JP3617230B2 - Document processing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a document processing apparatus that adds information to a document image including elements such as characters, figures, lines, and the like, and a document processing apparatus that extracts and outputs information from the document image to which information is added.
[0002]
[Prior art]
In recent years, the exchange of digital information via networks such as LAN (Local Area Network), WAN (Wide Area Network), Internet, etc. has become popular, and it is frequently performed to distribute documents as electronic documents. .
On the other hand, paper used conventionally and other output media (hereinafter collectively referred to as paper) have lost their importance as media in terms of portability, ease of writing, cost, and the like. Even when the user obtains a document in the form of an electronic document, the electronic document is often output and used as a paper document.
[0003]
Here, there is a strong desire to restore the output paper document to the original electronic document, but when the electronic document is output as a paper document, the logical structure and code information of the document held by the electronic document For example, information such as character recognition and figure recognition is required for restoration. However, with current technology, situations such as inability to recognize or incorrect recognition occur, and it is far from complete restoration.
[0004]
In addition, electronic documents themselves have evolved, and some electronic documents such as Hypertext, structured documents, etc. that have information other than visible forms have appeared. When output, a situation occurs in which important information is lost.
For example, Hypertext is composed of nodes and links, and the contents of a document can be described in units of nodes, and the relationship between nodes can be described by links. However, link information is usually visible to the human eye. Is not displayed, and when output as a paper document, the link information is not output and the link information is lost.
[0005]
Also, electronic documents may be given data encryption or digital signatures to prevent data tampering to prevent leakage of confidential information, but these information are digital information that is meaningless to humans. Therefore, it is not normally displayed, and when it is output as a paper document, the information is lost without being output.
[0006]
In view of the above situation, in the invention described in Japanese Patent Laid-Open No. 1-197878 (hereinafter referred to as Document 1) and the invention described in Japanese Patent Laid-Open No. 6-342426 (hereinafter referred to as Document 2). For the purpose of accurately restoring the contents of the original electronic document, or expressing digital information that was not normally expressed in paper documents, a barcode, a two-dimensional barcode with a large amount of information, etc. By outputting to a paper document, digital data is expressed on the paper document.
[0007]
However, in the inventions described in these documents 1 and 2, a barcode display area is required, and a pattern that is meaningless to humans must be output to the paper document, which impairs the design of the paper document. And the location of confidential information is clearly indicated, causing problems such as deciphering and falsification.
[0008]
In order to deal with these problems, Japanese Patent Laid-Open No. 1-306958 (hereinafter referred to as Document 3) coexists a conventional information expression that is readable by humans and an information expression that is difficult for humans to view and is readable by machines. Thus, an invention for embedding digital information without affecting the appearance of the document is disclosed.
[0009]
[Problems to be solved by the invention]
However, the invention described in the above-mentioned document 3 utilizes a substance or magnetism that is difficult for humans to visually check, and it has been difficult to realize it using a conventional device such as a printer. The invention described in Document 3 describes an invention that can be realized by a device such as a printer. However, the invention draws a character with a code having a relatively uniform density. There are problems that shading is limited and character quality deteriorates.
[0010]
The present invention has been made in view of the above-described conventional circumstances, and provides a document processing apparatus capable of outputting a paper document in which additional information used by a machine is embedded without affecting a document image read by a human. The purpose is to do.
Another object of the present invention is to provide a document processing apparatus that can extract and output additional information from a paper document in which the additional information is embedded.
[0011]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention is made by paying attention to a pixel constituting a document image read by a human in a paper document, and expresses additional information used by the machine by a drawing position of the pixel. .
Note that the above-described pixel is a minimum unit that can be drawn by an output device such as a printer, a copier, a facsimile machine, a printing plate generation device, or the like.
[0012]
A document processing apparatus according to the present invention is a document processing apparatus for drawing a document image on a line screen, a document image input means for inputting a document image, and an information input means for inputting additional information to be added to the document image. The image drawing means for drawing the document image using a line screen that changes the width of the screen line according to the density of the document image to be output, and the line width of the line screen when drawing the document image by the image drawing means The drawing position of the screen line is set in the line width direction of the line screen according to the additional information for the band-shaped portion in the direction, and the additional information is set for the other band-shaped portions having a predetermined relationship with the band-shaped portion. A position setting means for setting the drawing position of the screen line at the position corresponding to the start point and the end point in the line width direction of the line screen, and the position setting means. According to the setting, characterized by comprising a control means for rendering the document image by the image drawing means by using the line screen.
[0013]
Here, the screen line may be a single pixel or a plurality of pixels.
Further, the band-shaped portion refers to a portion in which screen lines are collected in the line width direction of the line screen.
The screen line of the band-shaped portion that represents the range for setting the additional information and the screen line of the band-shaped portion for setting the additional information may have different numbers of pixels.
In addition, the other band-shaped part having a predetermined relationship with the band-shaped part refers to another band-shaped part that can identify the band-shaped part, for example, other band-shaped part adjacent to the band-shaped part. That means.
[0014]
In the above document processing apparatus, basically, a document image input from the document image input means is drawn using a line screen that changes the width of the screen line according to the density of the document image to be output by the image drawing means. To do. When the additional information input from the information input unit is embedded in the document image, when the document image is drawn by the image drawing unit, the position setting unit sets the additional information for the band-shaped portion in the line width direction of the line screen. Accordingly, the drawing position of the screen line is set in the line width direction of the line screen, and the position corresponding to the start point and end point of the range in which the additional information is set for the other band-like part having a predetermined relationship with the band-like part The screen line drawing position is set in the line width direction of the line screen, and the control means draws the document image by the image drawing means using the line screen according to the setting by the position setting means.
[0015]
A document processing apparatus according to the present invention is a document processing apparatus that extracts and outputs additional information added to a document image from a document image drawn on a line screen, and the document image includes a line Regarding the band-shaped part in the line width direction of the screen, the drawing position of the screen line is changed in the line width direction of the line screen according to the additional information, and the band-shaped part having a predetermined relationship with the band-shaped part is drawn. The drawing position of the screen line at the position corresponding to the start point and end point of the range in which the additional information is set is changed in the line width direction of the line screen, and is drawn by scanning the document image. Scanning means for detecting displacement in the width direction, range specifying means for specifying a start point and an end point indicating a range in which additional information is set from the band-like portion where the displacement is detected, Additional information detecting means for detecting the displacement state of the screen line from the setting range of the additional information of the belt-like portion having a predetermined relationship with the belt-like portion, and outputting information added to the document image based on the detected displacement state And an additional information output unit.
[0016]
In the document processing apparatus according to the present invention described above, the drawing position of the screen line is changed in the line width direction of the line screen according to the additional information for the band-like portion in the line width direction of the line screen, and is drawn. The drawing position of the screen line at the position corresponding to the start point and the end point of the range in which the additional information is set is drawn in the line width direction of the line screen for the band part having a predetermined relationship with the band part. The scanning means scans the scanned document image and detects the displacement in the line width direction of the screen line, and the range specifying means specifies the start point and end point indicating the set range of the additional information from the band-like portion including the detected displacement. The additional information detecting means detects the displacement state of the screen line from the setting range of the additional information of the band-shaped part having a predetermined relationship with the band-shaped part, and the additional information output means detects the displacement. And outputs the added information in the document image based on the state.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
As a first embodiment of a document processing apparatus according to the present invention, a document processing apparatus that adds information to a document image and outputs the document image will be described with reference to FIG.
The document processing apparatus includes a document input unit 1 for inputting a document image and additional information to be added to the document image, an output image generating unit 2 for adding additional information to the document image, and a document image to which the additional information is added. And image output means 3 for outputting as a paper document.
[0018]
The document input unit 1 includes a document image input unit that inputs a document image and an information input unit that inputs additional information to be added to the document image.
The document image input means inputs a document image created by a document creation device such as a word processor. Note that component information such as characters and graphics in the document image is associated with attribute information indicating attributes such as the size and form of the component. For example, the component shown in FIG. This is realized by data having an element identification tag holding identification information to be expressed and attribute information regarding the component.
The information input means inputs information to be added to the component of the document image and associates the information with the component. For example, as shown in FIG. 2B, for the data in which the constituent element is associated with the attribute information, the constituent element is added to the additional information by constructing data obtained by adding the additional information to the constituent element. Associate.
[0019]
An example of a method for inputting additional information by the document input means 1 will be described with reference to FIG. FIG. 3 shows the display contents of the display device.
When the character image input means inputs the document image, the character image window A is output to the display device, the user selects the component Y in the character image window, and the attribute information of the selected component Y is displayed in the attribute window. Output as B. The attribute window B includes an “embedded information” area for designating information to be added to the component. Then, the user adds information to be added to the “embedded information” area, and the information input means accepts the specified additional information as an input.
Note that additional information can also be input to components such as figures and graphs as described above.
[0020]
The output image generation means 2 develops a document image into a raster image based on a preset output resolution of the output device, and stores density information (hereinafter referred to as pixel data) of each pixel (pixel) constituting the raster image. On the other hand, identification information representing a component including the pixel is added to create first raster image data. When pixels included in the same component are continuous in the main scanning direction, a data structure in which continuous pixel data is collected as shown in FIG.
[0021]
Further, the output image generating means 2 adds a modulation flag indicating whether or not to modulate the corresponding pixel to each pixel data in the first raster image data, and has a data structure shown in FIG. Second raster image data is created, and based on the identification information associated with the input additional information, the pixel group constituting the constituent element associated with the additional information is defined as the first raster image data. And detecting a pixel group having a predetermined density among the detected pixel group.
[0022]
Here, the modulation refers to a position at which the pixel P is drawn at a position different from the foremost portion in the main scanning direction within the line screen width shown in FIG. ) Means the position of the last part in the main scanning direction within the line screen width shown in FIG. Note that it is impossible for the human eye to recognize that the modulation has been performed.
The predetermined density means a density that can detect whether or not a pixel is modulated from a document image output as a paper document. If the density is too small or too large, it is not appropriate and the pixel is modulated. Thus, the output resolution depends on the output resolution of the apparatus that outputs the document image and the resolution of the apparatus that inputs the output document image. For example, when a document image is output by a 200 dpi printer and the document image is input by a scanner having an optical resolution of 600 dpi, a density of 20 to 80% is preferable.
[0023]
Further, the output image generation unit 2 sets a modulation flag corresponding to a pixel of the pixel group based on the input additional information, for example, as shown below. That is, in the first strip portion 4 in which screen lines (for example, a unit in which two pixels in the sub-scanning direction are combined) are collected in the main scanning direction so as to have the modulation pattern shown in FIG. One screen line is made to correspond to each digital data in the embedded data shown in FIG. 2E having the identification information of the component associated with the additional information and the sequence number. In the case of “1”, the screen line is set to the rear position within the screen width, that is, the drawing position of the screen line when modulation is performed. Is set at the screen line drawing position when modulation is not performed, and the modulation flag is set according to the setting.
[0024]
Note that if two screen lines adjacent in the main scanning direction are not to be embedded at the same time, the two adjacent screen lines are not simultaneously modulated. For this reason, whether or not the screen line to be embedded is modulated from the document image output as a paper document is determined based on the relationship between adjacent screen lines, for example, whether or not adjacent screen lines are in contact with each other. It can be easily recognized.
In addition, as described above, not only the additional information but also the identification number and sequence number of the component associated with the additional information are set as data to be embedded in the document image. For example, the additional information is set in one band-like portion. If it is not possible, additional information can be grasped without any trouble even if the setting is performed by being distributed over a plurality of strip portions. That is, the additional information associated with the same component can be associated with the same identification number, and the order in the additional information can be set by the sequence number. Can do.
[0025]
On the other hand, in the second strip portion 5 adjacent to the first strip portion 4 described above, screen lines at positions corresponding to the start position and end position of the range in which the embedded data is embedded (hereinafter referred to as a segment) are displayed. It is set at the rear position within the screen width, that is, the drawing position of the screen line when modulation is performed, and the modulation flag is set according to the setting.
Note that by using more pixels as screen lines, it is possible to more effectively correct the inclination of the paper document when the paper document is read by an image input device such as a scanner.
[0026]
The image output unit 3 receives the second raster image data in which the modulation flag is set by the output image generation unit 2, and outputs the document image as a paper document based on the second raster image data.
The image output means 3 is realized by an electrophotographic printer shown in FIG. 6, which includes an information divider 6, a D / A converter 7, a triangular wave oscillator 8, a selection circuit 9, and a comparator 10. A laser drive system 11 is provided.
[0027]
The information divider 6 divides the second raster image data into pixel data and a modulation flag, passes the pixel data to the D / A converter 7, and passes the modulation flag to the selection circuit 9.
The D / A converter 7 converts the pixel data received from the information divider 6 into analog voltage information, and outputs this to one input terminal of the comparator 10.
The triangular wave oscillator 8 generates a triangular wave for changing the drawing position of the output pixel in the width direction of the line screen (also referred to as the main scanning direction). Specifically, for example, a vertex as shown in FIG. Two types of triangular waves 12 and 13 having different positions are generated. Note that the width of one unit of the triangular waves 12 and 13 corresponds to one unit of the width of the line screen.
[0028]
The selection circuit 9 selects one of the triangular waves 12 and 13 generated by the triangular wave oscillator 8 based on the modulation flag received from the information divider 6, and outputs this to the other input terminal of the comparator 10. To do. For example, when the modulation flag is set not to perform modulation, the triangular wave 12 is selected. When the modulation flag is set to perform modulation, the triangular wave 13 is selected and output.
[0029]
The comparator 10 compares the analog voltage of the pixel data with the triangular wave level (analog voltage). When the triangular wave level is higher than the analog voltage of the pixel data, the comparator 10 is “H” (that is, the laser is turned on), L ″ (that is, the laser is turned off) is output. Accordingly, the “H” level is input to the laser drive system 11 at the latest timing when the triangular wave 12 is selected, and at the earliest timing when the triangular wave 13 is selected.
[0030]
The laser drive system 11 is a means for drawing output pixels using a line screen, and draws while scanning pixels to be output to paper in response to a laser ON command.
Therefore, when the triangular wave 12 is selected, the output pixel is drawn at the rearmost portion 14 in the main scanning direction within the line screen width, and when the triangular wave 13 is selected, the output pixel is main scanned within the line screen width. It is drawn on the frontmost part 15 of the direction. It should be noted that the output pixel width is wider as the density is higher.
[0031]
That is, according to the electrophotographic printer having the above configuration, the second pixel image data is divided into the pixel data and the modulation flag by the information divider 6, and the pixel data is converted into an analog voltage by the D / A converter 7. One of the triangular waves 12 and 13 generated by the triangular wave oscillator 8 is selected by the selection circuit 9 according to the modulation flag and input to the comparator 10. The comparator 10 controls the laser driving system 11 at a timing based on the shape of the selected triangular wave, and draws an output pixel at a position displaced in the width direction within the width of the line screen.
[0032]
Next, the operation of the document processing apparatus according to the first embodiment will be described with reference to the drawings.
First, when a document image is input by the document input unit 1 and additional information to be added to the document image is input, an operation of outputting the document image to which the additional information is added as a paper document is shown in FIG. Will be described roughly.
When the output image generating means 2 generates a raster image from the input document image, an element identification tag for identifying a component including the pixel is attached to the pixel data of the pixel constituting the raster image. First raster image data is generated (step S1), and further, second raster image data in which a modulation flag is added to the pixel data in the generated first raster image data is generated, and the input additional information Accordingly, the output image generation process shown below for setting the modulation flag is performed (step S2), and the image output means 3 outputs the document image as a paper document based on the second raster image data (step S3).
[0033]
The output image generation processing by the output image generation means 2 will be described in detail with reference to FIG.
First, the length (modulation length) of the screen line set in advance in the sub-scanning direction and the density condition of the pixel that can detect the modulation when modulated are grasped (step S4), and the first raster image data Second raster image data is created based on the pixel data in the middle (step S5).
[0034]
Then, it is detected whether or not the following modulation flag setting processing has been performed on the additional information input by the document input means 1 (step S6), and the following processing is performed on the additional information that has not been performed.
That is, a pixel group having the same identification information as the identification information of the component associated with the additional information and having no modulation flag set is detected from the first raster image data in the main scanning direction. (Step S7). If the information cannot be detected, the additional information cannot be embedded, and an error is notified to the user (steps S8 and S9).
[0035]
Next, it is detected whether additional information can be embedded in the detected pixel group (steps S8 and S10). Here, whether or not the density of the detected pixel group satisfies the grasped density condition can be ensured twice as long as the modulation length by the modulation pattern of the format shown in FIG. It is determined whether or not the width in which a part of the additional information can be embedded can be reported.
When it is detected that embedding is performed, the modulation flag of the corresponding pixel of the second raster image data is set to realize a modulation pattern according to the additional information (step S11). The modulation flag corresponding to the pixel group is set to non-modulation (step S12), and other embeddable pixel groups are detected (steps S7 to S10).
[0036]
If all the additional information could not be embedded, 1 was added to the sequence number in the embedded data when embedding the rest of the additional information (steps S13 and S14). The above processing (steps S7 to S14) is repeated.
As a result, when all the additional information is embedded, the other additional information is processed in the same manner (steps S6 to S14). When all the additional information is embedded, the modulation flag is not set. The modulation flag in the second raster image data is set to no modulation, and the second raster image data is transferred to the image output means 3 (step S15).
[0037]
The image output means 3 that has received the second raster image data outputs a document image having a modulation pattern as shown in FIG. 5 as a paper document.
Therefore, it is possible to output a paper document in which additional information is embedded without affecting a document image read by a human.
[0038]
Next, as a second embodiment of the document processing apparatus according to the present invention, an example of a document processing apparatus that extracts and outputs information from the paper document output by the document processing apparatus according to the first embodiment described above is shown in FIG. Will be described with reference to FIG.
This document processing apparatus outputs an image input unit 21 for inputting a document image to which additional information is added from a paper document, an additional information recognition unit 22 for extracting additional information from the input document image, and outputs the extracted additional information. Document output means 23.
[0039]
The image input unit 21 is realized by a conventionally known device such as an image scanner, and by scanning a document image output as a paper document, the position of pixels in the document image is grasped, and the document image is obtained. Capture as raster image data.
[0040]
The additional information recognition unit 22 grasps the screen width and the modulation length of the screen line from the pixel position grasped by the image input unit 21.
The screen width can be obtained from the interval between the drawing start position of one pixel and the drawing start position of the next pixel. It should be noted that each pixel is subject to no modulation, and in this embodiment, the screen width can be grasped without modulation for the first scanned portion of the document image. it can.
Further, the modulation length of the screen line is grasped by detecting the modulated pixel based on the screen width and the pixel position, and detecting the modulated pixel continuous in the same sub-scanning direction of the pixel. can do.
Further, the additional information recognition unit 22 detects the modulated screen line and specifies the start position and end position of the segment. For example, in the document image output by the document creation apparatus of the first embodiment, when scanning, the screen line where the modulation is detected first or after the end of the segment indicates the start position of the segment. The screen line representing the end position of the segment is the screen line representing the start position, and the screen line where the modulation is detected next to the screen line representing the start position.
[0041]
Further, the additional information recognizing unit 22 determines the raster image of the segment portion based on the angle formed by the straight line connecting the screen lines indicating the start position and the end position of the detected segment and the direction scanned by the image input unit 21. Correction in the scanning direction during data reading (so-called skew correction) is performed.
Further, the additional information recognition unit 22 grasps the segment based on the modulation length of the screen line, the screen width, and the screen line indicating the start position of the segment, and further, the target screen in which the information in the segment is embedded. By detecting whether or not the line is modulated, data embedded in the segment (data in the format shown in FIG. 2D) is detected.
[0042]
The document output unit 23 summarizes the data obtained for each segment detected by the additional information recognition unit 22 for each identical identification information, and further rearranges the data according to the sequence number to restore the original additional information. The output is made to correspond to the area where the segment is embedded.
[0043]
Next, the operation of the document processing apparatus according to the second embodiment will be described with reference to FIG.
First, the image input means 21 scans a paper document containing additional information to capture raster image data (step S21), and the additional information recognition means 22 modulates pixels based on the captured raster image data. By detecting whether or not there is a screen line indicating the start position and end position of the segment, the segment is detected (steps S22 and S23). If the segment cannot be detected, the image input means 21 sequentially takes in the raster image data (step S21).
[0044]
When a segment is detected, an angle formed by a straight line connecting screen lines representing the start position and end position of the segment and the scanning direction by the image input means 21 is calculated, and the image input means is based on the calculation result. The skew correction in the scanning direction by 21 is performed, and the influence on the raster image data due to the inclination of the paper document itself is corrected (step S24).
[0045]
Next, the image input means 21 takes in the raster image data of the detected segment portion in the scan direction in which the skew is corrected (step S25), and the additional information recognition means 22 performs the following embedded information extraction processing from the taken-in raster image data. (Step S26), the information indicating the segment area in the document image and the data embedded in the segment are stored in a storage device (not shown) (step S27).
[0046]
When the above-described processing (steps S21 to S27) is performed on the raster image data subsequent to the above-described segment and the above-described processing is completed for all the raster image data, the following embedded information output processing is performed. (Steps S22 and S28).
[0047]
Next, the embedded information extraction process will be described with reference to FIG.
First, the additional information recognition unit 22 detects the screen width of the document image and the modulation length of the screen line based on the pixel position grasped by the image input unit 21 (step S29). A position (hereinafter referred to as a modulation position) that exists when the screen line to be embedded in the segment is not modulated by the position of the screen line representing the start of the segment, the screen line modulation length, and the screen width. .) Is specified (step S30).
Next, it is detected whether or not a screen line exists at the modulation position (step S31).
[0048]
If there is a screen line, it means that the screen line is not modulated. Therefore, “0” is embedded, and the bit “0” is grasped as a part of the embedded data (step S32). On the other hand, if it does not exist, it means that it is modulated, so that “1” is embedded, and bit “1” is grasped as a part of the embedded data (step S33).
The above-described processing (steps S30 to S34) is performed on all the modulation positions in the segment, and the embedded data embedded in the segment can be grasped.
[0049]
Next, the embedded information output process will be described with reference to FIG.
First, the document output means 23 reads the embedded data embedded in the segment from the storage device and the area information of the segment (step S35), and for each embedded data associated with the same component, that is, Each embedded data including the same identification information is grouped and classified into a set (step S36), and the original additional information is restored by rearranging the embedded data in the set in order of the sequence number in each data (step S36). Step S37). Then, based on the region information of the segment in which each embedded data grouped in the same set is embedded, a minimum rectangular region surrounding the segment is calculated (step S38), and the restored additional information is output. At the same time, a portion in the document image corresponding to the rectangular area is output (step S39).
[0050]
The additional information and the area where the additional information has been added are displayed on the display device as shown in FIG. 13, for example.
That is, the document image C is displayed on the display, the area D in the document image C is displayed as a shadow, and the additional information E that is embedded is displayed.
[0051]
Therefore, it is possible to grasp and output the additional information and the area in the document image in which the additional information is embedded from the paper document to which the additional information is added.
[0052]
Next, an example of outputting a Hypertext document as a paper document by the document processing apparatus according to the first embodiment will be described with reference to FIG.
As shown in FIGS. 14 (a) and 14 (b), the Hypertext document is displayed with a character or the like attached with an anchor such as a shadow or underline. The character or the like as shown in FIG. 14 (c) is displayed on the anchor. Link information to a document having information related to is associated.
When outputting such a Hypertext document as a paper document, the document input means 1 accepts the link information as additional information, and associates the accepted link information with the anchor, thereby linking to the output document image. Information can be added. The link information can be extracted from the paper document output by the document processing apparatus according to the second embodiment.
[0053]
Next, an example of outputting a structured document as a paper document by the document processing apparatus according to the first embodiment will be described with reference to FIG.
The structured document is displayed on the display as shown in FIG. 15A. For example, for the specific part “prior art”, the logical structure in the document is shown in FIG. 15B. In this structure, logical information such as “chapter” is associated.
When outputting such a structured document as a paper document, the document input unit 1 accepts the logical information as additional information, and adds an underline to a specific part associated with the logical information. By associating the logical information with the underline, the logical information can be added to the output document image. FIG. 15C shows an example of output as a paper document, in which logical information is embedded in the underlined portion. The logical information can be extracted from the paper document output by the document processing apparatus according to the second embodiment.
[0054]
A case where a part of document information is added to a paper document and output by the document processing apparatus according to the first embodiment will be described with reference to FIG.
In this example, the graph displayed on the display as shown in FIG. 16A has the numerical information shown in FIG.
In this case, the document input means 1 accepts numerical information held in the graph as additional information, and associates the numerical information with the rectangle of the bar graph, thereby adding numerical information to the output document image. it can. The numerical information can be extracted from the paper document output by the document processing apparatus according to the second embodiment.
[0055]
An example of embedding an electronic signature or confidential information in a paper document by the document processing apparatus according to the first embodiment will be described with reference to FIG.
In this case, the document input means 1 accepts an electronic signature or confidential information as additional information and, for example, associates it with a logo portion F in the input document, thereby providing an electronic signature or confidential information on the output document image. Can be added. An electronic signature or secret information can be extracted from a paper document output by the document processing apparatus according to the second embodiment.
[0056]
In the above-described embodiment, the modulation pattern shown in FIG. 5 is used. However, the present invention is not limited to this modulation pattern, and screen lines corresponding to the band-shaped portion in the line width direction of the line screen according to additional information are used. Is set in the line width direction of the line screen, and the screen line at a position corresponding to the start point and end point of the range in which the additional information is set for the other band-like part having a predetermined relationship with the band-like part. Any modulation pattern that sets the drawing position in the line width direction of the line screen may be used.
For example, the band-shaped portion indicating the setting range of the additional information and the band-shaped portion for setting the additional information may be separated from each other by 5 pixels in the sub-scanning direction.
[0057]
In the first and second embodiments described above, the embedding of additional information and the extraction of additional information into a paper document composed of monochrome pixels has been described. However, Y (yellow), M (magenta), C The present invention can also be applied to a paper document composed of a plurality of pixels such as (cyan) and K (black).
[0058]
In the above-described embodiment, each functional unit is configured by a processor executing a control program (stored in advance in ROM, RAM, etc.). In the present invention, these functional units are independent hardware circuits. You may comprise as.
The control program can be stored in a storage medium such as a floppy disk or a CD-ROM, input to the computer from the storage medium, and executed by the processor to execute the processing according to the present invention. .
[0059]
【The invention's effect】
As described above, in the document processing apparatus according to the present invention, when drawing a document image, the drawing position of the screen line is set according to the additional information for the band-like portion in the line width direction of the line screen. In addition to setting the width direction, the drawing position of the screen line at the position corresponding to the start point and end point of the range where the additional information is set for the band portion having a predetermined relationship with the band portion is set in the line width direction of the line screen. Because it is set and the document image is drawn according to the setting, additional information used by the machine is embedded in the paper document without affecting the document image read by humans without using special ink or special paper. Can do.
[0060]
Further, in the document processing apparatus according to the present invention, a paper document is scanned to detect a displacement in the line width direction of the screen line, and a start point and an end point indicating a set range of additional information from a belt-like portion including the detected displacement Is detected, and the additional information is extracted by specifying the setting range of the additional information of the belt-shaped portion having a predetermined relationship with the belt-shaped portion, and therefore the additional information can be extracted from the paper document.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a document processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a data structure according to the present invention.
FIG. 3 is a diagram for explaining an additional information input method according to the first embodiment of the present invention;
FIG. 4 is a diagram for explaining pixel modulation according to the first embodiment of the present invention;
FIG. 5 is a diagram for explaining a modulation pattern according to the present invention.
FIG. 6 is a configuration diagram of an electrophotographic printer as image output means according to the first embodiment of the present invention.
FIG. 7 is a flowchart illustrating an operation for outputting a document image to which additional information is added on paper according to the first embodiment of the present invention.
FIG. 8 is a flowchart illustrating output image generation processing according to the first embodiment of the present invention.
FIG. 9 is a block diagram of a document processing apparatus according to a second embodiment of the present invention.
FIG. 10 is a flowchart illustrating the operation of the document processing apparatus according to the second embodiment of the present invention.
FIG. 11 is a flowchart illustrating an embedded information extraction process according to the second embodiment of the present invention.
FIG. 12 is a flowchart illustrating an embedded information output process according to the second embodiment of the present invention.
FIG. 13 is a diagram for explaining a display example of additional information according to the second embodiment of the present invention.
FIG. 14 is a diagram illustrating an example of outputting a Hypertext document as a paper document in the present invention.
FIG. 15 is a diagram illustrating an example of outputting a structured document as a paper document in the present invention.
FIG. 16 is a diagram for explaining an example when a part of document information is embedded in a paper document in the present invention.
FIG. 17 is a diagram illustrating an example of embedding an electronic signature or secret information in a paper document in the present invention.
[Explanation of symbols]
1. Document input means,
2. Output image generation means,
3. Image output means,
4. First strip part
5. Second belt-like part

Claims (4)

In a document processing apparatus that draws a document image on a line screen,
A document image input means for inputting a document image;
Information input means for inputting additional information to be added to the document image;
Image drawing means for drawing a document image using a line screen that changes the width of the screen line according to the density of the document image to be output;
When drawing a document image by the image drawing means, the drawing position of the screen line is set in the line width direction of the line screen according to the additional information for the band part in the line width direction of the line screen, and Position setting means for setting the drawing position of the screen line at the position corresponding to the start point and the end point of the range in which the additional information is set for the other band-shaped part having a predetermined relationship in the line width direction of the line screen,
A document processing apparatus comprising: control means for drawing a document image by the image drawing means using a line screen in accordance with the setting by the position setting means. The document processing apparatus according to claim 1,
Furthermore, it comprises an area detecting means for detecting an area having a predetermined density from the document image to be output,
The document processing apparatus, wherein the position setting unit sets a drawing position of a screen line for a band-shaped portion constituting the area. In the document processing apparatus according to claim 1 or 2,
The information input means inputs additional information in association with elements constituting the document in the document image,
The document processing apparatus, wherein the position setting means sets a drawing position of a screen line for a band-shaped portion constituting an element associated with the additional information. A document processing apparatus that extracts and outputs additional information added to a document image drawn from a document image drawn on a line screen,
The document image is drawn by changing the drawing position of the screen line in the line width direction of the line screen according to the additional information for the band part in the line width direction of the line screen, The drawing position of the screen line at the position corresponding to the start point and the end point of the range where the additional information is set for the other band-shaped part having the relationship of is drawn in the line width direction of the line screen, and is drawn.
Scanning means for scanning the document image and detecting displacement in the line width direction of the screen lines;
A range specifying means for specifying a start point and an end point indicating a range in which additional information is set from the belt-like portion in which the displacement is detected;
Additional information detecting means for detecting a displacement state of the screen line from a setting range of additional information of the belt-shaped portion having a predetermined relationship with the belt-shaped portion;
An additional information output unit that outputs information added to a document image based on the detected displacement state.

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