Patent Publication Number: US-2022236795-A1

Title: Systems and methods for signaling the onset of a user&#39;s intent to interact

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/142,415, filed 27 Jan. 2021, the disclosures of each of which are incorporated, in their entirety, by this reference. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the present disclosure. 
       FIG. 1  is a block diagram of an exemplary system for signaling and/or reacting to the onset of a user&#39;s intent to interact with the exemplary system, according to at least one embodiment of the present disclosure. 
       FIG. 2  is a block diagram of an exemplary user-input system for enabling a user to target and select physical and/or virtual objects with which to interact, according to at least one embodiment of the present disclosure. 
       FIG. 3  is a diagram of an exemplary data flow associated with an exemplary intelligent-facilitation subsystem, according to at least one embodiment of the present disclosure. 
       FIG. 4  is a block diagram of an exemplary wearable device that signals and/or reacts to the onset of a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 5  is a flow diagram of an exemplary method for signaling the onset of a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 6  is a diagram of an exemplary data flow for using biosensor data to generate intent-to-interact signals, according to at least one embodiment of the present disclosure. 
       FIG. 7  is a diagram of an exemplary pre-processing data flow for generating gaze events and other gaze features from eye-tracking data, according to at least one embodiment of the present disclosure. 
       FIG. 8  is a flow diagram of an exemplary method for intelligently facilitating user input in response to the onset of a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 9  is a flow diagram of an exemplary method for predicting and reacting to a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 10  is a diagram of an exemplary data flow for predicting and reacting to a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 11  is a diagram of another exemplary data flow for predicting and reacting to a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 12  is a diagram of another exemplary data flow for predicting and reacting to a user&#39;s intent to interact, according to at least one embodiment of the present disclosure. 
       FIG. 13  is an illustration of exemplary augmented-reality glasses that may be used in connection with embodiments of this disclosure. 
       FIG. 14  is an illustration of an exemplary virtual-reality headset that may be used in connection with embodiments of this disclosure. 
       FIG. 15  is an illustration of exemplary haptic devices that may be used in connection with embodiments of this disclosure. 
       FIG. 16  is an illustration of an exemplary virtual-reality environment according to embodiments of this disclosure. 
       FIG. 17  is an illustration of an exemplary augmented-reality environment according to embodiments of this disclosure. 
       FIG. 18  an illustration of an exemplary system that incorporates an eye-tracking subsystem capable of tracking a user&#39;s eye(s). 
       FIG. 19  is a more detailed illustration of various aspects of the eye-tracking subsystem illustrated in  FIG. 18 . 
       FIGS. 20A and 20B  are illustrations of an exemplary human-machine interface configured to be worn around a user&#39;s lower arm or wrist. 
       FIGS. 21A and 21B  are illustrations of an exemplary schematic diagram with internal components of a wearable system. 
       FIG. 22  is a schematic diagram of components of an exemplary biosignal sensing system in accordance with some embodiments of the technology described herein. 
    
    
     Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Augmented Reality (AR) systems, Virtual Reality (VR) systems, and Mixed Reality (MR) systems, collectively referred to as Extended Reality (XR) systems, are a budding segment of today&#39;s personal computing systems. XR systems, especially wearable XR systems such as head-mounted XR systems, may be poised to usher in an entirely new era of personal computing by providing users with persistent “always-on” assistance, which may be integrated seamlessly into the users&#39; day-to-day lives without being disruptive. In contrast to more traditional personal computing devices, such as laptops or smartphones, XR devices may be capable of displaying outputs to users in a more accessible, lower-friction manner. For example, some head-mounted XR devices may include displays that are always in users fields of view with which the XR devices may present visual outputs to the users. In some instances, head-mounted XR devices may tightly couple displayed outputs to the users&#39; physical environments (e.g., by placing labels or menus on real-world objects) such that users may not need to look away from their physical environments to consume the displayed outputs. 
     In contrast to traditional personal computing devices, XR devices often rely on input modalities (e.g., hand gestures or speech) that are cumbersome, ambiguous, lower precision, and/or noisier, which may make accessing the information and/or options provided by traditional XR devices physically and/or cognitively fatiguing and difficult to access and/or navigate. Additionally, in some instances, these input modalities may not always be driven by intentional interactions with the XR devices. For example, a user of an XR device may point for emphasis during conversation but not intend the pointing to indicate a targeting or selection input for the XR device. Similarly, a user may say a word or phrase associated with a voice command of an XR device during conversation without intending to trigger the XR device to perform an action associated with the voice command. 
     Unlike traditional personal computing devices, XR devices often have interaction environments that are unknown, less known, or not prespecified, which may cause some XR systems to consume considerable amounts of computing resources to discover objects within such environments with which users of the XR devices may interact. If users have no immediate intentions to interact with the objects in their environments, any resources consumed in discovering the objects and/or user interactions may be wasted. Additionally, if an XR device is capable of presenting information about and/or options for interacting with objects in the users&#39; environment, users may be distracted or annoyed by the information and/or options whenever the users have no immediate intentions to interact with the objects in their environments. 
     The present disclosure is generally directed to systems and methods for using biosignals (e.g., eye-tracking data or other biosignals indicative of gaze dynamics, such as pupil dynamics) to anticipate and signal, in real time, the temporal onset of a user&#39;s intent to interact with the disclosed systems. In some embodiments, the disclosed systems may anticipate when a user intends to interact (e.g., a user&#39;s intention to perform a selection or a user&#39;s intention to provide user input) and/or may intelligently facilitate the user&#39;s interaction or input in a way that reduces the physical and cognitive burden on the user (e.g., via adaptive and/or predictive interfaces). By anticipating the timing of a user&#39;s intent to interact, the systems and methods disclosed herein may responsively drive ultra-low-friction predictive interfaces to avoid overburdening the user with all of the potential actions or user-interface elements available to the user. In some embodiments, the disclosed systems and methods may generate signals indicating the timing of a user&#39;s intent to interact with a computing system that may allow intelligent facilitation systems to provide adaptive interventions at just the right time. 
     Some embodiments of the present disclosure may predict the onset of a user&#39;s intent to interact without first gathering or relying on knowledge of the user&#39;s environment and/or the user&#39;s gaze point in that environment. In some embodiments, the disclosed systems may refrain from gathering knowledge of the user&#39;s environment and/or the user&#39;s gaze point in that environment in order to discover objects within the environment with which the user may interact until after the onset of a user&#39;s intent to interact is detected, which may conserve system resources during periods of time when the user does not intent to interact with the disclosed systems. 
     Features from any of the embodiments described herein may be used in combination with one another in accordance with the general principles described herein. These and other embodiments, features, and advantages will be more fully understood upon reading the following detailed description in conjunction with the accompanying drawings and claims. 
     The following will provide, with reference to  FIGS. 1-4 , detailed descriptions of exemplary systems and subsystems for anticipating, signaling, and/or adapting to a user&#39;s intent to interact with computing systems, such as XR systems. The discussions corresponding to  FIGS. 5-12  will provide detailed descriptions of corresponding methods and data flows. Finally, with reference to  FIGS. 13-22 , the following will provide detailed descriptions of various extended-reality systems and components that may implement embodiments of the present disclosure. 
       FIG. 1  is a block diagram of an example system  100  for signaling the onset of a user&#39;s intent to interact. As illustrated in this figure, example system  100  may include one or more modules  102  for performing one or more tasks. As will be explained in greater detail below, modules  102  may include an acquiring module  104  that acquires biosignals (e.g., eye-tracking signals indicative of gaze dynamics) generated by users of example system  100 . Example system  100  may also include a predicting module  106  that uses the biosignals acquired by acquiring module  104  to anticipate the onset of the users&#39; intentions to interact with example system  100 . Example system  100  may further include a signaling module  108  that provides, to one or more intelligent-facilitation subsystems, intent-to-interact signals indicating the onset of the users&#39; intentions to interact with example system  100 . 
     In some embodiments, example system  100  may enable a user to interact with various types and forms of objects. For example, example system  100  may include one or more user interfaces (e.g., user interface(s)  111 ) with which a user may interact with objects associated with example system  100 . In some examples, example system  100  may enable a user to use example system  100  to interact with physical objects (e.g., a television, a light, a smart device, an Internet-Of-Things (IOT) device, etc.) in the user&#39;s environment. In some examples, example system  100  may present virtual objects to a user with which the user may use example system  100  to interact. In some examples, example system  100  may present a menu of options or commands (e.g., as part of a graphical user interface) that the user may interact with in order to control example system  100  and/or other physical or virtual objects that are made interactable by, presented by, or otherwise associated with example system  100 . In some embodiments, a physical object may be considered to be associated with example system  100  if example system  100  enables a user to interact with the physical object. In some embodiments, a virtual object may be considered to be associated with example system  100  if example system  100  presents (e.g., visually presents) the object to the user. 
     As illustrated in  FIG. 1 , example system  100  may include one or more targeting subsystems (e.g., targeting subsystem(s)  101 ) that may enable users of example system  100  to explicitly target for interaction (e.g., by pointing at, moving a cursor to, scrolling to, highlighting, activating, summoning, instantiating, or otherwise indicating a selection of) one or more objects associated with example system  100 . In some embodiments, targeting subsystem(s)  101  may represent or include a device or system, or a collection of devices or systems, with which a user may target, point to, or otherwise identify an object before and/or as part of interacting with the object. Examples of targeting subsystem(s)  101  include, without limitation, computer mice, trackballs, styluses, keyboards, keypads, joysticks, touchpads, touchscreens, dials, wheels, finger-tracking systems (e.g., a finger-tracking system that tracks a user&#39;s fingers and/or that enables the user to target objects by pointing at the objects), hand-tracking systems (e.g., a hand-tracking system that enables a user to target an object for interaction by pointing at or touching the object with their hands or virtual hands controlled by the hand-tracking system), body-tracking systems, eye-tracking systems (e.g., an eye-tracking system that enables a user to target an object by looking at the object with their eyes or virtual eyes controlled by the eye-tracking system), gesture-recognition systems (e.g., a gesture-recognition system that enables a user to perform a gesture to target an object), speech-recognition systems (e.g., a speech-recognition system that enables a user to target objects using voice commands), pointing devices, motion-tracking devices, position-tracking devices, variations or combinations of one or more of the same, or any other type or form of targeting device or system. 
     As illustrated in  FIG. 1 , example system  100  may include one or more interaction subsystems (e.g., interaction subsystem(s)  103 ) that may enable users of example system  100  to initiate an interaction with (e.g., by clicking on or otherwise initiating a selection of) one or more objects. In some embodiments, interaction subsystem(s)  103  may represent or include a device or system, or a collection of devices or systems, with which a user may initiate an interaction with an object before and/or as part of interacting with the object. Examples of interaction subsystem(s)  103  include, without limitation, clickable or touch sensitive buttons of computer mice, joysticks, or trackballs, tap-detection systems of styluses, touchpads, or touchscreens, enter or return keys of keyboards or keypads, clickable or touch sensitive buttons associated with dial or wheel selectors, finger-tracking systems (e.g., a finger-tracking system that enables a user to initiate an interaction with objects by touching or tapping on an object), hand-tracking systems (e.g., a hand-tracking system that enables a user to initiate an interaction with an object by touching the object with their hands or virtual hands controlled by the hand-tracking system), body-tracking systems, eye-tracking systems (e.g., an eye-tracking system that enables a user to initiate an interaction with an object by looking at the object for a predetermined amount of time), gesture-recognition systems (e.g., a gesture-recognition system that enables a user to perform a gesture, such as a pinch gesture, to initiate an interaction with an object), speech-recognition systems (e.g., a speech-recognition system that enables a user to initiate an interaction with objects using voice commands), pointing devices, motion-tracking devices, position-tracking devices, variations or combinations of one or more of the same, or any other type or form of interaction device or system. 
     In some embodiments, one or more of targeting subsystem(s)  101  and/or one or more of interaction subsystem(s)  103  may represent or collectively form all or a portion of a user-input subsystem, such as a point-and-click or a point-and-select user-input system, of example system  100 .  FIG. 2  is a block diagram of an example user-input system  200  having a user-input module  202  for enabling a user to target and select one or more objects (e.g., objects  201 - 207 ) via user interface  111 . In this example, targeting subsystem  101  may enable the user to explicitly target object  205  prior to selection via interaction subsystem(s)  103 . In this example, user-input module  202  may generate, in response to input from both targeting subsystem  101  and interaction subsystem  103 , a target selection  204  identifying object  205  as having been selected by the user. 
     Returning to  FIG. 1 , example system  100  may further include one or more intelligent-facilitation subsystems (e.g., intelligent-facilitation subsystem(s)  105 ) that may facilitate user interactions involving example system  100  and/or user input to example system  100  by targeting objects on behalf of a user. Intelligent-facilitation subsystem  105  may target objects on behalf of a user in a variety of ways (for example, via adaptive and/or predictive interfaces). In some examples, intelligent-facilitation subsystem  105  may target objects on behalf of a user by performing one or more of the functions provided by targeting subsystem(s)  101  and/or interaction subsystem(s)  103 . In some embodiments, intelligent-facilitation subsystem(s)  105  may suggest potential targets to users and/or enable users to select or interact with suggested targets through a low-friction input (e.g., a button press or click). 
       FIG. 3  illustrates an exemplary data flow  300  for intelligently facilitating a user interaction with example system  100 . In this example, signaling module  108  may provide, to intelligent-facilitation subsystem  105 , an intent-to-interact signal  302  indicating the onset of a user&#39;s intention to interact with example system  100 . In some embodiments, intelligent-facilitation subsystem  105  may react to intent-to-interact signal  302  by adapting user interface(s)  111  to intelligently facilitate a user interaction with example system  100 . In one example, intelligent-facilitation subsystem  105  may first predict the user interaction and may then provide a quicklink or shortcut via user interface(s)  111  that enables the user to complete the predicted interaction with less friction than manual targeting and selection. For example, intelligent-facilitation subsystem  105  may identify an object that the user will most likely interact with and may target or highlight the object for the user within user interface(s)  111 . In some examples, intelligent-facilitation subsystem  105  may additionally or alternatively provide a quicklink or shortcut via user interface(s)  111  that enables the user to target an object without manually targeting the object using targeting subsystem(s)  101 . In at least one embodiment, intelligent-facilitation subsystem  105  may map the quicklink or shortcut to an input gesture and may allow the user to complete the action by performing the input gesture. In some embodiments, intelligent-facilitation subsystem  105  may react to intent-to-interact signal  302  by providing a facilitated targeting input  304  to targeting subsystem  101  on behalf of the user. 
     Returning to  FIG. 1 , example system  100  may include one or more sensors (e.g., biosensor(s)  107  and/or environmental sensor(s)  109 ) for acquiring information about users of example system  100  and/or their environments. In some embodiments, biosensor(s)  107  may represent or include one or more physiological sensors capable of generating real-time biosignals indicative of one or more physiological characteristics of users and/or for making real-time measurements of biopotential signals generated by users. A physiological sensor may represent or include any sensor that detects or measures a physiological characteristic or aspect of a user (e.g., gaze, pupil diameter, pupil area, pupil ellipsoid axis (major and/or minor) lengths, iris radius, heart rate, respiration, perspiration, skin temperature, body position, and so on). In some embodiments, biosensor(s)  107  may collect, receive, and/or identify biosensor data that indicates, either directly or indirectly, physiological information that may be associated with and/or help identify users&#39; intentions to interact with example system  100 . In some examples, biosensor(s)  107  may represent or include one or more human-facing sensors capable of measuring physiological characteristics of users. Examples of biosensor(s)  107  include, without limitation, eye-tracking sensors, hand-tracking sensors, body-tracking sensors, heart-rate sensors, cardiac sensors, neuromuscular sensors, electrooculography (EOG) sensors, electromyography (EMG) sensors, electroencephalography (EEG) sensors, electrocardiography (ECG) sensors, microphones, visible light cameras, infrared cameras, ambient light sensors (ALSs), inertial measurement units (IMUS), heat flux sensors, temperature sensors configured to measure skin temperature, humidity sensors, bio-chemical sensors, touch sensors, proximity sensors, biometric sensors, saturated-oxygen sensors, biopotential sensors, bioimpedance sensors, pedometer sensors, optical sensors, sweat sensors, variations or combinations of one or more of the same, or any other type or form of biosignal-sensing device or system. 
     In some embodiments, environmental sensor(s)  109  may represent or include one or more sensing devices capable of generating real-time signals indicative of one or more characteristics of users&#39; environments. In some embodiments, environmental sensor(s)  109  may collect, receive, and/or identify data that indicates, either directly or indirectly, objects within a user&#39;s environment with which a user may interact. Examples of environmental sensor(s)  109  include, without limitation, cameras, microphones, Simultaneous Localization and Mapping (SLAM) sensors, Radio-Frequency Identification (RFID) sensors, variations or combinations of one or more of the same, or any other type or form of environment-sensing or object-sensing device or system. 
     As further illustrated in  FIG. 1 , example system  100  may also include one or more intent-predicting models, such as intent-predicting model(s)  140 , trained and/or otherwise configured to predict the onset of a user&#39;s intent to interact with example system  100  and/or otherwise model user interaction intent. In at least one embodiment, intent-predicting model(s)  140  may include or represent a gazed-based predictive model that takes as input information indicative of gaze dynamics and/or eye movements and outputs a prediction (e.g., a probability or binary indicator) of the onset of a user&#39;s intent to interact with example system  100 . In some embodiments, the disclosed systems may train intent-predicting model  140  to make real-time predictions of user interactions, decode moments of interaction from gaze data, and/or predict the temporal onset of user interactions. In some embodiments, the disclosed systems may train intent-predicting model  140  to predict the temporal onset of interaction intent using nothing more than gaze dynamics leading up to the moment of user interaction. In at least one example, the disclosed systems may train intent-predicting model  140  to predict the temporal onset of interaction intent using only eye-tracking data that preceded interaction (e.g., selection) events. 
     Intent-predicting model(s)  140  may represent or include any machine-learning model, algorithm, heuristic, data, or combination thereof, that may anticipate, recognize, detect, estimate, predict, label, infer, and/or react to the temporal onset of a user&#39;s intent to interact with example system  100  based on and/or using biosignals acquired from one or more biosensors, such as biosensors  107 . Examples of intent-predicting model(s)  140  include, without limitation, decision trees (e.g., boosting decision trees), neural networks (e.g., a deep convolutional neural network), deep-learning models, support vector machines, linear classifiers, non-linear classifiers, perceptrons, naive Bayes classifiers, any other machine-learning or classification techniques or algorithms, or any combination thereof. 
     The systems describe herein may train intent-to-interact models, such as intent-predicting model  140 , to predict the timing of user interactions in any suitable way. In one example, the systems may train an intent-to-interact model to predict when a user is starting to and/or about to perform an interaction using a ground-truth time series of physiological data that includes physiological data recorded before and/or up to the interaction. In some examples, the time series may include samples preceding a user&#39;s interactions by approximately 10 ms, 50 ms, 100 ms, 200 ms, 300 ms, 400 ms, 500 ms, 600 ms, 700 ms, 800 ms, 900 ms, 1000 ms, 1100 ms, 1200 ms, 1300 ms, 1400 ms, 1500 ms, 1600 ms, 1700 ms, 1800 ms, 1900 ms, or 2000 ms. Additionally or alternatively, the time series include samples preceding a user&#39;s interactions by approximately 2100 ms, 2200 ms, 2300 ms, 2400 ms, 2500 ms, 2600 ms, 2700 ms, 2800 ms, 2900 ms, 3000 ms, 3100 ms, 3200 ms, 3300 ms, 3400 ms, 3500 ms, 3600 ms, 3700 ms, 3800 ms, 3900 ms, 4000 ms, 4100 ms, 4200 ms, 4300 ms, 4400 ms, 4500 ms, 4600 ms, 4700 ms, 4800 ms, 4900 ms, 5000 ms, 5100 ms, 5200 ms, 5300 ms, 5400 ms, 5500 ms, 5600 ms, 5700 ms, 5800 ms, 5900 ms, 6000 ms, 6100 ms, 6200 ms, 6300 ms, 6400 ms, 6500 ms, 6600 ms, 6700 ms, 6800 ms, 6900 ms, 7000 ms, 7100 ms, 7200 ms, 7300 ms, 7400 ms, 7500 ms, 7600 ms, 7700 ms, 7800 ms, 7900 ms, 8000 ms, 8100 ms, 8200 ms, 8300 ms, 8400 ms, 8500 ms, 8600 ms, 8700 ms, 8800 ms, 8900 ms, 9000 ms, 9100 ms, 9200 ms, 9300 ms, 9400 ms, 9500 ms, 9600 ms, 9700 ms, 9800 ms, 9900 ms, 10000 ms, 10100 ms, 10200 ms, 10300 ms, 10400 ms, 10500 ms, 10600 ms, 10700 ms, 10800 ms, or 10900 ms. In some embodiments, an intent-to-interact model may take as input a similar time series of physiological data. 
     In some embodiments, the disclosed systems may use one or more intent-predicting models (e.g., an intent-predicting model trained for an individual user or an intent-predicting model trained for a group of users). In at least one embodiment, the disclosed systems may train intent-to-interact models to make predictions for interaction intents that are on the scale of milliseconds or seconds. 
     As further illustrated in  FIG. 1 , example system  100  may also include one or more memory devices, such as memory  120 . Memory  120  may include or represent any type or form of volatile or non-volatile storage device or medium capable of storing data and/or computer-readable instructions. In one example, memory  120  may store, load, and/or maintain one or more of modules  102 . Examples of memory  120  include, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory. 
     As further illustrated in  FIG. 1 , example system  100  may also include one or more physical processors, such as physical processor  130 . Physical processor  130  may include or represent any type or form of hardware-implemented processing unit capable of interpreting and/or executing computer-readable instructions. In one example, physical processor  130  may access and/or modify one or more of modules  102  stored in memory  120 . Additionally or alternatively, physical processor  130  may execute one or more of modules  102  to facilitate prediction or signaling of user intentions to interact with example system  100 . Examples of physical processor  130  include, without limitation, microprocessors, microcontrollers, central processing units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor. 
     System  100  in  FIG. 1  may be implemented in a variety of ways. For example, all or a portion of system  100  may represent portions of an example system  400  in  FIG. 4 . As shown in  FIG. 4 , system  400  may include a wearable device  402  (e.g., a wearable XR device) having (1) one or more user-facing sensors (e.g. biosensor(s)  107 ) capable of acquiring biosignal data generated by a user  404 , (2) one or more environment-facing sensors (e.g., environmental sensor(s)  109 ) capable of acquiring environmental data about a real-world environment  406  of user  404 , and/or (3) a display  408  capable of displaying objects to user  404 . 
     As shown in  FIG. 4 , wearable device  402  may be programmed with one or more of modules  102  from  FIG. 1  (e.g., acquiring module  104 , predicting module  106 , and/or signaling module  108 ) that may, when executed by wearable device  402 , enable wearable device  402  to (1) acquire, via one or more of biosensor(s)  107 , one or more biosignals generated by user 0   404 , (2) use the one or more biosignals to anticipate the onset of an intent of user  404  to interact with wearable device  402 , and (3) provide an intent-to-interact signal indicating the onset of the intent of user  404  to interact to an intelligent-facilitation subsystem of wearable device  402 . While not illustrated in  FIG. 4 , in some embodiments, example system  400  and/or wearable device  402  may also include (1) at least one targeting subsystem that may enable user  404  to explicitly target, for interaction, one or more of objects  401  and  403 , (2) at least one interaction subsystem that may enable user  404  to interact with, when targeted, one or more of objects  401  and  403 , and (3) an intelligent-facilitation subsystem that may target one or more of the objects on behalf of the user in response to intent-to-interact signals received from signaling module  108 . 
       FIG. 5  is a flow diagram of an exemplary computer-implemented method  500  for signaling a user&#39;s intent to interact with a computing system, such as an XR system. The steps shown in  FIG. 5  may be performed by any suitable computer-executable code and/or computing system, including the system(s) illustrated in  FIGS. 1-4 and 13-22 . In one example, each of the steps shown in  FIG. 5  may represent an algorithm whose structure includes and/or is represented by multiple sub-steps, examples of which will be provided in greater detail below. 
     As illustrated in  FIG. 5 , at step  510  one or more of the systems described herein may acquire, via one or more biosensors, one or more biosignals generated by a user of a computing system. For example, acquiring module  104  may, as part of wearable device  402  in  FIG. 4 , use one or more of biosensors  107  to acquire one or more raw and/or derived biosignals generated by user  404 . 
     The systems described herein may perform step  510  in a variety of ways.  FIG. 6  illustrates an exemplary data flow  600  for acquiring biosignal data and using the biosignal data to generate intent-to-interact signals. As shown in this figure, in some embodiments, the disclosed systems may receive raw biosignal(s)  602  from biosensor(s)  107  and may use raw biosignal(s)  602  as input to intent-predicting model  140 . Additionally or alternatively, the disclosed systems may generate one or more derived biosignal(s)  606  by performing one or more pre-processing operation(s)  604  (e.g., event-detection or feature-extraction operations) on raw biosignal(s)  602  and then may use derived biosignal(s)  606  as input to intent-predicting model  140 . 
       FIG. 7  illustrates an exemplary real-time pre-processing pipeline  700  that may be used by the disclosed systems to transform raw, real-time eye-tracking data into one or more of the features disclosed herein from which a user&#39;s interaction intent may be anticipated. In this example, the disclosed systems may acquire a stream of real-time, 3D gaze vectors  702  from an eye-tracking system. In some examples, 3D gaze vectors  702  may be in an eye-in-head frame of reference, and the disclosed systems may transform 3D gaze vectors  702  to an eye-in-world frame of reference using a suitable reference-frame transformation  704  (e.g., using information indicating the user&#39;s head orientation), which may result in transformed 3D gaze vectors  706 . Next, the disclosed systems may compute angular displacements  710  between consecutive samples from gaze vectors  706  using a suitable angular-displacement calculation  708 . For example, the disclosed system may compute angular displacements  710  between consecutive samples from gaze vectors  706  using Equation (1): 
       θ=2×atan 2(| u−v|, |u+v |)   (1)
 
     where consecutive samples of gaze vectors  706  are represented as normalized vectors u and v and the corresponding angular displacement is represented as θ. 
     The disclosed systems may then calculate gaze velocities  714  from angular displacements  710  using a suitable gaze-velocity calculation  712 . For example, the disclosed systems may divide each sample from angular displacements  710  (e.g., θ, as calculated above) by the change in time between associated consecutive samples from gaze vectors  706 . 
     In some embodiments, the disclosed systems may perform one or more filtering operation(s)  716  on gaze velocities  712  (e.g., to remove noise and/or unwanted segments before downstream event detection and feature extraction). In at least one embodiment, the disclosed systems may remove all samples where gaze velocity exceeds about 800 degrees/second, which may indicate unfeasibly fast eye movements. The disclosed systems may then replace removed values through interpolation. Additionally or alternatively, the disclosed systems may apply a median filter (e.g., a median filter with a width of seven samples) to gaze velocities  714  to smooth the signal and/or account for noise. 
     In some embodiments, the disclosed systems may generate gaze events  722  from gaze velocities  714  by performing one or more event-detection operation(s)  718 . In some embodiments, the disclosed systems may detect fixation events (e.g., moments of maintaining visual gaze on a single location) and/or saccade events (e.g., moments of rapid eye movement between points of fixation) from gaze velocities  714  using any suitable detection model, algorithm, or heuristic. For example, the disclosed systems may perform saccade detection using a suitable saccade detection algorithm (e.g., Velocity-Threshold Identification (I-VT), Dispersion-Threshold Identification (I-DT), or Hidden Markov Model Identification (I-HMM)). In at least one embodiment, the disclosed systems may perform I-VT saccade detection by identifying consecutive samples from gaze velocities  714  that exceeded about 70 degrees/second. In some embodiments, the disclosed systems may require a minimum duration in the range of about 5 milliseconds to about 30 milliseconds (e.g., 17 milliseconds) and a maximum duration in the range of about 100 milliseconds to about 300 milliseconds (e.g., 200 milliseconds) for saccade events. In some embodiments, the disclosed systems may perform I-DT fixation detection by computing dispersion (e.g., the largest angular displacement from the centroid of gaze samples) over predetermined time windows and marking time windows where dispersion did not exceed about 1 degree as fixation events. In some embodiments, the disclosed systems may require a minimum duration in the range of about 50 milliseconds to about 200 milliseconds (e.g., 100 milliseconds) and a maximum duration in the range of about 0.5 seconds to about 3 seconds (e.g., 2 seconds) for fixation events. 
     In some embodiments, the disclosed systems may generate gaze features  724  by performing one or more event-extraction operation(s)  720  on gaze vectors  702 , gaze vectors  706 , angular displacements  710 , gaze velocities  714 , and/or any other suitable eye-tracking data. The disclosed systems may extract a variety of gaze-based features for use in predicting the onset of a user&#39;s intent to interact with a computing system. Examples of gaze-based features include, without limitation, gaze velocity (e.g., a measure of how fast gaze is moving), ambient attention, focal attention, saccade dynamics, gaze features that characterize visual attention, dispersion (e.g., a measure of how spread out gaze points are over a period of time), event-detection labels, low-level eye movement features derived from gaze events  722 , the K coefficient (e.g., to discern between focal and ambient behavior), pupil dynamics (e.g., dynamics relating to and/or involving pupil diameter, pupil area, pupil ellipsoid axis (major and minor) lengths, and/or iris radius), variations or combinations of one or more of the same, or any other type or form of eye-tracking data. 
     The systems described herein may predict when a user intends to interact using a variety of gaze data and gaze dynamics. For example, the disclosed systems may predict moments of interaction using a combination of gaze velocity, low-level features from fixation and saccade events, and/or mid-level features that recognize patterns in the shape of scan paths. In some embodiments, the systems described herein may predict a user&#39;s intent based on patterns and/or elements of one or more of fixation events (e.g., whether or not a user is fixated on something), gaze velocity, fixation average velocity, saccade acceleration skew in the x direction, saccade standard deviation in the y direction, saccade velocity kurtosis, saccade velocity skew, saccade velocity skew in the y direction, saccade duration, ambient/focal K coefficient, saccade velocity standard deviation, saccade distance from previous saccade, dispersion, fixation duration, fixation kurtosis in the y direction, saccade velocity kurtosis in the x direction, saccade velocity skew in the x direction, saccade amplitude, saccade standard deviation in the x direction, fixation kurtosis in the x direction, saccade acceleration kurtosis in the y direction, saccade acceleration skew, fixation skew in the y direction, saccade acceleration kurtosis in the x direction, saccade events (e.g., whether or not a user is performing a saccade), saccade dispersion, fixation standard deviation in the x direction, fixation skew in the x direction, saccade velocity mean, fixation standard deviation in the y direction, saccade velocity kurtosis in the y direction, fixation angle from previous fixation, saccade angle from previous saccade, saccade velocity median in the x direction, fixation path length, saccade acceleration skew in the y direction, fixation dispersion, saccade acceleration kurtosis, saccade path length, saccade acceleration median in the y direction, saccade velocity mean in the x direction, saccade acceleration median in the y direction, saccade velocity mean in the x direction, saccade acceleration standard deviation in the x direction, saccade velocity mean in the y direction, saccade acceleration mean, saccade acceleration mean in the x direction, saccade acceleration median in the x direction, saccade acceleration standard deviation, saccade acceleration standard deviation in the y direction, saccade velocity standard deviation in the y direction, saccade acceleration maximum in the x direction, saccade velocity median, saccade velocity maximum in the x direction, saccade acceleration maximum, saccade acceleration median, saccade velocity median in the y direction, saccade acceleration mean in the y direction, saccade ratio, saccade velocity standard deviation in the x direction. Additionally or alternatively, the systems described herein may predict a user&#39;s intent based on gaze velocity, any suitable measure of ambient/focal attention, statistical features of saccadic eye movements, blink patterns, scan path patterns, and/or changes to pupil features. 
     Returning to  FIG. 5  at step  520 , one or more of the systems described herein may use the one or more biosignals acquired at step  510  to anticipate an intent of a user to interact with a computing system. For example, predicting module  106  may use, as part of wearable device  402 , one or more of biosignals  602  and/or  606  to anticipate the onset of an intent of user  404  to interact with wearable device  402 . The systems described herein may perform step  520  in a variety of ways. In one example, the disclosed systems may use a suitably trained predictive model (e.g., intent-predicting model  140 ) to predict the onset of user intentions to interact. In some examples, the disclosed systems may train the predictive model to predict when a user intends to use a computing device to interact with objects in the real or digital world, the onset of object selection, and/or when a user intends to interact with an XR system. 
     At step  530  one or more of the systems described herein may provide an intent-to-interact signal indicating the intent of the user to interact to an intelligent-facilitation subsystem in response to the intent of the user to interact. For example, signaling module  108  may, as part of wearable device  402  in  FIG. 4 , provide an intent-to-interact signal indicating the intent of user  404  to interact with wearable device  402  to intelligent-facilitation subsystem  105 . 
       FIG. 8  is a flow diagram of an exemplary computer-implemented method  800  for intelligently facilitating user input in response to the onset of a user&#39;s intent to interact. The steps shown in  FIG. 8  may be performed by any suitable computer-executable code and/or computing system, including the system(s) illustrated in  FIGS. 1-4 and 13-22 . In one example, each of the steps shown in  FIG. 8  may represent an algorithm whose structure includes and/or is represented by multiple sub-steps. 
     As illustrated in  FIG. 8 , at step  810  one or more of the systems described herein may identify, in response to receiving an intent-to-interact signal, an object as being most likely to be interacted with by a user. For example, intelligent-facilitation subsystem  105  may, as part of wearable device  402  in  FIG. 4 , identify, in response to receiving an intent-to-interact signal, one of objects  401  or  403  as being most likely to be interacted with by user  404 . At step  820  one or more of the systems described herein may target the at least one of the objects on behalf of the user. For example, intelligent-facilitation subsystem  105  may, as part of wearable device  402  in  FIG. 4 , target one of objects  401  or  403  on behalf of user  404 . At step  830  one or more of the systems described herein may receive, from the user, a request to interact with the targeted object. For example, intelligent-facilitation subsystem  105  may, as part of wearable device  402  in  FIG. 4 , receive a request to interact with one of objects  401  or  403  that was previously targeted by intelligent-facilitation subsystem(s)  105 . At step  840  one or more of the systems described herein may perform an operation in response to receiving the request to interact with the targeted object. For example, intelligent-facilitation subsystem  105  may, as part of wearable device  402  in  FIG. 4 , perform an operation in response to receiving the request to interact with one of objects  401  or  403 . 
       FIG. 9  is a flow diagram of an exemplary computer-implemented method  900  for predicting and reacting to a user&#39;s intent to interact with a computing system. The steps shown in  FIG. 9  may be performed by any suitable computer-executable code and/or computing system, including the system(s) illustrated in  FIGS. 1-4 and 13-22 . In one example, each of the steps shown in  FIG. 9  may represent an algorithm whose structure includes and/or is represented by multiple sub-steps, examples of which will be provided in greater detail below. 
     As illustrated in  FIG. 9 , at step  910  one or more of the systems described herein may monitor, via one or more sensors, one or more physical attributes of a user. For example, acquiring module  104  may use, as part of wearable device  402  in  FIG. 4 , one or more of biosensors  107  to monitor one or more physical attributes of user  404 . 
     In some embodiments, the disclose systems may use biosensors rather than environmental sensors to monitor physical attributes of a user that are environment agnostic, physical attributes of the user that are unrelated to the user&#39;s environment, and/or physical attributes of the user that are unrelated to an XR environment with which the user interacts. In some examples, the systems disclosed herein may monitor physical attributes of a user via any of physiological sensors  1000 ( 1 )-(N) in  FIG. 10 , physiological sensors  1100 ( 1 )-(N) in  FIG. 11 , and/or physiological sensors  1200 ( 1 )-(N) in  FIG. 12 . 
     As illustrated in  FIG. 9 , at step  920  one or more of the systems described herein may provide, as input, the one or more physical attributes of the user to a model trained to detect when the user intends to interact with an extended-reality environment. For example, predicting module  106  may provide, as part of wearable device  402  in  FIG. 4 , the one or more physical attributes monitored at step  910  to intent-predicting model  140  to detect when user  404  intends to interact with wearable device  402 . 
     As illustrated in  FIG. 9 , at step  930  one or more of the systems described herein may receive, as output from the model, an indication of the user&#39;s intent to interact with the extended-reality environment. For example, signaling module  108  or intelligent-facilitation subsystem(s)  105  may receive, as part of wearable device  402  in  FIG. 4 , an indication of an intent of user  404  to interact with wearable device  402  from intent-predicting model  140 . In some embodiments, the disclosed systems may receive an indication of a user&#39;s intent to interact before the user begins to interact. In other embodiments, the disclosed systems may receive an indication of a user&#39;s intent to interact at the onset of an interaction or as the user first begins to interact. 
     As illustrated in  FIG. 9 , at step  940  one or more of the systems described herein may perform, in response to the indication, an extended-reality operation before the user interacts with the extended-reality environment. For example, signaling module  108  or intelligent-facilitation subsystem  105  may, as part of wearable device  402  in  FIG. 4 , perform a signaling or targeting operation in response to receiving an indication of the intent of user  404  to interact with wearable device  402  from intent-predicting model  140 . 
     In some embodiments, the disclosed systems may notify a user-input model (e.g., fusion algorithm  1030  in  FIG. 10 ) of a user&#39;s intent to interact with an extended-reality environment before the user interacts with the extended-reality environment. As shown in  FIG. 10 , fusion algorithm  1030  may receive user-input events or notifications from input sensing model  1010  and intent-to-interact events from intent-to-interact model  1020 . In some embodiments, fusion algorithm  1030  may output a probability selection  1040  based on the user-input events and the intent-to-interact events. In at least one embodiment, probability selection  1040  may include and/or represent a probability that a user-input event was intended. For example, probability selection  1040  may include a lower probability that a user-input event received from input sensing model  1010  was intended if intent-to-interact model  1020  did not output a contemporaneous intent-to-interact event or notification. Similarly, probability selection  1040  may include a higher probability that a user-input event received from input sensing model  1010  was intended if intent-to-interact model  1020  did output a contemporaneous intent-to-interact event or notification. 
     In some embodiments, the disclosed systems may, in response to an indication of a user&#39;s intent to interact with an extended-reality environment, display an interface element of a predictive interface to the user before the user interacts with the extended-reality environment. As shown in  FIG. 11 , interface-adaption module  1130  may receive intent-to-interact events from intent-to-interact model  1120 . In some embodiments, interface-adaption module  1130  may display a user-interface element to the user in response to receiving the intent-to-interact. In some embodiments, interface-adaption module  1130  may determine a suitable user-interface element based on a type of interaction the user is intending to perform, based on physiological sensor data (e.g., gaze data), and/or data received from user input devices. In some embodiments, the user-interface element may be associated with an object visible within the extended-reality environment. For example, the disclosed systems may, in response to an indication of a user&#39;s intent to interact with an object within an extended-reality environment, highlight the object or activate the object (e.g., when the object is a user-interface element) without requiring the user to select or point to the object. The disclosed systems may identify an object that is most likely to be interacted with by identifying the nearest object to the user&#39;s gaze point or pointer position. Alternatively, the user-interface element may not be associated with any object visible within the extended-reality environment. In at least one embodiment, the user may provide user input  1140  via the displayed user-interface element. 
     In some embodiments, the disclosed system may optimize an XR environment in response to an indication of a user&#39;s intent to interact with the XR environment. As shown in  FIG. 12 , XR-environment optimizing module  1230  may receive intent-to-interact events from intent-to-interact model  1220 . In some embodiments, XR-environment optimizing module  1230  may, in response to an indication of a user&#39;s intent to interact with an XR environment, prepare the XR environment for the user to perform an interaction with the XR environment by performing any operations necessary for the user to start performing the interaction. For example, XR-environment optimizing module  1230  may, in response to an indication of a user&#39;s intent to interact with an XR environment, load, into memory, at least one asset most likely to be interacted with by the user before the user interacts with the at least one asset. 
     As described above, the disclosed systems may use gaze data collected from an eye tracker as a rich source of clues for both what a user intends to interact with and when. In some embodiments, the disclosed systems may monitor natural gaze behavior in a transparent and unobtrusive manner. In some embodiments, the disclosed systems may use models that predict a user&#39;s intent to interact from eye movements to drive predictive XR interfaces that provide users with easy-to-use, minimally fatiguing XR interactions for all-day use. 
     Example Embodiments 
     Example 1: A computer-implemented method may include (1) acquiring, via one or more biosensors, one or more biosignals generated by a user of a computing system, (2) using the one or more biosignals to anticipate an intent of the user to interact with the computing system, and (3) providing an intent-to-interact signal indicating the intent of the user to interact to an intelligent-facilitation subsystem. In some examples, the computing system may include (1) at least one targeting subsystem that enables the user to explicitly target, for interaction, one or more objects, (2) at least one interaction subsystem that enables the user to interact with, when targeted, one or more of the objects, and (3) an intelligent-facilitation subsystem that targets one or more of the objects on behalf of the user in response to intent-to-interact signals. 
     Example 2: The computer-implemented method of Example 1 further including (1) identifying, by the intelligent-facilitation subsystem, at least one of the objects as being most likely to be interacted with by the user in response to receiving the intent-to-interact signal indicating the intent of the user to interact, (2) targeting, by the intelligent-facilitation subsystem, the at least one of the objects on behalf of the user, (3) receiving, from the user via the interaction subsystem, a request to interact with the at least one of the objects targeted by the intelligent-facilitation subsystem on behalf of the user, and (4) performing an operation in response to receiving the request to interact with the at least one of the objects. 
     Example 3: The computer-implemented method of any of Examples 1-2, wherein the intelligent-facilitation subsystem refrains from identifying the at least one of the objects until after receiving the intent-to-interact signal. 
     Example 4: The computer-implemented method of any of Examples 1-3 where (1) the one or more biosensors include one or more eye-tracking sensors, (2) the one or more biosignals include signals indicative of gaze dynamics of the user, and (3) the signals indicative of gaze dynamics of the user are used to anticipate the intent of the user to interact. 
     Example 5: The computer-implemented method of any of Examples 1-4 where the signals indicative of gaze dynamics of the user include a measure of gaze velocity. 
     Example 6: The computer-implemented method of any of Examples 1-5 where the signals indicative of gaze dynamics of the user include at least one of (1) a measure of ambient attention and/or (2) a measure of focal attention. 
     Example 7: The computer-implemented method of any of Examples 1-6 wherein the signals indicative of gaze dynamics of the user include a measure of saccade dynamics. 
     Example 8: The computer-implemented method of any of Examples 1-7 where (1) the one or more biosensors include one or more hand-tracking sensors, (2) the one or more biosignals include signals indicative of hand dynamics of the user, and (3) the signals indicative of hand dynamics of the user are used to anticipate the intent of the user to interact. 
     Example 9: The computer-implemented method of any of Examples 1-8 where (1) the one or more biosensors include one or more neuromuscular sensors, (2) the one or more biosignals include neuromuscular signals obtained from the user&#39;s body, and (3) the neuromuscular signals obtained from the user&#39;s body are used to anticipate the intent of the user to interact. 
     Example 10: The computer-implemented method of any of Examples 1-9 where the objects associated with the computing system include one or more physical objects from a real-world environment of the user. 
     Example 11: The computer-implemented method of any of Examples 1-10 where (1) the computing system is an extended-reality system, (2) the computer-implemented method further includes displaying, by the extended-reality system, virtual objects to the user, and (3) the objects associated with the computing system include the virtual objects. 
     Example 12: The computer-implemented method of any of Examples 1-11 where (2) the computing system includes an extended-reality system, (2) the computer-implemented method further includes displaying, by the extended-reality system, a menu to the user, and (3) the objects associated with the computing system include visual elements of the menu. 
     Example 13: The computer-implemented method of any of Examples 1-12 further including training a predictive model to output the intent-to-interact signals. 
     Example 14: A system may include (1) at least one targeting subsystem adapted to enable a user to explicitly target one or more objects for interaction, (2) at least one interaction subsystem adapted to enable the user to interact with, when targeted, one or more of the objects, (3) an intelligent-facilitation subsystem adapted to target the objects on behalf of the user in response to intent-to-interact signals, (3) one or more biosensors adapted to detect biosignals generated by the user, (4) at least one physical processor, and (5) physical memory including computer-executable instructions that, when executed by the physical processor, cause the physical processor to (a) acquire, via the one or more biosensors, the one or more biosignals generated by the user,(b) use the one or more biosignals to anticipate an intent of the user to interact with the system, and (c) provide an intent-to-interact signal indicating the intent of the user to interact with the system to the intelligent-facilitation subsystem in response to the intent of the user to interact with the system. 
     Example 15: The system of Example 14, where (1) the one or more biosensors include one or more eye-tracking sensors adapted to measure gaze dynamics of the user, (2) the one or more biosignals include signals indicative of the gaze dynamics of the user, and (3) the gaze dynamics of the user are used to anticipate the intent of the user to interact with the system. 
     Example 16: The system of any of Examples 14-15, where (1) the one or more biosensors include one or more hand-tracking sensors, (2) the one or more biosignals include signals indicative of hand dynamics of the user, and (3) the signals indicative of hand dynamics of the user are used to anticipate the intent of the user to interact with the computing system. 
     Example 17: The system of any of Examples 14-16, where (1) the one or more biosensors include one or more neuromuscular sensors, (2) the one or more biosignals include neuromuscular signals obtained from the user&#39;s body, and (3) the neuromuscular signals obtained from the user&#39;s body are used to anticipate the intent of the user to interact with the computing system. 
     Example 18: The system of any of Examples 14-17, where (1) the at least one targeting subsystem includes a pointing subsystem of a physical controller and (2) the at least one interaction subsystem includes a selecting subsystem of the physical controller. 
     Example 19: The system of any of Examples 14-18, where (1) the intelligent-facilitation subsystem is further adapted to (a) identify at least one of the objects as being most likely to be interacted with by the user in response to receiving the intent-to-interact signal indicating the intent of the user to interact with the computing system and (b) target the at least one of the objects on behalf of the user and (2) the physical memory further includes additional computer-executable instructions that, when executed by the physical processor, cause the physical processor to (a) receive, from the user via the interaction subsystem, a request to interact with the at least one of the objects targeted by the intelligent-facilitation subsystem and (b) perform an operation in response to receiving the request to interact with the at least one of the objects. 
     Example 20: A non-transitory computer-readable medium may include one or more computer-executable instructions that, when executed by at least one processor of a computing device, cause the computing device to (1) acquire, via one or more biosensors, one or more biosignals generated by a user of the computing device, (2) use the one or more biosignals to anticipate an intent of the user to interact with the objects using the computing device, and (3) provide an intent-to-interact signal indicating an intent of the user to interact with the computing device to the intelligent-facilitation subsystem in response to the intent of the user to interact with the computing device. In some examples, the computing device may include (1) at least one targeting subsystem that enables the user to explicitly target, for interaction, one or more of the objects, (2) at least one interaction subsystem that enables the user to interact with, when targeted, one or more of the objects, and (3) an intelligent-facilitation subsystem that targets one or more of the objects on behalf of the user in response to intent-to-interact signals. 
     Example 21: A computer-implemented method for predicting an intent to interact may include (1) monitoring, via one or more sensors, one or more physical attributes of a user, (2) providing, as input, the one or more physical attributes of the user to a model trained to detect when the user intends to interact with an extended-reality environment, (3) receiving, as output from the model, an indication of the user&#39;s intent to interact with the extended-reality environment, and (4) performing, in response to the indication, an extended-reality operation before the user interacts with the extended-reality environment. 
     Example 22: The computer-implemented method of any of Examples 1-13 or 21, wherein (1) the one or more sensors comprise one or more eye-tracking sensors and (2) monitoring the one or more physical attributes of the user may include monitoring one or more gaze attributes of the user. 
     Example 23: The computer-implemented method of any of Examples 1-13, 21, and/or 22, wherein the one or more gaze attributes of the user include one or more of a fixation attribute, a gaze velocity attribute, a gaze acceleration attribute, and/or a saccade attribute. 
     Example 24: The computer-implemented method of any of Examples 1-13 and/or 21-23, wherein monitoring the one or more physical attributes of the user may include monitoring one or more neuromuscular attributes of the user. 
     Example 25: The computer-implemented method of any of Examples 1-13 and/or 21-24, wherein performing the extended-reality operation may include notifying an interaction model of the user&#39;s intent to interact with the extended-reality environment before the user interacts with the extended-reality environment. 
     Example 26: The computer-implemented method of any of Examples 1-13 and/or 1-5, wherein performing the extended-reality operation may include displaying an interface element to the user before the user interacts with the extended-reality environment. 
     Example 27: The computer-implemented method of any of Examples 1-13 and/or 21-26, wherein performing the extended-reality operation may include displaying an interface element for interacting with an object in the extended-reality environment to the user before the user interacts with the object in the extended-reality environment. 
     Example 28: The computer-implemented method of any of Examples 1-13 and/or 21-27, wherein performing the extended-reality operation may include (1) identifying, in response to the indication, an object in the extended-reality environment with which the user is most likely to interact and (2) displaying an interface element for interacting with the object in the extended-reality environment. 
     Example 29: The computer-implemented method of any of Examples 1-13 and/or 21-28, wherein performing the extended-reality operation may include loading, into memory, at least one asset most likely to be interacted with by the user before the user interacts with the at least one asset. 
     Example 30: The computer-implemented method of any of Examples 1-13 and/or 21-29, wherein (1) the indication of the user&#39;s intent may include a prediction that the user will perform a pinch gesture to interact with the extended-reality environment and (2) the extended-reality operation is performed before the user completes the pinch gesture. 
     Example 31: A system may include (1) at least one physical processor and (2) physical memory comprising computer-executable instructions that, when executed by the physical processor, cause the physical processor to (a) monitor, via one or more sensors, one or more physical attributes of a user, (b) provide, as input, the one or more physical attributes of the user to a model trained to detect when the user intends to interact with an extended-reality environment, (c) receive, as output from the model, an indication of the user&#39;s intent to interact with the extended-reality environment, and (d) perform, in response to the indication, an extended-reality operation before the user interacts with the extended-reality environment. 
     Example 32: The system of any of Examples 14-19 and/or 31, wherein (1) the one or more sensors comprise one or more eye-tracking sensors and (2) monitoring the one or more physical attributes of the user may include monitoring one or more gaze attributes of the user. 
     Example 33: The system of any of Examples 14-19, 31, and/or 32, wherein the one or more gaze attributes of the user may include one or more of a fixation attribute, a gaze velocity attribute, a gaze acceleration attribute, or a saccade attribute. 
     Example 34: The system of any of Examples 14-19 and/or 31-33, wherein monitoring the one or more physical attributes of the user may include monitoring one or more neuromuscular attributes of the user. 
     Example 35: The system of any of Examples 14-19 and/or 31-34, wherein performing the extended-reality operation may include notifying an interaction model of the user&#39;s intent to interact with the extended-reality environment before the user interacts with the extended-reality environment. 
     Example 36: The system of any of Examples 14-19 and/or 31-35, wherein performing the extended-reality operation may include displaying an interface element to the user before the user interacts with the extended-reality environment. 
     Example 37: The system of any of Examples 14-19 and/or 31-36, wherein performing the extended-reality operation may include displaying an interface element for interacting with an object in the extended-reality environment to the user before the user interacts with the object in the extended-reality environment. 
     Example 38: The system of any of Examples 31-37, wherein performing the extended-reality operation may include (1) identifying, in response to the indication, an object in the extended-reality environment with which the user is most likely to interact and (2) displaying an interface element for interacting with the object in the extended-reality environment. 
     Example 39: The system of any of Examples 14-19 and/or 31-38, wherein performing the extended-reality operation may include loading, into memory, at least one asset most likely to be interacted with by the user before the user interacts with the at least one asset. 
     Example 40: The system of any of Examples 14-19 and/or 31-39, wherein (1) the indication of the user&#39;s intent may include a prediction that the user will perform a pinch gesture to interact with the extended-reality environment and (2) the extended-reality operation is performed before the user completes the pinch gesture. 
     Example 41: A non-transitory computer-readable medium may include one or more computer-executable instructions that, when executed by at least one processor of a computing device, cause the computing device to (1) monitor, via one or more sensors, one or more physical attributes of a user, (2) provide, as input, the one or more physical attributes of the user to a model trained to detect when the user intends to interact with an extended-reality environment, (3) receive, as output from the model, an indication of the user&#39;s intent to interact with the extended-reality environment, and (4) perform, in response to the indication, an extended-reality operation before the user interacts with the extended-reality environment. 
     Embodiments of the present disclosure may include or be implemented in conjunction with various types of artificial-reality systems. Artificial reality is a form of reality that has been adjusted in some manner before presentation to a user, which may include, for example, a virtual reality, an augmented reality, a mixed reality, a hybrid reality, or some combination and/or derivative thereof. Artificial-reality content may include completely computer-generated content or computer-generated content combined with captured (e.g., real-world) content. The artificial-reality content may include video, audio, haptic feedback, or some combination thereof, any of which may be presented in a single channel or in multiple channels (such as stereo video that produces a three-dimensional (3D) effect to the viewer). Additionally, in some embodiments, artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, that are used to, for example, create content in an artificial reality and/or are otherwise used in (e.g., to perform activities in) an artificial reality. 
     Artificial-reality systems may be implemented in a variety of different form factors and configurations. Some artificial-reality systems may be designed to work without near-eye displays (NEDs). Other artificial-reality systems may include an NED that also provides visibility into the real world (such as, e.g., augmented-reality system  1300  in  FIG. 13 ) or that visually immerses a user in an artificial reality (such as, e.g., virtual-reality system  1400  in  FIG. 14 ). While some artificial-reality devices may be self-contained systems, other artificial-reality devices may communicate and/or coordinate with external devices to provide an artificial-reality experience to a user. Examples of such external devices include handheld controllers, mobile devices, desktop computers, devices worn by a user, devices worn by one or more other users, and/or any other suitable external system. 
     Turning to  FIG. 13 , augmented-reality system  1300  may include an eyewear device  1302  with a frame  1310  configured to hold a left display device  1315 (A) and a right display device  1315 (B) in front of a user&#39;s eyes. Display devices  1315 (A) and  1315 (B) may act together or independently to present an image or series of images to a user. While augmented-reality system  1300  includes two displays, embodiments of this disclosure may be implemented in augmented-reality systems with a single NED or more than two NEDs. 
     In some embodiments, augmented-reality system  1300  may include one or more sensors, such as sensor  1340 . Sensor  1340  may generate measurement signals in response to motion of augmented-reality system  1300  and may be located on substantially any portion of frame  1310 . Sensor  1340  may represent one or more of a variety of different sensing mechanisms, such as a position sensor, an inertial measurement unit (IMU), a depth camera assembly, a structured light emitter and/or detector, or any combination thereof. In some embodiments, augmented-reality system  1300  may or may not include sensor  1340  or may include more than one sensor. In embodiments in which sensor  1340  includes an IMU, the IMU may generate calibration data based on measurement signals from sensor  1340 . Examples of sensor  1340  may include, without limitation, accelerometers, gyroscopes, magnetometers, other suitable types of sensors that detect motion, sensors used for error correction of the IMU, or some combination thereof. 
     In some examples, augmented-reality system  1300  may also include a microphone array with a plurality of acoustic transducers  1320 (A)- 1320 (J), referred to collectively as acoustic transducers  1320 . Acoustic transducers  1320  may represent transducers that detect air pressure variations induced by sound waves. Each acoustic transducer  1320  may be configured to detect sound and convert the detected sound into an electronic format (e.g., an analog or digital format). The microphone array in  FIG. 13  may include, for example, ten acoustic transducers:  1320 (A) and  1320 (B), which may be designed to be placed inside a corresponding ear of the user, acoustic transducers  1320 (C),  1320 (D),  1320 (E),  1320 (F),  1320 (G), and  1320 (H), which may be positioned at various locations on frame  1310 , and/or acoustic transducers  1320 (I) and  1320 (J), which may be positioned on a corresponding neckband  135 . 
     In some embodiments, one or more of acoustic transducers  1320 (A)-(J) may be used as output transducers (e.g., speakers). For example, acoustic transducers  1320 (A) and/or  1320 (B) may be earbuds or any other suitable type of headphone or speaker. 
     The configuration of acoustic transducers  1320  of the microphone array may vary. While augmented-reality system  1300  is shown in  FIG. 13  as having ten acoustic transducers  1320 , the number of acoustic transducers  1320  may be greater or less than ten. In some embodiments, using higher numbers of acoustic transducers  1320  may increase the amount of audio information collected and/or the sensitivity and accuracy of the audio information. In contrast, using a lower number of acoustic transducers  1320  may decrease the computing power required by an associated controller  1350  to process the collected audio information. In addition, the position of each acoustic transducer  1320  of the microphone array may vary. For example, the position of an acoustic transducer  1320  may include a defined position on the user, a defined coordinate on frame  1310 , an orientation associated with each acoustic transducer  1320 , or some combination thereof. 
     Acoustic transducers  1320 (A) and  1320 (B) may be positioned on different parts of the user&#39;s ear, such as behind the pinna, behind the tragus, and/or within the auricle or fossa. Or, there may be additional acoustic transducers  1320  on or surrounding the ear in addition to acoustic transducers  1320  inside the ear canal. Having an acoustic transducer  1320  positioned next to an ear canal of a user may enable the microphone array to collect information on how sounds arrive at the ear canal. By positioning at least two of acoustic transducers  1320  on either side of a user&#39;s head (e.g., as binaural microphones), augmented-reality device  1300  may simulate binaural hearing and capture a 3D stereo sound field around about a user&#39;s head. In some embodiments, acoustic transducers  1320 (A) and  1320 (B) may be connected to augmented-reality system  1300  via a wired connection  1330 , and in other embodiments acoustic transducers  1320 (A) and  1320 (B) may be connected to augmented-reality system  1300  via a wireless connection (e.g., a BLUETOOTH connection). In still other embodiments, acoustic transducers  1320 (A) and  1320 (B) may not be used at all in conjunction with augmented-reality system  1300 . 
     Acoustic transducers  1320  on frame  1310  may be positioned in a variety of different ways, including along the length of the temples, across the bridge, above or below display devices  1315 (A) and  1315 (B), or some combination thereof. Acoustic transducers  1320  may also be oriented such that the microphone array is able to detect sounds in a wide range of directions surrounding the user wearing the augmented-reality system  1300 . In some embodiments, an optimization process may be performed during manufacturing of augmented-reality system  1300  to determine relative positioning of each acoustic transducer  1320  in the microphone array. 
     In some examples, augmented-reality system  1300  may include or be connected to an external device (e.g., a paired device), such as neckband  135 . Neckband  135  generally represents any type or form of paired device. Thus, the following discussion of neckband  135  may also apply to various other paired devices, such as charging cases, smart watches, smart phones, wrist bands, other wearable devices, hand-held controllers, tablet computers, laptop computers, other external compute devices, etc. 
     As shown, neckband  135  may be coupled to eyewear device  1302  via one or more connectors. The connectors may be wired or wireless and may include electrical and/or non-electrical (e.g., structural) components. In some cases, eyewear device  1302  and neckband  135  may operate independently without any wired or wireless connection between them. While  FIG. 13  illustrates the components of eyewear device  1302  and neckband  135  in example locations on eyewear device  1302  and neckband  135 , the components may be located elsewhere and/or distributed differently on eyewear device  1302  and/or neckband  135 . In some embodiments, the components of eyewear device  1302  and neckband  135  may be located on one or more additional peripheral devices paired with eyewear device  1302 , neckband  135 , or some combination thereof. 
     Pairing external devices, such as neckband  135 , with augmented-reality eyewear devices may enable the eyewear devices to achieve the form factor of a pair of glasses while still providing sufficient battery and computation power for expanded capabilities. Some or all of the battery power, computational resources, and/or additional features of augmented-reality system  1300  may be provided by a paired device or shared between a paired device and an eyewear device, thus reducing the weight, heat profile, and form factor of the eyewear device overall while still retaining desired functionality. For example, neckband  135  may allow components that would otherwise be included on an eyewear device to be included in neckband  135  since users may tolerate a heavier weight load on their shoulders than they would tolerate on their heads. Neckband  135  may also have a larger surface area over which to diffuse and disperse heat to the ambient environment. Thus, neckband  135  may allow for greater battery and computation capacity than might otherwise have been possible on a stand-alone eyewear device. Since weight carried in neckband  135  may be less invasive to a user than weight carried in eyewear device  1302 , a user may tolerate wearing a lighter eyewear device and carrying or wearing the paired device for greater lengths of time than a user would tolerate wearing a heavy standalone eyewear device, thereby enabling users to more fully incorporate artificial-reality environments into their day-to-day activities. 
     Neckband  135  may be communicatively coupled with eyewear device  1302  and/or to other devices. These other devices may provide certain functions (e.g., tracking, localizing, depth mapping, processing, storage, etc.) to augmented-reality system  1300 . In the embodiment of  FIG. 13 , neckband  135  may include two acoustic transducers (e.g.,  1320 (I) and  1320 (J)) that are part of the microphone array (or potentially form their own microphone subarray). Neckband  135  may also include a controller  1325  and a power source  1335 . 
     Acoustic transducers  1320 (I) and  1320 (J) of neckband  135  may be configured to detect sound and convert the detected sound into an electronic format (analog or digital). In the embodiment of  FIG. 13 , acoustic transducers  1320 (I) and  1320 (J) may be positioned on neckband  135 , thereby increasing the distance between the neckband acoustic transducers  1320 (I) and  1320 (J) and other acoustic transducers  1320  positioned on eyewear device  1302 . In some cases, increasing the distance between acoustic transducers  1320  of the microphone array may improve the accuracy of beamforming performed via the microphone array. For example, if a sound is detected by acoustic transducers  1320 (C) and  1320 (D) and the distance between acoustic transducers  1320 (C) and  1320 (D) is greater than, e.g., the distance between acoustic transducers  1320 (D) and  1320 (E), the determined source location of the detected sound may be more accurate than if the sound had been detected by acoustic transducers  1320 (D) and  1320 (E). 
     Controller  1325  of neckband  135  may process information generated by the sensors on neckband  135  and/or augmented-reality system  1300 . For example, controller  1325  may process information from the microphone array that describes sounds detected by the microphone array. For each detected sound, controller  1325  may perform a direction-of-arrival (DOA) estimation to estimate a direction from which the detected sound arrived at the microphone array. As the microphone array detects sounds, controller  1325  may populate an audio data set with the information. In embodiments in which augmented-reality system  1300  includes an inertial measurement unit, controller  1325  may compute all inertial and spatial calculations from the IMU located on eyewear device  1302 . A connector may convey information between augmented-reality system  1300  and neckband  135  and between augmented-reality system  1300  and controller  1325 . The information may be in the form of optical data, electrical data, wireless data, or any other transmittable data form. Moving the processing of information generated by augmented-reality system  1300  to neckband  135  may reduce weight and heat in eyewear device  1302 , making it more comfortable to the user. 
     Power source  1335  in neckband  135  may provide power to eyewear device  1302  and/or to neckband  135 . Power source  1335  may include, without limitation, lithium ion batteries, lithium-polymer batteries, primary lithium batteries, alkaline batteries, or any other form of power storage. In some cases, power source  1335  may be a wired power source. Including power source  1335  on neckband  135  instead of on eyewear device  1302  may help better distribute the weight and heat generated by power source  1335 . 
     As noted, some artificial-reality systems may, instead of blending an artificial reality with actual reality, substantially replace one or more of a user&#39;s sensory perceptions of the real world with a virtual experience. One example of this type of system is a head-worn display system, such as virtual-reality system  1400  in  FIG. 14 , that mostly or completely covers a user&#39;s field of view. Virtual-reality system  1400  may include a front rigid body  1402  and a band  144  shaped to fit around a user&#39;s head. Virtual-reality system  1400  may also include output audio transducers  146 (A) and  146 (B). Furthermore, while not shown in  FIG. 14 , front rigid body  1402  may include one or more electronic elements, including one or more electronic displays, one or more inertial measurement units (IMUs), one or more tracking emitters or detectors, and/or any other suitable device or system for creating an artificial-reality experience. 
     Artificial-reality systems may include a variety of types of visual feedback mechanisms. For example, display devices in augmented-reality system  1300  and/or virtual-reality system  1400  may include one or more liquid crystal displays (LCDs), light emitting diode (LED) displays, microLED displays, organic LED (OLED) displays, digital light project (DLP) micro-displays, liquid crystal on silicon (LCoS) micro-displays, and/or any other suitable type of display screen. These artificial-reality systems may include a single display screen for both eyes or may provide a display screen for each eye, which may allow for additional flexibility for varifocal adjustments or for correcting a user&#39;s refractive error. Some of these artificial-reality systems may also include optical subsystems having one or more lenses (e.g., concave or convex lenses, Fresnel lenses, adjustable liquid lenses, etc.) through which a user may view a display screen. These optical subsystems may serve a variety of purposes, including to collimate (e.g., make an object appear at a greater distance than its physical distance), to magnify (e.g., make an object appear larger than its actual size), and/or to relay (to, e.g., the viewer&#39;s eyes) light. These optical subsystems may be used in a non-pupil-forming architecture (such as a single lens configuration that directly collimates light but results in so-called pincushion distortion) and/or a pupil-forming architecture (such as a multi-lens configuration that produces so-called barrel distortion to nullify pincushion distortion). 
     In addition to or instead of using display screens, some of the artificial-reality systems described herein may include one or more projection systems. For example, display devices in augmented-reality system  1300  and/or virtual-reality system  1400  may include micro-LED projectors that project light (using, e.g., a waveguide) into display devices, such as clear combiner lenses that allow ambient light to pass through. The display devices may refract the projected light toward a user&#39;s pupil and may enable a user to simultaneously view both artificial-reality content and the real world. The display devices may accomplish this using any of a variety of different optical components, including waveguide components (e.g., holographic, planar, diffractive, polarized, and/or reflective waveguide elements), light-manipulation surfaces and elements (such as diffractive, reflective, and refractive elements and gratings), coupling elements, etc. Artificial-reality systems may also be configured with any other suitable type or form of image projection system, such as retinal projectors used in virtual retina displays. 
     The artificial-reality systems described herein may also include various types of computer vision components and subsystems. For example, augmented-reality system  1300  and/or virtual-reality system  1400  may include one or more optical sensors, such as two-dimensional (2D) or 3D cameras, structured light transmitters and detectors, time-of-flight depth sensors, single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. An artificial-reality system may process data from one or more of these sensors to identify a location of a user, to map the real world, to provide a user with context about real-world surroundings, and/or to perform a variety of other functions. 
     The artificial-reality systems described herein may also include one or more input and/or output audio transducers. Output audio transducers may include voice coil speakers, ribbon speakers, electrostatic speakers, piezoelectric speakers, bone conduction transducers, cartilage conduction transducers, tragus-vibration transducers, and/or any other suitable type or form of audio transducer. Similarly, input audio transducers may include condenser microphones, dynamic microphones, ribbon microphones, and/or any other type or form of input transducer. In some embodiments, a single transducer may be used for both audio input and audio output. 
     In some embodiments, the artificial-reality systems described herein may also include tactile (i.e., haptic) feedback systems, which may be incorporated into headwear, gloves, body suits, handheld controllers, environmental devices (e.g., chairs, floormats, etc.), and/or any other type of device or system. Haptic feedback systems may provide various types of cutaneous feedback, including vibration, force, traction, texture, and/or temperature. Haptic feedback systems may also provide various types of kinesthetic feedback, such as motion and compliance. Haptic feedback may be implemented using motors, piezoelectric actuators, fluidic systems, and/or a variety of other types of feedback mechanisms. Haptic feedback systems may be implemented independent of other artificial-reality devices, within other artificial-reality devices, and/or in conjunction with other artificial-reality devices. 
     By providing haptic sensations, audible content, and/or visual content, artificial-reality systems may create an entire virtual experience or enhance a user&#39;s real-world experience in a variety of contexts and environments. For instance, artificial-reality systems may assist or extend a user&#39;s perception, memory, or cognition within a particular environment. Some systems may enhance a user&#39;s interactions with other people in the real world or may enable more immersive interactions with other people in a virtual world. Artificial-reality systems may also be used for educational purposes (e.g., for teaching or training in schools, hospitals, government organizations, military organizations, business enterprises, etc.), entertainment purposes (e.g., for playing video games, listening to music, watching video content, etc.), and/or for accessibility purposes (e.g., as hearing aids, visual aids, etc.). The embodiments disclosed herein may enable or enhance a user&#39;s artificial-reality experience in one or more of these contexts and environments and/or in other contexts and environments. 
     Some augmented-reality systems may map a user&#39;s and/or device&#39;s environment using techniques referred to as “simultaneous location and mapping” (SLAM). SLAM mapping and location identifying techniques may involve a variety of hardware and software tools that can create or update a map of an environment while simultaneously keeping track of a user&#39;s location within the mapped environment. SLAM may use many different types of sensors to create a map and determine a user&#39;s position within the map. 
     SLAM techniques may, for example, implement optical sensors to determine a user&#39;s location. Radios including WiFi, BLUETOOTH, global positioning system (GPS), cellular or other communication devices may be also used to determine a user&#39;s location relative to a radio transceiver or group of transceivers (e.g., a WiFi router or group of GPS satellites). Acoustic sensors such as microphone arrays or 2D or 3D sonar sensors may also be used to determine a user&#39;s location within an environment. Augmented-reality and virtual-reality devices (such as systems  1300  and  1400  of  FIGS. 13 and 14 , respectively) may incorporate any or all of these types of sensors to perform SLAM operations such as creating and continually updating maps of the user&#39;s current environment. In at least some of the embodiments described herein, SLAM data generated by these sensors may be referred to as “environmental data” and may indicate a user&#39;s current environment. This data may be stored in a local or remote data store (e.g., a cloud data store) and may be provided to a user&#39;s AR/VR device on demand. 
     As noted, artificial-reality systems  1300  and  1400  may be used with a variety of other types of devices to provide a more compelling artificial-reality experience. These devices may be haptic interfaces with transducers that provide haptic feedback and/or that collect haptic information about a user&#39;s interaction with an environment. The artificial-reality systems disclosed herein may include various types of haptic interfaces that detect or convey various types of haptic information, including tactile feedback (e.g., feedback that a user detects via nerves in the skin, which may also be referred to as cutaneous feedback) and/or kinesthetic feedback (e.g., feedback that a user detects via receptors located in muscles, joints, and/or tendons). 
     Haptic feedback may be provided by interfaces positioned within a user&#39;s environment (e.g., chairs, tables, floors, etc.) and/or interfaces on articles that may be worn or carried by a user (e.g., gloves, wristbands, etc.). As an example,  FIG. 15  illustrates a vibrotactile system  1500  in the form of a wearable glove (haptic device  1510 ) and wristband (haptic device  1520 ). Haptic device  1510  and haptic device  1520  are shown as examples of wearable devices that include a flexible, wearable textile material  1530  that is shaped and configured for positioning against a user&#39;s hand and wrist, respectively. This disclosure also includes vibrotactile systems that may be shaped and configured for positioning against other human body parts, such as a finger, an arm, a head, a torso, a foot, or a leg. By way of example and not limitation, vibrotactile systems according to various embodiments of the present disclosure may also be in the form of a glove, a headband, an armband, a sleeve, a head covering, a sock, a shirt, or pants, among other possibilities. In some examples, the term “textile” may include any flexible, wearable material, including woven fabric, non-woven fabric, leather, cloth, a flexible polymer material, composite materials, etc. 
     One or more vibrotactile devices  1540  may be positioned at least partially within one or more corresponding pockets formed in textile material  1530  of vibrotactile system  1500 . Vibrotactile devices  1540  may be positioned in locations to provide a vibrating sensation (e.g., haptic feedback) to a user of vibrotactile system  1500 . For example, vibrotactile devices  1540  may be positioned against the user&#39;s finger(s), thumb, or wrist, as shown in  FIG. 15 . Vibrotactile devices  1540  may, in some examples, be sufficiently flexible to conform to or bend with the user&#39;s corresponding body part(s). 
     A power source  1550  (e.g., a battery) for applying a voltage to the vibrotactile devices  1540  for activation thereof may be electrically coupled to vibrotactile devices  1540 , such as via conductive wiring  1552 . In some examples, each of vibrotactile devices  1540  may be independently electrically coupled to power source  1550  for individual activation. In some embodiments, a processor  1560  may be operatively coupled to power source  1550  and configured (e.g., programmed) to control activation of vibrotactile devices  1540 . 
     Vibrotactile system  1500  may be implemented in a variety of ways. In some examples, vibrotactile system  1500  may be a standalone system with integral subsystems and components for operation independent of other devices and systems. As another example, vibrotactile system  1500  may be configured for interaction with another device or system  1570 . For example, vibrotactile system  1500  may, in some examples, include a communications interface  1580  for receiving and/or sending signals to the other device or system  1570 . The other device or system  1570  may be a mobile device, a gaming console, an artificial-reality (e.g., virtual-reality, augmented-reality, mixed-reality) device, a personal computer, a tablet computer, a network device (e.g., a modem, a router, etc.), a handheld controller, etc. Communications interface  1580  may enable communications between vibrotactile system  1500  and the other device or system  1570  via a wireless (e.g., Wi-Fi, BLUETOOTH, cellular, radio, etc.) link or a wired link. If present, communications interface  1580  may be in communication with processor  1560 , such as to provide a signal to processor  1560  to activate or deactivate one or more of the vibrotactile devices  1540 . 
     Vibrotactile system  1500  may optionally include other subsystems and components, such as touch-sensitive pads  1590 , pressure sensors, motion sensors, position sensors, lighting elements, and/or user interface elements (e.g., an on/off button, a vibration control element, etc.). During use, vibrotactile devices  1540  may be configured to be activated for a variety of different reasons, such as in response to the user&#39;s interaction with user interface elements, a signal from the motion or position sensors, a signal from the touch-sensitive pads  1590 , a signal from the pressure sensors, a signal from the other device or system  1570 , etc. 
     Although power source  1550 , processor  1560 , and communications interface  1580  are illustrated in  FIG. 15  as being positioned in haptic device  1520 , the present disclosure is not so limited. For example, one or more of power source  1550 , processor  1560 , or communications interface  1580  may be positioned within haptic device  1510  or within another wearable textile. 
     Haptic wearables, such as those shown in and described in connection with  FIG. 15 , may be implemented in a variety of types of artificial-reality systems and environments.  FIG. 16  shows an example artificial-reality environment  1600  including one head-mounted virtual-reality display and two haptic devices (i.e., gloves), and in other embodiments any number and/or combination of these components and other components may be included in an artificial-reality system. For example, in some embodiments there may be multiple head-mounted displays each having an associated haptic device, with each head-mounted display and each haptic device communicating with the same console, portable computing device, or other computing system. 
     Head-mounted display  1602  generally represents any type or form of virtual-reality system, such as virtual-reality system  1400  in  FIG. 14 . Haptic device  164  generally represents any type or form of wearable device, worn by a user of an artificial-reality system, that provides haptic feedback to the user to give the user the perception that he or she is physically engaging with a virtual object. In some embodiments, haptic device  164  may provide haptic feedback by applying vibration, motion, and/or force to the user. For example, haptic device  164  may limit or augment a user&#39;s movement. To give a specific example, haptic device  164  may limit a user&#39;s hand from moving forward so that the user has the perception that his or her hand has come in physical contact with a virtual wall. In this specific example, one or more actuators within the haptic device may achieve the physical-movement restriction by pumping fluid into an inflatable bladder of the haptic device. In some examples, a user may also use haptic device  164  to send action requests to a console. Examples of action requests include, without limitation, requests to start an application and/or end the application and/or requests to perform a particular action within the application. 
     While haptic interfaces may be used with virtual-reality systems, as shown in  FIG. 16 , haptic interfaces may also be used with augmented-reality systems, as shown in  FIG. 17 .  FIG. 17  is a perspective view of a user  1710  interacting with an augmented-reality system  1700 . In this example, user  1710  may wear a pair of augmented-reality glasses  1720  that may have one or more displays  1722  and that are paired with a haptic device  1730 . In this example, haptic device  1730  may be a wristband that includes a plurality of band elements  1732  and a tensioning mechanism  1734  that connects band elements  1732  to one another. 
     One or more of band elements  1732  may include any type or form of actuator suitable for providing haptic feedback. For example, one or more of band elements  1732  may be configured to provide one or more of various types of cutaneous feedback, including vibration, force, traction, texture, and/or temperature. To provide such feedback, band elements  1732  may include one or more of various types of actuators. In one example, each of band elements  1732  may include a vibrotactor (e.g., a vibrotactile actuator) configured to vibrate in unison or independently to provide one or more of various types of haptic sensations to a user. Alternatively, only a single band element or a subset of band elements may include vibrotactors. 
     Haptic devices  1510 ,  1520 ,  164 , and  1730  may include any suitable number and/or type of haptic transducer, sensor, and/or feedback mechanism. For example, haptic devices  1510 ,  1520 ,  164 , and  1730  may include one or more mechanical transducers, piezoelectric transducers, and/or fluidic transducers. Haptic devices  1510 ,  1520 ,  164 , and  1730  may also include various combinations of different types and forms of transducers that work together or independently to enhance a user&#39;s artificial-reality experience. In one example, each of band elements  1732  of haptic device  1730  may include a vibrotactor (e.g., a vibrotactile actuator) configured to vibrate in unison or independently to provide one or more of various types of haptic sensations to a user. 
     In some embodiments, the systems described herein may also include an eye-tracking subsystem designed to identify and track various characteristics of a user&#39;s eye(s), such as the user&#39;s gaze direction. The phrase “eye tracking” may, in some examples, refer to a process by which the position, orientation, and/or motion of an eye is measured, detected, sensed, determined, and/or monitored. The disclosed systems may measure the position, orientation, and/or motion of an eye in a variety of different ways, including through the use of various optical-based eye-tracking techniques, ultrasound-based eye-tracking techniques, etc. An eye-tracking subsystem may be configured in a number of different ways and may include a variety of different eye-tracking hardware components or other computer-vision components. For example, an eye-tracking subsystem may include a variety of different optical sensors, such as two-dimensional ( 2 D) or 3D cameras, time-of-flight depth sensors, single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. In this example, a processing subsystem may process data from one or more of these sensors to measure, detect, determine, and/or otherwise monitor the position, orientation, and/or motion of the user&#39;s eye(s). 
       FIG. 18  is an illustration of an exemplary system  1800  that incorporates an eye-tracking subsystem capable of tracking a user&#39;s eye(s). As depicted in  FIG. 18 , system  1800  may include a light source  1802 , an optical subsystem  184 , an eye-tracking subsystem  186 , and/or a control subsystem  188 . In some examples, light source  1802  may generate light for an image (e.g., to be presented to an eye  1801  of the viewer). Light source  1802  may represent any of a variety of suitable devices. For example, light source  1802  can include a two-dimensional projector (e.g., a LCoS display), a scanning source (e.g., a scanning laser), or other device (e.g., an LCD, an LED display, an OLED display, an active-matrix OLED display (AMOLED), a transparent OLED display (TOLED), a waveguide, or some other display capable of generating light for presenting an image to the viewer). In some examples, the image may represent a virtual image, which may refer to an optical image formed from the apparent divergence of light rays from a point in space, as opposed to an image formed from the light ray&#39;s actual divergence. 
     In some embodiments, optical subsystem  184  may receive the light generated by light source  1802  and generate, based on the received light, converging light  1820  that includes the image. In some examples, optical subsystem  184  may include any number of lenses (e.g., Fresnel lenses, convex lenses, concave lenses), apertures, filters, mirrors, prisms, and/or other optical components, possibly in combination with actuators and/or other devices. In particular, the actuators and/or other devices may translate and/or rotate one or more of the optical components to alter one or more aspects of converging light  1820 . Further, various mechanical couplings may serve to maintain the relative spacing and/or the orientation of the optical components in any suitable combination. 
     In one embodiment, eye-tracking subsystem  186  may generate tracking information indicating a gaze angle of an eye  1801  of the viewer. In this embodiment, control subsystem  188  may control aspects of optical subsystem  184  (e.g., the angle of incidence of converging light  1820 ) based at least in part on this tracking information. Additionally, in some examples, control subsystem  188  may store and utilize historical tracking information (e.g., a history of the tracking information over a given duration, such as the previous second or fraction thereof) to anticipate the gaze angle of eye  1801  (e.g., an angle between the visual axis and the anatomical axis of eye  1801 ). In some embodiments, eye-tracking subsystem  186  may detect radiation emanating from some portion of eye  1801  (e.g., the cornea, the iris, the pupil, or the like) to determine the current gaze angle of eye  1801 . In other examples, eye-tracking subsystem  186  may employ a wavefront sensor to track the current location of the pupil. 
     Any number of techniques can be used to track eye  1801 . Some techniques may involve illuminating eye  1801  with infrared light and measuring reflections with at least one optical sensor that is tuned to be sensitive to the infrared light. Information about how the infrared light is reflected from eye  1801  may be analyzed to determine the position(s), orientation(s), and/or motion(s) of one or more eye feature(s), such as the cornea, pupil, iris, and/or retinal blood vessels. 
     In some examples, the radiation captured by a sensor of eye-tracking subsystem  186  may be digitized (i.e., converted to an electronic signal). Further, the sensor may transmit a digital representation of this electronic signal to one or more processors (for example, processors associated with a device including eye-tracking subsystem  186 ). Eye-tracking subsystem  186  may include any of a variety of sensors in a variety of different configurations. For example, eye-tracking subsystem  186  may include an infrared detector that reacts to infrared radiation. The infrared detector may be a thermal detector, a photonic detector, and/or any other suitable type of detector. Thermal detectors may include detectors that react to thermal effects of the incident infrared radiation. 
     In some examples, one or more processors may process the digital representation generated by the sensor(s) of eye-tracking subsystem  186  to track the movement of eye  1801 . In another example, these processors may track the movements of eye  1801  by executing algorithms represented by computer-executable instructions stored on non-transitory memory. In some examples, on-chip logic (e.g., an application-specific integrated circuit or ASIC) may be used to perform at least portions of such algorithms. As noted, eye-tracking subsystem  186  may be programmed to use an output of the sensor(s) to track movement of eye  1801 . In some embodiments, eye-tracking subsystem  186  may analyze the digital representation generated by the sensors to extract eye rotation information from changes in reflections. In one embodiment, eye-tracking subsystem  186  may use corneal reflections or glints (also known as Purkinje images) and/or the center of the eye&#39;s pupil  1822  as features to track over time. 
     In some embodiments, eye-tracking subsystem  186  may use the center of the eye&#39;s pupil  1822  and infrared or near-infrared, non-collimated light to create corneal reflections. In these embodiments, eye-tracking subsystem  186  may use the vector between the center of the eye&#39;s pupil  1822  and the corneal reflections to compute the gaze direction of eye  1801 . In some embodiments, the disclosed systems may perform a calibration procedure for an individual (using, e.g., supervised or unsupervised techniques) before tracking the user&#39;s eyes. For example, the calibration procedure may include directing users to look at one or more points displayed on a display while the eye-tracking system records the values that correspond to each gaze position associated with each point. 
     In some embodiments, eye-tracking subsystem  186  may use two types of infrared and/or near-infrared (also known as active light) eye-tracking techniques: bright-pupil and dark-pupil eye tracking, which may be differentiated based on the location of an illumination source with respect to the optical elements used. If the illumination is coaxial with the optical path, then eye  1801  may act as a retroreflector as the light reflects off the retina, thereby creating a bright pupil effect similar to a red-eye effect in photography. If the illumination source is offset from the optical path, then the eye&#39;s pupil  1822  may appear dark because the retroreflection from the retina is directed away from the sensor. In some embodiments, bright-pupil tracking may create greater iris/pupil contrast, allowing more robust eye tracking with iris pigmentation, and may feature reduced interference (e.g., interference caused by eyelashes and other obscuring features). Bright-pupil tracking may also allow tracking in lighting conditions ranging from total darkness to a very bright environment. 
     In some embodiments, control subsystem  188  may control light source  1802  and/or optical subsystem  184  to reduce optical aberrations (e.g., chromatic aberrations and/or monochromatic aberrations) of the image that may be caused by or influenced by eye  1801 . In some examples, as mentioned above, control subsystem  188  may use the tracking information from eye-tracking subsystem  186  to perform such control. For example, in controlling light source  1802 , control subsystem  188  may alter the light generated by light source  1802  (e.g., by way of image rendering) to modify (e.g., pre-distort) the image so that the aberration of the image caused by eye  1801  is reduced. 
     The disclosed systems may track both the position and relative size of the pupil (since, e.g., the pupil dilates and/or contracts). In some examples, the eye-tracking devices and components (e.g., sensors and/or sources) used for detecting and/or tracking the pupil may be different (or calibrated differently) for different types of eyes. For example, the frequency range of the sensors may be different (or separately calibrated) for eyes of different colors and/or different pupil types, sizes, and/or the like. As such, the various eye-tracking components (e.g., infrared sources and/or sensors) described herein may need to be calibrated for each individual user and/or eye. 
     The disclosed systems may track both eyes with and without ophthalmic correction, such as that provided by contact lenses worn by the user. In some embodiments, ophthalmic correction elements (e.g., adjustable lenses) may be directly incorporated into the artificial reality systems described herein. In some examples, the color of the user&#39;s eye may necessitate modification of a corresponding eye-tracking algorithm. For example, eye-tracking algorithms may need to be modified based at least in part on the differing color contrast between a brown eye and, for example, a blue eye. 
       FIG. 19  is a more detailed illustration of various aspects of the eye-tracking subsystem illustrated in  FIG. 18 . As shown in this figure, an eye-tracking subsystem  1900  may include at least one source  194  and at least one sensor  196 . Source  194  generally represents any type or form of element capable of emitting radiation. In one example, source  194  may generate visible, infrared, and/or near-infrared radiation. In some examples, source  194  may radiate non-collimated infrared and/or near-infrared portions of the electromagnetic spectrum towards an eye  1902  of a user. Source  194  may utilize a variety of sampling rates and speeds. For example, the disclosed systems may use sources with higher sampling rates in order to capture fixational eye movements of a user&#39;s eye  1902  and/or to correctly measure saccade dynamics of the user&#39;s eye  1902 . As noted above, any type or form of eye-tracking technique may be used to track the user&#39;s eye  1902 , including optical-based eye-tracking techniques, ultrasound-based eye-tracking techniques, etc. 
     Sensor  196  generally represents any type or form of element capable of detecting radiation, such as radiation reflected off the user&#39;s eye  1902 . Examples of sensor  196  include, without limitation, a charge coupled device (CCD), a photodiode array, a complementary metal-oxide-semiconductor (CMOS) based sensor device, and/or the like. In one example, sensor  196  may represent a sensor having predetermined parameters, including, but not limited to, a dynamic resolution range, linearity, and/or other characteristic selected and/or designed specifically for eye tracking. 
     As detailed above, eye-tracking subsystem  1900  may generate one or more glints. As detailed above, a glint  193  may represent reflections of radiation (e.g., infrared radiation from an infrared source, such as source  194 ) from the structure of the user&#39;s eye. In various embodiments, glint  193  and/or the user&#39;s pupil may be tracked using an eye-tracking algorithm executed by a processor (either within or external to an artificial reality device). For example, an artificial reality device may include a processor and/or a memory device in order to perform eye tracking locally and/or a transceiver to send and receive the data necessary to perform eye tracking on an external device (e.g., a mobile phone, cloud server, or other computing device). 
       FIG. 19  shows an example image  195  captured by an eye-tracking subsystem, such as eye-tracking subsystem  1900 . In this example, image  195  may include both the user&#39;s pupil  198  and a glint  1910  near the same. In some examples, pupil  198  and/or glint  1910  may be identified using an artificial-intelligence-based algorithm, such as a computer-vision-based algorithm. In one embodiment, image  195  may represent a single frame in a series of frames that may be analyzed continuously in order to track the eye  1902  of the user. Further, pupil  198  and/or glint  1910  may be tracked over a period of time to determine a user&#39;s gaze. 
     In one example, eye-tracking subsystem  1900  may be configured to identify and measure the inter-pupillary distance (IPD) of a user. In some embodiments, eye-tracking subsystem  1900  may measure and/or calculate the IPD of the user while the user is wearing the artificial reality system. In these embodiments, eye-tracking subsystem  1900  may detect the positions of a user&#39;s eyes and may use this information to calculate the user&#39;s IPD. 
     As noted, the eye-tracking systems or subsystems disclosed herein may track a user&#39;s eye position and/or eye movement in a variety of ways. In one example, one or more light sources and/or optical sensors may capture an image of the user&#39;s eyes. The eye-tracking subsystem may then use the captured information to determine the user&#39;s inter-pupillary distance, interocular distance, and/or a 3D position of each eye (e.g., for distortion adjustment purposes), including a magnitude of torsion and rotation (i.e., roll, pitch, and yaw) and/or gaze directions for each eye. In one example, infrared light may be emitted by the eye-tracking subsystem and reflected from each eye. The reflected light may be received or detected by an optical sensor and analyzed to extract eye rotation data from changes in the infrared light reflected by each eye. 
     The eye-tracking subsystem may use any of a variety of different methods to track the eyes of a user. For example, a light source (e.g., infrared light-emitting diodes) may emit a dot pattern onto each eye of the user. The eye-tracking subsystem may then detect (e.g., via an optical sensor coupled to the artificial reality system) and analyze a reflection of the dot pattern from each eye of the user to identify a location of each pupil of the user. Accordingly, the eye-tracking subsystem may track up to six degrees of freedom of each eye (i.e., 3D position, roll, pitch, and yaw) and at least a subset of the tracked quantities may be combined from two eyes of a user to estimate a gaze point (i.e., a 3D location or position in a virtual scene where the user is looking) and/or an IPD. 
     In some cases, the distance between a user&#39;s pupil and a display may change as the user&#39;s eye moves to look in different directions. The varying distance between a pupil and a display as viewing direction changes may be referred to as “pupil swim” and may contribute to distortion perceived by the user as a result of light focusing in different locations as the distance between the pupil and the display changes. Accordingly, measuring distortion at different eye positions and pupil distances relative to displays and generating distortion corrections for different positions and distances may allow mitigation of distortion caused by pupil swim by tracking the 3D position of a user&#39;s eyes and applying a distortion correction corresponding to the 3D position of each of the user&#39;s eyes at a given point in time. Thus, knowing the 3D position of each of a user&#39;s eyes may allow for the mitigation of distortion caused by changes in the distance between the pupil of the eye and the display by applying a distortion correction for each 3D eye position. Furthermore, as noted above, knowing the position of each of the user&#39;s eyes may also enable the eye-tracking subsystem to make automated adjustments for a user&#39;s IPD. 
     In some embodiments, a display subsystem may include a variety of additional subsystems that may work in conjunction with the eye-tracking subsystems described herein. For example, a display subsystem may include a varifocal subsystem, a scene-rendering module, and/or a vergence-processing module. The varifocal subsystem may cause left and right display elements to vary the focal distance of the display device. In one embodiment, the varifocal subsystem may physically change the distance between a display and the optics through which it is viewed by moving the display, the optics, or both. Additionally, moving or translating two lenses relative to each other may also be used to change the focal distance of the display. Thus, the varifocal subsystem may include actuators or motors that move displays and/or optics to change the distance between them. This varifocal subsystem may be separate from or integrated into the display subsystem. The varifocal subsystem may also be integrated into or separate from its actuation subsystem and/or the eye-tracking subsystems described herein. 
     In one example, the display subsystem may include a vergence-processing module configured to determine a vergence depth of a user&#39;s gaze based on a gaze point and/or an estimated intersection of the gaze lines determined by the eye-tracking subsystem. Vergence may refer to the simultaneous movement or rotation of both eyes in opposite directions to maintain single binocular vision, which may be naturally and automatically performed by the human eye. Thus, a location where a user&#39;s eyes are verged is where the user is looking and is also typically the location where the user&#39;s eyes are focused. For example, the vergence-processing module may triangulate gaze lines to estimate a distance or depth from the user associated with intersection of the gaze lines. The depth associated with intersection of the gaze lines may then be used as an approximation for the accommodation distance, which may identify a distance from the user where the user&#39;s eyes are directed. Thus, the vergence distance may allow for the determination of a location where the user&#39;s eyes should be focused and a depth from the user&#39;s eyes at which the eyes are focused, thereby providing information (such as an object or plane of focus) for rendering adjustments to the virtual scene. 
     The vergence-processing module may coordinate with the eye-tracking subsystems described herein to make adjustments to the display subsystem to account for a user&#39;s vergence depth. When the user is focused on something at a distance, the user&#39;s pupils may be slightly farther apart than when the user is focused on something close. The eye-tracking subsystem may obtain information about the user&#39;s vergence or focus depth and may adjust the display subsystem to be closer together when the user&#39;s eyes focus or verge on something close and to be farther apart when the user&#39;s eyes focus or verge on something at a distance. 
     The eye-tracking information generated by the above-described eye-tracking subsystems may also be used, for example, to modify various aspect of how different computer-generated images are presented. For example, a display subsystem may be configured to modify, based on information generated by an eye-tracking subsystem, at least one aspect of how the computer-generated images are presented. For instance, the computer-generated images may be modified based on the user&#39;s eye movement, such that if a user is looking up, the computer-generated images may be moved upward on the screen. Similarly, if the user is looking to the side or down, the computer-generated images may be moved to the side or downward on the screen. If the user&#39;s eyes are closed, the computer-generated images may be paused or removed from the display and resumed once the user&#39;s eyes are back open. 
     The above-described eye-tracking subsystems can be incorporated into one or more of the various artificial reality systems described herein in a variety of ways. For example, one or more of the various components of system  1800  and/or eye-tracking subsystem  1900  may be incorporated into augmented-reality system  1300  in  FIG. 13  and/or virtual-reality system  1400  in  FIG. 14  to enable these systems to perform various eye-tracking tasks (including one or more of the eye-tracking operations described herein). 
       FIG. 20A  illustrates an exemplary human-machine interface (also referred to herein as an EMG control interface) configured to be worn around a user&#39;s lower arm or wrist as a wearable system  2000 . In this example, wearable system  2000  may include sixteen neuromuscular sensors  2010  (e.g., EMG sensors) arranged circumferentially around an elastic band  2020  with an interior surface  2030  configured to contact a user&#39;s skin. However, any suitable number of neuromuscular sensors may be used. The number and arrangement of neuromuscular sensors may depend on the particular application for which the wearable device is used. For example, a wearable armband or wristband can be used to generate control information for controlling an augmented reality system, a robot, controlling a vehicle, scrolling through text, controlling a virtual avatar, or any other suitable control task. As shown, the sensors may be coupled together using flexible electronics incorporated into the wireless device.  FIG. 20B  illustrates a cross-sectional view through one of the sensors of the wearable device shown in  FIG. 20A . In some embodiments, the output of one or more of the sensing components can be optionally processed using hardware signal processing circuitry (e.g., to perform amplification, filtering, and/or rectification). In other embodiments, at least some signal processing of the output of the sensing components can be performed in software. Thus, signal processing of signals sampled by the sensors can be performed in hardware, software, or by any suitable combination of hardware and software, as aspects of the technology described herein are not limited in this respect. A non-limiting example of a signal processing chain used to process recorded data from sensors  2010  is discussed in more detail below with reference to  FIGS. 21A and 21B . 
       FIGS. 21A and 21B  illustrate an exemplary schematic diagram with internal components of a wearable system with EMG sensors. As shown, the wearable system may include a wearable portion  2110  ( FIG. 21A ) and a dongle portion  2120  ( FIG. 21B ) in communication with the wearable portion  2110  (e.g., via BLUETOOTH or another suitable wireless communication technology). As shown in  FIG. 21A , the wearable portion  2110  may include skin contact electrodes  2111 , examples of which are described in connection with  FIGS. 20A and 20B . The output of the skin contact electrodes  2111  may be provided to analog front end  2130 , which may be configured to perform analog processing (e.g., amplification, noise reduction, filtering, etc.) on the recorded signals. The processed analog signals may then be provided to analog-to-digital converter  2132 , which may convert the analog signals to digital signals that can be processed by one or more computer processors. An example of a computer processor that may be used in accordance with some embodiments is microcontroller (MCU)  2134 , illustrated in  FIG. 21A . As shown, MCU  2134  may also include inputs from other sensors (e.g., IMU sensor  2140 ), and power and battery module  2142 . The output of the processing performed by MCU  2134  may be provided to antenna  2150  for transmission to dongle portion  2120  shown in  FIG. 21B . 
     Dongle portion  2120  may include antenna  2152 , which may be configured to communicate with antenna  2150  included as part of wearable portion  2110 . Communication between antennas  2150  and  2152  may occur using any suitable wireless technology and protocol, non-limiting examples of which include radiofrequency signaling and BLUETOOTH. As shown, the signals received by antenna  2152  of dongle portion  2120  may be provided to a host computer for further processing, display, and/or for effecting control of a particular physical or virtual object or objects. 
     Although the examples provided with reference to  FIGS. 20A-20B  and  FIGS. 21A-21B  are discussed in the context of interfaces with EMG sensors, the techniques described herein for reducing electromagnetic interference can also be implemented in wearable interfaces with other types of sensors including, but not limited to, mechanomyography (MMG) sensors, sonomyography (SMG) sensors, and electrical impedance tomography (EIT) sensors. The techniques described herein for reducing electromagnetic interference can also be implemented in wearable interfaces that communicate with computer hosts through wires and cables (e.g., USB cables, optical fiber cables, etc.). 
       FIG. 22  schematically illustrates components of a biosignal sensing system  2200  in accordance with some embodiments. System  2200  includes a pair of electrodes  2210  (e.g., a pair of dry surface electrodes) configured to register or measure a biosignal (e.g., an Electrooculography (EOG) signal, an Electromyography (EMG) signal, a surface Electromyography (sEMG) signal, an Electroencephalography (EEG) signal, an Electrocardiography (ECG) signal, etc.) generated by the body of a user  2202  (e.g., for electrophysiological monitoring or stimulation). In some embodiments, both of electrodes  2210  may be contact electrodes configured to contact a user&#39;s skin. In other embodiments, both of electrodes  2210  may be non-contact electrodes configured to not contact a user&#39;s skin. Alternatively, one of electrodes  2210  may be a contact electrode configured to contact a user&#39;s skin, and the other one of electrodes  2210  may be a non-contact electrode configured to not contact the user&#39;s skin. In some embodiments, electrodes  2210  may be arranged as a portion of a wearable device configured to be worn on or around part of a user&#39;s body. For example, in one non-limiting example, a plurality of electrodes including electrodes  2210  may be arranged circumferentially around an adjustable and/or elastic band such as a wristband or armband configured to be worn around a user&#39;s wrist or arm (e.g., as illustrated in  FIG. 2 ). Additionally or alternatively, at least some of electrodes  2210  may be arranged on a wearable patch configured to be affixed to or placed in contact with a portion of the body of user  2202 . In some embodiments, the electrodes may be minimally invasive and may include one or more conductive components placed in or through all or part of the skin or dermis of the user. It should be appreciated that any suitable number of electrodes may be used, and the number and arrangement of electrodes may depend on the particular application for which a device is used. 
     Biosignals (e.g., biopotential signals) measured or recorded by electrodes  2210  may be small, and amplification of the biosignals recorded by electrodes  2210  may be desired. As shown in  FIG. 22 , electrodes  2210  may be coupled to amplification circuitry  2211  configured to amplify the biosignals conducted by electrodes  2210 . Amplification circuitry  2211  may include any suitable amplifier. Examples of suitable amplifiers may include operational amplifiers, differential amplifiers that amplify differences between two input voltages, instrumental amplifiers (e.g., differential amplifiers having input buffer amplifiers), single ended amplifiers, and/or any other suitable amplifier capable of amplifying biosignals. 
     As shown in  FIG. 22 , an output of amplification circuitry  2211  may be provided to analog-to-digital converter (ADC) circuitry  2214 , which may convert amplified biosignals to digital signals for further processing by a microprocessor  2216 . In some embodiments, microprocessor  2216  may process the digital signals to enhance remote or virtual social experiences (e.g., by converting or transforming the biosignals into an estimation of a spatial relationship of one or more skeletal structures in the body of user  2202  and/or a force exerted by at least one the skeletal structures in the body of user  2202 ). Microprocessor  2216  may be implemented by one or more hardware processors. In some embodiments, electrodes  2210 , amplification circuitry  2211 , ADC circuitry  2214 , and/or microprocessor  2216  may represent some or all of a single biosignal sensor. The processed signals output from microprocessor  2216  may be interpreted by a host machine  2220 , examples of which include, but are not limited to, a desktop computer, a laptop computer, a smartwatch, a smartphone, a head-mounted display device, or any other computing device. In some implementations, host machine  2220  may be configured to output one or more control signals for controlling a physical or virtual device or object based, at least in part, on an analysis of the signals output from microprocessor  2216 . As shown, biosignal sensing system  2200  may include additional sensors  2218 , which may be configured to record types of information about a state of a user other than biosignal information. For example, sensors  2218  may include, temperature sensors configured to measure skin/electrode temperature, inertial measurement unit (IMU) sensors configured to measure movement information such as rotation and acceleration, humidity sensors, and other bio-chemical sensors configured to provide information about the user and/or the user&#39;s environment. 
     As detailed above, the computing devices and systems described and/or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each include at least one memory device and at least one physical processor. 
     In some examples, the term “memory device” generally refers to any type or form of volatile or non-volatile storage device or medium capable of storing data and/or computer-readable instructions. In one example, a memory device may store, load, and/or maintain one or more of the modules described herein. Examples of memory devices include, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory. 
     In some examples, the term “physical processor” generally refers to any type or form of hardware-implemented processing unit capable of interpreting and/or executing computer-readable instructions. In one example, a physical processor may access and/or modify one or more modules stored in the above-described memory device. Examples of physical processors include, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor. 
     Although illustrated as separate elements, the modules described and/or illustrated herein may represent portions of a single module or application. In addition, in certain embodiments one or more of these modules may represent one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks. For example, one or more of the modules described and/or illustrated herein may represent modules stored and configured to run on one or more of the computing devices or systems described and/or illustrated herein. One or more of these modules may also represent all or portions of one or more special-purpose computers configured to perform one or more tasks. 
     In addition, one or more of the modules described herein may transform data, physical devices, and/or representations of physical devices from one form to another. For example, one or more of the modules recited herein may receive biosignals (e.g., biosignals containing eye-tracking data) to be transformed, transform the biosignals into a prediction of a user&#39;s intention to interact, output a result of the transformation to an intelligent-facilitation subsystem, and/or use the result of the transformation to suggest potential targets to the user and/or enable the user to select or interact with these suggested targets through a low-friction interaction. Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and/or any other portion of a physical computing device from one form to another by executing on the computing device, storing data on the computing device, and/or otherwise interacting with the computing device. 
     In some embodiments, the term “computer-readable medium” generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media include, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems. 
     The process parameters and sequence of the steps described and/or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and/or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various exemplary methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed. 
     The preceding description has been provided to enable others skilled in the art to best utilize various aspects of the exemplary embodiments disclosed herein. This exemplary description is not intended to be exhaustive or to be limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the present disclosure. The embodiments disclosed herein should be considered in all respects illustrative and not restrictive. Reference should be made to the appended claims and their equivalents in determining the scope of the present disclosure. 
     Unless otherwise noted, the terms “connected to” and “coupled to” (and their derivatives), as used in the specification and claims, are to be construed as permitting both direct and indirect (i.e., via other elements or components) connection. In addition, the terms “a” or “an,” as used in the specification and claims, are to be construed as meaning “at least one of.” Finally, for ease of use, the terms “including” and “having” (and their derivatives), as used in the specification and claims, are interchangeable with and have the same meaning as the word “comprising.”