Patent Publication Number: US-8976986-B2

Title: Volume adjustment based on listener position

Description:
BACKGROUND 
     Audio systems can be used in a variety of different applications. For example, modern console gaming systems are configured to take advantage of multi-channel surround sound systems capable of playing different sounds out of several different speakers. 
     SUMMARY 
     The present disclosure is directed to real-time audio adjustments made to influence the perceived volume of a listener. The position of a listener is tracked in real-time. As the position of the listener changes relative to one or more speakers, the individual volumes of the one or more speakers are adjusted according to a predetermined function based on the distance between the listener and the speaker(s). 
     This Summary is provided to introduce a selection of 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 to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example of how perceived volume varies as the distance between a player and a speaker changes. 
         FIG. 2  somewhat schematically shows an example system for tracking the position of a player in accordance with an embodiment of the present disclosure. 
         FIGS. 3A and 3B  show examples of speaker volume adjustments made in response to a changing player position. 
         FIGS. 4A and 4B  show examples of speaker volume adjustments made in response to a position of a player in a surround sound system. 
         FIG. 5  shows an example method of regulating volume based on a position of a player in accordance with an embodiment of the present disclosure. 
         FIGS. 6A and 6B  show example functions for adjusting audio output level as a function of distance. 
         FIG. 7  schematically shows a computing system in accordance with an embodiment of present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to audio attenuation and amplification based on a listener&#39;s position relative to one or more speakers. While described below in the context of a gaming system, it is to be understood that audio attenuation and amplification based on a listener&#39;s position relative to one or more speakers, as described herein, may be used in a number of different applications. 
     Gaming systems incorporating one or more speakers can be controlled at least in part by the movement of a player (i.e., listener) within a physical space. For example, a player holding a motion sensing controller can cause a virtual avatar to swing a bat in game space by swinging the motion sensing controller in world space. As another example, a vision-based system can use one or more cameras to track the movements of the player, and such movements may be translated into game controls. In such systems, as the player moves about a space containing one or more speakers, the sound volume perceived by the player may change. For example, as the distance from a player to a sound source increases (i.e., the player moves away from a speaker), the sound volume perceived by the player may decrease. Likewise, as the distance from a player to a sound source decreases (i.e., the player moves toward a speaker), the sound volume perceived by the player may increase. Thus, the sound volume perceived by the player varies with player position. 
     In such a scenario, the sound volume perceived by the player may be too loud or too quiet when a player gets too close or too far away, respectively, from a speaker. Player discomfort may result when the perceived volume is too loud. When the perceived volume is too quiet, the sound may become inaudible to the player. Furthermore, when there is more than one speaker in the environment, e.g., in a surround sound system, the balance of sound may not be preserved as the player moves about the physical space. These and other issues relating to perceived volume can be detrimental to the player experience. 
     By adjusting speaker volume based on a player position, the sound volume perceived by the player may be regulated to remain in a desired range and balance. The adjusting may include amplifying or attenuating a volume of a sound source or multiple sound sources based on a player&#39;s position. 
       FIG. 1  shows an example of how volume perceived by a player  100  can vary as the position of player  100  changes relative to a speaker  102 . The volume of sound emitted by the speaker  102  is indicated by meter  104  and the sound volume perceived by player  100  is indicated by meter  108 . Such a metering convention is used throughout this disclosure. When a meter is used in conjunction with a speaker (e.g., speaker  102 ), the relative amount of the meter filled with black is indicative of a relative volume of the speaker (i.e., more black corresponds to more output volume and less black corresponds to less output volume). When a meter is used in conjunction with a listener (e.g., player  100 ), the relative amount of the meter filled with black is indicative of a relative volume perceived by the listener (i.e., more black corresponds to louder perceived sounds and less black corresponds to quieter perceived sounds). 
     As shown in  FIG. 1 , when a volume of speaker  102  is held at a constant level, the resulting sounds perceived by player  100  change in proportion to a distance of the player from the speaker. In particular, player  100  perceives relatively loud sounds at position  110  relatively close to speaker  102 , relatively quiet sounds at position  114  relatively far from speaker  102 , and relatively intermediate sounds at position  106  at an intermediate distance from speaker  102 . 
     As described in detail below, the relative volume of a sound source may be modulated in real-time based on a listener&#39;s position in order to regulate the perceived volume of that sound source to the listener. In order to regulate volume in such a manner, a listener&#39;s position in a physical space is tracked relative to one or more sound sources. It is to be understood that virtually any real-time tracking technique can be used without departing from the scope of this disclosure. Furthermore, it is to be understood that real-time adjustments, as described herein, may include a short delay caused by the processing time of a computing system. 
     In one example, a gaming system may track the position of a player holding a motion sensing detector. As another example, a pressure-sensing floor mat may report the position of a player positioned on the mat to a gaming system. As another example, acoustic profiling may be used to track the position of a player. Another example of tracking the position of a player is shown in  FIG. 2 . 
       FIG. 2  shows an example of a vision-based computing system  202  used to track the movements of a player  200 . Computing system  202  may include a gaming console that may be used to play a variety of different games, play one or more different media types, and/or control or manipulate non-game applications. Computing system  202  may also include a display device  206 . Display device  206  may be a high-definition television, for example, and may be used to present visual information to players, such as player  200 . 
     In  FIG. 2 , computing system  202  includes a capture device  204 . Capture device  204  may include any input mechanism which can visually identify the position of a player, e.g., player  200 . For example, capture device  204  may be configured to capture video with depth information via any suitable technique (e.g., time-of-flight, structured light, stereo image, etc.). As such, capture device  204  may include a depth camera, a video camera, stereo cameras, and/or other suitable capture devices. 
     In  FIG. 2 , a player  200  is shown at a first position  210 . Capture device  204  may receive a depth image of the scene shown generally at  208  which includes player  200  at position  210 . The computing system may then recognize player  200  at position  210  in the depth image acquired from capture device  204 . For example, the computing system may use skeletal data or head tracking to identify player  200  in the depth image. Once the system recognizes player  200  at position  210  in the depth image, the system may identify positional information of the player. The positional information may include three-dimensional coordinate data, for example. In some embodiments, computing system  202  may locate a position of a particular player body part or region (e.g., ear, center of head, etc.) within a three-dimensional world space. 
     Capture device  204  may monitor the position of player  200  and/or a particular part of player  200  in real-time by receiving a plurality of depth images of scene  208  containing player  200 . Thus, for example, if player  200  moves to a second position  212  farther away from capture device  204 , another depth image, or series of depth images, may be received by capture device  204 . The depth image(s) of the scene with player  200  at position  212  may then be used by computing system  202  to obtain positional information, e.g., coordinates of player  200  and/or particular part of player  200  within a three-dimensional world space. In this way system  202  may track the position of the player in three-dimensional space in real-time. 
     Based on player position tracking as described above, sound volume emitted from one or more sound sources may be regulated to achieve a desired sound balance perceived by the player.  FIGS. 3A and 3B  show an example of volume regulation as a player  300  moves closer and farther away from a sound source. 
     In  FIGS. 3A and 3B  a computing system  302 , e.g., a gaming system, is shown. In this example, computing system  302  includes a display device  304 , a speaker  306 , and a capture device  308 , e.g., a depth camera. 
     In  FIG. 3A , when player  300  is at a first position  312  relatively close to speaker  306 , the speaker volume is decreased to a level indicated by meter  310 . The decrease in speaker volume compensates for the decreased distance between player  300  and the speaker  306 . As such, the sound volume perceived by player  300  at position  312  can be maintained at a desired level indicated by meter  316 . 
     Likewise, if player  300  moves to a second position relatively far away from speaker  306 , e.g., to position  314  in  FIG. 3B , the speaker volume is increased to a level indicated by meter  310  in  FIG. 3B . The increase in speaker volume compensates for the increased distance between player  300  and the speaker  306 . As such, the sound volume perceived by player  300  at position  314  can be maintained at a desired level indicated by meter  316 . 
     The volume can be automatically regulated in real-time using any suitable method. In some embodiments, a channel-specific audio output level can be adjusted for a particular speaker. In other words, a gaming console or other computing system may adjust a level of an audio output sent to an amplifier so that the resulting volume from the speaker changes without the amplification level of the amplifier changing. In some embodiments, the amplification level of an amplifier may be changed in real-time. 
       FIGS. 4A and 4B  show examples of regulating volume for a situation in which there is a plurality of speakers set up throughout a room, for example in a surround sound system. In such a situation, the concepts described above with reference to  FIGS. 3A and 3B  can be applied to two or more of the speakers in the surround sound system. 
       FIGS. 4A and 4B  show a computing system  406 , e.g., a gaming system, that includes a display device  408 , a capture device  412 , and a plurality of surround sound speakers (e.g., speaker  410   a , speaker  410   b , speaker  410   c , speaker  410   d , speaker  410   e , speaker  410   f , speaker  410   g ). 
     In  FIG. 4A , player  400  is at a first position  402   a  in a room. The position of player  400  may be determined by capture device  412  as described above with regard to  FIG. 2 . The volume levels of the surround sound speakers are adjusted to the levels indicated by respective meters (e.g., meter  414   a , meter  414   b , meter  414   c , meter  414   d , meter  414   e , meter  414   f , meter  414   g ) in response to the position of player  400 . The speaker volume adjustments shown in  FIG. 4A  are based on the respective distances from a given speaker to player  400  as indicated by arrows. The speaker volume adjustments maintain a desired volume and balance of sound as perceived by player  400  at position  402   a.    
     As shown in  FIG. 4B , when player  400  moves to a different position  402   b , as tracked by capture device  204 , the volume levels of speakers  410   a - 410   g  are automatically adjusted in real-time by computing system  406  to the levels indicated by respective meters  414   a - 414   g . The speaker volume adjustments shown in  FIG. 4B  are based on the respective distances from a given speaker to player  400  as indicated by arrows and serve to maintain a desired volume and balance of sound as perceived by player  400  at position  402   b.    
       FIG. 5  shows an example method  500  of regulating volume based on a position of a player in a scenario such as shown in  FIGS. 3A-4B . 
     At  502 , method  500  includes identifying a position of one or more speakers. One or more speaker positions can be identified so that a relative distance between such speakers and a listener can be assessed. 
     At  502   a , method  500  includes emitting an audio signal configured to cause a speaker to produce a test sound. For example, each speaker may emit one or more test sounds with one or more specific frequencies and/or amplitudes. Plural test sounds at different frequencies may be emitted from a speaker to determine the speaker volume levels within different frequency bands (e.g., if one speaker is behind a couch that absorbs high frequency sounds). The test sound(s) from each of two or more speakers may be different so that they can be identified from one another. 
     At  502   b , method  500  includes tracking a position of a moving microphone in a plurality of depth images as captured by capture device  204 , for example. For example, the player may hold a microphone and move about the speaker environment while the microphone listens to the test signal(s). 
     At  502   c , method  500  includes correlating a perceived volume from a speaker with the position of the moving microphone. For example, the volume of a test sound emitted by a speaker as perceived by the moving microphone may be correlated with the position of the moving microphone. This correlation of perceived volume at different locations can be used to estimate a likely position of the speaker. For example, a gradient map of perceived sound can be created, and the speaker position can be estimated to be at a world space position that corresponds to the loudest perceived sounds on the gradient map. 
     The above method  502  of identifying a speaker position is nonlimiting. Virtually any method of identifying the position(s) of one or more speakers can be used without departing from the intended scope of this discloser. As another example, the player may go to the location of each speaker to indicate to the vision system where the speaker is positioned. In still another example, the player may describe the layout of the speakers relative to an initial player position through an interactive diagram on the display device. 
     At  504 , method  500  includes regulating speaker volume based on a position of a player. The position of the player is tracked at  504   a  as described above with regard to  FIG. 2 , for example. For example tracking a position of a player may include recognizing the player in a depth image acquired from a depth camera. Recognizing the player in a depth image may further include identifying a three-dimensional position of the player, for example. 
     At  504   b , method  500  includes, for each of one or more speakers, assessing a changing distance between that speaker and the player. For example, the changing distance between the player and the speakers may be assessed based on a map of speaker positions obtained in a speaker configuration step as described above. Assessing a changing distance between a player and a speaker may include calculating a distance between the position of that speaker and the position of the player at two or more different times. In a surround sound system, such as the examples shown in  FIGS. 4A and 4B , assessment of the changing distance may include assessing a distance between the three-dimensional position of the player and a three-dimensional position of each of a plurality of surround sound speakers. 
     At  504   c , method  500  includes, for each of the one or more speakers, automatically adjusting a volume of that speaker in real-time based on a current distance between that speaker and the player. The automatic adjustment may include adjusting the volume of one or more speakers based on the current distance between the three-dimensional position of the speaker and a three-dimensional position of the player. In one example, the level of a given audio signal may be a title level volume for the given audio output. In another example, the adjustment may be made relative to an the audio level range based on the size of the space formed by the speakers 
     In one example, the volume may be adjusted based on an exponential function of the current distance between a player and a speaker.  FIG. 6A  shows an example exponential function for adjusting audio output of a speaker as a function of the current distance. In  FIG. 6A , as the distance between a player and a sound source increases, the volume of the speaker may be increased exponentially to compensate. An exponential function may be selected to compensate for an estimated inverse-squared decrease in volume as a function of distance. 
     In another example, the volume may be adjusted based on a linear function of the current distance between a player and a speaker.  FIG. 6B  shows an example linear function for adjusting audio output of a speaker as a function of the current distance. In  FIG. 6B  as the distance between a player and a sound source increases, the volume of the speaker may be increased linearly to compensate. 
     The methods and processes described herein may be tied to a variety of different types of computing systems. The computing system  202  described above is a nonlimiting example system which includes a gaming console, display device  206 , and capture device  204 . As another, more general, example,  FIG. 7  schematically shows a computing system  700  that may perform one or more of the player tracking, speaker position identification, and volume regulation methods and processes described herein. Computing system  700  may take a variety of different forms, including, but not limited to, gaming consoles, personal computing systems, and audio/visual theaters, among others. 
     Computing system  700  may include a logic subsystem  702 , a data-holding subsystem  704  operatively connected to the logic subsystem, a display subsystem  706 , and/or a capture device  708 . The computing system may optionally include components not shown in  FIG. 7 , and/or some components shown in  FIG. 7  may be peripheral components that are not integrated into the computing system. 
     Logic subsystem  702  may include one or more physical devices configured to execute one or more instructions. For example, the logic subsystem may be configured to execute one or more instructions that are part of one or more programs, routines, objects, components, data structures, or other logical constructs. Such instructions may be implemented to perform a task, implement a data type, transform the state of one or more devices, or otherwise arrive at a desired result. The logic subsystem may include one or more processors that are configured to execute software instructions. Additionally or alternatively, the logic subsystem may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. The logic subsystem may optionally include individual components that are distributed throughout two or more devices, which may be remotely located in some embodiments. 
     Data-holding subsystem  704  may include one or more physical devices configured to hold data and/or instructions executable by the logic subsystem to implement the herein described methods and processes. When such methods and processes are implemented, the state of data-holding subsystem  704  may be transformed (e.g., to hold different data). Data-holding subsystem  704  may include removable media and/or built-in devices. Data-holding subsystem  704  may include optical memory devices, semiconductor memory devices (e.g., RAM, EEPROM, flash, etc.), and/or magnetic memory devices, among others. Data-holding subsystem  704  may include devices with one or more of the following characteristics: volatile, nonvolatile, dynamic, static, read/write, read-only, random access, sequential access, location addressable, file addressable, and content addressable. In some embodiments, logic subsystem  702  and data-holding subsystem  704  may be integrated into one or more common devices, such as an application specific integrated circuit or a system on a chip. 
       FIG. 7  also shows an aspect of the data-holding subsystem in the form of computer-readable removable media  712 , which may be used to store and/or transfer data and/or instructions executable to implement the herein described methods and processes. 
     Display subsystem  706  may be used to present a visual representation of data held by data-holding subsystem  704 . As the herein described methods and processes change the data held by the data-holding subsystem, and thus transform the state of the data-holding subsystem, the state of display subsystem  706  may likewise be transformed to visually represent changes in the underlying data. Display subsystem  706  may include one or more display devices utilizing virtually any type of technology. Such display devices may be combined with logic subsystem  702  and/or data-holding subsystem  704  in a shared enclosure, or such display devices may be peripheral display devices. 
     Computing system  700  further includes a capture device  708  configured to obtain depth images of one or more targets and/or scenes. Capture device  708  may be configured to capture video with depth information via any suitable technique (e.g., time-of-flight, structured light, stereo image, etc.). As such, capture device  708  may include a depth camera, a video camera, stereo cameras, and/or other suitable capture devices. 
     For example, in time-of-flight analysis, the capture device  708  may emit infrared light to the scene and may then use sensors to detect the backscattered light from the surfaces of the scene. In some cases, pulsed infrared light may be used, wherein the time between an outgoing light pulse and a corresponding incoming light pulse may be measured and used to determine a physical distance from the capture device to a particular location on the scene. In some cases, the phase of the outgoing light wave may be compared to the phase of the incoming light wave to determine a phase shift, and the phase shift may be used to determine a physical distance from the capture device to a particular location in the scene. 
     In another example, time-of-flight analysis may be used to indirectly determine a physical distance from the capture device to a particular location in the scene by analyzing the intensity of the reflected beam of light over time via a technique such as shuttered light pulse imaging. 
     In another example, structured light analysis may be utilized by capture device  708  to capture depth information. In such an analysis, patterned light (e.g., light displayed as a known pattern such as a grid pattern or a stripe pattern) may be projected onto the scene. On the surfaces of the scene, the pattern may become deformed, and this deformation of the pattern may be studied to determine a physical distance from the capture device to a particular location in the scene. 
     In another example, the capture device may include two or more physically separated cameras that view a scene from different angles, to obtain visual stereo data. In such cases, the visual stereo data may be resolved to generate a depth image. 
     In other embodiments, capture device  708  may utilize other technologies to measure and/or calculate depth values. 
     In some embodiments, two or more different cameras may be incorporated into an integrated capture device. For example, a depth camera and a video camera (e.g., RGB video camera) may be incorporated into a common capture device. In some embodiments, two or more separate capture devices may be cooperatively used. For example, a depth camera and a separate video camera may be used. When a video camera is used, it may be used to provide target tracking data, confirmation data for error correction of scene analysis, image capture, face recognition, high-precision tracking of fingers (or other small features), light sensing, and/or other functions. 
     It is to be understood that at least some depth analysis operations may be executed by a logic machine of one or more capture devices. A capture device may include one or more onboard processing units configured to perform one or more depth analysis functions. A capture device may include firmware to facilitate updating such onboard processing logic. 
     Computing system  700  may further include an audio device  710 . Audio device  710  may include one or more audio outputs configured to send audio signals to an amplifier and/or to different speakers in a surround sound system, for example. Audio device  710  may also include a microphone. Logic subsystem  702  may be operatively connected to the audio device  710  and the capture device  708 . 
     It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated may be performed in the sequence illustrated, in other sequences, in parallel, or in some cases omitted. Likewise, the order of the above-described processes may be changed. 
     The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.