Patent Publication Number: US-9900694-B1

Title: Speaker array for sound imaging

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of and claims priority from U.S. patent application Ser. No. 13/534,978, entitled “Speaker Array for Sound Imaging,” filed Jun. 27, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Augmented reality allows interaction among users, real-world objects, and virtual or computer-generated objects and information within an environment. The environment may be, for example, a room equipped with computerized projection and imaging systems that enable presentation of images on various objects within the room and facilitate user interaction with the images and/or objects. The augmented reality may range in sophistication from partial augmentation, such as projecting a single image onto a surface and monitoring user interaction with the image, to full augmentation where an entire room is transformed into another reality for the user&#39;s senses. The user can interact with the environment in many ways, including through motion, gestures, voice, and so forth. 
     One of the challenges associated with augmented reality is creation of high quality sound within the environment. This is particularly the case when certain objects and/or users are moving about within the environment. There is a continuing need for improved systems that create a richer audio experience for the user, even in environments with moving objects and/or people. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical components or features. 
         FIG. 1  shows an illustrative scene with an augmented reality environment hosted in an environmental area, such as a room. The augmented reality environment is provided, in part, by three projection and image capture systems. Additionally, a sound system with a spherical speaker array is provided centrally in the room to provide an enriched audio experience throughout the environment. 
         FIG. 2  shows a projection and image capturing system formed as an augmented reality functional node having a chassis to hold a projector and camera in spaced relation to one another. 
         FIG. 3  illustrates one example implementation of creating an augmented reality environment by projecting a structured light pattern on a scene and capturing a corresponding image of the scene. 
         FIG. 4  shows a fixed speaker array and controller for creating a rich sound experience from a single location within the room of  FIG. 1 . 
         FIG. 5  shows an illustrative process of providing rich audio output within an enhanced augmented reality environment using a fixed location speaker array. 
     
    
    
     DETAILED DESCRIPTION 
     Augmented reality environments allow users to interact with physical and virtual objects in a physical space. Augmented reality environments are formed through systems of resources such as cameras, projectors, computing devices with processing and memory capabilities, and so forth. The projectors project images onto the surroundings that define the environment and the cameras monitor and capture user interactions with such images. 
     An augmented reality environment is commonly hosted or otherwise set within a surrounding area, such as a room, building, or other type of space. In some cases, the augmented reality environment may involve the entire surrounding area. In other cases, an augmented reality environment may involve a localized area of a room, such as a reading area or entertainment area. 
     Described herein is an architecture to create an augmented reality environment and to generate a rich audio experience within the environment from a fixed location speaker array. The architecture may be implemented in many ways. One illustrative implementation is described below in which an augmented reality environment is created within a room. The architecture includes one or more projection and camera systems, as well as a centrally mounted speaker array. The various implementations of the architecture described herein are merely representative. 
     Illustrative Environment 
       FIG. 1  shows an illustrative augmented reality environment  100  created within a scene, formed within an environmental area, such as a room. Three augmented reality functional nodes (ARFN)  102 ( 1 )-( 3 ) are shown within the room. Each ARFN contains projectors, cameras, and computing resources that are used to generate the augmented reality environment  100 . In this illustration, the first ARFN  102 ( 1 ) is a fixed mount system that may be mounted within the room, such as to the ceiling, although other placements are possible. The first ARFN  102 ( 1 ) projects images onto the scene, such as onto a surface or screen  104  on a wall of the room. A first user  106  may watch and interact with the images being projected onto the wall, and the ceiling-mounted ARFN  102 ( 1 ) may capture that interaction. One implementation of the first ARFN  102 ( 1 ) is provided below in more detail with reference to  FIG. 2 . 
     A second ARFN  102 ( 2 ) is embodied as a table lamp, which is shown sitting on a desk  108 . The second ARFN  102 ( 2 ) projects images  110  onto the surface of the desk  108  for the user  106  to consume and interact. The projected images  110  may be of any number of things, such as homework, video games, news, or recipes. 
     A third ARFN  102 ( 3 ) is also embodied as a table lamp, shown sitting on a small table  112  next to a chair. A second user  114  is seated in the chair and is holding a portable projection screen  116 . The third ARFN  102 ( 3 ) projects images onto the surface of the portable screen  116  for the user  114  to consume and interact. The projected images may be of any number of things, such as books, games (e.g., crosswords, puzzles, etc.), news, magazines, movies, browser, etc. The portable screen  116  may be essentially any device for use within an augmented reality environment, and may be provided in several form factors. It may range from an entirely passive, non-electronic, mechanical surface to a full functioning, full processing, electronic device with a projection surface. 
     These are just sample locations. In other implementations, one or more ARFNs may be placed around the room in any number of arrangements, such as on in furniture, on the wall, beneath a table, and so forth. 
     Each of the ARFNs  102 ( 1 )-( 3 ) may be equipped with one or more microphones to capture audio sound within the environment as well as with one or more speakers to output sound into the environment. Additionally or alternatively, the architecture includes a standalone speaker array  118  mounted centrally of the room. In this example, the speaker array  118  is mounted to the ceiling in a fixed location at approximately the center of the room. However, other locations are possible. 
     The speaker array  118  is configured to provide full spectrum, high fidelity sound within the environment  100 . The speaker array  118  is illustrated as a sphere with multiple speakers mounted thereon to output sound in essentially any direction. The multiple speakers may be individually controlled to form directional beams that may be essentially “aimed” in any number of directions. Beam shaping relies on various techniques, such as time delays between applying the audio signal to two or more different speakers. 
     In  FIG. 1 , multiple beams are shown emanating from the speaker array  118 . A first beam  120  is directed at the user  106  to provide primary channel sound to the user who is watching a program on the screen or surface  104 . A second beam  122  is directed to the wall that contains the screen or surface  104 , where the sound is reflected back toward the user  106 . This reflected sound may carry, for example, background audio components, such as that used in surround sound. The beams are timed such that the primary beam  120  reaches the user  106  at a suitable time in coordination with the reflected beam  122  providing stereo and surround sound characteristics. These first two beams  120  and  122  thereby provide a rich audio experience for the user  106  who is watching the video program being projected onto the screen  104 . 
     Concurrent with the first two beams  120  and  122 , a third beam  124  is shown directionally output toward the user  114  seated in the chair. Suppose that the seated user  114  is listening to an audio book or to music while reading an electronic book projected onto the screen  116 . The third beam  124  carries this separate audio to the user  114  to provide an enhanced audio experience, while the other two beams  120  and  122  continue to provide rich sound entertainment to the standing user  106  in the room. 
     Associated with each ARFN  102 ( 1 )-( 3 ), or with a collection of ARFNs, is a computing device  130 , which may be located within the augmented reality environment  100  or disposed at another location external to it. Each ARFN  102  may be connected to the computing device  130  via a wired network, a wireless network, or a combination of the two. The computing device  130  has a processor  132 , an input/output interface  134 , and a memory  136 . The processor  132  may include one or more processors configured to execute instructions. The instructions may be stored in memory  136 , or in other memory accessible to the processor  132 , such as storage in cloud-based resources. 
     The input/output interface  134  may be configured to couple the computing device  130  to other components, such as projectors, cameras, microphones, other ARFNs, other computing devices, and so forth. The input/output interface  134  may further include a network interface  138  that facilitates connection to a remote computing system, such as cloud computing resources. The network interface  138  enables access to one or more network types, including wired and wireless networks. More generally, the coupling between the computing device  130  and any components may be via wired technologies (e.g., wires, fiber optic cable, etc.), wireless technologies (e.g., RF, cellular, satellite, Bluetooth, etc.), or other connection technologies. 
     The memory  136  may include computer-readable storage media (“CRSM”). The CRSM may be any available physical media accessible by a computing device to implement the instructions stored thereon. CRSM may include, but is not limited to, random access memory (“RAM”), read-only memory (“ROM”), electrically erasable programmable read-only memory (“EEPROM”), flash memory or other memory technology, compact disk read-only memory (“CD-ROM”), digital versatile disks (“DVD”) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computing device. 
     Several modules such as instructions, datastores, and so forth may be stored within the memory  136  and configured to execute on a processor, such as the processor  132 . An operating system module  140  is configured to manage hardware and services within and coupled to the computing device  130  for the benefit of other modules. 
     A spatial analysis module  142  is configured to perform several functions which may include analyzing a scene to generate a topology, recognizing objects in the scene, and dimensioning the objects and physical boundaries (e.g., walls, ceiling, floor, etc.) of the scene. From this, the spatial analysis module  142  creates a 3D model  144  of the scene. The 3D scene model  144  contains an inventory of objects within the scene, the various physical boundaries (e.g., walls, floors, ceiling, etc.), the numerous surfaces provided by the objects and physical boundaries, and dimensions of the rooms. Characterization of the scene may be facilitated using several technologies including structured light, light detection and ranging (LIDAR), optical time-of-flight, ultrasonic ranging, stereoscopic imaging, radar, and so forth either alone or in combination with one another. For convenience, and not by way of limitation, some of the examples in this disclosure refer to structured light although other techniques may be used. The spatial analysis module  142  provides the information used within the augmented reality environment to provide an interface between the physicality of the scene and virtual objects and information. 
     A system parameters datastore  146  is configured to maintain information about the state of the computing device  130 , the input/output devices of the ARFN, and so forth. For example, system parameters may include current pan and tilt settings of the cameras and projectors. As used in this disclosure, the datastore includes lists, arrays, databases, and other data structures used to provide storage and retrieval of data. 
     An object parameters datastore  148  in the memory  136  is configured to maintain information about the state of objects within the scene. The object parameters may include the surface contour of the object, overall reflectivity, color, and so forth. This information may be acquired from the ARFN, other input devices, or via manual input and stored within the object parameters datastore  148 . 
     An object datastore  150  is configured to maintain a library of pre-loaded reference objects. This information may include assumptions about the object, dimensions, and so forth. For example, the object datastore  150  may include a reference object of a beverage can and include the assumptions that beverage cans are either held by a user or sit on a surface, and are not present on walls or ceilings. The spatial analysis module  142  may use this data maintained in the object datastore  150  to test dimensional assumptions when determining the dimensions of objects within the scene. In some implementations, the object parameters in the object parameters datastore  148  may be incorporated into the object datastore  150 . For example, objects in the scene which are temporally persistent, such as walls, a particular table, particular users, and so forth may be stored within the object datastore  150 . The object datastore  150  may be stored on one or more of the memory of the ARFN, storage devices accessible on the local network, or cloud storage accessible via a wide area network. 
     A user identification and authentication module  152  is stored in memory  136  and executed on the processor(s)  132  to use one or more techniques to verify users within the environment  100 . In one implementation, the ARFN  102 ( 1 ) may capture an image of the user&#39;s face and the spatial analysis module  142  reconstructs 3D representations of the user&#39;s face. Rather than 3D representations, other biometric profiles may be computed, such as a face profile that includes key biometric parameters such as distance between eyes, location of nose relative to eyes, etc. In such profiles, less data is used than full reconstructed 3D images. The user identification and authentication module  140  can then match the reconstructed images (or other biometric parameters) against a database of images (or parameters), which may be stored locally or remotely on a storage system or in the cloud, for purposes of authenticating the user. If a match is detected, the user is permitted to interact with the system. 
     An augmented reality module  154  is configured to generate augmented reality output in concert with the physical environment. The augmented reality module  154  may employ essentially any surface, object, or device within the environment  100  to interact with the users. The augmented reality module  154  may be used to track items within the environment that were previously identified by the spatial analysis module  142 . The augmented reality module  154  includes a tracking and control module  156  configured to track one or more items within the scene and accept inputs from or relating to the items. For instance, the tracking and control module  156  may track portable screens, such as screen  116 , so that images are accurately projected onto the movable item. Additionally, the tracking and control module  156  may be used to track other objects as well as the users  106  and  114  within the scene. As the users move about the room or as objects are moved about the room, the tracking and control module  156  tracks the movement and feeds this information to other components within the ARFN  102 ( 1 ) to determine whether to change any aspects of the augmented reality environment, including the audio output of the speaker array  118 . 
     A speaker array controller  158  is shown stored in the memory  136  for execution on the processor(s)  132 . Alternatively, it may be implemented as a hardware or firmware component. The speaker array controller  158  controls the speaker array  118  to output sound in directional beams that can be targeted to specific locations that enhance user experience. The directionality is determined based on any number of sound goals, which might include, for example, high precision sound localization (e.g., for the seated user  114 ) and/or full spectrum, surround sound (e.g., for the standing user  106 ). The speaker array controller  158  has a beam shaper  160  to shape audio beams output by a single speaker or sets of speakers within the array  118 . The beam shaper  160  chooses which speakers in the array should be used to construct the directional sound beams. The sound beams are essentially sound produced by the speakers that, when output, is more perceptible at certain locations than other locations. Examples of this process are shown and described with reference to  FIG. 4 . 
     The ARFNs  102 ( 1 )-( 3 ) and computing components of device  130  that have been described thus far may be operated to create an augmented reality environment in which images are projected onto various surfaces and items in the room, and the users  106  and  114  may interact with the images. The users&#39; movements, voice commands, and other interactions are captured by the ARFNs cameras to facilitate user input to the environment. 
     Example ARFN Implementation 
       FIG. 2  shows an illustrative schematic  200  of the first augmented reality functional node  102 ( 1 ) and selected components. The first ARFN  102 ( 1 ) is configured to scan at least a portion of a scene  202  and the objects therein. The ARFN  102 ( 1 ) may also be configured to provide augmented reality output, such as images, sounds, and so forth. 
     A chassis  204  holds the components of the ARFN  102 ( 1 ). Within the chassis  204  may be disposed a projector  206  that generates and projects images into the scene  202 . These images may be visible light images perceptible to the user, visible light images imperceptible to the user, images with non-visible light, or a combination thereof. This projector  206  may be implemented with any number of technologies capable of generating an image and projecting that image onto a surface within the environment. Suitable technologies include a digital micromirror device (DMD), liquid crystal on silicon display (LCOS), liquid crystal display, 3LCD, and so forth. The projector  206  has a projector field of view  208  which describes a particular solid angle. The projector field of view  208  may vary according to changes in the configuration of the projector. For example, the projector field of view  208  may narrow upon application of an optical zoom to the projector. In some implementations, a plurality of projectors  206  may be used. Further, in some implementations, the projector  206  may be further configured to project patterns, such as non-visible infrared patterns, that can be detected by camera(s) and used for 3D reconstruction and modeling of the environment. The projector  206  may comprise a microlaser projector, a digital light projector (DLP), cathode ray tube (CRT) projector, liquid crystal display (LCD) projector, light emitting diode (LED) projector or the like. 
     A camera  210  may also be disposed within the chassis  204 . The camera  210  is configured to image the scene in visible light wavelengths, non-visible light wavelengths, or both. The camera  210  may be implemented in several ways. In some instances, the camera may be embodied an RGB camera. In other instances, the camera may include ToF sensors. In still other instances, the camera  210  may be an RGBZ camera that includes both ToF and RGB sensors. The camera  210  has a camera field of view  212  which describes a particular solid angle. The camera field of view  212  may vary according to changes in the configuration of the camera  210 . For example, an optical zoom of the camera may narrow the camera field of view  212 . In some implementations, a plurality of cameras  210  may be used. 
     The chassis  204  may be mounted with a fixed orientation, or be coupled via an actuator to a fixture such that the chassis  204  may move. Actuators may include piezoelectric actuators, motors, linear actuators, and other devices configured to displace or move the chassis  204  or components therein such as the projector  206  and/or the camera  210 . For example, in one implementation, the actuator may comprise a pan motor  214 , tilt motor  216 , and so forth. The pan motor  214  is configured to rotate the chassis  204  in a yawing motion. The tilt motor  216  is configured to change the pitch of the chassis  204 . By panning and/or tilting the chassis  204 , different views of the scene may be acquired. The spatial analysis module  142  may use the different views to monitor objects within the environment. 
     One or more microphones  218  may be disposed within the chassis  204 , or elsewhere within the scene. These microphones  218  may be used to acquire input from the user, for echolocation, location determination of a sound, or to otherwise aid in the characterization of and receipt of input from the scene. For example, the user may make a particular noise, such as a tap on a wall or snap of the fingers, which are pre-designated to initiate an augmented reality function. The user may alternatively use voice commands. Such audio inputs may be located within the scene using time-of-arrival differences among the microphones and used to summon an active zone within the augmented reality environment. Further, the microphones  218  may be used to receive voice input from the user for purposes of identifying and authenticating the user. The voice input may be received and passed to the user identification and authentication module  152  in the computing device  130  for analysis and verification. 
     One or more speakers  220  may also be present to provide for audible output. For example, the speakers  220  may be used to provide output from a text-to-speech module, to playback pre-recorded audio, etc. 
     A transducer  222  may be present within the ARFN  102 ( 1 ), or elsewhere within the environment, and configured to detect and/or generate inaudible signals, such as infrasound or ultrasound. The transducer may also employ visible or non-visible light to facilitate communication. These inaudible signals may be used to provide for signaling between accessory devices and the ARFN  102 ( 1 ). 
     A ranging system  224  may also be provided in the ARFN  102  to provide distance information from the ARFN  102  to an object or set of objects. The ranging system  224  may comprise radar, light detection and ranging (LIDAR), ultrasonic ranging, stereoscopic ranging, and so forth. In some implementations, the transducer  222 , the microphones  218 , the speaker  220 , or a combination thereof may be configured to use echolocation or echo-ranging to determine distance and spatial characteristics. 
     A wireless power transmitter  226  may also be present in the ARFN  102 ( 1 ), or elsewhere within the augmented reality environment. The wireless power transmitter  226  is configured to transmit electromagnetic fields suitable for recovery by a wireless power receiver and conversion into electrical power for use by active components in other electronics, such as a non-passive screen  116 . The wireless power transmitter  226  may also be configured to transmit visible or non-visible light to communicate power. The wireless power transmitter  226  may utilize inductive coupling, resonant coupling, capacitive coupling, and so forth. 
     In this illustration, the computing device  130  is shown within the chassis  204 . However, in other implementations all or a portion of the computing device  130  may be disposed in another location and coupled to the ARFN  102 ( 1 ). This coupling may occur via wire, fiber optic cable, wirelessly, or a combination thereof. Furthermore, additional resources external to the ARFN  102 ( 1 ) may be accessed, such as resources in another ARFN accessible via a local area network, cloud resources accessible via a wide area network connection, or a combination thereof. 
     The ARFN  102 ( 1 ) is characterized in part by the offset between the projector  206  and the camera  210 , as designated by a projector/camera linear offset “O”. This offset is the linear distance between the projector  206  and the camera  210 . Placement of the projector  206  and the camera  210  at distance “O” from one another aids in the recovery of structured light data from the scene. The known projector/camera linear offset “O” may also be used to calculate distances, dimensioning, and otherwise aid in the characterization of objects within the scene  202 . In other implementations, the relative angle and size of the projector field of view  208  and camera field of view  212  may vary. Also, the angle of the projector  206  and the camera  210  relative to the chassis  204  may vary. 
       FIG. 3  illustrates one example operation  300  of the ARFN  102 ( 1 ) of creating an augmented reality environment by projecting a structured light pattern on a scene and capturing a corresponding image of the scene. In this illustration, the projector  206  within the ARFN  102 ( 1 ) projects a structured light pattern  302  onto the scene  202 . In some implementations, a sequence of different structure light patterns  302  may be used. This structured light pattern  302  may be in wavelengths which are visible to the user, non-visible to the user, or a combination thereof. The structured light pattern  304  is shown as a grid in this example, but not by way of limitation. In other implementations, other patterns may be used, such as bars, dots, pseudorandom noise, and so forth. Pseudorandom noise (PN) patterns are particularly useful because a particular point within the PN pattern may be specifically identified. A PN function is deterministic in that given a specific set of variables, a particular output is defined. This deterministic behavior allows the specific identification and placement of a point or block of pixels within the PN pattern. 
     The user  106  is shown within the scene  202  such that the user&#39;s face  304  is between the projector  206  and a wall. A shadow  306  from the user&#39;s body appears on the wall. Further, a deformation effect  308  is produced on the shape of the user&#39;s face  304  as the structured light pattern  302  interacts with the facial features. This deformation effect  308  is detected by the camera  210 , which is further configured to sense or detect the structured light. In some implementations, the camera  210  may also sense or detect wavelengths other than those used for structured light pattern  302 . 
     The images captured by the camera  210  may be used for any number of things. For instances, some images of the scene are processed by the spatial analysis module  132  to characterize the scene  202 . In some implementations, multiple cameras may be used to acquire the image. In other instances, the images of the user&#39;s face  304  (or other body contours, such as hand shape) may be processed by the spatial analysis module  132  to reconstruct 3D images of the user, which are then passed to the user identification and authentication module  140  for purposes of verifying the user. 
     Certain features of objects within the scene  202  may not be readily determined based upon the geometry of the ARFN  102 ( 1 ), shape of the objects, distance between the ARFN  102 ( 1 ) and the objects, and so forth. As a result, the spatial analysis module  132  may be configured to make one or more assumptions about the scene, and test those assumptions to constrain the dimensions of the scene  202  and maintain the model of the scene. 
     Illustrative Speaker Array and Controller 
       FIG. 4  shows a sound system  400  having the fixed speaker array  118  and the speaker array controller  158  for creating a rich sound experience from a single location within the room of  FIG. 1 . The speaker array  118  includes a spherical body  402  attached to a base mount  404 . The base mount  404  may be used to secure the speaker array  118  to a fixed and central location within the environment, such as the middle point of a room ceiling as shown in  FIG. 1 . As an alternative to the spherical shape, the body  402  may be implemented has a hemisphere or other physical shapes, such as a cone, cylinder, or any other shape that allows for omni-directional emission of sound. 
     The speaker array  118  houses and positions multiple speakers  406 ( 1 ),  406 ( 2 ), . . . ,  406 (S). The speakers  406 ( 1 )-(S) may be arranged symmetrically about the sphere, spaced equidistant apart from one another. Moreover, the speakers  406 ( 1 )-(S) may be oriented outward along radii of the spherical or hemispherical body  402 . However, other arrangements of the speakers about the spherical or hemispherical body  402  may be used. 
     The speaker array controller  158  is provided to control the individual speakers  406 ( 1 )-(S) in the array  118 . The speaker array controller  158  receives the 3D scene model  144  from the spatial analysis module  142  to understand the dimensions of the room, permanent structures, objects therein, and so forth. The speaker array controller  158  may also receive data pertaining to the screen/object location(s)  408  and user location(s)  410  from the tracking and control  156 . These locations help the speaker array controller  158  determine various targets for sound output. 
     A sound target module  412  receives the 3D scene model  144 , the screen/object location(s)  408 , and the user location(s)  410  and based on this information, determines possible regions for sound localization or directive output. Shown in  FIG. 4 , suppose the user  106  is positioned beside a right side wall  414 , but facing leftward to look across the room. For instance, the user may be watching a movie being projected on an opposing wall across the room, similar to that shown in  FIG. 1 . In this situation, the 3D scene model  144  provides dimension data, such as a distance from the speaker array  118  to the wall  414 , to the sound target module  412 . It is noted that the 3D scene model  144  may be created automatically, such as by the spatial analysis module  142 . Alternatively, 3D scene model  144  may be captured by measuring the physical layout of the room and cataloging the objects in the room. The tracking and control module  156  provides updated location information for any objects moving about the scene or when the user  106  moves about the room. 
     From this information, the sound target module  412  determines one or more places to direct sound. The list of locations is provided to the beam shaper  160  to form one or more directional sound beams. One or more phase/time delay elements  416 ( 1 ), . . . ,  416 (K) are provided to manipulate the audio signals provided to the speakers  406 ( 1 )-(S) to cause formation of beams having a desired strength, direction, and duration. For example, in one implementation, by controlling the timing and characteristics of the signals provided to multiple speakers, the sound waves output by the chosen speakers reinforce in the desired direction while canceling in other directions. This reinforcing enables emission of a sound beam in a targeted direction. In this manner, people in that directional sound beam path can more clearly hear the audio sound, while the sound is faint or imperceptible to people in other directions that are not in the sound beam path. In  FIG. 1 , the speaker array  118  is shown outputting several directed sound beams as indicated by the dashed ovals. 
     Continuing our example, suppose the user is watching a movie on the far wall (not shown). A first sound beam  418  and a second sound beam  420  represent respective left and right channels of a stereo signal. The first sound beam  418  may be created through use of 2-3 speakers in the speaker array  118 . The second sound beam  420  may be created by a different collection of speakers, which may or may not include one or more speakers involved in the creation of both beams. The first and second sound beams may be slightly spaced in time to effectuate a stereo experience for the user  106 . For instance, the first sound beam  418  may be delayed slightly relative to the second sound beam  420 , where the delay and order of which speaker is fired first depends in part on the location of the user relative to the speaker array  118  and the surface onto which the movie is projected. 
     A third sound beam  422  is shown output in a rightward direction relative to the speaker array  118 . The sound beam is directed to the wall  414  and reflected back to the user  106 . This third sound beam  422  thereby provides the backend surround sound components for an enhanced audio experience. The speaker array  118  may further emanate base sound waves  424 , essentially serving the function of a woofer in a full spectrum sound experience. 
     Accordingly, the fixed-location speaker array  118  is capable of producing a rich audio experience, such as surround sound and full spectrum stereo. Additionally, the fixed-location speaker array  118  is capable of producing localized sounds within the environment. 
     Illustrative Process 
       FIG. 5  shows an illustrative process  500  of providing an enhanced augmented reality environment using a projection and camera system that shares a common optics path. The processes described herein may be implemented by the architectures described herein, or by other architectures. These processes are illustrated as a collection of blocks in a logical flow graph. Some of the blocks represent operations that can be implemented in hardware, software, or a combination thereof. In the context of software, the blocks represent computer-executable instructions stored on one or more computer-readable storage media that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, components, data structures, and the like that perform particular functions or implement particular abstract data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described blocks can be combined in any order or in parallel to implement the processes. It is understood that the following processes may be implemented with other architectures as well. 
     At  502 , an environment for an augmented reality is analyzed. In one implementation, this may be done automatically, for example, using the spatial analysis module  142 . In another implementation, a map may be formed by physically measuring the dimensions of the environment relative to the ARFN and speaker array and entering these dimensions into an electronic record for consumption by the speaker array controller  158 . 
     At  504  and  506 , locations of one or more users, screens or projection surfaces, and/or other objects are determined. Generally, objects may be any item, person, or thing within the environment being analyzed. Special cases of the objects—people and screens—are called out for discussion purposes. This functionality may be performed, for example, by the tracking and control module  156  on the ARFN  102 . 
     At  508 , sound targets are determined within the environment based, at least in part, on the 3D map and locations of the user(s), screen(s), and/or object(s). This functionality may be performed by the sound target module  412 . 
     At  510 , a subset of one or more speakers from the speaker array is selected depending upon a desired beam shape, direction, and orientation. The beam shaper  160  selects the combination of speakers based on their location on the spherical- or hemispherical-shaped body  402  and ability to direct sound to a select location within the environment so that the sound is more perceptible at the select location than other locations. 
     At  512 , sound is generated and directed at certain target locations within the environment. The various beams may be generated by controlling the individual selected speakers within the speaker array  118 . For instance, a set of 2 or 3 speakers may be used to generate a directional beam of sound by controlling the timing of the sound signal going to each speaker in the set. 
     CONCLUSION 
     Although the subject matter has been described in language specific to structural features, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features described. Rather, the specific features are disclosed as illustrative forms of implementing the claims.