Patent Publication Number: US-2022232339-A1

Title: Output control device, output control system, and control method

Description:
This Nonprovisional application claims priority under 35 U.S.C. § 119 on Patent Application No. 2021-005317 filed in Japan on Jan. 15, 2021, the entire contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an output control device, an output control system, and a control method. 
     BACKGROUND ART 
     There has been a technology of controlling an output of audio from a speaker so as to localize a sound formed by the audio, that is, control a position of a “stereo image”. 
     CITATION LIST 
     Patent Literature 
     [Patent Literature 1] 
     Japanese Patent Application Publication Tokukai No. 2015-16787 
     SUMMARY OF INVENTION 
     Technical Problem 
     In recent years, there has been a demand for technologies for providing a user with a more realistic visual and audio experience in augmented reality (AR), mixed reality (MR), or the like. 
     An objective of an aspect of the present disclosure is to provide a realistic video and audio to a passenger of a moving body. 
     Solution to Problem 
     In order to attain the objective, an output control device in accordance with an aspect of the present disclosure is an output control device for controlling a display and a speaker which are provided in an inner space of a moving body includes: a position and orientation identifying section configured to identify (i) a real position of the moving body, the real position being a position in a real space, and (ii) an orientation of the moving body in the real space; a reading section configured to read, from a storage device, virtual space data defining a virtual space in which an audio source object is provided in a three-dimensional map, the audio source object being a three-dimensional object that serves as a virtual audio source; a virtual position determining section configured to determine, in accordance with the real position of the moving body and the orientation of the moving body in the real space, (i) a virtual position of the moving body, the virtual position being a position in the virtual space, and (ii) an orientation of the moving body in the virtual space; a display control section configured to control the display to display, on the basis of (i) the virtual position of the moving body, (ii) the orientation of the moving body in the virtual space, and (iii) a position at which the display is provided, an image of a partial region of the virtual space or an image of a part of an object in the virtual space; and an audio output control section configured to control the speaker to output audio, the audio output control section controlling, on the basis of (i) the orientation of the moving body in the virtual space and (ii) a relative positional relationship between the virtual position of the moving body and the audio source object, a position of a stereo image formed by the audio outputted from the speaker. 
     In order to attain the objective, a control method in accordance with an aspect of the present disclosure is a control method for controlling a display and a speaker which are provided in an inner space of a moving body, the method including: a position and orientation identifying step of identifying (i) a real position of the moving body, the real position being a position in a real space, and (ii) an orientation of the moving body in the real space; a reading step of reading, from a storage device, virtual space data defining a virtual space in which an audio source object is provided in a three-dimensional map, the audio source object being a three-dimensional object that serves as a virtual audio source; a virtual position determining step of determining, in accordance with the real position of the moving body and the orientation of the moving body in the real space, (i) a virtual position of the moving body, the virtual position being a position in the virtual space, and (ii) an orientation of the moving body in the virtual space; a display control step of controlling the display to display, on the basis of (i) the virtual position of the moving body, (ii) the orientation of the moving body in the virtual space, and (iii) a position at which the display is provided, an image of a partial region of the virtual space or an image of a part of an object in the virtual space; and an audio output control step of controlling the speaker to output audio, the audio output control step including controlling, on the basis of (i) the orientation of the moving body in the virtual space and (ii) a relative positional relationship between the virtual position of the moving body and the audio source object, a position of a stereo image formed by the audio outputted from the speaker. 
     With the above configuration and the above process, it is possible to determine a position and an orientation of the moving body in the virtual space in accordance with a position and an orientation of the moving body in the real space. Further, it is possible to cause the display to display an image in accordance with the position and the orientation of the moving body in the virtual space. Further, in a case where the audio source object provided in the virtual space is considered to be a virtual audio source, it is possible to cause a stereo image of audio corresponding to the audio source object to be formed in a position in accordance with a positional relationship between the movable body and the audio source object and relative directions of the moving body and the audio source object in the virtual space. 
     This enables a passenger of the moving body, which is present in the real space, to have an experience as if the audio source object, which is essentially a virtual audio source, is an audio source that is actually present and is uttering a sound. That is, it is possible to provide a realistic video and audio to the passenger of the moving body. 
     The output control device can be configured such that: the position and orientation identifying section periodically updates the real position of the moving body and the orientation of the moving body in the real space; the virtual position determining section updates, in accordance with the real position and the orientation in the real space thus updated, the virtual position and the orientation in the virtual space; the display control section controls the display to display the image of the partial region and the image of the part of the object, each of which has been updated on the basis of the virtual position and the orientation in the virtual space thus updated; and the audio output control section updates the position of the stereo image on the basis of the virtual position and the orientation in the virtual space thus updated. 
     With the above configuration, in a case where the real position and the real orientation of the moving body have changed, the output control device can identify the real position and the orientation in the real space which have changed. The virtual position of the moving body and the orientation of the moving body in the virtual space are determined in accordance with the real position and the orientation in the real space. A position of an image of a region to be displayed on the display or an image of an object to be displayed on the display and a position of a stereo image formed by audio outputted by the speaker are determined in accordance with the virtual position of the moving body and the orientation of the moving body in the virtual space. 
     As such, with the above configuration, in a case where the real position and the real orientation of the moving body have changed, it is possible to reflect such changes in image display and audio output. 
     The output control device can be configured such that the audio output control section controls the speaker so that the greater a distance between the virtual position and the audio source object in the virtual space, the smaller a volume in which audio corresponding to the audio source object is outputted. 
     The above configuration enables a positional relationship between the moving body and an audio source object to be represented by a volume of a sound. This enables a passenger of the moving body to experience more realistic audio. 
     The output control device can be configured such that: the virtual position determining section determines the virtual position so that a positional relationship between a given reference point in the virtual space and the virtual position is similar to a positional relationship between a given reference point in the real space and the real position; and the image of the partial region or the image of the part of the object, each of which the display is controlled by the display control section to display, is determined so that the virtual space is displayed on the same scale as the real space. 
     The above configuration enables a passenger of the moving body to experience a visual effect that makes the passenger feel as if the real space and the virtual space have merged. 
     In order to attain the objective, an output control system in accordance with an aspect of the present disclosure is an output control device, including: the output control device; a positioning device configured to measure data pertaining to the real position of the moving body; the storage device; the display; and the speaker, the position and orientation identifying section of the output control device identifying the real position of the moving body and the orientation of the moving body in the real space on the basis of the data pertaining to the real position and obtained from the positioning device. With the above configuration, it is possible to bring about an effect similar to that of the output control device. 
     Advantageous Effects of Invention 
     An aspect of the present disclosure makes it possible to provide a realistic video and audio to a passenger of a moving body. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating an example of an operation of an output control system in accordance with Embodiment 1 of the present disclosure. 
         FIG. 2  is a block diagram illustrating configurations of main parts of various devices included in the output control system. 
         FIG. 3  is a view illustrating a specific example of a virtual space in accordance with Embodiment 1 of the present disclosure. 
         FIG. 4  is a view illustrating an example of how displays and speakers are provided in a moving body in accordance with Embodiment 1 of the present disclosure. 
         FIG. 5  is a flowchart illustrating a flow of a process carried out by an output control device in accordance with Embodiment 1 of the present disclosure. 
         FIG. 6  shows views illustrating a change in relative positional relationship between a moving body and an audio source object in a virtual space and a change in position of a stereo image in a real space. 
         FIG. 7  is a block diagram illustrating configurations of main parts of various devices included in an output control system in accordance with Embodiment 2 of the present disclosure. 
         FIG. 8  is a view illustrating an example of how vibrators are provided in the output control system in accordance with Embodiment 2 of the present disclosure. 
         FIG. 9  is a block diagram illustrating configurations of main parts of various devices included in an output control system in accordance with Embodiment 3 of the present disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiment 1 
     An output control system in accordance with Embodiment 1 is a system for controlling an output of an image and audio in an inner space of a moving body. The output control system provides a passenger of the moving body with an image and audio of a virtual space that is linked with a real world. That is, an output control system  100  provides mixed reality (MR) in an inner space of a moving body. 
     The following description will discuss in detail, with reference to  FIGS. 1 through 6 , configurations and operations of various devices included in the output control system in accordance with Embodiment 1. As used herein, the term “image” encompasses both a still image and a moving image. As used herein, the term “audio” refers to all kinds of sound including not only a human voice but also a sound effect, ambient sound, back ground music, and the like. 
     &lt;&lt;Example of Operation of System&gt;&gt; 
     First, the following description will provide an overview of an operation of the output control system  100 .  FIG. 1  is a view illustrating an example of an operation of the output control system  100  in accordance with Embodiment 1.  FIG. 1  is a view of an inner space of a moving body  9 , which includes the output control system  100 , as viewed from behind a passenger P 1  staying in the inner space. As illustrated in  FIG. 1 , seats S 1 , a driver&#39;s seat S 2 , displays  4 , and speakers  5  are provided in the inner space of the moving body  9 . Note that the seats S 1  and the driver&#39;s seat S 2  are not an essential part of the output control system  100 . The number of display(s)  4  and the number of speaker(s)  5  are not limited to those shown in  FIG. 1 . 
     (Inner Space of Moving Body  9 ) 
     In the case of the inner space of the moving body  9  illustrated in  FIG. 1 , the displays  4  are provided on at least two wall surfaces that are neither in front of the driver&#39;s seat nor behind the seats S 1 . In the case illustrated in  FIG. 1 , a window, not a display  4 , is provided in front of the driver&#39;s seat. In the case illustrated in  FIG. 1 , there is no limitation on a structure of a wall behind the seats S 1 . On one of the seats S 1 , the passenger P 1  who stays in the inner space of the moving body  9  is seated. Hereinafter, a “passenger P 1  who stays in the inner space of the moving body  9 ” will be referred to simply as a “passenger”. The output control system  100  controls each of the displays  4  to display an image in which scenery of a virtual space is drawn. The output control system  100  controls each of the speakers  5  to output audio for representing the virtual space. 
     (Virtual Space) 
     As used herein, the term “virtual space” refers to a three-dimensional space model which includes (i) a three-dimensional map of a predetermined range and a three-dimensional object(s) of various kinds provided in the three-dimensional map. The output control system  100  determines a position and an orientation of the moving body  9  in the virtual space in accordance with a position and an orientation of the moving body  9  in a real space (this will be described later in detail). Hereinafter, for convenience, a position in the real space will be referred to as a “real position”. A position in the virtual space will be referred to as a “virtual position”. An orientation in the real space will be referred to as a “real orientation”, and an orientation in the virtual space will be referred to as a “virtual orientation”. The output control system  100  controls, in accordance with the virtual position and the virtual orientation of the moving body  9  which have been determined, image display carried out by the displays  4  and audio output carried out by the speakers  5 . 
     In the present specification, the real space and the virtual space may be different from each other, or may be the same. For example, the virtual space can be a space model that is an accurate copy of the real space in which the moving body  9  actually travels, or can be a space model that represents a space in which the moving body  9  cannot possibly travel in reality, such as at the bottom of the sea or in the sky. In the virtual space, a map and an object each representing an item or an event that exists in the real space can coexist with a map and an object each representing an item or an event that does not exist in the real space. 
     (Display Control and Audio Output Control) 
     The output control system  100  generates the image in which the scenery of the virtual space is drawn, which scenery would be seen from the moving body  9  in the virtual position and the virtual orientation. The output control system  100  controls each of the displays  4  to display the image thus generated. For example, a region of the virtual space drawn by the output control system  100  is determined in accordance with (i) the virtual position and the virtual orientation of the moving body  9 , (ii) a position and an orientation of each of the displays  4  in the real space, and (iii) a size and a shape of each of the displays  4 . 
     In Embodiment 1, unless otherwise indicated, a three-dimensional map in the virtual space and a three-dimensional object(s) in the virtual space are a map and an object(s) that can be drawn as scenery (i.e., that are not transparent). Note, however, that at least a part of the three-dimensional map in the virtual space can be a transparent map not displayed on the displays  4 . Further, at least a part of the three-dimensional object(s) in the virtual space can be a transparent object not displayed on the displays  4 . 
     The output control system  100  controls the speakers  5  to output audio for representing the virtual space. The output control system  100  ( i ) identifies audio that would be heard by the passenger if the passenger was present in the virtual position and the virtual orientation of the moving body  9  and (ii) controls the speakers  5  to output the audio so as to recreate a way in which the audio would be heard in the virtual position and the virtual orientation. 
     More specifically, the output control system  100  controls the speakers  5  to control a position of a stereo image formed by the outputted audio. For example, the output control system  100  controls the speakers  5  so that a direction of a position at which the stereo image is formed in the inner space of the moving body  9  is the same as a direction from the virtual position and the virtual orientation of the moving body  9  to an audio source object. In the example illustrated in  FIG. 1 , in order to represent utterance of audio from a mammoth (i.e., an object in the virtual space) displayed on the displays  4 , the output control system  100  controls the speakers  5  so as to form a stereo image near a position at which the mammoth is displayed. 
     (Movement of Moving Body  9  and Changes in Image and Audio) 
     The output control system  100  regularly identifies the real position and the real orientation of the moving body  9  and regularly updates the virtual position and the virtual orientation of the moving body  9  in accordance with the real position and the real orientation. Further, in accordance with the virtual position and the virtual orientation thus updated, the output control system  100  regularly updates also an image to be displayed on the displays  4 , audio to be outputted by the speakers  5 , and a position of a stereo image of the audio. Thus, the output control system  100  can change, in real time in accordance with an operation of the moving body  9 , display of each of the displays  4  and output of audio from each of the speakers  5 . 
     For example, when the moving body  9  is traveling, the output control system  100  can display scenery of the virtual space which changes in accordance with the traveling of the moving body  9 . Further, for example, the output control system  100  can represent, by a change in position at which the stereo image is formed, (i) a change in relative positions of the moving body  9  and an object from which audio would be uttered and (ii) a change in relative directions of the moving body  9  and the object. The output control system  100  can thus cause the passenger P 1  to experience an image and immersive audio which make the passenger P 1  feel as if the moving body  9  is traveling in the virtual space. 
     &lt;&lt;Configuration of Main Parts&gt;&gt; 
     The following description will discuss configurations of various devices included in the output control system  100 .  FIG. 2  is a block diagram illustrating configurations of main parts of the various devices included in the output control system  100  in accordance with Embodiment 1. The output control system  100  includes an output control device  1 A, a positioning device  2 , a storage device  3 , the displays  4 , and the speakers  5 . At least the output control device  1 A, the displays  4 , and the speakers  5  are provided in the inner space of the moving body  9 . In the example of Embodiment 1, the positioning device  2  and the storage device  3  are also provided in the inner space of the moving body  9 . Note that the storage device  3  can be included in the output control device  1 A. 
     (Positioning Device  2 ) 
     The positioning device  2  collects information pertaining to the real position of the moving body  9 . The positioning device  2  supplies, to the output control device  1 A, the information (which will also be referred to as positioning data) obtained by measurement. A specific structure of the positioning device  2  is not particularly limited. For example, the positioning device  2  can be a light detection and ranging (DAR) which detects a structure in the vicinity of the moving body  9 . In this case, the positioning data is information indicative of a size and a shape of the structure in the vicinity of the moving body  9 . Further, the positioning device  2  can be a GPS receiver. In this case, the positioning data is information indicative of a latitude and a longitude received from a GPS satellite. 
     (Storage Device  3 ) 
     The storage device  3  is a device in which various pieces of information necessary for an operation of the output control device  1 A are stored. The storage device  3  contains at least virtual space data  31 , audio source setting information  32 , and audio data  33 . The storage device  3  can contain map data  34 . 
     The virtual space data  31  is a set of various data pertaining to construction of the virtual space. The virtual space data  31  contains, for example, map data of the virtual space and data of the object provided in the virtual space. The virtual space data  31  is prepared and stored in the storage device  3  in advance. In Embodiment 1, one type of virtual space data  31  is stored in the storage device  3 . Note, however, that a plurality of types of virtual space data  31  may be stored in the storage device  3 . 
     (Specific Example of Virtual Space) 
       FIG. 3  is a view illustrating a specific example of the virtual space.  FIG. 3  is a two-dimensional picture schematically illustrating the virtual space, but the actual virtual space is a three-dimensional model. In  FIG. 3 , the position and the orientation of the moving body  9  in the virtual space are also illustrated. 
     In the virtual space, at least one audio source object, which is set as a virtual audio source, is provided. The term “virtual audio source” refers to a source of a sound in the virtual space. Note that the term “source of a sound” herein does not mean that the sound is actually generated, but means a setting where the sound is generated. 
     In the example illustrated in  FIG. 3 , an object B 1  of a mammoth, an object B 2  of a building, and an object B 3  of a house are each an audio source object. Thus, an audio source object can be an immobile object, or can be an object that regularly or irregularly moves. In cases other than the example illustrated in  FIG. 3 , for example, in a case where the virtual space is a space representing a road and a town, an audio source space can be an object in a fixed position, such as a railroad crossing, or can be an object whose position changes, such as a train, an automobile, or a person. 
     Note that an audio source object can be an object that can be drawn, i.e., displayed on the displays  4 , or can be a transparent object that cannot be drawn. For example, the object B 1  of the mammoth illustrated in  FIG. 3  can be an object that can be displayed on the displays  4  and that is an audio source object. Alternatively, for example, the object B 1  of the mammoth illustrated in  FIG. 3  can be an object that can be displayed on the displays  4  and that is not an audio source object. Then, an audio source object of audio related to the object B 1 , such as audio uttered by the mammoth or the sound of footsteps of the mammoth, can be provided as a transparent object which is different from the object B 1 . 
     Which one(s) of the objects included in the virtual space data  31  is/are an audio source object(s) is defined by the audio source setting information  32 . The audio source setting information  32  is information indicative of assignment of audio data  33  to an audio source object. More specifically, the audio source setting information  32  is information in which identification information of an object that is an audio source object and identification information of audio data  33  are stored in association with each other. Examples of identification information of an object include an ID assigned to each object in the virtual space data  31 . Examples of identification information of audio data  33  include a file name of the audio data  33 . 
     The audio source setting information  32  can include information indicative of an audio volume of audio data  33 . For example, the audio source setting information  32  can be information in which identification information of audio data  33  and information indicative of a set audio volume of the audio data  33  are stored in association with identification information of an audio source object. The set audio volume indicates a playback volume in which the audio data  33  is played back in a case where a distance from the virtual position of the moving body  9  to the audio source object is zero. The set audio volume can be set, for example, to a numerical value of 1 to 100. In this case, the set audio volume can be such that 1 is the smallest audio volume, and 100 is the largest audio volume. 
     The audio data  33  is data of audio outputted from the speakers  5 . The audio data  33  is read out by the output control device  1 A to be played back or processed (e.g. addition of an effect) at an audio output control section  15  (described later), and then is outputted from the speaker  5 . In a case where the audio source setting information  32  includes a set audio volume of the audio data  33 , the audio output control section  15  can attenuate the audio volume of the audio data  33  in accordance with the distance from the virtual position of the moving body  9  to the audio source object in the virtual space. 
     The map data  34  is data including information such as a geography of an area in which the moving body  9  can travel, a shape of a road, and a structure that serves as a landmark. In the output control system  100 , a method for obtaining the map data  34  is not particularly limited. For example, in a case where a car navigation system is included in the moving body  9 , the storage device  3  can be connected to the car navigation system and download the map data  34  in advance. 
     The map data  34  is used in identifying the real position of the moving body  9  on the basis of positioning data. As such, in a case where the real position of the moving body  9  is directly known from the positioning data, the storage device  3  need not store the map data  34 . For example, in a case where the positioning device  2  is a GPS receiver, the positioning data indicates a latitude and a longitude, and the map data  34  is thus not essential information. 
     (Output Control Device  1 A) 
     The output control device  1 A is a device which centrally controls the displays  4  and the speakers  5 . The output control device  1 A generates an image in accordance with the real position and the real orientation of the moving body  9 , and supplies the image to the displays  4 . The output control device  1 A determines, in accordance with the real position and the real orientation of the moving body  9 , audio to be outputted from the speakers  5 , and determines a mode of output of the audio from the speakers  5 . Examples of the “mode of output of the audio” herein include a position of a stereo image formed by the audio. The output control device  1 A supplies the speakers  5  with audio to be outputted and controls output of the audio from the speakers  5  so that a stereo image is formed in a position determined by the output control device  1 A. 
     (Details of Configuration of Output Control Device  1 A) 
     More specifically, the output control device  1 A includes a position and orientation identifying section  11 , a reading section  12 , a spatial processing section  13 , a display control section  14 , and the audio output control section  15 . 
     The position and orientation identifying section  11  identifies the real position and the real orientation on the basis of the positioning data obtained from the positioning device  2 . The position and orientation identifying section  11  supplies the spatial processing section  13  with information indicative of the real position thus identified and information indicative of the real orientation thus identified. 
     The position and orientation identifying section  11  identifies the real position, for example, in the following manner. In a case where the positioning device  2  is a LiDAR, the position and orientation identifying section  11  identifies the real position of the moving body  9  by comparing positioning data of the LiDAR with the map data  34  stored in the storage device  3 . In a case where the positioning device  2  is a GPS receiver and positioning data is information already indicative of the real position (e.g. a latitude and a longitude) of the moving body  9 , the position and orientation identifying section  11  uses the obtained positioning data as it is as information indicative of the real position. 
     The position and orientation identifying section  11  identifies the real orientation, for example, in the following manner. In a case where the positioning device  2  is a LiDAR, comparison of the positioning data and the map data  34  in identifying the real position enables identifying the real orientation at the same time. In a case where the positioning device  2  is another device which is not a LiDAR, the position and orientation identifying section  11  first carries out identification of the real position on the basis of the positioning data a plurality of times, and compares the thus obtained real positions to identify a direction in which the real position moves. The position and orientation identifying section  11  identifies the direction in which the real position of the moving body  9  moves to be a traveling direction of the moving body  9 , i.e., the real orientation of the moving body  9 . In a case where the real position has not changed over a plurality of times of identification, that is, in a case where the moving body  9  has not moved, the real orientation last identified can be used as it is by the position and orientation identifying section  11 . 
     The reading section  12  reads the virtual space data  31  from the storage device  3  and supplies the virtual space data  31  to the spatial processing section  13 . A timing at which the reading section  12  reads the virtual space data  31  and a timing at which the reading section  12  supplies the virtual space data  31  to the spatial processing section  13  are not particularly limited. For example, the reading of the virtual space data  31  and the supply of the virtual space data  31  to the spatial processing section  13  by the reading section  12  can be carried out in response to a request from the spatial processing section  13 , or can be carried out every time the virtual space data  31  is updated. In a case where a plurality of types of virtual space data  31  are stored in the storage device  3 , the reading section  12  can determine which type of virtual space data  31  is to be read. 
     The spatial processing section  13  carries out various processes using the virtual space data  31 . More specifically, the spatial processing section  13  includes a virtual position determining section  131 , an audio source determining section  132 , and a display image preparing section  133 . 
     The virtual position determining section  131  determines a virtual position and a virtual orientation of the moving body  9  in accordance with the real position and the real orientation of the moving body  9  supplied from the position and orientation identifying section  11 . The virtual position determining section  131  supplies information indicative of the virtual position and information indicative of the virtual orientation to the audio output control section  15 , the audio source determining section  132 , and the display image preparing section  133 . 
     A specific method by which the virtual position determining section  131  determines the virtual position and the virtual orientation can be determined as appropriate in accordance with a type and a characteristic of the virtual space data  31 . For example, it is preferable that the virtual position determining section  131  define in advance that a given point in the real space and a given point in the virtual space are each a reference point, and determine the virtual position so that a positional relationship between the reference point in the virtual space and the virtual position is similar to a positional relationship between the reference point in the real space and the real position. A method for prescribing the above reference points is not particularly limited. For example, a point of a certain latitude and a certain longitude on a map can be prescribed to be a reference point, or a real position and a virtual position that are initially determined by the position and orientation identifying section  11  and the virtual position determining section  131  can thereafter be used as reference points. 
     In a case where the display image preparing section  133  (described later) draws the virtual space on the same scale as the real space, the virtual position determining section  131  can determine the virtual position of the moving body  9  so that the virtual position substantially coincides with the real position of the moving body  9 , and the virtual position determining section  131  can determine the virtual orientation of the moving body  9  so that the virtual orientation substantially coincides with the real orientation of the moving body  9 . This enables the position of the moving body  9  in the real space and the position of the moving body  9  in the virtual space to be linked to each other. 
     The audio source determining section  132  selects an audio source object from which audio would be heard by the passenger if the passenger was in the virtual position (and the virtual orientation) of the moving body  9 . In other words, the audio source determining section  132  determines an audio source object corresponding to the audio data  33  to be outputted as audio. The audio source determining section  132  selects, for example, an audio source object that is present within a predetermined range from the virtual position of the moving body  9  in the virtual space. The audio source determining section  132  identifies, on the basis of the virtual space data  31 , identification information of the audio source object thus selected. The audio source determining section  132  supplies the audio output control section  15  with the thus identified identification information of the audio source object. 
     The audio source determining section  132  can select an audio source object on the basis of (i) a set audio volume of audio data  33  assigned to the audio source object and (ii) a distance from the virtual position of the moving body  9  to the audio source object. For example, the audio source determining section  132  can select an audio source object by carrying out processes of the following steps  1  through  4 . 
     Step  1 : Calculate distances from a virtual position of the moving body  9  to respective audio source objects.
 
Step  2 : On the basis of the audio source setting information  32 , identify a set audio volume of audio data  33  corresponding to each of the audio source objects.
 
Step  3 : Identify, for each of the audio source objects, a playback volume on the basis of the distance calculated in Step  1  and the set audio volume. For example, the greater the distance calculated in Step  1  is, the more the audio source determining section  132  can attenuate the set audio volume identified in Step  2 . In a case where the distance is zero, the set audio volume itself is used as a playback volume.
 
Step  4 : an audio source object whose playback volume is not lower than a threshold is selected as the “audio source object corresponding to the audio data  33  to be outputted as audio.”
 
     The “distances from a virtual position of the moving body  9  to respective audio source objects” can each be an absolute distance, or can be a relative distance. Step  1  and Step  2  can be carried out in any order. The threshold in Step  4  can be set as appropriate. The audio source determining section  132  can supply the audio output control section  15  with the playback volume identified in Step  3 . 
     According to the above steps, even with respect to, for example, an audio source object that is very distant from the moving body  9  in the virtual space, audio data  33  assigned to the audio source object can be outputted in a case where a playback volume of the audio data  33  is not less than the threshold. As such, audio heard in the distance, such as the sound of fireworks or a siren, can be more accurately reproduced. 
     The display image preparing section  133  prepares, in accordance with the virtual position and the virtual orientation of the moving body  9 , an image to be displayed by a display  4 . The display image preparing section  133  supplies the image thus prepared to the display control section  14 . Note that the display image preparing section  133  can instruct the display control section  14  as to a timing for displaying the image thus supplied. In a case where a plurality of displays  4  are provided, the display image preparing section  133 , when supplying an image, can instruct the display control section  14  as to which of the plurality of displays  4  the image is to be displayed on. 
     For example, the display image preparing section  133  provides, in the virtual space, virtual cameras whose fields of view correspond to the respective displays  4 , and draws an area captured by each of the virtual cameras as a display image to be displayed on a display  4  corresponding to the each of the virtual cameras. A position and orientation of each of the virtual cameras, and a shape and width of the field of view of each of the virtual cameras are determined on the basis of the following (1) to (3). 
     (1) The virtual position and the virtual orientation of the moving body  9   
     (2) A position and an orientation of each display  4  in the real space 
     (3) A size and a shape of each display  4   
     Note that the output control system  100  can include a vehicle interior camera and/or a vehicle interior sensor capable of detecting a position of the head of a passenger by image capturing, measurement, or the like. The output control device  1 A can be connected to the vehicle interior camera and/or the vehicle interior sensor. The spatial processing section  13  of the output control device  1 A can identify a position of the head of a passenger on the basis of an image captured by the vehicle interior camera and/or a result of measurement by the vehicle interior sensor. 
     In a case where the spatial processing section  13  identifies a position of the head of a passenger, a region to be cut out from the captured image can be determined by the display image preparing section  133  on the basis of the position of the head of the passenger in addition to the above (1) to (3). This enables each of the displays  4  to display an image in accordance with a height of the passenger. 
     Specifically, the following description will discuss the displayed image on the basis of the example illustrated in  FIG. 1 . When a traveling direction of the moving body  9  is defined as “front” and a direction opposite to the traveling direction is defined as “back”, the direction of the driver&#39;s seat S 2  in the moving body  9  is front in the real space illustrated in  FIG. 1 . The displays  4  are provided substantially vertically on a right wall surface and a back wall surface, respectively, in the inner space of the moving body  9 . In this case, the display image preparing section  133  prepares, for the display  4  provided on the right wall surface in the inner space, an image in which scenery on the right of the moving body  9  in the virtual space is drawn. Further, the display image preparing section  133  prepares, for the display  4  provided on the back wall surface in the inner space, an image in which scenery behind the moving body  9  in the virtual space is drawn. 
     Thus, as illustrated in  FIG. 1 , scenery on the right to behind the moving body  9  in the virtual space is displayed by the two displays  4 . That is, from the viewpoint of the passenger P 1 , the passenger P 1  can see scenery of the virtual space through the displays  4  together with real scenery seen through the window at the driver&#39;s seat. Note that the term “scenery of the virtual space” herein of course contains an object(s) as well as a map. For example, in a case where all or part of the three-dimensional map is a transparent map which is not drawn, the display image preparing section  133  can prepare an image in which a part of the object(s) in the virtual space is drawn, and supply the image to the display control section  14 . 
     Note that the display image preparing section  133  can determine a magnification of each of the virtual cameras so that the virtual space is displayed on the same scale as the real space. In other words, when drawing the scenery of the virtual space, the display image preparing section  133  can enlarge or reduce the scenery so that the virtual space is displayed on the same scale as the real space on the displays  4 . This enables a passenger of the moving body to experience a visual effect that makes the passenger feel as if the real space and the virtual space have merged. Further, in a case where the moving body  9  is traveling, it is possible to prevent a passenger from suffering from what is known as “3D sickness”, since the scenery of the real space and the scenery of the virtual space move at the same speed. 
     The display control section  14  controls each of the displays  4  to display an image supplied from the display image preparing section  133  of the spatial processing section  13 . In a case where the display image preparing section  133  has provided an instruction as to a timing for displaying an image on each of the displays  4 , the display control section  14  follows the instruction and controls each of the displays  4  to display the image at the specified timing. In a case where a plurality of displays  4  are provided, the display control section  14  carries out control in accordance with an instruction from the spatial processing section  13  as to which image is to be displayed on which of the plurality of displays  4 . 
     The audio output control section  15  carries out various processes related to audio output and formation of a stereo image. More specifically, the audio output control section  15  includes a playback section  151 , a stereo image control section  152 , and an assignment determining section  153 . 
     The playback section  151  plays back audio data  33  assigned to the audio source object determined by the audio source determining section  132 . More specifically, the playback section  151  first identifies audio data  33  assigned to the audio source object determined by the audio source determining section  132 , by searching the audio source setting information  32  in the storage device  3  with use of the identification information of the audio source object as a key. Subsequently, the playback section  151  reads out the thus identified audio data  33  from the storage device  3  and plays back the audio data  33 . The playback section  151  sequentially supplies audio to the stereo image control section  152  while playing back the audio. The playback section  151  can sequentially supply the audio played back also to the assignment determining section  153 . 
     In a case where there are a plurality of audio source objects determined by the audio source determining section  132 , that is, in case where there are a plurality of audio data  33  to be played back, the playback section  151  supplies the plurality of audio data  33  individually to the stereo image control section  152  (and the assignment determining section  153 ) while playing back the plurality of audio data  33  individually. In a case where the audio output control section  15  has received, from the audio source determining section  132 , information indicative of playback volumes of audio data  33 , the playback section  151  can play back each audio data  33  at a playback volume determined for the each audio data  33 . 
     The stereo image control section  152  determines a position at which a stereo image of outputted audio is formed. In a case where a plurality of audio have been simultaneously supplied from the playback section  151 , the stereo image control section  152  can determine, individually for each audio, a position at which a stereo image is formed. The position of a stereo image can be determined by the stereo image control section  152  in real time. That is, the stereo image control section  152  can control, in real time, a position at which a stereo image of the audio data  33  outputted is formed. 
     Specifically, the stereo image control section  152  determines, on the basis of at least the following (1) and (2), a position at which a stereo image is formed. 
     (1) The virtual orientation of the moving body  9  determined by the virtual position determining section  131   
     (2) A relative positional relationship between the virtual position of the moving body  9  and the audio source object 
     Further, the stereo image control section  152  can correct the position of the stereo image on the basis of assignment to the speakers  5  determined by the assignment determining section  153  (described later). 
     The assignment determining section  153  determines, in real time, a speaker  5  from which the audio sequentially supplied from the playback section  151  is to be outputted (that is, a speaker  5  to which the audio to be played back is to be assigned). In a case where there is only one speaker  5  provided in the moving body  9 , the audio output control section  15  need not include the assignment determining section  153 . In a case where a plurality of audio have been simultaneously supplied from the playback section  151 , the assignment determining section  153  can determine assignment to a speaker  5  individually for each audio. The assignment determining section  153  can feedback, to the stereo image control section  152 , determined assignment to the speakers  5 . 
     When the playback of the audio data  33  to be outputted, the position at which the stereo image is to be formed, and the assignment to the speakers  5  are thus determined by the audio output control section  15 , the audio output control section  15  instructs the speakers  5  to carry out audio output in accordance with the above assignment. In so doing, the audio output control section  15  also provides an instruction on an actual volume of audio outputted from each of the speakers  5  and a mode of output from each of the speakers  5 . In this manner, the audio output control section  15  can create, with use of the speakers  5 , a stereo image in a position determined by the stereo image control section  152 . 
     (Displays  4  and Speakers  5 ) 
     The displays  4  are each a display device which displays an image under the control of the output control device  1 A. A type of each of the displays  4  is not particularly limited. For example, the displays  4  can each be a transparent display. The speakers  5  are each an audio output device which outputs audio under the control of the output control device  1 A. A type of each of the speakers  5  is not particularly limited, but the speakers  5  are audio output devices which are capable of localizing a sound, i.e., forming a stereo image, by themselves or in cooperation between the audio output devices. The speakers  5  are each an audio output device capable of adjusting a direction in which audio is outputted, a volume of audio output, and the like to change a position where a stereo image is formed. 
       FIG. 4  is a view illustrating an example of how the displays  4  and the speakers  5  are provided in the moving body  9 .  FIG. 4  is a view of the moving body  9  as viewed from a ceiling surface of the moving body  9 . The displays  4  and the speakers  5  are provided, for example as illustrated in  FIG. 4 , on wall surfaces of the moving body  9  so as to surround the seats S 1  on which the passenger P 1  sits. 
     In a more specific example, in the inner space of the moving body  9 , for example, at least one of three wall surfaces that are not the wall surface in the traveling direction is provided with a display  4  which is substantially parallel to the at least one of the three wall surfaces. A speaker  5  is provided, for example, on at least one of the wall surfaces and/or on the ceiling surface in the inner space of the moving body  9 . The position(s) of the display(s)  4  and the position(s) of the speaker(s)  5  are not limited to these examples. For example, some of the displays  4  and/or the speakers  5  can be provided on a floor surface of the moving body  9 . 
     The position, size, and shape of a display  4  can be freely determined, provided that the operation of the moving body  9  is not negatively affected. For example, in a case where the moving body  9  is manually driven, a window can be provided in front of the driver&#39;s seat S 2 , and displays  4  can be provided on other wall surfaces in the inner space, as illustrated in  FIGS. 1 and 4 . Alternatively, for example, in a case where the moving body  9  is completely automatically driven, the driver&#39;s seat S 2  is not present. In this case, all of the wall surfaces in the inner space of the moving body  9  can be provided with displays  4 . However, to provide the foregoing MR, it is preferable that the displays  4  be provided so that scenery of the real world is seen through at least a part of the windows of the moving body  9 . 
     A height at which a display  4  is provided and an orientation of the display  4  are not particularly limited. It is preferable, however, that a display  4  be provided at such a height and in such an orientation that the passenger P 1  can easily enjoy an image on the display  4 . Further, a height at which each of the speakers  5  is provided and an orientation of each of the speakers  5  are not particularly limited, provided that the speakers  5  can cooperate with each other to form a stereo image in an appropriate position. In the examples illustrated in  FIGS. 1 and 4 , each of the displays  4  and each of the speakers  5  are devices independent of each other. However, each of the displays  4  and each of the speakers  5  can be integrally formed. 
     &lt;&lt;Flow of Process&gt;&gt; 
       FIG. 5  is a flowchart illustrating a flow of a process carried out by the output control device  1 A. The timing of starting the process illustrated in  FIG. 5  is not particularly limited. For example, the output control device  1 A can start the process illustrated in  FIG. 5  when an engine of the moving body  9  is driven. Further, the output control device  1 A can start the process illustrated in  FIG. 5  by being triggered by a predetermined input operation of a passenger, a driver of the moving body  9 , or the like via an input device (not illustrated) included in the moving body  9 . 
     First, the reading section  12  reads virtual space data  31  from the storage device  3  (S 11 ). The reading section  12  supplies the virtual space data  31  thus read to the spatial processing section  13 . 
     Subsequently, the position and orientation identifying section  11  identifies a real position and a real orientation of the moving body  9  on the basis of positioning data obtained from the positioning device  2  (S 12 ). The position and orientation identifying section  11  supplies the real position and the real orientation thus identified to the spatial processing section  13 . 
     The virtual position determining section  131  of the spatial processing section  13  determines a virtual position and a virtual orientation in accordance with the real position and the real orientation thus supplied (S 13 ). The virtual position determining section  131  supplies the virtual position and the virtual orientation thus determined to the audio output control section  15 , the audio source determining section  132 , and the display image preparing section  133 . 
     Then, a set of processes shown in S 21  to S 23  related to display control and a set of processes shown in S 31  to S 33  related to audio output control are carried out in any order or carried out in parallel. 
     The display image preparing section  133  determines a point at which a virtual camera is provided and an orientation of the virtual camera in the virtual space defined by the virtual space data  31  (S 21 ). The number of virtual cameras thus provided corresponds to the number of displays  4 , and the orientation of each of the virtual cameras is determined. 
     Subsequently, the display image preparing section  133  prepares an image to be displayed on each of the displays  4 , by drawing a region included in the virtual space and captured by each of the virtual cameras (S 22 ). The display image preparing section  133  supplies the image thus prepared to the display control section  14 . The display control section  14  controls the displays  4  to display the images supplied from the display image preparing section  133  (S 23 ). 
     The audio source determining section  132  determines, in accordance with the virtual position and the virtual orientation supplied from the virtual position determining section  131 , an audio source object with respect to which assigned audio is to be outputted (S 31 ). The audio source determining section  132  supplies identification information of the audio source object thus determined to the audio output control section  15 . 
     The playback section  151  of the audio output control section  15  identifies, on the basis of the identification information thus supplied, audio data  33  to be played back, and plays back the audio data. While playing back audio, the playback section  151  sequentially supplies the audio to the stereo image control section  152  (and the assignment determining section  153 ). 
     The stereo image control section  152  determines, on the basis of the virtual orientation of the moving body  9  and a relative positional relationship between the virtual position of the moving body  9  and the audio source object, a position of a stereo image of audio to be outputted (S 32 ). The stereo image control section  152  notifies the assignment determining section  153  of the thus determined position at which the stereo image is to be formed. The assignment determining section  153  determines a speaker  5  from which the audio played back by the playback section  151  is to be outputted. That is, the assignment determining section  153  assigns, to at least one speaker  5 , the audio which is being played back. The audio output control section  15  controls each of the at least one speaker  5  in accordance with the assignment to the at least one speaker  5  determined by the assignment determining section  153 , so that the stereo image is formed in the position determined by the stereo image control section  152  (S 33 ). 
     The output control device  1 A carries out the process of S 12  again after the set of processes shown in S 21  to S 23  related to display control and the set of processes shown in S 31  to S 33  related to audio output control have ended or while these sets of processes are carried out. That is, the position and orientation identifying section  11  periodically carries out the process of S 12 . Then, in accordance with the real position and the real orientation updated in S 12 , the process of S 12  and further processes are carried out again. That is, when the real position and the real orientation are updated, the virtual position and the virtual orientation are updated. In response to this, a region included in the virtual space and displayed on each of the displays  4  is updated, and the position of the stereo image formed by the audio outputted from the at least one speaker  5  is updated. 
     By repeating the process of S 12  and subsequent processes in  FIG. 5  in this manner, the output control device  1 A can control, in real time while the moving body  9  is traveling, display of the displays  4  and output of audio from the speakers  5  in accordance with the real position and the real orientation, each of which regularly changes, of the moving body  9 . 
     &lt;&lt;Position of Virtual Audio Source and Position of Stereo Image&gt;&gt; 
       FIG. 6  shows views illustrating a change in relative positional relationship between the moving body  9  and an audio source object in the virtual space and a change in position of a stereo image in the real space. In  FIG. 6 , sections of the moving body  9  are identical to those sections illustrated in  FIG. 3 , and the description thereof will therefore not be repeated. Further, although  FIG. 6  illustrates an example in which two speakers  5  are used to form a stereo image, it is possible to form a stereo image of audio by causing the audio to be outputted from one speaker  5  or from three or more speakers  5 . 
     In  FIG. 6 , for convenience, a positional relationship between the moving body  9  and an audio source object represents a positional relationship in the virtual space, and what is illustrated in the inner space of the moving body  9  represents an event occurring in the real space. Further, it is assumed that time passes in the order of a view at the top, a view in the middle, and a view at the bottom in  FIG. 6 . 
     In a case where it is assumed that the audio source object has moved backward as viewed from the moving body  9  in the virtual space as illustrated in the view at the top and the view in the middle in  FIG. 6 , the stereo image also moves backward similarly. Further, in a case where it is assumed that the audio source object has moved right backward with respect to the moving body  9  as illustrated in the view in the middle and the view at the bottom in  FIG. 6 , the stereo image also moves right backward similarly. 
     As described above, an image containing the audio source object is displayed on a display  4 . As such, by changing a position of the stereo image as illustrated in  FIG. 6 , it is possible to change the position of the stereo image so as to link to a position at which the audio source object is displayed. This enables the passenger P 1  to experience more realistic audio. 
     Note that the audio output control section  15  can control output of audio from each of the speakers  5  so that the greater the distance between the moving body  9  and an audio source object in the virtual space, the smaller a volume in which audio corresponding to the audio source object is outputted. 
     For example, in a case where (i) the audio source setting information  32  is information including a set audio volume of audio data  33  and (ii) the audio source determining section  132  identifies a playback volume of each audio data  33 , the greater a distance from the virtual position of the moving body  9  to an audio source object, the smaller a playback volume in which the audio data  33  is played back by the playback section  151 . As such, the audio output control section  15  can reduce an actual volume of audio outputted from each of the speakers  5  without changing an amount of amplification of an audio volume of each of the speakers  5 . 
     Further, for example, the audio output control section  15  can obtain, from the audio source determining section  132 , information indicative of a distance from the virtual position of the moving body  9  to an audio source object. Then, the audio output control section  15  can control each of the speakers  5  so that the greater the distance, the smaller a volume in which audio corresponding to the audio source object is outputted. 
     This enables a positional relationship between the moving body  9  in the real space and an audio source object in the virtual space to be represented not only by the position of a stereo image but also by a volume of a sound. This enables a passenger to experience more realistic audio. 
     Note that the stereo image control section  152  can add an effect to audio outputted from each of the speakers  5  so that the greater a distance between the moving body  9  and an audio source object in the virtual space, the lower a pitch of audio corresponding to the audio source object. This makes it possible to, for example, reproduce an audio effect of a siren of an ambulance or the like. This enables a passenger to experience more realistic audio. 
     Embodiment 2 
     An output control device in accordance with an aspect of the present disclosure can control an operation of a vibrating element in accordance with audio output. The following description will discuss Embodiment 2 of the present disclosure with reference to  FIGS. 7 and 8 . For convenience, members which are identical in function to the members described in Embodiment 1 will be given identical reference signs, and descriptions of those members will not be repeated. The same also applies to the subsequent embodiments. 
       FIG. 7  is a block diagram illustrating configurations of main parts of the various devices included in the output control system  200  in accordance with Embodiment 2. The output control system  200  differs from the output control system  100  by including a vibrator  6  and an output control device  1 B. Similarly to the output control system  100 , the output control system  200  can include a vehicle interior camera and/or a vehicle interior sensor capable of detecting a position of the head of a passenger. The output control device  1 B can be connected to the vehicle interior camera and/or the vehicle interior sensor. 
     The vibrator  6  is a set of vibrating elements which applies vibration to a passenger P 1 . The output control system  200  can include a plurality of vibrators  6 .  FIG. 8  is a view illustrating an example of how the vibrators  6  are provided in the output control system  200 . As illustrated in  FIG. 8 , the vibrators  6  can be provided, for example, on back surfaces and seating surfaces of seats S 1  and on a floor surface which comes in contact with the feet of the passenger P 1  when the passenger P 1  sits on one of the seats S 1 . 
     The output control device  1 B differs from the output control device  1 A in accordance with Embodiment 1 by including a vibration control section  16 . In the output control device  1 B, when causing speakers  5  to operate, an audio output control section  15  supplies, to the vibration control section  16 , an instruction on operation in accordance with an instruction to the speakers  5 . 
     In accordance with the instruction from the audio output control section  15 , the vibration control section  16  controls an operation of each of the vibrators  6 . For example, the vibration control section  16  controls (i) in which vibrator a vibrating element is caused to vibrate, (ii) in which part of the vibrator the vibrating element is caused to vibrate, and (iii) in what vibration mode the vibrating element is caused to vibrate. Note here that the “vibration mode” refers to an intensity of vibration, an interval of vibrations, a timing of starting vibration, a timing of stopping the vibration, and the like. 
     There is no particular limitation to the instruction provided from the audio output control section  15  to the vibration control section  16 , a timing for providing the instruction, and the control of the vibrators  6  by the vibration control section  16 . For example, the audio output control section  15  can include, in the instruction to the vibration control section  16 , information indicative of a volume of audio outputted from each of the speakers  5 . Then, the vibration control section  16  can determine, in accordance with the volume of audio outputted from each of the speakers  5 , a position at which each of the vibrators  6  vibrates and/or an intensity of vibration of each of the vibrators  6 . 
     For example, in a case where three speakers  5  on the left of the passenger P 1  in  FIG. 8  each have an audio volume set to be greater than those of two speakers  5  in front of the passenger P 1  and three speakers  5  on the right of the passenger P 1 , the vibration control section  16  can cause the left one of the vibrators  6  on the back surfaces of the seats S 1  to vibrate more intensely than the right one of the vibrators  6  on the back surfaces of the seats S 1 . 
     With the above process, when audio data  33  is outputted, it is possible to stimulate the passenger P 1  by vibration caused in accordance with a mode of output of the audio data  33 . For example, in a case where the audio data  33  is a heavy bass sound, an impulsive sound, or the like, applying vibration to the passenger along with output of the audio data  33  makes it possible to more accurately reproduce a phenomenon that would be experienced by a person if such a sound was actually generated. This makes it possible to provide more realistic audio to the passenger P 1 . 
     Embodiment 3 
     In the output control system  100  and the output control system  200 , an image in which a virtual space is drawn is displayed on an entire screen of a display  4 . However, an output control system in accordance with an aspect of the present disclosure can (i) prepare an image in which a virtual space or an object included in the virtual space is interposed on a part of an image captured of a real world and (ii) cause the image to be displayed on a display  4 . That is, an output control system in accordance with an aspect of the present disclosure can be a system which provides a passenger with a virtual experience in an augmented reality (AR) space. 
     In the output control system  100  and the output control system  200 , audio data  33  stored in advance is played back by a speaker  5 . However, an output control system in accordance with an aspect of the present disclosure can cause a speaker  5  to output (i) a sound generated in a real world and (ii) audio data  33  whose stereo image is formed in an adjusted position. The following description will discuss Embodiment 3 of the present disclosure with reference to  FIG. 9 . 
     &lt;&lt;Configuration of Main Parts&gt;&gt; 
       FIG. 9  is a block diagram illustrating configurations of main parts of various devices included in an output control system  300  in accordance with Embodiment 3. The output control system  300  differs from the output control system  100  and the output control system  200  by including a camera  7 , a microphone  8 , and an output control device  1 C. Note that the microphone  8  is not an essential part of the output control system  300 . In a case where a positioning device  2  is a camera, the positioning device  2  can function also as the camera  7 . 
     Note that the output control system  300  can include a vehicle interior camera and/or a vehicle interior sensor capable of detecting a position of the head of a passenger. The output control device  1 C can be connected to the vehicle interior camera and/or the vehicle interior sensor. 
     The camera  7  captures an image of a real space surrounding a moving body  9 . The camera  7  can be a single camera, or a plurality of cameras. It is preferable that the single camera  7  or the plurality of cameras  7  be capable of capturing an image of surroundings of the moving body  9  by 360°. The camera  7  supplies the thus captured image to the output control device  1 C. 
     The microphone  8  is a microphone for obtaining audio generated in a real space surrounding the moving body  9 . The microphone  8  can be a single microphone or a plurality of microphones. It is preferable that the single microphone  8  or the plurality of microphones  8  be capable of obtaining audio of surroundings of the moving body  9  by 360°. The microphone  8  supplies audio data of the audio thus obtained to the output control device  1 C. In Embodiment 3, the “audio generated in a real space surrounding the moving body  9 ” will be hereinafter referred to as “ambient sound” in order to be distinguished from audio data  33 . However, the ambient sound herein can include not only a sound made by a physical object but also all types of sound such as a speech voice of a person. 
     The output control device  1 C obtains the captured image from the camera  7 . The output control device  1 C also obtains the ambient sound from the microphone  8 . A spatial processing section  13  of the output control device  1 C includes a display image preparing section  134 . An audio output control section  15  of the output control device  1 C includes an assignment determining section  153 . 
     The display image preparing section  134  prepares an image to be displayed on each display  4  by synthesizing (i) the captured image from the camera  7  and (ii) an image in which a partial region of a virtual space or a part of an object(s) in the virtual space is drawn. Hereinafter, unless otherwise specified, the display image preparing section  134  carries out a process similar to those carried out by the display image preparing section  133  described in Embodiment 1 and the display image preparing section  133  described in Embodiment 2. 
     The assignment determining section  153  of the audio output control section  15  determines assignment of the ambient sound obtained from the microphone  8  as well as assignment of audio data  33 . In a case where the output control system  300  includes no microphone  8 , the assignment determining section  153  can carry out a processes similar to those carried out by the assignment determining section  153  in accordance with Embodiment 1 and the assignment determining section  153  in accordance with Embodiment 2. 
     In a case where the output control device  1 C is connected to the foregoing vehicle interior camera and/or the vehicle interior sensor, the spatial processing section  13  of the output control device  1 C can identify a position of the head of a passenger on the basis of an image captured by the vehicle interior camera and/or a result of measurement by the vehicle interior sensor. 
     (Preparation of Display Image) 
     The display image preparing section  134  cuts out, from the captured image obtained from the camera  7 , a region to be displayed on each display  4 . It is preferable that the region to be cut out from the captured image be determined by the display image preparing section  134  on the basis of the following (1) to (3). 
     (1) A real position and a real orientation (i.e., a traveling direction) of the moving body  9   
     (2) A position and an orientation of each display  4  in the real space 
     (3) A size and a shape of each display  4   
     In a case where the spatial processing section  13  is capable of identifying a position of the head of a passenger, a region to be cut out from the captured image can be determined by the display image preparing section  134  on the basis of the position of the head of the passenger in addition to the above (1) to (3). 
     (Synthesis of Real Scenery and Scenery in Virtual Space) 
     The display image preparing section  134  prepares an image to be displayed on each display  4  by synthesizing (i) the image cut out from the captured image and (ii) an image of a partial region of the virtual space or a part of an object(s) in the virtual space. This enables the display image preparing section  134  to synthesize scenery in the real space and scenery or an object in the virtual space. In this case, a method for synthesizing the image cut out from the captured image and the image in the virtual space is not particularly limited. Further, there is no particular limitation to a ratio and a layout in which the image cut out from the captured image and the image in the virtual space are displayed. 
     In a specific example, the display image preparing section  134  can cut out from the captured image, for example, a region that would be seen from an inner space of the moving body  9  if each display  4  was a window. Then, an image thus cut out, i.e., an image of real scenery and a certain object in the virtual space can be synthesized, and an image thus obtained can be displayed. 
     By carrying out the above process, the output control system  300  can provide a passenger an illusion in which a part (in the above specific example, the certain object) of a virtual space appears in the real world. That is, the output control system  300  enables a passenger to experience augmented reality (AR). Further, in a case where the output control system  300  includes the microphone  8 , the output control system  300  can output audio for representing a virtual space, together with ambient sound in the real world. Thus, the output control system  300  enables a passenger to experience augmented reality (AR). 
     Variation of Embodiment 3 
     Note that  FIG. 9  illustrates, as an example, the output control system  300  obtained by combining the output control system  100  in accordance with Embodiment 1 with characteristic features of Embodiment 3. However, the output control system  300  can be a system which includes configurations of the output control system  200  in accordance with Embodiment 2 and which carries out also the process described in Embodiment 2. 
     Embodiment 4 
     In each of the above-described Embodiments 1 to 3, the positioning device  2  is a device included in the moving body  9 . However, in each of the output control systems  100 ,  200 , and  300 , the positioning device  2  can be a device provided independently of the moving body  9 . 
     For example, each of the positioning devices  2  described in Embodiments 1 to 3 can be an external camera provided in the vicinity of a road. The external camera captures an image of a moving body  9  traveling on the road. The external camera includes a communication function and is capable of communicating with the output control device  1 A,  1 B, or  1 C. The output control device  1 A,  1 B, or  1 C includes a communication section. The output control device  1 A,  1 B, or  1 C communicates with the external camera in the vicinity of the road via the communication section to obtain the image captured by the external camera. Then, the position and orientation identifying section  11  identifies a real position and a real orientation of the moving body  9  on the basis of the image captured by the external camera and map data  34 . 
     Further, for example, the positioning device  2  can be communication base stations provided in a scattered manner in a real space. In this case, the output control device  1 A,  1 B, or  1 C includes a communication section and communicates with at least three of such communication base stations simultaneously. The position and orientation identifying section  11  identifies a real position of the moving body  9  on the basis of relative positional relationship between the communication base stations and the moving body  9 . The position and orientation identifying section  11  identifies the real position a plurality of times as described above, and identifies a direction in which the real position has changed to be a traveling direction of the moving body  9 , i.e., a real orientation of the moving body  9 . 
     With the above configuration, even in a case where the moving body  9  does not include the positioning device  2 , it is possible to identify a real position of the moving body  9  with use of information obtained from, for example, a monitoring camera, a base station, or the like. This makes it possible to reduce the number of components included in the moving body  9 . 
     Software Implementation Example 
     Control blocks of each of the output control devices  1 A,  1 B, and  1 C can be realized by a logic circuit (hardware) provided in an integrated circuit (IC chip) or the like or can be alternatively realized by software. 
     In the latter case, each of the output control devices  1 A,  1 B, and  1 C includes a computer that executes instructions of a program that is software realizing the foregoing functions. The computer, for example, includes at least one processor and a computer-readable storage medium storing the program. An object of the present disclosure can be achieved by the processor of the computer reading and executing the program stored in the storage medium. Examples of the processor encompass a central processing unit (CPU). Examples of the storage medium encompass a “non-transitory tangible medium” such as a read only memory (ROM), a tape, a disk, a card, a semiconductor memory, and a programmable logic circuit. The computer may further include a random access memory (RAM) or the like in which the program is loaded. Further, the program may be supplied to or made available to the computer via any transmission medium (such as a communication network and a broadcast wave) which allows the program to be transmitted. Note that an aspect of the present disclosure can also be achieved in the form of a computer data signal in which the program is embodied via electronic transmission and which is embedded in a carrier wave. 
     The present disclosure is not limited to the embodiments, but can be altered by a skilled person in the art within the scope of the claims. The present disclosure also encompasses, in its technical scope, any embodiment derived by combining technical means disclosed in differing embodiments. 
     REFERENCE SIGNS LIST 
     
         
           100 ,  200 ,  300 : output control system 
           1 A,  1 B,  1 C: output control device 
           2 : positioning device 
           3 : storage device 
           4 : display 
           5 : speaker 
           6 : vibrator 
           7 : camera 
           8 : microphone 
           9 : moving body 
           11 : position and orientation identifying section 
           12 : reading section 
           13 : spatial processing section 
           131 : virtual position determining section 
           132 : audio source determining section 
           133 ,  134 : display image preparing section 
           14 : display control section 
           15 : audio output control section 
           151 : playback section 
           152 : stereo image control section 
           153 : assignment determining section 
           16 : vibration control section 
           31 : virtual space data 
           32 : audio source setting information 
           33 : audio data 
           34 : map data