# US 10,319,391 B2 · Impulsive noise suppression > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,391 B2 - Document ID: US10319391B2 - Status: Granted - Kind: B2 - Application number: 15/569,555 - Filed: 2016-04-27 - Published: 2018-10-18 - Granted: 2019-06-11 - Earliest claimed: 2015-04-28 - Assignees: Dolby Laboratories Licensing Corporation - Applicants: Dolby Laboratories Licensing Corporation - Inventors: David Gunawan; Dong Shi; Glenn N. Dickins - Web page: https://patentgrep.com/patent/US10319391B2 ## CPC - G10L 21/0208: Noise filtering - G10L 21/034: Automatic adjustment - H04R 1/326: {for microphones (H04R1/34 and H04R1/40 take precedence)} - G10L 25/48: specially adapted for particular use - H04R 2410/03: Reduction of intrinsic noise in microphones - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - 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 Example embodiments disclosed herein relate to impulsive noise suppression. A method of impulsive noise suppression in an audio signal is disclosed. The method includes determining an impulsive noise related feature from a current frame of the audio signal. The method also includes detecting an impulsive noise in the current frame based on the impulsive noise related feature, and in response to detecting the impulsive noise in the current frame, applying a suppression gain to the current frame to suppress the impulsive noise. Corresponding system and computer program product of impulsive noise suppression in an audio signal are also disclosed. ## Claims ### Claim 1 A method of impulsive noise suppression in an audio signal, comprising: determining an impulsive noise related feature from a current frame of the audio signal; detecting an impulsive noise in the current frame based on the impulsive noise related feature; and in response to detecting the impulsive noise in the current frame, applying a suppression gain to the current frame to suppress the impulsive noise, wherein determining an impulsive noise related feature from a current frame of the audio signal comprises: determining a spectral tilt of the current frame by comparing powers in a high frequency range and a low frequency range of the current frame, the spectral tilt indicating a shape of the current frame in frequency domain. ### Claim 2 (depends on 1) The method according to claim 1, wherein determining an impulsive noise related feature from a current frame of the audio signal comprises: determining a delta power of the current frame by comparing powers in a high frequency range of the current frame and a previous frame of the audio signal, the delta power indicating a shape of the current frame in time domain. ### Claim 3 (depends on 1) The method according to claim 1, wherein determining an impulsive noise related feature from a current frame of the audio signal comprises: determining a spatial proximity from a sound source of the audio signal to a device that captures the audio signal. ### Claim 4 (depends on 3) The method according to claim 3, wherein the device captured the audio signal has a first microphone and a second microphone, and wherein determining the spatial proximity comprises: determining a correlation between a first mono signal acquired by the first microphone and a second mono signal acquired by the second microphone. ### Claim 5 (depends on 3) The method according to claim 3, wherein determining the spatial proximity comprises: determining a first strength of the audio signal in a first direction; determining a second strength of the audio signal in a second direction; and determining the spatial proximity by comparing the first and second strengths. ### Claim 6 (depends on 1) The method according to claim 1, wherein applying a suppression gain to the current frame in response to detecting the impulsive noise in the current frame comprises: in response to detecting the impulsive noise in the current frame, determining the suppression gain based on a predetermined noise power of a previous impulsive noise and a power of the current frame; and applying the determined suppression gain to the current frame to suppress the impulsive noise. ### Claim 7 (depends on 1) The method according to claim 1, further comprising: in response to detecting no impulsive noise in the current frame and detecting an impulsive noise in a previous frame, determining a decayed noise power based on a room decay factor and a predetermined noise power of a previous impulsive noise; determining another suppression gain based on the decayed noise power and a power of the current frame; and applying the other suppression gain to the current frame to suppress a decayed version of the impulsive noise. ### Claim 8 (depends on 1) The method according to claim 1, further comprising: determining whether to suppress the impulsive noise or not in the current frame by deciding whether a predefined criteria is satisfied. ### Claim 9 A system of impulsive noise suppression in an audio signal, comprising: a feature determination unit configured to determine an impulsive noise related feature from a current frame of the audio signal; a noise detection unit configured to detect an impulsive noise in the current frame based on the impulsive noise related feature; and a noise suppression unit configured to apply a suppression gain to the current frame in response to detecting the impulsive noise in the current frame so as to suppress the impulsive noise, wherein the feature determination unit is configured to determine a delta power of the current frame by comparing powers in a high frequency range of the current frame and a previous frame of the audio signal, the delta power indicating a shape of the current frame in time domain. ### Claim 10 (depends on 9) The system according to claim 9, wherein the feature determination unit is configured to determine a spectral tilt of the current frame by comparing powers in a high frequency range and a low frequency range of the current frame, the spectral tilt indicating a shape of the current frame in frequency domain. ### Claim 11 (depends on 9) The system according to claim 9, wherein the feature determination unit is configured to determine a spatial proximity from a sound source of the audio signal to a device that captures the audio signal. ### Claim 12 (depends on 11) The system according to claim 11, wherein the device captured the audio signal has a first microphone and a second microphone, and wherein the feature determination unit is configured to determine the spatial proximity by determining a correlation between a first mono signal acquired by the first microphone and a second mono signal acquired by the second microphone. ### Claim 13 (depends on 11) The system according to claim 11, the feature determination unit is further configured to: determine a first strength of the audio signal in a first direction; determine a second strength of the audio signal in a second direction; and determine the spatial proximity by comparing the first and second strengths. ### Claim 14 (depends on 9) The system according to claim 9, wherein the noise suppression unit is configured to: in response to detecting the impulsive noise in the current frame, determine the suppression gain based on a predetermined noise power of a previous impulsive noise and a power of the current frame; and apply the determined suppression gain to the current frame to suppress the impulsive noise. ### Claim 15 (depends on 9) The system according to claim 9, further comprising: a decayed power determination unit configured to determine a decayed noise power based on a room decay factor and a predetermined noise power of a previous impulsive noise in response to detecting no impulsive noise in the current frame and detecting an impulsive noise in a previous frame; a suppression gain determination unit configured to determine another suppression gain based on the decayed noise power and a power of the current frame; and a decayed noise suppression unit configured to apply the other suppression gain to the current frame to suppress a decayed version of the impulsive noise. ### Claim 16 (depends on 9) The system according to claim 9, further comprising: a noise suppression decision unit configured to determine whether to suppress the impulsive noise or not in the current frame by deciding whether a predefined criteria is satisfied. ### Claim 17 A computer program product of impulsive noise suppression in an audio signal, comprising a computer program tangibly embodied on a non-transitory machine readable medium, the computer program containing program code for performing operations comprising: determining an impulsive noise related feature from a current frame of the audio signal; detecting an impulsive noise in the current frame based on the impulsive noise related feature; and in response to detecting the impulsive noise in the current frame, applying a suppression gain to the current frame to suppress the impulsive noise, wherein applying a suppression gain to the current frame in response to detecting the impulsive noise in the current frame comprises: in response to detecting the impulsive noise in the current frame, determining the suppression gain based on a predetermined noise power of a previous impulsive noise and a power of the current frame; and applying the determined suppression gain to the current frame to suppress the impulsive noise. ### Claim 18 (depends on 17) The computer program product according to claim 17, wherein determining an impulsive noise related feature from a current frame of the audio signal comprises: determining a spatial proximity from a sound source of the audio signal to a device that captures the audio signal. ### Claim 19 (depends on 18) The computer program product according to claim 18, wherein the device captured the audio signal has a first microphone and a second microphone, and wherein determining the spatial proximity comprises: determining a correlation between a first mono signal acquired by the first microphone and a second mono signal acquired by the second microphone. ### Claim 20 (depends on 18) The computer program product according to claim 18, the operations further comprising: in response to detecting no impulsive noise in the current frame and detecting an impulsive noise in a previous frame, determining a decayed noise power based on a room decay factor and a predetermined noise power of a previous impulsive noise; determining another suppression gain based on the decayed noise power and a power of the current frame; and applying the other suppression gain to the current frame to suppress a decayed version of the impulsive noise.