JP2001309169A - Image processing apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of a conventional image processing unit that cannot have matched a level of a dot pattern added actually to an image resulting in obtaining a remarkable dot pattern of an image outputted from one unit and in causing a difficulty of extracting the dot pattern of an image outputted from other unit because the level of the dot pattern differs depending on an individual unit difference and a lapse of an operating time even when the level of the dot pattern to be added-on is kept the same. SOLUTION: A sample image to which 5 stages of add-on levels are set is outputted (S1), and a reader reads the sample image (S2). Then an add-on level α able to extract the dot pattern is discriminated (S3), and the add-on level α is set to an add-on section (S4).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and a control method thereof, for example, to an image processing apparatus for adding counterfeit tracking information to an image and a control method thereof.

[0002]

2. Description of the Related Art In recent years, the performance of image recording apparatuses such as color printers and color copying machines has been improved, and high quality images can be easily formed. Under such circumstances, securities such as banknotes (hereinafter referred to as "specific manuscripts")
Forgery may be counterfeited, and various anti-counterfeiting techniques have been considered. As one technique, there is a method of adding (add-on) a dot pattern indicating a machine number of an image processing apparatus to a color image to be printed. This dot pattern is generally added periodically to the entire image of the yellow component.

[0003]

Even if the level of the dot pattern to be added on is the same, the level of the dot pattern actually added to the image is different due to the individual difference of the apparatus and the lapse of the use time. For this reason, there is a problem that the dot pattern is conspicuous in an image output by a certain device, and it is difficult to extract the dot pattern in an image output by another device.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to add counterfeit tracking information according to individual differences between devices, elapse of use time, and the like.

[0005]

The present invention has the following configuration as one means for achieving the above object.

[0006] An image processing apparatus according to the present invention comprises: input means for inputting an image; adding means for adding forgery tracking information to the image; forming means for forming an image on a recording medium; Control means for causing the input means to read the sample image to which the forged tracking information has been added, and for controlling the addition condition of the forged tracking information by the adding means based on the read image.

The control method according to the present invention comprises: input means for inputting an image; adding means for adding forgery tracking information to the image;
And a control method of an image processing apparatus having a forming unit for forming an image on a recording medium, wherein the forming unit forms a sample image to which forgery tracking information is added, and the formed sample image is input to the input unit. And controlling the adding condition of the forgery tracking information by the adding means based on the read image.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Overview of Apparatus] FIG. 1 is an overview of an image processing apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 201 denotes an image scanner which processes a digital image signal obtained by reading a document image. Reference numeral 200 denotes a printer unit which performs full-color printing on a recording sheet of an image corresponding to a document image read by the image scanner unit 201.

In an image scanner section 201, a document 204 from which an image is read is placed between a document table glass 203 and a document pressing plate 202, and the document 204 is irradiated with light from a halogen lamp 205. The reflected light from the original 204 is
The light is guided to 207, and an image is formed on the three-line sensor 210 by the lens 208. The lens 208 has an infrared cut filter 2
31 are provided. Further, mechanically by a motor (not shown), the mirror unit including the mirror 206 and the halogen lamp 205 is driven at a speed V, and the mirror unit including the mirror 207 is driven at a speed V / 2 in the direction of the arrow, that is, the electric scanning of the three-line sensor 210. The document 204 is moved in a direction (sub-scanning direction) perpendicular to the direction (main scanning direction), and the entire surface of the document 204 is scanned.

A three-line sensor 210 comprising a three-line CCD
Reads color information of input light information, reads full color information red (R), green (G), and blue (B) color components, and sends the color component signals to the signal processing unit 209. Each of the CCDs constituting the three-line sensor 210 has a light-receiving element for 5000 pixels, and has a maximum width of an A3-size original that can be placed on the original platen glass 203.
mm) at a resolution of 400 dpi.

Reference numeral 211 denotes a standard white plate for correcting data read by the CCDs 210-1 to 210-3 of the three-line sensor 210. The standard white plate 211 is a white color that exhibits substantially uniform reflection characteristics with visible light.

A signal processing unit 209 electrically processes an image signal input from the three-line sensor 210 to generate a magenta image signal.
(M), cyan (C), yellow (Y), and black (Bk) color component signals are generated, and the generated MCYBk color component signals are sent to the printer unit 202. In addition, one color component signal of MCYBk is sent to the printer unit 200 for each original scan (scan) in the image scanner unit 201, and one printout is completed by a total of four original scans.

In the printer section 200, M, C, Y or Bk image signals sent from the image scanner section 201 are sent to the laser driver 212. The laser driver 212
The semiconductor laser device 213 is modulated and driven according to the input image signal. The laser beam output from the semiconductor laser element 213 scans the photosensitive drum 217 via the polygon mirror 214, the f-θ lens 215 and the mirror 216, and
An electrostatic latent image is formed on 217.

Reference numerals 219 to 222 denote developing units, each comprising a magenta developing unit 219, a cyan developing unit 220, a yellow developing unit 221 and a black developing unit 222. When the four developing units alternately contact the photosensitive drum 217, the electrostatic latent image formed on the photosensitive drum 217 is developed with a toner of a corresponding color to form a toner image. Reference numeral 223 denotes a transfer drum on which the recording paper supplied from the recording paper cassette 225 is wound, and transfers the toner image on the photosensitive drum 217 to the recording paper.

The recording paper on which the four color toner images of M, C, Y and Bk are sequentially transferred in this manner is fixed to the fixing unit 226.
, The toner image is fixed, and then discharged out of the apparatus.

The toners used in the present embodiment are yellow, magenta, cyan and black color toners, each of which has a styrene copolymer resin as a binder and a color material of each color dispersed therein.

[Signal Processing Unit] FIG. 2 is a block diagram showing a configuration example of the signal processing unit 209.

In FIG. 2, an image signal output from a full-color sensor (three-line sensor) 210 is input to an analog signal processing unit 11 where the gain and offset are adjusted.
An A / D (analog / digital) converter 12 converts each color component into an RGB digital image signal of, for example, 8 bits (0 to 255 levels: 256 gradations), and a shading correction unit 13 converts each color component into a reference white plate. Shading correction is performed using the signal obtained by reading 211. The shading correction is for correcting the sensitivity variation of each CCD sensor cell arranged in a line, and is for correcting the gain corresponding to each CCD sensor cell.

The digital image signal that has been subjected to shading correction is corrected for a spatial shift by a line delay unit 14. This spatial shift is caused by the lines of the full-color sensor 210 being arranged at a predetermined distance from each other in the sub-scanning direction. Specifically, B
The image signals of the R and G color components are line-delayed in the sub-scanning direction based on the color component image signals, and the phases of the three color component signals are synchronized.

The color space of the image signal output from the line delay unit 14 is converted by the input masking unit 15 into an NTSC standard color space. This conversion is performed by the matrix operation of Expression (1), and converts the color space of the image signal output from the full color sensor 210 determined by the spectral characteristics of the filter of each color component to the NTSC standard color space. Where Ro, Go, Bo: output image signal Ri, Gi, Bi: input image signal

The external input section 16 is an interface for inputting color image information displayed on a CRT display or the like by a computer or the like to the signal processing section 209.

The LOG converter 17 is constituted by, for example, a look-up table (LUT) of a ROM, and converts an RGB luminance signal output from the input masking unit 15 into a CMY density signal. The CMY density signal is line-delayed by the line delay memory 18. This is performed by a black character determination unit (not shown) based on an output of the input masking unit 15 for generating a signal such as UCR for controlling UCR, FILTER for controlling a filter, and SEN for controlling resolution, and for LOG conversion. The CMY image signal output from the unit 17 is delayed.

The CMY image signal stored in the line delay memory is
The masking / UCR unit 19 extracts the black component signal K.
The masking / UCR unit 19 further performs a matrix operation for correcting the color turbidity of the color material of the printer unit 200 on the YMCK image signal. The masking / UCR unit 19 outputs, for example, an 8-bit color component image signal in the order of M, C, Y, and K for each reading operation of the reader unit 201.

The image signal output from the masking / UCR unit 19 is corrected for the gamma characteristic of the printer unit 200 by the gamma correction unit 20 and output filter (spatial filter processing unit)
At 21, edge enhancement or smoothing processing is performed. The filtered image signal is L
The UT 22 performs conversion for matching the density of the original image with the density of the output image, and the add-on unit 23 adds a dot pattern based on the information for tracking forgery prevention.

The image signal output from the add-on section 23 is converted by a pulse width modulator (PWM) 212 into a pulse signal having a pulse width corresponding to the image signal level. This pulse signal is input to the laser driver 212 and drives the laser element 213.

[Dot Pattern] FIG. 3 is a diagram showing an example of a dot pattern generated and added on according to the present embodiment.

A dotted line shown in FIG. 3 is a line 40 in which a plurality of dots (hereinafter referred to as "add-on dots") constituting a dot pattern in the yellow plane are to be embedded.
1 (hereinafter referred to as “add online”), and reference numeral 402
Indicates an add-on dot. Add on dot 40
When “2” is enlarged, the image becomes as indicated by reference numeral 406.
Are arranged on both sides of the image signal, and one area 403 and 404 for subtracting a certain level from the image signal. Such add-on dots 402 are repeatedly formed in the image.

In this embodiment, a level 48 is set for both the + area and the − area. For example, the entire image has MCYK levels
When outputting a halftoned image of 80, the MCK level is set to 80 as it is, and the Y level is set to 80-48 = 32 in the minus area and 80 + 48 = 128 in the plus area.

The encrypted data, which is additional information obtained by integrating information transmitted from each device and information unique to the printer engine, is represented by the positional relationship of a plurality of add-on dots 402 in the main scanning direction. . For example, the distance between the add-on dot that first appears in the add-on and the add-on dot that appears next represents numerical information and / or character information.

As described above, the dot pattern added to the color image can be obtained by reading the color image with an image scanner or the like and extracting only the yellow plane.
If the dot pattern is analyzed, the machine number of the image processing device used for copying or printing the color image, the user ID,
Information such as network ID can be obtained.

If the add-on level is raised, the extraction of the dot pattern becomes easy. However, if the add-on level is too high, the dot pattern is conspicuous and is recognized as an image having a degraded image quality or an abnormal image. Conversely, if the dot pattern is made inconspicuous by lowering the add-on level, it becomes naturally difficult to extract the dot pattern. Therefore, by adding the add-on dot 402 at the lowest add-on level at which the dot pattern can be extracted, the dot pattern is made inconspicuous.

At this time, as described above, even if the level of the dot pattern to be added on is the same, the level of the dot pattern actually added to the image changes due to the individual difference of the apparatus or the lapse of the use time. For example, if there are image forming apparatuses A and B, apparatus A has a relatively short use time, and apparatus B has a considerable use time, the dot pattern formed by apparatus A has good reproducibility and the dot pattern extraction However, the reproducibility of the dot pattern formed by the device B is poor, and it is often difficult to extract the dot pattern. Therefore, if the add-on level is the same irrespective of the device, the dot pattern is conspicuous in the device A at the add-on level adapted to the device B, and the dot pattern is extracted in the device B at the add-on level adapted to the device A It may not be possible.

Therefore, in this embodiment, a sample image in which the add-on level is changed is formed, the sample image is read by a reader, and an appropriate add-on level is set in the apparatus. FIG. 4 is a flowchart showing a process for setting an add-on level, which is executed by a CPU (not shown) that controls the entire image processing apparatus.

In step S1, a sample image in which the add-on level shown in FIG. 5 is changed in five steps is output, and in step S2, this sample image is read by a reader. And
In step S3, the add-on level α (in FIG. 5, any of 32, 48, 64, 80, or 96) at which a dot pattern can be extracted is determined, and the add-on level α is set in the add-on unit 23 in step S4. Note that add-on level 3 shown in FIG.
2, 48, 64, 80, and 96 are examples, and are appropriately set in accordance with the characteristics of the apparatus and changes with time.

This makes it possible to adjust the add-on level for each device, and to add a dot pattern that is inconspicuous and can be reliably extracted without being affected by individual differences between devices or the lapse of use time. It becomes possible. It is desirable that the add-on level be adjusted periodically.

[0038]

[Modification] In the above embodiment, an example was described in which the arrangement of the dot patterns actually added on and the arrangement of the dot patterns of the sample image were the same. Originally, the add-on position of the dot pattern indicates counterfeit tracking information, and therefore differs for each device. Therefore, in the above example, the dot pattern arrangement of the sample image is different for each device.
However, since it is only necessary to be able to determine whether or not an added-on dot pattern can be extracted, it is not necessary for the dot pattern array of the sample image to represent counterfeit tracking information.For example, the regular pattern shown in FIG. A simple dot pattern arrangement can be used to facilitate the determination.

In the above embodiment, an example in which the add-on level is changed has been described. However, as shown in FIG. 7, the dot pattern size can be changed in three steps (for example, 6 × 2, 9
A sample image having a total of nine types of dot patterns in which the add-on level is changed in three stages (for example, 32, 48 and 64) is output. Then, the sample image is read by a reader, and a combination of an add-on level and a size at which a dot pattern can be extracted is determined. Note that the dot patterns that have been added on are less noticeable in the order shown in the table below. Therefore, the combination in which the dot pattern can be extracted and the lowest numerical value in the table below is set as the add-on level and size.

As described above, according to the present embodiment, a sample image in which a dot pattern is added on is output and read for each image processing apparatus, and an appropriate add-on level is set. It is possible to add a dot pattern that is inconspicuous and can be reliably extracted without being affected by the progress.

[0041]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to provide a storage medium (or a recording medium) recording a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. Also,
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the operating system (OS) running on the computer based on the instructions of the program code.
It is needless to say that a case in which the functions of the above-described embodiments are implemented by performing part or all of the actual processing.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

[0045]

As described above, according to the present invention,
Forgery tracking information can be added according to the individual differences of the apparatus or the elapse of the use time.

[Brief description of the drawings]

FIG. 1 is an outline view of an image processing apparatus according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a configuration example of a signal processing unit.

FIG. 3 is a diagram illustrating an example of a dot pattern generated and added on according to the embodiment;

FIG. 4 is a flowchart showing a process for setting an add-on level;

FIG. 5 is a diagram showing an example of a sample image in which add-on levels are assigned in five stages;

FIG. 6 is a diagram showing a sample image example of a regular dot pattern array;

FIG. 7 is a diagram showing an example of a sample image having a total of nine types of dot patterns in which the dot pattern size is changed in three stages and the add-on level is changed in three stages.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 1/387 G03G 21/00 554 5C077 F term (reference) 2C061 AP03 AP04 AQ06 AR01 BB17 CL10 KK12 KK26 2C087 AA03 AB05 AC08 BA02 BA03 BA07 BB10 BC07 2H034 FA01 5B057 AA11 CA01 CB01 CB08 CE08 CG07 5C076 AA14 BA06 5C077 LL14 MM27 MP08 NN07 NP07 PP20 PP23 PP33 PQ08 SS01 TT02 TT06

Claims (7)

[Claims] An input unit for inputting an image; an adding unit for adding forgery tracking information to the image; a forming unit for forming an image on a recording medium; and a forgery tracking information formed by the forming unit. An image processing apparatus, comprising: a control unit that causes the input unit to read the sample image obtained by the input unit and controls a condition for adding the forgery tracking information based on the read image. 2. The image processing apparatus according to claim 1, wherein the adding unit adds a dot pattern representing the forgery tracking information to an image. 3. The image processing apparatus according to claim 2, wherein the control unit controls a pixel value of the dot pattern based on a read image. 4. The image processing apparatus according to claim 2, wherein the control unit controls the size of the dot pattern based on the read image. 5. The image processing apparatus according to claim 2, wherein the control unit controls a pixel value and a size of the dot pattern based on the read image. 6. A control method for an image processing apparatus, comprising: an input unit for inputting an image; an adding unit for adding forgery tracking information to the image; and a forming unit for forming the image on a recording medium. Forming a sample image to which forgery tracking information is added, causing the input means to read the formed sample image, and controlling the addition condition of the forgery tracking information by the adding means based on the read image. How to control. 7. A recording device on which a program code for controlling an image processing apparatus having an input device for inputting an image, an adding device for adding forgery tracking information to the image, and a forming device for forming the image on a recording medium is recorded. A medium, wherein the program code comprises at least a code for causing the forming means to form a sample image to which the forgery tracking information is added; and a code for causing the input means to read the formed sample image. A code for controlling the addition condition of the forgery tracking information by the adding means based on the image.