Patent Publication Number: US-2017374359-A1

Title: Image providing system

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image providing system, and more particularly, to a video display technology using a head mounted display. 
     Description of Related Art 
     Conventionally, video display systems using head mounted displays have been developed. In addition, in such head mounted displays, technologies for detecting a visual line and performing input that is based on the visual line have been developed (for example, see Japanese Unexamined Patent Application Publication No. 2012-32568) 
     In head mounted displays, in addition to individual viewing of a video, the same video can be simultaneously viewed by a plurality of persons. 
     SUMMARY OF THE INVENTION 
     Meanwhile, compared to a case in which a video displayed on the same screen is simultaneously viewed by a plurality of persons, like in general movie viewing, in a case in which a video is viewed using mutually different head mounted displays by individuals, it is difficult to acquire an advantage of sharing a video with other persons. In addition, it is difficult to manage a plurality of users using the head mounted displays. 
     The present invention is in consideration of the problems described above, and an object thereof is to provide an image display system capable of displaying a video on a plurality of head mounted displays and managing a plurality of users. 
     According to one aspect of the present invention, there is provided an image providing system in which a plurality of head mounted display systems are connected to a server, the server including: a first communication control unit transmitting image data to the connected head mounted display systems; and a generation unit generating new image data according to information relating to visual lines of users transmitted from the head mounted display systems in accordance with the image data and outputting the generated new image data to the first communication control unit, and each of the head mounted display systems including: a display unit displaying the image data supplied from the server; a detection unit detecting a visual line of a user viewing the image data displayed on the display unit; and a second communication control unit transmitting information relating to the visual line detected by the detection unit to the server. 
     The generation unit may generate image data including information relating to visual lines detected by the plurality of head mounted display systems in the image data, and the first communication control unit may transmit the image data including the visual lines. 
     At least one of the plurality of head mounted display systems may be a host system and the other head mounted display systems may be client systems, the generation unit may generate image data including information relating to visual lines detected by a plurality of the client systems in the image data, and the first communication control unit may transmit the image data including the information relating to the visual lines to the host system. 
     The host system may further include an input unit receiving an input of a request requesting generation of image data to which information according to a visual line included in the image data is added from a user, the second communication control unit of the host system may transmit a request signal input to the input unit to the server, and the generation unit may generate new image data according to the request signal transmitted from the host system. 
     The generation unit may generate new image data by adding only information relating to a visual line detected by a selected head mounted display system among the plurality of head mounted display systems. 
     The server may further include a classification unit classifying a plurality of users as a group of users whose positions of the visual lines in the image data satisfy a predetermined condition, and a generation unit may generate image data for each user belonging to the group classified by the classification unit. 
     The server may further include an extraction unit extracting users whose gazing positions in visual lines are different from a target position, and the generation unit may generate image data guiding the users extracted by the extraction unit to the target position. 
     A request signal may include group information relating to the group of classified users, and the generation unit may generate image data including the group information. 
     The request signal may include guide information guiding a visual line, and the generation unit may generate image data including the guide information. 
     In addition, according to one aspect of the present invention, there is provided a server that is connected to a plurality of head mounted display systems and is used for an image providing system and includes a first communication control unit transmitting image data to the connected head mounted display systems and a generation unit generating new image data according to information relating to visual lines of users transmitted from the head mounted display systems in accordance with the image data and outputting the generated new image data to the first communication control unit 
     In addition, according to one aspect of the present invention, there is provided an image providing method used in an image providing system in which a server and a plurality of head mounted display systems are connected and includes: transmitting image data to the connected head mounted display systems by using the server; displaying the image data supplied from the server by using the head mounted display systems; detecting a visual line of a user viewing the image data displayed on a display unit by using each of the head mounted display system; transmitting information relating to the detected visual line to the server by using each of the head mounted display systems; and generating new image data according to the information relating to the visual line of the user transmitted from each of the head mounted display systems and transmitting the generated new image data to the head mounted display systems by using the server. 
     In addition, according to one aspect of the present invention, there is provided an image providing program, in an image providing system in which a server and a plurality of head mounted display systems are connected, that realizes: transmitting image data to the connected head mounted display systems; and generating new image data according to information relating to the visual line of the user transmitted from each of the head mounted display systems in accordance with the image data and transmitting the generated new image data to the head mounted display systems in the server. 
     According to the present invention, a video is displayed on a plurality of head mounted displays, and a plurality of users can be managed. 
    
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         FIG. 1  is a schematic diagram illustrating an image providing system according to a first embodiment. 
         FIG. 2A  is a block diagram illustrating the configuration of a server of the image providing system according to the first embodiment.  FIG. 2B  is a block diagram illustrating the configuration of a head mounted display system of the image providing system according to the first embodiment. 
         FIG. 3  is an external view illustrating the appearance of a user wearing a head mounted display according to the first embodiment. 
         FIG. 4  is a perspective view schematically illustrating an overview of an image display system of the head mounted display according to the first embodiment. 
         FIG. 5  is a diagram schematically illustrating the optical configuration of the image display system of the head mounted display according to the first embodiment. 
         FIG. 6  is a schematic diagram illustrating the calibration for detecting the direction of a visual line in the head mounted display system according to the first embodiment. 
         FIG. 7  is a schematic diagram illustrating the coordinates of the position of a user&#39;s cornea. 
         FIG. 8  is a flowchart illustrating the process performed by the server of the image providing system according to the first embodiment. 
         FIG. 9  is a flowchart illustrating the process performed by the head mounted display system of the image providing system according to the first embodiment. 
         FIGS. 10A to 10C  are examples of screen data displayed by the head mounted display system of the image providing system according to the first embodiment. 
         FIG. 11  is a flowchart illustrating another process performed by the server of the image providing system according to the first embodiment. 
         FIGS. 12A and 12B  are other examples of screen data displayed by the head mounted display system of the image providing system according to the first embodiment. 
         FIG. 13  is a flowchart illustrating another process performed by the server of the image providing system according to the first embodiment. 
         FIGS. 14A to 14C  are other examples of screen data displayed by the head mounted display system of the image providing system according to the first embodiment. 
         FIGS. 15A to 15C  are other examples of screen data displayed by the head mounted display system of the image providing system according to the first embodiment. 
         FIG. 16  is a schematic diagram illustrating an image providing system according to a second embodiment. 
         FIGS. 17A to 17C  are examples of screen data displayed by a host system of the image providing system according to the second embodiment. 
         FIG. 18  is a flowchart illustrating the process performed by the host system of the image providing system according to the second embodiment. 
         FIG. 19A  is a block diagram illustrating the circuit configuration of a server.  FIG. 19B  is a block diagram illustrating the circuit configuration of a head mounted display system. 
         FIG. 20  is a block diagram illustrating the configuration of a head mounted display system according to a third embodiment. 
         FIGS. 21A and 21B  are flowcharts illustrating the process performed by the head mounted display system according to the third embodiment. 
         FIGS. 22A and 22B  are examples of visualization displayed by the head mounted display system according to the third embodiment. 
         FIGS. 23A to 23C  illustrate another example of visualization displayed by the head mounted display system according to the third embodiment. 
         FIG. 24  illustrates a video display system according to a fourth embodiment and is a block diagram of the configuration of the video display system. 
         FIG. 25  illustrates the video display system according to the fourth embodiment and is a flowchart illustrating the operation of the video display system. 
         FIG. 26  illustrates the video display system according to the fourth embodiment and is an explanatory diagram of an example of video display before video processing displayed by the video display system. 
         FIG. 27  illustrates the video display system according to the fourth embodiment and is an explanatory diagram of an example of video display of a video processing state displayed by the video display system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An image providing system, a server, an image providing method, and an image providing program according to the present invention manage images provided for a plurality of head mounted displays. Hereinafter, embodiments of the present invention will be described with reference to the drawings. In description presented below, the same reference numeral is assigned to the same configuration, and duplicate description thereof will not be presented. 
     First Embodiment 
     As illustrated in  FIG. 1 , in an image providing system I according to a first embodiment, a server  400  and a plurality of head mounted display systems  1  ( 1 A to  1 C) are connected through a network  500 . 
     &lt;&lt;Server&gt;&gt; 
     The server  400 , as illustrated in  FIG. 2A , is an information processing apparatus including a central processing unit (CPU)  40 , a storage device  41 , a communication interface (communication I/F)  42 , and the like. The storage device  41  of the server  400  stores image data dl and an image providing program P 1 . This server  400  provides the image data dl for a head mounted display  100 . At this time, by executing the image providing program P 1 , the CPU  40  performs a process as a first communication control unit  401 , a generation unit  402 , a classification unit  403 , and an extraction unit  404 . 
     The image data dl is not limited to still image data but may be moving image data. In description presented below, the image data dl is moving image data, and more particularly, is assumed to be video data including audio data. 
     The first communication control unit  401  transmits image data to the connected head mounted display system  1  through the communication I/F  42 . For example, the first communication control unit  401  transmits image data  411  stored in the storage device  41 . Alternatively, the first communication control unit  401  transmits image data generated by the generation unit  402 . 
     The generation unit  402  generates new image data in accordance with a user&#39;s visual line transmitted from the head mounted display system  1  in accordance with image data transmitted by the first communication control unit  401  and outputs the generated new image data to the first communication control unit  401 . 
     For example, the generation unit  402  adds an image that is based on visual line data received from a plurality of the head mounted display systems  1  to the image data  411  stored in the storage device  41 , thereby generating new image data. When the visual line data is added, the generation unit  402  may generate new image data by adding all the visual line data received from the head mounted display systems  1 . Alternatively, the generation unit  402  may generate new image data by adding only visual line data received from some of the head mounted display systems  1  that are selected. 
     In addition, the generation unit  402  may generate new image data by adding an image that is based on data of groups classified by the classification unit  403  to be described later to the image data  411  stored in the storage device  41 . When the data of the groups is added, new image data may be generated for each group. In other words, the generation unit  402  generates image data different for each group, and each head mounted display system  1  is provided with image data generated for a group to which it belongs. 
     Furthermore, the generation unit  402  may generate new image data by adding an image that is based on guide data to the image data  411  stored in the storage device  41  for users classified by the extraction unit  404  to be described later. The image that is based on the guide data guides a user to a target position, in other words, a position to be viewed in the image. More specifically, the image that is based on the guide data is represented by an icon (for example, an arrow or a pop-up having “attention” written therein), a frame, or the like. 
     The classification unit  403  classifies users whose visual line data satisfies a predetermined condition into groups. As a classification method used by the classification unit  403 , for example, the following methods may be considered. 
     1. Classification Using Visual Line Data 
     (1) Group of Users Gazing at Same Object 
     The classification unit  403  may classify users whose visual lines are on the same object into the same group. At this time, the classification unit  403  may extract not only users whose visual lines are on a target object but also users whose visual lines are within a predetermined distance from a certain point (for example, a center point of the target object). In addition, the classification unit  403  may extract users whose visual lines are within a predetermined distance from a target object. 
     (2) Group of Users Whose Visual Lines are within Predetermined Range 
     The classification unit  403  may classify users whose visual lines are within a predetermined range into the same group. For example, the classification unit  403  may classify groups of users such as a group in which users whose visual lines are at the center of the image, a group in which users whose visual lines are on the right side of the image, and the like. In addition, at this time, the classification unit  403  may classify users whose visual lines are within a predetermined distance into the same group. 
     (3) Group Classified by Clustering Process 
     The classification unit  403  may perform clustering of gazing coordinate positions specified from visual line information and classify users of each group. 
     (4) Group of Users Whose Visual Lines are in Same Area 
     The classification unit  403  may divide an image into a plurality of areas in advance and classify users whose visual lines are in the same area into the same group. 
     (5) Other 
     In addition, as described above, when user groups are classified according to visual lines, not only users whose visual lines have the relations described above at the same time but also users whose visual lines have the relations described above within a predetermined period may be classified into the same group. More specifically, in the example of (1) described above, even when the time at which a target object is viewed does not completely match, users viewing a target object for a predetermined time or more in a specific time period may be classified into the same group. For example, users gazing at a target object for at least 15 seconds or more during three minutes in which a specific image is displayed are classified into the same group. 
     2. Classification Using Visual Line Data and User&#39;s Behavior 
     In addition, the classification unit  403  may classify groups by using user&#39;s behaviors as illustrated below in addition to visual line data. 
     (1) User&#39;s Operation 
     The classification unit  403  may classify users whose visual lines satisfy a predetermined condition as described above and who have performed a specific behavior at the time point into the same group. For example, users whose visual lines satisfy a predetermined condition and who have moved their heads to the right may be classified into the same group. In addition, users whose visual lines satisfy a predetermined condition and who shake their heads may be classified into the same group. In this way, users having similar feelings or ways of thinking may be classified into the same group. A user&#39;s behavior, for example, is detected by a sensor such as a gyro sensor of the head mounted display  100  and is transmitted from the head mounted display system  1  to the server  400 . 
     (2) Signal Input Performed by User 
     The classification unit  403  may classify users whose visual lines satisfy a predetermined condition as described above and who have input a predetermined operation signal at that time point into the same group. For example, when an image provided for the head mounted display system  1  is an image of a video lesson, users who have input the same answer for a question by using an operation signal may be classified into the same group. In this way, users having the same thought can be classified into a group performing group work or the like. In addition, when an image provided for the head mounted display system  1  is an image of a video game, users who have moved a character in the same direction by using an operation signal may be classified into the same group. In this way, users having the same thought can be classified into a group. The operation signal used here is input by using an input device  23  of the head mounted display system  1  and is transmitted to the server  400 . 
     (3) User&#39;s Behavior History 
     The classification unit  403  may classify users whose visual lines satisfy a predetermined condition as described above and who have performed a predetermined behavior in the past into the same group. As a behavior performed in the past, for example, participation in an event, inputting an operation signal, or the like may be considered. For example, when an image provided for the head mounted display system  1  is an image of a video lesson, users who took a specific course in the past or users who have not taken a specific course may be classified into the same group. In this way, users having a specific knowledge or users having no specific knowledge can be classified as a group performing a group work or the like. In addition, for example, in a case where an image provided for the head mounted display system  1  is an image of a video game, users who have performed the same behavior in the past may be classified into the same group. In this way, users having the same thought can be classified into a group. Here, for example, a user&#39;s behavior history is stored in the storage device of the server  400  as behavior history data. This behavior history data may be configured by an on/off flag specifying a behavior performed by a user in the past, a behavior not performed by a user in the past, or the like. 
     The extraction unit  404  extracts users having gazing positions different from a target position using visual lines. For example, the extraction unit  404  extracts users whose positions of the visual lines are separate from the coordinates of a target position set in advance by a predetermined distance. In addition, the extraction unit  404  may extract users by using user&#39;s behaviors in addition to visual line data. As the user&#39;s behaviors, as described above, user&#39;s operations, signal inputs performed by users, user&#39;s behavior histories, or the like. 
     &lt;&lt;Head Mounted Display System&gt;&gt; 
     Each head mounted display system  1  ( 1 A to  1 C) includes a head mounted display  100  ( 100 A to  100 C) and a visual line detecting device  200  ( 200 A to  200 C). 
     As illustrated in  FIG. 2B , the visual line detecting device  200  includes: a CPU  20 ; a storage device  21 ; a communication I/F  22 ; an input device  23 ; and an output device  24 . In the storage device  21 , a visual line detecting program P 2  is stored. By executing this visual line detecting program P 2 , the CPU  20  performs a process as a second communication control unit  201 , a detection unit  202 , an image generating unit  203 , and an image output unit  204 . Here, while the communication I/F  22  is described to be used for communication with the server  400  through the network  500  and used for communication with the head mounted display  100 , a different interface may be used for each type of communication. 
     The second communication control unit  201  receives image data transmitted from the server  400  through the communication I/F  22 . In addition, the second communication control unit  201  transmits visual line data detected by the detection unit  202  to the server  400  through the communication I/F  22 . 
     The detection unit  202  detects visual lines of users viewing image data displayed on the display unit  121 . 
     The image generating unit  203 , for example, using a method to be described later with reference to  FIG. 6 , generates an image to be displayed on the head mounted display  100 . 
     The image output unit  204  outputs image data received from the server to the head mounted display through the communication I/F  22 . 
     The head mounted display  100  includes a communication I/F  110 , a third communication control unit  118 , a display unit  121 , an infrared ray emitting unit  122 , an image processing unit  123 , an imaging unit  124 , and the like. 
       FIG. 4  is a block diagram illustrating the configuration of the head mounted display system  1  according to an embodiment. As illustrated in  FIG. 4 , the head mounted display  100  of the head mounted display system  1  includes a communication interface (I/F)  110 , a third communication control unit  118 , a display unit  121 , an infrared ray emitting unit  122 , an image processing unit  123 , and an imaging unit  124 . 
     The display unit  121  has a function of displaying image data delivered from the third communication control unit  118  on an image display device  108 . The display unit  121  displays a test image as image data. In addition, the display unit  121  displays a marker image output from the image generating unit  203  at designated coordinates of the image display device  108 . 
     The infrared ray emitting unit  122  emits infrared rays to the right eye or the left eye of the user by controlling an infrared light source  103 . 
     The image processing unit  123  performs image processing as necessary for an image captured by the imaging unit  124  and delivers the processed image to the third communication control unit  118 . 
     The imaging unit  124  captures an image including near infrared light reflected by each eye by using a camera  116 . In addition, the imaging unit  124  captures an image including a user&#39;s eye gazing at the marker image displayed on the image display device  108 . The imaging unit  124  delivers the images acquired through the capturing process to the third communication control unit  118  or the image processing unit  123 . 
       FIG. 3  is a diagram schematically illustrating an overview of the head mounted display system  1  according to an embodiment. As illustrated in  FIG. 3 , the head mounted display  100  is mounted on the head of the user  300  to be used. 
     The visual line detecting device  200  detects the visual line direction of at least one of the right eye and the left eye of the user who wears the head mounted display  100  and specifies a focal point of the user, in other words, a portion at which the user gazes in a three-dimensional image displayed on the head mounted display. In addition, the visual line detecting device  200  functions also as a video generating device generating a video displayed by the head mounted display  100 . While not particularly limited, as an example, the visual line detecting device  200  is a device capable of reproducing a video such as a stationary gaming device, a portable gaming device, a PC, a tablet, a smartphone, a phablet, a video player, or a television receiver. The visual line detecting device  200  is connected to the head mounted display  100  in a wireless or wired manner. 
     In the example illustrated in  FIG. 3 , the visual line detecting device  200  is wirelessly connected to the head mounted display  100 . The wireless connection of the visual line detecting device  200  with the head mounted display  100 , for example, may be realized by an existing radio communication technology such as Wi-Fi (registered trademark) or Bluetooth (registered trademark). While not particularly limited, as an example, the transmission of a video between the head mounted display  100  and the visual line detecting device  200  is performed in compliance with a standard such as Miracast (trademark), WiGig (trademark), or WHDI (trademark). In addition, any other communication technology may be used, and, for example, a sound wave communication technology or an optical transmission technology may be used. 
       FIG. 3  illustrates an example in which the head mounted display  100  and the visual line detecting device  200  are separate devices. However, the visual line detecting device  200  may be built in the head mounted display  100 . 
     The head mounted display  100  includes a casing  150 , a mounting fixture  160 , and headphones  170 . The casing  150  houses an image display system used for presenting a video to the user  300  such as an image display device and a radio transmission module not illustrated in the drawing such as a Wi-Fi module or a Bluetooth (registered trademark) module. The mounting fixture  160  is used to mount the head mounted display  100  on the head of the user  300 . The mounting fixture  160 , for example, may be realized by a belt, a stretchable band, or the like. When the user  300  wears the head mounted display  100  by using the mounting fixture  160 , the casing  150  is arranged at a position covering the eyes of the user  300 . For this reason, when the user  300  wears the head mounted display  100 , the visual field of the user  300  is blocked by the casing  150 . 
     The headphones  170  output audio of a video reproduced by the visual line detecting device  200 . The headphones  170  may not be fixed to the head mounted display  100 . Also in a state in which the head mounted display  100  is mounted using the mounting fixture  160 , the user  300  can freely attach or detach the headphones  170 . The headphones  170  are not an essential configuration. 
       FIG. 4  is a perspective view schematically illustrating an overview of the image display system  130  of the head mounted display  100  according to an embodiment. More specifically,  FIG. 4  is a diagram illustrating an area of the casing  150  according to the embodiment that faces the corneas  302  of the user  300  when the head mounted display  100  is mounted. 
     As illustrated in  FIG. 4 , a left-eye convex lens  114   a  is arranged at a position facing the cornea  302   a  of the left eye of the user  300  when the user  300  wears the head mounted display  100 . Similarly, a right-eye convex lens  114   b  is arranged at a position facing the cornea  302   b  of the right eye of the user  300  when the user  300  wears the head mounted display  100 . The left-eye convex lens  114   a  and the right-eye convex lens  114   b  are respectively gripped by a left-eye lens holding part  152   a  and a right-eye lens holding part  152   b.    
     Hereinafter, in the present specification, each of the left-eye convex lens  114   a  and the right-eye convex lens  114   b  will be simply referred to as a “convex lens  114 ” unless the convex lenses need to be particularly discriminated from each other. Similarly, each of the cornea  302   a  of the left eye of the user  300  and the cornea  302   b  of the right eye of the user  300  will be simply referred to as a “cornea  302 ” unless the corneas need to be particularly discriminated from each other. Each of the left-eye lens holding part  152   a  and the right-eye lens holding part  152   b  will be referred to as a “lens holding part  152 ” unless the lens holding parts need to be particularly discriminated from each other. 
     In the lens holding part  152 , a plurality of infrared light sources  103  are included. In order to avoid complication, in  FIG. 4 , infrared light sources emitting infrared light to the cornea  302   a  of the left eye of the user  300  are illustrated together as infrared light sources  103   a , and infrared light sources emitting infrared light to the cornea  302   b  of the right eye of the user  300  are illustrated together as infrared light sources  103   b . Hereinafter, each of the infrared light sources  103   a  and the infrared light sources  103   b  will be referred to as an “infrared light source  103 ” unless the infrared light sources  103   a  and  103   b  need to be particularly discriminated from each other. In the example illustrated in  FIG. 4 , six infrared light sources  103   a  are included in the left-eye lens holding part  152   a . Similarly, six infrared light sources  103   b  are included in the right-eye lens holding part  152   b . In this way, by arranging the infrared light sources  103  in the lens holding parts  152  gripping the convex lenses  114  without directly arranging the infrared light sources  103  in the convex lenses  114 , the infrared light sources  103  can be easily attached. Generally, since the lens holding parts  152  are configured using a resin or the like, processing used for attaching the infrared light sources  103  can be performed more easily for the lens holding parts  152  than for the convex lenses  114  configured using glass or the like. 
     As described above, the lens holding parts  152  are members gripping the convex lenses  114 . Accordingly, the infrared light sources  103  included in the lens holding parts  152  are arranged on the peripheries of the convex lenses  114 . Here, while the number of the infrared light sources  103  emitting infrared light to each eye is six, the number is not limited thereto. Thus, in correspondence with each eye, at least one infrared light source may be arranged, and two or more infrared light sources are preferably arranged. 
       FIG. 5  is a diagram schematically illustrating the optical configuration of the image display system  130  housed by the casing  150  according to an embodiment and is a diagram of a case in which the casing  150  illustrated in  FIG. 5  is viewed from a side face of the left-eye side. The image display system  130  includes infrared light sources  103 , an image display device  108 , an optical device  112 , a convex lens  114 , a camera  116 , and a third communication control unit  118 . 
     The infrared light source  103  is a light source capable of emitting light of a near-infrared wavelength band (about 700 nm to 2500 nm). Generally, the infrared light is light of a wavelength band of non-visible light that cannot be observed by the naked eye of the user  300 . 
     The image display device  108  displays an image to be presented to the user  300 . The image displayed by the image display device  108  is generated by the generation unit  402  disposed inside the server  400  or the image generating unit  203  disposed inside the visual line detecting device  200 . In addition, the image may be generated by the generation unit  402  and the image generating unit  203 . The image display device  108 , for example, may be realized by an existing liquid crystal display (LCD), organic electroluminescence display (organic EL display), or the like. 
     When the user  300  wears the head mounted display  100 , the optical device  112  is arranged between the image display device  108  and the cornea  302  of the user  300 . The optical device  112  has characteristics of transmitting visible light generated by the image display device  108  but reflecting near-infrared light. This optical device  112  has a characteristic of reflecting light of a specific frequency band and, for example, is a transparent flat plate, a hot mirror, a prism, or the like. 
     The convex lens  114  is arranged on the opposite side of the image display device  108  with respect to the optical device  112 . In other words, when the user  300  wears the head mounted display  100 , the convex lens  114  is arranged between the optical device  112  and the cornea  302  of the user  300 . In other words, when the head mounted display  100  is worn by the user  300 , the convex lens  114  is arranged at a position facing the cornea  302  of the user  300 . 
     The convex lens  114  collects image display light transmitted through the optical device  112 . For this reason, the convex lens  114  functions as an image enlarging unit that enlarges an image generated by the image display device  108  and presents the enlarged image to the user  300 . While only one of each convex lens  114  is illustrated in  FIG. 5  for the convenience of description, the convex lenses  114  may be lens groups configured by combining various lenses or a one-side convex lens of which one side has curvature and the other side has a flat face. 
     A plurality of infrared light sources  103  are arranged on the periphery of the convex lens  114 . Each of the infrared light sources  103  emits infrared light toward the cornea  302  of the user  300 . 
     While not illustrated in the drawing, the image display system  130  of the head mounted display  100  according to an embodiment includes two image display devices  108  and can independently generate an image to be presented to the right eye of the user  300  and an image to be presented to the left eye. For this reason, the head mounted display  100  according to an embodiment can present a right-eye parallax image and a left-eye parallax image respectively to the right eye and the left eye of the user  300 . In this way, the head mounted display  100  according to an embodiment can present a stereoscopic video having a depth feeling to the user  300 . 
     As described above, the optical device  112  transmits visible light and reflects or partially reflects near-infrared light or reflects light of a specific frequency. Accordingly, the image light emitted by the image display device  108  is transmitted through the optical device  112  and arrives at the cornea  302  of the user  300 . In addition, infrared light that is emitted from the infrared light source  103  and is reflected by a reflection area disposed inside the convex lens  114  arrives at the cornea  302  of the user  300 . 
     The infrared light arriving at the cornea  302  of the user  300  is reflected by the cornea  302  of the user  300  and travels toward the side of the convex lens  114 . This infrared light is transmitted through the convex lens  114  and is reflected by the optical device  112 . The camera  116  includes a filter blocking visible light and captures the near-infrared light reflected by the optical device  112 . In other words, the camera  116  is a near-infrared camera that captures near-infrared light that is emitted from the infrared light source  103  and is reflected by the cornea of the eye of the user  300 . 
     While not illustrated in the drawing, the image display system  130  of the head mounted display  100  according to an embodiment includes two cameras  116 , in other words, a first imaging unit that captures an image including infrared light reflected by the right eye and a second imaging unit that captures an image including infrared light reflected by the left eye. In this way, images used for detecting the directions of the visual lines of both the right eye and the left eye of the user  300  can be acquired. 
     The third communication control unit  118  outputs the images captured by the cameras  116  to the visual line detecting device  200  detecting the direction of the visual line of the user  300 . More specifically, the third communication control unit  118  transmits the images captured by the cameras  116  to the visual line detecting device  200  through the communication I/F  110 . While the details of the detection unit  202  functioning as a visual line direction detecting unit will be described later, the detection unit  202  is realized by a video displaying program executed by a central processing unit (CPU) of the visual line detecting device  200 . In addition, when the head mounted display  100  includes calculation resources such as a CPU, a memory, and the like, the CPU of the head mounted display  100  may execute a program realizing the visual line direction detecting unit. 
     While details will be described later, in an image captured by the camera  116 , bright spots due to the near-infrared light reflected by the cornea  302  of the user  300  and an image of the eye including the cornea  302  of the user  300  observed in a near-infrared wavelength band are captured. 
     While the configuration for presenting an image to the left eye of the user  300  in the image display system  130  according to an embodiment has been mainly described, a configuration for presenting an image to the right eye of the user  300  is similar to that described above. 
     Next, detection of the direction of a visual line according to an embodiment will be described. 
       FIG. 6  is a schematic diagram illustrating the calibration for detecting the direction of a visual line according to an embodiment. The direction of the visual line of the user  300  is acquired by analyzing a video that is captured by the camera  116  and is output by the third communication control unit  118  to the visual line detecting device  200  using the detection unit  202  disposed inside the visual line detecting device  200 . 
     The image generating unit  203  generates nine points (marker images) Q 1  to Q 9  as illustrated in  FIG. 6  and displays the generated points on the image display device  108  of the head mounted display  100 . The visual line detecting device  200  causes the user  300  to sequentially gaze at the points Q 1  to Q 9 . At this time, the user  300  is required to gaze at each of the points by moving only his or her eyeballs as much as possible without moving his or her neck, and the camera  116  captures images including the cornea  302  of the user  300  when the user  300  gazes at the nine points Q 1  to Q 9 . 
       FIG. 7  is a schematic diagram illustrating the coordinates of the position of the cornea  302  of the user  300 . The detection unit  202  disposed inside the visual line detecting device  200  detects bright spots  105  originating from infrared light by analyzing an image captured by the camera  116 . When the user  300  gazes at each of the points by only moving his or her eyeballs, it is assumed that the positions of the bright spots  105  do not move regardless of at which point the user gazes. Thus, the detection unit  202  sets a two-dimensional coordinate system  306  inside the image captured by the camera  116  based on the detected bright spots  105 . 
     In addition, the detection unit  202 , by analyzing the image captured by the camera  116 , detects the center P of the cornea  302  of the user  300 . This, for example, can be realized using existing image processing such as a Hough transform or an edge extraction process. In this way, the detection unit  202  can acquire the coordinates of the center P of the cornea  302  of the user  300  in the set two-dimensional coordinate system  306 . 
     In the case illustrated in  FIG. 6 , in the two-dimensional coordinate system set on the display screen displayed by the image display device  108 , the coordinates of the points Q 1  to Q 9  will be respectively denoted by Q 1 (x1, y1) T , Q 2 (x2, y2) T , . . . , and Q 9 (x9, x9) T . The coordinates of each point, for example, are configured by the number of a pixel positioned at the center of the point. In addition, the centers P of the cornea  302  of the user  300  when the user  300  gazes at the points Q 1  to Q 9  are respectively denoted by points P 1  to P 9 . At this time, the coordinates of the points P 1  to P 9  in the two-dimensional coordinate system  306  will be denoted by P 1 (X1, Y1) T , P 2 (X2, Y2) T , . . . , and P 9 (Z9, Y9) T . Here, “T” represents the transposition of a vector or a matrix. 
     Now, a matrix M having a size of 2×2 is defined as in the following Equation (1) 
     
       
         
           
             
               
                 
                   M 
                   = 
                   
                     ( 
                     
                       
                         
                           
                             m 
                             11 
                           
                         
                         
                           
                             m 
                             12 
                           
                         
                       
                       
                         
                           
                             m 
                             21 
                           
                         
                         
                           
                             m 
                             22 
                           
                         
                       
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     At this time, when the matrix M satisfies the following Equation (2), the matrix M is a matrix projecting in the direction of the visual line of the user  300  onto an image surface displayed by the image display device  108 . 
         P   N   =MQ   N ( N= 1, . . . ,9)  (2)
 
     When Equation (2) described above is written specifically, the following Equation (3) is obtained. 
     
       
         
           
             
               
                 
                   
                     ( 
                     
                       
                         
                           
                             x 
                             1 
                           
                         
                         
                           
                             x 
                             2 
                           
                         
                         
                           … 
                         
                         
                           
                             x 
                             9 
                           
                         
                       
                       
                         
                           
                             y 
                             1 
                           
                         
                         
                           
                             y 
                             2 
                           
                         
                         
                           … 
                         
                         
                           
                             y 
                             9 
                           
                         
                       
                     
                     ) 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             
                               m 
                               11 
                             
                           
                           
                             
                               m 
                               12 
                             
                           
                         
                         
                           
                             
                               m 
                               21 
                             
                           
                           
                             
                               m 
                               22 
                             
                           
                         
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         
                           
                             
                               X 
                               1 
                             
                           
                           
                             
                               X 
                               2 
                             
                           
                           
                             … 
                           
                           
                             
                               X 
                               9 
                             
                           
                         
                         
                           
                             
                               Y 
                               1 
                             
                           
                           
                             
                               Y 
                               2 
                             
                           
                           
                             … 
                           
                           
                             
                               Y 
                               9 
                             
                           
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     When Equation (3) is transformed, the following Equation (4) is obtained. 
     
       
         
           
             
               
                 
                   
                     
                       ( 
                       
                         
                           
                             
                               x 
                               1 
                             
                           
                         
                         
                           
                             
                               x 
                               2 
                             
                           
                         
                         
                           
                             ⋮ 
                           
                         
                         
                           
                             
                               x 
                               9 
                             
                           
                         
                         
                           
                             
                               y 
                               1 
                             
                           
                         
                         
                           
                             
                               y 
                               2 
                             
                           
                         
                         
                           
                             ⋮ 
                           
                         
                         
                           
                             
                               y 
                               9 
                             
                           
                         
                       
                       ) 
                     
                     = 
                     
                       
                         ( 
                         
                           
                             
                               
                                 X 
                                 1 
                               
                             
                             
                               
                                 Y 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 X 
                                 2 
                               
                             
                             
                               
                                 Y 
                                 2 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                           
                           
                             
                               
                                 X 
                                 9 
                               
                             
                             
                               
                                 Y 
                                 9 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               
                                 X 
                                 1 
                               
                             
                             
                               
                                 Y 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               
                                 X 
                                 2 
                               
                             
                             
                               
                                 Y 
                                 2 
                               
                             
                           
                           
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                             
                               ⋮ 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               
                                 X 
                                 9 
                               
                             
                             
                               
                                 Y 
                                 9 
                               
                             
                           
                         
                         ) 
                       
                        
                       
                         ( 
                         
                           
                             
                               
                                 m 
                                 11 
                               
                             
                           
                           
                             
                               
                                 m 
                                 12 
                               
                             
                           
                           
                             
                               
                                 m 
                                 21 
                               
                             
                           
                           
                             
                               
                                 m 
                                 22 
                               
                             
                           
                         
                         ) 
                       
                     
                   
                    
                   
                     
 
                   
                    
                   
                     
                       y 
                       = 
                       
                         
                           
                             ( 
                             
                               
                                 
                                   
                                     x 
                                     1 
                                   
                                 
                               
                               
                                 
                                   
                                     x 
                                     2 
                                   
                                 
                               
                               
                                 
                                   ⋮ 
                                 
                               
                               
                                 
                                   
                                     x 
                                     9 
                                   
                                 
                               
                               
                                 
                                   
                                     y 
                                     1 
                                   
                                 
                               
                               
                                 
                                   
                                     y 
                                     2 
                                   
                                 
                               
                               
                                 
                                   ⋮ 
                                 
                               
                               
                                 
                                   
                                     y 
                                     9 
                                   
                                 
                               
                             
                             ) 
                           
                            
                           A 
                         
                         = 
                         
                           ( 
                           
                             
                               
                                 
                                   X 
                                   1 
                                 
                               
                               
                                 
                                   Y 
                                   1 
                                 
                               
                               
                                 0 
                               
                               
                                 0 
                               
                             
                             
                               
                                 
                                   X 
                                   2 
                                 
                               
                               
                                 
                                   Y 
                                   2 
                                 
                               
                               
                                 0 
                               
                               
                                 0 
                               
                             
                             
                               
                                 ⋮ 
                               
                               
                                 ⋮ 
                               
                               
                                 ⋮ 
                               
                               
                                 ⋮ 
                               
                             
                             
                               
                                 
                                   X 
                                   9 
                                 
                               
                               
                                 
                                   Y 
                                   9 
                                 
                               
                               
                                 0 
                               
                               
                                 0 
                               
                             
                             
                               
                                 0 
                               
                               
                                 0 
                               
                               
                                 
                                   X 
                                   1 
                                 
                               
                               
                                 
                                   Y 
                                   1 
                                 
                               
                             
                             
                               
                                 0 
                               
                               
                                 0 
                               
                               
                                 
                                   X 
                                   2 
                                 
                               
                               
                                 
                                   Y 
                                   2 
                                 
                               
                             
                             
                               
                                 ⋮ 
                               
                               
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                                 ⋮ 
                               
                               
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                                 0 
                               
                               
                                 0 
                               
                               
                                 
                                   X 
                                   9 
                                 
                               
                               
                                 
                                   Y 
                                   9 
                                 
                               
                             
                           
                           ) 
                         
                       
                     
                     , 
                     
                       x 
                       = 
                       
                         ( 
                         
                           
                             
                               
                                 m 
                                 11 
                               
                             
                           
                           
                             
                               
                                 m 
                                 12 
                               
                             
                           
                           
                             
                               
                                 m 
                                 21 
                               
                             
                           
                           
                             
                               
                                 m 
                                 22 
                               
                             
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     Thus, the following Equation (5) is acquired. 
         y=Ax   (5)
 
     In Equation (5), the elements of the vector y are the coordinates of the points Q 1  to Q 9  displayed on the image display device  108  by the detection unit  202  and thus are known. In addition, the elements of the matrix A are the coordinates of the vertex P of the cornea  302  of the user  300  and thus can be acquired. Accordingly, the detection unit  202  can acquire the vector y and the matrix A. In addition, the vector x that is a vector acquired by aligning the elements of the transformation matrix M is unknown. Thus, a problem of estimating the matrix M is a problem of acquiring the unknown vector x when the vector y and the matrix A are known. 
     In Equation (5), when the number of equations (in other words, the number of points Q presented to the user  300  when the detection unit  202  performs calibration) is larger than the number of unknown quantities (in other words, the number of elements of the vector x which is “4”), an overdetermined problem is formed. In the example represented in Equation (5), since the number of equations is nine, an overdetermined problem is formed. 
     An error vector between the vector y and the vector Ax is set as a vector e. In other words, e=y−Ax. At this time, for the purpose of minimizing a square sum of the elements of the vector e, an optimal vector x opt  is acquired using the following Equation (6). 
         x   opt =( A   T   A ) −1   A   T   y   (6)
 
     Here, “−1” represents an inverse matrix. 
     The detection unit  202  composes the matrix M represented in Equation (1) by using the elements of the acquired vector x opt . In this way, by using the coordinates of the vertex P of the cornea  302  of the user  300  and the matrix M, the detection unit  202  can estimate a place on a moving image displayed on the image display device  108  at which the right eye of the user  300  gazes based on Equation (2). Here, the detection unit  202  further receives information of a distance between the user&#39;s eye and the image display device  108  from the head mounted display  100  and corrects the values of coordinates at which the user gazes in accordance with the information of the distance. In addition, a deviation in the estimation of a gazing position according to the distance between the user&#39;s eye and the image display device  108  may be ignored as the range of an error. In this way, the detection unit  202  can calculate a right-eye visual line vector joining a gazing point of the right eye on the image display device  108  and the vertex of the cornea of the user&#39;s right eye. Similarly, the detection unit  202  can calculate a left-eye visual line vector joining a gazing point of the left eye on the image display device  108  and the vertex of the cornea of the user&#39;s left eye. In addition, a user&#39;s gazing point on a two-dimensional plane can be specified using the visual line vector of only one eye, and by acquiring the visual line vectors of both eyes, information of the user&#39;s gazing point in the depth direction can be calculated as well. In this way, the visual line detecting device  200  can specify a user&#39;s gazing point. The method of specifying a gazing point illustrated here is an example, and thus a user&#39;s gazing point may be specified using other techniques described in this embodiment. 
     &lt;&lt;Example in which Visual Line Information of User is Displayed on Image&gt;&gt; 
     An example of a process performed when visual line information of a user is displayed on an image will be described with reference to  FIGS. 8 and 9 .  FIG. 8  is a flowchart illustrating the process performed by the server  400 . 
     First, the server  400  transmits image data dl stored in the storage device  41  to each head mounted display system  1  connected through the network  500  (S 01 ). 
     Thereafter, the server  400  receives visual line data of users viewing the image data dl from each head mounted display system  1  (S 02 ). 
     In addition, the server  400  generates new image data including the received visual line data of each head mounted display system  1  (S 03 ). 
     Subsequently, the server  400  transmits the new image data to each head mounted display system  1  (S 04 ). 
     Until an end request is received, the server  400  continues the process of Steps S 02  to S 04  (S 05 ). 
       FIG. 9  is a flowchart illustrating the process performed by the head mounted display system  1 . When image data is received from the server  400  (S 11 ), the head mounted display system  1  displays the received image data (S 12 ). 
     In addition, the head mounted display system  1  detects visual line data of users viewing the displayed image data (S 13 ). 
     Thereafter, the head mounted display system  1  transmits the detected visual line data to the server  400  (S 14 ). 
     Until an end request is received, the head mounted display system  1  repeats the process of Steps S 11  to S 14  (S 15 ). 
       FIG. 10( a )  is an example of an image that is transmitted by the server  400  in Step S 01  and is displayed in the head mounted display system  1  in Step S 12 . 
       FIG. 10( b )  is an example of an image including visual line data. This is image data including the visual line data generated in Step S 03  in accordance with the detection of the visual line data in the head mounted display system  1  in Step S 13 . Here, in the example, the visual line data of users is added to the image data using identifiers A to K. 
       FIG. 10( c )  is another example of an image including visual line data.  FIG. 10( b )  is an example in which visual lines of all the users viewing the same image data, in other words, 11 persons of the identifiers A to K, are included. In contrast to this,  FIG. 10( c )  is an example of image data including visual lines of only some users. 
     When image data including visual line data is generated, the generation unit  402  of the server  400 , as illustrated in  FIG. 10( b ) , may generate image data including the visual lines of all the users. In addition, as illustrated in  FIG. 10( c ) , the generation unit  402  may generate image data including the visual lines of some users. 
     &lt;&lt;Example in which Users are Grouped Based on Visual Line Information&gt;&gt; 
     An example of the process performed when users are grouped using visual line information of the users will be described with reference to  FIG. 11 .  FIG. 11  is a flowchart illustrating the process performed by the server  400 . 
     First, the server  400  transmits image data dl stored in the storage device  41  to each head mounted display system  1  connected through the network  500  (S 21 ). 
     Thereafter, the server  400  receives visual line data of users viewing the image data dl from each head mounted display system  1  (S 22 ). 
     Next, the server  400  extracts users whose visual lines satisfy a predetermined condition (S 23 ). For example, the server  400 , as described above, extracts a group in which the visual lines of users are on the same object, a group in which visual lines of users are in a predetermined range, a group specified by a clustering process, a group in which visual lines of users are in the same area, and the like. At this time, in addition to the visual lines of users, the server  400  may use the behaviors of the users as an extraction condition. 
     The server  400  generates a group for every extracted user (S 24 ). In accordance with the extraction condition and the visual line data of users, the number of groups and the number of users included in each group are different. 
     In addition, the server  400  generates new image data including the visual line data of each head mounted display system  1  received in Step S 22  and group data generated in Step S 24  (S 25 ). 
     Subsequently, the server  400  transmits the new image data to each head mounted display system  1  (S 26 ). 
     Until an end request is received, the server  400  continues the process of Steps S 22  to S 26  (S 27 ). 
     The process performed by the head mounted display system  1  in this case is the same as the process described above with reference to  FIG. 9 . In addition, new image data including group data, for example as included in  FIG. 12( a ) , is an image in which identifiers of users can be identified for each group. 
     More specifically, in the example illustrated in  FIG. 12( a ) , users of identifiers C and H are included in Group 1, users of identifiers D, E, and J are included in Group 2, users of identifiers F and K are included in Group 3, users of identifiers A and B are included in Group 4, and users of identifiers G and I are included in Group 5. 
     &lt;&lt;Example in which Users of Different Visual Line Information are Guided&gt;&gt; 
     An example of a process performed when visual lines are guided to a target position in a case in which the visual lines of users are different from the target position will be described with reference to  FIG. 13 .  FIG. 13  is a flowchart illustrating a process performed by the server  400 . 
     First, the server  400  transmits image data dl stored in the storage device  41  to each head mounted display system  1  connected through the network  500  (S 31 ). 
     Thereafter, the server  400  receives visual line data of users viewing the image data dl from each head mounted display system  1  (S 32 ). 
     Next, the server  400  extracts users whose visual lines are located at positions other than the target position (S 33 ). For example, the server  400  extracts users whose visual lines are at positions deviating from the coordinates of the target position by a predetermined distance. At this time, in addition to the visual lines of users, the server  400  may use the behaviors of the users as an extraction condition. 
     The server  400  generates new image data including guide data (S 34 ). 
     Subsequently, the server  400  transmits the new image data to each head mounted display system  1  (S 35 ). 
     Until an end request is received, the server  400  continues the process of Steps S 32  to S 25  (S 26 ). 
     The process performed by the head mounted display system  1  in this case is the same as the process described above with reference to  FIG. 9 . For example, as included in  FIG. 12( b ) , the guided data included in the image data indicates a target position and is a symbol, a mark, or the like. For example, an example of the symbol includes a pointer. In the example illustrated in  FIG. 12( b ) , a portion surrounded by a broken line is the target position. 
       FIGS. 14A to 14C  are other examples of an image in which guide data is displayed. In the example illustrated in  FIG. 14( a ) , a mark F 1  including a target position (a portion of a broken line) and a user&#39;s viewpoint (H portion) is attached to the image based on the guide data. This mark F 1 , as illustrated in  FIGS. 14( b ) and 14( c ) , is gradually decreased with the target position set as the center, thereby guiding the visual lines of users. The shape of the mark F 1  is not limited to the shapes illustrated in  FIGS. 14A to 14C . 
       FIGS. 15A to 15C  are further examples of an image in which guide data is displayed. In the example illustrated in  FIG. 15( a ) , a mark F 2  including a user&#39;s viewpoint (H portion) is attached to the image based on the guide data. This mark F 2  moves from the user&#39;s viewpoint toward a target position (a portion of a broken line) while gradually being enlarged, thereby guiding the visual lines of users.  FIG. 15( b )  is an example of an image that is in the process of the movement of the mark F 2 . In addition,  FIG. 15( c )  is an example of an image in which the mark F 2  is moved to the target position. In  FIG. 15( b ) , a circle of a broken line represents the position of the mark F 2  illustrated in  FIG. 15( a ) . In addition, in  FIG. 15( c ) , a circle of a broken line represents the position of the mark F 2  illustrated in  FIG. 15( a )  and the position of the mark F 2  illustrated in  FIG. 15( b ) . 
     In addition, a symbol or a mark displayed to indicate a target position may blink at a predetermined time interval, or the size thereof may be changed intermittently. When the symbol or the mark blinks or changes size, the target position can be easily perceived by the user. 
     According to the image providing system I of the first embodiment having the configuration described above, when image data is provided for head mounted displays of a plurality of users, the image data generated according to a user&#39;s visual line data can be provided. For example, the image data may include group data according to the visual line data and guide data. In this way, by using the image providing system I, a plurality of users can be managed. 
     Second Embodiment 
     As illustrated in  FIG. 16 , in an image providing system II according to a second embodiment, a head mounted display system  1 X (hereinafter, referred to as a “host terminal  1 X” as is necessary) that is at least one host terminal and a plurality of head mounted display systems  1  ( 1 A to  1 C) that are client systems are connected to a server  400 . 
     In the image providing system II according to the second embodiment, a group can be designated from an input device  23  of the host terminal  1 X. Alternatively, in the image providing system II, a group can be designated from visual line data detected by a detection unit  202  of the host terminal  1 X. In addition, in the image providing system II, user&#39;s visual lines can be guided from the host terminal  1 X. 
     &lt;&lt;Server&gt;&gt; 
     The server  400  of the image providing system II according to the second embodiment has the same configuration as the server  400  described above with reference to  FIG. 2A . In addition, in the image providing system II according to the second embodiment, in the host terminal  1 X, group division and guiding of visual lines of users can be performed. For this reason, the classification unit  403  and the extraction unit  404  of the server  400  are not essential configurations. 
     In addition, a generation unit  402  of the server  400  of the image providing system II can generate new image data including group data and guide data supplied from the head mounted display system  1 . 
     &lt;&lt;Head Mounted Display System&gt;&gt; 
     A second communication control unit  201  of the head mounted display system  1  of the image providing system II according to the second embodiment provides group data and guide data input through an input device  23  of a visual line detecting device  200  for the server  400  through a communication I/F  22  together with visual line data detected by a detection unit  202 . Here, the visual line detecting device  200 X of the host system  1 X and the server  400  may be integrally configured. 
     A process performed by the host terminal  1 X will be described with reference to  FIGS. 16 and 17 .  FIG. 17  is an example of an image displayed by the host terminal  1 X.  FIG. 18  is a flowchart illustrating the process performed by the host terminal  1 X. 
     As illustrated in  FIG. 18 , the host terminal  1 X receives image data from the server  400  (S 41 ). In addition, the host terminal  1 X displays the received image data (S 42 ). 
     Here, before the acquisition of visual line data of users, in the host terminal  1 X, as illustrated in  FIG. 17( a ) , an image not including the visual line data is displayed. In addition, after the acquisition of the visual line data of users, in the host terminal  1 X, as illustrated in  FIG. 17( b ) , an image including the visual line data of users (for example, identifiers of users) is displayed. 
     Thereafter, when designation of a group is input to a displayed image (Yes in S 43 ), the host terminal  1 X transmits a request signal including group data to the server  400  (S 44 ). The request signal requests the generation of image data including group data that is information according to a visual line. Here, the request signal may request the generation of image data for each group. The designation of a group, for example, is input using an input device  23  such as a mouse or a touch panel. More specifically, as illustrated in  FIG. 17( c ) , a group is designated by enclosing identifiers of users by using the input device  23 . Alternatively, for example, the detection unit  202  may detect the visual line of a user using the host terminal  1 X so as to designate a group. More specifically, as illustrated in  FIG. 17( c ) , a user using the host terminal  1 X may view an image displayed on a display unit  121  and moves a visual line so as to enclose identifiers disposed inside the image, thereby designating a group. 
     In addition, when guide data is input for the displayed image through the input device  23  (Yes in S 45 ), the host terminal  1 X transmits a request signal including the guide data to the server  400  (S 46 ). This request signal requests the generation of image data including guide data guiding a visual line. 
     Until an end request is received, the host terminal  1 X continues the process of Steps S 41  to S 46  (S 26 ). 
     According to the image providing system II of the second embodiment having the configuration described above, in a case where image data is provided for head mounted displays of a plurality of users, image data generated according to visual line data of the user can be provided. For example, in the image data, group data according to the visual line data and guide data may be included. In this way, a plurality of users can be managed using the image providing system II. 
     The technique relating to the visual line detection according to the embodiment described above is an example, and the visual line detecting method using the head mounted display  100  and the visual line detecting device  200  is not limited thereto. 
     First, in the embodiment described above, while an example is illustrated in which a plurality of infrared light sources emitting near-infrared light as non-visible light are arranged, the technique for emitting near-infrared light to the user&#39;s eyes is not limited thereto. For example, in pixels configuring the image display device  108  of the head mounted display  100 , pixels each having a sub pixel emitting near-infrared light may be disposed, and near-infrared light may be emitted to the user&#39;s eyes by selectively causing sub pixels emitting the near-infrared light to emit light. In addition, alternatively, a configuration may be employed in which a retina projection display is disposed in the head mounted display  100  instead of the image display device  108 , and by including pixels emitting light in a near-infrared light color inside an image that is displayed by the retina projection display and is projected to user&#39;s retinas, the emission of near-infrared light is realized. Either in the case of the image display device  108  or in the case of the retina projection display, sub pixels emitting near-infrared light may be regularly changed. 
     In addition, the algorithm for visual line detection represented in the embodiment described above is not limited to the technique represented in the embodiment described above, but any other algorithm realizing visual line detection may be used. 
     In the embodiment described above, each process of the image providing system has been described to be realized as the CPUs of the server  400 , the head mounted display  100 , and the visual line detecting device  200  execute an image providing program and the like. On the other hand, in each of the server  400 , the head mounted display  100 , and the visual line detecting device  200 , instead of the CPU, each process may be realized by a logic circuit (hardware) or a dedicated circuit formed in an integrated circuit (IC) chip, large scale integration (LSI), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or the like. In addition, such a circuit may be realized by one or a plurality of integrated circuits, and the functions of a plurality of functional units illustrated in the embodiment described above may be realized by one integrated circuit. The LSI may be also referred to as VLSI, super LSI, ultra LSI, or the like depending on differences in the degree of integration. 
     In other words, as illustrated in  FIG. 19A , the server  400  may be configured by: a communication I/F  42 ; a control circuit  40   a  including a first communication control circuit  401   a , a generation circuit  402   a , a classification circuit  403   a , and an extraction circuit  404   a ; and a storage device  41  storing image data  411  and an image providing program P 1 . The first communication control circuit  401   a , the generation circuit  402   a , the classification circuit  403   a , and the extraction circuit  404   a  are controlled by the image providing program P 1 . The function of each thereof is similar to that of each unit having the same name represented in the embodiment described above. 
     In addition, as illustrated in  FIG. 19B , the head mounted display  100  may be configured by a communication I/F  110 , a third communication control circuit  118   a , a display circuit  121   a , an infrared light emitting circuit  122   a , an image processing circuit  123   a , and an imaging circuit  124   a . The function of each thereof is similar to that of each unit having the same name represented in the embodiment described above. 
     Furthermore, as illustrated in  FIG. 19B , the visual line detecting device  200  may be configured: by a control circuit  20   a  including a second communication control circuit  201   a , a detection circuit  202   a , an image generating circuit  203   a , and an image output circuit  204   a ; a storage device  21  storing a visual detecting program P 2 ; a communication I/F  22 ; an input device  23 ; and an output device  24 . The second communication control circuit  201   a , the detection circuit  202   a , the image generating circuit  203   a , and the image output circuit  204   a  are controlled by the visual line detecting program P 2 . The function of each thereof is similar to that of each unit having the same name represented in the embodiment described above. 
     In addition, as each of the storage devices  21  and  41  described above, “a medium of a non-temporary type”, for example, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like may be used. The search program described above may be supplied to the processor described above through an arbitrary transmission medium (a communication network, a broadcast wave, or the like) capable of transmitting the search program. The present invention can be also realized by the form of a data signal embedded in a carrier wave in which the video displaying program described above is embodied through electronic transmission. 
     In addition, the program, for example, may be implemented using a script language such as ActionScript, JavaScript (registered trademark), Python, or Ruby, a complier language such as a C language, C++, C#, Objective-C, or Java (registered trademark), an assembly language, a register transfer level (RTL), or the like. 
     Third Embodiment 
       FIG. 20  is a block diagram illustrating the configuration of a head mounted display system  1   b  according to a third embodiment. As illustrated in  FIG. 20 , a head mounted display  100  of the head mounted display system  1   b  includes a communication interface (I/F)  110 , a communication control unit  118 , a display unit  121 , an infrared ray emitting unit  122 , an image processing unit  123 , and an imaging unit  124 . 
     The communication control unit  118  controls communication with a visual line detecting device  200  through the communication I/F  110 . The communication control unit  118  transmits image data used for visual line detection, which is transmitted from the imaging unit  124  or the image processing unit  123 , to the visual line detecting device  200 . In addition, the communication control unit  118  delivers image data or a marker image transmitted from the visual line detecting device  200  to the display unit  121 . The image data, for example, is data used for displaying a test. In addition, the image data may be a parallax image pair formed by a right-eye parallax image and a left-eye parallax image used for displaying a three-dimensional image. 
     The display unit  121  has a function for displaying the image data delivered from the communication control unit  118  on an image display device  108 . The display unit  121  displays a test image as image data. In addition, the display unit  121  displays a marker image output from the video generating unit  222  at designated coordinates of the image display device  108 . 
     The infrared ray emitting unit  122  emits infrared light to the right eye or the left eye of a user by controlling an infrared light source  103 . 
     The image processing unit  123  performs image processing for an image captured by the imaging unit  124  as is necessary and delivers the processed image to the communication control unit  118 . 
     The imaging unit  124  captures an image including near-infrared light reflected by each eye by using a camera  116 . In addition, the imaging unit  124  captures an image including the eye of a user gazing at the marker image displayed on the image display device  108 . The imaging unit  124  delivers the images acquired through the capturing process to the communication control unit  118  or the image processing unit  123 . 
     As illustrated in  FIG. 20 , the visual line detecting device  200  is an information processing apparatus including a central processing unit (CPU)  20 , a storage device  21  storing the image data  211  and the data generating program P 3 , a communication I/F  22 , an input device  23  such as operation buttons, a keyboard, or a touch panel, and an output device  24  such as a display or a printer. In the visual line detecting device  200 , as the data generating program P 3  stored in the storage device  21  is executed, the CPU  20  performs processes as a communication control unit  201   b , a detection unit  202   b , an analysis unit  203   b , a timer  204   b , an operation acquiring unit  205   b , an attribute acquiring unit  206   b , a generation unit  207   b , and an output unit  208   b.    
     The image data  211  is data to be displayed on the head mounted display  100 . The image data  211  may be either a two-dimensional image or a three-dimensional image. In addition, the image data  211  may be either a still image or a moving image. 
     For example, the image data  211  is moving image data of a video game. When the image data  211  is an image of a video game, an image to be displayed is changed according to an operation signal input by a user. In addition, for example, the image data  211  is moving image data of a movie. The image data  211  may be purchased from a connected external server apparatus or the like (not illustrated in the drawing) in accordance with a user&#39;s operation. 
     The communication control unit  201   b  controls communication with the head mounted display  100  through the communication I/F  22 . 
     The detection unit  202   b  detects a user&#39;s visual line and generates visual line data. 
     The analysis unit  203   b  analyzes a user&#39;s visual line by using the visual line data. Here, the analysis unit  203   b  uses data input from the timer  204   b , the operation acquiring unit  205   b , and the attribute acquiring unit  206   b  as is necessary. 
     When the image data  211  is moving image data of a game, the timer  204   b  measures a user&#39;s play time of the game. In addition, the timer  204   b  outputs measured time data to the analysis unit  203   b . For example, the timer  204   b  measures an attainment time from the start of the game to the end (game clear). Here, in a case where a user plays the same game a plurality of number of times, the timer  204   b  measures an attainment time from the start of the game of the first time to the end. In addition, for example, the timer  204   b  measures a total play time of the game. Here, in a case where a user plays the same game a plurality of number of times, the timer  204   b  measures a sum of play times of a plurality of number of times as a total play time (total time). 
     The operation acquiring unit  205   b  receives various operation signals input relating to the display of the image data  211 . In addition, the operation acquiring unit  205   b  outputs data relating to an operation signal to the analysis unit  203   b . For example, when the image data  211  is data of a game, information of a user&#39;s operation performed in the game is acquired. Here, the user&#39;s operation may be an operation according to the movement of a visual line that can be detected by the detection unit  202   b  in addition to an operation input using an input button or an operation according to the input of an audio signal. 
     The attribute acquiring unit  206   b  acquires attribute data of a user using the image data  211 . In addition, the attribute acquiring unit  206   b  outputs the acquired data to the analysis unit  203   b . The attribute data, for example, is data relating to user&#39;s sex, age, occupation, and the like. For example, in a case where the head mounted display system  1  is connected to a management server or the like, and the user is registered in the management server, the attribute data can be acquired from the registration information. Alternatively, the attribute data of the user may be stored in the storage device  21  of the visual line detecting device  200 . 
     The generation unit  207   b  generates visualization data including a result of the detection acquired by the detection unit  202   b  and a result of the analysis acquired by the analysis unit  203   b . For example, in a case where a specific visual line is analyzed by the analysis unit  203   b , the generation unit  207   b  generates visualization data including an image and data (a point representing coordinates or a trajectory of a visual line) specified by a visual line corresponding to the image. As the visualization data, heat map data, data representing a result of the analysis as a graph, or the like may be considered. Here, when the image data is moving image data, the visualization data may include a time axis display section specifying a relation between a user′ viewpoint in an image and a time axis of one image in the image data. In addition, when the result of the analysis acquired by the analysis unit can be represented as a bar graph or the like, data including the bar graph is generated as the visualization data. 
     The output unit  208   b  outputs the visualization data generated by the generation unit  207   b  to the output device  24  and the like. 
     In addition, among the units of the visual line detecting device  200  described above, the analysis unit  203   b , the timer  204   b , the operation acquiring unit  205   b , the attribute acquiring unit  206   b , and the generation unit  207   b  may be realized by an information processing apparatus such as an external server or the like. In a case where such processing units  203   b  to  207   b  are realized by an external information processing apparatus, an acquisition unit acquiring visual line data detected by the detection unit  202   b  of the head mounted display system  1  is included in the information processing apparatus, and the analysis unit  203   b  performs a data analyzing process by using the visual line data acquired by the acquisition unit. 
     &lt;&lt;Visualization Data Generating Process  1 &gt;&gt; 
     A process performed in a case where visualization data is generated and output by the head mounted display system  1   b  will be described with reference to a flowchart illustrated in  FIG. 21( a ) . 
     The head mounted display system  1   b , first, displays target image data  211  (S 51 ). 
     When an image is displayed, the head mounted display system  1   b  detects a visual line of a user viewing the displayed image data  211  (S 52 ). 
     When the visual line of a user is detected, the head mounted display system  1   b  analyzes the detected visual line of the user (S 53 ). 
     When the visual line is analyzed, the head mounted display system  1   b  generates visualization data (S 54 ). 
     The head mounted display system  1   b  outputs the generated visualization data (S 55 ). 
     Here,  FIG. 20  illustrates an example in which one head mounted display  100  is connected to one visual line detecting device  200 . However, a plurality of head mounted displays  100  may be connected to one visual line detecting device  200 . In such a case, in order to display the image data  211  on each head mounted display  100  and detect visual line data from each user, the process of Steps S 01  and S 02  is repeated a plurality of number of times. In addition, the process of Steps S 53  to S 55  is repeated using the visual line data detected from a plurality of users. 
       FIGS. 22A and 22B  are examples of visualization data generated by using visual line data of a plurality of users in a case where a certain still image is displayed for a predetermined time. The example illustrated in  FIG. 22( a )  illustrates visualization data W 1  including the trajectories S 1  to S 4  of the visual lines of the users. The example illustrated in  FIG. 22( b )  illustrates visualization data W 2  including bar graphs representing positions at which users gaze for a predetermined time or more. 
       FIGS. 23A to 23C  illustrate an example of visualization data generated using visual line data of users in a case where a moving image is displayed.  FIGS. 23( a ) and 23( b )  illustrate visualization data W 3  including a time slider T representing the status of progress of the moving image. Regarding  FIGS. 23( a ) and 23( b ) , an image of  FIG. 23( a )  is displayed first, and thereafter, an image of  FIG. 23( b )  is displayed. Here, in  FIGS. 23( a ) and 23( b ) , black circle portions are the positions of users&#39; visual lines. 
     &lt;&lt;Visualization Data Generating Process  2 &gt;&gt; 
     A process performed in a case where visualization data is generated and output by the head mounted display system  1   b  will be described with reference to a flowchart illustrated in  FIG. 21( b ) . 
     The head mounted display system  1   b  acquires visual line data of users (S 61 ). 
     In addition, when the visual line data of the users is acquired, the head mounted display system  1   b  analyzes the acquired visual lines of the users (S 62 ). 
     When the visual lines are analyzed, the head mounted display system  1   b  generates visualization data (S 63 ). 
     The head mounted display system  1   b  outputs the generated visualization data (S 64 ). 
     The process of these Steps S 11  to S 14  may be performed not by the head mounted display system  1   b  but by an information processing apparatus such as an external server including an acquisition unit acquiring a result detected by the detection unit  202   b , the analysis unit  203   b , the timer  204   b , the operation acquiring unit  205   b , the attribute acquiring unit  206   b , the generation unit  207   b , and the like. 
     When the image data  211  is data of a video game, the analysis unit  203   b , for example, can analyze the following contents (1-1) to (1-6). 
     (1-1) User&#39;s Viewpoint Until Visual Line Move to Target Position 
     The trajectory of a user&#39;s visual line until the user&#39;s visual line moves to a target position and a time required for the user&#39;s visual line to move to the target position are analyzed. The time required for the user&#39;s visual line to move to the target position, for example, can be specified based on a time input from the timer  204   b . In this way, for example, the degree of easiness in finding a target position in a displayed image can be acquired. In addition, the generation unit  207   b  generates a graph of a time required for each user&#39;s visual line to arrive at a target position as visualization data. 
     In addition, by collecting and analyzing the data of a plurality of users, the analysis unit  203   b  can analyze the tendency of image data for which a user can easily find a target position. Furthermore, by analyzing the image data in combination with user&#39;s attributes, the analysis unit  203   b  can analyze a time required for each visual line to move to a target position and the tendency of a user&#39;s attribute. The user&#39;s attributes are input from the attribute acquiring unit  206   b.    
     (1-2) Viewpoint of User Whose Visual Line Deviate from Target Position 
     In a case where the user&#39;s visual line is not present at a target position, the analysis unit  203   b  analyzes the coordinates (viewpoint) of the user&#39;s visual line at that time point. In this way, in a displayed image, a place by which the user is attracted and led astray can be specified. For example, the generation unit  207   b  generates the coordinates of the user&#39;s viewpoint as the visualization data. 
     In addition, by collecting and analyzing the data of a plurality of users, the analysis unit  203   b  can analyze the tendency of image data for which a user is easily led astray. Furthermore, by analyzing the image data in combination with the user&#39;s attributes, the analysis unit  203   b  can analyze the tendency of user&#39;s attributes for which the user is easily led astray. The user&#39;s attributes are input from the attribute acquiring unit  206   b.    
     (1-3) Reason for Case where Visual Line Deviates from Target Position 
     In a case where a user&#39;s visual line is not present at a target position, the analysis unit  203   b  acquires the trajectory of the user&#39;s visual line in images displayed for a predetermined time until reaching the state. In this way, in images displayed until reaching a certain state, the reason of an object by which the user is attracted and led astray can be predicted. For example, the generation unit  207   b  generates the trajectory of a user&#39;s viewpoint as the visualization data. 
     In addition, by collecting and analyzing the data of trajectories of visual lines of a plurality of users, the analysis unit  203   b  can analyze image data for which a user is easily led astray. Furthermore, by analyzing the image data in combination with user&#39;s attributes, the analysis unit  203   b  can analyze the tendency of users who are easily less astray. 
     (1-4) User&#39;s Position of Interest on Initial Screen 
     The analysis unit  203   b  detects the coordinates of a user&#39;s visual line on the initial screen of a game. In this way, the analysis unit  203   b  analyzes a place on the initial screen to which a user gives attention. In other words, by analyzing a place to which the user gives attention on the initial screen, the analysis unit  203   b  can perceive a place by which the user is attracted on the initial screen. For example, the generation unit  207   b  generates the coordinates of the user&#39;s viewpoint as the visualization data. 
     In addition, by collecting and analyzing the visual line data of a plurality of users, the analysis unit  203   b  can analyze an image configuration by which many users are attracted. Furthermore, by analyzing the image configuration in combination with user&#39;s attributes, the analysis unit  203   b  can analyze the tendency of users attracted by each image configuration. 
     In addition, by analyzing the image configuration in combination with a user&#39;s total play time, the analysis unit  203   b  can analyze data by which the user is easily attracted and the tendency of degree of user&#39;s interest in the game. For example, a user having a long total play time is frequently a user having a preference for a target game, and a user having a short total play time is frequently a user having no interest in the target game. Thus, for example, by analyzing data by which a user is attracted and the play time of the user in combination with each other, a difference in the viewpoints of a user having interest in the game and a user having no interest in the game can be analyzed. The user&#39;s total play time is input from the timer  204   b.    
     (1-5) Tendency of User Performing Specific Operation 
     The analysis unit  203   b  detects the coordinates (viewpoint) of the visual line of a user performing a specific operation in a game. In this way, the interest and concern of a user performing each operation can be specified. This operation may be either an operation relating to the play of the game or any other operation. The analysis unit  203   b  receives data relating to the execution of an operation from the operation acquiring unit  205   b . For example, the generation unit  207   b  generates the coordinates of the viewpoint of a user as the visualization data. 
     For example, by checking an operation relating to the play of a game and the user&#39;s viewpoint at the time of performing the operation, a relation between the user&#39;s operation and the visual line can be acquired. As the user&#39;s operation, for example, in the case of a game for acquiring a score, the visual line of a user performing an operation acquiring a high score may be considered. In addition, as an operation other than the play of the game, for example, there is an operation of purchasing a content in the game. For example, by analyzing a certain point in which a user purchasing a content has interest for purchasing the content, a game development for which a user purchases a content and an image configuration preferred by a user purchasing many contents can be specified. 
     In addition, by collecting and analyzing the data of visual lines of a plurality of users and data relating to the execution of an operation, the analysis unit  203   b  can analyze a relation between a user&#39;s operation and image data. Furthermore, by analyzing the data in combination with user&#39;s attributes, the analysis unit  203   b  can analyze the tendency of users performing each operation. 
     In addition, by analyzing the data in combination with a user&#39;s total play time, the analysis unit  203   b  can analyze a user performing a specific operation and the tendency of degree of user&#39;s interest in a user game. For example, a user having a long total play time is frequently a user preferring a target game, and a user having a short total play time is frequently a user having no interest in the target game. Thus, for example, a relation between the execution of a specific operation and a user having interest in the game and a user having no interest in the game can be analyzed. 
     (1-6) User&#39;s Level 
     In the case of a game in which a user&#39;s level can be acquired from a score acquired in the game or the like for the analysis of (1) to (4), the analysis unit  203   b  may consider the level. In other words, for each user&#39;s level, a viewpoint of a user having a visual line deviating from a target position, a reason for a case where the visual line deviates from the target position, a user&#39;s position of interest on an initial screen, and the tendency of users performing a specific operation can be analyzed. 
     When the image data  211  is data of a movie, for example, the following contents (2-1) to (2-3) can be analyzed. 
     (2-1) User&#39;s Position of Interest 
     The analysis unit  203   b  detects the coordinates (viewpoint) of a user&#39;s visual line inside an image. In this way, on a display image, a place attracted by the user can be specified. In addition, by collecting and analyzing the data of a plurality of users, the configuration of an image attracted by a plurality of users can be specified. 
     (2-2) User&#39;s Attribute 
     The analysis unit  203   b  may analyze user&#39;s attributes together with a user&#39;s position of interest of (2-1) described above. In this way, the tendency of a user&#39;s attribute preferring the configuration of each image can be analyzed altogether as well. The user&#39;s attributes are input from the attribute acquiring unit  206   b.    
     (2-3) Purchase History of Content 
     The analysis unit  203   b  may analyze a user&#39;s purchase history of a movie content together with the user&#39;s position of interest of (2-1) described above and the user&#39;s attributes of (2-2) described above. Examples of the purchase history include the price of a movie content and, in the case of an online purchase, purchase date and time, and the like. In this way, the tendency of purchases of a content can be analyzed altogether. 
     In this way, the analysis unit  203   b  analyzes the viewpoint of a specific user and the tendency of a plurality of viewpoints of users. 
     Fourth Embodiment 
       FIG. 24  is a block diagram of a head mounted display  100  and a visual line detecting device  200  of a video display system  1   c  according to a fourth embodiment. 
     The head mounted display  100  includes a control unit (CPU)  150 , a memory  151 , an infrared ray emitting unit  122 , a display unit  121 , an imaging unit  124 , an image processing unit  123 , and an inclination detecting unit  156  in addition to an infrared light source  103 , an image display device  108  (hereinafter, referred to as a “display  108 ”), a camera  116 , and a communication I/F  110  as electric circuit components. 
     Meanwhile, the visual line detecting device  200  includes a control unit (CPU)  20 , a storage device  21 , a communication I/F  22 , a visual line detecting unit  213 , a video generating unit  214 , and an audio generating unit  215 . 
     The communication I/F  110  is a communication interface having a function for communicating with the communication I/F  22  of the visual line detecting device  200 . The communication I/F  110  communicates with the communication I/F  22  through wired communication or wireless communication. Examples of the communication standard that can be used are as described above. The communication I/F  110  transmits video data used for visual line detection, which is transmitted from the imaging unit  124  or the image processing unit  123 , to the communication I/F  22 . In addition, the communication I/F  110  delivers video data and a marker image transmitted from the visual line detecting device  200  to the display unit  121 . The video data transmitted from the visual line detecting device  200  is data used for displaying a moving image including a video of one or more persons or the like such as a PV as an example. In addition, the video data may be a parallax video pair configured by a right-eye parallax video and a left-eye parallax video used for displaying a three-dimensional video. 
     The control unit  140  controls the electric circuit components described above by using a program stored in the memory  151 . Thus, the control unit  140  of the head mounted display  100  may execute a program realizing a visual line detecting function in accordance with a program stored in the memory  151 . 
     The memory  151  can temporarily store image data captured by the camera  116  and the like as is necessary in addition to the storing of the program used for the function of the head mounted display  100  described above. 
     The infrared ray emitting unit  122  emits near-infrared light to the right eye or the left eye of the user  300  from the infrared light source  103  by controlling the lighting state of the infrared light source  103 . 
     The display unit  121  has a function for displaying video data delivered by the communication I/F  110  on the display  108 . The display unit  121  displays a video including one or more persons such as a promotion video (PV) of an idol group or the like, a live video of various concerts or the like, and a lecture video of a talk show or the like. In addition, the display unit  121  displays a marker image output by the video generating unit  214  at designated coordinates on the display unit  121 . 
     The imaging unit  124  captures an image including near-infrared light reflected by the left and right eyes of the user  300  by using the camera  116 . In addition, the imaging unit  124  captures a bright spot image and an anterior ocular segment image of the user  300  gazing at the marker image displayed on the display  108  to be described later. The imaging unit  124  delivers image data acquired through the capturing process to the communication I/F  110  or the image processing unit  123 . 
     The image processing unit  123  performs image processing for the image captured by the imaging unit  124  as is necessary and delivers the processed image to the communication I/F  110 . 
     The inclination detecting unit  156  calculates the inclination of the head part of the user  300  as the inclination of the head mounted display  100 , for example, based on a detection signal supplied from an inclination sensor  157  such as an acceleration sensor or a gyro sensor. The inclination detecting unit  156  sequentially calculates the inclinations of the head mounted displays  100  and delivers inclination information that is a result of the calculation to the communication I/F  110 . 
     The control unit (CPU)  210  performs the visual line detection described above by using a program stored in the storage device  21 . The control unit  210  controls the video generating unit  214  and the audio generating unit  215  in accordance with a program stored in the storage device  21 . 
     The storage device  21  is a recording medium storing various programs and data that are required for the operation of the visual line detecting device  200 . The storage device  21 , for example, can be realized by a hard disc drive (HDD), a solid state drive (SSD), or the like. The storage device  21  stores information of a position on the outer surface of the display  108  that corresponds to each person appearing in a video corresponding to the video data and audio information of each person. 
     The communication I/F  22  is a communication interface having a function for communicating with the communication I/F  110  of the head mounted display  100 . As described above, the communication I/F  22  communicates with the communication I/F  110  through wired communication or wireless communication. The communication I/F  22  transmits video data used for displaying a video including one or more persons, a marker image used for calibration, and the like, which are delivered by the video generating unit  214 , to the head mounted display  100 . In addition, the communication I/F  22  delivers the bright spot image of a user  300  gazing at the marker image captured by the imaging unit  124 , which is delivered by the head mounted display  100 , the anterior ocular segment image of a user  300  viewing a video displayed based on the video data output by the video generating unit  214 , and the inclination information calculated by the inclination detecting unit  156  to the visual line detecting unit  213 . In addition, the communication I/F  22  may be configured to access an external network (for example, the Internet), acquire video information of a moving image web site designated by the video generating unit  214 , and deliver the acquired video information to the video generating unit  214 . Furthermore, the communication I/F  22  transmits audio information delivered by the audio generating unit  215  to the headphones  170  directly or through the communication I/F  110 . 
     The visual line detecting unit  213  detects a visual line direction of the user  300  by analyzing the anterior ocular segment image captured by the camera  116 . More specifically, the visual line detecting unit  213  receives video data used for detecting the visual line of the right eye of the user  300  from the communication I/F  22  and detects the visual line direction of the right eye of the user  300 . The visual line detecting unit  213 , by using a technique to be described later, calculates a right-eye visual line vector representing the visual line direction of the right eye of the user  300 . Similarly, the visual line detecting unit  213  receives video data used for detecting the visual line of the left eye of the user  300  from the communication I/F  22  and calculates a left-eye visual line vector representing the visual line direction of the left eye of the user  300 . Then, the visual line detecting unit  213  specifies a portion of a video displayed on the display unit  121  at which the user  300  gazes. The visual line detecting unit  213  delivers the specified gazing point to the video generating unit  214 . 
     The video generating unit  214  generates video data to be displayed on the display unit  121  of the head mounted display  100  and delivers the generated video data to the communication I/F  22 . The video generating unit  214  generates marker images used for the calibration for visual line detection and delivers the generated marker images to the communication I/F  22  together with the display coordinate position thereof to be transmitted to the head mounted display  100 . In addition, the video generating unit  214  generates video data of which the display form of the video is changed according to the visual line direction of the user  300  that is detected by the visual line detecting unit  213 . The method of changing the display form of a video will be described later in detail. The video generating unit  214  determines whether or not the user  300  gazes at one specific person based on the gazing point delivered by the visual line detecting unit  213  and, in a case where the user gazes at the one specific person, specifies the one person. 
     In a case where one or more persons are present in a video output by the display  108  in the visual line direction of the user  300  that is detected by the visual line detecting unit  213 , the audio generating unit  215  specifies the person and generates audio data such that the output state of a voice output from the headphones  170  in correspondence with the specified person is different from the output state of the other voices so as to be identifiable for the user  300 . 
     For example, the audio generating unit  215  generates audio data to be identifiable for the user  300  by increasing the volume of the sound of the specified person or decreasing the volume of the voices of persons other than the specified person such that the volume of the sound the specified person is larger than that of the other sounds. 
     In addition, the audio generating unit  215  may give an additional function of modulating, increasing (decreasing) a modulation tempo, or enhancing the sound to the audio data in addition to the increasing of the volume of the sound of the specified person to be larger than the volume of the other voices. The audio generating unit  215  may give an additional function of causing music of a musical performance or the like to be mute during an interlude of a pop song music video (PV) or the like to the audio data. In addition, while details will be described later, in a case where music is caused to be mute during an interlude by the audio generating unit  215 , the video generating unit  214  may give an additional function of slowing down the video so as to slowly view the choreography of a specified person or the like. 
     The video generating unit  214  may generate video data such that the user can more easily gaze at a video of a predetermined area including at least a part of a specified person than a video of an area other than the predetermined area based on the visual line direction of the user  300 . For example, an additional function of highlighting such as application of smoke to a portion other than the specified person, moving the video data such that the specified person is positioned at the center of the display  108 , or zooming up a part of the specified person such as a face or an instrument may be given. In addition, for example, in promotion videos of recent years, for the same musical piece, one musical piece is configured by combining videos a plurality of patterns in which characters, a film set or a filming location (regardless of being natural or artificial), choreography, costumes, or the like are different from each other. For this reason, there is also a case where a different video pattern can be selected for the same melody part. For this reason, for example, an additional function of performing switching to a video pattern in which a specified person appears more frequently or following a specified person when the specified person moves may be given. 
     &lt;&lt;Data&gt;&gt; 
     Here, specific video data will be described. For example, generally, in a promotion video of an idol group or the like, video capturing and generation and audio (singing and playing) recording are separately performed. 
     At this time, singing is individually performed regardless whether the part is a part in which all the members sing or a part in which an individual sings (solo part). Accordingly, a sound and playing can be easily specified for each person and thus can be used as known information. 
     Meanwhile, also for a video, in an outdoor place or a studio, there are a case where all the members are imaged and a case where an individual is imaged, and, finally, image processing such as background processing is usually performed. Thus, by combining (linking) the video with an audio, a relation between the video and the time axis can be also used as known information. In addition, also when each person moves according to choreography or the like on the screen, for a screen size (aspect ratio) set in advance, for example, a position according to the time axis using a face as the reference can be easily used as known information. 
     In this way, on the display screen of the display  108  described above, relating to each person (character) on a video, a sound (playing) and a position are embedded in video data in association with the time axis, or performer data of a table system corresponding to the video data can be formed. 
     Accordingly, when the visual line position of the user  300  is detected by the visual line detecting unit  213 , the control unit  210  can specify a person in the video who is intensively viewed by the user  300  from the XY coordinates of the visual line position and a time table. 
     &lt;&lt;Operation&gt;&gt; 
     Next, the operation of the video display system  1   c  will be described with reference to a flowchart illustrated in  FIG. 25 . In the following description, the control unit  210  of the visual line detecting device  200  is assumed to transmit video data including audio data from the communication I/F  22  to the communication I/F  110 . 
     (Step S 71 ) 
     In Step S 71 , the control unit  140 , by operating the display unit  121  and the audio output unit  132 , outputs a video to the display  108  so as to be displayed thereon and outputs an audio from the audio output unit  132  of the headphones  170 , and the process proceeds to Step S 72 . 
     (Step S 72 ) 
     In Step S 72 , the control unit  210 , based on image data captured by the camera  116  detects a gazing point (visual line position) of the user  300  on the display  108  by using the visual line detecting unit  213  and specifies the position. 
     (Step S 73 ) 
     In Step S 73 , the control unit  210  determines whether or not the user  300  gazes at one specific person. More specifically, the control unit  210  determines whether or not the user  300  gazes at one specific person, also in a case where a person in the video moves or the like in a time series, based on whether or not a change in the XY coordinate axis at a detected fixation point changing in the time axis coincides with an XY coordinate axis on the video following the time table for a predetermined time (for example, two seconds) with an XY coordinate axis that is initially specified used as a base point. In a case where the control unit  210  determines that the user gazes at one specific person (Yes), the process proceeds to Step S 4 . On the other hand, in a case where the control unit  210  determines that the user does not gaze at one specific person (No), the process proceeds to Step S 78 . In addition, also in a case where one specific person does not move, the specifying sequence described above is the same. 
     (Step S 74 ) 
     In Step S 74 , the control unit  210  specifies a person at whom the user  300  gazes, and the process proceeds to Step S 75 . 
     (Step S 75 ) 
     In Step S 75 , the control unit  210  specifies the audio data of the specified person, and the process proceeds to Step S 76 . 
     (Step S 76 ) 
     In Step S 76 , the control unit  210  causes the audio generating unit  215  to generate audio data of the specified person and audio data of the other persons (a musical performance may be either included or excluded) and transmits new audio data after the generation from the communication I/F  22  to the communication I/F  110 , and the process proceeds to Step S 7 . In this way, for example, the audio data is output from the headphones  170  in a state in which the volume of the singing voice of the person at whom the user  300  gazes is higher than that of the other persons as a result. In addition, the audio generating unit  215  enables the user  300  to easily identify the singing of the one specified person by configuring the voice of the specified person to stand out from the voices of the other persons by increasing only the volume of the singing voice of a person at whom the user  300  gazes or, to the contrary, decreasing the volume of the singing voices of persons other than the person at whom the user  300  gazes. 
     (Step S 77 ) 
     In Step S 77 , actually, in parallel with the routine of Step S 76  described above, the control unit  210  causes the video generating unit  214  to generate new video data such that the person at whom the user  300  gazes can be easily identified and transmits the new video data after the generation from the communication I/F  22  to the communication I/F  110 , and the process proceeds to Step S 7 . In this way, on the display  108 , for example, display is performed from a normal video display state illustrated in  FIG. 26 , as illustrated in  FIG. 27 , to a state in which the video of the specified person (for example, a girl singing at the center position) is maintained as it is, but the videos of the other persons disposed on the periphery thereof are veiled. In other words, the video generating unit  214  performs an emphasizing process in which video data is newly generated such that the user can gaze at the video of a predetermined area (the girl positioned at the center) more easily than the videos of areas other than the predetermined area. 
     (Step S 78 ) 
     In Step S 78 , the control unit  210  determines whether or not the reproduction of the video data has ended. In a case where the generation of the video data is determined to have ended (Yes), the control unit  210  ends this routine. On the other hand, in a case where the generation of the video data is determined not to have ended (No), the control unit  210  loops to Step S 2 , and thereafter, each routine described above is repeated until the reproduction of the video data ends. Accordingly, for example, in a case where the user  300  desires to stop the video output that is in the emphasized state, by only stopping to gaze at the specific person at whom the user has gazed, it is not determined that the user gazes at one specific person (No in Step S 73 ), and the emphasized display and the audio control are stopped. 
     &lt;Summary&gt; 
     In this way, the video display system  1   c , by using the audio generating unit  215 , in a case where one or more persons are present in a video output from the display  108  in the visual line direction of the user  300  that is detected by the visual line detecting unit  213 , specifies the person and generates audio data such that the output state of a voice (including instrument playing and the like) output from the audio output unit  132  in correspondence with the specified person is different from the output state of the other voices so as to be identifiable for the user  300 . 
     For example, in an idol group of a taste, the volume of the singing voice of a recommended member can be configured to be higher than that of the other members as a result such that the singing voice of the recommended member is distinguished more than that of the other members. 
     In this way, the user  300  can easily recognize a sound of the singing voice (part) of the recommended member and thus can enjoy viewing of a promotion video. 
     Here, the specific person is not limited to a member of an idol group or the like, and a player of a backband in a live video of a concert or the like may be set as a target. 
     In such a case, by specifying the player and raising the volume of the play sound (for example, the sound of a main guitar or the sound of a bass guitar), the audio data can be provided for a study on a way of playing and arrangements. 
     At this time, as in the production of the promotion video described above, also in a case where a video and an audio are recorded in the same period instead of separately recording a video and an audio, when a used microphone can be specified at the time of editing the video, the video and the audio can be easily associated with each other. In addition, for example, also in a case where a microphone is not used, since there is a natural frequency or the like in an instrument or a sound, by configuring a person and a sample voice (codec or the like) as a database by using a table system, a person included in the video can be associated with a voice. 
     Furthermore, all the videos in which a plurality of persons appear, for example, all the videos of various plays and operas or various lectures such as talk shows in which a plurality of characters are included can be applied as the video data, and it is particularly useful in a case where voices are mixed. 
     In this way, the output can be changed according to a practical use form, and thus, the versatility can be improved. 
     Here, as techniques for improving the identifying of a voice performed by the user  300  in the audio generating unit  215 , there are a technique of raising the volume of the voice of a specific person, a technique of lowering the volume of voices of the other persons with the volume of the voice of the specific person being maintained as it is, and the like. 
     In addition, the audio generating unit  215  may add an additional function of applying modulation partially or wholly, changing the tempo, or enhancing a voice in a state in which the volume of the voice of such a specific person is higher than that of the other persons as a result. 
     Furthermore, in a case where there is an interlude as in a pop song, the audio generating unit  215  may cause the sound (an instrumental sound, or the like) to be mute during the interlude. Accordingly, such a function can be used also in a case where the choreography of a specific person is to be memorized together with video incorporation such as slowly reproducing a choreography (dance) video of the specific person or the like by using the function of the video generating unit  214 . 
     In addition, in a case where the video generating unit  214  is used together in addition to the audio control performed by the audio generating unit  215 , for example, the display form may be changed such that the user can more easily gaze at the video of a predetermined area including at least a part of a person specified based on the visual line direction of the user  300 , which is detected by the visual line detecting unit  213 , than the video of an area other than the predetermined area. 
     As specific examples of a case in which the video generating unit  214  is used together in addition to the audio control performed by the audio generating unit  215 , in addition to a form in which the whole specific person as a predetermined area has a display form emphasized more than the other area as illustrated in  FIG. 7  described above, there are a form in which, in a case where the video of a specific person is not displayed near the center on the screen, the specific person is moved to a position near the center on the screen, a form in which the face of a specific person or an instrument (an appearance of playing or the like) held by an instrument player is zoomed up, a form in which, in a case where a plurality of video patterns are present for the same music, switching to video data (camera) in which the specific person appears is performed. 
     &lt;Supplement&gt; 
     In addition, the video display system is not limited to the embodiments described above but may be realized by using the other techniques. Hereinafter, examples of the other techniques will be described. 
     (1) In the embodiments described above, while a video such as a promotion video or a live video is used, and an example of a video in a real space including a combined use is illustrated, a case where a similar person, instrument, music, or the like is displayed in a virtual reality space may be applied.
 
(2) In the embodiments described above, while an example has been illustrated in which the volume of the voice of a specific person is higher than that of the other voices as a result, for example, in a case where the specific person is not a so-called main vocal, the sound of the specific person may be interchanged with the sound of the main vocal to be like a main vocal.
 
(3) In the embodiments described above, in order to detect the visual line of the user  300 , as a technique for imaging the eyes of the user  300 , while a video reflected by the optical device  112  such as a wavelength control member is captured, the eyes of the user  300  may be directly captured not through the optical device  112 .
 
(4) The technique relating to the visual line detection in the embodiments described above is an example, and the method of detecting a visual line using the head mounted display  100  and the visual line detecting device  200  is not limited thereto.
 
     First, while an example is illustrated in which a plurality of infrared ray emitting units emitting near-infrared light as non-visible light are disposed, the technique for emitting near-infrared light to the eyes of the user  300  is not limited thereto. For example, in pixels configuring the image display device  108  of the head mounted display  100 , pixels each having a sub pixel emitting near-infrared light may be disposed, and near-infrared light may be emitted to the eyes of the user  300  by selectively causing sub pixels emitting the near-infrared light to emit light. In addition, alternatively, a configuration may be employed in which a retina projection display is disposed in the head mounted display  100  instead of the image display device  108 , display is made by the retina projection display, and pixels emitting light in a near-infrared light color are included inside a video projected to the retinas of the user  300 , whereby the emission of near-infrared light is realized. Either in the case of the display  108  or in the case of the retina projection display, sub pixels emitting near-infrared light may be regularly changed. 
     In addition, the algorithm for visual line detection is not limited to the technique described above, but any other algorithm realizing visual line detection may be used. 
     (5) In the embodiments described above, an example has been illustrated in which the audio form of a specific person is changed based on whether or not a person at whom the user  30  gazes for a predetermined or more is present. In the process, the following process may be further added. In other words, the eyes of the user  300  are imaged using the imaging unit  124 , and the visual line detecting device  200  specifies the motion (a change of the open state) of the pupils of the user  300 . Then, the visual line detecting device  200  may include a feeling specifying unit specifying the feeling of the user  300  in accordance with the open state of the pupils. Then, the video generating unit  214  may be configured to change the voice in accordance with the feeling specified by the feeling specifying unit. More specifically, for example, in a case where the pupils of the user  300  are widely open, it is determined that the person at whom the user  300  gazes has an expression of a taste or performs choreography of a taste, and the user  300  is estimated to have interest attracted to the person. Then, in a case where a video having the same tendency as the video of the expression or the choreography to which the user  300  has interest attracted is displayed (for example, a second high-point melody for a first high-point melody of a musical piece), the audio generating unit  215  raises the volume of the voice of a specific person to increase a difference from the volume of the voices of the other persons, and accordingly, an emphasizing effect including a video attracting the interest of the user  300  can be promoted. Similarly, the video generating unit  214  can change the emphasis of the video at that time to a further emphasis (for example, surrounding shading is thickened).
 
(6) In the embodiments described above, while an example is illustrated in which the display form such as an emphasis made by the video generating unit  214  is changed simultaneously with the change in the voice form made by the audio generating unit  215 , in the change in the display form, for example, switching to a CM video for selling a product or other PV relating to an idol at whom the user gazes through the internet may be performed.
 
     &lt;&lt;Other Applications&gt;&gt; 
     An image providing system according to the present invention may be an image providing system in which a server further includes a classification unit classifying a plurality of users as a group of users whose positions of the visual lines in image data satisfy a predetermined condition, and a generation unit generates image data for each user belonging to the group classified by the classification unit. 
     In addition, the image providing system may be an image providing system in which a server further includes an extraction unit extracting users whose gazing positions in visual lines are different from a target position, and a generation unit generates image data guiding the users extracted by the extraction unit to the target position. 
     Furthermore, the image providing system may be an image providing system in which a request signal includes group information relating to the group of classified users, and a generation unit generates image data including the group information. 
     In addition, the image providing system may be an image providing system in which a request signal includes guide information guiding a visual line, and a generation unit generates image data including the guide information. 
     A server according to the present invention is a server that is connected to a plurality of head mounted display systems and is used for an image providing system and may be a server including a first communication control unit transmitting image data to the connected head mounted display systems and a generation unit generating new image data according to information relating to visual lines of users transmitted from the head mounted display systems in accordance with the image data and outputting the generated new image data to the first communication control unit. 
     An image providing method according to the present invention is an image providing method used in an image providing system in which a server and a plurality of head mounted display systems are connected and may be an image providing method including: transmitting image data to the connected head mounted display systems by using the server; displaying the image data supplied from the server by using the head mounted display systems; detecting a visual line of a user viewing the image data displayed on a display unit by using each of the head mounted display system; transmitting information relating to the detected visual line to the server by using each of the head mounted display systems; and generating new image data according to the information relating to the visual line of the user transmitted from each of the head mounted display systems and transmitting the generated new image data to the head mounted display systems by using the server. 
     An image providing program according to the present invention may be an image providing program in an image providing system in which a server and a plurality of head mounted display systems are connected that realizes: transmitting image data to the connected head mounted display systems; and generating new image data according to information relating to the visual line of the user transmitted from each of the head mounted display systems in accordance with the image data and transmitting the generated new image data to the head mounted display systems in the server. 
     A head mounted display according to the present invention may be a head mounted display system including: a display unit displaying an image; a detection unit detecting visual line data of a user viewing the image displayed on the display unit; and a generation unit generating visualization data according to the detected visual line data of one or more users. 
     In addition, the generation unit of the head mounted display system may generate visualization data including the coordinate position of a viewpoint of a user specified by the visual line data detected by the detection unit. 
     In addition, the head mounted display system may further include an analysis unit analyzing the tendency of a plurality of viewpoints of users viewing an image displayed on the display unit from the visual line data detected by the detection unit, and the generation unit may generate visualization data including a result of the analysis acquired by the analysis unit. 
     In addition, the head mounted display system may include an analysis unit analyzing a viewpoint of a user in a case where a visual line of the user is not present at a predetermined target position inside the image displayed on the display unit in the visual line data detected by the detection unit, and the generation unit may generate visualization data including a result of the analysis acquired by the analysis unit. 
     In addition, the head mounted display system may include an analysis unit analyzing the trajectory of the visual line of the user for a predetermined time until an image is displayed in a case where a visual line of the user is not present at a predetermined target position inside the image displayed on the display unit in the visual line data detected by the detection unit, and the generation unit may generate visualization data including a result of the analysis acquired by the analysis unit. 
     In addition, in the head mounted display system, image data used for displaying an image is moving image data of a video game, a timer measuring an attainment time of the game is further included, and the analysis unit may analyze the attainment time measured by the timer and the visual line of the user. 
     In addition, the analysis unit of the head mounted display system may analyze the visual line of the user for each level specified by the attainment time for the visual line data of the user. 
     In addition, in the head mounted display system, image data used for displaying an image is moving image data of a video game having a displayed image changed according to an operation signal input by the user, and the analysis unit may analyze the visual line of the user at the time of starting the game. 
     In addition, the head mounted display system may further include a timer measuring a total time in which the user plays the game, and the analysis unit may analyze the visual line of the user whose total time measured by the timer is a predetermined range time. 
     In addition, in the head mounted display system, image data used for displaying an image is moving image data of a video game having a displayed image changed according to an operation signal input by the user, an operation acquiring unit acquiring information of execution of a predetermined operation by the user in the game is further included, and the analysis unit may analyze the visual line of the user in a case where the execution of a predetermined operation is acquired by the operation acquiring unit. 
     In addition, in the head mounted display system, the predetermined operation may be an operation of purchasing a content. 
     In addition, in the head mounted display system, the image data used for displaying an image is moving image data, an attribute acquiring unit acquiring attributes of the user is further included, the analysis unit may analyze the tendency of viewpoints detected by the detection unit, and the generation unit may generate visualization data including data specified at a viewpoint analyzed by the analysis unit. 
     In addition, in the head mounted display system, image data used for displaying an image is image data purchased by the user, and the analysis unit may analyze the tendency of viewpoints acquired by the detection unit for each attribute and each price of the image data. 
     In addition, the generation unit of the head mounted display system may generate data acquired by adding the position of the viewpoint of the user acquired by the detection unit to the image as visualization data. 
     In addition, in the head mounted display system, image data used for displaying an image is moving image data, and the visualization data may include a time axis display section specifying a relation between the viewpoint of each user in the image data and the time axis of the image data. 
     In addition, the generation unit of the head mounted display system may generate data acquired by adding a bar graph including a result of the analysis acquired by the analysis unit as the visualization data. 
     In addition, the head mounted display system may further include an output unit outputting the generated visualization data. 
     A data displaying method according to the present invention may be a data displaying method including: displaying an image on a display unit; detecting visual line data of users viewing the image displayed on the display unit; and generating visualization data according to the detected visual line data of one or more users. 
     A data generating program according to the present invention may be a data generating program realizing a display function displaying an image on a display unit, a detection function detecting visual line data of users viewing the image displayed on the display unit, and a generation function generating visualization data according to the detected visual line data of one or more users in a head mounted display system. 
     A video display system according to the present invention may be a video display system including: a video output unit outputting a video including one or more persons; an audio output unit outputting an audio including a sound corresponding to one or more persons; a lighting unit emitting illumination light including non-visible light toward the anterior ocular segment of the user; an imaging unit capturing an anterior ocular segment image including the anterior ocular segment of the user; a visual line detecting unit detecting the visual line direction of the user by analyzing the anterior ocular segment image; and an audio generating unit specifying a person in a case where one or more persons are present in a video output by the video output unit in the visual line direction of the user detected by the visual line detecting unit and generating audio data such that an output state of a voice output from the audio output unit in correspondence with the specified person is different from an output state of the other voices so as to be identifiable for the user. 
     In addition, the audio generating unit of the video display system may generate the audio data such that the volume of the sound of the specified person is higher than that of the other voices so as to be identifiable for the user. 
     In addition, the audio generating unit of the video display system may give an additional function in addition to the setting of the volume of the sound of the specified person to be higher than that of the other voices. 
     In addition, the video display system may include a video generating unit specifying a person in a case where one or more persons are present in the video output by the video output unit in the visual line direction of the user detected by the visual line detecting unit and changing the display form such that the user can gaze at a video of a predetermined area including at least a part of the specified person more easily than the video of an area other than the predetermined area. 
     In addition, the video output unit of the video display system may be disposed in a head mounted display worn by the user on the head. 
     In addition, a video displaying method according to the present invention may be a video displaying method including: outputting a video including one or more persons; outputting an audio including a sound corresponding to one or more persons; emitting illumination light including non-visible light toward the anterior ocular segment of the user; capturing an anterior ocular segment image including the anterior ocular segment of the user; detecting the visual line direction of the user by analyzing the anterior ocular segment image; and specifying a person in a case where one or more persons are present in a video output in the visual line direction of the user detected in the detection of the visual line and generating audio data such that an output state of a voice output in correspondence with the specified person is different from an output state of the other voices so as to be identifiable for the user. 
     A video displaying program according to the present invention may be a video displaying program realizing: a video output function outputting a video including one or more persons; an audio output function outputting an audio including a sound corresponding to one or more persons; a lighting function emitting illumination light including non-visible light toward the anterior ocular segment of the user; an imaging function capturing an anterior ocular segment image including the anterior ocular segment of the user; a visual line detecting function detecting the visual line direction of the user by analyzing the anterior ocular segment image; and an audio generating function specifying a person in a case where one or more persons are present in an output video in the visual line direction of the user detected by the detection function and generating audio data such that an output state of a voice output in correspondence with the specified person is different from an output state of the other voices so as to be identifiable for the user. 
     The present invention can be used for a head mounted display.