JPH1198345A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of the quality of an output image or the erroneous reading of identification information, and to simplify the reading work of identification information in a full color image forming device. SOLUTION: A tracing pattern signal generating part 3 prepares a monotone random pattern (s1), reads identification information such as an equipment number preliminarily written in a memory which is not shown in Figure (s2), prepares a stereoscopic graphic by segmenting the identification information from the random pattern according to a prescribed font and size (s3), and prepares a stereoscopic picture as a tracing pattern by continuously arranging the segmented stereoscopic graphics right and left in the original random pattern with an interval corresponding to popping amounts (s4). At the time of forming an image as the original picture, the tracing pattern of the stereoscopic image is outputted to a color image composing part 4 as image data in Y(yellow) with the lowest visibility (s5). Then, an output image is formed in a state that the stereoscopic image of the tracing pattern is added to the image data of the Y components of the original image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a function of preventing securities such as banknotes, stamps and stamps from being forged.

[0002]

2. Description of the Related Art In recent years, the image forming function of a full-color image forming apparatus has been remarkably improved, and it has become possible to forge securities such as banknotes, stamps and stamps using the full-color image forming apparatus. For this reason, it becomes necessary to provide the full-color image forming apparatus with a function of preventing forgery of securities.
There have been proposed full-color image forming apparatuses having various forgery prevention functions.

Among the forgery prevention functions provided in the conventional full-color image forming apparatus, the most common methods include a maker name and a machine number for identifying the full-color image forming apparatus at the time of image formation, a date for specifying the time of image formation, and the like. Is added to the original image as a tracking pattern in a low-visibility color such as yellow, for example, when identifying a forged security. A so-called tracking pattern method is known in which information is read and a full-color image forming apparatus used for creating the forged securities is specified.

[0004]

However, in the tracking pattern system, which is a conventional general forgery prevention system, dots representing identification information substantially uniformly over the entire surface of all original images formed in a full-color image forming apparatus. Since the tracking pattern of the pattern was added, even if the dot pattern was added in yellow with the lowest visibility, the tracking pattern partially changed in the output image due to the color of the original image where the dots of the tracking pattern overlapped. There is a case where the image can be clearly recognized, and the identification information may be read for that portion, which causes a problem of lowering the quality of the output image.

That is, in order to prevent the quality of the output image from deteriorating, it is necessary to prevent the identification information represented by the tracking pattern from being easily read. For this reason, there is a conventional tracking pattern method in which identification information is encrypted, and then the encrypted identification information is combined with the original image as a tracking pattern.

However, when the encrypted tracking pattern of the identification information is combined with the original image, the tracking pattern is extracted from the output image and further extracted in order to read the identification information in the formed output image. There is a problem that the tracking pattern needs to be decoded, and the work of reading the identification information becomes complicated and time-consuming.

Further, if the tracking pattern is partially contaminated in the output image, the entire tracking pattern cannot be accurately extracted and the identification information cannot be read.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tracking pattern type forgery prevention function which can reduce the quality of an output image due to the synthesis of a tracking pattern, prevent misreading of identification information, and facilitate the work of reading identification information. An object of the present invention is to provide an image forming apparatus having the same.

[0009]

According to the first aspect of the present invention, there is provided an image signal generating section for generating a specific image signal, and a specific image signal generated by the image signal generating section is combined with an image signal of an original image. An image signal synthesizing unit that performs image formation based on the image signal synthesized by the image signal synthesizing unit, wherein the image signal generating unit displays specific information in a stereoscopic image. Is a stereoscopic image signal generation unit that generates

According to the first aspect of the present invention, an image is formed in a state where a stereoscopic image signal for displaying specific information in a stereoscopic image and an image signal of an original image are combined. Therefore, when the formed image is viewed with a normal method, only the original image is visually recognized and specific information is not read, and the image quality of the original image is not significantly reduced. on the other hand,
By stereoscopically viewing the formed image, specific information can be read very easily.

According to a second aspect of the present invention, the stereoscopic image signal generates an autostereoscopic stereoscopic image signal for displaying a stereoscopic image visually recognized by autostereoscopic vision for a part of the specific information. And generating a non-autostereoscopic stereoscopic image signal for displaying a stereoscopic image visually recognized through the optical device for the portion.

In the invention described in claim 2, specific information represented by a stereoscopic image visually recognized by naked-eye stereoscopic vision and a stereoscopic image visually recognized through an optical device is combined with an original image. An image is formed. Therefore, only a part of specific information is read by autostereoscopically viewing the formed image, and another part of the specific information is read by stereoscopically viewing the formed image through the optical device. .

According to a third aspect of the present invention, there is provided an image signal generating section for generating a specific image signal, and an image signal synthesizing section for synthesizing the specific image signal generated by the image signal generating section with the image signal of the original image. Wherein the image signal generating unit converts an arrangement position of a specific image signal within a predetermined range in the image forming apparatus which forms an image based on the image signal synthesized by the image signal synthesizing unit. It is characterized by including a part.

According to the third aspect of the present invention, an image is formed in a state where a specific image signal whose arrangement position is converted within a predetermined range and an image signal of an original image are combined. Therefore, when the formed image is viewed as it is, only the original image is visually recognized and the content indicated by the specific image signal is not read, so that the image quality of the original image does not significantly deteriorate. On the other hand, by restoring the arrangement position of the formed image, the content indicated by the specific image signal can be read very easily.

According to a fourth aspect of the present invention, the image signal generator includes an error correction code generator for generating an error correction code for a part or all of a specific image signal. And generating a specific image signal to which the error correction code is added.

According to the fourth aspect of the present invention, an original image is formed in a state where a specific image signal to which an error correction code is added is synthesized. Therefore, even when a part of the specific image signal is contaminated in the formed image, the specific image signal is reproduced by performing the predetermined error correction processing, and the content indicated by the specific image signal is accurately read. You.

[0017]

FIG. 1 is a block diagram showing a configuration of a full-color image forming apparatus according to an embodiment of the present invention. In a full-color image forming apparatus 10 according to an embodiment of the present invention, an image signal of each of three colors of RGB, which are three primary colors of additive color mixing, is converted into three primary colors of subtractive color mixing in an image processing unit 6 from an image of a color original by a scanner unit 1. YM
The image data is converted into image data of each color of C and black K, and YMC
By sequentially supplying the image data of the four colors K to the laser control unit 5, the image forming process is continuously performed four times to form a full-color image.

The image processing unit 6 includes a color image processing unit 2, a tracking pattern signal generating unit 3, and a color image synthesizing unit 4.
It has. The color image processing unit 2 converts image signals of each color of RGB read by the scanner unit 1 into image data of each color of YMCK. Tracking pattern generator 3
The image data of the tracking pattern representing the identification information such as the machine number for specifying the full-color image forming apparatus
Create with any color of K. The color image synthesizing unit 4 converts the image data of the tracking pattern into the color image processing unit 2.
The image data is combined with any of the image data of YMCK input from the CPU and supplied to the laser control unit 5.

FIG. 2 is a flow chart showing a processing procedure of the tracking pattern signal generator constituting the full-color image forming apparatus according to the first and second embodiments of the present invention. The tracking pattern signal generating unit 3 creates an image signal of a three-dimensional image in which identification information can be visually recognized three-dimensionally by autostereoscopy using a known autostereogram technique. That is, the tracking pattern signal generator 3 first creates a monotone random pattern (s1). In this random pattern, the inside of a rectangle is divided into a number of small areas, and each of the small areas is painted irregularly in black and white.

Next, the tracking pattern signal generating section 3 reads out identification information such as a machine number previously written in a memory (not shown) (s2), and cuts out this identification information from a random pattern according to a predetermined font and size. A three-dimensional figure is created (s3), and image data of a three-dimensional image, which is a tracking pattern, is created by continuously arranging the cut-out three-dimensional figure in the original random pattern at intervals according to the amount of projection (s4). ).

Thereafter, the tracking pattern signal generating section 3 outputs image data of the tracking pattern to the color image synthesizing section 4 as, for example, Y (yellow) image data having the lowest visibility when forming an image of the original image. (S5).

The above processes s1 to s4 are executed at least once in the full-color image forming apparatus 10 according to the contents of the identification information. For example, when the identification information is a manufacturer name or a machine number that specifies the full-color image forming apparatus 10, these are information fixed for each full-color image forming apparatus 10 and are not changed later.
The processing of s1 to s4 is performed by 1 for each full-color image forming apparatus 10.
The image data of the three-dimensional image is stored in a memory, and the image data of the three-dimensional image is read out from the memory at the time of forming the image of the original image.
Can be output to

On the other hand, if the identification information is the date and time specifying the time of image formation, since the information is updated every time an image is formed, the processing of s1 to s5 is executed every time the image of the original image is formed. There is a need to.

By the above processing, in the full-color image forming apparatus 10 according to this embodiment, a full-color output image is formed in a state where the tracking pattern of the yellow stereoscopic image representing the identification information is combined with the original image. Therefore, the content of the identification information is the color with the lowest visibility, and exists in the output image as a stereoscopic image, and the identification information is extremely difficult to be visually recognized in a state where the original image is viewed in the output image. The image quality of the output image of the original image other than the securities does not deteriorate. In addition, by autostereoscopically viewing the output image, the tracking pattern representing the identification information can be visually recognized in a three-dimensional manner, and the identification information can be easily read. The device 10 can be easily specified by the tracking pattern method.

Since the tracking pattern of the three-dimensional image to be synthesized with the original image in the output image is created according to a certain creation procedure as described above, the output image of the full-color image forming apparatus 10 is read by an optical device. By extracting a random pattern by color separation of the read image and detecting a figure repeatedly arranged in the extracted random pattern, the identification information given to the output image can be read using a predetermined device. it can.

In the above-described example, the tracking pattern signal generating unit 3 creates a stereoscopic image as autonomous stereoscopically visible stereoscopic images that does not require optical equipment, as an autostereogram technique, as a tracking pattern. A stereoscopic image visually recognizable by non-stereoscopic stereoscopic vision using an optical device may be created as a tracking pattern by an anaglyph technique or the like.

Further, the tracking pattern signal generating section 3 creates a plurality of types of tracking patterns based on both a stereoscopic image visually recognizable by autostereoscopic viewing and a stereoscopic image recognizable by non-autostereoscopic viewing using optical equipment. It may be.
In this case, one of a stereoscopic image visually recognizable by autostereoscopic vision and a stereoscopic image recognizable by non-autostereoscopic vision may be selected according to the importance of the identification information represented by the tracking pattern.

FIG. 3 is a flow chart showing the processing procedure of the tracking pattern signal generator of the full-color image forming apparatus according to the embodiment of the present invention. The tracking pattern signal generation unit 3 adds an error correction code by a known error correction method to the image data of the tracking pattern to be synthesized with the original image, and then performs data processing on the image data of the tracking pattern including the error correction code by a known shuffling method. Is converted, and the converted image data is output to the color image synthesizing unit 4 as image data of a specific color.

That is, the tracking pattern signal generating section 3 first reads out identification information such as a machine number previously written in a memory (not shown) (s11), and adds a synchronization signal to the identification information (s12). For example, an error correction code such as a Reed-Solomon product code is added to the identification information to which the synchronization signal has been added (s13), and the data position of the image data of the identification information including the error correction code is shuffled and tracked. Create pattern image data (s
14).

Thereafter, the tracking pattern signal generating section 3 outputs image data of the tracking pattern to the color image synthesizing section 4 as, for example, Y (yellow) image data having the lowest visibility when forming an image of the original image. (S15).

In the processing of s11 to s14, if the pre-stored identification information is, for example, "F" as shown in FIG. A 2-bit synchronization signal indicating the start position of the data is added to the upper side, and a 3-bit error correction code is added to the right and lower sides of the image range in each of the row direction and the column direction of the identification information including the synchronization signal. (See FIG. 4B). The error correction code is calculated by applying data included in each data row of the identification information including the synchronization signal in the row direction and the column direction to a predetermined calculation formula.

Further, as for the image data of the error correction code and the identification information, for example, as shown in FIG.
5 is represented by (i ', j') = (i + j-1, 2 (i-1) + j) where 1≤i, i ′, J, j ′ ≦ 5... The coordinates (i ′, j ′) after the conversion obtained by the first equation are as shown in FIG.
A shuffle process for rearrangement is performed as shown in FIG. However,
In the first equation, i ′ and j ′ are mod 5 (constituted from 1 to 5). As a result, the error correction code and the image data of the identification information are rearranged as shown in FIG.

The processing in s11 to s14 is performed in s
Similarly to the processing of 1 to s4, the identification information that is executed at least once in the full-color image forming apparatus 10 according to the contents of the identification information, is executed only once for the identification information whose contents are not updated, and the identification information whose contents are updated Is executed each time the content of the identification information is updated or each time the image of the original image is formed.

The process of adding a synchronization signal in s12 and the process of adding an error correction code in s13 are as follows.
It is not essential, and either or both processes can be omitted. Through the above processing, the full-color image forming apparatus 10 according to the present embodiment outputs a full-color image in a state where the yellow tracking pattern representing the identification information is combined with the original image. Therefore, the content of the identification information is present in the output image with the least visible color and with the data position shuffled, and the identification information is legible when the original image is viewed in the output image. Is not performed, and the image quality of the output image of the original image other than the securities is not reduced.

FIG. 6 is a flowchart showing a processing procedure for reading identification information from an output image of the full-color image forming apparatus according to the embodiment of the present invention. When the identification information is read from the output image formed by combining the tracking pattern created by the processing shown in FIG. 3 with the original image, first, image data for each of RGB colors is converted from the output image via an optical device. Reading (s21), the read image data is converted into YMCK image data (s22), and the data area of the tracking pattern is extracted from the image data of the image color of the composite image among the converted image data (s23). At this time, when a synchronization signal is added to the image data of the tracking pattern, the data area of the tracking pattern can be extracted using the synchronization signal as a clue.

Next, data excluding the synchronization signal among the data included in the data area of the extracted tracking pattern is deshuffled (s24). This deshuffling process is a process of converting the data arrangement position in the opposite direction to the shuffling process in s14. When the shuffling process is performed according to the first equation, (i, j) = (i'- j ′ + 1,2i′−j ′) The coordinates (i, j) after the deshuffle are obtained by the second equation. However, in the second equation, i and j are mod5.

The identification information is read from the deshuffled data (s25). If the identification information cannot be read, an error correction process is performed using an error correction code (s2).
6, s27). That is, the identification information is reproduced based on the error correction code added to the identification information and the calculation formula used for calculating the error correction code.

According to the above processing, since the tracking pattern representing the identification information to be read has been shuffled in advance, when adding the error correction code to the identification information, the order of the calculation formula for calculating the error correction code is reduced. can do.
For example, in the matrix data shown in FIG. 5B, when D3 and D7 cannot be read due to contamination,
Two unknown data exist in the same row of the matrix, and secondary error correction is required in a state where the data shown in FIG. 5B is not shuffled. However, in the state where the data shown in FIG. 5 (B) is being shuffled, the data position is restored to the state shown in FIG. 5 (A) by the deshuffle processing, so that the dirty data is dispersed and D3 and D7 become The data can be moved to different rows and columns, and the data can be restored by primary error correction.

Therefore, the image data of the tracking pattern is shuffled and then combined with the image data of the original image to form an image, thereby facilitating the process of providing an error correction code and the error correction process. ,
The possibility of correction by low-order error correction, that is, the possibility of avoiding an uncorrectable state can be improved,
The probability that the full-color image forming apparatus used for counterfeiting securities can be specified by the tracking pattern method can be improved.

By setting the size of the image data of the tracking pattern to be at least one in the width direction of the image data of the securities, the identification information can be reliably read from the formed output image. Further, the probability that the full-color image forming apparatus used for counterfeiting securities can be specified by the tracking pattern method can be further improved.

Further, it is also possible to create image data for displaying the tracking pattern after the shuffle processing in a three-dimensional figure and to synthesize the image data with the image data of the original image. In this case, although the process for reading the identification information in the output image is complicated, the visibility of the identification information in the output image can be significantly reduced, and the image quality of the output image with respect to the original image can be maintained extremely high. can do.

Further, when the image data of the tracking pattern is added to any of the YMCK image data of the original image, the ratio of the image data of the tracking pattern to the image data of the original image is determined by the gradation reproduction of the full-color image forming apparatus. It can be determined in consideration of gender.

In addition, one piece of identification information can be divided and added to a plurality of pieces of image data of YMCK image data, and each piece of the plurality of pieces of identification information can be added to image data of a different color. .

[0044]

According to the first aspect of the present invention, an image is formed by synthesizing a stereoscopic image signal for displaying specific information in a stereoscopic image and an image signal of an original image. When the image is viewed by a normal method, only the original image is visually recognized and specific information is not read, and the image quality of the original image is not significantly reduced, and the formed image is stereoscopically viewed. Thereby, specific information can be read very easily.

According to the second aspect of the present invention, the specific information represented by the stereoscopic image visually recognized by the naked-eye stereoscopic vision and the stereoscopic image visually recognized through the optical device is combined with the original image. By forming an image, it is possible to read only a part of specific information by stereoscopically viewing the formed image, and to perform specific information by stereoscopically viewing the formed image through an optical device. Can be read, and the visibility of specific information can be differentiated by a plurality of modes according to the content.

According to the third aspect of the present invention, an image is formed in a state in which a specific image signal whose arrangement position in a predetermined range has been converted and an image signal of an original image are formed. When the image is viewed as it is, only the original image is visually recognized, the content indicated by the specific image signal is not read, the image quality of the original image is not significantly reduced, and the arrangement position of the formed image is changed. By restoring, the content indicated by the specific image signal can be read very easily.

According to the fourth aspect of the present invention, by forming an original image in a state where a specific image signal to which an error correction code is added is synthesized, a part of the specific image signal in the formed image is formed. Can be reproduced by a predetermined error correction process even if the image is stained, and the contents indicated by the specific image signal can be accurately read.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a full-color image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of a tracking pattern signal generation unit included in the full-color image forming apparatus according to the first and second embodiments of the present invention.

FIG. 3 is a flowchart illustrating a processing procedure of a tracking pattern signal generation unit of the full-color image forming apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing a creation state of image data of identification information in the full-color image forming apparatus.

FIG. 5 is a diagram illustrating an example of a shuffle process in the full-color image forming apparatus.

FIG. 6 is a flowchart illustrating a processing procedure when reading identification information from an output image of the full-color image forming apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1-scanner 2-color image processing unit 3-tracking pattern signal generating unit 4-color image synthesizing unit 5-laser control unit 6-image processing unit 10-full color image forming apparatus

Claims (4)

[Claims] An image signal generating section for generating a specific image signal; and an image signal synthesizing section for synthesizing the specific image signal generated by the image signal generating section with an image signal of an original image. An image forming apparatus that forms an image based on an image signal synthesized by a unit, wherein the image signal generating unit is a stereoscopic image signal generating unit that generates a stereoscopic image signal for displaying specific information in a stereoscopic image. Image forming apparatus. 2. The stereoscopic image signal generates an autostereoscopic stereoscopic image signal for displaying a stereoscopic image visually recognized by autostereoscopic vision for a part of specific information, and the other part of the specific information via an optical device. The image forming apparatus according to claim 1, wherein the image forming apparatus generates a non-stereoscopic three-dimensional image signal for displaying a three-dimensional image visually recognized. 3. An image signal synthesizing section, comprising: an image signal generating section for generating a specific image signal; and an image signal synthesizing section for synthesizing the specific image signal generated by the image signal generating section with an image signal of an original image. An image forming apparatus that forms an image based on an image signal synthesized by a unit, wherein the image signal generating unit includes an image signal converting unit that converts an arrangement position of a specific image signal within a predetermined range. Image forming apparatus. 4. An image signal generating section comprising an error correcting code generating section for generating an error correcting code for a part or all of a specific image signal, wherein an error correcting code generated by the error correcting code generating section is added. 4. A specific image signal is generated.
An image forming apparatus according to claim 1.