JPH10243127A - Image processor and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cases where the added on additional information cannot be analyzed, by printing out 2nd image data with additional information added thereto by a 2nd additional means onto a 2nd side of a print medium different from a 1st side. SOLUTION: The size of each dot set in a 1st dot pattern is h1 in the main scanning direction and l1 in the sub scanning direction. A size of the 1st dot pattern is H1 in the main scanning direction and L1 in the sub scanning direction. On the other hand, a size of each doe set in a 2nd dot pattern is h2 (h2>h1) in the main scanning direction and l2 (l2>l1) in the sub scanning direction. A size of the 2nd dot pattern is H2 (H2>H1) in the main scanning direction and L2 (L2>L1) in the sub scanning direction. In this case, 2nd image data to which additional information is added by a 2nd additional means are outputted on a prescribed print means so as to be printed on a 2nd side of a print medium different from a 1st side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus and method for adding on predetermined additional information to color image data.

[0002]

2. Description of the Related Art In recent years, image processing apparatuses such as color printers and color copying machines have been able to form high-quality images by improving their performance. Under such circumstances, securities such as banknotes may be forged, and various forgery prevention techniques have been considered.

As one of the techniques, there is an add-on system in which a dot pattern indicating a machine number of an image processing apparatus is additionally printed together with a color image to be printed.

Since this dot pattern is periodically printed on the entire screen, additional information is added only to the yellow print surface.

[0005]

However, conventionally, only one of the various add-on methods described above is provided in the image processing apparatus, and the additional information is always added on by one method.

Therefore, for example, depending on the content of the printed image, the add-on method may not be suitable. In this case,
It becomes difficult to read the added-on color image and analyze the contents of the additional information.

The present invention has been made in view of the above conventional example, and has as its object to minimize the number of cases where additional information added on cannot be analyzed due to the contents of an image.

Another object of the present invention is to make it possible to analyze the added-on additional information in each of a plurality of apparatuses that analyze the additional information by different analysis methods when adding the additional information to the image.

It is a further object to add-on the above-mentioned additional information to an image so as to make it invisible to human eyes, so that the image itself can be used as an original image.

[0010]

According to the image processing apparatus of the present invention, the first image data is input, and the additional information is added to the first image data by the first additional data. First adding means for adding using a method, and outputting the first image data to which the additional information has been added by the first adding means to a predetermined printing means for printing on a first surface of a print medium. A first output unit, a second addition unit that inputs the second image data, and adds additional information to the second image data using a second addition method different from the first addition method; A second output unit for outputting the second image data, to which the additional information has been added by the second addition unit, to a predetermined printing unit so as to print the second image data on a second surface different from the first surface of the printing medium; It is characterized by having.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, a structure of an image recording apparatus using a color electrophotographic technique will be described. In this embodiment, the input density level is Y as an image signal.
(Yellow), M (magenta), C (cyan), BK
It is assumed that each color of (black) is sent in a frame-sequential manner.

FIG. 1 shows an example of the configuration of a color image processing apparatus for explaining an embodiment of the present invention. In the present embodiment, an operation in the duplex mode will be described.

An image signal generator (not shown) first outputs an image signal (YMC) indicating an image to be printed on the back side of the sheet.
K planes). When a semiconductor laser (not shown) is driven based on the transmitted image signal, the semiconductor laser emits laser beam light L. At this time, the charger 10
4, the photosensitive drum 105 is uniformly charged to a predetermined polarity, and the laser beam L
1, the photosensitive drum 1 via the lens 102 and the mirror 103
5, a yellow electrostatic latent image is formed on the photosensitive drum 105, for example.

Next, a required developing bias voltage is applied to a yellow developing unit Dy with respect to the image signal on the Y plane to develop a yellow latent image, and a yellow toner image is formed on the photosensitive drum 105. Is done.

The toner image formed on the photosensitive drum 105 is transferred to the transfer drum 106 as it is.

Next, a magenta latent image is similarly formed on the photosensitive drum 100 by the laser beam light L for the image signal of the M surface, and then the photosensitive drum 105 is formed by the magenta developing unit Dm. The upper magenta latent image is developed to form a magenta toner image.
06.

Subsequently, similarly, cyan and black toner images are transferred to the transfer drum 106, and as a result, a toner image in which four colors are superimposed is formed on the transfer drum 106.

On the other hand, at a predetermined timing,
The transfer paper P is fed from 07 and is guided to the transfer drum 105 via the paper feed roller 108, where the transfer of the toner image onto the paper P is performed. At the same time, the toner remaining on the transfer drum 106 is removed by the cleaner 106f to prepare for the latent image forming and developing steps on the surface of the sheet. On the other hand, the toner image on the back side of the sheet P is fixed by the fixing unit 109, and the image formation is completed.

Thereafter, the paper P is sent to the double-sided flapper 110, and the double-sided flapper 110
And drives the reversing roller 111 in the feeding direction.
When the sheet P is sent to the standby unit 112 in this manner, the reversing roller 111 starts a reversing operation. The sheet P advances to the duplex unit 113 by the reversing operation, and after the leading end of the sheet reaches a predetermined position, the conveyance is temporarily stopped and the lateral registration adjustment is performed. After the horizontal registration adjustment, the sheet is transported at a predetermined speed to the re-feed standby position. The above processing is controlled so that printing can be performed on the surface of the paper.

Next, a toner image on the front surface is formed on the transfer drum by the same method as that for the back surface, and the conveyance of the sheet subjected to the control for double-sided printing is resumed, and the transfer / fixing of the front surface is executed. Thereafter, the paper is discharged to the paper discharge unit 114 or 115. With the above printing operation, YM
A color image composed of CK can be formed.

Next, a dot pattern printed by the image processing apparatus of the present embodiment as additional information of an image will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 2, reference numeral 201 denotes a dot set, and each dot set includes a central density adding unit 301 and a density subtracting unit 302 on both sides as shown in FIG. Here, the density adding unit 301 adds a certain value to an actual image signal (in this case, a multi-valued image signal) to increase the density.
The density subtraction unit 302 subtracts the value from the image signal to lower the density.

The area 20 surrounded by the frame shown in FIG.
2 is one unit of the dot pattern, which is configured as a combination of a plurality of dot sets as can be seen from the figure. That is, the additional information can be represented by the positional relationship between a plurality of dot sets. By repeatedly printing this dot pattern on one surface of a sheet on which a color image is printed, additional information can be read from any area.

In the above-described dot pattern, conventionally, the size of a dot set (for example, 4 × 4 pixels) is commonly determined in advance. Therefore, even if a dot pattern is printed on both sides, the method of generating the dot pattern indicating the additional information is, of course, the same.

Hereinafter, a method of forming a dot pattern which is a feature of the present embodiment will be described with reference to FIG. In FIG. 4, the first dot pattern and the second dot pattern are dot patterns indicating the same additional information. In the first dot pattern, the size of each dot set is h1 in the main scanning direction and l1 in the sub-scanning direction. The size of the dot pattern is H1 in the main scanning direction and L1 in the sub-scanning direction.

On the other hand, in the second dot pattern, the size of each dot set is h2 (h2> h2) in the main scanning direction.
1), and l2 (l2> l1) in the sub-scanning direction.
Further, the size of the dot pattern is H2 (H
2> H1) and L2 (L2> L1) in the sub-scanning direction.

Further, the value obtained by dividing the total density value of all the dot sets in the first and second dot patterns added by the density adding section 301 by the area of each dot pattern becomes a certain value or less. So that That is, the average density addition value for each dot pattern should not be larger than the determined value. This is because the addition (density change) of the density by the density adding unit 301 is suppressed to a level that cannot be recognized by human eyes in both the first and second dot patterns. In particular, by making the average density addition value of the dot pattern unit the same for the first and second dot patterns, the first and second dot patterns cannot be recognized by the human eye at the same level.

Further, as described above, the size of the second dot pattern and each dot set thereof is larger than the size of the first dot pattern and each dot set thereof.

The first dot pattern is printed on the front side of the paper and the second dot pattern is printed on the back side of the paper. Note that this dot pattern is added on only for yellow (Y), which is a color that is difficult for human eyes to recognize, of the YMCK toner.

As described above, according to the present embodiment, the same information can be represented by using dot patterns of different sizes on the front and back sides of the sheet, so that either the first or second dot pattern can be used. As long as can be analyzed, a predetermined analyzer can recognize the additional information added to the color image. Therefore, the size of one type of added dot pattern is not compatible with the density and dither pattern of the color image formed by the image processing apparatus, so that the analysis apparatus cannot analyze the dot pattern. Thus, a dot pattern can be analyzed from another type of dot pattern.

As described above, since the same additional information is added on to the front and back sides of the sheet by using different methods, the additional information can be reliably analyzed.

An arrangement for printing the above dot pattern is shown below. Fig. 5
FIG. 3 is a block diagram of receiving the image signal of FIG. Hereinafter, yellow, magenta, cyan, and black are represented as Y, M, C, and BK.

In this embodiment, since the operation in the double-sided mode is described, an image signal on the back side is input first.
First, the color conversion processing unit 5 for the input image signal
01 is described. The color conversion processing unit 501 receives the R, G, and B image signals 515 and the color designation signal 514 on the back surface. The image processing device has Y, M, C,
Since each color of BK is printed one screen at a time, the image signals are image-sequential, that is, the image signal of one screen of Y, the image signal of one screen of M, the image signal of one screen of C, and the image signal of one screen of BK. In the order of the image signal. Therefore, the color conversion processing unit 501 uses R
First, an image signal for one screen of GB is converted into an 8-bit image signal of a Y (yellow) image signal for each pixel. Next, the M image signal, the C image signal, and the BK image signal are converted in this order. At the time of this conversion, masking and UCR processing are added. In the color conversion processing unit 501, the input RG
The color designation signal 514 sent from the above-described image signal generation means indicates which color of the Y, M, C, and BK signals are to be converted and output. That is, the color designation signal 514 is switched in the order of M, C, and BK each time the color processing unit 501 receives the image signal for one screen by designating Y, and sequentially converts the RGB signals into Y, M, C, and BK. Are converted into respective image signals.

Reference numeral 502 denotes a density correction unit, which includes Y, M, C, and BK.
Each 8-bit image signal is received and a correction is made according to the output characteristics of the printing unit. The signal converted by the density correction unit is input to a dot pattern addition unit 503. R
The OM 504 stores a code in which additional information such as a model number and a machine number of the image processing apparatus of the present invention is encrypted, and generates a first dot pattern generation circuit 505 and a second dot pattern generation circuit 517 as a code signal 517. Circuit 506
Is input to Here, the first dot pattern generating circuit 505 generates the above-described first dot pattern indicating the additional information, and the second dot pattern generating circuit 506 generates the second dot pattern indicating the same additional information as the above-described additional information. A dot pattern is generated. Each dot pattern generation circuit (5
05, 506), dot pattern data (values to be added or subtracted) 518, 519 indicating the code signal 517 (ie, additional information) are input to the selector 507.
First, the selector 507 selects the data 518 from the first dot pattern generation circuit and inputs the data 518 to the adder 503 because the first printing is processing on the back side. The adder 503 adds dot pattern data to the input image signal only when the color designation signal 514 designates Y, and outputs M, C, and BK.
Is not added.

The image signal of each color subjected to the above processing is input to a PWM (Pulse Width Modulation) unit 508. PWM
The unit 508 synchronizes the 8-bit image signal with the rising edge of the image clock PCLK 516 by the latch circuit 509,
The signal is converted into an analog voltage by the / A converter 510 and input to the analog comparator 511. On the other hand, a triangular wave is generated by a triangular wave generator 513 by the image clock 516 and is input to the analog comparator 511. The analog comparator 511 outputs the analog voltage and the triangular wave.
The signals are compared, a PWM signal is output, inverted by an inverter 512, and a PWM signal is obtained. The PWM signal is input to the laser driver and printed.

After the printing on the back side is completed, an image signal on the front side is input and the same processing as described above is performed. For the front side, the selector 507 sends the tracking signal 519 from the second dot pattern generation circuit to the front side. Select and input to addition section 503. Subsequent printing processing is performed in the same manner as for the back surface, and the second dot pattern is added to the Y image on the front surface. As a result, a dot pattern and a dot pattern having a different dot set size are printed on the front surface and the back surface.

(Second Embodiment) Next, another embodiment for realizing the present invention will be described. In this embodiment, the pattern added to the front surface is referred to as pattern A, and the pattern added to the back surface is referred to as pattern B. FIG. 6 shows an arrangement example of the pattern A.
Reference numeral 601 denotes one unit of the dot pattern of the pattern A. A plurality of reference circles 602 exist in the dot pattern, and a line 603 indicating the 0-degree direction of each reference circle is set as a reference line. A reference dot 604 of each circle is formed at a position where the reference line 603 and each circle intersect. Next, 0-18 on each base circle
The area of 0 degrees, that is, the area above the reference line 603 in the figure is defined as area A, and the area of 180 to 360 degrees on the reference circle, that is, the area below the reference line 603 in the figure is area B.
Then, one dot is formed on each of the areas A and B of each reference circle. Areas A and B are each divided into 16 based on the angle with respect to the circle, and the position (angle) of the dot, that is, the angle between the dot and the reference dot, represents the code of the reference circle. In the case of FIG. 6, since there are seven reference circles, 14 codes including areas A and B can be embedded therein. Since each code can represent 4 bits (16) of information, a total of 56 bits of information can be represented. The model code, machine code, etc. are put in these. The above pattern is repeatedly generated in the image.

Next, the pattern B will be described. Reference numeral 701 denotes one unit of the pattern B dot pattern. Reference numeral 702 denotes a reference line of the pattern B. Four dots are placed on each reference line, and distances 703 to 706 between the dots represent codes of the reference line. Note that 706 represents the distance from the leftmost dot of the adjacent dot pattern. Since the distance between dots can represent any of the predetermined lengths of 0 to 15, one dot can represent 4-bit information. Therefore, each reference line can represent 4 × 4 bits of 16 bits of information. In the case of the figure, since there are eight reference lines, the entire pattern B can represent 128 bits of information. The above pattern is repeatedly generated in the image.

If the image processing apparatus can generate the two patterns as described above, the dot pattern of the pattern B is added to the yellow surface image when the image on the back surface is first printed as in the first embodiment. The next time the front side image is printed, the pattern A is added to the yellow side image.
By adding on the dot pattern described above, different types of dot patterns can be inserted on the front and back sides of the sheet. Also in the present embodiment, by controlling the average addition density in each pattern area of the pattern A and the pattern B, the image density change due to the addition of the dot pattern can be made inconspicuous to the user on both the front surface and the back surface. .

In this embodiment, the pattern A
And the amount of additional information that can be expressed by the pattern B is different, and further information may be inserted for the pattern B having a large allowable amount by using this.

Also in the present embodiment, by adding on the same information by a different method, even if the additional information added by one method cannot be analyzed, the additional information is added by the other method. Since the additional information can be analyzed, the possibility of analyzing the additional information increases.

According to the first and second embodiments, the additional information can be added on by a plurality of different methods, so that it is possible to simultaneously support a plurality of types of devices for analyzing the add-on information. . In that case, additional information corresponding to each of these plural types of devices may be added on to each pattern, and it is not particularly necessary to add on the same additional information.

Note that the present invention is not limited to the above-described embodiment, and the same effects as those of the present invention can be obtained as long as the image processing apparatus has a plurality of types of add-on methods for adding on the additional information so that the additional information is hardly visible to human eyes. Can be obtained.

It is needless to say that the present invention includes a method for performing the processing of the image processing apparatus described above. A storage medium storing a program is also included.

[0044]

As described above, according to the present invention, the first
In the second embodiment, the size of the dot pattern added on the front and back surfaces of the paper is made different, and in the second embodiment, the method of adding the dot pattern on the front surface and the back surface of the paper itself is made different. It is possible to minimize the case where the additional information added cannot be analyzed due to the content of the image. Further, according to such a configuration, it is possible to analyze the additional information added by each of the plurality of devices that analyze the additional information by different analysis methods.

Further, the add-on of the additional information to the color image is performed on the yellow surface of the color image so that the additional information becomes less visible to human eyes, and the color image itself can be used as an original image.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a printing unit of a color image recording apparatus according to first and second embodiments of the present invention.

FIG. 2 is a diagram illustrating a dot pattern according to first and second embodiments of the present invention.

FIG. 3 is a diagram illustrating a principle of a dot set of a dot pattern according to the first and second embodiments of the present invention.

FIG. 4 is a diagram showing first and second dot patterns according to the first embodiment of the present invention.

FIG. 5 is a block diagram of a multi-level processing unit according to the first and second embodiments of the present invention.

FIG. 6 is a diagram illustrating a dot pattern A according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a dot pattern B according to a second embodiment of the present invention.

[Explanation of symbols]

 104 Charger 105 Photosensitive Drum 106 Transfer Drum 106f Cleaner 503 Tracking Pattern Addition Unit 505 First Tracking Pattern Generation Circuit 506 Second Tracking Pattern Generation Circuit 508 PWM Unit

Claims (11)

[Claims] A first adding unit that inputs first image data and adds additional information to the first image data by using a first adding method; A first output unit for outputting the first image data to which the first image data is added to a predetermined printing unit so as to print the first image data on a first surface of a print medium; and a second image data. A second adding unit for adding the additional information using a second adding method different from the first adding method, and printing the second image data to which the additional information is added by the second adding unit. An image processing apparatus comprising: a second output unit that outputs to a predetermined printing unit to print on a second surface different from the first surface of the medium. 2. The image forming apparatus according to claim 1, wherein the first adding unit adds the first dot pattern including the plurality of dots to the first image data, using the additional information as information including a combination of a plurality of dots. The image processing apparatus according to claim 1, wherein: 3. The image forming apparatus according to claim 2, wherein the second adding unit adds the second information as the information comprising a combination of a plurality of dots, and adds a second dot pattern including the plurality of dots to the second image data. The image processing apparatus according to claim 1, wherein: 4. The method according to claim 1, wherein the first adding unit adds the first dot pattern including the plurality of dots to the first image data, using the additional information as information including a combination of a plurality of dots. The second adding unit sets the additional information as information comprising a combination of a plurality of dots and converts a second dot pattern including the plurality of dots into the second dot pattern.
2. The image processing apparatus according to claim 1, wherein a size of the first dot pattern area and a size of the second dot pattern area are different from each other. 3. 5. The first adding unit adds the first dot pattern including the plurality of dots to the first image data as the additional information as information including a combination of a plurality of dots. The second adding unit sets the additional information as information comprising a combination of a plurality of dots and converts a second dot pattern including the plurality of dots into the second dot pattern.
2. The size of each dot forming the first dot pattern and the size of each dot forming the second dot pattern are different from each other when added to the image data.
An image processing apparatus according to claim 1. 6. The apparatus according to claim 1, wherein the additional information added by the first adding unit and the additional information added by the second adding unit are the same information. Image processing device. 7. The apparatus according to claim 1, wherein the additional information added by the first adding unit and the additional information added by the second adding unit include the same information. The image processing apparatus according to any one of the preceding claims. 8. The image processing apparatus according to claim 1, wherein the first image data and the second image data are color image data including a plurality of color components. 9. The method according to claim 1, wherein the addition of the additional information by the first or second adding means is performed only for one part of a plurality of components constituting the color image data. Item 9. The image processing device according to item 8. 10. The image processing apparatus according to claim 1, further comprising the predetermined printing unit. 11. A first adding step in which first image data is input and additional information is added to the first image data by using a first adding method, and the additional information is added in the first adding step. A first output step of outputting the first image data to which the first image data is added to a predetermined printing means so as to print the first image data on a first surface of a print medium; and inputting second image data. A second adding step of adding the additional information using a second adding method different from the first adding method, and printing the second image data to which the additional information has been added in the second adding step. A second output step of outputting to a predetermined printing means to print on a second surface different from the first surface of the medium.