Patent Description:
Augmented Reality (AR) headsets include wearable eyeglasses that include an optical combiner that can act as transparent screens and are used to produce virtual images that are superimposed over a real-world background. <CIT> and <CIT> disclose examples of AR glasses.

Virtual Reality (VR) headsets include wearable viewing screens that block out vision of the real world and are used to create a view of a completely synthetic environment. <CIT>, invented by Hoellwarth discloses an example of a VR headset.

Mixed Reality (MR) can be thought of as a continuum of user interaction environments that range between a real environment and a totally virtual environment (Milgram & Colquhou, <NUM>). MR blends virtual worlds with the real world to produce new environments and visualizations where digital objects can appear to interact with the objects of the real world to various amounts, rather than just being passive within the real-world context.

<CIT> provides a system for determining the eye's focus of a user interacting with augmented reality where a focus mismatch between displayed object and detected eye's focus is corrected. A gaze tracker is used to monitor the line of sight of user's eyes and from the gaze the focal point is determined. When rendering the virtual object to be displayed for the user, not only the focal distance is considered, but also the vergence to compensate possible mismatches between the two eyes, which itself depends on the focus distance.

<CIT> suggests a method for adapting a virtual user interface close to a position where the user is looking to. The user interface is placed near a position corresponding to user's focal point and vergence. The focal point is derived from the two vergence angles <CIT> discloses displaying an image based on eye vergence. After fixation is observed, the disclosed eye vergence detection system detects a change in vergence determining that the eyes of the user are not focusing on the display location and providing, as response to this detection, the hiding of a portion of the images displayed.

The invention is defined in claims <NUM> and <NUM>, respectively.

The present invention provides a method for a person to exert control through eye vergence, the simultaneous movement of the pupils toward or away from one another during binocular fixating. This method can be used to exert control in real space as well as in virtual spaces. This method requires the presence of at least some hardware, including hardware capable of tracking both eyes, and hardware for analyzing the eye tracking output. Hardware is also necessary for implementing the intended control, whether by rendering a virtual reality differently in response to the eye vergence, or by similarly triggering actions in the real world such as dimming the room lights, changing a TV channel, or causing a robotic camera to take a picture. Hardware is described herein primarily in terms of head- mounted devices that incorporate all of the components necessary to track eye movement, head movement, to render virtual or digital images, and to implement other methods of the invention that detect eye vergence and act accordingly. It will be understood, however, that any, some, or all of these functions can be performed by hardware located off of the person's body.

An exemplary method comprises, or simply consists of or consists essentially of, the steps of fixating on an object and causing a response by eye vergence. In various embodiments the object is a real object or a virtual object, and in the latter embodiments the virtual object can exist in a virtual reality, augmented reality, or mixed reality. In various embodiments the response is a virtual response, that is, a response affecting the presentation of a virtual reality to the person, or a real response, that is, affecting the person's real world environment. Examples of virtual responses include translations and rotations of the virtual object, where the translations can be either towards or away from the person in addition to laterally. Another exemplary virtual response is to trigger new displays, such as new levels of a menu structure. Virtual responses include launching applications that manifest in the virtual reality, selecting virtual objects, tagging objects, playing sounds, acquiring a "screen shot," adjusting parametric data associated with the object, and so forth.

The following description is presented to enable persons skilled in the art to create and use the eye vergence controlled systems and methods described herein. Various modifications to the embodiments will be readily apparent to those skilled in the art. Moreover, in the following description, numerous details are set forth for the purpose of explanation. However, one of ordinary skill in the art will realize that the inventive subject matter might be practiced without the use of these specific details. In other instances, well known machine components, processes and data structures are shown in block diagram form in order not to obscure the disclosure with unnecessary detail. Identical reference numerals may be used to represent different views of the same item in different drawings. Flowcharts in drawings referenced below are used to represent processes. A hardware processor system may be configured to perform some of these processes. Modules within flow diagrams representing computer implemented processes represent the configuration of a processor system according to computer program code to perform the acts described with reference to these modules. Thus, the inventive subject matter is not intended to be limited to the embodiments shown, but is to be accorded the scope defined by the appended claims.

While methods of the present invention can be implemented in any of AR, MR, or VR, and will be described with reference to the AR and VR headsets discussed with reference to the following drawings that can be used to implement these methods. It will be understood that other systems or devices that are not worn on the user's head at all, or that locate some but not all components on the head, can also be used to generate virtual environments for the user. Thus, methods of the invention described herein are not limited to implementation by head-mounted devices and can also employ back-projected screens for stereoscopic presentations, for example. Finally, methods of the invention can be implemented in real-world contexts without implementing any of AR, MR, or VR.

<FIG> illustrates an exemplary AR headset embodiment <NUM> mounted on a head <NUM> of a user, also referred to herein as the person or viewer, to produce virtual or digital images that augment the user's view of the real world. The headset <NUM> includes means for securing the headset <NUM> to the user's head <NUM>, such as the arms of a pair of glasses, an adjustable headband, or a partial or full helmet, where such means are represented herein generally by mount <NUM>. The headset <NUM> also includes a transparent display screen <NUM> and a transparent protective visor <NUM>. In various embodiments the display screen <NUM> only appears transparent but is actually opaque and made to appear transparent by optical means. The display screen <NUM> and the protective visor <NUM> are both suspended from the mount <NUM> so as to be disposed in front of the viewer's eyes <NUM> with the display screen <NUM> positioned between the eyes <NUM> and the protective visor <NUM>. The protective visor <NUM> also may be disposed to provide optical power, such as in ordinary reading glasses, to produce the virtual images that the user views. The optical system itself may be customized to provide personalized optical corrections for user who normally need to use spectacles. The headset <NUM> further includes an eye tracking module <NUM> to monitor movements of both eyes <NUM> and a head tracking module <NUM> to monitor movement of the viewer's head <NUM>. Exemplary eye tracking modules <NUM> suitable for headset <NUM>, as well as eye tracking eyeglasses, are available from both SensoMotoric Instruments, Inc. of Boston, MA and Pupil Labs UG, of Berlin, Germany. Head tracking typically employs coils that pick up induced currents from constant or pulsed magnetic fields, or by camera-based processing of fixed active or passive fiducial markers on rigid bodies attached to the head <NUM>. A user's gaze direction in space is determined by first determining viewer's eye's gaze direction with respect to their head <NUM> and then adding it to their head's forward direction in space.

An image generation device <NUM>, consisting of a computer graphics system to calculate a geometric projection of synthetic environment and a physical visual display to present particular views of this environment, is configured to produce images <NUM> and 116R (<FIG>; shown together as ray <NUM> in <FIG>) on the display screen <NUM> that is perceived by the viewer as augmenting their view of the real world as seen through the display screen <NUM> and visor <NUM>. Image generation device <NUM> can include a processor to render the images <NUM> and 116R or the images <NUM>, 116R can be provided to the image generation device <NUM> from a processor <NUM> noted below.

A spatial sensor <NUM> detects physical objects and maps those objects so that, for example, virtual images can be correctly and accurately displayed in relation to the real-world objects. In some embodiments, the spatial sensor <NUM> includes an infrared (IR) detector, LIDAR, or a camera that detects markers on rigid bodies. In some embodiments, the spatial sensor <NUM> measures the distances from the headset <NUM> to the real-world objects, and as a user turns her head <NUM>, a map can be produced from the distance data, where the map includes three-dimensional geometric representations of objects in the environment. A suitable example of such mapping is simultaneous localization and mapping (SLAM) and can be performed either by a processor within the spatial sensor <NUM> or by a processor <NUM>, described below, in communication with the spatial sensor <NUM>.

Processor <NUM> is configured with instructions stored within a non-transitory storage device <NUM>. The processor <NUM> is in communication with other components such as eye tracking module <NUM>, head tracking module <NUM>, spatial sensor <NUM>, and image generation device <NUM> to work in conjunction with processing within these components or to provide the computation power these components lack.

In <FIG>, because of binocular presentation, the user perceives a virtual three-dimensional (3D) image <NUM>, which corresponds to the projected image <NUM> at a spatial location at distance AA from the eyes <NUM>. The virtual 3D image <NUM> is perceived as being disposed beyond the display screen <NUM>, such that the display screen <NUM> is seen as being disposed between the eye <NUM> and the virtual 3D image <NUM>. A virtual sight line <NUM> extends from each of the user's eyes <NUM>, through the display screen <NUM> and through the protective visor <NUM>, to the perceived location of the virtual 3D image <NUM>, which is perceived by the viewer to be at a distance AA from the eyes <NUM>.

The top view of <FIG> shows sight lines for the left and right eyes, <NUM> and 114R, that the user mentally combines to perceive the virtual 3D image <NUM> at the distance AA. The image generation device <NUM> produces a left real image <NUM> on a left portion <NUM> of the display screen <NUM> and a right real image 116R on a right portion 106R of the display screen <NUM>. In some embodiments, the image generation device <NUM> is embedded within the display screen <NUM> and includes optics to provide sufficient eye relief to allow comfortable viewing. In the illustrated embodiment, the image generation device projects the left and right real images <NUM>, 116R onto the display screen <NUM>. Thus, the user's left eye <NUM> receives a left eye view along the virtual left eye sight line <NUM> and the user's right eye 110R receives a right eye view along the right eye sight line 114R to perceive the virtual 3D image <NUM> at the distance AA.

<FIG> shows a second exemplary AR headset embodiment <NUM> mounted worn on the head <NUM> of a user to produce virtual images that augments the user's view of the real world. The headset <NUM> similarly includes a mount <NUM>, as described above, and a transparent protective visor <NUM>. The protective visor <NUM> is suspended from the mount <NUM> so as to be disposed in front of a user's eyes <NUM> and may act as a semitransparent mirror with optical power, as discussed. The headset <NUM> further includes a head tracking module <NUM>, an eye tracking module <NUM>, and a spatial sensor <NUM>, as generally described with respect to headset <NUM>. The headset <NUM> further includes an image generation device <NUM> that in these embodiments projects an image <NUM> onto the retina of each of the user's eyes <NUM> as indicated by an image projection ray <NUM>. More particularly, in some embodiments, the image generation device <NUM> projects the image onto an inside surface of the protective visor <NUM>, which reflects the projected image back to the user's eyes <NUM>. A processor <NUM> and non-transitory storage device <NUM> including instructions also comprise parts of the headset <NUM>.

The user perceives a virtual 3D image <NUM>, which corresponds to the projected image <NUM> at a spatial location and at a distance BB from the eyes <NUM>. The virtual 3D image <NUM> is disposed in front of the user's eyes <NUM> with the protective visor <NUM> disposed between the second virtual 3D image <NUM> and the user's eye <NUM>. A line of sight <NUM> extends from each of the user's eyes <NUM>, through the protective visor <NUM>, to the perceived virtual 3D image <NUM>, which is perceived by the user to be at a distance BB from the eyes <NUM>.

<FIG> is a top view of the headset <NUM> showing left and right sight lines <NUM> and 214R that the user mentally combines to perceive the virtual 3D image <NUM> as described with respect to the headset <NUM>.

<FIG> shows an exemplary embodiment of a VR headset <NUM> mounted on a head <NUM> of a user to produce interactive 3D virtual images. The third headset embodiment <NUM> includes a mount <NUM> and an opaque display screen <NUM>. In these embodiments either the mount <NUM>, or the mount <NUM> in combination with the display screen <NUM>, blocks the user's view of the real world either completely or substantially. The display screen <NUM> is attached to the mount <NUM> so as to be disposed in front of a user's eyes <NUM>.

The headset <NUM> further includes a head tracking module <NUM>, an eye tracking module <NUM>, and a spatial sensor <NUM>, as generally described with respect to headset <NUM>. The headset <NUM> further includes an image generation device <NUM> that produces an image <NUM> on the display screen <NUM>, for example, by any of the methods of the prior embodiments. A processor <NUM> and non-transitory storage device <NUM> including instructions also comprise parts of the headset <NUM>.

The user perceives a virtual 3D image <NUM>, which corresponds to the image <NUM> at a spatial location at distance CC from the eyes <NUM>. The virtual 3D image <NUM> is disposed in front of the user's eyes <NUM> with the display screen <NUM> disposed between the virtual 3D image <NUM> and the user's eyes <NUM>. A sight line <NUM> extends from each of the user's eyes <NUM>, through the display screen <NUM> to the perceived virtual 3D image <NUM>, which is perceived by the user to be at a distance CC from the eyes <NUM>.

<FIG> is a top view of the headset <NUM> showing left and right sight lines <NUM> and 314R that the user mentally combines to perceive the virtual 3D image <NUM> as described with respect to the headset <NUM>.

User control through tracking of eye vergence will now be described. The following embodiments describe methods that can be performed by a viewer to exert control through the use of eye movements, as well as methods of providing virtual realities, detecting eye movements, and varying the virtual reality in response to the eye movements. The methods of use do not necessarily require the viewer to wear a headset at all; in these embodiments eye tracking and head tracking, as well as image production, are all through external means. In some embodiments the viewer wears a headset with eye tracking and head tracking but the images are produced by means that are external to the headset. Various other combinations of headset-mounted and external components could also be employed so long as the user's eyes are tracked, and optionally the user's head is tracked and/or images are projected before the user's eyes. For instance, one camera on a cell phone can be configured to perform eye tracking, and the detection of eye vergence triggers the acquisition of a picture with the opposite-facing camera. Additionally, in addition to trigger responses, continuous and/or nondiscrete actions may be possible based on variable amounts of voluntary eye vergence.

Methods of the invention that provide virtual reality interfaces and track eye movement to allow a user to control the interface can be performed by headsets like headsets <NUM>-<NUM> as well as systems in which various or all components are external to the headset. For instance, the processor can be worn elsewhere on the body, or can be located off of the body but nearby, and either in Wi-Fi or wired communication with the headset. The computer instructions stored on the non-transitory memory device, whether as part of a headset or remote thereto, can include instructions necessary to direct the processor to perform the steps of these methods.

These methods, and the user methods, will first be illustrated with respect to a user controlling items like menu structures in a virtual environment. Generally, a system of the invention such as a headset produces a sense of virtual reality by reaction to a virtual environment which in one embodiment may be seen on a portion of a surface in front of the user where that virtual surface is at a distance from the user's eyes. The user accordingly perceives the virtual reality, separate from the real world, or integrated therewith with a gaze that fixates to the distance of the virtual surface. The user's head is tracked to maintain the virtual space, and the user's eyes are tracked to determine a change of fixation and to approximate the new fixation distance, sometimes denoted as z. The user can control menu structures, and achieve other controls, by aiming her head to direct her gaze in a particular orientation and by then refocusing her eyes appropriately such that her eye vergence serves to trigger a response. Eye vergence alone, or in combination with another signal such as a blink or a head nod, can trigger a response or control an object, virtual or real. These secondary signals can also be used to confirm a command made by eye vergence. While the first examples show menu structures, eye vergence can similarly be used to control virtual objects in the virtual reality to reposition, rotate, bring them forward, and push them away, or manipulate any other parameters such as color, associated data, etc..

It is further noted that the vergence detection can be "off-axis" such that the viewer's gaze line is not in line with her head's orientation, depending on the deflection of the eyes and/or depending on where the object is located within the field of view. Also, the eye gaze direction may be added to the head orientation on which the eyes rest, in some embodiments.

<FIG> shows an exemplary composite view of a sequence of four virtual 3D user interface display surfaces produced in accordance with some embodiments. These successive surfaces can represent different levels of a menu structure, for example. A first virtual display surface <NUM> is shown disposed at a first distance x<NUM> from a user's head <NUM>. A second virtual display surface <NUM> is shown disposed at a second distance x<NUM> from the user's head <NUM>. A third virtual display surface <NUM> is shown disposed at a third distance x<NUM> from the user's head <NUM>. A fourth virtual display surface <NUM> is shown disposed at a fourth distance x<NUM> from the user's head <NUM>. In this example, each closer display surface represents a successively deeper level of the menu structure.

In some embodiments, the distances at which successive virtual display surfaces are displayed are selected to simulate physical distances a user may encounter in the real world. For example, the distances can be selected to simulate a user searching for a book in a library. As a further example, the first virtual display surface <NUM> can be displayed at a 'searching' x<NUM> distance that is approximately eight times normal 'reading distance,' i.e., a distance that a person typically holds a book from their eyes when reading. The second virtual display surface <NUM> can be displayed at an 'approach' distance x<NUM> of four times the normal reading distance, the third virtual display surface <NUM> can be displayed at a 'reach-out' distance x<NUM> of twice the normal reading distance, while the fourth virtual display surface <NUM> can be displayed at the 'reading' distance x<NUM>, equal to the normal reading distance. Here, the virtual distances x<NUM> to x<NUM> are selected to simulate a user approaching a menu structure, where the objects in the closest display surface are perceived to be at a distance in the virtual environment where the user can grasp them. As described further below, the user moves through the several virtual display surfaces by adjusting eye fixation, and as one virtual display surface is selected and presented to the user, the prior one is removed or deemphasized, for instance, by being blurred, made increasingly transparent, or given reduced contrast.

The number of display surfaces, and the distances therebetween, are not limited by the preceding example. In various embodiments the distances can be varied dynamically. For example, these distances for a given menu structure can be varied in an AR or MR environment in response to the real-world component thereof. The same menu, when the user is in an open area can have wider spacings between virtual display surfaces then when the user is in a confined space, such as a bus seat. Mapping from a spatial sensor can be used to dynamically set such spacings.

In operation, the first virtual display surface <NUM> is initially displayed, being the highest level of the menu structure, and includes a plurality of selectable items A1-A8, each associated with an alternative next lower level of the menu structure. In some embodiments, associated with each item on the first virtual display surface <NUM> is a visual aid at a distance that is closer to the user than the item itself; the visual aid appears to the user to be in front of the associated item.

Visual aids provide virtual cues to the viewer to aid the process of eye vergence, but once a person acquires the skill, such cues typically become unnecessary. In various embodiments, the salience of the visual aid can be varied by making it blink or shimmer, larger or smaller, providing leading movement, or by varying its alpha, for example. Salience can be adjusted to make visual aids apparent without being distracting, and can become more or less salient as one's gaze approaches or moves away from the visual aids. In some instances, salience can be varied by the image generation device to lead the viewer to modify the dynamic properties of their eye vergence, such as to accelerate or decelerate eye vergence, creating a feedback that can be used, for example, to draw a virtual object closer or push it away. Here, rather than a trigger response, the system provides for continuous control. Visual aids can be represented as a visual ladder, in some instances, rather than a single spot, where the successive points of the ladder trigger differing actions and have different saliences.

In the example of <FIG>, the second virtual display surface <NUM> is displayed in response to the user selecting item Al by bringing her binocular fixation off of the first virtual display surface <NUM> and towards the visual aid associated with item A1, changing eye vergence. While eye vergence alone can be sufficient for some control actions, items can also be selected, or actions triggered or confirmed, by an additional blink, wink, nod, button press, spoken command, and so forth.

<FIG> shows a user navigating through an exemplary sequence of fixation points and a corresponding sequence of virtual display surfaces in accordance with some embodiments. <FIG> are perspective and side views, respectively, of a user whose head <NUM> is disposed at a first distance Y1A from a first virtual display surface S1 and a distance Y1B from a first fixation point FPIS11 associated with a first item IS<NUM> displayed on the first virtual display surface S1. The distance Y1A is a greater distance than Y1B, and therefore, the first fixation point FPIS11 is disposed in front of the first virtual display surface S1, relative to the position of the user's head <NUM>. In this embodiment the first virtual display surface S1, and the subsequent display surfaces, are spherically curved to indicate that from the perspective of the user, all points on the surface S1 are equidistant. It should be noted that projection onto a particularly spherical surface is not a requirement so long as an intercept between a gaze direction and the surface may be determined. It is also noted that the term "fixation point" is being used here in place of the terms "focal point" and "focus point" in the priority application.

An optional virtual visual aid B1 can be provided to the user in the form of a visual aid beam, or ray, or beam spot that shines on the surface S1 to indicate to the user where the user is looking, according to the head tracking module. The user can adjust her head position to direct the visual aid B1 to a selectable item on the surface S1. In the illustrative example in <FIG>, the visual aid B1 is directed at selectable item IS<NUM>. In accordance with some embodiments, to select item IS11, the user brings her fixation to the associated fixation point FPIS11, and optionally signals with an eye blink. An eye tracking module detects the change in user fixation and any blinking. In response to the signal while fixating on the fixation point FPIS11, a processor causes an image generation device to display a second virtual display surface S2A, as shown in <FIG>.

<FIG> show perspective and side views, respectively, of a viewer's head disposed at a distance Y1A from the first virtual display surface S1 and disposed at a second distance Y2A from a second virtual display surface S2A and at a distance Y2B from a second fixation point FPIS23 associated with a third selectable item IS23 displayed on the second virtual display surface S2A. The first virtual display surface S1 may continue to be displayed, although it can be deemphasized by being blurred or dimmed, for example. In the example in <FIG>, the virtual visual aid beam B1 is directed at item IS23. Moreover, the virtual visual aid B1 optionally can extend behind the second surface S2A to extend to item IS11. Thus, the visual aid beam B1 can illuminate the search path used to arrive at the second virtual display surface S2A. A third surface is selected in the same manner as above, as shown in <FIG>, and a fourth surface as shown in <FIG>.

Referring again to <FIG>, a back fixation point FB21 is shown for use to traverse backward from the second surface S2A to the first surface S1. From <FIG>, it can be seen that the back fixation point FB21 is disposed more distant from the user than is the second virtual display surface S2A. In accordance with some embodiments, the user can navigate back through the menu structure analogously to how the user navigates forward. In some embodiments, the second surface S2A disappears (not shown) upon selection of the first virtual display surface S1.

Table <NUM> is an exemplary information structure stored in a computer readable storage device for use to configure a processor, while the first virtual display surface is displayed, to control an image generation device to transition to a different virtual display surface in response to information received from a head tracker device and information received from an eye tracking module, in accordance with some embodiments.

Thus, for example, in accordance with the information structure of Table <NUM>, while the first virtual surface S1 is displayed, in response to detection of user head direction toward IS13 and user eyes fixating upon FPIS13 and blinking, virtual screen display S2c is displayed.

Table <NUM> is an example information structure stored in a computer readable storage device for use to configure a processor, while the second virtual display surface S2A is displayed, to control an image generation device to transition to a different virtual display surface in response to information received from a head tracker device and information received from an eye tracking module in accordance with some embodiments.

Persons skilled in the art will appreciated that in accordance with some embodiments, each virtual image, item, object, menu and so forth that is displayed to the viewer can be associated with a spatial location off of the active visual surface and some response that can be triggered, at least in part, by fixating upon that location.

<FIG> shows an exemplary graph <NUM> of the z-depth <NUM> of a user's eyes as they fixate from a near object to a far object to one in between. The z-depth <NUM> remains fairly constant while fixation remains on any object, then shifts quickly to the next. A simplistic means of detecting the vergence of the viewer's eyes that is sufficient to trigger a response includes monitoring the z-depth for a change by more than a threshold distance. Thus, the change from one average z-depth <NUM> to another beyond a threshold could be a trigger. A first derivative of the z-depth <NUM> as a function of time is approximately zero while the viewer fixates on each object, and either spikes positive or negative when the eyes converge or diverge. In the invention, the first derivative, if it exceeds a threshold, or indeed any computable dynamic characteristic of motion, is used as a trigger. Similarly, one can sample z-depth <NUM> with a given frequency and create a rolling average of n number of samples, and then monitor the difference between two such rolling averages, where the two are offset in time by some number of samples. Such an example is illustrated by lines <NUM> and <NUM>, and although they are best fits to the curve, one can see how an average of the z-depth values will change, as will the difference between them. Thus, another trigger can be that the difference between two rolling averages exceeds a threshold. In further embodiments, the z-depth data is processed, such as by smoothing, before being analyzed to detect eye vergence. Data processing of the z-depth data can include applying windowing functions. Further, median values can be used in place of averages. In still further embodiments a second derivative of the z-depth data is determined and can be used to vary salience values of visual aids, for example.

<FIG> is a flowchart representation of an exemplary method <NUM> of the present invention for providing control to a user. The method <NUM> begins with a step <NUM> of storing an association between an object and a response in a non-transitory storage device. The object can be real, such as a lamp, or an item shown in a 2D display such as an advertisement displayed on a cell phone, or can be a virtual object in a virtual reality or in an augmented or mixed reality. Storing the association allows the response to be retrieved as needed when a selection implicates the object.

An optional next step <NUM> comprises providing a digital image. The step is optional in as much as embodiments of the present invention do not require the creation of virtual objects but can operate on real objects as well. In a further optional step <NUM> a visual aid is provided in the viewer's field of view and proximate to the object. Where the object is a real object, headsets like those described above, as well as other systems, can be used to display visual aids to the viewer even in the absence of any other digital image content.

In an optional step <NUM>, an eye tracking module is used to detect binocular fixation of the user's eyes upon the object. This step is also optional in as much as in some instances one could look in the direction of an object without actually fixating on it. Detecting binocular fixation upon the object can include determining that the binocular fixation of the eyes is within a threshold distance of the object. In a step <NUM>, vergence of viewer's eyes is detected, again using the eye tracking module. In both steps, monitoring the z-depth of the binocular fixation of the eyes can be employed. Step <NUM> can optionally include receiving a confirmation signal from the viewer.

In a step <NUM> the response is provided. The response can be either discrete or not. In those embodiments in which the response is not discrete, for example, the response can be continuous with a feedback loop between steps <NUM> and <NUM> such that the response is dependent upon continuous monitoring of eye vergence.

<FIG> illustrate another virtual display surface embodiment of the invention. <FIG> shows a virtual display surface comprising multiple intersecting virtual spheres <NUM>-<NUM>, each corresponding to a different dataset. In the illustrated example, the spheres are labeled to indicate the types of data they are associated with, e.g., work, sports, holiday. To select a dataset, in some embodiments, the user directs her gaze at a sphere of the surface and draws her gaze towards her, possibly assisted by a visual aid seen proximate to the sphere. In some instances the selection is confirmed by a signal like a wink or head nod. In response, a processor causes an image generation device to produce a new virtual image such as the virtual enlarged sphere shown in <FIG> with numerous image tiles posted on it.

Claim 1:
A system for providing control to a user perceiving a virtual reality with a gaze that fixates to the distance of an object, the system comprising:
a non-transitory storage device (<NUM>) storing an association between the object and a response;
an eye tracking module (<NUM>) configured to determine lines (<NUM>) of sight for both of the user's eyes; and
a processor (<NUM>) configured
to receive the lines (<NUM>) of sight and determine both the user's gaze therefrom and to measure the viewer's eye vergence, wherein the vergence is the simultaneous movement of the user's pupils toward or away from one another during change of binocular fixating,
to detect the binocular fixation upon the object,
then to detect the vergence with the eye tracking module (<NUM>) including to monitor the z-depth of the binocular fixation of the eyes and to determine that a first derivative of the z-depth has changed by more than a threshold amount, and
to provide the response in dependency of the detected eye vergence.