JP2000165640A - Image processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit that can imbed additional data to a printed-out image in a way being visually unremarkable and also in a way that the additional data can be detected without failure from the read image data. SOLUTION: The image processing unit that superimposes additional data denoting additional information to image data is provided with an additional data imbed section 14. The additional data imbed section 14 uses a selector 145 that selects either of two kinds of patterns S0, S1. On the other hand, a maximum value calculation section 142 obtains a maximum value of the pixel values (densities) of an MCK component for each pixel of the input image data. Furthermore, a modulation quantity calculation section 143 calculates the modulation amount of the selected pattern, and multiplies the calculated modulation amount with each coefficient of the pattern selected by the selector 145 so as to change an amplitude of the pattern and to add it to the image data for imbedding the additional data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus for processing digital image data, and more particularly to a process for superimposing and embedding additional information in digital image data and detecting the embedded additional information. The present invention relates to an image processing apparatus that performs

[0002]

2. Description of the Related Art There is an additional data embedding technique for embedding additional information in digital image data in a superimposed manner. In recent years, the use of this additional data embedding technology for protecting the copyright of digital works such as still image data or preventing unauthorized copying has been active. There is also a movement to use the additional data embedding technology for the purpose of integrating specific electronic image data with another related digital image data or as confidential communication.

When the additional data embedding technique is used for the above purpose, additional data such as a copyright ID, a user ID, or arbitrary identification data is embedded in image data so as to be inconspicuous and distributed. Will be. As such an additional data embedding technique, for example, a technique of embedding additional data by superimposing a noise signal representing the additional data on image data (Japanese Patent Application Laid-Open No. Hei 9 (1990) -197).
Japanese Patent Application Laid-Open No. 10-1650), and a technique of embedding additional data by performing Fourier transform of image data and manipulating conversion coefficients of concentric regions indicating the same frequency in a frequency space. Are known.

[0004]

Since these additional data embedding technologies are used mainly for the purpose of preventing electronic illegal copying and unauthorized use of electronic image data, these additional image embedding techniques are not used for such electronic image data. The additional data is embedded in the image data so that the image quality does not deteriorate when the based image is displayed on the display device. for that reason,
Once the electronic image data is printed by the printer, it is difficult to read out the additional data embedded in the image data from the formed image on the paper after printing.

Therefore, even if the electronic image data has the additional data embedded therein, the additional data cannot be recognized from the printed out image. As a result, the copyright of the creator of the electronic image data is infringed. In order to be able to read the additional data from the printed image, it is conceivable that the embedding strength is increased and the additional data is embedded in the electronic image data to be distributed. There is a problem that image quality degradation when data is displayed on a display device also increases.

On the other hand, as a conventional technique for embedding additional data in an image after printout, a technique of embedding additional data in an image after print output by superimposing a pattern having positive and negative amplitudes with yellow ink on the image. (See JP-A-6-113107). However, according to this conventional technique, if all the bits are “0” as additional data to be embedded, the pattern is not embedded, so that the additional data is not embedded or all the bits are “0”. There is a problem that it is difficult to determine whether the additional data is embedded.

Further, as another conventional technique for embedding additional data in a printed image, two types of minute inclined patterns are formed by adding a code pattern corresponding to bits "0" or "1" of the additional data. There is a technology for detecting this code pattern from an image embedded and read by a scanner (see Japanese Patent Application Laid-Open No. 4-233677). However, in this prior art, since it is assumed that the code pattern is embedded in black in a white background area in the image, there is a problem that the embedded additional data becomes visible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a printed image in which additional data embedded in the image is read so as to be visually inconspicuous. It is an object of the present invention to provide an image processing apparatus capable of embedding additional data so that it can be reliably detected from data.

[0009]

An image processing apparatus according to the present invention comprises a density detecting means for detecting a density value of image data in a color component on which additional data representing additional information is superimposed;
If the density value detected by the density detecting means is less than a predetermined value, the density value of the image data is increased and additional data is superimposed. If the density value is more than the predetermined value, the density value of the image data is lowered and added. An additional data superimposing means for superimposing data is provided.

In the image processing apparatus having the above configuration, if the density value detected by the density detecting means is less than a predetermined value, the density of the printed image becomes relatively low, and the additional data becomes more conspicuous. The data superimposing means superimposes the additional data by increasing the density value of the image data. If the detected density value is equal to or higher than the predetermined value, the density of the image after printing out becomes relatively high, making it difficult to detect additional data. Therefore, the additional data superimposing means lowers the density value of the image data. To superimpose the additional data.

Another image processing apparatus according to the present invention comprises a density detecting means for detecting a density value of image data at a position where additional data representing additional information is superimposed, and a density value detected by the density detecting means being larger. And additional data superimposing means for superimposing the additional data by increasing the amplitude of the additional data to be superimposed.

In another image processing apparatus having the above structure, when the density value detected by the density detecting means is large, the density of the additional data embedding position in the printed image is relatively high, making the additional data less noticeable. Therefore, the additional data superimposing means increases the amplitude of the additional data to be superimposed. When the detected density value is small, the density of the additional data embedding position in the printed image becomes relatively low, and the additional data becomes more conspicuous. Reduce the volume.

[0013] Still another image processing apparatus according to the present invention includes:
Image data input means for inputting image data in which a pattern representing additional information is embedded, and an edge image for extracting an edge of a predetermined color component of the image data input from the input means and creating the edge image Creation means,
A pattern position determining means for obtaining a pattern position from at least one of the projection distributions in the main scanning direction and the sub-scanning direction of the edge image created by the edge image creating means; and a pattern position determined by the pattern position determining means. Pattern recognition means for performing recognition;
Additional data output means for outputting additional data according to the pattern recognized by the pattern recognition means is provided.

In still another image processing apparatus having the above-described configuration, when image data in which a pattern representing additional information is embedded is input from the image data input means, the edge image generating means determines a predetermined value of the image data. An edge image of the color component is created and supplied to the pattern position determining means. Then, the pattern position determining means obtains the position of the pattern from at least one of the projected distributions of the created edge image in the main scanning direction and the sub-scanning direction, and provides the pattern position to the pattern recognition means. In response,
The pattern recognition means performs pattern recognition at the pattern position. Then, the additional data output means outputs additional data according to the pattern.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to an embodiment of the present invention.

The image processing apparatus 10 according to the present embodiment includes an input / output unit 11 for inputting / outputting image data, an additional data detecting unit 12 for detecting additional data embedded in image data, an image data It has a memory 13 for storing data, an additional data embedding section 14 for embedding the additional data in the image data, an additional data deleting section 15 for deleting the additional data from the image data, and a control section 16 for controlling the entire apparatus. Are connected to each other via a bus line 17.

Here, the additional information represented by the additional data added to the image data may be any information. For example, address information on a network indicating a storage location of the image data, the image data or One example is ID information for identifying a copyright holder of an image.

FIG. 2 shows the configuration of the entire system using the image processing apparatus 10. The system includes a personal computer 21 connected to a network, and a display device 2 connected to the personal computer 21.
2, an image processing apparatus 10 to which image data is provided from a personal computer 21, a scanner 23 for reading a document and providing the image data to the personal computer 21 via the image processing apparatus 10, and an image processing apparatus 1
And a printer 24 for printing the image data output from the printer.

In the system having the above configuration, the user needs to receive image data via the network, store the image data in the personal computer 21, display the image data on the display device 22, and look at the displayed image. If there is, the image data is transmitted to the printer 24 via the image processing device 10 and printed on paper. At this time, the image processing apparatus 10 performs a process of embedding the additional data in the transmitted image data using an additional data embedding method suitable for printing by the printer 24.

Here, the additional data embedding method suitable for printing by the printer 24 is performed by converting each bit of the additional data into a pattern of minute inclined edges, and adding and superimposing the inclined edge pattern data on the image data. This is a method of embedding. When embedding this inclined edge pattern, embedding is performed only in the yellow component that is hardly noticeable visually, and by arranging each pattern roughly at intervals, it is possible to suppress deterioration of the image quality of the printed image, and When the data is read by the scanner 23, it is possible to easily detect the additional data.

Next, the operation of the image processing apparatus 10 and the specific configuration of the main part will be described. Image data transmitted from the personal computer 21 in FIG. 2 is input from the input / output unit 11 and stored in the memory 13. When the input of the image data is completed, the control unit 16 controls the additional data embedding unit 14 to perform the additional data embedding process.

FIG. 3 shows a first specific example of the configuration of the additional data embedding section 14. The additional data embedding unit 14 according to the first specific example includes a color conversion unit 141, a maximum value calculation unit 14
2, a configuration including a modulation amount calculation unit 143, a multiplication unit 144, and a selector 145. The additional data embedding unit 14 receives image data read from the memory 13 in block units.

In the additional data embedding section 14 having the above structure, the input RGB image data is
In step 1, the RGB color space is converted into a YMCK color space, which is the color space of the printer 24, and is output after being separated into a Y component and an MCK component. The image data of the MCK component is input to the maximum value calculation unit 142, and the maximum value calculation unit 142
In, the maximum value of the pixel value (density value) of each component is obtained for each pixel. The obtained maximum value is supplied to the modulation amount calculation unit 143.

The modulation amount calculation section 143 calculates the modulation amount of the pattern according to the maximum value of the MCK component at the embedding position of each pattern. The modulation amount calculator 143 modulates the pattern so that the larger the maximum value of the MCK component at the position where the pattern is embedded, the larger the modulation amount of the pattern, and the smaller the maximum value of the MCK component, the smaller the modulation amount of the pattern. An amount calculation process is performed.

The calculated amount of modulation is supplied to a multiplier 144. After the amount of modulation for one block is calculated, one additional data bit is read from the additional data storage area on the memory 13 and the selector 14 reads the additional data bit as select information.
5 given. When the additional data bit is provided, the selector 145 selects one of the two types of patterns S0 and S1 according to the bit information and supplies it to the multiplier 144.

The multiplication unit 144 multiplies each coefficient value of the pattern selected by the selector 145 by the modulation amount at the same pixel position obtained by the modulation amount calculation unit 143, and is further supplied from the color conversion unit 141. Is added to each pixel of the Y component image data at the same pixel position. As a result, the multiplying unit 144 performs processing such that the higher the density value of the MCK component, the larger the amplitude of the pattern, and the lower the density value of the MCK component, the smaller the amplitude of the pattern.

As described above, by superimposing the pattern (additional data) on the Y component image data with an amplitude corresponding to the density value of the MCK component, the MCK component in the image printed out by the printer 24 is obtained. Even if the density of the MCK component is high, it is possible to reliably detect the inclined edge pattern embedded in the Y component. Deterioration can be suppressed.

As described above, in the additional data embedding unit 14, the Y component image data in which the pattern (additional data) is embedded with an amplitude corresponding to the density value of the MCK component is output at the subsequent stage of the multiplier 144. It is combined with the MCK component image data. Then, the combined image data is output from the additional data embedding unit 14 and stored in the memory 13. The above processing is repeated for all blocks.

FIG. 4 shows an example of two types of patterns S0 and S1 used in the process of embedding additional data. 4A shows a pattern S0, and FIG. 4B shows a pattern S1. The size of the pattern is 16 × 16, which is the same as the size of the block of the image data. Compared with the size of the block, a portion having a plus or minus coefficient value that is arranged diagonally is made smaller. This is to make it visually inconspicuous. Further, in order to suppress yellowing of a white background or a low-density area of an image and to facilitate detection of an embedded pattern in a high-density area, a positive coefficient value b is set relatively small, and a negative coefficient The numerical value a is set relatively large.

FIG. 5 is an explanatory diagram of a pattern to be embedded in image data by the embedding process in the additional data embedding section 14. 5A shows image data before embedding a pattern, and FIG. 5B shows image data after embedding a pattern. If the density of the image data is low,
A relatively small edge is embedded in the Y component, and an edge having a large amplitude is embedded as the Y component density increases. Also, the amplitude of the edge increases as the density of the MCK component increases.

Thus, the embedding process of the pattern data (additional data) in the additional data embedding section 14 is completed. When the embedding process of the pattern data is completed, the control unit 16 reads out the embedded image data stored in the memory 13, outputs the image data from the input / output unit 11 to the printer 24, and prints on paper.

Next, the operation of the image processing apparatus 10 when an image printed on paper is read by the scanner 23 will be described. First, image data based on an image read by the scanner 23 is input from the input / output unit 11 and stored in the memory 13. When the storage of the image data in the memory 13 is completed, the control unit 16
Is controlled to perform additional data detection processing.

FIG. 6 shows an example of a specific configuration of the additional data detection unit 12. The additional data detection unit 12 includes a multiplexer (MUX) 121, a color conversion unit 122, a white pixel counting unit 123, and edge detection units 124m, 124c, and 12
4y, maximum value detection unit 125, inclined pattern emphasis unit 12
6, binarization processing section 127, pattern position determination section 128,
Coordinate value buffer 129 and pattern matching unit 13
0 is provided. Then, the image data stored in the memory 13 is input to the additional data detection unit 12.

In the additional data detecting section 12 having the above structure, the input image data is passed through a multiplexer 121 to a color converting section 122 and a white pixel counting section 123.
Is input to The image data input to the color conversion unit 122 is converted from the RGB color space into a YM
It is converted into a C color space, separated into a Y component and an MC component, and output.

Then, the Y component is supplied to an edge detecting section 124y, where an edge detecting filter process is performed. Thereafter, an oblique line pattern emphasizing section 126 performs an emphasis filter process for emphasizing an oblique line pattern, thereby performing an edge image Yedge.
Is generated and supplied to the binarization processing unit 127. on the other hand,
The image data of the MC component is input to two edge detectors 124
m and 124c, the edge detection filter processing is performed in parallel, and the maximum value detection unit 125 selects the larger one of the pixel values, thereby obtaining edge image data MC.
An edge is created and supplied to the binarization processing unit 127.

In the binarization processing section 127, two inputted edge image data Yedge and MCedge and two preset threshold values TH1 and TH2 are set.
Performs the following binarization processing. That is,
The edge image data Yedge is larger than the threshold value TH1 and the edge image data MCedge is
If smaller than H2, the pixel value "1" is output; otherwise, the pixel value "0" is output.

The binary image data created in this manner is oblique line pattern image data in which only the oblique edge of the Y component is extracted. The oblique line pattern image data is output from the additional data detection unit 12 and temporarily stored in the memory 13.
Is stored in In parallel with the above processing, the white pixel counting unit 123 determines whether each pixel value of the input image data is a white pixel by comparing each pixel value with a threshold value,
Control unit 1 counts the number of white pixels and counts the count value.
Output to 6.

Next, the oblique line pattern image data stored in the memory 13 is input to the additional data detection unit 12. The hatched pattern image data is supplied to the multiplexer 1
21 and input to the pattern position detection unit 128 via
The following pattern position calculation processing is performed.

First, the projection distribution Tx (i) in the main scanning direction and the projection distribution Ty (j) in the sub-scanning direction of the input binary diagonal pattern image data P (i, j) are obtained by the following equations. Tx (i) = Σj (P (i, j)) Ty (j) = Σi (P (i, j))

Thereafter, convolution projection distributions Ux (n) and Uy (m) are obtained by adding the obtained projection distribution at 16 intervals, which is the same pixel interval as the block size. Ux (n) = Σk (Tx (n + 16 * k)) n = 1, 2,... 16 Uy (m) = Σk (Ty (m + 16 * k)) n = 1, 2,.

The maximum values of the convolution projection distributions in the main scanning direction and the sub-scanning direction are the starting coordinates of the pattern position in the main scanning direction and the sub-scanning direction, respectively.
Positions separated by 6 pixel intervals are each pattern position coordinate. The obtained coordinate values are stored in the coordinate value buffer 129, output from the additional data detection unit 35, and stored in the coordinate storage area on the memory 13 at the same time.

Here, if the image data input from the scanner 23 is image data in which additional data is embedded, the obtained projection distribution is as shown in FIG.
The peaks and valleys have a periodic distribution that repeats at regular intervals, that is, at intervals of 16 pixels. The convolution distribution is shown in FIG.
As shown in (b), there is one mountain-shaped distribution, and the maximum value coincides with the pattern position. If the coordinates are used as a starting point and 16 are added in the main scanning direction and the sub-scanning direction, coordinate values of other patterns are obtained as shown in FIG. 7C.

Thereafter, the oblique line pattern image data stored in the memory 13 is input to the additional data detection unit 12. Then, for each of the obtained pattern position coordinates, the additional data detection process is performed by the pattern matching process in the pattern matching unit 130.

The pattern matching unit 130 reads out the pattern position coordinates from the coordinate value buffer 129, and stores one block of oblique line pattern image data (binary image image data) centered on the coordinates of the oblique line pattern image data stored in the memory 13. ) Read B. Then, for the read image data B for one block, matching values M0 and M1 of two patterns are calculated by the following equation. FIG. 8 shows patterns S0 and S1 to be used. In addition, AND of the following equation
Represents a logical product. M0 = Σij (AND (B (i, j), S0 (i, j)) M1 = Σij (AND (B (i, j), S1 (i, j))

The matching values M0 and M1 obtained by the above equation are compared with a preset threshold value TH3. If the matching value M0 is larger than the matching value M1 and the threshold value TH3, the value is added as an additional data bit. "0" is output, otherwise, "1" is output as additional data bits, and these are stored in the additional data storage area on the memory 34. The above pattern matching processing is performed for all pattern position coordinates, and the detection processing of the additional data is completed.

After the additional data detection process by the additional data detection unit 12 is completed, the control unit 16
Check the count value of the white pixel counted by 2;
If the number of white pixels is equal to or greater than a preset threshold, the image data input from the scanner 43
(Referred to as “scan-in image data”), there are many white background portions included in the image data. Therefore, when this image is displayed on the display device 22, it is determined that the yellow oblique line pattern existing in the white background background portion is easy to see. Deletion unit 1
5 is controlled to perform processing for deleting additional data, that is, oblique line edge patterns, from the scanned-in image data.

On the other hand, if the number of white pixels is less than the preset threshold value, the control unit 16 transmits the image data and the additional data stored in the memory 13 to the input / output unit 1.
1 to the personal computer 21.

FIG. 9 shows an example of a specific configuration of the additional data deleting section 15. The additional data deletion unit 15 includes the color conversion unit 1
51, smoothing unit 152, combining unit 153, selector 154
And a color conversion unit 155. Then, the additional data deletion unit 15 reads out the position coordinates of each pattern previously obtained from the coordinate storage area on the memory 13 and sets the coordinate values of the scanned-in image data stored in the memory 13 as the center. 1 block of image data to be read.

In the additional data deletion unit 15 having the above structure, the image data for one block read out is converted from the RGB color space into the YMC color space by the color conversion unit 151 and is separated into the Y component and the MC component. You. And Y
The components are directly supplied to the synthesizing unit 153, and are also subjected to smoothing filter processing in the smoothing processing unit 152 and are supplied to the synthesizing unit 153.

One of the patterns S0 and S1 selected by the selector 154 based on the additional data bits read from the memory 13 is input to the synthesizing unit 153. The synthesizing unit 153 replaces the pixels of the read image data of one block corresponding to the coefficients other than “0” in the pattern with the pixels of the image data that has been subjected to the smoothing filter processing, and outputs the result. FIG. 8A shows the pattern S0.
FIG. 2B shows the pattern S1.

After that, the color conversion section 155 performs the color conversion processing again to convert the image data into the original image data in the RGB space and output it. The output image data is stored in the memory 13. The above process is repeated for all blocks, and a process of deleting the oblique edge pattern from the scanned-in image data stored in the memory 13 is performed.

After the process of deleting the oblique line edge pattern is completed, the control unit 16 controls the image data and the additional data stored in the memory 13 to be transferred from the input / output unit 11 to the personal computer 21.

FIG. 10 shows a second specific example of the configuration of the additional data embedding section 14. The additional data embedding unit 14 ′ according to the second specific example has a color conversion unit 141, a maximum value calculation unit 142, a modulation amount calculation unit 143, a multiplication unit 144, a selector 145, and an average value calculation unit 146. The amplitude of the pattern is inverted according to the density of the pattern embedding position. Then, the image data read out from the memory 13 in block units is input to the additional data embedding unit 14 '.

In the additional data embedding section 14 'having the above structure, the input RGB image data is converted into the color conversion section 1'.
At 41, the RGB color space is converted into a YMCK color space, which is the color space of the printer 24, and is separated into a Y component and an MCK component and output. The image data of the MCK component is input to the maximum value calculation unit 142, and the maximum value calculation unit 14
In 2, the maximum value of the pixel value (density) of each component is obtained for each pixel. The obtained maximum value is supplied to the modulation amount calculation unit 143.

The modulation amount calculator 143 calculates the modulation amount of the pattern according to the maximum value of the MCK component at the embedding position of each pattern. The modulation amount calculator 143 modulates the pattern so that the larger the maximum value of the MCK component at the position where the pattern is embedded, the larger the modulation amount of the pattern, and the smaller the maximum value of the MCK component, the smaller the modulation amount of the pattern. An amount calculation process is performed.

The calculated amount of modulation is supplied to the multiplier 144. After the amount of modulation for one block is calculated, one additional data bit is read from the additional data storage area on the memory 13 and the selector 14 reads the additional data bit as select information.
5 given. When the additional data bit is provided, the selector 145 selects one of the two types of patterns S0 and S1 according to the bit information and supplies it to the multiplier 144.

On the other hand, the image data of the Y component is
4 and the average value calculation unit 146. In the average value calculation unit 146, the pixel value (density value) of the Y component image data
Is calculated for one block with respect to the maximum value of. The calculated average value is supplied to the multiplier 144.

The multiplying unit 144 first includes a modulation amount calculating unit 143
The amount of modulation at the same pixel position obtained by
A process of multiplying each coefficient value of the pattern selected by the above is performed. As a result, in the multiplying unit 144, the higher the density value of the MCK component, the larger the amplitude of the pattern becomes.
Processing is performed such that the lower the density value of the K component, the smaller the amplitude of the pattern.

The multiplier 144 further includes an average value calculator 14
According to the average value of the maximum value of the Y component of the block inputted from 6, the processing of adding / subtracting each coefficient value of the modulated pattern with respect to the pixel value of the image data of the Y component is performed.
Specifically, if the average value of the maximum value of the Y component is less than 128, for example, each coefficient value of the modulated pattern is added to the pixel value of the image data of the Y component and output, and the maximum value of the Y component is output. If the average value is 128 or more, each coefficient value of the modulated pattern is subtracted from the pixel value of the Y component image data and output.

Thus, in the multiplier 144, the density value of the image data in the Y component is set to a predetermined value (in this example, 12
8) If the value is less than the predetermined value, the density value of the Y component image data is increased to superimpose the pattern, and if the value is equal to or more than the predetermined value, the density value of the Y component image data is reduced to superimpose the pattern. Done.

As described above, the pattern (additional data) is superimposed on the image data of the Y component with an amplitude corresponding to the density value of the MCK component, and the average value of the maximum value of the Y component becomes a predetermined value. On the other hand, by controlling the density value of the Y component image data so as to be high when it is low and low when it is high, the printer 2
4, the inclined edge pattern can be reliably detected regardless of whether the density of the Y component is high or low.

As described above, in the additional data embedding section 14 ', the pattern (additional data) is embedded with the amplitude amount corresponding to the density value of the MCK component, and the average value of the density value is obtained with respect to a predetermined value. The image data of the Y component whose density value is controlled to be high when the value is low and low when the value is high is combined with the image data of the MCK component in a stage subsequent to the multiplier 144. Then, the combined image data is output from the additional data embedding unit 14 and stored in the memory 13. The above processing is repeated for all blocks.

FIG. 11 shows another example of the two types of patterns S0 and S1 used in the embedding process in the additional data embedding section 14 'having the above configuration. In FIG.
(A) is the pattern S0, and (b) is the pattern S1.
The patterns S0 and S1 according to the second specific example are also inclined patterns. However, unlike the patterns S0 and S1 according to the first specific example shown in FIG. 4, the patterns have an amplitude a only in the positive direction. I have.

FIG. 12 is an explanatory diagram of a pattern to be embedded in image data by the embedding process in the additional data embedding section 14 '. In FIG. 12, (a) shows the image data before the pattern is embedded, and (b) shows the image data after the pattern is embedded. When the density of the image data is low, the pattern of the amplitude in the positive direction is embedded in the Y component,
As the component concentration increases, the pattern of the amplitude in the negative direction is filled.

As described above, the additional data embedding section 14 '
The embedding process of the pattern data (additional data) is completed. When the pattern data embedding process is completed,
The control unit 16 reads out the embedded image data stored in the memory 13, outputs the image data from the input / output unit 11 to the printer 24, and performs printing on paper.

In the above-described embodiment, an example in which a diagonal edge pattern is used as a pattern has been described. However, the present invention is not limited to this example. Such other patterns, for example, a pattern formed by a set of dots arranged diagonally, a fine vertical line, a horizontal line pattern, or the like may be used. Further, as the information to be embedded, not only the information described in the above embodiment but also other arbitrary information may be embedded.

Further, in the above embodiment, the case where the detection and embedding processing of the additional data is performed by the independent image processing apparatus 10 has been described. However, the present invention is not limited to this, and the present invention is not limited to this. The processing may be performed by the software described above, or may be integrated into the printer.

[0068]

As described above, according to the present invention,
In an image processing apparatus for superimposing additional data representing additional information on image data, a density value of the image data in a color component on which the additional data is superimposed is detected, and when the density value is less than a predetermined value, the image data When the density value is increased and the additional data is superimposed, and when the density value is equal to or higher than the predetermined value, the density value of the image data is lowered and the additional data is superimposed. Even in the case, the additional data can be embedded so as not to be too conspicuous when it is thin, so that it is easy to detect.

In an image processing apparatus for superimposing additional data representing additional information on image data, a density value of image data at a position where the additional data representing additional information is superimposed is detected. By increasing the amplitude of the additional data to be superimposed and superimposing the additional data, it is possible to embed the additional data in the printed image so that it can be reliably detected regardless of whether the density is high or low. it can.

Further, in an image processing apparatus for detecting a pattern embedded as additional data representing additional information in image data, an edge image of a predetermined color component of the input image data is created, and a pattern of the pattern is formed from the edge image. The position is obtained, the pattern is recognized at the pattern position, and the additional data corresponding to the pattern is output, so that the additional data embedded in the image so as to be visually inconspicuous can be obtained from the read image data. It can be detected reliably.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an entire system using the image processing apparatus according to the embodiment.

FIG. 3 is a block diagram illustrating a first specific example of a configuration of an additional data embedding unit.

FIG. 4 is a diagram showing an example of two types of patterns S0 and S1 used at the time of additional data embedding processing according to a first specific example.

FIG. 5 is an explanatory diagram of a pattern to be embedded in image data in an additional data embedding process according to a first specific example.

FIG. 6 is a block diagram illustrating a specific configuration example of an additional data detection unit.

FIG. 7 is an explanatory diagram of a detection operation in an additional data detection unit.

FIG. 8 is a diagram showing an example of patterns S0 and S1 used for pattern matching.

FIG. 9 is a block diagram illustrating a specific configuration example of an additional data deletion unit.

FIG. 10 is a block diagram showing a second specific example of the configuration of the additional data embedding unit.

FIG. 11 is a diagram showing an example of two types of patterns S0 and S1 used in additional data embedding processing according to a second specific example.

FIG. 12 is an explanatory diagram of a pattern to be embedded in image data in additional data embedding processing according to a second specific example.

[Explanation of symbols]

10 image processing device, 12 additional data detection unit, 13
Memory, 14, 14 '... additional data embedding unit, 15 ...
Additional data deletion unit, 16 control unit, 21 personal computer, 22 display device, 23 scanner, 24 printer

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Claims (6)

[Claims] 1. A density detecting means for detecting a density value of image data in a color component on which additional data representing additional information is superimposed, and an image data when the density value detected by the density detecting means is less than a predetermined value. And an additional data superimposing means for superimposing the additional data by increasing the density value of the image data and superimposing the additional data by lowering the density value of the image data when the density value exceeds a predetermined value. 2. The image processing apparatus according to claim 1, wherein the predetermined value is an average value of density values of color components on which additional data is superimposed. 3. A density detecting means for detecting a density value of image data at a position where the additional data representing the additional information is superimposed, and an amplitude of the additional data to be superimposed as the density value detected by the density detecting means increases. And an additional data superimposing means for superimposing the additional data by increasing. 4. An image processing apparatus according to claim 3, wherein said density detecting means detects a density value of a color component other than a color component on which the additional data is superimposed. 5. An image data input unit for inputting image data in which a pattern representing additional information is embedded, and an edge of a predetermined color component of the image data input from the image data input unit is extracted. An edge image creating unit that creates an edge image; a pattern position determining unit that determines a position of the pattern from at least one projection distribution in a main scanning direction and a sub-scanning direction of the edge image created by the edge image creating unit; An image, comprising: pattern recognition means for performing pattern recognition at a pattern position determined by pattern position determination means; and additional data output means for outputting additional data according to the pattern recognized by the pattern recognition means. Processing equipment. 6. The image processing apparatus according to claim 5, wherein said predetermined color component is a yellow component.