KR20040090007A - Anti-copying method and system for hard-copy documents - Google Patents

Abstract

PURPOSE: A method and a system for preventing hardcopy duplication are provided to distinguish a copy with the naked eye by appearing a hardcopy duplication preventing pattern invisible in an original hardcopy if the original hardcopy is copied by a color printer or is scanned by a scanner. CONSTITUTION: A storage(100) stores information for a plurality of output devices and a plurality of binary pattern map information matched with output device information. A controller(110) outputs the binary pattern map information in order to enable a user to select a binary pattern map, generates the hardcopy duplication preventing pattern by using the selected binary pattern map, and generates a hardcopy duplication preventing document by inserting the hardcopy duplication preventing pattern into the hardcopy document. An output tool(120) outputs the hardcopy document having the hardcopy duplication preventing pattern. An input tool(130) outputs a signal for selecting the hardcopy duplication preventing pattern to the controller depending on user's manipulation.

Description

Anti-copying method and system for hard-copy documents

The present invention relates to a hard copy copy protection method and system.

More specifically, when printing an original containing a copy protection pattern on a plain paper using a regular printer, copying the original hard copy with a color copier, or scanning and reprinting it with a scanner, the special hard copy cannot be seen in the original hard copy. The present invention relates to a hard copy copy protection method and system for visually distinguishing a copy by displaying a hard copy copy protection pattern made of text or an image.

In recent years, counterfeits such as banknotes, checks, gift certificates and ID cards using high-performance copiers and scanners are frequently generated. To prevent such counterfeiting, use special watermark paper or print intaglio, latent image, micro-printing, optical variable ink, OVD (optical) Variable Device, See-through, Special Ink, Hologram Printing, Bar Code Printing, Optical Mark Reader (OCR) / Magnetic Ink Character Reader (MICR) Numbering Printing, etc. Although it is used, the above-described techniques have a problem that it takes a lot of expensive costs.

In addition, there is a problem that it is impossible for ordinary users to use expensive special papers or printing techniques in the issuance of civil documents, administrative certificates, various ticket tickets, small gift certificates, etc. of the administrative institution through the Internet.

In addition, the electronic civil processing, which is a core service of the e-government civil service innovation, can apply for civil documents such as resident registration copies, family registers / herbs, building books, etc. directly from the home or office. In other words, after accessing the homepage, entering their information, selecting the application form, paying a fee through credit card, electronic money or online deposit, the applicant will deliver the document to the desired place.

However, the complainant cannot print the complainant's documents directly through his computer and printer, and even though the complainant prints the hard copy, it is for simple reading and has no legal effect or evidence. Because there is no technical solution to control network printer control or forgery, it is difficult to admit it as a legal administrative document.

Therefore, technologies related to hard copy copying have been developed. In particular, US Pat. No. 5,374,976, which can be referred to as a prior art, varies the angle of the minimal line so that the original looks like a uniform pattern but is not suitable for color copying or scanning. In the case of the reproduction document, it is a technique that can be recognized by the eye by the difference of angle between the minimum lines. It is similar to the intaglio latent image used in the 10,000 won bill. US Patent No. 6000728 discloses a method for changing the size of a dot screen, and International Patent Application No. PCT / SG00 / 00147 discloses a technique for preventing forgery / falsification of a document using a multilayer optical watermark.

These inventions have a problem that when scanned with a high-resolution scanner of more than 1200ppi (pixels per inch) it is difficult to distinguish the pattern of the original and the copy, and you can see the hidden phrase if you look closely at the original.

In addition, there have been many inventions for preventing document tampering by inserting fragile watermarks, which are easily damaged when attempting to forge / modify originals. And there was a problem that additionally needs hardware and software for judgment.

Accordingly, the present invention has been made in view of the above-described problems of the prior art, an object of the present invention is to output an original containing a copy protection pattern on a plain paper using a general printer, the original hard copy color copy machine Hard copy copy protection pattern created by special phrases or images that cannot be seen in the original hard copy, and then reprinted by scanning with a scanner. It is.

1 is a flowchart illustrating a hard copy copy protection method according to the present invention;

2 is an embodiment of a binary pattern map to be applied as a copy protection pattern in FIG. 1;

FIG. 3 is an embodiment of a dot gain and half toning test to be applied to a printer to output a copy protection pattern in FIG. 1;

4 illustrates an embodiment of a halftone cell and a spot to be applied to the copy protection pattern in FIG. 1;

5 is another embodiment of a halftone cell and a spot to be applied in pairs with FIG.

6 is an embodiment of a copy protection pattern generated using halftone cells and spots,

FIG. 7 is a view for explaining a result of outputting after scanning an original hard copy including the copy protection pattern of FIG. 6 using a high resolution scanner; FIG.

8 is another embodiment of a halftone cell and a spot to be applied as a copy protection pattern in FIG.

9 is another embodiment of a halftone cell and a spot to be applied in pairs with FIG.

10 is a block diagram illustrating a hard copy copy protection system according to the present invention.

*** Explanation of main parts of drawing ***

100: storage unit 110: control unit

120: output unit 130: input unit

According to an embodiment of the present invention for achieving the above object, in the method for generating a copy protection pattern of a hard copy document, (1) a process of generating and storing a binary pattern map that is a copy protection pattern for each output device; ; (2) generating a half tone cell and a spot using the binary pattern map selected by the user; And (3) generating a hard copy copy protection pattern by using the generated half tone cells and spots and combining the generated document with a document to be output; A hard copy copy protection method comprising: solving the above problems.

At this time, the copy protection pattern is a hard copy copy protection method, characterized in that the character or company logo stored in the form of a bitmap or picture file, solves the above problems.

The hard copy copy protection pattern may include a half tone cell having a predetermined size and a half tone dot (or cell) inserted into the half tone cell. Solve one task.

Here, the said half tone cell and the half tone dot are a hard copy copying prevention method characterized by combining dots of different colors by a juxtaposition subtraction mixing system, and solves the above-mentioned subject.

In addition, the half tone cell and the half tone dot is a hard copy copy protection method, characterized in that the combination of the dots of different colors are formed by the color complementary color scheme, solving the above problems.

According to another embodiment of the present invention, storage means for storing information on a plurality of output devices and a plurality of binary pattern map information matched to the output device information; Output the binary pattern map information of the storage means on the screen for the user to select, create a hard copy copy protection pattern by using the binary pattern map information selected by the user, and hard to the user-created document Control means for inserting a copy copy protection pattern to generate a hard copy copy protection document; Output means for outputting a hard copy document having the hard copy copy protection pattern in response to the control of the control means; And input means for outputting a hard copy copy protection pattern selection signal according to a user's operation; As a hard copy copy protection system, characterized in that it comprises a, solving the above problems.

The control means may generate a half tone cell and a spot using the binary pattern map selected by the user, and generate a hard copy copy protection pattern using the generated half tone cell and the spot. The hard copy copy protection system solves the above problem.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

According to an embodiment of the present invention, as shown in FIG. 10, the storage unit 100 stores information on a plurality of output devices and a plurality of binary pattern map information matched to the output device information. Output the binary pattern map information of the storage unit 100 to be selected on the screen, create a hard copy copy protection pattern by using the binary pattern map information selected by the user, hard copy generated by the user A control unit 110 for inserting a hard copy copy protection pattern into a document to generate a hard copy copy protection document, and an output unit for outputting a hard copy document having the hard copy copy protection pattern under the control of the control unit 110. And an input unit 130 for outputting a hard copy copy protection pattern selection signal to the controller 110 according to a user's manipulation.

In this case, the controller 110 generates a half tone cell and a spot using the binary pattern map selected by the user, and generates a hard copy copy protection pattern using the generated half tone cell and the spot.

In this case, the copy protection pattern includes a character or a company logo stored in the form of a bitmap or a picture file.

The hard copy copy protection pattern may be formed by inserting a half tone cell having a predetermined size and a half tone dot (or cell) into the half tone cell, and the half tone cell and the half tone dot Dots of different colors are formed by the juxtaposition subtraction mixing method, or dots of different colors are formed by the color complementary color method.

Referring to the operation of the hard copy copy protection system configured as described above are as follows.

First, by generating and supplying a binary pattern map, which is a copy protection pattern, for each output device, users who want to use the copy protection pattern can create a hard copy copy protection document by selecting a binary pattern map suitable for their output device. . That is, a supplier (hereinafter referred to as a 'supplier') that generates and supplies a copy protection pattern generates a binary pattern map for each output device (for example, a printer) to generate halftone cells and spots, Create a hard copy copy protection pattern using ton cells and spots, combine it with a hard copy document, output it to an output device, check it visually, and when the copy protection pattern is confirmed, save it on a recording medium such as a CD-ROM. Make it available to the users you want. Of course, it can be implemented to be downloaded through a data communication network such as the Internet.

As described above, the terminal PC storing the copy protection pattern supplied through the storage medium or the data communication network supports the user to select the binary pattern map to generate the copy protection pattern.

That is, the controller 110 of the terminal PC provides a menu item for generating a copy protection pattern in response to a user's request, and when the user selects a binary pattern map through the menu item, the controller 110 In response to the hard copy copy protection pattern selection signal of the input unit 120, the selected binary pattern map is read from the storage unit 100 to generate a half tone cell and a spot.

Then, the controller 110 generates a hard copy copy protection pattern by using the generated half tone cell and the spot, combines the document with the user's document, and outputs the same through the output unit 130.

When the document in which the hard copy copy protection pattern is inserted is copied with a color copier or scanned using a scanner as described above, a pattern called a copy is exposed as shown in FIG. 2 (an example of a binary pattern map). At this time, the pattern may be a copy, a copy, a fake, a forgery, a sample, a dog, a COPY (ORIGINAL), an INVALID (VALID), a UNAUTHORIZED (AUTHORIZED), a VOID (VALID), a DUPLICATE (ORIGINAL), or a logo such as a company mark. Can be configured. Of course, you can also use your favorite patterns in bitmaps or other image files.

Referring to the technique of the copy protection pattern at this point, first, Figure 3 is a representation of the vertical, horizontal line, block having a dot size from 1 to 19 and the gray level (Gray level) at each block size. In this case, the gradation is increased by 8 from 0 to 255. Since the method of dot gain and half toning is different for each printer, it is necessary to determine the optimum block size after outputting such a pattern to the corresponding printer.

4 and 5 are examples of binary data of FIG. 2, wherein each binary data of a pattern map is made of 10 × 10 halftone cells, and a half of 2 × 2 fixed size is contained in the cell. Place halftone dots or spots to produce a copy protection pattern.

In color printing, on the other hand, a digital halftoning method uses a limited number of colors (CMYK) to form a pattern of pixels to produce a continuously colored image. This process is also called digital halftoning or AM (Amplitude Modulation) screening, and it adjusts the dot pattern, the size of the dots, and the shape of the dots, causing optical illusions in the human eye. It is a technique which shows a figure as an approximation.

Since the half-toning characteristic as described above is different for each printer, different printers have different copy protection patterns.

In addition, the dot gain (dot gain spread) is that the dot area of the printing plate does not coincide with the ink area of the print when it is printed through the printer. Many differences occur depending on whether ink is used or ink is used.

That is, FIG. 3 is composed of four pictures, the upper left picture is a pattern taken from 1 to 19 dot sizes to test the dot size in the vertical direction, and the upper middle picture of FIG. 3 is the dot size in the horizontal direction. In order to test the pattern, the pattern is taken from 1 to 19 dots, and the figure on the upper right of FIG. 3 shows one side of the square from 1 (1 × 1) to 19 (19 × 19) to test the size of the dot having a square shape. ) It is a pattern taken in dot size. In the lower figure of FIG. 3, the gradation diagram is continuously changed in the figure of the upper right of FIG. 3.

In addition, the gray level of the digital image has a value of 0 to 255, and since half of the toning is not possible because of limited ink, the half-toning characteristic of the printer can be visually detected by the pattern.

That is, when the above pattern is output to the printer, the printing characteristic of the printer-the size of the dot can be roughly grasped.

After all, it is easy to determine the halftone cells and spots after visually checking the characteristics of the printer. Therefore, a copy protection pattern is generated only after a step of outputting these patterns and visually checking them.

And, as shown in the accompanying drawings, Figures 4 and 5 is an example of binary data of FIG. That is, each binary data of the pattern map is made into 10 x 10 halftone cells. A halftone dot or spot of 2x2 fixed size is placed in this one cell. In this case, when the color is mixed, it becomes a different color. The method of mixing the colors by painting colors is called mixing or subtracting mixing of the colorants. In the subtraction mix, cyan (C: Cyan), magenta (M: Magenta, purple), and yellow (Y: Yellow) are the three primary colors (CMY). Mixing CMY at different intensities can produce different colors. In the case of subtractive mixing, when two colors in complementary colors are mixed, they become gray or black (both achromatic). There may be a combination of red and cyan, yellow and indigo, green and orange.

On the other hand, in halftone patterning, each of the four CMYK plates is printed at different angles to form rosettes of dots, as shown in the accompanying drawings, FIGS. 4 and 5. In color printing, four color halftones are combined to express density or color tone. Traditionally, C plate is 105 degrees, M plate is 75 degrees, Y plate is 0 or 90 degrees, and K (black, blacK) plate is Print at 45 degrees. If you print the maximum CMY, you should see black, which is actually K or brown because it is printed in dark green.

On the other hand, when the binary data of FIG. 2 is 1, the halftone dots are arranged in 'CMYK' order as shown in FIG. 4, and in the case of 0, the halftone dots are arranged in 'KYMC' order as shown in FIG. 5. The two binary data have a slight difference in size and shape. In all cases, the CMYK value is adjusted so that the document can be displayed in black and white, gradation, or even color images with juxtaposition blending characteristics at about 30cm away from the document. In other words, since our eyes are experimentally known to have a resolution of 250 dpi when viewed at a distance of 30 cm, we cannot distinguish two halftone cells at a distance of about 30 cm.

In the case of FIG. 4, K (black dot) is located at the bottom right at 2 × 2 pixels, and in FIG. 5, K is located at the top left at 2 × 2 pixels, and one pixel is too small at 2 × 2 pixels. The center of gravity of the pixel changes slightly depending on the position of K. In FIG. 4, the center point of 2 × 2 pixels is shifted from the center of the pixels to the lower right. In FIG. 5, the center point of 2 × 2 pixels is shifted from the center of the pixels to the upper left.

Drawing the relationship between the center and the surrounding CMY pixels as described above gives directionality, and if you actually print and observe in detail with a magnifying glass, you can feel this directionality.

Accompanying drawings Figure 6 is a hard copy of the original implemented as described above, it is not possible to recognize the hidden phrase because it appears as a uniform black and white or grayscale image. That is, even if the colors can be distinguished by different combinations of CMYKs, the hidden phrases cannot be recognized.

However, when copying with a color copier or scanning with a scanner and outputting it again, the dot gain between CMYK inks is not constant and the color balance is broken. That is, it is easy to recognize that the individual dots have different colors and thus the difference between the background and the hidden phrase.

And CMY alone cannot make a perfect black, but if one dot is designated as K, four dots appear as one black dot overall. However, depending on the location of the black has a direction that can not be recognized by the eye. In the case of juxtaposition blending, the brightness and saturation are perceived as the average value of the sum of the two colors divided by the area.

7 is a result of rescanning the original hard copy of FIG. 6 with a high resolution scanner. It's easy to recognize the color phrase copy. The higher the scanning resolution, the more pixels per unit area, so the color looks more pronounced. This is the biggest difference of the present invention compared to the existing invention.

8 and 9 show other examples of halftone cells and spots. Subtractive juxtaposition blending characteristics and mixed color results can be implemented in a variety of halftone cells and spots according to the characteristics of the printer based on the complementary color characteristics of gray tones.

Accordingly, the present invention achieves the effect of performing a very low cost hard copy copy protection function using a general printer and a plain paper.

In addition, the present invention achieves the effect of distinguishing the original and the copy even if the scanning resolution is increased.

In addition, the present invention achieves the effect of reducing the illegal copy by inserting a hard copy copy protection pattern for every page or important picture of the offline so that the phrase 'copy' appears when illegal copying.

The present invention is not limited only to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

Claims (11)

In the method for generating a copy protection pattern of a hard copy document, (1) generating and storing a binary pattern map, which is a copy protection pattern, for each output device; (2) generating a half tone cell and a spot using the binary pattern map selected by the user; And (3) generating a hard copy copy protection pattern using the generated half tone cells and spots and combining the document with a document; Hard copy copy protection method characterized in that consisting of. The method of claim 1, wherein the copy protection pattern, Hard copy copy protection method characterized in that the character or company logo stored in the form of a bitmap or picture file. The method of claim 1, wherein the hard copy copy protection pattern, And a half tone dot (or cell) inserted into the half tone cell and a half tone cell having a predetermined size. The method of claim 3, wherein the half tone cell and the half tone dot, A hard copy copy protection method, characterized by a combination of dots of different colors formed by a juxtaposition subtraction mixing method. The method of claim 3, wherein the half tone cell and the half tone dot, Hard copy copy protection method characterized in that the color of the complementary color scheme is formed by combining the dots of different colors. Storage means for storing information on a plurality of output devices and a plurality of binary pattern map information matched with the output device information; Output the binary pattern map information of the storage means on the screen for the user to select, generate a hard copy copy protection pattern using the binary pattern map information selected by the user, and generate a hard copy generated by the user Control means for inserting a hard copy copy protection pattern into the document to generate a hard copy copy protection document; Output means for outputting a hard copy document having the hard copy copy protection pattern in response to the control of the control means; And Input means for outputting a hard copy copy protection pattern selection signal to the control means according to a user's operation; Hard copy copy protection system, characterized in that configured to include. The method of claim 6, wherein the control means, Hard copy copy protection system, characterized in that for generating a half tone cell and a spot using the binary pattern map selected by the user, and a hard copy copy protection pattern using the generated half tone cell and spot . The method of claim 7, wherein the copy protection pattern, Hard copy copy protection system, characterized in that the character or company logo stored in the form of a bitmap or picture file. The method of claim 7, wherein the hard copy copy protection pattern, A hard copy copy protection system, comprising a half tone cell having a predetermined size and a half tone dot (or cell) inserted into the half tone cell. The method of claim 9, wherein the half tone cell and the half tone dot, A hard copy copy protection system, characterized by a combination of dots of different colors formed by a juxtaposition subtraction mixing method. The method of claim 9, wherein the half tone cell and the half tone dot, Hard copy protection system, characterized in that formed by combining the colors of different colors by the color complementary method.