# US 9,437,213 B2 · Voice signal enhancement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,213 B2 - Document ID: US9437213B2 - Status: Granted - Kind: B2 - Application number: 13/589,954 - Filed: 2012-08-20 - Published: 2013-09-05 - Granted: 2016-09-06 - Earliest claimed: 2012-03-05 - Assignees: Malaspina Labs (Barbados) Inc. - Applicants: Pierre Zakarauskas; Alexander Escott; Clarence S. H. Chu; Shawn E. Stevenson - Inventors: Pierre Zakarauskas; Alexander Escott; Clarence S. H. Chu; Shawn E. Stevenson - Web page: https://patentgrep.com/patent/US9437213B2 ## CPC - G10L 21/0324: Details of processing therefor - G10L 21/0208: Noise filtering - G10L 21/0308: characterised by the type of parameter measurement, e.g. correlation techniques, zero crossing techniques or predictive techniques - G10L 21/0364: for improving intelligibility - G10L 2021/02082: {the noise being echo, reverberation of the speech} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING ## Abstract Implementations include systems, methods and/or devices operable to enhance the intelligibility of a target speech signal by targeted voice model based processing of a noisy audible signal. In some implementations, an amplitude-independent voice proximity function voice model is used to attenuate signal components of a noisy audible signal that are unlikely to be associated with the target speech signal and/or accentuate the target speech signal. In some implementations, the target speech signal is identified as a near-field signal, which is detected by identifying a prominent train of glottal pulses in the noisy audible signal. Subsequently, in some implementations systems, methods and/or devices perform a form of computational auditory scene analysis by converting the noisy audible signal into a set of narrowband time-frequency units, and selectively accentuating the time-frequency units associated with the target speech signal and deemphasizing others using information derived from the identification of the glottal pulse train. ## Claims ### Claim 1 A method of discriminating relative to a voice signal, the method comprising: receiving, via one or more audible sensors, an audible signal including a target voice signal; converting the audible signal into a corresponding plurality of wideband time-frequency units, wherein the time dimension of each time-frequency unit includes at least one of a plurality of sequential intervals, and wherein the frequency dimension of each time-frequency unit includes at least one of a plurality of wide sub-bands; calculating one or more characterizing metrics from the plurality of wideband time-frequency units; calculating a gain function from one or more characterizing metrics calculated from the plurality of wideband time-frequency units; converting the audible signal into a corresponding plurality of narrowband time-frequency units; applying the gain function, calculated from the plurality of wideband time-frequency units, to the plurality of narrowband time-frequency units to produce a corresponding plurality of narrowband gain-corrected time-frequency units; converting the plurality of narrowband gain-corrected time-frequency units into a corrected audible signal, wherein the corrected audible signal includes an improved target voice signal relative to the received audible signal; and outputting the corrected audible signal through an output device. ### Claim 2 (depends on 1) The method of claim 1, further comprising receiving the audible signal from a single audio sensor device. ### Claim 3 (depends on 1) The method of claim 1, further comprising receiving the audible signal from a plurality of audio sensors. ### Claim 4 (depends on 1) The method of claim 1, wherein the plurality of wide sub-bands is contiguously distributed throughout the frequency spectrum associated with human speech. ### Claim 5 (depends on 1) The method of claim 1, wherein converting the audible signal into the corresponding plurality of wideband time-frequency units includes applying a Fast Fourier Transform to the audible signal. ### Claim 6 (depends on 1) The method of claim 1, wherein the one or more characterizing metrics comprises: a strength metric associated the number of glottal pulses identified in the plurality of wideband time-frequency units; a relative period value indicative of how far an identified period in a respective wide sub-band is from an identified dominant period; and an autocorrelation coefficient associated with an identified glottal pulse in a respective sub-band. ### Claim 7 (depends on 6) The method of claim 6, wherein one or more of the strength metric, the relative period value and the autocorrelation coefficient are determined from one or more outputs of a voice activity detector. ### Claim 8 (depends on 1) The method of claim 1, further comprising calculating a respective signal-to-noise ratio for each narrow sub-band, and wherein the respective signal-to-noise ratios are included in the calculation of the gain function. ### Claim 9 (depends on 1) The method of claim 1, wherein converting the plurality of narrowband gain-corrected time-frequency units into the corrected audible signal comprises re-synthesizing the audible signal from the plurality of narrowband gain-corrected time-frequency units using an inverse Fast Fourier Transform. ### Claim 10 (depends on 1) The method of claim 1, wherein calculating the gain function includes utilizing a sigmoid function to covert one or more of the characterizing metrics into a respective gain. ### Claim 11 A method of discriminating against far field audible components, the method comprising: receiving, via one or more audible sensors, an audible signal including a target voice signal; converting the audible signal into a corresponding plurality of time-frequency units, wherein the time dimension of each time-frequency unit includes at least one of a plurality of sequential intervals, and wherein the frequency dimension of each time-frequency unit includes at least one of a plurality of sub-bands; calculating one or more characterizing metrics from the plurality of time-frequency units associated with near field audible components; calculating a discriminating function from one or more characterizing metrics calculated from the plurality of wideband time-frequency units; applying the discriminating function, calculated from the plurality of wideband time-frequency units, to the plurality of time-frequency units to produce a corresponding plurality of corrected time-frequency units; converting the plurality of corrected time-frequency units into a corrected audible signal, wherein the corrected audible signal includes an improved target voice signal relative to the received audible signal; and outputting the corrected audible signal through an output device. ### Claim 12 A voice signal enhancement device to discriminate relative to a voice signal, the device comprising: one or more audio sensors configured to receive and audible signal including a target voice signal; a first conversion module configured to convert the audible signal into a corresponding plurality of wideband time-frequency units, wherein the time dimension of each time-frequency unit includes at least one of a plurality of sequential intervals, and wherein the frequency dimension of each time-frequency unit includes at least one of a plurality of wide sub-bands; a second conversion module configured to convert the audible signal into a corresponding plurality of narrowband time-frequency units; a metric calculator configured to calculate one or more characterizing metrics from the plurality of wideband time-frequency units; a gain calculator configured to calculate a gain function from one or more characterizing metrics calculated from the plurality of wideband time-frequency units; a filtering module configured to apply the gain function, calculated from the plurality of wideband time-frequency units, to the plurality of narrowband time-frequency units to produce a corresponding plurality of narrowband gain-corrected time-frequency units; a third conversion module configured to convert the plurality of narrowband gain-corrected time-frequency units into a corrected audible signal, wherein the corrected audible signal includes an improved target voice signal relative to the received audible signal; and an output device configured to output the corrected audible signal. ### Claim 13 (depends on 12) The device of claim 12, further comprising an audio sensor to receive the audible signal. ### Claim 14 (depends on 12) The device of claim 12, wherein at least one of the first conversion module and the second conversion module utilizes a Fast Fourier Transform. ### Claim 15 (depends on 12) The device of claim 12, wherein the third conversion module utilizes an Inverse Fast Fourier Transform. ### Claim 16 (depends on 12) The device of claim 12, wherein the metric calculator is operable to determine at least one of: a strength metric associated the number of glottal pulses identified in the plurality of wideband time-frequency units; a relative period value indicative of how far an identified period in a respective wide sub-band is from an identified dominant period; and an autocorrelation coefficient associated with an identified glottal pulse in a respective sub-band. ### Claim 17 (depends on 16) The device of claim 16, further comprising a voice activity detector, and wherein one or more of the strength metric, the relative period value and the autocorrelation coefficient are determined from one or more outputs of the voice activity detector. ### Claim 18 (depends on 12) The device of claim 12, further comprising a narrowband signal-to-noise estimator to determine a respective signal-to-noise ratio for each narrow sub-band, and wherein the respective signal-to-noise ratios are included in the calculation of the gain function. ### Claim 19 A voice signal enhancement device to discriminate relative to a voice signal, the device comprising: means for receiving an audible signal including a target voice signal; means for converting the audible signal into a corresponding plurality of wideband time-frequency units, wherein the time dimension of each time-frequency unit includes at least one of a plurality of sequential intervals, and wherein the frequency dimension of each time-frequency unit includes at least one of a plurality of wide sub-bands; means for converting the audible signal into a corresponding plurality of narrowband time-frequency units; means for calculating one or more characterizing metrics from the plurality of wideband time-frequency units; means for calculating gain function from one or more characterizing metrics calculated from the plurality of wideband time-frequency units; means for applying the gain function, calculated from the plurality of wideband time-frequency units, to the plurality of narrowband time-frequency units to produce a corresponding plurality of narrowband gain-corrected time-frequency units; means for converting the plurality of narrowband gain-corrected time-frequency units into a corrected audible signal, wherein the corrected audible signal includes an improved target voice signal relative to the received audible signal; and means for outputting the corrected audible signal. ### Claim 20 A voice signal enhancement device to discriminate relative to a voice signal, the device comprising: one or more audio sensors configured to receive and audible signal including a target voice signal; a processor; a memory including instructions, that when executed by the processor cause the device to: convert an audible signal into a corresponding plurality of wideband time-frequency units, wherein the time dimension of each time-frequency unit includes at least one of a plurality of sequential intervals, and wherein the frequency dimension of each time-frequency unit includes at least one of a plurality of wide sub-bands; convert the audible signal into a corresponding plurality of narrowband time-frequency units; calculate one or more characterizing metrics from the plurality of wideband time-frequency units; calculate gain function from one or more characterizing metrics calculated from the plurality of wideband time-frequency units; apply the gain function, calculated from the plurality of wideband time-frequency units, to the plurality of narrowband time-frequency units to produce a corresponding plurality of narrowband gain-corrected time-frequency units; convert the plurality of narrowband gain-corrected time-frequency units into a corrected audible signal, wherein the corrected audible signal includes an improved target voice signal relative to the received audible signal; and output the corrected audible signal through an output device.