Patent Publication Number: US-9851892-B2

Title: Information processing device, recording medium, and information processing method

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is based upon and claims benefit of priority from Japanese Patent Application No. 2015-139338, filed on Jul. 13, 2015, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     An embodiment of the present invention relates an information processing device, a recording medium, and an information processing method. 
     Softphones implemented by application software have been recently gaining widespread use in place of conventional telephones implemented by hardware. Softphones are implemented by software, and it is thus relatively easy, for example, to add functions to the softphones and to make the softphones cooperate with other application software. A variety of applied techniques for softphones are consequently devised. 
     For example, JP 2007-208863A discloses a system including a plurality of cameras each configured to take an overhead view photograph of a floor, and a technique of recognizing the face of a person shown in a captured image acquired from the camera and identifying the person, acquiring the telephone number of the person, and making a telephone call to the person when the person is touched on the display screen of the captured image. 
     SUMMARY 
     However, although JP 2007-208863A certainly describes that the system has a function of switching the plurality of cameras, JP 2007-208863A describes nothing about the specifications of a user interface for an operation of switching the cameras. 
     The following describes a camera switching function of a remote communication support system, and the importance of an operation thereof. 
     A user who makes a telephone call to a call target person at a remote place can learn presence information on the call target person by watching video of the remote place immediately before making a call to the call target person. The presence information shows the situation of the target, and it is preferable that the information be superior in both quality and quantity. The presence information of higher quality allows a user to grasp not only a rough situation like whether or not the call target person is present, but also a more sophisticated situation on the call target person like whether or not the call target person looks busy at present, whether or not the call target person is going to leave the seat, and the like. This consequently facilitates the user who makes a call to speak to the call target person, while the call target person is less frequently spoken to when the call target person does not want to be spoken to in inconvenient situations. Accordingly, this offers useful effects to both of them. 
     To grasp not just a rough situation like whether or not the call target person is present, but a more sophisticated situation as described above (i.e. to see how it goes) in a remote environment effectively, there has to be provided a system function that makes it possible to observe the physical conditions of the call target person from diverse standpoints. It is preferable that the above-described remote communication support system have a plurality of cameras to implement that function, but this is not enough. 
     This is because there is a conventional problem (spatial discontinuities) that if a user switches a plurality of cameras installed at a remote place, the user fails to grasp the positional relationship between the plurality of cameras and gets confused about where the user is watching at present through which camera and which camera the user should select next to watch a desired target/position (Gayer et al., One is not enough: multiple views in a media space, in Proceedings of INTERCHI&#39;93, pp. 335-341). 
     Accordingly, it is desirable to provide a user interface that solves the problem with the positional relationship between the plurality of cameras, and allows a user who makes a call to perform an intuitive and effective operation and to grasp a sophisticated situation of a call target person at a remote place with ease. 
     According to an embodiment of the present invention, there is provided an information processing device including: a position acquisition unit configured to acquire a selection position based on a specification of a user in a captured image obtained by imaging a real space; and a line control unit configured to cause a display unit to display a two-dimensional line obtained by projecting, onto a corresponding position on a display screen of the captured image, a three-dimensional line according to a three-dimensional selection position corresponding to the selection position in a three-dimensional virtual space and a three-dimensional installation position of an imaging device including the three-dimensional selection position within an imaging range. 
     The line control unit may compute the two-dimensional line by projecting the three-dimensional line according to the three-dimensional installation position and the three-dimensional selection position onto the corresponding position on the display screen. 
     The information processing device may include: a real space information providing unit configured to cause the display unit to display a captured image that is captured by an imaging device corresponding to the two-dimensional line when the two-dimensional line is specified. 
     When a position on the two-dimensional line is further specified as a specification position, the line control unit may compute a zoom ratio on the basis of a positional relationship between both end positions of the two-dimensional line and the specification position, and the real space information providing unit may generate the captured image on the basis of the zoom ratio. 
     The line control unit may perform predetermined transformation processing according to the specification position on the two-dimensional line, and may cause the display unit to display the two-dimensional line on which the transformation processing has been performed. 
     The information processing device may include: a line sorting unit configured to, when a plurality of imaging devices that include the three-dimensional selection position within the imaging ranges are present, sort a three-dimensional line on the basis of an evaluation value of the three-dimensional line of each imaging device, and to cause the display unit to display a two-dimensional line obtained by projecting the sorted three-dimensional line onto the corresponding position on the display screen. 
     The line sorting unit may compute the evaluation value of each three-dimensional line on the basis of a distance between the three-dimensional selection position and the three-dimensional installation position. 
     The line sorting unit may compute the evaluation value of each three-dimensional line on the basis of an angle formed by the three-dimensional line and a horizontal plane in the three-dimensional virtual space. 
     The line sorting unit may compute the evaluation value of each three-dimensional line on the basis of an imaging quality of the imaging device corresponding to the three-dimensional line. 
     The line sorting unit may cause the display unit to display a two-dimensional line obtained by projecting the sorted three-dimensional line onto the corresponding position on the display screen, and may cause the display unit to display a total number of three-dimensional lines. 
     The line sorting unit may acquire the imaging quality of the imaging device by analyzing the captured image that is captured by the imaging device, or may acquire the imaging quality of the imaging device on the basis of information embedded in the captured image that is captured by the imaging device. 
     The line control unit may cause the display unit to display the three-dimensional line corresponding to the imaging device in a display manner according to an imaging quality of the imaging device. 
     The three-dimensional installation position of the imaging device may include a position that allows an interpolation image to be captured, the interpolation image being generated from a captured image of each of a plurality of imaging devices in an interpolative manner. 
     When a part of the three-dimensional line is not projected onto an inside of the captured image, the line control unit does not have to cause the display unit to display a result obtained by projecting the part onto the corresponding position on the display screen. 
     In addition, according to an embodiment of the present invention, there is provided a computer-readable recording medium having a program recorded thereon, the program causing a computer to function as an information processing device including a position acquisition unit configured to acquire a selection position based on a specification of a user in a captured image obtained by imaging a real space, and a line control unit configured to cause a display unit to display a two-dimensional line obtained by projecting, onto a corresponding position on a display screen of the captured image, a three-dimensional line according to a three-dimensional selection position corresponding to the selection position in a three-dimensional virtual space and a three-dimensional installation position of an imaging device including the three-dimensional selection position within an imaging range. 
     In addition, according to an embodiment of the present invention, there is provided an information processing method including: acquiring a selection position based on a specification of a user in a captured image obtained by imaging a real space; and causing a display unit to display a two-dimensional line obtained by projecting, onto a corresponding position on a display screen of the captured image, a three-dimensional line according to a three-dimensional selection position corresponding to the selection position in a three-dimensional virtual space and a three-dimensional installation position of an imaging device including the three-dimensional selection position within an imaging range. 
     According to an embodiment of the present invention as described above, it is possible to develop a novel user interface of a remote communication support system. This solves the problem that a user fails to grasp the positional relationship between a plurality of cameras at a remote place and gets cognitively confused, and allows a user who makes a call to perform an intuitive and effective operation and to learn a sophisticated situation of a call target at the remote place with ease, thereby realizing a more excellent remote communication environment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an explanatory diagram illustrating an example of a schematic configuration of an information processing system according to an embodiment; 
         FIG. 2  is a block diagram illustrating an example of a hardware configuration of a terminal device according to an embodiment; 
         FIG. 3  is a block diagram illustrating an example of a functional configuration of a terminal device according to an embodiment; 
         FIG. 4  is an explanatory diagram for describing an example of a display screen displayed in an overhead view mode; 
         FIG. 5  is an explanatory diagram for describing an example of a display screen displayed in a proximity mode; 
         FIG. 6  is an explanatory diagram for describing a first example of a position specified by a user in a captured proximity image; 
         FIG. 7  is an explanatory diagram for describing a second example of a position specified by a user in a captured proximity image; 
         FIG. 8  is an explanatory diagram for describing a first example of a three-dimensional virtual space corresponding to a center office; 
         FIG. 9  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 8  is selected; 
         FIG. 10  is an explanatory diagram for describing a second example of a three-dimensional virtual space corresponding to a center office; 
         FIG. 11  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 10  is selected; 
         FIG. 12  is an explanatory diagram for describing an example of a display screen displayed in a conversation mode; 
         FIG. 13  is a transition diagram for describing an example in which a display mode transitions; 
         FIG. 14  is an explanatory diagram for describing an example of camera lines in the three-dimensional virtual space corresponding to the center office; 
         FIG. 15  is an explanatory diagram for describing an example of camera lines displayed on a display screen of the terminal device; 
         FIG. 16A  is an explanatory diagram for describing an example in which a touch input is made to specify a position on a camera line and feedback thereto is displayed; 
         FIG. 16B  is an explanatory diagram for describing an example in which a touch input is made to specify a position on a camera line and feedback thereto is displayed; 
         FIG. 16C  is an explanatory diagram for describing an example in which a touch input is made to specify a position on a camera line and feedback thereto is displayed; 
         FIG. 17  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 14  is selected; 
         FIG. 18  is an explanatory diagram for describing an example of a display screen of a terminal device  100  in which there are a plurality of camera lines close to each other; 
         FIG. 19  is a block diagram illustrating an example of a software configuration of a terminal device according to an embodiment; 
         FIG. 20  is a block diagram illustrating an example of a hardware configuration of an information management server according to an embodiment; 
         FIG. 21  is a block diagram illustrating an example of a functional configuration of an information management server according to an embodiment; 
         FIG. 22  is a flowchart illustrating an example of schematic steps of information processing according to an embodiment; 
         FIG. 23  is a flowchart illustrating an example of schematic steps of start processing according to an embodiment; 
         FIG. 24  is a diagram illustrating an example of display obtained by applying a function according to a modification  1  to  FIG. 18 ; and 
         FIG. 25  is a diagram illustrating an example in which high/low qualities of photographed images are drawn in association with ways in which camera line are displayed. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Hereinafter, referring to the appended drawings, preferred embodiments of the present invention will be described in detail. It should be noted that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation thereof is omitted. 
     An embodiment of the present invention will be described below in the order of &lt;1. Schematic Configuration of Information Processing System&gt;, &lt;2. Configuration of Terminal Device&gt;, &lt;3. Configuration of Information Management Server&gt;, &lt;4. Processing Steps&gt;, and &lt;5. Modifications&gt;. 
     &lt;&lt;1. Schematic Configuration of Information Processing System&gt;&gt; 
     First of all, the schematic configuration of an information processing system according to an embodiment of the present invention will be described with reference to  FIG. 1 .  FIG. 1  is an explanatory diagram illustrating an example of a schematic configuration of an information processing system according to the present embodiment.  FIG. 1  illustrates that the information processing system includes, for example, a plurality of bases. The information processing system includes a center office  10  and a satellite office  20  (or a home office  20 ) in this example. The center office  10  is a relatively large-scale office, while the satellite office  20  (or the home office  20 ) is a relatively small-scale office. 
     The information processing system includes a camera  11 , a microphone  13 , a sensor  15 , a media distribution server  17 , an information management server  200 , and a local area network (LAN)  19  in the center office  10 . Meanwhile, the information processing system includes a terminal device  100 , a display  21 , and a LAN  23  in the satellite office  20  (or the home office  20 ). The information processing system further includes a private branch exchange (PBX)  40 . 
     (Camera  11 ) 
     The camera  11  images an area in the direction (i.e. imaging direction) in which the camera  11  faces. The center office  10  has a plurality of cameras  11  installed therein. The installed cameras  11  image a part or the whole of the center office from the respective installation position. The center office is imaged from a variety of positions in this way in the information processing system. Captured images generated through the cameras  11  may be still images or moving images (i.e. video). 
     The cameras  11  can, for example, turn around automatically. Furthermore, the cameras  11  each have, for example, a zoom function. The zoom function may be an optical zoom function or a digital zoom function. 
     The cameras  11  may change their positions. As an example, the cameras  11  may be movable by dollies. In other words, the cameras  11  may be movable along rails. In this case, the cameras  11  may move back and forth under the control of motors that move the cameras  11  along rails. This makes it possible to generate captured images that show a subject imaged from different positions with a single camera  11  alone. 
     The zoom function may be a zoom function performed by changing the position of the camera  11  if the camera  11  can change its position. As an example, the zoom function may be a zoom function performed by using a dolly. For example, the camera  11  may be moved toward a subject to zoom in on the subject, while the camera  11  may be moved in the direction away from the subject to zoom out. Zoom using a dolly does not have to be fine zoom like optical zoom and digital zoom. For example, the camera  11  only has to generate a captured image that shows a subject larger in zooming in, while the camera  11  only has to generate a captured image that shows the subject smaller in zooming out. 
     (Microphone  13 ) 
     The microphone  13  collects sounds around the microphone  13 . The center office  10  has a plurality of microphones  13  installed therein. The installed microphones  13  collect sounds around the respective installation positions in the center office. Sounds are collected at a variety of positions in the center office  10  in this way in the information processing system. 
     (Sensor  15 ) 
     The sensor  15  may include various types of sensor. For example, the sensor  15  includes a seat sensor that determines whether or not a person is sitting on the seat. The seat sensor is installed on each seat, and determines whether or not a person is sitting on each seat. The seat sensor is a sensor that can, for example, detect pressure. 
     (Media Distribution Server  17 ) 
     The media distribution server  17  may distribute media (such as audio and video) to a terminal device in response to a request. 
     (Information Management Server  200 ) 
     The information management server  200  manages various kinds of information used in the information processing system. In other words, the information management server  200  stores and timely updates the various kinds of information. 
     For example, the information management server  200  manages parameters for the camera  11 , the microphone  13 , and the sensor  15 . Specifically, the information management server  200 , for example, stores and updates information such as the installation position, the imaging direction (such as the direction vertical to the lens of the camera), and the zoom ratio of the camera  11  as parameters of the camera  11 . 
     In addition, for example, the information management server  200  manages data of the three-dimensional virtual space corresponding to a real space. The three-dimensional virtual space is, for example, modeled after the center office  10 . There are objects disposed in the three-dimensional virtual space. For example, the objects each correspond to a person. The objects are then disposed at the respective three-dimensional virtual positions in the three-dimensional virtual space, the three-dimensional virtual positions corresponding to the respective seats in the center office  10 . In other words, when a person is sitting on the seat, the object is disposed at the three-dimensional virtual position at which the person is supposed to be. As an example, the object is a cylindrical object. The three-dimensional virtual space will be discussed below. 
     (LAN  19 ) 
     The LAN  19  is a network that connects devices in the center office  10  to each other. In addition, the LAN  19  connects each device in the center office  10  to a device outside the center office  10  via an external network  30 . The external network  30  includes, for example, the Internet. 
     (Terminal Device  100 ) 
     The terminal device  100  is used by a user. For example, the terminal device  100  provides functions to the user for communication such as the telephone and e-mail. The terminal device  100  is a tablet terminal as an example. Additionally, the terminal device  100  may be another device such as a smartphone, a personal computer (PC), and a telephone equipped with a display each of which has a display function and a communication function instead of the tablet terminal. 
     (Display  21 ) 
     The display  21  displays a screen. For example, the display  21  displays a screen including a captured image generated through the camera  11 . This allows a great number of people including a user of the terminal device  100  to watch the inside of the center office via the display  21 . 
     In addition, for example, the display  21  also outputs audio. For example, the display  21  outputs audio collected by the microphone  13 . This allows a great number of people including a user of the terminal device  100  to listen to sounds inside the center office via the display  21 . 
     (LAN  23 ) 
     The LAN  23  is a network that connects devices in the satellite office  20  (or the home office  20 ) to each other. In addition, the LAN  23  connects each device in the satellite office  20  to a device outside the satellite office  20  via an external network  30 . 
     (PBX  40 ) 
     The PBX  40  allows devices to communicate with each other via the external network  30 . The PBX  40  operates, for example, in compliance with the H.323 or session initial protocol (SIP). 
     Specifically, for example, the PBX  40  stores communication identification information (such as telephone numbers) and Internet protocol (IP) addresses in association with each other. The PBX  40  then converts the communication identification information into an IP address in response to a request, and provides the IP address to the requestor. 
     Additionally, the PBX  40  may be connected to the LAN  19  or the LAN  23 . 
     &lt;&lt;2. Configuration of Terminal Device&gt;&gt; 
     Next, an example of the configuration of the terminal device  100  according to the present embodiment will be described with reference to  FIGS. 2 to 19 . 
     &lt;2-1. Hardware Configuration&gt; 
     First of all, an example of the hardware configuration of the terminal device  100  according to the present embodiment will be described with reference to  FIG. 2 .  FIG. 2  is a block diagram illustrating an example of the hardware configuration of the terminal device  100  according to the present embodiment.  FIG. 2  illustrates that the terminal device  100  includes a central processing unit (CPU)  801 , read only memory (ROM)  803 , random access memory (RAM)  805 , a bus  807 , a storage device  809 , a communication interface  811 , a camera  813 , a microphone  815 , a speaker  817 , and a touch panel  820 . 
     The CPU  801  executes various kinds of processing in the terminal device  100 . The ROM  803  stores a program and data that make the CPU  801  execute the processing in the terminal device  100 . Meanwhile, the RAM  805  temporarily stores a program and data when the CPU  801  executes the processing. 
     The bus  807  connects the CPU  801 , the ROM  803 , and the RAM  805  to each other. The bus  807  is further connected to the storage device  809 , the communication interface  811 , the camera  813 , the microphone  815 , the speaker  817 , and the touch panel  820 . The bus  807  includes, for example, some types of bus. The bus  807  includes a high-speed bus that connects the CPU  801 , the ROM  803  and the RAM  805  to each other, and one or more other buses that are lower than the high-speed bus in speed as an example. 
     The storage device  809  stores data that are to be temporarily or permanently saved in the terminal device  100 . For example, the storage device  809  may be a magnetic storage device such as a hard disk, or nonvolatile memory such as electrically erasable and programmable read only memory (EEPROM), flash memory, magnetoresistive random access memory (MRAM), ferroelectric random access memory (FeRAM), and phase change random access memory (PRAM). 
     The communication interface  811  is a communication means included in the terminal device  100 , and communicates with an external device via a network (or directly). The communication interface  811  may be an interface for wireless communication. In this case, the communication interface  811  may include, for example, a communication antenna, an RF circuit, and other communication processing circuits. The communication interface  811  may be an interface for wired communication. In this case, the communication interface  811  may include, for example, a LAN terminal, a transmission circuit, and other communication processing circuits. 
     The camera  813  images a subject. The camera  813  may include, for example, an optical system, an image sensor, and an image processing circuit. 
     The microphone  815  collects sounds around the microphone  815 . The microphone  815  converts the sounds around the microphone  815  into electrical signals, and converts the electrical signals into digital data. 
     The speaker  817  outputs audio. The speaker  817  converts the digital data into electrical signals, and converts the electrical signals into audio. 
     The touch panel  820  includes a touch detection surface  821  and a display surface  823 . 
     The touch detection surface  821  detects a touch position on the touch panel  820 . More specifically, for example, when a user touches the touch panel  820 , the touch detection surface  821  senses the touch, generates electrical signals according to the touch position, and then converts the electrical signals into information on the touch position. The touch detection surface  821  may be made by given touch detection technology such as capacitive touch detection technology, resistive touch detection technology, and optical touch detection technology. 
     An output image (i.e. display screen) from the terminal device  100  is displayed on the display surface  823 . The display surface  823  may be made by using, for example, liquid crystal, organic EL (organic light-emitting diodes: OLEDs), and a cathode ray tube (CRT). 
     &lt;2-2. Functional Configuration&gt; 
     Next, an example of the functional configuration of the terminal device  100  according to the present embodiment will be described.  FIG. 3  is a block diagram illustrating an example of the functional configuration of the terminal device  100  according to the present embodiment.  FIG. 3  illustrates that the terminal device  100  includes a communication unit  110 , an input unit  120 , an imaging unit  130 , a sound collection unit  150 , a display unit  150 , an audio output unit  160 , a storage unit  170 , and a control unit  180 . 
     (Communication Unit  110 ) 
     The communication unit  110  communicates with another device. For example, the communication unit  110  is directly connected to the LAN  23 , and communicates with each device in the satellite office  20 . The communication unit  110  also communicates with each device in the center office  10  via the external network  30  and the LAN  19 . Specifically, for example, the communication unit  110  communicates with the camera  11 , the microphone  13 , the sensor  15 , the media distribution server  17 , and the information management server  200 . Additionally, the communication unit  110  may be implemented, for example, by the communication interface  811 . 
     (Input Unit  120 ) 
     The input unit  120  receives an input made by a user of the terminal device  100 . The input unit  120  then provides a result of the input to the control unit  180 . 
     For example, the input unit  120  detects a position specified by the user on the display screen. More specifically, for example, the input unit  120  is implemented by the touch detection surface  821 , and detects a touch position on the touch panel  820 . The input unit  120  then provides the detected touch position to the control unit  180 . 
     (Imaging Unit  130 ) 
     The imaging unit  130  images a subject. For example, the imaging unit  130  images an area in the front direction of the terminal device  100 . In this case, the imaging unit  130  images a user of the terminal device  100 . The imaging unit  130  provides an imaging result (i.e. captured image) to the control unit  180 . Additionally, the imaging unit  130  may be implemented, for example, by the camera  813 . 
     (Sound Collection Unit  140 ) 
     The sound collection unit  140  collects sounds around the terminal device  100 . For example, the sound collection unit  140  collects the voice of a user of the terminal device  100 . The sound collection unit  140  provides a sound collection result (i.e. audio data) to the control unit  180 . Additionally, the sound collection unit  140  may be implemented, for example, by the microphone  815 . 
     (Display Unit  150 ) 
     An output image (i.e. display screen) from the terminal device  100  is displayed on the display unit  150 . The display unit  150  displays a display screen in accordance with control exerted by the control unit  180 . Additionally, the display unit  150  may be implemented, for example, by the display surface  823 . 
     (Audio Output Unit  160 ) 
     The audio output unit  160  outputs audio from the terminal device  100 . The audio output unit  160  outputs audio in accordance with control exerted by the control unit  180 . Additionally, the audio output unit  160  may be implemented, for example, by the speaker  817 . 
     (Storage Unit  170 ) 
     The storage unit  170  stores a program and data for the operation of the terminal device  100 . Additionally, the storage unit  170  may be implemented, for example, by the storage device  809 . 
     For example, the storage unit  170  stores data of the three-dimensional virtual space corresponding to a real space. Specifically, for example, the information management server  200  stores data of the three-dimensional virtual space corresponding to the center office  10 , and then the control unit  180  acquires the data of the three-dimensional virtual space via the communication unit  110 . The storage unit  170  stores the acquired data of the three-dimensional virtual space. 
     (Control Unit  180 ) 
     The control unit  180  provides a variety of functions of the terminal device  100 . The control unit  180  includes a real space information providing unit  181 , a position acquisition unit  183 , an object selection unit  185 , an ID acquisition unit  187 , a telephone unit  189 , a camera line control unit  191 , and a camera line sorting unit  193 . Additionally, the control unit  180  may be implemented, for example, by the CPU  801 , the ROM  803 , and the RAM  805 . 
     (Real Space Information Providing Unit  181 ) 
     The real space information providing unit  181  provides information on the real space to a user of the terminal device  100 . 
     For example, the real space information providing unit  181  causes the display unit  150  to display a display screen of a captured image showing a real space. More specifically, for example, the captured image is generated through the camera  11  in the real space (center office  10 ). The captured image may be generated by the camera  11  or generated by processing the captured image generated by the camera  11 . The display screen partially or entirely includes the captured image. 
     The real space information providing unit  181  acquires a captured image generated by the camera  11  via the communication unit  110 . The real space information providing unit  181  then generates a display screen including the captured image, and causes the display unit  150  to display the display screen. 
     In addition, the captured image is, for example, generated through a single imaging device selected from a plurality of imaging devices in the real space. More specifically, for example, the captured image is generated through a single camera  11  selected from the plurality of cameras  11  disposed in the center office  10 . The following describes a specific technique by which a user selects a camera  11 . Since a user can select the camera  11 , the user can watch an image captured at a desired position. As discussed below, when a user specifies the position of a captured image, the user can specify the position with a more desired captured image. 
     For example, the display screen includes a captured image according to a display mode. More specifically, for example, the display screen includes a first captured image obtained by imaging a first area of a real space in a first display mode, while the display screen includes a second captured image obtained by imaging a second area narrower than the first area in a second display mode. In other words, the real space information providing unit  181  causes the display unit  150  to display the first captured image in the first display mode, and causes the display unit  150  to display the second captured image in the second display mode. 
     More specifically, for example, the first captured image corresponds to a first zoom ratio. Meanwhile, the second captured image corresponds to a second zoom ratio greater than the first zoom ratio. For example, the real space information providing unit  181  makes a zoom request (request to use optical zoom or digital zoom, or to zoom by changing the position of the imaging device (e.g. to zoom by using a dolly)) to the camera  11  via the communication unit  110 , thereby acquiring a captured image corresponding to the first zoom ratio or a captured image corresponding to the second zoom ratio. Alternatively, the real space information providing unit  181  may use digital zoom for a captured image generated by the camera  11  to generate a captured image corresponding to the first zoom ratio or a captured image corresponding to the second zoom ratio. Additionally, the zoom ratio does not have to take a precise value such as a 1.5-fold magnification and a 2-fold magnification, but only has to directly or indirectly indicate the approximate size of a subject that can be included in the captured image. For example, especially when the position of the camera  11  is changed to zoom (e.g. to zoom in and out by using a dolly), the zoom ratio does not have to take a precise value such as a 1.5-fold magnification and a 2-fold magnification, but only has to directly indicate the approximate size of a subject (e.g. in the form of a parameter indicating the approximate size of the subject) or indirectly indicate the approximate size of the subject (e.g. in the form of the position of the camera  11  on the rail). The captured image corresponding to the first zoom ratio only has to show the subject smaller, while the captured image corresponding to the second zoom ratio greater than the first zoom ratio only has to show the subject larger. 
     As an example, the display screen includes a captured overhead view image generated by the camera  11  through imaging at an X-fold zoom ratio (e.g. X=1) in the overhead view mode, while the display screen includes a captured proximity image generated by the camera  11  through imaging at a Y-fold zoom ratio (Y&gt;X) in the proximity mode. In other words, the captured overhead view image is obtained by imaging a wider area of the center office  10 , while the captured proximity image is obtained by imaging a narrower area of the center office  10 . The following describes a specific example on this point with reference to  FIGS. 4 and 5 . 
     Display Screen Displayed in Overhead View Mode 
       FIG. 4  is an explanatory diagram for describing an example of a display screen displayed in the overhead view mode.  FIG. 4  illustrates a display screen  60  that is displayed in the overhead view mode. The display screen  60  includes a captured overhead view image  61 , a button image  63 , a presence icon  65 , a speech balloon image  67 , and a map image  69 . 
     The captured overhead view image  61  is, for example, a captured image generated by the camera  11  through imaging at an X-fold zoom ratio, where X=1 as an example. In other words, the captured overhead view image  61  is a captured image generated by the camera  11  through imaging with no zoom. 
     For example, when a user specifies the position of the captured overhead view image  61 , the real space information providing unit  181  switches the display mode from the overhead view mode to the proximity mode. More specifically, for example, when a user touches the position of the captured overhead view image  61  and the touch position corresponding to the captured overhead view image  61  is detected, the real space information providing unit  181  switches the display mode from the overhead view mode to the proximity mode. 
     The button image  63  is used for selecting another camera  11 . For example, when a user specifies the position of the button image  63 , the real space information providing unit  181  acquires a captured overhead view image generated by another camera  11  and then causes the display unit  150  to display the captured overhead view image. More specifically, for example, when a user touches the position of the button image  63  and the touch position corresponding to the button image  63  is detected, the real space information providing unit  181  acquires a captured overhead view image generated by another camera  11  and then causes the display unit  150  to display the captured overhead view image. For example, when a user specifies the position of a button image  63 A, the camera  11  positioned on the left side of the current camera  11  is selected. Meanwhile, when a user specifies the position of a button image  63 B, the camera  11  positioned on the right side of the current camera  11  is selected. The real space information providing unit  181  then acquires a captured overhead view image generated by the selected camera  11 , and causes the display unit  150  to display the captured overhead view image. 
     The presence icon  65  indicates the busyness degree of a person shown in the captured overhead view image  61 . For example, the color of the presence icon  65  changes in accordance with the busyness degree of a person. As an example, the presence icon  65  indicates a high busyness degree in red, a medium busyness degree in yellow, and a low busyness degree in blue. As discussed below, it is known in which part of the captured overhead view image  61  the person is supposed to be shown, and it is thus possible to display such an icon. 
     For example, in this way, the display screen  60  includes, for example, information (which will be referred to as “person related information”) related to a person shown in the captured overhead view image  61 . The person related information includes, for example, state information indicating the state of the person. As discussed above, the state information is the presence icon  65  as an example. Additionally, the person related information may include a state history indicating the states of the person at two or more time points. As an example, the state history information may include the history of the busyness degrees of a person shown in the captured overhead view image  61 . In other words, the display screen  60  may display the history of the busyness degrees of a person. The real space information providing unit  181  acquires, for example, person related information or information necessary to display the person related information from the information management server  200  via the communication unit  110 . 
     This person related information allows a user to more accurately grasp the situation of the person. In addition, the state information allows a user to more accurately determine whether or not the user can contact the person. The state history allows a user to grasp not only the momentary state of the person, but also the state of the person over a period of time, and the user can thus further more accurately determine whether or not the user can contact the person. 
     The speech balloon image  67  includes letter information presented by a person shown in the captured overhead view image  61 . The speech balloon image  67  is also an example of the person related information. 
     The map image  69  indicates a map of the center office  10 . The map image  69  further indicates the camera  11  in use with an icon. Especially when the center office  10  has a single camera  11  or a few cameras  11  alone installed therein, the map image  69  may be omitted. 
     Display Screen Displayed in Proximity Mode 
       FIG. 5  is an explanatory diagram for describing an example of a display screen displayed in the proximity mode.  FIG. 5  illustrates a display screen  70  that is displayed in the proximity mode. The display screen  70  includes a captured proximity image  71 , a button image  73 , and a map image  75 . 
     The captured proximity image  71  is, for example, a captured image generated by the camera  11  through imaging at a Y-fold zoom ratio (Y&gt;X), where Y=1.5 as an example. In other words, the captured proximity image  71  is a captured image generated by the camera  11  through imaging at a 1.5-fold zoom ratio. 
     The button image  73  is used for switching the display mode from the proximity mode to the overhead view mode. For example, when a user specifies the position of the button image  73 , the real space information providing unit  181  switches the display mode from the proximity mode to the overhead view mode. More specifically, for example, when a user touches the position of the captured button image  73  and the touch position corresponding to the button image  73  is detected, the real space information providing unit  181  switches the display mode from the proximity mode to the overhead view mode. 
     The map image  75  indicates a map of the center office  10  in the same way as the map image  69  in the overhead view mode. The map image  75  further indicates the camera  11  in use. For example, the icon of a camera in use in the map image  75  is displayed at a more advanced position in the proximity mode to symbolically indicate zoom-in. Similarly to the map image  69  in the overhead view mode, especially when the center office  10  has a single camera  11  or a few cameras  11  alone installed therein, the map image  75  may be omitted. 
     The display screen  70  displayed in the proximity mode may also include person related information such as a presence icon and a speech balloon image. 
     As described above, a captured image obtained by imaging a wider area is displayed in accordance with the display mode, thereby allowing a user to watch the overall situation of a real space and to find out a specific person with ease. A captured image obtained by imaging a narrower area is displayed, thereby allowing a user to specify the position of a specific person more easily. All a user has to do is to switch the display mode, so that nothing but an easy operation is requested from the user. The zoom ratio of a captured image obtained by imaging a wider area is different from the zoom ratio of a captured image obtained by imaging a narrower area, and a user can thus intuitively grasp the relationship between these captured images with ease. Accordingly, even if the display mode is switched, the user can find out a specific person and specify the position of the specific person with ease. 
     Other Real Space Information 
     As described above, the real space information providing unit  181  causes the display unit  150  to display a display screen of a captured image showing a real space, thereby providing visual information on the real space. The real space information providing unit  181  may further provide auditory information on the real space. In other words, the real space information providing unit  181  may cause the audio output unit  160  to output audio of audio data obtained by collecting sounds in the real space. 
     For example, the real space information providing unit  181  selects the microphone  13  near the selected camera  11 . The real space information providing unit  181  then acquires, from the microphone  13  via the communication unit  110 , audio data obtained by collecting sounds in the center office  10 . The real space information providing unit  181  may cause the audio output unit  160  to output audio of the acquired audio data. 
     (Position Acquisition Unit  183 ) 
     The position acquisition unit  183  acquires a position specified by a user in a captured image showing a real space on a display screen of the captured image. More specifically, for example, when the input unit  120  detects a position specified by a user in a captured image showing a real space on a display screen of the captured image, the position acquisition unit  183  acquires the position. The position acquisition unit  183  then provides the position in the captured image to the object selection unit  185 . 
     As an example, if the position acquisition unit  183  acquires a position in the captured proximity image  71 , the position acquisition unit  183  provides the position to the object selection unit  185 . The following describes a specific example on this point with reference to  FIGS. 6 and 7 . 
       FIG. 6  is an explanatory diagram for describing a first example of a position specified by a user in a captured proximity image.  FIG. 6  illustrates the captured proximity image  71  included in a display screen displayed in the proximity mode, and a hand  3  of a user.  FIG. 6  also illustrates a person  77  shown in the captured proximity image  71 . The user touches the position of the person  77  with the hand  3 , thereby specifying the position of the person  77  in the captured proximity image  71 . In this case, the input unit  120  detects the position of the person  77  in the captured proximity image  71 , and the position acquisition unit  183  acquires the position. The input unit  120  then provides the acquired position to the object selection unit  185 . 
       FIG. 7  is an explanatory diagram for describing a second example of a position specified by a user in a captured proximity image.  FIG. 7  illustrates a person  77 A and a person  77 B each of which is shown in the captured proximity image  71 . The user touches the position of the person  77 A with the hand  3 , thereby specifying the position of the person  77 A in the captured proximity image  71 . In this case, the input unit  120  detects the position of the person  77 A in the captured proximity image  71 , and the position acquisition unit  183  acquires the position. The input unit  120  then provides the acquired position to the object selection unit  185 . 
     (Object Selection Unit  185 ) 
     The object selection unit  185  selects an object disposed in the three-dimensional virtual space corresponding to a real space on the basis of a position in a captured image to be acquired. For example, when the position acquisition unit  183  acquires a position specified by a user in a captured image showing a real space on a display screen of the captured image, the object selection unit  185  selects an object disposed in the three-dimensional virtual space corresponding to the real space on the basis of the position. 
     The object is disposed at the three-dimensional virtual position in the three-dimensional virtual space corresponding to the position in the captured image. For example, the captured image is included in a display screen in the second mode (e.g. proximity mode). 
     As an example, when the position acquisition unit  183  acquires a position in a captured proximity image generated by the camera  11 , the object selection unit  185  selects an object corresponding to the position from objects disposed in the three-dimensional virtual space corresponding to the center office  10 . Additionally, the object selection unit  185  acquires, for example, data of the three-dimensional virtual space corresponding to the center office  10  from the storage unit  170 . 
     Example in which Single Object is Disposed 
     The following describes a specific example in which a single object is disposed in a three-dimensional virtual space with reference to  FIGS. 8 and 9 . 
       FIG. 8  is an explanatory diagram for describing a first example of a three-dimensional virtual space corresponding to the center office  10 .  FIG. 8  illustrates a three-dimensional virtual space  90  corresponding to the center office  10 . There is an object  91  disposed in the three-dimensional virtual space  90 . The object  91  corresponds to a person (e.g. Mr. A). The object is disposed at the three-dimensional virtual position corresponding to the position of the seat of the person (e.g. Mr. A) in the center office  10 . In other words, when the person is sitting on the seat, the object  91  is disposed at the three-dimensional virtual position at which the person is supposed to be. The object  91  is a cylindrical object in this example. The cylindrical object has a radius R and a height H. The radius R and the height H are, for example, defined in advance. Additionally, data of the three-dimensional virtual space  90  also include information related to each camera  11 . For example, the information related to each camera  11  includes the three-dimensional virtual position corresponding to the installation position of each camera  11 , the imaging direction (e.g. direction vertical to the lens of the camera), and the field angle. 
       FIG. 9  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 8  is selected.  FIG. 9  illustrates a positional relationship on the horizontal plane in the three-dimensional virtual space  90  for ease of understanding. Specifically,  FIG. 9  illustrates the object  91  disposed in the three-dimensional virtual space  90 , a three-dimensional virtual position (which will be referred to as “virtual camera position”) O corresponding to the installation position of the camera  11  used for capturing an image, an axis y corresponding to the imaging direction (e.g. direction vertical to the lens of the camera) of the camera  11 , and an axis x orthogonal to the axis y. It is assumed in this example for ease of understanding that the camera  11  is installed to have the imaging direction parallel to the horizontal plane. 
       FIG. 9  further illustrates a field angle θ of the camera  11 .  FIG. 9  also illustrates a virtual plane  93  that is vertical to the axis y corresponding to the imaging direction of the camera  11  and has a width corresponding to the field angle θ. The virtual plane  93  is spaced apart from the virtual camera position O by a distance z. The virtual plane  93  is a quadrangular plane, and has the same aspect ratio as the aspect ratio of a captured image. In other words, the virtual plane  93  corresponds to the captured image. 
     The object selection unit  185  converts a position specified by a user in the captured image, for example, as illustrated in  FIG. 6 , into a three-dimensional virtual position A. The object selection unit  185  then identifies an object intersecting the line connecting the virtual camera position O and the three-dimensional virtual position A. The object selection unit  185  identifies the object  91  in this example. The object selection unit  185  then selects the object  91 . 
     For example, when a user specifies, on a captured image, a position in the captured image which is converted into a three-dimensional virtual position between a three-dimensional virtual position B and a three-dimensional virtual position D on the virtual plane  93 , the object  91  is selected in the example of  FIG. 9 . Additionally, the person corresponding to the object  91  is shown at such a position in a captured image, in general. 
     Additionally, the distance z is decided in a manner that the virtual plane  93  is positioned between the virtual camera position O and the object  91 . As an example, the distance z is the focal distance of the camera  11 , but needless to say, the distance z is not limited thereto. 
     The technique has been described for ease of understanding that selects an object on the basis of the horizontal plane of the three-dimensional virtual space  90 , but needless to say, even if the vertical direction (e.g. z axis) is used, it is still possible to convert a position in a captured image into a three-dimensional virtual position and to identify the object  91  on the basis of the three-dimensional virtual position. 
     For example, the object corresponding to a position in a captured image is selected as described above. Although a position in a captured image is converted into a three-dimensional virtual position to identify the object corresponding to the position in the captured image in the above-described example, any other techniques can be used to identify the object corresponding to a position in a captured image. 
     As an example, the object selection unit  185  may use the virtual camera position O as the original for projecting the object  91  onto the virtual plane  93 , and convert the projection range of the object  91  into the range within the captured image. When the range includes the position specified by a user in the captured image, the object selection unit  185  may select the object  91 . 
     As an another example, the object selection unit  185  may render the three-dimensional virtual space  90  by using the virtual camera position O, the axis y, and the field angle θ to generate a rendering image, and obtain the range within the captured image which corresponds to the object  91  from the range in the rendering image within which the object  91  is shown. When the range includes the position specified by a user in the captured image, the object selection unit  185  may select the object  91 . 
     Selection of Object Based on State 
     For example, the object  91  disposed in the three-dimensional virtual space  90  corresponds to state information indicating any of a plurality of states. For example, the object  91  corresponds to a person. The object  91  corresponds to state information (which will be referred to as “presence/absence information”) indicating whether or not the person is sitting on the seat. The presence/absence information indicates a state in which a person is sitting on the seat or a state in which a person is not sitting on the seat. For example, the object selection unit  185  acquires a determination result indicating whether or not the person corresponding to the object  91  is sitting on the seat from the sensor  15  via the communication unit  110 . The determination result then serves as the presence/absence information. 
     For example, the object selection unit  185  selects the object that is disposed in the three-dimensional virtual space and corresponds to the state information indicating a predetermined state of the plurality of states. For example, the object selection unit  185  selects an object that is disposed in the three-dimensional virtual space and corresponds to state information indicating the state in which the person is sitting on the seat. In other words, when the sensor  15  determines that the person is sitting on the seat, the object selection unit  185  can select the object corresponding to the person, but when the sensor  15  determines that the person is not sitting on the seat, the object selection unit  185  does not select the object corresponding to the person. 
     In this way, the selection of an object depends on the state of a person, and it is thus possible to avoid the selection of an object that is not actually to be selected. For example, it is possible to avoid the selection of an object that corresponds to a person who is not present. 
     Example in which Two Objects are Disposed 
     In addition, there may be two or more objects disposed in a three-dimensional virtual space. The following describes a specific example in which two objects are disposed with reference to  FIG. 10 . 
       FIG. 10  is an explanatory diagram for describing a second example of the three-dimensional virtual space corresponding to the center office  10 .  FIG. 10  illustrates the three-dimensional virtual space  90  corresponding to the center office  10 . There are objects  91 A and  91 B disposed in the three-dimensional virtual space  90 . The object  91 A corresponds to a certain person (e.g. Mr. A), and is disposed at the three-dimensional virtual position corresponding to the position of the certain person&#39;s seat in the center office  10 . The object  91 B corresponds to a certain person (e.g. Mr. B), and is disposed at the three-dimensional virtual position corresponding to the position of the certain person&#39;s seat in the center office  10 . Similarly to the example of  FIG. 8 , the object  91  is a cylindrical object having the radius R and the height H. 
     When there are two or more objects disposed in a three-dimensional virtual space in this way, the plurality of objects may correspond to positions specified by a user in a captured image For example, both the objects  91 A and  91 B may correspond to positions specified by a user in a captured image in the example of  FIG. 10 . As an example, when there may be two persons shown in a captured image as illustrated in  FIG. 7 , a user specifies the position in the captured image at which the two persons overlap with each other, and the two objects corresponding to the two persons may then correspond to the positions. 
     Accordingly, in this case (i.e. a plurality of objects correspond to positions specified by a user in a captured image), the object selection unit  185  selects any one of the plurality of objects. In other words, when there are a plurality of objects disposed at the respective three-dimensional virtual positions in the three-dimensional virtual space corresponding to positions specified by a user in a captured image, the object selection unit  185  selects any one of the plurality of objects. 
     For example, the captured image is generated through an imaging device present in the real space. The object selection unit  185  then selects an object nearer to the three-dimensional virtual position in the three-dimensional virtual space corresponding to the imaging device from the plurality of objects. More specifically, for example, the captured image is generated through the camera  11  in the center office  10 . When there are a plurality of objects corresponding to positions specified by a user in a captured image, the object selection unit  185  then selects an object nearer to the three-dimensional virtual position (i.e. virtual camera position O) corresponding to the installation position of the camera  11 . The following describes a specific example on this point with reference to  FIGS. 10 and 11 . 
       FIG. 11  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 10  is selected.  FIG. 11  illustrates a positional relationship on the horizontal plane in the three-dimensional virtual space  90  for ease of understanding. Specifically,  FIG. 11  illustrates the objects  91 A and  91 B disposed in the three-dimensional virtual space  90 . Similarly to  FIG. 9 ,  FIG. 11  illustrates the virtual camera position O, the axis y, the axis x, the field angle θ, and the virtual plane  93 . It is also assumed in this example for ease of understanding, similarly to  FIG. 9 , that the camera  11  is installed to have the imaging direction parallel to the horizontal plane. 
     For example, positions in the captured image are specified by a user as illustrated in  FIG. 7 . In this case, if the specified positions in the captured image are converted into three-dimensional virtual positions between a three-dimensional virtual position B′ and the three-dimensional virtual position D, both the objects  91 A and  91 B are identified as the objects corresponding to the positions in the captured image in accordance with the technique described with reference to  FIG. 9 . The object selection unit  185  then selects, from the objects  91 A and  91 B, the object  91 A nearer to the virtual camera position O. 
     Additionally, if positions specified by a user are converted into the three-dimensional virtual positions between the three-dimensional virtual position B and the three-dimensional virtual position B′, the object  91 A is identified and selected as the object corresponding to the position in the captured image. Additionally, if positions specified by a user are converted into the three-dimensional virtual positions between the three-dimensional virtual position D and the three-dimensional virtual position D′, the object  91 B is identified and selected as the object corresponding to the position in the captured image. 
     If a single object is selected from a plurality of objects in this way, a plurality of objects are not selected, and then it is possible to avoid an error (error caused by the acquisition of a plurality of communication IDs) in the following processing. The selection of the object near the virtual camera position corresponding to the camera  11  from a plurality of objects leads to the selection of the object corresponding to a person shown in the foreground even if, for example, people are overlapping with each other in the captured image. The object corresponding to the person intended by the user is then selected. 
     As described above, the object selection unit  185  selects an object. The object selection unit  185  then provides identification information (which will be referred to as “object ID”) on the selected object to the ID acquisition unit  187 . The object ID may be identification information on the person corresponding to the selected object, or merely a number attached to the selected object. 
     (ID Acquisition Unit  187 ) 
     The ID acquisition unit  187  acquires identification information corresponding to the selected object. For example, the identification information is communication identification information (which will be referred to as “communication ID”) corresponding to the selected object. The communication ID is a telephone number as an example. 
     Specifically, for example, when the object selection unit  185  selects an object, the ID acquisition unit  187  acquires the object ID of the selected object. The object selection unit  185  then transmits the object ID to the information management server  200  via the communication unit  110 , and acquires the communication ID corresponding to the object ID. The communication ID is the communication ID of the person corresponding to the selected object. 
     For example, as described above, the ID acquisition unit  187  acquires the communication ID corresponding to the selected object. The communication ID is the communication ID of a communication device of the person (i.e. person shown at a position specified by a user in a captured image) corresponding to the object. The ID acquisition unit  187  then provides the acquired communication ID to the telephone unit  189 . 
     As described above, when a user specifies a position in a captured image, the object corresponding to the position is selected and the communication ID corresponding to the object is acquired. This allows the user to contact the target person with an intuitive operation. Since the object corresponding to a person is selected and the communication ID is acquired irrespective of the way the person is shown in a captured image, the user can more surely contact the person. 
     (Telephone Unit  189 ) 
     The telephone unit  189  provides a function for making a telephone call. For example, the telephone unit  189  provides the function of a softphone. 
     For example, when the telephone unit  189  acquires a communication ID provided by the ID acquisition unit  187 , the telephone unit  189  uses the communication ID to make a telephone call. More specifically, for example, when the telephone unit  189  acquires a communication ID, the telephone unit  189  provides the communication ID to the PBX  40  via the communication unit  110  and acquires the IP address from the PBX  40 . The telephone unit  189  then executes a series of sequences for establishing a session with the communication device (i.e. communication device serving as a telephone call receiver) having the IP address. 
     The telephone unit  189  makes a telephone call to call the person shown at a position specified by a user in a captured image on a display screen in this way. In other words, the telephone unit  189  makes a telephone call to the communication device of the person. 
     When the communication unit  110  receives audio data from the communication device of the person on the other side of the telephone, the telephone unit  189  causes the audio output unit  160  to output the audio of the audio data. In addition, the telephone unit  189  causes the communication unit  110  to transmit audio data provided by the sound collection unit  140  to the communication device of the person on the other side of the telephone. The telephone unit  189 , for example, causes the communication unit  110  to transmit a captured image (such as a captured image showing a user of the terminal device  100 ) provided by the imaging unit  130  to the communication device of the person on the other side of the telephone. 
     The telephone unit  189  causes the display unit  150  to display a display screen for a telephone call. For example, a display mode in which a display screen for a telephone call is displayed is referred to as conversation mode. In this case, when the telephone unit  189  acquires the communication ID provided by the ID acquisition unit  187 , the telephone unit  189  switches the display mode from the proximity mode to the conversation mode. The following describes a specific example with reference to  FIG. 12  about the display screen in the conversation mode. 
       FIG. 12  is an explanatory diagram for describing an example of a display screen displayed in the conversation mode.  FIG. 12  illustrates a display screen  80  that is displayed in the conversation mode. The display screen  80  includes a captured image  81  of the other side of the line, a button image  83 , and a captured image  85  of the side of the terminal device  100 . 
     The captured image  81  of the other side of the line is, for example, a captured image acquired from the communication device of the person on the other side of the telephone. For example, when the communication unit  110  receives a captured image from the communication device of the person on the other side of the telephone, the telephone unit  189  uses the captured image as the captured image  81  of the other side of the line. 
     Meanwhile, the button image  63  is an image for hanging up the telephone. For example, when a user specifies the position of the button image  83 , the telephone unit  189  hangs up the telephone. More specifically, for example, when a user touches the position of the button image  83  and the touch position corresponding to the button image  83  is detected, the telephone unit  189  executes a sequence for hanging up the telephone, the sequence including the disconnection of the session. In addition, for example, the telephone unit  189  switches the display mode from the conversation mode to the overhead view mode. 
     The captured image  85  of the side of the terminal device  100  is a captured image provided by the imaging unit  130 . 
     (Others: Transition of Display Mode) 
     The following describes a specific example of the transition between the overhead view mode, the proximity mode, and the conversation mode with reference to  FIG. 13 . 
       FIG. 13  is a transition diagram for describing an example in which a display mode transitions.  FIG. 13  illustrates that, for example, processing of connecting the camera  11 , the microphone  13 , the sensor  15 , and the information management server  200  at the start of software causes the display mode to transition to an overhead view mode  301  (ENTRY). 
     Overhead view mode processing is executed in the overhead view mode  301  (DO). When a user specifies the position of the captured overhead view image  61 , mode change processing is executed (EXIT) and the display mode switches from the overhead view mode  301  to a proximity mode  303 . The mode change processing includes zoom processing of the camera  11  (ENTRY). 
     Proximity mode processing is executed in the proximity mode  303  (DO). When a user specifies the position of the captured proximity image  71  which shows a person, mode change processing is executed (EXIT) and the display mode switches from the proximity mode  303  to a conversation mode  305 . The mode change processing in this case includes processing of a telephone call (ENTRY). When a user specifies the position of the button image  73 , mode change processing is executed (EXIT) and the display mode switches from the proximity mode  303  to the overhead view mode  301 . The mode change processing in this case includes the connection processing (ENTRY). 
     Conversation mode processing is executed in the conversation mode  305  (DO). When a user specifies the position of the button image  83 , mode change processing is executed (EXIT) and the display mode switches from the conversation mode  305  to the overhead view mode  301 . The mode change processing in this case includes the connection processing (ENTRY). 
     (Others: Another Example of Display Screen) 
     Captured Image according to Display Mode 
     As discussed above, for example, the real space information providing unit  181  causes the display unit  150  to display a first captured image (such as a captured overhead view image) obtained by imaging a first area of a real space in the first display mode (such as the overhead view mode). Meanwhile, the real space information providing unit  181  causes the display unit  150  to display a second captured image (such as a captured proximity image) obtained by imaging a second area narrower than the first area in the second display mode (such as the proximity mode). In the above-described example, the first captured image obtained by imaging the first area of the real space, in particular, corresponds to a first zoom ratio, while the second captured image obtained by imaging the second area narrower than the first area corresponds to a second zoom ratio higher than the first zoom ratio. However, the first and second captured images are not limited thereto. 
     For example, the first captured image may be generated through a first imaging device of a plurality of imaging devices present in the real space, while the second captured image may be generated through a second imaging device of the plurality of imaging devices. In this case, for example, the real space information providing unit  181  selects a camera  11  that images a wide area of the center office  10  in the overhead view mode, and acquires a captured image generated by the camera  11  as a captured overhead view image. The real space information providing unit  181  selects a camera  11  (such as a camera positioned more forward) that images a narrower area of the center office  10  in the proximity mode, and acquires a captured image generated by the camera  11  as a captured proximity image. 
     Accordingly, some disposition of the camera  11  facilitates a user to more easily specify the position of a person. There is no need to request the camera  11  to zoom. Accordingly, there is no contention of requests from individual terminal devices that request, for example, optical zoom or zoom using a dolly, so that none of the terminal devices have to be waiting. There is also no increase in processing loads as digital zoom requests. 
     Captured Image Generated through Imaging Under More Free Condition 
     An example in which the display mode is switched has been described as the above-described example, but the display screen is not limited thereto. For example, a captured image may be generated through imaging under a more free condition, and a display screen including the captured image may be displayed instead of the switch of the display mode. 
     For example, a captured image of a real space may correspond to a zoom ratio selected from a plurality of zoom ratios. In this case, for example, the real space information providing unit  181  requests a zoom ratio specified by a user via the input unit  120  from the camera  11  via the communication unit  110 . As a result, the camera  11  changes the zoom ratio in accordance with the request, and provides the terminal device  100  with a captured image generated through imaging at the changed zoom ratio. The real space information providing unit  181  causes the display unit  150  to display a display screen including the provided captured image. When a user specifies a position in the captured image, the position acquisition unit  183  acquires the position. The position acquisition unit  183  then provides the position in the captured image to the object selection unit  185 . 
     This allows a user to specify a zoom ratio minutely, and then, a desired captured image can be displayed. The user can thus specify the position of a specific person more easily. 
     Additionally, as discussed above, the zoom ratio does not have to take a precise value such as a 1.5-fold magnification and a 2-fold magnification, but only has to directly or indirectly indicate the approximate size of a subject that can be included in the captured image. For example, especially when the position of the camera  11  is changed to zoom (e.g. to zoom in and out by using a dolly), the zoom ratio does not have to take a precise value such as a 1.5-fold magnification and a 2-fold magnification, but only has to directly indicate the approximate size of a subject (e.g. in the form of a parameter indicating the approximate size of the subject) or indirectly indicate the approximate size of the subject (e.g. in the form of the position of the camera  11  on the rail). 
     (Camera Line Control Unit  191 ) 
     The camera line control unit  191  performs operations of calculating various parameters related to a camera line discussed below and camera line display control, and acquires a user input into the camera line. The “camera line” here is a coined word in an embodiment of the present invention, and means a line indicating a display element and an input element of a user interface which are displayed on a display screen of the terminal device  100 . 
     More specifically, as described above, the position acquisition unit  183  acquires a selection position based on specifications of a user, but the camera line may be a line (which will also be referred to as “three-dimensional line”) according to the three-dimensional selection position corresponding to the selection position in the three-dimensional virtual space  90  corresponding to the center office  10  and the three-dimensional installation position of the camera  11  which includes the three-dimensional selection position within the imaging range (discussed below with reference to  FIG. 14 ). The following description uses the position of the object which corresponds to a position specified by a user as an example of the selection position based on specifications of a user, but the position specified by a user may also serve as the selection position based on specifications of a user. 
     The present embodiment uses a straight line as an example of the “line,” but a curved line can also be used as the “line.” For example, a line according to a three-dimensional selection position and a three-dimensional installation position may be the whole of a line having the selection position and the installation position as the respective ends, or may be a part of a line having the selection position and the installation position as the respective ends. The “camera line” may also mean a line (two-dimensional line) obtained by projecting a three-dimensional line onto the corresponding position on a display screen of a captured image in the following description. 
     Additionally, as discussed above, data of the three-dimensional virtual space  90  also include information related to each camera  11 . For example, the information related to each camera  11  includes the three-dimensional virtual position corresponding to the installation position of each camera  11 , the imaging direction (e.g. direction vertical to the lens of the camera, which includes an optical axis), and the field angle (or the imaging range). The terminal device  100  can identify which camera  11  includes a three-dimensional selection position within the imaging range by using the information. The information is stored in the information management server  200 , and when there occurs a situation in which the terminal device  100  requires the information, the information may be acquired via the communication unit  110  as necessary. 
     The camera line is projected and superimposed on a display screen of the terminal device  100  such as the captured overhead view image  61  and the map image  69  of  FIG. 4  (discussed below with reference to  FIG. 15 ). A user of the terminal device  100  watches camera lines displayed on a display screen, and then can intuitively learn whether or not there is a camera capable of imaging a three-dimensional selection position from a different angle from the angle of the camera capturing the captured image that the user is currently watching. If any, the user of the terminal device  100  can also intuitively learn what positional relationship the camera capturing the captured image that the user is currently watching and the three-dimensional selection position have. 
       FIG. 14  is an explanatory diagram for describing an example of camera lines in the three-dimensional virtual space corresponding to the center office  10 . 
       FIG. 14  illustrates the three-dimensional virtual space  90  corresponding to the center office  10 . There are objects  91 A and  91 B disposed in the three-dimensional virtual space  90 . The object  91 A corresponds to a certain person (e.g. Mr. A), and is disposed at the three-dimensional virtual position corresponding to the position of the certain person&#39;s seat in the center office  10 . The object  91 B corresponds to a certain person (e.g. Mr. B), and is disposed at the three-dimensional virtual position corresponding to the position of the certain person&#39;s seat in the center office  10 . Similarly to the example of  FIGS. 8 and 9 , the object  91  is a cylindrical object having the radius R and the height H.  FIG. 14  also illustrates the three-dimensional centroids  92 A and  92 B of the objects  91 A and  91 B, respectively. 
     Furthermore, there are virtual cameras  93 C,  93 D, and  93 E disposed in the three-dimensional virtual space  90 , and the respective virtual camera positions (such as the central positions of the virtual cameras)  94 C,  94 D, and  94 E are also illustrated.  FIG. 14  illustrates line segments having the three-dimensional centroid  92 A of the object  91 A and the virtual camera positions  94 C,  94 D, and  94 E as the respective ends (i.e. camera lines  95 C,  95 D, and  95 E).  FIG. 14  also illustrates a camera line  95 F having the three-dimensional centroid  92 B of the object  91 B and the virtual camera position  94 C as the respective ends just for reference. The object  91 B is not included within the imaging ranges of the virtual cameras  93 C and  93 E, but within only the imaging range of the virtual camera  93 D in this example. Accordingly, there is only one camera line for the object  91 B. 
       FIG. 15  is an explanatory diagram for describing an example of camera lines displayed on a display screen of the terminal device  100 . 
       FIG. 15  illustrates the display screen  80  displayed in the overhead view mode or the proximity mode. The display screen  80  includes a captured image  81 , a map image  84 , and projected and superimposed camera lines  87 C,  87 D,  87 E,  86 C,  86 D, and  86 E. Additionally, there is a toroidal mark superimposed around the picture of the person corresponding to the object according to a position specified in the captured image  81 , and this mark results from feedback to an operation of a user to indicate which object corresponds to the specified position on the screen. 
     The captured image  81  is the same kind of image as the captured overhead view image  61  and the captured proximity image  71 . The map image  84  is the same kind of image as the map image  69  and the map image  75 . In other words, a camera line can be displayed in both the overhead view mode and the proximity mode. 
     The camera line  87  is superimposed close to an image of an object by an operation of a user to specify the image of the object (e.g. operation of touching the position of the object) in the captured image  81 . When the object is specified on the map image  84 , the camera line  86  is superimposed. A camera line drawn on the display screen  80  here is a line obtained by projecting a camera line in the three-dimensional virtual space  90  corresponding to the center office  10  onto the two-dimensional plane of the captured image  81  or the map image  84 , and the two-dimensional line segment having an object shown in the captured image  81  and the camera as the respective ends serves as a drawing element. 
     Additionally, at least one of the camera and the object does not necessarily have to be projected into the captured image  81 . A part of the three-dimensional line that is not projected into the captured image  81  may be then drawn to stick out from the captured image  81  or does not also have to be drawn. Even if a part of the three-dimensional line that is not projected into the captured image  81  is not drawn, a user can roughly grasp the position of the camera or the object corresponding to the camera line by estimating the extending direction of the line segment drawn in the captured image  81 . 
     Additionally, at least one of the camera and the object does not necessarily have to be projected into the display screen  80 . A part of the three-dimensional line that is not projected into the display screen  80  then does not have to be drawn. Even if a part of the three-dimensional line that is not projected into the display screen  80  is not drawn, a user can roughly grasp the position of the camera or the object corresponding to the camera line by estimating the extending direction of the line segment drawn in the display screen  80 . 
     Furthermore, a camera line may serve as not only a display element, but also an input element. An operation of specifying any one of the camera lines by touch thus allows a user to specify the camera  11  in the real space which corresponds to the specified and input camera line. The captured image  81  is switched to a captured overhead view image generated by the specified camera  11  in response to the specifying operation. The specifying operation is performed by the real space information providing unit  181  acquiring a captured overhead view image generated by the specified camera  11 , and causing the display unit  150  to display the captured overhead view image. 
     The user can intuitively learn the positional relationship between the specified object and a camera to which the current camera is switched on the basis of the camera line before an operation of switching a camera. The camera line itself functions as a controller of the input operation, thereby enabling an intuitive and easy input method for an operation of switching a camera. 
     For example, a conventional input method for an operation of switching a camera will be considered in which the terminal device  100  includes a camera switching button, and when the button is pushed down, the cameras  11  are switched in order specified by the system. The use of the input method does not allow a user to learn to which camera the current camera is switched until the user watches a captured overhead view image of the switched camera, which frequently leads to problems (spatial discontinuities) that the user fails to learn the positional relationship between the plurality of cameras and is cognitively confused. The input method according to the present embodiment which uses a camera line can improve such a conventional input method for an operation of switching a camera. 
     The camera line further has an advantage with respect to an operation input in addition to the above-described advantages. For example, a user can specify and input the zoom ratio of the switched camera by performing an operation of specifying any one of the camera lines by touch which are displayed after specifying and inputting an object, and then further performing an operation of specifying any position on the specified camera line by touch. 
     For example, if a user specifies an area around the middle of a camera line by touch, the user is considered to have specified a viewpoint position that allows the user to watch an object from the position of the middle point between the object and the camera serving as the ends of a camera line segment, the current camera is switched to the camera corresponding to the specified camera line, and an image from the switched camera is displayed on the captured image  81  as a captured proximity image having a two-fold zoom ratio. Similarly, if a user specifies a position on about a third of a camera line from the object side end point by touch, a captured proximity image that is captured by the camera corresponding to the camera line and has a three-fold zoom ratio is displayed on the captured image  81 . 
     Additionally, as described above, at least one of the camera and the object does not necessarily have to be projected into the captured image  81 . The position of one of the camera side end point and the object side end point of the camera line which is projected to the outside of the captured image  81  may be used to compute a zoom ratio, or may be corrected to the edge of the captured image  81  (e.g. intersection between a camera line of the captured image and the edge of the captured image) and then used to compute a zoom ratio. 
     Additionally, at least one of the camera and the object does not necessarily have to be projected into the display screen  80 . The position of one of the camera side end point and the object side end point of the camera line which is projected to the outside of the display screen  80  may be used to compute a zoom ratio, or may be corrected to the edge of the display screen  80  (e.g. intersection between a camera line in the display screen and the edge of the display screen  80 ) and then used to compute a zoom ratio. 
     Instead of making a plurality of touch inputs, a user can also efficiently make a single integrated touch input in the two types of input method for a camera line (i.e. a touch input for selecting and specifying, from a plurality of camera lines, a camera to which the current camera is switched and a touch input for specifying a zoom ratio for the selected single camera line). 
     For example, a user first pushes down an image area of an object in the captured image  81  with a finger, and then the camera line corresponding to the camera  11  capable of imaging the object is superimposed on the display screen  80 . The user can then input and specify a camera that captures a desired captured image, and input and specify the magnification into the system with a single touch input (drag) by dragging the finger from the position of the object on the screen to a position on a desired camera line without releasing the finger from the display screen or the touch panel  820 , and afterwards, releasing the finger from the touch panel  820 . 
     Three-stepped specification input operations have been conventionally required to specify an object, to specify a desired camera to which the current camera is switched, and to specify the zoom magnification of the camera, but the introduction of the method according to the present embodiment makes it possible to make the inputs with a single touch input in this way, which significantly improves the usability of a user who uses a remote video transmission application having a function of switching a plurality of cameras from the perspective of efficiency. 
       FIGS. 16A to 16C  are explanatory diagrams for describing some examples in which a touch input is made to specify a position on a camera line and feedback thereto is displayed. Each of  FIGS. 16A to 16C  illustrates a camera line displayed on the display screen  80  and a hand of a user who is making a touch input to the camera line. 
     When a user specifies a position on a camera line with a tap input or a drag input, the partial area corresponding to the position on the camera line changes in color or density in the example illustrated in  FIG. 16A , thereby returning feedback information to the user with respect to the specified input position. 
     A user performs an input operation of moving an end point of a camera line (the user performs an input operation of changing the length of the camera line), thereby specifying a position on the camera line by using the end point in the example illustrated in  FIG. 16B . The touch input method used here is preferably drag. Additionally, the maximum length of a camera line that can be specified may be displayed in advance. 
     The example illustrated in  FIG. 16C  is the same as the example of  FIG. 16B  in that a user performs an input operation of changing the length of a camera line, thereby specifying a position on the camera line. However, the length of the camera line is not adjusted by dragging an end point of the camera line, but instead, pressing and holding (long-pressing) an area on the camera line cause the end point to move in accordance with the length of the pressing time in the example illustrated in  FIG. 16C . Additionally, feedback may be displayed that shows a partial area changing its position like  FIG. 16A  in accordance with the length of the pressing time. 
       FIG. 17  is an explanatory diagram for describing an example in which an object disposed in the three-dimensional virtual space illustrated in  FIG. 14  is selected.  FIG. 17  illustrates a positional relationship on the horizontal plane in the three-dimensional virtual space  90  for ease of understanding. Specifically,  FIG. 17  illustrates the object  91 A disposed in the three-dimensional virtual space  90 , the virtual camera position O of the camera  11 A that is currently used for capturing an image, the virtual camera position  94 E of the virtual camera  93 E corresponding to the camera  11 B that serves as a camera to which the current camera is switched, and the camera line  95 E of the camera  11 B. Similarly to  FIG. 9 ,  FIG. 17  illustrates the axis y, the axis x, the field angle θ, and the virtual plane  93 . It is assumed in this example for ease of understanding, similarly to  FIG. 9 , that the camera  11  is installed to have the imaging direction parallel to the horizontal plane. 
     For example, positions in the captured image are specified by a user as illustrated in  FIG. 7 . If the technique described with reference to  FIG. 9  is used in this case, the camera line control unit  191  performs conversion processing of projecting the camera line (camera line  95 E in this example) corresponding to the position in the captured image onto A to E areas on the virtual plane  93 , and causes the display unit  150  to display the camera line. If a user makes a touch input into the A to E areas, the camera line control unit  191  acquires the camera line corresponding to the touch specification and information on the two-dimensional specification position on the camera line via the input unit  120 , and obtains the three-dimensional virtual position corresponding to the two-dimensional specification position through conversion. 
     The obtained three-dimensional virtual position is used as information on a user viewpoint position desired by the user in the three-dimensional virtual space  90 . As discussed above, the terminal device  100  including the camera line control unit  191  performs processing of switching the current camera to the camera  11  corresponding to the user viewpoint position and magnification specification zoom processing on the camera  11 , and performs processing of displaying the captured proximity image corresponding to the captured image  81  on the display unit  150  and processing of displaying a new camera line on the captured proximity image. 
     As described above, the camera line control unit  191  can perform operations of calculating various parameters related to a camera line and camera line display control, and can acquire a user input into the camera line. 
     (Camera Line Sorting Unit  193 ) 
     When there are a plurality of camera lines (e.g. a plurality of camera lines are present close to each other), the camera line sorting unit  193  performs processing of narrowing the plurality of camera lines (present close to each other) down to a single camera line that is the most suitable for the condition and presenting the most suitable camera line to a user in order to solve the problems that there occurs an error in specifying and inputting a camera line drawn on the display screen  80  and it is difficult to specify and input the camera line. 
       FIG. 18  is an explanatory diagram for describing an example of a display screen of the terminal device  100  in which there are a plurality of camera lines close to each other. The following describes processing performed when the camera lines are present close to each other as an example. However, whether or not the camera lines are present close to each other, similar processing may be equally performed in the presence of a plurality of camera lines. 
       FIG. 18  illustrates the captured image  81  displayed in the overhead view mode or the proximity mode.  FIG. 18  illustrates the object corresponding to a position specified by a user, and three superimposed camera lines corresponding thereto. The three camera lines are present at very nearby display positions, and it is thus difficult for a user to select a single desired camera line from the three camera lines and to make a touch input. Accordingly the user possibly selects and inputs an unintended camera line by error in some cases. Before the user can make an input, the user is confronted with the problem that the plurality of camera lines close to each other prevent the user from visually recognizing each of the displayed camera lines. The camera line sorting unit  193  performs information processing of overcoming the above-described situation. 
     Specifically, the camera line sorting unit  193  performs processing of comparing a plurality of camera lines present close to each other in accordance with a camera line evaluation condition discussed below, sorting out the camera line that has been evaluated the most highly as the most suitable camera line, and displaying the single camera line alone on the display screen  80 . 
     The following demonstrates several examples of the comparison processing corresponding to the camera line evaluation condition. 
     A first camera line evaluation condition is the “distance” between the object corresponding to a position specified by a user and the camera  11 . The distance is synonymous with the full length of a camera line, and can be obtained in  FIG. 14  by calculating the full length of the camera line  95 C (or  95 D or  95 E), or the distance between the two points of the three-dimensional positions  92 A and  94 C (or  94 D or  95 E). As a criterion for high/low comparative evaluation, for example, camera lines having larger distance values may be evaluated more highly. This is because, for example, the cameras  11  having the same performance make the field view of the captured image  81  wider with an increase in distance and allows a user to more widely grasp even the situation of an area around a position/object specified by the user, and a longer distance allows a user to select a wider range of zoom ratios and allows a user to more freely decide a viewpoint, so that a user would be enjoy more excellent advantageous effects. 
     A second camera line evaluation condition is the “angle” formed between a camera line and the horizontal plane (floor) in the three-dimensional virtual space  90  corresponding to the center office  10 . The angle can be obtained in  FIG. 14  by calculating the angles of three points  94 C- 92 A- 94 C′ (i.e. angles of the three-dimensional positions  92 A and  94 C, and the point  94 C′ obtained by orthogonally projecting the three-dimensional position  94 C onto the horizontal plane (floor) of the three-dimensional virtual space  90  vertically) on the basis of the cosine theorem or the like. As a criterion for high/low comparative evaluation, for example, camera lines having smaller angle values close to 0 may be evaluated more highly. This is because a smaller angle against the horizontal plane of the floor makes the light ray of a camera line leveler, makes a target person specified by a user look more natural from the interpersonal perspective (while an overhead image of a person captured from a high angle looks like the person is watched from a surveillance camera) and makes the user feel zoom more natural as if the user was walking to the target person (while zooming in on the target person at a high angle makes the user feel unnatural as if the user was gliding through the air), so that the user would enjoy more excellent advantageous effects. 
     A third camera line evaluation condition is the “performance” of the camera  11  corresponding to each camera line, and comes into effect when each of the cameras  11  belongs to a different model and has a different characteristic. The performance means, for example, the hardware performance of a camera. Some examples of the hardware performance will be described in conjunction with a criterion example for high/low comparative evaluation: the number of pixels in an image sensor (more pixels result in higher evaluation), the area of an image sensor (a larger area results in higher evaluation), the field angle of a lens (a wider field angle results in higher evaluation), the f-number of a lens (a smaller f-number results in higher evaluation), the shutter speed (higher shutter speed results in higher evaluation), the maximum frame rate (a higher frame rate results in higher evaluation), the maximum ISO speed (higher ISO speed results in higher evaluation), the presence/absence of an optical zoom mechanism (a camera having an optical zoom mechanism results in higher evaluation), the photographable distance (a wider range of distance results in higher evaluation), etc. The reason of the criterion for high/low comparative evaluation is that cameras evaluated more highly would more probably provide captured images of higher quality to users. 
     In addition, the camera line sorting unit  193  determines whether or not the plurality of camera lines obtained by the camera line control unit  191  are present close to each other, and whether to perform the sorting processing. Regarding the determination about whether the plurality of camera lines are present close to each other, for example, when the display areas of a plurality of camera lines drawn on the display screen  80  overlap with each other, or the distances between the display areas of the plurality of camera lines are shorter than or equal to a predetermined two-dimensional distance (e.g. the distances are shorter than or equal to 7 mm, or less than or equal to 44 pixels), the camera line sorting unit  193  may determine that the corresponding camera line group are positioned close, and that the sorting processing is to be performed. When the angles formed between a plurality of camera lines in the three-dimensional virtual space  90  are smaller than or equal to a predetermined angle (e.g. smaller than 10 degrees), the camera line sorting unit  193  may determine that the corresponding camera line group are positioned close, and that the sorting processing is to be performed. 
     As described above, the camera line sorting unit  193  can perform processing of comparing a plurality of camera lines present close to each other in accordance with a camera line evaluation condition discussed below, and sorting out the camera line that has been evaluated the most highly as the most suitable camera line. The camera line sorting unit  193  can then perform processing of displaying the single camera line alone on the display screen  80 . 
     &lt;2-3. Software Configuration&gt; 
     Next, an example of the software configuration of the terminal device  100  according to the present embodiment will be described.  FIG. 19  is a block diagram illustrating an example of the software configuration of the terminal device  100  according to the present embodiment.  FIG. 19  illustrates that the terminal device  100  includes an operating system (OS)  840  and application software. The terminal device  100  includes a softphone  851 , a super-presence client  853 , and a telephone call control function  855  as application software. 
     The OS  840  is software that provides a basic function for operating the terminal device  100 . The OS  840  executes application software. 
     The softphone  851  is application software for allowing a user to make a telephone call by using the terminal device  100 . The telephone unit  189  may be implemented, for example, by the softphone  851 . 
     The super-presence client  853  is application software for providing information on a real space to the terminal device  100 . The real space information providing unit  181  may be implemented, for example, by the super-presence client  853 . 
     Additionally, the super-presence client  853  may acquire state information indicating the state of a person in a real space (such as the center office  10 ), and provide the state information to the softphone  851  via the OS  840 . The softphone  851  may then control a telephone call on the basis of the state information. 
     Meanwhile, the telephone call control function  855  is application software that acquires the communication ID of the communication device of a person shown in a captured image in a display screen. The position acquisition unit  183 , the object selection unit  185 , and the ID acquisition unit  187  may be implemented by the telephone call control function  855 . 
     When the telephone call control function  855  acquires the communication ID, the telephone call control function  855  provides the communication ID to the softphone  851  via the OS  840 . The softphone  851  then makes a telephone call by using the communication ID. 
     &lt;&lt;3. Configuration of Information Management Server&gt;&gt; 
     Next, an example of the configuration of the information management server  200  according to the present embodiment will be described with reference to  FIGS. 20 and 21 . 
     &lt;3-1. Hardware Configuration&gt; 
     First of all, an example of the hardware configuration of the information management server  200  according to the present embodiment will be described with reference to  FIG. 20 .  FIG. 20  is a block diagram illustrating an example of the hardware configuration of the information management server  200  according to the present embodiment.  FIG. 20  illustrates that the information management server  200  includes a CPU  901 , ROM  903 , RAM  905 , a bus  907 , a storage device  909 , and a communication interface  911 . 
     The CPU  901  executes various kinds of processing in the information management server  200 . The ROM  903  stores a program and data that make the CPU  901  execute the processing in the information management server  200 . Meanwhile, the RAM  905  temporarily stores a program and data when the CPU  901  executes the processing. 
     The bus  907  connects the CPU  901 , the ROM  903 , and the RAM  905  to each other. The bus  907  is further connected to the storage device  909  and the communication interface  911 . The bus  907  includes, for example, some types of bus. The bus  907  includes a high-speed bus that connects the CPU  901 , the ROM  903  and the RAM  905  to each other, and one or more other buses that are lower than the high-speed bus in speed as an example. 
     The storage device  909  stores data that are to be temporarily or permanently saved in the information management server  200 . The storage device  909  may be a magnetic storage device such as a hard disk, or non-volatile memory such as EEPROM, flash memory, MRAM, FeRAM, and PRAM. 
     The communication interface  911  is a communication means included in the information management server  200 , and communicates with an external device via a network (or directly). The communication interface  911  may be an interface for wireless communication. In this case, the communication interface  811  may include, for example, a communication antenna, an RF circuit, and other communication processing circuits. The communication interface  911  may be an interface for wired communication. In this case, the communication interface  911  may include, for example, a LAN terminal, a transmission circuit, and other communication processing circuits. 
     &lt;3-2. Functional Configuration&gt; 
     Next, an example of the functional configuration of the information management server  200  according to the present embodiment will be described.  FIG. 21  is a block diagram illustrating an example of the functional configuration of the information management server  200  according to the present embodiment.  FIG. 21  illustrates that the information management server  200  includes a communication unit  210 , a storage unit  220 , and a control unit  230 . 
     (Communication Unit  210 ) 
     The communication unit  210  communicates with another device. For example, the communication unit  210  is directly connected to the LAN  19 , and communicates with each device in the center office  10 . Specifically, for example, the communication unit  210  communicates with the camera  11 , the microphone  13 , the sensor  15 , and the media distribution server  17 . The communication unit  210  also communicates with each device in the satellite office  20  via the external network  30  and the LAN  23 . Specifically, for example, the communication unit  210  communicates with the terminal device  100  and the display  21 . Additionally, the communication unit  210  may be implemented, for example, by the communication interface  911 . 
     (Storage Unit  220 ) 
     The storage unit  220  stores a program and data for operating the information management server  200 . 
     The storage unit  220  stores various kinds of information used in the information processing system especially in the present embodiment. 
     As a first example, the storage unit  220  stores parameters for the camera  11 , the microphone  13 , and the sensor  15 . The specific details of the parameters have already been described above. 
     The storage unit  220  stores data of the three-dimensional virtual space corresponding to a real space as a second example. The three-dimensional virtual space is, for example, modeled after the center office  10 . The specific details of the three-dimensional virtual space have already been described above. 
     As a third example, the storage unit  220  stores person related information. The person related information pertains, for example, to a person in the center office  10 . The specific details of the person related information have already been described above. 
     As a fourth example, the storage unit  220  stores the object ID and the communication ID of an object disposed in a three-dimensional virtual space in association with each other. The specific details of the object ID and the communication ID have already been described above. 
     (Control Unit  230 ) 
     The control unit  230  provides a variety of functions of the information management server  200 . 
     For example, the control unit  230  provides various kinds of information used in the information processing system in response to a request. For example, the control unit  230  provides data of a three-dimensional virtual space, person related information, the communication ID corresponding to an object ID, and parameters for the camera  11 , the microphone  13 , and the sensor  15  in response to a request from the terminal device  100 . 
     For example, the control unit  230  updates various kinds of information used in the information processing system as necessary. The control unit  230  updates the information automatically or in accordance with a manual instruction. 
     &lt;&lt;4. Processing Steps&gt;&gt; 
     Next, an example of information processing according to the present embodiment will be described with reference to  FIG. 22 .  FIG. 22  is a flowchart illustrating an example of schematic steps of information processing according to the present embodiment. 
     In step S 401 , the position acquisition unit  183  determines whether or not a user has specified a position in a captured image showing a real space in a display screen of the captured image. More specifically, for example, the position acquisition unit  183  determines whether the user has specified a position in a captured proximity image. If the position has been specified, the processing proceeds to step S 403 . If not, the processing repeats step S 401 . 
     In step S 403 , the position acquisition unit  183  acquires the position specified by the user in the captured image. 
     In step S 405 , the object selection unit  185  acquires data of the three-dimensional virtual space corresponding to the real space from the storage unit  170 . 
     In step S 407 , the object selection unit  185  selects an object disposed in the three-dimensional virtual space on the basis of the acquired position in the captured image. 
     In step S 409 , the camera line control unit  191  acquires information on the camera  11  including the acquired position or the object corresponding to the acquired position within the imaging range. 
     In step S 411 , the camera line control unit  191  calculates and obtains a parameter constituting the camera line corresponding to the camera  11  on the basis of the information on the camera  11  including the acquired position or the object corresponding to the acquired position within the imaging range. 
     In step S 413 , the camera line sorting unit  193  determines whether or not there are a plurality of camera lines close to each other. If there are a plurality of camera lines close to each other, the processing proceeds to step S 415 . If not, the processing proceeds to step S 417 . 
     In step S 415 , the camera line sorting unit  193  performs processing of comparing a plurality of camera lines present close to each other in accordance with the above-described camera line evaluation condition, and sorting out the camera line that has been evaluated the most highly as the most suitable camera line. 
     In step S 417 , the camera line control unit  191  causes the camera line corresponding to the acquired position or the object corresponding to the acquired position to be displayed on the display screen  80 . 
     In step S 419 , the camera line control unit  191  determines whether or not a user has specified one of the camera lines or a position on the camera line. If the camera line or the position has been specified, the processing proceeds to step S 403 . If not, the processing repeats step S 401 . 
     In step S 421 , the camera line control unit  191  acquires a captured image of the camera corresponding to the specified camera line and switches the acquired image and a captured image of the current camera at the specified zoom ratio on the display screen  80 , and then the processing terminates. After the camera is switched, the corresponding camera line may be automatically re-calculated and re-drawn on the display screen. In this case, the processing may be resumed in S 409 . 
     As described above, the information processing according to the present embodiment is executed. Furthermore, an example of start processing executed before the information processing begins will be described with reference to  FIG. 23 . 
       FIG. 23  is a flowchart illustrating an example of schematic steps of start processing according to the present embodiment. 
     In step S 501 , start processing of the softphone  851  is executed. This starts up the softphone  851 . 
     In step S 503 , registration processing of the softphone  851  is executed. For example, as a kind of registration processing of the softphone  851 , registration (such as SIP REGISTRATION) is conducted in the PBX  40 . 
     In step S 505 , start processing of the super-presence client  853  is executed. For example, the camera  11 , the microphone  13 , the sensor  15 , the media distribution server  17 , and the information management server  200  are identified which are used in the super-presence client  853 . 
     In step S 507 , overhead view mode processing of the super-presence client  853  is executed. The series of start processing then terminates. 
     Hereinafter, referring to the appended drawings, preferred embodiments of the present invention will be described in detail. It should be noted that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation thereof is omitted. 
     For example, an example has been described in which the three-dimensional virtual space for a center office is prepared as the three-dimensional virtual space corresponding to a real space, but an embodiment of the present invention is not limited thereto. For example, a plurality of three-dimensional virtual spaces may be prepared. As an example, the three-dimensional virtual space corresponding to a real space may be prepared for each of offices. For example, three-dimensional virtual spaces may also be prepared for satellite offices, home offices, and other center offices. In this case, the three-dimensional virtual space for each office may have a size according to the size of each office. An object selection unit of a terminal device may acquire data of a desired three-dimensional virtual space of three-dimensional virtual spaces. A three-dimensional virtual space may also be prepared for something other than an office. 
     An example has been described in which the object corresponding to a person is selected as long as the person is sitting on the seat, but an embodiment of the present invention is not limited thereto. For example, the object may also be selected even when the person is not sitting on the seat. As an example, when the person is sitting on the seat, the communication ID of the communication device installed at the seat may be acquired, and when the person is not sitting on the seat, the communication ID of the mobile terminal of the person may be acquired. 
     An example has been described in which a communication ID is a telephone number, but an embodiment of the present invention is not limited thereto. The communication ID may be any ID other than a telephone number. As an example, the communication ID may be a softphone ID other than the telephone number. As another example, the communication ID may be an ID for communication other than the telephone. For example, the communication ID may be an e-mail address, or an ID for short messages. In this case, e-mail or a short message may be transmitted with the communication ID. 
     An example has been described in which the communication ID corresponding to an object is acquired when the object is selected, but an embodiment of the present invention is not limited thereto. For example, when an object is selected, any identification information corresponding to the object may be acquired. As an example, when an object is selected, any identification information on the person corresponding to the object may be acquired. For example, the communication ID may be acquired on the basis of the identification information. 
     An example has been described in which an object (object selected by the object selection unit) disposed in the three-dimensional virtual space corresponding to a real space corresponds to a person, and is a cylindrical object, but an embodiment of the present invention is not limited thereto. For example, the object is not a cylindrical object, but may have a different shape. In addition, for example, the object may correspond to something other than a person. As an example, the object may correspond to an area of the real space. Specifically, for example, the object may correspond to a seat, and be disposed at the three-dimensional virtual position corresponding to the position of the seat. The communication ID of the communication device installed at the seat may correspond to the object, and when the object is selected, the communication ID may be acquired. The object may correspond to an area wider than a seat, and cover the three-dimensional virtual range corresponding to the range of the area. The communication ID of the communication device installed in the area may correspond to the object, and when the object is selected, the communication ID may be acquired. 
     An example has been described in which a user specifies the position of a captured image by touch on a display screen, but an embodiment of the present invention is not limited thereto. For example, the position of the captured image may be specified by a user with an input means other than a touch panel. For example, the position of the captured image may be clicked and specified by a mouse, or may be specified by other input means such as a button and a keyboard. 
     An example has been described in which a captured image generated by a camera, audio data generated by a microphone, and a result of a determination made by a sensor are respectively provided directly to a terminal device from the camera, the microphone, and the sensor, but an embodiment of the present invention is not limited thereto. For example, these kinds of data may be provided by another device. As an example, a server (such as a media distribution server) may acquire these kinds of data, and provide the data to the terminal device. 
     An example has been described in which a terminal device has the functions of a position acquisition unit, an object selection unit, an ID acquisition unit, and the like, but an embodiment of the present invention is not limited thereto. For example, these functions may be implemented by a device other than the terminal device. As an example, a server may have these functions. 
     An example has been described in which a terminal device displays a display screen of a captured image of a real space, but an embodiment of the present invention is not limited thereto. For example, the display screen may be displayed by another device. As an example, the display screen may be displayed by a display installed in a satellite office. The position of the captured image included in the display screen may be specified by a user on the display. 
     Processing steps in the information processing described herein do not necessarily have to be performed in the chronological order described in the flowcharts. For example, the processing steps in the information processing may be performed in order different from the order described as the flowcharts, or may be performed in parallel. 
     It is possible to produce a computer program for causing hardware such as a CPU, ROM, and RAM built in an information processing device (such as a terminal device) to execute a function corresponding to each structural element of the information processing device. There is also provided a storage medium having the computer program stored therein. 
     &lt;&lt;5. Modifications&gt;&gt; 
     &lt;5-1. Modification  1 : Notification Function at Time of Camera Line Sorting Processing&gt; 
     As a modification  1 , the camera line sorting unit  193  may have a function of, when the most suitable single camera line is sorted from a plurality of camera line candidates, and the most suitable single camera line alone is displayed, displaying the total number of camera line candidates around the most suitable single camera line.  FIG. 24  is a diagram illustrating an example of display obtained by applying a function according to the modification  1  to  FIG. 18 . For example, when it is determined that there are three camera lines close to each other, and sorting processing is performed on the most suitable single camera line, the camera line sorting unit  193  may display not only the most suitable single camera line on the display screen  80 , but also the number “ 3 ” around the most suitable single camera line on the display screen  80  as illustrated in  FIG. 24 . 
     This function allows a user to instinctively learn whether or not the sorting processing has been performed on the camera lines displayed on the display screen  80  (conversely, it is not possible for a user to learn whether or not the sorting processing has been performed on each camera line without this function). Furthermore, the mode may be switched to cancel the sorting processing and to display all the camera line candidates when the portion on which the total number of camera line candidates is displayed is touched. 
     &lt;5-2. Modification  2 : Acquisition Management Function of Performance Information in Camera Line Evaluation Condition&gt; 
     As a modification  2 , the camera line sorting unit  193  may have a function of, if the above-described camera line evaluation condition is the “performance” of the camera  11 , evaluating the performance, and managing the performance information acquired as a result of the evaluation. For example, the camera line sorting unit  193  may make all the cameras  11  included in the system according to the present embodiment take test photographs for a short period of time, acquire the images, automatically analyze data of each acquired image, and estimate performance information on each camera  11 . Alternatively, the camera line sorting unit  193  may acquire information on the performance from data of the exchangeable image file format (Exif) embedded in a photographed image of each camera  11  even without performing the image analysis processing. 
     The camera line sorting unit  193  may have a crawler program function of automatically crawling through web pages and collecting information, and collecting information on the performance of each camera  11  such as the specifications of the camera from the web pages. The camera line sorting unit  193  may further store and manage data of the performance information acquired as described above in cooperation with the information management server  200 . When the camera line evaluation condition is the performance of the camera  11 , this function reduces the load of a user to manually input and register the performance information on each camera  11  into the system according to the present embodiment. 
     &lt;5-3. Modification  3 : Function of Providing and Displaying Image Quality Related Information onto Camera Line&gt; 
     As a modification  3 , the camera line control unit  191  may have a function of changing the display of the corresponding camera line in accordance with the quality of a captured image of each camera  11 . For example, when the camera C corresponding to the camera line  87 C in the captured image  81  has 320×240 pixels for photography, the camera  11 D corresponding to the camera line  87 D in the captured image  81  has 1920×1200 pixels for photography, and the camera  11 E corresponding to the camera line  87 E in the captured image  81  has 640×480 pixels for photography in  FIG. 15 , a result of the high/low quality comparison between the photographed images shows the camera  11 D&gt;the camera  11 E&gt;the camera  11 C. 
     However, it is not possible for a user to predict such a difference in the image quality before processing of switching the camera. Accordingly, the high/low quality of a photographed image is drawn in association with ways in which the camera lines are displayed as illustrated in  FIG. 25 , thereby allowing a user to intuitively grasp the quality of a photographed image acquired by a camera to which the current camera is switched in selecting a camera line before processing of switching the camera, to select a camera that offers a photographed image of higher quality, and to perform a switching operation. Although the high/low quality of a photographed image is represented by the thickness of a camera line in the example illustrated in  FIG. 25 , the high/low quality of a photographed image may be expressed, for example, by the color or the degree of display transparency of a camera line. 
     &lt;5-4. Modification  4 : Application of Present Technology to Video Interpolation Viewpoint in Free Viewpoint Video&gt; 
     An imaging device chiefly including a hardware entity is intended as a camera to be switched in the present embodiment, but as a modification  4 , the present embodiment can also regard, as one of the cameras  11 , the virtual imaging viewpoint position corresponding to a video interpolation viewpoint generated by the free viewpoint video technology. This makes it possible to apply the present embodiment to a remote video transmission application system that incorporates the free viewpoint video technology, which can switch viewpoints not discretely, but continuously. 
     Additionally, the complete free viewpoint video technology can optionally generate the camera line. In this case, the camera line sorting unit  193  according to the present embodiment may also perform the sorting processing effectively. For example, if the sorting processing is applied to each predetermined spatial range, and the camera line that is the most suitable for the spatial range is obtained, camera lines are narrowed down to the camera lines corresponding to high-quality viewpoint candidates. This probably implements a viewpoint selection input method having higher operability than that of a viewpoint selection input method used when there are infinite possibilities of viewpoint selection operations. 
     Heretofore, preferred embodiments of the present invention have been described in detail with reference to the appended drawings, but the present invention is not limited thereto. It should be understood by those skilled in the art that various changes and alterations may be made without departing from the spirit and scope of the appended claims.