JP4765894B2 - Image generating apparatus, information reading apparatus, and recording medium - Google Patents

Description

  The present invention relates to an image generation device, an information reading device, and a recording medium.

Conventional technology is known in which position information is embedded on a recording medium such as output paper, a partial image on the recording medium is read by a pen-type reading device, and position information is acquired from the partial image to obtain a locus of the pen-type reading device. (For example, see Patent Documents 1 to 6).
Patent Document 1 discloses the following technique. A product having a coding pattern with a plurality of marks, each of the marks representing one of at least two different values. The encoding pattern also includes a plurality of reference positions, and each of the plurality of marks is associated with one reference position. The value of each mark is determined by its position relative to its reference position.
Patent Document 2 discloses the following technique. The document is watermarked with a maze pattern and the encoded position information is determined therefrom. The sequence of images is captured by a camera placed on the pen. The nib path is determined by decoding the associated maze pattern and matching the captured image with the document image.

Patent Document 3 discloses the following technique. A first two-dimensional code formed in a printed document in a two-dimensional code formed by arranging a plurality of two-dimensional codes having document unique information and position information of the document in a part or all of the printed document on which the document is printed. And a second two-dimensional code formed in a predetermined area of the print document and having a different form from the first two-dimensional code.
Patent Document 4 discloses the following technique. An optically readable dot code recorded on a recording medium such as paper is formed by arranging a plurality of blocks adjacent to each other. Each block has an unmodulated area including a marker 310 for recognizing the block, and each bit value of data subjected to modulation processing so as to be structurally distinguishable from the marker is arranged in dots corresponding to the value. And a data area as a modulation area including a data dot pattern composed of a plurality of dots. Further, a block address pattern for indicating a block address is further arranged in the non-modulation area.

  Patent Document 5 discloses the following technique. The image processing apparatus detects a plurality of digital codes embedded in the read image, and extracts the additional information of the document image by combining the plurality of digital codes based on the address information recorded inside the digital code. . The image processing apparatus detects address information and digital data from the detected digital code. When the address information is detected, the image processing apparatus registers the detected address information and digital code in the code information registration unit. And when the address information is not detected by the information detecting means, the address confirmed digital code registered in the code information registering means is compared with the address undecided digital code in which the address is not detected. Address determination means for determining the address of the undefined digital code.

  Patent Document 6 discloses the following technique. Form multiple copies of the encoding that are essentially the same, and combine machine-recognizable spatial synchronization indicators with the print positions in each of the copies of the encoding to provide multiple instances of spatial synchronization of the encoding To do. These cases are written in a spatially periodic center lattice on the recording medium according to the layout rule. The layout rule formats each encoding case spatially and uniformly, while being tiled on the recording medium in at least one direction according to a fixed length tile dividing vector, and the tiled data pattern is recorded on the recording medium. An encoding case is mapped to each two-dimensional non-overlapping data block recorded in the above.

Japanese translation of PCT publication No. 2003-511761 JP 2005-235185 A JP 2006-085679 A JP-A-10-187910 JP 2004-228739 A JP-A-9-185669

  An object of the present invention is to provide an image generation apparatus that generates an image in which information of an arbitrary amount of information is recorded using an image pattern that represents encoded information.

In order to achieve the above object, the invention according to claim 1
Information acquisition means for acquiring recording information recorded on the recording medium;
A position code image pattern representing a position information unique to a position on the recording medium arranged in a certain section, and an information code image pattern representing the record information arranged in the section, And an image generation unit that generates an image in which specific recording information is described by the information code arranged in the section.
The invention according to claim 2
In the image generated by the image generation means, section identification information is set according to the position information of the section represented by the position code and the number of the sections describing the specific recording information, and the same The information code representing the same part in the specific recording information is arranged in the section to which the section identification information is assigned.
The invention according to claim 3
In the image generated by the image generation means, a specific code for specifying the number and arrangement of the sections in which the entire specific recording information is described is further arranged.
The invention according to claim 4
An image generation unit for generating an image in which predetermined information is recorded by two-dimensionally arranging a code block in which a position code representing a position on a recording medium and an information code representing recording information are described in an image pattern;
An information dividing unit that divides the recording information into a plurality of pieces of partial information according to the number of code blocks necessary for recording the recording information;
A code block arrangement unit that arranges the code block in which the partial information is described by the information code is arranged at a position represented by the position code.
The invention according to claim 5
For each code block group including the number of code blocks necessary for recording the recording information, the code block arrangement unit determines the position of each code block in the code block group and the number of divisions of the recording information. An index set accordingly is assigned, and the code block in which the same partial information is described is arranged at the position of the code block to which the same index is assigned.
The invention according to claim 6
The code block includes a specific code that specifies the number and arrangement of the code blocks included in the code block group.
The invention according to claim 7 provides:
Reading means for reading the image of the code pattern printed on the surface of the recording medium;
Code detecting means for detecting a position code representing a position and an information code representing recorded information from the image read by the reading means;
Section identifying means for identifying a section in which the information code is arranged based on position information obtained from the position code detected by the code detecting means, and generating identification information of the section;
An information acquisition unit configured to acquire a code string arranged in the section identified by the section identification unit, synthesize the code string based on the identification information, and acquire the recording information; Realized as an information reader.
The invention according to claim 8 provides:
The section identifying means identifies a region composed of a plurality of the sections in which a piece of the recording information is divided and recorded.
The invention according to claim 9 is:
The section identifying means identifies the order of the code strings arranged in the section with respect to the plurality of sections included in the region.
The invention according to claim 10 is:
A recording medium having an image pattern drawn on its surface,
An image pattern of a position code that is arranged in a certain section and represents position information unique to the position on the recording medium;
Arranged in the section formed by the image pattern of the position code, the image pattern of the information code representing the recording information is drawn,
A group of the recorded information is described by the information codes arranged in the plurality of sections, and is realized as a recording medium.
The invention according to claim 11 is:
A plurality of areas composed of a plurality of the sections in which a group of the recording information is described are formed, and the information code representing the same portion in the recording information is arranged at a corresponding position in each area. To do.
The invention according to claim 12
A recording medium having an image pattern drawn on its surface,
One or a plurality of areas in which a plurality of code blocks including a position code representing a position on the recording medium and an information code representing recording information are arranged are formed,
It is realized as a recording medium characterized in that a group of the recording information is described by a plurality of the code blocks arranged in a single area.

According to the first aspect of the present invention, it is possible to generate an image in which information of an arbitrary information amount is described by using information codes arranged in a plurality of sections.
According to the second aspect of the present invention, it is possible to provide redundancy to information recorded in an image and reliably acquire information from the image.
According to the invention of claim 3, the range in which the specific record information is described can be easily recognized, and efficient information acquisition is possible.
According to the fourth aspect of the present invention, an image in which information of an arbitrary amount of information is described can be generated by using a plurality of code blocks.
According to the fifth aspect of the present invention, it is possible to provide redundancy to information recorded in an image and to reliably acquire information from the image.
According to the invention of claim 6, the range in which the specific record information is described can be easily recognized, and efficient information acquisition is possible.
According to the invention which concerns on Claim 7, information can be acquired from the image in which the information was described using the information code arrange | positioned at several divisions.
According to the eighth aspect of the invention, it is possible to reliably acquire information by recognizing a range in which a group of recorded information is described.
According to the ninth aspect of the invention, it is possible to reliably acquire the recording information described by being divided into a plurality of sections.
According to the invention which concerns on Claim 10, the information of arbitrary information amounts can be recorded on an image pattern by using the information code arrange | positioned at several divisions.
According to the eleventh aspect of the invention, it is possible to provide redundancy to information recorded in an image and to reliably acquire information from the image.
According to the twelfth aspect of the present invention, information of an arbitrary amount of information can be recorded as an image pattern by using a plurality of code blocks.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the accompanying drawings.
First, the configuration of a code pattern image used in the present embodiment will be described, and then a code pattern image generation device and an information decoding device using the code pattern image will be described.

<Unit code pattern>
FIG. 1 is a diagram illustrating an example of a unit code pattern of a code pattern image used in the present embodiment.
In the example shown in the figure, dots are arranged by selecting three locations from a total of nine locations where dots can be arranged in three places in the vertical direction (hereinafter referred to as 3 × 3 places). In this case, there are 84 dot arrangement combinations of the unit code pattern (84 = ₉ C ₃ ) (where _m C _n = m! / {(Mn)! × n!}). When recording at 600 dpi, one dot size (square size) in FIG. 1 is 2 pixels in the vertical direction and 2 pixels in the horizontal direction (hereinafter referred to as 2 × 2 pixels), and the calculation is 84.6 μm × 84. It becomes a 6 μm rectangle (however, the recorded toner image has a dot shape of about φ100 μm due to the influence of the xerographic process). Therefore, the size of the unit code pattern is 0.5076 mm × 0.5076 mm.

Of the 84 types of unit code patterns, 64 types of unit code patterns (64 = 2 ⁶ = 6 bits) are used as information embedding codes (hereinafter referred to as information codes). The remaining 20 types of unit code patterns are used for detection of code blocks (described later) and for synchronous codes for detecting rotation angles.
FIG. 2 is a diagram showing 84 dot arrangements that the unit code pattern of FIG. 1 can take, and FIG. 3 is a diagram showing examples (5 sets) of four types of unit code patterns that can be used as synchronization codes. In order to simplify the display, spaces between dots are omitted.

  As the synchronization code, there are four patterns for detecting the rotation angle of the code block every 90 degrees, but by using 20 patterns, five sets of synchronization codes can be created. The four unit code patterns used for the synchronization code are selected so as to be 90-degree rotationally symmetrical patterns. That is, if one of the four types of unit code patterns is embedded as a synchronization code at the time of image generation, the rotation angle of the code block (depending on which angle of the four types of unit code patterns is detected at the time of decoding) (Which direction of 0/90/180/270 degrees of the code block synchronized on the two-dimensional array is oriented) can be determined and corrected.

Note that the unit code pattern is not limited to the method of arranging dots at three of nine positions as shown in FIG. 3, and may be any number as long as it is smaller than nine. For example, if the dot is arranged at 4 out of 9 places, there are 126 combinations of the dot arrangement (126 = ₉ C ₄ ). Further, the number of places where dots can be arranged is not limited to nine (3 × 3), but may be other numbers, for example, four (2 × 2) or 16 (4 × 4).

<Code block>
FIG. 4 is a diagram illustrating an example of a code block used in the present embodiment.
The code block shown in FIG. 4 is configured by arranging 5 × 5 unit code patterns shown in FIG. The synchronization code shown in FIG. 3 is arranged at the upper left position of the code block. That is, one of the synchronization codes shown in FIGS. 3A to 3E is selected, and one selected from the four unit code patterns included in the selected synchronization code is arranged at the upper left of the code block. The

In FIG. 4, position codes are arranged using four unit code patterns adjacent to the right side of the synchronization code and four unit code patterns adjacent to the lower side. The position code is a unit code pattern representing position information unique to the position on the recording medium on which the code pattern image is formed. In the present embodiment, an orthogonal coordinate (XY coordinate) is assumed on the surface of the recording medium, and the position is represented by the coordinate value. Therefore, the position code adjacent to the right side of the synchronization code is a position code obtained by encoding position information unique to the position in the X direction on the recording medium, and the position code adjacent to the lower side is the position in the Y direction on the recording medium. A position code obtained by encoding unique position information is arranged. Since the position codes in the X direction and the Y direction each use four unit code patterns, each can store information of 24 bits (6 bits × 4 pieces). Note that it is possible to use only 16 types of patterns as position codes without using 64 types (64 = 2 ⁶ ) patterns for embedding information. In this case, since the information amount per unit code pattern is 4 bits (16 = 2 ⁴ ), the position code is 16 bits (4 bits × 4 pieces) of information amount.

An M sequence (Maximum Length Code) can be used as an example of the position code. For example, if a 12th-order M sequence is used, the sequence length of the M sequence is 4095 (= 2 ¹² −1). When 16 types of patterns are selected as the unit code pattern of the position code, 4-bit information can be stored in each unit code pattern. Therefore, since there are four unit code patterns of the position code in one code block, 16 bits ( 4 bits × 4 pieces of information can be stored. Therefore, the M sequence having a sequence length of 4095 can be divided and stored in 255 (= 4095 ÷ 16) code blocks. Since the size of one side of one code block is 2.538 mm (= 0.5076 mm / unit code pattern × 5), the length of 255 consecutive code blocks is 647.19 mm. That is, a length of 647.19 mm can be encoded. In terms of paper size, it is possible to encode up to A2 size (420 × 594 mm) paper.

  Here, an example in which the position is encoded with one M sequence has been shown, but the number of positions that can be encoded can be further increased by connecting a plurality of M sequences. For example, even when an 11th-order M-sequence is used, A0 size paper can be encoded by connecting four of them.

  In the remaining area of the code block, an information code capable of describing arbitrary recording information is arranged. Since 16 unit code patterns (4 × 4) can be arranged in this area, 96 bits (6 bits / unit code pattern × 16) of recording information can be recorded. Since the unit code pattern of the present embodiment is a multi-level code, errors that occur during reading and the like also occur in units of the unit code pattern. Therefore, it is desirable that the error correction code be a system that can perform error correction in units of blocks. If an RS code (Reed-Solomon Code), which is a known block error correction code system, is used, the block length of the RS code can be set to 6 bits, which is the information amount of the unit code pattern. In this case, the code length of the RS code is 16 blocks (= 96 bits / 6 bits / block). For example, if the correction capability of 3 blocks is provided, the information code length of the RS code is 10 blocks (= 16 blocks− 3 blocks × 2). In this case, as the recording information, information of 60 bits (= 6 bits / block × 10 blocks) can be embedded in the information code area.

  On the recording medium, the above-described code blocks are arranged side by side in the X direction and the Y direction. Therefore, when viewed from the whole recording medium, the sequence of position codes representing the positions in the X direction and the Y direction are arranged in a lattice pattern with a constant interval (four unit code patterns). A certain region having a width corresponding to 16 unit code patterns (4 × 4) is formed surrounded by the sequence of position codes. The information code area of the code block described above corresponds to an area formed by being surrounded by this position code (hereinafter, this area is referred to as an information code area).

<Code pattern image generation apparatus>
Next, a code pattern image generation apparatus that generates the above-described code pattern image will be described.
FIG. 5 is a diagram illustrating a configuration of the code pattern image generation apparatus according to the present embodiment.
Referring to FIG. 5, the code pattern image generation apparatus according to the present embodiment roughly includes a code block generation unit 100 that generates the above-described code block, and an output image generation unit 200 that forms the generated code block on a recording medium. With. Among these, the function of the code block generation unit 100 can be grasped by dividing it into synchronous code arrangement means, position code arrangement means, and information code arrangement means. As shown in FIG. 5, the code block generation unit 100 includes a synchronization code selection unit 111 and a code block arrangement unit 141 as synchronization code arrangement means. In addition, an M-sequence acquisition unit 121, an M-sequence division unit 122, and a code block arrangement unit 141 are provided as position code arrangement means. In addition, an information acquisition unit 131, an information division unit 132, an RS encoding unit 133, and a code block arrangement unit 141 are provided as information code arrangement means. Each of these functions is realized by a computer-controlled CPU (Central Processing Unit) of a computer that implements the code pattern image generation device and a storage device such as a main memory or a magnetic disk device.

As described above, recording information of up to 60 bits can be recorded in one information code area (that is, per code pattern). In the present embodiment, a method of recording recording information of 60 bits or more using this code pattern is proposed.
As described with reference to FIG. 1, when a code block is configured with a unit code pattern of ₉ C ₃ , five sets of synchronous codes can be used. Therefore, as shown in FIG. 6, set numbers are assigned to these five sets of synchronization codes. Then, the number of divisions for dividing information and the amount of information that can be recorded with the information code are defined and associated with the set number of the synchronization code. For example, when the synchronous code set No. 0 is selected, the information is not divided (division number 1). The information amount of the record information that can be recorded with the information code is 60 bits. In addition, when the set number 2 of the synchronization code is selected, if it is defined that 18 information code areas can be used, information of 135 bytes (60 bits × 18/8) is recorded with the information code. can do. In the correspondence table shown in FIG. 6, the number of divisions in the X direction and the number of divisions in the Y direction representing the arrangement of information code areas (or code blocks) corresponding to the number of divisions are registered. The correspondence table of FIG. 6 is held in a storage device such as a magnetic disk device.

  When the number of divisions of the recording information is determined by the information dividing unit 132 as will be described later, the synchronization code selection unit 111 shown in FIG. 5 refers to the correspondence table of FIG. 6 and determines the synchronization code corresponding to the number of divisions. Select the synchronization code to use from the set.

  The M sequence acquisition unit 121 acquires an M sequence that can be used for position information according to the size of the recording medium. In principle, the position information can be encoded by obtaining the required M-sequence order from the length to be encoded (the length of one side of the recording medium) and dynamically generating the M-sequence. it can. However, when the length to be encoded is determined in advance as in the present embodiment, the M sequence is stored in a predetermined storage device, and an appropriate M sequence is stored from the storage device when the code pattern image is generated. It is good also as a structure to read.

  The M sequence division unit 122 divides the M sequence obtained by the M sequence acquisition unit 121 into blocks of every 4 bits, which is the number of unit code pattern bits of the position code, in order to assign the position code of each code block. FIG. 7 is a diagram showing a state in which the M sequence is divided into blocks and assigned to each position code as position information. Although FIG. 7 shows only the assignment of position information in the X direction, it goes without saying that the position information is assigned in the Y direction as well.

  The information acquisition unit 131 acquires recording information to be recorded on the recording medium using a code pattern image. The recorded information may be acquired by reading out information stored in a predetermined storage device in advance, or may be acquired by receiving it from an external device via a network. Moreover, you may receive and acquire the input operation by the user performed using input devices, such as a keyboard.

  The information dividing unit 132 calculates the number of divisions of the recording information based on the information amount of the recording information acquired by the information acquisition unit 131 and the information amount that can record one information code area (or code block). Then, the calculated number of divisions is notified to the synchronization code selection unit 111, and information on the set number of the synchronization code to be used and the number of divisions in the X direction and the Y direction is acquired with reference to the correspondence table shown in FIG. . For example, when 32-byte information is acquired as recording information, set number 1 that can record up to 45 bytes is selected, and when 256-byte information is acquired, set number 3 that can record up to 525 bytes is selected. .

  The information dividing unit 132 divides the recording information into the number of divisions defined by the selected set number. For example, when the set number 1 is selected, the recording information is divided into 6 parts by 60 bits. Further, in order to perform RS encoding, each of the divided recording information is divided for each block length (6 bits in this embodiment) of the RS code. That is, the previously divided recording information of 60 bits is divided into 10 bit blocks each having a bit length of 6 bits.

  The RS encoding unit 133 performs RS encoding processing on the bit block divided by the information dividing unit 132, and adds a redundant block for error correction. If an RS code capable of correcting an error of 3 blocks is used, the code length is 16 blocks.

  The code block arrangement unit 141 is a virtual code corresponding to the recording medium, obtained by the above-described functions, the synchronization code, the position code expressed as an M sequence and divided into blocks, and the RS encoded information code. A two-dimensional code plane is generated by arranging on a two-dimensional plane.

  As illustrated in FIG. 5, the output image generation unit 200 includes a bit pattern holding unit 201, a pattern selection unit 202, and an image output unit 203. Among these, the bit pattern holding unit 201 is realized by a storage device such as a magnetic disk device. Similarly to the functions of the code block generation unit 100, the pattern selection unit 202 and the image output unit 203 are realized by a program-controlled CPU and a storage device such as a main memory or a magnetic disk device.

  The bit pattern holding unit 201 holds a pattern image of a unit code pattern. The pattern selection unit 202 selects a pattern image of a unit code pattern corresponding to the code plane generated by the code block arrangement unit 141 and acquires it from the bit pattern holding unit 201. The image output unit 203 forms and outputs an image in which the pattern image selected by the pattern selection unit 202 is arranged in correspondence with the code plane generated by the code block arrangement unit 141.

<Division and coding processing of recorded information>
Here, the recording information dividing process performed by the information dividing unit 132 and the RS encoding process performed by the RS encoding unit 133 will be described in more detail.
FIG. 8 is a diagram for explaining the contents of recording information division and encoding processing. Here, an example in which 32-byte recording information is input will be described.
When recording information is described by an information code, 2 bytes (16 bits) indicating the information amount are always included in the recording information stored in the head code block so that the information amount can be easily recognized at the time of detection. This area is added, and a 2-byte error detection code (such as CRC) is always added to the end of the data of the recorded information. Therefore, the recording information is 32 bytes (256 bits), but there is additional information of 4 bytes (32 bits), so that 36 bytes (288 bits) are required as a whole.

  First, the information dividing unit 132 shown in FIG. 5 calculates the necessary number of divisions. Since 60-bit information can be stored in one code block, 5 code blocks are required to store 288-bit information. If the number of divisions is defined as shown in the correspondence table of FIG. 6, it is understood that the set number 1 may be selected as the synchronization code. Therefore, the number of divisions is 6 from the correspondence table.

  Next, the information dividing unit 132 divides the recording information into six recording information blocks. Since 2 bytes (16 bits) indicating the total amount of information is added to the head recording information block, 44 bits of information are stored. 60-bit information is stored in the second to fourth recording information blocks. The last 32-bit information is stored in the fifth recording information block. In this way, 256-bit information is divided into 44 bits + 60 bits × 3 + 32 bits and stored.

  Also, a 16-bit CRC (Cyclic Redundancy Check) code is added to the end of the additional data in the fifth recording information block. The CRC code is a code according to a known method for detecting a decoding error of information at the time of detection. Finally, dummy bits, for example, bits whose bit values are all 0 are added to the remaining area after storing these pieces of information.

  The RS encoding unit 133 shown in FIG. 5 performs RS code processing on each recording information block divided as described above. As described above, assuming that the block length of the RS code is 6 bits and the error correction of 3 blocks is possible, 6 blocks (= 36 bits) of redundant blocks are generated by the RS encoder 133. A 96-bit encoded recording information block to which 36 bits of redundant bits generated by the RS encoding process are added is passed to the code block arrangement unit 141 as an information code.

<Information index>
As described above, the code block arrangement unit 141 arranges a code block including a synchronization code, a position code, and an information code on a two-dimensional plane corresponding to the recording medium. At this time, the position of the position code is naturally specified by the position information represented by itself. Further, as shown in FIG. 4, since the synchronization code is arranged at the intersection of the position code in the X direction and the position code in the Y direction, the position is also specified. On the other hand, since the recording information is arbitrary information and is divided and arranged in a plurality of information blocks, an information code corresponding to a piece of recording information (that is, the entire recording information acquired by the information acquisition unit 131). The position must be specified by a certain method.
Then, next, the information index for specifying the position of each information code when the code block arrangement unit 141 arranges the information code will be described.

  The information index is code block identification information calculated from an M sequence used as position information. When viewed as an arrangement of unit code patterns, the code plane is composed of a position code and a synchronization code that are arranged in a lattice to form a certain section, and an information code that is arranged in this section. Therefore, the information index can be grasped as section identification information for specifying a position (section) where the information code is to be arranged.

The p-order M sequence (sequence length 2 ^p −1) has a property that when p consecutive bit strings are extracted from the M sequence, the p sequence does not appear in other parts of the same M sequence. Therefore, when 12 consecutive bit strings are extracted from the 12th order M sequence (sequence length 2 ¹² -1 = 4095), the 12 sequences have uniqueness that does not appear elsewhere in the same M sequence. Yes. Therefore, a method for generating an information index using the M sequence will be described.

9A and 9B are diagrams for explaining an information index generation method.
As shown in FIG. 9-1 (a), numbers starting from 1 (referred to as block numbers) are allocated to 12 consecutive bit strings in the 12th order M-sequence while shifting one bit at a time from the top. . At this time, it is guaranteed that there are no different block numbers having the same bit string. When this number is viewed on the code pattern arranged as described with reference to FIG. 7, it is arranged as shown in FIG.

Next, for each block number,
(Block number-1) / (code block width-1)
When the number obtained by rounding down the decimal part is calculated, a value as shown in FIG. 9-1 (c) is obtained (in the figure, only one same value is shown for simplicity). This value is called a code block index. The code block index is a number in which the value in the X direction increases by 1 when the code block at the upper left is number 0 and moves to the code block in the right direction, and the value in the Y direction increases by 1 when moved to the code block in the lower direction. is there.

next,
(Code block index number) mod (number of divisions in the X or Y direction)
Is calculated, periodic numbers can be obtained in the X and Y directions as shown in FIG. 9-2 (d). This number is called the X direction division index for the X direction and the Y direction division index for the Y direction. By this X direction division number and Y direction division number, a range (hereinafter referred to as a unit information area) in which a piece of recording information (the entire recording information acquired by the information acquisition unit 131) is recorded is specified. Become. In FIG. 9-2 (d), each area surrounded by a thick line is a unit information area.

The number of divisions in the above equation is the number of divisions in the X direction and the Y direction shown in the correspondence table of FIG. 6. In this embodiment, the number of divisions is 6, the number of X direction divisions is 3, and the number of Y direction divisions is 2. Therefore, when obtaining the X direction division index number,
(Code block index number) mod 3
When calculating the Y direction division index number,
(Code block index number) mod 2
Should be calculated. With the above calculation, the X-direction division index and the Y-direction division index shown in FIG. 9-2 (d) can be obtained.

  Finally, an information index shown in FIG. 9-2 (e) is generated from the X direction division index and the Y direction division index. This can be obtained, for example, by referring to a correspondence table that defines the correspondence relationship between the values of the X-direction division index and the Y-direction division index and the information index as shown in FIG. This correspondence table is held in a storage device such as a magnetic disk device.

Based on the information index generated as described above, the code block arrangement unit 141 is a section formed by position codes of the recording information blocks divided by the information dividing unit 132 and RS-coded by the RS coding unit 133 To place.
FIG. 11 is a diagram showing how recording information blocks are arranged based on an information index.
As shown in FIGS. 9-2 (d) and (e), there are a plurality of unit information areas in which a piece of recording information is recorded on the code plane. And the same information index is provided to the section at the same position in each unit information area included in each unit information area. Therefore, as shown in FIG. 11, the redundancy of the recording information can be increased by arranging the same recording information block in the section to which the same information index is assigned.

<Another example of a method for specifying the number of divisions of recording information>
In the present embodiment described above, information on the number of divisions of recorded information is associated with the type of synchronization code. However, the method for setting the information on the number of divisions of the recording information is not limited to this, and other methods can be used. For example, if data (Set #) indicating the number of divisions of recording information is embedded in each of the divided recording information blocks, by reading this data, the recording information can be recorded without using a plurality of types of synchronization codes. The number of divisions can be recognized. In this case, the synchronization code is a constant synchronization code regardless of the number of divisions. Then, the number of divisions of the recording information can be obtained by inspecting the contents of the recording information block.

FIG. 12 is a diagram illustrating a data configuration example when data indicating the number of divisions of recording information is inserted into the recording information block.
In the example of FIG. 12, data indicating the number of divisions of the record information is inserted into the record information block in the “Set #” portion after the division. In the case of this method, the number of bits required for the portion “Set #” in FIG. 12 differs depending on the number of divisions defined. However, if there are about five types as in the above example, about 3 bits is sufficient.

<Another example of information index generation method>
Moreover, in this Embodiment mentioned above, the information index was produced | generated using the value of the position code. However, the information index generation method is not limited to this. For example, the information index may be expressed by increasing the types of unit code patterns used as position codes and using them separately.

FIG. 13 is a diagram illustrating an example of an information index expressed by the type of position code.
As described above, 64 types of unit code patterns can be used as position codes, but only 16 types are used in this embodiment. Assuming that the position code can be composed of 16 types of unit code patterns, the 64 types of unit code patterns can be divided into four groups, and the position codes can be configured independently for each group. Then, by identifying which of the four groups the unit code pattern belongs to which position code is encoded, it is possible to determine the four types of division numbers. Since up to four types of pattern groups can be selected in both the X direction and the Y direction, up to 16 divisions can be handled.

<Decoding process of recording information and position information>
Next, a process for reading information from the code pattern image formed on the recording medium as described above will be described.
The information decoding device optically reads a code pattern image formed on a recording medium, detects a code, and reads information. The information decoding apparatus is realized by a pen-type reading device (electronic pen: details will be described later), a scanner, or the like.

FIG. 14 is a diagram illustrating a configuration of the information decoding device.
Referring to FIG. 14, the information decoding apparatus according to the present embodiment includes an image input unit 301, a noise removal unit 302, a dot pattern detection unit 303, a synchronization unit 304, a unit code pattern boundary detection unit 305, and a synchronization code. A detection unit 306, an information code detection unit 307, an RS code decoding unit 308, a position code detection unit 309, a position code decoding unit 310, and a recorded information restoration unit 311 are provided. Each of these functions is realized by a control circuit of the information decoding device and a storage device such as a memory.

The image input unit 301 optically reads a code pattern image formed on a recording medium by an image sensor such as a CCD or a CMOS, and sends the read image to the noise removing unit 302.
The noise removing unit 302 performs processing for removing noise (image sensor sensitivity variation, noise generated by an electronic circuit, etc.) included in the image received from the image input unit 301. The type of noise removal processing should match the characteristics of the imaging system, but sharpening processing such as blurring processing and unsharp masking can be applied. Moreover, a known removal method can be used as a specific removal method.

  The dot pattern detection unit 303 detects a dot pattern (a position of the dot image) from the image from which noise has been removed. Specifically, first, the dot pattern portion and the background image portion of the image are separated by binarization processing. Then, the position of the dot pattern is detected from each binarized image position. Since there are cases where a lot of noise components are included in the binarized image, it is necessary to combine filter processing for determining the dot pattern based on the area and shape of the binarized image.

  The synchronization unit 304 refers to the position of the detected dot pattern and synchronizes the dot pattern on the two-dimensional array. Here, “synchronize” means that the position where the dot pattern is present is replaced with 1 on the two-dimensional array, the position where there is no dot pattern is replaced with 0, etc., and the dot pattern detected as an image is converted into digital data of the two-dimensional array. This is a replacement process. Details of the synchronization processing will be described later.

The unit code pattern boundary detection unit 305 detects the boundary of the unit code pattern constituting the code block from the dot pattern developed on the two-dimensional array. On the two-dimensional array output by the synchronization unit 304, the position of the rectangular code having the same size as the unit code pattern is appropriately moved, and the position where the number of dots contained in the break is equal is the boundary of the unit code pattern Detect as position. A code pattern in which information is embedded with a unit code pattern of ₉ C ₂ if the number of even dots is 2, and a code pattern in which information is embedded with a unit code pattern of ₉ C ₃ if the number of dots is 3 In this way, the information embedding method can also be determined. Details of the unit code pattern boundary detection processing will be described later.

  The synchronization code detection unit 306 detects a synchronization code with reference to the type of each unit code pattern detected from the two-dimensional array. The direction (90 degree unit) of the unit code pattern (or code block) is detected according to which of the four types of synchronization codes (in the predetermined set) described with reference to FIG. 3 is detected. Can be corrected.

Each of the information code detection unit 307 and the position code detection unit 309 acquires an information code and a position code based on the position of the synchronization code from the code pattern whose angle is corrected.
The RS code decoding unit 308 decodes the information code detected using the same parameters (such as the number of blocks) used in the RS code encoding process in the code data image generation device, and records information for each information block (Divided recording information) is output.
Position code decoding section 310 extracts an M-sequence partial sequence from the position code acquired by position code detection section 309. And the position corresponding to the detected partial series is searched among M series used for the production | generation of a position code in a code data image generation apparatus. Since the synchronization code is arranged between the position codes, a value obtained by correcting the position offset by the synchronization code is calculated from the obtained M-sequence position, and is output as position information.

  The recording information restoration unit 311 generates an information index for specifying the position where the recording information block is arranged based on the position information decoded by the position code decoding unit 310 (for example, as described with reference to FIGS. 9 and 11). An information index is generated in the same manner as in (Method). Then, based on the order of the generated information indexes, the recording information decoded by the RS code decoding unit 308 is synthesized to restore the entire recording information.

<Synchronization processing>
Next, the synchronization process performed by the synchronization unit 304 will be described.
FIG. 15 is a diagram for explaining the outline of the synchronization process.
The synchronization unit 304 applies a virtual lattice to the dot pattern detected by the dot pattern detection unit 303, inspects the presence or absence of a dot within the grid of each lattice, and sets a portion where there is no dot to 0, A two-dimensional array is generated from a virtual lattice, with a certain part as 1. The direction (angle) of the virtual lattice can be estimated from the dot pattern. As is clear from FIGS. 1, 2, and 3, when two dots are selected from the code pattern, the distance between the two dots is closest to the two dots in the 0 degree direction or 90 degrees. This is a case where they are arranged adjacent to each other in the direction. Therefore, the closest pair of dots can be detected from a plurality of detected dot patterns, and the inclination angle of the code pattern can be detected from the direction in which the pair of dots is facing, and this can be determined as the grid direction. It can be. Further, since the distance between the two closest dots is the dot interval in the unit code pattern, the interval between the lattices used for the synchronization processing is the interval between the pair of the detected closest dots described above. It can be.

<Unit Code Pattern Boundary Detection Processing>
Next, boundary detection processing by the unit code pattern boundary detection unit 305 will be described.
FIG. 16 is a diagram for explaining the outline of the unit code pattern boundary detection process. FIG. 16A is an example of a code pattern configured with a ₉ C ₂ unit code pattern.
The target of the boundary detection is actually a synchronized two-dimensional array composed of the bit value 0 and the bit value 1 as shown in FIG. 15, but here the dot pattern is easy to catch intuitively. Will be described.

First, a grid pattern having a plurality of grids having the same grid size as the unit code pattern is prepared, and the grid pattern is converted into a code pattern as shown in FIGS. Scan (move) above. At this time, the number of dots included in each first mesh is counted, and the lattice pattern is fixed at a position where the variation in the number of first dots entering the first mesh is the smallest. This fixed position becomes the boundary position of the unit code pattern. _When the unit code pattern of ₉ C ₂ is used, the number of dots entering each square is 2 and uniform at the correct grid position shown in FIG. On the other hand, at the incorrect grid positions shown in FIGS. 16B and 16C, the number of dots entering each square varies in the range of 0 to 7.
If the boundary position of the unit code pattern can be specified as described above, each unit code pattern is inspected to detect the synchronization code, and depending on which of the four types of synchronization codes that are 90 degree rotationally symmetric is detected. The rotation of the code pattern is determined. Then, after the rotation correction, the position code and the identification code can be extracted from the corrected dot pattern.

<System configuration example>
Next, a system configuration example including the above-described code pattern generation device and information composite device according to the present embodiment will be described.
FIG. 17 is a diagram illustrating a system configuration example for generating a print document in which a code pattern is superimposed on a document. In this example, it is assumed that identification information for identifying an electronic document or a printed document on which the electronic document is printed is recorded by a code pattern as recording information. Note that any information can be used as the identification information. For example, it may be a 128-bit UUID or an ID generated from a server network address and printing time.
The system shown in FIG. 17 is configured by connecting a terminal device 11, a document management server 12, an identification information management server 13, and a printer 14 via a network.

The terminal device 11 is a computer device such as a personal computer. A user input operation is accepted, and an instruction to print an electronic document held in the document management server 12 is given.
The document management server 12 is a computer device such as a personal computer or a workstation. The identification information management server transmits the electronic document instructed to be printed and its attribute information (for example, information such as 5 pages of 10 page electronic document output, margin 5 mm, etc.).
The identification information management server 13 is a computer device such as a personal computer or a workstation, and corresponds to the code pattern image generation device of the present embodiment described above. Assigns, registers, and prints identification information for an electronic document to be printed. Since the identification information management server 13 adds different identification information for each printing medium (paper or the like) to be printed out, for example, when 5 copies of an electronic document of 10 pages are output in 2UP, 10 pages / 2 × 5 = 25 pieces of identification information are generated. The generated identification information is stored in a database in association with attribute information (storage location, print settings, layout information, etc.) of the received electronic document. Next, a print description language (PDL) is generated from the received electronic document and the generated identification information, and transmitted to the printer 14. The PDL includes a code pattern image generated from the identification information.
The printer 14 generates an image based on the PDL received from the identification information management server 13, and prints it out as a print image on a recording medium such as paper using an image forming material such as toner.

In the above example, the code pattern image is generated in the identification information management server 13, but the code pattern image can also be generated in the printer 14. In this case, the identification information management server 13 adds the identification information to the PDL generated from the electronic document and transmits it to the printer 14. Then, the printer 14 generates a code pattern image from the identification information, and outputs the code pattern image superimposed on the electronic document.
In this system configuration example, an example in which a code pattern image is generated by the identification information management server 13 or the printer 14 is shown, but it can also be generated by the document management server 12. In that case, the document management server 12 transmits only the attribute information of the electronic document to the identification information management server 13. The identification information management server 13 calculates the number of necessary identification information from the received attribute information, associates the received attribute information with the issued identification information, and transmits the identification information to the document management server 12. The document management server 12 generates a code pattern image based on the received identification information and transmits it to the printer 14 together with the electronic document information.

FIG. 18 is a diagram showing a system configuration example for reading information from a recording medium (paper) on which a code pattern according to the present embodiment is printed.
The system shown in FIG. 18 includes the terminal device 11, the document management server 12, and the identification information management server 13 described above, and the electronic pen 20 that is the information decoding device in the present embodiment described above. The configuration of the electronic pen 20 will be described later.

  When the surface of the recording medium (hereinafter referred to as a paper surface) is written with the electronic pen 20, a code pattern image printed on the paper surface is captured by the imaging device of the electronic pen 20. The code pattern image is decoded by the function of the electronic pen 20, and position information and identification information described in the code pattern image are acquired. Since the electronic pen 20 captures an image at a speed of about 70 fps to 100 fps, a plurality of position information and identification information can be acquired by a single writing operation. Since the same information is embedded in the identification information regardless of the position on the page, the reliability of the identification information can be improved by comparing the plurality of acquired identification information and selecting the most detection results. . Although the position information differs depending on the position on the paper surface, the position information obtained by the writing operation that continuously moves the electronic pen 20 is the part where the decoding failed by verifying the continuity of the position (coordinates). Can be detected or interpolated. These position information and identification information are stored in the memory of the electronic pen 20 as writing information.

The terminal device 11 acquires writing information from the electronic pen 20 and transmits it to the identification information management server 13.
The identification information management server 13 searches the attribute information of the corresponding electronic document based on the identification information included in the received writing information. When the attribute information of the corresponding electronic document is detected, the original electronic document is accessed, and an electronic document (written electronic document) for reflecting the writing information is generated from the original electronic document. Prior to this processing, whether or not there is a written electronic document is searched, and when the written electronic document is detected, the written information acquired this time may be reflected in the written electronic document. Moreover, it is good also as a structure which inquires whether the terminal device 11 produces | generates a new written electronic document newly, or adds written information to the detected written electronic document. The written electronic document can be easily retrieved and acquired by registering the attribute information (storage location) of the written electronic document in the identification information management server 13 in advance.

  The written electronic document is generated in a format in which a portion corresponding to the original electronic document cannot be edited (for example, a PDF document format of Adobe Systems, or a DocumentWorks format of Fuji Xerox). In the written electronic document, the electronic document portion cannot be edited, but the written information can be added later. For example, when the information written on the recording medium is digitized once and then written again on the same recording medium, the added writing information can be added to the written electronic document.

<Configuration of electronic pen>
Next, the configuration of the electronic pen 20 that is an information decoding device will be described.
FIG. 19 is a diagram illustrating a configuration example of the electronic pen 20.
In the electronic pen 20 shown in FIG. 19, the control circuit 21 is a circuit that controls the operation of the electronic pen. The control circuit 21 includes an image processing unit 25 that detects a code pattern from an input image and a data processing unit 26 that decodes the code pattern and acquires writing information. The control circuit 21 includes a pressure sensor 22 for detecting a writing operation by the electronic pen, an infrared LED 23 for illuminating the paper surface, an infrared CMOS 24 for inputting an image, a memory 27 for storing writing information, A communication circuit 28 for communicating with an external device and a battery 29 for driving the electronic pen 20 are connected.

  When the writing operation is detected by the pressure sensor 22 attached to the end of the electronic pen 20, the infrared LED 23 is turned on, and an image on the paper surface is captured by the infrared CMOS 24. The image sensor is not limited to a CMOS sensor, and other image sensors such as a CCD may be used. The lighting timing of the infrared LED 23 is pulse-lit in synchronization with the shutter timing of the infrared CMOS 24 in order to suppress power consumption. As the infrared CMOS 24, a global shutter type CMOS capable of simultaneously transferring captured images is used. In order to reduce the influence of disturbance, a visible light cut filter is disposed on the entire surface of the light receiving unit. Further, the infrared CMOS 24 captures an image with a period of about 70 fps to 100 fps (frame per second).

  The control circuit 21 acquires a code pattern image from the captured image and decodes it to acquire writing information (coordinate information and identification information) embedded in the code pattern image. The decrypted writing information is stored in the memory 27. The communication circuit 28 transmits writing information stored in the memory 27 and receives control information from the outside. When a decryption key for decrypting the code pattern is necessary, the decryption key is received from the outside through the communication circuit 28 and stored in the memory 27.

The system described with reference to FIGS. 17 to 19 is an example of a system to which the code pattern image generation apparatus and the information decoding apparatus for recording recording information of an arbitrary amount of information with the code pattern according to the present embodiment can be applied. However, the present invention is not limited to such a system.
Further, the information decoding device may be realized by a scanner device or the like in addition to the electronic pen 20 described above.

It is a figure which shows the example of the unit code pattern of the code pattern image used by this embodiment. It is a figure which shows 84 types of dot arrangement | positioning which the unit code pattern shown in FIG. 1 can take. It is a figure which shows the example (5 sets) of four types of unit code patterns which can be used as a synchronous code. It is a figure which shows the example of the code block used by this embodiment. It is a figure which shows the structure of the code | symbol pattern image generation apparatus by this embodiment. It is a chart which matches the set number of the synchronous code | cord | chord used by this embodiment, the division | segmentation number of information, and information amount. It is a figure which shows a mode that the M series was divided into blocks and allocated to each position code as position information. It is a figure explaining the content of the division | segmentation of a recording information, and an encoding process. It is a figure explaining the production | generation method of the information index of this embodiment. It is a figure explaining the production | generation method of the information index of this embodiment. It is a chart which matches the value of an X direction division | segmentation index and a Y direction division | segmentation index, and an information index. It is a figure which shows a mode that a recording information block is arrange | positioned based on the information index of this embodiment. It is a figure which shows the example of a data structure in the case of inserting the data which show the division | segmentation number of recording information in the recording information block of this embodiment. It is a figure which shows the example of the information index expressed with the kind of position code. It is a figure which shows the structure of the information decoding apparatus by this embodiment. It is a figure explaining the outline | summary of a synchronization process. It is a figure explaining the outline | summary of the boundary detection process of a unit code pattern. It is a figure which shows the system configuration example which produces | generates the printing document on which the code pattern was superimposed on the document. It is a figure which shows the system configuration example which reads information from the recording medium (paper) on which the code | symbol pattern by this embodiment was printed. It is a figure which shows the structural example of an electronic pen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Code block production | generation part, 111 ... Synchronization code selection part, 121 ... M series acquisition part, 122 ... M series division | segmentation part, 131 ... Information acquisition part, 132 ... Information division part, 133 ... RS encoding part, 141 ... Code | symbol Block arrangement unit, 200 ... output image generation unit, 201 ... bit pattern holding unit, 202 ... pattern selection unit, 203 ... image output unit

Claims (8)

Information acquisition means for acquiring recording information recorded on the recording medium;
A position code image pattern that is arranged in a certain section and represents position information unique to a position on the recording medium; and an information code image pattern that is arranged in the section, and divides the recording information. Image generating means for generating an image in which specific recording information is described by the information code arranged in the plurality of sections by distributing the plurality of pieces of partial information obtained in the plurality of sections. ,
In the image generated by the image generation means, section identification information is set according to the position information of the section represented by the position code and the number of the sections describing the specific recording information, and the same An image generating apparatus, wherein the information code representing the same partial information among the partial information obtained from the specific recording information is arranged in the section to which the section identification information is assigned . Information acquisition means for acquiring recording information recorded on the recording medium;
A position code image pattern representing a position information unique to a position on the recording medium arranged in a certain section, and an information code image pattern representing the record information arranged in the section, Image generating means for generating an image in which specific recording information is described by the information code arranged in the section of
The image generated by the image generation means is further provided with a specific code for specifying the number and arrangement of the sections in which the entire specific recording information is described. An image generation unit for generating an image in which predetermined information is recorded by two-dimensionally arranging a code block in which a position code representing a position on a recording medium and an information code representing recording information are described in an image pattern;
An information dividing unit that divides the recording information into a plurality of pieces of partial information according to the number of code blocks necessary for recording the recording information;
A code block arrangement unit that arranges the code block in which the partial information is described by the information code at a position represented by the position code ;
For each code block group including the number of code blocks necessary for recording the recording information, the code block arrangement unit determines the position of each code block in the code block group and the number of divisions of the recording information. An image generation apparatus characterized by assigning an index set accordingly and arranging the code block describing the same partial information at the position of the code block to which the same index is assigned . The image generation apparatus according to claim 3 , wherein the code block includes a specific code that specifies the number and arrangement of the code blocks included in the code block group. Reading means for reading the image of the code pattern printed on the surface of the recording medium;
Code detecting means for detecting a position code representing a position and an information code representing recorded information from the image read by the reading means;
Identifying a section in which the information code is arranged based on position information obtained from the position code detected by the code detecting means, and identifying a plurality of sections in which recording information divided into a plurality of partial information is recorded A zone identification means for generating information;
Information acquisition means for acquiring a code string arranged in the section identified by the section identification means, and combining the code strings acquired from the plurality of sections based on the identification information to acquire the recording information An information reading apparatus comprising: 6. The information reading apparatus according to claim 5 , wherein the section identifying unit identifies the order of the code strings arranged in the section with respect to the plurality of identified sections . A recording medium having an image pattern drawn on its surface,
An image pattern of a position code that is arranged in a certain section and represents position information unique to the position on the recording medium;
Arranged in the section formed by the image pattern of the position code, the image pattern of the information code representing the recording information is drawn,
The image pattern of the information code is specified by the information code arranged in the plurality of sections by distributing the plurality of pieces of partial information obtained by dividing the recording information to the plurality of sections. Record and
The section identification information is set according to the position information of the section represented by the position code and the number of the sections describing the specific recording information, and the specific section is assigned the same section identification information. A recording medium in which the information code representing the same partial information among the partial information obtained from the recorded information is arranged . A recording medium having an image pattern drawn on its surface,
One or a plurality of areas in which a plurality of code blocks including a position code representing a position on the recording medium and an information code representing recording information are arranged are formed,
For each code block group including the number of code blocks necessary for recording the record information, an index set according to the position of each code block in the code block group and the number of divisions of the record information is set. A recording medium in which the code block in which the same part of the recording information is described is arranged at the position of the code block to which the same index is assigned .

Images