# US 2021/0241747 A1 · Systems and methods for on ear detection of headsets > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241747 A1 - Document ID: US20210241747A1 - Status: Published application - Kind: A1 - Application number: 16/777,016 - Filed: 2020-01-30 - Published: 2021-08-05 - Earliest claimed: 2020-01-30 - Assignees: Cirrus Logic International Semiconductor Ltd. - Applicants: Cirrus Logic International Semiconductor Ltd. - Inventors: Brenton STEELE - Web page: https://patentgrep.com/patent/US20210241747A1 ## CPC - G10K 11/17881: {the reference signal being an acoustic signal, e.g. recorded with a microphone} - H04R 1/1041: {Mechanical or electronic switches, or control elements (switches in general H01H)} - H04R 3/002: {Damping circuit arrangements for transducers, e.g. motional feedback circuits} - H04R 3/007: {Protection circuits for transducers} - G10K 2210/1081: Earphones, e.g. for telephones, ear protectors or headsets - G10K 2210/3028: Filtering, e.g. Kalman filters or special analogue or digital filters - G10K 2210/3226: Sensor details, e.g. for producing a reference or error signal - H04R 1/1016: {Earpieces of the intra-aural type} - H04R 2460/03: Aspects of the reduction of energy consumption in hearing devices - 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 - 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 Embodiments generally relate to a signal processing device for on ear detection for a headset. The device comprises a first microphone input for receiving a microphone signal from a first microphone, the first microphone being configured to be positioned inside an ear of a user when the user is wearing the headset; a second microphone input for receiving a microphone signal from a second microphone, the second microphone being configured to be positioned outside the ear of the user when the user is wearing the headset; and a processor. The processor is configured to receive microphone signals from each of the first microphone input and the second microphone input; pass the microphone signals through a first filter to remove low frequency components, producing first filtered microphone signals; combine the first filtered microphone signals to determine a first on ear status metric; pass the microphone signals through a second filter to remove high frequency components, producing second filtered microphone signals; combine the second filtered microphone signals to determine a second on ear status metric; and combine the first on ear status metric with the second on ear status metric to determine the on ear status of the headset. ## Claims ### Claim at position 1 -31. (canceled) ### Claim 32 A signal processing device for on ear detection for a headset, the device comprising: a first microphone input for receiving a microphone signal from a first microphone, the first microphone being configured to be positioned inside an ear of a user when the user is wearing the headset; a second microphone input for receiving a microphone signal from a second microphone, the second microphone being configured to be positioned outside the ear of the user when the user is wearing the headset; and a processor configured to: receive microphone signals from each of the first microphone input and the second microphone input; pass the microphone signals through a first filter to remove low frequency components, producing first filtered microphone signals; combine the first filtered microphone signals to determine a first on ear status metric; pass the microphone signals through a second filter to remove high frequency components, producing second filtered microphone signals; combine the second filtered microphone signals to determine a second on ear status metric; and combine the first on ear status metric with the second on ear status metric to determine the on ear status of the headset. ### Claim 33 (depends on 32) The signal processing device of claim 32, wherein the first filter is configured to filter the microphone signals to retain only frequencies that are likely to correlate to bone conducted speech of the user of the headset. ### Claim 34 (depends on 33) The signal processing device of claim 33, wherein the second filter is configured to filter the microphone signals to retain only frequencies that are likely to resonate within the ear of the user. ### Claim 35 (depends on 34) The signal processing device of claim 34, wherein the first filter and the second filter are band pass filters. ### Claim 36 (depends on 32) The signal processing device of claim 32, wherein combining the first filtered signals comprises subtracting the first filtered signal derived from the microphone signal received from the second microphone from the first filtered signal derived from the microphone signal received from the first microphone. ### Claim 37 (depends on 32) The signal processing device of claim 32, wherein combining the second filtered signals comprises subtracting the second filtered signal derived from the microphone signal received from the first microphone from the second filtered signal derived from the microphone signal received from the second microphone. ### Claim 38 (depends on 32) The signal processing device of claim 32, wherein combining the first on ear status metric with the second on ear status metric comprises adding the metrics together, and comparing the result with a predetermined threshold. ### Claim 39 A method of on ear detection for an earbud, the method comprising: receiving microphone signals from each of a first microphone and a second microphone, wherein the first microphone is configured to be positioned inside an ear of a user when the user is wearing the earbud and the second microphone is configured to be positioned outside the ear of the user when the user is wearing the earbud; passing the microphone signals through a first filter to remove low frequency components, producing first filtered microphone signals; combining the first filtered microphone signals to determine a first on ear status value; passing the microphone signals through a second filter to remove high frequency components, producing second filtered microphone signals; combining the second filtered microphone signals to determine a second on ear status value; and combining the first on ear status value with the second on ear status value to determine the on ear status of the headset. ### Claim 40 (depends on 39) The method of claim 39, wherein the first filter is configured to filter the microphone signals to retain only frequencies that are likely to correlate to bone conducted speech of the user of the headset. ### Claim 41 (depends on 40) The method of claim 40, wherein the second filter is configured to filter the microphone signals to retain only frequencies that are likely to resonate within the ear of the user. ### Claim 42 (depends on 41) The method of claim 41, wherein the first filter and the second filter are band pass filters. ### Claim 43 (depends on 39) The method of claim 39, wherein combining the first filtered signals comprises subtracting the first filtered signal derived from the microphone signal received from the second microphone from the first filtered signal derived from the microphone signal received from the first microphone. ### Claim 44 (depends on 39) The method of claim 39, wherein combining the second filtered signals comprises subtracting the second filtered signal derived from the microphone signal received from the first microphone from the second filtered signal derived from the microphone signal received from the second microphone. ### Claim 45 (depends on 39) The method of claim 39, wherein combining the first on ear status metric with the second on ear status metric comprises adding the metrics together to produce a passive OED metric, and comparing the passive OED metric with a predetermined threshold. ### Claim 46 (depends on 45) The method of claim 45, further comprising incrementing an on ear variable if the passive OED metric exceeds the threshold, and incrementing an off ear variable if the passive OED metric does not exceed the threshold. ### Claim 47 (depends on 46) The method of claim 46, further comprising determining that the status of the earbud is on ear if the on ear variable value is larger than a first predetermined threshold and the off ear variable value smaller than a second predetermined threshold; determining that the status of the earbud is off ear if the off ear variable value is larger than the first predetermined threshold and the on ear variable value smaller than the second predetermined threshold; and otherwise determining that the status of the earbud is unknown. ### Claim 48 (depends on 39) The method of claim 39, further comprising determining whether the microphone signals correspond to valid data, by comparing the power level of the microphone signals received from the second microphone exceed a predetermined threshold. ### Claim 49 (depends on 39) A non-transitory machine-readable medium storing instructions which, when executed by one or more processors, cause an electronic apparatus to perform the method of claim 39. ### Claim 50 (depends on 39) An apparatus, comprising processing circuitry and a non-transitory machine-readable which, when executed by the processing circuitry, cause the apparatus to perform the method of claim 39. ### Claim 51 (depends on 39) A system for on ear detection for an earbud, the system comprising a processor and a memory, the memory containing instructions executable by the processor and wherein the system is operative to perform the method of claim 39.