US20210082435A1 - Multi-mode guard for voice commands - Google Patents

Abstract

Embodiments may be implemented by a computing device, such as a head-mountable display, in order to use a single guard phrase to enable different voice commands in different interface modes. An example device includes an audio sensor and a computing system configured to analyze audio data captured by the audio sensor to detect speech that includes a predefined guard phrase, and to operate in a plurality of different interface modes comprising at least a first and a second interface mode. During operation in the first interface mode, the computing system may initially disable one or more first-mode speech commands, and respond to detection of the guard phrase by enabling the one or more first-mode speech commands. During operation in the second interface mode, the computing system may initially disable a second-mode speech command, and to respond to the guard phrase by enabling the second-mode speech command.

Description

BACKGROUND
• Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
• Computing devices such as personal computers, laptop computers, tablet computers, cellular phones, and countless types of Internet-capable devices are increasingly prevalent in numerous aspects of modern life. Over time, the manner in which these devices are providing information to users is becoming more intelligent, more efficient, more intuitive, and/or less obtrusive.
• The trend toward miniaturization of computing hardware, peripherals, as well as of sensors, detectors, and image and audio processors, among other technologies, has helped open up a field sometimes referred to as “wearable computing.” In the area of image and visual processing and production, in particular, it has become possible to consider wearable displays that place a graphic display close enough to a wearer's (or user's) eye(s) such that the displayed image appears as a normal-sized image, such as might be displayed on a traditional image display device. The relevant technology may be referred to as “near-eye displays.”
• Wearable computing devices with near-eye displays may also be referred to as “head-mountable displays” (HMDs), “head-mounted displays,” “head-mounted devices,” or “head-mountable devices.” A head-mountable display places a graphic display or displays close to one or both eyes of a wearer. To generate the images on a display, a computer processing system may be used. Such displays may occupy a wearer's entire field of view, or only occupy part of wearer's field of view. Further, head-mounted displays may vary in size, taking a smaller form such as a glasses-style display or a larger form such as a helmet, for example.
• Emerging and anticipated uses of wearable displays include applications in which users interact in real time with an augmented or virtual reality. Such applications can be mission-critical or safety-critical, such as in a public safety or aviation setting. The applications can also be recreational, such as interactive gaming. Many other applications are also possible.
SUMMARY
• An example head-mountable device (HMD) may be operable to receive and interpret voice commands. In this and other contexts, it may be desirable to disable certain voice commands until a guard phrase is detected, in order to reduce the occurrence of false-positive detections of voice commands. It may also be desirable for the HMD to support speech commands in some places within a UI, but not in others. However, it can be challenging to make such a UI simple for users to understand, such that the user knows when certain speech commands are and are not available. Accordingly, an example HMD may be configured to respond to the same guard phrase in different ways, depending upon the state the UI. In particular, an HMD may define a single, multi-modal, guard phrase, and may also define multiple interface modes that correspond to different states of the HMD's UI. The same guard phrase may therefore be used to enable a different speech command or commands in different interface modes.
• In one aspect, a device may include at least one audio sensor and a computing system configured to: (a) analyze audio data captured by the at least one audio sensor in order to detect speech that includes a predefined guard phrase and (b) operate in a plurality of different interface modes comprising at least a first and a second interface mode. During operation in the first interface mode, the computing system is configured to initially disable one or more first-mode speech commands, and to respond to detection of the guard phrase by enabling the one or more first-mode speech commands. During operation in the second interface mode, the computing system is configured to initially disable one or more second-mode speech commands, and to respond to detecting the guard phrase by enabling the one or more second-mode speech commands.
• In another aspect, a computer-implemented method may involve: (a) a computing device operating in a first interface mode, wherein, during operation in the first interface mode, the computing device initially disables one or more first-mode speech commands, and responds to detection of a guard phrase by enabling the one or more first-mode speech commands; and (b) a computing device operating in a second interface mode, wherein, during operation in the second interface mode, the computing device initially disables one or more second-mode speech commands, and responds to detection of a guard phrase by enabling the one or more second-mode speech commands.
• In a further aspect, a non-transitory computer readable medium may have stored therein instructions that are executable by a computing device to cause the computing device to perform functions comprising: (a) operating in a first interface mode, wherein the functions for operating in the first interface mode comprise initially disabling one or more first-mode speech commands, and responding to detection of a guard phrase by enabling the one or more first-mode speech commands; and (b) operating in a second interface mode, wherein the functions for operating in the second interface mode comprise initially disabling one or more second-mode speech commands, and responding to detection of a guard phrase by enabling the one or more second-mode speech commands.
• In yet a further aspect, a system may include: (a) a means for causing a computing device to operate in a first interface mode, wherein, during operation in the first interface mode, the computing device initially disables one or more first-mode speech commands and responds to detection of a guard phrase by enabling the one or more first-mode speech commands; and (b) a means for causing a computing device to operate in a second interface mode, wherein, during operation in the second interface mode, the computing device initially disables one or more second-mode speech commands and responds to detection of a guard phrase by enabling the one or more second-mode speech commands.
• These as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows screen views of a user-interface during a transition between two interface modes, according to an example embodiment.
• FIG. 2A illustrates a wearable computing system according to an example embodiment.
• FIG. 2B illustrates an alternate view of the wearable computing device illustrated inFIG. 2A.
• FIG. 2C illustrates another wearable computing system according to an example embodiment.
• FIG. 2D illustrates another wearable computing system according to an example embodiment.
• FIGS. 2E to 2G are simplified illustrations of the wearable computing system shown inFIG. 1D, being worn by a wearer.
• FIG. 3A is a simplified block diagram of a computing device according to an example embodiment.
• FIG. 3B shows a projection of an image by a head-mountable device, according to an example embodiment.
• FIGS. 4A and 4B are flow charts illustrating methods, according to example embodiments.
• FIGS. 5A to 5C illustrate applications of a multi-mode guard phrase, according to example embodiments.
DETAILED DESCRIPTION
• Example methods and systems are described herein. It should be understood that the words “example” and “exemplary” are used herein to mean “serving as an example, instance, or illustration.” Any embodiment or feature described herein as being an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or features. In the following detailed description, reference is made to the accompanying figures, which form a part thereof. In the figures, similar symbols typically identify similar components, unless context dictates otherwise. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.
• The example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
I. Overview
• A head-mountable device (HMD) may be configured to provide a voice interface, and as such, may be configured to listen for commands that are spoken by the wearer. Herein spoken commands may be referred to interchangeably as either “voice commands” or “speech commands.”
• When an HMD enables speech commands, the HMD may continuously listen for speech, so that a user can readily use the speech commands to interact with the HMD. In such case, it may be desirable to implement a “guard phrase,” which the user must recite before the speech commands are enabled. By disabling voice commands until such a guard phrase is detected, an HMD may be able to reduce the occurrence of false-positives. In other words, the HMD may be able to reduce instances where the HMD incorrectly interprets speech as including a particular speech command, and thus takes an undesired action. However, implementing such a guard phrase in a streamlined manner may be difficult, as users can perceive the need to speak a guard word before a speech command as an extra step that complicates a UI.
• Further, it may also be desirable for an HMD to support speech commands in some places within a user interface (UI), but not in others. However, it can be challenging to make such a UI simple for users to understand (e.g., so that the user knows when speech commands are and are not available). This can be further complicated by the fact that different speech commands may be needed in different places within the UI.
• According to an example embodiment, an HMD may be configured to respond to the same guard phrase in different ways, depending upon the state the UI. In particular, an HMD may define multiple interface modes that correspond to different states of the HMD's UI. Each interface mode may have a different “hotword” model that, when loaded, listens for one or more speech commands that are specific to the particular interface mode.
• In a further aspect, the HMD may define a single guard phrase to be used in multiple interface modes where speech commands are available. This guard phrase may be to be a multi-modal guard phrase, since it is used in the same way across multiple interface modes. Notably however, the actions taken by HMD in response to detecting the guard phrase are non-modal, as the HMD does not change the interface mode when the guard phrase is detected. Rather, the guard phrase may be used to enable a different speech command or commands in different interface modes (e.g., by activating the different hotword processes specified by the different interface modes).
• Configured as such, an example HMD may switch between different interface modes in order to operate in whichever interface mode corresponds to the current state of the UI (typically the interface mode that provides for speech command(s) that are useful in the current UI state). Each time the HMD switches to a different interface mode, the HMD may disable voice interaction (e.g., by unloading the previous mode's hotword process and/or refraining from loading the new mode's hotword process), and require that the user say the guard phrase in order to enable the new mode's speech commands. Then, when the HMD detects the guard phrase, the HMD enables the speech command(s) that are specific to the particular interface mode (e.g., by activating the hotword process for the interface mode).
• Additionally, in interface modes where speech commands can be enabled, the HMD may display a visual cue of the guard phrase, which can help alert a user that voice interaction can be enabled. And, once the HMD detects the guard phrase, the HMD may display a visual cue or cues that indicate the particular speech command(s) that have been enabled. By combining such visual cues with a multi-modal guard phrase, an HMD may allow for useful voice input in a manner that is more intuitive to the user.
• For example,FIG. 1 shows screen views of a UI during a transition between two interface modes in which a multi-mode guard phrase is implemented, according to an example embodiment.
• More specifically, an HMD may operate in afirst interface mode101, where one or more first-mode speech commands can be enabled by speaking a predefined guard phrase. When the HMD switches to thefirst interface mode101 from another interface mode, the HMD may initially disable the first-mode speech commands and display a visual cue for the guard phrase in its display, as shown inscreen view102. If the HMD detects the guard phrase while in the first interface mode, the HMD may enable the one or more first-mode speech commands, and display visual cues that indicate the enabled first-mode speech commands, as shown inscreen view104.
• To provide a specific example, thefirst interface mode101 may provide an interface for a home screen, which provides a launching point for a user to access a number of frequently-used features. Accordingly, when the user speaks a command to access a different feature, such as a camera or phone feature, the HMD may switch to the interface mode that provides an interface for the different feature.
• More generally, when the HMD switches to a different aspect of its UI for which one or more second-mode speech commands are supported, the HMD may switch to asecond interface mode103. When the HMD switches to thesecond interface mode103, the HMD may disable any speech commands that were enabled, and listen only for the guard phrase (e.g., by loading a guard-phrase hotword process). Further, the HMD may require the user to again speak the guard phrase before enabling the one or more second-mode speech commands.
• To provide a hint to the user that the guard word will enable voice commands, the HMD may again display the visual cue for the guard phrase, as shown inscreen106. And, if the HMD detects the guard phrase while in thesecond interface mode103, the HMD may responsively enable the one or more second-mode speech commands (e.g., by loading the hotword process for the second interface mode). When the second-mode speech commands are enabled, the HMD may display visual cues that indicate the enabled second-mode speech commands, as shown inscreen view108.
• Many implementations of a multi-mode guard phrase are possible. One implementation involves an HMD a home screen, which serves as a launch point for various different features (some or all of which may provide for voice commands), one of which may be a video camera. Thus, from the home screen, the user may say the guard phrase followed by another speech command in order to launch a camera application. Further, in some embodiments, the HMD may automatically start recording when the user launches the camera application via the home screen. During video recording, the guard phrase may be displayed to indicate that a speech command can be enabled by saying the guard word. In particular, the user may say the guard phrase followed by “stop recording” (e.g., the speech command that can be enabled in the video-recording mode), in order to stop recording video. Other implementations are also possible.
• In a further aspect, a second protective feature against false positives, in addition to the multi-mode guard phrase, may be utilized in some or all interface modes. In particular, time-out process may be implemented in order to disable the enabled speech commands if at least one of the enabled speech commands is not detected within a predetermined period of time after detection of the guard phrase. For example, in the implementation described above, a time-out process may be implemented when the guard phrase is detected while the HMD is operating in the video-recording mode. As such, when the HMD detects the guard phrase, the HMD may start a timer. Then, if the HMD does not detect the “stop recording” speech command within five seconds, for example, then the HMD may disable the “stop recording” speech command, and require the guard phrase in order to re-enable the “stop recording” speech command.
II. Example Wearable Computing Devices
• Systems and devices in which example embodiments may be implemented will now be described in greater detail. In general, an example system may be implemented in or may take the form of a wearable computer (also referred to as a wearable computing device). In an example embodiment, a wearable computer takes the form of or includes a head-mountable device (HMD).
• An example system may also be implemented in or take the form of other devices that support speech commands, such as a mobile phone, tablet computer, laptop computer, or desktop computer, among other possibilities. Further, an example system may take the form of non-transitory computer readable medium, which has program instructions stored thereon that are executable by at a processor to provide the functionality described herein. An example system may also take the form of a device such as a wearable computer or mobile phone, or a subsystem of such a device, which includes such a non-transitory computer readable medium having such program instructions stored thereon.
• An HMD may generally be any display device that is capable of being worn on the head and places a display in front of one or both eyes of the wearer. An HMD may take various forms such as a helmet or eyeglasses. As such, references to “eyeglasses” or a “glasses-style” HMD should be understood to refer to an HMD that has a glasses-like frame so that it can be worn on the head. Further, example embodiments may be implemented by or in association with an HMD with a single display or with two displays, which may be referred to as a “monocular” HMD or a “binocular” HMD, respectively.
• FIG. 2A illustrates a wearable computing system according to an example embodiment. InFIG. 2A, the wearable computing system takes the form of a head-mountable device (HMD)202 (which may also be referred to as a head-mounted display). It should be understood, however, that example systems and devices may take the form of or be implemented within or in association with other types of devices, without departing from the scope of the invention. As illustrated inFIG. 2A, theHMD202 includes frame elements including lens-frames204,206 and acenter frame support208,lens elements210,212, and extending side-arms214,216. Thecenter frame support208 and the extending side-arms214,216 are configured to secure theHMD202 to a user's face via a user's nose and ears, respectively.
• Each of theframe elements204,206, and208 and the extending side-arms214,216 may be formed of a solid structure of plastic and/or metal, or may be formed of a hollow structure of similar material so as to allow wiring and component interconnects to be internally routed through theHMD202. Other materials may be possible as well.
• One or more of each of thelens elements210,212 may be formed of any material that can suitably display a projected image or graphic. Each of thelens elements210,212 may also be sufficiently transparent to allow a user to see through the lens element. Combining these two features of the lens elements may facilitate an augmented reality or heads-up display where the projected image or graphic is superimposed over a real-world view as perceived by the user through the lens elements.
• The extending side-arms214,216 may each be projections that extend away from the lens-frames204,206, respectively, and may be positioned behind a user's ears to secure theHMD202 to the user. The extending side-arms214,216 may further secure theHMD202 to the user by extending around a rear portion of the user's head. Additionally or alternatively, for example, theHMD202 may connect to or be affixed within a head-mounted helmet structure. Other configurations for an HMD are also possible.
• TheHMD202 may also include an on-board computing system218, animage capture device220, asensor222, and a finger-operable touch pad224. The on-board computing system218 is shown to be positioned on the extending side-arm214 of theHMD202; however, the on-board computing system218 may be provided on other parts of theHMD202 or may be positioned remote from the HMD202 (e.g., the on-board computing system218 could be wire- or wirelessly-connected to the HMD202). The on-board computing system218 may include a processor and memory, for example. The on-board computing system218 may be configured to receive and analyze data from theimage capture device220 and the finger-operable touch pad224 (and possibly from other sensory devices, user interfaces, or both) and generate images for output by thelens elements210 and212.
• Theimage capture device220 may be, for example, a camera that is configured to capture still images and/or to capture video. In the illustrated configuration,image capture device220 is positioned on the extending side-arm214 of theHMD202; however, theimage capture device220 may be provided on other parts of theHMD202. Theimage capture device220 may be configured to capture images at various resolutions or at different frame rates. Many image capture devices with a small form-factor, such as the cameras used in mobile phones or webcams, for example, may be incorporated into an example of theHMD202.
• Further, althoughFIG. 2A illustrates oneimage capture device220, more image capture device may be used, and each may be configured to capture the same view, or to capture different views. For example, theimage capture device220 may be forward facing to capture at least a portion of the real-world view perceived by the user. This forward facing image captured by theimage capture device220 may then be used to generate an augmented reality where computer generated images appear to interact with or overlay the real-world view perceived by the user.
• Thesensor222 is shown on the extending side-arm216 of theHMD202; however, thesensor222 may be positioned on other parts of theHMD202. For illustrative purposes, only onesensor222 is shown. However, in an example embodiment, theHMD202 may include multiple sensors. For example, anHMD202 may includesensors202 such as one or more gyroscopes, one or more accelerometers, one or more magnetometers, one or more light sensors, one or more infrared sensors, and/or one or more microphones. Other sensing devices may be included in addition or in the alternative to the sensors that are specifically identified herein.
• The finger-operable touch pad224 is shown on the extending side-arm214 of theHMD202. However, the finger-operable touch pad224 may be positioned on other parts of theHMD202. Also, more than one finger-operable touch pad may be present on theHMD202. The finger-operable touch pad224 may be used by a user to input commands. The finger-operable touch pad224 may sense at least one of a pressure, position and/or a movement of one or more fingers via capacitive sensing, resistance sensing, or a surface acoustic wave process, among other possibilities. The finger-operable touch pad224 may be capable of sensing movement of one or more fingers simultaneously, in addition to sensing movement in a direction parallel or planar to the pad surface, in a direction normal to the pad surface, or both, and may also be capable of sensing a level of pressure applied to the touch pad surface. In some embodiments, the finger-operable touch pad224 may be formed of one or more translucent or transparent insulating layers and one or more translucent or transparent conducting layers. Edges of the finger-operable touch pad224 may be formed to have a raised, indented, or roughened surface, so as to provide tactile feedback to a user when the user's finger reaches the edge, or other area, of the finger-operable touch pad224. If more than one finger-operable touch pad is present, each finger-operable touch pad may be operated independently, and may provide a different function.
• In a further aspect,HMD202 may be configured to receive user input in various ways, in addition or in the alternative to user input received via finger-operable touch pad224. For example, on-board computing system218 may implement a speech-to-text process and utilize a syntax that maps certain spoken commands to certain actions. In addition,HMD202 may include one or more microphones via which a wearer's speech may be captured. Configured as such,HMD202 may be operable to detect spoken commands and carry out various computing functions that correspond to the spoken commands.
• As another example,HMD202 may interpret certain head-movements as user input. For example, whenHMD202 is worn,HMD202 may use one or more gyroscopes and/or one or more accelerometers to detect head movement. TheHMD202 may then interpret certain head-movements as being user input, such as nodding, or looking up, down, left, or right. AnHMD202 could also pan or scroll through graphics in a display according to movement. Other types of actions may also be mapped to head movement.
• As yet another example,HMD202 may interpret certain gestures (e.g., by a wearer's hand or hands) as user input. For example,HMD202 may capture hand movements by analyzing image data fromimage capture device220, and initiate actions that are defined as corresponding to certain hand movements.
• As a further example,HMD202 may interpret eye movement as user input. In particular,HMD202 may include one or more inward-facing image capture devices and/or one or more other inward-facing sensors (not shown) that may be used to track eye movements and/or determine the direction of a wearer's gaze. As such, certain eye movements may be mapped to certain actions. For example, certain actions may be defined as corresponding to movement of the eye in a certain direction, a blink, and/or a wink, among other possibilities.
• HMD202 also includes aspeaker225 for generating audio output. In one example, the speaker could be in the form of a bone conduction speaker, also referred to as a bone conduction transducer (BCT).Speaker225 may be, for example, a vibration transducer or an electroacoustic transducer that produces sound in response to an electrical audio signal input. The frame ofHMD202 may be designed such that when a user wearsHMD202, thespeaker225 contacts the wearer. Alternatively,speaker225 may be embedded within the frame ofHMD202 and positioned such that, when theHMD202 is worn,speaker225 vibrates a portion of the frame that contacts the wearer. In either case,HMD202 may be configured to send an audio signal tospeaker225, so that vibration of the speaker may be directly or indirectly transferred to the bone structure of the wearer. When the vibrations travel through the bone structure to the bones in the middle ear of the wearer, the wearer can interpret the vibrations provided byBCT225 as sounds.
• Various types of bone-conduction transducers (BCTs) may be implemented, depending upon the particular implementation. Generally, any component that is arranged to vibrate theHMD202 may be incorporated as a vibration transducer. Yet further it should be understood that anHMD202 may include asingle speaker225 or multiple speakers. In addition, the location(s) of speaker(s) on the HMD may vary, depending upon the implementation. For example, a speaker may be located proximate to a wearer's temple (as shown), behind the wearer's ear, proximate to the wearer's nose, and/or at any other location where thespeaker225 can vibrate the wearer's bone structure.
• FIG. 2B illustrates an alternate view of the wearable computing device illustrated inFIG. 2A. As shown inFIG. 2B, thelens elements210,212 may act as display elements. TheHMD202 may include afirst projector228 coupled to an inside surface of the extending side-arm216 and configured to project adisplay230 onto an inside surface of thelens element212. Additionally or alternatively, asecond projector232 may be coupled to an inside surface of the extending side-arm214 and configured to project adisplay234 onto an inside surface of thelens element210.
• Thelens elements210,212 may act as a combiner in a light projection system and may include a coating that reflects the light projected onto them from theprojectors228,232. In some embodiments, a reflective coating may not be used (e.g., when theprojectors228,232 are scanning laser devices).
• In alternative embodiments, other types of display elements may also be used. For example, thelens elements210,212 themselves may include: a transparent or semi-transparent matrix display, such as an electroluminescent display or a liquid crystal display, one or more waveguides for delivering an image to the user's eyes, or other optical elements capable of delivering an in focus near-to-eye image to the user. A corresponding display driver may be disposed within theframe elements204,206 for driving such a matrix display. Alternatively or additionally, a laser or LED source and scanning system could be used to draw a raster display directly onto the retina of one or more of the user's eyes. Other possibilities exist as well.
• FIG. 2C illustrates another wearable computing system according to an example embodiment, which takes the form of anHMD252. TheHMD252 may include frame elements and side-arms such as those described with respect toFIGS. 2A and 2B. TheHMD252 may additionally include an on-board computing system254 and animage capture device256, such as those described with respect toFIGS. 2A and 2B. Theimage capture device256 is shown mounted on a frame of theHMD252. However, theimage capture device256 may be mounted at other positions as well.
• As shown inFIG. 2C, theHMD252 may include asingle display258 which may be coupled to the device. Thedisplay258 may be formed on one of the lens elements of theHMD252, such as a lens element described with respect toFIGS. 2A and 2B, and may be configured to overlay computer-generated graphics in the user's view of the physical world. Thedisplay258 is shown to be provided in a center of a lens of theHMD252, however, thedisplay258 may be provided in other positions, such as for example towards either the upper or lower portions of the wearer's field of view. Thedisplay258 is controllable via thecomputing system254 that is coupled to thedisplay258 via anoptical waveguide260.
• FIG. 2D illustrates another wearable computing system according to an example embodiment, which takes the form of amonocular HMD272. TheHMD272 may include side-arms273, acenter frame support274, and a bridge portion withnosepiece275. In the example shown inFIG. 2D, thecenter frame support274 connects the side-arms273. TheHMD272 does not include lens-frames containing lens elements. TheHMD272 may additionally include acomponent housing276, which may include an on-board computing system (not shown), animage capture device278, and abutton279 for operating the image capture device278 (and/or usable for other purposes).Component housing276 may also include other electrical components and/or may be electrically connected to electrical components at other locations within or on the HMD.HMD272 also includes aBCT286.
• TheHMD272 may include asingle display280, which may be coupled to one of the side-arms273 via thecomponent housing276. In an example embodiment, thedisplay280 may be a see-through display, which is made of glass and/or another transparent or translucent material, such that the wearer can see their environment through thedisplay280. Further, thecomponent housing276 may include the light sources (not shown) for thedisplay280 and/or optical elements (not shown) to direct light from the light sources to thedisplay280. As such,display280 may include optical features that direct light that is generated by such light sources towards the wearer's eye, whenHMD272 is being worn.
• In a further aspect,HMD272 may include a slidingfeature284, which may be used to adjust the length of the side-arms273. Thus, slidingfeature284 may be used to adjust the fit ofHMD272. Further, an HMD may include other features that allow a wearer to adjust the fit of the HMD, without departing from the scope of the invention.
• FIGS. 2E to 2G are simplified illustrations of theHMD272 shown inFIG. 2D, being worn by awearer290. As shown inFIG. 2F, whenHMD272 is worn,BCT286 is arranged such that whenHMD272 is worn,BCT286 is located behind the wearer's ear. As such,BCT286 is not visible from the perspective shown inFIG. 2E.
• In the illustrated example, thedisplay280 may be arranged such that whenHMD272 is worn,display280 is positioned in front of or proximate to a user's eye when theHMD272 is worn by a user. For example,display280 may be positioned below the center frame support and above the center of the wearer's eye, as shown inFIG. 2E. Further, in the illustrated configuration,display280 may be offset from the center of the wearer's eye (e.g., so that the center ofdisplay280 is positioned to the right and above of the center of the wearer's eye, from the wearer's perspective).
• Configured as shown inFIGS. 2E to 2G,display280 may be located in the periphery of the field of view of thewearer290, whenHMD272 is worn. Thus, as shown byFIG. 2F, when thewearer290 looks forward, thewearer290 may see thedisplay280 with their peripheral vision. As a result,display280 may be outside the central portion of the wearer's field of view when their eye is facing forward, as it commonly is for many day-to-day activities. Such positioning can facilitate unobstructed eye-to-eye conversations with others, as well as generally providing unobstructed viewing and perception of the world within the central portion of the wearer's field of view. Further, when thedisplay280 is located as shown, thewearer290 may view thedisplay280 by, e.g., looking up with their eyes only (possibly without moving their head). This is illustrated as shown inFIG. 2G, where the wearer has moved their eyes to look up and align their line of sight withdisplay280. A wearer might also use the display by tilting their head down and aligning their eye with thedisplay280.
• FIG. 3A is a simplified block diagram acomputing device310 according to an example embodiment. In an example embodiment,device310 communicates using a communication link320 (e.g., a wired or wireless connection) to aremote device330. Thedevice310 may be any type of device that can receive data and display information corresponding to or associated with the data. For example, thedevice310 may take the form of or include a head-mountable display, such as the head-mounteddevices202,252, or272 that are described with reference toFIGS. 2A to 2G.
• Thedevice310 may include aprocessor314 and adisplay316. Thedisplay316 may be, for example, an optical see-through display, an optical see-around display, or a video see-through display. Theprocessor314 may receive data from theremote device330, and configure the data for display on thedisplay316. Theprocessor314 may be any type of processor, such as a micro-processor or a digital signal processor, for example.
• Thedevice310 may further include on-board data storage, such asmemory318 coupled to theprocessor314. Thememory318 may store software that can be accessed and executed by theprocessor314, for example.
• Theremote device330 may be any type of computing device or transmitter including a laptop computer, a mobile telephone, head-mountable display, tablet computing device, etc., that is configured to transmit data to thedevice310. Theremote device330 and thedevice310 may contain hardware to enable thecommunication link320, such as processors, transmitters, receivers, antennas, etc.
• Further,remote device330 may take the form of or be implemented in a computing system that is in communication with and configured to perform functions on behalf of client device, such ascomputing device310. Such aremote device330 may receive data from another computing device310 (e.g., anHMD202,252, or272 or a mobile phone), perform certain processing functions on behalf of thedevice310, and then send the resulting data back todevice310. This functionality may be referred to as “cloud” computing.
• InFIG. 3A, thecommunication link320 is illustrated as a wireless connection; however, wired connections may also be used. For example, thecommunication link320 may be a wired serial bus such as a universal serial bus or a parallel bus. A wired connection may be a proprietary connection as well. Thecommunication link320 may also be a wireless connection using, e.g., Bluetooth® radio technology, communication protocols described in IEEE 802.11 (including any IEEE 802.11 revisions), Cellular technology (such as GSM, CDMA, UMTS, EV-DO, WiMAX, or LTE), or Zigbee® technology, among other possibilities. Theremote device330 may be accessible via the Internet and may include a computing cluster associated with a particular web service (e.g., social-networking, photo sharing, address book, etc.).
• FIG. 3B shows an example projection of UI elements described herein via animage380 by an example head-mountable device (HMD)352, according to an example embodiment. Other configurations of an HMD may be also be used to present the UI described herein viaimage380.FIG. 3B showswearer354 ofHMD352 looking at an eye ofperson356. As such,wearer354′s gaze, or direction of viewing, is alonggaze vector360. A horizontal plane, such ashorizontal gaze plane364 can then be used to divide space into three portions: space abovehorizontal gaze plane364, space inhorizontal gaze plane364, and space belowhorizontal gaze plane364. In the context ofprojection plane376,horizontal gaze plane360 appears as a line that divides projection plane into a subplane above the line ofhorizontal gaze plane360, a subplane a subspace below the line ofhorizontal gaze plane360, and the line wherehorizontal gaze plane360 intersectsprojection plane376. InFIG. 3B,horizontal gaze plane364 is shown using dotted lines.
• Additionally, a dividing plane, indicated usingdividing line374 can be drawn to separate space into three other portions: space to the left of the dividing plane, space on the dividing plane, and space to right of the dividing plane. In the context ofprojection plane376, the dividing plane intersectsprojection plane376 at dividingline374. Thus the dividing plane divides projection plane into: a subplane to the left of dividingline374, a subplane to the right of dividingline374, and dividingline374. InFIG. 3B, dividingline374 is shown as a solid line.
• Humans, such aswearer354, when gazing in a gaze direction, may have limits on what objects can be seen above and below the gaze direction.FIG. 3B shows the uppervisual plane370 as the uppermost plane thatwearer354 can see while gazing alonggaze vector360, and shows lowervisual plane372 as the lowermost plane thatwearer354 can see while gazing alonggaze vector360. InFIG. 3B, uppervisual plane370 and lowervisual plane372 are shown using dashed lines.
• The HMD can project an image for view bywearer354 at someapparent distance362 alongdisplay line382, which is shown as a dotted and dashed line inFIG. 3B. For example,apparent distance362 can be1 meter, four feet, infinity, or some other distance. That is,HMD352 can generate a display, such asimage380, which appears to be at theapparent distance362 from the eye ofwearer354 and inprojection plane376. In this example,image380 is shown betweenhorizontal gaze plane364 and uppervisual plane370; that isimage380 is projected abovegaze vector360. In this example,image380 is also projected to the right of dividingline374. Asimage380 is projected above and to the right ofgaze vector360,wearer354 can look atperson356 withoutimage380 obscuring their general view. In one example, the display element of theHMD352 is translucent when not active (i.e. whenimage380 is not being displayed), and so thewearer354 can perceive objects in the real world along the vector ofdisplay line382.
• Other example locations for displayingimage380 can be used to permitwearer354 to look alonggaze vector360 without obscuring the view of objects along the gaze vector. For example, in some embodiments,image380 can be projected abovehorizontal gaze plane364 near and/or just above uppervisual plane370 to keepimage380 from obscuring most ofwearer354′s view. Then, whenwearer354 wants to viewimage380,wearer354 can move their eyes such that their gaze is directly towardimage380.
III. Illustrative Methods
• FIG. 4A is a flow chart illustrating amethod400, according to an example embodiment. Some functions of the method may be implemented while an HMD is operating infirst interface mode402, while other functions may be implemented while an HMD is operating insecond interface mode404.
• Referring again toFIG. 4A,method400 involves a computing device, such as an HMD or component thereof, operating in afirst interface mode402. Operation in thefirst interface mode402 involves initially disabling one or more first-mode speech commands, as shown byblock406. Further, the HMD may listen for a guard phrase, as shown byblock408. If the guard phrase is detected, then the HMD responds by enabling the one or more first-mode speech commands, as shown byblock410. However, as long the guard phrase is not detected, the HMD the first-mode speech commands remain disabled.
• At a different point in time,method400 involves operating in thesecond interface mode404, instead of thefirst interface mode402. Operation in thesecond interface mode404 involves initially disabling one or more second-mode speech commands as shown byblock412. Further, in thesecond interface mode404, the HMD may listen for the same guard phrase as the HMD listened for in thefirst interface mode402, as shown byblock414. If the guard phrase is detected, then the HMD may respond by enabling the second-mode speech command, as shown byblock416. However, as long the guard phrase is not detected, the second-mode speech command remains disabled.
• In the illustrated embodiment, the HMD can switch directly back and forth between thefirst interface mode402 and thesecond interface mode404. It should be understood, however, that it is possible for the HMD to necessarily or optionally switch to one or more other interface modes in order to reach thesecond interface mode404 from thefirst interface mode402, and vice versa. Further, the HMD may switch between thefirst interface mode402 and one or more other interface modes, and/or may switch between thesecond interface mode404 and one or more other interface modes.
• Herein, an interface mode may specify a certain way of interpreting input data received via user-input interfaces, such as microphone(s), touchpad(s) or touchscreen(s), sensor(s) arranged to detect gestures in the air, sensors arranged to provide data indicative of head movement (e.g., accelerometer(s), gyroscope(s), and/or magnetometers), an eye-tracking or gaze-tracking system configured to detect eye gestures and/or movement (e.g., winks, blinks, and/or directional movements of the eye), a keyboard, and/or a mouse, among other possibilities. A particular interface mode may also correspond to particular way of receiving input data and/or assisting the user in providing input data that is appropriate for the mode, such as a graphical user-interface (GUI) that is designed to receive certain types of input data and/or to suggest what input data and/or operations are possible in the interface mode.
• In an example embodiment, a given interface mode may specify certain voice commands that are available while in the given interface mode. A voice command that is available in a certain interface mode may or may not be immediately usable when the HMD switches to the interface mode. In particular, when an HMD switches to a new interface mode, an available voice command for the interface mode may, by default, be disabled. Accordingly, the user may be required to enable the voice command. In an example embodiment, at least the first and second interface modes each specify voice commands that can be enabled in the respective mode. However, there may be other interface modes that do not provide for any voice commands. Alternatively, in some embodiments, there may be voice commands available in every interface mode of the HMD.
• To implement an interface mode in which voice commands are available, an HMD may utilize “hotword” models. A hotword process may be program logic that is executed to listen for certain voice or speech commands in an incoming audio stream. Accordingly, when the HMD begins operating in thefirst interface mode402, the HMD may load a hotword process for the guard phrase in order to listen for a guard phrase. Then, when the HMD detects the guard phrase (e.g., at block408), the HMD may responsively load a hotword process or models for the one or more first-mode speech commands (e.g., at block410). Note that in some cases, there may be a single hotword process for each speech command. In other cases, a single hotword process may be loaded to listen for two or more speech commands.
• In a further aspect, there may be a particular speech command or another type of user command that allows the user to switch from the portion of the UI associated with the first interface mode to the portion of the UI associated with the second interface mode. For example, during operation in thefirst interface mode402, the HMD may detect the guard phrase followed by one of the first-mode speech commands and responsively switch to thesecond interface mode404. In some implementations, thefirst interface mode402 may correspond to a home-screen interface, and the one or more first-mode speech commands may correspond to one or more actions that can be initiated via the home-screen interface. Further, one of the one or more first-mode speech commands may be a speech command that can be spoken to start recording a video. As such, to cause the HMD to start recording a video, the user may say the guard phrase followed by the speech command that starts recording the video.
• FIG. 4B is a flow chart illustrating anothermethod450, according to an example embodiment.Method450 is an embodiment ofmethod400 in which hotword processes are used to detect the multi-mode guard phrase and mode-specific speech commands in the first andsecond interface modes482 and484. Further, in method450 a time-out process is added to thesecond interface mode484 as an additional protection against false-positive detections of speech commands.
• Referring toFIG. 4B in greater detail, when an HMD begins operating in thefirst interface mode482, the HMD enables a hotword process for the guard phrase (if it is disabled at the time), and disables the hotword process for the first-mode speech commands (if it is enabled at the time), as shown byblock452. The hotword process for the guard phrase is then used to listen for the guard phrase, as shown byblock454. If the guard phrase is detected, then the HMD enables the hotword process for one or more first-mode speech commands, as shown byblock456. The hotword process for the one or more first-mode speech commands is then used to listen for these speech commands, as shown byblock458.
• In the illustrated embodiment, the first-mode speech commands include one speech command that launches a process and/or UI that corresponds to thesecond interface mode484. When this particular first-mode speech command is detected, the HMD transitions to thesecond interface mode484, as represented by the arrow fromblock458 to block460. Note that while transitions to other interface modes are not shown inFIG. 4B, an HMD might also be configured to transition to other interface modes in response to detecting other first-mode speech commands.
• When the HMD begins operating in thesecond interface mode484, the HMD enables the hotword process for the guard phrase (if it not already enabled at the time), and disables the hotword process for the second-mode speech command (if it is enabled at the time), as shown byblock460. The hotword process for the guard phrase is again used to listen for the guard phrase, as shown byblock462. If the guard phrase is detected, then the HMD enables the hotword process for the second-mode speech command, as shown byblock464. The hotword process for the second-mode speech command is then used to listen for this speech command, as shown byblock464.
• In a further aspect of thesecond interface mode484, when the HMD detects the guard phrase, the HMD may also implement a time-out process in an effort to further protect against false-positives. For example, at or near when the HMD detects the guard phrase, the HMD may start a timer. Accordingly, the HMD may then continue to listen for the second-mode speech command, atblock466, for the duration of the timer (which may also be referred to as the “timeout period”). If the HMD detects the second-mode speech command before the timeout period elapses, the HMD initiates a process corresponding to the second-mode speech command, as shown byblock470. However, if the second-mode speech command has not been detected, and the HMD determines atblock468 that the timeout period has elapsed, then the HMD repeatsblock460 in order to enable the hotword process for the guard phrase (if it not already enabled at the time), and disable the hotword process for the second-mode speech command.
• Note that in an example embodiment, there may only be one hotword process for speech commands available at a given point in time (i.e., the hotword process for speech commands that are available in the current interface). In such an embodiment, the hotword process for the first-mode speech commands will already be disabled when the HMD switches to the first-interface mode from another interface mode. Thus, if the hotword process for the first-mode speech commands is already disabled when the HMD carries outblock452, then the HMD may not need to take any action to disable the hotword process for the first-mode speech commands. Similarly, if the hotword process for the second-mode speech commands is already disabled when the HMD carries outblock460, then the HMD may not need to take any action to disable the hotword process for the second-mode speech commands.
• Further, in some embodiments, the HMD may enable the hotword process for the guard phrase so long as some speech commands are available in whichever interface mode the HMD is operating in. Accordingly, the hotword process for the guard phrase may remain enabled as the HMD switches between interface modes where voice commands are provided. For instance, the hotword process for the guard phrase may be enabled in thefirst interface mode482, and may remain when the HMD switches from thefirst interface mode482 to thesecond interface mode484. Thus, if the hotword process for the guard phrase is already enabled when the HMD carries outblock452 and/or block460, then the HMD may not need to take any action to enable the hotword process for the guard phrase.
• In some embodiments, the hotword process for guard phrase may be kept enabled after guard phrase detected, at same time as hotword process for speech commands is enabled (or alternatively hotword process for speech commands may simply include guard phrase and speech commands). Further in some cases, the hotword process for the guard phrase may be permanently loaded, such that the HMD is always listening for the guard phrase. Alternatively, the HMD may disable the hotword process for the guard phrase when the hotword process for speech commands is enabled and/or at other times when the HMD does not need to listen for the guard phrase (e.g., when the HMD is operating in an interface mode where no speech commands are available and/or where available speech commands are always enabled).
• In a further aspect, an HMD may also provide visual cues for a voice UI. As such, when the hotword process for the guard phrase is enabled, such as atblock452 or block460,method450 may further involve the HMD displaying a visual cue that is indicative of the guard phrase. Additionally or alternatively, after the guard phrase is detected in a given interface mode,method450 may further involve the HMD displaying one or more visual cues corresponding to the one or more speech commands that have been enabled. For example, atblock456, the HMD may display visual cues that correspond to the first-mode speech commands, and atblock464, the HMD may display a visual cue that corresponds to the second-mode speech commands. Other examples are also possible.
• Note that inmethod450, thesecond interface mode484 uses the guard phrase to protect a single voice command. In some ways, this may be regarded as counterintuitive, as it might be perceived as an extra step that could annoy a user. However, as will be described below in greater detail, a carefully chosen guard command may alleviate the perception of a guard phrase as an extra step. More specifically, in some embodiments, the guard phrase may be selected such that a user may perceive the guard phrase and a subsequent speech command as a single command, even though the HMD is detecting them separately.
IV. Illustrative Device Functionality
• FIGS. 5A to 5C illustrate applications of a multi-mode guard phrase, according to example embodiments. In order to provide a voice UI with a multi-mode guard phrase, these applications may utilize methods such as those described in reference toFIGS. 4A and 4B. However, other techniques may also be used to provide the UI functionality shown inFIGS. 5A to 5C.
• FIG. 5A shows an application that involves a home-screen interface501 and a voice-recording interface503. More specifically, an HMD may operate in a home-screen mode501, where certain speech commands can be enabled by saying the guard phrase “ok glass.” This may be implemented by loading a hotword process that listens only for the phrase “ok glass.” While in the home-screen mode501, the HMD may display “ok glass” as a visual cue that the guard phrase can be used to enable speech interaction, as shown byscreen view500.
• When the HMD detects that the wearer has said “ok glass,” the HMD may enable the speech commands for the home-screen mode501. To do so, the HMD may load a hotword process that listens for the speech commands that are useful in home-screen mode501. Further, the HMD may display visual cues indicating the speech commands that have been enabled. For example, as shown byscreen view502, the HMD may display visual cues corresponding to speech commands, such as “navigate to”, “take a photo”, “record a video”, “send message to”, etc.
• After enabling the speech commands in home-screen mode501, the HMD may switch to a different interface mode in response to one of the speech commands. For instance, as shown inFIG. 5A, if the user says “record a video,” the HMD may switch from home-screen mode501 to a video-recording mode503. Further, in some embodiments, different speech commands could be used to initiate different functions and/or launch other applications, which may each have their own corresponding interface mode. As examples, a “send message to” command could switch to a text-message or e-mail interface mode, and a “make a call” command could switch to a phone-call interface mode. Other examples are also possible.
• When the HMD switches to video-recording mode503, the HMD may launch a camera application and automatically start recording video. Further, a hotword process for video-recording mode503 may provide for a single speech command to stop the video recording, which is also guarded by the “ok glass” guard phrase. To indicate that a speech command can be enabled, the HMD may display a visual cue. For example, inscreen view504, the HMD displays the guard phrase, “ok glass,” to indicate that the user can enable voice interaction by saying “ok glass.” Other examples are also possible.
• When the HMD is in video-recording mode503, and detects that the wearer has said “ok glass,” the HMD may enable the hotword process that listens for the single speech command that is available in the video-recording mode503; e.g., a “stop recording” speech command. Further, the HMD may provide a visual cue that the “stop recording” speech command can be used. For example, the HMD may update the display so that “stop recording” follows “ok glass,” as shown byscreen view506. The wearer can then say “stop recording” to cause the camera application to cease recording video (as shown inscreen view508, where an indicator in the lower right may stop blinking to indicate that video is not being captured).
• As noted above, some interface modes may provide an additional guard against false-positive detection of speech commands by utilizing a timeout process to disable speech command(s) when no speech command is detected within a certain period of time after detecting the guard phrase. Further, the implementation of a time-out process may vary between modes.
• For instance, consider the example inFIG. 5A with a home-screen mode and a video-recording mode. It might be the case that users typically go to the home screen with a specific task in mind, and thus are only there for a short time (e.g.,15 seconds or less). However, it might also be the case that users typically record video for a longer period of time (e.g.,1 to10 minutes). If a user typically stays on the home screen for less time than the user spends recording a video, the probability of incorrectly concluding the user has said “ok glass” while at the home screen may be less than the probability of such a false positive while recording video. Accordingly, a shorter time-out period may be implemented in the video-recording mode (e.g.,5 seconds) and a longer time-out period (or possibly no time-out period) may be implemented in the home-screen mode.
• In yet a further aspect, the visual cues for the same guard phrase may vary between interface modes. Additionally or alternatively, the visual cues for enabled speech commands may be formatted for display in different ways, depending upon the particular interface mode. For instance, a home screen may serve as a launch point to get to other modes, and thus it may be acceptable for visual cues to be displayed such that they take up more space and/or are more central in the HMD wearer's field of view. During video recording, however, it may be desirable for the visual cues to be less obtrusive, so that the wearer can see through the display to their environment. In particular, since the HMD may not have an actual viewfinder for a point-of-view (POV) camera, the wearer may assume that there field of view is roughly what the POV is capturing on video, which makes an obstructed view through the viewfinder desirable.
• Thus, in home-screen mode501, the “ok glass” visual cue may be larger and centrally placed, as shown inscreen view500. Further, the visual cues for speech commands shown inscreen view502 are displayed in a menu form that occupies a significant amount of the display. In video-recording mode503, however, the visual cues for “ok glass” guard phrase and the “stop recording” speech command are smaller and displayed at the lower edge of the display, as shown in screen views504 and506. (Note that the locations may vary; for instance, the visual cues for the “ok glass” guard phrase and the “stop recording” could also be displayed at the upper edge of the display, or elsewhere.)
• Note that if the user thinks of “glass” as the name or type of their device, then the phrase “ok glass” may be a particularly good choice for a guard phrase. In particular, the phrase “ok glass” may feel like something the user would say in order to address the device, in the same manner as they might address a person to whom they are speaking. As such, while the computing device may treat the guard phrase and a subsequent speech commands as separate voice commands, the combination of the guard phrase and a speech command may feel to the user like a single command in which they address their computing device and tell the device what they want it to do. For instance, in the home-screen mode501, the user may say “ok glass, record a video,” which may feel to the user like a single voice command, even though the hotword process to detect “record a video” is not loaded until the user says “ok glass.” Thus, with the use of a guard phrase such as “ok glass,” the user may not even be aware that the guard phrase is required, or at least may find the need to say a guard phrase less cumbersome.
• Other guard phrases may enhance the user experience in a similar way as “ok glass” can. Generally, any guard phrase that a user may perceive as addressing or conversing with their device could similarly enhance the user experience. For example, a guard phrase that includes a name for the device, which may be predefined or created by the user, may have a similar effect on the user experience. Other examples are also possible.
• In a further aspect, an example computing device may be configured to remove a guard phrase, such as “ok glass”, and/or to remove a “stop recording” speech command, from the audio portion of a video. More specifically, when a user says “ok glass, stop recording,” or something to that effect, in order to stop recording a video, the audio portion of the video may include the speech command. However, in many instances, the user may not want the speech command to be included in the audio. Accordingly, an HMD may be configured to at least partially remove the guard phrase and/or the stop-recording command from the audio portion of a captured video.
• The HMD may use various techniques in an effort to remove the guard phrase and/or the stop-recording command from the audio portion of a captured video. For example, the HMD could simply trim the portion of the video that includes the guard phrase and/or the stop-recording command. The HMD could also trim just the audio, without trimming the entire video (e.g., so that the video is silent during the time when the user says the guard phrase and/or the stop-recording command).
• As another example, the HMD could use a technique such as spectral subtraction to remove the guard phrase and/or the stop-recording command from the video, without trimming the audio. For example, the HMD may store a previous instance or instances when the user says the guard phrase and/or the stop-recording command, and create a model speech signals for the guard phrase and/or the stop-recording command. The HMD may then subtract the model speech signals from the audio portion of a video to at least partially remove the guard phrase and/or the stop-recording command from the audio (while hopefully leaving a significant portion of other audio intact). Other techniques are also possible.
• Many other interface modes with guard-phrase protected speech commands are possible. For example,FIG. 5B shows an application that involves an incoming-call mode511 and anotherinterface mode513. In some cases, theother interface mode513 may be the home-screen mode501 described in reference toFIG. 5A; but in other cases, it could be a different interface mode. In any case, when the HMD is operating in theother interface mode513 and receives an incoming call, the HMD may responsively switch to incoming-call mode511.
• There may be one or more speech commands available in the incoming-call mode511, which can be enabled via the “ok glass” guard phrase. To indicate that a speech command can be enabled, the HMD may display visual cue. Thus, in the illustrated example, the HMD displays the guard phrase “ok glass,” as shown byscreen view510. When the HMD detects speech that includes “ok glass,” the HMD may display visual cues to indicate the particular speech commands that have been enabled. For example, in the illustrated embodiment, the HMD display visual cues indicating that the speech commands “answer call,” “send to voicemail,” and “send busy message,” can be utilized, as shown byscreen view512.
• FIG. 5C provides another example of an interface mode with guard-phrase protected speech commands. In particular,FIG. 5C shows an application that involves an incoming-message mode521 and anotherinterface mode523. In some cases, theother interface mode523 may be the home-screen mode501 described in reference toFIG. 5A; but in other cases, it could be a different interface mode. In any case, when the HMD is operating in theother interface mode523 and receives an incoming message, such as a text message or an e-mail, the HMD may responsively switch to incoming-message mode521.
• There may be one or more speech commands available in the incoming-message mode521, which can be enabled via the “ok glass” guard phrase. To indicate that the one or more speech commands can be enabled, the HMD may display one or more visual cues. Thus, in the illustrated example, the HMD displays the guard phrase “ok glass,” as shown byscreen view520. Then, when the HMD detects speech that includes “ok glass,” the HMD may display visual cues to indicate the particular speech commands that have been enabled. In the illustrated embodiment, the HMD display visual cues indicating that the speech commands “show the message,” “reply to the message,” and “delete the message,” can be utilized, as shown byscreen view522.
V. Conclusion
• While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims (20)

We claim:

1. A method implemented by one or more processors of a computing device, the method comprising:

transitioning the computing device into a given interface mode in response to receiving sensor data captured by at least one sensor of the computing device;

in response to the computing device being in the given interface mode:

activating one or more speech commands that are specific to the given interface mode,

wherein the given interface mode corresponds to a current state of a user interface of the computing device, and

wherein the given interface mode is one of multiple interface modes each corresponding to corresponding alternate states of the user interface;

while the computing device is in the given interface mode and while the one or more speech commands are activated:

receiving audio data captured by at least one audio sensor of the computing device;

analyzing, based on the one or more speech commands being activated, the audio data to determine whether any of the one or more speech commands are included in the audio data;

in response to determining a given speech command, of the one or more speech commands, is included in the audio data without a predefined guard phrase, and in response to determining that the audio data is received within a predetermined period of time of transitioning the computing device into the given interface mode:

performing one or more actions, via the computing device, that correspond to the given speech command.

2. The method ofclaim 1, further comprising:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

determining the predetermined period of time has lapsed; and

in response to determining the predetermined period of time has lapsed,

deactivating one or more of the speech commands that are specific to the given interface mode.

3. The method ofclaim 2, further comprising:

while the computing device is in the given interface mode and while the one or more speech commands are deactivated:

in response to determining the given speech command, of the one or more speech commands, is included in the audio data without the predefined guard phrase, and in response to determining that the audio data is not received within the predetermined period of time:

refraining from performing one or more of the actions, via the computing device, that correspond to the given speech command.

4. The method ofclaim 3, further comprising:

subsequent to refraining from performing one or more of the actions, via the computing device, that correspond to the given speech command:

receiving additional audio data captured by the at least one audio sensor of the computing device, the additional audio data including at least the predefined guard phrase; and

re-activating one or more speech of the commands that are specific to the given interface mode.

5. The method ofclaim 1, further comprising:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

displaying a visual cue for one or more of the speech commands via a display of the computing device.

6. The method ofclaim 5, further comprising:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

determining the predetermined period of time has lapsed; and

in response to determining the predetermined period of time has lapsed, causing the visual cue for the one or more speech commands to be removed from the display of the computing device.

7. The method ofclaim 1,

wherein activating the one or more speech commands that are specific to the given interface mode comprises loading, at the computing device, at least one hotword process for the one or more speech commands; and

wherein analyzing, based on the one or more speech commands being activated, the audio data to determine whether any of the one or more speech commands are included in the audio data comprises:

analyzing the audio data using the at least one hotword process.

8. The method ofclaim 1, wherein the sensor data captured by the at least one sensor of the computing device comprises preceding audio data captured by the at least one audio sensor of the computing device, the preceding audio data including at least the predefined guard phrase and an indication of the given interface mode.

9. The method ofclaim 1, wherein the predetermined period of time is specific to the given interface mode.

10. The method ofclaim 1, wherein activating one or more of the speech commands in based on the first audio data.

11. The method ofclaim 1, wherein the computing device is a head-mountable device.

12. A computing device including memory and one or more processors configured to execute instructions stored in memory, the instructions comprising instructions to:

transition the computing device into a given interface mode in response to receiving sensor data captured by at least one sensor of the computing device;

in response to the computing device being in the given interface mode:

activate one or more speech commands that are specific to the given interface mode,

wherein the given interface mode corresponds to a current state of a user

interface of the computing device, and

wherein the given interface mode is one of multiple interface modes each corresponding to corresponding alternate states of the user interface;

while the computing device is in the given interface mode and while the one or more speech commands are activated:

receive audio data captured by at least one audio sensor of the computing device;

analyze, based on the one or more speech commands being activated, the audio data to determine whether any of the one or more speech commands are included in the audio data;

in response to determining a given speech command, of the one or more speech commands, is included in the audio data without a predefined guard phrase, and in response to determining that the audio data is received within a predetermined period of time of transitioning the computing device into the given interface mode:

perform one or more actions, via the computing device, that correspond to the given speech command.

13. The computing device ofclaim 12, wherein the instructions further comprise instructions to:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

determine the predetermined period of time has lapsed; and

in response to determining the predetermined period of time has lapsed, deactivate one or more of the speech commands that are specific to the given interface mode.

14. The computing device ofclaim 13, wherein the instructions further comprise instructions to:

while the computing device is in the given interface mode and while the one or more speech commands are deactivated:

in response to determining the given speech command, of the one or more speech commands, is included in the audio data without the predefined guard phrase, and in response to determining that the audio data is not received within the predetermined period of time:

refrain from performing one or more of the actions, via the computing device, that correspond to the given speech command.

15. The computing device ofclaim 14, wherein the instructions further comprise instructions to:

subsequent to refraining from performing one or more of the actions, via the computing device, that correspond to the given speech command:

receive additional audio data captured by the at least one audio sensor of the computing device, the additional audio data including at least the predefined guard phrase; and

re-activate one or more speech of the commands that are specific to the given interface mode.

16. The computing device ofclaim 12, wherein the instructions further comprise instructions to:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

display a visual cue for one or more of the speech commands via a display of the computing device.

17. The computing device ofclaim 16, wherein the instructions further comprise instructions to:

while the computing device is in the given interface mode and while the one or more speech commands are activated:

determine the predetermined period of time has lapsed; and

in response to determining the predetermined period of time has lapsed, cause the visual cue for the one or more speech commands to be removed from the display of the computing device.

18. The computing device ofclaim 12,

wherein the instructions to activate the one or more speech commands that are specific to the given interface mode comprise instructions to load, at the computing device, at least one hotword process for the one or more speech commands; and

wherein the instructions to analyze, based on the one or more speech commands being activated, the audio data to determine whether any of the one or more speech commands are included in the second audio data comprise instructions to:

analyze the audio data using the at least one hotword process.

19. The computing device ofclaim 12, wherein the sensor data captured by the at least one sensor of the computing device comprises preceding audio data captured by the at least one audio sensor of the computing device, the preceding audio data including at least the predefined guard phrase and an indication of the given interface mode.

20. A non-transitory computer-readable storage medium storing instructions executable by at least one processor, the instructions including instructions to:

transition the computing device into a given interface mode in response to receiving sensor data captured by at least one sensor of the computing device;

in response to the computing device being in the given interface mode:

activate one or more speech commands that are specific to the given interface mode,

wherein the given interface mode corresponds to a current state of a user interface of the computing device, and

wherein the given interface mode is one of multiple interface modes each corresponding to corresponding alternate states of the user interface;

while the computing device is in the given interface mode and while the one or more speech commands are activated:

receive audio data captured by at least one audio sensor of the computing device;

analyze, based on the one or more speech commands being activated, the audio data to determine whether any of the one or more speech commands are included in the audio data;

in response to determining a given speech command, of the one or more speech commands, is included in the audio data without a predefined guard phrase, and in response to determining that the audio data is received within a predetermined period of time of transitioning the computing device into the given interface mode:

perform one or more actions, via the computing device, that correspond to the given speech command.

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