KR20080110532A - Information processing apparatus and method thereof - Google Patents

Abstract

An information processing apparatus and a method thereof are provided to detect mismatch of inserted information due to extraction error of an external contact square. A document input unit(401) inputs a document comprised of characters. An inserting information input unit(404) inputs inserted information in a document. A synchronization information input unit(405) inputs synchronization information made of a preset bit pattern. A synthesizing unit(406) generates a synthesizing inserting information. An inserting unit(407) prints a document after the insertion.

Description

Information processing apparatus and its method {INFORMATION PROCESSING APPARATUS AND METHOD THEREOF}

The present invention relates to a technique for embedding information in a document and a technique for extracting embedded information.

When embedding watermarking information in characters, it is necessary to extract the circumscribed rectangle in units of one character before embedding. However, for example, an extraction error occurs in which a character composed of sides and rooms is extracted as two characters separately. In this case, if the watermark information is embedded with an extraction error, the watermark information is shifted when extracting the embedded watermark information again. For example, suppose that Fig. 1A originally shows a character to be extracted as a circumscribed rectangle, and embeds watermark information as shown in Fig. 1B in the character. However, as shown in Fig. 1C, when the circumscribed rectangle is extracted, information is extracted from each character extracted from the circumscribed rectangle. Therefore, as a result, the watermark information as shown in Fig. 1D is extracted. Japanese Patent Laid-Open No. 2004-247883 (Patent 1) discloses a technique for embedding watermark information and synchronization information in each character in order.

However, in the technique disclosed in Document 1, it is not possible to specify the position of the error of extracting the circumscribed rectangle, so that the watermarking information needs to be embedded several times in the circumscribed rectangle. Further, since the watermark information on the rear side is shifted from the circumscribed rectangle where the extraction error occurs, it cannot be referred to.

Therefore, an object of the present invention is to detect the deviation of embedding information caused by the extraction error of the circumscribed rectangle.

In the present invention, an information processing apparatus for embedding n-bit information (n is an integer of 2 or more) in each character in a document, comprising: document input means for inputting a document composed of characters, and embedding information to be embedded in the document; By embedding the embedding information input means to input, the synchronization information input means which inputs the synchronization information which consists of a plurality of bits, and consists of a preset bit pattern, the bits which comprise the input embedding information, and the bits which comprise the said synchronization information, Combining means for generating synthesis embedding information, embedding means for embedding the synthesis embedding information generated by the synthesizing means into each character in the document input by the document input means, and outputting the document after embedding; The embedding means is provided with an information processing apparatus characterized by embedding at least one bit of synchronization information in each character.

Further, in the present invention, information for extracting information from a document image in which n bits (n is an integer of 2 or more) is embedded in each character in the document image, and at least one bit of the n bits is embedded as synchronization information. A processing apparatus comprising: document image input means for inputting a document image, synthesized embedding information extracting means for obtaining a circumscribed rectangle of each character in the input document image, and extracting information embedded in the characters in the circumscribed rectangle; Separation means for separating the synchronization information and embedding information from the synthetic embedding information extracted by the information extraction means, synchronization information input means for inputting synchronization information, synchronization information separated by the separation means, and the synchronization information input By comparing the synchronization information inputted by the means, the extraction error of the synthesis embedding information extraction means is determined, and there is an extraction error. If it is determined, the synchronization information and the synchronization information input by the input means separated by the separating means to match, the information processing apparatus comprising a correction means for correcting the composite embedded information is provided.

Moreover, in this invention, as an information processing method which embeds the information of n bits (n is an integer of 2 or more) in each character in a document, the document input process of inputting the document which consists of characters, and the embedding to be embedded in the said document. A buried information input step of inputting information, a synchronous information input step of inputting synchronous information composed of a plurality of bits and having a preset bit pattern, bits constituting the input buried information, and bits constituting the synchronous information By a synthesis process, a synthesis step of generating synthesis embedding information, and a embedding process of embedding the synthesis embedding information generated in the synthesis process into each character in the document input in the document input process, and outputting the document after embedding; In the embedding process, at least one bit of synchronization information is embedded in each character.

Further, in the present invention, information for extracting information from a document image in which n bits (n is an integer of 2 or more) is embedded in each character in the document image, and at least one bit of the n bits is embedded as synchronization information. A processing method includes: a document image input step of inputting a document image, a synthetic embedding information extraction step of obtaining an external quadrangle of each character in the input document image, and extracting information embedded in the characters in the external quadrangle; A separation step of separating the synchronization information and the embedding information from the synthetic embedding information extracted in the information extraction step, a synchronization information input step of inputting synchronization information, synchronization information separated in the separation step, and the synchronization information input step By comparing the input synchronization information, the extraction error of the synthesis embedding information extraction step is determined, and it is determined that there is an extraction error. Wu, and the synchronization information is separated in the separation step, the synchronization information input in the input step to match, the information processing method characterized by comprising a correction step of correcting the composite embedded information is provided.

According to the present invention, the deviation of embedding information due to the extraction error of the circumscribed rectangle can be detected.

The features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

First, the whole structure of an information processing apparatus is demonstrated in detail with reference to drawings.

[Overall configuration]

4 is a schematic configuration diagram of an information processing device (embedded processing) according to an embodiment of the present invention. The information processing apparatus obtains a circumscribed rectangle of each character in a document and embeds information for each character in the area indicated by the circumscribed rectangle. In this case, it is assumed that n bits (n is an integer of 2 or more) are embedded in one character.

First, the document 400 composed of characters is optically read and input to the document input unit 401 as document image data, and then the document analysis unit 402 extracts a circumscribed rectangle (character area) in the document 400. This is done. Next, the embedding information 403 to be embedded in the document 400 is input to the embedding information input unit 404. Thereafter, synchronization information composed of a plurality of bits and consisting of a preset bit pattern is input to the synchronization information input unit 405. Thereafter, the synthesis unit 406 generates synthesized embedded information by alternately arranging n-1 bits constituting the input embedded information 403 and one bit of synchronization information.

Next, the embedding unit 407 embeds the synthetic embedding information generated by the combining unit 406 into the characters in the document 400 input by the document input unit 401, and outputs the document 409 after embedding. It outputs from the part 408.

The embedding unit 407 also includes a storage unit for storing 2 ⁿ embedding patterns for embedding n bits in one character. Further, the embedding unit 407 selects any one of the embedding patterns stored in the storage unit in accordance with the value of n bits in the synthetic embedding information generated by the synthesis unit 406, and selects one of the embedded rectangles in the external rectangle. The mask part which masks a character image is provided.

In this embodiment, an error correction information adding unit (not shown) for adding error correction information to the embedding information 403 input from the embedding information input unit 404 is provided. The synthesizing unit 406 synthesizes the addition result of the error correction information output from the error correction information adding unit of the embedding information input unit 404 and the synchronization information input from the synchronization information input unit 405.

5 is a schematic configuration diagram of an information processing device (extraction process) according to an embodiment of the present invention. The information processing apparatus receives a document image, obtains a circumscribed rectangle of each character in the document image, and extracts information embedded in the characters in the circumscribed rectangle.

First, the document image 500 is input from the document image input unit 501. Next, in the document analysis unit 502, a circumference rectangle of each character in the document image 500 input by the document image input unit 501 is obtained, and the information embedded in the characters in the area of the circumference rectangle is synthesized embedding information. It extracts from the extraction part 503. Next, the synthesis embedding information extracted by the synthesis embedding information extracting unit 503 is separated into synchronization information and embedding information by the separating unit 504. Here, n-1 bits constituting the embedding information and one bit of the synchronization information are alternately separated from the synthetic embedding information. Alternatively, the synchronization information may be first extracted from the embedding embedding information, and the information excluding the synchronization information may be embedded information embedded in the document image 500.

The synchronization information input unit 506 inputs synchronization information composed of a plurality of bits stored in the storage unit 505 and composed of a preset bit pattern. The error correction unit 507 determines the extraction error of the synthesis embedding information extraction unit 503 by comparing the synchronization information extracted from the synthesis embedding information extraction unit 503 with the synchronization information input from the synchronization information input unit 506. do. When it is determined that there is an extraction error, the synthesis embedding information is corrected so that the synchronization information extracted by the synthesis embedding information extraction unit 503 and the synchronization information input by the synchronization information input unit 506 coincide. Examples of the correction processing of the composite embedded information include bit insertion, bit deletion, bit inversion, and the like. The embedding information output unit 508 outputs embedding information after being processed by the error correction unit 507.

6 is an electrical configuration diagram of the information processing device according to one embodiment of the present invention. In addition, in realizing the information processing apparatus of this invention, it is not essential to utilize all the functions shown in FIG.

The computer 601 is a general-purpose information processing apparatus, such as a personal computer and a built-in system, which are generally prevalent. The computer 601 can receive an image read from an image input device such as a scanner 617, and can edit and store it. It is also possible to print an image obtained by the image input device from the printer 616. In addition, the instruction from the user is performed by input operations from the mouse 613, the keyboard 614, the touch panel 619, and the like. Inside the computer 601, since each block is connected by the bus 607, various data exchanges are possible.

The CPU 602 can control the operation of each block inside the computer 601 or execute a program stored therein. The main memory device (consisting of RAM) 603 is a device that temporarily stores a program or image data of a processing target for processing performed by the CPU 602. The hard disk (HDD) 604 is a device capable of storing in advance programs and image data transmitted to the main memory device 603 or the like, or storing image data after processing.

The scanner interface 615 is an interface that is connected to a scanner 617 that reads an original, a film, or the like and generates image data, and can receive image data obtained by the scanner 617. The printer interface 608 is connected to a printer 616 that prints image data, and is an interface that can transmit the image data to be printed to the printer 616.

The CD drive 609 is a device capable of reading or writing data stored in a CD (CD-R / CD-RW), which is one of external storage media. The FDD drive 611 is a device capable of reading from or writing to the FDD similarly to the CD drive 609. The DVD drive 610, like the FDD drive 611, is a device capable of reading from and writing to a DVD. When programs are stored in CD, FDD, DVD, and the like, these programs are installed in the HDD 604, and transferred to the main memory 603 as necessary.

The input interface 612 is an interface connected for receiving input instructions from the mouse 613 or the keyboard 614. The touch panel interface 618 is an interface connected to receive an input instruction from the touch panel 619. The monitor 606 is a display device that can display the extraction processing result and the processing of the embedded information. The video controller 605 is a device for transmitting display data to the monitor 606.

In addition, the present invention may be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, or the like) or may be applied to an MFP composed of one device.

In the above configuration, the program loaded in the main memory device 603 is executed by the CPU 602 or the like to function as an information processing device.

Next, each process performed by the information processing apparatus which has the structure mentioned above is demonstrated concretely in each embodiment.

<First Embodiment>

7 is a flowchart showing an operation procedure of the information processing apparatus according to the first embodiment, and FIG. 8 is a view for explaining, as an example, a embedding information generation process in the combining unit 406.

First, the document 400 to be embedded is embedded in the document analysis unit 402 via a document input unit 401 such as a scanner 617 (step S701). The document 400 may receive a printed matter from the scanner 617 or the like and bitmap it. In addition, various electronic data may be converted by image processing software or the like to form a bitmap. The various electronic data are stored in respective storage media connected to the hard disk 604, the CD drive 609, the DVD drive 610, the FDD drive 611, and the like in FIG.

Next, the document analysis unit 402 extracts the circumscribed rectangle (character area) of the document 400 input to the document input unit 401 (step S702). In addition, although the circumscribed rectangle of a letter is originally information which shows the area | region which performs character recognition, in the technique of embedding information in a document, or the technique of extracting the embedded information, it represents the character area | region for which embedding operation is an object. Specifically, each pixel value of the document image is projected on the vertical coordinate axis, the blank portion (the portion having no significant pixel) is searched to determine the row, and the row division is performed. Thereafter, the document 400 is projected on a horizontal coordinate axis in units of lines, and a blank portion is searched for and divided into units of characters. This makes it possible to cut out each character from the circumscribed rectangle.

Next, the embedding information 403 to be embedded in the document 400 is input from the embedding information input unit 404 such as the keyboard 614 (step S703). The embedding information 403 may be selected from those stored in the storage device in advance.

Next, an error correction code is generated from the embedding information input from the embedding information input unit 404 (step S704). For example, as shown in FIG. 8, an error correction code 802 is generated from the embedding information 801.

Next, the synthesizing unit 406 generates the synthesizing embedding information added by arranging the synchronization information with the embedding information (step S705). For example, as shown in FIG. 8, the synthetic embedding information 805 is information embedded by arranging the synchronization information 803 in the embedding information 801. When two bits of information are embedded in one character, one block of embedded information (for example, reference numeral 804 in Fig. 8) is composed of one bit of embedding information and one bit of synchronization information. When n bits (n> 1) of information are embedded in one character, one block of embedding information is composed of n-1 bits of embedding information and 1 bit of synchronization information. As a result, one bit of synchronization information can be embedded for each character.

The synchronization information may be any code having a period N (N> 1). In this embodiment, a pseudo noise series is embedded as synchronization information. The synchronization information 803 shown in FIG. 8 represents a pseudo noise series of period 7. As shown in FIG.

Next, one circumscribed rectangle extracted in step S702 is read (step S706), and the embedding section 407 embeds the embedded embedding information in the characters in the circumscribed rectangle (step S707). One block of synthetic embedding information shown in FIG. 8 is embedded in the read circumscribed quadrangle.

9 is an explanatory diagram of the embedding process of the synthetic embedding information in the embedding unit 407. In this process, synthetic embedding information is embedded in a character by using four different types of embedding patterns (here, dot patterns). For example, a character is constituted by dot pattern 0 (reference numeral 900 shown in FIG. 9) to embed the embedded embedding information "00" (in binary representation) into the character (reference numeral 910 shown in FIG. 9). . To embed the composite embedding information "01" in the character, the character is constituted by dot pattern 1 (reference numeral 901 shown in FIG. 9) (reference numeral 911 shown in FIG. 9). To embed the composite embedding information "10" into the character, the character is constituted by dot pattern 2 (reference numeral 902 shown in FIG. 9) (reference numeral 912 shown in FIG. 9). To embed the composite embedding information "11" into the character, the character is constituted by dot pattern 3 (reference numeral 903 shown in FIG. 9) (reference numeral 913 shown in FIG. 9). Further, if the dot pattern is not embedded in the outline of the character, the character itself is easy to recognize, and therefore, it is preferable. In addition, the dot pattern may not be the pattern shown in FIG. 9, as long as it has the same density | concentration and the mutual correlation is low. Although the example using a dot pattern was shown here, even if it is not a dot pattern, it does not matter if it is a embedding system which embeds n bits (n is an integer of 2 or more) in one character. For example, the tone of a character may be changed in multiple steps, or it may use color, a pattern, and a pattern.

Next, it is judged whether or not the circumscribed rectangle of interest is the final circumscribed rectangle in the document 400 (step S708). If it is determined in step S708 that the circumscribed rectangle of interest is not the final circumscribed rectangle, the flow returns to step S706 to read the next circumscribed rectangle. On the other hand, when it is determined in step S708 that it is the final circumscribed rectangle, a document 409 in which the composite embedding information is embedded is generated (step S709). As shown in FIG. 4, the document 409 in which this information is embedded is output from the document output unit 408. In addition, the output from the document output unit 408 can be performed in various forms such as printing on a printer, storage as image data to a storage device, or the like, or transmission from a network or the like to another terminal.

10 is a flowchart showing an operation procedure of the information processing apparatus (extraction processing) according to the first embodiment, and FIG. 11 is a concrete example illustrating the synthesis embedding information extraction processing in the synthesis embedding information extraction unit 503. It is a figure for following.

First, a document image is input to the document analysis unit 502 through the document image input unit 501 (step S1001), and after extracting an outline rectangle from the document image, character cutting is performed (step S1002). This process is the same process as the document analysis part 402 of the information processing apparatus which performs the embedding process.

Next, the synthetic embedding information embedded for each character is extracted (step S1003). The synthesis embedding information can be extracted by detecting the embedding pattern (dot pattern) embedded in the circumscribed rectangle by the synthesis embedding information extraction unit 503. In this embodiment, two bits of information are extracted from one circumscribed rectangle. For example, in Fig. 11, the character string "ABC... ", The synthetic embedding information 1101 is extracted, and since the synthetic embedding information" 10 "is extracted from the character" A ", it turns out that embedding information is" 1 ". Next, the separation unit 504 extracts synchronization information from the extracted synthesis embedding information (step S1004). For example, as shown in FIG. 11, the synchronization information 1102 is taken out. This is obtained by arranging one bit from each block of the synthetic embedding information.

Next, the error correction unit 507 compares the synchronization information separated by the separation unit 504 with the synchronization information input by the synchronization information input unit 506 to detect an error location (step S1005). For example, as shown in FIG. 11, the input synchronization information is &quot; 0110100... And the separated synchronization information is &quot; 01100100... ", It can be seen that an error occurs in the third and fourth of the extraction information by comparison between the two.

In addition, in this embodiment, since the synchronization information is represented by a pseudo noise series (PN series), the synchronization error position may be detected by cross-correlating the synchronization information. The pseudo noise series is a series having an autocorrelation function of Paa (k) = 1 (k = 0) and −1 / n (0 <k <n). 12 is an explanatory diagram of an autocorrelation function of a pseudo noise series of a period 7. FIG. In the case of using this autocorrelation function, when no error occurs in the synchronization information, the obtained cross-correlation value is 1 or -1/7. However, when an error occurs in the synchronization information, the cross-correlation value is 1 or-. Since it becomes other than 1/7, an error location can be found easily.

When a synchronization error is detected in step S1005, the flow advances to step S1006. The error correction unit 507 corrects the synchronization information of the detected error point. The types of synchronization error correction include bit insertion, deletion, and inversion. The separated sync information is corrected so that the input sync information matches the separated sync information. As a result, when the side and the room of the character are separated and the circumscribed rectangle is extracted, the bit at the error point is deleted. In addition, when characters and characters are combined to extract an circumscribed rectangle, bits are inserted.

FIG. 13 is a diagram for explaining, by way of example, synchronous error correction processing in the error correction unit 507. As shown in FIG. The character is "ABC", the embedding information is "S", and the synchronization information is "X". However, the letter "B" is recognized as two characters in the extraction of the circumscribed rectangle, and is not a character to be separated, but here, it is assumed that the character "B" is extracted as two characters in the extraction of the circumscribed rectangle. In the reference numeral 1301, when a synchronization error point 1302 is detected, the synchronization error is corrected (reference numeral 1303 shown in FIG. 13). Here, since a one-bit insertion error has occurred, the synchronization information of one bit at the error point is deleted. Next, the position of the embedding information is corrected by synchronization error correction (reference numeral 1304 shown in FIG. 13). By such synchronization error correction processing, synchronization error correction of embedded information is performed.

When the synchronization error correction ends in step S1006, the flow returns to step S1005 to detect the next synchronization error point. On the other hand, when the location of the synchronization error is not detected in step S1005, error correction of the embedding information separated by the separating unit 504 is performed (step S1007). This process is executed by the error correction unit 507 to correct with an error correction code. Next, the embedding information output unit 508 outputs embedding information (step S1008), and the process ends.

In addition, the reliability of decoding may be improved by using the reliability of each received symbol by using the generalized General Minimum Distance Decoding (GMD) method. This reliability is based on the idea that the extraction error was previously determined to be a site where the extraction error is likely to occur. Reliability (for example, R = 1) is added to the extracted embedding information, and error correction of the embedding information is performed based on this reliability R. FIG. When the embedding information bit is corrected for synchronization error, the reliability R may be set low. For example, when the embedding information is error corrected as indicated by R (n) = R (n-1) and R (n) = R (n-1) * 0.8 as the reliability after correction as R (n). The reliability can be set to 80% before correction. In addition, when the font of the character is small, the character area is small and the extraction rate of embedding information deteriorates, so that the reliability of the embedding information and the character area may be linked. Further, the similarity of the dot pattern extracted from the character and the reliability of the embedding information may be linked.

In addition, when a synchronization error is detected, the character position analysis unit 502 may be notified of the error position, and square extraction may be performed again. Here, it demonstrates using the flowchart shown in FIG. In step S1005, when a synchronization error is detected, the character analysis unit 502 may be notified of the error position, and the external rectangle may be extracted again. In addition, description of step S1004 is abbreviate | omitted from step S1001 similar to the process mentioned above. If a synchronization error point is detected in step S1005, the flow returns to step S1002. Next, the circumscribed rectangle is corrected using the positional information of the error point (step S1002), and the extracted composite embedding information of the correction point is reextracted (step S1003). In this way, even when a character truncation error occurs, embedding information can be extracted accurately.

In the present embodiment, an example in which n-1 bits constituting the embedding information 403 and 1 bit constituting the synchronization information are embedded in one character is illustrated, but the present invention is not limited thereto. For example, two bits of synchronization information may be embedded in one character. In other words, it is sufficient that at least one bit of synchronization information is embedded in one character. In the method of generating the embedding embedding information, an example in which one bit constituting the synchronization information is synthesized after n-1 bits constituting the embedding information has been described, but the present invention is not limited thereto. For example, it may be in front of the embedding information or between the embedding information, and may share the location of the synchronization information with the extraction side.

<1st embodiment-modification 1>

In this modification, the study was added so that the synchronization information embedded in the character size could be selected. In addition, since it is the same as that of 1st Embodiment except the step S705 in the embedding information embedding process, description is abbreviate | omitted.

The configuration of the information processing apparatus (embedded processing) according to the present modification is a common configuration (Fig. 4), except that the bit pattern of the first period and the bit pattern of the second period longer than the first period are stored. And a bit pattern storage section. Moreover, the detection part which detects the size of the circumference rectangle of the character of embedding object is provided. If the area of the circumscribed rectangle detected by the detection unit is larger than the preset threshold, the bit pattern of the first period is selected. If the area of the circumscribed rectangle is less than or equal to the preset threshold, the bit pattern of the second period is selected. It has a selection part to make. The bit pattern input unit inputs the bit pattern selected by the selection unit.

Here, the method of selecting synchronization information will be described in detail. FIG. 15 is a flowchart showing the detailed operation procedure of step S705 in the first modified example of the first embodiment, and FIG. 16 and FIG. 17 are explanatory diagrams of a circumscribed square error according to the first modified example.

First, a circumscribed rectangular area of one character is calculated (step S705a). This circumscribed square area can be calculated from the circumscribed square information calculated in step S702. In calculating the area of the circumscribed rectangle, the circumscribed rectangle area may be calculated from only the first character of the document image, or the average of the circumscribed rectangle area of the entire document image may be calculated. In addition, only the first character of each paragraph may be extracted to calculate the average of the circumscribed square area, or the circumscribed square area may be calculated from characters randomly selected from the document images.

Next, it is compared whether the calculated circumscribed square area is larger than an arbitrary threshold value M. The threshold M can be arbitrarily determined by the user in advance. When the circumscribed square area is larger than the threshold M, the synchronization information of a short period (first period) is selected (step S705c). For example, the synchronization information &quot; 0101... &Quot; May be used. This is because, when the area of the circumscribed rectangle is large, only a square extraction error (character "靜" shown in Fig. 16C) in which sides and rooms are divided into two occurs. Such square extraction errors can be easily found even in short periods of synchronization information.

On the other hand, when the area of the circumscribed quadrangle is equal to or less than the threshold M, the synchronization information of a period longer than the first period (second period) is selected (step S705d). This is because, when the area of the circumscribed rectangle is small, as shown in Fig. 17, a square extraction error over a large number of characters is likely to occur. Next, the selected synchronization information is added to the embedding information (step S705e).

In addition, the kind of synchronization information embedded when the embedding information is extracted can be easily determined by executing step S705a.

<2nd embodiment>

In the present embodiment, studies have been added to easily determine whether the input document image is a document image in which embedding information is embedded. In the present embodiment, in the embedding information extraction process, since only the process is partially added to the first embodiment, the common parts are denoted by the common reference numerals, and description thereof is omitted.

2 is a flowchart showing an operation procedure of the information processing apparatus (extraction processing) according to the second embodiment, and FIG. 3 is a flowchart showing a detailed operation procedure of step S1801 according to the second embodiment.

First, the document image is read (step S1001), and the circumscribed rectangle of the read document image is extracted (step S1002). Next, a cross correlation value between the extracted synchronization information and the embedded synchronization information is calculated (step S1801), and it is determined whether or not there is a correct cross correlation value (step S1802). When it is determined in step S1802 that there is a correct cross correlation value, it is determined that embedding information is embedded in the document image, and the embedding information is extracted in the same procedure as in the first embodiment. On the other hand, when it is determined in step S1802 that there is no correct cross correlation value, it is determined that embedding information is not embedded in the document image, and the processing of embedding information extraction ends. In addition, in this embodiment, when it is determined that at least one cross-correlation value is correct, it is determined that embedding information is embedded in the document image.

Here, the calculation procedure of the cross correlation value in step S1801 is demonstrated using FIG. First, a continuous circumscribed rectangle is taken out (step S1801a). The number of circumscribed quadrangulars to be taken out is, for example, twice the period of the minimum synchronization information. In addition, you may take out a circumscribed rectangle from arbitrary places of a document image.

Next, the synchronization information is extracted from the extracted circumscribed rectangle (step S1801b), and the cross correlation value between the extracted synchronization information and embedded synchronization information is calculated (step S1801c). In addition, since the pseudo noise series is embedded in the document image in which the embedding information is embedded, the cross-correlation value in the correct case is 1 or -1 / N.

<Other embodiments>

An object of the present invention is to supply a recording medium (or a storage medium) on which a program code of software for realizing the functions of the above embodiments is provided to a device, and the computer of the device reads and executes the program code stored in the recording medium. It is also feasible. In addition, the computer includes a CPU and an MPU. In this case, the program code (computer program) read out from the recording medium itself realizes the functions of the above-described embodiments, and the recording medium (computer readable storage medium) on which the program code is recorded constitutes the present invention. .

Moreover, based on the instruction | indication of the program code which the computer read out, the operating system OS etc. which are running on the computer etc. perform a part or all of actual process, and the function of the above-mentioned embodiment is also implemented. .

The program code read out from the recording medium is also written into a memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer. Subsequently, the function of the above-described embodiment is also realized by the CPU or the like provided in the function expansion card, the function expansion unit, or the like executing the part or all of the actual processing based on the instruction of the program code.

When the present invention is applied to the recording medium, the program code corresponding to the flowchart described above is stored in the recording medium.

In addition, although the error correction code was added to the synthesis embedding information in the above-described embodiment, it is not essential to add the error correction code in the present invention.

While various embodiments in accordance with the present invention have been presented and described, it should be understood that modifications and variations can be made without departing from the scope of the present invention. Accordingly, it is not intended to be limited to the details set forth and described herein, but is to cover all modifications and changes as come within the scope of the appended claims.

1A to 1D are explanatory diagrams of a conventional circumscribed rectangular extraction process.

2 is a flowchart showing an operation procedure of an information processing apparatus (extraction processing) according to the second embodiment.

3 is a flowchart showing a detailed operation procedure of step S1801 according to the second embodiment.

4 is a schematic configuration diagram of an information processing apparatus (embedded processing) according to one embodiment of the present invention.

5 is a schematic configuration diagram of an information processing device (extraction process) according to an embodiment of the present invention.

6 is an electrical configuration diagram of an information processing device according to one embodiment of the present invention.

FIG. 7 is a flowchart showing an operation procedure of an information processing apparatus (embedded processing) according to the first embodiment. FIG.

8 is a diagram for explaining, by way of example, a synthesis process in the synthesis unit 406.

9 is a diagram for explaining the embedding process of the synthetic embedding information in the embedding unit 407.

10 is a flowchart showing an operation procedure of an information processing apparatus (extraction processing) according to the first embodiment.

11 is a diagram for explaining, by way of example, extraction processing of synthesis embedding information in the synthesis embedding information extraction unit 503;

12 is an explanatory diagram of an autocorrelation function of a pseudo noise series in a period 7. FIG.

Fig. 13 is a diagram for explaining, by way of example, synchronization error correction processing in the control unit 507;

14 is a flowchart showing an operation procedure of an information processing apparatus (extraction processing) according to the first embodiment.

Fig. 15 is a flowchart showing the detailed operation procedure of step S705 according to the modification 1 of the first embodiment.

16A to 16D are explanatory diagrams of a circumscribed square error according to Modification Example 1 of the first embodiment.

17 is an explanatory diagram of a circumscribed square error in Modification Example 1 of the first embodiment;

<Explanation of symbols for the main parts of the drawings>

601: Computer

602 CPU

603: main memory

604: HDD

605: Video Controller

606: monitor

607: Bus

608: Printer Interface

609: CD drive

610: DVD Drive

611: FDD Drive

612: input interface

613: Mouse

614: keyboard

615: Scanner Interface

616: Printer

617: Scanner

618: touch panel interface

619: touch panel

Claims (9)

An information processing apparatus that embeds n-bit information (n is an integer of 2 or more) in each character in a document, Document input means for inputting a document composed of characters; Embedding information input means for inputting embedding information to be embedded in the document; Synchronization information input means configured to input synchronization information composed of a plurality of bits and composed of a preset bit pattern; Synthesizing means for generating synthesized embedding information by synthesizing bits constituting the input embedding information and bits constituting the synchronization information; Embedding means for embedding the synthetic embedding information generated by the synthesizing means into each character in a document input by the document input means, and outputting the document after embedding; And The embedding means embeds at least one bit of synchronization information in each character. The method of claim 1, The embedding means, Storage means for storing 2 ⁿ embedded patterns; Mask means for selecting any one of the embedding patterns stored in said storage means and masking a character image in the circumscribed rectangle of the character to be embedded, in accordance with the value of n bits in said composite embedding information generated by said synthesizing means. An information processing apparatus comprising: The method of claim 1, Bit pattern storage means for storing the bit pattern of the first period and the bit pattern of the second period longer than the first period; Detection means for detecting the size of the circumscribed rectangle of the character to be embedded; If the area of the circumscribed rectangle detected by the detection means is larger than a preset threshold value, the bit pattern of the first period is selected, and if the area of the circumscribed rectangle is less than or equal to the preset threshold value, Selecting means for selecting a bit pattern; Bit pattern input means for inputting the bit pattern selected by the selection means An information processing apparatus further comprising: a. The method of claim 1, And error correction information adding means for adding error correction information to the embedding information input by the embedding information input means, And the synthesizing means synthesizes the addition result of the error correction information added by the error correction information adding means and the synchronization information input by the synchronization information input means. An information processing apparatus for extracting information from a document image in which n bits (n is an integer of 2 or more) is embedded in each character in the document image, and at least one bit among the n bits is embedded as synchronization information, Document image input means for inputting a document image; Synthetic embedding information extracting means for obtaining an circumscribed rectangle of each character in the input document image and extracting information embedded in the characters in the circumscribed rectangle; Separation means for separating the synthesis embedding information extracted by the synthesis embedding information extraction means into synchronization information and embedding information; Synchronization information input means for inputting synchronization information; By comparing the synchronous information separated by the separating means with the synchronous information input by the synchronous information input means, an extraction error of the synthetic embedding information extracting means is determined, and when it is determined that there is an extraction error, the separation is performed. Correction means for correcting the composite embedded information such that the synchronization information separated by the means coincides with the synchronization information input by the input means. An information processing apparatus, comprising: a. The method of claim 5, The synchronization information inputted by the synchronization information input means is an information processing apparatus, characterized in that a pseudo noise series. An information processing method in which n bits (n is an integer of 2 or more) are embedded in each character in a document. A document input process of inputting a document composed of characters, A landfill information input process of inputting landfill information to be embedded in the document; A synchronization information input step of inputting synchronization information consisting of a plurality of bits and consisting of a preset bit pattern, A synthesizing step of generating synthetic embedding information by synthesizing bits constituting the input embedding information and bits constituting the synchronization information; A embedding step of embedding the synthetic embedding information generated in the synthesizing step into each character in the document input in the document input step and outputting the document after embedding; And In the embedding step, at least one bit of synchronization information is embedded in each character. An information processing method for extracting information from a document image in which n bits (n is an integer of 2 or more) is embedded in each character in the document image, and at least one bit of the n bits is embedded as synchronization information. A document image input step of inputting a document image, A synthetic embedding information extraction step of obtaining a circumscribed rectangle of each character in the input document image and extracting information embedded in the characters in the circumscribed rectangle; A separation step of separating the synthesis embedding information extracted in the synthesis embedding information extraction process into synchronization information and embedding information; A synchronization information input step of inputting synchronization information; By comparing the synchronization information separated in the separation step with the synchronization information input in the synchronization information input step, an extraction error of the synthesis embedding information extraction step is determined to determine that there is an extraction error. A correction step of correcting the synthesis embedding information so that the synchronized information obtained and the synchronization information input in the input process coincide; An information processing method comprising: A computer readable storage medium storing a computer program for executing each of the steps of claim 7 or 8.

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