JP2001346032A - Image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method and an image forming device capable of adding image data the copy and forgery of which are prevented to facilitate trace of a distribution route of an outputted print when an image is formed based on document data the forgery of which by copy is inhibited. SOLUTION: When PDL data of a confidential document to which additional information is added is inputted in a print data input part 1, a document image forming part 2 prepares document image data. An additional information extracting part 4 extracts the additional information consisting of latent image character strings and encoded information. A latent image forming part 5 prepares latent image character image data from the latent image character string, an additional information encoding part 6 makes the encoded information into error correction codes and prepares code data by referring to the latent image character image data. A pattern image forming part 8 prepares a pattern image from a dot pattern stored in a pattern storage part 7 on the basis of the code data. An image compositing part 10 composites the document image data with the pattern image superimposing them and the document image data with which the pattern image is composited is printed and outputted by an image forming part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image generating method and an image generating apparatus, and more particularly to an image generating method and an image generating apparatus for generating an image based on document data for which copy forgery is prohibited.

[0002]

2. Description of the Related Art With the recent spread of personal computers and higher performance of printers and copiers, illegal copying and improper copying of confidential documents such as family register copies and contracts have been made. Use is a problem.

Conventionally, in order to suppress such illegal copying and unauthorized use of confidential documents, special paper called copy forgery prevention paper has been used. The copy forgery prevention paper is a paper on which a special pattern in which warning characters and the like which are hidden when copied by a copier emerges, which is difficult to be seen by human eyes, is printed in advance. When a document printed on this copy forgery prevention paper is copied by a copier, warning characters such as "copy prohibited" appear prominently on the copy, so that psychological protection against the act of illegally copying is made. In addition to the deterrence, the warning character makes it possible to distinguish between the original and the compound.

A digital recording apparatus described in Japanese Patent Application Laid-Open No. Hei 7-231384 discloses a latent image embedding image in which a latent image to be visualized by copying is embedded in a background image by image processing, similarly to the above-described copy forgery prevention paper. To generate. In this apparatus, when copying and recording the image data read by the CCD, the latent image embedded image subjected to dither processing in which the latent image character portion and the background portion have different specific densities is superimposed on the main image. By matching, it is possible to obtain the same print as the case where the copy forgery prevention sheet is used by using the normal sheet.

[0005] However, merely raising the warning characters or the like does not make it possible to identify the person who committed the wrongdoing and take measures such as preventing recurrence. Therefore, in order to suppress unauthorized copying and unauthorized use of confidential documents, it is particularly important to add information that can track the outflow route of confidential documents to the printed image, such as which printer has been used to output. Become.

Such information can be embedded as a latent image in a background image by using a digital recording device described in Japanese Patent Application Laid-Open No. 7-231384. However,
When the latent image embedded in the background image is visualized by copying, it cannot be visualized unless the characters embedded as the latent image are large to some extent. For this reason, there is a problem that the length of a character string to be embedded is limited, and a large amount of information cannot be embedded in one image. Further, it is not suitable for embedding information such as information relating to privacy that is not desired to be exposed to the public in normal use. That is,
The information to be embedded is limited to information that can be visualized, and there is a problem that information necessary to reliably specify the outflow route of the confidential document cannot be added.

Japanese Patent Application Laid-Open No. 10-285385 proposes a recording medium output method for embedding information such as an IP address of a printer device and a print date and time into an image to be printed out, using a dot pattern that is difficult to identify visually. Have been. Since information such as an IP address is embedded in an image printed out using this method,
By analyzing these information, it is possible to specify the printer device that has output and the date and time when the output has been performed. Also IP
Since the information such as the address is added by a dot pattern that is hard to identify visually, the image quality and the like of the printed image are not impaired.

However, Japanese Patent Laid-Open No. 10-285385
In the method described in Japanese Patent Application Laid-Open Publication No. H08-157, a dot pattern is formed using yellow toner in order to make it difficult to visually discriminate, and thus the method lacks versatility such that this method cannot be applied to a black-and-white printer. There is. In addition, when a printed image is copied with a black-and-white copying machine, the dot pattern formed using yellow toner is not copied, so it is easy to delete the added information and it is difficult to track the outflow route. Problem.

Furthermore, although the illegal copying and unauthorized use of a confidential document can be suppressed by using the method and apparatus described above, the illegal copying and unauthorized use cannot be surely prevented. In order to prevent unauthorized copying and unauthorized use, it is necessary to provide the copier with a function that recognizes that the copy object is a confidential document whose copying is prohibited and prohibits copying. is there.

However, it is difficult for a copying machine to recognize a dot pattern or the like embedded in an image as a latent image. Also, if a machine readable code such as a bar code is added to an image and printed out, the copier can be recognized as a confidential document, but the position of the bar code in the printed image is determined. There is a problem that the added information can be easily deleted by copying without the barcode because it can be clearly identified.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to provide a method for generating an image based on document data in which forgery by copying is prohibited. It is an object of the present invention to provide an image generation method and an image generation apparatus capable of adding copy and forgery prevention image data that can easily track the distribution route of the image. Another object of the present invention is to add copy-forgery-prevention image data that can take measures to prohibit copying of an output print when generating an image based on document data in which forgery by copying is prohibited. It is an object of the present invention to provide an image generating method and an image generating apparatus capable of performing the above.

[0012]

In order to achieve the above object, an image generating method according to claim 1 is an image generating method for generating an image based on document data in which forgery by copying is prohibited, Based on predetermined information, generate copy-forgery prevention image data provided with a machine-readable code in one of a latent image portion and a background portion, and generate the copy-forgery prevention image data and the document data. Synthesize and
An image is generated based on the synthesized data.

In the image generating method according to the first aspect, based on predetermined information, copy forgery prevention image data in which a machine readable code is provided in one of a latent image portion and a background portion is generated. Since this machine readable code is not easily readable by a human, various information can be embedded in the copy forgery prevention image data, and the outflow route of the output print can be easily tracked.

Further, since the machine-readable code is easily readable by a machine, for example, the copying operation is prohibited by recognizing that the object to be copied in the copying machine is a document whose copying is prohibited. For example, it is possible to take measures to prohibit copying of output prints, for example, by providing a copying machine with a function to perform printing.

In addition, since copy forgery prevention image data and document data for which copy forgery is prohibited are combined and an image is generated based on the combined data, copy forgery prevention paper is not used and copy forgery prevention is not used. The same effect as using the prevention paper can be obtained.

In the above image generation method, the machine readable code is preferably copied by a copying machine.
Using the machine-readable code copied by the copying machine and the image not copied by the copying machine, copy-forgery prevention image data in which the latent image is embedded can be formed. For example, when a machine readable code is provided in a latent image portion, an image that is not copied by a copying machine is provided in a background portion to form copy forgery prevention image data. In this case, when the output print is copied by a copying machine, the background portion becomes white and the latent image portion is copied at a high density, so that the latent image is visualized. When a machine readable code is provided in the background portion, an image that is not copied by the copying machine can be provided in the latent image portion to form copy forgery prevention image data. In this case, when the output print is copied by a copying machine, the latent image portion becomes white and the background portion is copied at a high density, so that the latent image is visualized.

The predetermined information may include at least one of coded information for generating a machine readable code and latent image information, and may be added to document data and input. Preferably, the generated machine-readable code is composed of a plurality of patterns having substantially the same area and different shapes. By adding coded information and latent image information to the document data and inputting it, it is possible to change the coded information and latent image information according to the document data, and to track the outflow route of the output print. It can be even easier.

According to a fourth aspect of the present invention, there is provided an image generating apparatus in which the image generating method according to the first aspect is applied to an image generating apparatus. The image generating apparatus generates an image based on document data in which forgery by copying is prohibited. A generating device, input means for inputting predetermined information, and, based on the input information, copy-forgery-preventing image data provided with a machine-readable code in one of a latent image portion and a background portion. It is characterized by comprising a generating means for generating, and a synthesizing means for synthesizing the generated copy forgery prevention image data and the document data.

In the above image generating apparatus, the generating means can generate the copy forgery prevention image data after performing the error correction coding processing of the information. By performing the error correction coding process of the information, the decoding process of the copy forgery prevention image data including the machine readable pattern is facilitated.

[0020] The generating means may include an arrangement control means for controlling the machine readable code to be arranged in one of the latent image portion and the background portion. By providing such an arrangement control means, it is possible to arbitrarily select which of the latent image portion and the background portion is to be visualized,
The copy forgery prevention image data can be diversified.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a first embodiment of the image generating apparatus of the present invention. As shown in FIG. 1, the image generation apparatus includes a print data input unit 1, a document image generation unit 2, a document image buffer 3, an additional information extraction unit 4, a latent image generation unit 5, an additional information encoding unit 6, a pattern Storage unit 7, pattern image generation unit 8, pattern image buffer 9, image synthesis unit 10, and image formation unit (output device)
11.

A print data input unit 1 receives a PDL (Printer Descriptor) transmitted from an external computer or the like.
Document data (PDL data) described in an Ion Language is input. In the header of the PDL data, the IP (In) of the computer that transmitted the print job is included.
Internet Protocol) address, the name of the user who sent the print job, the name of the document file to be printed, the time stamp of the document to be printed, the confidential level set in the document file, the coded information such as the password set in the document file, and the A latent image character string to be embedded as an image is added as additional information. These pieces of additional information are added only to confidential documents or the like for which copying must be prohibited.

The document image generator 2 rasterizes PDL data to generate binary image document image data. The document image buffer 3 temporarily stores the document image data generated by the document image generation unit 2.

The additional information extracting section 4 extracts additional information added to the header of the PDL data from the PDL data input to the print data input section 1 and encodes the extracted additional information with a latent image character string. Decompose into information. The latent image generation unit 5 reads the latent image character string, raster-expands the read latent image character string, and generates a latent image character image data that is converted into a binary image. The additional information encoding unit 6 performs error correction encoding on the encoded information input from the additional information extraction unit 4,
With reference to the latent image character image data input from the latent image generation unit 5, the code conversion of the error correction coded information is performed to generate code data.

The pattern storage 7 stores three types of dot patterns shown in FIG. The three types of dot patterns will be described later. Pattern image generator 8
Selects a dot pattern corresponding to each value of the code data from the three types of dot patterns stored in the pattern storage unit 7 and generates a pattern image composed of the three types of dot patterns. The pattern image buffer 9 temporarily stores the pattern image generated by the pattern image generation unit 8.

The image synthesizing section 10 superimposes and synthesizes the pattern image read from the pattern image buffer 9 on the document image data read from the document image buffer 3.

The image forming section 11 prints out document image data in which a pattern image has been synthesized. In other words, the image forming unit 11 is configured by a printer that records document image data on paper and has a printer engine such as a xerography engine.

Next, the operation of the image generating apparatus according to the first embodiment will be described.

PD transmitted from an external computer or the like
When the L data is input to the print data input unit 1, the input PDL data is interpreted and raster-expanded by the document image generation unit 2, and the document image data converted into a binary image is stored in the document image buffer 3. You.

Further, the additional information added to the header portion of the PDL data by the additional information extracting unit 4 is extracted. P
If no additional information is extracted from the DL data,
A signal (not shown) indicating that no additional information has been extracted from the additional information extraction unit 4 is output from the latent image generation unit 5, the additional information encoding unit 6, the pattern image generation unit 8, and the image synthesis unit 1.
Sent to 0. The processing at each unit receiving this signal is not performed, and the document image data read from the document image buffer 3 passes through the image synthesizing unit 10 and is output to the image forming unit 11 as it is.

When the additional information is extracted from the PDL data, the extracted additional information is decomposed into a latent image character string and coded information by the additional information extracting unit 4. Of these, the latent image character string is output to the latent image generation unit 5, and the coded information is output to the additional information encoding unit 6.

When a latent image character string is input to the latent image generation unit 5, the input latent image character string is raster-expanded using a predetermined font, and binary image latent image character image data is converted. Generated. The font to be used has a relatively large number of points (for example, 48 points) set in order to exhibit the same effect as the above-described copy forgery prevention paper.
However, the latent image character image is converted into a binary image so as to satisfy the following equations (1) and (2).

Latent image character image resolution = printer resolution ÷ number of horizontal pixels of pattern .. (1) Number of vertical and horizontal pixels of latent image character image = number of vertical and horizontal pixels of document image ÷ number of horizontal pixels of pattern .. (2) For example If the printer resolution is 600 dpi, the number of horizontal pixels of the pattern is 12 pixels, and the number of vertical and horizontal pixels of the document image data is 4960 × 7015 pixels, the resolution of the latent image character image is 50 dpi and the number of vertical and horizontal pixels is 413. × 584 pixels. That is, one pixel of the latent image character image is set so as to correspond to one pattern size. The latent image character image data generated by the latent image generation unit 5 is output to the additional information encoding unit 6.

The additional information encoding unit 6 includes an additional information extracting unit 4
When the coded information is input from the CPU, and the latent image character image data is input from the latent image generation unit 5, the input coded information is subjected to error correction coding by the additional information coding unit 6. The error correction coded information is represented by bit strings of “0” and “1”. The bit string is read out one bit at a time, and the read bit string is placed in a two-dimensional array of a predetermined size (unit: two-dimensional array). Array). The outermost bits of the unit two-dimensional array are all set to bit 1 in order to facilitate positioning and cutting out of the code data.

The unit two-dimensional array is repeatedly arranged in the vertical and horizontal directions to form a two-dimensional array having a size corresponding to the number of pixels of the latent image character image. Thereafter, the pixels of the latent image character image data are referred to, and when the pixels of the latent image character image data are black pixels, the values of the elements of the two-dimensional array corresponding to the positions of the black pixels are forcibly copied. Is replaced with a value “2” for selecting a pattern that is difficult to reproduce. As described above, the code data (two-dimensional array data) that has been subjected to the error correction coding, rearranged into a two-dimensional array, and code-converted according to the latent image character image data is output to the pattern image generating unit 8.

Next, when the two-dimensional array data is input to the pattern image generation unit 8, one pattern is selected from the pattern storage unit 7 in accordance with the value of each element of the input two-dimensional array data. The read pattern is read. For example, if the value of the element is “0”, the pattern 0 shown in FIG. 2A is selected, and if the value of the element is “1”, the pattern 0 shown in FIG.
Pattern 1 shown in (B) is selected, and the element value is “2”.
If so, the pattern 2 shown in FIG. 2C is selected. Each read pattern is written to a corresponding position in the pattern image buffer 9.

By repeating the above processing for all the two-dimensional array data having a size corresponding to the number of pixels of the latent image character image, the pattern image buffer 9 is composed of the above three types of patterns and is the same as the document image data. Pattern image data of a size is formed and stored.

In the image synthesizing unit 10, when the document image data is read from the document image buffer 3 and the pattern image is read from the pattern image buffer 9, each pixel of both image data is synthesized by a logical sum operation, and Is output to the image forming unit 11.

The image forming section 11 prints out, on a sheet of paper, document image data obtained by synthesizing a pattern image by a printer engine provided inside the image forming section 11.

FIG. 3A shows an example of a document image printed and output as described above. In this example, a white document image is combined over the entire surface so that the latent image portion is clear.

FIG. 3A shows the entire document image printed out. The character "CO" in FIG.
The area “PY” is a latent image portion that emerges when copying is performed by a copying machine, and the surrounding area is a background portion. In this figure, the character "COPY" can be identified, but in practice, the character "COPY" in the latent image portion is difficult to identify.

FIG. 3C is an enlarged image of the area surrounded by the square in FIG. 3A. The printed document image is composed of patterns 0 to 2 and has a latent image portion. Pattern 2 is arranged inside, and pattern 0 or 1 is arranged in the background.

The patterns 0 to 2 have different shapes as described above, but the number of black pixels constituting each pattern is substantially the same, and the density when printed and output is the same regardless of the pattern arrangement. It is configured as follows. In fact, even though the number of pixels is the same due to the printer characteristics, the density differs slightly depending on the pattern, so that the number and pattern shape of the black pixels constituting each pattern are set so that the densities after print output match exactly. I have.

The patterns 0 and 1 arranged in the background portion are
As shown in FIGS. 2A and 2B, the pattern is a linear fine pattern, and has a characteristic that the pattern is reproduced when copied by a copying machine. On the other hand, the pattern 2 arranged inside the latent image portion is a pattern in which isolated dots are sparsely arranged as shown in FIG. 2C, and the pattern is reproduced when copied by a copying machine. Has difficult characteristics. For this reason, when the document image shown in FIG. 3A is copied by a copying machine, the background portion is copied at a high density, the image is missing inside the latent image portion, and as shown in FIG. A white "COPY" character appears on the object. (Second Embodiment) Next, a second embodiment of the present invention will be described. In the present embodiment, when copying is performed by a copying machine, the image of the background portion is lost, and the inside of the latent image portion is copied at a high density, so that the latent image portion is visualized.

Since the configuration is the same as that of the first embodiment except that the operations of the latent image generating section 5 and the additional information encoding section 6 are different, the description of the same portions will be omitted, and only the differences will be described.

In the present embodiment, the latent image generation unit 5 reads a latent image character string, rasterizes the read latent image character string into a binary image, and has a predetermined area at a predetermined position. To generate latent image character image data. By providing such a latent image area,
One or more unit two-dimensional arrays are always included in the latent image portion, and the coded information embedded in the pattern image can be decoded with high accuracy.

In the additional information encoding unit 6, the pixels of the latent image character image data are referred to. If the pixels of the latent image character image data are white pixels, a two-dimensional array corresponding to the positions of the white pixels is provided. The value of the element is forcibly replaced with a value “2” for selecting a pattern that is difficult to reproduce by copying.

FIG. 4C is an enlarged image of the area surrounded by the square in FIG. 4A. As described above, the value of the element of the two-dimensional array corresponding to the position of the white pixel is forcibly replaced with “2”, so that the pattern 0 or 1 is arranged inside the latent image portion and the background portion is Pattern 2 is arranged. For this reason, when the document image shown in FIG. 4A is copied by a copying machine, the inside of the latent image portion is copied at a high density, and the image is missing from the background portion, as shown in FIG. A black "COPY" character appears on the object. Further, as shown in the upper right of FIG. 4A, a rectangular latent image area having a predetermined area is added to a predetermined position of the latent image character image.

As described above, when a document image printed and output by the image generating apparatuses of the first and second embodiments is copied by a copying machine, an image of a character or the like embedded as a latent image emerges. Therefore, psychological deterrence against the act of illegally copying can be obtained, and the original image and the duplicated object can be distinguished from each other by the emerged image.

The pattern 0 corresponding to bit "0"
Is a diagonally slanted shape to the right, and the pattern 1 corresponding to the bit "1" is a diagonally slanted shape to the left. Can be identified. That is,
A machine readable code can be configured using these two types of patterns, and information such as the IP address of the printer and the output date and time can be embedded as a machine readable code in a document image. Note that pattern 1 may correspond to bit “0” and pattern 0 may correspond to bit “1”.

As described above, by embedding the machine readable code (digital code) in the document image, it is possible to specify the outflow route of the output print from the embedded information, and to copy even if illegally copied. The outflow path of the print output from the machine-readable code reproduced on the object can be easily tracked. Further, by embedding copy prohibition information that can be read by the copying machine as a machine readable code, the copy prohibition information can be detected on the copying machine side, and the copying machine can be prevented from copying. Further, since the machine-readable code cannot be easily read by a human, it is possible to embed information such as privacy-related information that is not desired to be exposed to human eyes in normal use.

Further, since the machine readable codes subjected to the error correction coding are used and a large number of such machine readable codes are repeatedly arranged on the entire screen, some of the machine readable codes are embedded by embedding a latent image or combining with a document image. Disappears,
The embedded information can be accurately decoded.

In the above description, the pattern image data is formed by the three dot patterns of the two patterns constituting the machine readable code and the other one pattern. However, if specific information can be displayed as the machine readable code. Often, the types of patterns are not limited to three. Further, the processing for generating the pattern image data may be configured to be executed by hardware or may be configured to be executed by software.

[0054]

According to the image generating method and the image generating apparatus of the present invention, when an image is generated based on document data for which copying forgery is prohibited, copy forgery prevention can be performed without using copy forgery prevention paper. There is an effect that the same effect as using paper can be obtained.

Further, when an image is generated based on document data in which forgery by copying is prohibited, copy-forgery-preventing image data that makes it easy to track the distribution route of the output print can be added. It works.

Further, when an image is generated based on document data in which forgery by copying is prohibited, copy forgery prevention image data capable of taking measures to prohibit copying of the output print may be added. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image generation device according to a first embodiment.

FIGS. 2A to 2C are diagrams showing three types of dot patterns stored in a pattern storage unit.

3A is a conceptual diagram showing an example of a printed document image, FIG. 3B is a conceptual diagram showing an image when FIG. 3A is copied by a copying machine, and FIG. FIG.

FIG. 4A is a conceptual diagram showing another example of a printed document image, FIG. 4B is a conceptual diagram showing an image when (A) is copied by a copying machine, and FIG. It is the elements on larger scale of A).

[Explanation of symbols]

 Reference Signs List 1 print data input unit 2 document image generation unit 3 document image buffer 4 additional information extraction unit 5 latent image generation unit 6 additional information encoding unit 7 pattern storage unit 8 pattern image generation unit 9 pattern image buffer 10 image synthesis unit 11 image formation Unit (output device)

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 5/91 P (72) Inventor Koji 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Works (72) Inventor Hiroyuki Kono 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Office F-term (reference) 5B057 AA11 CA18 CB16 CE08 CG07 5C052 AA11 FA02 FA03 FA09 FB05 FC02 FD06 5C053 FA04 FA07 FA13 GB05 GB12 LA16 AA14 BA06 BA09 5C077 LL14 MP05 PP23 PP43 PQ08 TT06

Claims (7)

[Claims] An image generating method for generating an image based on document data for which copying by forgery is prohibited, wherein a machine is provided on one of a latent image portion and a background portion based on predetermined information. An image generation method for generating copy forgery prevention image data provided with a readable code, combining the generated copy forgery prevention image data with the document data, and generating an image based on the combined data. 2. The copying / forgery prevention image data, when a machine readable code is provided in a latent image portion, an image which is not copied by a copying machine is provided in a background portion, and the machine readable code is provided in a background portion. 2. An image forming apparatus comprising:
The image generation method according to 1. 3. The apparatus according to claim 1, wherein the predetermined information includes at least one of coded information for generating a machine-readable code and latent image information, and is added to document data and input. Image generation method. 4. The image generating method according to claim 1, wherein the generated machine-readable code includes a plurality of patterns having substantially the same area and different shapes. 5. An image generating apparatus for generating an image based on document data in which forgery by copying is prohibited, comprising: input means for inputting predetermined information; and latent information based on the input information. Generating means for generating anti-counterfeiting image data provided with a machine-readable code in one of the image portion and the background portion; and synthesizing means for synthesizing the generated anti-counterfeiting image data and document data. Image generation device. 6. The image generation apparatus according to claim 5, wherein said generation means generates the copy forgery prevention image data after performing an error correction encoding process on the information. 7. The image generating apparatus according to claim 5, wherein said generating means includes an arrangement control means for controlling a machine readable code to be arranged in one of a latent image portion and a background portion.