Patent Publication Number: US-7907171-B2

Title: Notebook information processor and projective transformation parameter calculating method

Description:
RELATED APPLICATIONS 
     The present application is based on, and claims priority from, Japan Application Number 2008-109302, filed Apr. 18, 2008, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a notebook information processor, and projective transformation parameter calculating method. 
     2. Description of the Related Art 
     With a notebook information processor such as conventional PDA terminal and laptop type PC, by way of example, when a user such as a businessman wants to scan a document such as a paper document not at his desk in an office with a well-equipped environment but at a meeting, when visiting a customer, and in a hotel of a business trip destination, it is required to additionally bring a portable scanner or a digital camera. 
     When additionally bringing the portable scanner, a general commercially available notebook information processor and a portable scanner weigh about 1 to 2 kg and 1.4 kg, respectively, so that they weigh about 3 kg in total and are too heavy for the user to bring. In addition, the user has to keep an installation area of both the notebook information processor and the scanner when scanning. 
     Therefore, although the digital camera is often used in place of the portable scanner without bringing the latter, in this case, however, it is difficult to straightforwardly photograph the document without using a tripod or the like, so that it is required to convert the document photographed by the digital camera as if this is straightforwardly photographed. 
     That is to say, when using the notebook information processor such as a notebook personal computer and the digital camera in place of the image scanner, it is required to use a technique to correct distortion of a viewpoint when photographing by an existing projective transformation technique. 
     Conventionally, there is a technique to calculate a projective transformation parameter for performing the projective transformation on the document as if this is straightforwardly photographed in an over head projector (OHP) type photographing device or the like. 
     For example, the OHP-type photographing device disclosed in JP-A-2006-74512 uses the rectangle of the outline of the seat of which shape is known as the reference polygon, and compares the rectangle with the rectangle identified by the contour of the seat image, thereby obtaining the projective transformation parameter. 
     However, in the conventional projective transformation technique (such as JP-A-2006-74512), for example, the rectangular seat of which four corners are square is required as the rectangle used for calculating the projective transformation parameter, and there is a problem that when the four corners of the seat are not square and the seat is not rectangular, the rectangular figure of which four corners are square is required to be separately provided or the apex signs such as the corner marks are required to be drawn on the seat so as to detect the coordinates of the four corners of the seat. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     A notebook information processor according to one aspect of the present invention, includes a lid including an image photographing unit and a display, and a main body including a storage unit and a control unit, wherein the control unit includes a live view displaying unit that displays a live view obtained by photographing at least a portion of the main body within a photographing area of the image photographing unit on the display, a rectangle detecting unit that detects a rectangle for calculating a projective transformation parameter from the live view displayed on the display by the live view displaying unit, a projective transformation parameter calculating unit that calculates the projective transformation parameter from a coordinate of the rectangle detected by the rectangle detecting unit, and a still image obtaining unit that performs a projective transformation on the live view so as to obtain a live view photographed from a front direction, using the projective transformation parameter calculated by the projective transformation parameter calculating unit, obtains a still image from the live view after the projective transformation, and stores the still image in the storage unit. 
     A projective transformation parameter calculating method according to another aspect of the present invention is executed by a notebook information processor, including a lid including an image photographing unit and a display, and a main body including a storage unit and a control unit. The method includes a live view displaying step of displaying a live view obtained by photographing at least a portion of the main body within a photographing area of the image photographing unit on the display, a rectangle detecting step of detecting a rectangle for calculating a projective transformation parameter from the live view displayed on the display by the live view displaying unit, a projective transformation parameter calculating step of calculating the projective transformation parameter from a coordinate of the rectangle detected by the rectangle detecting unit, and a still image obtaining step of performing a projective transformation on the live view so as to obtain a live view photographed from a front direction, using the projective transformation parameter calculated by the projective transformation parameter calculating unit, obtains a still image from the live view after the projective transformation, and stores the still image in the storage unit. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an outline drawing showing one example of a configuration of the notebook information processor; 
         FIG. 2  is a block diagram showing one example of a configuration of the notebook information processor; 
         FIG. 3  is a view showing one example of a projective transformation according to the embodiment; 
         FIG. 4  is a view showing one example of the projective transformation according to the embodiment; 
         FIG. 5  is a view showing one example of images before and after the projective transformation according to the embodiment; 
         FIG. 6  is a flowchart showing one example of a still image obtaining process of the notebook information processor according to the embodiment; and 
         FIG. 7  is a flowchart showing one example of a projective transformation parameter calculating process of the notebook information processor according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following describes an embodiment of a notebook information processor and a projective transformation parameter calculating method for such a device and a method according to the present invention in detail with reference to the drawings. The embodiment is illustrative only, and is not intended to limit the present invention in any way. 
     OVERVIEW OF THE INVENTION 
     The following outlines the present invention, and then, a configuration and processing of the present invention are explained in detail with reference to  FIG. 1 . 
     The invention has schematically following basic features. 
     As shown in  FIG. 1 , the notebook information processor  100  is composed of a lid  1  including at least an image photographing unit  116  and a display  114 , and a main body  2  including at least a storage unit and a control unit. The main body  2  includes a touch pad  3  and a keyboard  4  formed of at least one key top  5 , and a rectangular sign  6  is displayed on an upper surface of the main body  2 . 
     The control unit of the notebook information processor  100  displays a live view obtained by photographing at least a portion of the main body  2  within a photographing area of the image photographing unit  116  on the display  114 . 
     The “live view” is a moving image and a still image photographed by the image photographing unit  116 , displayed on the display  114  such that a user may check in real time for adjusting the photographing area of the image photographing unit  116 . 
     The control unit of the notebook information processor  100  detects a rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , a shape of the key top  5 , and the rectangular sign  6 ) for calculating a projective transformation parameter from the live view displayed on the display  114 . A dimension of the rectangle for calculating the projective transformation parameter is not necessarily known, and one having a rectangular shape may be used. 
     The control unit of the notebook information processor  100  may detect at least a portion of the touch pad  3  as the rectangle for calculating the projective transformation parameter. The control unit of the notebook information processor  100  may detect at least a portion of the keyboard  4  as the rectangle for calculating the projective transformation parameter. The control unit of the notebook information processor  100  may detect at least a portion of the shape of at least one key top  5  forming the keyboard  4  as the rectangle for calculating the projective transformation parameter. The control unit of the notebook information processor  100  may detect at least a portion of the sign  6  as the rectangle for calculating the projective transformation parameter. The control unit of the notebook information processor  100  may detect at least a portion of an appearance of the main body  2  as the rectangle for calculating the projective transformation parameter. 
     The control unit of the notebook information processor may allow the user to specify in advance the rectangular shape to be detected for calculating the projective transformation parameter. That is to say, the control unit of the notebook information processor  100  may allow the user to specify the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) for calculating the projective transformation parameter, from the live view displayed on the display  114 , using an input unit (such as the touch pad  3  and the mouse). 
     The control unit of the notebook information processor  100  calculates the projective transformation parameter from a coordinate of the detected rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ). 
     The control unit of the notebook information processor  100  performs the projective transformation on the live view to obtain the live view photographed from a front direction using the calculated projective transformation parameter, obtains the still image of a document put on the main body  2  from the live view after the projective transformation, and stores the still image in the storage unit. 
     The “document” is a photographing object (subject) of the still image by the image photographing unit  116 , and includes not only a planar one such as a paper document but also a stereoscopic one. 
     Configuration of the Notebook Information Processor  100   
     The following first describes a configuration of a notebook information processor  100  with reference to  FIGS. 2 to 5 . 
       FIG. 2  conceptually shows only parts related to the present invention. 
     As shown in  FIG. 2 , in general, the notebook information processor  100  is provided with the keyboard  4  formed of at least one key top  5 , the touch pad  3 , the display  114 , the image photographing unit  116 , the storage unit  106 , control unit  102 , an input/output control interface  108 , and a communication control interface  104 . 
     In  FIG. 2 , the control unit  102  is formed by a Central Processing Unit (CPU) which controls the notebook information processor  100  totally, or the like. The communication control interface  104  connects to a communication device (not shown) such as a router connected to a communication channel or the like, and the input/output control interface  108  connected to the keyboard  4  formed of at least one key top  5 , the touch pad  3 , the display  114 , and the image photographing unit  116 . The storage unit  106  stores various databases and tables. The units composing the notebook information processor  100  are communicatably connected through an optional communication channel. Further, the notebook information processor  100  are communicatably connected to a network  300  via a communication device such as a router, and a wired or wireless communication line such as a dedicated line. 
     In  FIG. 2 , the image photographing unit  116  is a video camera or a digital camera that has a function to photograph the moving image for the live view obtained by photographing at least a portion of the main body  2  within the photographing area, and is formed of, for example, a charge coupled device (CCD). The image photographing unit  116  may be incorporated in the notebook information processor  100 . The image photographing unit  116  may be detachably placed in the notebook information processor  100 , electrified by the notebook information processor  100 , and communicatably connected to the notebook information processor  100  (for example, a USB-connected WEB camera or digital camera may be used as the image photographing unit  116 ). The image photographing unit  116  may be rotatably placed in the notebook information processor  100  such that a photographing direction is changeable. 
     The notebook information processor  100  may further have a rotational angle sensor (not shown) that detects a rotational angle when rotated so as to change the photographing direction of the image photographing unit  116 . The notebook information processor  100  may have the lid  1  in which at least the image photographing unit  116  is placed, and the main body  2  in which at least the keyboard  4  is placed, and may further have an open angle sensor (not shown) that detects an open angle of the lid  1  with respect to the main body  2 , and a motor (not shown) that adjusts the rotational angle of the image photographing unit  116 . The rotational angle sensor and the open angle sensor have a function to detect a rotational angle γ of the image photographing unit  116  and an open angle θ of the notebook information processor  100 , and is, for example, a gyro sensor that detects an angular speed and the angle. The motor has a function to rotate the image photographing unit  116 . 
     In  FIG. 2 , the various databases and tables (such as an image database  106   a  and parameter table  106   b ) stored in the storage unit  106  are storage units such as fixed disk devices. The storage units store various programs, various tables, various databases, and the like used in various processes. 
     Out of each component of the storage unit  106 , the image database  106   a  stores various moving images and still images, and for example, stores the moving images and the still images after various image processings (such as the projective transformation) by the control unit  102 , in addition to the moving image of the live view photographed by the image photographing unit  116  and the still image of the document put on the main body  2 . 
     The parameter table  106   b  stores the projective transformation parameter calculated from the coordinate of the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) detected by the control unit  102 . 
     The communication control interface  104  controls communication between the notebook information processor  100  and a network  300  (or a communication device such as a router). That is to say, the communication control interface  104  has a function to communicate data to another terminal through a communication line. The communication control interface  104  may have a function to communicate data to the image photographing unit  116  detachably connected to the notebook information processor  100  through the communication line. 
     The input/output control interface  108  controls the keyboard  4  formed of at least one key top  5 , the touch pad  3 , the display  114 , and the image photographing unit  116 . The keyboard  4  corresponds to the keyboard placed in the main body  2 , and the display  114  corresponds to the display (monitor) placed in the lid  1 . 
     The control unit  102  has an internal memory that stores a control program such as an operating system (OS), a program defining various procedures, and required data. The control unit  102  performs information processing for executing various processings by the programs or the like. The control unit  102  conceptually has a live view displaying unit  102   a , a rectangle detecting unit  102   b , a projective transformation parameter calculating unit  102   c , and a still image obtaining unit  102   d.    
     Out of them, the live view displaying unit  102   a  displays the live view obtained by photographing at least a portion of the main body  2  within the photographing area of the image photographing unit  116  on the display  114 . 
     The rectangle detecting unit  102   b  detects the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) for calculating the projective transformation parameter from the live view displayed on the display  114  by the live view displaying unit  102   a.    
     The rectangle detecting unit  102   b  may detect at least a portion of the touch pad  3  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the keyboard  4  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the shape of at least one key top  5  forming the keyboard  4  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the sign  6  (such as the rectangular label adhered in advance for the projective transformation and the rectangular label normally adhered (such as the Windows (registered trademark) label)) as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the appearance of the main body  2  as the rectangle for calculating the projective transformation parameter. 
     The rectangle detecting unit  102   b  may allow the user to specify in advance the rectangular shape to be detected for calculating the projective transformation parameter. That is to say, the rectangle detecting unit  102   b  may allow the user to specify the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) for calculating the projective transformation parameter from the live view displayed on the display  114 , using an optional input unit such as the touch pad  3  and the mouse. 
     The projective transformation parameter calculating unit  102   c  calculates the projective transformation parameter from the coordinate of the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) detected by the rectangle detecting unit  102   b , and stores the projective transformation parameter in the parameter table  106   b . A detail of a projective transformation parameter calculating process performed by the projective transformation parameter calculating unit  102   c  is described in the following projective transformation parameter calculating process. 
     The still image obtaining unit  102   d  performs the projective transformation on the live view displayed on the display  114  by the live view displaying unit  102   a  so as to obtain the live view photographed from the front direction, using the projective transformation parameter calculated by the projective transformation parameter calculating unit  102   c , obtains the still image of the document put on the main body  2  from the live view after the projective transformation, and stores the still image in the image database  106   a.    
     The projective transformation performed by the still image obtaining unit  102   d  is explained with reference to  FIGS. 3 and 4 . 
     The projective transformation performed by the still image obtaining unit  102   d , for example, is executed by restoring the image photographed by the image photographing unit  116  to an original state by using an inverse projective transformation. An example of the projective transformation is explained below. When performing the projective transformation, a vanishing point of the image on an imaging plane  70  being an image plane photographed by the image photographing unit  116  is obtained. For example, when an imaging plane shape  71  being an image shape on the imaging plane  70  is the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) as shown in  FIG. 3 , the two vanishing points S 1  and S 2  are obtained. The vanishing point is the point at which extended lines of two straight lines, which are formed parallel in an actual shape, cross to each other, when projecting a predetermined shape. By thus obtaining the vanishing point, an original size before the projection and the projective transformation parameters (a 11  to a 32 ) being the parameters when performing the projective transformation are obtained based on the vanishing point, and the projective transformation is performed using a following [Equation 1]. That is to say, the projective transformation is performed by obtaining a coordinate (u,v,1) after the projective transformation from a coordinate (x,y,1) before the projective transformation by the [Equation 1]. 
     
       
         
           
             
               
                 
                   
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     By thus performing the projective transformation on the coordinate of the imaging plane shape  71 , which is the coordinate before the projective transformation, a projectively transformed shape  75 , which is the shape after the projective transformation, may be obtained as shown in  FIG. 4  by obtaining the coordinate after the projective transformation. The projectively transformed shape  75  is similar to an original shape  76 , which is the shape when seeing the original imaged by the image photographing unit  116  from the front direction, that is to say, the shape when seeing the imaged plane in the vertical direction. Various conventional technologies other than the above-described technique may be used as the projective transformation. 
     An example of the image after the projective transformation performed by the still image obtaining unit  102   d  is explained with reference to  FIG. 5 . 
     As shown in  FIG. 5 , an upper portion in  FIG. 5  is a view of the live view before the projective transformation obtained by photographing at least a portion of the main body  2  within the photographing area of the image photographing unit  116 , displayed on the display  114  by the live view displaying unit  102   a . A lower portion in  FIG. 5  is a view of the still image obtained from the live view after the projective transformation obtained by performing the projective transformation on the live view before the projective transformation displayed on the display  114  by the live view displaying unit  102   a  so as to obtain the live view photographed from the front direction, using the projective transformation parameter calculated by the projective transformation parameter calculating unit  102   c.    
     Processing of the Notebook Information Processor  100   
     The following describes in detail one example of a still image obtaining process of the notebook information processor  100  according to the embodiment as configured above with reference to  FIGS. 6 and 7 . 
     Still Image Obtaining Process 
     The following describes details of the still image obtaining process with reference to  FIG. 6 . 
     As shown in  FIG. 6 , the live view displaying unit  102   a  displays the live view obtained by photographing at least a portion of the main body  2  within the photographing area of the image photographing unit  116  on the display  114  (step SA- 1 ). 
     The rectangle detecting unit  102   b  detects the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) for calculating the projective transformation parameter from the live view displayed on the display  114  by the process by the live view displaying unit  102   a  (step SA- 2 ). 
     The rectangle detecting unit  102   b  may detect at least a portion of the touch pad  3  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the keyboard  4  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the shape of at least one key top  5  forming the keyboard  4  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the sign  6  as the rectangle for calculating the projective transformation parameter. The rectangle detecting unit  102   b  may detect at least a portion of the appearance of the main body  2  as the rectangle for calculating the projective transformation parameter. 
     The projective transformation parameter calculating unit  102   c  calculates the projective transformation parameter from the coordinate of the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) detected by the process by the rectangle detecting unit  102   b , and stores the projective transformation parameter in the parameter table  106   b  (step SA- 3 ). The projective transformation parameter calculating process performed by the projective transformation parameter calculating unit  102   c  at the step SA- 3  is described in detail in a following projective transformation parameter calculating process. 
     The still image obtaining unit  102   d  performs the projective transformation as described above on the live view displayed on the display  114  by the process by the live view displaying unit  102   a  so as to obtain the live view photographed from the front direction using the projective transformation parameter calculated by the process by the projective transformation parameter calculating unit  102   c , obtains the still image of the document put on the main body  2 , and stores the still image in the image database  106   a  (step SA- 4 ). 
     Projective Transformation Parameter Calculating Process 
     The following describes details of a projective transformation parameter calculating process performed by the projective transformation parameter calculating unit  102   c  at step the above-described SA- 3  with reference to  FIG. 7 . 
     As shown in  FIG. 7 , the projective transformation parameter calculating unit  102   c  calculates the vanishing point used in law of painting such as law of perspective based on the coordinate (c 1  (x 1 ,y 1 ) to c 4  (x 4 ,y 4 ) in FIG.  3 ) of the rectangle (imaging plane shape  71  in  FIG. 3 ) for calculating the projective transformation parameter detected by the process by the rectangle detecting unit  102   b  from the photographed image such as the moving image photographed by the image photographing unit  116  (step SB- 1 ). The coordinates of the vanishing points S 1  and S 2  calculated by the process by the projective transformation parameter calculating unit  102   c  are represented in a following [Equation 2].
 
v1(x1,y1), v2(x2,y2)  [Equation 2]
 
     The projective transformation parameter calculating unit  102   c  calculates a vanishing line indicating an angle of the subject on a three-dimensional space by assigning the coordinates of the vanishing points S 1  and S 2  in the [Equation 2] calculated at the step SB- 1  to the following [Equation 3], and the projective transformation parameter calculating unit  102   c  calculates a focal length f (vertical distance f to the imaging plane  70  in  FIG. 4 ) by assigning the coordinates of the vanishing points S 1  and S 2  in the [Equation 2] to the following [Equation 4] (step SB- 2 ).
 
( y 1− y 2) x +( x 2− x 1) y+x 1 y 2− x 2 y 1=0  [Equation 3]
 
 f =√{square root over (− x 1· x 2− y 1· y 2)}  [Equation 4]
 
     The projective transformation parameter calculating unit  102   c  calculates the coordinates (C 1  (X 1 ,Y 1 ,Z 1 ) to C 4  (X 4 ,Y 4 ,Z 4 ) in  FIG. 4 ) of four corners and horizontal and vertical lengths of the rectangle (original shape  76  in  FIG. 4 ) on the three-dimensional space by the vanishing points, the vanishing line, and the focal length calculated at the steps SB- 1  and SB- 2  and the following perspective transformation equation [Equation 5] (step SB- 3 ). 
     
       
         
           
             
               
                 
                   
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     The projective transformation parameter calculating unit  102   c  calculates the projective transformation parameters (a 11  to a 32 ) of the [Equation 6] by the coordinate (x,y,1) before the projective transformation detected at the step SB- 1  and the coordinate (u,v,1) after the projective transformation calculated at the step SB- 3  (step SB- 4 ). Various conventional technologies other than the above-described technique may be used as the projective transformation parameter calculation. 
     
       
         
           
             
               
                 
                   
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     In this way, the projective transformation parameter calculating unit  102   c  calculates the projective transformation parameter from the coordinate of the rectangle (such as the main body  2 , the touch pad  3 , the keyboard  4 , the shape of the key top  5 , and the rectangular sign  6 ) detected by the rectangle detecting unit  102   b , and stores the projective transformation parameter in the parameter table  106   b.    
     Other Embodiments 
     Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth. 
     For example, in the embodiment, the notebook information processor  100  performs various processes as a stand-alone device. However, the notebook information processor  100  can be configured to perform processes in response to request from a client terminal, which is a separate unit, and return the process results to the client terminal. 
     All the automatic processes explained in the present embodiment can be, entirely or partially, carried out manually. Similarly, all the manual processes explained in the present embodiment can be, entirely or partially, carried out automatically by a known method. 
     The process procedures, the control procedures, specific names, information including registration data for each process and various parameters such as search conditions, display example, and database construction, mentioned in the description and drawings can be changed as required unless otherwise specified. 
     The constituent elements of the notebook information processor  100  are merely conceptual and may not necessarily physically resemble the structures shown in the drawings. For instance, the apparatus need not necessarily have the structure that is illustrated. 
     For example, the process functions performed by each device of the notebook information processor  100 , especially the each process function performed by the control unit  102 , can be entirely or partially realized by CPU and a computer program executed by the CPU or by a hardware using wired logic. The computer program, recorded on a recording medium to be described later, can be mechanically read by the notebook information processor  100  as the situation demands. In other words, the storage unit such as read-only memory (ROM) or hard disk (HD) stores the computer program that can work in coordination with OS to issue commands to the CPU and cause the CPU to perform various processes. The computer program is first loaded to the random access memory (RAM), and forms a control unit  102  in collaboration with the CPU. 
     Alternatively, the computer program can be stored in any application program server connected to the notebook information processor  100  via the network  300 , and can be fully or partially loaded as the situation demands. 
     The computer-readable recording medium on which the computer program can be stored may be a portable type such as flexible disk, magneto optic (MO) disk, ROM, erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), compact disk-read-only memory (CD-ROM), digital versatile disk (DVD), or a communication medium that stores the computer program for a short term such as communication channels or carrier waves that transmit the computer program over the network  300  such as local area network (LAN), wide area network (WAN), and the Internet. 
     Computer program refers to a data processing method written in any computer language and written method, and can have software codes and binary codes in any format. The computer program can be a dispersed form in the form of a plurality of modules or libraries, or can perform various functions in collaboration with a different program such as the OS. Any known configuration in the each device according to the embodiment can be used for reading the recording medium. Similarly, any known process procedure for reading or installing the computer program can be used. 
     The storage unit  106  is a fixed disk device such as RAM, ROM, and HD or flexible disk, optical disk, and stores therein various programs, tables, databases (such as the image database  106   a  and the parameter table  106   b ), and files required for various processes. 
     The notebook information processor  100  can also be connected to any existing personal computer, workstation, etc. and can be operated by executing software (that includes computer program, data, etc.) that implements the method according to the present invention in the personal computer or workstation. 
     The distribution and integration of the device are not limited to those illustrated in the figures. The device as a whole or in parts can be functionally or physically distributed or integrated in an arbitrary unit according to various attachments or how the device is to be used. 
     According to the present invention, it is not required to separately provide the seat for obtaining the rectangle for calculating the projective transformation parameter or the apex signs such as the corner marks. Thereby, the present invention has an effect of automatically and efficiently calculating the projective transformation parameter by detecting the specific rectangular shape in the live view, thereby obtaining the still image as if the document such as the paper document put on the main body  2  is photographed from the front direction. 
     According to the present invention, it is possible to detect the rectangle from the shape of the touch pad  3  normally equipped to the main body  2  or the like of the notebook information processor  100 , thereby calculating the projective transformation parameter. Thereby, the present invention has an effect of efficiently calculating the projective transformation parameter without separately providing the rectangle for calculating the projective transformation parameter to the notebook information processor  100  having the touch pad  3 . 
     According to the present invention, it is possible to detect the rectangle from the shape of the keyboard  4  normally equipped to the main body  2  or the like of the notebook information processor  100 , thereby calculating the projective transformation parameter. Thereby, the present invention has an effect of efficiently calculating the projective transformation parameter without separately providing the rectangle for calculating the projective transformation parameter to the notebook information processor  100  having the keyboard  4 . 
     According to the present invention, it is possible to detect the rectangle from the shape of the key top  5  of keyboard  4  normally equipped to the main body  2  or the like of the notebook information processor  100 , thereby calculating the projective transformation parameter. Thereby, the present invention has an effect of efficiently calculating the projective transformation parameter without separately providing the rectangle for calculating the projective transformation parameter to the notebook information processor  100  having the keyboard  4 . 
     According to the present invention, the sign  6  (such as the rectangular label (such as the Windows (registered trademark) label) normally adhered on the main body  2 ) or the like displayed on the main body  2  or the like of the notebook information processor  100  may be used. 
     According to the present invention, it is possible to use the entire main body  2  as the rectangle used for calculating the projective transformation parameter. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.