Robust open-ear ambient sound control with leak detection

Abstract

Embodiments of systems and methods for adaptive noise control for headphones, particularly open-ear headphones, are described herein. A leak detection module in an ambient sound control (ASC) circuit implements leak detection to determine a leakage pattern. Based on the determined leakage pattern, an ASC curve can be generated, selected, or modified for operation of the ASC circuit. A pilot tone, ambient noise, or audio playback can be used separately or in combination for leak detection. Experimental results show that embodiments of the adaptive ASC method can achieve improved performance compared to default ASC, particularly with a loose fit of headphones.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 076,901, filed on September 10, 2020, entitled “ROBUST OPEN-EARAMBIENT SOUND CONTROL WITH LEAKAGE DETECTION,” and named as such by Jianjun He and Vivek Nigam. The above patent document is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to leak detection and ambient sound control, and more particularly to leak detection and ambient sound control for open-ear headphones. Background Art

[0004] Noise cancelling headphones are widely used in various situations where active noise cancellation (ANC) can be used to reduce unwanted ambient sounds.

[0005] Most ANC headphones have a closed-ear form factor, with earcups that cover the user's ears to create a seal or closed cavity. ANC headphones may use microphones on the outside of the earcups (also called feed-forward microphones), feed-back microphones on the inside of the earcups, or a combination of both feed-forward and feed-back microphones.

[0006] Although closed-ear ANC headphones can reduce or eliminate unwanted ambient noise, they can be uncomfortable to wear for extended periods of time. On the other hand, open-ear headphones are relatively lightweight and therefore cause less discomfort and fatigue, making them more convenient for long-term wear. However, due to the lack of a sealed cavity between the earbud and the eardrum for ANC implementation, open-ear headphones may face more challenges in ANC. For a sealed form factor like the AirPods Pro (where silicon contacts create a sealed chamber between the form factor and the eardrum), ANC may be more effective. For open-ear headphones or for closed-ear headphones with a loose fit, the impact of ambient noise may vary and the degree of audio signal leakage may also change significantly. In addition, the response of the speakers in the headphones varies greatly depending on the fit conditions. This problem makes effective ANC implementation challenging.

[0007] Therefore, it would be desirable to have systems and methods for robust leakage detection and adaptive ambient sound control for open-ear applications. Summary of the Invention

[0008] On the one hand, a method for adaptive noise control in an earphone is provided, the method comprising: performing leakage detection using a leakage detection module to determine a leakage pattern of the earphone, the leakage detection involving at least one of a first microphone and a second microphone, the first microphone and the second microphone being integrated with a speaker within the earphone, the leakage detection being associated with leakage of ambient sound through at least an ambient leakage path disposed between a portion of an ear canal and a portion of the earphone; outputting a set of operating parameter ranges for components in an ambient sound control (ASC) circuit based on the determined leakage pattern using an ambient sound control (ASC) curve selection and modification module, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns; and generating a speaker output using the ASC circuit operating within the set of operating parameter ranges for playback by the speaker.

[0009] On the other hand, an earphone is provided, comprising: a speaker; a first microphone and a second microphone, the first microphone and the second microphone being integrated with the speaker within the earphone; a leakage detection module, the leakage detection module performing leakage detection to determine a leakage pattern of the earphone, the leakage detection involving at least one of the first microphone and the second microphone, the leakage detection being associated with leakage of ambient sound through at least an ambient leakage path disposed between a portion of the ear canal and a portion of the earphone, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns; an ambient sound control (ASC) curve selection and modification module, the module outputting a set of operating parameter ranges for components in the ASC circuit based on the determined leakage pattern; and the ASC circuit operating within the set of operating parameter ranges to generate a speaker output for playback by the speaker.

[0010] On the other hand, one or more non-transitory computer-readable media are provided, comprising one or more instruction sequences that, when executed by at least one processor, cause execution of adaptive noise control steps for an earphone integrated with a first microphone, a second microphone, and a speaker, the steps comprising: performing leakage detection using a leakage detection module to determine a leakage pattern of the earphone, the leakage detection involving at least one of the first microphone and the second microphone, the leakage detection being associated with leakage of ambient sound through at least an ambient leakage path disposed between a portion of the ear canal and a portion of the earphone; and outputting a set of operating parameter ranges for components in an ambient sound control (ASC) circuit within the earphone based on the determined leakage pattern using an ambient sound control (ASC) curve selection and modification module so that the ASC circuit operates within the set of operating parameter ranges, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Reference will now be made to the exemplary embodiments of the present invention which are shown in the accompanying drawings. These drawings are intended to be illustrative, not restrictive. Although the present invention is generally described in the context of these embodiments, this is not intended to limit the scope of the invention to the specific features of the depicted or described embodiments.

[0012] Figure 1 A schematic diagram of open-ear headphones is depicted in accordance with one or more embodiments of the present invention.

[0013] Figure 2 Depicted is a block diagram of an adaptive ambient sound control (ASC) circuit in accordance with one or more embodiments of the present invention.

[0014] Figure 3 The process of adaptive ASC based on leak detection according to one or more embodiments of the present invention is graphically depicted.

[0015] Figure 4 The process of adaptive ASC based on performance estimation according to one or more embodiments of the present invention is graphically depicted.

[0016] Figure 5 Depicted is a schematic diagram of leak detection and ASC update using pilot tones in accordance with one or more embodiments of the present invention.

[0017] Figure 6 A process for leak detection and ASC update using pilot tones according to one or more embodiments of the present invention is graphically depicted.

[0018] Figure 7 Depicted is a schematic diagram of leak detection and ASC update using ambient noise in accordance with one or more embodiments of the present invention.

[0019] Figure 8 Depicted is a schematic diagram of leak detection and ASC updating using audio playback in accordance with one or more embodiments of the present invention.

[0020] Figure 9 Depicted is an ANC performance comparison between a default ASC and an adaptive ASC embodiment under various coordinations according to one or more embodiments of the present invention.

[0021] Those skilled in the art will recognize that various embodiments and examples of the present invention can be practiced according to the description.All such embodiments and examples are intended to be included within the scope of the present invention. DETAILED DESCRIPTION

[0022] In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. However, the present invention can be put into practice without some or all of these details. The embodiments of the present invention described below can be incorporated into a plurality of different electronic components, circuits, equipment and systems. The structures and equipment shown in the block diagrams are demonstrations of exemplary embodiments of the present invention and are not used as pretexts for obscuring the broad teachings of the present invention. The connection between the components in the figure is not intended to be limited to direct connection. Instead, the connection between the components can be modified, reformatted or otherwise changed by intermediate components.

[0023] When this specification refers to "one embodiment" or to "an embodiment," it is intended to mean that a particular feature, structure, characteristic, or function described in connection with the embodiment in question is included in at least one contemplated embodiment of the present invention. Thus, the appearances of the phrase "in one embodiment" in various places in this specification do not constitute multiple references to a single embodiment of the present invention.

[0024] Furthermore, the connections between components or systems within the drawings are not intended to be limited to direct connections. Rather, data or signals between these components may be modified, reformatted, or otherwise altered by intermediate components. Moreover, additional or fewer connections may be used. It should also be noted that the terms "coupled," "connected," or "communicatively coupled" should be understood to include direct connections, indirect connections through one or more intermediate devices, and wireless connections.

[0025] Those skilled in the art will recognize that: (1) certain steps may be performed optionally; (2) the steps may not be limited to the specific order set forth herein; (3) certain steps may be performed in a different order; and (4) certain steps may be performed simultaneously.

[0026] Figure 1 is a schematic diagram of an open-ear headphone 110. Ambient noise can be Figure 1 The ambient leakage path 125 indicated by the curved arrow leaks into the ear canal 120. This ambient leakage into the ear canal presents additional challenges for completely eliminating ambient noise. The performance of the headphone speakers may be adversely affected by the leakage path. For example, the speaker's response to the audio playback delivered to it - and in particular, the user's perception of the sound produced by the speaker - may be impaired. In some instances, the performance degradation may affect different frequencies to different degrees. For example, the speaker's response may be affected more at low frequencies and less at high frequencies. This may result in spectral distortion of the audio playback.

[0027] Although Figure 1 The leakage path 125 shown in FIG is the path between the earphone and the ear canal of the earphone user, but the leakage path may be adapted to other paths that allow ambient sound to leak into the ear canal. For example, an open-ear earphone may have a tight fit that prevents the earphone from falling out when the user moves, but it may have one or more built-in vents that allow ambient sound to leak into the ear canal. Those skilled in the art will also understand that Figure 1 The diagram shown in FIG2 may also be applicable to some closed-ear headphones. When a user wears the closed-ear headphones incorrectly or when the ear cups of the closed-ear headphones have defects, leakage channels may occur, thereby affecting the noise cancellation performance.

[0028] Because each user has a unique ear anatomy, the geometry of the leakage path (especially for open-ear headphones) can vary from user to user (and even from ear to ear for a specific user). Furthermore, when the user moves or the ambient noise level changes significantly, the noise cancellation implementation may need to be adjusted or updated. Therefore, a one-size-fits-all ANC curve may not deliver top-quality noise cancellation performance.

[0029] One or more embodiments described in the present disclosure relate to adaptively outputting an ambient sound control (ASC) curve for operation of an ASC circuit based on a leakage pattern determined based on leak detection. In one or more embodiments, the ASC circuit can function to reduce ambient noise. In one or more embodiments, the ASC circuit can be a circuit for ANC. In one or more embodiments, the ASC circuit can be a circuit in a personal sound amplification product (PSAP) for hearing enhancement. An embodiment of the ASC can relate to selectively controlling the level, frequency, or spectrum of one or more sound sources in the surrounding environment, wherein the control can be an operation of reducing, maintaining, increasing, or a combination thereof to achieve desired performance.

[0030] For ANC in headphones with an open-ear configuration, the ASC circuit may need to be tuned to have a wider bandwidth (e.g., >700Hz) since a loose fit results in poorer passive attenuation. The implementation curves of the ASC circuit may need to be continuously updated based on the degree of leakage detected. The open-ear configuration creates a non-sealed housing in which a single ASC curve may not provide consistent noise cancellation performance. In addition, different wearing styles may result in different amounts of ambient noise leakage, and therefore different ASC curves may be required to provide consistent ASC performance. Therefore, an adaptive ASC with a set of ASC curves is needed. At least due to the continuous leakage detection and curve updating, the power consumption of the open-ear headphones may increase, and therefore, the ASC implementation may need to be optimized.

[0031] In one or more embodiments, the ASC circuit may include one or more converters for analog-to-digital or digital-to-analog conversion, one or more filters (e.g., low-pass filters, high-pass filters, band-pass filters, and / or band-stop filters), and / or one or more gain / volume stages operating at various frequency bands. Each of the filters or gain / volume stages may have its operating parameters, such as cutoff frequency, gain, bandwidth, etc. In one or more embodiments, an ASC curve may refer to a set of operating parameter levels, limits, or ranges for components (e.g., filters, gain / volume stages, etc.) in the ASC circuit.

[0032] In one or more embodiments, it may be desirable for the ASC circuit to have different curves to respond to different ambient environments. For example, in a quiet environment, it may be preferable to have the ASC circuit operate with a "soft" curve with low amplification or a small parameter range, so that the ASC circuit only needs to search for noise compensation within a narrow parameter range, and thus can achieve lower power consumption. In a noisy environment with loud low-frequency noise, it may be desirable to have the ASC circuit operate with a more drastic curve with a larger parameter range for low-frequency filters or gain / volume levels, but maintain a relatively low parameter range for high-frequency filters or gain / volume levels, so that the ASC circuit searches for low-frequency noise compensation within a wider parameter range, but maintains a low operating parameter range for high-frequency noise components. This adaptive ASC curve setting can not only achieve a fast dynamic response to noise compensation, but also achieve noise compensation with lower power consumption.

[0033] Figure 2 is a block diagram of an ambient sound control circuit according to one or more embodiments of the present invention. An ASC circuit 210 is coupled to a first microphone 202, a second microphone 204, and a speaker 230. In one or more embodiments, the first microphone 202 is a feed-forward microphone (hereinafter referred to as "FFM" or "FF mic") located outside the earphone 110, and the second microphone 204 is a feedback microphone (hereinafter referred to as "FBM" or "FB mic") located inside the earphone 110 and near the speaker 230. The ASC circuit 210 receives a microphone signal 203 from the FF mic 202, a microphone signal 205 from the FB mic 204, and a playback signal 206, and generates an output signal 220 that cancels the ambient noise for playback by the speaker 230.

[0034] In one or more embodiments, the ASC circuit 210 may include one or more processors 212, one or more memory devices 213, one or more converters 214 for analog-to-digital or digital-to-analog conversion, an interface 215 for data communication, and a power supply 216. The processor 212 may be a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a media control unit (MCU), a system-on-chip processor (SoC), or some other type of processor. The memory device 213 may include random access memory (RAM), read-only memory (ROM), a storage device, or any other medium capable of storing electronic instructions or information in a processor-readable form. In one or more embodiments, the ASC circuit 210 may include a leakage detection module 217 for performing leakage detection. In one or more embodiments, the ASC circuit 210 may further include a performance estimation module 218 for performing playback and / or ASC performance estimation. The results of the leakage detection and / or performance estimation may be used as a reference for determining the operating curve of the ASC circuit. The leakage detection module 217 and the performance estimation module 218 may be software / hardware components executed by the processor(s) 212 using instructions stored in the memory 213. In some implementations, the leak detection module 217 can be activated when the headset is in ASC mode (eg, ANC mode without any audio playback) or in playback mode, or when both ASC and playback are activated.

[0035] In one or more embodiments, the one or more converters 214 may include an analog-to-digital converter for converting the microphone signal 203 from the FF mic 202 and the microphone signal 205 from the FB mic 204 into digital signals for processing.

[0036] In one or more embodiments, the ASC circuit 210 may include one or more filters (e.g., a low-pass filter, a high-pass filter, a band-pass filter, and / or a band-stop filter) for performing one or more filtering operations. The one or more filters may be digital filters that perform desired mathematical operations on digital signals using instructions executable on one or more processors 212. Filter parameters (e.g., filter coefficients) may be stored in the memory 213.

[0037] In one or more embodiments, the playback signal 206 is an analog signal, and the interface 215 may be a wired interface for receiving the playback signal 206 and other control signals (e.g., volume up / down, etc.). In one or more embodiments, the interface 215 may be a wireless interface (e.g., a Bluetooth interface) for wirelessly receiving the playback signal 206 and other control signals.

[0038] In one or more embodiments, the ASC circuit 210 can be integrated into headphones (or earbuds, earphones, in-ear headphones, etc.) together with the FF mic 202, the FB mic 204, and the speaker 230. In one or more embodiments, the ASC circuit 210 can be a separate component that is coupled to the FF mic 202, the FB mic 204, and the speaker 230 in the headphones in a wired or wireless manner.

[0039] As used herein, the term "headphones" refers to a device that delivers audio content through a compact environment that surrounds at least a portion of a user's ear, such as the ear canal or outer ear, rather than through the ambient air as in the case of an amplifier such as the speakers of a home sound system or the built-in speakers of a smartphone. Thus, headphones can be in the form of ear-hook headphones, earbuds, or in-ear headphones, etc. As used herein, the plural term "headphones" means devices that are intended for both single and double ears. As used herein, the term "audio" means sounds within the user's hearing range. As used herein, the term "sound" means any air pressure wave within or outside the user's hearing range. For example, a wave with a frequency of 100 Hz may be referred to as sound or audio in the present disclosure, while a wave with a frequency of 15 Hz (i.e., below the human hearing range (typically 20 Hz to 20 kHz)) may be referred to as sound.

[0040] Figure 3 The process of adaptive ASC based on leak detection according to one or more embodiments of the present invention is graphically depicted. In step 310, the leak detection module performs leak detection to generate a leak pattern signal based on one or more inputs from the FF mic 202, the FB mic 204, or the playback signal 206. The leak pattern signal may indicate the degree of leakage and / or the intensity of ambient noise and the spectral distribution inside the ear canal. Various methods may be used for leak detection. Figures 5 to 8Some detailed embodiments are described, such as using pilot tones in audio playback, ambient noise analysis, and audio playback analysis. In step 320, an ASC curve selection and modification module outputs an ASC curve based on the leakage pattern signal. The ASC curve can be selected from a plurality of ASC curves, newly generated using the leakage pattern signal, or modified from an existing ASC curve. In one or more embodiments, the ASC curve selection and modification module can be a software module including instructions stored in a memory of the ASC circuit. In one or more embodiments, the ASC curve selection and modification module can be external to the ASC circuit and communicatively coupled to receive the leakage pattern signal for ASC curve selection, generation, or modification. For example, the ASC curve selection and modification module can be located within an electronic device (e.g., a music player, smartphone, etc.) that generates the audio playback signal. In one or more embodiments, the ASC curve selection and modification module can include a database that correlates various leakage patterns with various ASC curves. In one or more embodiments, a correlation can be a 1:1, N:1, or 1:N relationship (N is an integer greater than 1) between a leakage pattern and an ASC curve. These correlations can be predefined and may or may not be modified. The ASC curve selection and modification module can compare the leakage pattern signal received from the leak detection module with the leakage patterns in the database. If a match is identified, the corresponding ASC curve is selected and output as the ASC curve. If a match is not identified, a new ASC curve can be generated and output as the ASC curve. Alternatively, an existing ASC curve with a high degree of match can be modified and output as the ASC curve.

[0041] In step 330, the ASC circuit applies the ASC curve output to generate the speaker output 220 for playback by the speaker 230. Depending on the operating mode of the headset (e.g., quiet mode or playback mode), the speaker output may or may not include the playback audio signal. In one or more embodiments, steps 310 to 330 may be repeated at predetermined time intervals.

[0042] Figure 4 The process of adaptive ASC based on performance estimation according to one or more embodiments of the present invention is graphically depicted. Instead of being driven by leakage detection, ASC based on performance estimation can be driven by audio playback and / or ASC performance optimization. For implementations of adaptive ASC based on performance estimation, it may be desirable to have overall minimal distortion or minimized distortion for certain frequency bands of the played back audio rather than having minimal ambient noise. With adaptive ASC based on leakage detection, when the ASC circuit adds a compensation signal to the audio playback signal to minimize ambient noise, the sound from the speaker may be distorted from the original audio playback. Therefore, the user's audio experience may be negatively impacted.

[0043] In step 410, the performance estimation module performs a performance estimation to generate an indicator signal based on one or more inputs from the FF mic 202, the FB mic 204, or the playback signal 206. The indicator signal may indicate the level of audio playback and / or the ASC performance. In one or more embodiments, the indicator signal may indicate the degree of playback distortion and / or the distortion spectrum distribution under the current ambient noise. In one or more embodiments, the performance estimation may include a comparison between the playback signal 206 and the input from the FB mic 204. In one or more embodiments, the indicator signal may indicate the ambient noise level and / or the noise spectrum distribution to indicate the performance of the ASC circuit.

[0044] At step 420, the ASC curve selection and modification module outputs an ASC curve based on the indicator signal. Similar to step 320, the ASC curve can be selected from a plurality of ASC curves from a database that correlates various indicator levels with various ASC curves, newly generated using the leakage mode signal, or modified from an existing ASC curve. These correlations can be predefined and may or may not be modified. The ASC curve selection and modification module can compare the indicator signal received from the performance estimation module with the indicator signals in the database. If a match is identified, the corresponding ASC curve is selected as the ASC curve output. If a match is not identified, a new ASC curve can be newly generated as the ASC curve output. Alternatively, an existing ASC curve with a high degree of match can be modified to be the ASC curve output.

[0045] In step 430, the ASC circuit applies the ASC curve output to generate the speaker output 220 for playback by the speaker 230. In one or more embodiments, steps 410 to 430 may be repeated at predetermined time intervals.

[0046] Figure 5A schematic diagram of using a pilot tone for leak detection and ASC update according to one or more embodiments of the present invention is depicted. In some embodiments, the frequency of the pilot tone can be at a value below the hearing range (e.g., below 20 Hz). Such an arrangement can have the benefit of not disturbing the user of the headset. Although it is still technically possible to use a pilot tone with a frequency within the hearing range, this approach may not be popular with users because it may cause interference with the playback audio. In some embodiments, the pilot tone can include several discrete or quasi-discrete frequencies. In some embodiments, the pilot tone can be a narrowband signal or include two or more narrowband signals. In one or more embodiments, the use of the pilot tone can be implemented in the presence or absence of an audio playback signal. For example, a user may just want to perform noise cancellation to get some quiet time, rather than some audio playback. In such an instance, in order not to interfere with the user's desired silence, the pilot tone can be used without involving audio playback (e.g., using the headset only in noise cancellation mode). Alternatively, the ASC circuit can insert (510) a pilot tone with a frequency below the lower threshold of the human hearing range into the audio playback.

[0047] After the pilot tone is inserted into the audio playback for playback by the speaker 230, the response signal of the FBM and / or FFM to the pilot tone is analyzed (520) to determine the degree of leakage. In one or more embodiments, the analysis may include a power analysis of the response corresponding to the frequency of the pilot tone. The ASC curve and the audio playback settings may then be updated (530) based on the determined degree of leakage.

[0048] Figure 6 The process of leak detection and ASC update using a pilot tone according to one or more embodiments of the present invention is graphically depicted. In step 605, a pilot tone with a predetermined amplitude (e.g., -40 dB) is played through the headphone's speaker. The pilot tone has a frequency below the audible range (e.g., below 20 Hz), so the user may not even notice it. In one or more embodiments, the pilot tone is added to the audio playback or played as a standalone pilot tone through the speaker. In response to the played pilot tone, the FB mic outputs an FB mic signal. In step 610, the amplitude of the FB mic signal at the pilot tone's frequency is obtained. In step 615, the amplitude is averaged over each short frame (e.g., 0 to 1 second) to obtain a plurality of average amplitudes. In step 620, the plurality of average amplitudes are classified into various leakage levels based on predetermined classifications. In one or more embodiments, the predetermined classifications are stored in the ASC circuit's memory as a calibration reference to determine the leakage level and / or required modification of the ASC / playback signal for a specific fit detected using the pilot tone.

[0049] In step 625, the leakage level with the highest classification percentage within a predetermined time interval (e.g., a time interval between 1 second and 1 minute) is calculated and compared to one or more thresholds. At step 630, a leakage pattern is identified based on these comparisons. In step 635, an ASC curve is determined or updated based on the identified leakage pattern.

[0050] It should be noted that Figure 6 The steps for pilot signal-based leakage detection shown in the accompanying drawings are exemplary and are performed using one or more specific embodiments under specific parameters and / or conditions; therefore, these settings and / or processes should not be used to limit the scope of the disclosure of the current patent document.

[0051] Figure 7 A schematic diagram of leak detection and ASC update using ambient noise according to one or more embodiments of the present invention is depicted. Figure 7 As shown in FIG, the leakage detection module can perform leakage detection and compensation by detecting ambient noise passing through the FFM and FBM. The noise detected by the FFM located near the outer surface of the earphone can represent the intensity of the ambient noise in the current user's surrounding environment. The ambient noise can enter the user's ear canal, including through the leakage channel. In one or more embodiments, Figure 5 The leak detection shown in can be implemented during regular audio playback. In such an embodiment, the leak detection module may need to separate the audio playback from the ambient noise detected by the FBM and / or FFM in the total audio signal. In one or more embodiments, in order not to skew the detection of the ambient noise, the speakers in the earphones can be muted during the time when the leak detection is implemented using the ambient noise. Once the ambient noise is isolated in the total audio signal or it is recorded, the leak detection module can analyze (710) the power ratio between the ambient noise detected by the FBM inside the ear canal and the ambient noise detected by the FFM over a certain frequency range (e.g., the power ratio in the high audio frequency band) to determine the degree of leakage or leakage pattern. In one or more embodiments, because the source of the ambient noise is located outside the earphone, the ratio R of the ambient noise intensity (or amplitude) of the ambient noise detected by the FFM to the ambient noise intensity (or amplitude) of the ambient noise detected by the FBM is greater than or equal to the power ratio R of the ambient noise detected by the FBM. i (For multiple frequencies f i) may be greater than 1, and in some cases may be much greater than 1. During the analysis of intensity, the leakage detection module may take into account that a certain amount of ambient noise will enter the ear canal - through the user's skin, cartilage and bone - rather than through the leakage channel. Therefore, the leakage detection module may discount some of the data provided by the FBM and only consider the portion of the noise in the ear canal that may be attributable to the leakage channel. The discounting may be performed by reducing the intensity (or amplitude) of the ambient noise (as detected by the FBM) by a discount factor. These discount factors may be determined at the time of (or before) manufacture of the headset and stored in the memory of the ASC circuit. Based on the determined degree of leakage, the ASC curve and audio playback settings may be updated (720). In one or more embodiments, the ambient noise detection may be combined with Figure 5 The pilot tone detection shown in FIG is combined to increase the overall reliability of leakage detection and compensation.

[0052] Figure 8 A schematic diagram of leak detection and ASC update using audio playback according to one or more embodiments of the present invention is depicted. When a user is operating headphones for audio playback, the audio playback sound is output from the headphone speaker (810) and picked up by the FBM and FFM. The ASC circuit can analyze (820) the microphone signals from the FBM and FFM to determine the degree of leakage or the leakage pattern. Based on the determined degree of leakage or pattern, the ASC curve and audio playback settings can be updated (830). In one or more embodiments, the audio playback-based leak detection method can be combined with Figure 5 The pilot tone based leakage detection method shown in Figure 7 In one embodiment, the present invention combines the leak detection based on ambient noise shown in the figure to increase the overall reliability of leak detection and compensation. Because audio playback typically has a wide range of audio frequencies, the leak detection method based on audio playback may be superior to the leak detection method based on pilot tone, because the pilot tone may be limited to infrasonic frequencies and therefore may not accurately reflect leaks within the audio frequency range (e.g., 20 Hz to 20 kHz). The presence of audio frequencies in the audio playback can improve the accuracy of leak detection. In one or more embodiments, leak detection can be performed for multiple frequencies to determine the leakage ratio of multiple frequencies. On the other hand, the spectral content of audio playback may have significant differences, and enhancing the audio playback-based leak detection with the pilot tone-based leak detection can improve the overall reliability of leak detection and compensation.

[0053] The following describes some experimental comparison results. It should be noted that these experiments and results are provided in an illustrative manner and are performed under specific conditions using one or more specific embodiments; therefore, these experiments and their results should not be used to limit the scope of disclosure of the current patent document.

[0054] Figure 9 Depicted is a comparison of ANC performance between default ASC and adaptive ASC embodiments for tight fit, medium fit, and loose fit according to one or more embodiments of the present invention. Lines 902, 904, and 906 refer to the power spectra (in dB) of the audio signal measured at the feedback microphone of a headset with default ASC for tight fit, medium fit, and loose fit, respectively. Lines 912, 914, and 915 refer to the power spectra (in dB) of the audio signal measured at the feedback microphone of the same headset using adaptive ASC for tight fit, medium fit, and loose fit, respectively. It can be seen that the default ASC works well only for a tight fit. From Figure 9 It can also be clearly seen that under medium or loose headphone fit, Adaptive ASC has improved performance compared to Default ASC. Figure 9 The experiments in [1] used audio signals measured at the feedback microphone of a headset, but other types of microphones inside the ear can also be used to capture the in-ear sound pressure level (SPL) for evaluation and testing purposes.

[0055] The foregoing description of the present invention has been described for the purposes of clarity and understanding. It will be understood by those skilled in the art that the foregoing examples and embodiments are illustrative and not limiting of the scope of the present disclosure. It is intended that all permutations, enhancements, equivalents, combinations, and improvements thereto that would be apparent to one skilled in the art after reading this specification and studying the drawings are included within the true spirit and scope of the present disclosure. It should also be noted that the elements of any claim may be arranged in various ways, including having a variety of dependencies, configurations, and combinations.

Claims

1. A method for adaptive noise control in headphones, the method comprising: performing a leak detection, using a leak detection module, to determine a leakage pattern of the earphone, the leak detection involving at least one of a first microphone and a second microphone integrated with a speaker within the earphone, the leak detection being related to leakage of ambient sound through at least an ambient leakage path disposed between a portion of an ear canal and a portion of the earphone; outputting, using an ambient sound control (ASC) curve selection and modification module, a set of operating parameter ranges for components in an ASC circuit based on the determined leakage pattern, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns; as well as A speaker output is generated using the ASC circuit operating within the set of operating parameters for playback by the speaker.

2. The method according to claim 1, wherein The ambient leakage path is created due to the open-ear form factor or loose fit of the earphone.

3. The method according to claim 1, wherein The ASC circuit is a circuit for active noise cancellation.

4. The method according to claim 1, wherein The set of operating parameter ranges is defined as an ASC curve selected based on the determined leakage pattern from a plurality of ASC curves from a database that correlates various leakage patterns with various ASC curves.

5. The method according to claim 1, wherein The set of operating parameter ranges is defined as a newly generated ASC curve based on the determined leakage pattern.

6. The method of claim 1, wherein: The set of operating parameter ranges is defined as an ASC curve modified from an existing ASC curve.

7. The method of claim 1, wherein: The first microphone is a feedforward microphone located outside the earphone, and the second microphone is a feedback microphone placed inside the earphone.

8. The method of claim 7, wherein: Implementing leak detection includes: A power ratio between ambient noise detected by the feedback microphone and ambient noise detected by the feedforward microphone is analyzed to generate the leakage pattern.

9. The method of claim 7, wherein: Implementing leak detection includes: using the speaker to play audio playback; and Microphone signals from the feedback microphone and the feedforward microphone are analyzed to determine the leakage pattern.

10. The method of claim 7, wherein: Implementing leak detection includes: inserting a pilot tone having a predetermined frequency for playback by the speaker; and A microphone signal from the feedback microphone is analyzed to determine the leakage pattern.

11. A headset comprising: speaker; a first microphone and a second microphone, wherein the first microphone and the second microphone are integrated with the speaker in the headset; a leak detection module that performs a leak detection to determine a leakage pattern of the earphone, the leak detection involving at least one of the first microphone and the second microphone, the leak detection being related to leakage of ambient sound through at least an ambient leakage path disposed between a portion of the ear canal and a portion of the earphone, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns; an ambient sound control (ASC) curve selection and modification module that outputs a set of operating parameter ranges for components in the ASC circuit based on the determined leakage pattern; as well as The ASC circuit operates within the set of operating parameters to generate a speaker output for playback by the speaker.

12. The headset according to claim 11, wherein The first microphone is a feedforward microphone located outside the earphone, and the second microphone is a feedback microphone placed inside the earphone.

13. The headset according to claim 11, wherein The ASC circuit is a circuit for active noise cancellation.

14. The headset according to claim 11, wherein The set of operating parameter ranges is defined as an ASC curve selected based on the determined leakage pattern from a plurality of ASC curves from a database that correlates various leakage patterns with various ASC curves.

15. The headset according to claim 11, wherein The set of operating parameter ranges is defined as a newly generated ASC curve based on the determined leakage pattern.

16. The headset according to claim 11, wherein The set of operating parameter ranges is defined as an ASC curve modified from an existing ASC curve.

17. One or more non-transitory computer-readable media comprising one or more sequences of instructions that, when executed by at least one processor, cause steps of adaptive noise control for headphones integrated with a first microphone, a second microphone, and a speaker to be performed, the steps comprising: performing a leak detection using a leak detection module to determine a leakage pattern of the earphone, the leak detection involving at least one of the first microphone and the second microphone, the leak detection being related to leakage of ambient sound through at least an ambient leakage path disposed between a portion of the ear canal and a portion of the earphone; and An ambient sound control (ASC) curve selection and modification module is used to output a set of operating parameter ranges for components in an ASC circuit within the earphone based on the determined leakage pattern so that the ASC circuit operates within the set of operating parameter ranges, wherein the ASC circuit has different sets of operating parameter ranges corresponding to different leakage patterns.

18. The one or more non-transitory computer-readable media of claim 17, wherein: The set of operating parameter ranges is defined as an ASC curve selected based on the determined leakage pattern from a plurality of ASC curves from a database that correlates various leakage patterns with various ASC curves.

19. The one or more non-transitory computer-readable media of claim 17, wherein: The set of operating parameter ranges is defined as a newly generated ASC curve based on the determined leakage pattern.

20. The one or more non-transitory computer-readable media of claim 17, wherein: The set of operating parameter ranges is defined as an ASC curve modified from an existing ASC curve.

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