CN106708449B

CN106708449B - negative color image watermark-based anti-copying method in monochrome printing

Info

Publication number: CN106708449B
Application number: CN201611268150.6A
Authority: CN
Inventors: 王亮; 高睿; 王哲敏; 郁建; 李文龙; 杨如峰
Original assignee: Avicit's Science And Technology Ltd Co
Current assignee: Avicit's Science And Technology Ltd Co
Priority date: 2016-12-31
Filing date: 2016-12-31
Publication date: 2019-12-17
Anticipated expiration: 2036-12-31
Also published as: CN106708449A

Abstract

The invention relates to an anti-copying method based on negative color image watermarks in monochrome printing, which designs and manufactures a watermark pattern bitmap, carries out negative color superposition operation on an original text and the watermark pattern locally, and directly transmits a superposed and synthesized file to a printing module for normal printing. The printing driver processes bitmap processing on input original text information, when the original text information and a preloaded watermark pattern bitmap are subjected to negative color superposition, the watermark resolution takes the resolution of the original watermark pattern bitmap as a reference, the watermark pattern bitmap is subjected to equal proportional scaling, the negative color-based superposition is performed after matching, a synthetic watermark pattern bitmap for outputting is generated after superposition, and a printing operation is performed on a received final printing output file by a printing module.

Description

negative color image watermark-based anti-copying method in monochrome printing

Technical Field

The invention relates to an anti-copying method based on negative color image watermark in monochrome printing, in particular to the fields of government, enterprises, commerce and the like, which is suitable for preventing unauthorized pressers and users in the environment with higher protection requirements on paper medium sensitive documents.

Background

after the traditional paper file is printed and manufactured, the problems that the file is copied in an unauthorized mode or the copyright information cannot be determined after the file is copied cannot be effectively solved. The method has the advantages that technologies such as printing and overlaying technology based on watermarks, bar code overlaying technology and digital watermark protection appear on the market, gray level printing is used as a main means for the technologies, watermark information is stored in a user-defined area of an original, the method can only play an effective protection role on the original, and the method has the following problems: (1) in the traditional watermark, a gray watermark template (4.1 in fig. 4) with 30% -70% of the color depth of the current character is used for overlaying the template below the character for displaying, and the method is generally applied. Because the ink amount of the watermark is less than that of the character part and the color is lighter, the watermark becomes fuzzy or even fades and cannot be identified after the original manuscript is copied for many times, thereby losing the protection effect on the original manuscript; (2) although the barcode overlay technology can still clearly identify after being copied for multiple times, the barcode must be printed on a blank part (4.3 in fig. 4) of the document, and if the barcode is overlaid in the text, the readability of the original text and the identifiability of the barcode are seriously affected, so that the watermark protection cannot prevent a user from copying the barcode after covering the barcode during copying; (3) the digital watermark superposition technology has the same problem as the traditional watermark, the digital watermark hidden in the original document can not be accurately extracted finally after being copied for multiple times, the digital watermark algorithm technology is complex, the implementation cost is high, and the protection effect on the original document is good. (4) The traditional process of adding the watermark does not analyze the original text, and if the watermark pattern with the depth consistent with the ink amount of the text is used, the text is easily excessively shielded, so that the readability of the original text is influenced.

In summary, there is an urgent need for a simple method that can still display watermarks after paper documents are copied for many times at a low cost, and that can effectively ensure the integrity and reliability of paper document watermark marks in the copying process.

Disclosure of Invention

The invention solves the problems: the defects of the prior art are overcome, the negative color image watermark-based anti-copying method applied to monochrome printing is provided, and the color depth of the watermark is the same as the foreground color of characters (4.2 in figure 4) by adopting an algorithm of superimposing negative color watermark images. The method ensures that the definition degree of the watermark is always consistent with the characters after the paper medium document is copied on the premise of ensuring the readability of the original text, the watermark does not disappear due to the fading of the color after the paper medium document is copied for many times, and finally the high robustness of the document full life cycle protection is achieved.

The technical scheme of the invention is as follows: the negative color image watermark-based anti-copying method in monochrome printing comprises the following steps:

S11, designing and manufacturing the watermark pattern bitmap applied to the technology by using a computer or hand-drawing mode, wherein the initial resolution of the watermark pattern bitmap is consistent with the default printing resolution, so that the operation in the bitmap superposition process (2.6 in figure 2) is simplified, the efficiency is improved, and the printing period is shortened.

After the relevant printing driver is equipped, the original text and the watermark are locally overlapped (2.6 in fig. 2), and then the composite file is directly transmitted to a printing module (2.7 in fig. 2) for normal printing (2.8 in fig. 2). This has the advantage that no watermark pattern remains in the printing device to avoid leakage of watermark information.

The print driver of S12 can perform bitmapping on the input text, and superimpose it with the preloaded watermark pattern bitmap based on negative color (e.g. 2.6 in fig. 2). If the resolutions are not consistent, the watermark pattern bitmap is scaled (2.5 in fig. 2, as described in the scaling method) in an equal proportion by taking the resolution of the original text bitmap as a reference, and the watermark pattern bitmap is overlapped based on the negative color after being matched with the original text bitmap (2.6 in fig. 2). The composite bitmap for output is generated after superposition (4.2 in fig. 4) and transmitted to the print module (2.7 in fig. 2).

The S13 print module does not distinguish the print operation (2.8 in fig. 2) on the received final print output file (composite bitmap) from the conventional print process. The compatibility of the technology and the traditional printer is greatly guaranteed, the realization difficulty is reduced, the printed result is the watermark file with the negative color, and the use safety of the original text is protected.

S11, designing and manufacturing a watermark pattern bitmap by using a computer or a hand-drawing mode, wherein the initial resolution of the watermark pattern is consistent with the default printing resolution, so that the operation in the process of overlaying the watermark pattern bitmap is simplified, the efficiency is improved, and the printing period is shortened; related printing drivers are equipped, the original text and the watermark pattern are subjected to superposition operation based on negative color locally, and the superposed file is directly transmitted to a printing module for normal printing, so that the watermark pattern is not remained in printing equipment, and watermark information is prevented from leaking;

s12 print driver processes the input original text information into bitmap, and superimposes the original text bitmap and the pre-loaded watermark pattern bitmap based on negative color, if the resolution is not consistent, then uses the original text pattern bitmap resolution as the standard, scales the watermark pattern bitmap in equal proportion, makes the watermark pattern bitmap match with the original text bitmap and then superimposes based on negative color, after superimposing, generates the synthetic watermark pattern bitmap for output, and transmits it to the print module;

The printing operation of the S13 printing module on the received final printed output file is the same as that of the traditional printing process, so that the compatibility of the technology and traditional printing equipment is greatly guaranteed, the realization difficulty is reduced, the printing result is a watermark file based on negative color, and the use safety of the original text is protected.

In the steps S11 and S12, the watermark pattern is used by using a template, the format design of the template and its default parameter settings, the common format is a4,300dpi, and the default resolution is 2480 × 3508.

in the steps S11 and S12, the process of superimposing based on the negative color is as follows: the original bitmap (bitmap formed according to 3.1 naming rule) and the watermark pattern bitmap (bitmap formed according to 3.2 naming rule) are processed by XOR operation on the points with the same angle sign, and the corresponding point a behavioris stored into the composite bitmap, as shown in 3.3 (namely a behavior) in FIG. 3_nm⊕b_nm) Is a composite bitmap (fig. 44.2) generated as a result of the dot-bit overlay, transmitted to the print module in the process of 2.7 in fig. 2.

If the length-width ratio of the original text format is the same as that of the watermark template, the watermark is stretched or shrunk in equal proportion by taking a diagonal line as a reference, so that the watermark is the same as the resolution of the original text and the position of the watermark is kept as unchanged as possible. If the original format aspect ratio is different from the watermark template aspect ratio, more than the long or wide portions of the watermark pattern are cut off and then scaled.

The generated document containing the negative color image-based watermark can not fade the watermark effect due to multiple times of copying, and the identification of the original watermark is reduced.

The method is suitable for the negative image watermark printing scene of the black-white monochromatic paper medium.

the method is also suitable for the negative color image-based watermark printing scene with the characters in single color and the background in single color.

The invention is not limited to the use scene of the printer, and also comprises other scanning, printing and copying integrated machines and copying machine type paper medium output equipment.

compared with the prior art, the invention has the following advantages:

(1) Because the printing content is not black or white, the definition of the watermark is not changed with the number of copying times, and the validity period of the watermark is consistent with the storage period of the original text. The method of removing the watermark by depending on multiple copies is avoided.

(2) The watermark does not enable the original text and the watermark to be mutually covered, so that the individual text content does not have the shielding effect, and the higher readability is kept.

(3) The realization method is low in difficulty, the original file is better, and the robustness is still high after the original file is copied for multiple times.

(4) The requirement on printing equipment is low, and the received document task is the same as the traditional task.

Drawings

FIG. 1 is a schematic view of the solution of the present invention;

FIG. 2 is a flow chart of an implementation of the present invention;

FIG. 3 is a process of a superposition XOR algorithm;

Fig. 4 watermark implementation versus example diagram.

Detailed Description

The bitmapped description in this invention is: original text bitmap and watermark pattern bitmap being combined bitmap

Conventional description: original text + watermark

The printing apparatus: finger output device

The print driver: program responsible for overlay Process

A printing module: the output part is referred to as a general term.

As shown in fig. 1, the method of the invention comprises the following steps:

At the stage of S11 (fig. 1), a default watermark pattern to be superimposed is manually designed as a preparation process. The default design parameters of the watermark are determined according to the format of the common printing content, because the format of the common printing content is A4 and 300dpi, the default watermark is produced according to the condition of 2480 × 3508, and the content is monochrome. The overlay process (2.6 in fig. 2) is much simpler and more efficient when the resolution of the watermark pattern bitmap matches the original text bitmap.

In the stage S12 (fig. 1), 2.1 in fig. 2 is a flow of inputting an original text without a watermark from a print drive entry and adding a watermark, and in the stage 2.2, bitmap processing is performed on the original text to make it a dot matrix data file. Then, the dot matrix data file is assigned and stored according to the point locations, as shown in fig. 3, 3.1 parts are local 2 x 2 pixel maps taken from the upper left corner of the original text, and each point location a_nmthe container is assigned a value (n is the row name, integer, increasing from 0; m is the column name, integer, increasing from 0). For example, the third row and the fourth column are a₂₃. The assignment content is assigned as 1 or 0 (black is 1, white is 0) according to whether the pixel point is black or not.

2.3 in fig. 2 is that in the print driver, the watermark pattern bitmap is loaded and then matched and compared with the 2.2 original text bitmap in 2.4 print driver, the watermark pattern bitmap at this time should be consistent with 3.2 part of the composition pattern in fig. 3, and then dot matrix data processing is carried out, 3.2 is the local 2 x 2 pixel map taken from the upper left corner of the watermark pattern bitmap, and the naming rule b_nmand a is as described above_nmAnd (5) the consistency is achieved.

In the comparison of 2.4 in fig. 2, if the original and watermark patterns have the same resolution, the original bitmap and watermark pattern bitmap can be fed directly into the 2.6 process.

In the comparison of 2.4 in fig. 2, if the original image and the watermark image have different resolutions, the watermark pattern bitmap is scaled according to the original bitmap resolution in 2.5, and the scaling method is as follows:

If the length-width ratio of the original text format is the same as that of the watermark template, the watermark is stretched or shrunk in equal proportion by taking the diagonal line as a reference, so that the resolution of the watermark is the same as that of the original text, and the relative position of the superposed part of the watermark is kept as unchanged as possible.

If the aspect ratio of the original format is different from that of the watermark template, the length or width of the watermark image is cut off to make the aspect ratio the same, and then the scaling process is performed. So that the resolution of the original text is the same and the relative position of the superimposed part of the watermark is kept as constant as possible.

This process causes the watermark pattern bitmap to generate a ready map with the same resolution as the original text, and enters the process 2.6 (fig. 2).

The superposition process (position adjusted here) is as shown in fig. 3, and the original text bitmap (bitmap formed according to 3.1 naming rule) and the watermark pattern bitmap (bitmap formed according to 3.2 naming rule) are processed by exclusive or operation on the points with the same angle sign, and the corresponding points a ≦ b are stored in the composite bitmap, at this time, the superposed points appear in the following four cases, and the specific processing method and explanation are as follows:

(a) when a is 0; b is 0. a ≧ b ═ 0. The original image white points correspond to the watermark image white points and are superposed into white points.

(b) When a is 1; b is 0. a ≧ b ═ 1. The original image white points correspond to the watermark image black points and are superposed into black points.

(c) When a is 0; b is 1. a ≧ b ═ 1. The black points of the original image correspond to the white points of the watermark image and are superposed into black points.

(d) When a is 1; b is 1. a ≧ b ═ 0. The black points of the original image correspond to the black points of the watermark image and are superposed into white points.

As in fig. 3 at 3.3 (i.e., a)_nm⊕b_nm) Is a composition generated by superimposing the results in point-by-pointThe actual effect of the bitmap (4.2 in fig. 4) superimposed is as 4.2 in fig. 4.

After superposition, the composite bitmap for output is generated (the effect is shown as 4.2 in fig. 4), and transmitted to the print module (2.7 in fig. 2).

At stage S13 (FIG. 1)

In the process 2.8 of fig. 2, the mode of the print instruction received by the print module is consistent with the mode of the conventional printing, which ensures that the compatibility of the technology and the conventional printer is greatly ensured, the implementation difficulty is reduced, and the printed result is a negative color-based watermarked file. The output result integrates the original text and the watermark into a whole, and immediately the printing process is finished, thereby realizing the protection of the use safety of the original text. And the printing equipment does not record the watermark information, so that the situation that the original text protected by the watermark is cracked due to the leakage of the watermark information is avoided.

Details not described in the present specification are prior art known to those skilled in the art.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be construed as the protection scope of the present invention.

Claims

1. An anti-copy method based on negative color image watermark in monochrome printing is characterized in that the color depth of the watermark is the same as the foreground color of characters by adopting an algorithm of the superposition of negative color watermark images, the definition degree of the watermark is always consistent with the characters after the paper medium document is copied on the premise of ensuring the readability of the original text, the watermark does not disappear due to the fading of the color of multiple copies, and finally the high robustness of the full life cycle protection of the document is achieved,

The method comprises the following specific steps:

S11, designing and manufacturing a watermark pattern bitmap by using a computer or a hand-drawing mode, wherein the initial resolution of the watermark pattern bitmap is consistent with the default printing resolution; and the relevant print driver is equipped, the superposition operation based on the negative color is carried out on the original text and the watermark pattern, and the superposed file is directly transmitted to the print driver in the step S12;

The S12 print driver processes the inputted original text information into bitmap, and carries out the superposition operation based on the negative color on the original text bitmap and the pre-loaded watermark pattern bitmap, if the resolution is not consistent, the resolution of the original text pattern bitmap is taken as the reference, the watermark pattern bitmap is scaled in equal proportion, the watermark pattern bitmap is matched with the original text bitmap and then superposed based on the negative color, and after superposition, the synthesized watermark pattern bitmap for output is generated and transmitted to the S13 printing module;

and S13, the printing module performs printing operation on the received final printed output file, the printing result is a negative color-based watermarked file, and the color depth of the watermark and the color depth of the text are always consistent after the watermarked file is copied for multiple times, so that the use safety of the watermark in the original text is protected.

2. the negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, characterized in that: in the steps S11 and S12, the watermark pattern is used by using a template, the format design of the template and its default parameter settings, the common format is a4,300dpi, and the default resolution is 2480 × 3508.

3. The negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, characterized in that: in the steps S11 and S12, the process of superimposing based on the negative color is as follows: and carrying out XOR operation on the original text bitmap and the watermark pattern bitmap and the points with the same logo, and storing the corresponding points a behavior.

4. The negative-color image watermark-based copy prevention method in monochrome printing according to claim 3, wherein: if the length-width ratio of the original text is the same as that of the watermark template, the watermark is stretched or shrunk in equal proportion by taking a diagonal line as a reference, so that the position of the watermark is kept as unchanged as possible while the resolution of the original text is the same, and if the length-width ratio of the original text is different from that of the watermark template, the scaling treatment is carried out after cutting off redundant long or wide parts in the watermark.

5. The negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, wherein: in step S12, the generated document containing the negative color image-based watermark does not fade the watermark effect due to multiple copies, and reduces the identification of the watermark in the original text.

6. the negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, wherein: the method is suitable for the negative-color image watermark printing scene of the black-white single-color paper medium.

7. The negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, wherein: the method is also suitable for negative color image watermark printing scenes with single-color characters and single-color backgrounds.

8. The negative-color image watermark-based copy prevention method in monochrome printing according to claim 1, wherein: the method is not limited to the use scene of the printer, and also comprises other scanning, printing and copying integrated machines and copying machine type paper medium output equipment.