# US 9,437,199 B2 · Method and device for separating signals by minimum variance spatial filtering under linear constraint > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,199 B2 - Document ID: US9437199B2 - Status: Granted - Kind: B2 - Application number: 14/431,309 - Filed: 2013-09-25 - Published: 2015-08-27 - Granted: 2016-09-06 - Earliest claimed: 2012-09-27 - Assignees: Universite Bordeaux 1; Centre National De Las Recherche Scientifique (C - Applicants: Universite Bordeaux 1; Centre National De La Recherche Scientifique (Cnrs) - Inventors: Sylvain Marchand; Stanislaw Gorlow - Web page: https://patentgrep.com/patent/US9437199B2 ## CPC - G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing - G10L 19/018: Audio watermarking, i.e. embedding inaudible data in the audio signal - G10L 21/028: using properties of sound source - G10L 21/0308: characterised by the type of parameter measurement, e.g. correlation techniques, zero crossing techniques or predictive techniques - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract The invention relates to a method and the associated device 1 for separating one or more particular digital audio source signals (si) contained in a mixed multichannel digital audio signal (smix) obtained by mixing a plurality of digital audio source signals (s1, . . . , sp). According to the invention: the modulus of the amplitude or the normalized power of the particular source signal(s) (si) is determined from representative values of said particular source signal(s) contained in the mixed signal; and then linearly constrained minimum variance spatial filtering is performed on the mixed signal in order to obtain each particular source signal (s′i), said filtering being based on the distribution of said particular source signal between at least two channels of the mixed signal, and the modulus of the amplitude or the normalized power of said particular source signal is used as a linear constraint of the filter. ## Claims ### Claim 1 A method of separating, at least in part, one or more particular digital audio source signals contained in a mixed multichannel digital audio signal, the mixed signal being obtained by mixing a plurality of digital audio source signals and including representative values of the particular source signal(s), the method comprising: determining the modulus of the amplitude or the normalized power of the particular source signal(s) from the representative values in the time-frequency plane of said particular source signal(s) contained in the mixed signal; and then performing linearly constrained minimum variance spatial filtering in order to obtain, at least in part, each particular source signal, said filtering being based on the distribution of said particular source signal between at least two channels of the mixed signal, and the modulus of the amplitude or the normalized power of said particular source signal being used as a linear constraint of the filter. ### Claim 2 (depends on 1) The method according to claim 1, wherein the mixed signal includes representative values of the particular source signal(s) for at least two channels of the mixed signal, and wherein, prior to performing spatial filtering, the mixed signal and said representative values of the particular signals are used to determine the distribution of each particular source signal between said at least two channels of the mixed signal. ### Claim 3 (depends on 1) The method according to claim 1, wherein the distribution of the particular source signal(s) between at least two channels of said mixed signal is received as input. ### Claim 4 (depends on 1) The method according to claim 1, wherein determining the modulus of the amplitude or the normalized power of the particular source signal(s) comprises extracting representative values of the particular source signals that have been inserted into the mixed signal. ### Claim 5 (depends on 1) The method according to claim 1, wherein the modulus of the amplitude or the normalized power of said particular source signal are spectro-temporal values. ### Claim 6 A device for separating, at least in part, one or more particular digital audio source signals contained in a multichannel mixed digital audio signal, the mixed signal being obtained by mixing a plurality of digital audio source signals and including representative values of the particular source signal(s), the device comprising: determination means for determining the modulus of the amplitude or the normalized power of the particular source signal(s) from the representative values in the time-frequency plane of said particular source signal(s) contained in the mixed signal; and a linearly constrained minimum variance spatial filter adapted to isolate, at least in part, each particular source signal from the mixed signal, said filter being based on the distribution of said particular source signal between at least two channels of the mixed signal, and the modulus of the amplitude or the normalized power of said particular source signal being used as a linear constraint. ### Claim 7 (depends on 6) The device according to claim 6, wherein the mixed signal includes representative values of the particular source signal(s) for at least two channels of the mixed signal, the device including determination means for determining the distribution of each particular source signal between said at least two channels of the mixed signal from the mixed signal and from said representative values of the particular source signals. ### Claim 8 (depends on 6) The device according to claim 6, also including an extractor configured to extract the representative values of the particular source signal(s) that have been inserted in the mixed signal. ### Claim 9 (depends on 3) The method according to claim 3, wherein the distribution of the particular source signal(s) between at least two channels of said mixed signal are received in the mixed signal. ### Claim 10 (depends on 4) The method according to claim 4, wherein determining the modulus of the amplitude or the normalized power of the particular source signal(s) comprises extracting representative values of the particular source signals that have been inserted into the mixed signal by watermarking. ### Claim 11 (depends on 8) The device according to claim 8, wherein the extractor is configured to extract the representative values based on watermarking.