Personal protective equipment communication systems and methods

Abstract

A hearing protection device is presented that includes a microphone, a speaker, processing circuitry and memory. When actuated, the processing circuitry is configured to: receive a sound signal, analyze the sound signal, based on the analysis, apply a gain adjustment to the sound signal, and communicate the adjusted sound signal. The hearing protection device is configured to operate in a full-duplex mode and in a half-duplex mode.

Description

PERSONAL PROTECTIVE EQUIPMENT COMMUNICATION SYSTEMS AND METHODSBACKGROUND

[0001] Articles of personal protective equipment (PPE) are worn by workers in need of protection from dangerous environment or working conditions. Some examples include hearing protection equipment, fall protection equipment, respirators, face masks and gloves. Many PPE include communication components that can transmit audio or data signals through wired or wireless connections.SUMMARY

[0002] A hearing protection device is presented that includes a microphone, a speaker, processing circuitry and memory. When actuated, the processing circuitry is configured to: receive a sound signal, analyze the sound signal, based on the analysis, apply a gain adjustment to the sound signal, and communicate the adjusted sound signal. The hearing protection device is configured to operate in a full-duplex mode and in a half-duplex mode.

[0003] The above Summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. Further features and advantages are disclosed in the embodiments that follow. The Drawings and the Detailed Description that follow more particularly exemplify certain embodiments using the principles disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIGS. 1A-1B illustrate example hearing protection devices in which systems and methods herein may be useful.

[0005] FIG. 2 illustrates a communication in accordance with embodiments herein.

[0006] FIGS. 3A-3B illustrate examples of adaptive gain reduction in accordance with embodiments herein.

[0007] FIGS. 4A-4B illustrate examples of sound processing systems for hearing protection devices.

[0008] FIG. 5 illustrates a method of adjusting an applied gain for a hearing protection device in accordance with embodiments herein.

[0009] FIG. 6 illustrates a personal protection device in accordance with embodiments herein.

[0010] FIG. 7 is a block diagram of a computing environment that can be used in embodiments shown in previous Figures.

[0011] FIGS. 8-9 illustrate example applications of gain adjustment algorithms in accordance with embodiments herein.DETAILED DESCRIPTION

[0012] Noisy environments, such as worksites, airfields, and the like, may include noise sources that have the potential to damage the hearing of a person. A person operating in a noisy environment may experience hearing loss from acute acoustic trauma or gradually developing noise-induced hearing loss. Acute acoustic trauma may cause hearing loss from a one-time exposure to an excessive noise level, whereas gradually developing noise-induced hearing loss may result from exposure to unsafe noise levels over an extended period of time.

[0013] To prevent hearing damage, a person operating in noisy environment may wear hearing protection. Active hearing protection may include earmuffs that permit certain types of noise to pass through to a person by electronically reducing decibels or filtering out frequencies.

[0014] “Active hearing protection,” as used herein, includes one or more microphones that receive ambient sound from a user’s surroundings and uses one or more speakers to play it back at a safe decibel level. Active hearing protection devices use electronic circuitry to pick up ambient sound through the microphone and convert them to safe levels before playing it back to the user through a speaker. Additionally, active hearing protection may filter out undesired sound content, for example actively reducing the sound of a gunshot while providing human speech at substantially unchanged levels. However, while some embodiments of the present invention expressly contemplate units with active hearing protection, it is expressly contemplated that passive hearing protection units are included in other embodiments.

[0015] First, a sound signal is received by a microphone in an active hearing protection unit. The received sound signal is converted to an electronic signal for processing. After processing the sound signal such that all frequencies are at safe levels, the sound signal is reproduced and played back to a user through a speaker.

[0016] Some active hearing protection units are level dependent, such that an electronic circuit adapts the sound pressure level. Level dependent hearing protection units help to filter out impulse noises, such as gunshots from surrounding noises, and / or continuously adapt all ambient sound received to an appropriate level before it is reproduced to a user. Active hearing protection units, specifically level dependent active hearing protection units, may facilitate communication in noisy environments, or environments where noise levels can vary significantly, or where high impulse sounds may cause hearing damage.

[0017] Hearing protection units with active hearing protection can also receive digital signals from a source and provide them through the speakers inside the active hearing protection unit. For example, existing Bluetooth®-enabled headsets can stream audio, music, and play audio from a cell phone call. Existing headsets with push-to-talk technology can also, with the push of a button by the operator, send out a push-to-talk command to a mobile communications unit.

[0018] FIG. 1 illustrates a personal protective device in which embodiments of the present invention are useful. Personal protection device 100 may be enabled to communicate wirelessly using any suitable protocol such as, but not limited to, Bluetooth®, Bluetooth® SMART®, WiFi, Zigbee, Z- Wave, 6L0WPAN, cellular, etc. Acoustic headset 100 may provide for both digital and analog two- way communications using components that are integrated within auditory cups of the acoustic headset.

[0019] FIG. 1A is a diagram illustrating an example protective headset 100 that includes digital and analog two-way communication components. However, while FIG. 1 illustrates an over-ear hearing protection device, it is expressly contemplated that systems and methods herein can be used in in-ear hearing protection devices as well. As shown in FIG. 1, protective headset 100 includes first auditory cup 102A and second auditory cup 102B. Auditory cups 102A and 102B are physically coupled by a stirrup or headband 104. Stirrup or headband 104 may be comprised of any rigid or semi-rigid material, such as plastic, aluminum, steel or any other suitable material. However, it is also expressly contemplated that a headset 100 may not include a stirrup or headband. For example, a behind-the- neck headset 100 may have coupled auditory cups 102A and 102B connected behind a user’s neck, instead of over a user’s head. Additionally, it is expressly contemplated that a helmet version of headset 100 may also be practiced.

[0020] Protective headset 100 may include one or more antennas, such as antenna 107 to receive digital and / or analog signals from devices that are remote from protective headset 100.

[0021] FIG. 1A illustrates cushions 110A and HOB that are attached or otherwise affixed to auditory cups 102A and 102B. Cushions HOA and 110B may abut around the ears of the wearer of headset 100. Cushions 110A and HOB contribute in the capability of auditory cups 102A, 102B to dampen or otherwise reduce ambient sound from an environment outside of auditory cups 102A, 102B. Cushions 110A and 110B may be comprised of any compressible and / or expanding material, such as foam, gel, air, or any other such suitable material. Auditory cups 102A, 102B may be comprised of any rigid or semi-rigid material, such as a plastic, which in some cases, may be a non-conductive, dielectric plastic.

[0022] Auditory cup 102B includes loudspeaker component 112. In some examples, auditory cup 102A may also include a loudspeaker component similar to or the same in structure in functionalityas loudspeaker component 112. Loudspeaker component 112 may emit sound based on an analog or digital signal received or generated by headset 100. Loudspeaker component 112 may include one or more electroacoustic transducers that convert electrical audio signals into sound. Some example loudspeaker components may include a magnet, voice coil, suspension and diaphragm or membrane. Loudspeaker component 112 may be communicatively coupled to the hardware that provides digital and analog two-way communication. As an example, if headset receives a signal representing voice communication, loudspeaker component 112 may emit sound corresponding to the signal.

[0023] Headset 100 also includes a microphone 114. Microphone 114 may be communicatively and / or physically coupled to the hardware that provides digital and analog two-way communication is distributed between first auditory cup 102A and second auditory cup 102B, such as FIG. 1. While microphone 114 is illustrated as extending from a cup 102A, it could also be placed on an exterior of either auditory cup 102A, 102B. Microphone 114 may be any device that translates sound into electrical audio signals. For instance, a person wearing headset 100 may speak, thereby generating sound that is received by microphone 114. Microphone 114 may convert the spoken sounds into electrical audio signals that are received by the hardware that provides digital and analog two-way communication. Electrical audio signals may be transmitted to hardware that provides digital and analog two-way communication via communication link 116.

[0024] Hearing protection device 100 may include, or is communicably coupled to, PTT (Push-to- Talk) 150 functionality.

[0025] FIG. IB illustrates apairofin-earhearing protection devices 160. Similarto hearing protection device 100, in-ear hearing protection includes one or more microphones (not called out in FIG. IB) as well as one or more speakers. Embodiments herein may include in-ear hearing protection devices 160 that provide active hearing protection. As used herein, the term “hearing protection device” may refer to over-ear or in-ear hearing protection interchangeably.

[0026] Often, a user wearing a hearing protection device (e.g. device 100, 160) or another suitable hearing protection device (in-ear, helmet, etc.), has a need to talk to other individuals around them, who are also wearing hearing protection units.

[0027] FIG. 2 illustrates a plurality of workers, each wearing hearing protection devices. Example environment 200 includes a number of workers 210, each wearing hearing protection devices 214. A given worker 210 may need to communicate with one or more of the rest of workers 210, e.g. as indicated by communication lines 220. Each of workers A, B, C and D may have active hearing protection devices 214, requiring communication over a wireless network / radio frequency, etc.

[0028] Communication between workers A-D is generally achieved by devices 214 operating in one of a half-duplex mode or a full-duplex mode. In a “full-duplex” mode, audio is transmitted in bothdirections (e.g. both from C to D and D to C simultaneously) all the time. In a half-duplex mode, audio is only transmitted when a communication feature is actuated - e.g. when a button is press, a switch moved, etc. A half-duplex mode is often used to reduce feedback. Feedback can be caused by a user’s own voice being re -transmitted back by them. If either, or both, of workers C and D are in a noisy area, feedback can be caused by leakage from an echo canceller (exacerbated by ambient noise on either end) making it difficult to hear the speaker. The problem is more significant in a conversation between more than two workers - e.g. a group conversation with A, C and D. However, while a half-duplex mode reduces the amount of ambient noise, it makes the conversation flow less easily - e.g. each user has to actuate a transmitter to speak.

[0029] Full-duplex is desired for ease of conversation. However, in areas of ambient noise for one or more speakers, the speaker’s voice may be difficult to discern. Additionally, based on detected feedback levels another device in a communication system may gate the user’s mic altogether - e.g. based on a user actuating a “push-to-talk” system or by an automatic voice activity detector (VAD). A solution is desired that provides the natural conversation benefits of a full-duplex mode with the noise reduction benefits of a half-duplex mode.

[0030] However, it is desired to have more options for options for dealing with feedback than half or full duplex mode. Systems and methods herein provide tunable mic gain based on measured feedback. Described herein is an example of tunable mic gain that is base on two threshold points. However, it is expressly contemplated that systems and methods may use a greater number of threshold points, look-up tables or other linear / nonlinear equations to adjust gain based on measured feedback.

[0031] Many echo cancellers can calculate a max residual estimate, which is used in systems and methods herein as a way to measure feedback levels. However, it is expressly contemplated that a radio signal could be used directly, by parsing the desired signal from the feedback. Other feedback measuring mechanisms are also envisioned.

[0032] Systems and methods herein provide an adaptive solution by dynamically adjusting a level of gain applied by an amplifier or speaker. In some embodiments, systems and methods herein increase or decrease gain in a linear fashion. In some embodiments, systems and methods herein only apply adaptation to one channel in a multichannel system, e.g. only to a transmitting channel and not the receiving channel.

[0033] FIGS. 3A-3B illustrate examples of adaptive gain reduction in accordance with embodiments herein. FIG. 3 A illustrates one example of how a gain adjustment 340 may be applied at different sound levels 330. For example, up to a first threshold sound value 310, no gain adjustment may be made. Below first threshold 310, ambient noise in the background is quiet enough so as to not significantly interfere with audibility of a speaker. Above a second threshold 320, no additional gainadjustment is made. In some embodiments, above a second threshold the system switches into a halfduplex mode.

[0034] Between thresholds 310 and 320, the gain is adjusted based on the sound level. Illustrated in FIG. 3A is a linear gain adjustment, however it is expressly contemplated that other adjustment algorithms are possible. For example, gain may be adjusted in a stepwise manner as a sound level increases. Additionally, gain may be increased nonlinearly. Additionally, while FIG. 3A illustrates one example rate of adjustment, it is expressly contemplated that this is by example only.

[0035] FIG. 3A illustrates an example where two thresholds 310, 320 are present and the gain increases at a steady rate therebetween. However, it is expressly contemplated that additional thresholds may also be present in other embodiments. For example, a third threshold may be present at a sound level between thresholds 310, 320, and gain may be adjusted at a first rate between threshold 310 and the third threshold, and a second rate between the third threshold and threshold 320. Similarly, systems herein may include more than three thresholds, such as four or five or more than five.

[0036] Using a gain adjustment algorithm like that illustrated in FIG. 3A allows for more nuance than just full or half-duplex mode. It also allows for two-way communication (full-duplex) to be used in more environments, increasing useability for workers.

[0037] FIG. 3B illustrates one example 350 of gain adjustment 380 in a hearing protection device over time 390. The hearing protection device may be a pair of over-ear muffs, in-ear buds, or another suitable hearing protection device. A processing unit of the hearing device - or a controller for the hearing protection device - periodically checks a sound volume and applies a gain adjustment if needed. At time 360, the sound level has changed from an earlier time such that a lower gain can be applied. When a change in gain is needed, systems and methods herein may ramp up or down from a current applied gain to the new applied gain. Ramping up / down may reduce the potential for disrupting an ongoing conversation.

[0038] At time 365, the ramp down is complete. The processing unit checks the sound level, which has not changed since time 360, so no change in applied gain is needed.

[0039] At time 370, a sound level has increased so a new gain adjustment is needed. It is noted that the ramp up rate from 370 to 375 is slower than the ramp down rate from 360 to 365. In some embodiments, changes between gain adjustments occur at a set rate. However, in other embodiments, changes between gain adjustments occur within a set time range. It is expressly contemplated that other constraints on gain adjustments may be possible.

[0040] In some embodiments, a sound level is checked substantially continuously - e.g. multiple times per second. In other embodiments, a sound level is checked periodically - e.g. once every second or less frequently.

[0041] FIGS. 4A-4B illustrate examples of sound processing systems for hearing protection devices. FIG. 4A illustrates an example of a conventional sound processing system 400. Communication is processed on the receiving end (e.g. for the listener). Sound comes in through a radio link 402 where it is initially processed, as indicated by block 404. For example, the radio signal may be decoded and the received signal may undergo equalization. In block 406, a reference input is provided. Reference input 406 is useful for an echo canceller module 412 to adapt. In some embodiments, incoming signal from block 404 is delayed, such that echo canceller 412 has time to adapt. The delay may be imperceptible to a user, on the order of milliseconds, for example. A delay can help to remove feedback from, for example, a speaker signal being picked up by a microphone, causing feedback.

[0042] In block 410, an acoustic coupling is compared to a threshold. Based on the comparison, as illustrated, a microphone may be muted (e.g. entering a half-duplex mode) or may remain in an unmuted state (full-duplex). Echo cancellation is applied by module 412. The sound signal may undergo additional processing 414 before being provided to a radio link 416. For example, in ahearing protection device with active hearing protection, processing in block 414 includes a processor amplifying or suppressing sound at different sound levels. Radio link 416 feeds the processed microphone signal to a radio codec and transmitter. Sound signals processed by system 400 may include sound from communication, ambient environment, device-generated sounds (e.g. voice guidance, alerts, etc.) or any other source.

[0043] FIG. 4B illustrates an example of a sound processing system in accordance with embodiments herein. FIG. 4A illustrates a sound processing system on the receiving-side, e.g. after the sound has been transmitted from a first device, and before the sound is provided to a listener through a speaker.

[0044] In contrast to system 400, in system 450 the communication is processed on the transmitting end (e.g. before speech is transmitted). Adjusting a gain for sound received through the microphone will not affect any other sounds for a listener on the listener’s device. For example, the listener’s device may, therefore, be able to provide unaltered sound signals from their ambient environment to the listener.

[0045] In block 452, a sound signal is received from a microphone. The sound signal is processed by an echo cancellation module 454. The echo cancellation module may operate similarly to that discussed with respect to FIG. 4A, or in another suitable maimer. The echo cancellation module 454 provides a residual echo estimate 456. The residual echo estimate 456 is measurement of the leakage of sound from the reference sound and the input sound, both of which are discussed in FIG. 4A).

[0046] The max residual estimate 460 is compared against a number of thresholds to determine whether a gain adjustment is needed and, if so, which gain adjustment algorithm to use. The max residual estimate 460 is compared against a low threshold 462 and, if the max residual estimate is higher than the low threshold 462, a gain fdter 464 may be applied. If the max residual estimate is lower than the low threshold, the system may apply no gain adjustment. The max residual estimate 460 may also be compared against a high threshold 466 and, based on the result, a gain fdter 468 is applied. If the max residual estimate is higher than the high threshold 466, the system may enter a half-duplex mode. If the max residual estimate is lower than the high threshold 466, a high gain fdter 468 may be applied. Filters 464, 468 are the same, e.g. as illustrated in FIG. 3A.

[0047] Additional processing 470 may be done before an enhanced speech signal 480 is ready for transmission from a speaker’s device to a listener’s device.

[0048] As illustrated in FIG. 4B, the comparisons against thresholds 462, 466 may be done simultaneously. However, it is expressly contemplated that, in some embodiments, the comparisons are done sequentially. This may be advantageous as it may reduce the number of comparisons needed - e.g. if the sound signal is below the low threshold 462, a comparison against high threshold 466 is not needed.

[0049] Additionally, while a comparison against thresholds is illustrated, it is expressly contemplated that the same functionality can be accomplished in other ways. For example, a max residual estimate 456 could be compared to a look-up table, from which a gain adjustment may be determined. Other methods are also contemplated.

[0050] As described herein, while FIG. 4B describes embodiments having two thresholds, it is expressly contemplated that some embodiments utilize more than two thresholds. Each pair of thresholds may define a different gain adjustment algorithm to be applied.

[0051] When a filter - e.g. 464, 468 - needs to be applied, it is expressly contemplated that some embodiments herein adjust a gain gradually instead of applying an abrupt change. For example, a gain may be ramped up or down from a current to a new adjustment level to reduce interruption to the speaker and / or listener. However, it is contemplated that some embodiments have an abrupt change going from a current to a new gain adjustment immediately. Additionally, it is contemplated that some embodiments herein adjust gain by stepping up or stepping down. In embodiments where a gradual change in gain adjustment is employed, the rate of change may be constant or may vary - e.g. the gain adjustment may follow a linear pattern or may follow a nonlinear pattern. The speed of change may also, in some embodiments, be held constant such that the speed of adjustment varies based on a differential between a current applied gain and a new applied gain.

[0052] In embodiments herein, the max residual estimate may be compared against one or more thresholds frequently - e.g. multiple times per second or even more frequently, such as every 100 ms or as often as every 50 ms, or as often as every 30 ms, or as often as every 15 ms, or as often as every 10 ms, or even more frequently. As hearing protection devices are often powered by a battery pack, increasing the frequency has a tradeoff with power conservation. In some embodiments, a frequency may be adjustable to reduce power consumption.

[0053] In some embodiments, the comparison may be done less frequently than echo cancellation. The echo cancellation module may be actuated twice as often as the threshold comparison, for example.

[0054] FIG. 5 illustrates a method of adjusting an applied gain for a hearing protection device in accordance with embodiments herein.

[0055] At block 510, a sound signal is received by a hearing protection device.

[0056] At block 520, an echo cancellation module processes the sound signal in an echo cancellation operation. The echo cancellation operation may include the echo cancellation module receiving a reference sound signal and conducting the echo cancellation operation based on the reference sound signal. The reference sound signal may be provided to the echo cancellation module simultaneously with the sound signal, as illustrated in block 522, in some embodiments. However, in some embodiments, the sound signal is delayed such that the reference signal is received by the echo cancellation module first, as indicated in block 524. The delay may be on the order of milliseconds in some embodiments, such that it is not perceived by a user of a hearing protection device.

[0057] In block 530, a gain adjustment for the sound signal is determined. As described herein, applying a variable gain adjustment to a sound signal allows for more communication options than just full-duplex or half-duplex. Instead, a number of options are available in between half and full-duplex.

[0058] The gain adjustment may be determined by comparing the sound signal, or a representation of the sound signal, to one or more thresholds 532. In some embodiments, a maximum residual echo is received from an echo cancellation module and compared to the one or more thresholds. The sound signal may also be compared directly to a threshold, e.g. in decibels. There may be a low threshold, in some embodiments, that indicates that gain adjustment is necessary. There may be a high threshold, in some embodiments, that indicates that gain adjustment is no longer sufficient, which may cause the device to switch to a half-duplex mode.

[0059] In some embodiments a gain adjustment is made by referencing the sound signal, or a representation of the sound signal, to a look-up table, as illustrated in block 534. Other options for determining a gain adjustment are also contemplated, as indicated in block 536. The gain adjustment could also be applied, for example, using a gain adjustment formula.

[0060] In block 540, the determined adjustment in gain is applied. A gain adjustment may be applied on the transmitting side 542 of a conversation - e.g. on sound generated by a microphone prior to it being transmitted to a second device. A gain adjustment may also be applied on the receiving side 544, e.g. prior to it being broadcast using a speaker.

[0061] As indicated by block 550, method 500 may repeat periodically. For example, the process of receiving a signal, echo cancellation, determining and applying a gain adjustment may repeat every second. Frequently checking and adjusting an applied gain helps to provide a better speech signal in a conversation while also increasing a sound range for a full -duplex mode.

[0062] FIG. 6 illustrates a personal protection device 600. Personal protection device 600 may be a hearing protection device, for example in-ear or over-ear units. However, it is expressly contemplated that systems and methods herein may be useful in any PPE device configured for communication using a microphone 602 and speaker 604.

[0063] Device 600 may include one or more microphones 602 configured to capture ambient sound and / or speech sounds from a user. Device 600 may also include one or more speakers 604. Device 600 may, using a processing unit and memory, conduct one or more operations on a received sound signal prior to broadcasting it through a speaker. For example, device 600 may be an active hearing protection device configured to reduce incoming sounds to a safer level for users.

[0064] A signal receiver 606 receives a sound signal. The sound signal may be received from a microphone 602 of device 600, or may be received from another PPE device 650, for example using a communication component 618. Communication component is configured to operate using any suitable wireless protocol such as, but not limited to, WIFI, Bluetooth®, Zigbee, etc.

[0065] A processing actuator 610 may cause sound processing unit 620 to conduct one or more sound processing operations. While processing unit 620 is illustrated as a single component, it is expressly contemplated that a device may include multiple processors, processing circuitry, cloudbased processing services, or another suitable processing component.

[0066] Sound processing may include using an echo cancellation module 622 to detect and remove an echo in the sound signal. For example, an echo may occur when a sound signal broadcast by the speaker 604 is picked up by a microphone 602 and rebroadcast.

[0067] Sound processing may include adjusting an applied gain to the received signal, using gain adjustment module 624. Applying a gain may include applying a gain adjustment algorithm 634 to the received signal. Generally, communication devices operate in half-duplex or full-duplex mode. For example, when a sound level is loud enough to interfere with a conversation, a device may switch from a full-duplex mode to a half-duplex mode, for example using duplex switch 612 to turn off (or stop transmitting sound from) microphone 604. When in a half-duplex mode, a user of device 600must actuate microphone 602 in order to transmit sound, for example using push-to-talk functionality 614. However, other microphone actuation functionality is also envisioned in some embodiments herein. The gain to be applied may be set by one or more gain adjustment algorithms 634. The gain adjustment algorithm may be selected by the module based on the received signal and / or on a representation of the sound signal.

[0068] In some embodiments, a gain adjustment algorithm 634 is selected based on how an echo residual relates to one or more thresholds. In some embodiments, below a lowest threshold, no gain adjustment is made. Above a highest threshold duplex switch 612 switches from a full-duplex mode to a half-duplex mode. In between the highest and lowest thresholds, one or more gain adjustment algorithm 634 may be used.

[0069] However, it is expressly contemplated that other methods may be used. For example, based on the sound or a sound representation, a look-up table 636 may be used to determine an appropriate gain adjustment.

[0070] For example, the representation of the sound signal may be based on an input power spectral density or an output power spectral density. Or, in some embodiments, the representation of the sound signal is based on an amplitude of the sound signal. For example, the gain adjustment may range between 0% of the amplitude and 100% of the amplitude.

[0071] Additionally, the representation of the sound signal may be based on an input power spectral density or an output power spectral density, in some embodiments. The representation of the sound signal may be based on an amplitude of the sound signal. The representation may also be based on a residual echo estimate.

[0072] Sound processing unit 620 may also have other functionality. For example, device 600 may apply one or more level dependent algorithms 638, using level dependent module 626, to a sound signal. Other sound processing modules may also be used to provide other functionality.

[0073] FIG. 7 is a block diagram of a computing environment that can be used in embodiments shown in previous Figures.

[0074] FIG. 7 is one example of a computing environment in which elements of systems and methods described herein, or parts of them (for example), can be deployed. With reference to FIG. 7, an example system for implementing some embodiments includes a general-purpose computing device in the form of a computer 710. Components of computer 710 may include, but are not limited to, a processing unit 720 (which can comprise a processor), a system memory 730, and a system bus 721 that couples various system components including the system memory to the processing unit 720. The system bus 721 may be any of several types of bus structures including a memory bus or memorycontroller, a peripheral bus, and a local bus using any of a variety of bus architectures. Memory and programs described with respect to systems and methods described herein can be deployed in corresponding portions of FIG. 7.

[0075] Computer 710 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 710 and includes both volatile / nonvolatile media and removable / non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media is different from, and does not include, a modulated data signal or carrier wave. It includes hardware storage media including both volatile / nonvolatile and removable / non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 710. Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.

[0076] The system memory 730 includes computer storage media in the form of volatile and / or nonvolatile memory such as read only memory (ROM) 731 and random-access memory (RAM) 732. A basic input / output system 733 (BIOS) containing the basic routines that help to transfer information between elements within computer 710, such as during start-up, is typically stored in ROM 731. RAM 732 typically contains data and / or program modules that are immediately accessible to and / or presently being operated on by processing unit 720. By way of example, and not limitation, FIG. 7 illustrates operating system 734, application programs 735, other program modules 736, and program data 737.

[0077] The computer 710 may also include other removable / non-removable and volatile / nonvolatile computer storage media. By way of example only, FIG. 7 illustrates a hard disk drive 741 that reads from or writes to non-removable, nonvolatile magnetic media, nonvolatile magnetic disk 752, an optical disk drive 755, and nonvolatile optical disk 756. The hard disk drive 741 is typically connected to the system bus 721 through a non-removable memory interface such as interface 740, and optical disk drive 755 are typically connected to the system bus 721 by a removable memory interface, such as interface 750.

[0078] Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (e.g., ASICs), Application-specific Standard Products (e.g., ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0079] The drives and their associated computer storage media discussed above and illustrated in FIG. 7, provide storage of computer readable instructions, data structures, program modules and other data for the computer 710. In FIG. 7, for example, hard disk drive 741 is illustrated as storing operating system 744, application programs 745, other program modules 746, and program data 747. Note that these components can either be the same as or different from operating system 734, application programs 735, other program modules 736, and program data 737.

[0080] A user may enter commands and information into the computer 710 through input devices such as a keyboard 762, a microphone 763, and a pointing device 761, such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite receiver, scanner, or the like. These and other input devices are often connected to the processing unit 720 through a user input interface 760 that is coupled to the system bus, but may be connected by other interface and bus structures. A visual display 791 or other type of display device is also connected to the system bus 721 via an interface, such as a video interface 790. In addition to the monitor, computers may also include other peripheral output devices such as speakers 797 and printer 796, which may be connected through an output peripheral interface 795.

[0081] The computer 710 is operated in a networked environment using logical connections, such as a Local Area Network (LAN) or Wide Area Network (WAN) to one or more remote computers, such as a remote computer 780.

[0082] When used in a LAN networking environment, the computer 710 is connected to the LAN 771 through a network interface or adapter 770. When used in a WAN networking environment, the computer 710 typically includes a modem 772 or other means for establishing communications over the WAN 773, such as the Internet. In a networked environment, program modules may be stored in a remote memory storage device. FIG. 7 illustrates, for example, that remote application programs 785 can reside on remote computer 780.

[0083] A hearing protection device is presented that includes a microphone, a speaker, and processing circuitry and memory configured to, when actuated: receive a sound signal, analyze the sound signal, based on the analysis, apply a gain adjustment to the sound signal, and communicate theadjusted sound signal. The hearing protection device is configured to operate in a full-duplex mode and in a half-duplex mode.

[0084] The device may be implemented such that analyzing the sound signal includes the processing circuitry being configured to: generate a representation of the sound signal and compare the representation of the sound signal to a first threshold and a second threshold. The second threshold is higher than the first threshold. If the representation of the sound signal is between the first and second threshold, the device is configured to apply the gain adjustment.

[0085] The device may be implemented such that, if the representation of the sound signal is above the second threshold, causing the hearing protection device to enter the half-duplex mode.

[0086] The device may be implemented such that the processing circuitry repeats the comparison and adjustment operations periodically.

[0087] The device may be implemented such that the representation of the sound signal is based on an input power spectral density or an output power spectral density.

[0088] The device may be implemented such that the representation of the sound signal is based on an amplitude of the sound signal.

[0089] The device may be implemented such that the representation is based on a residual echo estimate.

[0090] The device may be implemented such that the processing circuitry applies a gain adjustment based on a gain adjustment algorithm.

[0091] The device may further include an echo cancellation module configured to apply an echo cancellation algorithm to the sound signal.

[0092] The device may be implemented such that the applied gain adjustment is based on a residual echo estimate from the echo cancellation module.

[0093] The device may be implemented such that, if the residual echo estimate is below a high threshold and above a low threshold, the applied gain is based on a gain adjustment algorithm.

[0094] The device may be implemented such that, if the residual echo estimate is above the high threshold, the applied gain is 0 and the hearing protection device enters the half-duplex mode.

[0095] The device may be implemented such that, if the residual echo estimate is below the low threshold, the applied gain is zero.

[0096] The device may be implemented such that the processing circuitry generates, compares and applies more frequently than once per second.

[0097] The device may be implemented such that a first gain adjustment is made at a first time, a second gain adjustment is made at a second time, and the first and second adjustments are different.

[0098] The device may be implemented such that applying the gain adjustment includes changes a current gain to a new gain over a time period.

[0099] The device may be implemented such that applying the gain adjustment includes changing a current gain to a new gain instantly.

[0100] The device may be implemented such that the sound signal is received from the microphone, and the adjusted sound signal is communicated to a second device using a communication component.

[0101] The device may be implemented such that the sound signal is received from a second device using the communication component and the gain adjustment is applied before the adjusted sound signal is provided to the speaker.

[0102] A method for adapting a microphone gain is presented that includes receiving a sound signal from a sound source, determining a gain adjustment for application to the sound signal. Determining includes retrieving a gain adjustment based on a representation of the sound signal. The method also includes generating an adjusted sound signal by applying the determined gain adjustment to the sound signal, and communicating the adjusted sound signal to a speaker.

[0103] The method may be implemented such that the sound source includes a microphone.

[0104] The method may further include applying an echo cancellation algorithm to the sound signal;

[0105] generating a representation of the sound signal. The representation includes a residual echo estimate. The gain adjustment is determined using the residual echo estimate.

[0106] The method may be implemented such that determining the gain adjustment includes comparing the residual echo estimate to a threshold and, based on the comparison, retrieving the gain adjustment.

[0107] The method may be implemented such that the threshold is a first threshold, and further including a second threshold higher than the first threshold. Determining includes: detecting that the residual echo estimate is between the first and second threshold. Retrieving the gain adjustment includes retrieving a gain adjustment algorithm.

[0108] The method may be implemented such that applying the gain adjustment includes changing an applied gain from a current gain to a new gain.

[0109] The method may be implemented such that changing includes directly adjusting from the current to the new gain.

[0110] The method may be implemented such that changing includes gradually adjusting from the current to the new gain.

[0111] The method may be implemented such that the microphone and the speaker are part of the same device.

[0112] The method may be implemented such that the microphone is part of a first device and the speaker is part of a second device.

[0113] The method may be implemented such that the sound source includes a second device.

[0114] A personal protection device is presented that includes a microphone configured to capture a sound signal, an echo cancellation module configured to apply an echo cancellation algorithm to the sound signal to generate a second sound signal, and generate a residual echo estimate, a gain adjustment module configured to apply a gain adjustment algorithm to the second sound signal to generate a third sound signal, and a communication component configured to transmit the third sound signal to a second device.

[0115] The device may be implemented such that the echo cancellation module applies the echo cancellation algorithm periodically, and the gain adjustment module applies the gain adjustment algorithm periodically.

[0116] The device may be implemented such that the echo cancellation module operates more frequently than the gain adjustment module.

[0117] The device may be implemented such that the gain adjustment module applies the gain adjustment more frequently than once per second.

[0118] The device may be implemented such that the gain adjustment module applies the gain adjustment more frequently than ten times per second.

[0119] The device may be implemented such that the gain adjustment algorithm: makes no adjustment if the residual echo estimate is below a low threshold, switches the device into a halfduplex mode if the residual echo estimate is above a high threshold, and generates a new gain to apply to the second signal, if the residual echo estimate is between the low threshold and the high threshold.

[0120] The device may be implemented such that the new gain has a linear relationship to the residual echo estimate.

[0121] The device may be implemented such that the new gain has a non-linear relationship to the residual echo estimate.

[0122] The device may be implemented such that the gain adjustment module switches a current gain to the new gain.

[0123] The device may be implemented such that the gain adjustment module changes the current gain to the new gain gradually.

[0124] A sound processing component for a communications system is presented that includes a microphone configured to capture a sound signal, an echo cancellation module configured to apply anecho cancellation filter to the sound signal, generating a filtered sound signal and a residual echo estimate, and a gain adjustment module configured to, based on the residual echo estimate, generate and apply a gain algorithm to the filtered sound signal, generating an enhanced sound signal. If the residual echo estimate is above zero and below a low threshold, the gain algorithm applies no change. If the residual echo estimate is above a high threshold, the gain algorithm switches the communications system into a half-duplex mode. If the residual echo estimate is above the low threshold and below the high threshold, the gain algorithm adjusts the gain applied to the filtered sound from a current gain to a new gain. The component also includes a signal transmitter configured to transmit the enhanced sound signal.

[0125] The component may be implemented such that the component is part of a hearing protection device, and the signal transmitter transmits the enhanced sound signal to a second device.

[0126] The component may be implemented such that the signal transmitter transmits using a wireless protocol.

[0127] The component may be implemented such that the echo cancellation module is configured to receive a reference sound signal before receiving the sound signal.

[0128] The component may be implemented such that the gain is adjusted from the current gain to the new gain gradually.

[0129] The component may be implemented such that the gain adjustment module is configured to generate and apply the gain algorithm periodically.

[0130] The component may be implemented such that the gain adjustment module is configured to generate and apply the gain algorithm more frequently than once per second.

[0131] The component may be implemented such that the gain adjustment module is configured to generate and apply the gain algorithm more frequently than ten times per second.

[0132] The component may be implemented such that the echo cancellation module is configured to operate more frequently than the gain adjustment module.

[0133] The component may be implemented such that the gain algorithm includes a linear relationship between the residual echo estimate and the new gain.

[0134] The component may be implemented such that the gain algorithm includes a nonlinear relationship between the residual echo estimate and the new gain.EXAMPLESEXAMPLE 1

[0135] An esp32-wroom-32 microcontroller was programmed with the parameters listed in Table 1. The parameters were selected based on the hardware used in this Example . These parameterscan be tuned for different hardware platforms. In Table 1, MAXS refers to the Maximum Signal (e.g.MAX 16 refers to the Maximum Signal possible for a signed 16 bit representation).Table 1:

[0136] The attack ducking to low threshold gain happens immediately if residual signal is above low threshold. If the signal goes back to below the low threshold, then the release is done only after FRAMES DUCKGAIN LOW. However, if a signal moves from low threshold to high threshold, then the attack ducking to high is applied immediately, without waiting for the 100 frames to pass. If the signal goes back to below high / low threshold, then the release is done only after the frames are applied.

[0137] To calculate the ramp angle, the attack and release are subtracted and added respectively to the gain, a little each frame until the target gain is reached, resulting in a gain change per time interval.

[0138] FIG. 8 illustrates an example of how a gain adjustment algorithm programmed with the specifications in Table 1 might be applied.EXAMPLE 2

[0139] A gain adjustment algorithm was simulated on a PC environment with the parameters listed in Table 2. The parameters were selected based on the hardware used in this Example. These parameters can be tuned for different hardware platforms. A trace diagram illustrating the percent of max overtime for both the residual echo and the microphone gain is illustrated in FIG. 9.

[0140] The downward slope of the post-processing gain was determined by the “Duck Attack.”The gain was held constant at the value “Duck Gain Low” for “Frames Applied.” The upward slope of the post-processing gain is determined by the value “Duck Release.” The gain is held constant at the value “Duck Gain High” for “Frames Applied.”TABLE 2

Claims

WHAT IS CLAIMED IS1. A hearing protection device comprising : a microphone; a speaker; processing circuitry and memory configured to, when actuated: receive a sound signal; analyze the sound signal; based on the analysis, apply a gain adjustment to the sound signal; and communicate the adjusted sound signal; and wherein the hearing protection device is configured to operate in a full-duplex mode and in a half-duplex mode.

2. The device of claim 1, wherein analyzing the sound signal comprises the processing circuitry being configured to: generate a representation of the sound signal; and compare the representation of the sound signal to a first threshold and a second threshold, wherein the second threshold is higher than the first threshold; and wherein, if the representation of the sound signal is between the first and second threshold, apply the gain adjustment.

3. The device of claim 2 wherein, if the representation of the sound signal is above the second threshold, causing the hearing protection device to enter the half-duplex mode.

4. The device of claim 2, wherein the processing circuitry repeats the comparison and adjustment operations periodically.

5. The device of claim 2, wherein the representation of the sound signal is based on an input power spectral density or an output power spectral density.

6. The device of claim 2, wherein the representation of the sound signal is based on an amplitude of the sound signal.

7. The device of claim 2, wherein the representation is based on a residual echo estimate.

8. The device of any of claims 1-7, and further comprising an echo cancellation module configured to apply an echo cancellation algorithm to the sound signal.

9. The device of claim 8, wherein the applied gain adjustment is based on a residual echo estimate from the echo cancellation module.

10. The device of claim 9, wherein, if the residual echo estimate is below a high threshold and above a low threshold, the applied gain is based on a gain adjustment algorithm.

11. The device of claim 10, wherein, if the residual echo estimate is above the high threshold, the applied gain is 0 and the hearing protection device enters the half-duplex mode, and wherein, if the residual echo estimate is below the low threshold, the applied gain is zero.

12. The device of claim 9, wherein the processing circuitry generates, compares and applies more frequently than once per second.

13. The device of any of claims 1-12, wherein the sound signal is received from the microphone, and wherein the adjusted sound signal is communicated to a second device using a communication component.

14. The device of any of claims 1-13, wherein the sound signal is received from a second device using the communication component and wherein the gain adjustment is applied before the adjusted sound signal is provided to the speaker.

15. A method for adapting a microphone gain, the method comprising: receiving a sound signal from a sound source; determining a gain adjustment for application to the sound signal, wherein determining comprises retrieving a gain adjustment based on a representation of the sound signal; generating an adjusted sound signal by applying the determined gain adjustment to the sound signal; and communicating the adjusted sound signal to a speaker.

16. The method of claim 15, wherein the sound source comprises a microphone.

17. The method of claim 15 or 16, and further comprising: applying an echo cancellation algorithm to the sound signal; generating a representation of the sound signal, wherein the representation comprises a residual echo estimate; and wherein the gain adjustment is determined using the residual echo estimate.

18. The method of claim 17, wherein determining the gain adjustment comprises comparing the residual echo estimate to a threshold and, based on the comparison, retrieving the gain adjustment.

19. The method of claim 18, wherein the threshold is a first threshold, and further comprising a second threshold higher than the first threshold and wherein determining comprises: detecting that the residual echo estimate is between the first and second threshold; and wherein retrieving the gain adjustment comprises retrieving a gain adjustment algorithm.

20. The method of any of claims 15-19, wherein applying the gain adjustment comprises changing an applied gain from a current gain to a new gain.

21. The method of any of claims 15-20, wherein the microphone and the speaker are part of the same device.

22. The method of any of claims 15-21, wherein the microphone is part of a first device and the speaker is part of a second device.

23. A personal protection device comprising: a microphone configured to capture a sound signal; an echo cancellation module configured to apply an echo cancellation algorithm to the sound signal to generate a second sound signal, and generate a residual echo estimate; a gain adjustment module configured to apply a gain adjustment algorithm to the second sound signal to generate a third sound signal; and a communication component configured to transmit the third sound signal to a second device.

24. The device of claim 23, wherein the echo cancellation module applies the echo cancellation algorithm periodically, and wherein the gain adjustment module applies the gain adjustment algorithm periodically.

25. The device of claim 24, wherein the echo cancellation module operates more frequently than the gain adjustment module.

26. The device of claim 24, wherein the gain adjustment module applies the gain adjustment more frequently than once per second.

27. The device of claim 26, wherein the gain adjustment module applies the gain adjustment more frequently than ten times per second.

28. The device of any of claims 23-27, wherein the gain adjustment algorithm: makes no adjustment if the residual echo estimate is below a low threshold; switches the device into a half-duplex mode if the residual echo estimate is above a high threshold; and generates a new gain to apply to the second signal, if the residual echo estimate is between the low threshold and the high threshold.

29. The device of claim 28, wherein the new gain has a linear relationship to the residual echo estimate.

30. The device of claim 28, wherein the new gain has a non-linear relationship to the residual echo estimate.

31. The device of claim 28, wherein the gain adjustment module switches a current gain to the new gain.

32. A sound processing component for a communications system, the component comprising: a microphone configured to capture a sound signal; an echo cancellation module configured to apply an echo cancellation filter to the sound signal, generating a filtered sound signal and a residual echo estimate; a gain adjustment module configured to, based on the residual echo estimate, generate and apply a gain algorithm to the filtered sound signal, generating an enhanced sound signal; wherein:if the residual echo estimate is above zero and below a low threshold, the gain algorithm applies no change; if the residual echo estimate is above a high threshold, the gain algorithm switches the communications system into a half-duplex mode; and if the residual echo estimate is above the low threshold and below the high threshold, the gain algorithm adjusts the gain applied to the filtered sound from a current gain to a new gain; and a signal transmitter configured to transmit the enhanced sound signal.

33. The component of claim 32, wherein the component is part of a hearing protection device, and wherein the signal transmitter transmits the enhanced sound signal to a second device.

34. The component of claim 33, wherein the signal transmitter transmits using a wireless protocol.

35. The component of any of claims 32-34, wherein the echo cancellation module is configured to receive a reference sound signal before receiving the sound signal.

36. The component of any of claims 32-35, wherein the gain adjustment module is configured to generate and apply the gain algorithm periodically.

37. The component of claim 36, wherein the gain adjustment module is configured to generate and apply the gain algorithm more frequently than once per second.

38. The component of claim 36, wherein the gain adjustment module is configured to generate and apply the gain algorithm more frequently than ten times per second.

39. The component of claim 36, wherein the echo cancellation module is configured to operate more frequently than the gain adjustment module.

40. The component of any of claims 32-39, wherein the gain algorithm comprises a linear relationship between the residual echo estimate and the new gain.

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