Abstract:
A guiding method includes obtaining data of a first image, detecting with a computer reference image data corresponding to a reference object in the data of the first image, calculating with the computer a first condition based on an appearance of the reference object in the first image, the first condition indicating an operational condition of an imaging apparatus when first image was captured, and for a second image to be captured, outputting guide information that indicates how to adjust the first condition to match a reference condition, the reference condition corresponds to an appearance of the reference object in a reference image captured under the reference condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. application Ser. No. 14/518,850, filed Oct. 20, 2014, which is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2013-221644, filed on Oct. 24, 2013, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     The techniques disclosed in the present embodiments are related to carry out guiding when taking an image subject to observation. 
     BACKGROUND 
     In order to facilitate maintenance and management services, there is a display apparatus that superimposes a plurality of image data items to generate one still image (for example, Japanese Laid-open Patent Publication No. 2001-14316). The display apparatus evaluates an absolute position of each image and relative positions between the plurality of image data items while generating a still image so as to correspond the position of each other. After a video camera is directed in a predetermined direction, an automobile having the video camera mounted therein runs along an object, thereby collecting a plurality of image data items. In maintenance and management services for a building, a road, a bridge, and the like, the display apparatus is intended to manage structures, such as a bridge through a road, a slope, and the like, as one still image. 
     SUMMARY 
     According to an aspect of the invention, a guiding method includes obtaining data of a first image, detecting with a computer reference image data corresponding to a reference object in the data of the first image, calculating with the computer a first condition based on an appearance of the reference object in the first image, the first condition indicating an operational condition of an imaging apparatus when first image was captured, and for a second image to be captured, outputting guide information that indicates how to adjust the first condition to match a reference condition, the reference condition corresponds to an appearance of the reference object in a reference image captured under the reference condition. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A and 1B  illustrate two images of a same observation object taken at different clock times; 
         FIG. 2  is a schematic diagram of a synthesized image; 
         FIG. 3  illustrates relationship between a camera coordinate system and a marker coordinate system; 
         FIG. 4  illustrates an example of an AR object E in the camera coordinate system and the marker coordinate system; 
         FIG. 5  illustrates a transformation matrix M from the marker coordinate system to the camera coordinate system and a rotation matrix R in the transformation matrix M; 
         FIG. 6  illustrates rotation matrices R 1 , R 2 , and R 3 ; 
         FIGS. 7A and 7B  illustrate images taken in different imaging conditions; 
         FIG. 8  is a system configuration diagram according to a first embodiment; 
         FIG. 9  is a functional block diagram of an information processing apparatus according to the first embodiment; 
         FIG. 10  illustrates a template information table; 
         FIG. 11  illustrates a content information table; 
         FIG. 12  illustrates an imaging condition information table; 
         FIG. 13  illustrates a storage image table; 
         FIG. 14  is a functional block diagram of a management apparatus; 
         FIG. 15  illustrates a flowchart of guiding process according to the first embodiment; 
         FIG. 16  is an example of a synthesized image including guide display; 
         FIGS. 17A and 17B  illustrate guide display according to a second embodiment; 
         FIG. 18  is a functional block diagram of an information processing apparatus according to the second embodiment; 
         FIG. 19  illustrates an imaging condition information table in the second embodiment; 
         FIG. 20  illustrates a flowchart of guiding process according to the second embodiment; 
         FIG. 21  illustrates an imaging condition information table in a first modification; 
         FIG. 22  is a schematic diagram of map data where movement loci of a user are mapped; 
         FIG. 23  is a hardware configuration example of the information processing apparatus in each embodiment; 
         FIG. 24  illustrates a configuration example of a program that runs in a computer  1000 ; and 
         FIG. 25  is a hardware configuration example of a management apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In an inspection service and the like, a plurality of images of an object taken at different clock times are compared. In this case, it is preferred that the plurality of images are taken from an approximately identical position for accurate and easy comparison. 
     With that, for example, an approach of physically fixing a camera is considered in order to take a plurality of images from an approximately identical position. However, when there are a plurality of imaging objects, a camera has to be provided for each imaging object. 
     In addition, when the display apparatus disclosed in Japanese Laid-open Patent Publication No. 2001-14316 synthesizes a still image, a plurality of image data items to be source of the synthesis is collected by directing a video camera in a predetermined direction by an operator. However, since the direction of the video camera results from judgment of the operator, the synthesized still image does not have to be a still image suitable for the comparison. 
     With that, in order to observe change with time in a specific object, it is an object of the technique disclosed in the present embodiments to take an image of the object in a specific imaging condition. 
     Descriptions are given below to detailed embodiments of the present disclosure. It is possible to appropriately combine each embodiment below without contradicting the contents of process. Each embodiment is described below based on the drawings. 
     First of all, descriptions are given to an activity to observe change with time in a specific object in an inspection service and maintenance and management services. Hereinafter, the object to be observed is referred to as an observation object.  FIGS. 1A and 1B  illustrate two images of a same observation object taken at different clock times. 
       FIGS. 1A and 1B  are images in which a crack in piping, which is a same observation object, is taken while imaging conditions for each of the two images are different. The imaging conditions in the present embodiment are an imaging position and an imaging direction. The imaging position is a position of a camera. The imaging direction is a direction of an optical axis of the camera when taking an image. 
     Specifically, an image  100  in  FIG. 1A  includes a crack  104  present in piping  102 , and an image  106  in  FIG. 1B  includes a crack  110  present in piping  108 . When it is assumed that the image  106  is taken after the image  100 , it is difficult for the operator that carries out observation to intrinsically understand whether the size and the position of the crack  110  change from the state of the crack  104 . In practice, the piping  102  and the piping  108  are an identical object, and the crack  104  and the crack  110  are also an identical object. 
     If the image  106  is an image that is taken in imaging conditions similar to the imaging conditions when the image  100  is taken, it is possible that an operator confirms whether there is a change in the crack  104  only by visually comparing the image  100  with the image  106 . Although it is also considered to transform the image  100  and the image  106  to easily compared images by image processing, an image processing technique has to be introduced. 
     Meanwhile, currently, there are increasing cases of introducing an augmented reality (AR) technique for the purpose of efficiency of various services, such as an inspection service and maintenance and management services. The AR technique virtually sets a three dimensional virtual space corresponding to a real space and places model data of a three dimensional object in the virtual space. Then, the AR technique superimposes the virtual space where the model data is placed on a taken image taken by a camera, thereby generating a synthesized image where model data viewed from a certain viewpoint (camera position) is superposition displayed on the taken image in the real space. That is, it is possible that a user browsing a synthesized image recognizes as if there is model data that does not exist in the real space is present in the real space through a display on which the synthesized image is displayed. 
     In such a manner, according to the AR technique, information gathered by human perception (such as vision) extends. For example, when the model data indicates description information regarding an object present in the real space, instruction information on contents of the activity, attention calling information, and the like, it is possible for the user to understand the information. 
       FIG. 2  is a schematic diagram of a synthesized image. A synthesized image  200  includes piping  202  and a crack  204  that are present in the real space as well as an AR object E that is not present in the real space. The piping  202  and the crack  204  correspond to the piping  102  and the crack  104  in  FIG. 1A , respectively. The AR object E is three dimensional model data that is placed in the virtual space. The synthesized image  200  also includes a marker M present in the real space. The relationship between the marker M and the AR technique is described later. 
     When the AR technique is applied to an inspection service, an operator of the inspection service browses the synthesized image  200 , thereby allowing understanding that there is the crack  204  in a specific position in the piping  202 . That is, compared with a case that the operator directly views the real space, it is possible for the operator to easily understand the presence of the crack  204 . In such a manner, the AR technique is introduced as a tool for sharing an informative matter and activity contents, thereby promoting efficiency of an inspection activity in a facility and the like. 
     Next, the marker M in  FIG. 2  is described. In order to display the AR object E in the position of the crack  204  in  FIG. 2 , the positional relationship between the real space where the crack  204  is present and the virtual space where the AR object E is placed has to be associated. The marker M is used to associate the positional relationship between the real space and the virtual space. 
     The virtual space where the AR object E is placed is a three dimensional space using the marker M as a reference. That is, the placement position and the placement posture relative to the marker are set in the AR object. Meanwhile, since the marker M also exists in the real space, when the marker M is recognized from the taken image in which the real space is taken, the virtual space and the real space are associated via the marker M. In the AR technique, an object to be a reference for a virtual space, such as the marker M, is referred to as a reference object. 
     That is, while an AR object is placed in the virtual space, the positional relationship between the camera and the reference object in the real space is obtained based on appearance (picture) of the reference object included in the taken image taken by the camera. Then, positional relationship between the coordinates of respective points of the camera and the AR object in the three dimensional virtual space corresponding to the real space is obtained by the coordinates in the virtual space using the reference object present in the real space as a reference and the positional relationship between the camera and the reference object in the real space. Based on the positional relationship, the picture of the AR object obtained when the reference object is imaged by the camera in the virtual space is determined. Then, the picture of the AR object is displayed by superposition on the taken image. 
     Here, detailed descriptions are given to a method of calculating a picture of an AR object in order to generate a synthesized image.  FIG. 3  illustrates relationship between the camera coordinate system and the marker coordinate system. The marker M exemplified in  FIG. 3  is in a square shape and is established in size in advance (for example, the length of each side is 5 cm and the like). Although the marker M illustrated in  FIG. 3  is in a square shape, another object in a shape capable of distinguishing the relative positions and the direction from the camera may also be used for the reference object based on a picture obtained by taking from any viewpoint of a plurality of viewpoints. 
     The camera coordinate system is configured three dimensionally with (Xc, Yc, Zc), and for example, a focus of the camera is assumed to be the origin (origin Oc). For example, an Xc-Yc plane in the camera coordinate system is a plane parallel to an imaging device plane of the camera, and a Zc axis is an axis vertical to the imaging device plane. 
     The marker coordinate system is configured three dimensionally with (Xm, Ym, Zm), and for example, a center of the marker M is assumed to be the origin (origin Om). For example, an Xm-Ym plane in the marker coordinate system is a plane parallel to the marker M, and a Zm axis is vertical to a plane of the marker M. The origin Om is represented as coordinates V 1   c  (X 1   c , Y 1   c , Z 1   c ) in the camera coordinate system. A space configured in the marker coordinate system is the virtual space. 
     A rotation angle of the marker coordinate system (Xm, Ym, Zm) relative to the camera coordinate system (Xc, Yc, Zc) is represented as rotational coordinates G 1   c  (P 1   c , Q 1   c , R 1   c ). P 1   c  is a rotation angle about the Xc axis, Q 1   c  is a rotation angle about the Yc axis, and R 1   c  is a rotation angle about the Zc axis. Since the marker coordinate system exemplified in  FIG. 3  rotates only about the Ym axis, P 1   c  and R 1   c  are 0. The respective rotation angles are calculated based on that as what sort of picture a reference object having a known shape is imaged in the taken image subject to the process. 
       FIG. 4  illustrates an example of an AR object E in the camera coordinate system and the marker coordinate system. The AR object E illustrated in  FIG. 4  is an object in a balloon shape and includes text data of “there is a crack!” in a balloon. 
     A black dot at a tip of the balloon of the AR object E indicates a reference point of the AR object E. The coordinates of the reference point in the marker coordinate system is assumed to be V 2   m  (X 2   m , Y 2   m , Z 2   m ). Further, the direction of the AR object E is established by the rotational coordinates G 2   m  (P 2   m , Q 2   m , R 2   m ), and the size of the AR object E is established by a magnification D (Jx, Jy, Jz). The rotational coordinates G 2   m  of the AR object E indicates that to what extent the AR object is placed in a state of being rotated relative to the marker coordinate system. For example, when G 2   m  is (0, 0, 0), the AR object is AR displayed parallel to the marker M. 
     The coordinates of each point that configures the AR object E are coordinates obtained by adjusting coordinates of respective points defined in definition data (AR template), which is a prototype of the AR object E, based on the coordinates V 2   m , the rotational coordinates G 2   m , and the magnification D of the reference point. 
     In the AR template, coordinates of each point is defined as the coordinates of the reference point to be (0, 0, 0). Therefore, as the reference point V 2   m  of the AR object E employing the AR template is set, the coordinates of each point that configures the AR template are moved in parallel based on the coordinates V 2   m.    
     Further, each coordinate included in the AR template is rotated based on the set rotational coordinates G 2   m  and is zoomed in or out at the magnification D. That is, the AR object E in  FIG. 4  illustrates a state of each point defined in the AR template is configured based on points adjusted based on the coordinates V 2   m , the rotational coordinates G 2   m , and the magnification D of the reference point. 
     In addition, the AR object E may also be generated by initially generating an AR object E′, which is a set of points adjusted based on the coordinates V 2   m  and the magnification D of the reference point, and after that rotating each axis of the AR object E′ in accordance with the rotational coordinates G 2   m.    
     Next, as the AR object E is placed in the marker coordinate system, the coordinates of each point of the AR object E are transformed from the marker coordinate system to the camera coordinate system. Further, in order to project the AR object E on the taken image, transformation from the camera coordinate system to the screen coordinate system is carried out. That is, a picture for superposition display of the AR object E on the taken image is generated. 
     Descriptions are given below to process to transform a coordinate system. Firstly, model/view transformation to transform the marker coordinate system to the camera coordinate system is described. Regarding each point included in the AR object E, the coordinates in the marker coordinate system are subject to coordinate transformation based on the coordinates V 1   c  in the camera coordinate system of the origin Om of the marker and the rotational coordinates G 1   c  in the marker coordinate system relative to the camera coordinate system, thereby calculating coordinates in the camera coordinate system. 
     For example, by carrying out the model/view transformation to the reference point V 2   m  of the AR object E, to which point in the camera coordinate system the reference point prescribed in the marker coordinate system corresponds is obtained. In practice, the coordinates V 2   c  in the camera coordinate system corresponding to V 2   m  is obtained. 
       FIG. 5  illustrates the transformation matrix M from the marker coordinate system to the camera coordinate system and the rotation matrix R in the transformation matrix M. The transformation matrix M is a 4×4 matrix. By a product of the transformation matrix M and a column vector (Xm, Ym, Zm, 1) regarding the coordinates Vm in the marker coordinate system, a column vector (Xc, Yc, Zc, 1) regarding the corresponding coordinates Vc in the camera coordinate system is obtained. 
     In other words, by carrying out matrix calculation by substituting point coordinates in the marker coordinate system subject to model/view transformation to the column vector (Xm, Ym, Zm, 1), a column vector (Xc, Yc, Zc, 1) including the point coordinates in the camera coordinate system is obtained. 
     A submatrix (rotation matrix R) of 1st through 3rd rows and 1st through 3rd columns of the transformation matrix M acts on the coordinates in the marker coordinate system, thereby carrying out a rotation operation to match the direction of the marker coordinate system and the direction of the camera coordinate system. A submatrix of 1st through 3rd rows and 4th columns of the transformation matrix M acts, thereby carrying out a translation operation to match the direction of the marker coordinate system and the position of the camera coordinate system. 
       FIG. 6  illustrates rotation matrices R 1 , R 2 , and R 3 . The rotation matrix R illustrated in  FIG. 5  is calculated by a product (R 1 ·R 2 ·R 3 ) of the rotation matrices R 1 , R 2 , and R 3 . The rotation matrix R 1  indicates rotation of the Xm axis relative to the Xc axis. The rotation matrix R 2  indicates rotation of the Ym axis relative to the Yc axis. The rotation matrix R 3  indicates rotation of the Zm axis relative to the Zc axis. 
     The rotation matrices R 1 , R 2 , and R 3  are generated based on the picture of the reference object in the taken image. That is, the rotation angles P 1   c , Q 1   c , and R 1   c  are calculated as described above based on that as what sort of picture a reference object having a known shape is imaged in the taken image subject to the process. Then, based on the rotation angles P 1   c , Q 1   c , and R 1   c , the respective rotation matrices R 1 , R 2 , and R 3  are generated. 
     As just described, the coordinates (Xm, Ym, Zm) in the marker coordinate system of each point that configures the AR object E are transformed to the coordinates (Xc, Yc, Zc) in the camera coordinate system by model/view transformation based on the transformation matrix M. The coordinates (Xc, Yc, Zc) obtained by the model/view transformation indicate a relative position from the camera when a camera is assumed to be virtually present in a virtual space where the AR object E is present. 
     Next, the coordinates in the camera coordinate system of each point of the AR object E are transformed to a screen coordinate system. Transformation of a camera coordinate system to a screen coordinate system is referred to as perspective transformation. A screen coordinate system is configured two dimensionally with (Xs, Ys). The screen coordinate system (Xs, Ys) has, for example, a center of a taken image obtained by imaging process of a camera as the origin (origin Os). Based on coordinates in the screen coordinate system of each point obtained by the perspective transformation, a picture for superposition display of the AR object E on the taken image is generated. 
     The perspective transformation is carried out based on, for example, a focal length f of the camera. The Xs coordinate of the coordinates in the screen coordinate system corresponding to the coordinates (Xc, Yc, Zc) in the camera coordinate system is obtained by the following formula 1. The Ys coordinate of the coordinates in the screen coordinate system corresponding to the coordinates (Xc, Yc, Zc) in the camera coordinate system is obtained by the following formula 2.
 
 Xs=f·Xc/Zc   (Formula 1)
 
 Ys=f·Yc/Zc   (Formula 2)
 
     Based on the coordinates obtained by the perspective transformation, a picture of the AR object E is generated. The AR object E is generated by mapping a texture on a plane obtained by interpolating a plurality of points that configure the AR object E. In the AR template to be a source of the AR object E, which point is to be interpolated to form a plane and which texture is to be mapped on which plane are defined. 
     The coordinates in the taken image corresponding to the coordinates in the marker coordinate system are calculated by the model/view transformation and the perspective transformation to utilize the coordinates, thereby generating a picture of the AR object E in accordance with the viewpoint of the camera. The picture of the AR object E thus generated is called as a projection image of the AR object E. The projection image of the AR object E is synthesized to the taken image, thereby generating a synthesized image. Then, the synthesized image extends visual information provided to a user. 
     In addition, in another embodiment, a projection image of the AR object E is displayed on a transmissive display. In this embodiment as well, a picture in the real space that a user obtains by transmission through a display matches the projection image of the AR object E, so that the visual information provided to the user extends. 
     Here, the inventor paid attention to capability of estimating the imaging position and the imaging direction relative to the reference object by utilizing the picture of the reference object in the image. Then, the inventor found that it is possible to take a plurality of images subject to observation in a specific imaging condition by utilizing the AR technique as long as the positional relationship between the reference object and the observation object is unchanged. 
     With that, in the technique according to the present embodiment, guidance is performed in an embodiment capable of understanding a difference between an imaging position and an imaging direction (imaging conditions) that are specified in advance and an imaging position and an imaging direction (imaging conditions) of an input image. Therefore, the technique according to the present embodiment leads a user to be guided to the imaging position and the imaging direction that are specified in advance. The imaging position and the imaging direction relative the reference object may be considered as an imaging position and an imaging direction relative to the observation object. 
       FIGS. 7A and 7B  illustrate images taken in different imaging conditions.  FIGS. 7A and 7B  are taken images in which the real space is taken similar to  FIGS. 1A and 1B . It is to be noted that, different from  FIGS. 1A and 1B , a marker is attached to the piping to apply the AR technique. 
     Further, in the present embodiment, images taken at a fixed frame interval by a camera is referred to as taken images. While the taken images are temporarily stored in a buffer of an information processing apparatus (described later), an image to observe change with time in the observation object is stored separately in a memory as a storage image. 
     An image  300  in  FIG. 7A  is an image to be a reference when observing change with time in a crack  304 , which is an observation object. Accordingly, an operator compares with another image to confirm whether the crack  304  in the image  300  extends or not. Here, as described above, it is preferred that the other image is taken in imaging conditions similar to the image  300 . The image  300  includes piping  302 , the crack  304 , and a marker  306 . 
     Next, although an image  308  in  FIG. 7B  is an image including a crack  312 , which is an observation object, the image  308  is not appropriate as an image to be compared with the image  300 . This is because the picture of the marker  306  in the image  300  and the picture of a marker  314  in the image  308  are present in different size and in different positions, so that the image  308  is supposed to be taken in an imaging position different from the image  300 . When the imaging direction is also different, the shape of the picture of the marker  306  turns out to be different from the shape of the picture of the marker  314  as well. 
     With that, the technique disclosed in the present embodiment leads an operator to take an image in imaging conditions matching the imaging conditions of the image  300  to be the reference. It is to be noted that the “matching” in the present embodiment includes not only perfect matching but also approximate matching. That is, the matching may be to the extent that a person observing the change with time in the observation object is capable of recognizing the plurality of images to be compared as images taken in the identical imaging conditions. 
     First Embodiment 
     Firstly, descriptions are given to detailed process and configuration of an information processing apparatus and the like according to the first embodiment.  FIG. 8  is a system configuration diagram according to the first embodiment. The system includes a communication terminal  1 - 1 , a communication terminal  1 - 2 , and a management apparatus  2 . Hereinafter, the communication terminal  1 - 1  and the communication terminal  1 - 2  are collectively referred to as an information processing apparatus  1 . 
     The information processing apparatus  1  is a computer, such as a tablet PC and a smartphone, having a camera, for example. For example, the information processing apparatus  1  is held by an operator that carries out an inspection activity. The information processing apparatus  1  generates a synthesized image and also performs guidance of imaging conditions. Further, the information processing apparatus  1  communicates with the management apparatus  2  via the network N. The management apparatus  2  is, for example, a server computer, and manages a plurality of information processing apparatuses  1 . The network N is, for example, the internet. 
     Firstly, when recognizing a reference object in the taken image, the information processing apparatus  1  sends identification information (for example, marker ID) to identify the recognized reference object to the management apparatus  2 . When receiving the identification information from the information processing apparatus  1 , the management apparatus  2  provides imaging condition information corresponding to the identification information to the information processing apparatus  1 . The imaging condition information is information indicating the imaging position and the imaging direction to be the reference. 
     The information processing apparatus  1  estimates imaging conditions based on the picture of the reference object recognized from the taken image and also performs guidance so as to allow the operator to understand a difference between the estimated imaging conditions and the imaging conditions to be the reference. 
     For example, the information processing apparatus  1  obtains a difference between the estimated imaging position and the imaging position to be the reference and displays an arrow prompting movement in a direction filling the difference as a guide on the taken image. When the operator alters the imaging position in accordance with the guide display, thereby approximately matching the new imaging position and the imaging position to be the reference, the information processing apparatus  1  obtains a taken image at the time of approximate matching as a storage image. In addition, when matching approximately, the information processing apparatus  1  instructs the operator to carry out an imaging determination input in the current imaging position. For example, the information processing apparatus  1  instructs pressing of a shutter button. 
     Then, the information processing apparatus  1  sends the obtained storage image and time and date of the obtainment to the management apparatus  2 . The management apparatus  2  stores them together with the storage image received from the information processing apparatus  1 . 
     In addition, in the present embodiment, the management apparatus  2  provides, as well as the imaging condition information, information desired to generate the synthesized image (content information and template information) to the information processing apparatus  1 . Details are described later. The information processing apparatus  1  generates a synthesized image in the method described above and also displays the image on the display. Upon this, it is possible that the operator browses an AR content (for example, a projection image on which the object E in  FIG. 4  is projected) to understand the position of the presence of a crack. In addition, an AR content including a message indicating contents of an activity of “image the crack” may also be displayed further. 
     The timing to provide the imaging condition information, the content information, the template information, and the like from the management apparatus  2  to the information processing apparatus  1  is not limited to after recognition of the reference object in the information processing apparatus  1 . For example, the imaging condition information and the like related to a plurality of reference objects may also be provided from the management apparatus  2  to the information processing apparatus  1  before recognition of the reference objects. 
     Next, descriptions are given to functional configuration of the information processing apparatus  1 .  FIG. 9  is a functional block diagram of an information processing apparatus according to the first embodiment. The information processing apparatus  1  includes a communication unit  11 , an imaging unit  12 , a display unit  13 , a storage unit  14 , and a control unit  15 . 
     The communication unit  11  carries out communication with another computer. For example, the communication unit  11  receives the imaging condition information, the content information, and the template information from the management apparatus  2 . After a storage image is stored, the communication unit  11  also sends the storage image to the management apparatus  2 . 
     The imaging unit  12  takes an image at a fixed frame interval. The camera is equivalent to the imaging unit  12 . Then, the imaging unit  12  inputs a taken image to the control unit  15 . The display unit  13  displays an image. For example, the display unit  13  displays a synthesized image including a projection image of an AR object and a synthesized image including guide display. 
     The storage unit  14  stores various types of information under the control by the control unit  15 . The storage unit  14  stores the content information, the template information, the imaging condition information, and the like. Further, the storage unit  14  stores a storage image under the control by the control unit  15 . 
     The control unit  15  controls various types of process of the entire information processing apparatus  1 . The control unit  15  includes a recognition unit  16 , a guide performing unit  17 , and an image generation unit  18 . The recognition unit  16  recognizes the reference object from the input image. In the present embodiment, the recognition unit  16  recognizes a marker. For example, the recognition unit  16  recognizes the marker using a recognition template in which the shape of marker is given to carry out template matching. 
     Further, the recognition unit  16  obtains the identification information to identify a reference object. For example, a marker ID is obtained. Reading of the marker ID is carried out based on, for example, brightness information within an image region that corresponds to the marker. For example, when the marker is in a quadrilateral shape, the recognition unit  16  decides whether each region that is obtained by dividing the quadrilateral image region recognized as the marker, where a region having brightness of not less than a predetermined value is “1” and a region having brightness of less than the predetermined value is “0”, is “1” or “0” in a predetermined order to set the column of the information obtained by the decision as the marker ID. 
     In addition, for example, placement of the region having brightness of not less than a predetermined value and the region of less than the predetermined value in a quadrilateral frame may also be patterned to let the recognition unit  16  use the marker ID corresponding to the pattern. Further, the numeral range to be employed as the marker ID may also be established in advance to decide as the marker ID is not read when the read marker ID is not in the numeral range. 
     Next, the recognition unit  16  calculates positional coordinates and rotational coordinates of a reference object based on the picture of the reference object. The positional coordinates and the rotational coordinates of the reference object are values in the camera coordinate system. Further, the recognition unit  16  generates the transformation matrix M based on the positional coordinates and the rotational coordinates of the reference object. Details are as already described. 
     The guide performing unit  17  generates guide information that allows understanding of a difference between a first imaging condition estimated based on a picture of the reference object in the input image and a second imaging condition specified in advance. For example, the guide performing unit  17  estimates an imaging position of the input image based on the picture of the reference object in the input image. Then, the guide performing unit  17  calculates a difference between the appropriate imaging position set in the imaging condition information and the imaging position of the input image. Then, the guide performing unit  17  generates guide information to draw an arrow indicating a direction of filling the difference. The length and the like of the arrow may also be adjusted in accordance with the magnitude of the difference. 
     Here, a method of estimating an imaging position, which is one of the imaging conditions, is described. As a first method, a position (Xc 1 , Yc 1 , Zc 1 ) of the reference object calculated by the recognition unit  16  is utilized. The position (Xc 1 , Yc 1 , Zc 1 ) of the reference object is a position of the reference object in the camera coordinate system, where the focus of the camera is the origin. 
     As illustrated in  FIG. 3 , when the position of the reference object in the camera coordinate system is (Xc 1 , Yc 1 , Zc 1 ), the position of the focus of the camera in the marker coordinate system, where the center of the reference object is the origin, becomes (−Xc 1 , −Yc 1 , −Zc 1 ), on the contrary. That is, it is possible that the guide performing unit  17  estimates (−Xc 1 , −Yc 1 , −Zc 1 ) as the imaging position (position of the focus of the camera) in the marker coordinate system. 
     As a second method, the transformation matrix M generated by the recognition unit  16  is utilized. Specifically, the guide performing unit  17  obtains a column vector Am (Xm, Ym, Zm, 1) by a product of an inverse matrix M −1  of the transformation matrix M from the marker coordinate system to the camera coordinate system and the column vector Ac (Xc, Yc, Zc, 1). Specifically, the guide performing unit  17  obtains the column vector Am (Xm, Ym, Zm, 1) by the following formula 3.
 
 Am=M   −1   ·Ac   (Formula 3)
 
     When the imaging position is considered to approximately match the origin in the camera coordinate system, the imaging position is (0, 0, 0). Therefore, by substituting a column vector (0, 0, 0, 1) to Ac, it is possible that the guide performing unit  17  obtains to which point in the marker coordinate system the origin in the camera coordinate system corresponds, by the formula 3. That is, it is possible that the guide performing unit  17  estimates an imaging position in the marker coordinate system. 
     Next, an imaging direction, which is one of the imaging conditions, is described. It is possible that the guide performing unit  17  estimates an imaging direction of an input image as (−P 1   c , −Q 1   c , −R 1   c ) based on rotational coordinates (P 1   c , Q 1   c , R 1   c ) of the reference object calculated by the recognition unit  16 . 
     As above, it is possible that the guide performing unit  17  estimates imaging conditions of the input image. Hereinafter, the imaging position of the input image is supposed to be (Xcm, Ycm, Zcm). For example, (Xcm, Ycm, Zcm) is (−Xc 1 , −Yc 1 , −Zc 1 ). The imaging position included in the imaging condition information is supposed to be (Xcon, Ycon, Zcon). The imaging direction of the input image is supposed to be (Pcm, Qcm, Rcm). For example, (Pcm, Qcm, Rcm) is (−Pc 1 , −Qc 1 , −Rc 1 ). The imaging direction included in the imaging condition information is supposed to be (Pcon, Qcon, Rcon). 
     Next, the guide performing unit  17  calculates the difference between the imaging conditions of the input image and the imaging conditions included in the imaging condition information. When only either one of the imaging position and the imaging direction is employed as the imaging condition, the difference is calculated only for the imaging position or the imaging direction. 
     For example, the guide performing unit  17  calculates a difference (Xcon−Xcm, Ycon−Ycm, Zcon−Zcm) for each coordinate value in the marker coordinate system. When a value of the difference on the X axis is a positive value, the guide performing unit  17  generates an arrow indicating a left direction to a plane parallel to the display unit  13  (display) included in the information processing apparatus  1 . When the value of the difference on the X axis is a negative value, the guide performing unit  17  generates an arrow indicating a right direction. 
     When a value of the difference on the Y axis is a positive value, the guide performing unit  17  generates an arrow indicating an upward direction to a plane parallel to the display unit  13  (display) included in the information processing apparatus  1 . When the value of the difference on the Y axis is a negative value, the guide performing unit  17  generates an arrow indicating a downward direction. 
     When a value of the difference on the Z axis is a positive value, the guide performing unit  17  generates an arrow indicating a forward direction to a plane vertical to the display unit  13  (display) included in the information processing apparatus  1 . When the value of the difference on the Z axis is a negative value, the guide performing unit  17  generates an arrow indicating a backward direction. 
     Further, the guide performing unit  17  may also generate sound prompting alteration of the imaging conditions as the guide information instead of the arrow. For example, when the value of the difference on the X axis is a positive value, the guide performing unit  17  generates sound of “move to the left”. In this case, the guide information thus generated is outputted from, for example, a sound output unit (not illustrated) such as a speaker. 
     Further, the guide performing unit  17  calculates a difference between the rotational coordinates (Pcm, Qcm, Rcm) of the input image and the appropriate rotational coordinates (Pcon, Qcon, Rcon) set in the imaging condition information on each rotation axis, in the imaging direction as well. Then, the guide performing unit  17  generates guide information prompting rotation of the information processing apparatus in accordance with the difference in the rotational coordinates. For example, when a value of Pcon−Pcm is positive because P 1   c  indicates the rotation angle about the Xc axis, the guide performing unit  17  generates guide information so as to rotate the information processing apparatus  1  counterclockwise on the axis of ordinate that configures a plane parallel to the imaging device plane of the camera. 
     Further, when the difference becomes not more than a threshold, the guide performing unit  17  obtains a storage image. For example, the guide performing unit  17  stores an input image when the difference becomes not more than the threshold as the storage image in the storage unit  14 . Further, the guide performing unit  17  may also output a message of finishing imaging subject to observation to the operator via the display unit  13 . 
     Alternatively, when the difference becomes not more than the threshold, the guide performing unit  17  may also request the operator to press a determination button to image an observation object in the imaging position via the display unit  13 . Then, the guide performing unit  17  obtains an image from the imaging unit  12  to store the image as the storage image in the storage unit  14 . 
     The guide performing unit  17  associates the image data of the storage image with the time and date of imaging to store them in the storage unit  14 . Further, the guide performing unit  17  may also store the marker ID and information indicating the imaging conditions of the storage image in the storage unit  14 . 
     Next, the image generation unit  18  generates an image to be displayed on the display unit  13 . For example, the image generation unit  18  generates a synthesized image obtained by superposition display of the AR content on the taken image. The synthesized image is generated based on the transformation matrix M outputted by the recognition unit  16 , and the content information and the template information obtained from the management apparatus  2  by the communication unit  11 . 
     The image generation unit  18  generates the image to display the guide information based on the guide information generated by the guide performing unit  17 . For example, the image generation unit  18  synthesizes the guide display on the taken image. The image generation unit  18  may also synthesize the guide display on the synthesized image including the projection image of the AR object. 
     Next, descriptions are given to various types of information stored in the storage unit  14 . From the management apparatus  2 , the template information, the content information, and the imaging condition information are assumed to be provided to the information processing apparatus  1 . Then, the various types of information thus provided are stored in the storage unit  14 . 
       FIG. 10  illustrates a template information table. The template information table stores template information to define each template applied as model data of the AR object. The template information includes identification information of a template (template ID), coordinate information T 21  of each apex that configures the template, and configuration information T 22  of each plane that configures the template (specification of apex order and texture ID). 
     The apex order indicates the order of apexes that configure a plane. The texture ID indicates the identification information of a texture mapped on the plane. A reference point of the template is, for example, a 0th apex. By the information indicated in the template information table, the shape and the pattern of the three dimensional model are established. 
       FIG. 11  illustrates a content information table. The content information table stores content information regarding the AR content. In the content information table, a content ID of the AR content, the positional coordinates (Xm, Ym, Zm) of the reference point in the marker coordinate system, the rotational coordinates (Pm, Qm, Rm) in the marker coordinate system, the magnification D (Jx, Jy, Jz) using the AR template as a reference, the template ID of the AR template, the marker ID, and additional information are stored. 
     When image generation unit  18  generates a projection image of the AR object E, the AR template illustrated in  FIG. 10  is adjusted based on the content information (the position, the direction, and the size). In other words, specification of the position, the posture, and the size of the AR object E is carried out by setting the information managed by the content information table. The additional information is information added to the AR object E. As the additional information, a text, access information to a web page and a file, and the like are used. 
     For example, an AR content having a content ID of “C 1 ” illustrated in  FIG. 11  is configured with each apex obtained by zooming each apex coordinate defined as the AR template “T 1 ” in or out in the respective directions of Xm, Ym, Zm, rotating at the rotational coordinates (Pm 1 , Qm 1 , Rm 1 ), and translating in accordance with the positional coordinates (Xm 1 , Ym 1 , Zm 1 ). The AR content further carries out mapping of the additional information on a plane that configures the AR object E. 
     Next,  FIG. 12  illustrates an imaging condition information table. The imaging condition information table stores imaging condition information regarding the imaging conditions to be the reference when imaging the observation object. In the imaging condition information table, the marker ID, the imaging condition (Xcon, Ycon, Zcon) regarding the imaging position, and the imaging condition (Pcon, Qcon, Rcon) regarding the imaging direction are stored. 
     The imaging conditions may be information set by an administrator in advance and may also be the imaging position and the imaging direction of the image of the observation object that is taken initially. For example, as illustrated in  FIG. 7A , it is assumed that the operator finds the presence of the crack  304  and takes the image  300 . At this time, the imaging conditions to be the reference are generated based on the picture of the marker  306  (reference object) in the image  300 . The imaging conditions are generated in a method similar to the calculation method when the guide performing unit  17  estimates the imaging position of the input image. 
     Next, descriptions are given to a storage image table that stores a storage image.  FIG. 13  illustrates the storage image table. The storage image table stores the marker ID, the image data, the time and date of imaging, and the imaging conditions in which the storage image is taken, in association. In the example of  FIG. 13 , the imaging position and the imaging direction are stored as the imaging conditions. The image data may also be information indicating a location of image data storage, not the image data itself. 
     Next, descriptions are given to functional configuration of the management apparatus  2  according to the first embodiment.  FIG. 14  is a functional block diagram of the management apparatus. The management apparatus  2  has a communication unit  21 , a control unit  22 , and a storage unit  23 . The communication unit  21  is a processing unit to communicate with another computer. For example, the communication unit  21  carries out communication with the information processing apparatus  1 . 
     The control unit  22  is a processing unit to control various types of process of the entire management apparatus  2 . For example, the control unit  22  reads the content information, the template information, and the imaging condition information out of the storage unit  23  in accordance with a request from the information processing apparatus  1 . The request includes the identification information (marker ID) of the reference object recognized by the information processing apparatus  1 . Specifically, the control unit  22  reads the content information and the imaging condition information corresponding to the identification information out of the storage unit  23 . The template information of the template applied to the content is also read out together. 
     Then, the control unit  22  controls the communication unit  21  and sends the various types of information that are read out to the information processing apparatus  1 . In addition, when receiving the storage image from the information processing apparatus  1  via the communication unit  21 , the control unit  22  stores the storage image in the storage unit  23 . 
     The storage unit  23  stores various types of information. For example, the storage unit  23  stores the template information by the template information table similar to  FIG. 10 . In addition, the storage unit  23  stores the content information by the content information table similar to  FIG. 11 . Further, the storage unit  23  stores the imaging condition information by the imaging condition information table similar to  FIG. 12 . In addition, the storage unit  23  stores the storage image by the storage image table similar to  FIG. 13 . 
     Next, descriptions are given to a flow of guiding process performed by a guide program.  FIG. 15  illustrates a flowchart of guiding process. The guide program is a program in which a procedure of the guiding process performed by the control unit  15  of the information processing apparatus  1  is defined. 
     The control unit  15  carries out preprocess prior to performance of the guiding process. In the preprocess, the template information, the content information, and the imaging condition information are obtained from the management apparatus  2 . In addition, activation instruction of an AR display mode is carried out. The control unit  15  causes, for example, the imaging unit  12  to start imaging at a predetermined temporal interval and causes the recognition unit  16  to start marker sensing process regarding the taken image. Further, the control unit  15  displays the taken image taken by the imaging unit  12  on the display unit  13 . 
     When imaging is instructed from the control unit  15 , the imaging unit  12  obtains an image generated by the imaging device at a predetermined temporal interval and stores the image thus obtained in the storage unit  14 . In the storage unit  14 , a buffer to store a plurality of images is provided, and the image taken by the imaging unit  12  is stored in the buffer. For example, the buffer provided in the storage unit  14  is a buffer for display in which the image to be displayed by the display unit  13  is stored. The images stored in the buffer for display are displayed on the display unit  13  sequentially. 
     The recognition unit  16  obtains an image stored in the buffer provided in the storage unit  14  (Op. 1). The image obtained here becomes the input image. The recognition unit  16  decides whether a marker is recognized from the input image (Op. 3). For example, the recognition unit  16  recognizes a marker by using a template giving a shape of the marker to carry out template matching. 
     In the recognition of the marker (Op. 3), the recognition unit  16  carries out reading of the marker ID of the marker. In addition, the recognition unit  16  calculates the position (Xc 1 , Yc 1 , Zc 1 ) of the reference object and the rotational coordinates (P 1   c , Q 1   c , R 1   c ) of the reference object in the camera coordinate system based on the picture of the marker in the input image. In addition, the recognition unit  16  generates the transformation matrix M based on the position (Xc 1 , Yc 1 , Zc 1 ) of the reference object and the rotational coordinates (P 1   c , Q 1   c , R 1   c ) of the reference object. 
     When a marker is not recognized (no in Op. 3), the recognition unit  16  goes back to Op. 1. In contrast, when a marker is recognized (yes in Op. 3), the recognition unit  16  outputs the marker ID of the recognized marker to the guide performing unit  17  and the guide performing unit  17  decides presence of the observation object (Op. 5). That is, the guide performing unit  17  refers to the imaging condition information table and decides whether imaging conditions corresponding to the obtained marker ID are stored. When the conditions are stored, it is decided that an observation object associated with the marker recognized from the input image is present. 
     When there is no observation object (no in Op. 5), the image generation unit  18  generates a synthesized image in which a projection image of the AR content is superposed on the input image using the content information, the template information, and the transformation matrix M (Op. 7). Then, the display unit  13  displays the synthesized image (Op. 9). Then, the process is finished. 
     Here, when there is no observation object (no in Op. 5), the guide performing unit  17  may also decide whether or not to perform addition of the observation object. For example, when a user newly finds a crack, an input to add the crack as the observation object is performed. The guide performing unit  17  generates imaging conditions using an output by the recognition unit  16 . The generated imaging conditions are sent to the management apparatus  2  together with the marker ID to be managed. 
     In contrast, when there is an observation object (yes in Op. 5), the guide performing unit  17  calculates the imaging position and the imaging direction using the position (Xc 1 , Yc 1 , Zc 1 ) and the rotational coordinates (P 1   c , Q 1   c , R 1   c ) of the reference object in the camera coordinate system obtained from the recognition unit  16  (Op. 11). For example, the guide performing unit  17  calculates (−Xc 1 , −Yc 1 , −Zc 1 ) as the imaging position (Xcm, Ycm, Zcm) of the input image based on the position (Xc 1 , Yc 1 , Zc 1 ) of the reference object in the camera coordinate system. 
     Then, the guide performing unit  17  compares, for matching, the imaging conditions to be the reference with the calculated imaging conditions (Op. 13). Here, matching may be perfect matching and may also be approximate matching. For the threshold to decide whether or not to match, a value considering precision of human vision is set. 
     When the imaging conditions to be the reference does not match the calculated imaging conditions (no in Op. 13), the guide performing unit  17  generates guide information (Op. 15). For example, the guide information is information to draw an arrow prompting movement in a direction filling the difference between the imaging position included in the imaging conditions and the calculated imaging position. 
     Next, the image generation unit  18  generates a synthesized image using the content information, the template information, and the transformation matrix M and also draws guide display on the synthesized image based on the guide information (Op. 17). The position of drawing the guide information is arbitrary. For example, the guide display is carried out near the center or the like of the synthesized image. 
     Then, the display unit  13  displays the synthesized image including the guide display (Op. 19). After that, the control unit  15  decides whether to finish the process (Op. 21). For example, when an input of finishing the process is carried out by the user, finishing of the process is decided. When the process is finished (yes in Op. 21), the series of guiding process is finished directly. In contrast, when the process is not finished (no in Op. 21), the process goes back to Op. 1. 
     In addition, when the imaging conditions to be the reference match the calculated imaging conditions in Op. 13 (yes in Op. 13), the guide performing unit  17  stores the input image obtained in Op. 1 as the storage image (Op. 25). The guide performing unit  17  may also cause an operator to perform an imaging operation separately and then store the new image as the storage image. 
     Then, the control unit  15  sends the storage image to the management apparatus  2  via the communication unit  11  (Op. 27). The sending process may also be performed at other timing. For example, when an input of finishing a series of services from the operator, the communication unit  11  may also send all storage images stored during the series of services to the management apparatus  2 . Together with the storage image, various types of information stored in the storage image table illustrated in  FIG. 13  is also sent to the management apparatus  2 . 
       FIG. 16  is an example of a synthesized image including guide display. A synthesized image  400  including guide display includes piping  402 , a crack  404 , a marker  406 , the AR object E, guide display  408 , and guide display  410 . In the example of  FIG. 16 , guide display indicating movement to “left” and “back” is made to the operator. 
       FIG. 16  is an example of guide display when the difference between the imaging conditions to be the reference and the calculated imaging conditions is a positive value in the X value and a positive value in the Z value. According to the guide display, the user carries out movement to the left and the back until the information processing apparatus  1  decides that the imaging position to be the reference matches the actual imaging position, thereby allowing imaging of a storage image in a position matching the imaging position to be the reference. 
     As above, using the imaging position and the imaging direction relative to the reference object in the AR technique, it is possible that the information processing apparatus  1  in the present embodiment estimates the imaging position and the imaging direction regarding a plurality of images in which the observation object is imaged where the positional relationship with the reference object is unchanged. Then, by performing guidance indicating the difference between the reference and the current status of the imaging position and the imaging direction, it is possible that the information processing apparatus  1  causes the operator to take a plurality of images in which the observation object is taken in approximately identical imaging conditions. Eventually, it is possible that the management apparatus  2  gathers a storage image taken in approximately identical imaging conditions from the information processing apparatus  1 . Accordingly, it is possible to easily compare the change with time in an observation object even by human eyes. 
     Second Embodiment 
     In the first embodiment, descriptions are given to the information processing apparatus  1  that estimates the imaging conditions in the marker coordinate system from a picture of a marker to perform guidance. In the second embodiment, descriptions are given to an information processing apparatus  3  that estimates the imaging conditions from a region of a picture of a reference object in the image to perform guidance. 
     In the second embodiment, similar to the first embodiment, it is a premise that the positional relationship between the reference object and the observation object is unchanged and the reference object and the observation object are taken in one image. In the second embodiment, when a first image and a second image are taken in identical imaging conditions, attention is given to that a picture of a reference object in the first image and a picture of a reference object in the second image become in a same size and in a same shape. 
     The information processing apparatus  3  extracts a region of a reference object from an image to be the reference to utilize information of the extracted region as the imaging condition. The image to be the reference includes the reference object and the observation object. Then, when the observation object is newly imaged, guide display indicating the region of the reference object in the image to be the reference is displayed. For example, the guide display is a frame to fit the reference object. The operator moves to a position where the reference object fits in the frame to image the observation object. 
       FIGS. 17A and 17B  illustrate guide display according to the second embodiment.  FIG. 17A  illustrates an image  500  to be the reference. The information processing apparatus  3  generates the imaging conditions using a region of a picture of a marker  506  (reference object) in the image  500 . The image  500  also includes a crack  504  and piping  502 , which are observation objects. 
     The information processing apparatus  3  utilizes a region of the picture of the marker  506  recognized from the image  500  as the imaging conditions of the crack  504 . As described before, the region of the picture of the marker  506  is information allowing estimation of the imaging position and the imaging direction of the crack  504 . 
       FIG. 17B  illustrates a synthesized image  508  including guide display  516 . The synthesized image  508  includes a picture of a marker  514  at the time of imaging, piping  510 , and a crack  512 . The guide display  516  indicates a region of a picture of the marker  506  in the image  500  to be the reference. The operator moves to fit the marker  514  to the guide display  516  referring to the guide display  516 , thereby allowing taking of an image in imaging conditions similar to the image  500 . 
     The system according to the second embodiment includes the information processing apparatus  3  and the management apparatus  2 . Next, functional configuration of the information processing apparatus  3  according to the second embodiment is described.  FIG. 18  is a functional block diagram of an information processing apparatus according to the second embodiment. Regarding processing units that carry out process similar to the information processing apparatus  1  according to the first embodiment, an identical reference numeral is given thereto and also descriptions are omitted. 
     The information processing apparatus  3  includes a communication unit  11 , an imaging unit  12 , a display unit  13 , a storage unit  31 , and a control unit  32 . Further, the control unit  32  includes a recognition unit  33 , a condition generation unit  34 , a guide performing unit  35 , and an image generation unit  36 . 
     In a method similar to the recognition unit  16 , the recognition unit  33  recognizes a reference object from an input image and also obtains identification information to identify the reference object. Further, the recognition unit  33  generates a transformation matrix M similar to the recognition unit  16 . In addition, the recognition unit  33  generates region information of the reference object in the input image. For example, as the region information, a position of a pixel equivalent to a feature point of the reference object is obtained. 
     The condition generation unit  34  generates imaging conditions of the image to be the reference. For example, when addition of a new observation object is commanded by an operator, the condition generation unit  34  obtains the region information in the image to be the reference from the recognition unit  33 . Then, the condition generation unit  34  generates imaging condition information by associating the region information with the marker ID. The imaging condition information thus generated is sent to the management apparatus  2  via the communication unit  11 . 
     Next, similar to the guide performing unit  17 , the guide performing unit  35  generates guide information that allows understanding of a difference between a first imaging position estimated based on a picture of the reference object in the input image and a second imaging position specified in advance. It is to be noted that the guide performing unit  35  generates guide information to display region information of the reference object in the image to be the reference. 
     The image generation unit  36  generates a synthesized image similar to the image generation unit  18 . The image generation unit  36  draws a frame to fit a reference object on the input image based on the guide information. 
     Similar to the first embodiment, the storage unit  31  has a template information table, a content information table, an imaging condition information table, and a storage image table. It is to be noted that data configuration of the imaging condition information table is different from the first embodiment. 
       FIG. 19  illustrates an imaging condition information table in the second embodiment. In the second embodiment, as the imaging condition information, region information indicating a region of a marker, which is the reference object, is stored in association with the marker ID. 
     The region information is, for example, information indicating a position of a pixel equivalent to a plurality of feature points that configure the reference object. When a reference object in a square shape, such as the marker M, is employed, as illustrated in  FIG. 19 , pixels equivalent to four corners of the marker turns out to be the feature points. Then, the positions of the respective feature points are stored in the imaging condition information table as a first feature point position, a second feature point position, a third feature point position, and a fourth feature point position. Here, the coordinate value stored as the position of each feature point may be a value in any coordinate system. It is to be noted that, when coordinate values in the screen coordinate system are employed, it is possible to draw a frame for guide display without coordinate transformation. 
     In addition, in the storage unit  23  of the management apparatus  2  according to the second embodiment as well, an imaging condition information table having data configuration similar to  FIG. 19  is held. 
     Next, descriptions are given to a flow of various types of process regarding the second embodiment.  FIG. 20  illustrates a flowchart of guiding process according to the second embodiment. The guide program is a program in which a procedure of guiding process performed by the control unit  32  is defined. The control unit  32  carries out preprocess prior to the main guiding process. The preprocess is process similar to the first embodiment. 
     The recognition unit  33  obtains an image stored in a buffer provided in the storage unit  31  (Op. 31). The image obtained here becomes the input image. The recognition unit  33  decides whether a marker is recognized from the input image (Op. 33). In addition, the recognition unit  33  reads the marker ID similar to Op. 3. Further, similar to Op. 3, the recognition unit  33  calculates the positional coordinates (Xc 1 , Yc 1 , Zc 1 ) and the rotational coordinates (P 1   c , Q 1   c , R 1   c ) to generate the transformation matrix M. In addition, the recognition unit  33  generates region information of a picture of the reference object in the input image. 
     When the marker is not recognized (no in Op. 33), the recognition unit  33  goes back to Op. 31. In contrast, when the marker is recognized (yes in Op. 33), the recognition unit  33  outputs the marker ID to the guide performing unit  35 , and the guide performing unit  35  decides presence of an observation object (Op. 35). 
     When there is no observation object (no in Op. 35), the image generation unit  36  generates a synthesized image using the content information, the template information, and the transformation matrix M (Op. 37). Then, the display unit  13  displays the synthesized image (Op. 39). Then, the process is finished. Here, similar to the first embodiment, when there is no observation object, the guide performing unit  35  may also decide whether to perform addition of a new observation object. 
     In contrast, when there is an observation object (yes in Op. 35), the guide performing unit  35  obtains imaging condition information corresponding to the recognized marker ID from the storage unit  31  (Op. 41). As illustrated in  FIG. 19 , the imaging condition information is the region information of the reference object in the image to be the reference. 
     Next, the image generation unit  36  generates a synthesized image in which an AR content is projected on the input image using the content information, the template information, and the transformation matrix M, and also draws guide display based on the imaging condition information outputted from the guide performing unit  35  (Op. 43). 
     Then, the display unit  13  displays the synthesized image including the guide display (Op. 45). Next, the guide performing unit  35  decides whether or not a determination input to store an image is accepted from a user (Op. 47). When the reference object in a currently inputted image approximately matches the guide display, the user performs a determination input to make the input image to be a storage image. A button for determination input may also be provided on the synthesized image displayed in Op. 45. 
     When the determination input is not accepted (no in Op. 47), the control unit  32  decides whether or not to finish the process (Op. 49). For example, when an input of process finishing is carried out by the user (yes in Op. 49), finishing of the process is decided. When the process is finished, the series of guiding process is finished directly. In contrast, when the process is not finished (no in Op. 49), the process goes back to Op. 31. 
     When a determination input is accepted in Op. 47 (yes in Op. 47), the guide performing unit  35  stores the input image obtained in Op. 31 as a storage image (Op. 53). Then, the control unit  32  sends the storage image to the management apparatus  2  via the communication unit  11  (Op. 55). Then, the series of the process is finished. 
     Although the guide performing unit  35  decides presence of a determination input based on an input from the user in Op. 47, a storage image may also be stored similar to the first embodiment when region information of the reference object displayed as the guide display matches region information of the reference object in the input image. 
     Specifically, the guide performing unit  35  compares the region information of the reference object prescribed as the imaging conditions with the region information of the reference object in the input image. For the respective plurality of feature points of the marker M, the guide performing unit  35  decides whether the positions approximately match. For example, when approximate matching is decided for all four feature points, the guide performing unit  35  stores the input image as the storage image in the storage unit  31 . 
     As above, the information processing apparatus  3  according to the second embodiment displays the region information of the reference object in the reference image as information indicating the imaging position and the imaging direction of the storage image. The operator adjusts the imaging position and the imaging direction based on the region information of the reference object in the reference image, thereby allowing the information processing apparatus  3  to store the image taken in imaging conditions similar to the reference image. 
     First Modification 
     As a first modification of the first embodiment and the second embodiment, a plurality of imaging condition information items may also be associated with one reference object. For example, there is a case that an observation object to be imaged together with a certain reference object is different in the inspection service and the maintenance and management services. Therefore, the first modification manages different imaging condition information for each service type. As information to identify the service type, a scenario ID is utilized. 
     Firstly, an operator inputs a scenario ID to identify a service content that is performed by him/herself in advance, thereby uniquely specifying the identification information (marker ID) of the reference object and the imaging condition information in accordance with the scenario ID. The management apparatus  2  may also be configured to obtain the scenario ID together with the marker ID when accepting imaging condition information request from the information processing apparatus  1  or  3 , and may also be configured to accept specification of the scenario ID in advance. 
     Even in the inspection service, there is a case that an observation object to be imaged together with a certain reference object is different in an inspection service A and an inspection service B. In the first modification, even in an identical service type, the imaging condition information is further managed in accordance with specific contents of the activity. As the information to identify contents of an activity, a scene ID is utilized. After selecting the scenario ID, the operator further selects the scene ID, thereby uniquely specifying the imaging condition information corresponding to the service content and the contents of an activity. 
     As above, in the first modification, it is possible to set a plurality of imaging conditions relative to a certain reference object utilizing the scenario and the scene. Therefore, it is possible to set a plurality of imaging conditions to one reference object without installing a reference object for each scenario and scene and to reduce installation load of a reference object. 
       FIG. 21  illustrates an imaging condition information table in the first modification. The example of  FIG. 21  illustrates when the first modification is applied to the imaging condition information table according to the first embodiment. The imaging condition information table stores a marker ID, a scenario ID, a scene ID, and imaging conditions in association. The imaging conditions are an imaging position and an imaging direction. The information processing apparatus  1  according to the first modification is capable of switching the imaging conditions for a marker ID “M 1 ” in accordance with the scenario ID and the scene ID. The embodiment may also set only either one of the scenario ID and the scene ID. 
     Second Modification 
     The management apparatus  2  may also perform guiding process. The control unit  22  of the management apparatus  2  performs, for example, Op. 1, Op. 3, Op. 5, Op. 7, Op. 9, Op. 11, Op. 13, Op. 15, Op. 17, Op. 19, Op. 21, and Op. 25 illustrated in  FIG. 15 . In Op. 9 and Op. 19, a synthesized image is sent to the information processing apparatus  1  and displayed in the information processing apparatus  1 . In Op. 1 and Op. 21, an input image is received from the information processing apparatus  1 . Similarly, the guiding process according to the second embodiment may also be performed by the control unit  22  of the management apparatus  2 . 
     In the second modification, the template information, the content information, and the imaging condition information may not be provided to the information processing apparatus  1 . Since the information processing apparatus  1  or the information processing apparatus  3  only carries out imaging of an image and display of an image, so that the process load is reduced. 
     Third Modification 
     Further, the information processing apparatus  1  according to the first embodiment may also record the imaging position and the imaging direction relative to the marker as log information to generate a movement locus of a user. Specifically, the information processing apparatus  1  recognizes the reference object and also obtains the imaging position and the imaging direction relative to the reference object in a method similar to the first embodiment. Then, the information processing apparatus  1  records the identification information (marker ID) of the recognized reference object in association with the imaging position, the imaging direction, and the time and date of imaging as log information. Further, a user ID to identify a user may also be included in the log information. 
     The recording of log information is continued from recognition of the marker to finishing of the recognition, and as a new marker is recognized, recording of log information including the new marker ID starts. In such a manner, the information processing apparatus  1  is capable of gathering log information regarding user movement (imaging position relative to the marker) during the recognition of the marker. 
     Further, the information processing apparatus  1  according to the present modification may also generate a movement locus of a user based on the gathered log information. Specifically, map data in which positional information (information on an installation position in a facility) of each marker in the real space is associated with map information in the facility is prepared in advance. Then, the information processing apparatus plots a position (imaging position) of a user relative to each marker on the map, thereby mapping the change in position of the user on the map data as a movement locus. 
     The movement locus of the user is recorded as marker relative coordinates in the marker coordinate system. The map data is set in a global coordinate system to hold the marker position and direction in the global coordinates. The information processing apparatus coordinate transforms the marker relative coordinates of the movement locus of the user to the global coordinate system using the marker position on the map data as a reference, thereby plotting the movement locus on the map data. 
       FIG. 22  is a schematic diagram of map data where movement loci of a user are mapped.  FIG. 22  is an example of mapping movement loci  602 ,  604 ,  606 ,  608 ,  610 , and  612  of a user on the map data including a workplace  600  and markers M 1 , M 2 , M 3 , M 4 , M 5 , and M 6  installed in the workplace  600 . By narrowing a placement interval of the markers is narrowed, a movement locus of a user may also be tracked without interruption. 
     The movement locus  602  is generated from log information including a marker ID of the marker M 1 . The movement locus  604  is generated from log information including a marker ID of the marker M 2 . The movement locus  606  is generated from log information including a marker ID of the marker M 3 . The movement locus  608  is generated from log information including a marker ID of the marker M 4 . The movement locus  610  is generated from log information including a marker ID of the marker M 5 . The movement locus  612  is generated from log information including a marker ID of the marker M 6 . 
     Specifically, the movement locus  602  has a plotted imaging position of the log information including the marker ID of the marker M 1 . Further, the respective plotted points are connected in the order of earlier time and date of imaging in the log information. 
     In such a manner, the log information generated during recognition of each marker is mapped on the map data, thereby allowing visual recognition of a staying location and a movement locus of a user. For example, in  FIG. 22 , it is understood that the user stays in the area indicated by  614 . Further, in the map data, staying time and date of a user may also be displayed together. 
     Another Application 
     The technique disclosed in the embodiments is applicable other than to control the imaging condition to take an image subject to observation. Here, descriptions are given to another application. 
     Even when a marker is recognized in a taken image, there is a case that an AR object is not superposition displayed on the taken image. This is a case where the placement position of the AR object is out of the area capable of superposition display on the taken image. Specifically, when the operator is in a state close to a marker, an AR content set in distance from the marker is not included in the synthesized image. Therefore, it is not possible for the user to understand the AR content. 
     In order to avoid such a situation, the above embodiments are applied. That is, appropriate imaging conditions are guided to the user. Specifically, an administrator sets in imaging conditions according to the imaging position and the imaging direction in advance. Then, guide display is performed in an embodiment capable of understanding a difference between the imaging conditions supposed from the taken image taken by the operator and the imaging conditions set in advance. The operator carries out movement in accordance with the guide display, thereby allowing avoidance of the situation where the AR object associated with the reference object is not displayed due to the influence of the imaging conditions. 
     Hardware Configuration Example 
     Descriptions are given to hardware configuration of the information processing apparatus  1  and the management apparatus  2  illustrated in each embodiment.  FIG. 23  is a hardware configuration example of an information processing apparatus in each embodiment. The information processing apparatus  1  and the information processing apparatus  3  are achieved by a computer  1000 . That is, the functional blocks illustrated in  FIG. 9  and  FIG. 18  are achieved by, for example, the hardware configuration illustrated in  FIG. 23 . 
     The computer  1000  includes, for example, a processor  1001 , a random access memory (RAM)  1002 , a read only memory (ROM)  1003 , a drive apparatus  1004 , a storage medium  1005 , an input interface (input I/F)  1006 , an input device  1007 , an output interface (output I/F)  1008 , an output device  1009 , a communication interface (communication I/F)  1010 , a camera module  1011 , an acceleration sensor  1012 , an angular rate sensor  1013 , a display interface (display I/F)  1014 , a display device  1015 , bus  1016 , and the like. The respective hardware is connected via the bus  1016 . 
     The communication interface  1010  carries out control of communication via the network N. The communication controlled by the communication interface  1010  may also be in an embodiment of accessing the network N via a wireless base station utilizing wireless communication. One example of the communication interface  1010  is a network interface card (NIC). The input interface  1006  is connected to the input device  1007  and transmits an input signal received from the input device  1007  to the processor  1001 . The output interface  1008  is connected to the output device  1009  and causes the output device  1009  to perform an output in accordance with an instruction of the processor  1001 . One example of the input interface  1006  and the output interface  1008  is an I/O controller. 
     The input device  1007  is an apparatus that sends an input signal in accordance with an operation. The input signal is, for example, a key apparatus, such as a keyboard and a button mounted in a main body of the computer  1000 , and a pointing device, such as a mouse and a touch panel. The output device  1009  is an apparatus that outputs information in accordance with control of the processor  1001 . The output device  1009  is, for example, a sound output apparatus, such as a speaker. 
     The display interface  1014  is connected to the display device  1015 . The display interface  1014  displays image information written by the processor  1001  in the buffer for display provided in the display interface  1014  on the display device  1015 . One example of the display interface  1014  is a graphic card and a graphic chip. The display device  1015  is an apparatus that outputs information in accordance with control of the processor  1001 . For the display device  1015 , an image output apparatus, such as a display, a transmissive display, and the like are used. 
     When a transmissive display is used, the projection image of the AR content is not synthesized with the taken image but, for example, may also be controlled to be displayed in an appropriate position in the transmissive display. Thus, a user obtains vision in a state of matching the real space and the AR content. In addition, for example, an input/output apparatus, such as a touch screen, is used as the input device  1007  and the display device  1015 . In addition, instead of building the input device  1007  and the display device  1015  inside the computer  1000 , the input device  1007  and the display device  1015 , for example, may also be connected to the computer  1000  from outside. 
     The RAM  1002  is a readable and writable memory apparatus, and for example, a semiconductor memory, such as a static RAM (SRAM) and a dynamic RAM (DRAM), a flash memory other than a RAM, or the like may also be used. The ROM  1003  includes a programmable ROM (PROM). 
     The drive apparatus  1004  is an apparatus that carries out at least either one of reading and writing of information stored in the storage medium  1005 . The storage medium  1005  stores the information written by the drive apparatus  1004 . The storage medium  1005  is, for example, at least one of the storage medium of the type, such as a hard disk, a solid state drive (SSD), a compact disk (CD), a digital versatile disk (DVD), and a blue-ray disk. In addition, for example, the computer  1000  includes the drive apparatus  1004  compatible with the type of the storage medium  1005  in the computer  1000 . 
     The camera module  1011  includes an imaging device (image sensor) and the imaging device writes data obtained by photoelectric conversion in an image buffer for input image included in the camera module  1011 . The acceleration sensor  1012  measures the acceleration that applies to the acceleration sensor  1012 . The angular rate sensor  1013  measures the angular rate of a behavior by the angular rate sensor  1013 . 
     The processor  1001  reads a program stored in the ROM  1003  or the storage medium  1005  to the RAM  1002  and carries out process in accordance with a procedure of the read program. For example, the functions of the control unit  15  are achieved by the processor  1001  carrying out control of other hardware based on the guide program according to the first embodiment. For example, the functions of the control unit  32  are achieved by the processor  1001  carrying out control of other hardware based on a guide program according to the second embodiment. 
     The functions of the communication unit  11  are achieved by the processor  1001  performing data communication by control of the communication interface  1010  and storing the received data in the storage medium  1005 . 
     The functions of the storage unit  14  and the storage unit  31  are achieved by the ROM  1003  and the storage medium  1005  storing a program file and a data file and the RAM  1002  being used as a work area for the processor  1001 . For example, the content information, the template information, the imaging condition information, and the like are stored in the RAM  1002 . 
     The functions of the imaging unit  12  are achieved by the camera module  1011  writing image data in the image buffer for input image and the processor  1001  reading the image data in the image buffer for input image. The image data is, in a monitoring mode, for example, written in the image buffer for input image and also written in the buffer for display of the display device  1015  in parallel. 
     In addition, the functions of the display unit  13  are achieved by the image data generated by the processor  1001  being written in the buffer for display provided with the display interface  1014  and the display device  1015  carrying out display of the image data in the buffer for display. 
     Next,  FIG. 24  illustrates a configuration example of a program that runs in the computer  1000 . In the computer  1000 , an operating system (OS)  3002  that controls a group of hardware runs. The processor  1001  runs in the procedure in accordance with the OS  3002  to carry out control and management of hardware (HW)  3001 , thereby performing process by an application program (AP)  3004  and a middleware (MW)  3003  on the HW  3001 . 
     In the computer  1000 , a program, such as the OS  3002 , the MW  3003 , and the AP  3004 , is, for example, read by the RAM  1002  and performed by the processor  1001 . In addition, the guide program described in each embodiment is, for example, a program that is called from the AP  3004  as the MW  3003 . 
     Alternatively, an AR control program including the guide program, for example, is a program to achieve the AR function as the AP  3004 . The AR control program is stored in the storage medium  1005 . The storage medium  1005  may be distributed in a state of being independent as the guide program according to the present embodiments or storing the AR control program including the guide program, separate from the computer  1000  main body. 
     Next, descriptions are given to hardware configuration of the management apparatus  2  in each embodiment.  FIG. 25  is a hardware configuration example of a management apparatus. The management apparatus  2  is achieved by a computer  2000 . The management apparatus  2  is achieved by, for example, the hardware configuration illustrated in  FIG. 25 . The computer  2000  includes, for example, a processor  2001 , a RAM  2002 , a ROM  2003 , a drive apparatus  2004 , a storage medium  2005 , an input interface (input I/F)  2006 , an input device  2007 , an output interface (output I/F)  2008 , an output device  2009 , a communication interface (communication I/F)  2010 , a storage area network (SAN) interface (SAN I/F)  2011 , a bus  2012 , and the like. The respective hardware is connected via the bus  2012 . 
     For example, the processor  2001  is hardware similar to the processor  1001 . The RAM  2002  is, for example, hardware similar to the RAM  1002 . The ROM  2003  is, for example, hardware similar to the ROM  1003 . The drive apparatus  2004  is, for example, hardware similar to the drive apparatus  1004 . The storage medium  2005  is, for example, hardware similar to the storage medium  1005 . The input interface (input I/F)  2006  is, for example, hardware similar to the input interface  1006 . The input device  2007  is, for example, hardware similar to the input device  1007 . 
     The output interface (output I/F)  2008  is, for example, hardware similar to the output interface  1008 . The output device  2009  is, for example, hardware similar to the output device  1009 . The communication interface (communication I/F)  2010  is, for example, hardware similar to the communication interface  1010 . The storage area network (SAN) interface (SAN I/F)  2011  is an interface to connect the computer  2000  to the SAN and includes a host bus adapter (HBA). 
     The processor  2001  reads a program stored in the ROM  2003  and the storage medium  2005  and carries out process in accordance with the procedure of the read program. At that time, the RAM  2002  is used as a work area for the processor  2001 . The program includes a program according to various types of process in the management apparatus  2 . For example, the program is a program in which process selecting the template information, the content information, the imaging condition information to be provided to the computer  1000  and the like are described. 
     The management apparatus  2  stores various types of information by the ROM  2003  and the storage medium  2005  storing a program file and a data file or the RAM  2002  being used as a work area for the processor  2001 . The processor  2001  carries out communication process by controlling the communication interface  2010 . 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.