# US 2020/0401211 A1 · Techniques for monitoring and detecting respiration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0401211 A1 - Document ID: US20200401211A1 - Status: Published application - Kind: A1 - Application number: 16/690,900 - Filed: 2019-11-21 - Published: 2020-12-24 - Earliest claimed: 2019-06-24 - Assignees: AppliedVR., Inc. - Applicants: AppliedVR., Inc. - Inventors: Vangelis Lympouridis; Josh Sackman; Eric Espinoza; Aaron Robin; Jonathan Graves - Web page: https://patentgrep.com/patent/US20200401211A1 ## CPC - G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)} - A61B 5/0022: {Monitoring a patient using a global network, e.g. telephone networks, internet} - A61B 5/0816: {Measuring devices for examining respiratory frequency (measuring frequency of electric signals G01R23/00)} - A61B 5/097: Devices for facilitating collection of breath or for directing breath into or through measuring devices - A61B 5/486: {Biofeedback (using electroencephalography [EEG] A61B5/375)} - A61B 5/6803: {Head-worn items, e.g. helmets, masks, headphones or goggles} - A61B 5/6814: {Head} - G06F 3/16: Sound input; Sound output (speech processing G10L) - G10L 21/0316: by changing the amplitude - G10L 25/18: the extracted parameters being spectral information of each sub-band - G10L 25/51: for comparison or discrimination - A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition - A61B 5/681: {Wristwatch-type devices} - G02B 27/0176: {characterised by mechanical features} - G06F 3/165: {Management of the audio stream, e.g. setting of volume, audio stream path} - G06F 2203/011: Emotion or mood input determined on the basis of sensed human body parameters such as pulse, heart rate or beat, temperature of skin, facial expressions, iris, voice pitch, brain activity patterns - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A device for monitoring respiration by a user determines whether sound represented by audio data corresponds to an exhalation. For example, the device receives audio data representing sound, determines a frequency spectrum for the audio data (e.g., amplitude distributions of one or more frequencies, etc.), and identifies various frequency bands of interest. Here, the device identifies a first frequency band corresponding to respiration, a second frequency band corresponding to noise, and a third frequency band corresponding to voice harmonics. The device applies a gain to the first frequency band to create an amplified first frequency band, filters or nulls the second frequency band, and inverts the third frequency band to create an inverted third frequency band. The device determines the frequency spectrum corresponds to an exhalation based on a slope value over the amplitude distributions of the amplified first frequency band and the inverted third frequency band. ## Claims ### Claim 1 A method for monitoring respiration, the method comprising: receiving, by a processor, audio data representing sound detected by an input interface on a device; determining, by the processor, a frequency spectrum of amplitude distributions for one or more frequencies represented by the audio data; identifying, by the processor, a first frequency band including a first set of frequencies associated with respiration, a second frequency band including a second set of frequencies associated with noise, and a third frequency band including a third set of frequencies associated with voice harmonics; applying, by the processor, a gain to the first set of frequencies to create an amplified first frequency band; applying, by the processor, a filter to the second set of frequencies to create a nulled second frequency band; inverting, by the processor, the third set of frequencies of the third frequency band to create an inverted third frequency band; determining the frequency spectrum corresponds to an exhalation based on a slope value between amplitude distributions of the amplified first frequency band and amplitude distributions of at least a portion of the inverted third frequency band; and modifying an experience presented to a user of the device based on the exhalation. ### Claim 2 (depends on 1) The method of claim 1, further comprising: applying a second filter to the inverted third frequency band to create an isolated harmonics band; applying a second gain to the isolated harmonics band to create an amplified isolated harmonics band; and wherein determining the frequency spectrum corresponds to the exhalation further comprises determining the frequency spectrum corresponds to the exhalation based on the slope value between the amplitude distributions of the amplified first frequency band and amplitude distributions of the amplified isolated harmonics band. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the frequency spectrum corresponds to the exhalation further comprises determining the slope value for the amplitude distributions based on a moving average of the amplitude distributions. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the frequency spectrum corresponds to the exhalation further comprises: determining the frequency spectrum corresponds to the exhalation based on one of a positive slope value or a negative slope value. ### Claim 5 (depends on 1) The method of claim 1, wherein determining the frequency spectrum corresponds to the exhalation, further comprises: determining the frequency spectrum corresponds to the exhalation when the slope value exceeds a threshold value. ### Claim 6 (depends on 1) The method of claim 1, wherein determining the frequency spectrum of amplitude distributions for the one or more frequencies represented by the audio data further comprises: calculating, by the processor, at least one of a Discrete Time Fourier Transform (DTFT) or a Fast Fourier Transform (FFT) for the audio data to determine the frequency spectrum of amplitude distributions. ### Claim 7 (depends on 1) The method of claim 1, wherein the frequency spectrum of amplitude distributions for the one or more frequencies represented by the audio data, further comprises: applying a Fourier transform to the audio data to determine the frequency spectrum of amplitude distributions. ### Claim 8 (depends on 1) The method of claim 1, wherein the first frequency band has at least two subset of frequencies that include at least a target-subset of frequencies and an overflow subset of frequencies, and wherein applying the gain to the first set of frequencies comprises applying a first gain to the target-subset of frequencies, and applying an second gain to the overflow subset of frequencies. ### Claim 9 (depends on 1) The method of claim 1, wherein the input interface on the device includes a microphone, the method further comprising: converting sound from an environment proximate to the device into the audio data using the microphone. ### Claim 10 (depends on 1) The method of claim 1, wherein applying the filter to the second set of frequencies further comprises, applying a band pass filter to the frequency spectrum to null the second set of frequencies. ### Claim 11 (depends on 1) The method of claim 1, wherein modifying the experience presented to the user of the device further comprises adjusting content presented to the user. ### Claim 12 (depends on 1) The method of claim 1, wherein the device includes at least one of a wearable headset, an Augmented Reality (AR) headset, an Enhanced Reality (ER) headset, or a Virtual Reality (VR) headset. ### Claim 13 (depends on 1) The method of claim 1, further comprising: determining the frequency spectrum corresponds to an exhalation for a time period; and determining a rate of respiration based on the time period. ### Claim 14 A device for monitoring respiration, the device comprising: one or more input interfaces; a processor coupled to the input interfaces and adapted to execute one or more processes; and a memory operable to store instructions executable by the processor, wherein the instructions, when executed by the processor, are operable to: receive audio data representing sound detected by an input interface on a device; determine a frequency spectrum of amplitude distributions for one or more frequencies represented by the audio data; identify a first frequency band including a first set of frequencies associated with respiration, a second frequency band including a second set of frequencies associated with noise, and a third frequency band including a third set of frequencies associated with voice harmonics; apply a gain to the first set of frequencies to create an amplified first frequency band; apply a filter to the second set of frequencies to create a nulled second frequency band; invert the third set of frequencies of the third frequency band to create an inverted third frequency band; determine the frequency spectrum corresponds to an exhalation based on a slope value between amplitude distributions of the amplified first frequency band and at least a portion of amplitude distributions of the inverted third frequency band; and modify an experience presented to a user of the device based on the exhalation. ### Claim 15 (depends on 14) The device of claim 14, wherein the instructions, when executed by the processor, are further operable to: apply a second filter to the inverted third frequency band to create an isolated harmonics band; apply a second gain to the isolated harmonics band to create an amplified isolated harmonics band; and wherein the instructions to determine the frequency spectrum corresponds to the exhalation are further operable to determine the frequency spectrum corresponds to the exhalation based on the slope value between the amplitude distributions of the amplified first frequency band and amplitude distributions of the amplified isolated harmonics band. ### Claim 16 (depends on 14) The device of claim 14, wherein the instructions to determine the frequency spectrum corresponds to the exhalation are further operable to determine the slope value between the amplitude distributions based on a moving average of the amplitude distributions. ### Claim 17 (depends on 14) The device of claim 14, wherein the instructions to determine the frequency spectrum corresponds to the exhalation are further operable to: determine the frequency spectrum corresponds to the exhalation when the slope value exceeds a threshold value. ### Claim 18 A tangible, non-transitory, computer-readable media having instructions encoded thereon, the instructions, when executed by a processor, are operable to: receive audio data representing sound detected by an input interface on a device; determine a frequency spectrum of amplitude distributions for one or more frequencies represented by the audio data; identify a first frequency band including a first set of frequencies associated with respiration, a second frequency band including a second set of frequencies associated with noise, and a third frequency band including a third set of frequencies associated with voice harmonics; apply a gain to the first set of frequencies to create an amplified first frequency band; apply a filter to the second set of frequencies to create a nulled second frequency band; invert the third set of frequencies of the third frequency band to create an inverted third frequency band; determine the frequency spectrum corresponds to an exhalation based on a slope value between amplitude distributions of the amplified first frequency band and at least a portion of amplitude distributions of the inverted third frequency band; and modify an experience presented to a user of the device based on the exhalation. ### Claim 19 (depends on 18) The tangible, non-transitory, computer-readable media of claim 18, wherein the instructions, when executed by the processor, are further operable to: apply a second filter to the inverted third frequency band to create an isolated harmonics band; apply a second gain to the isolated harmonics band to create an amplified isolated harmonics band; and wherein the instructions to determine the frequency spectrum corresponds to the exhalation are further operable to determine the frequency spectrum corresponds to the exhalation based on the slope value between the amplitude distributions of the amplified first frequency band and the amplified isolated harmonics band. ### Claim 20 (depends on 18) The tangible, non-transitory, computer-readable media of claim 18, wherein the instructions to determine the frequency spectrum corresponds to the exhalation are further operable to: determine the frequency spectrum corresponds to the exhalation when the slope value exceeds a threshold value.