JP3265472B2 - Apparatus and method for detecting information embedded in an image, and recording medium recording computer program for detecting information embedded in an image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a recording medium recording a computer program for detecting system and information embedded in the method及beauty picture image in which to detect the information embedded in the images More particularly, the present invention relates to a technique for printing an image such as a picture on paper and embedding other information such as character information in the image.

[0002]

2. Description of the Related Art Conventionally, as a method of transmitting information, necessary information has been written on paper and passed to a person who wants to transmit the information, thereby transmitting the necessary information. However, when such a method is used, there is a problem that the information content is easily leaked to others.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of the prior art, and in particular to make it possible to conceal information even when transmitting information using a medium such as paper. A new information record carrier is provided. Or,
Another object of the invention is to provide a method for embedding information in an image for creating said information record carrier.
Another object of the present invention is to provide an apparatus and a method for detecting information embedded in the information record carrier.

[0004]

Since the present invention SUMMARY OF] is to achieve the above object, basically, Ru der should be adopted technical construction as described below.

[0005]

Another aspect of the apparatus for detecting information embedded in an image according to the present invention is to allocate a square or rectangular area in an image printed on a record carrier, and
Is divided into multiple parts vertically and horizontally, and a plurality of partitioned pixels
And at least two or more of the pixels have a first
The first bit data is drawn by filling in the direction
Record "0" and at least two or more of this pixel
The second bit is drawn by filling in the second direction
A device for embedding information in which data "1" is recorded and detecting the information, wherein the square or rectangular area is allocated on a record carrier, and this area is divided into three or more in each of the vertical and horizontal directions to form at least 9 A first unit for extracting the pixels partitioned as described above, and a pixel assigned by the first unit.
A first area having a predetermined square or rectangular shape, and bit data of the first area , which are continuously arranged in the first area.
And the first area in which the same bit data is embedded.
A plurality of positives consisting of the same square or rectangular second area
A rectangular or rectangular area is cut out and the first area and the
Second means for blocking an area consisting of the first and second areas, third means for detecting the brightness of each pixel constituting the area blocked by the second means, and the first means .
Based on the brightness of each pixel obtained in said third means an area as a unit, Me calculated moving average value in each moving average can be calculated pixel, resulting moving average the pixel
The fourth means for lightness, the differences between the detected brightness signal with a third said the detected brightness data unit of the fourth means calculates for each pixel, the embedded bit pattern A fifth means for obtaining data for detection;
Using the detection data obtained by the means of ( 1), the first
Said pixels corresponding to pixels consecutive in the direction or in the second direction.
Based on the cumulative value of the product of the detection data,
At least two pics in a square or rectangular area
Cells are filled so as to line up in the first direction
Or is painted so as to line up in the second direction
Determining whether the bit pattern embedded in each area is “0” or “1”,
It is characterized by comprising.

[0007] Another aspect of the method for detecting information embedded in an image according to the present invention is to allocate a square or rectangular area in the image printed on the record carrier.
Is divided into multiple parts vertically and horizontally, and a plurality of partitioned pixels
And at least two or more of the pixels have a first
The first bit data is drawn by filling in the direction
Record "0" and at least two or more of this pixel
The second bit is drawn by filling in the second direction
A method for embedding information in which data “1” is recorded and detecting the information, wherein the square or rectangular area is allocated on a record carrier, and this area is divided into three or more in each of vertical and horizontal directions, and at least 9 a first step of extracting a section pixel above, allocated in the first step
A first area having a predetermined square or rectangular shape, and bit data of the first area , which are continuously arranged in the first area.
And the first area in which the same bit data is embedded.
A plurality of positives consisting of the same square or rectangular second area
A rectangular or rectangular area is cut out and the first area and the
A second step of blocking a region consisting beauty second region, a third step of detecting the brightness of each pixel constituting the blocked areas in the second step, the first
Based on the brightness of each pixel obtained in the third step the area as a unit, Me calculated moving average value in each moving average can be calculated pixel, resulting moving average the pixel
Of a fourth step of the brightness, the third difference and calculates for each pixel the detected brightness signal and the fourth in the process of the detected brightness signal in step, the embedded bit pattern of A fifth step of obtaining data for detection;
Using the detection data obtained in the step of
Said pixels corresponding to pixels consecutive in the direction or in the second direction.
Based on the cumulative value of the product of the detection data,
At least two pics in a square or rectangular area
Cells are filled so as to line up in the first direction
Or is painted so as to line up in the second direction
A sixth step of determining whether the bit pattern embedded in each area is “0” or “1” by determining
It is characterized by including.

[0008] Another aspect of the recording medium according to the present invention is that a square or rectangular area is included in an image printed on a record carrier.
, And divide this area into multiple parts vertically and horizontally,
Form a partitioned pixel of
Fill two or more lines in the first direction
Records the first bit data "0" at
Fill so that at least two or more are lined up in the second direction
This is a recording medium in which information recording the second bit data “1” is embedded, and on which a computer program for detecting the information is recorded, wherein the square or rectangular shape is recorded on a record carrier. A first procedure of allocating an area, dividing the area into three or more in each of the vertical and horizontal directions, and extracting pixels divided into at least nine or more, and dividing the area by the first procedure.
A first area of a predetermined square or rectangle applied thereto;
The first region is disposed continuously to the first region, and the first region
Wherein the same bit data and bit data are embedded
From the first area and the same square or rectangular second area
Made by cutting a plurality of square or rectangular area, the
A second procedure for blocking an area consisting of the first area and the second area, and a third procedure for detecting the brightness of each pixel constituting the area blocked in the second procedure . procedure and, wherein the first region as a unit based on the third brightness of each pixel obtained by the procedure of seeking Me a moving average of the moving average can be calculated for <br/> each pixel, obtained Moving average
A fourth step in the brightness of the pixels, the difference between the detected brightness signal with a third said the detected brightness signal with the procedure of the fourth step calculates for each pixel, embedded Fifth procedure for obtaining bit pattern detection data, and pixels continuous in the first direction or the second direction using the detection data obtained in the fifth procedure.
Based on the cumulative value of the product of the detection data corresponding to
At least within the square or rectangular area cut out
Fill so that two or more pixels are aligned in the first direction
Crushed or painted so as to line up in the second direction
A sixth procedure for determining whether the bit pattern embedded in each area is “0” or “1” by determining whether the bit pattern has been erased, and a computer readable recording program for executing the sixth procedure. Recording medium.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The information record carrier according to the present invention allocates a square or rectangular area on an image printed on the record carrier, and divides this area into three or more in each of vertical and horizontal directions.
A first bit is recorded by forming at least nine or more partitioned pixels, filling at least two or more of the pixels in a first direction, and recording at least two or more of the pixels in a second direction. Since the second bit is recorded by painting in such a way that the colors are lined up in the direction, an image such as a picture on paper can be recognized, but information embedded in this image is Not recognizable by human eyes. Moreover, since it is not possible to recognize that information is embedded, it is possible to conceal information in a natural state.

[0010]

To BRIEF DESCRIPTION apparatus for detecting information embedded in image in image that involved in the present invention and a specific example of how in detail with reference to the drawings. FIG. 1 is a diagram showing a method of embedding information in an image according to the present invention and a specific example of an information recording medium. In these figures, a square or a rectangle is shown on an image 2 printed on a record carrier 1. Area 3 is divided, and the area 3 is divided into three or more in each of the vertical and horizontal directions, and at least 9
The above partitioned pixel 4 is formed, and this pixel 4
The first bit “0” is recorded by filling at least two or more of the pixels 4a, 4a, 4a, and 4a so as to be arranged in the first direction 5a, and at least two or more of the pixels 4 4b, 4b, 4b, The image 2 in which the second bit “1” is recorded by painting 4b so as to line up in the second direction 5b
A method of embedding information in an image, wherein the first direction 5a and the second direction 5b form an angle of about 90 degrees.
The first direction 5a and the second direction 5b are diagonal directions 7a and 7b of the square or rectangular region 3, respectively.
A method of embedding information in an image is shown, wherein a plurality of the square or rectangular areas 3 are arranged, and each of the plurality of areas 3 has the same bit. A method of embedding information in an image in which the brightness of the image 2 in the square or rectangular area 3 is recorded by filling at least two or more of the pixels is shown. In addition, it is shown that the brightness records at least three levels of brightness.

Further, a square or rectangular area 3 is allocated on the image 2 printed on the record carrier 1, and this area 3 is divided into three or more in each of the vertical and horizontal directions, and at least nine or more partitioned pixels 4 are formed. The first bit “0” is recorded by forming and filling at least two or more of the pixels 4 4a, 4a, 4a, and 4a so as to be aligned in the first direction 5a, and recording at least two or more of the pixels 4 4b, 4b,
4b, 4b are painted so as to be arranged in the second direction 5b to indicate an information record carrier that records the second bit “1”. The first direction 5a and the second direction 5b are: An information record carrier characterized by being substantially 90 degrees is shown, and the first direction 5a and the second direction 5b are
Diagonal direction 7 of the square or rectangular area 3 respectively
a, 7b, wherein a plurality of the square or rectangular areas 3 are arranged, and each of the plurality of areas 3 has the same bit. An information record carrier that records the brightness of the image 2 in the square or rectangular area 3 by filling at least two or more of the pixels is shown, and the brightness is at least An information record carrier recording three or more levels of brightness is shown.

Next, the present invention will be described in more detail. The present invention, for example, is to confidentially record data such as text in a picture drawn on paper, so that one area shows data bits and furthermore, an image in that area is displayed. By expressing the brightness, data such as text is recorded in the image. For this reason, a pattern in which the bits of the area are identifiable as 0 or 1 is prepared in advance, and a pattern indicating the brightness of the image of the area to which each pattern is assigned is prepared. FIG. 4A shows a pattern indicating a bit “0”. In this specific example, the inside of the square area 3 is equally divided into 16 equal parts, and
Six pixels 4 are formed, and the pixels 3 are painted two by two so that the brightness of the region 3 is expressed in seven levels of brightness. Then, the filling direction is set to the diagonal line 7a so that all the patterns in FIG. 4A represent all the bits “0”. Similarly, FIG.
Is a pattern indicating a bit “1”. In this specific example, at least two pixels 4 are filled, so that the brightness of the image of the area 3 is expressed in seven levels of brightness. Then, the filling direction is set to the diagonal line 7b so that all the patterns in FIG. 4B represent the same bit “1”. Then, in order to facilitate detection, a plurality of, for example, four areas 3 are arranged so that each of the plurality of areas 3 records the same bit. FIG. 3 shows a specific example.
In each of the three areas 3, a bit "1" is recorded, and a recording pattern in which the brightness of the picture, that is, the brightness decreases from the upper left to the lower right is shown.

Next, the procedure of embedding the pattern thus configured will be described. First, the square or rectangular area 3 is arranged on the image 2 to be embedded, and the brightness data of 16 partitioned pixels 4 is obtained.
Methods for obtaining brightness data include R (red), G (green),
G (green) data among the three primary color data of B (blue) is preferably used as brightness data. Then, as shown in FIG. 5, after detecting the data of each pixel 4, all of them are averaged to make the brightness of the region 3. In the case of FIG. 5, the average value of the brightness of the area 3 shown in this figure is 175. Then, the data is converted into a predetermined brightness. In the case of FIG. 5, this value 175 corresponds to the brightness of the average value 160 to 219 from FIG. If the bit "1" is to be recorded in this area, the corresponding pattern P in FIG. 4B is selected, and this pattern is recorded. As described above, four bits “1” are arranged in order to facilitate detection. As described above, a pattern P corresponding to the brightness of each area is selected, and the pattern P is arranged at a pre-allocated location. I do. By performing this process four times, for example,
One bit as shown in FIG. 3 can be recorded. FIG. 6 is a flowchart of an apparatus for embedding information in an image. As described above, the square or rectangular area 3 is divided into three or more in each of the vertical and horizontal directions to form at least nine or more partitioned pixels 4. After arranging this area at a predetermined place (step S1), the brightness of each pixel 4 of the square or rectangular area 3 is extracted (step S2),
After averaging the brightness of the extracted area 3 (step S3), the averaged brightness is converted into a predetermined brightness (step S4).

Next, in order to record the first bit or the second bit, after selecting a pattern corresponding to the brightness from a predetermined pattern (step S5), the selected pattern is converted into the square or rectangle. Recording is performed in the arranged area 3 (step S6). FIG. 7 is a functional block diagram of a device for embedding information in an image. The device for embedding information in an image according to the present invention divides the square or rectangular area 3 into three or more in each of vertical and horizontal directions. Means 11 for forming at least 9 or more partitioned pixels 4 and arranging this area 3 in a predetermined place; means 12 for extracting the brightness of each pixel 4 of said square or rectangular area 3; Means 13 for averaging the brightness of the area, and means 14 for converting the averaged brightness to a predetermined brightness
Means for selecting a pattern corresponding to the brightness from a predetermined pattern to record the first bit or the second bit, and recording the selected pattern in an area where the squares or rectangles are arranged And means 16 for performing the operations.

Next, a method of detecting a bit pattern according to the present invention will be described. When detecting a bit pattern according to the present invention, as shown in FIG. 8, a case where a black image from the upper left to the lower right as if a bit pattern "0" is overlapped with an area indicating a bit pattern "1" There is. In such a case, a pattern from the upper left to the lower right is detected, and an erroneous detection of detecting the bit pattern of this area as “0” despite the bit pattern “1” is avoided. Therefore, it is necessary to remove the influence of the black pattern from the upper left to the lower right. Because of this,
In order to eliminate the influence of the image while leaving the image of the bit pattern, the brightness of each pixel is moving averaged, and the moving averaged data is subtracted from the original data to remove the effect of the image at the time of reading. , Enabling accurate bit pattern detection.

As a specific method, as shown in FIG. 9, the average value of the pixels A, B, and C is set to the brightness of the pixel B, and similarly, the average value of the pixels B, C, and D is set to the brightness of the pixel C. The brightness of the pixels is used, and the brightness of the pixels A and D is used as it is as the brightness of the pixels A and D. Such processing is performed on other pixels to obtain the data of FIG. 9B. Next, by subtracting the moving averaged brightness data of FIG. 9B from the original brightness data of FIG. 9A, FIG.
Get the data conversion. Next, the bit data shown in FIG. 9C is detected. In this case, it is only necessary to detect the direction of the filled pixel. Specifically, as shown in FIG. 10, the brightness data of each pixel is
First, B * E + C * F + F * I + D * G + G * J + J *
M + H * K + K * N + L * O ... Calculate the value of (1),
Next, C * H + B * G + G * L + A * F + F * K + K *
By calculating the value of (P + E * J + J * O + I * N) (2), it is possible to identify whether the direction of the black-painted pattern is lower left or lower right. Then, it is determined whether the bit pattern is “0” or “1”. In the case of FIG. 10, the value of equation (1) is 8951
6, and the value of Expression (2) is 13207, so that the bit data in this area is determined to be “1”.

FIG. 11 is a flow chart for detecting information according to the present invention. A square or rectangular area is allocated on a record carrier, and this area is divided into three or more in each of the vertical and horizontal directions, and at least nine or more sections are defined. After the formed pixels are formed (step S11), the square or rectangular area in which the same data is recorded is cut out and formed into blocks (step S12).

Next, after detecting the brightness of each pixel in the square or the rectangle (step S13), in order to eliminate the feature of the image in each of the cut out and blocked regions, each of the square or the rectangle is removed. The brightness of each pixel is averaged (step S14), and the difference between the brightness data of step S13 and the brightness data obtained in step S14 is calculated to obtain detection data (step S15). Finally, it is determined whether the bit pattern of each of the square or rectangular regions obtained in step S15 is "0" or "1" (step S16). The bit pattern detected as described above may be guided to a predetermined device and converted into, for example, voice, or may be printed and output on a printer. Therefore, the information embedded in the image may be character data, audio information, or image information.

FIG. 12 is a functional block diagram of a device for detecting information embedded in an image. The device for detecting information embedded in an image according to the present invention is a square or a square on a record carrier. Means 21 for allocating a rectangular area and dividing the area into three or more in each of the vertical and horizontal directions to form at least nine or more partitioned pixels, and a plurality of the square or rectangular areas in which the same data is recorded A means 22 for cutting out and blocking, then a means 23 for detecting the brightness of each pixel in the square or rectangle, respectively, and the square or the block for eliminating the feature of the image in each of the cut and blocked areas. Means 24 for averaging the brightness of each pixel of the rectangle, and a difference between the brightness data obtained by the means 23 and the brightness data obtained by the means 24, respectively, to calculate the detection data. A means 25 for obtaining the data, the bit pattern of the detection data is constituted by the identifying means 26 which calculates the whether it is "0", "1". Note that the above-described means may be configured by hardware or software. In addition, a recording medium that records a computer program for detecting information embedded in an image according to the present invention allocates a square or rectangular area on a record carrier, and divides this area vertically and horizontally by three times.
A first step of extracting at least 9 or more partitioned pixels by dividing the area into a plurality of areas, and extracting a plurality of areas continuously arranged in the area and embedding the same bit data; A second step of blocking these regions, a third step of detecting the brightness of each pixel constituting each of the regions, and a process for each pixel based on the brightness of each pixel obtained in the third step. A fourth step of obtaining a moving average of the pixel values and replacing the brightness of each pixel with the obtained moving average, and a difference between the brightness data detected in the third step and the brightness data detected in the fourth step. And calculating the embedded data in each of the regions by using the detection data obtained in the fifth step. The one run and the sixth step of identifying a bit pattern is "0" at which either "1"
Computer with recorded program
It is a possible recording medium.

Further, in the above example, when the bit patterns are put in the square or rectangular area 3, the bit patterns are arranged in a direction parallel to the diagonal line. However, the bit patterns may be arranged so as to be parallel to each side. . Also, the area 3 is 16 in the above example.
Although the configuration is made such that the pixel is divided into 9, or 25 or more pixels. Further, in the above description, the brightness level is set to 7
The number of stages is set, but three or more stages are sufficient.
In the above description, a moving average is taken to make it easier to detect the bit pattern. However, any method may be used as long as the influence of the image can be eliminated.

[0021]

Effect of the Invention The present onset Ming, since it is configured as above described,
Although an image such as a picture on paper can be recognized, information embedded in the image cannot be recognized by human eyes. Moreover, since it is not possible to recognize that information is embedded, it is possible to conceal information in a natural state.

[Brief description of the drawings]

FIG. 1 is a diagram showing one specific example of an information recording carrier according to the present invention.

FIG. 2 is a diagram showing a configuration of a bit pattern.

FIG. 3 is a diagram showing a bit pattern on an image.

FIG. 4 is a diagram showing a pattern in which bit patterns “0” and “1” are made to correspond to respective lightness levels.

FIG. 5 is a diagram showing a state in which a bit pattern is selected from the average brightness of each area.

FIG. 6 is a flowchart illustrating an operation of the apparatus for embedding information in an image according to the present invention.

FIG. 7 is a functional block diagram of an apparatus for embedding information in an image according to the present invention.

FIG. 8 is a diagram for explaining the detection of a bit pattern by the device for detecting information embedded in an image according to the present invention.

FIG. 9 is a diagram for explaining processing for eliminating the influence of an image when detecting a bit pattern.

FIG. 10 is a diagram for explaining a method for detecting a bit pattern.

FIG. 11 is a flowchart illustrating an operation of the apparatus for detecting information embedded in an image according to the present invention.

FIG. 12 is a functional block diagram of an apparatus for detecting information embedded in an image according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 information recording carrier 2 picture 3 square or rectangular area 4 pixel 5a, 5b direction 7a, 7b diagonal 8 block

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 7-97822 (JP, B2) Koshio Matsui, Image Deep Encryption, Japan, Morikita Publishing, June 15, 1993, 1st edition, 1st edition, p. 20-22, p. 30-48 (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/387 G06T 1/00 500

Claims (3)

(57) [Claims] 2. The method according to claim 1, wherein the image printed on the record carrier has a square shape.
Or, assign a rectangular area, and
To form a plurality of partitioned pixels.
At least two or more pixels are aligned in the first direction
The first bit data "0" is recorded by painting
And at least two or more of the pixels in the second direction
The second bit data "1" is painted by lining up
The recorded information is embedded, a device for detecting the information, allocating the square or rectangular area on the record carrier,
This area is divided into three or more in each of the vertical and horizontal directions, and at least 9
A first unit for extracting the pixels partitioned as described above , and a predetermined square or rectangle assigned by the first unit
A first area having a shape, and the same square or rectangle as that of the first area , which is disposed continuously to the first area and in which the same bit data as the bit data of the first area are embedded.
A plurality of square or rectangular areas each including a second area having a shape are cut out and formed from the first area and the second area.
Second means for blocking an area that, said third means for detecting the brightness of each pixel constituting the blocked area by the second means, the third the first region as a unit based on the brightness of each pixel obtained by means Me calculated moving average value in each moving average can be calculated pixel, the moving average value obtained those
A fourth means for determining the brightness of the pixel; and calculating a difference between the brightness data detected by the third means and the brightness data detected by the fourth means for each pixel , and embedding bits. and fifth means for obtaining the detection data of the pattern, using the detection data obtained by the fifth means, before
Corresponding to pixels that are continuous in the first or second direction
Based on the cumulative value of the product of the detection data
At least two within the square or rectangular area
Filled so that upper pixels line up in the first direction
Or painted so as to line up in the second direction
Determining whether the bit pattern embedded in each area is “0” or “1” by determining whether the bit pattern is “0” or “1”. A device that detects information. 2. The method according to claim 1, wherein the square printed in the image printed on the record carrier is a square.
Or, assign a rectangular area, and
To form a plurality of partitioned pixels.
At least two or more pixels are aligned in the first direction
The first bit data "0" is recorded by painting
And at least two or more of the pixels in the second direction
The second bit data "1" is painted by lining up
The recorded information is embedded, a method of detecting the information, allocating the square or rectangular area on the record carrier,
This area is divided into three or more in each of the vertical and horizontal directions, and at least 9
A first step of extracting the pixels partitioned as described above , and a predetermined square or rectangle assigned in the first step
A first area having a shape, and the same square or rectangle as that of the first area , which is disposed continuously to the first area and in which the same bit data as the bit data of the first area are embedded.
A plurality of square or rectangular areas each including a second area having a shape are cut out and formed from the first area and the second area.
A second step of blocking an area to be blocked, a third step of detecting the brightness of each pixel constituting the area blocked in the second step, and the third step in which the first area is used as a unit . based on the brightness of each pixel obtained in step, Me calculated moving average values at each possible calculates the moving average pixel, the moving average value obtained those
A fourth step of setting the brightness of the pixel; and calculating a difference between the brightness data detected in the third step and the brightness data detected in the fourth step for each pixel, thereby forming an embedded bit. a fifth step of obtaining the detection data of the pattern, using the detection data obtained in the fifth step, before
Corresponding to pixels that are continuous in the first or second direction
Based on the cumulative value of the product of the detection data
At least two within the square or rectangular area
Filled so that upper pixels line up in the first direction
Or painted so as to line up in the second direction
Determining whether the bit pattern embedded in each of the regions is “0” or “1” by determining whether the bit pattern is embedded in the image. How to detect. 3. Squares in an image printed on a record carrier
Or, assign a rectangular area, and
To form a plurality of partitioned pixels.
At least two or more pixels are aligned in the first direction
The first bit data "0" is recorded by painting
And at least two or more of the pixels in the second direction
The second bit data "1" is painted by lining up
The recorded information is embedded, a recording medium for recording a computer program for detecting the information, allocating the square or rectangular area on the record carrier,
This area is divided into three or more in each of the vertical and horizontal directions, and at least 9
A first procedure for extracting the pixels partitioned as described above , and a predetermined square or rectangle assigned in the first procedure
A first area having a shape, and the same square or rectangle as that of the first area , which is disposed continuously to the first area and in which the same bit data as the bit data of the first area are embedded.
A plurality of square or rectangular areas each including a second area having a shape are cut out and formed from the first area and the second area.
A second procedure for blocking an area to be blocked, a third procedure for detecting the brightness of each pixel constituting the area blocked in the second procedure, and a third procedure for setting the first area as a unit . based on the brightness of each pixel obtained by the procedure, Me calculated moving average value in each moving average can be calculated pixel, the moving average value obtained those
A fourth procedure for determining the brightness of the pixel; and calculating, for each pixel , a difference between the brightness data detected in the third procedure and the brightness data detected in the fourth procedure. a fifth process for obtaining the detection data of the pattern, using the detection data obtained in the fifth step, before
Corresponding to pixels that are continuous in the first or second direction
Based on the cumulative value of the product of the detection data
At least two within the square or rectangular area
Filled so that upper pixels line up in the first direction
Or painted so as to line up in the second direction
A sixth procedure for determining whether the bit pattern embedded in each area is “0” or “1” by determining whether the bit pattern is embedded in each area. Medium.