# US 10,375,472 B2 · Determining azimuth and elevation angles from stereo recordings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,375,472 B2 - Document ID: US10375472B2 - Status: Granted - Kind: B2 - Application number: 15/736,713 - Filed: 2016-07-01 - Published: 2018-07-05 - Granted: 2019-08-06 - Earliest claimed: 2015-07-02 - Assignees: Dolby Laboratories Licensing Corporation - Applicants: Dolby Laboratories Licensing Corporation - Inventors: Nicolas R. Tsingos - Web page: https://patentgrep.com/patent/US10375472B2 ## CPC - H04R 1/406: {microphones} - G10L 19/008: Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing - G10L 19/20: using sound class specific coding, hybrid encoders or object based coding - H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)} - H04S 2400/15: Aspects of sound capture and related signal processing for recording or reproduction - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - H04S: STEREOPHONIC SYSTEMS ## Abstract Input audio data, including first microphone audio signals and second microphone audio signals output by a pair of coincident, vertically-stacked directional microphones, may be received. An azimuthal angle corresponding to a sound source location may be determined, based at least in part on an intensity difference between the first microphone audio signals and the second microphone audio signals. An elevation angle corresponding to a sound source location may be determined, based at least in part on a temporal difference between the first microphone audio signals and the second microphone audio signals. Output audio data, including at least one audio object corresponding to a sound source, may be generated. The audio object may include audio object signals and associated audio object metadata. The audio object metadata may include at least audio object location data corresponding to the sound source location. ## Claims ### Claim 1 A method, comprising: receiving input audio data including first microphone audio signals and second microphone audio signals output by a pair of coincident, vertically-stacked directional microphones; determining, based at least in part on an intensity difference between the first microphone audio signals and the second microphone audio signals, an azimuthal angle corresponding to a sound source location; determining, based at least in part on a temporal difference between the first microphone audio signals and the second microphone audio signals and at least in part on a vertical distance between a first microphone and a second microphone of the pair of coincident, vertically-stacked directional microphones, an elevation angle corresponding to the sound source location; and generating output audio data including at least one audio object corresponding to a sound source, the audio object comprising audio object signals and associated audio object metadata, the audio object metadata including at least audio object location data corresponding to the sound source location. ### Claim 2 (depends on 1) The method of claim 1, further comprising upsampling the input audio data. ### Claim 3 (depends on 2) The method of claim 2, wherein the upsampling is performed prior to determining the elevation angle. ### Claim 4 (depends on 1) The method of claim 1, further comprising splitting the input audio data into sub-bands. ### Claim 5 (depends on 4) The method of claim 4, wherein the generating involves generating a plurality of audio objects, each audio object of the plurality of audio objects corresponding to a sub-band. ### Claim 6 (depends on 5) The method of claim 5, wherein generating the plurality of audio objects involves generating N audio objects, further comprising performing an audio object clustering process on the N audio objects that outputs fewer than N audio objects. ### Claim 7 (depends on 1) The method of claim 1, wherein the audio object location data is based, at least in part, on the azimuthal angle and the elevation angle. ### Claim 8 (depends on 1) The method of claim 1, wherein the azimuthal angle and the elevation angle are determined relative to a first coordinate system, further comprising transforming the audio object location data into coordinates of a second coordinate system. ### Claim 9 (depends on 8) The method of claim 8, further comprising receiving inertial sensor data, wherein transforming the audio object location data into the second coordinate system is based, at least in part, on the inertial sensor data. ### Claim 10 (depends on 1) The method of claim 1, further comprising determining an object size parameter of the sound source. ### Claim 11 (depends on 10) The method of claim 10, wherein determining the object size parameter of the sound source involves determining a statistical variance of azimuthal angles corresponding to the sound source, determining a statistical variance of elevation angles corresponding to the sound source, or determining statistical variances of both azimuthal angles and elevation angles corresponding to the sound source. ### Claim 12 (depends on 11) The method of claim 11, wherein the method involves splitting the input audio data into sub-bands and determining an object size parameter for each of the sub-bands. ### Claim 13 (depends on 10) The method of claim 10, further comprising determining a diffuse residual that corresponds to uncorrelated components of the first microphone audio signals and the second microphone audio signals and representing the diffuse residual as a pair of additional audio objects having a large size and large decorrelation parameters. ### Claim 14 (depends on 1) The method of claim 1, wherein the pair of coincident, vertically-stacked directional microphones comprises a XY stereo microphone system. ### Claim 15 (depends on 1) The method of claim 1, further comprising: determining a cross-correlation function between the first microphone audio signals and the second microphone audio signals; and upsampling the cross-correlation function. ### Claim 16 A method, comprising: receiving input audio data including first microphone audio signals and second microphone audio signals output by a pair of coincident, vertically-stacked directional microphones; determining, based at least in part on an intensity difference between the first microphone audio signals and the second microphone audio signals, an azimuthal angle corresponding to a sound source location; determining, based at least in part on a temporal difference between the first microphone audio signals and the second microphone audio signals, an elevation angle corresponding to the sound source location; determining an object size parameter of the sound source; determining a diffuse residual that corresponds to uncorrelated components of the first microphone audio signals and the second microphone audio signals; representing the diffuse residual as a pair of additional audio objects having a large size and large decorrelation parameters; and generating output audio data including at least one audio object corresponding to a sound source, the audio object comprising audio object signals and associated audio object metadata, the audio object metadata including at least audio object location data corresponding to the sound source location. ### Claim 17 (depends on 16) The method of claim 16, wherein determining the object size parameter of the sound source involves determining a statistical variance of azimuthal angles corresponding to the sound source, determining a statistical variance of elevation angles corresponding to the sound source, or determining statistical variances of both azimuthal angles and elevation angles corresponding to the sound source. ### Claim 18 (depends on 17) The method of claim 17, wherein the method involves splitting the input audio data into sub-bands and determining an object size parameter for each of the sub-bands.