# Patent

## Title
Optimization of a multi-view display

## Abstract

Described herein is a multi-view display (based on spatial and/or temporal multiplexing) having an optimization mechanism that dynamically adjust views based upon detected state changes with respect to one or more views. The optimization mechanism determines viewing parameters (e.g., brightness and/or colors) for a view based upon a current position of the view, and/or on the multi-view display's capabilities. The state change may correspond to the view (a viewer's eye) moving towards another viewing zone, in which event new viewing parameters are determined, which may be in anticipation of entering the zone. Another state change corresponds to more views being needed than the display is capable of outputting, whereby one or more existing views are degraded, e.g., from 3D to 2D and/or from a personal video to a non-personal view. Conversely, a state change corresponding to excess capacity becoming available can result in enhancing a view to 3D and/or personal.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
The present application is related to the copending U.S. patent application Ser. No. 12/819,238 entitled “Spatial and Temporal Multiplexing Display,” assigned to the assignee of the present application, filed concurrently herewith and hereby incorporated by reference.
BACKGROUND
A multi-view display allows different images to be seen from different points of view. This includes spatial multiplexing technology or directed backlight technology, in which lenses in front of light sources direct the light from illuminated pixels to different views.
In displays that use spatial multiplexing technology, increasing the number of views degrades the resolution of each view. In displays that use directed backlight technology, increasing the number of views reduces the frame rate for each view. Thus, one problem with a multi-view display is that the practical number of distinct views that can be output is limited by needing reasonable resolution to provide a decent image, or a fast enough frame rate to provide video without perceptible flicker. The number of views that may be needed may exceed that practical number of distinct views.
For example, a multi-view display capable of outputting eight views can show personal 2D video to eight people, or personal 3D video to four people (one view to each eye of each person, which directed backlighting can do without needing 3D glasses). However, if there are nine people watching a 2D video, or five watching a 3D video, the multi-view capabilities of the display device are exceeded. Moreover, the state of the views may change as people move between viewing zones, leave a room, or enter a room.
SUMMARY
This Summary is provided to introduce a selection of representative concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used in any way that would limit the scope of the claimed subject matter.
Briefly, various aspects of the subject matter described herein are directed towards a technology by which a multi-view display (based on spatial and/or temporal multiplexing) is configured with an optimization mechanism that dynamically adjust views based upon a detected state change, e.g., by an eye tracking component. In general, the optimization mechanism determines the viewing parameters for a view based upon a current position of the view, and/or on the capabilities of the multi-view display device.
In one aspect, the state change corresponds to the view (a viewer's eye) moving in one viewing zone towards another viewing zone. The optimization mechanism, which is associated with an anticipation algorithm, changes the viewing parameters (e.g., brightness and/or color values) according to an optimization model to new parameters for the other zone, in anticipation of the view moving into the other zone. In this manner, a changed view is generated for the new zone before the view moves into the new zone. In the event that another view is already in the other zone, the optimization model instead computes backed off parameters for the view and the other view.
In one aspect, the state change corresponds to a need for another new view that when combined with existing views exceeds the total view capabilities of the device. In response, the optimization mechanism changes the viewing parameters for the view by degrading the view, e.g., from a personal view to a non-personal view, and/or from a 3D view (e.g., the left-eye or right eye part) to a 2D view. In the event that excess capability becomes available with respect to generating the total number of views, the optimization mechanism may change the viewing parameters for the view by enhancing the view from a non-personal view to a personal view, and/or from a 2D view to a 3D view.
Other advantages may become apparent from the following detailed description when taken in conjunction with the drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which:
FIG. 1 is a block diagram representing a multiplexing system that optimizes views based upon view position and state changes with respect to the system.
FIG. 2 is a flow diagram representing example steps for optimizing a view based upon a state change in which the view moves towards and/or into another viewing zone.
FIG. 3 is a flow diagram representing example steps for optimizing views based on various input including a number of views desired.



DETAILED DESCRIPTION
Various aspects of the technology described herein are generally directed towards graceful optimization in a multi-view display that operates to smoothly adapt to state changes with respect to one or more views. As used herein, a “view” may refer to one eye of a person or the single eye of each of a set of multiple people, such as when displaying stereoscopic (3D) video; alternatively, a view may be the same to both of a person's eyes. Different views are generated by spatial multiplexing (lenticular arrays, lenslets), by temporal multiplexing (directed collimated backlight), or (as described in the aforementioned U.S. patent application entitled “Spatial and Temporal Multiplexing Display”) by a combination of spatial and temporal multiplexing.
Thus, the number of views and the output parameters to each view (e.g., frame rate, resolution) are dependent on the frame rate capabilities and spatial capabilities of the display device. As described herein, the views are optimized for a current state of the system's views. For example, views may be optimized based upon anticipation of a spatial (viewing zone) change due to a person's movement. An anticipated spatial change may result in computing modified display parameters (e.g., brightness, color and so forth) for the new perspective, so that the transition to a different viewing zone/angle is generally imperceptible. If two or more views that are otherwise independent views wind up in the same viewing zone due to one or more person's movement, (whereby independent views are not able to be displayed), the different views may be backed off (optimized for both viewers to some extent) in some way, such as smoothed together (e.g., averaged) to optimize a single, combined view for the multiple views.
Another aspect of optimization is when there are more views than the capabilities of the display can handle. In such an event, some or all of the current views are degraded to accommodate the extra view or views. When there is excess capacity, some or all of the current views may be enhanced relative to their previous configuration.
It should be understood that any of the examples herein are non-limiting. As such, the present invention is not limited to any particular embodiments, aspects, concepts, structures, functionalities or examples described herein. Rather, any of the embodiments, aspects, concepts, structures, functionalities or examples described herein are non-limiting, and the present invention may be used in various ways that provide benefits and advantages in computing and video technology in general.
FIG. 1 is a block diagram showing an example implementation that uses spatial or temporal multiplexing, or a combination of spatial and temporal multiplexing, to provide a plurality of (typically) differing views. The various components of FIG. 1 may be implemented in a computing environment external to a display, e.g., in a computer system or gaming console, for example, containing one or more processors and memory to perform spatial and temporal multiplexing. Alternatively, the components may be incorporated into a display device, such as a television set.
In the example of FIG. 1, an eye (head) tracking component 102 (e.g., using one or more cameras and software technology) provides an optimization mechanism (logic) 104 with the current number of views (eyes) and the position of each eye. Note that such head tracking technology already exists, based on known machine vision software technology, and is incorporated into gaming consoles, for example. Notwithstanding, any eye tracking technology may be used as described herein, including technology not yet developed.
Note that the video signals may be anything, such as a single video shot, a mix of different angles of the same 3D scene, a mix of different video shots (e.g., two television programs to distribute between different viewers) and so forth. Further note that if all views are of the same 3D scene but some (or all) views correspond to different viewing zones, the content (the viewing perspective) to show each view may be known based on the current position of that view.
As described herein, the optimization logic 104 determines how to distribute video signals 106 among the views. An optimization model 108 may be accessed by an anticipation algorithm 110 to prepare a new view if a viewer is entering into a new viewing zone, as described below. Preference rules and/or data 112 (which may be fixed defaults for a given display device) may be accessed to determine how to distribute resources and video to the views based on the device's spatial and/or temporal capabilities. For example, the preference rules/data 112 determines how to correlate more views than can be output given the spatial and frame rate capabilities of the device, or conversely, when less than all possible views are present, how to increase resolution and brightness, and/or to which view or views, and so forth. Note that the optimization logic 104 also may input (data corresponding to) the video signals, such as to determine whether the video is 2D or 3D, and also to possibly process content-related information or other video data in determining the distribution, e.g., to give a higher frame rate to people watching one video with a lot of motion, and less to those watching another video with little motion.
Based on how the resources and video are to be distributed among the views, the optimization logic 104 accesses the optimization model 108 for each view to determine optimal parameters for each view. The optimization model 108 may be based upon one or more cameras that provide a closed feedback loop, pre-calibration, theory, and/or experiments, and in general provides data such as brightness, color, chroma and so forth for each view. Note that the parameters may be per light source or may be for multiple light sources (e.g., global) to provide an optimal view according to the model for each view.
If only spatial multiplexing is available on the display device, then the parameters are simply output to spatial logic that divides the video and corresponding view parameters into subsets (e.g., vertical columns) of the pixels to provide the desired number of viewing zones. If temporal multiplexing is available, then a scheduling algorithm uses the parameters and eye positions to determine which light sources are illuminated when, and how, e.g., their brightness and color. Similar scheduling is used when both spatial and temporal multiplexing are available, as described in the aforementioned U.S. patent application. In this manner, the graphics hardware 116 drives the appropriate pixels of the multi-view display 118 to provide multiple views. This may include not illuminating pixels to available views where there is no viewer present, to save energy.
In one aspect, as a view is moving towards a new zone, the anticipation algorithm 110 (e.g., based upon or incorporating a Kalman filter) can prepare that view for the transition. For example, when a view is moving between spatial zones, the fine control of the directed backlight may be used to generate a new lensed view for the new zone (with parameters for the new viewing perspective), and once the person reaches the end of a lenticular zone, switch to the new lensed zone view. Using the optimization model 108 to determine new parameters, the switch may be made imperceptible to the eye.
FIG. 2 shows example logic for anticipating the change to a new (e.g., spatial) zone, beginning at step 202 which represents waiting for a view to be detected as moving to a new zone, e.g., based on the eye tracking position and known zone positions. Note that step 202 may be event driven (rather than looping back and waiting as illustrated for simplicity).
Step 204 represents the optimization logic 104 accessing the optimization model 108 to determine optimal parameters (e.g., brightness, color data and so forth) for the new zone. Note that even if the content being viewed is relatively static, the parameters may need to change because different lenses, distances and so forth apply to the new zone or directed backlight steered photons to the anticipated position.
Step 206 represents determining whether another view is already in that zone, as described below. If not, then the anticipated parameters for the view that were computed/determined may be output (step 208) to the next zone or position in advance. If the eye enters that zone, the view is already present with the appropriate parameters such that the transition is generally imperceptible. Note, however, that an alternative is to have former zone parameters, transition parameters and new zone parameters. For example, if a view is transitioning between zones, then the parameters (e.g., brightness/colors) of the former zone and the parameters of the new zone may be combined (e.g., via an appropriate function) according to the model 108 so that an eye corresponding to the view does not get too much brightness/improper colors just as the view crosses the zone dividing line.
Returning to step 206, it is possible that a view is entering a new zone that already has another, different view (or views) being shown. Consider for example that the right eye of person A enters a zone that person B is already within, viewing video frames. If directed backlight technology is unavailable to provide separate views within the spatial zone, or if the alignment is such that the right eye of person A is aligned with the left eye of person B and directed backlight is only able to collimate the light horizontally (not vertically), then a conflict exists.
Step 210 represents resolving the conflict by computing backed off parameters for the views, that is, the parameters are optimized for multiple views to some extent. For example, the parameters may be averaged or otherwise blended/smoothed for two or more views. This may work up to some number of different views, however if too many views are present, then the optimization logic 104 may instead degrade the device such that all the views in the zone are the same. For example, as described below, instead of personal 3D video where each person gets his or her own view based on their relative position to a scene, the optimization logic 104 may back off the views to non-personal 3D, or 2D for some or all of the viewers. The optimization logic 104 may choose to not show a view, such as if two different television programs corresponding to different views are being watched; the person entering the new view and causing the conflict may see nothing or may be switched to the view of the person that was already viewing in that zone.
As represented by steps 212 and 214, applying the backed off parameters may wait until the person actually enters the new zone. In this manner, for example, a person already in the zone does not receive a degraded view until necessary. However, some transitioning parameters/function may be applied to make the transition to the backed off parameters gradual, e.g., within the current zone at some approaching distance to the new zone, the backed off parameters are computed. As the distance gets closer, a transition function gradually adjusts the current zone parameter values (e.g., more towards the backed off parameter values) so that when the person does enter the zone and the backed off parameters are fully applied, the change is less perceptible to the existing viewer and/or the newly entering viewer.
Another aspect of optimization is directed towards correlating the spatial and/or temporal capabilities of the device with the number of views. For example, when the resolution capacity of a system is exceeded, the optimization logic 104 (e.g., in combination with the optimization model 108 and/or preference rules/data 112) needs to determine how to optimize the views.
By way of example, consider a desired offering of multiple personal 3D views, that is, a private or personal view may be a view that is visible to a person in one location and not visible to a person at another location. A 3D view may be a view that provides a different view to the left and right eye of a user to give the user a sense that the view is three dimensional. Even using the above described multi-view display, the capacity of the display device may be unable generate a sufficient number of (visually acceptable) personal 3D views for the number of viewers.
Various optimization options are available when the capacity is exceeded, generally comprising degrading one or more of the views to accommodate the number needed. Note that degradation may be dynamic, e.g., when a new viewer enters a room and starts looking at the display, the optimization logic 204 recognizes whenever the capacity is exceeded. For example, if the optimization logic 204 recognizes that the display device cannot support giving a personal 3D view to the new person, the display device may take a number of options, e.g., depending on the preference rules data 112 and what capacity is available. Further note that degradation may not be immediate, e.g., simply because a person is passing through a room and glances at the head tracking camera does not mean that existing viewers have their views degraded; degradation to accommodate the new person may be deferred until it is more certain that the new person is actually there to see the display.
By way of an example, the device may not have the capability to give the personal 3D view to the new person, but may have one view left via which the new person may receive a flat 2D picture. As a more particular example, if a display device is capable of outputting nine distinct views (e.g., three spatial times three temporal), four people may be receiving personal 3D video, thereby using eight of the nine possible views. The ninth view thus may be used to output 2D to the new person, as well to as any other person that enters later. For example, this may be accomplished by displaying 2D to all positions (zones and angles) except to those specific eye positions of the four personal 3D viewers.
Another option (when two views are available) is to provide non-personal 2D or 3D to one or more viewers, while other people get personal 3D or 2D. For example, consider that two views are available however two new people enter a room and look at the display. Each may receive personal 2D views (both of each person's eyes get the same view but each person gets a different view). Alternatively, non-personal 3D views may be presented.
If less than the number of views needed is available, one or more existing views need to be degraded as well. For example, if a large number of viewers enter a room, the system may degrade the views so that everyone gets a non-personal 2D view. As can be appreciated, various other techniques can also be used, e.g., degrade all but a privileged (view or views), degrade in time order (last person to start viewing is the first one degraded, and so forth). Other options include choosing the view based on the person/people sitting closest to the display, sitting closest to the center of the display, to the person who is talking the most or presently talking, to the person/people presently looking (e.g., based on gaze tracking), and so forth.
In contrast to degrading, enhancing the views relative to their previous state (e.g. 2D to 3D/non-personal to personal) is also possible, such as when one or more existing viewers leave the room, causing excess capacity. In general, the same alternatives exist for degradation as to which view (or views) is to be enhanced, and how each such view is to be enhanced.
FIG. 3 shows some example steps that may be performed by the optimization logic 204, beginning at step 302 where the number of eyes (maximum possible views desired) is received from the head tracking component. At step 304, the optimization logic 204 computes how many views are needed based upon the number of views and the 2D and/or 3D nature of the video signals 206.
As represented by step 306 and as described above, the preference rules/data 112 (and or the optimization model) 108 may be consulted to determine what to do when there is an inexact match between the views needed versus those that can be independently generated, e.g., which view or views are to be degraded (e.g., combined) or enhanced according to the preference data 208, given the current number of possible views. Content-based throttling or enhancement may also be performed, e.g., based on how the preference data specifies that current motion information be used, as also described above.
In general, via step 308 the scheduling algorithm 114 receives these computed/determined parameters from the optimization logic 104. For example, parameters may include an identifier for each view, and the type of output for that view, e.g., personal 3D, personal 2D, non-personal 3D or non-personal 2D. With this information and the position data for each distinct view, the scheduling algorithm 114 then determines the pixels to illuminate (including at what specific times for temporal multiplexing).
While the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.

## Claims

1. A system comprising:
a multi-view display device; and
logic configured to:
receive position data from at least one of an eye tracking component or a head tracking component, the position data indicating that a right eye view for a right eye of a first person that is located in a first viewing zone is moving toward a second viewing zone;
while the right eye view of the first person is in the first viewing zone and moving toward the second viewing zone:
determine right eye color or brightness parameters for the right eye view of the first person in the second viewing zone based at least in part upon the position data,
determine whether there is already a left eye view for a left eye of a second person in the second viewing zone,
and
in an instance when the left eye view of the second person is already in the second viewing zone, average, blend, or smooth the right eye color or brightness parameters for the right eye view of the first person with left eye color or brightness parameters for the left eye view of the second person to obtain output color or brightness parameters; and

control output of the multi-view display device using the output color or brightness parameters for the second viewing zone while the right eye view of the first person and the left eye view of the second person are concurrently in the second viewing zone.

2. The system of claim 1, wherein the logic is configured to control the output of the multi-view display device by controlling multiple light sources of the multi-view display device to transmit light having the output color or brightness parameters to the second viewing zone.

3. The system of claim 2, wherein the right eye color or brightness parameters, the left eye color or brightness parameters, and the output color or brightness parameters each comprise both brightness values and color values.

4. The system of claim 1, wherein the logic is configured to control the output of the multi-view display device to a plurality of other viewing zones while the right eye view of the first person and the left eye view of the second person are concurrently in the second viewing zone.

5. The system of claim 4, wherein the logic is configured to spatially multiplex a plurality of views to the plurality of viewing zones using vertical columns of pixels of the multi-view display device, the plurality of views including the right eye view of the first person and the left eye view of the second person.

6. The system of claim 5, wherein the logic is configured to temporally multiplex the plurality of views, including the right eye view of the first person and the left eye view of the second person, by selectively scheduling different light sources of the multi-view display device.

7. A system comprising:
a processing device; and
logic which, when executed by the processing device, causes the
processing device to:
receive position data indicating a position of a right eye view for a right eye of a first person that is in a first viewing zone and moving toward a second viewing zone, the right eye view of the first person having associated first brightness and color parameters for the right eye of the first person;
determine that there is a left eye view for a left eye of a second person that is already in the second viewing zone, the left eye view having associated second brightness and color parameters;
before the right eye view of the first person arrives in the second viewing zone with the left eye view of the second person, average, blend, or smooth the first brightness and color parameters with the second brightness and color parameters to obtain third brightness and color parameters;
wait until the right eye view of the first person enters the second viewing zone with the left eye view of the second person; and
upon detecting that the right eye view of the first person has entered the second viewing zone with the left eye view of the second person, using the third brightness and color parameters for both the right eye view of the first person and the left eye view of the second person.

8. The system of claim 7, wherein the logic further causes the processing device to:
generate a first three-dimensional view for the first person and a second three-dimensional view for the second person, the first three-dimensional view comprising the right eye view of the first person and a left eye view of the first person, the second three-dimensional view comprising the left eye view of the second person and a right eye view of the second person.

9. The system of claim 8, wherein the first three-dimensional view of the first person and the second three-dimensional view of the second person are different personal three-dimensional views.

10. The system of claim 9, wherein the logic further causes the processing device to:
detect one or more additional views of one or more additional people in the second viewing zone with the first three-dimensional view of the first person and the second three-dimensional view of the second person; and
change at least the first three-dimensional view of the first person to a non-personal three-dimensional view responsive to the one or more additional views of the one or more additional people being detected in the second viewing zone.

11. The system of claim 9, wherein the logic further causes the processing device to:
detect one or more additional views of one or more additional people in the second viewing zone with the first three-dimensional view of the first person and the second three-dimensional view of the second person; and
change at least the first three-dimensional view of the first person to a two-dimensional view responsive to the one or more additional views of the one or more additional people being detected in the second viewing zone.

12. The system of claim 8, wherein the logic further causes the processing device to:
select a view to degrade from the first three-dimensional view, the second three-dimensional view, and another view for another person, the selected view being selected for degrading based on gaze tracking of the first person, the second person, and the another person; and
degrade the selected view.

13. The system of claim 7, embodied as a display device, a gaming console, or a computing device that is not a display device and is not a gaming console.

14. A method of controlling a multi-view display device, the method comprising:
determining that a right eye view for a right eye of a first person is in a first viewing zone and moving toward a second viewing zone, the right eye view of the first person having associated first brightness or color parameters for the right eye of the first person;
determining that there is a left eye view that is already in the second viewing zone, the left eye view being for a left eye of a second person and having associated second brightness or color parameters;
before the right eye view of the first person arrives in the second viewing zone with the left eye view of the second person, averaging, blending, or smoothing the first brightness or color parameters with the second brightness or color parameters to obtain third brightness and color parameters;
detecting whether the right eye view of the first person has entered the second viewing zone with the left eye view of the second person; and
upon detecting that the right eye view of the first person has entered the second viewing zone with the left eye view of the second person, controlling the multi-view display device to use the third brightness or color parameters for the second viewing zone.

15. The method of claim 14, further comprising:
as the right eye view of the first person is moving toward the second viewing zone, computing transition brightness or color parameters for the right eye view of the first person and controlling the multi-view display device to use the transition brightness or color parameters while the right eye view of the first person is moving toward the second viewing zone.

16. The method of claim 15, further comprising using a Kalman filter to compute the transition brightness or color parameters.

17. The method of claim 14, wherein the third brightness or color parameters are obtained by averaging the first brightness or color parameters with the second brightness or color parameters.

18. The method of claim 14, wherein the third brightness or color parameters are obtained by blending the first brightness or color parameters with the second brightness or color parameters.

19. The method of claim 14, wherein the third brightness or color parameters are obtained by smoothing the first brightness or color parameters with the second brightness or color parameters.

20. The method of claim 14, performed by a processor of a computer system.