Patent Publication Number: US-10334169-B2

Title: Display system

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a display system. 
     2. Related Art 
     As a technique of a display system, there is known a technique for photographing and displaying an image (e.g., JP-A-2012-160898 (Patent Literature 1) and JP-A-2012-023768 (Patent Literature 2)). 
     Patent Literature 1 discloses a remote support system including a head mounted display mounted on the head of an operator and a display device. The remote support system causes a remote monitor device to display an image of a target object picked up by a camera included in the head mounted display. In the technique of Patent Literature 1, in order to suppress a tilt of the target object displayed on the display device even when the operator tilts the neck, tilt correction is performed on picked-up image data. 
     In the technique of Patent Literature 2, when it is determined that an image pickup device is moving at acceleration exceeding a threshold, a frame rate of an image pickup section of the image pickup device is reduced. 
     When a photographer causes a display device located in a place different from an image pickup section to display a moving image, because of an unintended movement of the photographer, a moving image is sometimes displayed on the display device as if shaking. In this case, as illustrated below, various deficiencies could occur because the moving image is displayed as if shaking. For example, there is a deficiency in that a person viewing the moving image displayed on the display device has visually induced motion sickness. For example, there is a deficiency in that the target object in the moving image displayed on the display device cannot be accurately grasped. 
     On the other hand, it is conceivable to detect a shake of the image pickup section, correct moving image data to cancel the detected shake, and cause the display device to display the moving image data to reduce the occurrence of the deficiencies. However, when the moving image data is corrected to cancel the detected shake, a moving image is corrected even when the photographer intentionally moves the image pickup section. Therefore, a moving image different from a moving image that the photographer actually desires to acquire is displayed on the display device. 
     Besides, in the display system, there are demands for a reduction in size, a reduction in costs, power saving, facilitation of manufacturing, improvement of convenience of use, and the like. 
     SUMMARY 
     An advantage of some aspects of the invention is to solve at least apart of the problems described above, and the invention can be implemented as the following aspects. 
     (1) According to an aspect of the invention, a display system is provided. The display system includes: an image pickup section configured to pick up an image; a sensor for detecting a movement of the image pickup section; a data processing section configured to cut out a predetermined cutout region of the image and generate image data for display; and a data transmitting section configured to transmit the image data for display to a display device. When the movement of the image pickup section detected by the sensor satisfies a predetermined condition, the data processing section sets, in a reference cutout position set in advance, a specified position of the cutout region for cutting out the image and generates the image data for display. When the movement does not satisfy the predetermined condition, the data processing section shifts the specified position from the reference cutout position in a direction opposite to the movement of the image pickup section from a reference position and generates the image data for display. According to this aspect, it is possible to, while causing the display device to display a moving image including a target object, reduce a shake of an image displayed on the display device due to the movement of the image pickup section that does not satisfy the predetermined condition. Note that, in this specification, a form of the data processing section cutting out an image includes a form of reading out data used as the image data for display from image data. 
     (2) In the display system according to the aspect, the predetermined condition may be a condition that a moving amount of the image pickup section from the reference position is continuously equal to or larger than a predetermined threshold for a predetermined time or more. According to this aspect, a movement of the image pickup section equal to or larger than the predetermined threshold, which occurs in a time period shorter than the predetermined time, is not reflected on the image displayed on the display device. Therefore, it is possible to further reduce the shake of the image displayed on the display device. 
     (3) In the display system according to the aspect, the data processing section may include an interpolation processing section configured to generate, when a second image represented by a second version of the image data for display generated when the predetermined condition is satisfied is displayed on the display device after a first image represented by a first version of the image data for display generated when the predetermined condition is not satisfied, image data for interpolation display for interpolating a difference between the first image and the second image, and the interpolation processing section may insert the image data for interpolation display between the first and second versions of image data for display arranged in time series. According to this aspect, an interpolation image is inserted between the first image and the second image arranged in time series and is displayed on the display device. Therefore, it is possible to suppress content of the image displayed on the display device from being suddenly switched. 
     (4) In the display system according to the aspect, the data processing section may be capable of curtailing a plurality of images picked up by the image pickup section and generated at a first frame rate and causing the data transmitting section to transmit the image data for display at a second frame rate lower than the first frame rate, and the interpolation processing section may select image data for interpolation serving as the image data located between the image data serving as a base of the first version of image data for display and the image data serving as a base of the second version of image data for display and scheduled to be curtailed at the second frame rate, cut out an image represented by the image data for interpolation in the cutout region centering on the reference cutout position, and generate the image data for interpolation display. According to this aspect, it is possible to generate the image data for interpolation display effectively using an image scheduled to be curtailed at the second frame rate. 
     (5) The display system according to the aspect, the interpolation processing section may set, with respect to the image data serving as a base of at least a singularity of the image data for display located, in time series, between a first version of the image data serving as a base of the first version of image data for display and a second version of the image data serving as a base of the second version of image data for display, the specified position to interpolate the movement of the image pickup section from the generation of the first version of image data to the generation of the second version of image data and generate the image data for interpolation display. According to this aspect, it is possible to generate the image data for interpolation display using the image data serving as a base of the image data for display. 
     (6) In the display system according to the aspect, the data processing section may further include a cutout-position setting section configured to set the reference cutout position on the basis of a region of attention that should be paid attention. According to this aspect, it is possible to easily set the reference cutout position on the basis of the region of attention. 
     (7) In the display system according to the aspect, the cutout-position setting section may set the reference cutout position using, as the region of attention, overlapping image regions among a plurality of the images picked up by the image pickup section in a predetermined period. According to this aspect, it is possible to easily set the region of attention on the basis of the overlapping image regions. 
     (8) In the display system according to the aspect, the cutout-position setting section may set the reference cutout position using, as the region of attention, a region including a designated target object designated from the outside. According to this aspect, it is possible to set, as the region of attention, the region including the designated target object designated from the outside. 
     (9) In the display system according to the aspect, the display system may further include an image display section configured to cause a user of the image pickup section to visually recognize the designated target object. According to this aspect, the user can visually recognize the designated target object on the image display section. 
     (10) In the display system according to the aspect, the display system may further include a storing section configured to store characteristic information for detecting a target object of attention, and, when the target object of attention is detected in the image represented by the image data using the characteristic information, the cutout-position setting section may determine, as the region of attention, a region including the target object of attention and set the reference cutout position. According to this aspect, it is possible to set the reference cutout position by automatically detecting the target object of attention with the cutout-position setting section. 
     (11) In the display system according to the aspect, the cutout-position setting section may set a specified position of the region of attention as the reference cutout position. According to this aspect, it is possible to surely locate the target object of attention within a cutout region centering on the reference cutout position. 
     (12) In the display system according to the aspect, the display system may further include a distance detecting section configured to detect a distance between the image pickup section and a predetermined target object included in the image, and the data processing section may further include a cutout-region setting section configured to change a size of the cutout region according to the distance detected by the distance detecting section. According to the aspect, it is possible to change the size of the cutout region according to the distance detected by the distance detecting section. 
     (13) In the display system according to the aspect, the data processing section may set the cutout region larger as the distance is larger. According to this aspect, it is possible to suppress the size of the target object displayed on a display section from greatly fluctuating. 
     (14) In the display system according to the aspect, the distance detecting section may detect the distance by comparing an actual size of the predetermined target object and a size of the predetermined target object in the image. According to this aspect, it is possible to compare the size of the predetermined target object and the size of the predetermined target object in the image and detect the distance. 
     (15) In the display system according to the aspect, the same identification information may be given to each of image data representing the image and detection information of the sensor at the time when the image data is generated. According to this aspect, it is possible to easily associate the image data and the detection information. 
     (16) In the display system according to the aspect, the display system may further include an information processing device configured to acquire the image photographed by the image pickup section, and the data processing section may be provided in the information processing device. With the display system according to this aspect, it is possible to implement the functions of the data processing section in a server. 
     (17) In the display system according to the aspect, the display system may further include an image display device including a display section configured to display a virtual image and capable of transmitting an outside world, and the data processing section may be provided in the image display device. According to this aspect, it is possible to implement the functions of the data processing section in the image display device. 
     (18) In the display system according to the aspect, the display system may further include a display device configured to display an image for display represented by the image data for display, and the data processing section may be provided in the display device. According to this aspect, it is possible to implement the functions of the data processing section in the display device. 
     Not all of the plurality of components included in the aspects of the invention explained above are essential. In order to solve apart or all of the problems explained above or achieve a part of all of the effects described in this specification, concerning apart of the plurality of components, it is possible to appropriately perform a change, deletion, replacement of the components with new components, and deletion of a part of limitation contents. In order to solve a part or all of the problems explained above or in order to achieve a part or all of the effects described in this specification, it is also possible to combine a part or all of the technical features included in one aspect of the invention explained above with a part or all of the technical features included in the other aspects of the invention to form an independent one aspect of the invention. 
     For example, one aspect of the invention can be implemented as an apparatus including a part or all of the four components, that is, the image pickup section, the sensor, the data processing section, and the data transmitting section. That is, the apparatus may include or may not include the image pickup section. The apparatus may or may not include the sensor. The apparatus may or may not include the data processing section. The apparatus may or may not include the data transmitting section. Such an apparatus can be implemented as, for example, a display system but can also be implemented as systems other than the display system. A part or all of the technical features of the aspects of the display system explained above can be applied to the apparatus. 
     The invention can be implemented in various forms. For example, the invention can be implemented in forms such as a display system, a method of controlling the display system, an image display system including a head-mounted display device, a computer program for implementing functions of the display system, and a storage medium having stored therein the computer program. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is an explanatory diagram showing the schematic configuration of a display system in a first embodiment. 
         FIG. 2  is an exterior perspective view of a printer serving as a work target object. 
         FIG. 3  is a block diagram functionally showing the configuration of an HMD in the first embodiment. 
         FIG. 4  is an explanatory diagram showing an example of augmented reality display by the HMD. 
         FIG. 5  is a block diagram functionally showing the configuration of a server. 
         FIGS. 6A and 6B  are diagrams for explaining a relation between a cutout region and an image pickup region. 
         FIG. 7  is a flowchart of a processing flow of image data executed by a CPU. 
         FIG. 8  is a diagram for explaining a reference cutout region set by a cutout-position setting section. 
         FIG. 9  is a diagram for explaining a processing flow. 
         FIG. 10  is a diagram showing a change of a movement in a horizontal plane of a camera. 
         FIG. 11  is a diagram showing a relation between the image pickup region and the reference cutout region at reference time. 
         FIG. 12  is a diagram showing a relation between the image pickup region and the cutout region at time t 1 . 
         FIG. 13  is a diagram showing a relation between the image pickup region and the cutout region at time t 8 . 
         FIG. 14  is a block diagram functionally showing the configuration of an HMD in a second embodiment. 
         FIG. 15  is a block diagram functionally showing the configuration of a server in the second embodiment. 
         FIGS. 16A to 16C  are diagrams for explaining an interpolation processing method executed by an interpolation processing section. 
         FIGS. 17A and 175  are diagrams for explaining another interpolation processing method executed by the interpolation processing section. 
         FIGS. 18A and 18B  are diagrams for explaining processing contents of a cutout-region setting section. 
         FIG. 19  is a diagram for explaining first another setting method for a reference cutout position. 
         FIG. 20  is a diagram for explaining second another setting method for the reference cutout position. 
         FIGS. 21A and 21B  are diagrams for explaining third another setting method for the reference cutout position. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A. First Embodiment 
     A-1. Configuration of a Display System 
       FIG. 1  is an explanatory diagram showing the schematic configuration of a display system in a first embodiment of the invention.  FIG. 2  is an exterior perspective view of a printer  70  serving as a work target object. 
     A display system  1  ( FIG. 1 ) includes a head-mounted display device  100  functioning as an image display device, a server  60  functioning as a data processing device (an information processing device), and a personal computer (PC)  250  functioning as a display device. The PC  250  includes a display section  251  for displaying an image. The display section  251  displays a moving image transmitted from the head-mounted display device  100  through the server  60 . 
     The head-mounted display device  100  is connected to the Internet INT by radio communication via a communication carrier BS. The PC  200  is connected to the Internet INT by radio communication via the communication carrier BS. The server  60  is connected to the Internet INT by wired communication. As a result, the server  60 , the head-mounted display device  100 , and the PC  250  can perform data communication one another via the Internet INT. The communication carrier BS includes a transmission/reception antenna, a radio base station, and a switching station. 
     The display system  1  can be used as, for example, a remote support system. For example, the remote support system causes the remote display section  251  to display a moving image acquired by the head-mounted display device  100  worn by a user. An instructor operating the PC  250  instructs the user about work contents on the basis of the moving image. In this embodiment, the operation of the display system  1  at the time when the user performs initial setting and maintenance/inspection of the printer  70  functioning as the work target object shown in  FIG. 2  is explained. That is, the remote support system acquires, with the head-mounted display device  100 , a moving image including the printer  70  and causes the display section  251  to display the acquired moving image. The instructor operating the PC  100  instructs the user about work contents for the printer  70 . 
     The printer  70  ( FIG. 2 ) is an inkjet printer that conveys not-shown roll paper, ejects an ink on the roll paper, and forms an image. The printer  70  includes a paper feeding slot  71  in which the roll paper is disposed, a spindle bearing  75  in which a spindle of the roll paper is set, an open-closable cover  72  that covers the roll paper, a discharge section  76  from which the roll paper, on which the image is formed, is discharged, a box-type holding section  77  that holds the discharged roll paper, and an operation panel  78  for displaying a state (e.g., an ink end state and a power supply state) of the printer  70  and setting the operation of the printer  70 . 
     The operation panel  78  includes various buttons B 1  to B 6  for controlling the operation (e.g., power ON/OFF) of the printer  70 , various lamps D 1  to D 4  for displaying the state of the printer  70 , and a display  79  that displays, for example, the state of the printer  70 . 
     The head-mounted display device  100  ( FIG. 1 ) is a display device mounted on a head and is called head mounted display (HMD) as well. The HMD  100  in this embodiment is a head mounted display of an optical transmission type with which the user can visually recognize a virtual image and, at the same time, directly visually recognize an outside scene. 
     The server  60  receives moving image data DM 1  and detection information DT 1  of a nine-axis sensor  66  included in the HMD  100  from the HMD  100 . The server  60  receives the moving image data DM 1  at a first frame rate FR 1 . The server  60  applies, on the basis of the received moving image data DM 1  and the received detection information DT 1 , predetermined data processing to frame image data FM 1  configuring the moving image data DM 1  and generates frame image data for display FM 2 . The server  60  sequentially transmits the generated frame image data for display FM 2  to the PC  250 . The server  60  is capable of transmitting the frame image data for display FM 2  to the PC  250  at a second frame rate FR 2 . The second frame rate FR 2  is lower than the first frame rate FR 1 . For example, the first frame rate FR 1  is 30 fps and the second frame rate FR 2  is 5 fps. Note that, since the frame image data forms an image displayed by the display section  251 , the frame image data can be referred to as frame image as well. 
     The PC  250 , which has received the frame image data for display FM 2 , causes the display section  251  to display the frame image data for display FM 2  at the second frame rate FR 2 . Consequently, the display section  251  displays a moving image represented by moving image data DM 2 . When the display system  1  is used as the remote support system, the instructor views the moving image displayed on the display section  251  and instructs the user wearing the HMD  100  about work contents and the like. Note that details of data processing of the frame image data FM 1  executed by the server  60  are explained below. 
     A-2. Configuration of the Head-Mounted Display Device (HMD) 
       FIG. 3  is a Block Diagram Functionally Showing the configuration of the HMD  100 . The configuration of the HMD  100  is explained with reference to  FIGS. 1 and 3 . As shown in  FIG. 1 , the HMD  100  includes a headphone section  90 , an image display section  20 , a microphone section  30 , and a control section  10 . 
     The headphone section  90  is wearable on the head of the user. The headphone section  90  includes a headband  91  bent to be wearable along the head and right and left ear cups  92  and  93  provided at both ends of the headband  91 . An acoustic speaker  94  ( FIG. 3 ) for a right channel is provided on the inside of the ear cup  92  on the right side. An acoustic speaker  95  ( FIG. 3 ) for a left channel is provided on the inside of the ear cup  93  on the left side. The image display section  20  is attached to the headband  91  in a fixed form. 
     The image display section  20  is capable of causing the user to visually recognize a virtual image in a state in which the image display section  20  is worn on the head of the user. The image display section  20  has an eyeglass shape. The image display section  20  includes a right holding section  21 , a right display driving section  22 , a left holding section  23 , a left display driving section  24 , a right optical-image display section  26 , and a left optical-image display section  28 . The right optical-image display section  26  and the left optical-image display section  28  are respectively located in front of the right eye and in front of the left eye of the user when the user wears the headband  91 . One end of the right optical-image display section  26  and one end of the left optical-image display section  28  are connected to each other in a position corresponding to the middle of the forehead of the user at the time when the user wears the image display section  20 . 
     The right holding section  21  extends from an end portion ER, which is the other end of the right optical-image display section  26 , in substantially the horizontal direction and is fixed to the vicinity of the end portion on the right side of the headband  91 . Similarly, the left holding section  23  extends from an end portion EL, which is the other end of the left optical-image display section  28 , in substantially the horizontal direction and is fixed to the vicinity of the end portion on the left side of the headband  91 . The right holding section  21  and the left holding section  23  hold the optical-image display sections  26  and  28  such that the optical-image display sections  26  and  28  are located in front of the eyes of the user wearing the headband  91  on the head. 
     The right display driving section  22  is disposed on the inner side of the right holding section  21 , in other words, on a side opposed to the head of the user at the time when the user wears the image display section  20 . The left display driving section  24  is disposed on the inner side of the left holding section  23 . Note that, in the following explanation, the right holding section  21  and the left holding section  23  are explained as “holding sections” without being distinguished. Similarly, the right display driving section  22  and the left display driving section  24  are explained as “display driving sections” without being distinguished. The right optical-image display section  26  and the left optical-image display section  28  are explained as “optical-image display sections” without being distinguished. 
     The display driving sections include liquid crystal displays (hereinafter referred to as “LCDs”)  241  and  242  and projection optical systems  251  and  252  ( FIG. 3 ). Details of the configuration of the display driving sections are explained below. The optical-image display sections functioning as optical members include light guide plates  261  and  262  ( FIG. 3 ) and dimming plates. The light guide plates  261  and  262  are formed of a light transmissive resin material or the like and guide image lights output from the display driving sections to the eyes of the user. The dimming plates are thin plate-like optical elements and are disposed to cover the front side (a side opposite to the side of the eyes of the user) of the image display section  20 . The dimming plates protect the light guide plates  261  and  262  and suppress damage, adhesion of stain, and the like to the light guide plates  261  and  262 . By adjusting the light transmittance of the dimming plates, it is possible to adjust an external light amount entering the eyes of the user and adjust easiness of visual recognition of a virtual image. Note that the dimming plates can be omitted. 
     The microphone section  30  ( FIG. 1 ) includes a microphone  31 , an arm  32 , and a coupling section  33 . The microphone  31  is a sound input section that converts sound into an electric signal and is connected to the distal end of the arm  32 . An end portion of the arm  32  on the opposite side of the microphone  31  is coupled to an upper surface  92   a  of the right ear cup  92  of the image display section  20  by the coupling section  33 . According to the coupling, the microphone  31  is located in front of the mouth of the user. Note that the coupling section  33  couples the arm  32  to be capable of turning and to be capable of being fixed in any position. 
     An integrated object of the image display section  20 , the microphone section  30 , and the headphone section  90  and the control section  10  are connected by a connection cord  40 . One end of the connection cord  40  is inserted into the right ear cup  92  of the headphone section  90 , divided according to necessity, and connected to the left and right display driving sections  22  and  24  of the image display section  20 , the left and right speakers  94  and  95 , and the microphone  31  of the microphone section  30 . The other end of the connection cord  40  is connected to the control section  10 . Connectors (not shown in the figure) fitting with each other are respectively provided at the end portion on the opposite side of the right ear cup  92  in the connection cord  40  and the control section  10 . The integrated object and the control section  10  are connected and disconnected according to fitting and unfitting of the connector of the connection cord  40  and the connector of the control section  10 . As the connection cord  40 , for example, a metal cable and an optical fiber can be adopted. 
     The control section  10  ( FIG. 1 ) is a device for controlling the HMD  100 . The control section  10  includes a lighting section  12 , a touch pad  14 , a cross key  16 , and a power switch  18 . The lighting section  12  notifies, with a light emission form thereof, an operation state (e.g., power ON/OFF) of the HMD  100 . As the lighting section  12 , for example, an LED (Light Emitting Diode) can be used. The touch pad  14  detects touch operation on an operation surface of the touch pad  14  and outputs a signal corresponding to detection content. As the touch pad  14 , various touch pads of an electrostatic type, a pressure detection type, and an optical type can be adopted. The cross key  16  detects pressing operation on center portions of keys corresponding to the upward, downward, left, and right directions and a cross key and outputs a signal corresponding to detection content. The power switch  18  detects slide operation of a switch to switch a state of a power supply of the HMD  100 . 
     The control section  10  ( FIG. 3 ) includes an input-information acquiring section  110 , a storing section  120 , a power supply  130 , a radio communication section  132 , a GPS module  134 , a CPU  140 , an interface  180 , transmitting sections (Txs)  51  and  52 , and a timer  135 . The sections are connected to one another by a not-shown bus. 
     The input-information acquiring section  110  acquires, for example, signals corresponding to operation inputs to the touch pad  14 , the cross key  16 , the power switch  18 , and the like. The storing section  120  is configured by a ROM, a RAM, a DRAM, a hard disk, or the like. 
     The power supply  130  supplies electric power to the sections of the HMD  100 . As the power supply  130 , for example, a secondary battery such as a lithium polymer battery or a lithium ion battery can be used. Further, instead of the secondary battery, a primary battery or a fuel battery may be used. Alternatively, the sections may receive wireless power supply and operate. The sections may receive power supply from a solar cell and a capacitor. The radio communication section  132  performs radio communication with other apparatuses according to a predetermined radio communication standard such as a wireless LAN, Bluetooth (registered trademark), or iBeacon (registered trademark). The GPS module  134  receives a signal from a GPS satellite to thereby detect the present position of the GPS module  134 . 
     The CPU  140  reads out and executes computer programs stored in the storing section  120  to thereby function as an operating system (OS)  150 , an image processing section  160 , a display control section  162 , and a sound processing section  170 . 
     The image processing section  160  generates a signal on the basis of contents (videos) input via the interface  180  and the radio communication section  132 . The image processing section  160  supplies the generated signal to the image display section  20  via the connection cord  40  to control the image display section  20 . The signal to be supplied to the image display section  20  is different in an analog format and a digital format. In the case of the analog format, the image processing section  160  generates and transmits a clock signal PCLK, a vertical synchronization signal VSync, a horizontal synchronization signal HSync, and image data Data. Specifically, the image processing section  160  acquires an image signal included in contents. For example, in the case of a moving image, in general, the acquired image signal is an analog signal configured from thirty frame images per one second. The image processing section  160  separates synchronization signals such as the vertical synchronization signal VSync and the horizontal synchronization signal HSync from the acquired image signal and generates the clock signal PCLK with a PLL circuit or the like according to cycles of the synchronization signals. The image processing section  160  converts the analog image signal, from which the synchronization signals are separated, into a digital image signal using an A/D conversion circuit or the like. The image processing section  160  stores the digital image signal after the conversion in the DRAM in the storing section  120  frame by frame as the image data Data of RGB data. 
     On the other hand, in the case of the digital format, the image processing section  160  generates and transmits the clock signal PCLK and the image data Data. Specifically, when the contents are the digital format, the clock signal PCLK is output in synchronization with the image signal. Therefore, the generation of the vertical synchronization signal VSync and the horizontal synchronization signal HSync and the A/D conversion of the analog image signal are unnecessary. Note that the image processing section  160  may execute, on the image data Data stored in the storing section  120 , image processing such as resolution conversion processing, various kinds of tone correction processing such as adjustment of luminance and chroma, and keystone correction processing. 
     The image processing section  160  transmits the generated clock signal PCLK, the generated vertical synchronization signal VSync, and the generated horizontal synchronization signal HSync and the image data Data stored in the DRAM in the storing section  120  respectively via the transmitting sections  51  and  52 . Note that the image data Data transmitted via the transmitting section  51  is referred to as “image data for right eye Data 1 ” as well. The image data Data transmitted via the transmitting section  52  is referred to as “image data for left eye Data 2 ” as well. The transmitting sections  51  and  52  function as a transceiver for serial transmission between the control section  10  and the image display section  20 . 
     The display control section  162  generates control signals for controlling the right display driving section  22  and the left display driving section  24 . Specifically, the display control section  162  individually controls, with the control signals, driving ON/OFF of a right LCD  241  by a right LCD control section  211 , driving ON/OFF of a right backlight  221  by a right backlight control section  201 , driving ON/OFF of a left LCD  242  by a left LCD control section  212 , and driving ON/OFF of a left backlight  222  by a left backlight control section  202 , and the like to thereby control generation and emission of image lights respectively by the right display driving section  22  and the left display driving section  24 . The display control section  162  transmits the control signals for the right LCD control section  211  and the left LCD control section  212  respectively via the transmitting sections  51  and  52 . Similarly, the display control section  162  transmits the control signals respectively to the right backlight control section  201  and the left backlight control section  202 . 
     The sound processing section  170  acquires a sound signal from the outside (e.g., contents), amplifies the acquired sound signal, and supplies the sound signal to the speaker  94  in the right ear cup  92  and the speaker  95  in the left ear cup  93  connected to a coupling member  46 . Note that, for example, when a Dolby (registered trademark) system is adopted, processing for the sound signal is performed. Different kinds of sound with varied frequencies or the like are respectively output from the right and left speakers  94  and  95 . 
     The interface  180  is an interface for connecting various external apparatuses OA, which are supply sources of contents, to the control section  10 . Examples of the external apparatuses OA include a personal computer  291 , a cellular phone terminal  292 , and a game terminal  293 . As the interface  180 , for example, a USB interface, a micro USB interface, and an interface for a memory card can be used. 
     The image display section  20  includes the right display driving section  22 , the left display driving section  24 , a right light guide plate  261  functioning as the right optical-image display section  26 , a left light guide plate  262  functioning as the left optical-image display section  28 , a camera  61  (see  FIG. 1  as well) functioning as an image pickup section, and the nine-axis sensor  66 . The timer  135  has a function of detecting the present time. 
     The camera  61  is an RGB camera and is disposed in a position corresponding to the root of the nose of the user at the time when the user wears the image display section  20 . Therefore, the camera  61  picks up a color image of an outside world in a predetermined direction of the HMD  100 , that is, a direction that the user faces in a state in which the user wears the image display section  20  on the head. Note that the camera  61  can be a monochrome camera instead of the RGB camera. The camera  61  picks up a moving image. The picked-up moving image is stored in the storing section  120  as the moving image data DM 1  configured from a plurality of frame image data FM 1 . Time data at a point in time when the frame image data FM 1  is stored in the storing section  120  is given to the frame image data FM 1  by the timer  135 . The point in time when the frame image data FM 1  is stored in the storing section  120  can also be considered a point in time when the frame image data FM 1  is generated. 
     The nine-axis sensor  66  functioning as a sensor is a motion sensor that detects acceleration (three axes of an X axis, a Y axis, and a Z axis), angular velocity (three axes), and terrestrial magnetism (three axes). In this embodiment, the nine-axis sensor  66  is disposed in a position corresponding to the middle of the forehead of the user. The nine-axis sensor  66  is provided in the image display section  20 . Therefore, when the image display section  20  is worn on the head of the user, the nine-axis sensor  66  can detect a movement of the head of the user (specifically, the camera  61 ) on the basis of the detection information DT 1  of the nine-axis sensor  66 . The direction of the image display section  20 , that is, a visual field of the user can be specified from the detected movement of the head. Sensor detection information of the nine-axis sensor  66  is stored in the storing section  120 . Time data at a point in time when the detection information DT 1  is stored in the storing section  120  is given to the detection information DT 1  by the timer  135 . As explained above, the time data serving as the same identification information are given to the frame image data FM 1  and the detection information DT 1 . The frame image data FM 1  and the detection information DT 1  can be easily associated by the time data. Note that the identification information is not limited to the time data. For example, the identification information may be data (e.g., number data) representing the same content. 
     The right display driving section  22  includes a receiving section (Rx)  53 , the right backlight (BL) control section  201  and the right backlight (BL)  221  functioning as a light source, the right LCD control section  211  and the right LCD  241  functioning as a display element, and a right projection optical system  251 . Note that the right backlight control section  201 , the right LCD control section  211 , the right backlight  221 , and the right LCD  241  are collectively referred to as “image-light generating section” as well. 
     The receiving section  53  functions as a receiver for serial transmission between the control section  10  and the image display section  20 . The right backlight control section  201  drives the right backlight  221  on the basis of an input control signal. The right backlight  221  is, for example, a light emitting body such as an LED or an electroluminescence (EL) element. The right LCD control section  211  drives the right LCD  241  on the basis of the clock signal PCLK, the vertical synchronization signal VSync, the horizontal synchronization signal HSync, and the image data for right eye Data 1  input via the receiving section  53 . The right LCD  241  is a transmissive liquid crystal panel on which a plurality of pixels are arranged in a matrix shape. The right LCD  241  changes, by driving liquid crystal in pixel positions arranged in the matrix shape, the transmittance of light transmitted through the right LCD  241  to thereby modulate illumination light radiated from the right backlight  221  into effective image light representing an image. 
     The right projection optical system  251  is configured by a collimate lens that changes the image light emitted from the right LCD  241  to light beams in a parallel state. The right light guide plate  261  functioning as the right optical-image display section  26  guides the image light output from the right projection optical system  251  to the right eye RE of the user while reflecting the image light along a predetermined optical path. For the optical-image display section, any system can be used as long as the optical-image display section forms a virtual image in front of the eyes of the user using the image light. For example, a diffraction grating may be used or a semitransparent reflection film may be used. Note that the HMD  100  emitting the image light is also referred to as “display an image” in this specification. 
     The left display driving section  24  includes a configuration same as the configuration of the right display driving section  22 . That is, the left display driving section  24  includes a receiving section (Rx)  54 , the left backlight (BL) control section  202  and the left backlight (BL)  222  functioning as a light source, the left LCD control section  212  and the left LCD  242  functioning as a display element, and a left projection optical system  252 . Like the right LCD  241 , the left LCD  242  changes, by driving liquid crystal in pixel positions arranged in the matrix shape, the transmittance of light transmitted through the left LCD  242  to thereby modulate illumination light radiated from the left backlight  222  into effective image light representing an image. Note that, although a backlight system is adopted in this embodiment, the image light may be emitted using a front light system or a reflection system. 
       FIG. 4  is an explanatory diagram showing an example of augmented reality display by the HMD  100 . In  FIG. 4 , a visual field VR of the user is illustrated. The image lights guided to both the eyes of the user of the HMD  100  are focused on the retinas of the user, whereby the user visually recognizes a image VI serving as augmented reality (AR). The optical-image display sections  26  and  28  transmit light from an outside world SC, whereby the user visually recognizes the outside world SC. In this way, the user of the HMD  100  in this embodiment can view the image VI and the outside scene SC behind the image VI in a portion where the image VI is displayed in the visual field VR. The user can view only the outside world SC in a portion where the image VI is not displayed in the visual field VR. 
     In the example shown in  FIG. 4 , images VIa and VIb are waiting screens for the user to perform predetermined work. In the image VIb on the lower right, a data processing start mark SM serving as a trigger for data processing of the frame image data FM 1  executed by the server  60  is displayed. In the image VIa on the upper left, an image picked up by the camera  61  is displayed. The user sets the direction of the camera  61  by adjusting, with reference to the image via picked up by the camera  61 , the position of the head such that a target object of attention (e.g., the operation panel  78 ) is in a center RCe of an image pickup region CPR. The user selects the data processing start mark SM. Consequently, the frame image data FM 1  in which the target object of attention is arranged in the center RCe of the image pickup region CPR, that is, the frame image data FM 1  given with processing start data SD is generated and stored in the storing section  120 . 
     A-3. Configuration of the Server 
       FIG. 5  is a block diagram functionally showing the configuration of the server  60 . The server  60  includes a CPU  640 , a ROM  670 , a RAM  672 , a communication interface (I/F)  632 , and a storing section  620 . The sections are connected to one another by a not-shown bus. 
     The CPU  640  develops, in the RAM  672 , computer programs stored in the ROM  320  or the storing section  620  and executes the computer programs to thereby control the sections of the server  60 . Besides, the CPU  640  also functions as a data acquiring section  642  that acquires data from the outside through the communication interface (I/F)  632  and a data transmitting section  648  that transmits data to the outside through the communication i/F  632 . 
     A communication interface  340  includes a radio communication interface and a wired communication interface. The radio communication interface includes a not-shown transmission/reception circuit and performs demodulation of a radio wave received via an antenna and generation of data and generation and modulation of a radio wave transmitted via the antenna. The wired communication interface is connected to other devices via a wired cable. 
     A storing section  350  is configured by a DRAM, a hard disk, and the like. The storing section  350  stores a condition table  621  used by a condition determining section  644 . The storing section  350  stores the moving image data DM 1  picked up by the camera  61 . 
     The CPU  640  transfers a computer program stored in the ROM  670  to the RAM  672  and executes the computer program to thereby function as a data processing section  646 . The data processing section  646  includes a cutout-position setting section  641 , a cutting out section  643 , and a condition determining section  644 . The data processing section  646  extracts a part of the plurality of frame image data FM 1  stored in the storing section  620  and performs data processing on the extracted frame image data FM 1  to generate the frame image data for display FM 2 . The data processing section  646  is capable of transmitting the frame image data for display FM 2  to the PC  250  at the second frame rate FR 2  via the data transmitting section  648 . 
     The cutting out section  643  cuts out, with respect to the frame image data FM 1  configuring the moving image data DM 1 , a predetermined cutout region from a frame image represented by the frame image data FM 1  and generates the frame image data for display FM 2  to be displayed by the display section  251 . 
       FIGS. 6A and 6B  are diagrams for explaining a relation between a cutout region EPR and an image pickup region CPR of the camera  61  represented by the frame image data FM 1 . When an image of the image pickup region CPR including the operation panel  78  is picked up by the camera  61 , the cutting out section  643  cuts out the cutout region EPR smaller than the image pickup region CPR from a frame image and generates the frame image data for display FM 2 . The PC  250  causes the display section  251  to display the frame image data for display FM 2  such that the sizes of the cutout region EPR and the display region of the display section  251  coincide with each other. In a normal mode of the server  60  before receiving the processing start data SD, a center position Ce serving as a specified position of the cutout region EPR is set in the center RCe of the image pickup region CPR. When receiving the processing start data SD, the server  60  shifts to a processing mode. In the processing mode, the position of the center position Ce is determined according to whether a predetermined condition is satisfied. Note that the specified position is not limited to the center position Ce as long as the specified position specifies the position of the cutout region EPR. For example, a coordinate position of at least one of four corners of the cutout region EPR may be set as the specified position. 
     In this embodiment, the size of the cutout region EPR is a fixed value set in advance. Note that the size of the cutout region EPR is not limited to this and may be changed according to the distance between the HMD  10  (specifically, the camera  61 ) and a predetermined target object (e.g., the operation panel  78  of the printer  70 ) included in the frame image represented by the frame image data FM 1  as long as the cutout region EPR is a region smaller than the image pickup region CPR. 
     In the processing mode, the cutout-position setting section  641  ( FIG. 5 ) sets a center position of the cutout region EPR on the basis of a region of attention that should be paid attention. The condition determining section  644  determines whether a movement of the camera  61  detected according to the detection information DT 1  of the nine-axis sensor  66  satisfies a predetermined condition specified in the condition table  621 . The condition determining section  644  determines whether the processing start data SD is given to the frame image data FM 1 . 
     The cutting out section  643  generates the frame image data for display FM 2  from the frame image data FM 1  using the cutout region EPR, the center position of which is set by the cutout-position setting section  641 . The frame image data for display FM 2  is stored in the storing section  620 . 
     The data transmitting section  648  transmits the plurality of frame image data for display FM 2  configuring the moving image data DM 2  stored in the storing section  620  to the PC  250  at the second frame rate FR 2  on the basis of an instruction from the data processing section  646 . A-4. Processing flow for image data executed by the CPU  640   
     A-4. Processing Flow for Image Data Executed by the CUP  640   
       FIG. 7  is a flowchart of a processing flow for image data executed by the CPU  640 . The processing flow shown in  FIG. 7  is executed after communication between the HMD  60  and the server  60  and communication between the server  60  and the PC  250  are established. 
     First, the data acquiring section  642  of the server  60  acquires, at a fixed time interval, the frame image data FM 1  and the detection information DT 1  stored in the storing section  120  of the HMD  10  and causes the storing section  620  to store the frame image data FM 1  and the detection information DT 1  (step S 10 ). 
     The condition determining section  644  determines whether the processing start data SD is given to the frame image data FM 1  (step S 15 ). When it is determined that the processing start data SD is not given to the frame image data FM 1 , the server  60  generates the frame image data for display FM 2  according to the normal mode. That is, the cutting out section  643  cuts out a frame image in the cutout region EPR, the center position Ce of which is the center RCe of the image pickup region CPR, and generates the frame image data for display FM 2  (step S 70 ). The frame image data for display FM 2  generated in step S 70  is transmitted to the PC  250  by the data transmitting section  648  (step S 84 ). 
     When it is determined that the processing start data SD is given to the frame image data FM 1 , the server  60  generates the frame image data for display FM 2  according to the processing mode. First, the cutout-position setting section  641  sets, with respect to the frame image data FM 1  given with the processing start data SD, the cutout region EPR centering on a reference cutout position Cs (step S 20 ). The cutout region EPR centering on the reference cutout position Cs is referred to as reference cutout region EPRs as well. In this embodiment, the reference cutout position Cs is a coordinate position of the center RCe of the image pickup region CPR. 
       FIG. 8  is a diagram for explaining the reference cutout region EPRs set by the cutout-position setting section  641 . In this embodiment, the cutout-position setting section  641  estimates that the center of the visual field of the user of the HMD  100  and the periphery of the center is a region of attention and sets the center of the visual field of the user as the reference cutout position Cs. That is, the cutout-position setting section  641  sets, as the reference cutout position Cs, the center RCe of the image pickup region CPR represented by the frame image data FM 1 . For example, in a work scene in which the operation panel  78  is a work target, the user sets, with reference to the image Via ( FIG. 4 ) picked up by the camera  61 , the direction of the camera  61  such that the operation panel  78  is the center RCe of the image pickup region CPR. The user selects the data processing start mark SM ( FIG. 4 ). Consequently, the frame image data FM 1  in which the operation panel  78  is disposed in the center RCe of the image pickup region CPR, that is, the frame image data FM 1  given with the processing start data SD is generated. 
     After step S 20 , the condition determining section  644  calculates the movement of the camera  61  on the basis of the detection information DT 1  of the nine-axis sensor  66  and determines whether the calculated movement satisfies the predetermined condition stored in the condition table  621  (step S 30 ). The predetermined condition includes a movement amount of the camera  61  and a time period from reference time generated from the processing start data SD. The predetermined condition is desirably set to conditions with which it is possible to determine whether the user has intentionally changed a target object on which work is performed. 
     The predetermined condition is a condition that the movement amount of the camera  61  is continuously a predetermined threshold or more for a predetermined time. The predetermined threshold is a threshold concerning at least one of a movement amount along the horizontal direction, a movement amount along the vertical direction, and movement amounts in rotating directions about aces (the X axis, the Y axis, and the Z axis). The predetermined threshold is desirably set to a value equal to or larger than a maximum shake amount of the head at the time when the user is performing work (operation) on a target object. The predetermined time is desirably set to a degree of a time period in which it is possible to presume that the user has intentionally changed a target object on which work is performed. 
     In this embodiment, the predetermined condition is a condition explained below. 
     Predetermined Condition 
     When the position of the camera  61  at reference time t 0  when the processing start data SD is generated is set as a reference position, a movement amount (an angle change) in a rotating direction of the camera  61 , the absolute value of which is equal to or larger than θa, continuously occurs for a predetermined time Pt or more centering on the vertical direction. 
     The predetermined time Pt is set in a range of, for example, 2 to 6 seconds. 
     If the condition determining section  644  determines that the movement satisfies the predetermined condition (YES in step S 30 ), processing in step S 60  is executed. That is, the cutout section  643  sets a center position of a cutout region for cutting out a frame image to the reference cutout position Cs set in advance and generates the frame image data for display (the standard image data) FM 2  (step S 60 ). That is, the cutout section  643  cuts out, in the reference cutout region EPRs, the frame image represented by the frame image data FM 1  and generates the frame image data for display FM 2 . The frame image data for display FM 2  generated using the reference cutout region EPRs is referred to as standard image data FM 2   s  as well. The standard image data FM 2   s  generated instep S 60  is transmitted to the PC  250  by the data transmitting section  648  (step S 83 ). 
     If the condition determining section  644  determines that the motion does not satisfy the predetermined condition (NO in step S 30 ), step S 40  is executed. That is, the cutout section  643  shifts the center position of the cutout region from the reference cutout position Cs and generates the frame image data for display FM 2  such that the movement of the camera  61  is not reflected on the frame image for display FM 2  (step S 40 ). The center position of the cutout region shifted from the reference cutout position Cs is referred to as post-correction cutout position Ct as well. A cutout region centering on the post-correction cutout position Ct is referred to as post-correction cutout region EPRt as well. The frame image data for display FM 2  generated using the post-correction cutout region EPRt is referred to as corrected image data FM 2   t  as well. In this embodiment, the center position of the cutout region on the frame image data FM 1  is shifted from the reference cutout position Cs by an amount of an intra-frame movement in the frame image data FM 1  corresponding to the movement of the camera  61  from reference time t 0 . The intra-frame movement may be calculated by comparing the frame image data FM 1  at reference time t 0  and the frame image data FM 1  of a processing target. Alternatively, when the distance between the camera  61  and a target object of attention (e.g., the operation panel  78 ) is a known value, the intra-frame movement may be calculated on the basis of the movement of the camera  61 . The corrected image data FM 2   t  generated in step S 40  is transmitted to the PC  250  by the data transmitting section  648  (step S 82 ). 
     A-5. Specific Examples of the Reference Cutout Region EPRs and the Post-Correction Cutout Region EPRt 
       FIG. 9  is a diagram for explaining a processing flow.  FIG. 10  is a diagram showing a change of a movement in a horizontal plane of the camera  61 .  FIG. 11  is a diagram showing a relation between the image pickup region CPR and the reference cutout region EPRs at reference time t 0 .  FIG. 12  is a diagram showing a relation between the image pickup region CPR and the cutout region EPR at time t 1 .  FIG. 13  is a diagram showing a relation between the image pickup region CPR and the cutout region EPR at time t 8 . 
     After operating the operation panel  78  of the printer  70 , a user  99  operates the spindle bearing  75  ( FIG. 2 ) and thereafter further operates the operation panel  78 . As shown in  FIG. 9 , when the user  99  operates the operation panel  78  of the printer  70 , a visual line of the user  99  is directed to the vicinity of an arrow Y 1 . When operating the spindle bearing  75 , the user  99  turns the head and the visual line is directed to the vicinity of an arrow Y 2 . In  FIG. 10 , in a period of time t 0  to time t 6 , the user  99  operates the operation panel  78 . In a period of time t 7  to time t 9 , the user  99  operates the spindle bearing  75 . Further, at time t 10  and subsequent time, the user  99  operates the operation panel  78 . In a period of time t 8  to time t 9 , the movement of the camera  61  satisfies the predetermined condition. In a period of time t 2  to time t 5 , responding to ambient sound (e.g., noise), after suddenly turning the head in order to view the direction of the sound, the user  99  changes the direction of the visual line to the direction of the operation panel  78  again. 
     As shown in  FIG. 11 , the processing start data SD is given to the frame image data FM 1  at time t 0 . Therefore, the cutout-position setting section  641  sets, as the reference cutout position Cs, the center RCe of the image pickup region CPR represented by the frame image data FM 1  (step S 20  in  FIG. 7 ). The detection information DT 1  of the nine-axis sensor  66  at time t 0  represents reference information for calculating the movement of the camera  61 . That is, the condition determining section  644  determines whether the movement of the camera  61  at time t 0  and subsequent time based on the position of the camera  61  at time t 0  satisfies the predetermined condition. 
     As shown in  FIG. 10 , the camera  61  at time t 2  further rotates and moves by θ 1  clockwise than the camera  61  at reference time t 0 . θ 1  is smaller than the predetermined threshold θa. The condition determining section  644  calculates on the basis of the detection information DT 1  that the camera  61  has rotated and moved by θ 1  clockwise and determines that the calculated movement amount θ 1  of the camera  61  is smaller than the predetermined threshold θa. That is, the condition determining section  644  determines that the movement of the camera  61  at time t 2  does not satisfy the predetermined condition (NO in step S 30 ). 
     The cutout-position setting section  641  sets the post-correction cutout position Ct with respect to the frame image data FM 1  at time t 2 . That is, as shown in  FIG. 12 , the cutout-position setting section  641  shifts the center position of the cutout region from the reference cutout position Cs in a direction opposite to the movement (+θ1) of the camera  61  to set the post-correction cutout position Ct. In this embodiment, the cutout-position setting section  641  shifts the cutout position from the reference cutout position Cs by an amount of a movement (−L1) opposite to the movement of the camera  61  in a frame image (the frame image represented by the frame image data FM 1 ) to set the post-correction cutout position Ct. When the post-correction cutout position Ct is set, the post-correction cutout region EPRt in a fixed range centering on the post-correction cutout position Ct is set. The cutout section  643  cuts out, in the post-correction cutout region EPRt, the frame image represented by the frame image data FM 1  and generates the corrected image data FM 2   t . The operation panel  78  is located in the center of the corrected image data FM 2   t  such that the movement of the camera  61  is cancelled. Therefore, the frame image for display at time t 2  is displayed on the display section  251  of the PC  250  like an image at the time when the camera  61  does not move from reference time t 0 . In a period of time t 3  to time t 4  when a movement amount of the camera  61  is equal to or larger than the predetermined value θa, since the condition of the predetermined time Pt is not satisfied, it is determined that the movement of the camera  61  does not satisfy the predetermined condition. In this case, like the data processing of the frame image data FM 1  at time t 2 , the center position of the cutout region is shifted by the data processing section  646  by an amount corresponding to the movement of the camera  61 . Note that, when a part of the post-correction cutout region EPRt is located outside the range of the image pickup region CPR, image data in a region located outside the region may be changed to black date or white data. The image data in the region located outside the region may be generated on the basis of image data of a region located within the range. 
     At time t 8  in  FIG. 10 , the condition determining section  644  determines that the movement of the camera  61  satisfies the predetermined condition. In this case, as shown in  FIG. 13 , the cutout-position setting section  641  sets the reference cutout position Cs. The data processing section  646  generates the standard image data FM 2   s  in the reference cutout region EPRs centering on the reference cutout position Cs. That is, a frame image for display at time t 8  is an image reflecting the movement of the camera  61  from reference time t 0 . That is, an image including the spindle bearing  75  is displayed on the display section  251  of the PC  250  as a frame image for display. 
     As shown in  FIG. 10 , at time t 9  and subsequent time, the movement of the camera  61  does not satisfy the predetermined condition. Therefore, the data processing section  646  generates the corrected image data FM 2   t  using the post-correction cutout region EPRt. 
     As explained above, according to the first embodiment, it is possible to, while causing the display section  251  to display the moving image including the target object (e.g., the operation panel  78 ), a shake of the image displayed on the display section  251  due to the movement of the camera  61  not satisfying the predetermined condition. The predetermined condition includes the condition concerning the time, that is, the predetermined time. Consequently, even when the movement amount of the camera  61  is equal to or larger than the predetermined threshold, when the period of time in which the movement amount is equal to or larger than the predetermined threshold is shorter than the predetermined time, the center position Ce of the cutout region EPR is shifted from the reference cutout position Cs such that the movement of the camera  61  is reflected. Consequently, the movement of the camera  61  equal to or larger than the predetermined threshold that occurs in a period of time shorter than the predetermined time is not reflected on the image displayed on the display section  251 . Therefore, it is possible to further reduce the shake of the image displayed on the display section  251 . That is, even when the user suddenly moves the head, the sudden movement is not reflected on the image displayed on the display section  251 . 
     According to the first embodiment, the cutout-position setting section  641  sets the reference cutout position Cs on the basis of the region of attention that should be paid attention. Consequently, it is possible to easily set the reference cutout position Cs on the basis of the region of attention. According to the first embodiment, the server  60  includes the data processing section  646  and the storing section  620 . Consequently, it is unnecessary to implement the functions of the data processing section  646  and the storing section  620  in the HMD  100 . Therefore, it is possible to reduce the costs of the HMD  100 . 
     B. Second Embodiment 
     B-1. Configurations of an HMD and a Server 
       FIG. 14  is a block diagram functionally showing the configuration of an HMD  100   a  in a second embodiment. The HMD  100   a  in the second embodiment is different from the HMD  100  ( FIG. 3 ) in the first embodiment in that the HMD  100   a  includes a TOF sensor section  62  and a distance detecting section  164  anew. The other components of the HMD  100   a  in the second embodiment are the same as the components of the HMD  100  in the first embodiment. Therefore, the same components are denoted by the reference numerals and signs same as those in the first embodiment and explanation of the components is omitted. The TOF sensor section  62  includes a light receiving element and an infrared LED. 
     The distance detecting section  164  is a distance image sensor that calculates, concerning reflected light of infrared ray detected by the TOF sensor section  62 , using a TOF (Time of Flight) system, a time period from emission of the infrared ray from an infrared LED until reflection of the infrared ray on a specific target object and reception of the infrared ray by the light receiving element of the TOF sensor section  62  to detect a distance (a target object distance) from the image display section  20 , in which the TOF sensor section  62  is disposed, to the specific target object. 
     Note that a configuration for detecting the distance is not limited to the configuration explained above. Various other methods explained below can be adopted. 
     First another distance detecting method: The distance detecting section  164  detects the target object distance on the basis of the position of the image display section  20  specified by the GPS module  134  and the position of the target object stored in the storing section  120  in advance. 
     Second another distance detecting method: When two cameras  61  are provided at an interval, the target object distance is detected using the trigonometry on the basis of the direction of the image display section  20  (the direction of the visual line of the user) detected by the nine-axis sensor  66  and two images including the target object picked up by the two cameras  61 . 
     Third another distance detecting method: The distance detecting section  164  compares the actual size of the target object and the size of the target object in the frame image to detect the target object distance. In this case, data representing the actual size of the target object is stored in the storing section  120 . 
     Distance data DL of the target object distance is given with time data representing the present time and stored in the storing section  120 . The distance data DL is transmitted to a server  60   a . Note that the distance data DL may be given to the frame image data FM generated at the same time. 
       FIG. 15  is a block diagram functionally showing the configuration of a server  60   a  in the second embodiment. The server  60   a  in the second embodiment is different from the server  60  ( FIG. 5 ) in the first embodiment in that the server  60   a  stores the distance data DL in a storing section  620   a  anew and a data processing section  646   a  includes an interpolation processing section  647  and a cutout-region setting section  645  anew. The other components of the server  60   a  in the second embodiment are the same as the components of the server  60  in the first embodiment. Therefore, the same components are denoted by reference numerals and signs same as those in the first embodiment and explanation of the components is omitted. 
     The interpolation processing section  647  executes processing for smoothing a movement of an entire moving image displayed on the display section  251 . The interpolation processing section  647  generates a new frame image for display (frame image for interpolation display) inserted between two frame images for display represented by corrected image data FM 2   t  generated when the movement of the camera  61  does not satisfy a predetermined condition and standard image data FM 2   s  generated when the movement of the camera  61  satisfies the predetermined condition. Interpolation processing by the interpolation processing section  647  is executed between step S 30  and step S 60  shown in  FIG. 7 . Details of the interpolation processing section  647  are explained below. 
     The cutout-region setting section  645  changes the size of the cutout region EPR according to the distance data DL detected by the distance detecting section  164 . In this embodiment, the cutout region EPR is set larger as the target object distance represented by the distance data DL is larger such that the size of the target object displayed on the display section  251  is substantially fixed. Note that the cutout region EPR may be increased in size stepwise as the target object distance increases in size. Details of the cutout-region setting section  645  are explained below. 
     B-2. Processing Content of the Interpolation Processing Section 
       FIGS. 16A to 16C  are diagrams for explaining an interpolation processing method executed by the interpolation processing section  647 .  FIG. 16A  shows the outside world SC in the front of the user  99 .  FIG. 16B  shows frame images displayed on the display section  251  of the PC  250  at respective times.  FIG. 16C  is a diagram for explaining processing contents of the data processing section  646   a.    
     As shown in  FIG. 16A , in the outside world SC, a first target object M 1 , a second target object M 2 , and a third target object M 3  are disposed in order from the right. At reference time t 0  to time t 2 , the user  99  performs work of the first target object M 1 . Subsequently, the user  99  moves from the right side to the left side as indicated by an arrow Ya. At time t 3  and subsequent time, the user  99  performs work of the second target object M 2 . It is assumed that, at reference time t 0  to time t 2 , the movement of the camera  61  does not satisfy the predetermined condition and, at time t 3  and subsequent time, the movement of the camera  61  satisfies the predetermined condition. The data processing section  646  transmits the frame image data for display FM 2  to the PC  250  at the second frame rate FR 2  in order to cause the display section  251  to display a frame image at every predetermined interval Δt. 
     In a period of reference time t 0  to time t 2 , the cutout section  643  generates the corrected image data FM 2   t  from the frame image data FM 1  using the post-correction cutout region EPRt. The corrected image data FM 2   t  is transmitted to the PC  250  by the data transmitting section  648 . The PC  250  displays a first image represented by the corrected image data FM 2   t . That is, a moving image in which the position of the first target object M 1  does not change according to the movement of the camera  61  is displayed on the display section  251 . As shown in  FIG. 16B , an image in which the first target object M 1  is the center of the display section  251  is displayed until time t 2 . 
     At time t 3  and subsequent time, the cutout section  643  generates the standard image data FM 2   s  from the frame image data FM 1  using the reference cutout region EPRs. The standard image data FM 2   s  is transmitted to the PC  250  by the data transmitting section  648 . The PC  250  displays a second image represented by the standard image data FM 2   s . As shown in  FIG. 16B , at time t 3 , an image in which the second target object M 2  is the center of the display section  251  is displayed. That is, when the interpolation processing section  647  does not function, the second image at time t 3  is suddenly displayed on the display section  251  following the first image at time t 2 . This causes the instructor on the display section  251  side to feel a sense of discomfort. Time t 2  is a point in time when the movement of the camera  61  does not satisfy the predetermined condition. Time t 3  is a point in time when the movement of the camera  61  satisfies the predetermined condition. 
     Therefore, the interpolation processing section  647  executes interpolation image processing as explained below. First, the interpolation processing section  647  selects at least one data out of frame image data for interpolation serving as the plurality of frame image data FM 1  picked up in a period of time t 2  to time t 3  stored in the storing section  620   a . In  FIG. 16C , the interpolation processing section  647  selects the frame image data FM 1  at time tg, time tm, and time ty. Subsequently, the interpolation processing section  647  cuts out, in the reference cutout region EPRs, a frame image of the selected frame image data FM 1  and generates interpolation image data FM 2   m . The interpolation image data FM 2   m  is stored in the storing section  620   a . The interpolation image data FM 2   m  is image data to be displayed on the display section  251 . Therefore, the interpolation image data FM 2   m  is referred to as “frame image data for interpolation display FM 2   m ”. The interpolation image data FM 2   m  represents an image reflecting the movement of the camera  61 . 
     The interpolation processing section  647  causes the storing section  620   a  to store the generated interpolation image data FM 2   m  at time tg, time tm, and time ty in this order between first frame image data for display (the first image) and second frame image data for display (the second image) arranged in time series. That is, the interpolation processing section  647  inserts the interpolation image data FM 2   m  between the corrected image data FM 2   t  at time t 2  and the standard image data FM 2   s  at time t 3  transmitted in time series at the second frame rate FR 2  and causes the data transmitting section  648  to transmit these image data to the PC  250 . That is, in the period of time t 2  to time t 3 , an image reflecting the movement of the camera  61  is displayed on the display section  251  at a frame rate higher than the second frame rate FR 2 . Specifically, at time t 2  to time t 3 , a fast-forwarding moving image, that is, a moving image in which an image is smoothly switched from the first target object M 1  to the second target object M 2  is displayed on the display section  251 . Consequently, a movement of the image displayed on the display section  251  in the period of time t 2  to time t 3  is smoothed. It is possible to prevent the instructor viewing the display section  251  from feeling a sense of discomfort concerning the moving image. It is possible to generate the interpolation image data FM 2   m  effectively using the frame image not used at the second frame rate FR 2 . 
     B-3. Another Processing Method of the Interpolation Processing Section 
     The interpolation processing method executed by the interpolation processing section  647  is not limited to the interpolation processing method explained above. The interpolation processing method may be another processing method as long as the interpolation image data FM 2   m  for interpolating a difference between the first image and the second image can be generated when the second image represented by the second frame image data for display generated when the movement of the camera  61  satisfies the predetermined condition is displayed on the PC  250  after the first image represented by the first frame image data for display generated when the movement of the camera  61  does not satisfy the predetermined condition. A specific example of the other processing method executed by the interpolation processing section  647  is explained below. 
       FIGS. 17A and 17B  are diagrams for explaining another interpolation processing method executed by the interpolation processing section  647 .  FIG. 17A  shows the outside world SC in the front of the user  99 .  FIG. 17B  is a diagram for explaining processing contents of the data processing section  646   a.    
     At reference time t 0  to time t 2 , the user  99  performs work of the first target object M 1 . Subsequently, the user  99  moves from the right side to the left side by a distance L and, at time t 3  and subsequent time, performs work of the second target object M 2 . A distance on the frame image data FM 1  equivalent to the distance Lisa distance Lp. It is assumed that, at reference time t 0  to time t 2 , the movement of the camera  61  does not satisfy the predetermined condition and, at time t 3  and subsequent time, the movement of the camera  61  satisfies the predetermined condition. The data processing section  646   a  transmits the frame image data for display FM 2  to the PC  250  at the second frame rate FR 2  in order to cause the display section  251  to display the frame image at every predetermined interval Δt. 
     The interpolation processing section  647  performs, while maintaining the second frame rate FR 2 , interpolation of the frame image data FM 1  in a boundary portion between a point in time when the movement of the camera  61  does not satisfy the predetermined condition and a point in time when the movement of the camera  61  satisfies the predetermined condition. The number of frames of the frame image on which the interpolation processing is executed by the interpolation processing section  647  may be set in advance or may be variable according to the movement amount of the camera  61 . In this embodiment, the number of frames of the frame image on which the interpolation processing is executed is two. Note that, when the number of frames on which the interpolation processing is performed is varied according to the movement amount of the camera  61 , it is desirable to increase the number of frames as the movement amount increases. Consequently, the movement of the image displayed on the display section  251  is further smoothed. 
     From time when the movement of the camera  61  satisfies the predetermined condition, the interpolation processing section  647  sets, with respect to the two frame image data FM 1  at time t 3  and time t 4  arranged in time series, the center position Ce of the cutout region EPR to interpolate the movement of the camera  61 . Specifically, the interpolation processing section  647  sets, with respect to the frame image data FM 1  at time t 3 , as the center position Ce, a position shifted from the reference cutout position Cs by (2×Lp)/3 in a direction opposite to the movement of the camera  61 . The interpolation processing section  647  cuts out the frame image data FM 1  in the cutout region EPR centering on the set center position Ce and generates the interpolation image data FM 2   m . The interpolation processing section  647  sets, with respect to the frame image data FM 1  at time t 4 , as the center position Ce, a position shifted from the reference cutout position Cs by (1×Lp)/3 in the direction opposite to the movement of the camera  61 . The interpolation processing section  647  cuts out the frame image data FM 1  in the cutout region EPR centering on the set center position Ce and generates the interpolation image data FM 2   m . Note that, in the interpolation image data FM 2   m , since the cutout region EPR is located outside the range of the image pickup region CPR as well, an outer side portion of the image pickup region CPR in the cutout region EPR is generated by predicting an image on the basis of the frame image before or after time t 3 . 
     In this way, the interpolation processing section  647  sets, with respect to the frame image data FM 1 , the center position Ce by shifting the center position Ce from the reference cutout position Cs by a distance (a shift amount) calculated by the following relational expression (1) in the direction opposite to the movement of the camera  61 .
 
Shift amount  Ls =( Nn×Lp )/( Fn+ 1)  (1)
 
     In the relational expression (1), Nn represents order counted from the last of frames arranged in time series on which the interpolation processing is performed, Lp represents a distance on the frame image data FM 1  equivalent to the movement amount L of the camera  61 , and Fn represents the number of frames on which the interpolation processing is performed. 
     In this way, the interpolation processing section  647  sets, with respect to at least one frame image data FM located, in time series, between the frame image data FM 1  serving as the first frame image data and the frame image data FM 1  serving as the second frame image data, the center position Ce to interpolate the movement of the camera  61  and generates the interpolation image data FM 2   m . Consequently, the movement of the image displayed on the display section  251  in the period of time t 2  to time t 5  is smoothed. It is possible to prevent the instructor viewing the display section  251  from feeling a sense of discomfort concerning a moving image. It is possible to, while causing the display section  251  to display the moving image at the second frame rate FR 2 , prevent the instructor viewing a display section  25  from feeling a sense of discomfort concerning the moving image. 
     Note that the interpolation processing shown in  FIGS. 17A and 17B  may be executed on the frame image data FM 1  in which it is determined that the movement of the camera  61  does not satisfy the predetermined condition. That is, the interpolation processing may be executed between step S 30  and step S 40  shown in  FIG. 7 . For example, in the following explanation, the interpolation processing is performed on the frame image data FM 1  at time t 1  and time t 2 , which is data in a boundary portion between a point in time when the movement of the camera  61  does not satisfy the predetermined condition and a point in time when the movement of the camera  61  satisfies the predetermined condition. In this case, with respect to the frame image data FM 1  at time t 2 , a position shifted from the post-correction cutout position Ct by (2×Lp)/3 in a direction same as the movement of the camera  61  is set as the center position Ce. With respect to the frame image data FM 1  at time t 1 , a position shifted from the post-correction cutout position Ct by (1×Lp)/3 in the direction same as the movement of the camera  61  is set as the center position Ce. 
       FIGS. 18A and 18B  are diagrams for explaining processing contents of the cutout-region setting section  645 . The target object distance represented by the distance data DL is larger in  FIG. 18A  than in  FIG. 18B . In this case, the cutout-region setting section  645  sets the cutout region EPR centering on the center position Ce larger as the target object distance is larger. Consequently, it is possible to suppress the size of the target object (e.g., the operation panel  78 ) displayed on the display section  251  from greatly fluctuating. 
     According to the second embodiment, components same as the components in the first embodiment achieve the same effects. According to the second embodiment, since the server  60   a  includes the interpolation processing section  647 , it is possible to suppress contents of the image displayed on the display section  251  from being suddenly switched in the boundary portion between the point in time when the predetermined condition is not satisfied and the point in time when the predetermined condition is satisfied. 
     C. Modification of the Cutout-Position Setting Section 
     In the first and second embodiments, the cutout-position setting section  641  ( FIGS. 5 and 15 ) sets, as the reference cutout position Cs, the center RCe of the image pickup region CPR represented by the frame image data FM 1 . However, a method of setting the reference cutout position Cs is not limited to this. For example, the reference cutout position Cs may be set by any one of first to third other setting methods explained below. 
       FIG. 19  is a diagram for explaining the first other setting method for the reference cutout position Cs. The cutout-position setting section  641  determines, as a region of attention AA, overlapping image regions among candidate regions of attention FAA in a plurality of frame images FM 1   a  to FM 1   d  picked up in a predetermined period (time t 1   a  to time t 1   d : e.g., 1 to 10 seconds) after the data processing start mark SM is selected. The cutout-position setting section  641  sets the center position of the determined region of attention AA as the reference cutout position Cs. The candidate regions of attention FAA are fixed regions smaller than the frame images FM 1   a  to FM 1   d  centering on a center position Rce of the frame images FM 1   a  to FM 1   d . The cutout-position setting section  641  discriminates, with image processing, an image of the region of attention AA present in the candidate region of attention FAA of the frame image FM 1   a  at certain time (e.g., time t 1   a ). The cutout-position setting section  641  sets, as a reference cutout position, the center position of the region of attention AA in the frame image FM 1   a . In this way, according to the first other setting method, it is possible to easily set the region of attention AA on the basis of overlapping data without depending on operation by the user or the instructor. 
     The first other setting method is not limited to the method explained above. The reference cutout position Cs may be determined as the region of attention AA on the basis of a direction of the visual line or an opening/closing state of the pupils of the user of the HMD  10 . For example, a sensor or a camera that detects the direction of the visual line or the state of the pupils of the user is provided in the HMD  100  anew. As a method of determining the region of attention AA on the basis of the direction of the visual line, for example, when the HMD  100  determines that the direction of the visual line of the user in within a fixed region for a predetermined time, the fixed region may be determined as the region of attention AA. As a method of setting the region of attention AA on the basis of the opening/closing state of the pupils, for example, the opening/closing state of the pupils is detected by the sensor or the camera and a fixed region to which the user pays attention is estimated on the basis of a detection result. The estimated fixed region is determined as the region of attention AA. 
       FIG. 20  is a diagram for explaining the second other setting method for the reference cutout position Cs. The cutout-position setting section  641  sets a cutout center position by determining, as a region of attention, a region including a designated target object designated from the outside (e.g., the instructor). For example, the instructor of the PC  250  causes the user of the HMD  100  to designate a target object that the user should pay attention (a designated target object) and causes the image display section  20  to display the designated target object as the image VIa. In  FIG. 20 , an image of the display  79  is displayed on the image display section  20 . The user moves a frame-like image  97 , which represents the region of attention displayed on the image display section  20 , using the cross key  16  ( FIG. 1 ) such that the display  79  present in an outside scene is located within the frame image  97 . The frame image  97  includes a mark  101  indicating the center position of the frame image  97 . After locating the operation panel  78  including the display  79  within the frame image  97 , the user selects the data processing start mark SM displayed as an image. Consequently, the center of the frame image  97  is set in the reference cutout position Cs. In this way, according to the second other setting method, the region including the designated target object designated from the outside can be set as the region of attention. Since the image of the designated target object is displayed on the image display section  20 , the user can easily recognize the designated target object by visually recognizing the image displayed on the image display section  20 . 
     In the second other setting method, the region of attention is set by designating the designated target object using the frame image  97 . However, a method of setting the region of attention is not limited to this. Another method capable of designating the designated target object may be adopted instead of the method of designating the designated target object using the frame image  97 . For example, a colored image (a color image) through which the outside scene can be transmitted is displayed on the image display section  20 . The color image is moved such that the operation panel  78  serving as the designated target object is located within the color image. The center of the color image is set in the reference cutout position Cs by selecting the data processing start mark SM. As the exterior shape of the color image, various shapes such as a rectangular shape and a circular shape can be adopted. 
       FIGS. 21A and 21B  are diagrams for explaining the third other setting method for the reference cutout position Cs.  FIG. 21A  is a diagram for explaining an object-of-attention table  122 .  FIG. 21B  is a diagram for explaining a setting method for the reference cutout position Cs. 
     As shown in  FIG. 21A , the storing section  120  of the HMD  100  includes anew the object-of-attention table  122  that stores an object of attention. The object-of-attention table  122  includes, for each target object of attention, characteristic information for specifying the target object of attention. The characteristic information is information such as the shape, the size, and the color of the target object of attention. In the object-of-attention table  122  shown in  FIG. 21A , the characteristic information is stored for each of the sections (e.g., the display  79 ) of the printer  70 . 
     The cutout-position setting section  641  detects, with pattern matching, one target object of attention stored in the object-of-attention table  122  out of the frame image data FM. Then, the cutout-position setting section  641  determines, as the region of attention AA, a region including the detected target object of attention. The cutout-position setting section  641  sets the center position of the region of attention AA as the reference cutout position Cs. For example, as shown in  FIG. 21B , the cutout-position setting section  641  detects the operation panel  78  out of the frame image data FM. The cutout-position setting section  641  sets, as the reference cutout position Cs, the center position of the region of attention AA including the operation panel  78 . The setting of the reference cutout position Cs is recognized as reception of the processing start data SD. The processing in step S 20  ( FIG. 7 ) and subsequent steps is executed by the servers  60  and  60   a . Note that a detection region DA of the frame image data FM 1  for detecting the target object of attention is desirably a region smaller than the image pickup region CPR and a region including the center position of the image pickup region CPR. Consequently, it is possible to prevent the target object of attention from being detected when the target object of attention is located at an end of the image pickup region CPR. Therefore, it is possible to prevent the reference cutout position Cs from being set near the end of the image pickup region CPR. According to the third other setting method, it is possible to set the reference cutout position Cs by automatically detecting the target object of attention with the cutout-position setting section  641 . 
     D. Modifications 
     In the embodiments, a part of the components implemented by hardware may be replaced with software. Conversely, a part of the components implemented by software may be replaced with hardware. Besides, modifications explained below are also possible. 
     Modification 1 
     In the first and second embodiments, the data processing elements (the storing sections  620  and  620   a  and the data processing sections  646  and  646   a ) for generating the frame image data for display FM 2  are provided in the servers  60  and  60   a  that relay data between the HMD  100  and the PC  250 . However, the data processing elements are not limited to this. For example, the storing sections  620  and  620   a  and the data processing sections  646  and  646   a  may be provided in the HMD  100  or may be provided in the PC  250 . Consequently, it is possible to perform data processing for moving image data using a single device (e.g., the HMD  100 ). 
     The information processing device including the data processing elements (the data processing sections  646  and  646   a  and the storing sections  620  and  620   a ) for generating the frame image data for display FM 2  may be connected to at least one of the HMD  100  and the display section  251  ( FIG. 1 ) by a wired cable. One of the HMD  100  and the PC  250  may include the data processing elements. The HMD  100  and the PC  250  may be connected by a wired cable. 
     Modification 2 
     In the embodiments, the HMD  100  is used as an example of the image display device. However, the image display device is not limited to this. The image display device only has to include at least an image pickup section that picks up a moving image and a sensor for detecting a movement of the image pickup section. The image display device may be, for example, a video camera, a smartphone, a tablet terminal, or a robot. The image display device does not have to have a function of displaying an image. In this case, the image display device can be called moving-image acquiring device as well. The display system  1  is explained using the remote support system as an example. However, the display system  1  is not limited to this. For example, the invention may be applied to, for example, a system that performs a live broadcast of baseball games. The configurations of the HMD  100 , the servers  60  and  60   a , and the PC  250  can be optionally decided without departing from the spirit of the invention. For example, addition, deletion, conversion, and the like of the components can be performed. 
     In the embodiments, the HMD  100  is the transmission-type HMD of the binocular type. However, the HMD  100  may be an HMD of a monocular type. The HMD  100  may be configured as a non-transmission-type HMD with which transmission of an outside scene is blocked in a state in which the user wears the HMD. The HMD  100  may be configured as a video see-through HMD obtained by mounting a camera on the non-transmission-type HMD. For example, the right optical-image display section  26  and the left optical-image display section  28  ( FIG. 1 ) included in the image display section  20  may be formed smaller than in the embodiments and respectively disposed, for example, obliquely above and obliquely below the left and right eyes of the user during the wearing of the HMD. In this way, the optical-image display sections only have to be disposed near the eyes of the user. The size of the optical members forming the optical-image display sections may be any size. The optical-image display sections may cover only a part of the eyes of the user. In other words, the optical-image display sections do not have to completely cover the eyes of the user. An HMD of a pupil division type may be adopted as the invention. In the HMD of the pupil division type, light from the outside world present ahead of the optical-image display sections enters the pupils from portions that do not cover the optical-image display sections. For example, as the image display section, instead of the image display section worn like eyeglasses, a normal flat display device (a liquid crystal display device, a plasma display device, an organic EL display device, etc.) may be adopted. In this case, as in the embodiments, the control section and the image display section may be connected via a wired signal transmission line or may be connected via a wireless signal transmission line. Consequently, the control section can also be used as a remote controller of the normal flat display device. For example, as the image display section, an image display section of another shape such as an image display section worn like a cap may be adopted instead of the image display section worn like eyeglasses. As earphones, an ear hook type or a headband type may be adopted. The earphones may be omitted. For example, the image display section may be configured as a head-up display (HUD) mounted on vehicles such as an automobile and an airplane and other transportation means. For example, the image display section may be configured as an HMD incorporated in body protective equipment such as a helmet. For example, the image display section may be configured as a portable hand held display. 
     Modification 3 
     In the first and second embodiments, the cutout-position setting section  641  sets the post-correction cutout position Ct on the basis of the detection information DT 1  of the nine-axis sensor  66 . However, the setting of the post-correction cutout position Ct is not limited to this. For example, the cutout-position setting section  641  may set the post-correction cutout position Ct on the basis of a stationary movement of the camera  61  (i.e., a stationary shake of the head of the user of the HMD  100 ) measured in advance. 
     Modification 4 
     In the first and second embodiments, the center RCe of the image pickup region CPR is set as the reference cutout position Cs. However, the reference cutout position Cs is not limited to this. For example, the reference cutout position Cs may be designated by the user or the instructor or may be set in a position shifted from the center RCe of the image pickup region CPR. 
     Modification 5 
     In the second embodiment, the distance detecting section  164  sets the cutout region EPR larger as the target object distance represented by the distance data DL is larger. However, the cutout region EPR is not limited to this. For example, the distance detecting section  164  may set the cutout region EPR smaller as the target object distance represented by the distance data DL is larger. 
     Instead of the distance between the camera  61  and the predetermined target object (the target object distance), the size of the cutout region EPR may be changed according to moving speed of the head of the user of the HMD  100 . The moving speed of the head is detected by the nine-axis sensor  66  or calculated by the CPU  140  on the basis of a detection result of the nine-axis sensor  66 . For example, the cutout region may be set larger as the moving speed is higher. Consequently, since a region in a wide range can be displayed on the display section  251 , the instructor can more easily recognize the movement of the head. 
     Modification 6 
     In the first and second embodiments, the cutout-position setting section  641  sets the post-correction cutout position Ct by shifting the reference cutout position Cs by the movement amount from the reference position of the camera  61  in the frame image in the direction opposite to the movement of the camera  61 . However, a setting method for the post-correction cutout position Ct is not limited to this. For example, the cutout-position setting section  641  may set the post-correction cutout position Ct to make it possible to suppress the movement of the camera  61  from being reflected on the display section  251 . Specifically, the cutout-position setting section  641  may set the post-correction cutout position Ct by shifting the reference cutout position Cs by a distance smaller than the movement amount (e.g., ⅓ or ⅔ of the movement amount) from the reference position of the camera  61  in the direction opposite to the movement of the camera  61 . 
     Modification 7 
     When the display device is an HMD of a binocular type or is capable of three dimensionally displaying an image, the display device may stereoscopically display the image as explained below. Specifically, the display device may detect, with the distance detecting section  164 , the distance from the predetermined target object to the image pickup section, generate respective frame images visually recognized by the left and right eyes of the instructor with a parallax corresponding to a detection result added to the frame images, and stereoscopically display the image. 
     Modification 8 
     In the embodiments, the camera  61  of the HMD  100  transmits the plurality of frame image data FM 1  continuing in time series to the servers  60  and  60   a  as the moving image data DM 1 . The data processing sections  646  and  646   a  of the servers  60  and  60   a  perform the data processing on the moving image data DM 1 . However, the camera  61  of the HMD  100  and the data processing sections  646  and  646   a  are not limited to this. For example, the camera  61  of the HMD  100  may pick up images in every predetermined period and transmit a picked-up plurality of images to the servers  60  and  60   a . The data processing sections  646  and  646   a  of the servers  60  and  60   a  may perform the data processing on a plurality of image data. 
     Modification 9 
     The invention is not limited to the embodiments, the examples, and the modifications explained above and can be implemented as various configurations without departing from the spirit of the invention. For example, the technical features in the embodiments, the examples, and the modifications corresponding to the technical features in the aspects described in the summary can be replaced or combined as appropriate in order to solve a part or all of the problems or attain a part or all of the effects. Unless the technical features are explained in this specification as essential technical features, the technical features can be deleted as appropriate. 
     The entire disclosure of Japanese Patent Application No. 2015-153170, filed Aug. 3, 2015 is expressly incorporated by reference herein.