Technique for localizing sound source
AssigneeHyundai Motor Company
InventorsJong Hyun Lee, Myung Han Lee, Mun Hwan Cho, Kang Duck Ih
Life of this patent
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Abstract
Disclosed is a technique for localizing a sound source. In the technique, a sound pressure signal measured by microphones is acquired using a spherical microphone array sensor where the microphones are fixedly arranged on a surface of a spherical body. A sound pressure distribution on the surface of the spherical body is obtained by a controller from a sound pressure calculation formula for calculating a sound pressure at a certain location of a spherical surface using the sound pressure signal measured by the microphones as an input value. A location of the sound source is estimated from the obtained sound pressure distribution.
Claims8
A method for localizing a sound source, comprising:
- acquiring, by a controller, a sound pressure signal measured by microphones, using a spherical microphone array sensor wherein the microphones are fixedly arranged on a surface of a spherical body;
- obtaining a sound pressure distribution on the surface of the spherical body from a sound pressure calculation formula for calculating a sound pressure at a certain location of a spherical surface using the sound pressure signal measured by the microphones as an input value;
- and
- estimating a location of the sound source from the obtained sound pressure distribution,
- wherein, from Equation (1) below the sound pressure calculation formula is obtained by meeting r=a (here, a is a radius of the spherical body) and limiting a sound field distribution order n to a maximum order N of Equation (2) below that considers a total number of microphones;
- p
-
- (
- r
- ,
- θ
- ,
- ϕ
- )
- =
- ∑
- n
- =
- 0
- ∞
-
- j
- n
-
- (
- kr
- )
- j
- n
-
- (
- ka
- )
-
- ∑
- m
- =
- -
- n
- n
-
- Y
- n
- m
-
- (
- θ
- ,
- ϕ
- )
-
- ∫
- 0
- 2
-
- π
-
- ∫
- 0
- π
-
- p
-
- (
- a
- ,
- θ
- 0
- ,
- ϕ
- o
- )
-
- Y
- n
- m
-
- (
- θ
- 0
- ,
- ϕ
- 0
- )
- *
-
- sin
-
-
- θ
-
- ⅆ
- θ
-
- ⅆ
- ϕ
- (
- 1
- )
- where jn(kr) is a spherical Bessel function, n is an order of sound field distribution, m={−n, −n−1, . . . , 0, 1, . . . , n−1, n}, Ynm(θ,φ) are spherical harmonic functions, r denotes a radius of a sphere, θ denotes a horizontal angle of a spherical coordinate, φ denotes a vertical angle of the spherical coordinate, θ0 and φo denote the horizontal angle and the vertical angle of microphone location respectively, and p(a,θ0,φo) denotes a sound pressure measured at each microphone location on the surface of the spherical body;
- and
- M≧(N+1)2 (2)
- where M is a total number of microphones, and N is a maximum order.
A system for localizing a sound source, comprising:
- a spherical microphone array sensor configured to acquire a sound pressure signal Measured by microphones, wherein the microphones are fixedly arranged on a surface of a spherical body;
- and
- a controller configured to obtain a sound pressure distribution on the surface of the spherical body from a sound pressure calculation formula for calculating a sound pressure at a certain location of a spherical surface using the sound pressure signal measured by the microphones as an input value, and estimate a location of the sound source from the obtained sound pressure distribution,
- wherein, from Equation (1) below the sound pressure calculation formula is obtained by meeting r=a (here, a is a radius of the spherical body) and limiting a sound field distribution order n to a maximum order N of Equation (2) below that considers a total number of microphones;
- p
-
- (
- r
- ,
- θ
- ,
- ϕ
- )
- =
- ∑
- n
- =
- 0
- ∞
-
- j
- n
-
- (
- kr
- )
- j
- n
-
- (
- ka
- )
-
- ∑
- m
- =
- -
- n
- n
-
- Y
- n
- m
-
- (
- θ
- ,
- ϕ
- )
-
- ∫
- 0
- 2
-
- π
-
- ∫
- 0
- π
-
- p
-
- (
- a
- ,
- θ
- 0
- ,
- ϕ
- o
- )
-
- Y
- n
- m
-
- (
- θ
- 0
- ,
- ϕ
- 0
- )
- *
-
- sin
-
-
- θ
-
- ⅆ
- θ
-
- ⅆ
- ϕ
- (
- 1
- )
- where jn(kr) is a spherical Bessel function, n is an order of sound field distribution, m={−n, −n−1, . . . , 0, 1, . . . , n−1, n}, Ynm(θ,φ) are spherical harmonic functions, r denotes a radius of a sphere, θ denotes a horizontal angle of a spherical coordinate, φ denotes a vertical angle of the spherical coordinate, θ0 and φo denote the horizontal angle and the vertical angle of microphone location, respectively, and p(a,θ0,φo) denotes a sound pressure measured at each microphone location on the surface of the spherical body;
- and
- M≧(N+1)2 (2)
- where M is a total number of microphones, and N is a maximum order.
Dependencies are inferred from the claim text.