Abstract:
A system includes a first sensor configured to measure a location of a first device, a second sensor configured to measure an orientation of a second device, a display, and a processor. The processor is configured to control the first sensor to start a first measurement, calculate distances between the location of the first device and each of a plurality of installation locations associated with each of a plurality of objects, each of the plurality of objects being arranged virtually at each of a plurality of installation locations in a real space, control the second sensor to start a second measurement when a distribution of the distances indicates that any of the plurality of installation locations of the plurality of objects is included in a given range from the first device, and control the display to display an object according to results of the first measurement and the second measurement.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application 2016-044658, filed on Mar. 8, 2016, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to augmented reality. 
       BACKGROUND 
       [0003]    Recently, an augmented reality (AR) technology has been proposed by which an object is displayed superimposed on a captured image, using a display device such as a head mounted display. When displaying the object superimposed on the image in the AR, the location and the orientation of the head mounted display are detected, and the object is changed according to the detected location and the orientation. The object according to the location and the orientation of the user is thus displayed in the head mounted display superimposed on the captured image. 
         [0004]    The technologies in the related arts are discussed, for example, in Japanese Laid-open Patent Publication No. 2009-294372, Japanese Laid-open Patent Publication No. 2014-235717, and International Publication Pamphlet No. WO2013/145147. 
       SUMMARY 
       [0005]    According to an aspect of the invention, a system includes a first sensor configured to measure a location of a first device, a second sensor configured to measure an orientation of a second device, a display, and a processor. The processor is configured to control the first sensor to start a first measurement of the location, acquire the location from the first sensor, calculate, based on a result of the first measurement, distances between the location of the first device and each of a plurality of installation locations associated with each of a plurality of objects, each of the plurality of objects being arranged virtually at each of a plurality of installation locations in a real space, control the second sensor to start a second measurement of the orientation when a distribution of the distances indicates that any of the plurality of installation locations of the plurality of objects is included in a given range from the first device, acquire the orientation from the second sensor, and control the display to display an object, from among the plurality of objects, according to the result of the first measurement and a result of the second measurement. 
         [0006]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0007]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a block diagram illustrating an example of a configuration of a display control system according to an embodiment; 
           [0009]      FIG. 2  is a diagram illustrating an example of display of object data; 
           [0010]      FIG. 3  is a diagram illustrating an example of a radar chart; 
           [0011]      FIG. 4  is a diagram illustrating another example of display of object data; 
           [0012]      FIG. 5  is a diagram illustrating an example of display when there is no object data to be displayed in a display area; 
           [0013]      FIG. 6  is a diagram illustrating another example of display when there is no object data to be displayed in the display area; 
           [0014]      FIG. 7  is a diagram illustrating an example of an operation related to sensor information when there is no object data to be displayed in the display area; 
           [0015]      FIG. 8  is a diagram illustrating an example of an operation related to sensor information when there is object data to be displayed in the display area; 
           [0016]      FIG. 9  is a diagram illustrating an example of an object data storage unit; 
           [0017]      FIG. 10  is a sequence diagram illustrating an example of display control processing in the embodiment; 
           [0018]      FIG. 11  is the sequence diagram illustrating the example of the display control processing in the embodiment; and 
           [0019]      FIG. 12  is a diagram illustrating an example of a computer that executes a display control program. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0020]    However, when the location and the orientation of the head mounted display are detected, the power consumption increases, and the continuous operating time of the head mounted display is reduced. Therefore, it is difficult to reduce the power consumption by the head mounted display while the head mounted display detects its location and orientation. 
         [0021]    In one aspect, an objective of the technology discussed herein is to reduce the power consumption of a head mounted display. 
         [0022]    Embodiments of a display control method, a communication device, a display control program, and a display control device according to the technology disclosed herein are described below in detail with reference to drawings. Note that the embodiments described herein shall not limit the disclosed technology in any way. In addition, the following embodiments may be combined as appropriate to the extent contradiction does not arise. 
       EMBODIMENTS 
       [0023]      FIG. 1  is a block diagram illustrating an example of a configuration of a display control system according to an embodiment. A display control system  1  illustrated in  FIG. 1  includes a head mounted display (hereinafter also referred to as an “HMD”)  10 , a display control device  100 , and a server  200 . The HMD  10  and the display control device  100  are coupled wirelessly or by wire one-to-one each other. Namely, the HMD  10  functions as an example of a display unit for the display control device  100 . Note that the coupling of the HMD  10  and the display control device  100  is not limited to a one-to-one coupling, and may be a one-to-many, many-to-one, or many-to-many coupling. In addition, in  FIG. 1 , a single pair of the HMD  10  and the display control device  100  is illustrated as an example, but the number of pairs of the HMD  10  and the display control device  100  is not limited, and any given number of pairs of the HMD  10  and the display control device  100  may be included. In addition, the display control device  100  is an example of a communication device. 
         [0024]    The HMD  10  and the display control device  100  are communicably coupled to each other, for example, through a wireless local area network (LAN) such as Wi-Fi Direct (registered trademark). In addition, the display control device  100  and the server  200  are communicably coupled to each other through a network N. Any given type, by wire or wireless, of communication network, such as Internet, a LAN or a virtual private network (VPN) may be employed for such network. 
         [0025]    The HMD  10  is worn by the user together with the display control device  100  displays, and displays a display screen transmitted from the display control device  100 . A monocular transmissive HMD, for example, may be used as the HMD  10 . Note that, various types of HDMs, such as a binocular type or an immersive type, for example, may be used as the HMD  10 . In addition, the HMD  10  includes a location detection sensor and an orientation detection sensor for detecting the location of the user and the orientation of the user&#39;s face. 
         [0026]    The display control device  100  is an information processing device worn and operated by the user, and a mobile communication terminal such as a tablet terminal or a smartphone, for example, may be used as the display control device  100 . The display control device  100  receives from the HMD  10 , for example, information on the location and the orientation detected by the location detection sensor and the orientation detection sensor of the HMD  10 . On detecting object data registered in association with a location which is within an area identified according to the location and the orientation of the HMD  10  detected by the sensors, the display control device  100  displays the object data on the HMD  10 . Note that a location detection sensor included in the display control device  100  may be used instead of the location detection sensor of the HMD  10 . The display control device  100  calculates distance to the location associated with each of the multiple object data. The display control device  100  performs control to suppress detection of the orientation of the HMD  10 , based on distribution of the calculated distances. This thereby enables the display control device  100  to reduce the power consumption of the HMD  10 . 
         [0027]    The server  200  includes a database, for example, in which an AR content for equipment inspection in a certain factory is managed as object data. The server  200  transmits the object data to the display control device  100  through the network N in response to a request from the display control device  100 . 
         [0028]    Description follows regarding an example of a display screen displayed on the HMD  10 .  FIG. 2  is a diagram illustrating an example of display of object data. As illustrated in  FIG. 2 , a radar chart  21 , and AR contents  25  and  26  that are object data are displayed on a display screen  20 . Note that, in the following description, a case in which an AR content is used as an example of object data is explained. On the radar chart  21 , the locations of surrounding object data about the user are displayed. In addition, the radar chart  21  includes a display area  22  and a pre-display area  23 . The object data in the display area  22  are displayed on the display screen  20 . The pre-display area  23  is an area set around the display area  22 . The object data are displayed by dots (points) in the radar chart  21 . 
         [0029]    The object data in the pre-display area  23  are not displayed on the display screen  20  even when the user faces in the direction of the object data, but when the user comes closer to the object data, the object data are displayed on the display screen  20 . In addition, the radar chart  21  includes a view  24  indicating the view of the user. Namely, on the display screen  20 , object data within the display area  22  and the view  24  in the radar chart  21  are displayed. On the display screen  20  illustrated in  FIG. 2 , dots corresponding to the AR contents  25  and  26  are present within the view  24 , and accordingly the AR contents  25  and  26  are displayed on the display screen  20 . 
         [0030]      FIG. 3  is a diagram illustrating an example of the radar chart.  FIG. 3  illustrates the expanded radar chart  21 . The radar chart  21  is configured by a circle centered on the user location  21   a , and includes the display area  22  that is a circle having the radius of a given distance from the user location  21   a  and the pre-display area  23  that is an area interposed by the circle of the display area  22  and a circle larger than the circle of the display area  22 . In addition, an azimuth mark  21   b  indicating the North orientation is displayed on the radar chart  21 . The azimuth mark  21   b  may be moved, for example, according to the movement or the orientation of the user. 
         [0031]    On the display area  22  and the pre-display area  23 , multiple dots, for example, indicating object data are displayed, and for example, object data  27  that is within the display area  22  and also within the view  24 , is displayed on the display screen. On the other hand, object data  28  which is within the pre-display area  23  and within the view  24  is not displayed on the display screen. In addition, object data  29  presented by a dot that is larger than the other dots indicates that the object data is being edited in the display control device  100 . Note that editing of the object data may include, for example, a change in the location, the size, and addition of information, and the like, of the object data. 
         [0032]      FIG. 4  is a diagram illustrating another example of display of object data. As illustrated in  FIG. 4 , a display screen  30  is different from the display screen  20  illustrated in  FIG. 2  with respect to the orientation of the user. Namely, the display screen  30  is a display screen in which the user has changed the direction from facing south to facing northwest. In the radar chart  21  of the display screen  30 , dots corresponding to AR contents  31  and  32  are present within the display area  22  and also within the view  24 . The AR contents  31  and  32  are therefore displayed on the display screen  30 . Note that object data in the pre-display area  23  are not displayed. 
         [0033]      FIG. 5  is a diagram illustrating an example of display when there is no object data to be displayed in a display area. As illustrated in  FIG. 5 , a display screen  35  is a display screen when there is no object data in the surrounding area of the user, namely, the display area  22  and the pre-display area  23 . In the display screen  35 , since there is no object data around the user, no dots indicating object data are displayed either on the radar chart  21 .  FIG. 6  is a diagram illustrating another example of display when there is no object data to be displayed in the display area. As illustrated in  FIG. 6 , a display screen  36  is a screen in which the user has changed the direction from the state in the display screen  35 , but the display screen  36 , including the radar chart  21 , still displays no object data despite the change in the direction, since there is no object data around the user. As such, detection of the orientation of the user is rendered useless when there is no object data around the user, permitting the orientation detection sensor to be suspended as a result. In the embodiment, the power consumption of the HMD  10  is reduced paying attention to this point. 
         [0034]    The display control device  100  controls a sensor information acquisition request to the HMD  10  in order to reduce the power consumption of the HMD  10 .  FIG. 7  is a diagram illustrating an example of an operation related to sensor information when there is no object data to be displayed in the display area. As illustrated in  FIG. 7 , the display control device  100  suspends a sensor information acquisition request to the HMD  10  when there is no object data in the radar chart  21 , because detection of the orientation of the HMD  10  is not called for. 
         [0035]      FIG. 8  is a diagram illustrating an example of an operation related to sensor information when there is an object data to be displayed in the display area.  FIG. 8  illustrates, for example, a case in which the user moves from the location in the state of  FIG. 7  to a location at which object data to be displayed are present. As illustrated in  FIG. 8 , the display control device  100  issues a sensor information acquisition request to the HMD  10  in order to detect the orientation of the HMD  10  when there is object data in the radar chart  21 . The display control device  100  controls the sensor information acquisition request to the HMD  10  according to whether object data is present in the radar chart  21  in this manner, thereby enabling the power consumption of the HMD  10  to be reduced. 
         [0036]    Description follows regarding the configuration of the HMD  10 . As illustrated in  FIG. 1 , the HMD  10  includes a communication unit  11 , a location detection sensor  12 , an orientation detection sensor  13 , a display unit  14 , a storage unit  15 , and a control unit  16 . Note that the HMD  10  may include, for example, function units such as various input devices, audio output devices, and the like, in addition to the function units illustrated in  FIG. 1 . 
         [0037]    The communication unit  11  is implemented, for example, by a communication module and the like such as a wireless LAN. The communication unit  11  is, for example, a communication interface that is coupled to the display control device  100  wirelessly by Wi-Fi Direct (a registered trademark), and that is responsible for communication of information with the display control device  100 . The communication unit  11  receives sensor control information and a display screen from the display control device  100 . The communication unit  11  outputs the received sensor control information and display screen to the control unit  16 . On the other hand, the communication unit  11  transmits sensor information input from the control unit  16 , to the display control device  100 . 
         [0038]    The location detection sensor  12  is a sensor that detects the location of the HMD  10 , namely, the location of the user. The location detection sensor  12  is, for example, a global positioning system (GPS) receiver, and generates location information including the longitude, the latitude, and the altitude based on a received GPS signal. The location detection sensor  12  outputs the generated location information to the control unit  16 . In addition, control information is input from the control unit  16  to the location detection sensor  12 , for starting or ending the operation, change a measurement cycle, and the like. The location detection sensor  12  starts and ends the operation, and changes the measurement cycle, and the like, based on the input control information. Note that the location detection sensor  12  may be a sensor compatible with another positioning system. In addition, when the location of the user is measured by the display control device  100 , the location detection sensor  12  may suspend the operation, or may not be provided. 
         [0039]    The orientation detection sensor  13  is a sensor that detects the orientation of the HMD  10 , namely, the orientation of the user. The orientation detection sensor  13  detects the orientation of the user, namely, the direction in which the user faces, for example, using an acceleration sensor, a gyro sensor, and an orientation sensor. A piezoresistive type or a capacitance type three axis acceleration sensor may be used, for example, as the acceleration sensor. A vibration type gyro sensor may be used, for example, as the gyro sensor. A magnetic sensor may be used for example, as the orientation sensor. The orientation detection sensor  13  outputs orientation information including the detected orientation to the control unit  16 . In addition, control information for starting and ending the operation, or changing the measurement cycle, and the like, is input from the control unit  16  to the orientation detection sensor  13 . The orientation detection sensor  13  starts and ends the operation, and changes the measurement cycle, and the like, based on the input control information. 
         [0040]    The display unit  14  is a display device for displaying various information. The display unit  14  corresponds to, for example, a display element of a transmissive HMD in which an image is projected on the half mirror, and the user may see through the outside scenery together with the image. Note that the display unit  14  may be a display element compatible with an immersive type, a video transmission type, a retinal projection type, or the like of HMD. 
         [0041]    The storage unit  15  is implemented, for example, by a storage device of a semiconductor memory element or the like such as a random access memory (RAM) or a flash memory. The storage unit  15  stores information used for the processing in the control unit  16 . 
         [0042]    The control unit  16  is implemented, for example, by a program stored in internal storage device being executed by a central processing unit (CPU), a micro processing unit (MPU), or the like using the RAM as a work area. In addition, the control unit  16  may be implemented, for example, by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The control unit  16  includes a sensor control unit  17  and a display control unit  18 , and implements or executes functions and operations of information processing described below. Note that the internal configuration of the control unit  16  is not limited to the configuration illustrated in  FIG. 1 , and may have another configuration as long as the configuration executes the information processing described later. 
         [0043]    The sensor control unit  17  controls the location detection sensor  12  and the orientation detection sensor  13  based on the sensor control information received from the display control device  100  through the communication unit  11 . For example, when the power to the HMD  10  is applied, the sensor control unit  17  starts transmission and reception service of sensor information. The transmission and reception service executes an operation corresponding to an application programming interface (API) included in the sensor control information received from the display control device  100 , based on the API defined in advance. Operations executed by the transmission and reception service include, for example, controlling sensor operation and changing measurement cycle. 
         [0044]    Examples of the APIs include “getSensorInfo (Boolean isGetSensorInfo)” for controlling the start and the end of the sensor operation. For this API, “getSensorInfo” is the API name and “(Boolean isGetSensorInfo)” is an API argument. Of the API argument, “Boolean” indicates the type of argument and assumes a binary value (“true” or “false”). “isGetSensorInfo” of the API argument is an actual parameter of the API. When using this API from the display control device  100 , for example, setting the API argument “isGetSensorInfo” to “true” starts acquisition of sensor information in the HMD  10 , and transmission of the sensor information to the display control device  100  is started. On the other hand, setting the API argument “isGetSensorInfo” to “false”, ends acquisition of the sensor information in the HMD  10 , and the transmission of the sensor information to the display control device  100  is ended. Put another way, the sensor control information that includes the API with the API argument “isGetSensorInfo” set to “true” is a request to acquire sensor information. Conversely, the sensor control information that includes the API with the API argument “isGetSensorInfo” set to “false” cancels the request to acquire sensor information. 
         [0045]    The sensor control unit  17  outputs control information instructing start of output of one or more out of the location information and the orientation information based on the sensor control information corresponding to an acquisition request of sensor information, to one or more out of the corresponding location detection sensor  12  and corresponding orientation detection sensor  13 . One or more out of the location information and the orientation information starts to be input from one out of the location detection sensor  12  and the orientation detection sensor  13 , to the sensor control unit  17 . The sensor control unit  17  sets one or more out of the location information and the orientation information, which the sensor control unit  17  has started to receive, as the sensor information, and starts transmitting such sensor information to the display control device  100  through the communication unit  11 . Note that the sensor control unit  17  transmits the sensor information that includes one or more out of the location information and the orientation information, for example, at intervals of one second. 
         [0046]    The sensor control unit  17  outputs control information that instructs termination of output of the information to one or more out of the corresponding location detection sensor  12  and orientation detection sensor  13 , based on sensor control information corresponding to a request to cancel acquisition of the sensor information. Note that, the sensor control unit  17  controls corresponding one or more out of the location detection sensor  12  and orientation detection sensor  13 , for example, similarly for sensor control information corresponding to a request or the like to extend an acquisition interval of the sensor information. 
         [0047]    Description follows regarding the orientation information. The orientation information is information indicating the respective rotation angles of the x axis, the y axis, and the z axis of the HMD  10 . The x axis, the y axis, and the z axis respectively correspond to the longitude, the altitude, and the latitude in the world coordinate system. The rotation angle of the x axis is represented by “Pitch”, and is a rotation angle centered on the x axis. The data acquisition range of “Pitch” is “−π/2&lt;=Pitch&lt;=π/2” [rad]. The rotation angle of the y axis is represented by “Azimuth”, and is a rotation angle centered on the y axis. The data acquisition range of “Azimuth” is “−2π&lt;=Azimuth&lt;=2π” [rad]. The rotation angle of the z axis is represented by “Roll”, and is a rotation angle centered on the z axis. The data acquisition range of “Roll” is “−2π&lt;=Roll&lt;=2π” [rad]. 
         [0048]    The display control unit  18  displays through the display unit  14  the display screen received from the display control device  100  via the communication unit  11 . In addition, the display control unit  18  updates the display of the display unit  14  according to an update of the display screen. 
         [0049]    Description follows regarding the configuration of the display control device  100 . As illustrated in  FIG. 1 , the display control device  100  includes a first communication unit  110 , a second communication unit  111 , a display operation unit  112 , a location detection sensor  113 , a storage unit  120 , and a control unit  130 . Note that the display control device  100  may include various function units included in a known computer, for example, various function units such as an input device, an audio output device, and the like, in addition to the function units illustrated in  FIG. 1 . 
         [0050]    The first communication unit  110  is implemented, for example, by a communication module or the like such as a wireless LAN. The first communication unit  110  is, for example, a communication interface that is coupled to the HMD wirelessly by Wi-Fi Direct (a registered trademark), and that is responsible for communication of information with the HMD  10 . The first communication unit  110  receives sensor information from the HMD  10 . The first communication unit  110  outputs the received sensor information to the control unit  130 . In addition, the first communication unit  110  transmits sensor control information and display screen input from the control unit  130 , to the HMD  10 . 
         [0051]    The second communication unit  111  is implemented, for example, by a mobile phone line such as a third generation mobile communication system, a long term evolution (LTE) system and the like, and a communication module or the like such as a wireless LAN. The second communication unit  111  is a communication interface coupled to the server  200  through the network N wirelessly and is responsible for communication of information with the server  200 . The second communication unit  111  transmits a data acquisition instruction input from the control unit  130  to the server  200  through the network N. In addition, the second communication unit  111  receives object data according to the data acquisition instruction from the server  200  through the network N. The second communication unit  111  outputs the received object data to the control unit  130 . 
         [0052]    The display operation unit  112  is a display device for displaying various information and an input device for accepting various operations from the user. For example, the display operation unit  112  is implemented by a liquid crystal display or the like as the display device. In addition, for example, the display operation unit  112  is implemented by a touch panel or the like as the input device. Namely, the display device and the input device are integrated in the display operation unit  112 . The display operation unit  112  outputs an operation input by the user to the control unit  130  as operation information. Note that the display operation unit  112  may display a screen similar to that of the HMD  10  or a screen different from that of the HMD  10 . 
         [0053]    The location detection sensor  113  is a sensor that detects the location of the display control device  100 , namely, the location of the user. The location detection sensor  113  is, for example, a GPS receiver, and generates location information including the longitude, the latitude, and the altitude based on a received GPS signal. The location detection sensor  113  outputs the generated location information to the control unit  130 . Note that the location detection sensor  113  may be a sensor compatible with another positioning system. In addition, when the location of the user is measured by the HMD  10 , the location detection sensor  113  may suspend the operation. 
         [0054]    The storage unit  120  is implemented, for example, by a RAM, a semiconductor memory element such as a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit  120  includes an object data storage unit  121 . In addition, the storage unit  120  stores information used for the processing in the control unit  130 . 
         [0055]    The object data storage unit  121  stores object data acquired from the server  200 .  FIG. 9  is a diagram illustrating an example of the object data storage unit. As illustrated in  FIG. 9 , the object data storage unit  121  includes items of “object identifier (ID)”, “object data”, and “location information”. The object data storage unit  121  stores, for example, each piece of the object data as one record. 
         [0056]    Here, “object ID” is an identifier by which object data, namely, an AR content is identified. “Object data” is information indicating the object data acquired from the server  200 . “Object data” is, for example, a data file that constitutes the object data, namely, the AR content. “Location information” is location information associated with the object data. “Location information” is information indicating the location information in the world coordinate system of the associated object data. 
         [0057]    The control unit  130  is implemented, for example, by a program stored in an internal storage device being executed by the CPU, the MPU, or the like, using the RAM as a work area. In addition, the control unit  130  may be implemented, for example, by an integrated circuit such as the ASIC or the FPGA. The control unit  130  includes a display control unit  131 , a calculation unit  132 , a detection control unit  133 , and a location measurement unit  134 , and implements or executes functions and operations of information processing described below. Note that the internal configuration of the control unit  130  is not limited to the configuration illustrated in  FIG. 1 , and another configuration may be employed as long as the configuration executes the information processing described later. 
         [0058]    The display control unit  131  starts an application using AR middleware. When the application is started, the display control unit  131  starts to transmit a display screen of the application to the HMD  10  through the first communication unit  110 . 
         [0059]    When the application is started, the display control unit  131  transmits a data acquisition instruction to the server  200  through the second communication unit  111  and the network N. When the display control unit  131  receives object data corresponding to the data acquisition instruction from the server  200  through the second communication unit  111  and the network N, the display control unit  131  stores the received object data in the object data storage unit  121 . 
         [0060]    When the application is started, the display control unit  131  generates and starts a transmission and reception service of sensor information. Similarly to the transmission and reception service of the HMD  10 , the transmission and reception service of the display control device  100  operates based on an API defined in advance. The API provides the transmission and reception service of sensor information when the API is called from another function unit. 
         [0061]    When the application is started, the display control unit  131  outputs a positioning start instruction to the location measurement unit  134 . Note that, when the location detection sensor  12  of the HMD  10  is used, the display control unit  131  transmits sensor control information corresponding to an acquisition request of sensor information including the positioning start instruction to the HMD  10  through the first communication unit  110 . 
         [0062]    When the display area  22  and the pre-display area  23  are input from the calculation unit  132 , the display control unit  131  displays the radar chart  21  on the display screen. In addition, when the locations of object data within the display area  22  and the pre-display area  23  are input from the detection control unit  133 , the display control unit  131  displays the input locations of the object data on the display area  22  and the pre-display area  23 . 
         [0063]    When the view  24  is input from the calculation unit  132 , the display control unit  131  displays the input view  24  superimposed on the display area  22  and the pre-display area  23 . In addition, the display control unit  131  displays object data which is within the display area  22  and within the view  24  on the display screen, with reference to the object data storage unit  121 . Put another way, the display control unit  131  transmits to the HMD  10  an image including a given object according to the search for an object based on the location and the orientation received from the HMD  10 . 
         [0064]    Location information corresponding to a start of positioning in the location measurement unit  134 , or location information included in the sensor information received through the first communication unit  110  corresponding to a start of positioning in the HMD  10 , is input to the calculation unit  132 . When the location information is input, the calculation unit  132  sets the display area  22  and the pre-display area  23 , based on the location information of the user and distances corresponding to the display area  22  and the pre-display area  23 , which have been set in advance. Namely, the calculation unit  132  calculates distance between the user and the object data, based on the input location information. Put another way, the calculation unit  132  calculates distances from the user to the locations respectively associated with the multiple object data. The calculation unit  132  outputs the set display area  22  and pre-display area  23  to the display control unit  131  and the detection control unit  133 . 
         [0065]    In addition, orientation information included in the sensor information received through the first communication unit  110  is input to the calculation unit  132 . The calculation unit  132  sets the view  24  of the user, based on the display area  22 , the pre-display area  23 , and the orientation information. The calculation unit  132  outputs the set view  24  to the display control unit  131 . 
         [0066]    When the set display area  22  and the set pre-display area  23  are input from the calculation unit  132 , the detection control unit  133  detects object data located in the display area  22  and the pre-display area  23 , with reference to the object data storage unit  121 . Namely, the detection control unit  133  determines whether or not object data is present in the display area  22  and the pre-display area  23 . Namely, the detection control unit  133  determines whether or not all of the calculated distances between the user and the object data are within the display area  22  or the pre-display area  23 . 
         [0067]    When one or more out of the calculated distances between the user and the object data are within the display area  22  or the pre-display area  23 , the detection control unit  133  transmits an acquisition request of sensor information, corresponding to the orientation information, to the HMD  10  through the first communication unit  110 . In addition, the detection control unit  133  outputs the locations of the object data, within the display area  22  and the pre-display area  23 , to the display control unit  131 . Note that, when the location information is acquired in the HMD  10 , the detection control unit  133  transmits a request to acquire sensor information corresponding to the location information. Namely, the detection control unit  133  transmits a request that the HMD  10  acquires the sensor information corresponding to the location information to be measured at a normal measurement interval. 
         [0068]    When none of the calculated distances between the user and the object data are within the display area  22  or the pre-display area  23 , the detection control unit  133  transmits a request to cancel acquisition of the sensor information, corresponding to the orientation information, to the HMD  10  through the first communication unit  110 . Note that the detection control unit  133  continuously outputs the locations of object data in the display area  22  and the pre-display area  23  to the display control unit  131 . In this case, when no object data is located in the display area  22  and the pre-display area  23 , namely, when the detection control unit  133  transmits a request to cancel acquisition of the sensor information corresponding to the orientation information to the HMD  10 , the detection control unit  133  suspends output of the location of the object data. Note that, when acquiring the location information in the HMD  10 , the detection control unit  133  transmits a request to cancel acquisition of sensor information corresponding to the location information. Namely, the detection control unit  133  transmits to the HMD  10  a request to cancel acquisition of the sensor information corresponding to the location information, such that the measurement interval is lengthened than a normal time, namely, location is measured in a longer measurement cycle. 
         [0069]    Put another way, the detection control unit  133  detects object data registered associated with a location in the area identified according to the location and the orientation of the HMD  10  detected by the sensors. In addition, the detection control unit  133  performs control in which the detection of the orientation of the HMD  10  is suppressed based on a distribution of calculated distances. In addition, when none out of the multiple locations associated with the object data is included in the target area for displaying object data on the HMD  10 , the detection control unit  133  performs control to suppress detection of the orientation of the HMD  10 . In addition, when all of the multiple locations associated with the object data has a distance longer than a specified distance, the detection control unit  133  performs control to suppress detection of the orientation of the HMD  10 . 
         [0070]    In addition, the detection control unit  133  transmits to the HMD  10 , a signal for controlling operation of the sensor included in the HMD  10  or transmission of sensor information, according to a determination result as to whether there is an object associated with a position having a given positional relationship with the location measured by the location measurement unit  134 . In addition, when the determination result indicates an absence of the object, the detection control unit  133  transmits to the HMD  10  a sensor control information for making the cycle longer, compared with the case in which the determination result indicates a presence of the object. The sensor control information for making the cycle longer is a signal for performing one or more out of a control for making the sensor&#39;s detection operation cycle longer and a control for making the cycle of transmission of sensor information longer. 
         [0071]    In addition, the detection control unit  133  determines whether or not there is an object associated with a location having a given positional relationship with the location based on the location of receipt from the HMD  10 . The detection control unit  133  transmits to the HMD  10 , a signal for controlling operation of the location detection sensor  12  and/or the orientation detection sensor  13 , or transmission of sensor information acquired by the location detection sensor  12  and/or the orientation detection sensor  13 , according to the determination result of the presence of the object. 
         [0072]    In addition, the detection control unit  133  transmits a signal instructing the HMD  10  to transmit the orientation detected by the orientation detection sensor  13 , according to the search for an object associated with a location having a given positional relationship with a location based on the location of receipt. 
         [0073]    When a positioning start instruction is input from the display control unit  131 , the location measurement unit  134  instructs the location detection sensor  113  to start the positioning. When location information is input from the location detection sensor  113 , the location measurement unit  134  outputs the input location information to the calculation unit  132 . In addition, in a case in which the application has ended, the location measurement unit  134  instructs the location detection sensor  113  to end the positioning. 
         [0074]    Description follows regarding the operation of the display control system  1  in the embodiment.  FIGS. 10 and 11  are sequence diagrams illustrating an example of the display control processing in the embodiment. 
         [0075]    The display control unit  131  of the display control device  100  starts the application that uses the AR middleware (Step S 1 ). When the application is started, the display control unit  131  starts to transmit the display screen of the application to the HMD  10 . 
         [0076]    When the power to the HMD  10  is applied, the sensor control unit  17  of the HMD  10  starts a transmission and reception service of sensor information (Step S 2 ). The display control unit  18  starts to display the display screen of the application received from the display control device  100  (Step S 3 ). 
         [0077]    When the application is started, the display control unit  131  transmits a data acquisition instruction to the server  200 . When object data corresponding to the data acquisition instruction is received from the server  200 , the display control unit  131  stores the received and acquired object data in the object data storage unit  121  (Step S 4 ). 
         [0078]    In addition, when the application is started, the display control unit  131  generates and starts a transmission and reception service of sensor information (Step S 5 ). In addition, the display control unit  131  outputs a positioning start instruction to the location measurement unit  134 . When the positioning start instruction is input from the display control unit  131 , the location measurement unit  134  instructs the location detection sensor  113  to start the positioning. When the location information is input from the location detection sensor  113 , the location measurement unit  134  outputs the input location information to the calculation unit  132  (Step S 6 ). 
         [0079]    The location information corresponding to the start of positioning in the location measurement unit  134  is input to the calculation unit  132 . When the location information is input, the calculation unit  132  calculates distances between the user and object data based on the input location information (Step S 7 ). Namely, the calculation unit  132  sets the display area  22  and the pre-display area  23 . The calculation unit  132  outputs the set display area  22  and the set pre-display area  23  to the display control unit  131  and the detection control unit  133 . When the display area  22  and the pre-display area  23  are input from the calculation unit  132 , the display control unit  131  displays the radar chart  21  on the display screen. 
         [0080]    When the set display area  22  and the set pre-display area  23  are input from the calculation unit  132 , the detection control unit  133  determines whether all of the distances between the user and the object data are within the display area  22  or the pre-display area  23  (Step S 8 ). When one or more out of the distances between the user and the object data are within the display area  22  or the pre-display area  23  (Step S 8 : Yes), the detection control unit  133  transmits an acquisition request of sensor information corresponding to the orientation information, to the HMD  10  (Step S 9 ). In addition, the detection control unit  133  outputs the locations of the object data in the display area  22  and the pre-display area  23  to the display control unit  131 . In addition, when the locations of the object data in the display area  22  and the pre-display area  23  are input from the detection control unit  133 , the display control unit  131  displays the locations of the object data, which have been input, on the display area  22  and the pre-display area  23 . 
         [0081]    When none of the distances between the user and the object data are within the display area  22  or the pre-display area  23  (Step S 8 : No), the detection control unit  133  transmits to the HMD  10  a request to cancel acquisition of sensor information corresponding to the orientation information (Step S 10 ). 
         [0082]    On receiving an acquisition request or a request to cancel acquisition of sensor information corresponding to the orientation information, the sensor control unit  17  of the HMD  10  determines whether or not there is an acquisition request (Step S 11 ). When there is an acquisition request (Step S 11 : Yes), the sensor control unit  17  outputs control information instructing the orientation detection sensor  13  to start output of the orientation information. Namely, the sensor control unit  17  starts acquisition of sensor information (Step S 12 ). When there is no acquisition request (Step S 11 : No), the sensor control unit  17  proceeds to Step S 13 . 
         [0083]    The sensor control unit  17  determines whether or not there is a request to cancel acquisition (Step S 13 ). When there is a request to cancel acquisition (Step S 13 : Yes), the sensor control unit  17  outputs control information instructing the orientation detection sensor  13  to end the output of the orientation information. Namely, the sensor control unit  17  ends acquisition of the sensor information (Step S 14 ). When there is no request to cancel acquisition (Step S 13 : No), the sensor control unit  17  proceeds to Step S 15 . 
         [0084]    The sensor control unit  17  determines whether the sensor information is being acquired (Step S 15 ). When the sensor information is being acquired (Step S 15 : Yes), the sensor control unit  17  sets the orientation information being acquired from the orientation detection sensor  13  as the sensor information, and transmits the sensor information to the display control device  100  (Step S 16 ). When the sensor information is not being acquired (Step S 15 : No), the sensor control unit  17  proceeds to Step S 20 . 
         [0085]    On receiving the sensor information including the orientation information (Step S 17 ), the calculation unit  132  of the display control device  100  sets the view  24  of the user, based on the display area  22 , the pre-display area  23 , and the orientation information. The calculation unit  132  outputs the set view  24  to the display control unit  131 . 
         [0086]    When the view  24  is input from the calculation unit  132 , the display control unit  131  displays the input view  24  superimposed on the display area  22  and the pre-display area  23 . In addition, the display control unit  131  displays object data which is within the display area  22  and within the view  24  on the display screen, with reference to the object data storage unit  121  (Step S 18 ). Namely, the display control unit  131  updates the display screen. 
         [0087]    The display control unit  18  of the HMD  10  updates the display of the display unit  14  according to the update of the display screen (Step S 19 ). The sensor control unit  17  determines whether or not the transmission and reception service has ended (Step S 20 ). In a case in which the transmission and reception service has not ended (Step S 20 : No), the sensor control unit  17  returns to Step S 11 . When the transmission and reception service is ended (Step S 20 : Yes), the sensor control unit  17  ends the processing. 
         [0088]    The display control unit  131  of the display control device  100  determines whether or not the application has ended (Step S 21 ). In a case in which the application has not ended (Step S 21 : No), the display control unit  131  returns to Step S 7 . In a case in which the application has ended (Step S 21 : Yes), the display control unit  131  ends the transmission and reception service (Step S 22 ), and ends the display control processing. This thereby enables the display control device  100  to reduce the power consumption of the HMD  10 . 
         [0089]    Note that, although in the above-described example the display control device  100  measures the location of the user, the embodiment is not limited thereto. For example, the HMD  10  may measure the location of the user. 
         [0090]    In this manner, the display control device  100  detects object data registered associated with a location in the area identified according to the location and the orientation of the HMD  10  detected by the sensors. In addition, the display control device  100  displays the detected object data on the HMD  10 . In addition, the display control device  100  calculates distances to the locations associated with each of the multiple object data. In addition, the display control device  100  performs control to suppress detection of the orientation of the HMD  10  based on a distribution of the calculated distances. This thereby enables the power consumption of the HMD  10  to be reduced. 
         [0091]    In addition, when none out of the multiple locations associated with the object data is included in the target area for displaying object data on the HMD  10 , the display control device  100  performs control to suppress detection of the orientation of the HMD  10 . This thereby enables the power consumption of the HMD  10  to be reduced when there is no object data to be displayed. 
         [0092]    In addition, when all of any of the multiple locations associated with the object data has a distance longer than a specified distance, the display control device  100  performs control to suppress detection of the orientation of the HMD  10 . This thereby enables the power consumption of the HMD  10  to be reduced when the object data are located farther away than the specified distance from the user. 
         [0093]    In addition, the display control device  100  receives sensor information from the HMD  10 . In addition, the display control device  100  measures the location. In addition, the display control device  100  transmits to the HMD  10 , a signal for controlling operation of the sensor included in the HMD  10  or transmission of sensor information, according to a determination result as to whether there is an object associated with a position having a given positional relationship with the measured location. As a result, the operation of the sensor of the HMD  10  or the transmission of the sensor information may be controlled according to whether or not there is an object. 
         [0094]    In addition, the sensor included in the HMD  10  is a sensor that detects the orientation of the HMD  10 . As a result, the detection of the orientation of the HMD  10  may be controlled according to whether or not there is an object. 
         [0095]    In addition, when the determination result indicates an absence of the object, the display control device  100  transmits to the HMD  10 , a signal for performing one or more out of a control for making the sensor&#39;s detection operation cycle longer and a control for making the cycle of transmission of sensor information longer, compared with the case in which the determination result indicates a presence of the object. This thereby enables the power consumption of the HMD  10  to be reduced. 
         [0096]    In addition, the display control device  100  receives the location detected in the location detection sensor  12 , from the HMD  10  that includes the location detection sensor  12  and the orientation detection sensor  13 . In addition, the display control device  100  transmits, to the HMD  10 , a signal for controlling the location detection sensor  12  and/or the orientation detection sensor  13  according to a determination result as to whether or not there is an object associated with a location having a given positional relationship with the location based on the location of receipt. The signal for controlling is a signal for controlling the operation of the location detection sensor  12  and/or the orientation detection sensor  13 , or transmission of the sensor information acquired by the location detection sensor  12  and/or the orientation detection sensor  13 . 
         [0097]    In addition, the display control device  100  receives the location detected by the location detection sensor  12 , from the HMD  10  that includes the location detection sensor  12  and the orientation detection sensor  13 . In addition, the display control device  100  transmits the signal to the HMD  10 . In addition, the display control device  100  performs control such that a signal is transmitted instructing the HMD  10  to transmit the orientation detected by the orientation detection sensor  13 , according to the search for an object associated with a location having a given positional relationship with a location based on the location of receipt. In addition, the display control device  100  performs control such that an image including a given object is transmitted to the HMD  10 , according to the search for an object based on the location and the orientation received from the HMD  10 . This thereby enables the object corresponding to the location and orientation of the HMD  10  to be displayed. 
         [0098]    Note that, although in the above-described example the detection of the orientation by the orientation detection sensor  13  is suppressed when there is no object data in the display area  22  nor in the pre-display area  23 , the embodiment is not limited thereto. For example, the detection of the orientation by the orientation detection sensor  13  may be suppressed when there is no object data in the display area  22 . 
         [0099]    In addition, in the above-described example, the equipment inspection in the factory is described above as an example, but the embodiment is not limited thereto. For example, the embodiment may be applied to a tourist guidance or the like at a sightseeing spot. 
         [0100]    In addition, in the above-described example, the example is described above in which the user wears the display control device  100  and the HMD  10 , but the embodiment is not limited thereto. For example, without using the HMD  10 , the screen may be displayed for example, on the display operation unit  112  of the display control device  100  which is a smartphone. 
         [0101]    In addition, the configuration element of each of the illustrated units does not have to be physically configured as illustrated in the diagrams. Namely, a specific form of distribution or integration of the units is not limited to those illustrated in the drawings, and all or some of the units may be configured so as to be distributed or integrated functionally or physically in any given unit according to various loads, usage conditions, and the like. For example, the calculation unit  132  and the detection control unit  133  may be integrated. In addition, the embodiment is not limited to the above-described order of the processing, and each of the processing steps may be executed simultaneously or changing the order to the extent no inconsistency arises in the processing. 
         [0102]    In addition, all or some of the various processing functions executed in each of the devices may be executed on a CPU (or a microcomputer such as a MPU or a micro controller unit (MCU)). In addition, all or some of the various processing functions may be obviously executed on a program analyzed and executed by the CPU (or the microcomputer such as the MPU or the MCU) or hardware by wired logic. 
         [0103]    Various kinds of processing described in the above embodiments may be implemented by a program prepared in advance being executed by a computer. Therefore, in the following description, an example of a computer that executes a program having functions similar to those of the above-described embodiment is described.  FIG. 12  is a diagram illustrating an example of a computer that executes a display control program. 
         [0104]    As illustrated in  FIG. 12 , a computer  300  includes a CPU  301  that executes various kinds of calculation processing, an input device  302  that accepts data input, and a monitor  303 . In addition, the computer  300  includes a medium reading device  304  that reads a program and the like from a storage medium, an interface device  305  for connecting with various devices, and a communication device  306  for connecting with another information processing device or the like by a wire or wirelessly. In addition, the computer  300  includes a RAM  307  that temporarily stores various information and a flash memory  308 . In addition, each of the devices  301  to  308  is coupled to a bus  309 . 
         [0105]    In the flash memory  308 , a display control program is stored that includes functions similar to those of the display control unit  131 , the calculation unit  132 , the detection control unit  133 , and the location measurement unit  134  illustrated in  FIG. 1 . In addition, in the flash memory  308 , various data for implementing the object data storage unit  121  and the display control program are stored. The input device  302  accepts, for example, inputs of various pieces of information such as operation information from the user of the computer  300 . The monitor  303  displays, for example, various screens such as a display screen for the user of the computer  300 . The interface device  305  is, for example, coupled to a headphone and the like. The communication device  306  includes, for example, functions similar to those of the first communication unit  110  and the second communication unit  111  illustrated in  FIG. 1 , and coupled to the HMD  10  and the network N, and transmits and receives various information to and from the HMD  10  and the server  200 . 
         [0106]    The CPU  301  executes various kinds of processing by reading each of the programs stored in the flash memory  308 , deploying the programs to the RAM  307 , and executing the programs. In addition, the programs allow the computer  300  to function as the display control unit  131 , the calculation unit  132 , the detection control unit  133 , and the location measurement unit  134  illustrated in  FIG. 1 . 
         [0107]    The above-described display control program does not have to be stored in the flash memory  308 . For example, a program stored in a storage medium readable by the computer  300  may be executed by the computer  300  reading the program. The storage medium readable by the computer  300  corresponds to, for example, a portable recording medium such as a compact disc-read-only memory (CD-ROM), a digital versatile disk (DVD), a universal serial bus (USB) memory, a semiconductor memory such as a flash memory, and a hard disk drive. In addition, a device coupled to a public lines, the Internet, a LAN, or the like may store such a display control program, and the computer  300  may read the display control program from the device and execute the display control program. 
         [0108]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.