System and method for wind detection and suppression
View Patent ↗In one embodiment, a pickup system includes a wind detector and a wind suppressor. The wind detector has a plurality of analyzers each configured to analyze first and second input signals, and a combiner configured to combine outputs of the plurality of analyzers and issue, based on the combined outputs, a wind level indication signal indicative of wind activity. The analyzers can be selected from a group of analyzers including a spectral slope analyzer, a ratio analyzer, a coherence analyzer, a phase variance analyzer and the like. The wind suppressor has a ratio calculator configured to generate a ratio of the first and second input signals, and a mixer configured to select one of the first or second input signals and to apply to the selected input signal one of first or second panning coefficients based on the wind level indication signal and on the ratio.
1. A pickup system comprising:
a wind detector configured to receive first and second input signals, the wind detector including:
a plurality of analyzers each configured to analyze the first and second input signals; and
a combiner configured to combine outputs of the plurality of analyzers and issue, based on the combined outputs, a wind level indication sinal indicative of wind activity; and
a wind suppressor including:
a ratio calculator configured to generate a ratio of sub-band powers of the first and second input signals; and
a mixer configured to select one of the first or second input signals and to apply to said selected input signal one of first or second panning coefficients based on the wind level indication signal and on the ratio, the other of the first or second input signals being unselected, wherein:
application of the first or second panning coefficients is a function of a ratio of the first and second input signals; and
one of the first or second panning coefficients α is defined as
α=10 −2*WindLevel*(Ratio-RatioTgt)/20 Ratio−RatioTgt<0
where WindLevel is wind detector output signal provided to the wind suppressor, Ratio is a current ratio of the sub-band powers (in dB) for the first and second input signals, and RatioTgt is a pre-selected ratio value for the sub-band powers (in dB) of the first and second input signals.
2. The pickup system of claim 1 , wherein the first and second panning coefficients are related as
α
=
1
+
p
2
r
p
1
(
1
-
β
)
β
=
1
+
p
1
p
2
r
(
1
-
α
)
where α is one of the first or second panning coefficients, β is the other of the first or second panning coefficients, p1 and p2 define a passive array characterizing anticipated processing subsequent to wind suppression, and r is a complex factor defining sub-band relationships between first and second input signal sub-bands for a desired signal.
3. The pickup system of claim 1 , wherein the wind suppressor further comprises a filter to filter the wind level indication signal issuing from the wind detector.
4. A wind suppression method comprising:
receiving, at a wind detector, first and second input signals;
determining, in a processor based ratio calculator, a ratio of sub-band power of first and second input signals;
receiving a wind level indication signal; and
selecting one of the first or second input signals to apply thereto one of first or second panning coefficients based on the wind level indication signal and on the ratio, the other of the first or second input signals being unselected, wherein one of the first or second panning coefficients α is defined as
α=10 −2*WindLevel*(Ratio-RatioTgt)/20 Ratio−RatioTgt<0
where WindLevel represents the wind level indication signal, Ratio is a current ratio of the sub-band powers (in dB) for the first and second input signals, and RatioTgt is a pre-selected ratio target value for the sub-band powers (in dB) of the first and second input signals.
5. The method of claim 4 , further comprising applying to the selected signal at least a portion of the unselected signal.
6. The method of claim 4 , wherein the first and second panning coefficients are related as
α
=
1
+
p
2
r
p
1
(
1
-
β
)
β
=
1
+
p
1
p
2
r
(
1
-
α
)
where α is one of the first or second panning coefficients, β is the other of the first or second panning coefficients, p1 and p2 define a passive array characterizing anticipated processing subsequent to wind suppression, and r is a complex factor defining sub-band relationships between first and second input signal sub-bands for a desired signal.
7. The method of claim 6 , wherein r is defined as:
r= 10 −RatioTgt/10 e −iPhaseTgt
where RatioTgt is a pre-selected sub-band ratio (in dB) value of the first and second input signals, and PhaseTgt is a pre-selected phase difference value between first and second input sub-band signals.