JP4527294B2 - How to create a forgery prevention pattern - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of creating counterfeit prevention pattern, in particular of preventing duplicated by the color copier of the digital system, or forgery by treating the images captured by the digital scanner, a digital camera, or the like on a computer directed to create a forgery prevention pattern.
[0002]
[Prior art]
Securities such as various checks, gift certificates, lottery tickets and tickets are distributed and used. Needless to say, these securities have high economic value, so there is a strong demand for prevention of counterfeiting (counterfeiting). From the viewpoint of prevention of counterfeiting (counterfeiting), for example, precise ground patterns are provided. Forgery has become more sophisticated with the development of color copying machines, and the general public has become easy to obtain the copying machines due to high performance (digitalization) and low prices of color copying machines. The securities can be easily counterfeited simply by copying the securities with a copier, and the securities can be read with a color scanner and color on the personal computer due to high performance and low price of personal computers, color printers and color scanners. By correcting and outputting the color corrected content with a color printer, it is now possible to manufacture imitations that are closer to the actual product.
For this reason, there is a demand for a method for creating an anti-counterfeit pattern and an anti-counterfeit printed matter that have been subjected to a more appropriate anti-counterfeiting process.
[0003]
As a conventional anti-counterfeiting pattern, there is a method of designing and using a design in which geometric patterns are diversified. As a method of using a design obtained by diversifying the geometric pattern in the design, there are a ground pattern, a colored pattern, a relief pattern, etc. as a design of printed matter such as securities. In these, a pattern is basically constituted by a set of curved lines having a fixed line width. These patterns can be complicated by taking into account the design of the printed matter, or by using colors that are difficult to reproduce by a scanner or copying machine, or by forming them with complicated curved lines, Since the prevention of counterfeiting can be suppressed by generating moire for scanning input / output, it is widely adopted.
[0004]
For example, in the “collective pattern for continuous tone expression” of Japanese Patent Application Laid-Open No. 2000-218922, points and lines, and parallel or parallel to each other while intersecting the lines at an arbitrary angle according to the continuous tone. A method is disclosed in which the density of an image is expressed in gradation using a line drawing formed body with arranged line segments.
[0005]
[Problems to be solved by the invention]
However, when the object is expressed by a line drawing based on a combination of points, lines, and line segments as in the conventional example, each point, line, and line segment can be handled as a single unit, so that the forger recognizes each shape. There is a problem that it is easy to reproduce them by extracting them individually and combining them, and it is difficult to create a complicated line drawing.
[0006]
The present invention has been made in view of the above problems, and has a complicated anti-counterfeiting pattern for preventing forgery by copying on a computer or processing an image captured by a digital scanner or digital camera on a computer. The purpose is to provide a creation method.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is arbitrarily set with an acquisition step of acquiring image data for creating a forgery prevention pattern, and a division step of dividing the acquired image data into blocks A creation step for creating gradation patterns (gradation reproduction patterns) for the number of gradations, an evaluation step for evaluating density information of each block of the divided image data based on the number of gradations, and the image A replacement step of replacing each block of data with a gradation pattern (tone reproduction pattern) corresponding to the number of gradations arbitrarily set corresponding to the evaluation, and the gradation pattern replaced by the replacement step ( possess a plate step of performing a printing plate using the image represented by tone reproduction pattern), the said in a substitution step, the gradation pattern (tone reproduction gradation number of which is set to the arbitrary pattern) The end is set at a position where adjacent gradation patterns are connected to each other, and the gradation pattern (gradation reproduction pattern) is one of a rectangular wave shape, a sine wave shape, a sawtooth shape, a combination thereof, or It is characterized by comprising a combination of waveform shapes of the same type. This makes it possible to efficiently create a complicated forgery prevention pattern. This makes it possible to create a forgery prevention pattern that is difficult to forge even using a personal computer.
[0010]
According to the second aspect of the present invention, the end portions of the gradation patterns (gradation reproduction patterns) corresponding to the number of gradations set arbitrarily are half of the width direction of the gradation patterns (gradation reproduction patterns). A semicircular round having a length as a radius is formed. This makes it possible to create an anti-counterfeit pattern that has no jagged feeling in an image composed of gradation patterns that are connected to each other and that is excellent in aesthetics.
[0016]
<Action>
The present invention divides image data for creating an anti-counterfeit pattern into blocks of the same shape of arbitrary size, and replaces them with gradation patterns (gradation reproduction patterns) corresponding to the image density of the individual blocks. An anti-counterfeit pattern expressed in gradation by an aggregate of gradation patterns (tone reproduction patterns) to be created is created.
[0017]
Further, the present invention makes it possible to create a forgery prevention pattern with a higher anti-counterfeit effect that is more excellent in design by connecting the ends of adjacent gradation patterns (tone reproduction patterns). .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for creating a forgery prevention pattern and a forgery prevention printed matter according to embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 to FIG. 8 show an example of an embodiment of a method for creating a forgery prevention pattern and a forgery prevention printed matter according to the present invention.
[0019]
FIG. 1 is a flowchart showing a method for creating a forgery prevention pattern according to an embodiment of the present invention. A method for creating a forgery prevention pattern and a forgery prevention printed matter will be described below with reference to the flowchart of FIG.
[0020]
First, image data is captured as digital data by a digital scanner, a digital camera, or the like (step S1).
[0021]
Next, the image data captured in step S1 is divided into rectangular blocks having an arbitrary size, for example, of the same shape (step S2). The shape of the blocks divided here is not particularly limited, and may be circular or polygonal (such as rhombus or hexagon), or may be a combination of blocks of different sizes. By setting the size small, the resolution of the forgery prevention pattern to be formed can be improved.
[0022]
Next, it is determined in which gradation the captured image data is to be expressed, and arbitrary gradation patterns corresponding to the determined gradation number are created (step S3). For example, at this time, when expressing with two gradations, two different gradation patterns are created, and when expressing with ten gradations, ten different desired gradation patterns are created.
[0023]
Next, the density information for each block of the divided image data is evaluated based on the set number of gradations (step S4). Here, it is evaluated to which gradation number arbitrarily set the density information of each block of the image data corresponds.
[0024]
Next, based on the result evaluated in step S4, replacement with a previously created gradation pattern is performed (step S5). For example, at this time, if it is intended to express with two gradations, if the density information in an arbitrary block is 0 to less than 50%, the gradation pattern created as the first gradation is replaced with 50 to 50%. If it is 100%, a process of replacing with the gradation pattern created as the second gradation is performed.
[0025]
When the replacement processing for the gradation pattern in each block of image data is completed, the end of the gradation pattern of the adjacent block is connected, and this is output as a film original, and a printing plate is created based on this film original. The printing plate is prepared and processed (step S6).
[0026]
An anti-counterfeit printed matter is printed using the printing plate created by this printing plate process (step S7). Further, it is also possible to form a printing plate by directly outputting a gradation pattern using CTP instead of outputting the film original plate.
[0027]
Here, the term “join” refers to the end of the gradation pattern replaced with an arbitrary block and the end of the gradation pattern replaced with a block adjacent to the arbitrary gradation pattern (horizontal, vertical, diagonal). By designing the gradation pattern in advance so that and are at the same position, the forgery prevention pattern can be formed as a continuous line drawing.
[0028]
As described above, according to the method for creating a forgery prevention pattern of the present invention, it is possible to easily create a line drawing composed of a plurality of complicated continuous lines.
[0029]
In addition, the forgery-preventing printed matter of the present invention is reproduced by a plurality of continuous lines because the gradation pattern is replaced based on the density information of the original image data and the ends of the adjacent gradation patterns are connected. It becomes a line drawing. When such anti-counterfeit printed matter is copied with a copying machine, it is not accurately reproduced or reproduced with moiré in the area where line drawings are crowded. be able to. The same applies to the case where the forgery prevention printed matter of the present invention is read by the scanner.
[0030]
In addition, when the anti-counterfeit pattern created as described above is printed with special ink that is difficult to reproduce at the time of copying, the pattern is not accurately reproduced on the copied material, so that it can be easily identified as a copied material.
[0031]
FIG. 2 is the original image data for creating the anti-counterfeit pattern of the present invention, and FIG. 3 is a plan view showing a specific example of the image data dividing process for creating the anti-counterfeit pattern. In FIG. 3A, image data is divided into square blocks, and consistency between blocks arranged in the vertical direction and the horizontal direction is obtained. Further, in FIG. 3B, the image data is divided under the above-described conditions, the consistency is obtained only in the horizontal direction, and the vertical direction is divided by an arbitrary width. Further, it is possible to achieve alignment only in the vertical direction and to divide the image by shifting an arbitrary width in the horizontal direction.
[0032]
FIG. 4 is a diagram for explaining the connection between the edge portions of the gradation patterns for the number of gradations arbitrarily set and the gradation patterns adjacent to each other.
Usually, as shown in FIG. 4A, the end portion of the replaced gradation pattern has an angular end portion in any gradation pattern having different amplitudes. When connected in such a state, as shown in FIG. 4 (b), a gap is generated at the connection portion of the gradation patterns, so that the appearance of the finished printed matter is impaired and the aesthetic appearance is deteriorated. was there.
[0033]
As a method for solving such a problem, in the present invention, as shown in FIG. 4C, any gradation pattern having a different amplitude is created so that the end thereof is rounded. This roundness is a semicircular roundness having a radius of ½ length in the width direction of the gradation pattern at the end.
[0034]
As described above, when the edge of the gradation pattern is rounded, as shown in FIG. 4D, the connection portion between the ends of the gradation pattern is smoothly connected based on the circle, and a gap portion is generated. Since it is recognized as a single continuous line, it is possible to provide an anti-counterfeit printed matter having an excellent design and good appearance.
[0035]
Hereinafter, an embodiment in which image data for creating an anti-counterfeit pattern is divided into 0.5 mm × 0.5 mm matrix blocks and the line width of each gradation pattern is formed to be 0.08 mm will be described in detail below. .
[0036]
<First embodiment>
FIG. 5 is a plan view showing an anti-counterfeit printed matter according to the first embodiment of the present invention.
In FIG. 5, the anti-counterfeit printed matter according to the first embodiment of the present invention has 11 different amplitudes shown on the left side of FIG. 4 in order to represent the captured image data as an anti-counterfeit pattern of 11 gradations. A gradation pattern composed of rectangular waves is created, density information of each divided block is evaluated in 11 stages, and a replacement process with a gradation pattern is performed based on the result.
[0037]
Referring to the gradation pattern 1 based on a rectangular wave, the gradation pattern is replaced with a rectangular wave gradation pattern in which the amplitude is large in the portion where the density of the original image data is high and the amplitude is small in the thin portion. In addition, the ends of adjacent gradation patterns are connected in the horizontal direction.
[0038]
<Second embodiment>
FIG. 6 is a plan view showing an anti-counterfeit printed matter according to the second embodiment of the present invention.
In FIG. 6, the anti-counterfeit printed matter according to the second embodiment of the present invention has 11 different amplitudes shown on the left side of FIG. 6 in order to represent the captured image data as an anti-counterfeit pattern of 11 gradations. A gradation pattern composed of a sine wave is created, density information of each divided block is evaluated in 11 stages, and a replacement process with a gradation pattern is performed based on the result.
[0039]
Referring to the gradation pattern 2 using a sine wave, the original image data is replaced with a sine wave gradation pattern having a large amplitude at a high density portion and a small amplitude at a thin portion. In addition, the ends of adjacent gradation patterns are connected in the horizontal direction.
[0040]
<Third embodiment>
FIG. 7 is a plan view showing an anti-counterfeit printed matter according to the third embodiment of the present invention.
In FIG. 7, the anti-counterfeit printed matter according to the third embodiment of the present invention has 11 different amplitudes shown on the left side of FIG. 7 in order to represent the captured image data as an anti-counterfeit pattern of 11 gradations. A gradation pattern composed of a sawtooth wave is created, density information of each divided block is evaluated in 11 stages, and a replacement process with a gradation pattern is performed based on the result.
[0041]
Referring to the sawtooth gradation pattern 3, the original image data is replaced with a sawtooth gradation pattern in which the amplitude is large in the high density portion and the amplitude is small in the thin portion. The ends of adjacent gradation patterns are connected and printed in the horizontal direction.
[0042]
<Fourth embodiment>
FIG. 8 is a plan view showing an anti-counterfeit printed matter according to the fourth embodiment of the present invention.
In FIG. 8, the anti-counterfeit printed matter according to the fourth embodiment of the present invention expresses the captured image data as a 16-gradation anti-counterfeit pattern, and therefore, combinations of 16 different amplitudes shown on the left side of FIG. A gradation pattern is created by (in this embodiment, a combination of sine waves), the density information of each divided block is evaluated in 16 stages, and a replacement process with a gradation pattern is performed based on the result. It is a thing.
[0043]
Referring to the gradation pattern 4 based on a combination of sine waves, a gradation pattern having a high amplitude in a portion where the density of the original image data is high and a gradation pattern having a small amplitude in a thin portion is replaced. Further, the end portions of adjacent gradation patterns are connected and printed in the horizontal direction and the vertical direction. In order to connect the ends in the vertical direction, as shown in FIG. 3B, blocks arranged in the vertical direction are formed so that the ends overlap.
[0044]
The above-described embodiment shows a preferred embodiment of the present invention, and various modifications can be made without departing from the gist of the present invention. For example, in the embodiment of the present invention, the gradation pattern is formed by a rectangular wave, a sine wave, a sawtooth wave, or a combination thereof. However, the present invention is not limited to these, and at least when the patterns are connected to each other. In addition, the shape is not particularly limited as long as it can be recognized as a continuous line.
[0045]
【The invention's effect】
As can be seen from the above description, according to the method for creating a forgery prevention pattern of the present invention, when image data is divided into blocks, based on the density information of each block of the image data, a desired prepared It is created by substituting different gradation patterns for the number of gradations and connecting these gradation patterns. Therefore, in the conventional anti-counterfeiting measures using a copy-forgery-inhibited pattern, a relief pattern, etc., there is a possibility that it is reproduced by repeating only a specific pattern, but in the present invention, a gradation pattern of an arbitrary shape is combined. As a result, gradation expression consisting of continuous lines is possible, so that it is possible to provide a method for creating a forgery prevention pattern that is excellent in design, has a good appearance, is complex, and is difficult to forge.
[0046]
Further, according to the forgery-preventing printed matter of the present invention, continuous gradation is expressed as a line drawing by connecting adjacent gradation patterns, so that moiré occurs when reproduced by a scanner or a copying machine. Therefore, it is possible to provide an anti-counterfeit printed matter that can be easily recognized visually by a visual inspection.
[0047]
Furthermore, according to the forgery-preventing printed matter of the present invention, it is possible to provide a forgery-preventing printed matter that is difficult to reproduce by a scanner or a copying machine, is excellent in design, has a good appearance, and is complex and difficult to forge.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a method for creating a forgery prevention pattern according to an embodiment of the present invention.
FIG. 2 is a plan view showing original image data for creating a forgery prevention pattern.
FIG. 3 is a plan view showing an example of image division processing;
FIG. 4 is an enlarged view showing a connection state of end portions of a gradation pattern.
FIG. 5 is a plan view of an anti-counterfeit printed matter according to the first embodiment of the present invention.
FIG. 6 is a plan view of a forgery-preventing printed material according to a second embodiment of the present invention.
FIG. 7 is a plan view of a forgery-preventing printed material according to a third embodiment of the present invention.
FIG. 8 is a plan view of a forgery-preventing printed material according to a fourth embodiment of the present invention.
[Explanation of symbols]
1 Gradation pattern by rectangular wave 2 Gradation pattern by sine wave 3 Gradation pattern by sawtooth wave 4 Gradation pattern by combination of sine waves

Claims (2)

An acquisition step of acquiring image data for creating a forgery prevention pattern;
A dividing step of dividing the acquired image data into blocks;
A creation process for creating gradation patterns (gradation reproduction patterns) for an arbitrarily set number of gradations;
An evaluation step of evaluating density information of each block of the divided image data based on the number of gradations;
A replacement step of replacing each block of the image data with gradation patterns (gradation reproduction patterns) for the number of gradations arbitrarily set corresponding to the evaluation;
A printing plate step for performing printing using the image represented by the gradation pattern (tone reproduction pattern) replaced by the replacement step, and
In the replacement step, end portions of the gradation patterns (gradation reproduction patterns) for the arbitrarily set number of gradations are set at positions where adjacent gradation patterns are connected,
The gradation pattern (gradation reproduction pattern) is one of a rectangular wave shape, a sine wave shape, a sawtooth wave shape, a combination thereof, or a combination of the same type of waveform shape. How to make.   The edge of the gradation pattern (gradation reproduction pattern) for the number of gradations set arbitrarily is a half whose radius is half the length of the gradation pattern (gradation reproduction pattern) in the width direction. 2. The method for creating a forgery prevention pattern according to claim 1, wherein a circular round shape is formed.

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