JP5809212B2 - Multi-information embedding apparatus and method, multi-information reading apparatus and method, and multi-information print medium - Google Patents

Description

  The present invention relates to a multi-information embedding apparatus and method, a multi-information reading apparatus and method, and a multi-information print medium.

  In recent years, paper documents are rapidly evolving from electronic to digital. However, paper media have features such as convenience, intuition, evidence, and low cost. It cannot be denied that it will survive.

  In addition, when copying or copying a document on which characters or images are printed, the reproducibility and reproduction speed (copying speed) of the document have been the main development targets so far. Thus, it has been proposed to add value to an original printed document that is a copy object.

Proposed added value includes the following.
(1) Character floating This is a function to raise characters such as “copy” and “COPY” on a copy by adding a background pattern having a character floating function to a printed document as the background of the document. . The background pattern having the character lifting function can be created by, for example, making dots larger than other background patterns.

(2) Prohibition of copying By adding a copy-forgery-inhibited pattern indicating the prohibition of copying to a confidential document, the copying machine stops or a black (white) document is output as a copy, and normal This function prohibits the output of duplicates.

(3) Tracking When a background pattern embedded with tracking information is added to a printed document as the background of the document, the printed document is read by the scanner, and the machine used for printing is printed. This is a function that can display the date, date of printing, document contents, and the like.

(4) Automatic transmission For a printed document, address information of the other party to whom the printed document is to be transmitted is embedded in the document as a background pattern. This function allows the contents of the printed document to be transmitted directly to the other party by reading the printed document with a scanner.

(5) Concealment of confidential documents Encrypt document information that you want to keep confidential, and embed it in another printable document. This printed document can be read by entering a personal identification number without knowing the “information to be kept secret”. This is a function of preventing leakage of confidential document information.

(6) Automatic reading function The contents of the document to be printed are embedded in the printed document as an electronic file. In other words, digital information is embedded in analog information. This function allows the contents of the document to be directly stored in the computer as electronic data by reading the document with a scanner.

  Among the above-mentioned added values, for example, “copying prohibition”, for example, describes that “marking”, which is an additional specific graphic element, is added in advance to a document considered to require confidentiality. . This “marking” is an element that can distinguish a confidential document from a normal document. Specifically, black dots or inclined line segments are used as markings for the background of the document image, and the density of these graphics is used to determine whether the document is a confidential document or a normal document.

  Also, with regard to “character lifting”, when the printed document is copied, the dots of the characters that are raised (characters such as copying and COPY) are made larger than the dots of other portions. It is known to raise letters.

Japanese National Patent Publication No. 11-509995

  However, in the prior art, only one of the plurality of added values described above is added to the print document, and none of the plurality of added values is added to the print document. In particular, there has been no “text floating function” for easily recognizing a copy and other functions added to a printed document.

  The present invention has been made in view of such circumstances, and it is possible to add at least one of the above-described functions such as copy prohibition and tracking to a printed document in addition to a character lifting function. It is an object of the present invention to provide a multi-information embedding apparatus and method, a multi-information reading apparatus and method capable of reading a multi-information print medium in which multi-information is embedded, and a multi-information print medium.

A multi-information embedding device according to claim 1 of the present invention is a multi-information embedding device comprising an input unit, an embedding unit, and an output unit,
The input unit has means for inputting desired information to be embedded, and acquiring print image data for embedding the information,
The embedded portion is
A small shape formed by combining a plurality of halftone dots of the same gradation obtained by printing a region where a plurality of small print dots having a predetermined resolution or more can be printed as halftone dots and printing two or more print dots in one halftone dot. By repeatedly arranging the pattern on the printing paper surface , forming a tint block data for creating a tint block printed as a repeated pattern that is difficult to visually recognize the pattern ,
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern data is divided into the two dots in the halftone dots so that a set of the two or more print dots in the halftone dots becomes a large dot having the predetermined resolution or less. As a halftone dot group composed of floating dot patterns in which the above printed dots are arranged, the halftone dots other than the halftone dot group of the floating dot pattern are arranged at positions overlapping with the printed image area. A halftone dot group of subsidence dot patterns in which the two or more print dots are arranged in the halftone dot so that the two or more print dots in the dot become small dots of the predetermined resolution or more, and the floating the dot groups raised dot patterns arranged in the shape of the desired character, the desired character is lifted as the background of the previous SL printed image when reading the background pattern at the predetermined resolution below the image reading apparatus To, embedded characters floating in the background pattern data,
Each halftone dot unit can be obtained by centrally arranging or distributing the plurality of print dots printed in the halftone dots without changing the position and gradation of each halftone dot of the halftone dot group of the floating character dot pattern. in "1" or "0" information bits fill the write-capable information matrix provided for, provided no void area dots printed around the information matrix, so as to surround the information matrix to the outside of said void region Information description state information and position reference information are arranged, and the tint block data is formed by a repetitive pattern in which the information matrix, the gap area, the description state information, and the position information are a unit.
Functional information for executing at least one of a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy- forgery-inhibited pattern data, and the position reference embedded information identifying the position of the functional information embedded in the information matrix as information, embedding the information indicating whether the function information on each halftone dot of the information matrix as the information describing the state information is embedded,
The output unit may be overprinted data of the tint block data and the print image.

  In the multi-information embedding apparatus according to the present invention, a background pattern having a character lifting function is configured by a pattern array including an information matrix, and additional information is embedded in the background pattern. For this reason, at least one of a copy prohibiting function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function can be added to the print medium in addition to the character lifting function. In other words, not only a single function but also a plurality of functions can be given to the print medium according to the purpose, and convenience and evidence of information transmission using a paper medium can be improved.

  It is preferable that the pattern arrangement has a pattern of the same shape repeated. In this case, by using a copy-forgery-inhibited pattern having a repeated pattern, even if a low-precision printer of about 100 dpi is used, the background pattern embedded in the printed image can be made inconspicuous due to human visual characteristics.

  It is preferable that the pattern array further includes information description state information indicating a description possibility of information of each row and each column of the information matrix. By providing such information description state information, even when a part of the information description pattern overlaps the print image, the remaining part can be used for the description of the information, and the amount of information that can be described is increased. can do. That is, information description can be performed by effectively using the gap portion of the print image.

  The screen code has gradation characteristics of halftone dots of the printing screen, spacing characteristics of halftone dots of the printing screen, or arrangement characteristics of halftone dots of the printing screen. The appearance of the printed image in which multi-information is embedded has a good feature.

  The geometric information embedding code capable of recognizing the pattern includes concentration and dispersion of a plurality of small dots, different positions of halftone dots, different directions of halftone dots, different sizes of halftone dots, The dot pattern is configured by at least one geometric arrangement method including different numbers. According to such a configuration, it is possible to describe multi-information, and there is a feature that it is easy to merge with a ground pattern composed of repeated patterns.

  The pattern recognizable physical information embedding code includes different modulation methods of halftone dots, different frequency components of halftone dots, different phase modulation of halftone dots, and different gradation values of halftone dots. At least, the dot pattern is formed by one physical arrangement method. According to such a configuration, it is possible to describe multi-information, and there is a feature that it is easy to merge with a ground pattern composed of repeated patterns.

A multi-information embedding method according to claim 4 of the present invention is a multi-information embedding method comprising an input step, an embedding step, and an output step,
The input step inputs desired information to be embedded, obtains print image data for embedding the information ,
The buried step,
A small dot formed by combining a plurality of halftone dots of the same gradation obtained by printing a plurality of small print dots having a predetermined resolution or more and having two or more print dots printed in one halftone dot. By repeatedly placing the pattern of the shape on the printing paper surface, forming a copy-forgery-inhibited pattern data for creating a copy-forgery-inhibited pattern printed as a repeated pattern that is difficult to visually recognize the pattern,
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern data is divided into the two dots in the halftone dots so that a set of the two or more print dots in the halftone dots becomes a large dot having the predetermined resolution or less. As a halftone dot group composed of floating dot patterns in which the above printed dots are arranged, the halftone dots other than the halftone dot group of the floating dot pattern are arranged at positions overlapping with the printed image area. A halftone dot group of subsidence dot patterns in which the two or more print dots are arranged in the halftone dot so that the two or more print dots in the dot become small dots of the predetermined resolution or more, and the floating When the halftone dot group of the raised dot pattern is arranged in a desired character shape and the background pattern is read by the image reading device having the predetermined resolution or lower, the desired character is lifted as the background of the printed image. To, embedded characters floating in the background pattern data,
Each halftone dot unit can be obtained by centrally arranging or distributing the plurality of print dots printed in the halftone dots without changing the position and gradation of each halftone dot of the halftone dot group of the floating character dot pattern. Provides an information matrix that can embed information bits of “1” or “0”, provide a void area without dot printing around the information matrix, and describe the information so as to surround the information matrix outside the void area Arranging the state information and the position reference information, forming the copy-forgery-inhibited pattern data by a repetitive pattern having the information matrix, the gap area, the description state information, and the position information as a unit;
Functional information for executing at least one of a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy-forgery-inhibited pattern data, and the position reference Embedding information specifying the position of the functional information embedded in the information matrix as information, and embedding information indicating whether the functional information is embedded in each halftone dot of the information matrix as the information description state information,
It said output step is characterized by printing overlapping the data of the tint block data and the print image.

  In the multi-information embedding method of the present invention, a background pattern having a character lifting function is configured by a pattern array including an information matrix, and additional information is embedded in the background pattern. For this reason, at least one of a copy prohibiting function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function can be added to the print medium in addition to the character lifting function. That is, not only a single function but also a plurality of functions can be given to the print medium according to the purpose, and the convenience and usefulness of information transmission using a paper medium can be improved.

It is preferable that the pattern arrangement has a pattern of the same shape repeated.
It is preferable that the pattern array further includes information description information indicating a description possibility of information of each row and each column of the information matrix.

  The screen code has gradation characteristics of halftone dots of the printing screen, spacing characteristics of halftone dots of the printing screen, and arrangement characteristics of halftone dots of the printing screen. The appearance of the printed image in which multi-information is embedded has a good feature.

  The geometric information embedding code capable of recognizing the pattern includes concentration and dispersion of a plurality of small dots, different positions of halftone dots, different directions of halftone dots, different sizes of halftone dots, The dot pattern is configured by at least one geometric arrangement method including different numbers. According to such a configuration, it is possible to describe multi-information, and there is a feature that it is easy to merge with a ground pattern composed of repeated patterns.

  The pattern recognizable physical information embedding code includes different modulation methods of halftone dots, different frequency components of halftone dots, different phase modulation of halftone dots, and different gradation values of halftone dots. At least, the dot pattern is formed by one physical arrangement method. According to such a configuration, it is possible to describe multi-information, and there is a feature that it is easy to merge with a ground pattern composed of repeated patterns.

In the multi-information embedding medium according to claim 7 of the present invention, a halftone dot is an area where a plurality of small print dots having a predetermined resolution or higher can be printed, and two or more print dots are printed in one halftone dot. It has a copy-forgery-inhibited pattern printed as a repetitive pattern that is difficult to visually recognize by repeatedly placing a small-shaped pattern formed by combining a plurality of halftone dots of the same gradation on the printing paper surface. ,
The tint block is
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern is used to print the two or more dots in the halftone dots so that a set of the two or more print dots in the halftone dots is a large dot having the predetermined resolution or less. As a halftone dot group composed of a floating dot pattern in which dots are arranged, the halftone dot group other than the halftone dot group of the floating dot pattern is arranged at a position overlapping a desired print image area. The floating dot is constituted by a halftone dot group of a submerged dot pattern in which the two or more print dots are arranged in the halftone dots so that the two or more print dots are small dots having the predetermined resolution or more. By arranging the halftone dot group of the pattern in the shape of a desired character, when the copy-forgery-inhibited pattern is read by the image reading device having the predetermined resolution or less, the desired character is raised as a background of the desired print image. It said and character is embedded floating in the background pattern to so that,
Further, the tint block is formed by concentrating or distributing a plurality of the printing dots printed in the halftone dots without changing the position and gradation of each halftone dot group of the floating dot pattern, Each halftone dot has an information matrix in which an information bit of “1” or “0” can be embedded, a void area without dot printing is provided around the information matrix, and the information matrix is placed outside the void area. The information description state information and the position reference information are arranged so as to surround the information matrix, the gap area, the description state information, and the position information, and are configured by a repetitive pattern.
Functional information for executing at least one desired function among a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy-forgery-inhibited pattern. Whether information for specifying the position of the function information embedded in the information matrix is embedded as the position reference information, and the function information is embedded in each halftone dot of the information matrix as the information description state information. Information is embedded,
The copy-forgery-inhibited pattern in which the various data is embedded and the desired print image are overlaid and printed .

A multi-information reader according to claim 10 of the present invention is an apparatus for reading multi-information recorded on the tint block from the multi-information print medium according to any one of claims 7 to 9,
An image input unit, a recognition unit, and a registration unit;
The image input unit reads a multi-information print medium as image data from an image sensor,
The recognizing unit reads the functional information from the information bits recorded in the halftone dots of the raised dot pattern of the image data;
The registration unit stores the functional information read by the recognition unit in a memory or other recording medium .

A multi-information print medium according to an eleventh aspect of the present invention is a multi-information print medium output by the multi-information embedding device according to the first aspect,
By using human visual characteristics and arranging small patterns of the same shape repeatedly, a ground pattern that can embed multi information is constructed,
Geometrical / physical that can recognize the necessary multi-information with multiple functions among copy-inhibiting function, tracking function, automatic transmission function, confidential information concealing function, and automatic reading function as well as the character lifting function. Converted into a screen code,
An information matrix composed of a plurality of halftone dots of the configured background pattern and a position for recognizing the position of each halftone dot of the information matrix by repeatedly arranging the converted screen code on the small pattern of the same shape. As a pattern arrangement including reference information, error correction (detection) information, and information description state information, a new background pattern that is configured and image data to be printed are output and overlapped.

Note that definitions of terms such as “halftone dots” used in this specification are as follows.
(1) “Pixel” is the smallest unit constituting an image, “Halftone” is the smallest unit constituting an image, ie, the smallest unit of a screen corresponding to a pixel, and “halftone dot” is a halftone dot The minimum unit of dots to be printed, and “printing dot” is the minimum dot (1 inch / dpi) that can be printed with respect to the printing accuracy (dpi) of the printing equipment. A halftone dot is composed of printing dots.

(2) “Geometric information embedding code” refers to an arrangement of dot patterns constituting an identifier, an arrangement of different positions, an arrangement in different directions, an arrangement of different shapes, different dot sizes, This is a geometric dot pattern including the number of different halftone dots, the concentration and dispersion of dots, and the like.

(3) “Physical information embedding code” refers to the arrangement of different modulation schemes, phase modulation schemes, different transport directions, different frequency components, different gradation values, etc., relative to the arrangement of the dot pattern constituting the identifier. That is, a physical dot pattern including

(4) “Gradation characteristic of screen halftone dot” means that the gradation characteristic of the screen halftone dot, that is, the total number of dots in the screen halftone dot is configured similarly.

(5) “Different modulation method” is an amplitude modulation screen, that is, an AM screen, which represents the gradation of a screen halftone dot according to the size of the halftone dot, depending on the number of dots in the halftone dot. A method for expressing the gradation of the screen halftone is a frequency modulation screen, that is, an FM screen. In this method, information can be described by different modulation schemes for halftone dots of the same gradation.

  The dot pattern configuration method based on different modulation methods has the same meaning as the dot pattern configuration method based on a plurality of frequency components, and the actual dot pattern arrangement is the same. That is, the AM screen dot pattern can be rephrased as a low-frequency dot pattern, and the FM screen dot pattern can be rephrased as a high-frequency dot pattern.

  A dot pattern configuration method using a different modulation method has the same meaning as a dot pattern configuration method using a plurality of dots of different gradations, and the actual dot pattern arrangement is the same. That is, since the dot pattern of the AM screen has a plurality of small dots concentrated, the gradation value of the dots of the AM screen is large. On the other hand, since the dot pattern of the FM screen has a plurality of small dots dispersedly arranged, the gradation value of each dot of the FM screen is small. For the reasons described above, the AM screen dot pattern can be rephrased as one dot pattern having a large gradation value, and the FM screen dot pattern can be rephrased as a dot pattern composed of a plurality of small gradation dots. it can.

  According to the multi-information embedding apparatus and method of the present invention, it is possible to add at least one of the above-described functions such as copy prohibition and tracking to the printed document, in addition to the character floating function. Also, according to the multi-information reading apparatus and method of the present invention, it is possible to read a multi-information print medium in which such multi-information is embedded. Furthermore, according to the multi-information print medium of the present invention, it is possible to add at least one of the above-described functions such as copy prohibition and tracking to the print document, in addition to the character floating function.

It is a conceptual diagram of the multi information embedding device of the present invention. It is a conceptual diagram of the multi information reader of this invention. It is a figure which shows an example of the tint block which consists of a repeating pattern used in this invention. It is a figure which shows an example of the floating dot pattern showing information "1". It is a figure which shows an example of the floating dot pattern showing information "0". It is a figure which shows the other example of the floating dot pattern showing information "0". It is a figure which shows an example of the dot pattern which sinks. It is a figure which shows an example of an information pattern group. (A) is an example of a copy prohibited dot pattern, and (b) is a diagram showing an example of a copyable dot pattern. (A) is another example of a copy-prohibited dot pattern, and (b) is a diagram showing another example of a copyable dot pattern. It is a figure which shows an example of the document in which the information of the several objective was embedded. It is a figure which shows the copy which copied the document shown by FIG. It is a figure which shows the structural example of the screen code which makes the dot number of a halftone dot one. It is a figure which shows the example of application of the multi-information reader of this invention.

Hereinafter, embodiments of a multi-information embedding device and method, a multi-information reading device and method, and a multi-information print medium according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a conceptual diagram of a multi-information embedding apparatus according to the present invention. The multi-information embedding apparatus of the present invention is an apparatus that embeds at least one of a copy-inhibiting function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function in a printed image by using a tint block as well as a character lifting function. And includes an input unit 1, an embedding unit 2, and an output unit 3. In a conventional apparatus or method, only a single function can be added to a printed image, such as only a character lifting function if the character lifting function is used, and only a copy prohibiting function if the copy prohibiting function is used. In the present invention, a plurality of functions can be given to a print medium by using an information matrix to be described later and a screen code having screen characteristics.

  The input unit 1 has means for inputting additional information data to be embedded and acquiring a print image as an embedded medium.

The embedding unit 2 adds the additional information data to be embedded inputted by the input unit 1 to the gradation characteristics of the halftone dots of the printing screen, the spacing characteristics of the halftone dots of the printing screen, and the arrangement of the halftone dots of the printing screen. Means for converting into a screen code that is a pattern-recognizable geometrical or physical information embedding code having at least one of the characteristics.
Here, different dot patterns (different information can be described) by using “tone characteristics of printing screen halftones” that the gradation values are the same, that is, the patterns are microscopically different but look the same. Can look the same. Also, regarding the relationship between the halftone dots and the spacing between adjacent halftone dots, the smaller the halftone dots and the larger the halftone dot intervals, the more the screen code affects the printed image in which information is embedded. By using the “halftone dot spacing characteristic” that is small, it is possible to reduce the influence of the copy-forgery-inhibited pattern embedded with the additional information on the printed image. That is, when the halftone dot interval is larger than the halftone dot size, the randomness caused by the change of the embedded information is small. Further, the use of the “print screen halftone dot arrangement characteristic” can suppress the printing moire phenomenon. Hereinafter, the moire phenomenon will be described in detail.

First, the printing moire is an interference pattern that occurs when a plurality of regular patterns overlap. Here, the printing moire phenomenon that occurs due to the difference between the number of lines of the dot pattern and the number of lines of printing by a printer or a printing machine will be considered.
When the number of parallel lines is Ln, the frequency Pm of moire when any two parallel lines of the line numbers Ln1 and Ln2 overlap can be derived by the following equation (1).

  Further, the moire cycle Tm is the reciprocal of the moire frequency as shown in the following equation (2).

From equation (2), the moire frequency must be zero in order to prevent the moire phenomenon from occurring when two parallel line patterns are overlapped. That is, if the difference in the number of lines is very small, the moire frequency is low, so the moire cycle becomes long, and as a result, the moire becomes less noticeable.
It has also been found that by rotating the two sets of gratings at an angle of 45 degrees, there is no stable moire.

  In this embodiment, the use of a 45 degree dot pattern arrangement alleviates the occurrence of printing moire even if the printing machine has low accuracy.

In addition, the embedding unit 2 has a dot pattern including a screen code array configuration including an information matrix composed of a plurality of halftone dots, position reference information for recognizing the positions of the halftone dots of the information matrix, and error correction information. And a means for constructing a new print image by arranging it on the print image. The arrangement of the screen code will be described later.
The output unit 3 is configured to output the new print image.

    FIG. 2 is a conceptual diagram of the multi-information reader according to the present invention. The multi-information reading device of the present invention is a device for reading the additional information in the multi-print medium in which the additional information is embedded in the print image by the multi-information embedding device shown in FIG. And a recognition unit 5 and a registration unit 6.

The image input unit 4 reads, as image data, a multi-print medium in which additional information is embedded in a print image with a background pattern from a normal image sensor (not shown).
The recognizing unit has means for detecting a position of a screen code in a dot pattern constituting the tint block and recognizing a code value of the screen code, and the registering unit stores the recognized screen code in a memory , Means for registering in at least one recording medium among a hard disk, a CD-ROM, and a network server.

  Then, based on the code value of the read screen code, functions such as “copying off” and “tracking” as well as the above-mentioned “character floating” are applied to a copy output from the output unit (printer) of the copying machine. It is executed against.

  In this embodiment, the tint block is configured by repeatedly arranging small patterns of the same shape as shown in FIG. By using a copy-forgery-inhibited pattern having such a repetitive pattern, even if a low-precision printer of about 100 dpi is used, the background pattern embedded in the printed image can be made inconspicuous due to human visual characteristics. That is, when a pattern having the same shape is repeatedly arranged, the tint block is formed by utilizing the human visual characteristic that the judgment of the dots becomes dull when viewed as a whole even if the dots themselves are somewhat large. As a result, it is possible to suppress the occurrence of a sense of incongruity with the printed material in which the additional information is embedded. Note that the background pattern shown in FIG. 3 is merely an example, and other than this, a background pattern composed of various types of repeated patterns can be employed.

  FIG. 4 shows an example of a raised dot pattern representing information “1”. In the example shown in FIG. 4, a screen halftone of 45 degree rotation format is configured using 5 × 5 = 25 printing dots. The pattern shown in FIG. 8 to be described later is the same, but the occurrence of the moire phenomenon described above can be suppressed by rotating the matrix dot pattern by 45 degrees. The system in which the raised dot pattern representing the information “1” indicates the gradation of the screen halftone dot according to the size of the halftone dot with respect to the print screen halftone is an amplitude modulation screen, that is, an AM screen. A method of expressing the tone of the screen halftone by the number is a frequency modulation screen, that is, an FM screen. Information can be described by different modulation methods for the same halftone dot.

  The dot pattern configuration method based on different modulation methods has the same meaning as the dot pattern configuration method based on a plurality of frequency components, and the actual dot pattern arrangement is the same. That is, the AM screen dot pattern can be rephrased as a low frequency dot pattern, and the FM screen dot pattern can be rephrased as a high frequency dot pattern.

  A dot pattern configuration method using a different modulation method has the same meaning as a dot pattern configuration method using a plurality of dots of different gradations, and the actual dot pattern arrangement is the same. That is, since the dot pattern of the AM screen has a plurality of small dots concentrated, the gradation value of the dots of the AM screen is large. On the other hand, since the dot pattern of the FM screen has a plurality of small dots dispersedly arranged, the gradation value of each dot of the FM screen is small. For the reasons described above, the AM screen dot pattern can be rephrased as one dot pattern having a large gradation value, and the FM screen dot pattern can be rephrased as a dot pattern composed of a plurality of small gradation dots. it can.

FIG. 5 shows an example of a raised dot pattern representing information “0”. In the example shown in FIG. 5, a screen halftone of 45 degree rotation format is configured using a distributed arrangement of four 2 × 3 = 6 printing dots.
FIG. 6 shows another example of a raised dot pattern representing information “0”. In the example shown in FIG. 6, a substantially half-shaped screen halftone dot is formed using a dispersion arrangement of twelve 1 × 2 print dots and four halftone dots.

  FIG. 7 shows an example of a sinking dot pattern. In this example, 23 print dots are arranged at substantially equal intervals to form a screen halftone dot of 45 degree rotation type.

  FIG. 8 is a diagram showing an example of a screen code arrangement in the present invention. A tint block is formed by repeatedly arranging such arrays. In FIG. 8, 11 is a halftone dot representing information “1”, and 12 is a halftone dot representing information “0”. 13 is an information matrix in which 9 × 9 = 45 halftone dots are arranged in a 45-degree rotation format in a matrix, 14 is a position reference line, 15 is a parity check line, and 16 is an information description. It is a status line. 17 is a position reference check string, 18 is a parity check string, and 16 is an information description state string. 24, 25, and 26 are a position reference line, a parity check line, and an information description state line, respectively, of the information matrix 23 (represented by a two-dot chain line) that exists in the lower right of the information matrix 13 in FIG. is there. Reference numerals 37, 38, and 39 denote a position reference line, a parity check line, and an information description state line, respectively, of the information matrix 33 (represented by a two-dot chain line) that exists in the lower left of the information matrix 13 in FIG. .

  In the pattern arrangement shown in FIG. 8, each halftone dot of the information matrix 13 represents information “1” or information “0”, and each halftone dot of the information matrix 13 using the position reference row 14 or the position reference column 17. The position of the point can be recognized. As a result, detailed position information can be described, so that the capacity for describing information for the information matrix can be increased, and the recognition accuracy can be increased.

  When the number of halftone dots of information “1” existing in the corresponding row or column of the information matrix 13 becomes an even number, the value of the halftone dot of the corresponding parity check row 15 or parity check column 18 is set to zero. Conversely, when the number of halftone dots of the information “1” existing in the corresponding row or column of the information matrix 13 becomes an odd number, the halftone value of the corresponding parity check row 15 or parity check column 18 is set to 1. By installing the parity check row 15 or the parity check column 18 as described above, it is possible to easily find an error in information description caused by dirt or breakage of paper as a print medium and correct the error. When accurate information is obtained using the parity check row 15 or the parity check column 18, a correct recognition result can be obtained without using “error correction” to be described later, so that the processing efficiency can be improved.

  In addition, the background pattern in which the additional information in the present invention is embedded is mixed with the print image that is originally intended to be printed. For this reason, as a result of part of the rows or columns of the information matrix 13 overlapping the print image, description of information may become impossible. In this case, the corresponding halftone dot in the information description state row 16 or the information description state column 19 associated with the row or column of the information matrix 13 is set to “0”, and otherwise, it is set to “1”. In this way, even when a part of the information description pattern overlaps with the print image, the remaining part can be used for describing the information, and the amount of information that can be described can be increased. In order to correct information errors, conventional error correction information can be arranged in the information matrix 13, which ensures that even when two or more errors exist in the same row or column. The error can be corrected. However, since error correction using this error correction information requires a large amount of calculation, there is a disadvantage that the processing efficiency is lowered.

  FIG. 9A shows an example of a copy-prohibited dot pattern, and FIG. 9B shows an example of a copy-capable dot pattern. In the present invention, copy prohibition information can be described using a dot pattern that can describe information. In the example shown in (a) of FIG. 9, copy prohibition information is described by placing an information halftone dot 42 in the middle of two position reference halftone dots 41. In the example shown in FIG. 9B, information that can be copied is described by arranging an information halftone dot 42 one dot above the middle of the two position reference halftone dots 41.

  Normally, if there is no copy prohibition code, it is considered that normal copying is possible, but if it is known that copying is possible at an early stage for a copying machine equipped with a copy prohibition function, recognition of copy prohibition is recognized. By stopping the process, the copy process can be performed earlier. In this embodiment, a dot pattern that describes information that can be copied is used by using a dot pattern that can describe information.

  Note that the example shown in FIG. 9 also has the effect of preventing tampering by changing the position of the middle information halftone dot 42. That is, copying is prohibited by placing the information halftone dot 42 above the middle of the two position reference halftone dots 41, and copying is possible by placing the information halftone dot 42 in the middle of the two position reference halftone dots 41. In this case, there is a possibility that the information halftone dot 42 is recognized as being copyable by illegally adding a dot to the middle of the two position reference halftone dots 41 even though copying is prohibited. However, if the information halftone dot 42 is placed in the middle of the two position reference halftone dots 41 as shown in FIG. 9, if the copy prohibition is made, the copy prohibition is recognized even if another dot is added. The

In the example shown in FIG. 9, information indicating whether copying is prohibited or copying is described by a geometric arrangement method in which the positions of halftone dots are different and directions are different. In addition, information indicating whether copying is prohibited or copying is possible by phase modulation of information halftone dots.

  FIG. 10A shows another example of a copy-prohibited dot pattern, and FIG. 10B shows another example of a copyable dot pattern. In the example shown in (a) of FIG. 10, copy prohibition information is described by placing an information halftone dot 42 in the middle of two position reference halftone dots 41 of 1 × 2 = 2. Further, in the example shown in FIG. 10B, the information halftone dot 42 is dispersed and arranged one dot above and below the middle of the two position reference halftone dots 41. It describes information that can be copied.

  The copy-prohibited dot pattern and the copyable dot pattern shown in FIG. 10 are copy-prohibited depending on the geometrical arrangement such as the concentration and dispersion of halftone dots, the size of different halftone dots, and the number of different halftone dots. Describes whether copying is possible. Whether copying is prohibited or copying can also be described by physical arrangement methods such as different modulation methods, different frequency components, and gradation values of different halftone dots.

FIG. 11 shows an example of a document in which a plurality of pieces of information are embedded. FIG. 12 shows a copy of the document shown in FIG. As shown in FIG. 11, in the present embodiment, small patterns of the same shape are repeatedly arranged. Therefore, even with a resolution of about 100 dpi, the dots constituting the background pattern are not so conspicuous, and the printed image I don't feel uncomfortable. The copy-forgery-inhibited pattern describes information having a character lifting function. When a document on which the copy-forgery-inhibited pattern is formed is copied, as shown in FIG. 12, “COPY” indicating that the document is a copy. The word comes up.
When embedding a large amount of information, it is also possible to form a tint block by using halftone dots of a small pattern all having the same shape as character floating halftone dots, that is, using all halftone dots according to the accuracy of the printing equipment.

  The screen code described above is merely an example, and various types of screen codes can be employed in the present invention. For example, FIG. 13 shows another form of the screen code construction method. In this example, the smaller the number of dots and the smaller the halftone dot size, the less the influence of the embedding result on the printed image. This is a 9-bit multi-bit screen code in which the number of dots in a halftone dot is set to 1 by sharing dots within the information group or by using a dot as an arrangement reference.

  In FIG. 13, reference numeral 1301 denotes an information dot, and reference numeral 1302 denotes a cell in which the information dot 1301 can be arranged. First, information is described by information dots 1301 having different geometric positions. For example, in FIG. 13, a dot arrangement of halftone dots (arrangement indicated by (a); the same applies hereinafter) is set to a multibit value “0”, a dot arrangement of halftone dots is set to a multibit value “1”, and c The dot arrangement of the dot is a multibit value “2”, the dot arrangement of the d halftone dot is a multibit value “3”, the dot arrangement of the e halftone dot is a multibit value “4”, and the dot arrangement of the f halftone dot is The multi-bit value is “5”, the dot arrangement of the g halftone dot is the multi-bit value “6”, the dot arrangement of the halftone dot is the multi-bit value “7”, and the dot arrangement of the i halftone dot is the multi-bit value “8”. " With reference to the example shown in FIG. 13, a multi-bit screen code of a hexadecimal system or more or a 32 system or more with a dot number of halftone dots is formed by arranging various positions of information dots. can do.

  The screen codes a, b, c, d, e, f, g, h, and i shown in FIG. 13 can be regarded as physical dot patterns configured by dot carrier signals of different phase modulation of information dots 1301. it can. It can also be regarded as a physical dot pattern composed of different dynamic centers of gravity.

  The recognition unit for performing the screen code processing in the multi-information reading apparatus of the present invention can be provided in parallel with the conventional copying processing partial circuit 52 in the copying machine as shown in FIG. 14, for example. As shown in FIG. 14, the scanner partial circuit 51 is connected to a conventional copy processing partial circuit 52, and this copy processing partial circuit 52 is connected to a printer partial circuit 53. The screen code processing circuit 54 is arranged in parallel with the copy processing partial circuit 52, and the scanner partial circuit 51 and the printer partial circuit 53 are connected to the screen code processing circuit 54. The advantage of this arrangement is that a screen code processing function can be added to the copying machine without affecting the conventional processing of the copying machine.

DESCRIPTION OF SYMBOLS 1 Input part 2 Embedding part 3 Output part 4 Image input part 5 Recognition part 6 Registration part 11 Halftone dot (information "1")
12 Halftone dot (Information “0”)
13 Information matrix 14 Position reference row 15 Parity check row 16 Information description state row 17 Position reference column 18 Parity check column 19 Information description state column 41 Position reference halftone dot 42 Information halftone dot

Claims (11)

A multi-information embedding device comprising an input unit, an embedding unit, and an output unit,
The input unit has means for inputting desired information to be embedded, and acquiring print image data for embedding the information,
The embedded portion is
A small shape formed by combining a plurality of halftone dots of the same gradation obtained by printing a region where a plurality of small print dots having a predetermined resolution or more can be printed as halftone dots and printing two or more print dots in one halftone dot. By repeatedly arranging the pattern on the printing paper surface , forming a tint block data for creating a tint block printed as a repeated pattern that is difficult to visually recognize the pattern ,
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern data is divided into the two dots in the halftone dots so that a set of the two or more print dots in the halftone dots becomes a large dot having the predetermined resolution or less. As a halftone dot group composed of floating dot patterns in which the above printed dots are arranged, the halftone dots other than the halftone dot group of the floating dot pattern are arranged at positions overlapping with the printed image area. A halftone dot group of subsidence dot patterns in which the two or more print dots are arranged in the halftone dot so that the two or more print dots in the dot become small dots of the predetermined resolution or more, and the floating the dot groups raised dot patterns arranged in the shape of the desired character, the desired character is lifted as the background of the previous SL printed image when reading the background pattern at the predetermined resolution below the image reading apparatus To, embedded characters floating in the background pattern data,
Each halftone dot unit can be obtained by centrally arranging or distributing the plurality of print dots printed in the halftone dots without changing the position and gradation of each halftone dot of the halftone dot group of the floating character dot pattern. in "1" or "0" information bits fill the write-capable information matrix provided for, provided no void area dots printed around the information matrix, so as to surround the information matrix to the outside of said void region Information description state information and position reference information are arranged, and the tint block data is formed by a repetitive pattern in which the information matrix, the gap area, the description state information, and the position information are a unit.
Functional information for executing at least one of a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy- forgery-inhibited pattern data, and the position reference embedded information identifying the position of the functional information embedded in the information matrix as information, embedding the information indicating whether the function information on each halftone dot of the information matrix as the information describing the state information is embedded,
The output unit prints superimposed data of the tint block data and the print image,
A multi-information embedding device characterized by that. The embedding unit does not embed the information bits in an overlapping area where a part of the information matrix of the raised character pattern overlaps the data of the print image, and the information bits are not embedded in the overlapping area. Is written as the description state information, information bits are embedded in a region other than the overlapping region of the information matrix, and information indicating that information bits are embedded in a portion other than the overlapping region is described in the description state multi information embedding apparatus according to claim 1, characterized in that embedded as information. The multi-information embedding apparatus according to claim 1, wherein the embedding unit embeds a dot pattern indicating that copying is prohibited or copying is possible in the repetitive pattern. A multi-information embedding method comprising an input step, an embedding step, and an output step,
The input step inputs desired information to be embedded, obtains print image data for embedding the information,
The embedding step includes
A small dot formed by combining a plurality of halftone dots of the same gradation obtained by printing a plurality of small print dots having a predetermined resolution or more and having two or more print dots printed in one halftone dot. By repeatedly placing the pattern of the shape on the printing paper surface , forming a copy-forgery-inhibited pattern data for creating a copy-forgery-inhibited pattern printed as a repeated pattern that is difficult to visually recognize the pattern ,
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern data is divided into the two dots in the halftone dots so that a set of the two or more print dots in the halftone dots becomes a large dot having the predetermined resolution or less. As a halftone dot group composed of floating dot patterns in which the above printed dots are arranged, the halftone dots other than the halftone dot group of the floating dot pattern are arranged at positions overlapping with the printed image area. A halftone dot group of subsidence dot patterns in which the two or more print dots are arranged in the halftone dot so that the two or more print dots in the dot become small dots of the predetermined resolution or more, and the floating the dot groups raised dot patterns arranged in the shape of the desired character, the desired character is lifted as the background of the previous SL printed image when reading the background pattern at the predetermined resolution below the image reading apparatus To, embedded characters floating in the background pattern data,
Each halftone dot unit can be obtained by centrally arranging or distributing the plurality of print dots printed in the halftone dots without changing the position and gradation of each halftone dot of the halftone dot group of the floating character dot pattern. in "1" or "0" information bits fill the write-capable information matrix provided for, provided no void area dots printed around the information matrix, so as to surround the information matrix to the outside of said void region Information description state information and position reference information are arranged, and the tint block data is formed by a repetitive pattern in which the information matrix, the gap area, the description state information, and the position information are a unit.
Functional information for executing at least one of a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy- forgery-inhibited pattern data, and the position reference embedded information identifying the position of the functional information embedded in the information matrix as information, embedding the information indicating whether the function information on each halftone dot of the information matrix as the information describing the state information is embedded,
In the output step, the copy-forgery-inhibited pattern data and the print image data are overlaid and printed .
And a multi-information embedding method. In the embedding step, the information bit is not embedded in the overlapping area where a part of the information matrix of the floating character pattern overlaps the data of the print image, and the information bit is not embedded in the overlapping area. The information indicating is embedded as the description state information, the information bit is embedded in an area other than the overlapping area of the information matrix, and the information indicating that the information bit is embedded in a part other than the overlapping area is the description state information multi information embedding method according to claim 4, characterized in that embedded as.     6. The multi-information embedding method according to claim 4, wherein the embedding step embeds a dot pattern indicating that copying is prohibited or copying is possible in the pattern. A small shape formed by combining a plurality of halftone dots of the same gradation obtained by printing a region where a plurality of small print dots having a predetermined resolution or more can be printed as halftone dots and printing two or more print dots in one halftone dot. The pattern is printed on the printing paper surface repeatedly, and the pattern is printed as a repeated pattern that is difficult to visually recognize,
The tint block is
A part of the plurality of halftone dots constituting the copy-forgery-inhibited pattern is used to print the two or more dots in the halftone dots so that a set of the two or more print dots in the halftone dots is a large dot having the predetermined resolution or less. As a halftone dot group composed of a floating dot pattern in which dots are arranged, the halftone dot group other than the halftone dot group of the floating dot pattern is arranged at a position overlapping a desired print image area. The floating dot is constituted by a halftone dot group of a submerged dot pattern in which the two or more print dots are arranged in the halftone dots so that the two or more print dots are small dots having the predetermined resolution or more. By arranging the halftone dot group of the pattern in the shape of a desired character, when the copy-forgery-inhibited pattern is read by the image reading device having the predetermined resolution or less, the desired character is raised as a background of the desired print image. It said and character is embedded floating in the background pattern to so that,
Further, the tint block is formed by concentrating or distributing a plurality of the printing dots printed in the halftone dots without changing the position and gradation of each halftone dot group of the floating dot pattern, has information bits embed viewed possible information matrix "1" or "0" in each halftone dot, no void area dots printed around the information matrix is provided, the information on the outside of said void region Information description state information and position reference information are arranged so as to surround the matrix, and the information matrix, the gap region, the description state information, and the position information are configured by a repeating pattern as a unit,
Functional information for executing at least one desired function among a copy prohibition function, a tracking function, an automatic transmission function, a secret information concealing function, and an automatic reading function is embedded in each information matrix of the copy-forgery-inhibited pattern. Whether information for specifying the position of the function information embedded in the information matrix is embedded as the position reference information, and the function information is embedded in each halftone dot of the information matrix as the information description state information . is embedded information indicating whether,
A multi-information print medium, wherein a copy-forgery-inhibited pattern in which the various data is embedded and the desired print image are superimposed and printed. In the copy-forgery-inhibited pattern, the information bit is not embedded in the overlapping area where a part of the information matrix of the raised character pattern overlaps the data of the print image, and the information bit is not embedded in the overlapping area. Is embedded as the description state information, the information bit is embedded in an area other than the overlapping area of the information matrix, and the information bit is embedded in an area other than the overlapping area. The multi-information print medium according to claim 7, wherein information to be indicated is embedded as the description state information . Further, wherein the background pattern, the pattern in the multi-information printing medium according to claim 7 or 8, characterized in that the dot pattern is embedded which indicates that it is a copy prohibition or enable copying. An apparatus for reading multi-information recorded on the ground pattern from the multi-information print medium according to any one of claims 7 to 9,
An image input unit, a recognition unit, and a registration unit;
The image input unit reads a multi-information print medium as image data from an image sensor,
The recognizing unit reads the functional information from the information bits recorded in the halftone dots of the raised dot pattern of the image data;
The multi- information reading apparatus, wherein the registration unit stores the functional information read by the recognition unit in a memory or other recording medium. The recognizing unit further reads information on the copy prohibited or copyable dot pattern from the image data read from the multi-information print medium according to claim 9,
The multi-information reading apparatus according to claim 10, wherein the registration unit stores the copy prohibition or copy permission information in a memory or other recording medium in addition to the function information.