or more of the flags FL 44 to the gain determination block 40. . Gain determination block 40
also operates in substantially the same manner as described above with respect to FIG. 7 to
output filter coefficients FC 46 that effectively adjust the application of ANC filter F 105 to
reference speech signal SX 10.
[0094]
[0104]
FIG. 12 is a flow chart illustrating the exemplary operation of an ANC device configured to
implement various aspects of the techniques described in this disclosure, eg, ANC device A 50
shown in the example of FIG. . First, the limit control block CB34 of the ANC device A50 is a
reference noise audio signal SX10 obtained via a reference microphone, a voice signal AV10 for
voice obtained via a voice microphone (which may differ from the reference microphone), Active
noise canceled version of reference audio signal SX10 (can be called "active noise canceled audio
signal SY10") and mixed output audio signal SO10 (active noise canceled audio signal with
reproduced audio signal SP10 The resulting mixed audio signal may be represented) received,
retrieved or otherwise obtained (100).
[0095]
[0105]
The limit control block CB34 receives these signals SX10, SV10, SY10 and SO10 and initially
carries out a noise estimate on one or more of the signals SX10, SV10, SY10 and SO10 to
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determine the estimated noise level. It can be done (102). Limit control block CB34 may use
signals such as average amplitude, peak amplitude, average power, or any combination thereof,
for a period of time (eg, typically a multiple of the speech frame duration) for signals SX10,
SV10, SY10. And loudness of one or more of SO 10 can be measured. Limit control block CB 34
may then compare the estimated noise level to one or more threshold levels (104).
[0096]
[0106]
When the estimated noise level is above the threshold (or in some implementations above or
above the threshold) ("Yes" 106), the limit control block C34 sends the reference speech signal
SX10 The application of the ANC filter F105 can be adjusted dynamically. In other words, limit
control block CB34 may dynamically adjust the application of active noise cancellation to audio
signal SX10 based on the estimated noise level (108). Limit controller block CB34 performs this
dynamic adjustment by adjusting the gain of ANC filter F105 (eg, by specifying a new filter
coefficient for ANC filter F105 that results in lower gain for ANC filter F105). It can be
performed. When the estimated noise level does not exceed the threshold ("No" 106), the limit
control block CB34 continues to obtain an audio signal, perform noise estimation and compare
the estimated noise level to the threshold. (100 to 106).
[0097]
[0107] The above techniques may, in this regard, enable an apparatus having means (eg, one or
more processors and / or memories) to perform the operations set forth in the following items.
[0098]
[0108]
Item 1
A device for storing an audio signal, and activating at least a portion of the audio signal to obtain
at least a portion of an active noise canceled version of the audio signal when the estimated noise
level is increased. Means for dynamically reducing the application of noise cancellation.
[0099]
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31
[0109]
Item 2 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation comprises at least a portion of the active noise canceled version of the
audio signal when the estimated noise level rises. Means are provided for dynamically reducing
the application of non-adaptive active noise cancellation to at least a portion of the audio signal
to obtain.
[0100]
[0110]
Item 3 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation comprises at least a portion of the active noise canceled version of the
audio signal when the estimated noise level rises. Means are provided for dynamically reducing
the application of active noise cancellation to at least a portion of the audio signal to obtain.
[0101]
[0111]
Item 4 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation is at least a portion of the audio signal based on the estimated noise
level when the estimated noise level is increased. Means for dynamically reducing the gain of
[0102]
[0112]
Item 5 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation is at least a portion of the audio signal based on the estimated noise
level when the estimated noise level is increased. And means for dynamically setting the gain of.
[0103]
[0113]
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Item 6. The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation is active noise cancellation of at least a portion of the reference noise
audio signal when the estimated noise level is increased. Means are provided for dynamically
reducing the gain of the active noise cancellation filter to be applied to at least a portion of the
audio signal to output a version.
[0104]
[0114]
Item 7 The apparatus of item 1, wherein the means for dynamically reducing the application of
active noise cancellation is active noise cancellation of the reference noise speech signal when
the estimated noise level rises above the threshold level. Means for dynamically reducing the
gain of the active noise cancellation filter to be applied to at least a portion of the audio signal to
output at least a portion of the version.
[0105]
[0115]
Item 8 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation comprises at least a portion of an active noise canceled version of the
speech signal based on a mathematical function of the estimated noise level. Means for
dynamically reducing the gain of the active noise cancellation filter to be applied to at least a
portion of the audio signal to output.
[0106]
[0116]
Item 9 The apparatus of item 1, wherein the means for dynamically reducing the application of
active noise cancellation is equal to the gain determined using the estimated noise level as a key
into the look-up table Means for dynamically reducing the gain of the active noise cancellation
filter, the active noise cancellation filter being applied to at least a portion of the audio signal to
output at least a portion of the active noise canceled version of the audio signal Ru.
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[0107]
[0117]
Item 10 The apparatus of claim 1, wherein the means for dynamically reducing the application of
active noise cancellation outputs at least a portion of the active noise canceled version of the
audio signal based on the estimated noise level. Means for dynamically setting the gain of the
active noise cancellation filter to zero prior to applying the active noise cancellation filter to at
least a portion of the audio signal.
[0108]
[0118]
Item 11. The apparatus of claim 1, wherein the means for dynamically reducing the application
of active noise cancellation comprises: means for comparing the estimated noise level to the
threshold level; and the estimated noise level at the threshold Means for dynamically adjusting
the gain of the active noise cancellation filter to be applied to at least a portion of the audio
signal to output at least a portion of the active noise canceled version of the audio signal when
above the level; Equipped with
[0109]
[0119]
Item 12 The apparatus of item 1, wherein the means for dynamically reducing the application of
active noise cancellation is an active noise canceled version of the speech signal when the
estimated noise level is greater than or equal to the threshold level. Dynamically reduce the gain
of at least the active noise cancellation filter to be applied to the first part of the audio signal to
output the first part, set the counter to a value greater than 1 and set the value of the counter A
means for reducing by 1, a means for determining whether the recently updated estimated noise
level exceeds the threshold level when the value of the counter is equal to zero, and the recently
updated estimated noise level has a threshold value The second part of the active noise canceled
version of the speech signal when Means for dynamically reducing the gain of the active noise
cancellation filter to be applied to the second part of the audio signal for output, resetting the
counter to a value greater than 1 and reducing the value of the counter by 1 And.
[0110]
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34
[0120]
Item 13. The apparatus of item 1, wherein the means for dynamically reducing the application of
active noise cancellation is an active noise canceled version of the speech signal when the
estimated noise level is greater than or equal to the threshold level. Dynamically reduce the gain
of the active noise cancellation filter to be applied to at least the first part of the audio signal to
output the first part, reset the counter to a value greater than 1 and reset the value of the
counter Means for reducing by one, and wherein the device is for determining whether the
recently updated estimated noise level exceeds the threshold level when the value of the counter
equals zero, and Active noise when the recently updated estimated noise level is less than the
threshold level. Further comprising means for resetting the said gain in said gain value of the
resulting used before to dynamically adjust the gain of the cancellation filter.
[0111]
[0121]
Item 14 The apparatus of claim 1, further comprising means for enabling dynamic reduction of
at least a portion of the audio signal when the estimated noise level is greater than or equal to
the first threshold level, where: active noise The means for dynamically reducing the application
of the cancellation may include the audio signal to output at least a portion of the active noise
canceled version of the audio signal when the estimated noise level is greater than or equal to the
second threshold level. Means for dynamically reducing the gain of the active noise cancellation
filter to be applied to at least a portion of
[0112]
[0122]
Item 15. The apparatus of claim 1, further comprising means for performing noise estimation on
the reference noise audio signal to obtain an estimated noise level.
[0113]
[0123]
Item 16 15. The apparatus of claim 15, wherein the means for performing noise estimation
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comprises means for determining the estimated noise level as an average amplitude, peak
amplitude, or average power of at least a portion of the reference noise audio signal.
[0114]
[0124]
Item 17. 15. The apparatus of claim 15, wherein the means for performing noise estimation
comprises: means for performing non-wind noise estimation on the reference noise audio signal
to obtain a first estimated noise level; and the estimated noise level Means for determining as a
function of the first estimated noise level and the second estimated noise level.
[0115]
[0125]
Item 18 The apparatus of item 1, means for performing echo cancellation on the audio signal to
obtain an echo canceled audio signal, and means for applying active noise cancellation to at least
a portion of the echo canceled audio signal, Further comprising
[0116]
[0126] The above techniques, when implemented, apply active noise cancellation to at least a
portion of the audio signal to obtain at least a portion of the active noise canceled version of the
audio signal when the estimated noise level rises. A non-transitory computer readable storage
medium having instructions stored thereon that cause one or more processors to perform a
dynamic reduction may also be enabled.
[0117]
[0127]
In one or more examples, the functions described may be implemented in hardware, software,
firmware, or any combination thereof.
When implemented in software, the functions may be stored or transmitted as one or more
instructions or code on a computer readable medium and may be performed by a processing unit
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based on hardware. A computer readable storage medium may comprise a computer readable
storage medium, the computer readable storage medium being a tangible medium, such as a data
storage medium, or a computer program, for example from one location to another by means of a
communication protocol. Corresponding to the communication medium including the medium
that facilitates the transfer of the As such, the computer readable medium can generally
correspond to (1) a tangible computer readable storage medium that is non-transitory or (2) a
communication medium such as a signal or carrier wave. A data carrier may be any available
access by one or more computers or one or more processors to retrieve instructions, code and /
or data structures for implementation of the techniques described in this disclosure. It can be a
medium.
[0118]
[0128]
By way of example and not limitation, such computer readable storage medium may be RAM,
ROM, EEPROM®, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic
storage. The apparatus, flash memory, or other medium that can be used to store the desired
program code in the form of instructions or data structures and can be accessed by a computer
can be provided. Further, any connection is properly termed a computer-readable medium. For
example, the instructions may use a coaxial cable, fiber optic cable, twisted pair, digital
subscriber line (DSL), or a wireless technology such as infrared, wireless, and microwave to make
a website, server or other remote When transmitted from a source, the coaxial cable, fiber optic
cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are
included in the definition of medium. However, it is understood that computer readable storage
media and data storage media do not include connections, carriers, signals or other temporary
media, but instead are directed to non-transitory, tangible storage media. It should. The discs
(disc and disc) as used herein are compact disc (CD), laser disc (registered trademark) (disc),
optical disc (disc) and digital versatile disc (DVD) (disc) , A floppy (registered trademark) disk,
and a Blu-ray disc (disc), where the disc normally duplicates data magnetically, and the disc
optically couples data using a laser. Duplicate. Combinations of the above should also be included
within the scope of computer readable media.
[0119]
[0129]
The instructions may be one or more processors, such as one or more digital signal processors
(DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field
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programmable logic arrays (FPGAs), or other equivalent integrated circuits. Or can be
implemented by discrete logic circuits. Thus, the term "processor" as used herein can mean any
of the above structures or any other structure suitable for implementation of the techniques
described herein. Further, in some aspects, the functions described herein may be provided
within dedicated hardware and / or software modules configured for encoding and decoding, or
may be incorporated into a combined codec be able to. Further, the techniques may be fully
implemented in one or more circuits or logic elements.
[0120]
[0130]
The techniques of this disclosure may be implemented in a wide variety of devices or
apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (eg, a chip set).
Although this disclosure describes various components, modules, or units to highlight functional
aspects of a device configured to implement the disclosed techniques, implementations with
different hardware units are not necessarily required. do not do. Rather, as described above, the
various units may be associated within the codec hardware unit in association with appropriate
software and / or firmware, or interoperable including one or more processors as described
above Can be provided by a set of hardware units.
[0121]
Various embodiments of the invention have been described. These and other embodiments are
within the scope of the following claims.
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