# US 10,872,594 B2 · Device and method for stereo noise cancellation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,594 B2 - Document ID: US10872594B2 - Status: Granted - Kind: B2 - Application number: 16/265,404 - Filed: 2019-02-01 - Published: 2020-02-20 - Granted: 2020-12-22 - Earliest claimed: 2018-08-27 - Applicants: Sogang University Research & Business Development Foundation - Inventors: Hyung Min Park; Byung Joon Cho - Web page: https://patentgrep.com/patent/US10872594B2 ## CPC - G10K 11/17853: {of the filter} - H04M 9/082: {using echo cancellers (echo cancellers per se H04B3/23)} - G10K 11/17823: {Reference signals, e.g. ambient acoustic environment} - G10K 2210/3028: Filtering, e.g. Kalman filters or special analogue or digital filters - H04R 3/02: for preventing acoustic reaction {, i.e. acoustic oscillatory feedback (specially adapted for hearing aids H04R25/453)} - H04R 5/04: Circuit arrangements, {e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments (combinations of amplifiers H03F3/68; stereophonic systems H04S)} - H04R 2227/007: Electronic adaptation of audio signals to reverberation of the listening space for PA - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) - 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) ## Abstract According to an embodiment, a noise cancellation method comprises updating a first far-end channel filter according to a first variance yielded based on an input signal and a first far-end signal included in the input signal, providing a first output signal obtained by removing a first far-end noise signal from the input signal through the first far-end channel filter, updating a second far-end channel filter according to a second variance yielded based on the first output signal and a second far-end signal included in the input signal, and providing a second output signal obtained by removing a second far-end noise signal from the first output signal through the second far-end channel filter. ## Claims ### Claim 1 A noise cancellation method, comprising: updating a first far-end channel filter according to a first variance yielded based on an input signal and a first far-end signal included in the input signal; providing a first output signal obtained by removing a first far-end noise signal from the input signal through the first far-end channel filter; updating a second far-end channel filter according to a second variance yielded based on the first output signal and a second far-end signal included in the input signal; and providing a second output signal obtained by removing a second far-end noise signal from the first output signal through the second far-end channel filter, wherein updating the first far-end channel filter includes estimating the first variance based on the input signal and the first far-end signal and creating a first cross-correlation vector and a first autocorrelation matrix based on the first variance. ### Claim 2 (depends on 1) The noise cancellation method of claim 1, wherein an initial value of the first variance is obtained by cross correlation between the input signal and the first far-end signal and autocorrelation of the first far-end signal. ### Claim 3 (depends on 1) The noise cancellation method of claim 1, wherein the first cross-correlation vector and the first autocorrelation matrix are updated according to the first variance. ### Claim 4 (depends on 1) The noise cancellation method of claim 1, wherein the first far-end channel filter is updated according to the first cross-correlation vector and the first autocorrelation matrix. ### Claim 5 (depends on 1) The noise cancellation method of claim 1, further comprising: initializing the first variance; and initializing the second variance. ### Claim 6 (depends on 5) The noise cancellation method of claim 5, wherein the first far-end channel filter is updated according to a first cross-correlation vector and a first autocorrelation matrix obtained based on the first variance. ### Claim 7 A noise cancellation method, comprising: updating a first far-end channel filter according to a first variance yielded based on an input signal and a first far-end signal included in the input signal; providing a first output signal obtained by removing a first far-end noise signal from the input signal through the first far-end channel filter; updating a second far-end channel filter according to a second variance yielded based on the first output signal and a second far-end signal included in the input signal; and providing a second output signal obtained by removing a second far-end noise signal from the first output signal through the second far-end channel filter, wherein updating the second far-end channel filter includes estimating the second variance based on the first output signal and the second far-end signal and creating a cross-correlation vector and an autocorrelation matrix based on the second variance. ### Claim 8 (depends on 7) The noise cancellation method of claim 7, wherein an initial value of the second variance is obtained by cross correlation between the output signal and the second far-end signal and autocorrelation of the second far-end signal. ### Claim 9 (depends on 7) The noise cancellation method of claim 7, wherein the second cross-correlation vector and the second autocorrelation matrix are updated according to the second variance. ### Claim 10 (depends on 9) The noise cancellation method of claim 9, wherein the second far-end channel filter is updated according to the second cross-correlation vector and the second autocorrelation matrix. ### Claim 11 A noise cancellation method, comprising: providing a first estimated output signal based on a first prior far-end channel filter corresponding to a prior frame, an input signal, and a first far-end signal; updating a first current far-end channel filter corresponding to a current frame according to the first estimated output signal and the first prior far-end channel filter; providing a first output signal obtained by removing a first far-end noise signal from the input signal using the first current far-end channel filter; providing a second estimated output signal based on a second prior far-end channel filter corresponding to the prior frame, the first output signal, and a second far-end signal; updating the second current far-end channel filter corresponding to the current frame according to the second estimated output signal and the second prior far-end channel filter; and providing a second output signal obtained by removing a second far-end noise signal from the first output signal using the second current far-end channel filter, wherein updating the first current far-end channel filter includes estimating a first variance based on the first estimated output signal and creating a first inverse autocorrelation matrix based on the first variance. ### Claim 12 (depends on 11) The noise cancellation method of claim 11, wherein the first variance is determined by the first estimated output signal provided based on the first prior far-end channel filter. ### Claim 13 (depends on 12) The noise cancellation method of claim 12, wherein the first variance is determined by the product of a first weight and the square of the absolute value of the first estimated output signal. ### Claim 14 (depends on 13) The noise cancellation method of claim 13, wherein the first current far-end channel filter converges to a constant value. ### Claim 15 (depends on 11) The noise cancellation method of claim 11, wherein updating the second current far-end channel filter includes estimating a second variance based on the second estimated output signal and creating a second inverse autocorrelation matrix based on the second variance. ### Claim 16 (depends on 15) The noise cancellation method of claim 15, wherein the second variance is determined by the second estimated output signal provided based on the second prior far-end channel filter. ### Claim 17 (depends on 16) The noise cancellation method of claim 16, wherein the second variance is determined by the product of a second weight and the square of the absolute value of the second estimated output signal.