Patent ID: 9681220
Date: 2017-06-13
CPC Classifications: G10L,H04R

Claim:
1. Method for spatial filtering of at least one sound signal (M.sub.0; W(n)), the method characterized in that it includes the following steps: generation of a first captured sound signal ( 23 ; M.sub.1; M.sub.1.sup.1, M.sub.1.sup.−1; X(n), Y(n)) by capturing of the at least one sound signal by a first microphone ( 12 .sub.1), whereby the first microphone ( 12 .sub.1) is characterized by a first directivity pattern; generation of a second captured sound signal ( 23 ; M.sub.2; M.sub.2.sup.1, M.sub.2.sup.−1; U(n), V(n)) by capturing of the at least one sound signal by a second microphone ( 12 .sub.2), whereby the second microphone ( 12 .sub.2) is characterized by a second directivity pattern; and generation of a third captured sound signal ( 23 ; M.sub.0; W(n)) by capturing of the at least one sound signal by a third microphone ( 12 .sub.0), whereby the third microphone ( 12 .sub.0) is characterized by a third directivity pattern; so that the first microphone ( 12 .sub.1), the second microphone ( 12 .sub.2) and the third microphone ( 12 .sub.0) constitute one microphone array ( 12 ), characterized by a multiple of directivity patterns of different orders, whereby the first directivity pattern as well as the second directivity pattern and the third directivity pattern constitute respectively one particular directivity pattern of said multiple of directivity patterns of different orders; performing a short-time Fourier transformation of the captured sound signals ( 23 ; M.sub.0, M.sub.1, M.sub.2; M.sub.1.sup.1, M.sub.1.sup.−1, M.sub.2.sup.1, M.sub.2.sup.−1; X(n), Y(n), U(n), V(n), W(n)); measuring a cross-pattern correlation or a cross-pattern coherence as the correlation or coherence between two of the captured sound signals ( 23 ; M.sub.1, M.sub.2; M.sub.1.sup.1, M.sub.1.sup.−1, M.sub.2.sup.1, M.sub.2.sup.−1; X(n), Y(n), U(n), V(n)) having the positive-phase maximum in directivity response towards a desired look direction (.quadrature.) in each time frequency position; calculation of a gain factor (G.sup.+) for each time-frequency position using the cross-pattern correlation or the cross-pattern coherence based on time-averaged correlation or coherence between the first captured sound signal ( 23 ; M.sub.1; M.sub.1.sup.1, M.sub.1.sup.−1; X(n), Y(n)) and the second captured sound signal ( 23 ; M.sub.2; M.sub.2.sup.1, M.sub.2.sup.−1; U(n), V(n)) having equal phase for a same look direction; and applying the gain factor (G.sup.+) to the corresponding time-frequency positions in the third captured sound signal ( 23 ; M.sub.0; W(n)).