JPH1083429A - Digital information recording method, decoding method and digital information decoding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital information recording method by which one kind of a specific pattern can show the directions to the head, tail, left and right of an information recording area and the information that shows the directions to the head, tail, left and right is hard to be lost and also which can identify the directions to the head, tail, left and right of the information recording area before reading recorded information in a square unit when digital information is recorded in a square unit that corresponds to a bit in an information recording area which is provided on a plane recording surface. SOLUTION: Directivity specific patterns 29 formed by adding marks (white or black) asymmetrically to 90 deg., 180 deg. and 270 deg. rotation within a recording surface into plural squares connected to a specified shape within an information recording area 23 are arranged to show the directions to the head, tail, left and right of position and information recording area 23 that is provided on a planar recording surface 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital information recording method for recording digital information on a recording surface as a two-dimensional pattern, and a decryption method for decrypting digital information recorded by such a recording method. Further, the present invention relates to a digital information decoding device for performing such a decoding method.

[0002]

2. Description of the Related Art Recently, matrixes corresponding to bits are virtually set in an information recording area provided in a planar recording surface such as paper, and data of 0 and 1 is stored in each of the above cells. 2. Description of the Related Art Recording methods for expressing digital information to be recorded as a two-dimensional pattern by adding white or black to represent them have been actively developed.

As shown in FIG. 22, the applicant of the present invention has previously described a method for reducing the reading error of a cell positioned inside an information recording area 23 provided in a recording surface 20. Proposed a method of arranging a specific pattern 22 for indicating the position of a grid (Japanese Patent Application No. 06-325).
275).

[0004] That is, in the information recording area 23 where information is actually recorded on the recording surface 20, a plurality of cells connected to a specific shape are inserted into a gap between the areas 21 representing original recording information. A plurality of specific patterns 22 each having a black and white pattern are arranged. In this example, a total of twelve specific patterns 22 of 4 × 3 in the rectangular information record 23 are arranged at fixed intervals in the vertical and horizontal directions (the vertical and horizontal intervals are the same or different). (Good) in a matrix. 23, ten specific patterns 22 belonging to the uppermost row, the lowermost row, the left column, and the right column in the arrangement of the specific patterns 22 are arranged along the outer periphery of the information recording area 23, and the remaining two Specific pattern 22
Are disposed inside (near the center) separated from the outer periphery of the information recording area 23.

[0005] As shown in FIG.
2 is a central part 51 composed of one square with black,
It comprises a first annular portion 52 composed of eight white cells surrounding the periphery thereof in a ring shape, and a second annular portion 53 composed of 16 black cells surrounding the periphery thereof in a ring shape. Have been. The whole is a square block including a total of 25 cells of 5 rows × 5 columns.

The specific pattern 22 is 1) relatively easy to find even if it is buried inside the information recording area 23. 2) The number of cells constituting the specific pattern 22 is relatively small, 25 cells. 3) Even when the same pattern appears in the vicinity of the specific pattern 22, it does not appear at a relatively distant position (a position vertically or horizontally shifted by four squares) (see FIG. 25). 4) White and black squares Are arranged in a well-balanced manner, so that they are not easily affected by dirt or bleeding. 5) As a reading algorithm, the central part (black) 5
Reference numeral 1 denotes a closed region surrounded by a first annular portion (white) 52, and the first annular portion 52 is also a second annular portion (black) 43.
It has the advantage that it can be easily found by examining the feature that forms a closed region surrounded by.

[0007] Information recording area 2 provided with specific pattern 22
FIG. 26 shows a method of mapping the recording information to No.3. FIG. 26 shows a portion 23 of a 35 × 20 grid corresponding to a part of the information recording area 23 shown in FIG.
A is shown. In the information recording area 23A, six (3 in the horizontal direction × 2 in the vertical direction) specific patterns 22 are arranged at every fifteen horizontal grids and at every fifteen vertical grids.
Of the 700 cells in the information recording area 23A, the number of cells used for the specific pattern 22 is 150, with 55 remaining cells.
Zero cells 21 are used to represent the original recorded information. Square 2 used to represent the original recorded information
, 550 (only some addresses are shown for simplicity). The address number is
From the leftmost cell in the first row in contact with the specific pattern 22 at the upper left corner, the address is from address 1 to address 10 to the right, and from address 11 to address 20 beyond the specific pattern 22 at the top center. The addresses are similarly assigned from the second row to the fifth row, and the cells in contact with the specific pattern at the right end of the fifth row are 10
It is at address 0. From the sixth line to the fifteenth line, the address increases by one from the cell at the left end of each line to the right.
From the 16th line to the 20th line, addresses are assigned beyond the central specific pattern 22, similarly to the 1st line to the 5th line. In this way, when the specific pattern 22 is arranged at the center of the row, the address is assigned beyond the specific pattern 22. The first bit information of the recording information corresponds to the cell of the address address 1, and the address having the bit information value "1" is black, and the address of "0" is white. Thereafter, the recording information is recorded in the same manner, and as a result, 550 cells 21 in the 550 cells 21 of the information recording area 23A are recorded.
Bits of digital information may be mapped.

[0008] As shown in FIG. 22, digital recording information of a format in which a specific pattern 22 is arranged in an information recording area 23 can be read as follows.

First, the specific pattern 22 is searched for in the information recording area 23, and the position information of the specific pattern 22 is determined based on the arrangement information that the specific pattern 22 is arranged in a matrix at a constant interval in each of the vertical and horizontal directions. obtain.

[0010] Next, as shown in FIG.
3 including four adjacent specific patterns 22 (M
The value of the cell 21 representing the original recording information is obtained for each (area including cells in the row N column).

More specifically, the position of the specific pattern 22 at the upper left (0 row and 0 column) is P ₀₀ , the position of the specific pattern 22 at the upper right (0 row and N column) is P _0N , and the lower left (M row and 0 column). The position P _M0 of the specific pattern 22 and the position of the specific pattern 22 at the lower right (M row and N column) are P _MN, and these four specific patterns 2
The position of the cell at the m-th row and the n-th column (m and n are arbitrary integers) in the area surrounded by 2 is defined as P _mn .

The points at which P ₀₀ and P _0N are internally _divided into n: (N−n) are P _0n , and the points at which P _M0 and P _MN are internally _divided into n: (N−n) are P _Mn , P _{The point at which 00} and P _M0 are internally _divided into m: (M−m) is P _m0 , and the point at which P _0N and P _MN are internally _divided into m: (M−m) is P
_{Assuming mN} , the position of the cell of P _mn to be obtained is represented as an intersection of a straight line L1 connecting P _0n and P _Mn and a straight line L2 connecting P _m0 and P _mN . Intersection point P between straight line L1 and straight line L2
_mn is also expressed as a point obtained by internally dividing the straight line L1 into m: (M−m) or a point obtained by internally dividing the straight line L2 into n: (N−n). The positions P ₀₀ , P _0N , P _M0 ,
Expressing the position P _mn of a cell in the area surrounded by these four specific patterns 22 using P _MN ,

(Equation 1) Becomes Thus, the position P _{mn of} each cell is obtained, and the value of each cell can be known by checking the value of this position P _mn .

Even when non-uniform distortion occurs over the entire recording surface 20, the distortion that occurs in such a small area surrounded by four adjacent specific patterns is almost proportional. Is approximated by Therefore, according to this method, digital information can be read accurately even if the recording surface 20 is slightly distorted.

[0014]

The recording surface 20
When decoding information recorded in the information recording area 23, it is extremely important to correctly identify the top, bottom, left and right directions of the information recording area 23 in order to prevent reading errors.

However, in the above information recording method,
The specific pattern 22 is 90 ° in the recording surface 20, 180 °
° and 270 ° (4 times rotational symmetry). If the specific patterns 22 are arranged at the same vertical and horizontal intervals in the information recording area 23, the information is recorded at the time of reading. The region 23 is 90 ° from the original direction, 1
There is a problem that it is difficult to identify whether the rotation has been made by 80 ° or 270 °. The specific pattern 22
Even if the vertical and horizontal intervals are different (for example, a specific pattern appears every 20 cells in the row direction and a specific pattern appears every 30 cells in the column direction),
It is difficult to distinguish 180 ° rotation.

Here, as shown in FIG. 28, the applicant assigns the specific patterns arranged at the four corners of the information recording area 23 to patterns 22J, 22J #, and 22K having different shapes and brightness from the remaining specific patterns 22. , 22K #, the specific patterns at the four corners can be set to 90
Japanese Patent Application No. 06-325275 proposes a technique in which the orientation of the information recording area 23 can be easily identified at the time of reading by making the information recording area 23 asymmetrical as a whole with respect to the rotation of 180 °, 180 ° and 270 °. ). However, FIG.
8, the specific patterns 22J and 22 at the four corners are used.
The number of cells constituting J #, 22K, 22K # becomes larger than the number of cells constituting the remaining specific pattern 22, and as a result, the procedure for setting and identifying the specific pattern becomes complicated. There's a problem. Also, specific patterns 2 at the four corners
When 2J, 22J #, 22K, and 22K # are crushed, there is a problem that information indicating the left and right directions of the information recording area 23 is lost.

As shown in FIGS. 29 (a) and 29 (b), the applicant has provided a margin 27 between specific patterns 22 arranged along the outer periphery of the information recording area 23. Part 2
7, a method of arranging an arrow-shaped pattern indicating the top and bottom right and left directions of the information recording area 23 and a method of arranging a similar arrow-shaped pattern in the segment G at the upper left corner of the information recording area 23 are also proposed. (Japanese Patent Application Laid-Open No. 07-056077)
issue). However, in these methods, when reading, it is possible to recognize the top, bottom, left and right only after once reading the information in the unit of cell. For this reason, there is a problem that if the orientation of the information recording area 23 at the top and bottom and right and left is wrong at first, the decoding of the recording information in mesh units must be performed again.

Accordingly, an object of the present invention is to record digital information in units of cells corresponding to bits in an information recording area provided on a planar recording surface, using one type of specific pattern. Digital that can indicate the direction of the top, bottom, left and right, the information indicating the direction of the top, bottom, left and right is hard to be lost, and the top, bottom, left, and right directions of the information recording area can be identified before reading the record information in mesh units An object of the present invention is to provide an information recording method.

Another object of the present invention is to provide a digital information decoding method suitable for reading digital information recorded by such a recording method.

It is another object of the present invention to provide a digital information decoding apparatus suitable for implementing such a decoding method.

[0021]

According to a first aspect of the present invention, there is provided a digital information recording method according to the first aspect, wherein a digital information recording area provided in a planar recording surface has a matrix shape corresponding to bits. A digital information recording method of virtually setting the cells, providing optically recognizable marks corresponding to the digital information to be recorded in each of the cells, and recording the digital information to be recorded as a two-dimensional pattern. In the information recording area, the mark is placed in a plurality of cells connected to a specific shape in the information recording area so as to indicate the position in the information recording area and the top and bottom directions of the information recording area. A characteristic feature is to arrange a direction specific pattern asymmetrically attached to the rotations of 90 °, 180 ° and 270 ° in the above.

According to the digital information recording method of the present invention, the direction specific pattern is 90 °, 180 ° in the recording surface.
Since the pattern is asymmetrical with respect to the rotation of .degree. And 270.degree., The direction of the top, bottom, left and right of the information recording area is indicated by one type of directionality specifying pattern. Therefore, the procedure for setting and identifying the directionality specifying pattern does not become complicated. In addition, since the directionality specifying pattern indicates the position in the information recording area and also indicates the top, bottom, left and right directions of the information recording area, the area representing the original recording information can be made relatively large. The information recording area is effectively used.

When a plurality of the one type of direction specifying pattern is arranged in the information recording area, even if a part of the direction specifying pattern (for example, four corners of the information recording area) is destroyed, the remaining direction specifying pattern is broken. The pattern indicates the top, bottom, left and right directions of the information recording area. Therefore, the information indicating the top, bottom, left and right directions of the information recording area is lost as compared with the case where different specific patterns having different shapes and different shades are provided at the four corners of the information recording area to indicate the top, bottom, left and right directions of the information recording area. It becomes difficult.

Also, at the time of reading, first, a direction specific pattern in the information recording area is searched for and the pattern is analyzed, so that the top, bottom, left and right of the information recording area can be determined.
Before reading the original recording information in the unit of mesh, the top, bottom, left and right directions of the information recording area are identified. Therefore, even if the top and bottom sides of the information recording area are wrong at first,
This eliminates the need to re-decode the recording information for each grid.

A digital information recording method according to a second aspect is the digital information recording method according to the first aspect,
The direction specificity pattern includes a central portion composed of a single cell shaded as the mark, and a first portion composed of a plurality of cells surrounded by the central portion and lighted as the mark. An annular portion and a second annular portion composed of a plurality of meshes shaded as the mark, surrounding the center portion in a continuous manner, and the mesh constituting the first annular portion, 90 ° around the center, 1
It is characterized in that it is connected in an asymmetrical shape with respect to rotations of 80 ° and 270 °.

According to the digital information recording method of the present invention, it is easy to find the direction specifying pattern in the information recording area owing to the configuration of the direction specifying pattern. In addition, the number of cells constituting the directionality specifying pattern is relatively small. Further, when the same or similar pattern appears in the vicinity as the original recording information, the directionality specifying pattern is unlikely to overlap the pattern. Further, the direction specific pattern is less susceptible to stains during printing and bleeding of ink. Also, the algorithm for finding the direction specific pattern is simplified.

According to a third aspect of the present invention, there is provided a digital information decoding method for decoding recording information recorded by the digital information recording method according to the first or second aspect, wherein the digital information decoding method includes the steps of: The direction specific pattern is searched for and its position is determined, and the brightness of the squares constituting the direction specific pattern is examined to determine the top and bottom left and right directions of the information recording area. Digital information recorded in an area of the information recording area other than the area occupied by the direction specific pattern is read based on the left and right directions and the position of the direction specific pattern.

In the digital information decoding method according to the third aspect, the top and bottom directions of the information recording area are obtained, and the information is recorded in an area of the information recording area other than the area occupied by the directionality specifying pattern. Since the read digital information (original recording information) is read, the original recording information can be correctly read by one decryption process.

According to a fourth aspect of the present invention, in the digital information decoding method according to the third aspect, when the direction identification pattern is the direction identification pattern according to the second aspect, the direction identification is performed. Calculating the center of gravity of the center of the pattern and the center of gravity of the first annular portion, respectively;
It is characterized in that the top, bottom, left and right directions of the information recording area are obtained based on the center of gravity of the center portion and the center of gravity of the first annular portion.

In the digital information decoding method according to the fourth aspect, when the direction specific pattern is the direction specific pattern according to the second aspect, the center of gravity of the center of the direction specific pattern and the first annular portion are provided. The left and right directions of the information recording area are obtained based on the center of gravity of the information recording area, so that the left and right directions of the information recording area can be identified by simple processing.

The meshes forming the first annular portion of the direction specificity pattern are 90 ° around the central portion,
Since they are connected in an asymmetric shape with respect to the rotations of 180 ° and 270 °, the position of the center of gravity of the central portion does not coincide with the position of the center of gravity of the first annular portion. Therefore, the top, bottom, left and right directions of the information recording area are always required.

A digital information decoding method according to a fifth aspect is a digital information decoding method for decoding recording information recorded by the digital information recording method according to the first or second aspect, wherein the digital information decoding method comprises the steps of: After reading the two-dimensional pattern by the reading means and creating bitmap data representing the two-dimensional pattern, searching for the directional specification pattern in the bitmap data to determine its position, The top and bottom directions of the information recording area are determined by examining the brightness of the cells constituting the pattern, and the information recording area that appears in the bitmap data is determined based on the obtained top and bottom directions of the information recording area. A rotation process is performed on the bitmap data so that the orientation is correct, and the position of the directionality specifying pattern after the rotation process is changed. Based on, characterized in that reading the digital information recorded in a region other than the region occupied by the directional specific pattern of the information recording area.

In the digital information decoding method according to the fifth aspect, since the top and bottom and right and left of the information recording area are oriented in the correct direction by performing the rotation processing, the subsequent processing for decoding the original recording information can be easily performed. Will be Further, the process of reading the two-dimensional pattern recorded on the recording surface by the reading means only needs to be performed once.

When the information recording area is rectangular,
An error in the right and left directions of the information recording area is usually 90 °,
Often 180 ° or 270 °. Performing a 90 °, 180 °, or 270 ° rotation process (coordinate conversion process) on the bitmap data is a known technique, and is relatively easily performed.

A digital information decoding method according to claim 6 is a digital information decoding method for decoding recording information recorded by the digital information recording method according to claim 1 or 2, wherein the digital information is recorded on the recording surface. After reading the two-dimensional pattern by the reading means and creating bitmap data representing the two-dimensional pattern, searching for the directional specification pattern in the bitmap data to determine its position, The direction of the top and bottom of the information recording area is determined by examining the brightness of the cells constituting the pattern, and the information recording area is oriented correctly with respect to the reading unit based on the determined top and bottom of the information recording area. The reading means and the recording surface are relatively rotated so that the two-dimensional pattern recorded on the recording surface is again read by the reading means. Reading, creating bitmap data representing the two-dimensional pattern, searching the bitmap data for the direction specifying pattern to determine its position, and recording the information based on the position of the direction specifying pattern. Digital information recorded in an area other than the area occupied by the directionality specifying pattern in the area is read.

In the digital information decoding method according to the sixth aspect, after the reading means and the recording surface are relatively rotated so that the information recording area is oriented correctly with respect to the reading means, reading is performed again. Therefore, unlike the fifth aspect, there is no need to perform a rotation process (coordinate conversion process) on the bitmap data. Therefore, the process of decoding the original recorded information is easily performed. Further, the memory required for the bitmap data coordinate conversion process is not required. Further, since the relative rotation between the reading means and the recording surface is performed continuously, the rotation angle can be set arbitrarily.

According to a seventh aspect of the present invention, there is provided a digital information decrypting apparatus for decrypting digital information recorded by the digital information recording method according to the second aspect, wherein Reading means for reading a dimensional pattern and outputting bitmap data representing the two-dimensional pattern; searching means for searching for the directional specific pattern in the bitmap data to determine its position; The center of gravity of the dot forming the center portion and the center of gravity of the dot forming the first annular portion are calculated, and the center of gravity of the center and the center of gravity of the first annular portion are compared. An inclination detecting means for detecting an inclination of the information recording area in the bitmap data, and an inclination detecting means for detecting the inclination of the information recording area detected by the inclination detecting means. Out of rotation processing of 0 °, 90 °, 180 ° or 270 ° with respect to the bitmap data, a rotation processing in which the inclination of the information recording area in the bitmap data after the rotation processing is within ± 45 °. A bitmap data rotating unit for performing the selected rotation processing on the bitmap data, and the directionality of the information recording area after the rotation processing based on the position of the directionality specifying pattern. Information decoding means for reproducing digital information recorded in an area other than the area occupied by the specific pattern, and output means for outputting the digital information reproduced by the information decoding means are provided.

The digital information decrypting apparatus according to claim 7 operates as follows.

First, the reading means reads the two-dimensional pattern recorded on the recording surface and outputs bitmap data representing the two-dimensional pattern.

Next, the searching means searches the bitmap data for the direction specifying pattern to determine its position.

Next, the inclination detecting means calculates the center of gravity of the dot forming the center of the directionality specifying pattern and the center of gravity of the dot forming the first annular portion, and calculates the center of gravity of the center. By comparing the position with the position of the center of gravity of the first annular portion, the inclination of the information recording area in the bitmap data is detected. This process is relatively simple.

Next, the bit map data rotating means sets the angle 0 °, 90 ° with respect to the bit map data based on the inclination of the information recording area detected by the inclination detecting means.
Among the rotation processes of °, 180 °, or 270 °, a rotation process in which the inclination of the information recording area in the bitmap data after the rotation process is within ± 45 ° is selected. Then, the selected rotation processing is performed on the bitmap data.

Next, based on the position of the direction specific pattern after the rotation processing, the information decoding means records the information in an area of the information recording area after the rotation processing other than the area occupied by the direction specific pattern. To reproduce the digital information.

Then, the output means outputs the digital information reproduced by the information decoding means.

Thus, according to the digital information recording apparatus of the present invention, it is possible to decode the digital information recorded by the digital information recording method of the present invention.

The digital information decrypting apparatus according to claim 8 is a digital information decrypting apparatus for decrypting digital information recorded by the information recording method according to claim 2, wherein the two-dimensional information is recorded on the recording surface. Reading means for reading a pattern and outputting bitmap data representing the two-dimensional pattern; searching means for searching for the direction specific pattern in the bitmap data to determine its position; The position of the center of gravity of the dot forming the center and the position of the center of gravity of the dot forming the first annular portion are respectively calculated, and the position of the center of gravity of the center and the first position are calculated.
By comparing the position of the center of gravity of the annular portion, the inclination detecting means for detecting a relative inclination in the rotation direction between the reading means and the information recording area, based on the inclination detected by the inclination detecting means, A mechanical rotating unit that relatively rotates the reading unit and the recording surface so that the inclination is eliminated, and the direction specifying pattern occupies the information recording area based on a position of the direction specifying pattern. An information decoding means for reproducing digital information recorded in an area other than the area, and an output means for outputting the digital information reproduced by the information decoding means.

The digital information decrypting apparatus according to claim 8 operates as follows.

First, the reading means reads the two-dimensional pattern recorded on the recording surface and outputs bitmap data representing the two-dimensional pattern.

Next, the search means searches the bitmap data for the direction specifying pattern to determine its position.

Next, the inclination detecting means calculates the position of the center of gravity of the dot forming the center of the directionality specifying pattern and the position of the center of gravity of the dot forming the first annular portion, and calculates the center of gravity of the center. By comparing the position with the position of the center of gravity of the first annular portion, a relative inclination in the rotation direction between the reading means and the information recording area is detected. This process is relatively simple.

Next, mechanical rotating means relatively rotates the reading means and the recording surface based on the inclination detected by the inclination detecting means so that the inclination is eliminated.

Next, the reading means reads the two-dimensional pattern recorded on the recording surface again and outputs bitmap data representing the two-dimensional pattern.

Next, the searching means searches the bitmap data again for the directionality specifying pattern to determine its position.

Next, information decoding means reproduces digital information recorded in an area other than the area occupied by the direction specific pattern in the information recording area, based on the position of the direction specific pattern.

The output means outputs the digital information reproduced by the information decoding means.

Thus, according to the digital information recording apparatus of the present invention, it is possible to decode the digital information recorded by the digital information recording method of the present invention.

[0057]

Embodiments of the present invention will be described below in detail.

FIG. 1 shows an example of recorded information recorded by the digital information recording method according to one embodiment. In this digital information recording method, matrix squares corresponding to the bits of digital information are virtually set on the recording surface 20, and "0" is marked as an optically recognizable mark in each of the above cells. White (bright) or black (dark) representing "1". Thus, the digital information is recorded on the recording surface 20 as a two-dimensional pattern.

In the information recording area 23 where information is actually recorded on the recording surface 20, a specific position is indicated so as to indicate the position in the information recording area 23 and the top, bottom, left and right directions of the information recording area 23. A plurality of direction specifying patterns 29 each having a predetermined pattern of black and white are arranged in a plurality of cells connected to the shape of. In this example, the direction specifying pattern 2
Reference numeral 9 denotes the same spatial and vertical spatial periods at which the directionality specifying pattern 29 appears at regular intervals in the vertical and horizontal directions in the rectangular information recording area 23, specifically, every 15 cells in the vertical direction and every 15 cells in the horizontal direction. And are arranged in a matrix of 4 rows and 3 columns. The four corners of the information recording area 23 are occupied by the directionality specifying patterns 29. Note that FIG.
Shows a simplified arrangement of the directionality specifying pattern 29 in the information recording area 23. Original recording information is recorded in an area 21 other than the area occupied by these directionality specifying patterns 29 in the information recording area 23.

As shown in FIG. 3, the direction specification pattern 29 is a rectangular block including a total of 30 cells of 5 rows × 6 columns, and is composed of one cell with black. A first annular portion 42 composed of eleven white cells surrounding the center portion 41 in an annular shape and a second annular portion composed of 18 black cells surrounding the periphery in a circular shape. And a section 43. The first annular portion 42 includes eight white cells directly surrounding the central portion 41,
Of these, three white cells in contact with the left side of the three white cells in the left column. As a result, the direction specifying pattern 29 is 90 ° in the recording surface 20,
It is asymmetric for 180 ° and 270 ° rotation. That is, since the direction specifying pattern 29 is a rectangular block of 5 rows × 6 columns as a whole,
It is asymmetrical for rotations of ° and 270 °. Further, since the center of gravity of the first annular portion 42 is shifted to the left with respect to the center of gravity of the central portion 41,
Is also asymmetric for 180 ° rotation.

FIG. 4 shows another example of a pattern that can be used as the direction specifying pattern. The pattern 29A shown in FIG. 4A is a rectangular block including a total of 30 cells of 5 rows × 6 columns and 1
A central portion 41A composed of nine cells and a first annular portion 42 composed of nine cells marked with white surrounding the periphery in a ring shape
A and black 2 surrounding it in a ring
The second annular portion 43A is composed of zero cells. The first annular portion 42A includes eight white cells directly surrounding the central part 41A, and one white cell in contact with the left side of the white cell in the center of the left column. As a result, this pattern 29A is the same as the direction specifying pattern 2 described above.
Like FIG. 9, it is asymmetric with respect to rotations of 90 °, 180 ° and 270 ° within the recording surface 20. Fig. 4 (b)
Is a rectangular block including a total of 30 cells of 5 rows × 6 columns, including a central portion 41B composed of two cells marked with black, and a white portion surrounding the cell in a ring shape. The first annular portion 42B is made up of 10 cells marked with a circle, and the second annular portion 43B is made up of 18 cells marked with black surrounding the periphery thereof. Also, the pattern 29C shown in FIG.
A central closed area 41C made up of six white cells connected to a rectangle of 2 rows × 3 columns, and an annular portion 42C made up of 14 black cells surrounding the periphery in a ring shape It is composed of These patterns 29B, 29C
Is asymmetric for rotations of 90 ° and 270 ° in the recording surface 20, but is symmetrical for rotation of 180 °. Therefore, these patterns 29B, 29C
Can be employed only in applications where 180 ° rotation is not a problem.

FIG. 5 shows a schematic configuration of a digital information recording apparatus suitable for carrying out the digital information recording method of the present invention. This apparatus includes an input device 82 as input means for inputting digital information to be recorded, an information recording device 81 as a pattern generating means for generating a two-dimensional pattern to be printed on a recording surface, and a two-dimensional A printing device 83 as printing means for printing the pattern on the recording surface. The input device 82 includes, for example, a keyboard, a database, and the like, and can read various data. The information recording device 81 includes the input unit 8
4, a data conversion unit 85, an output unit 86, and a data conversion (coding) algorithm 87. The input unit 84 receives data from the input device 82 as input information and passes it to the data conversion unit 85. Data converter 85
Converts the input information received from the input unit 84 into a two-dimensional pattern expression format based on a data conversion (coding) algorithm 87, and passes the converted information to the output unit 86 as output information. The output unit 86 includes the data conversion unit 8
5 is output to the printing device 83.
Note that, generally, the output information passed to the printing device 83 is a bit image. The printing device 83 is configured by, for example, a dot printer, a laser printer, or the like according to a required printing accuracy.

Using this information recording apparatus, various data to be recorded can be recorded on the recording surface 20 of the record carrier as shown in FIG. 1 according to the flow shown in FIG.

First, the input device 82 reads various data (S 01), and reads the read data into the information recording device 8.
1 to the input unit 84.

In the information recording device 81, the data conversion unit 85 that has received data via the input unit 84 performs the following processing based on a data conversion (coding) algorithm.

(I) First, the size of the information recording area 23 is determined according to the size of the data (S02). The size of the information recording area 23 is determined by the recording information and the number of directionality specifying patterns 29 to be added. Information recording area 2
3 has a constant width, or the information recording area 23
In some cases, a restriction such as a square shape may be added.
If the size of the recording information is determined in advance,
This step is not required.

(Ii) Next, the directivity specifying pattern 29 is arranged at a predetermined position in the information recording area 23 (S
03). As this arrangement, for example, a matrix arrangement having the same spatial period in the vertical and horizontal directions such that the direction specification pattern 29 appears in every 15 vertical cells and every 15 horizontal cells is adopted.

(Iii) Next, the bit information of the data is allocated to the cell 21 representing the original recording information in the information recording area 23 according to a predetermined mapping (S
04).

The output unit 8 of the information recording device 81
The printing device 83 sends the recording information passed from the
(S05).

In this way, digital information is recorded on the recording surface 20 of the record carrier. In this digital information recording method, the direction specifying pattern 29 is set to 90 °, 1
Since the pattern is asymmetrical with respect to the rotations of 80 ° and 270 °, the right and left directions of the information recording area 23 can be indicated by one type of directionality specifying pattern 29. Therefore, the procedure for setting and identifying the directionality specifying pattern 29 does not become complicated. In addition, since the direction specifying pattern 29 indicates the position in the information recording area 23 and also indicates the top, bottom, left and right directions of the information recording area 23, the area 21 representing the original recording information is made relatively large. The information recording area 23 can be used effectively.

When a plurality of one type of directionality specifying patterns 29 are arranged in the information recording area 23 as described above,
Even if the directional specification patterns 29 in a part (for example, four corners of the information recording area 23) are crushed, the left and right directions of the information recording area 23 can be indicated by the remaining directional specification patterns 29. Therefore, as compared with the case where different specific patterns having different shapes and different shades are provided at the four corners of the information recording area 23 to indicate the top and left and right directions of the information recording area 23, the information indicating the top and left and right directions of the information recording area 23 is displayed. Is less likely to be lost.

At the time of reading, first, the information recording area 2
3 can be obtained by analyzing the pattern and searching for the direction specifying pattern 29 in the direction 3, and before reading the original recording information of the grid unit, the right and left sides of the information recording area 23 are read. The orientation can be identified. Therefore, even if the orientation of the information recording area 23 is right and left at first, there is no need to re-decode the original recording information in mesh units (details will be described later).

FIG. 7 shows a schematic configuration of a digital information decoding apparatus according to an embodiment of the present invention. This device includes a reading device 92 as reading means, an information decoding device 91, and an output device 93 as output means.

The reading device 92 is composed of, for example, an image scanner, a CCD (Charge Coupled Device) camera, or the like according to the required reading accuracy, and records information (two-dimensionally) printed on the recording surface 20 such as paper. Pattern) can be read.

The information decoding device 91 includes an input unit 94 and a data conversion unit 95 serving as a search unit and a tilt detection unit.
, Output unit 96 and data conversion (decryption) algorithm 9
7 and a rotation processing unit 98 as bitmap data rotation means. The input unit 94 receives data from the reading device 92 as input information, and
Pass to Note that, in general, the input unit 9 is
The input information passed to 4 is a bit image. The data conversion unit 95 converts the input information received from the input unit 94 into
Decoding is performed based on a data conversion (decoding) algorithm, and is passed to the output unit 96 as output information. The output unit 96 outputs the output information received from the data conversion unit 95 to the output device 93. The rotation processing unit 98 performs a rotation process of 90 °, 180 °, or 270 ° on the bitmap data as input information according to an instruction from the data conversion unit 85. The output device 93 includes, for example, a display and a database, and displays or stores information received from the output unit 96.

Here, the data conversion (coding) shown in FIG.
The algorithm 87 and the data conversion (decoding) algorithm 97 in FIG. Therefore, the information recorded on the recording surface 20 by the recording device of FIG. 5 can be decrypted by the decryption device of FIG. 7, and the original data can be reproduced.

Using this information decrypting device, information recorded on the recording surface 20 of the record carrier as shown in FIG. 1 can be decrypted according to the flowchart shown in FIG. Note that, as shown in FIG. 1, the two-dimensional pattern to be decoded has directionality specifying patterns 29 arranged in a matrix at the same spatial period in the vertical and horizontal directions in the information recording area 23 and at the four corners of the information recording area 23. It is assumed that the direction specifying pattern 29 is arranged.

First, the reading device 92 reads information (two-dimensional pattern) recorded on the recording surface 20 of the record carrier (S 11), and passes bitmap data representing the information to the input unit 94 of the information decoding device 91.

In the information decoding device 91, the data conversion unit 95 receives the data via the input unit 94 and performs the following processing based on the data conversion (decryption) algorithm 96.

(I) First, the bitmap data is searched for the direction specifying pattern 29 (the method for searching for the direction specifying pattern 29 will be described later in detail). The direction specifying patterns 29 arranged at the four corners are extracted (S12). At this time, the position (position information) of the directionality specifying pattern 29 is obtained.

The position of the directionality specifying pattern 29 is represented by the position of the center of gravity of the central portion 41. The position of the center of gravity of the center 41 in the bitmap data can be obtained by checking the positions of all the black bits (see FIG. 15) constituting the center 41 and averaging them.

(Ii) Next, the size of one cell is determined by examining the brightness of the cells constituting the directionality specifying pattern 29 arranged at the four corners (S13).

(Iii) Next, the remaining directionality specifying patterns 29 are extracted based on the position information of the directionality specification patterns 29 arranged at the four corners and the predetermined arrangement information (S14).

Here, the predetermined arrangement information is, for example, a directional specification pattern 2 such that a directional specification pattern 29 appears every 15 vertical cells and every 15 horizontal cells.
9 is the information on the arrangement of 9. It is assumed that the directionality specifying patterns 29 are arranged in a matrix with the same spatial period in the vertical and horizontal directions.
There is no change for the rotation of 270 °.

(Iv) Next, the direction of the top, bottom, left and right of the information recording area 23 is obtained by analyzing the directionality specifying pattern 29 (the method of obtaining the left, right, top and bottom of the information recording area 23 will be described later). explain in detail.).

(V) If the obtained top and bottom directions of the information recording area 23 are not correct, the rotation processing unit 9
8, the rotation process is performed on the bitmap data so that the top and bottom and right and left of the information recording area 23 are oriented correctly (S15). In this step (S15), a step (S13) of searching for the directionality specifying patterns 29 at the four corners, and a step (S14) of searching for the remaining directionality specifying patterns 29.
You may go between them.

(Vi) Next, based on the extracted position information of each directionality specifying pattern 29, the position of the cell 21 representing the original recording information is determined (S16). Here, it is assumed that the position of the cell 21 representing the original recording information is determined by the method already described with reference to FIG.

(Vii) Next, the information recorded in such a cell 21 is read out according to a predetermined mapping (S17).

The output unit 9 of the information decoding device 91
The output device 93 outputs the output information passed from 6 (S18).

In this manner, the digital information recorded on the recording surface 20 of the record carrier as shown in FIG. 1 can be decoded. According to this digital information decryption method, the original recorded information is decrypted after determining the top and bottom directions of the information recording area 23, so that the original recorded information can be correctly decrypted by one decryption process. .

Further, by performing a rotation process on the bitmap data, the top and bottom and right and left of the information recording area 23 are oriented in a correct direction, so that the subsequent process of decoding the original recorded information can be easily performed. The process of reading the two-dimensional pattern recorded on the recording surface 20 by the reader 92 can be completed only once.

(1) Next, a method for searching for the above-described directionality specifying pattern 29 will be described in detail.

FIG. 9 shows a direction specifying pattern 29 arranged at the upper left corner of the recording information area 23 in the bitmap data.
Is schematically shown. When searching for the directionality specifying pattern 29 at the upper left corner, scanning is performed diagonally from the upper left corner of the bitmap data (the direction indicated by the arrow in the figure). Assuming that the outside of the information recording area 23 is a white bit, the black bit first appearing in the scan in the oblique direction is the black bit forming the directionality specifying pattern 29 at the upper left corner. Thereby, the direction specific pattern 2 at the upper left corner
9 can be found. In addition, FIGS. 10 (a), (b),
As shown in (c), each of the information recording areas 23 has 90
Even if the image is rotated in the directions of °, 180 °, and 270 °, the first black bit that appears in the scan in the oblique direction is the black bit that forms the directionality specifying pattern 29 arranged at any of the four corners. Of course, the directionality specifying patterns 29 originally arranged at the upper right corner, the lower left corner, and the lower right corner of the information recording area 23 also correspond to the upper right corner,
Scanning diagonally from the lower left and lower right corners can be found similarly.

[0094] Of the directionality specifying patterns 29 arranged in the information recording area 23, the remaining directionality specifying patterns 29 arranged at other than the four corners are obtained by combining the position information of the directionality specification patterns 29 arranged at the four corners with the position information. A search is performed as follows based on the determined arrangement information.

For example, when searching for the directionality specifying patterns 29 (excluding the four corners) arranged along the four sides of the information recording area 23, first, the directionality specification patterns 29 at the four corners are analyzed to obtain information recording. The approximate size of a virtual cell constituting the area 23 is obtained. That is, if the shape of the virtual mesh is a square, the length of one side of the mesh can be known by calculating the area of the central portion 41 of the directionality specifying pattern 29 and calculating the square root thereof. If it is known from the predetermined arrangement information that the directionality specifying patterns 29 are arranged in a matrix so as to appear every 15 cells vertically and every 15 cells horizontally, the direction specification patterns at the upper left corner It is expected that the next direction specification pattern 29 will appear at a position advanced by 15 squares from 29 toward the direction of the direction specification pattern 29 in the upper right corner. By examining the vicinity of the expected position, it is possible to find the directionality specifying pattern 29 arranged on the right side of the directionality specification pattern 29 at the upper left corner. Thereafter, by repeating the same operation, all the direction specifying patterns 29 along the four sides can be found.

The direction specifying pattern 2 near the center is
In the case of searching for the line 9, for example, on the assumption that the directionality specifying patterns 29 are arranged in a matrix in accordance with predetermined arrangement information, for example, a straight line connecting the left and right corresponding directionality specifying patterns 29 is formed. By obtaining an intersection with a straight line connecting the corresponding upper and lower directionality specifying patterns 29 and examining the vicinity of the position of the intersection, the directionality specifying pattern 29 near the center can be found.

Here, whether or not the pattern existing near the expected position is the directionality specifying pattern 29 is recognized as follows. That is, in the directionality specifying pattern 29, the central portion (black square) 41 forms a closed region surrounded by white squares, and the first annular portion (white square) 42 defines a closed region surrounded by black squares. Since the pattern has a feature of being composed, it is recognized by checking whether a pattern existing near the expected position has such a feature. However,
This recognition method merely checks whether or not a configuration requirement of the directionality specifying pattern 29 is satisfied.
Since the value of each cell is not checked, there is a possibility that another pattern (for example, the specific pattern 22 shown in FIG. 24) may be erroneously recognized as the directionality specifying pattern 29. However, since the vicinity of the expected position where the directionality specifying pattern 29 should appear is checked, if normal recording has been performed, a pattern having the same characteristics (necessary conditions) appears near the expected position. There should not be. For example, as shown in FIG. 11, a pattern having the same feature appears only at a position shifted by four squares from the original directionality specifying pattern 29. Therefore, the possibility that another pattern is erroneously recognized as the directionality specifying pattern 29 is low. Further, even if another pattern is erroneously recognized as the direction specifying pattern 29, for example, after extracting all of the direction specifying patterns 29, it is checked whether or not the respective direction specifying patterns 29 are arranged in a matrix. In addition, a pattern that is erroneously recognized can be ignored. In this case, it is also possible to perform a more accurate check only on the directionality specifying pattern 29 which is considered to have a high possibility of erroneous recognition. Thus, as a method of recognizing the directionality specifying pattern 29,
In practice, a method of checking whether or not the above characteristic exists is sufficient.
9 can be recognized.

FIG. 12 shows an example of a processing flow for recognizing whether or not the pattern existing near the expected position is the directionality specifying pattern 29. Note that this recognition processing is performed on bitmap data read from the reading device (as shown in FIG. 15, consisting of bits having a smaller size than the cells constituting the two-dimensional pattern).

First, when the direction specifying pattern 29 is arranged in the information recording area 23 according to the predetermined arrangement information, the position where the direction specifying pattern 29 should appear in the bitmap data is predicted. (S61), a position P serving as a search reference in the bitmap data is determined (S62). It is checked whether or not the dot at the reference position P is black (S63). If the dot is black,
The process proceeds to step S66 on the assumption that the dot constitutes the central portion 41.

On the other hand, if the dot at the reference position P is not black at step S63, the next search position is determined within a certain range from the reference position P (S64), and the dot at that search position is black again. Find out if. However, if all of the search within the predetermined range from the reference position P have been performed, but a black dot corresponding to the central portion 41 of the directionality specifying pattern 29 has not been found (S65), the search has failed (S65).
76) The process ends.

In step S66, a recursive search is made for black dots connected vertically, horizontally, and diagonally to the dot at the reference position P. Then, it is determined whether or not the number of connected black dots is within a certain range (S67). If the number of connected black dots exceeds a certain number, it is determined that the area to which the black dots are connected is not closed, or that even if it is closed, the central portion 41 is too large. If the number of connected black dots is less than a certain number, it is determined that the noise is not the central portion 41 but merely noise. If the number of these connected black dots is not within a certain range, the process returns to step S64 to repeat the process.

On the other hand, if the number of connected black dots is within a certain range (S67), the flow advances to step S68 to set the width and height of the connected area of the black dots within the certain range. Check if there is, and check the shape. The width of the connected area is obtained by subtracting the minimum value from the maximum value of the X coordinate of the connected area, and the height of the connected area is obtained by subtracting the minimum value from the maximum value of the Y coordinate of the connected area. Represented as If the width and height of the area where the black dots are connected are not within a certain range, step S64
Return to and repeat the process.

On the other hand, if the width and height of the area where the black dots are connected are within a certain range (S68), it is determined that the area where the black dots are connected is the central portion 41, and step S69 is performed. Proceed to.

Next, in step S69, the first annular portion 42
Start checking for One black dot (the one with the smallest Y coordinate) at the bottom of the connected area of the black dots determined to be the center portion 41 is selected (S6).
9). Then, as shown by an arrow in FIG. 13, the search is performed downward from the area (the center portion 41), and the black color that appears next to the white dot (which is considered to be the white dot forming the first annular portion 42) is obtained. A dot (considered as a black dot constituting the second annular portion 43) is searched (S70). If the next black dot is not found within a certain distance from the area of the white dot, the area of the white dot is used as the direction specifying pattern 29.
It is determined that it is not the first annular portion 42 (S71), and the process returns to step S64 to repeat the process. On the other hand, when the next black dot is found within a certain distance from the white dot area (S71), it is considered that the black dot forms the second annular portion 43 of the directionality specifying pattern 29. Then, as indicated by an arrow in FIG. 13, the left method (following the wall of the maze while putting the left hand on the wall) along the inner circumference of the region considered to be the second annular portion 43, that is, the boundary between the black dot and the white dot. Method) (S72). If one round cannot be made within a certain step, it is determined that the white dot area is not closed or that it is too large even if it is closed (S73). Further, when one round by the left method is performed counterclockwise, it is considered that a white dot area is not closed but a closed area of some black dot is searched as shown in FIG. (S74). In these cases, the process returns to step S64 to repeat the process. Then, by clearing all the steps S61 to S74, the directionality specifying pattern 29 can be recognized (S75).

(2) Next, a method of analyzing the directionality specifying pattern 29 to determine the top, bottom, left and right directions of the information recording area 23 will be described.

The direction specifying pattern 29 is 90 °, 180 °
Since it is asymmetrical with respect to the rotation of ° and 270 °, by examining the directionality specifying pattern 29, the rotation of the information recording area 23 by the right and left directions, in other words, by 90 °, 180 ° or 270 ° from the correct direction. You can know if it has been added.

That is, as shown in FIG.
If the position of the center of gravity G1 of (1) is (0, 0), and the width and height of one cell are 1, the first annular portion 42 is formed.
The position of one white cell is (-2, -1), (-1,-)
1), (0, -1), (1, -1), (-2, 0),
(-1, 0), (1, 0), (-2, 1), (-1,
1), (0, 1) and (1, 1). By design,
The center of gravity position G2 of the first annular portion 42 is a point (-0.545, 0) obtained by averaging the positions of the eleven white cells. As can be seen from this, the center of gravity G2 of the first annular portion 42 is shifted to the left with respect to the center of gravity G1 of the center 41.
Therefore, the position of the center of gravity of the central portion 41 and the position of the center of gravity of the first annular portion 42 are obtained on the bitmap data as shown in FIG.
3 can be obtained. In order to determine the position of the center of gravity of the central portion 41 on the bitmap data, the positions of all the black bits constituting the position are averaged. Similarly, in order to determine the position of the center of gravity of the first annular portion 42 on the bitmap data, the positions of all the white bits constituting the first annular portion 42 are averaged.

In the case where a plurality of direction specifying patterns 29 exist in the information recording area 23, it is possible to know the top, bottom, left and right directions of the information recording area 23 more accurately by judging a plurality of pieces of comparison information. Can be. Specifically, for each of the plurality of directionality specifying patterns 29, for each of the first annular portions 42 with respect to the average position of all the black bits constituting each central portion 41.
Is obtained by comparing the average position of all the white bits forming the horizontal and vertical directions (tilt).

Even when the direction specifying pattern 29A shown in FIG. 4A is employed, the position of the center of gravity of the center portion 41A and the position of the center of gravity of the first annular portion 42A are compared. The top, bottom, left and right directions of the information recording area 23 can be obtained. However, since the distance between the position of the center of gravity of the center portion 41A and the position of the center of gravity of the first annular portion 42A is smaller than the case of the directionality specifying pattern 29 by design, the identification accuracy is slightly lowered.

When the orientation of the top and bottom of the information recording area 23 is obtained in this way, the bitmap data is set so that the top and bottom and right and left of the information recording area 23 are oriented correctly in order to smoothly proceed with subsequent decoding processing. On the other hand, a rotation process can be performed. That is, the bitmap data may be rotated such that the position of the center of gravity of the first annular portion 42 is immediately to the left of the center of gravity 41 of the center portion 41 of the directionality specifying pattern 29.

0 °, 90 ° to the bitmap data
Applying a rotation process of °, 180 °, or 270 ° (rotation process of 0 ° means that rotation is not actually performed) can be easily performed using a known technique. Therefore, as shown in FIG.
It is relatively easy to set a range of ± 45 ° as the allowable range of the inclination of 3 and to set the inclination of the information recording area 23 within this allowable range. Of course, by performing a rotation process (complicated as a process) that can be set at an arbitrary angle on the bitmap data, the first annular portion 42 is moved relative to the center of gravity of the central portion 41 of the directionality specifying pattern 29. Can be corrected so that the position of the center of gravity of the right side is rightward. However, considering the accuracy of the inclination obtained by comparing the position of the center of gravity of the center portion 41 of the directionality specifying pattern 29 with the position of the center of gravity of the first annular portion 42,
The information on the inclination is used only for identifying whether the inclination of the information recording area 23 from the correct direction is closer to 90 °, 180 ° or 270 °, and the inclination of the information recording area 23 is corrected by another process. It may be realistic.

FIG. 18 shows a schematic configuration of a digital information decoding apparatus according to another embodiment of the present invention. Note that the same components as those of the digital information decoding device shown in FIG. 7 are denoted by the same reference numerals. This device includes a reading device 92 as reading means, an information decoding device 91 #, a rotating device 99,
An output device 93 is provided as output means.

The information decoding device 91 # has a rotation processing unit 98 # instead of the rotation processing unit 98 of the information decoding device 91 in FIG. The rotation processing unit 98 #
5 is an information recording area 23 on the bitmap data obtained.
And outputs an instruction to relatively rotate the reading device 92 and the recording surface 20 so that the inclination is eliminated in accordance with the top and bottom left and right directions (inclination). The rotation device 99 includes a rotation processing unit 9.
The reading device 92 and the recording surface 20 are relatively rotated according to the instruction output by 8 #. For example, as shown in FIG. 19, when the recording surface 20 is fixed, the camera 92 serving as the reading device is continuously rotated around its optical axis. Alternatively, as shown in FIG. 20, when the camera 92 as the reading device is fixed, the recording surface 20 is continuously rotated by rotating the stage 99a. This allows
The right and left sides of the information recording area 23 are correct on the bitmap data.

This information decoding apparatus operates in accordance with the flow shown in FIG. 21 and the recording surface 2 of the record carrier as shown in FIG.
The information recorded in 0 can be read. Note that, as shown in FIG. 1, the two-dimensional pattern to be decoded has directionality specifying patterns 29 arranged in a matrix at the same spatial period in the vertical and horizontal directions in the information recording area 23 and at the four corners of the information recording area 23. It is assumed that the direction specifying pattern 29 is arranged.

First, the reading device 92 reads information (two-dimensional pattern) recorded on the recording surface 20 of the record carrier (S21), and passes bitmap data representing the information to the input unit 94 of the information decoding device 91 #. .

In the information decoding device 91 #, the data conversion unit 95 receives the data via the input unit 94, and performs roughly the following processing based on the data conversion (decryption) algorithm 96.

(I) First, the direction specifying pattern 29 is searched for in the bitmap data (by the method of searching for the direction specifying pattern 29 described above), and is arranged at the four corners in the information recording area 23. The direction specifying pattern 29 is extracted (S22). At this time, the direction specifying pattern 2
9 (position information).

The position of the direction specifying pattern 29 is represented by the position of the center of gravity of the central portion 41. The position of the center of gravity of the center 41 in the bitmap data can be obtained by checking the positions of all the black bits (see FIG. 15) constituting the center 41 and averaging them.

(Ii) Next, the information recording area 23 is analyzed by analyzing the direction specifying patterns 29 arranged at the four corners.
(Inclination) of the information recording area 23 (as described above).
(S23).

(Iii) The obtained information recording area 23
Then, it is determined whether or not the top, bottom, left and right directions are inclined by a predetermined angle (for example, ± 45 °) or more (S24). If the top and bottom left and right directions of the information recording area 23 are inclined by a predetermined angle or more, the rotation processing unit 98 # outputs an instruction to eliminate the inclination of the information recording area 23, and the rotation device 99 records the information with the reading device 92. Relative to the surface 20 (S
25). As a result, the right and left directions of the information recording area 23 are correct on the bitmap data.

Since the rotation of the reading device 92 and the recording surface 20 by the rotation device 99 is performed continuously, the rotation angle is not limited to 90 °, 180 ° or 270 °, and the rotation angle is not required. What is necessary is just to rotate by an arbitrary angle.

(Iv) Thereafter, returning to step S21,
Steps S21 to S24 are repeated. If it is determined that the top and bottom directions of the information recording area 23 are not tilted by a predetermined angle or more (S24), the process proceeds to the next step 26.

That is, the size of one cell is determined by examining the brightness of the cells constituting the directionality specifying pattern 29 arranged at the four corners (S26).

(V) Next, based on the position information of the directionality specifying patterns 29 arranged at the four corners and the predetermined arrangement information, the remaining directionality specifying patterns 29 are extracted (S).
27).

Here, the predetermined arrangement information is, for example, a direction specifying pattern 2 such that a direction specifying pattern 29 appears every 15 vertical cells and every 15 horizontal cells.
9 is the information on the arrangement of 9.

(Vi) Next, based on the position information of each extracted directionality specifying pattern 29, the position of the cell 21 representing the original recording information is determined (S28). Here, it is assumed that the position of the cell 21 representing the original recording information is determined by the method already described with reference to FIG.

(Vii) Next, information recorded in such a cell 21 is read out according to a predetermined mapping (S29).

Then, the output device 93 outputs the output information passed from the output unit 96 of the information decoding device 91 # (S30).

In this way, the digital information recorded on the recording surface 20 of the record carrier as shown in FIG. 1 can be decoded. According to this digital information decryption method, the original recorded information is decrypted after determining the top and bottom directions of the information recording area 23, so that the original recorded information can be correctly decrypted by one decryption process. .

Further, since it is not necessary to perform a rotation process (coordinate conversion process) on the bitmap data, it is possible to easily perform a process of decoding the original recorded information. Accordingly, a memory required for the coordinate conversion process of the bitmap data is not required.

In the flow of FIG. 8, the information recording area 2
3 are extracted (S1).
4) The rotation process (S15) is to be performed later.
In the flow of 1, after searching for the direction specifying patterns 29 at the four corners (S 22), before searching for the remaining direction specifying patterns 29, the top and bottom directions of the information recording area 23 are obtained (S 23), and the rotation is performed. It is determined whether or not to perform (S24). The reason is that, in the flow of FIG. 21, when the rotation is performed, the bitmap data read by the reading device 92 and input again becomes completely different.
This is because, even if the search for the directionality specifying pattern 29 other than the four corners is performed first, the search is completely useless. On the other hand, in the case of the flow of FIG. 8, even if the rotation processing of 90 °, 180 °, or 270 ° is performed after the position information of all the directionality specifying patterns 29 in the information recording area 23 is obtained, it is extremely small. The position information of the directionality specifying pattern 29 after the rotation processing can be calculated by simple coordinate conversion. Rather, all direction-specific patterns 29
If the calculation is performed based on the information obtained from the above, the top and bottom directions of the information recording area 23 can be obtained with higher accuracy.

[0132]

As is apparent from the above description, in the digital information recording method according to the first aspect, the directivity specifying pattern is an asymmetric pattern with respect to the rotation of 90 °, 180 ° and 270 ° in the recording surface. Therefore, the top, bottom, left, and right directions of the information recording area can be indicated by one type of direction specification pattern. Therefore, the procedure for setting and identifying the directionality specifying pattern does not become complicated. In addition, since the directionality specifying pattern indicates the position in the information recording area and also indicates the top, bottom, left and right directions of the information recording area, the area representing the original recording information can be made relatively large. Thus, the information recording area can be effectively used.

When a plurality of the above-mentioned one type of direction specifying pattern is arranged in the information recording area, even if a part of the direction specifying pattern (for example, four corners of the information recording area) is broken, the remaining direction specifying patterns are broken. The pattern can indicate the top, bottom, left and right directions of the information recording area. Therefore, the information indicating the top, bottom, left and right directions of the information recording area is lost as compared with the case where different specific patterns having different shapes and different shades are provided at the four corners of the information recording area to indicate the top, bottom, left and right directions of the information recording area. It becomes difficult.

At the time of reading, first, the direction specific pattern in the information recording area is searched and analyzed to analyze the pattern, so that the top, bottom, left and right of the information recording area can be determined.
Before reading the original recording information of the grid unit, the top, bottom, left and right directions of the information recording area can be identified. Therefore, even if the top and bottom directions of the information recording area are initially incorrect, there is no need to redo the decoding of the recording information in mesh units.

In the digital information recording method according to the second aspect, the direction specifying pattern surrounds a central portion made up of one cell shaded as the mark, and surrounds the central portion in a continuous manner. It has a first annular portion composed of a plurality of cells with light as the mark, and a second annular portion composed of a plurality of cells darkened as the mark, surrounding the center portion in a continuous manner. And, the mesh constituting the first annular portion is 90% centered on the central portion.
The configuration of being connected in an asymmetrical shape with respect to the rotation of 180 °, 180 ° and 270 ° makes it easy to find the direction specific pattern in the information recording area.
In addition, the number of cells constituting the directionality specifying pattern is relatively small. Further, when the same or similar pattern appears in the vicinity as the original recording information, the directionality specifying pattern is unlikely to overlap the pattern. Further, the direction specific pattern is less susceptible to stains during printing and bleeding of ink. Also, the algorithm for finding the direction specific pattern is simplified.

In the digital information decoding method according to the third aspect, the top and bottom left and right directions of the information recording area are obtained,
Since the digital information (original recording information) recorded in an area other than the area occupied by the directionality specifying pattern in the information recording area is read, the original recording information can be correctly read by one decoding process.

In the digital information decoding method according to a fourth aspect, when the direction specifying pattern is the direction specifying pattern according to the second aspect, the position of the center of gravity of the center of the direction specifying pattern and the position of the first annular portion are determined. Since the top and bottom directions of the information recording area are obtained based on the position of the center of gravity, the top and bottom directions of the information recording area can be identified by simple processing.

In the digital information decoding method according to the fifth aspect, since the top and bottom and right and left sides of the information recording area are oriented correctly by performing a rotation process on the bitmap data, the subsequent process of decoding the original recorded information is performed. Can be done easily. Further, the process of reading the two-dimensional pattern recorded on the recording surface by the reading means can be completed only once.

In the digital information decoding method according to the sixth aspect, after the reading means and the recording surface are relatively rotated so that the information recording area is oriented correctly with respect to the reading means, reading is performed again. Therefore, unlike the fifth aspect, there is no need to perform a rotation process (coordinate conversion process) on the bitmap data. Therefore, the process of decoding the original recorded information can be easily performed. Further, the memory required for the bitmap data coordinate conversion process is not required. Further, since the relative rotation between the reading means and the recording surface is performed continuously, the rotation angle can be set arbitrarily.

According to the digital information decoding apparatus of the present invention, digital information recorded by the digital information recording method of the present invention can be decoded.

According to the digital information decoding device of the present invention, digital information recorded by the digital information recording method of the present invention can be decoded.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a two-dimensional pattern recorded on a recording surface by a digital information recording method according to an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating an arrangement of a directionality specifying pattern in FIG. 1;

FIG. 3 is a diagram showing a configuration of a directionality specifying pattern in FIG. 1;

FIG. 4 is a diagram showing an example of a pattern that can be adopted as a direction specifying pattern.

FIG. 5 is a diagram illustrating a block configuration of a digital information recording device according to an embodiment of the present invention.

FIG. 6 is a diagram showing a processing flow for implementing a digital information recording method according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a block configuration of a digital information decryption apparatus according to an embodiment of the present invention.

FIG. 8 is a diagram showing a processing flow for implementing the digital information decoding method according to one embodiment of the present invention.

FIG. 9 is a diagram illustrating a method for searching for a directionality specifying pattern arranged at the upper left corner of the information recording area.

FIG. 10 shows an information recording area of 90 °, 180 °, and 270.
FIG. 9 is a diagram for explaining a method of searching for a directionality specifying pattern arranged at a corner of an information recording area when the information recording area has been rotated by degrees.

11 is a diagram showing a state where the directionality specifying pattern of FIG. 3 overlaps with a pattern having similar characteristics appearing in the vicinity thereof.

FIG. 12 is a diagram illustrating a processing flow for recognizing the directionality specifying pattern in FIG. 3;

FIG. 13 shows a first pattern when recognizing the specific pattern in FIG.
It is a figure which shows typically the method of making a round around the boundary of an annular part and a 2nd annular part by the left method, and confirming a 2nd annular part.

FIG. 14 is a diagram schematically showing a state when a closed black dot area is circled by the left method in FIG. 13;

15 is a diagram illustrating an example of bitmap data obtained by reading the directionality specifying pattern of FIG. 3 by a reading device.

FIG. 16 is a diagram showing a central part of the direction specifying pattern shown in FIG.
It is a figure which represents the position of the center of gravity of an annular part typically.

FIG. 17 is a diagram schematically showing a state in which the inclination of the directionality specifying pattern of FIG. 3 is within an allowable range of ± 45 ° on bitmap data.

FIG. 18 is a diagram showing a block configuration of a digital information decryption apparatus according to another embodiment of the present invention.

FIG. 19 is a diagram illustrating a state in which a camera is rotated by a rotation device.

FIG. 20 is a diagram showing a state in which a record carrier is rotated by a rotating device.

FIG. 21 is a diagram showing a processing flow for implementing the digital information decoding method according to one embodiment of the present invention.

FIG. 22 is a diagram exemplifying a two-dimensional pattern recorded on a recording surface by a digital information recording method proposed earlier by the present applicant.

FIG. 23 is a diagram schematically showing an arrangement of a specific pattern in FIG. 22;

24 is a diagram showing a configuration of a specific pattern in FIG.

FIG. 25 is a diagram showing a state where the specific pattern of FIG. 24 overlaps the same pattern appearing in the vicinity thereof.

FIG. 26 is a diagram for explaining a mapping method for associating bit information to be originally recorded with cells in an area other than the area where a specific pattern is to be arranged in the information recording area;

FIG. 27 is a diagram illustrating a method of calculating the position of an arbitrary cell in the information recording area based on the positions of four specific patterns.

FIG. 28 is a diagram illustrating an example in which specific patterns arranged at four corners of an information recording area are different from the remaining specific patterns.

FIG. 29 is a diagram showing an example in which an arrow-shaped pattern representing left and right sides of the top and bottom is recorded in a margin between specific patterns in the information recording area.

FIG. 30 is a diagram showing an example in which an arrow-shaped pattern indicating the top, bottom, left and right is recorded in a segment at the upper left corner constituting an information recording area.

[Explanation of symbols]

 Reference Signs List 20 recording surface 21 area in which original information is to be recorded 29 directionality specifying pattern 41 central part 42 first annular part 43 second annular part

Claims (8)

[Claims] An information recording area provided in a planar recording surface virtually sets a matrix of matrixes corresponding to bits, and optically sets a matrix corresponding to digital information to be recorded in each of the above-mentioned squares. A digital information recording method for recording a digital information to be recorded as a two-dimensional pattern by providing a recognizable mark, and indicating a position in the information recording area and a top, bottom, right and left direction of the information recording area. As described above, in the information recording area,
A plurality of squares connected in a specific shape are provided with a direction specific pattern in which the marks are asymmetrically applied to rotations of 90 °, 180 °, and 270 ° in the recording surface. Digital information recording method. 2. The digital information recording method according to claim 1, wherein the directivity specifying pattern is formed by connecting a central portion made up of one square with the mark as the mark, and a periphery of the central portion. A first annular portion formed of a plurality of cells surrounded by light as the mark, and a second annular portion formed of a plurality of cells surrounded by the surrounding area and shaded as the mark. And the meshes constituting the first annular portion are connected to each other in an asymmetric shape with respect to rotation of 90 °, 180 °, and 270 ° around the central portion. Digital information recording method. 3. A digital information decoding method for decoding recording information recorded by the digital information recording method according to claim 1 or 2, wherein the digital information decoding method searches the information recording area for the directionality specifying pattern. In addition to obtaining the position, the brightness of the squares forming the direction specifying pattern is checked to determine the top and bottom left and right directions of the information recording area. A digital information decoding method comprising: reading digital information recorded in an area other than an area occupied by the directionality specifying pattern in the information recording area based on a position. 4. The information decoding method according to claim 3, wherein when the direction specifying pattern is the direction specifying pattern according to claim 2, a center of gravity of the center of the direction specifying pattern; A digital information decoding method comprising: calculating a center of gravity of a first annular portion; and determining a top, bottom, left and right direction of an information recording area based on a center of gravity of a center portion and a center of gravity of the first annular portion. 5. A digital information decoding method for decoding recording information recorded by the digital information recording method according to claim 1 or 2, wherein a two-dimensional pattern recorded on the recording surface is read by a reading means. After creating bitmap data representing the two-dimensional pattern, searching for the directional specific pattern in the bitmap data to determine its position, and examining the brightness of the cells constituting the directional specific pattern The top and bottom directions of the information recording area are obtained by using the obtained top and bottom directions of the information recording area.
A rotation process is performed on the bitmap data so that the information recording region appearing in the bitmap data is oriented correctly. Based on a position of the directionality specifying pattern after the rotation process, the information recording region is Reading digital information recorded in an area other than the area occupied by the directionality specifying pattern. 6. A digital information decoding method for decoding recording information recorded by the digital information recording method according to claim 1 or 2, wherein a two-dimensional pattern recorded on the recording surface is read by a reading means. After creating bitmap data representing the two-dimensional pattern, searching for the directional specific pattern in the bitmap data to determine its position, and examining the brightness of the cells constituting the directional specific pattern The orientation of the information recording area is obtained from the top and bottom and the orientation of the information recording area. Are relatively rotated, the two-dimensional pattern recorded on the recording surface is read again by the reading means, and the two-dimensional pattern is displayed. Create bitmap data, search for the direction specifying pattern in the bitmap data to find its position, and, based on the position of the direction specifying pattern, determine whether the direction specifying pattern in the information recording area is A digital information decoding method comprising reading digital information recorded in an area other than an occupied area. 7. A digital information decryption device for decrypting digital information recorded by the digital information recording method according to claim 2, comprising: reading a two-dimensional pattern recorded on the recording surface;
Reading means for outputting bitmap data representing the two-dimensional pattern; searching means for searching for the position of the directionality specifying pattern in the bitmap data to determine the position thereof; and forming the central portion of the directionality specifying pattern. The center of gravity of the dot to be formed and the center of gravity of the dot forming the first annular portion are calculated, and the center of gravity of the center and the center of gravity of the first annular portion are compared. Tilt detecting means for detecting the tilt of the information recording area; and 0 °, 90 ° with respect to the bitmap data based on the tilt of the information recording area detected by the tilt detecting means.
Of the rotation processes of °, 180 °, or 270 °, a rotation process in which the inclination of the information recording area in the bitmap data after the rotation process is within ± 45 ° is selected, and the selected rotation process is performed. Bitmap data rotating means for applying to the bitmap data, and recording in the area other than the area occupied by the direction specific pattern in the information recording area after the rotation processing, based on the position of the direction specific pattern. A digital information decryption device comprising: information decryption means for reproducing the digital information reproduced; and output means for outputting the digital information reproduced by the information decryption means. 8. A digital information decryption device for decrypting digital information recorded by the information recording method according to claim 2, comprising: reading a two-dimensional pattern recorded on the recording surface;
Reading means for outputting bitmap data representing the two-dimensional pattern; searching means for searching for the position of the directionality specifying pattern in the bitmap data to determine the position thereof; and forming the central portion of the directionality specifying pattern. The center of gravity of the dot to be read and the center of gravity of the dot forming the first annular portion are calculated, and the center of gravity of the center and the center of gravity of the first annular portion are compared. An inclination detecting means for detecting a relative inclination in the rotation direction between the area and the area, and the reading means and the recording surface are relatively positioned on the basis of the inclination detected by the inclination detecting means so as to eliminate the inclination. Mechanical rotating means for rotating, based on the position of the direction specific pattern, digital information recorded in an area of the information recording area other than the area occupied by the direction specific pattern A digital information decoding device comprising: information decoding means for reproducing information; and output means for outputting digital information reproduced by the information decoding means.