Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR NOISE CANCELLATION
IN EMERGENCY RESPONSE VEHICLES
TECHNICAL FIELD
[0001] This application relates to a system and method for noise cancellation
in emergency
response vehicles.
BACKGROUND
[0002] Sirens attached to emergency vehicles are used to inform neighboring
vehicles an
emergency situation. However, the long-term exposure of first responders to
loud noise
generated from the sirens may cause many severe medical issues such as
deafness.
[0003] Thus, there is a need for a method and system to reduce the siren noise
of emergency
vehicles.
SUMMARY OF THE INVENTION
[0004] The objective of the present disclosure is to provide a system and
method for effectively
reducing or cancelling out a noise generated from the siren in an emergency
vehicle. Aspects of
the present disclosure are a system, method and storage medium for reducing or
cancelling out a
noise in an emergency vehicle.
[0005] In one aspect, there is provided a system for noise cancellation in a
vehicle. The system
includes a controller and a sound generator.
[0006] The controller is configured to determine a waveform of a first sound
wave at a first
location. The first sound wave is a noise sound generated from a noise source
such as a siren
attached to the vehicle. Based on the waveform of the first sound wave at the
first location and
a first distance between the first location and the second location, the
controller is configured to
calculate another waveform of the first sound wave which will arrive a second
location where an
operator is located. Further, the controller is configured to generate at
least one control signal
based on the determined another waveform of the first sound wave at the second
location.
[0007] The at least one sound generator is positioned at a third location and
is configured to
generate a second sound wave based on the at least one control signal. The
second sound wave,
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when being super-positioned with the first sound wave, acts to cancel out the
first sound wave at
the second location. To this end, at the second location, the amplitude and
the frequency of the
second sound wave are substantially the same as the amplitude and the
frequency of the first
sound wave, respectively, and the phase of the second sound wave is opposite
to the first sound
wave. For example, the sound generator is embodied with a speaker.
[0008] In one embodiment, the first location is where the noise source is
located or in vicinity of
the noise source. The waveform of the first sound wave at the first location
(i.e., location of the
noise source) are known to the system and are stored in memory. Thus, the
controller is
configured to read the information of the waveform of the first sound wave at
the first location to
determine the waveform of the first sound wave at the first location.
[0009] In one embodiment, the noise cancellation system further includes at
least one sound
receiver configured to detect the first sound wave at the first location as
well as other measured
locations throughout the vehicle and transmit the detected first sound wave to
the controller. For
example, the sound receiver is embodied with a microphone.
[0010] In order to cancel out the first sound wave at the second location, the
waveform of the
second sound wave generated from the sound generator is adapted in a manner to
cancel out the
first sound wave at the second location.
[0011] In one embodiment, the first sound wave can be a noise that should be
reduced or
cancelled out that is generated by the noise source.
[0012] In one embodiment, the noise source is positioned outside the vehicle
(e.g., on top of the
vehicle's roof), and the noise source is positioned at the first location
which the controller
determines the waveform of the first sound wave. For example, in this
embodiment, no sound
receiver (e.g., microphone) is needed to detect the first sound wave since the
system has known
the waveform of the first sound wave at the first location generated by the
noise source.
[0013] In one embodiment, the system may include one or more optional sound
receivers to
detect the first sound wave at various locations to make it easier to
determine the waveform of
the first sound wave. In one example, a sound receiver can be positioned at
the location which
the noise source is positioned or in the vicinity of the noise source to
detect the first sound wave
output from the noise source. In another embodiment, the location at which the
noise source is
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positioned at is not the same as the first location at which the controller
determines the waveform
of the first sound wave; for example, the noise source is positioned outside
the vehicle, and the
sound receiver is positioned at the first location inside the vehicle. Thus,
the first sound wave
generated from the noise source positioned outside the vehicle travels to the
second location via
the first location at which the waveform of the first sound wave are
determined by the controller.
[0014] In one embodiment, the first location of the sound detector is
positioned on a direct path
of the first sound wave from the location of the noise source to the second
location.
[0015] In one embodiment, the controller is configured to calculate the
required waveform of the
second sound wave at the third location of the sound generator. The second
sound wave
generated from the sound generator travels along a path from the third
location to the second
location, experiencing changes in at least amplitude, frequency, and/or phase
over the path. The
amount of the changes in amplitude, frequency, and/or phase of the second
sound wave depends
on a distance between the third location and the second location. Given that
at the second
location which the operator is positioned, the second sound wave is required
to have the
waveform to cancel out the first sound wave (as described above), the waveform
of the second
sound wave at the third location can be reversely calculated back from the
target waveform of
the second sound wave at the second location.
[0016] In one embodiment, the noise cancellation system further includes one
or more sensors
configured to scan a layout an interior of the vehicle and transmit
information of the scanned
layout to the controller. The controller is configured to determine the second
location, the third
location, and the fourth location based on the information of the scanned
layout.
[0017] In one embodiment, the controller is configured to determine an angle
at which the first
sound wave generated from the noise source enters into a cabin of the vehicle
through a surface
(e.g., roof surface of the vehicle) and calculate the another waveform of the
first sound wave at
the second location based on the determined angle. For example, the angle is
an angle at which a
direction extending along a direct path between the location of the noise
source and the second
location of the operator crosses the surface of the vehicle which the first
sound wave passes
through.
[0018] In one embodiment, information regarding the angle may be stored in the
memory, so
that the controller reads the information of the angle from the memory.
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[0019] In one embodiment, when the determined angle gets closer to 90 degrees
with respect to
the surface of the vehicle, the amplitude of the first sound wave after
passing through the surface
of the vehicle becomes increased and a frequency of the first sound wave
perceived by the
operator after passing through the surface becomes increased.
[0020] In one embodiment, when the determined angle gets farther away from the
90 degrees
with respect to the surface of the vehicle, the amplitude of the first sound
wave after passing
through the surface of the vehicle becomes decreased and the frequency of the
first sound wave
perceived by the operator after passing through the surface becomes decreased.
[0021] In one embodiment, the frequency of the first sound wave perceived by
the operator after
passing through the surface of the vehicle is determined by a following
equation:
[0022] fperceived = factualCO S (0), wherein f
, perceived is the frequency of the first sound
wave perceived by the operator after passing through the surface, f
, actual is an actual frequency
of the first sound wave before entering the surface, and 0 is the determined
angle.
[0023] In one embodiment, the first sound wave at the second location includes
a directly
transmitted portion and at least one reflected portion. The directly
transmitted portion
corresponds to the first sound wave transmitted directly from the first
location without being
reflected off a surface of the vehicle. The at least one reflected portion
corresponds to the first
sound wave reflected off at least one surface of the vehicle. Thus, the at
least one control signal
generated by the controller includes a first control signal and a second
control signal. A portion
of the second sound wave is generated based on the first control signal to
cancel out the directly
transmitted portion, and another portion of the second sound wave is generated
based on the
second control signal to cancel out the reflected portion.
[0024] In one embodiment, the first control signal is generated based on the
first distance, and
the second control signal is generated based on a distance of the travel path
of the reflected
portion of the second sound wave.
[0025] In another aspect of the present disclosure, there is provided a noise
cancellation method
for a vehicle. The method includes determining, by a controller, a waveform of
a first sound
wave at a first location; calculating, by the controller, another waveform of
the first sound wave
at a second location of an operator based on the waveform of the first sound
wave at the first
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location and a first distance between the first location and the second
location; generating, by the
controller, at least one control signal based on the determined another
waveform of the first
sound wave at the second location; and generating, by a sound generator
positioned at a third
location, a second sound wave based on the at least one control signal.
[0026] In still yet another aspect of the present disclosure, there is
provided a computer-readable
storage medium having computer readable program instructions. The computer
readable
program instructions can be read and executed by at least one processor for
performing a method
for noise cancellation in a vehicle. The method includes determining a
waveform of a first sound
wave at a first location; calculating another waveform of the first sound wave
at a second
location of an operator based on the waveform of the first sound wave at the
first location and a
first distance between the first location and the second location; generating
at least one control
signal based on the determined another waveform of the first sound wave at the
second location;
and generating, using a sound generator positioned at a third location, a
second sound wave
based on the at least one control signal.
[0027] In one embodiment, the waveform of the second sound wave are formed to
cancel out the
first sound wave at the second location, and the first sound wave is generated
by a noise source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The present disclosure will become more readily apparent from the
specific description
accompanied by the drawings.
[0029] FIG. 1 is a block diagram of an example emergency vehicle having a
noise cancellation
system according to an embodiment of the present disclosure;
[0030] FIG. 2 is a view illustrating an example travel path of a sound wave
between a reference
location and a target location according to an embodiment of the present
disclosure;
[0031] FIG. 3A is a view illustrating example travel paths of a noise sound
wave and a
compensation sound wave when a reference location is outside a vehicle
according to an
embodiment of the present disclosure;
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[0032] FIG. 3B is a view illustrating an example channel model of a noise
sound wave in case of
a reference location being outside a vehicle according to an embodiment of the
present
disclosure;
[0033] FIG. 4A is a view illustrating example travel paths of a noise sound
wave and a
compensation sound wave in case of a reference location being inside a vehicle
according to an
embodiment of the present disclosure;
[0034] FIG. 4B is a view illustrating an example channel model of a noise
sound wave in case of
a reference location being inside a vehicle according to an embodiment of the
present disclosure;
[0035] FIG. 5 is a view illustrating an example travel path of a reflected
noise sound wave
according to an embodiment of the present disclosure;
[0036] FIG. 6A is a view illustrating an example channel model of a noise
sound wave in case of
a reference location being outside a vehicle according to an embodiment of the
present
disclosure;
[0037] FIG. 6B is a view illustrating an example channel model of a noise
sound wave in case of
a reference location being inside a vehicle according to an embodiment of the
present disclosure;
[0038] FIG. 7 is a flow chart illustrating a noise cancellation method
according to an
embodiment of the present disclosure;
[0039] FIG. 8 is a block diagram of a computing system according to an
embodiment of the
present disclosure; and
[0040] FIG. 9 is a view illustrating an example neural network with hidden
layers used for
training an artificial intelligence according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0041] The present disclosure may be understood more readily by reference to
the following
detailed description of the disclosure taken in connection with the
accompanying drawing
figures, which form a part of this disclosure. It is to be understood that
this disclosure is not
limited to the specific devices, methods, conditions or parameters described
and/or shown herein,
and that the terminology used herein is for the purpose of describing
particular embodiments by
way of example only and is not intended to be limiting of the claimed
disclosure.
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[0042] Also, as used in the specification and including the appended claims,
the singular forms
"a," "an," and "the" include the plural, and reference to a particular
numerical value includes at
least that particular value, unless the context clearly dictates otherwise.
Ranges may be expressed
herein as from "about" or "approximately" one particular value and/or to
"about" or
"approximately" another particular value. When such a range is expressed,
another embodiment
includes from the one particular value and/or to the other particular value.
[0043] The phrases "at least one", "one or more", and "and/or" are open-ended
expressions that
are both conjunctive and disjunctive in operation. For example, each of the
expressions "at least
one of A, B and C", "at least one of A, B, or C", "one or more of A, B, and
C", "one or more of
A, B, or C" and "A, B, and/or C" means A alone, B alone, C alone, A and B
together, A and C
together, B and C together, or A, B and C together.
[0044] For the sake of description, the present disclosure will be described
with reference to a
case where the noise cancellation system is used for an emergency vehicle as
only an example.
However, embodiments of the present disclosure are not limited thereto. It
will be apparent that
the noise cancellation system can be applied to any other vehicles or any
space where the
waveform of a noise sound wave is estimated.
[0045] FIG. 1 is a block diagram of an example emergency vehicle (EV) 10
having a noise
cancellation system 150 according to an embodiment of the present disclosure.
The noise
cancellation system 150 can be installed to be attached on an emergency
vehicle 10 or in the
vicinity thereof. The noise cancelation system 150 is configured to cancel out
or reduce a noise
(or noise sound wave) generated from a noise source 100 attached to a surface
12 of the vehicle
or in the vicinity thereof. In one embodiment, the noise source 100 can be a
siren and
attached on a top surface 12 of the vehicle 10, as exemplary depicted in FIG.
1. However,
embodiments of the present disclosure are not limited thereto. For example,
the noise source 100
can be an engine or any other elements generating noises.
[0046] Referring now to FIG. 1, the noise cancellation system 150 can include
a control unit 200
and at least one speaker 300 in communication with the control unit 200. As
shown in FIG. 1,
the control unit 200 includes at least one processor 210 (e.g., central
processing unit (CPU)), a
memory 220 coupled to the processor 210, and a communication interface 230.
For example, the
control unit 200 is implemented using an arm cortex m4 microcontroller for the
floating-point
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calculations, which allows increase of the calculation speed and reduce
latency of the
compensation sound wave being outputted from the speaker 300 to match the
phase better. In
some aspects, a real time operating system will also be used to manage the
different tasks
involved in this calculation and manage the required deterministic timing of
the calculations.
[0047] Referring further to FIG. 2, the control unit 200 estimates a waveform
of the noise sound
wave 110 arriving a target location LT. The noise sound wave 110 at the target
location LT is a
wave which has been generated by the noise source 100 and transmitted over a
certain path
between the noise source 100 and the target location LT, experiencing changes
in amplitude,
phase and/or frequency over the path. The control unit 200 generates a control
signal 201 based
on the estimated waveform of the noise sound wave 110 at the target location
LT and transmit the
control signal 201 to the speaker 300. The speaker 300 is configured to
generate a compensation
sound wave 310 based on the control signal 201 and transmit the compensation
sound wave 310
to the target location LT.
[0048] The target location LT is a location at which the system 150 wants to
have the noise
cancelled out. As exemplary depicted in FIG. 1, the target location LT can be
at an operator
(e.g., driver)'s ears or in the vicinity thereof. By way of example only, the
target location LT can
be set on a headrest of the operator's seat.
[0049] At the target location LT, the compensation sound wave 310 has to have
a waveform
which acts to reduce or cancel out the noise sound wave thereat. Referring to
FIG. 1, the
compensation sound wave 310 that has to be generated from the speaker 300 can
be calculated
back based on a target waveform at the target location LT and a distance DS _T
of the speaker 300
positioned at a location Ls away from the target location LT. For example, at
the target location
LT, the target waveform of the compensation sound wave 310 can have
substantially the same
amplitude and frequency as the estimated waveform of the noise sound wave 110,
and the target
waveform of the compensation sound wave 310 has an opposite phase to the
estimated waveform
of the noise sound wave 110 in order for the noise sound wave at the target
location LT to be
cancelled out or reduced.
[0050] The noise sound wave 110 arriving the target location LT may include a
directly
transmitted portion and one or more reflected portions. The directly
transmitted wave
corresponds to the noise sound wave transmitted directly from the noise source
100 to the target
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location LT without being reflected off any internal surface of the vehicle
10, and the reflected
portion(s) correspond(s) to the noise sound wave reflected off at least one
internal surface of the
vehicle 10.
[0051] Here below is described a mechanism for cancelling out the directly
transmitted portion
at the target location LT.
[0052] CANCELLATION OF DIRECTLY TRANSMITTED PORTION OF NOISE SOUND
WAVE
[0053] As described above, the waveform of the noise sound wave 110 arriving
the target
location LT have to be determined in order to allow the speaker 300 to
generate a compensation
sound wave which acts to reduce or cancel out the noise sound wave 110 at the
target location
LT.
[0054] To that end, referring now to FIG. 2, the noise sound wave 110 at the
target location LT
can be calculated back by using a reference waveform of the noise sound wave
110 and a
distance DRF T between a location LRF and the target location LT. The
reference location LRF is a
location where the reference waveform is determined. Further, for the sake of
description, the
reference waveform of the noise sound wave can hereinafter be referred to as a
"reference
waveform".
[0055] In one embodiment, referring to FIG. 3A, the reference waveform may be
a waveform of
the noise sound wave at the location LNS of the noise source 100. In this
case, as the location
LNS is positioned outside the vehicle 10, the noise sound wave 110 may
experience changes in
amplitudes, frequencies and/or phases over a travel path from the location LNS
to the target
location LT, a corresponding channel model of which is as conceptually
depicted in FIG. 3B.
[0056] Referring now to FIG. 3B, a channel element 1310 is taken into account
for a loss which
the noise sound wave 110 undergoes when passing through a surface 12. A
channel element
1320 is taken into account for a frequency change due to an angle 0 at which
the noise sound
wave 110 enters into the cabin of the vehicle 10 through the surface 12.
Channel elements 1330
and 1340 are taken into account for a loss and a phase change, respectively,
during the noise
sound wave traveling over a path with a distance (e.g., D12 T). The loss of
energy in a sound
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wave through a surface is due primarily to the reflection of said sound wave
when crossing
between materials of varying acoustic impedances.
[0057] For example, a percentage R of energy reflected back can be calculated
by the following
Equation (1):
[0058] R = (¨
42-E-Z1)2
X 100 ----------------------------------- Equation (1)
Z2 Z1
[0059] Here, Zi and Z2 are impedances of the mediums that the sound waves are
traveling
through. For example, Zi represents an impedance of air, and Z2 represents an
impedance of a
surface (e.g., door) of the vehicle 10 that the sound wave will have to pass
through in order to
enter the cabin. The equation (1) is called Fresnel's equation.
[0060] In the case of air and steel, which a car door is primarily comprised
of, this reflection
accounts for greater than 99 percent of the sound energy being reflected back
to the source
instead of being transmitted into the cabin. This varies from material to
material 12 which may
be made of e.g., metal. The entering angle 0 of the noise sound wave may be
measured by using
locations of the noise source 100, an operator (e.g., target location LT), the
surface 12 of the
vehicle 10, etc. When the angle 0 gets closer to 90 degrees with respect to
the surface 12 of the
vehicle, the amplitude of the noise sound wave after passing through the
surface 12 will become
increased. In addition, when the angle 0 gets farther from 90 degrees with
respect to the surface
12 of the vehicle, the amplitude of the noise sound wave after passing through
the surface 12 will
become decreased.
[0061] Stokes's law of sound attenuation is A(d) = Ape-ad where d is a
distance in meters A0 is
the initial amplitude of the sound and a is the attenuation of sound in that
material.
[0062] In this example channel model of FIG. 3B, frequency phase shift, and a
difference of
attenuation of the sound wave through the surface of the vehicle 12 are
neglected for the sake of
simplicity.
[0063] The phase that the sound wave is currently in can then be calculated
using t = x/v
where t is equal to the time it takes a waveform to travel a distance x moving
at a velocity v of
the speed of sound 343m/s.
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[0064] Once t is known, SNs = A(d)cos(wNst ¨ (PNs) can be used to find the
actual amplitude
of the sound wave SNsat a point with attenuation being accounted for.
[0065] Here ANs is an amplitude, wNs is an angular frequency, and cpNs is the
measured or
known output phase.
[0066] Then, the waveform ST of the noise sound wave arriving the target
location LT will be
given as:
[0067] Referring again to FIG. 3B, the amplitude AT at the target location LT
will be given by
af3ANs, here a and f3 are losses corresponding to the channel elements 1310
and 1330,
respectively. The frequency WT at the target location LT will be given by
wNscos61. The phase
(PT at the target location LT will be given by cpNs + kD12 T, here k is a wave
number. The wave
number is given by Xis, here X, is a wavelength and s is a speed of a sound
wave (e.g., 340
meters/second). Thus, co, T T =(.1)Ns + X,D12 T/S, here A = slf.
[0068] Referring back to FIG. 3A, in order to cancel out the directly
transmitted portion of the
noise sound wave 110, the compensation sound wave 310 at the target location
LT has to be
given by:
[0069] Sc = Accos(wct ¨ Pc) --- Equation (2)
[0070] Here, at the location LT, the amplitude Ac and the frequency wc of the
compensation
sound wave 310 are substantially the same as those (AT and WT) of the noise
sound wave 110,
and the phase (pc of the compensation sound wave 310 is opposite to the phase
(PT of the noise
sound wave 110 (e.g., (pc = ¨PT). As described above, the control unit 200
calculates the
compensation sound wave 310 that has to be generated from the speaker 300
based on the target
waveform and a distance Dsi T of the speaker 300 away from the target location
LT, generates
the control signal 201 based on the calculation, and transmits the control
signal 201 to the
speaker 300.
[0071] In one embodiment, the reference waveform of the noise sound wave at
the location LNS
(e.g., reference location) may be known to the system 150. For example,
information of the
noise sound waveform regarding amplitude, frequency and phase at the location
LNS are stored in
the memory 220 of the control unit 200. The control unit 200 may read such
information of the
reference waveform at the location LNS from the memory 220 and calculate the
waveform
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change of the noise sound wave 110 over the path from the noise source 100 to
the target
location LT, e.g., based on the channel model shown in FIG. 3B.
[0072] In one embodiment, the reference waveform of the noise sound wave at
the location LNS
can be measured by using at least one microphone. In one example, one or more
microphones
can be attached to the noise source 100, or positioned around the location LNS
of the noise source
100. The measured reference waveform of the noise sound wave may be
transmitted to the
control unit 200 via the communication interfaces 230. The control unit 200
may have a sound
analyzing module 240 for determining the characteristics (e.g., amplitude,
frequency, and phase)
of the noise sound wave transmitted from the microphone(s).
[0073] In one embodiment, referring to FIG. 4A, the reference waveform can be
a waveform at
a location positioned inside the vehicle 10. For example, the reference
waveform is measured by
using at least one microphone positioned at a location Lmi inside the vehicle
10. The
microphone can be positioned in a direct path 122 from the noise source 100 to
the target
location LT.
[0074] Depicted in FIG. 4B is an example channel model from the location Lmi
to the target
location LT. Referring to FIG. 4B, channel elements 1410 and 1420 are taken
into account for a
loss and a phase change, respectively, during the noise sound wave traveling
over a path from the
location Lmi to the target location LT having a distance Dml T. As the
microphone is positioned
inside the vehicle 10, no consideration is made with regard to loss and
frequency shift through
the surface 12 which correspond to the channel elements 1310 and 1320,
respectively.
[0075] Referring back to FIG. 1, the noise cancellation system 150 may further
include at least
one space scanner such as a time of flight sensor, sonar module, or camera's
tracking for facial
features located at specific positions to measure a layout of the interior of
the vehicle and the
position of the drivers ears10 which allows the system 150 to be aware of
positions of the
microphone(s) (e.g., 400), the speaker 300, the target location LT, the
surfaces (e.g., 12 and 14),
etc. The measured layout information of the interior of the vehicle 10 may be
transmitted to the
control unit 200 and/or stored in the memory 220.
[0076] CANCELLATION OF REFLECTED PORTION OF NOISE SOUND WAVE (OPTIONAL)
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[0077] The noise sound wave 110 may travel over different paths than the
direct path 122 toward
the target location LT, being reflected off one or more internal surfaces of
the vehicle. Since the
cabin of a vehicle is typically less than tens of meters (e.g., less than 17
meters) long, the
reflections of the noise sound wave off cabin's internal surface(s) may create
a perceived
lengthening of tones to the operator instead of an echo. The waveform of the
reflected noise
sound wave at the target location LT can be estimated by taking into account
the paths over
which the noise sound wave has to travel to reach the target location LT.
[0078] The speaker 300 or at least one another speaker (not shown) may be used
to generate a
compensation sound wave to cancel out the estimated waveform of the reflected
noise sound
wave, as described above. Duplicate description will be omitted for the sake
of simplicity.
[0079] For the sake of explanation only, let us consider an example reflection
path 123 which the
noise sound wave will travel over, as shown in FIG. 5. The noise sound wave
generated by the
noise source 100 will pass through the surface 12, travels over an air path
from the surface 12 to
the surface 14, reflect off the surface 14, and travels over another air path
from the surface 14 to
the target location LT.
[0080] Depending on a location of the reference waveform of the noise sound
wave 110, a
channel model that has to be considered may vary. For example, if the
reference location of the
reference waveform is where the noise source 100 is positioned or near the
noise source 100, the
channel model may have to consider at least a loss through the surface 12 (see
e.g., 1610 of FIG
6A), a frequency shift through the surface 12 (see e.g., 1620 of FIG 6A), a
loss through the air
path D12 14 between the surface 12 and the surface 14 (see e.g., 1630 of FIG
6A), a phase shift
through the air path D12 14 (see e.g., 1640 of FIG 6A), an effect of
reflection off the surface 14
(see e.g., 1650 of FIG 6A), a loss through the air path D14 _T between the
surface 14 and the target
location LT (see e.g., 1660 of FIG 6A) , and a phase shift through the air
path D14 _T (see e.g.,
1670 of FIG 6A). In order to consider the effect of the reflection off the
surface 14, an angle at
which the sound wave is reflected off the surface 14 and a material which the
surface 14 is made
of can be considered to determine the waveform change in e.g., amplitude,
frequency and phase.
[0081] In addition, if the reference location of the reference waveform is
where a microphone is
positioned, as depicted in an example embodiment of FIG. 5 (for example, the
microphone is
positioned at a location Lm2 on a travel path between the last reflection
surface 14 and the target
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location LT), the channel model may only consider the loss through the air
path D14 _T between
the surface 14 and the target location LT (see e.g., 1680 of FIG 6B) and the
phase shift through
the air path D14 _T (see e.g., 1690 of FIG 6B), as depicted in FIG. 6B.
[0082] Practically, due to large numbers of surfaces in the vehicle cabin
between a noise source
100 and the target location LT, there may be a lot of different reflection
paths of the noise sound
wave other than the example path 123 of FIG. 5, which may cause the
calculation for the
resultant waveform of the noise sound wave at the target location LT to be
harder. For example,
this can be addressed by testing different kinds of vehicles with different
placements of
microphones and/or different frequencies of the noise sound wave so as to find
out dominant
reflection paths of the noise sound wave and optimal locations of microphones
to calculate the
waveform of the noise sound wave at the target location LT.
[0083] As described above, the noise cancellation system 150 can use at least
one space scanner
500 such as a time of flight sensor or sonar module to map out a layout of the
interior of the
vehicle 10 which allows the system 150 to be aware of positions of the
microphones (e.g., 400),
the speaker 300, the target location LT, the surface (e.g., 12 and 14), etc.
The measured
information of the interior of the vehicle 10 can be used to estimate
distances among the
locations at interest or amount of time which it will take for the reflected
sound to reach the
target location LT.
[0084] In one embodiment, in order to reduce these reflections of the noise
sound wave off the
surfaces as well as the leakage of noise sound wave into the vehicle cabin,
one or more internal
surfaces (e.g., 12 and 14) of the vehicle 10 can be made of a sound absorbing
or dampening
material such as porous material which is outfitted in the vehicle. The use of
the sound absorbing
or dampening material for the internal surfaces of the vehicle may make the
estimation of the
waveform of noise sound at the target location more predictable.
[0085] In one embodiment, the at least one speaker 300 can be provided as a
stand-alone, or a
part of the OEM sound system built in the vehicle. The speaker(s) can have the
ability to outfit
the vehicle interior with a noise absorbing material to reduce the reflections
of the wave off
itself.
[0086] In some aspects, the waveform of the noise sound wave 110 arriving the
target location
LT can be determined by leveraging an artificial intelligence (Al) platform
based on machine
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learning algorithms. For example, instead of calculating the waveform of the
noise sound wave
at the target location, an AI-powered platform for testing different vehicle
types with different
placements of speakers and a range of frequencies outputted by the noise
source can be used, so
that various parameters of the Al platform such as weights of the equations
between the nodes in
a neural network can be trained so as to reduce the measured volume at a known
distance from
the noise source by a greatest amount throughout a range of frequencies.
[0087] An example of a neural network with hidden layers used for training the
Al platform is
depicted in FIG. 9. For example, electronics (e.g., Omron Electronics B5T-
007001-020) of a
camera can be used to detect a person's face as well as its pitch. In
combination with a second
camera at a known distance and angle from the first this can be used to
triangulate the position of
the driver and each of their ears. This is one variable that can be plugged
into the input layer 910
of the neural network of FIG. 9 along with the frequency amplitude phase and
distance from the
noise source as well as the vehicle the air is being trained on itself. The
output layer 930 would
then consist of only one output which is the decibel level within a narrow
frequency around the
outputted frequency of the siren at that time at the drivers ears which can be
measured using a
microphone. The hidden layer 920 of the Al then will vary the weights of the
equations
contained within it to minimize the decibel level within this narrow frequency
band.
[0088] In some aspects, at least one microphone (not shown) can be placed
around the vehicle 10
for measuring ambient noise. The ambient noise can be amplified and provided
to the control
unit 200. The information of the ambient noise can be used by the control unit
200 to allow the
operator (e.g., police officer) monitor the surroundings of the vehicle or
patrol for someone on
foot.
[0089] FIG. 7 is a flow chart illustrating a noise cancellation method
according to an
embodiment of the present disclosure.
[0090] Referring now to FIG. 7, the method commences with step S710 of the
control unit 200
determines the reference waveform of the noise sound wave 100 at a reference
location LRF.
[0091] In step S720, the control unit calculates a waveform of the noise sound
wave at the target
location based on the determined reference waveform and a distance between the
reference
location and the target location.
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[0092] In step S730, the control unit generates the control signal 201 based
on the waveform of
the noise sound wave at the target location to transmit the control signal to
at least one speaker
300.
[0093] In step S740, the speaker 300 generates the compensation sound wave
based on the
control signal to transmit the compensation sound wave to the target location.
[0094] FIG. 8 is a block diagram of a computing system 4000 according to an
exemplary
embodiment of the present disclosure.
[0095] Referring to FIG. 8, the computing system 4000 may be used as a
platform for
performing: the functions or operations described hereinabove with respect to
at least one of the
noise cancellation system 150 of FIG. 1 and/or the method described with
reference to FIG. 7.
[0096] Referring to FIG. 8, the computing system 4000 may include a processor
4010, I/0
devices 4020, a memory system 4030, a display device 4040, and/or a network
adaptor 4050.
[0097] The processor 4010 may drive the I/0 devices 4020, the memory system
4030, the
display device 4040, and/or the network adaptor 4050 through a bus 4060.
[0098] The computing system 4000 may include a program module for performing:
the functions
or operations described hereinabove with respect to at least one of the noise
cancellation system
150 of FIG. 1 and/or the method described with reference to FIG. 7. For
example, the program
module may include routines, programs, objects, components, logic, data
structures, or the like,
for performing particular tasks or implement particular abstract data types.
The processor (e.g.,
4010) of the computing system 4000 may execute instructions written in the
program module to
perform: the functions or operations described hereinabove with respect to at
least one of the
noise cancellation system 150 of FIG. 1 and/or the method described with
reference to FIG. 7.
The program module may be programmed into the integrated circuits of the
processor (e.g.,
4010). In an exemplary embodiment, the program module may be stored in the
memory system
(e.g., 4030) or in a remote computer system storage media.
[0099] The computing system 4000 may include a variety of computing system
readable media.
Such media may be any available media that is accessible by the computer
system (e.g., 4000),
and it may include both volatile and non-volatile media, removable and non-
removable media.
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[0100] The memory system (e.g., 4030) can include computer system readable
media in the form
of volatile memory, such as RAM and/or cache memory or others. The computer
system (e.g.,
4000) may further include other removable/non-removable, volatile/non-volatile
computer
system storage media.
[0101] The computer system (e.g., 4000) may communicate with one or more
devices using the
network adapter (e.g., 4050). The network adapter may support wired
communications based on
Internet, local area network (LAN), wide area network (WAN), or the like, or
wireless
communications based on code division multiple access (CDMA), global system
for mobile
communication (GSM), wideband CDMA, CDMA-2000, time division multiple access
(TDMA), long term evolution (LTE), wireless LAN, Bluetooth, Zig Bee, or the
like.
[0102] Exemplary embodiments of the present disclosure may include a system, a
method,
and/or a non-transitory computer readable storage medium. The non-transitory
computer
readable storage medium (e.g., the memory system 4030) has computer readable
program
instructions thereon for causing a processor to carry out aspects of the
present disclosure.
[0103] The computer readable storage medium can be a tangible device that can
retain and store
instructions for use by an instruction execution device. The computer readable
storage medium
may be, for example, but not limited to, an electronic storage device, a
magnetic storage device,
an optical storage device, an electromagnetic storage device, a semiconductor
storage device, or
any suitable combination of the foregoing. A non-exhaustive list of more
specific examples of
the computer readable storage medium includes the following: a portable
computer diskette, a
hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EEPROM or Flash memory), a static random access
memory
(SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile
disk (DVD),
a memory stick, a floppy disk, or the like, a mechanically encoded device such
as punch-cards or
raised structures in a groove having instructions recorded thereon, and any
suitable combination
of the foregoing. A computer readable storage medium, as used herein, is not
to be construed as
being transitory signals per se, such as radio waves or other freely
propagating electromagnetic
waves, electromagnetic waves propagating through a waveguide or other
transmission media
(e.g., light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a
wire.
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[0104] Computer readable program instructions described herein can be
downloaded to the
computing system 4000 from the computer readable storage medium or to an
external computer
or external storage device via a network. The network may include copper
transmission cables,
optical transmission fibers, wireless transmission, routers, firewalls,
switches, gateway
computers and/or edge servers. A network adapter card (e.g., 4050) or network
interface in each
computing/processing device receives computer readable program instructions
from the network
and forwards the computer readable program instructions for storage in a
computer readable
storage medium within the computing system.
[0105] Computer readable program instructions for carrying out operations of
the present
disclosure may be assembler instructions, instruction-set-architecture (ISA)
instructions,
machine instructions, machine dependent instructions, microcode, firmware
instructions, state-
setting data, or either source code or object code written in any combination
of one or more
programming languages, including an object oriented programming language such
as Smalltalk,
C++ or the like, and conventional procedural programming languages, such as
the "C"
programming language or similar programming languages. The computer readable
program
instructions may execute entirely on the user's computer, partly on the user's
computer, as a
stand-alone software package, partly on the user's computer and partly on a
remote computer or
entirely on the remote computer or server. In the latter scenario, the remote
computer may be
connected to the computing system (e.g., 4000) through any type of network,
including a LAN or
a WAN, or the connection may be made to an external computer (for example,
through the
Internet using an Internet Service Provider). In an exemplary embodiment,
electronic circuitry
including, for example, programmable logic circuitry, field-programmable gate
arrays (FPGA),
or programmable logic arrays (PLA) may execute the computer readable program
instructions by
utilizing state information of the computer readable program instructions to
personalize the
electronic circuitry, in order to perform aspects of the present disclosure.
[0106] Aspects of the present disclosure are described herein with reference
to flowchart
illustrations and/or block diagrams of methods, system (or device), and
computer program
products (or computer readable medium). It will be understood that each block
of the flowchart
illustrations and/or block diagrams, and combinations of blocks in the
flowchart illustrations
and/or block diagrams, can be implemented by computer readable program
instructions.
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[0107] These computer readable program instructions may be provided to a
processor of a
general-purpose computer, special purpose computer, or other programmable data
processing
apparatus to produce a machine, such that the instructions, which execute via
the processor of the
computer or other programmable data processing apparatus, create means for
implementing the
functions/acts specified in the flowchart and/or block diagram block or
blocks. These computer
readable program instructions may also be stored in a computer readable
storage medium that
can direct a computer, a programmable data processing apparatus, and/or other
devices to
function in a particular manner, such that the computer readable storage
medium having
instructions stored therein comprises an article of manufacture including
instructions which
implement aspects of the function/act specified in the flowchart and/or block
diagram block or
blocks.
[0108] The computer readable program instructions may also be loaded onto a
computer, other
programmable data processing apparatus, or other device to cause a series of
operational steps to
be performed on the computer, other programmable apparatus or other device to
produce a
computer implemented process, such that the instructions which execute on the
computer, other
programmable apparatus, or other device implement the functions/acts specified
in the flowchart
and/or block diagram block or blocks.
[0109] The flowchart and block diagrams in the Figures illustrate the
architecture, functionality,
and operation of possible implementations of systems, methods, and computer
program products
according to various embodiments of the present disclosure. In this regard,
each block in the
flowchart or block diagrams may represent a module, segment, or portion of
instructions, which
comprises one or more executable instructions for implementing the specified
logical function(s).
In some alternative implementations, the functions noted in the block may
occur out of the order
noted in the figures. For example, two blocks shown in succession may, in
fact, be executed
substantially concurrently, or the blocks may sometimes be executed in the
reverse order,
depending upon the functionality involved. It will also be noted that each
block of the block
diagrams and/or flowchart illustration, and combinations of blocks in the
block diagrams and/or
flowchart illustration, can be implemented by special purpose hardware-based
systems that
perform the specified functions or acts or carry out combinations of special
purpose hardware
and computer instructions.
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[0110] The corresponding structures, materials, acts, and equivalents of all
means or step plus
function elements, if any, in the claims below are intended to include any
structure, material, or
act for performing the function in combination with other claimed elements as
specifically
claimed. The description of the present disclosure has been presented for
purposes of illustration
and description but is not intended to be exhaustive or limited to the present
disclosure in the
form disclosed. Many modifications and variations will be apparent to those of
ordinary skill in
the art without departing from the scope and spirit of the present disclosure.
The embodiment
was chosen and described in order to best explain the principles of the
present disclosure and the
practical application, and to enable others of ordinary skill in the art to
understand the present
disclosure for various embodiments with various modifications as are suited to
the particular use
contemplated.
[0111] While the present invention has been particularly shown and described
with respect to
preferred embodiments thereof, it will be understood by those skilled in the
art that the foregoing
and other changes in forms and details may be made without departing from the
spirit and scope
of the present invention. It is therefore intended that the present invention
not be limited to the
exact forms and details described and illustrated but fall within the scope of
the appended claims.
