JP2005115702A - Document display device, program, and method for displaying document - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extract and display information for a general understanding of the content of an electronic document. <P>SOLUTION: For each page of a document consisting of a plurality of pages, a structure data creation means 24 obtains layout information showing the layout of components that constitute each page, to create structure data showing a hierarchial structure on the layout between areas occupied by the components on each page. Next, a variation calculating means 25 calculates a variation showing the degree of variation in the hierarchial structure between a page of interest and a page in front of the page of interest in ascending or descending order of the pages. The variation calculated by the variation calculating means 25 is compared with a preset threshold, and if the variation is equal to or greater than the threshold, a display means 27 displays the page of interest. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for extracting and displaying information desired by a user from an electronic document.

  A document editor having a preview function for displaying a reduced image of a document in a page order on a personal computer display is provided. The preview function is intended to roughly grasp the contents of the electronic document. However, when a large number of reduced images are displayed side by side, the layout of the entire document can be confirmed, but it is difficult to read the characters written on each page. On the other hand, if the display magnification is increased in order to interpret the characters, the number of pages to be displayed is reduced, and it takes time to scroll the screen until the entire document is viewed. Further, when the area of the display screen is small or the number of pages of a document is large as in the case of a portable information terminal, a large number of scroll operations or page feeds are required, so that work efficiency is lowered.

By the way, various techniques have been proposed for the purpose of roughly grasping the contents of an electronic document (for example, Patent Document 1). In the technique described in Patent Document 1, an index called “appearance degree” indicating the degree of information reduction is introduced, and the appearance degree determined by the user to be optimal is set, thereby contributing to a rough grasp of the contents of the electronic document. Only the information to be displayed is displayed. Here, based on the premise that information representing the characteristics of the document is described using characters of a size or font different from normal, for example, in a document in which full-width characters and double-width characters are mixed, double-width characters are displayed as they are, For full-width characters, only the circumscribed rectangle is displayed. Alternatively, the character modification such as underline is deleted and displayed. This speeds up the display and provides only the information that contributes to the general grasp to the user, thereby reducing the burden on the user.
JP-A-8-212444

However, since the technique described in Patent Document 1 displays all pages regardless of the presence or absence of characters described in a different size or font, it does not lead to a significant improvement in work efficiency. In addition, since the criterion for determining whether or not to display characters is limited to the characteristics of the characters, the user can obtain only information limited thereto.
The present invention has been made based on the above-described background, and an object thereof is to provide a technique capable of extracting information for roughly grasping the contents of an electronic document and displaying the information.

  In order to solve the above-described problem, the present invention acquires, for each page of a document composed of a plurality of pages, layout information representing the layout of the constituent elements constituting the page, and each constituent element occupies the page. The degree of change in the hierarchical structure between the structural data generating means for generating the structural data representing the hierarchical structure on the layout between the areas, the target page, and the page immediately before the target page in the ascending or descending order of the page The change amount calculating means for calculating the change amount representing the change amount and the change amount obtained by the change amount calculating means are compared with a predetermined threshold value, and when the change amount is equal to or greater than the threshold value, Provided is a document display device having display means for displaying.

  Further, according to the present invention, the computer apparatus obtains layout information representing the layout of the constituent elements constituting the page for each page of the document including a plurality of pages, and between the areas occupied by the constituent elements in the page. A change that represents the degree of change in the hierarchical structure between the structural data generating means for generating the structural data representing the hierarchical structure on the layout, the page of interest, and the page immediately before the page of interest in the ascending or descending order of the page A change amount calculating means for calculating an amount, a display for comparing the amount of change obtained by the change amount calculating means with a predetermined threshold and displaying the page of interest when the amount of change is equal to or greater than the threshold A program for functioning as a means is provided.

  Further, the present invention acquires layout information representing the layout of the constituent elements constituting the page for each page of a document composed of a plurality of pages, and the layout hierarchy between the regions occupied by the constituent elements on the page. A structure data generation step for generating structure data representing a structure, a change amount indicating a degree of change in the hierarchical structure between the page of interest and a page immediately before the page of interest in the ascending or descending order of the page. A change amount calculating step; and a display step of comparing the change amount obtained by the change amount calculating means with a predetermined threshold value and displaying the page of interest when the change amount is equal to or greater than the threshold value. Provide a document display method.

  According to the present invention, for each page of a document composed of a plurality of pages, the structure data generation unit obtains layout information representing the layout of the constituent elements constituting the page, and the area occupied by the constituent elements in the page Generate structure data that represents the hierarchical structure of the layout. Next, the change amount calculation means calculates a change amount indicating the degree of change in the hierarchical structure between the page of interest and the page immediately before the page of interest in the ascending or descending order of the page. Then, the display unit compares the change amount obtained by the change amount calculation unit with a predetermined threshold value, and displays the page of interest when the change amount is equal to or greater than the threshold value.

  According to the present invention, it is possible to extract information for roughly grasping the contents of an electronic document and display the information.

When a human takes an unknown document and wants to know roughly what is written in the document, it is often the case when a page with visual features appears quickly by turning the page quickly Keep an eye on the page. Examples of visually distinctive pages include pages that include a table of contents, chapter / section / section headings, and charts. However, even if it is such a page, if the page of the same layout continues over many pages, a human will turn a page without paying attention to this. In other words, human beings will notice a page whose layout has changed from the previous page.
The present invention provides an apparatus for quantifying a layout change between pages of a document composed of a plurality of pages, and extracting and displaying a page having a large layout change amount with respect to the previous page.

[Constitution]
FIG. 1 is a diagram illustrating a hardware configuration of the document display device 10. A program 10P is written in a ROM (Read Only Memory) 102. When a power (not shown) is turned on to the document display device 10, a CPU (Central Processing Unit) 101 reads a program 10P written in the ROM 102, and uses the RAM (Random Access Memory) 103 as a work area to store the program 10P. Execute. When the CPU 101 executes the program 10P, the module group shown in FIG. 11 is virtually formed in the document display device 10. The program 10P may be stored in an external device, and the program 10P may be downloaded via the network 113 and stored in the ROM 102.

The document storage unit 117 is a hard disk drive that stores document data or image data representing an image of a document. The document processing unit 118 reads out document data or image data stored in the document storage unit 117 under the control of the CPU 101, and performs various processes. The CPU 101, ROM 102, RAM 103, document storage unit 117, and document processing unit 118 are connected to the bus 115.
The display unit 105 is a CRT (Cathode Ray Tube) or a liquid crystal panel. The operation unit 107 is a pointing device (mouse or digitizer) and a keyboard. The scanner 109 optically reads a document and outputs an image signal. The printer 111 is an electrophotographic printer or an inkjet printer. The display unit 105, the operation unit 107, the scanner 109, and the printer 111 are connected to the bus 116 via the interfaces 106, 108, 110, and 112, respectively. The bus 115 and the bus 116 are connected by the bus bridge 104. The bus 116 is connected to the network 113 via the interface 114, and mediates communication between the document display device 10 and an external device.

Next, a module group virtually formed in the document display device 10 when the CPU 101 executes the program 10P will be described with reference to FIG.
The document acquisition unit 21 is a unit that acquires document data including document layout information or image data representing an image of a document. Here, the document data refers to document data created using an application program such as a word processor, or document data described in a page description language. In addition to character information, these document data include information representing graphic images, information representing ruled lines of the table, and information representing their layout within each page. The image data representing the image of the document is image data generated by scanning the document using an image input device such as the scanner 109. The document data and the image data may be stored in the document storage unit 117 in advance, or may be received by the document display device 10 via the network 113 from an external device.

The first acquisition means 22 is means for extracting layout information representing the layout of the constituent elements constituting each page of the document from the document data. A component is a sentence, a figure, a table, or the like. In the present embodiment, an area in which sentences are spatially continuous is referred to as a sentence area. An area occupied by the figure is called a figure area, and an area occupied by the table is called a table area.
The second acquisition unit 23 is a unit that acquires the layout information of the document by analyzing the image of the document represented by the image data. The image data is composed of pixel values obtained by scanning the document with the scanner 109, and does not have layout information that the document data contains. Therefore, the second acquisition unit 23 obtains the layout information of the document represented by the image using a known layout analysis technique. The layout analysis is performed using a technique described in, for example, Japanese Patent Laid-Open No. 2000-90194. In this technique, it is determined whether a sentence included in a document image is vertical writing or horizontal writing, and a boundary for dividing the document is set according to the determination result. Further, the projection distribution of the pixels constituting the document image is calculated, and the division boundary is set using a section having a frequency that does not satisfy a predetermined threshold.
In this way, the first acquisition unit 22 acquires the layout information of the document, and recognizes each page as a set of a text area, a figure area, and a table area.

  The structure data generation unit 24 obtains layout information representing the layout of the constituent elements constituting the page for each page of the document composed of a plurality of pages, and on the layout between the regions occupied by the constituent elements on the page. This is means for generating structure data representing a hierarchical structure. Here, when the document data is acquired by the document acquisition unit 21, the structure data generation unit 24 acquires the layout information using the first acquisition unit 22. On the other hand, when image data is acquired by the document acquisition unit 21, layout information is acquired using the second acquisition unit 23. As shown in FIG. 5, the structure data in the present embodiment has a tree structure with each page as a root.

The change amount calculating means 25 is a means for calculating a change amount indicating the degree of change in the hierarchical structure between the page of interest and the previous page. The change amount is calculated in both the ascending and descending order of the page. The change amount storage unit 26 is a unit that stores the change amount obtained by the change amount calculating unit 25 in association with the page of interest.
The display unit 27 is a unit that compares the amount of change of the page of interest with a predetermined threshold, and displays the page of interest when the amount of change is greater than or equal to the threshold. Here, the display unit 27 extracts pages whose change amount stored in the change amount storage unit 26 is equal to or greater than the threshold value, and displays the images of the extracted pages in the ascending or descending order of the pages.
The processing performed by the structure data generation unit 24, the change amount calculation unit 25, the change amount storage unit 26, and the display unit 27 will be described in detail in the description of the operation.

[Operation]
The operation of the document display device 10 having the above configuration will be described. However, since the document display device 10 is a device that operates by using software as hardware, in the following description, the subject of operation is hardware, not a virtually formed module.
Here, an example of a document will be described. FIG. 4 is a diagram illustrating an example of a document to be processed by the document display device 10. This example is an example of a document (for example, a paper) created in accordance with a format based on horizontal writing two columns.

  It can be seen that the layout of the document is different between the first page and the second page. In the first page, first, one line of the title is written at the top with a large character size, and there are six lines of abstracts below. Below that, the main text is written in two columns and 13 lines on each of the left and right columns. The second page is described in two columns as in the case of the first page, and pages with the same layout continue to the L-2 page. In the (L-1) th page, a graph is inserted above the page. The L-th page has the same layout as the second page, and this layout page continues to the M-3th page. On the M-2 page, a car figure is inserted at the bottom of the right column, and on the M-1 page, a table is written on the entire page. The M page has the same layout as the second page, and this layout continues to the (N-1) th page. On the Nth page, the photograph of the author's face and an introductory article are written on the right side.

FIG. 2 is a diagram illustrating a flow of processing performed by the CPU 101 executing the program 10P. Here, it is assumed that the document display apparatus 10 is turned on and the CPU 101 is executing the program 10P.
First, when the user operates the operation unit 107, an instruction for designating a document (document data or image data) to be displayed on the document display device 10 is input (step S01). The document designated here may be a document stored in the document storage unit 117 in advance, or a document stored in an external device may be received via the network 113. Next, the CPU 101 reads out a document designated by the user from the document storage unit 117 or receives it from an external device via the network 113 and develops the data on the RAM 103 (step S02). It is determined whether or not structure data has been created for (Step S03). If the structure data has been created (step S03: YES), the process proceeds to document display processing (step S05). If the structure data has not been created (step S03: NO), the process proceeds to the structure data creation process (step S04). Details of the processes in step S04 and step S05 will be described later.

  FIG. 3 is a diagram showing a detailed flow of the structure data creation process (step S04). First, the CPU 101 sets the first page of the document expanded on the RAM 103 as the attention page (step S401). Next, the CPU 101 determines whether or not the acquired data is image data input by an image input device such as the scanner 109 (step S402). When it is determined that the acquired data is image data (step S402). : YES), a document layout analysis process is performed to obtain layout information (S403). On the other hand, if it is determined in step S402 that the data is not image data (step S402: NO), that is, if the acquired data is document data, a predetermined data conversion operation is performed to extract layout information. (S404).

  Next, the CPU 101 generates the structure data of the page of interest based on the layout information acquired in step S403 or step S404 (S405). As shown in FIG. 5, the structure data has a tree structure with each page as a root. The hierarchy of the tree structure is determined as follows. In the example of the first page, it is first divided into three regions in the horizontal direction, and then the lowermost region is considered to be divided into two in the vertical direction. If this is represented by a tree structure, there are two leaves and one intermediate contact in the hierarchy one level below the root, and the two leaves are associated with regions 1 and 2. There are two more leaves in the hierarchy one level below the intermediate contact, and the two leaves are associated with regions 3 and 4.

On the other hand, in the example of the (M−2) -th page, it is assumed that the right area is first divided into two areas in the vertical direction and then divided into two areas in the horizontal direction. If this is represented by a tree structure, one leaf and one intermediate contact exist in the hierarchy one level below the root, and the leaf is associated with the region 1. There are two more leaves in the hierarchy one level below the intermediate contact, and the two leaves are associated with region 2 and region 3.
Returning to the flowchart of FIG. In step S406, it is determined whether the page of interest is the second page or later. If it is the second page or later (step S406: YES), the amount of change is calculated from the structure data of the previous page and the structure data of the page of interest (step S407).

  Here, the calculation procedure of the change amount in step S407 will be described. First, the CPU 101 weights each leaf constituting the tree structure according to its hierarchy. FIG. 6 is a diagram illustrating a weighting method. Here, the hierarchy of the structure data is referred to as Level_0, Level_1, Level_2, and Level_3 in order from the top. Then, weighting is performed on the layout change. For example, Weight_1 is given when the layout changes between Level_0 and Level_1 between adjacent pages, Weight_2 is given between Level_1 and Level_2, and Weight_3 is given between Level_2 and Level_3. When there are a plurality of change events, the weight is multiplied by the number of events, and the sum of the weights for all events is defined as the change amount. Needless to say, the number of hierarchies varies depending on the layout of the document to be handled.

As an example of the amount of change calculation, consider the first and second pages (see FIG. 5). In this case, it can be regarded that the area 1 and area 2 on the first page disappeared is the second page. According to the tree structure in FIG. 6, two leaves of Level_1 on the first page are absorbed by the root (Level_0). The amount of change ΔP at this time is
ΔP = 2 × Weight_1
It is expressed.
Similarly, in the Nth page, after the area 2 of the (N-1) th page is divided into three areas, it can be considered that the three areas are further divided into two. The amount of change ΔP at this time is
ΔP = 3 × Weight_2 + (2 × Weight_3) × 3
It is expressed.

On the other hand, there is no correlation in layout between the Mth page and the M-1th page. In this case, it is considered that the two areas of the M page appear after the two areas of the (M−1) th page disappear. The amount of change ΔP at this time is
ΔP = 2 × Weight_1 + 2 × Weight_1
It becomes.
Further, as described above, since the first page can be regarded as the lowermost area divided into the left and right after the appearance of the three areas for the empty page, the change amount ΔP is ,
ΔP = 3 × Weight_1 + 2 × Weight_2
It is expressed.

In calculating the change amount, appropriate values are given to Weight_1, Weight_2, Weighr_3,. For example, when Weight_1 = 8, Weight_2 = 2, and Weight_3 = 1 are given, the change amount from the first page to the second page is 16, and the change amount from the N-1 page to the N page is 12. . FIG. 7 is a diagram showing the transition of the variation obtained in this way. Thus, the greater the layout change, the greater the amount of change.
Returning to the flowchart of FIG. After calculating the change amount, the CPU 101 determines whether the page of interest is the last page (step S408). If the page of interest is the last page (step S408: YES), the process ends. If it is not the last page (step S408: NO), the next page is set as the page of interest (S409), and the process returns to step S402.

Next, processing for displaying a page with a large change amount using the change amount obtained as described above will be described with reference to FIG. FIG. 8 is a diagram showing a detailed flow of the document display process (step S05 in FIG. 3).
First, the CPU 101 displays the first page of the document of interest developed on the RAM 103 on the display unit 105 (step S501). FIG. 10 is a diagram illustrating an example of a user interface displayed on the screen of the document display device 10. A button for switching the page to be displayed is displayed at the lower end of the screen. The fast-forward button is a button for sequentially displaying only pages with a large amount of layout change, and the forward direction and the reverse direction can be selected. The forward direction is the ascending order of pages, and the reverse direction is the descending order of pages. In the present embodiment, an event-driven display device (application program) is assumed, and when any event occurs, the CPU 101 determines whether this is an event in which the fast-forward button is pressed (S502). ). If the event is not a press of the fast-forward button (step S502: NO), document display processing corresponding to each event is executed (step S510). On the other hand, if the event is a fast-forward button press (step S502: YES), it is determined whether the event is forward or backward (step S503). In the case of the forward direction (step S503: YES), it is determined whether or not there is a change point page after the page of interest (step S504), and in the case of the reverse direction (step S503: NO), before the page of interest. It is determined whether there is a change point page (step S507).

  Here, the changing point will be described. A change point is a page with a large amount of change in layout, and can be extracted by appropriately setting a threshold of change. FIG. 9 is an example in which pages (change point pages) corresponding to change points are extracted by setting threshold values TH1 to TH3 in the transition of the change amounts shown in FIG. For example, by selecting TH1 as the change amount threshold value, only pages in which a relatively large layout change has occurred can be extracted as change point pages. On the other hand, by selecting the threshold value TH3, it is possible to extract a page in which a minute change has occurred in the layout as a change point page. This threshold value may be set for each document, or a predetermined constant value may be used. Of course, any setting by the user is also possible. For a document that has been browsed once, the threshold used at that time may be stored in the document storage unit 117, or the document display device 10 may have a learning function to select an optimum threshold. Also good.

Returning to the description of FIG. If there is a change point page after the page of interest in step S504 (step S504: YES), the CPU 101 displays the change point page on the display unit 105 (step S505). If there is no change point page after the page of interest (step S504: NO), the last page is displayed (step S506).
On the other hand, if there is a change point page before the page of interest in step S507 (step S507: YES), the CPU 101 displays the change point page on the display unit 105 (step S508). If there is no change point page before the page of interest (step S507: NO), the first page is displayed (step S509).
When the processing so far is completed, the CPU 101 performs a display prompting the user to select whether or not to end the document display (step S511). If an instruction to end document display is input (step S511: YES), the CPU 101 ends all processing. If an instruction not to end the document display is input (step S511: NO), the process returns to step S502.

As described above, according to the present invention, it is possible to quantify changes in layout between pages of a document composed of a plurality of pages, and to extract and display pages whose layout changes greatly. In other words, the act of roughly knowing what is written in the document by paying attention to a visually characteristic page is realized on the screen of the document display device. As a result, information for roughly grasping the contents of the electronic document can be extracted and displayed.
Further, since the layout information can be extracted regardless of whether the input data is document data or image data, it can correspond to data of an arbitrary format. Further, since the calculated amount of change is stored and pages whose amount of change is equal to or greater than the threshold value are displayed in order (ascending order or descending order), it is possible to efficiently grasp the contents of the document. Further, by changing the threshold value, it is possible to make fine settings such as displaying even a page with a relatively small degree of layout change.

[Modification]
The present invention is not limited to the form described above, and can be implemented in various forms. For example, the embodiment described above can be modified as follows.

  In the above-described embodiment, the amount of change is calculated for all pages, the calculated amount of change is stored in the document storage unit 117, and pages whose amount of change is equal to or greater than the threshold are sequentially displayed. It is good also as processing sequentially for every page. That is, it is possible to perform change amount calculation, comparison with a threshold value, and display / non-display processing for each page.

  In the above-described embodiment, both document data and image data can be supported. However, the present invention may be modified so as to support only document data or image data.

  One or a plurality of display terminal devices having a display unit and an operation unit may be connected to the document display device 10 via a network, and the document may be displayed on the display terminal device. For example, a document display device 10 and a display terminal device are installed in a library or the like, and image data of a library book in the library is stored in the document display device 10. In this way, it is possible for the library user to roughly grasp the contents of the holding book using the display terminal device.

  Only a desired area may be extracted and displayed from the text area, figure area, and table area recognized by the layout analysis. For example, in technical papers in which numerical data is important, it is possible to quickly view numerical data by displaying only pages with figures and tables.

It is a figure which shows the structure of the document display apparatus which concerns on one Embodiment of this invention. It is a figure which shows the flow of the process performed when CPU runs a program. It is a figure which shows the detailed flow of a structure data creation process. It is a figure which shows the example of the document made into the object of the process by a document display apparatus. It is a figure which shows the example of structure data. It is a figure which shows the method of weighting. It is a figure which shows transition of change amount. It is a figure which shows the detailed flow of a document display process. It is a figure which shows the example of a setting of the threshold value of change amount. It is a figure which shows an example of a user interface. It is a figure which shows the virtual module formed when CPU runs a program.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Document display apparatus 101 ... CPU, 102 ... ROM, 103 ... RAM, 105 ... Display part, 107 ... Operation part, 109 ... Scanner, 111 ... Printer, 113 ... Network, 117 ... Document storage part, 118 ... Document processing Part,
21 ... Document acquisition means, 22 ... First acquisition means, 23 ... Second acquisition means, 24 ... Structure data generation means, 25 ... Change amount calculation means, 26 ... Change amount storage means, 27 ... Display means.

Claims (5)

For each page of a document made up of a plurality of pages, layout information representing the layout of the constituent elements constituting the page is acquired, and structural data representing the hierarchical structure on the layout between the regions occupied by the constituent elements on the page is obtained. Structure data generation means to generate;
A change amount calculating means for calculating a change amount indicating a degree of change in the hierarchical structure between the attention page and the page immediately before the attention page in the ascending or descending order of the pages;
A document display device comprising: a display unit that compares a change amount obtained by the change amount calculation unit with a predetermined threshold value and displays the attention page when the change amount is equal to or greater than the threshold value. Document acquisition means for acquiring document data including document layout information or image data representing an image of the document;
First acquisition means for extracting layout information from the document data, and second acquisition means for acquiring layout information of the document by analyzing an image of the document represented by the image data,
The structure data generation unit acquires layout information using the first acquisition unit when the document data is acquired by the document acquisition unit, while the image data is acquired by the document acquisition unit. The document display apparatus according to claim 1, wherein the layout information is acquired using the second acquisition unit. Change amount storage means for storing the change amount obtained by the change amount calculation means in association with the page of interest;
The said display means extracts the page whose variation | change_quantity memorize | stored by the said variation | change_quantity storage means is more than a threshold value, and displays the image of the extracted page in the ascending order or descending order of a page. Or the document display apparatus of 2. Computer equipment,
For each page of a document made up of a plurality of pages, layout information representing the layout of the constituent elements constituting the page is acquired, and structural data representing the hierarchical structure on the layout between the regions occupied by the constituent elements on the page is obtained. Structure data generation means to generate;
A change amount calculating means for calculating a change amount indicating a degree of change in the hierarchical structure between the attention page and the page immediately before the attention page in the ascending or descending order of the pages;
A program for comparing the amount of change obtained by the amount-of-change calculating means with a predetermined threshold and functioning as display means for displaying the page of interest when the amount of change is equal to or greater than the threshold. For each page of a document made up of a plurality of pages, layout information representing the layout of the constituent elements constituting the page is acquired, and structural data representing the hierarchical structure on the layout between the regions occupied by the constituent elements on the page is obtained. A structural data generation step to generate;
A change amount calculating step for calculating a change amount indicating a degree of change in the hierarchical structure between the attention page and the page immediately before the attention page in the ascending or descending order of the pages;
A document display method comprising: a display step of comparing a change amount obtained by the change amount calculation unit with a predetermined threshold value and displaying the page of interest when the change amount is equal to or greater than the threshold value.

Images