Patent Publication Number: US-2006013508-A1

Title: Projection apparatus and image acquisition method

Description:
TECHNICAL FIELD  
      The present invention relates to a projection apparatus and an image acquisition method which project a document image onto a screen.  
     BACKGROUND ART  
      In conventional presentation on projects, commodity or so, a document stored as data in a personal computer (PC) or a document comprised of texts and diagrams or so is projected, magnified, onto a screen by a projector. A typical projector has a structure which uses an image converting element such as a liquid crystal or a micro-mirror array, and converts image information of a document output as video signals from a PC to projection light.  
      In presentation, persons who participate in the presentation often directly write comments, underlines or so on a projected document (on the screen). Therefore, it is often the case where a white board is used as a projection screen. In case where a presenter such as a document creator wants to use comments or so written by a participant, e.g., in case where the presenter wants to correct the contents of the document referring to the comments or so or add the comments or so to the document, a so-called electronic board is used as a screen and comments or so handwritten on the electronic board are saved by a hard copy (print) or the image of a white board or so is picked up by a digital camera prepared separately to be saved as image data. For example, Japanese Patent Laid-Open No. 2001-169211 describes a projector equipped with a camera, though the usage is totally different.  
      In case of using handwritten information on a screen which is saved as mentioned above, however, when a document to be used in presentation contains a large number of sheets (pages), it is difficult to determine the correlation between the number of pieces of saved handwritten information and the number of pages of the document after presentation. In case where the number of pieces of saved handwritten information does not match with the number of pages of the document (normally, the number of pieces of saved handwritten information is often smaller than the number of pages of the document), particularly, it is difficult to determine the correlation between the saved handwritten information and the pages of the document.  
      The present invention has been made to overcome the conventional problem and aims at providing a projection apparatus and an image acquisition method which can use handwritten information on a screen.  
     DISCLOSURE OF INVENTION  
      One of preferable modes of the invention is a projection apparatus that projects a document image, generated based on a document, onto a screen, and comprises:  
      a projection section ( 14 ) which projects the document image onto the screen (S);  
      an image pickup section ( 16 ) which picks up an image of the screen (S);  
      a processor section ( 11 ) which acquires a first picked-up image on the screen (S) by causing the projection section ( 14 ) to project the document image onto the screen (S) and causing the image pickup section ( 16 ) to pick up the image of the screen (S), and acquires a second picked-up image of only recorded information recorded on the screen (S) by causing the projection section ( 14 ) to stop projecting the document image onto the screen (S) and causing the image pickup section ( 16 ) to pick up the image of the screen (S); and  
      an image memory section ( 4 ) which stores the first picked-up image and the second picked-up image, acquired by the processor section ( 11 ), as data in association with each other.  
      Another preferable mode of the invention is an image acquisition method that acquires information on a screen as an image, and comprises:  
      a step which projects document image generated based on a document onto the screen;  
      a step which acquires a first picked-up image including recorded information recorded on the screen by picking up an image of the screen;  
      a step which stops projection of the document image;  
      a step which acquires a second picked-up image of only the recorded information recorded on the screen by picking up the image of the screen; and  
      a step which stores the first picked-up image and the second picked-up image in association with each other. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      These objects and other objects and advantages of the present invention will become more apparent upon reading of is the following detailed description and the accompanying drawings in which:  
       FIG. 1  is a structural diagram of a projection system illustrating first and fourth to sixth embodiments of the present invention;  
       FIG. 2  is a block diagram showing the schematic structures of a projector and personal computer common to the first, fourth and fifth embodiments;  
       FIG. 3  is a flowchart illustrating the operation of the projector according to the first embodiment;  
       FIG. 4A  is an explanatory diagram showing one example of a document image to be stored in the first embodiment;  
       FIG. 4B  is an explanatory diagram showing one example of a handwritten information image to be stored in the first embodiment;  
       FIG. 5  is a structural diagram of a projection system common to second, third and eighth embodiments of the invention;  
       FIG. 6  is a block diagram showing the schematic structures of a projector and personal computer in the projection system;  
       FIG. 7  is a flowchart illustrating the operation of the projector according to the second, third and eighth embodiments;  
       FIG. 8  is an explanatory diagram showing a text recognized area in a document image according to the second, third and eighth embodiments;  
       FIG. 9  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the second, third and eighth embodiments;  
       FIG. 10  is a flowchart illustrating the operation of the projector according to the third embodiment of the invention;  
       FIG. 11  is an explanatory diagram showing a text recognized area in a document image according to the third embodiment;  
       FIG. 12  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the third embodiment;  
       FIG. 13  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the fourth embodiment;  
       FIG. 14  is a flowchart illustrating the operations of the projector and personal computer during projection of a document according to the fifth embodiment;  
       FIG. 15  is an explanatory diagram showing one example of a projected image according to the fifth embodiment;  
       FIG. 16  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the fifth embodiment;  
       FIG. 17  is a block diagram showing the schematic structures of the projector and personal computer according to the sixth embodiment;  
       FIG. 18  is a flowchart illustrating the operations of the projector and personal computer during projection of a document according to the sixth embodiment;  
       FIG. 19  is an explanatory diagram showing display history information which is created by the personal computer according to the sixth embodiment;  
       FIG. 20  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the sixth embodiment;  
       FIG. 21  is a structural diagram of a projection system illustrating a seventh embodiment of the present invention;  
       FIG. 22  is a block diagram showing the schematic structures of a projector and personal computer which constitute the projection system;  
       FIG. 23  is a flowchart illustrating the operations of the projector and personal computer during projection of a document according to the seventh embodiment;  
       FIG. 24  is an explanatory diagram showing image management data which is created by the personal computer according to the seventh embodiment;  
       FIG. 25  is a flowchart illustrating the procedures of an image pasting routine done by the personal computer according to the seventh embodiment;  
       FIG. 26  is a flowchart illustrating the operations of the projector and personal computer during projection of a document according to the eighth embodiment of the invention;  
       FIG. 27  is an explanatory diagram showing the contents of appended data of an image file which is recorded by the projector according to the eighth embodiment; and  
       FIG. 28  is an explanatory diagram showing display history information which is created by the personal computer according to the eighth embodiment.  
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
      One preferred embodiment of the present invention is described below with reference to the accompanying drawings.  
     First Embodiment  
       FIG. 1  is a structural diagram of a projection system according to the first embodiment. This projection system projects the display image of a document comprised of texts and diagrams or so onto a screen S, such as a white board, acquires texts or so written on the screen S by image pickup and saves the handwritten texts or so and the display image as one set. The projection system comprises a projector  1  and a personal computer (PC)  2 . The projector  1  and the PC  2  are connected together by an RGB cable  3 . The projector  1  is used to project a document in presentation or so and incorporates a digital camera for picking up the image of the screen S, such as a white board. A projection section la and a image pickup section  1   b  are provided side by side on the front side of the main body of the projector  1 . The projection section  1   a  comprises an optical system, such as a projection lens, which projects a display image. The image pickup section  1   b  comprises an optical system, such as an image pickup lens, which picks up an image. Further, the projector  1  has a slot (not shown) where a memory card  4  is to be loaded and data is given to the PC  2  via the memory card  4 .  
       FIG. 2  is a block diagram showing the schematic structures of the projector  1  and the PC  2 . The projector  1  mainly comprises a CPU (Central Processing Unit)  11 , a ROM (Read Only Memory)  12 , a RAM (Random Access Memory)  13 , a display section  14 , a key input section  15 , a digital camera section  16  and a card interface circuit  17 . The projector  1  also has an input terminal  18  for RGB signals to which the RGB cable  3  is connected.  
      The card interface circuit  17  serves to carry out data input/output with respect to the memory card  4 . The memory card  4  stores images or so picked up by the digital camera section  16 .  
      The display section  14  projects a document image of a document (comprised of texts and diagrams or so) output from the PC  2  onto the screen S and includes a light source, an image converting element, a drive circuit and an optical system.  
      The light source, like a krypton lamp, emits light. The image converting element converts light from the light source to projection light and comprised of a liquid crystal or micro-mirror array.  
      The drive circuit drives the image converting element in accordance with RGB signals input from the input terminal  18 .  
      The optical system comprises the projection lens or so in the projection section  1   a.    
      The key input section  15  is prepared for a user to operate the projector  1  and has a plurality of operation buttons, such as an operation button for an image pickup operation.  
      The digital camera section  16  picks up the image of the screen S as a subject as a predetermined operation button constituting the key input section  15  is depressed. The digital camera section  16  has an optical system, an image pickup element and an image data processing circuit (none shown). The optical system comprises the image pickup lens or so in the image pickup section  1   b.  The image pickup element photoelectrically converts an optical image formed by the optical system into an image signal and comprises a CMOS sensor, CCD or the like. The image data processing circuit compresses a picked-up image, output from the image pickup element and converted to a digital signal. The digital camera section  16  finally records generated imaged data as an image file of the JPEG format in the memory card  4  via the card interface circuit  17 .  
      A program is stored in the ROM  12 . The CPU  11  controls the aforementioned individual sections using the RAM  13  as a work memory in accordance with the program stored in the ROM  12 . Specifically, the CPU  11  acquires a picked-up image including a document and recorded information recorded on the screen S by causing the display section  14  to project a document image onto the screen S and causing the digital camera section  16  to pick up the image of the screen S. The CPU  11  acquires a picked-up image containing only the recorded information by causing the display section  14  to stop projecting a document image onto the screen S and causing the digital camera section  16  to pick up the image of the screen S. The CPU  11  stores the two acquired images as data in the memory card  4  in association with each other.  
      The input terminal  18  is provided in an unillustrated input image processing circuit connected to the CPU  11 .  
      The PC  2  supplies the projector  1  with data of a document to be projected onto the screen S and comprises a RAM  22 , a memory device  23 , an input device  24 , a display device  25  and a card interface circuit  26 .  
      The PC  2  has an output terminal  27  for RGB signals to which the RGB cable  3  is connected. The output terminal  27  is provided in an unillustrated image signal processing circuit connected to the CPU  11 .  
      The memory device  23  comprises a hard disk or so with a relatively large memory capacity and stores a predetermined presentation program for creating and editing a document for presentation. The presentation program includes a plurality of commands selectable by a user, such as a command to instruct the execution of a process of pasting an image of a handwritten text or so to the display image of the document. The memory device  23  stores data of a document comprised of texts and diagrams or so to be projected onto the screen S as a document file.  
      The CPU  21  controls the individual sections using the RAM  13  as a work memory in accordance with the program stored in the memory device  23 .  
      The input device  24  has a plurality of keys provided on its main body and a mouse or so connected to the main body.  
      The card interface circuit  26  comprises an LCD, a drive circuit for the LCD and so forth. The card interface circuit  26  serves to carry out data input/output with respect to the memory card  4 .  
      The operations of the projector  1  and PC  2  are described below.  
      As a user designates a document to be projected onto the screen S by operating the input device  24  of the PC  2 , the PC  2  responsively acquires its document data from the memory device  23 . The PC  2  outputs the acquired document data as RGB signals to the projector  1  via the RGB cable  3 .  
      The projector  1  projects the document, output as RGB signals from the PC  2 , onto the screen S. During projection of a display image displayed on the screen S, the projector  1  records handwritten information according to a flowchart illustrated in  FIG. 3 . It is premised in the following description that handwritten information, such as comments and underlines, is directly written on the screen S by a participant in the presentation.  
      The projector  1  (CPU  11 ) determines whether or not an image pickup operation has been done (step SA 1 ).  
      When the user depresses an operation button for image pickup on the key input section  15 , the projector  1  determines that an image pickup operation has been performed (YES in step SA 1 ). When such a decision is made, the projector  1  controls the digital camera section  16  to pick up the then image of the screen S or the image of the screen S in a document-projected state where a display image based on document information. The projector  1  temporarily stores data of the picked-up image, e.g., a picked-up image as shown in  FIG. 4A  (hereinafter called “document image”) G 1  in the RAM  13  as index information (step SA 2 ).  
      Next, the projector  1  stops projecting the document being projected, irradiates only white light onto the screen S to set a non-projection state of the display image and picks up the image of the screen S. Accordingly, the projector  1  acquires a picked-up image of handwritten texts or so as shown in, for example,  FIG. 4B  (hereinafter called. “handwritten information image”) G 2  (step SA 3 ). Then, the projector  1  records the document image G 1  and the handwritten information image G 2  as a set in the memory card  4  loaded into the main body (step SA 4 ). The projector  1  records both images G 1  and G 2  to which file names different only in the end (for example, “AAAA-1.jpg” and “AAAA-2.jpg”) are affixed. Apparently, this process is to record both images G 1  and G 2  in association with each other so as to make it possible to identify that the images G 1  and G 2  were recorded in the same image pickup operation. This completes a single handwritten information recording process. During projection of a document, the projector  1  repeats the above-described process every time the user performs the image pickup operation.  
      According to the embodiment, a document image G 1  and handwritten information image G 2  are recorded in the memory card  4  in association with each other. Therefore, a user or the creator or so of the document can use the handwritten information by loading the memory card  4  into the PC  2  after the end of presentation or the like and displaying the handwritten information image G 2  stored in the memory card  4 . What is more, the user can easily know which projection of which document the handwritten information was written.  
      Although the image of the screen S is picked up continuously in accordance with a predetermined image pickup operation by a user to acquire a document image G 1  and a handwritten information image G 2  consecutively in the embodiment, the following way may be taken.  
      The projector  1  may acquire a document image G 1  after acquiring a handwritten information image G 2 . Further, the timing for acquiring both images G 1  and G 2  may be the time at which a document to be projected is changed, not the time at which an image pickup operation is performed. For example, the projector  1  may be provided with a detection section which detects switching of a document based on a change in the contents of RGB signals sent from the PC  2 . Even when the detection section detects switching of the document, the projector  1  keeps projecting a display image before document switching and picks up the image of the screen S after which it picks up the image of the screen S in a non-projection state. That is, the projector  1  may be constructed in such a way as to acquire and record a document image G 1  and handwritten information image G 2  for every document. In case where there is no handwritten information, however, the projector  1  acquires and records only a document image G 1 .  
      The projector  1  may also be constructed in such a way as to acquire a document image G 1  at the timing when handwritten information is not written on the screen S, such as immediately after a document to be projected is switched or immediately after a page of the document is changed.  
      For example, immediately after a page of the document is changed, the projector  1  picks up the image of the screen S in a state where handwritten information is not written to thereby acquire a document image G 1  and pre-stores the acquired document image G 1  in the RAM  13  or so. The projector  1  acquires only a handwritten information image G 2  when a user performs an image pickup operation.  
      In the embodiment, the projector  1  records the acquired document image G 1  and handwritten information image G 2  in the memory card  4 . In case where the projector  1  has such a structure as to be able to output data to the PC  2 , the projector  1  may output data (image files) of the document image G 1  and handwritten information image G 2  one after another to the PC  2  which in turn may store the data of the document image G 1  and handwritten information image G 2  as one set in the memory device  23  or so. In this case, the PC  2  can store the original data of the stored document image G 1  and the data of the handwritten information image G 2  output from the projector  1  in the memory device  23  or so in association with each other.  
      The foregoing description of the embodiment has discussed an example in which the projector  1  projects the display image of a document onto the screen S based on RGB signals output from the PC  2 . However, the projector  1  can read out original data (document file) recorded in a predetermined format from the memory card  4  and project the display image of the document onto the screen S.  
     Second Embodiment  
      The second embodiment of the invention is described next.  
      An image pickup apparatus according to the second embodiment of the invention is designed in such a way as to acquire a page number of a document through character recognition and records the acquired page number, taken as index information indicating the correlation between the page of the document and a handwritten information image, and a handwritten information image as a set.  
       FIG. 5  is a structural diagram of a projection system according to the second embodiment. The projection system, like that of the first embodiment, comprises the projector  1  and the PC  2 .  FIG. 6  is a block diagram showing the schematic structures of the projector  1  and the PC  2  in this embodiment. The projector  1  and PC  2  in the embodiment respectively have USB terminals  19  and  28  and are connected together by a USB cable  31 . The USB terminals  19  and  28  are actually provided in an USB interface circuit (not shown) connected to CPUs  11  and  21 . Accordingly, the PC  2  can send data to the projector  1 .  
      Like or same reference symbols are given to those components which are the same as the corresponding components of the first embodiment and their redundant descriptions are omitted.  
      The operations of the projector  1  and PC  2  in the embodiment are described below. First, the operation of the projector  1  is discussed.  
      Based on a flowchart shown in  FIG. 7 , the projector  1  executes a process of recording handwritten information during projection of a document output from the PC  2  as RGB signals. It is premised here that handwritten information, such as comments and underlines, is directly written on the screen S by a participant in the presentation.  
      The projector  1  acquires the document image G 1  and handwritten information image G 2  as shown in  FIGS. 4A and 4B  by performing an image pickup process according to an image pickup operation performed by a user (step SB 1 ). This process is the same as the process in steps SA 1  to SA 3  in the first embodiment illustrated in  FIG. 3 .  
      Next, the projector  1  acquires header information of the document which is projected (step SB 2 ).  
      The projector  1  determines whether or not the header information has information indicating a print position as position information of a page number (step SB 3 ).  
      When it is determined that the header information has position information of a page number (YES in step SB 3 ), the projector  1  acquires the page number from image data of the document image G 1  by performing OCR (Optical Character Recognition) on the position of the page number (area corresponding to the position indicated by the position information) on the document image G 1  (step SB 4 ). Thereafter, the projector  1  records the acquired page number, taken as index information, and the handwritten information image G 2  as a set in the memory card  4  loaded into the main body (step SB 5 ).  
      When it is determined that the header information acquired from the PC  2  does not have position information of a page number (NO in step SB 3 ), on the other hand, the projector  1  performs OCR on four corners and the bottom center portion a to e of the document image G 1  as shown in  FIG. 8 , i.e., recognition areas which are likely portions where a page number is printed (displayed), and converts the images of the individual recognition areas (a to e) to text data (step SB 6 ). The projector  1  checks the converted text data (step SB 7 ).  
      Then, the projector  1  determines whether or not the text data comprises a numeral (step SB 8 ).  
      When it is determined that there is a numeral (YES in step SB 8 ), the projector  1  records the numeral, taken as a page number, and a handwritten information image G 2  as a set in the memory card  4  (step SB 5 ).  
      When it is determined that no numeral is present in any of the areas (NO in step SB 8 ), the projector  1  causes the user to input the page number through prompting or so (step SB 9 ). When the page number is input, the projector  1  records the input page number and the handwritten information image G 2  as a set into the memory card  4  (step SB 5 ). This completes a single handwritten information recording process. During projection of a document, the projector  1  repeats the above-described process every time the user performs the image pickup operation.  
      It is to be noted that the process in the step SB 5  is to record the acquired page number and handwritten information image G 2  in association with each other so as to make it possible to identify that the page number and handwritten information image G 2  were recorded in the same image pickup operation. This process is to give the same file names different only in an identifier portion indicating a data type, such as “AAAA.jpg” and “AAAA.txt”, to the page number and handwritten information image G 2  or record both data in the memory card  4  in the determined order, for example, with consecutive recording addresses given.  
      When the memory card  4  where a set of an associated handwritten information image G 2  and page number or plural sets of associated handwritten information images G 2  and page numbers are recorded is loaded and then a command to execute an image pasting routine is selected, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 9 . It is premised here that a document to be processed is designed beforehand by a user.  
      The PC  2  first reads the handwritten information image G 2  from the memory card  4  (step SC 1 ). Further, the PC  2  reads a page number corresponding to the handwritten information image G 2  (step SC 2 ). Next, based on the read page number, the PC  2  acquires the handwritten information image G 2  stored in the memory device  23  and pastes this handwritten information image G 2  to a corresponding page of the document designated beforehand (step SC 3 ). Then, the PC  2  repeats the above-described sequence of processes in order by the number of handwritten information images G 2  recorded in the memory card  4 .  
      According to the embodiment, as apparent from the above, the page number of a document is acquired through character recognition and the acquired page number as index information is stored as a set with a handwritten information image. Therefore, the user can automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds.  
      In the embodiment, the order of acquiring a document image G 1  and a handwritten information image G 2  and the timing of acquiring the document image G 1  can be changed as needed as per the first embodiment.  
      In the embodiment, the projector  1  acquires the header information of a projected document from the PC  2 . But, the system may take such a structure as not to acquire the header information of a document from the PC  2 . That is, the projector  1  and the PC  2  need not be connected together by the USB cable  31  and the same hardware structure as that of the first embodiment may be employed. In this case, the processes in steps SB 2  to SB 4  in the routine shown in  FIG. 7  may be omitted.  
      In case where the header information of a document is not acquired from the PC  2 , the projector  1  may operate as follows. For example, the projector  1  records a set of an associated handwritten information image G 2  and page number or plural sets of associated handwritten information images G 2  and page numbers in the memory card  4  by the same procedures as done in the first embodiment. Then, the projector  1  first performs the process of step SB 6  for a plurality of document images G 1  at a time in response to the user&#39;s request. The projector  1  checks text data at the same position (area) in every document image G 1  (step SB 7 ). If the text data comprises a numeral (YES in step SB 8 ), the projector  1  may use the numeral acquired from the same position of each document image G 1  in step SB 5  as a page number and may record each page number and a corresponding handwritten information image G 2  as a set in the memory card  4 . In this case, the page number corresponding to the handwritten information image G 2  can be acquired more accurately.  
      In the embodiment, the projector  1  records the acquired document image G 1  and page number in the memory card  4 . However, the system structure may be modified in such a way that the projector  1  outputs document images G 1  and page numbers to the PC  2  via the USB cable  31  one after another and stores them in the PC  2  (memory device  23  or so). Further, the system structure may be modified in such a way that the projector  1  outputs the document image G 1  and handwritten information image G 2 , acquired in step SB 1 , directly to the PC  2  and the PC  2  performs a process concerning acquisition of a page number, which is done by the projector  1  in the second embodiment, before the above-described image pasting routine.  
      The second embodiment, like the first embodiment, can be adapted to the projector which has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data. In this case, the projector  1  may be allowed to perform the above-described image pasting routine by the PC  2  in accordance with a predetermined operation by a user or every time an image pickup operation is performed by the user.  
     Third Embodiment  
      The third embodiment of the invention is described next. This embodiment is the projection system of the second embodiment as shown in  FIGS. 5 and 6  which is so modified as to record a page title present on each page of a document, in place of a page number, and a handwritten information image G 2  as a set in the memory card  4 .  
      It is assumed that a document stored as a document file in the memory device  23  has header information including position information indicating a print position of a page title present on each page as information on the document.  
      The operations of the projector  1  and PC  2  according to the invention in the embodiment are discussed below. To begin with, the operation of the projector  1  is discussed.  
      Based on a flowchart shown in  FIG. 10 , the projector  1  records handwritten information during projection of a document output from the PC  2  as RGB signals. It is premised here that handwritten information, such as comments and underlines, is directly written on the screen S by a participant in the presentation.  
      In this embodiment, like the first embodiment, the projector  1  acquires the document image G 1  and handwritten information image G 2  as shown in  FIGS. 4A and 4B  by performing an image pickup process according to an image pickup operation performed by a user during image projection (step SD 1 ). This process is the same as the process in steps SA 1  to SA 3  in the first embodiment illustrated in  FIG. 3 .  
      Next, the projector  1  acquires header information of the document which is projected (step SD 2 ).  
      The projector  1  determines whether or not the acquired header information has position information of a page title (step SD 3 ).  
      When it is determined that the header information has position information of a page title (YES in step SD 3 ), the projector  1  performs OCR at the page title position (area) on the document image G 1 , indicated by the position information. Then, the projector  1  acquires a page title from image data of the document image G 1  (step SD 4 ).  
      Thereafter, the projector  1  records the acquired page title, taken as index information, and the handwritten information image G 2  as a set in the memory card  4  loaded into the main body (step SD 5 ).  
      When it is determined that the header information acquired from the PC  2  does not have position information of a page title (NO in step SD 3 ), on the other hand, the projector  1  performs OCR on an upper portion f of four of the document image G 1  as shown in  FIG. 11 , i.e., a recognition area which is a likely portion where a page title is printed (displayed), and converts the image of that recognition area (f) to text data (step SD 6 ).  
      Then, the projector  1  determines whether or not text data is present in the recognition area (step SD 7 ).  
      When it is determined that there is text data in the recognition area (YES in step SD 7 ), the projector  1  sets, for example, two lines from the top of the text as a page title (step SD 8 ) and records the numeral, taken as a page number, and a handwritten information image G 2  as a set in the memory card  4  (step SD 5 ).  
      When it is determined that there is no text present (NO in step SD 7 ), the projector  1  records only the handwritten information image G 2  in the memory card  4  (step SD 5 ).  
      It is to be noted that the process in the step SD 5  is to record the acquired page title and handwritten information image G 2  in association with each other so as to make it possible to identify that the page title and handwritten information image G 2  were recorded in the same image pickup operation. The specific process contents are the same as those of the second embodiment.  
      When the memory card  4  where a set of an associated handwritten information image G 2  and page title or plural sets of associated handwritten information images G 2  and page titles are recorded is loaded and then a command to execute an image pasting routine is selected, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 12 . It is premised here that a document to be processed is designed beforehand by a user.  
      The PC  2  first reads the handwritten information image G 2  from the memory card  4  (step SE 1 ). Further, the PC  2  reads title data corresponding to the read handwritten information image G 2  from the memory card  4  (step SE 2 ).  
      The PC  2  determines whether or not the title data read from the memory card  4  has data of a page title (step SE 3 ).  
      When it is determined that the title data read from the memory card  4  has data of a page title (YES in step SE 3 ), the PC  2  acquires data of page title on all the pages of the document designated beforehand and stored in the memory device  23 . The PC  2  compares the page title data acquired from the memory device  23  with the page title data read from the memory card  4  as text data. Then, the PC  2  pastes the handwritten information image G 2  to that page which contains a greater number of characters which match (step SE 4 ).  
      In case where it is determined that the title data read from the memory card  4  does not have page title data (NO in step SE 3 ), the PC  2  causes the user to perform manual pasting, considering that there is no page title. That is, the PC  2  causes the user to designate a corresponding page by means of a display or the like (step SE 5 ). Then, the PC  2  repeats the above-described sequence of processes in order by the number of handwritten information images G 2  recorded in the memory card  4 .  
      According to the embodiment, as apparent from the above, in case where there is page title data on each page of a document, the user can automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds.  
      In the embodiment, the order of acquiring a document image G 1  and a handwritten information image G 2  and the timing of acquiring the document image G 1  can be changed as needed as per the first and second embodiments.  
      In case where the projector  1  cannot acquire page title data from the document image G 1  in the above-described process (NO in step SD 8 ), only the handwritten information image G 2  is recorded in the memory card  4  in the subsequent step SD 5  in the embodiment. In that case, however, the projector  1  may record the document image G 1  in place of the page title which could not be acquired and the handwritten information image G 2  as a set as per the first embodiment. In this case, the PC  2  displays the handwritten information image G 2  at the time of pasting the handwritten information image G 2  to the page designated by, for example, the user&#39;s manual work (step SE 5 ). This can allow the user to recognize to which one of pages of the document which do not have page titles the handwritten information image G 2  corresponds.  
      In the embodiment, as in the second embodiment, the system may take such a structure as not to acquire the header information of a document from the PC  2 . In this case, the processes in steps SD 2  to SD 4  in the routine shown in  FIG. 10  should be omitted. In case where the header information of a document is not acquired from the PC  2 , for example, the projector  1  records a set of an associated handwritten information image G 2  and page title or plural sets of associated handwritten information images G 2  and page titles in the memory card  4  by the same procedures as done in the first embodiment. Thereafter, the projector  1  may perform the processes of steps SD 6  to SD 8  and SD 5  at a time in order to meet the user&#39;s request.  
      In the embodiment, the projector  1  records the acquired document image G 1  and page title in the memory card  4 . However, the system structure may be modified in such a way that the projector  1  outputs document images G 1  and page titles to the PC  2  via the USB cable  31  one after another and the PC  2  stores them in the memory device  23  or so. Further, the system structure may be modified in such a way that the projector  1  outputs the document image G 1  and handwritten information image G 2 , acquired in step SD 1 , directly to the PC  2  and the PC  2  performs a process concerning acquisition of a page title, which is done by the projector  1  in the second embodiment, before the above-described image pasting routine.  
      The projector  1  may have functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, as per the first embodiment. In this case, the projector  1  may be allowed to perform the above-described image pasting routine by the PC  2  in accordance with a predetermined operation by a user or every time an image pickup operation is performed by the user.  
     Fourth Embodiment  
      The fourth embodiment of the invention is described next. This embodiment is designed in such a way as to acquire a document by obtaining the correlation between patterns of both a document image G 1  and the original document using the document image G 1  stored in the memory card as index information.  
      The projector  1  records a set of an associated document image G 1  and handwritten information image G 2  or plural sets of associated document images G 1  and handwritten information images G 2  in the memory card  4  by the procedures explained referring to  FIG. 3 . When a command to execute an image pasting routine is selected after the memory card  4  having both images G 1  and G 2  recorded there in is loaded, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 13 . It is also premised here that a document to be processed is designed beforehand by a user.  
      Based on one page of data of a document stored in the memory device  23 , the PC  2  generates image data of its display image (step SF 1 ).  
      With the generated image data as a standard pattern (template), the PC  2  executes pattern matching on all the document images G 1  stored in the memory card  4  (step SF 2 ). For instance, the PC  2  executes pattern matching to check the correlation between two images on the image data level by moving the standard pattern while placing it over each document image G 1 .  
      The PC  2  determines whether or not there is a document image G 1  whose pattern has a match (step SF 3 ).  
      When there is a document image G 1  whose pattern has a match (YES in step SF 3 ), the PC  2  acquires a handwritten information image G 2  corresponding to the pattern-matched document image G 1  from the memory card  4 . The PC  2  pastes the handwritten information image G 2  acquired from the memory card  4  to the document page from which the standard pattern has been originated (step SF 4 ).  
      The PC  2  determines whether the matching process for all the document pages has been completed or not (step SF 5 ). When it is determined that the matching process for all the document pages has not been completed (NO in step SF 5 ), the PC  2  repeats the processes of steps SF 1  to SF 4 .  
      When it is determined that the matching process for all the document pages has been completed after repeating the processes of steps SF 1  to SF 4  (YES in step SF 5 ), the PC  2  determines whether or not there is any document image G 1  which has not matched with any page in pattern matching (step SF 6 ).  
      When it is determined that there is no document image G 1  which has not matched with any page in pattern matching (NO in step SF 6 ), the PC  2  completes the process as it is.  
      Even when it is determined that there is a single document image G 1  (or there are plural document images G 1 ) which has not matched with any page in pattern matching (YES in step SF 6 ), the PC  2  carries out manual pasting by a user on each handwritten information image G 2  recorded in the memory card  4  in association with each document image G 1 . That is, the PC  2  causes the user to designate a corresponding page, pastes the handwritten information image G 2  to the designated page (step SF 7 ) and then terminates the process.  
      According to the embodiment, therefore, the user can automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds.  
      In the embodiment, the order of acquiring a document image G 1  and a handwritten information image G 2  and the timing of acquiring the document image G 1  can be changed as needed as per the first to third embodiments.  
      The foregoing description of the embodiment has discussed the process in which the projector  1  records the acquired document image G 1  and handwritten information image G 2  in the memory card  4 . However, the system structure may be modified in such a way that the projector  1  and the PC  2  are connected together by the USB cable  31 , the projector  1  outputs document images G 1  and handwritten information images G 2  to the PC  2  via the USB cable  31  one after another and the PC  2  stores them in the memory device  23  or so, as per the second and third embodiments. Further, the PC  2  may execute the above-described image pasting routine in real time. In this case, image data should be generated beforehand for every page of the document and the associated document image G 1  and handwritten information image G 2  sent from the projector  1  should be temporarily stored in the RAM  13  or so. Then, the PC  2  should perform pattern matching on image data of every page with the document image G 1  as a standard pattern and should perform a process of pasting the handwritten information image G 2  to the document page from which the pattern-matched image data has been originated.  
      In case where the projector  1  has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, as per the first embodiment, the projector  1  may be allowed to perform the above-described image pasting routine by the PC  2  in accordance with a predetermined operation by a user or every time an image pickup operation is performed by the user.  
     Fifth Embodiment  
      The fifth embodiment of the invention is discussed next.  
      An image pickup apparatus according to the fifth embodiment is designed in such a way as to convert document information to a bar cord and combine the converted bar code with a document image.  
      The projection system of the fifth embodiment is the projection system of the first embodiment shown in  FIG. 1  in which a program for executing operations to be discussed later is stored in the memory device  23  of the PC  2 .  
      The operations of the projector  1  and PC  2  are discussed below.  
      During projection of a document, the projector  1  and PC  2  operate according to a flowchart shown in  FIG. 14 .  
      The PC  2  reads data of a document, designated by a user operating the input device  24 , from the memory device  23  (step SG 1 ).  
      The PC  2  acquires document information included in the read data (step SG 2 ). The document information includes a folder name indicating where data is stored, a file name and a page number. The page number indicates a page of a document to be displayed then, and is “1” at first.  
      Next, the PC  2  converts the acquired document information to a two-dimensional bar code which is two-dimensional information (step SG 3 ).  
      The PC  2  combines the converted two-dimensional bar code to a predetermined location of a document page as display image data (step SG 4 ).  
      Thereafter, the PC  2  displays the combined image data on the display device  25  and outputs it to the projector  1  via the RGB cable  3  (step SG 5 ).  
      The PC  2  determines whether a page has been switched or not (step SG 6 ).  
      When it is determined that a page has been switched (YES in step SG 6 ), the PC  2  executes the processes of steps SG 2  to SG 5  again.  
      During the execution, the projector  1  projects a display image as shown in  FIG. 15 , based on image data output from the PC  2 , on the screen S. Along with the projection, the projector  1  performs an image pickup process according to the image pickup operation done by the user, and records the picked-up image in a document-displayed state, i.e., a document image G 3  having a two-dimensional bar code B at the lower left corner as shown in  FIG. 15  and handwritten information image G 2  as a set in the memory card  4  loaded into the main body (steps SA 1  to SA 4 ), as per the first embodiment.  
      When it is determined that a page has not been switched (NO in step SG 6 ), the PC  2  terminates this process.  
      In this manner, a set of an associated document image G 3  and handwritten information image G 2  or plural sets of associated document images G 3  and handwritten information images G 2  are recorded in the memory card  4 .  
      When the memory card  4  having the document image G 3  and handwritten information image G 2  recorded therein is loaded into the PC  2  and a command to execute an image pasting routine is selected, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 16 .  
      The PC  2  first reads the document image G 3  from the memory card  4  (step SG 11 ).  
      The PC  2  acquires the aforementioned document information from the two-dimensional bar code B included in the read document image G 3  (step SG 12 ).  
      Subsequently, the PC  2  accesses a file of a document indicated by the acquired document information and reads the file of the document (step SG 13 ).  
      The PC  2  pastes the handwritten information image G 2  to the page corresponding to the page number included in the document information and records that data (step SG 14 ). Then, the PC  2  repeats the above-described sequence of processes in order by the number of document images G 3  and handwritten information images G 2  recorded in the memory card  4 .  
      According to the embodiment, therefore, the user can automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds. What is more, there is a merit such that information other than document information can be assembled into the two-dimensional bar code B as needed.  
      The foregoing description of the embodiment has illustrated an example where the two-dimensional bar code B is used as two-dimensional information of the invention. The two-dimensional information is not however limited to this bar code, but other two-dimensional information which has a relatively small area, such as an intact code, may be combined at a predetermined location of a document and displayed in that fashion.  
      In the embodiment, the order of acquiring a document image G 1  and a handwritten information image G 2  and the timing of acquiring the document image G 1  can be changed as needed as per the first to fourth embodiments.  
      The projector  1  and the PC  2  may be connected together by the USB cable  31 , so that the projector  1  outputs document images G 3  and handwritten information images G 2  to the PC  2  via the USB cable  31  one after another and the PC  2  stores them in the memory device  23  or so, as per the second and third embodiments, for example.  
      In case where the projector  1  has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, as per the first embodiment, the projector  1  can perform the above-described image pasting routine by the PC  2  in accordance with a predetermined operation by a user.  
     Sixth Embodiment  
      The sixth embodiment of the invention is discussed next.  
      An image pickup apparatus according to the sixth embodiment is so designed as to store display history information, such as the display time or so of each page.  
      The projection system of the sixth embodiment is the projection system of the first embodiment shown in  FIG. 1  in which the projector  1  and the PC  2  respectively have wave clocks  20  and  29  as shown in  FIG. 17 . The wave clocks  20  and  29  serve to acquire a display start time and a display end time for a document page and is used to acquire the same reference time.  
      The PC  2  of the projection apparatus according to the sixth embodiment generates display history information as shown in  FIG. 19 . The display history information is used to retrieve a handwritten information image G 2  and is comprised of individual data of a management ID, a document name, a page number, a start/end flag, a start time and end time. The management ID, which is used to identify a displayed page, is given for each page displayed. The document name is the name of a document and is comprised of a folder name and a file name. The page number indicates a page of a document. The start/end flag is data showing display in progress when “0” and showing the end of display when “1”. The start time and end time respectively indicate the time when the display of a document page has started and the time when the display of a document page has ended.  
      The operations of the projector  1  and PC  2  according to the invention are discussed below.  
      During projection of a document, the projector  1  and PC  2  operate according to a flowchart shown in  FIG. 18 .  
      The PC  2  reads data of a document, designated by a user operating the input device  24 , from the memory device  23  (step SH 1 ).  
      The PC  2  displays the image data of a predetermined page of the read document on the display device  25  and outputs it to the projector  1  via the RGB cable  3  (step SH 2 ).  
      Subsequently, the PC  2  acquires the present time indicated by the wave clock  29  (step SH 3 ).  
      The PC  2  stores the display start time of the document page, the document name and the page number in the RAM  22  (step SH 4 ).  
      The PC  2  determines whether or not a display end operation, i.e., a page switching operation or a document display end operation has been performed (step SH 5 ).  
      When it is determined that the display end operation has not been performed (NO in step SH 5 ), the PC  2  stands by until the display end operation is executed.  
      When it is determined that the display end operation has been performed (YES in step SH 5 ), the PC  2  acquires the present time indicated by the wave clock  29  again (step SH 6 ).  
      The PC  2  stores that time as the display end time for the document page in the RAM  22  (step SH 7 ).  
      The PC  2  determines whether or not the display end operation for the document has been performed (step SH 8 ).  
      When it is determined that the display end operation is not the document display end operation (NO in step SH 8 ), the PC  2  repeats the sequence of processes of steps SH 2  to SH 7 . Accordingly, display history information  100  as shown in  FIG. 19  is stored in the RAM  22  in order.  
      When it is determined that the display end operation is the document display end operation (YES in step SH 8 ), the PC  2  stores the display history information  100  stored then in the RAM  22  in the memory device  23  (step SH 9 ).  
      During the above operation, the projector  1  projects a display image, based on the image data output from the PC  2 , on the screen S (step SI 1 ).  
      Thereafter, when the user performs an image pickup operation, the projector  1  stops projecting document information and picks up the image of the screen S in a non-projection state where only white light is irradiated onto the screen S, thereby acquiring a handwritten information image G 2  (see  FIG. 4B ) (step SI 2 ). It is premised here that handwritten information is directly written on the screen S.  
      The projector  1  then acquires the present time indicated by the wave clock  20  (step SI 3 ).  
      The projector  1  stores that time data and data of the handwritten information image G 2  in the memory card  4  loaded into the main body (step SI 4 ). That is, the projector  1  generates an image file in which the time acquired in step SI 4  is stored as the image pickup time and records the generated image file into the memory card  4 . The projector  1  and the PC  2  repeat the above-described operation every time a document page or a document to be projected is changed.  
      One handwritten information image G 2  or plural handwritten information images G 2  are recorded in the memory card  4  in this manner.  
      When the memory card  4  in this state is loaded and then a command to execute an image pasting routine is selected, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 20 .  
      The PC  2  first reads the display history information  100 , stored by the procedures explained above, from the memory device  23  (step SH 11 ).  
      The PC  2  acquires the start time and the end time between which the first page of the document was displayed (step SH 12 ).  
      Then, the PC  2  retrieves a handwritten information image G 2  picked up within the time from the memory card  4  (step SH 13 ).  
      The PC  2  pastes the retrieved handwritten information image G 2  to the first page of the document and records the data in the memory device  23  (step SH 14 ). The PC  2  performs the processes of steps SH 11  to SH 14  for other pages of the document. Note however that when a handwritten information image G 2  picked up in the display time has not been retrieved, the PC  2  skips the process of step SH 14 .  
      According to the embodiment, therefore, the user can also automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds. As the image pickup time for the handwritten information image G 2  and the display time of each page of a document which is recorded in the display history information  100  are acquired by the wave clocks  20  and  29  and are adjusted by the same reference, it is possible to accurately associate handwritten information with each page of the document. What is more, unlike in the first to fifth embodiments, the handwritten information image G 2  is the only image which is acquired while the projector  1  performs image projection and recorded in the memory card  4  so that the memory card  4  can be used effectively.  
      In the sixth embodiment, the projector  1  and the PC  2  may be connected together by the USB cable  31 , so that the projector  1  outputs handwritten information images G 2  to the PC  2  one after another and the PC  2  stores the handwritten information images G 2  in the memory device  23  or so, as per the second and third embodiments, for example.  
      In case where the projector  1  has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, as per the first embodiment, the projector  1  can perform the above-described image pasting routine by the PC  2  in accordance with a predetermined operation by a user. In this case, even if the wave clock  20  is an ordinary clock whose time is adjusted by a user, it is possible to accurately associate handwritten information with each page of the document as in the sixth embodiment.  
     Seventh Embodiment  
      The seventh embodiment of the invention is discussed next. An image pickup apparatus according to the seventh embodiment is so designed as to acquire a document by using management information which manages the locations for a document, a document image and a handwritten information image as index information.  
       FIG. 21  is a structural diagram of a projection system illustrating the embodiment.  
      This projection system, like that of the second embodiment shown in  FIG. 5 , comprises a projector  1  and PC  2  connected together by an RGB cable  3  and USB cable  31 . It is to be noted however that the card interface circuits  17  and  26  shown in  FIG. 21  are omitted from the projector  1  and PC  2  of this embodiment.  
      The memory device  23  of the PC  2  includes an image data memory section  23   a  and a document data memory section  23   b . The image data memory section  23   a  stores image data. The document data memory section  23   b  stores document data. The memory device  23  stores image management information  200  as shown in  FIG. 24 . The image management information  200  includes a management ID, a document name, a page number and an image name. The management ID is information for specifying document data and image data. The document name is a name to designate document data. The document name is comprised of a memory location in the memory device  23  where document data is stored and a file name. In the example shown in  FIG. 24 , “C:\AAA\BBB\” indicates the path to the memory location to store document data by a folder name and “CCC.ppt” indicates the file name of the document data.  
      The page number indicates the page number of a document page to be displayed and is “1” at first. In the example shown in  FIG. 24 , the page number is “5”. The document information is comprised of a folder name which is the storage location for data, a file name and a page number. In the example shown in  FIG. 24 , the folder name “BBB”, the file name “CCC.ppt” and the page number “5” are the document information of this document.  
      The image name is a name to designate image data. The image name is comprised of a memory location in the memory device  23  where image data is stored and a file name. In the example shown in  FIG. 24 , “C:\AAA\DDD\” indicates the path to the memory location to store image data by a folder name and “01.JPG” indicates the file name of the image data.  
      The operations of the projector  1  and the PC  2  according to the invention are discussed below.  
      During projection of a document, the PC  2  and the projector  1  execute an image management information generating routine according to a flowchart shown in  FIG. 23 .  
      The PC  2  reads data of a document, designated by a user operating the input device  24 , from the memory device  23 , displays the image data of a predetermined page on the display device  25  and outputs it to the projector  1  via the RGB cable  3  (step SJ 1 ).  
      Meanwhile, the projector  1  projects a display image, based on the image data output from the PC  2 , on the screen S (step SK 1 ).  
      Thereafter, when the user performs an image pickup operation, the projector  1  stops image projection, irradiates white light alone onto the screen S, and picks up the image of the screen S in a non-projection state. Then, the projector  1  acquires a handwritten information image G 2  (see  FIG. 4B ) (step SK 2 ). It is premised here that handwritten information is directly written on the screen S.  
      The projector  1  outputs data of the handwritten information image G 2  to the PC  2  via the USB cable  31  (step SK 3 ).  
      The above-described operation is repeated every time a document page or a document to be projected is changed.  
      As image data is output from the projector  1 , the PC  2  stores the input image data in the RAM  22  by an interruption process (step SJ 2 ).  
      Further, the PC  2  stores document information included in the original data of the document displayed then in the RAM  22  in association with the image data of the handwritten information image G 2  (step SJ 3 ).  
      Thereafter, the PC  2  stores the image data of the handwritten information image G 2  stored in the RAM  22  into the image data memory section  23   a , designates an image name and stores the image management information  200  as shown in  FIG. 24  into the memory device  23  (step SJ 4 ).  
      Then, the PC  2  repeats the sequence of processes and switches a page to be displayed and output when there is a page switching operation during the repetition.  
      As the image management information  200  concerning one page or plural pages is recorded in the memory card  4  in this manner and a command which causes the PC  2  to execute an image pasting routine is selected by the user, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 25 .  
      The PC  2  reads the image management information  200  from the memory device  23  (step SJ 11 ).  
      The PC  2  reads image data indicated in association with each management ID of the image management information  200 , i.e., image data of the handwritten information image G 2 , from the memory device  23 . The PC  2  pastes the read handwritten information image G 2  to a document page with a page number corresponding to the image name and records the data of the document pasted with the handwritten information image G 2  into the memory device  23  (step SJ 12 ).  
      According to the embodiment, therefore, the user can also automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds. As the handwritten information image G 2  is the only image which is acquired while the projector  1  performs image projection and recorded in the memory card  4 , the memory card  4  can be used effectively, as per the sixth embodiment.  
      In case where, unlike in the seventh embodiment, the projector  1  has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, the projector  1  may be allowed to perform all the operations of the PC  2  described above.  
     Eighth Embodiment  
      The eighth embodiment of the invention is discussed next. This embodiment is the projection system of the second embodiment as shown in  FIGS. 5 and 6  which is so modified as to affix index related information to the property of a handwritten information image and record the data in the memory card.  
      As an image projected on the screen S is picked up, the projector  1  according to the eighth embodiment generates a property (attribute)  300  of image data as shown in  FIG. 27  acquired by image pickup. The property  300  is comprised of general information and image information. The general information includes information about image data acquired by image pickup, i.e., a file name, size, date of generation and date of update. The projector  1  adds a target file and a target page as added data to the property  300 .  
      The target file indicates a document to which an acquired handwritten information image G 2  is to be added, and is comprised of a folder name where document data is stored and a file name. In the example shown in  FIG. 27 , the folder name of the target file is “C:\AAA\BBB\” and the file name is “CCC.ppt”.  
      The target page indicates a page of a document to which the acquired handwritten information image G 2  is to be added. In the example shown in  FIG. 27 , the target page is page “1”.  
      During projection of a document, as the PC  2  outputs document information and the RAM  13  stores the document information output from the PC  2 , the projector  1  obtains data on the target file and the document page from the document information stored in the RAM  13 , adds the data to the property  300  and stores the property  300  in the memory card  4 .  
      The operations of the projector  1  and PC  2  are discussed below.  
      During projection of a document, the PC  2  and the projector  1  operate according to a flowchart shown in  FIG. 25 .  
      As a user designates a document by operating the input device  24 , the PC  2  reads data of the designated document from the memory device  23 , displays the image data of a predetermined page on the display device  25  and outputs it to the projector  1  via the RGB cable  3  (step SL 1 ).  
      Further, the PC  2  sends document information included in the original data of the then displayed document, i.e., a folder name where data is stored, a file name and a page number, to the projector  1  via the USB cable  31  (step SL 2 ).  
      During the above operation, the projector  1  projects a display image, based on the image data output from the PC  2 , on the screen S (step SM 1 ).  
      Further, the projector  1  acquires the document information output from the PC  2  and stores it in the RAM  13  (step SM 2 ).  
      Thereafter, when the user performs an image pickup operation, the projector  1  stops projecting document information and picks up the image of the screen S in a non-projection state where only white light is irradiated onto the screen S, thereby acquiring a handwritten information image G 2  (see  FIG. 4B ) (step SM 3 ). It is premised here that handwritten information is directly written on the screen S.  
      Then, the projector  1  adds the document information stored in the RAM  13  to the property of the image data acquired by image pickup and records the image file in the memory card  4  loaded into the main body (step SM 4 ). The above-described operation is repeated every time a document page or a document to be projected is changed.  
      When the memory card  4  where one handwritten information image G 2  or plural handwritten information images G 2  are recorded is loaded and then a command to execute an image pasting routine is selected by a user, the PC  2  executes the image pasting routine according to a flowchart illustrated in  FIG. 28 .  
      The PC  2  first reads the data (image file) of a handwritten information image G 2  from the memory card  4  (step SN 1 ).  
      The PC  2  acquires data on a target file and a target page from the property of the data of the read handwritten information image G 2  (step SN 2 ).  
      Subsequently, the PC  2  reads a document corresponding to the target file from the memory device  23  (step SN 3 ).  
      The PC  2  pastes the handwritten information image G 2  to the document page corresponding to the target page and records the data of that document in the memory device  23  (step SN 4 ). Then, the above-described sequence of processes is repeated by the number of handwritten information images G 2  recorded in the memory card  4 .  
      According to the embodiment, therefore, the user can also automatically paste saved handwritten information to a corresponding page and use it without a need to check himself or herself to which page of the document the handwritten information saved at the time of projecting the document corresponds. As the handwritten information image G 2  is the only image which is acquired while the projector  1  performs image projection and recorded in the memory card  4 , the memory card  4  can be used effectively, as per the sixth and seventh embodiments.  
      What is more, as a target file and a target page to the property of the handwritten information image G 2 , it is possible to know a document page corresponding to the handwritten information image G 2  directly from the handwritten information image G 2 . This brings about a merit of further improving the usability.  
      Although the projector  1  records an acquired handwritten information image G 2  in the memory card  4  in this embodiment, a modification may be made in such a way that the projector  1  outputs handwritten information images G 2  one after another via the USB cable  31  to the PC  2  which in turns stores the handwritten information images G 2  in the memory device  23  or so.  
      In case where the projector  1  has functions of reading original data of a document recorded in the memory card  4  and projects the display image of the document onto the screen S based on the read data, the projector  1  may be allowed to perform the image pasting routine.  
      The foregoing descriptions of the second to eighth embodiments have been given mainly of the case where the PC  2  has a function of automatically pasting a handwritten information image G 2  to a predetermined page of a corresponding document. Instead, the PC  2  may be given a function of simply informing a user of a page corresponding to a handwritten information image G 2  by an arbitrary method, such as displaying a page number or a page title, in each embodiment. This case also provides such an effect that when using handwritten information directly written on the screen S, a user can easily know in which projection of which document the handwritten information was written.  
      Further, the foregoing descriptions of the first to eighth embodiments have been given mainly of the example where the invention is worked out by using the projector  1  incorporating the digital camera section  16 . The invention can however be worked out as the structure in which a separate digital camera is externally mounted onto the projector that has, for example, only a document projecting function. In this case, the projector  1  sends a predetermined shutter signal to the digital camera, as needed, to control the image pickup operation of the digital camera.  
      In the above-described embodiments, the CPU  21  generates a combined image by pasting a handwritten information image G 2  to a document image. However, the projector  1  can acquire a document image G 1  already handwritten as shown in  FIG. 4A  from the memory card  4  and project it directly.  
      What is to be recorded on the screen S is not limited to handwritten information but includes, for example, a writing or so pasted on the screen S.  
      The foregoing descriptions of the embodiments have been given of the example where the PC  2  acquires a document from a handwritten information image G 2 . But, the PC  2  can acquire a handwritten information image G 2  from a document. In this case, index information indicating the storage location for a handwritten information image G 2  corresponding to a document is stored in the file of the document.  
      Various embodiments and changes may be made thereunto without departing from the broad spirit and scope of the invention. The above-described embodiments are intended to illustrate the present invention, not to limit the scope of the present invention. The scope of the present invention is shown by the attached claims rather than the embodiments. Various modifications made within the meaning of an equivalent of the claims of the invention and within the claims are to be regarded to be in the scope of the present invention.  
      This application is based on Japanese Patent Application No. 2002-366005 filed on Dec. 18, 2002 and including specification, claims, drawings and summary. The disclosure of the above Japanese Patent-Application is incorporated herein by reference in its entirety.