An apparatus and method for real-time audio processing employs a gaze detection sensor to detect a direction of a user's gaze and output a gaze signal corresponding to the detected direction of the user's gaze. A digital signal processing unit responds to a plurality of signals corresponding to a plurality of sounds received at the apparatus, and the determined direction of gaze to identify a signal of interest from the plurality of signals using the gaze signal. The signal of interest is processed for output to the user. In embodiments, a microphone array provides the plurality of signals. An imaging sensor may work with either the microphone array or the gaze detection sensor to identify the signal of interest.

TECHNICAL FIELD

This application relates generally to the field of audio processing and in particular, sound detection and enhancement.

BACKGROUND

There are many environments where the ability to hear and distinguish a certain noise or sounds from others in the environment is important. For example, in a crowded lecture theater, an audience member listening to a speaker/lecturer may encounter noise from a variety of sources. These could include noise sources inside the theater, such as air conditioning or other ventilation, cellphones of other audience members, people talking or shuffling papers during the speaker/lecturer's presentation, and the like. Noise also could come from outside the lecture theater (e.g. traffic, hallway voices, custodians operating cleaning equipment, and the like). In such environments, a listener's ability to discern or hear desired sounds from others can be diminished. In addition, as a speaker or listener moves about the lecture theater, the sound conditions may change. For example, if the listener is sitting too close to the speaker, or a set of audio speakers, the sound level may be too high. Alternatively, if the listener is too far away from the sound sources, the sound level may be too low. Other noisy environments, such as parties, busy public streets, and stadiums also present hearing challenges.

Noise cancellation systems process noise based on existing pre-determined criteria. For example, some systems, such as those utilizing automatic gain control, utilize a reference level and determine whether a noise signal is above that level. If the noise signal is not above the reference level, then it is considered unwanted noise and is removed. Such systems do not take into account factors which may, for example, make an otherwise low-level signal a desired signal.

DETAILED DESCRIPTION

Referring toFIG. 1, according to an embodiment, a real-time audio processing device200may be located in a lecture hall or theater101, where a listener may wish to focus on sound coming from a speaker/lecturer or other sound source102. The device200may be closer to the source102than to other sound/noise sources106, may receive a plurality of sounds103, some of which may be desired, and some of which may be noise. The plurality of sounds may include a desired sound104, noise105from noise sources106within a certain vicinity101of the speaker, and/or any other type of noise.

Relative positioning and sound levels in other environments can represent similar issues to those encountered in a lecture hall or theater. Any kind of crowded room, as for example at a party or reception in which two people might wish to converse in a room full of other conversations and unrelated noise; a busy public street or crowded public transportation vehicle; or even an office with cubicles can present listening challenges. In any of the environments listed here, the actual sound source on which the listener wishes to focus may not be the loudest sound source in the vicinity.

Referring now toFIG. 2, the real-time audio processing device200may include a microphone array201, having one or more microphones202. In an embodiment, the microphone array201as well as the real-time audio processing device200may be integrated into a user's headphones. Microphone array201detects the plurality of sounds and converts the sounds into a plurality of signals. The position of each microphone202within the array201, together with the magnitude of signals coming from each microphone, can provide information about directionality and sound level. Microphone array201then outputs the plurality of signals to a signal processing unit203of the real-time audio processing device200.

In the following discussion, signal processing unit203will be referred to as a digital signal processing unit, or DSP unit. DSP chips are known to be designed, configured, and/or otherwise implemented in a way that makes sound processing efficient. However, the techniques and concepts described herein also may be implemented in a wide range of suitably programmed (micro)processors, (micro)controllers, or other computing or processing devices.

In an embodiment, DSP unit203may use information about which signal comes from which microphone202in array201to determine sound directionality and relative level. Using this information, together with the signals, the DSP unit203may determine a magnitude, frequency and direction of arrival component for each signal within the plurality of signals. DSP unit203may implement one or more direction finding algorithms to determine the direction of arrival component of each signal. Such algorithms may include, by way of non-limiting example, Time Difference of Arrival, Triangulation, and Particle Velocity Measurement. Other algorithms will be known to ordinarily skilled artisans. In an embodiment, DSP unit203also determines a level of persistence for each signal in the plurality of signals. In an embodiment, the DSP unit203may determine persistence in either a signal's amplitude, or frequency, or duration, or all three. In this manner, real-time audio processing device200may distinguish between transient, sudden, and/or random sounds, on the one hand, and, for example, speech (which tends to have a certain degree of persistence in terms of level and/or duration).

Referring again toFIG. 2, real-time audio processing device200may include a gaze detection sensor204to determine a direction of the user's gaze during operation of the real-time audio processing device. The gaze detection sensor204may be a gyroscope sensor, accelerometer or any sensor device capable of sensing rotational motion or changes in angular velocity. In this kind of implementation, based on a position of the sensor204relative to the user's line of sight, movement and/or position of a user's head may be a surrogate for the user's actual gaze.

In an embodiment, the gaze detection sensor204may use technology similar to that in Google Glass™, for example, to detect the actual position of the user's eyes. Technology starting to appear in helmets or goggles that pilots wear, enabling them to move their eyes to control aspects of aircraft operation instead of having to move their hands from the controls, also could be used. In another embodiment, the gaze detection sensor204may use the relative position of the microphones in the microphone array201as placed on the user's head or body, and movement of the array, to derive information about the direction of the user's gaze. However, this approach likely would be less reliable because the desired sound source on which the listener may be focusing may not be the loudest source.

In an embodiment, DSP unit203may use the user's gaze to determine which sound(s) to emphasize or de-emphasize. Where there are multiple sound sources, as for example when talking to someone at a loud party where music is playing or other conversations are going on nearby, it may be that the desired sound (e.g. the speaker with whom the user is conversing) may not be the loudest sound source where the listener is positioned. Therefore, it may be desirable to be able to emphasize sound coming from the direction of the speaker, and de-emphasize sound coming from other directions. Aspects of embodiments of this approach now will be discussed.

As the user's gaze (or head or body position) tracks the direction of the speaker, the gaze detection sensor204may generate a signal corresponding to the direction of the user's gaze. DSP unit203may confirm that the direction of the user's gaze corresponds to the direction of the speaker's location by comparing movement of the array201or gaze detection sensor204relative to sound coming from the direction of the speaker.

According to an embodiment, the DSP unit203may implement any of a number of algorithms, known to ordinarily skilled artisans, for detecting and differentiating unwanted noise to supplement the real-time audio processing device's sound processing capabilities. By way of example only, the real-time audio processing device200may utilize acoustical beam-forming techniques, either as a separate module or algorithm, or, as depicted inFIG. 2, as module205within DSP unit203. Using acoustical beam-forming is another way to emphasize sound coming from one direction, while de-emphasizing sound coming from other directions.

In an embodiment, when DSP unit203has confirmed that the user's gaze is tracking the speaker or other desired sound source, DSP unit203may determine whether the user's gaze is continuing to track. For example, using an accelerometer or other motion sensor, DSP unit203may determine the change in head movement, and/or change in speed of head movement over the same or different given time interval(s). More than a certain (threshold) amount of movement may indicate a change in focus from the speaker to another source. More than a certain (threshold) amount of speed of movement may indicate a head jerk, and not a change in focus. Depending on desired effect, the DSP unit203may be instructed either to heed or to ignore gaze direction shifts that gaze detection sensor204registers. Thus, for example, if a user turns, quickly or slowly, to hear another speaker (e.g. someone sitting next to the user at a lecture), and the user's gaze remains in that other speaker's direction for long enough, the DSP unit203may determine that the user has changed his/her gaze, and can focus on the nearby speaker.

DSP unit203can compare the direction of the user's gaze with the direction of sound arrival as represented by respective signals within the plurality of received signals. DSP unit203also can compare the magnitude of each signal within the plurality of received signals with each other to a preset magnitude reference threshold. DSP unit203then can determine which signals from the plurality of received signals have a direction of arrival component that matches the direction of the user's gaze and which signals have a magnitude that meets or exceeds the preset magnitude threshold. Signals having a direction of arrival component that matches the direction of the user's gaze and a magnitude that meets or exceeds the magnitude threshold may be considered as representing the desired sound, while signals that do not have a matching direction of arrival component or that are not sufficiently persistent may be considered as representing unwanted noise. If no signals having a direction of arrival component that corresponds to the detected direction of the user's gaze, and a magnitude that meets or exceeds the magnitude consistency threshold are detected, then the real-time audio processing device will restart and attempt to ascertain the desired sound again. In such an embodiment, sound magnitude may be given more significance than in other embodiments, in which the user's gaze is given the most emphasis.

In an embodiment, DSP unit203may compare a persistence of each signal within the plurality of signals to a persistence threshold. Persistence may be a function of both amplitude (magnitude) and duration. Signals that do not meet the persistence threshold may be considered to be unwanted noise. The factors discussed above, including direction of arrival, magnitude, and persistence value are exemplary only, and should not be construed as limiting the number of factors the DSP unit203can take into account in determining the desired sound.

In an embodiment, DSP unit203may assign weights to the direction of arrival, magnitude and persistence factors. DSP unit203may then take the weighted sum of all factors for each signal within the plurality of signals and compare the sum to a weighted reference factor. If the weighted sum of all factors for any signal within the plurality of signals meets or exceeds the weighted reference factor, then DSP unit203may determine that signal to be the desired sound signal. Signals not having a weighted sum that meets or exceeds the respective weighted reference factor may be considered as unwanted noise.

After determining which signal among the plurality of received signals represents the desired sound, DSP unit203may remove (cancel) or deemphasize (diminish) any signals representing unwanted noise. By way of example only, DSP unit203may remove signals representing unwanted noise by capturing a frequency profile of the unwanted noise, inverting the frequency profile and offsetting it, which provides the opposite of the unwanted noise signal. The opposite noise signal is then output to effectively cancel the unwanted noise. In an embodiment, DSP unit203could provide additional amplification to the desired sound, and correspondingly less amplification to the unwanted noise, thus emphasizing the desired sound as compared to the unwanted noise.

In an embodiment, as depicted inFIG. 2, the real-time audio processing device may include an imaging sensor207to look for the face of a speaker. The gaze detection sensor204uses the direction of the user's gaze to determine whether the user is looking at a desired sound source which may not be the loudest of the sources, but still is desired. The imaging sensor207uses the direction of the speaker's gaze, and may work with microphones202in microphone array201to determine that a loudest, desired sound source is coming from a speaker to whom the user wishes to listen. Such an embodiment may be useful where a listener turns his/her head briefly, for example, to make notes of a lecturer's remarks. In an embodiment, imaging sensor207could work with gaze detection sensor204to confirm a sound source direction, as for example when the user and the speaker are looking at each other.

There may be times when it is desirable to override the gaze detection sensor204. For example, in a noisy environment, such as a crowded lecture hall or a moving subway car, it may be useful to lock on to the speaker as the desired source of sound, even though there will be times when the user will want to look away. In a lecture hall, for example, as noted earlier, the listener may want to look at his/her notebook, computer, or tablet, or consult some textual source while the lecturer is speaking. In a moving subway car, for example, the user may want to look at a map posted in the car. Looking away in such circumstances may change the sound source. But if the user can override the gaze detection sensor, the sound source can remain as is. The override may be temporary (e.g. changing after a short period of time, such as 5-10 seconds), or it may be permanent until the user turns the override off. Such an override may be accomplished, for example, via an override switch208which, while shown within DSP unit203, may be onboard microphone array201, or associated with gaze detection sensor204, for the user's convenience.

The imaging sensor207may be a video sensor or infra-red sensor or any sensor device with similar functionality. In an embodiment, facial recognition technology, as used in digital cameras and other applications, may be used, to the extent that, for example, such technology facilitates viewing of a speaker's eyes. The imaging sensor207may output signals corresponding to received images to DSP unit203. DSP unit203may monitor the received signals of the imaging sensor207and may utilize an algorithm, including facial recognition or thermal recognition or the like, to determine whether a signal or signals received from imaging sensor207correspond to an image of a person speaking in the user's direction. Upon detecting that a person is speaking in the direction of the user, DSP unit203may emphasize signals coming from that direction, and deemphasize or cancel signals coming from a different direction (e.g. more than a certain number of degrees from a determined virtual centerline running between the speaker and the listener). The real-time audio processing device then may further process the signals coming from the speaker's direction to be at an optimal level by modifying the volume and frequency parameters of the signals to appropriate volume and frequency parameters as discussed previously.

There may be situations, for example, in a noisy room, in which two people who want to converse are across the room from each other, with several conversations going on in the area between them. If the people catch each other's eye, then imaging sensor207and/or gaze detection204may lock DSP unit203in to the speech of the person across the room, emphasizing that sound to the exclusion of other sound, so that the two people can converse, even when they are not next to each other. In this scenario, one person may wish to catch the eye of the person across the room. To facilitate that being done, the person seeking the attention may ping the person across the room to alert him/her that attention and/or conversation is desired. The person across the room, upon receiving the ping, may find the person seeking the attention and engage in eye contact. In that event, the real-time audio processing device200may function as described above. If the person across the room wishes to ignore the request, s/he may do so, of course.

Pinging may be done in any number of ways, from a signal broadcast between devices200that each person is wearing/using, to sending a signal using an app on a smartphone or other handheld device, or the like.

In an embodiment, a user may wish to communicate to a number of people in a room, a hall, an auditorium, or the like that s/he wants to have a conversation about something. To achieve that communication, the user may be able to broadcast a signal, unique to the user or to the user's source of sound, to the people in the area. In an embodiment, other users' devices200may receive the signal, and can respond by locking into that signal and hence to the initiator's sound/voice. Also in an embodiment, users may be able to access a list of various potential immediately local speakers via a smartphone or tablet app, and may select one of those speakers. In that event, the app could communicate the information to its respective device200and thus lock into that signal.

According to an embodiment, imaging sensor207may function as gaze detection sensor204. In another embodiment, particularly in a lecture hall or the like, imaging sensor207may supplement gaze detection sensor by assisting the DSP unit203to process signals from a speaker, even in a situation in which the user is not looking in the direction of the speaker. DSP unit may give gaze detection sensor204priority over imaging sensor207. In this way, when a user is looking at a lecturer, for example, gaze detection sensor204can work primarily with DSP unit203to ensure that the lecturer's speech is processed appropriately. When the user's gaze points downward to take notes, for example, imaging sensor207may be given priority. Alternatively, it may be recognized that when a user is looking down to take notes, gaze detection sensor204will show that the user is not looking in a direction from which sound is coming. In that circumstance, DSP unit203may ignore output from gaze detection sensor204. This would be one way of implementing the functionality discussed above.

According to an embodiment, DSP unit203may be connected to a music or video player. Upon determining that there is someone speaking in the direction of the user, DSP unit203may be configured to automatically pause playback from the music or video player. In this fashion, a user/listener may opt to listen to someone who is speaking to him/her without having to fumble for playback controls.

According to an embodiment, if the user/listener is looking at a speaker while using the music or video player, it may be possible to have the real-time audio processing device determine that the user/listener wants to hear the speaker rather than playback from the music or video player. The device could respond to an audio command, or could use the gaze detection sensor204in the DSP unit203to instruct the device to suspend or pause playback so that the user/listener can hear the speaker.

In an embodiment, it may be desirable to be able to identify a sound source without the user looking directly at it. For example, in a symphony orchestra, often there are a plurality of different string instruments (e.g. violins, violas, cellos, basses), and/or a plurality of woodwinds (e.g. oboes, bassoons), and/or a plurality of brass instruments (e.g. trumpet, trombone, saxophone, French horn, tuba), and/or a plurality of percussion instruments (e.g. triangle, bass drum, tympani, snare drum), and/or keyboard instruments (e.g. piano, organ, harpsichord, electronic keyboard, clavier). The listings within these categories is not intended to be extensive, but merely to give an idea of the range of different instruments. Marching bands may have similar ranges of instruments.

In one of the just-described scenarios, a listener may want to focus on the first violinist, or on the second viola (e.g. in the case of a friend or relative playing in the orchestra who is not the concertmaster or the first violinist, who would be more readily identifiable by gaze). Or, there may be a soloist who is none of these things. In such scenarios, each performer may have metadata associated with him/her, which then would be identifiable with the musical instrument the performer is playing. If the DSP unit has, for example, a table with that metadata in it—something that could be downloaded prior to the performance, either at the concert or beforehand via an app), then during the concert, the user could input instruction to focus on the instrument(s) associated with particular metadata for one or more instruments, so that the sound from those instrument(s) would be highlighted.

Referring now toFIG. 3, a method for real-time audio detection and processing begins at301, when the real-time audio processing device receives a plurality of sounds and processes them into a plurality of signals. At302, a direction of a user's gaze is determined. At303, the DSP unit203uses the detected gaze to identify which signal(s) within the received plurality of signals correspond to desired sound and which signal(s) within the plurality of signals correspond to unwanted noise. The process may cycle through as shown at304inFIG. 3until desired sound is identified successfully. At305, the unwanted noise signals are removed or deemphasized using one or more of the algorithms discussed above. At306, the desired sounds are processed to bring them into conformity with preset volume and frequency parameters. Finally, at307, in an embodiment in which the user is wearing a audio playback device in which the real-time audio processing device is incorporated, playback may be paused to facilitate the user's hearing the speaker. Each of301-307may be implemented in accordance with any of the embodiments and techniques described above with respect toFIG. 2.

FIG. 4represents a variant of the flow and accompanying description forFIG. 3, taking into account the use of imaging sensor207in conjunction with gaze detection sensor204according to an embodiment. At401, the real-time audio processing device receives a plurality of sounds and processes them into a plurality of signals. At402, a direction of a speaker's gaze is determined. At403, the DSP unit203uses the detected speaker's gaze to identify which signal(s) within the received plurality of signals correspond to desired sound and which signal(s) within the plurality of signals correspond to unwanted noise. At404, if there is not a match, a further action may be taken to determine whether imaging sensor207should be given priority over gaze detection sensor204. As discussed previously, one such situation may occur when a listener/user is looking down, for example, to take notes. If the user is not looking down, the process may cycle through as shown inFIG. 4until desired sound is identified successfully. If the user is looking down, then priority may be given to the imaging sensor207, or to microphone array202, along the lines discussed earlier.

In an embodiment, at405, there may be processing to determine whether the noise cancelling algorithm being implemented is working successfully, e.g. to see whether sound that is not coming from the speaker or the desired sound source is being identified successfully. If not, then at406the process may be returned to the beginning, as shown inFIG. 4, or to another place in the flow chart, e.g.402or403. If there is sufficient correlation, i.e. if the unwanted sound is identified correctly, then at407, the unwanted noise signals are removed or deemphasized using one or more of the algorithms discussed above. At408, the desired sounds are processed to bring them into conformity with preset volume and frequency parameters. Each of401-408may be implemented in accordance with any of the embodiments and techniques described above with respect toFIG. 2.

The elements discussed above with respect toFIGS. 3 and 4might be initiated automatically, upon powering up of the real-time audio processing device. Alternatively, the device might respond to a suitable user verbal command. Techniques for responding to user verbal commands will be known to ordinarily skilled artisans.

The disclosed embodiments are not limited in their applicability to music halls, lecture halls, or theaters, or to lecturers or speakers. At a party or in a crowded room, where multiple speakers may be present in proximity to a listener, some of those speakers being even louder than the one to whom a user may wish to listen, the ability to look at a particular speaker could be helpful in emphasizing that speaker's voice and cancelling out or de-emphasizing the voices of others, or sounds coming from different directions. Embodiments could be used at sporting events, subways, public streets, restaurants, or in any environment in which directional reception of sound would be helpful.

To the extent that method or apparatus embodiments herein are described as having certain numbers of elements, it should be understood that fewer than all of the elements may be necessary to define a complete claim. In addition, sequences of operations or functions described in various embodiments do not require or imply a requirement for such sequences in practicing any of the appended claims. Operations or functions may be performed in any sequence to effectuate the goals of the disclosed embodiments. This is the case, for example, with respect to the operations inFIG. 3, in which, for example, a user's gaze direction might be processed first, rather than processing sounds as shown, as it might be preferable to determine first whether the user's gaze has focused, and then proceed to process received sound.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.