JPH0787297A - Picture forming device with tracking function - Google Patents

Abstract

PURPOSE:To exactly track a device by which forgery is committed by preventing the alteration of a tracking pattern (microcharacter code). CONSTITUTION:A picture forming device with a tracking function in which the tracking pattern for specifying a device in which picture formation is operated is added to inputted picture data, is provided with a tracking pattern outputting means which changes the synthesizing position of the tracking pattern on the picture data by each original or by each picture data for one sheet, and outputs the tracking pattern, and synthesizing means which synthesizes the tracking pattern outputted from the tracking pattern outputting means with picture data. Thus, the synthesizing position of the tracking pattern on outputted recording paper can fluctuate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention adds a legible specific tracking pattern to a copy-prohibited object such as paper money or securities, and outputs the copy from the pattern. The present invention relates to an image forming apparatus with a tracking function such as a digital color copying machine that can identify the apparatus.

[0002]

2. Description of the Related Art In recent years, with the widespread use of full-color copying machines and the improvement in image quality of output images, the social problem of counterfeiting copy prohibited items such as banknotes and securities has been further highlighted. For such a problem of abuse copying,
For example, there is an "image forming apparatus" disclosed in Japanese Patent Laid-Open No. 4-294682. This is for forming an image by adding a specific pattern of a color that is hardly recognized by the human eye to an image signal.
Fine patterns such as codes are specified patterns (tracking patterns)
As a result, the device can be specified and the person who finally made the counterfeit copy can be traced.

[0003]

However, according to the conventional image forming apparatus as described above, a fine character code (tracking pattern) that cannot be easily identified by human eyes is added to the image data to form an image. The image forming apparatus can be specified by analyzing the added fine character code when the abuse copying is performed. Therefore, similarly analyze the added fine character code. Therefore, there is a problem that it is possible to tamper with the fine character code to make it impossible to identify the device that has formed the image.

For example, the image data is loaded into a computer, the fine character code is analyzed, and the position of the fine character code on the image data is specified. Next, by encoding a fine character for falsification at the position of the identified fine character code, the fine character code for identifying the original image forming apparatus can be altered to make it unidentifiable.

The present invention has been made in view of the above, and it is an object of the present invention to prevent tampering with a tracking pattern (fine character code) and to reliably track a forged device. To do.

[0006]

In order to achieve the above-mentioned object, the present invention provides an image forming with a tracking function for adding a tracking pattern for specifying an image forming apparatus to input image data. In the apparatus, the combining position of the tracking pattern on the image data is changed for each one document or each image data for one sheet, and the tracking pattern is output from the tracking pattern output means and the tracking pattern output means. An image forming apparatus with a tracking function provided with a combining means for combining a tracking pattern and image data.

The tracking pattern output means changes the combining position of the tracking patterns at a predetermined cycle in one document or one image data.

Further, in order to achieve the above object, the present invention provides a dither in an image forming apparatus with a tracking function, which adds a tracking pattern for specifying an apparatus that has formed an image to input image data. Start position of pattern is 1
Change for each original or for each image data
Dither pattern output means for outputting a dither pattern,
An image forming apparatus with a tracking function provided with dither processing means for performing dither processing on image data using a dither pattern output from a dither pattern output means.

The dither pattern output means changes the start position of the dither pattern at a predetermined cycle in one original or image data for one sheet.

[0010]

In the image forming apparatus with the tracking function according to the present invention, the combining position of the tracking pattern on the image data is changed for each original or for each image data of one sheet, and the tracking pattern and the image data are combined. Then, the synthetic position of the tracking pattern is changed.

Further, the image forming apparatus with the tracking function according to the present invention dithers the image data by using the dither pattern in which the starting position of the dither pattern is changed for every one original or every one image data for every predetermined period. Processing is applied to change the density of the tracking pattern.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an image forming apparatus with a tracking function of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the main configuration of the image forming apparatus with a tracking function of this embodiment. In the figure, 1
An image reading unit 01 reads document information as image data by scanning or sequentially from a storage unit such as a memory.
Reference numeral 102 is an image processing unit that executes a predetermined processing process (described later) on the image data read by the image reading unit 101, and 103 is an image that outputs the image data processed by the image processing unit 102 to recording paper or the like. It is a recording unit.

Next, the operation will be described. The image data read by the image reading unit 101 is the image processing unit 10.
2 is input, various image processing is executed, and then output to the image recording unit 103. The image recording unit 103 outputs the image data on recording paper.

FIG. 2 is a block diagram showing a schematic configuration of the image processing unit 102. In the figure, 201 is RGB
A scaling processing unit for independently performing main scanning scaling processing for each data signal of the image data signal, 202 is an MTF correction for the RGB image data signal in order to correct blurring of a lens optical system (not shown) RGB filter for executing (sharpening) processing, 203 is an RGB γ correction unit for executing γ correction processing such as gray balance of RGB image data signals, and 204 is RG.
A processing unit 205 executes various processing such as mirror processing, italic processing, shadowing processing, paint processing, moving processing, etc. on the B image data signal as necessary, and 205 is based on a primary masking equation. The color correction unit performs color conversion processing for converting the data system from the RGB image data signal to the YMCK image data signal.

Reference numeral 206 denotes a γ correction unit that executes γ correction processing according to the γ characteristic of the image recording unit 103, and 207 executes filtering processing such as smoothing or sharpening according to the MTF characteristic of the image recording unit 103. A dither processing unit 209 is a tracking pattern unit that adds a tracking pattern to the image signal output from the dither processing unit 208.

Further, the image processing unit 102, as shown in the figure,
It can be connected to a computer 211 which is an external device via an I / F (interface) 210. The configuration is such that RGB system data or YMCK system data can be input / output from the computer 211 via the I / F (interface) 210.

Next, the operation of the image processing unit 102 will be described. The RGB image data is subjected to the main scanning scaling processing independently for each image data signal in the scaling processing unit 201, the MTF correction (sharpening) processing is executed in the RGB filter 202, and the RGBγ correction unit 203 is executed. , Γ correction processing such as gray balance is executed, various processing processing such as mirror processing and italic processing is executed in the processing processing unit 204, and the RGB image data signal is converted into the YMCK image data signal in the color correction unit 205. Convert the data system.

After that, the YMCK image data is YMCK.
In the γ correction unit 206, γ correction processing is executed according to the γ characteristic of the image recording unit 103, and the YMCK filter 207
In, a filtering process such as smoothing or sharpening is executed in accordance with the MTF characteristic, and a dither processing unit 208 executes a halftone process to convert each signal of YMCK into Y ′,
Dither processing for converting into M ′, C ′, and K ′ color signals is executed, and a tracking pattern is added in the tracking pattern unit 209. The YMCK image data combined with the tracking pattern is output to the image recording unit 103.

On the other hand, even when image data is input from the computer 211 via the I / F (interface) 210, the color correction unit 205, the γ correction unit 206,
After predetermined processing is performed via the YMCK filter 207, the dither processing unit 208, and the tracking pattern unit 209,
The tracking pattern is output to the image recording unit 103 as YMCK image data combined.

FIG. 3 is a block diagram showing a schematic structure of the tracking pattern unit 209. In the figure, 301 is
The counter initial value is set to a different value for each copy (each image data for one sheet) in synchronization with the main scanning synchronization signal, and 0 to 255 are repeatedly counted by the pixel clock signal, and A ₀
It is a main scanning counter that outputs the signals A to A ₇ . In addition,
The LSB in this case is A ₀ .

Reference numeral 302 is a sub-scanning direction counter that outputs a signal of A _{0 to} A ₇ by repeatedly counting 0 to 255 by the line synchronizing signal without synchronizing with the sub-scanning synchronizing signal. In this case, the LSB is A ₀
Is.

Reference numeral 303 is a selector connected to the output side of the main scanning counter 301, and 304 is a selector connected to the output side of the sub-scanning direction counter 302. Also,
Inputs A of the selectors 303 and 304 are inputted with respective outputs of the main scanning counter 301 and the sub-scanning direction counter 302, and an input B is inputted with an address signal from a CPU (not shown). There is. Also, output Y
Is configured to select whether to output the input A or the input B from the CPU.

305 has a capacity of 2 Kbytes, addresses A _{0 to} A ₁₃ , and selectors 303 and 30.
4 is a memory in which each output of 4 is connected to the input side. Further, WE of the memory 305 inputs a memory line signal from the CPU, D ₁ is a data input, and inputs data from the CPU. D ₀ is a data output and CP
It is configured to output data from U. When WE is HIGH, the memory write operation causes the data write of D ₁ corresponding to the addresses A _{0 to} A ₁₃ . When WE is LOW, the memory read operation outputs data from D ₀ corresponding to addresses A _{0 to} A ₁₃ .

Reference numeral 306 is a synthesizing unit for synthesizing the image data and the tracking pattern (fine character code). Both outputs of the main scanning direction counter 301 and the sub-scanning direction counter 302 are input to the input D of the synthesizing unit 306, and the EX-O
AND of the output of the EX-OR gate 307 and the output D _{0 of the} memory 305 for executing R (exclusive OR) logic processing
By connecting the output line of the AND gate 308 which executes logical processing, and by inputting image data of YMCK to IMGIN · YMCK, both input data are combined and output from IMGOUT · YMCK. There is. Note that the composition by the composition unit 306 is O
R synthesis, additive synthesis, or another synthesis method is used. Alternatively, only a specific color (for example, yellow that is difficult to visually recognize) may be combined.

Next, the operation of the tracking pattern unit 209 will be described. First, before starting the copying process, tracking pattern data is written in the memory 305 from a CPU (not shown). After that, when the copying process is started, the tracking pattern data stored in the memory 305 is read by the count values of the main scanning direction counter 301 and the sub scanning direction counter 302. In addition, EX-OR gate 3
When the LSBs of the main-scanning direction counter 301 and the sub-scanning direction counter 302 input to 07 match,
The input level becomes HIGH, and tracking pattern synthesis is permitted.

The output level of the EX-OR gate 307 is H.
When IGH and the output D _{0 of the} memory 305 is HIGH, the tracking pattern data is output from the AND gate 308 to the combining unit 306. The synthesizing unit 306 uses the memory 3
The tracking pattern data No. 05 is combined with the image data as a tracking pattern and output.

Here, the main scanning counter 301 sets a different value for each copy as the counter initial value and starts counting, and the sub-scanning direction counter 302 counts the line synchronization signal. Therefore, the main scanning direction counter 301 The LSBs of the sub-scanning direction counter 302 match at different timings for each copy. In other words, EX-O
The tracking pattern synthesis is permitted by the R gate 307 at different timings for each copy (each time image formation is performed), and even when the same original is copied, the tracking pattern is formed at a different position for each output recording sheet. Will be done. FIG. 4 is an explanatory diagram showing how the position of the tracking pattern output on the recording paper changes (that is, is not constant).

By the above operation, the position of the tracking pattern changes in the output image which is formed and output. Therefore, for example, even if the position of the tracking pattern (fine character code) on the output image is specified, it becomes difficult to match the position of the tracking pattern with the position of the fine character code for tampering, and thus the tracking pattern is tampered with. Will be difficult to do. That is, it is possible to prevent the tracking pattern (fine character code) from being tampered with and to reliably track the counterfeit device.

In the present embodiment, in addition to the processing of the tracking pattern section 209, the dither processing section 208 also changes the start position of the dither pattern for each copy and outputs the dither pattern. This makes it even more difficult to tamper with the tracking pattern.

In the dither processing section 208, an XY counter (not shown) is used to sequentially and repeatedly use the dither pattern (dither matrix). Therefore, by controlling the XY counter of the dither pattern, The start position of the dither pattern can be changed.

In the Y counter, the counter initial value set in synchronization with the sub-scanning synchronizing signal is set to a different value for each copy. However, it is the same for each color of YMCK. Further, in the X counter, the counter initial value set in synchronization with the main scanning synchronization signal is set to a different value for each copy. However, it is the same for each color of YMCK.

By doing so, since the start position of the dither pattern differs for each copy, if a fine character code such as a tracking pattern is output from the computer, the density control cannot be performed, and it is difficult to tamper with the computer. Become.

Therefore, as described above, in addition to the position of the tracking pattern output on the recording paper fluctuating, the starting position of the dither pattern differs for each copy, which makes it even more difficult to tamper with the tracking pattern.

In this embodiment, in the main scanning direction counter 301, the main scanning position of the tracking pattern is set by synchronizing the main scanning synchronizing signal and setting the counter initial value to a different value for each copy. Although different for each copy, the number of pixel clock signals for one line is Nx + M (where N is the period of the tracking pattern, M is a certain constant, and x is positive) without synchronizing with the main scanning synchronization signal. Integer)
The position of the tracking pattern may be shifted by M pixels for each line. In this case, for example, since M pixels are shifted between the L-th line and the (L + 1) th line, the tracking pattern data may be written in the memory 305 in consideration of the M-pixel shift in advance.

Further, in the main scanning direction counter 301, the upper 3 bits may be synchronized without synchronizing the lower 3 bits.

Further, in this embodiment, the sub-scanning direction counter 302 does not synchronize with the sub-scanning synchronization signal but repeatedly counts 0 to 255 by the line synchronization signal, so that the sub-scanning position of the tracking pattern is copied. Although different for each copy, the same effect can be obtained by setting the counter initial value to a different value for each copy in synchronization with the sub-scanning synchronization signal.

In this embodiment, the tracking pattern section 20
In 9 and the dither processing unit 208, the combining position of the tracking pattern or the starting position of the dither pattern is changed for each copy, but it may be changed for each original. Needless to say, the change of the combining position of the tracking pattern or the start position of the dither pattern at this time is not performed regularly, but is performed randomly.

[0039]

As described above, according to the image forming apparatus with the tracking function according to the present invention, the tracking function for adding the tracking pattern for specifying the image forming apparatus to the input image data. In the attached image forming apparatus, the tracking pattern output means for changing the composite position of the tracking pattern on the image data for each one document or each image data for one sheet, and the tracking pattern output means and the tracking pattern output means Since the synthesizing means for synthesizing the output trace pattern and the image data is provided, it is possible to prevent the trace pattern (fine character code) from being tampered with, and to reliably trace the forged device.

Further, according to the image forming apparatus with the tracking function of the present invention, in the image forming apparatus with the tracking function, which adds the tracking pattern for specifying the apparatus that has formed the image to the input image data, Dither pattern output means for changing the start position of the dither pattern for each original or for each image data of one sheet, and image data using the dither pattern output from the dither pattern output means Since the dither processing means for performing the dither processing is provided, it is possible to prevent tampering with the tracking pattern (fine character code) and to reliably track the forged device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of an image forming apparatus with a tracking function according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an image processing unit shown in FIG.

FIG. 3 is a block diagram showing a schematic configuration of a tracking pattern unit shown in FIG.

FIG. 4 is an explanatory diagram showing how the position of a tracking pattern output on a recording sheet changes (that is, is not constant).

[Explanation of symbols]

 102 image processing unit 208 dither processing unit 209 tracking pattern unit 301 main scanning counter 302 sub-scanning counter 303 selector 304 selector 305 memory 306 combining unit

Claims (4)

[Claims] 1. An image forming apparatus with a tracking function for adding a tracking pattern for specifying an apparatus that has formed an image to input image data, and a composite position of the tracking patterns on the image data is one. And a synthesizing unit for synthesizing the tracking pattern output from the tracking pattern output unit and the image data, which is changed for each original or for each image data of one sheet. An image forming apparatus with a tracking function, which is provided. 2. The tracking function according to claim 2, wherein the tracking pattern output means changes the combining position of the tracking patterns at a predetermined cycle in one document or image data of one sheet. Image forming apparatus. 3. An image forming apparatus with a tracking function, which adds a tracking pattern for specifying an apparatus that has performed image formation to input image data, in which the starting position of the dither pattern is set for each original or Dither pattern output means for changing the image data for one sheet to output a dither pattern, and dither processing means for performing dither processing on the image data using the dither pattern output from the dither pattern output means. An image forming apparatus with a tracking function, which is provided. 4. The tracking function according to claim 3, wherein the dither pattern output means changes the start position of the dither pattern at a predetermined cycle in one document or image data for one sheet. Image forming apparatus.