Abstract:
A non-transitory storage medium stores instructions executable by a display device including an image taking device and a display. The instructions cause the display device to perform: displaying a real-space image being taken by the image taking device; displaying a content disposed in an augmented reality space and the real-space image in combination, when a marker associated with the content exists in the real-space image; keeping displaying the content, when an instruction for keeping displaying the content is provided with the content being displayed; displaying the content when the instruction is not provided and when the marker exists in the real-space image; and not displaying the content when the instruction is not provided and when the marker does not exist in the real-space image.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority from Japanese Patent Application No. 2014-018533, which was filed on Feb. 3, 2014, the disclosure of which is herein incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a display device and a non-transitory storage medium storing a plurality of instructions executable by a computer of the display device. 
         [0004]    2. Description of the Related Art 
         [0005]    There is known a technique in which when an image of a marker attached to a subject device is taken by a camera, an image taken by the camera and a help object associated with the marker are combined with each other and displayed using an AR (Augmented Reality) technique. 
       SUMMARY 
       [0006]    In the technique described above, when the image taking of the marker has ceased, the help object disappears. To keep displaying the help object, a user needs to keep taking the image of the marker with the camera. In the case where the user performs operations or works while viewing the help object, however, if the camera is moved, or the marker is hidden by a user&#39;s hand, for example, the user cannot take the image of the marker, leading to disappearance of the help object being viewed by the user. 
         [0007]    An aspect of the disclosure relates to a display device and a non-transitory storage medium storing a plurality of instructions executable by a computer of the display device, each allowing a user to easily use a content which is combined with an image in a real space and displayed using the AR technique. 
         [0008]    In one aspect of the disclosure, a non-transitory storage medium stores a plurality of instructions executable by a computer of a display device including an image taking device and a display. The plurality of instructions, when executed by the computer, cause the display device to perform: controlling the display to display a real-space image which is being taken by the image taking device; determining whether the real-space image taken by the image taking device includes a marker; synthesizing the real-space image and a content associated with the determined marker when it is determined that the real-space image includes the marker; controlling the display to display the real-space image synthesized with the content; receiving an instruction for keeping displaying the content on the display while the real-space image synthesized with the content is displayed on the display; controlling the display to display the real-space image with the synthesized content on the display when the instruction is not received and when the real-space image taken by the image taking device includes the marker; controlling the display to display the real-space image with the synthesized content on the display when the instruction is received and when the real-space image taken by the image taking device does not include the marker; and controlling the display to disappear the content on the display while displaying the real-space image when the instruction is not received and when the real-space image taken by the image taking device does not include the marker. 
         [0009]    In another aspect of the disclosure, a display device includes: an image taking device; a display; a processor; and a memory storing a plurality of instructions. The plurality of instructions, when executed by the processor, cause the display device to perform: controlling the display to display a real-space image which is being taken by the image taking device; determining whether the real-space image taken by the image taking device includes a marker; synthesizing the real-space image and a content associated with the determined marker when it is determined that the real-space image includes the marker; controlling the display to display the real-space image synthesized with the content; receiving an instruction for keeping displaying the content on the display while the real-space image synthesized with the content is displayed on the display; controlling the display to display the real-space image with the synthesized content on the display when the instruction is not received and when the real-space image taken by the image taking device includes the marker; controlling the display to display the real-space image with the synthesized content on the display when the instruction is received and when the real-space image taken by the image taking device does not include the marker; and controlling the display to disappear the content on the display while displaying the real-space image when the instruction is not received and when the real-space image taken by the image taking device does not include the marker. 
         [0010]    It is noted that the present invention may be achieved in the form of, e.g., the display device, a controller for controlling the display device, a display system, a display method, or the storage medium storing a display program. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The objects, features, advantages, and technical and industrial significance of the present disclosure will be better understood by reading the following detailed description of the embodiments, when considered in connection with the accompanying drawings, in which: 
           [0012]      FIG. 1  is a block diagram illustrating an electric configuration of a terminal; 
           [0013]      FIGS. 2A and 2B  are views for schematically explaining operations in a first embodiment; 
           [0014]      FIG. 3  is a flow chart illustrating an AR display processing in the first embodiment; 
           [0015]      FIG. 4  is a schematic view illustrating one example of contents of a display-order management table; 
           [0016]      FIG. 5  is a flow chart illustrating an AR display processing in the second embodiment; and 
           [0017]      FIG. 6  is a flow chart illustrating an AR display processing in the third embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0018]    Hereinafter, there will be described embodiments by reference to the drawings. First, a first embodiment will be explained with reference to  FIGS. 1-3 .  FIG. 1  illustrates an electric configuration of a terminal  10  on which is installed an application  12   b  in one embodiment of a display program. In the present embodiment, the terminal  10  is a mobile device such as a smartphone. The terminal  10  includes a CPU  11 , a flash memory  12 , a RAM  13 , operation keys  15 , an LCD  16 , a touch panel  17 , a memory card interface (hereinafter referred to as “memory card I/F”)  18 , a voice input/output device  19 , a telephone network communication device  20 , an image taking device  21 , and a wireless communication device  23 . These devices are connected to each other, via a bus line′  24 . 
         [0019]    The CPU  11  controls the devices connected to the bus line  24 , according to fixed values, programs, and the like stored in the flash memory  12  and other similar storage devices. The flash memory  12  is a rewritable non-transitory memory. The flash memory  12  stores an operating system  12   a  and the application  12   b . Hereinafter, the operating system may be referred to as “OS”. Also, the CPU  11  which executes a program such as the application and the operating system may be hereinafter referred to simply as the name of the program. In the following explanation, for example, the term “application program” or “application” may mean the CPU  11  which executes the application. The OS  12   a  is basic, software for achieving standard functions of the terminal  10 . In the present embodiment, the OS  12   a  is an Android® (registered trademark of Google Inc) OS. 
         [0020]    The application  12   b  is an application provided by a vendor of the device and installed on the terminal  10  by a user, enabling the user to use various functions of the device from the terminal  10 . For example, the application  12   b  allows the user to directly use a printing function and a scanning function of the device from the terminal  10  not via a personal computer (hereinafter may be simply referred to as “PC”) or other similar devices. 
         [0021]    In the present embodiment, the application  12   b  detects a marker formed on the image taking object based on an image taken by the image taking device  21  and uses the AR technology to display an object for help information corresponding to the detected marker. That is, the application  12   b  displays the object for the help information that overlays a real-space image (which is an image in a real space) actually taken by the image taking device  21 . In the present embodiment, the image taking object is a multi-function peripheral (hereinafter referred to as “MFP”)  100 . The object displayed using the AR display is hereinafter referred to as “AR object”. In particular, the application  12   b  in the present embodiment can stop or freeze the AR object being displayed and keep the display even if the image taking device  21  cannot take an image of a marker corresponding to the AR object. Each of processings illustrated in the flow chart in  FIG. 3  which will be described below is executed by the CPU  11  according to the application  12   b.    
         [0022]    The flash memory  12  has an App storage area  12   c . The App storage area  12   c  is a storage area assigned to the application  12   b  for its use. The App storage area  12   c  stores an identification-information management table for managing available marker identification information. The App storage area  12   c  stores images for comparison in association with the marker identification information. Each of the images for comparison is used for specifying a corresponding marker based on the image taken by the image taking device  21 . The App storage area  12   e  also stores AR objects in association with the marker identification information. The RAM  13  is a rewritable transitory memory having a temporary area for temporarily storing data when the CPU  11  executes the application  12   b  and the like. 
         [0023]    The operation keys  15  are mechanical keys used for inputting instructions to the terminal  10  and are provided on a housing of the terminal  10 , for example. The LCD  16  is a liquid crystal display for displaying various screens. The touch panel  17  is superposed on the LCD  16 , and a user touches or approaches the touch panel  17  with an input object (e.g., a finger or a stylus) to input instructions to the terminal  10 . The memory card I/F  18  is an interface on which, a rewritable non-transitory memory card MC can be mounted. The memory card I/F  18  controls writing and reading of data on and from the memory card MC. The voice input/output device  19  is a voice input/output device including a microphone and a speaker. The telephone network communication device  20  is a circuit for voice conversation over a mobile phone network, not shown. 
         [0024]    The image taking device  21  is a camera capable of taking movie images and including an image pickup element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). In the present embodiment, the image taking device  21  is disposed on a back surface of the housing of the terminal  10 , i.e., on a surface thereof which is a back side from a surface thereof on which the LCD  16  is provided. 
         [0025]    The wireless communication device  23  is an interface for wireless communication over a wireless LAN. In the present embodiment, the wireless LAN communication device  23  is configured to perform wireless communication over a wireless LAN according to the IEEE802.11b/g/n standard. More specifically, the wireless communication performed by the wireless LAN communication device  23  is a wireless communication according to the Wi-Fi® (registered trademark of Wi-Fi Alliance.) standard (i.e., what is called Wi-Fi communication). In the present embodiment, the wireless communication device  23  is connected to the MFP  100  via an access point (hereinafter may be referred to as “AP”)  30  as a relay device. 
         [0026]    The AP  30  is a relay device for relaying the Wi-Fi communication. The AP  30  has a broadband router function and can be connected to Internet  800 . Thus, the terminal  10  can be communicably connected to various external devices such as a server  200  via the AP  30  and the Internet  800 . 
         [0027]    There will be next explained operations in the first embodiment with reference to  FIGS. 2A and 2B . As illustrated in  FIG. 2A , in the case where an image of a front face of the MFP  100  is taken by the image taking device  21  of the terminal  10 , the application  12   b  detects a sheet-supply tray  101  as a marker based on image matching between the image taken by the image taking device  21  and the comparison image stored in the App storage area  12   c . The application  12   b  controls the LCD  16  to display an image on which an AR object  81  for help information corresponding to the detected marker overlays a captured image  51  which is a real-space image taken by the image taking device  21  (in the example illustrated in  FIG. 2A , an image taken from a front side of the MFP  100 ). In other words, the application  12   b  controls the LCD  16  to display an image obtained by combining the AR object  81  and the captured image  51  with each other. In this specification, the captured image is an image displayed on the LCD  16  at a time among moving real-space images each taken by the image taking device  21  and displayed on the LCD  16  while changing every moment. 
         [0028]    When the AR object  81  is displayed, the application  12   b  displays a Pause button  61  at a lower right portion of the screen. The Pause button  61  is for instructing a pause or a stop of movement of the AR object  81  being displayed, that is, the Pause button  61  is for instructing stationarily keeping of the display. When a touch operation (what is called a tapping operation) is performed on the Pause button  61 , the application  12   b  freezes the display of the AR object  81 . In the case where the display of the AR object  81  is paused, even when detection of a marker corresponding to the AR object  81  has ceased, that is, even when the AD object  81  becomes out of the display region of the LCD  16 , the application  12   b  keeps displaying the AR object  81  without causing a stationary AR object  81  to disappear. 
         [0029]    Accordingly, the stationary AR object  81  is kept displayed without disappearing, even in the case where the Pause button  61  is operated in the state illustrated in  FIG. 2A , thereafter the MFP  100  falls outside an image taking area of the image taking device  21 , and consequently as illustrated in  FIG. 2B  an image taken by the image taking device  21  is a captured image  52  not including the marker corresponding to the AR object  81  being in a stationary displaying state (may be referred to as “stationary AR object  81 ”), for example. Thus, the user can view the AR object  81  without continuing taking the marker. 
         [0030]    When the display of the AR object  81  is paused, the application  12   b  displays a Resume button  62  instead of the Pause button  61 . The Resume button  62  is for, instructing a cancel of the stationary displaying state of the AR object  81 . When a touch operation is performed on the Resume button  62 , the application  12   b  cancels the stationary displaying state of the AR object  81 . As a result, the AR object  81  is hidden while the marker corresponding to the AR object  81  whose stationary displaying state has been canceled is not detected after the Resume button  62  is operated. 
         [0031]      FIG. 3  is a flow chart illustrating an AR display processing. This processing begins when the CPU  11  receives an operation for requesting a display of help information using the AR display during operation of the application  12   b . The CPU  11  at S 301  starts controlling the image taking device  21  to take an image in the real space and displays a captured image on the LCD  16 . With this processing, images in the real space (more specifically, moving images) taken by the image taking device  21  are sequentially displayed as the captured images on the LCD  16  until the present processing is finished. 
         [0032]    When a predetermined quitting operation is received by the CPU  11  (S 302 : Yes), this flow ends. When the predetermined quitting operation is not received by the CPU  11  (S 302 : Yes), the CPU  11  at S 303  determines whether a marker has been detected in the captured image or not based on image matching between the captured image and the comparison image. When the marker is not detected (S 303 : No), this flow returns to S 302 . 
         [0033]    When a marker is detected (S 303 : Yes), the CPU  11  at S 304  refers to the App storage area  12   c  to display an AR object corresponding to the detected marker. A display location of the AR object is determined based on display location information stored in the App storage area  12   c  in association with the marker and based on information including a location and an inclination of the marker in the captured image. Upon displaying the AR object at S 304 , the CPU  11  controls the LCD  16  to display a Pause button, e.g., the Pause button  61  illustrated in  FIG. 2A . 
         [0034]    The CPU  11  at S 305  determines whether the detection of the marker corresponding to the AR object displayed at S 304  is continued or not based on the image matching between the captured image and the comparison image. When the marker is not detected (S 305 : No), the CPU  11  at S 311  hides the AR object corresponding to the marker for which the detection has ceased, and this flow returns to S 302 . 
         [0035]    When the marker is continuously detected (S 305 : Yes), the CPU  11  at S 306  determines whether an operation on the Pause button displayed on the LCD  16  has been received or not. It is noted that when a positive decision is made at S 305 , the CPU  11  changes the display location of the AR object as needed according to changes in e.g., the location and inclination of the marker in the captured image. 
         [0036]    When the operation on the Pause button is not received by the CPU  11  (S 306 : No), this flow returns to S 305 . When the operation on the Pause button is received by the CPU  11  (S 306 : Yes), the CPU  11  at S 307  determines which area is an AR-object pausing area. The application  12   b  in the present embodiment is configured in advance to be capable of selecting one of (a) only the AR object on the entire screen (image) being displayed and (b) the entire screen being displayed, as the AR-object pausing area. The selected AR-object pausing area is stored into the App storage area  12   c , and the CPU  11  executes the determination at S 307  based on the contents stored in the App storage area  12   c . Thus, the CPU  11  can selectively use one of the different AR-object pausing areas based on the contents stored in the App storage area  12   c.    
         [0037]    When the CPU  11  determines that the AR-object pausing area is only the AR object (S 307 : AR OBJECT), the CPU  11  at S 308  pauses the AR object being displayed. That is, the display location of the AR object being displayed is fixed in the display region of the LCD  16  and is not changed depending upon information such as the location and inclination of the marker in the captured image. When the CPU  11  determines that the AR-object pausing area is the entire screen being displayed, (S 307 : ENTIRE SCREEN), the CPU  11  at S 312  pauses the screen being displayed, i.e., the screen containing the AR object. It is noted that upon pausing the AR object at S 308  or S 312 , the CPU  11  controls the LCD  16  to display the Resume button, e.g., the Resume button  62  illustrated in  FIG. 2B . 
         [0038]    After the processing at S 308  or S 312 , the CPU  11  at S 309  determines whether an operation on the Resume button displayed on the LCD  16  has been received or not. When the operation on the Resume button is not received by the CPU  11  (S 309 : No), the CPU  11  waits for the operation on the Resume button. 
         [0039]    It is noted that since the image taking of the image taking device  21  which is started at S 301  is being continued, when the AR-object pausing area is only the AR object, the CPU  11  displays the captured image taken by the image taking device  21 , on an area (as one example of a second area) on the LCD  16  which differs from an area (as one example of a first area) on which the AR object is displayed. Thus, the user can look for the next marker while viewing the captured image displayed on the LCD  16 . 
         [0040]    When the operation on the Resume button is received by the CPU  11  (S 309 : Yes), the CPU  11  at S 310  cancels the stationary displaying state of the AR object, and this flow goes to S 305 . With this processing, the stationary displaying state of the stationary AR object can be canceled as needed by the operation on the Resume button. 
         [0041]    When the stationary displaying state of the AR object is canceled at S 310 , and the detection of the marker corresponding to the AR object ceases, a negative decision is made at S 305 , and the CPU  11  executes the processing at S 311 . That is, when detection of the marker corresponding to the stationary AR object ceases after a cancel of its stationary displaying state, the marker is hidden. 
         [0042]    In the above-described first embodiment, in the case where the operation on the Pause button is received by the CPU  11  as a keeping instruction during display of the AR object, the display of the AR object is continued even after detection of the marker corresponding to the stationary AR object has ceased. This configuration allows the user to view the AR object without continuing taking an image of the marker. 
         [0043]    There will be next explained a second embodiment with reference to  FIGS. 4 and 5 . In this second embodiment, the CPU  11  considers a display order of a plurality of AR objects which is not considered in the first embodiment. It is noted that the same reference numerals as used in the first embodiment are used to designate the corresponding elements of this second embodiment, and an explanation of which is dispensed with. Hereinafter, a configuration specific to this second embodiment will be mainly explained. 
         [0044]      FIG. 4  is a schematic view illustrating one example of contents of a display-order management table  12   c   1 . The display-order management table  12   c   1  stored in the App storage area  12   c  is a table for managing a display order of a plurality of AR objects which should be displayed sequentially. In the display-order management table  12   c   1 , condition marker identification information  12   c   1   b  and an additional-display object flag  12   c   1   c  are associated with each set of detected marker identification information  12   c   1   a.    
         [0045]    A marker identified by the identification information  12   c   1   b , i.e., condition marker is a specific marker which is conditional to display of an AR object corresponding to a marker identified by the identification information  12   c   1  a in the case where the marker is detected. 
         [0046]    In the present embodiment, in the case where the marker identified by the identification information  12   c   1   a  has been detected, when an AR object corresponding to a condition marker identified by the identification information  12   c   1   b  corresponding to the identification information  12   c   1   a  is in the stationary displaying state, the CPU  11  displays an AR object corresponding to the detected marker. 
         [0047]    In the example illustrated in  FIG. 4 , for example, in the case where the identification information  12   c   1   a  is a marker B, a marker A is stored as the identification information  12   c   1   b  corresponding to the identification information  12   c   1   a . In this case, in the case where the marker B has been detected, when an AR object corresponding to the marker A is in the stationary displaying state, an AR object corresponding to the detected marker B is displayed. 
         [0048]    It is noted that in the case where there is no condition for displaying the AR object corresponding to the detected marker, “0” is stored as the identification information  12   c   1   b . In the example illustrated in  FIG. 4 , for example, in the case where the identification information  12   c   1   a  is the marker A, “0” is stored as the identification information  12   c   1   b  corresponding to the identification information  12   c   1   a . In this case, in the case where the marker A has been detected, the AR object corresponding to the marker A is displayed unconditionally. 
         [0049]    The additional-display object flag  12   c   1   c  is a flag indicating whether or not the AR object corresponding to the marker identified by the identification information  12   c   1   a  is an object to be additionally displayed. In the case where “1” is set for the additional-display object flag  12   c   1   c , this state of the additional-display object flag  12   c   1   c  indicates that the AR object corresponding to the marker identified by the identification information  12   c   1   a  is an object to be additionally displayed. In the case where “0” is set for the additional-display object flag  12   c   1   c , this state of the additional-display object flag  12   c   1   c  indicates that the AR object corresponding to the marker identified by the identification information  12   c   1   a  is not an object to be additionally displayed. 
         [0050]    In the case where the additional-display object flag  12   c   1   c  is 1, an AR object corresponding to a marker identified by the identification information  12   c   1   a  corresponding to the additional-display object flag  12   c   1   c  is displayed in addition to a stationary AR object, i.e., an AR object corresponding to a: marker identified by the identification information  12   c   1   b . In the case where the additional-display object flag  12   c   1   c  is 0, the AR object corresponding to the marker identified by the identification information  12   c   1   a  corresponding to the additional-display object flag  12   c   1   c  is displayed instead of the stationary AR object. 
         [0051]      FIG. 5  is a flow chart illustrating an AR display processing in the second embodiment. This processing is executed by the CPU  11  of the terminal  10  according to the application  12   b  in the second embodiment. This processing begins when the CPU  11  receives an operation for requesting a display of help information using the AR display dining operation of the application  12   b  as in the first embodiment. 
         [0052]    When a positive decision (Yes) is made at S 303  (S 303 : Yes), the CPU  11  at S 304  displays the AR object corresponding to the detected marker. In the present embodiment, the CPU  11  at S 304  displays the AR object corresponding to the detected marker regardless of the contents of the display-order management table  12   c   1 . 
         [0053]    When a positive decision (Yes) is made at S 306  (S 306 : Yes), the CPU  11  at S 308  pauses the AR object being displayed and at S 501  moves the stationary AR object to an edge portion of the screen of the LCD  16 , e.g., a lower left edge portion thereof. With this processing, the stationary AR object is kept displayed on a periphery portion of the LCD  16 , whereby an area on the LCD  16  which is located near the center of the LCD  16  can be used as an area for displaying a captured image taken by the image taking device  21 . This configuration can prevent the stationary AR object from deteriorating viewability of a main portion of the captured image, allowing the user to easily look for the next marker while viewing the captured image displayed on the LCD  16 . 
         [0054]    As in the processing at S 303 , the CPU  11  at S 502  determines whether a marker has been detected in the captured image or not. When no marker is detected (S 502 : No), this flow goes to S 309 . 
         [0055]    When a marker is detected (S 502 : Yes), the CPU  11  at S 503  determines whether the marker newly detected is identical to the marker corresponding to the stationary AR object or not. When these markers are identical to each other (S 503 : Yes), this flow goes to S 309 . In this case, the display of the stationary AR object is kept, and the AR object corresponding to the detected marker is not newly displayed. Accordingly, an overlap of displays of the same AR, object is avoided, preventing deterioration of viewability of the AR object. 
         [0056]    When the markers are not identical to each other (S 503 : No), the CPU  11  at S 504  refers to the display-order management table  12   c   1  to determine whether or not the marker newly detected is a marker to be displayed instead of the displayed marker. Specifically, a positive decision (Yes) is made at S 504  in the case where the marker identified by the identification information  12   c   1   b  corresponding to the newly-detected marker identification information  12   c   1   a  is the marker corresponding to the stationary AR object, and the additional-display object flag  12   c   1   c  corresponding to the identification information  12   c   1  a is 0. In the other cases, a negative decision (No) is made at S 504 . 
         [0057]    When a positive decision (Yes) is made at S 504  (S 504 : Yes), the CPU  11  at S 505  displays an AR object corresponding to the newly detected marker at a display location determined as in the processing at S 304 . The CPU  11  at S 506  hides the stationary AR object, and this flow returns to S 305 . In this case, the AR object corresponding to the newly detected marker is displayed on the LCD  16  instead of the stationary AR object. 
         [0058]    When a negative decision is made at S 504  (S 504 : No), the CPU  11  at S 507  refers to the display-order management table  12   c   1  to determine whether the newly detected marker is a marker to be added. Specifically, a positive decision is made at S 507  in the case where the marker identified by the identification information  12   c   1   b  corresponding to the newly-detected marker identification information  12   c   1   a  is the marker corresponding to the stationary AR object, and the additional-display object flag  12   c   1   c  corresponding to the identification information  12   c   1   a  is 1. In the other cases, a negative decision (No) is made at S 507 . 
         [0059]    When a positive decision is made at S 507  (S 507 : Yes), the CPU  11  at S 508  additionally displays the AR object corresponding to the newly detected marker. That is, the CPU  11  displays the AR object corresponding to the newly detected marker without hiding the stationary AR object. It is noted that a display location of the AR object corresponding to the newly detected marker is determined as in the processing at S 304 . 
         [0060]    When a negative decision (No) is made at S 507 , that is, when the marker corresponding to the stationary AR object is not a condition marker for the newly detected marker (S 507 : No), this flow goes to S 502 . In this case, the display of the stationary AR object is kept, and the AR object corresponding to the newly detected marker is not displayed. 
         [0061]    In the above-described second embodiment, the AR objects can be displayed in the display order according to the contents stored in the display-order management table  12   c   1 . Thus, in the case where a series of help information are constituted by a plurality of AR objects, the series of the help information can be displayed in the right order. 
         [0062]    The AR object corresponding to the newly detected marker can be displayed instead of the stationary AR object, thereby preventing deterioration of viewability of the AR object corresponding to the newly detected marker. 
         [0063]    The CPU  11  can not only display the AR object corresponding to the newly detected marker instead of the stationary AR object but also additionally display the AR object corresponding to the newly detected marker, allowing the user to easily understand a series of help information. 
         [0064]    There will be next explained a third embodiment with reference to  FIG. 6 . In this third embodiment, the CPU  11  considers a case where a plurality of markers are detected at the same time, which case is not considered in the first embodiment. It is noted that the same reference numerals as used in the first embodiment are used to designate the corresponding elements of this third embodiment, and an explanation of which is dispensed with. Hereinafter, a configuration specific to this third embodiment will be mainly explained. 
         [0065]      FIG. 6  is a flow chart illustrating an AR display processing in the third embodiment. This processing is executed by the CPU  11  of the terminal  10  according to the application  12   b  in the third embodiment. This processing begins when the CPU  11  receives an operation for requesting a display of help information using the AR display during operation of the application  12   b  as in the first embodiment. 
         [0066]    When a positive decision (Yes) is made at S 303  (S 303 : Yes), the CPU  11  at S 304  displays the AR object corresponding to the detected marker. In the present embodiment, in the case where a plurality of markers have been detected, the CPU  11  displays AR objects respectively corresponding to the detected markers. 
         [0067]    When a positive decision (Yes) is made at S 306  (S 306 : Yes), the CPU  11  at S 601  determines whether a plurality of AR objects are being displayed or not. When a plurality of AR objects are not being displayed, that is, one AR object is being displayed (S 601 : No), the CPU  11  at S 308  pauses the display of the one AR object, and this flow goes to S 309 . 
         [0068]    When a plurality of AR objects are being displayed (S 601 : Yes), the CPU  11  waits for selection of one of the AR object being displayed (S 602 : No). In the present embodiment, in the case where a plurality of AR objects are being displayed, the CPU  11  displays a screen for selecting an AR object, upon receiving an operation on the Pause button. When a selecting operation is performed on the screen, the CPU  11  accepts selection for the one AR object. 
         [0069]    When the CPU  11  accepts the selection for the one AR object (S 602 : Yes), the CPU  11  at S 603  pauses the selected AR object, and this flow goes to S 309 . 
         [0070]    In the above-described third embodiment, in the case where a plurality of AR objects being displayed when the operation on the Pause button is performed, one of the AR objects can be selected as an object to be paused, thereby pausing only the AR object to be paused. This configuration allows the user to easily view necessary information. 
         [0071]    In the above-described embodiments, the application  12   b  is one example of the display program. The terminal  10  is one example of a display device. The CPU  11  is one example of a computer. The LCD  16  is one example of a display. The image taking device  21  is one example of an image taking device. The flash memory  12  is one example of a storage. The identification information  12   c   1   b  is one example of first information. The additional-display object flag  12   c   1   e  is one example of second information. The AR object  81  is one example of a content associated with a marker. 
         [0072]    While the embodiments have been described above, it is to be understood that the disclosure is not limited to the details of the illustrated embodiments, but may be embodied with various changes and modifications, which may occur to those skilled in the art, without departing from the spirit and scope of the disclosure. 
         [0073]    For example, while the terminal  10  such as a smartphone is used as the display device on which the application  12   b  is installed in the above-described embodiments, various devices may be used as the display device as long as each of the devices has a structure equivalent to the image taking device  21 . For example, a device such as a tablet computer or a laptop computer has the structure equivalent to the image taking device  21 , the device may be employed as the display device on which the application  12   b  is installed. Also, a digital camera may be employed as the display device on which the application  12   b  is installed. While the OS  12   a  of the terminal  10  is the Android OS in the above-described embodiments, another OS may be employed. 
         [0074]    In the above-described embodiments, the CPU  11  of the terminal  10  detects the marker on the captured image. That is, the CPU  11  is one example of a detector in the above-described embodiments. Instead of this configuration, the terminal  10  may be configured to transmit the captured image to the server  200 , and the server  200  may detect the marker on the captured image. In this modification, the server  200  is one example of the detector. Also, the AR objects are stored in the App storage area  12   c  in the above-described embodiments. Instead of this configuration, the AR objects may be stored in the server  200 , and at least one AR object may be retrieved from the server  200  according to the detected marker. 
         [0075]    In the above-described first embodiment, when the operation on the Pause button is performed, at least one of the AR objects being displayed and the entire screen containing the AR object is paused, the present disclosure is not limited to this configuration. For example, the AR object may be moved on the display region as long as at least one of the AR objects is being displayed on the display region of the LCD  16 . The AR object may be moved according to the location of the marker on the captured image. For example, by displaying the AR object at any position on the display region of the LCD  16  even if the marker falls outside the captured image, the AR object can be continuously displayed on the LCD  16 . Since the AR object is continuously displayed on the LCD  16 , the user can continuously view the AR object. 
         [0076]    While the AR-object pausing area is selected to one of only the AR object and the entire screen being displayed in the above-described first embodiment, only one of them may be employed. Also, while the AR-object pausing area is selected based on the contents stored in the App storage area  12   c , the AR-object pausing area may be selected after the operation on the Pause button. 
         [0077]    In the above-described second embodiment, when the operation on the Pause button is performed, the stationary AR object is moved to an edge portion of the screen. However, in the case where the AR-object pausing area is the entire screen, the entire screen containing the stationary AR object may be reduced in size and displayed on an edge portion of the screen. 
         [0078]    In the above-described second embodiment, the detected marker identification information  12   c   1   a  and the condition marker identification information  12   c   1   b  are associated with each other in the display-order management table  12   c   1  to determine the display order of the AR objects. However, the display order of the AR objects may be determined in another manner. For example, information about numeric values for specifying the display order may be associated with available markers. 
         [0079]    In the above-described third embodiment, in the case where the plurality of AR objects are being displayed when the operation on the Pause button is performed, the user selects one of the AR objects. Instead of this configuration, information capable of specifying an AR object to be selected as an object to be paused, among AR objects respectively corresponding to markers which can be detected at the same time may be stored in the App storage area  12   c  in advance, and the CPU  11  may select one AR object based on the contents stored in the App storage area  12   c . Examples of the information capable of specifying the AR object to be selected as the object to be paused include identification information for the marker previously detected. Also, after all the AR objects are paused, unnecessary AR objects may be deleted by a predetermined operation. 
         [0080]    The number of selectable AR objects is not limited to one, and a plurality of AR objects may be selected. In this modification, for example, an upper limit value for selection is set, and any number of AR objects may be selected as objects to be paused as long as the number is less than or equal to the upper limit value. 
         [0081]    While the marker is detected based on image matching between the image taken by the image taking device  21  and the comparison image stored in the App storage area  12   c  in the above-described embodiments, marks such as two-dimensional codes and text information attached to the MFP  100  may be used each as the marker. In this modification, in the case where the two-dimensional code is taken by the image taking device  21 , the CPU  11  determines that the marker is detected, and an AR object corresponding to information stored in the two-dimensional code is displayed, for example. 
         [0082]    While the CPU  11  executes the processings illustrated in  FIGS. 3 ,  5 , and  6  in the above-described embodiments, a plurality of CPUs may cooperate to execute the processings. One or more ICs such as ASICs may execute the processings alone or in combination. Also, the CPU  11  and the IC such as the ASIC may cooperate to execute the processings. Some of the processings illustrated in  FIGS. 3 ,  5 , and  6  may be omitted or changed without departing from the spirit and scope of the disclosure. The features in the above-described embodiments and the above-described modifications may be embodied as needed in combination.