JP2000269824A - Data encoding device and data decoding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data encoding device encoding bit data through the use of the two types of error correction systems of a random error correction encoding system and a burst error correction encoding system by arranging encoded bit data in a regulated two-dimensional area in a matrix form, generating a two-dimensional picture and printing it in a medium. SOLUTION: A hamming code encoder 4A gives random error correction functions to error bits which dispersively exist in a bit data string. A Reed- Solomon code encoder 5A gives burst error correction functions which intensively occur to bit data. A two-dimensional picture generation means 6A generates a two-dimensional picture based on bit data on a work memory 9A, to which random/burst error correction codes are added. Respective blocks are arranged in one direction in a row or a column in a specified two-dimensional area. The generated two-dimensional picture is inputted to a printer 1A and is printed on the medium of paper or the like as the two-dimensional picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data encoding device for storing data as an image in a two-dimensional defined area such as a two-dimensional code, and a data decoding device for decoding the stored encoded data. Things.

[0002]

2. Description of the Related Art Systems using barcodes for product distribution management and component management in factories have become widespread, but with the development of image processing technology and the fact that CCD television cameras and the like have become cheaper and easier to use. Thus, development and use of two-dimensional codes that store a larger amount of information than one-dimensional bar codes are being performed.

A two-dimensional code generally has an error correction function for noise such as corruption of bit data in the two-dimensional code by utilizing a large amount of information storage. For example, the international automatic recognition industry association (AIM JAPAN) standard document "2D code-QR code-technical specification AIMJ-
In a two-dimensional code called a QR code described in “TC-3-1”, by applying either Reed-Solomon code or Hamming code and adding bit data for error correction, It has the function of correcting bit data reading errors due to noise such as dirt on the dimensional code.

The function of correcting the bit data read error includes a noise pattern having a high error correction efficiency and a noise pattern having a low correction efficiency, depending on an applied coding system. For example, the Reed-Solomon coding method works effectively on burst errors, and the Hamming coding method works effectively on random errors. In addition, there are an extended Hamming code and a BCH code (Bose / Chaudhuri / Hocquengen code) as effective coding methods for random errors, and an erasure code and an adjacent code as effective coding methods for burst errors.

[0005]

However, in the above-mentioned conventional data encoding apparatus and data decoding apparatus, linear noise appearing on a vertical stripe which is likely to appear when a two-dimensional image is printed, or a two-dimensional image which is not easily printed. In some cases, error correction cannot be performed on linear noise that is linear on a two-dimensional image, such as linear noise on horizontal stripes due to shadows that appear when a medium such as paper that has been bent is bent.

[0006] For example, the Reed-Solomon encoding method is as follows.
As shown in FIG.
0 to Bj, and these blocks B0 to Bj
Parity blocks Bp0 to Bpj are added to Bj to provide a burst error correction function (a function of correcting errors in block units).

However, in this case, the number of blocks that can be corrected is limited, and error correction cannot be performed on linear noise that extends over a plurality of blocks beyond this limit.

In the Hamming coding method, bit data is divided into a plurality of sets Q0 to Qk as shown in FIG. 21 and error correction bits Qp0 to Qpk are added to each of the sets Q0 to Qk. It has a random error correction function (a function of correcting each bit constituting the set).

However, in this case, the number of bits that can be corrected in one set is limited, and an error of the number of bits exceeding this limit, for example, a linear noise in the length direction of the set, is prevented. Error correction is not possible.

Furthermore, in the above-described conventional data encoding apparatus and data decoding apparatus, it is not possible to select an error correction encoding method that minimizes the decoding processing time for these frequently occurring noises.

SUMMARY OF THE INVENTION The present invention addresses the above-described situation and provides a data encoding apparatus and a data decoding apparatus for encoding bit data using two types of error correction systems, a random error correction encoding system and a burst error correction encoding system. It is intended to provide a device. In addition, the error correction capability can be reliably used regardless of the direction of the linear noise, and the bit data rearrangement map can be changed in accordance with the direction of the linear noise that can easily be superimposed on the two-dimensional image. The purpose is to minimize the decoding processing time including the correction time.

[0012]

The present invention employs the following means to achieve the above object.

That is, the data encoding device of the present invention comprises:
Bit data is encoded using at least one type of error correction code by two types of error correction methods, a random error correction code method and a burst error correction code method. The encoded bit data is arranged in a prescribed two-dimensional area in a matrix to generate a two-dimensional image and print it on a medium.

In this case, when the encoded bit data is rearranged based on the rearrangement map, and when the encoded bit data is arranged on the prescribed two-dimensional area based on the rearrangement map, A set of bit data to which the random error correction code is added may be arranged linearly in any one of a row and a column in the prescribed two-dimensional area.

Further, a relocation map holding means for holding a plurality of the relocation maps and a relocation map designating means for selecting a relocation map to be used by the relocation means are provided. It is also preferable to select a relocation map in which the direction of the most frequent bit error and the length direction of the set of bit data intersect.

On the other hand, the data decoding device of the present invention includes a two-dimensional image reading means for reading a two-dimensional image printed on a medium by the data encoding device of the present invention, and converting the two-dimensional image into bit data of electronic data. Random error correction means for performing error correction and decoding on a set of bit data to which a random error correction code has been added in the converted bit data; and a set of the bit data to which a burst error correction code has been added. And a burst error correcting means for performing error correction and decoding on the data.

In this case, at the subsequent stage of the two-dimensional image reading means, there is provided a map arrangement restoration processing means for converting the read two-dimensional image such as the two-dimensional code into bit data before rearrangement based on the rearrangement map. It is also possible to provide.

In the data encoding device and the decoding device according to the present invention, the burst error correction code acts on noise in the length direction of a set of randomly encoded bit data. The random error correction code acts on noise that penetrates a plurality of burst-coded bit data blocks. Therefore, regardless of the direction of noise on the two-dimensional image, it is possible to reliably use the error correction capability. Furthermore, by using a plurality of random error correction codes and burst error correction codes,
Error correction can be performed even for noise having a more complicated shape.

The bit data can be rearranged according to the direction of the noise by creating a rearrangement map of the bit data, or by changing the rearrangement map according to the direction in which the linear noise is likely to be on the two-dimensional image. The direction of the block of data and the direction of the noise intersect with each other, and the random error correction coding scheme with a fast correction time is preferentially used, thereby minimizing the decoding processing time including the error correction time. It is possible.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described.

(Embodiment 1) FIG. 1 is a block diagram of a data encoding / decoding apparatus according to Embodiment 1 of the present invention. For the configuration of bit data encoding in this apparatus, refer to the flowchart of FIG. Will be explained. In FIG. 1, solid arrows indicate the flow of processing, and white arrows indicate the flow of bit data.

A predetermined number, for example, 16 bits of bit data input from the data input / output means 3A is input to the work memory 9A, and together therewith, a Hamming code encoder 4A (here, a case where the 8.4 Hamming coding method is used) is used. Example) starts. As shown in FIG. 4A, the hamming code encoder 4A has the work memory 9A.
The above bit data is converted into a set Da to Dd for each predetermined number of bits.
(Here, four sets of four bits), and as shown in FIG. 3B, error correction bits 5 to 5 derived from the above (8.4) Hamming coding method are respectively applied to the sets Da to Dd. 8 added by 4 bits (steps 1a to 2a)
To obtain new sets Ha to Hd in units of 8 bits. still,
In FIG. 4 and the subsequent figures, data of bits surrounded by a thick frame is “1”, and data of bits not surrounded is “0”.
It is assumed that

In this (8.4) Hamming coding method,
As described above, one bit error among the eight bits of data forming one set can be corrected, so that the hamming code encoder 4A performs error correction for error bits discretely present in the bit data sequence. That is, a random error correction function for correcting the error is provided. However, the above 8
When it is desired to correct an error of two or more bits in bit data, it is necessary to use a Hamming coding method having a larger number of corrected bits.

As described above, when the random error correction bits are added by the Hamming code encoder 4A,
Next, the Reed-Solomon code encoder 5A is activated.
This Reed-Solomon code encoder 5A is shown in FIG.
The four sets R of the 8-bit data shown in FIG.
Four parity blocks Re to Rh are generated and assigned to a to Rd (= Ha to Hd) as shown in FIG. 3C (step 3a).

The four parity blocks Re to Rh
Is composed of 8 bits in one block, and the error correction capability to which this Reed-Solomon coding method is applied is four sets of bit data sets Ra to Rd and parity blocks Re to
An error of up to two blocks can be corrected for eight blocks Ra to Rh in which four of Rh are combined. Therefore, the Reed-Solomon code encoder 5A has a function of correcting errors intensively occurring in the bit data forming one block, that is, a function of correcting a burst error. However, if it is desired to correct more blocks, it is necessary to use more correction blocks.

In the above description, the random encoding is performed first, but the burst encoding may be performed first.

Next, the two-dimensional image generating means 6A is activated, and the two-dimensional image generating means 6A is based on the bit data to which random and burst error correction codes are added on the work memory 9A. Generate an image, for example, a two-dimensional code. Here, when replacing the bit data with the two-dimensional code, the blocks Ra to Rh obtained by the Reed-Solomon code encoder 5A are used as a unit as shown in FIG.
Are arranged side by side in one direction of either a row or a column in a prescribed two-dimensional region (the number of rows and columns of bit arrangement is a predetermined number) (step 4a).

This arrangement order is described in the rearrangement map 10M as the rearrangement means 10A shown in FIG. 5B, and the two-dimensional image generation means 6A performs the above-described bit data block Ra based on the rearrangement map 10M. To Rh in FIG.
Array as shown in (c). 5 (b) and 5 (c)
In the above, a to h indicate blocks, and 1 to 8 paired with a to h indicate the order of bit data in one block.

The two-dimensional code generated in this way is input to the printer 1A and printed as a two-dimensional image on a medium such as paper (step 5a).

Next, a decoding process of bit data in the data encoding / decoding apparatus according to the first embodiment will be described with reference to a flowchart of FIG.

As described above, 2 printed on a medium such as paper
The two-dimensional image is read by the scanner 2A (step 1).
b) is input to the work memory 9A, and at the same time, the map rearrangement and restoration processing means 13A is activated.

In the map arrangement restoration processing means 13A,
The bit data rearranged by the two-dimensional image generation means 6A based on the rearrangement map 10M is converted into the same rearrangement map 10M.
Is restored to the original bit data before sorting (step 2b).

When the bit data is restored in this way,
The Hamming code decoder 7A is activated (step 3).
b).

Here, as shown in FIG. 6, if there is noise that penetrates obliquely in a straight line on the two-dimensional image, if the noise is in a different direction from the block arranged in a straight line, Since the number of bits broken by noise in one block is 1 bit or less, the Hamming code decoder 7A corrects error bits by a random error correction function (step 4b-1).

As shown in FIG. 7, if the noise is in the same direction as the blocks arranged in a straight line, and if two or more bits in one block are broken, the bit data is transmitted to the Hamming code decoder 7A. The corrected internal state is processed by the Reed-Solomon code decoder 8A in the next step (step 4b-2).

That is, when the processing in the Hamming code decoder 7A is completed, the Reed-Solomon code decoder 8A is activated, and the burst error correction processing is performed here.

That is, as shown in FIG. 6, even if there is a linear noise obliquely penetrating the two-dimensional image, if the noise has a different direction from the blocks arranged in a straight line, the noise in one block In step 4b-1, the error has already been corrected by the hamming code decoder 7A because the number of bits corrupted by noise is 1 bit or less.

On the other hand, as shown in FIG. 7, there is a linear noise penetrating vertically on the two-dimensional image, and the noise has the same direction as the blocks arranged in a straight line. If an error has occurred in two or more bits, as described above, this error bit is passed through to the Reed-Solomon code decoder 8A without being corrected by the Hamming code decoder 7A. At this time, since the other seven blocks are intact, it is possible to correct the block containing error bits based on the seven intact blocks by applying a burst error correction function in the Reed-Solomon code decoder 8A. It is possible (step 5b).

As described above, when the original bit data is restored on the work memory 9A via the Hamming code decoder 7A and the Reed-Solomon code decoder 8A, the bit data is transferred to the data input / output means 3A and output. (Step 6b to Step 7b).

(Embodiment 2) Next, a data encoding / decoding apparatus according to Embodiment 2 of the present invention will be described.

FIG. 8 is a schematic diagram showing the configuration of a data encoding / decoding device according to the second embodiment. The rearrangement means 10A of the data encoding / decoding device according to the first embodiment uses the second embodiment. Is replaced by a rearrangement map database 12A and a keyboard 11A. As in the case of FIG. 1, solid arrows indicate the flow of processing, and white arrows indicate the flow of bit data.

The rearrangement map database 12A serves as a rearrangement map holding means and stores a plurality of types of rearrangement maps 1
0M are provided, and the keyboard 11A specifies which of the plurality of relocation maps is to be used as the relocation map specifying means. The relocation map designating means is not limited to the keyboard 11A as long as the means can be designated by the user. For example, the relocation map is displayed on the touch panel by name, number, or the like.
You may make a user select.

FIG. 9 shows a procedure for encoding bit data in the data encoding / decoding apparatus according to the second embodiment.
This will be described with reference to the flowchart of FIG.

Steps 1c to 4 in FIG.
The procedure up to c is the same as in the case of the data encoding / decoding apparatus according to the first embodiment described with reference to FIG. 2 (see steps 1a to 5a in FIG. 2), and a description thereof will be omitted.

In the data encoding / decoding apparatus of the second embodiment, a plurality of relocation maps having different block directions as shown in FIGS. 10 and 11 are provided in the relocation map database 12A. In consideration of the direction of the linear noise that is likely to occur, the user selects a rearrangement map from which the bit arrangement is to be executed from among the plurality of rearrangement maps, and selects the rearrangement map via the keyboard 11A. Is specified (steps 6c to 5c).

Based on this designation, the two-dimensional image generation means 6A executes bit rearrangement of the two-dimensional image on the work memory 9A (step 6c). The relationship between the direction of the linear noise and the arrangement direction of the bit data at that time is shown in FIG.
And FIG.

As shown in FIG. 7, the error correction of the Reed-Solomon coding method used for error correction in units of blocks requires a longer processing time for error correction than the error correction of the Hamming coding method. Therefore, in order to shorten the processing time, first, the error correction is performed by the Hamming coding method, the number of error bits is reduced as much as possible, and then the error correction of the Reed-Solomon coding method is executed.

Therefore, the error correction in the Hamming code system works effectively, that is, so that a state in which many bits are destroyed in a block does not occur.
A relocation map 10M having a different block length direction and noise direction is selected.

When such a procedure is adopted, the selection of the rearrangement map 10M is determined by the direction in which noise is generated as follows.

For example, when a two-dimensional image is printed by a printer or the like, a linear noise N1 in the same direction as the paper discharge direction is likely to occur due to contamination of the roller as shown in FIG. At that time, a direction in which the length direction of the block Bk is orthogonal to the noise N1 shown in FIG.
That is, a rearrangement map in which the length direction of the block Bk is a dot arrangement in the column direction is selected.

[0051] Further, via a facsimile machine or the like,
In the case of printing a two-dimensional image, when a communication error occurs as shown in FIG. 11, the error is printed as a black line or a white line, and the black line or the white line is directed in a direction perpendicular to the paper discharging direction. Often appear as a linear noise N3 in FIG. At this time, as shown in the figure, a rearrangement map is selected in which the length direction of the block Bk is orthogonal to the linear noise N3, that is, the length direction of the block Bk is a dot arrangement in the row direction.

It is conceivable that an inclined noise is generated differently from the cases of FIGS. 10 and 11, but FIG.
As shown in (1), it is possible to employ a rearrangement map in which the bit data constituting the block Bk is arranged obliquely so as to be orthogonal to the noise N3.

Further, as a method for simultaneously satisfying the two states shown in FIGS. 10 and 11, it is conceivable to arrange bit data obliquely in the sheet discharging direction. The two-dimensional image created in this way is sent to the printer 1A and printed on a medium such as paper as a two-dimensional image (step 7).
c).

The operation of decoding the bit data in the data encoding / decoding apparatus of the second embodiment is the same as that described in the first embodiment with reference to FIG. Description is omitted.

However, in the data encoding / decoding device according to the second embodiment, step 5c in the flowchart of FIG.
In the above, since the rearrangement map is selected through the keyboard 11A in order to avoid burst error correction which requires more time for error correction than random error correction for the linear noise in the direction with the highest frequency of occurrence, the decoding time is short. The possibility of doing it will increase.

(Embodiment 3) FIG. 13 is a block diagram showing a configuration of a data encoding / decoding device according to a third embodiment of the present invention. FIG. 14 shows a configuration of bit data encoding in this device. This will be described with reference to the flowchart of FIG. As in the case of FIG. 1, solid arrows indicate the flow of processing, and white arrows indicate the flow of bit data.

As described with reference to FIG. 1, a predetermined number, for example, 16-bit data input from the data input / output means 3A is input to the work memory 9A, where the processing described below is performed (step). 1d).

When the bit data is input to the work memory 9A as described above, the pattern detecting means 15A is activated, and the pattern detecting means 15A determines the relationship between the direction of the sheet and the direction of the line printed on the sheet (line A direction pattern indicating whether the direction is a long direction or a short direction of the sheet) is detected, and the detection result is passed to the encoding method combination determination means 14A. The encoding method combination determination means 14A determines which of the encoding methods described below to use in combination and in what order when encoding the bit data based on the directional pattern (step 2d).

The direction pattern detected by the pattern detecting means 15A is not limited to the relationship between the direction of the paper and the row direction, but may be a noise pattern in a specific use environment. May be reflected. In the present embodiment, Hamming code, Reed-Solomon code,
Three types of BCH codes (Bose / Chaudhuri / Hocquengen codes) are prepared.

Of these, Hamming codes and BCH codes are classified as random error correction codes, and Reed-Solomon codes are classified as burst error correction codes. In the following description, a case where bit data is encoded by applying the Hamming code, the Reed-Solomon code, and the BCH code in this order will be described as an example.

It should be noted that the prepared encoding systems are not limited to the above three types, but more types of encoding systems may be used, and instead of using all the prepared encoding systems, A necessary type of encoding method may be used depending on the situation. Also, for example, a Hamming code,
The same coding scheme may be used any number of times such that the coding is performed in the order of the BCH code and the Hamming code. Further, the coding method combination determining means 14A does not determine the combination of the coding methods depending on the direction pattern detected by the pattern detecting means 15A as described above, but follows a predetermined combination and order. It may be.

In this embodiment, for the bit data in the work memory 9A as described above, first, the Hamming coding method, which is the first coding method of the combination determined by the coding method combination determining means 14A, is used. Be executed. Here, it is assumed that the (8.4) Hamming coding method is used, and the procedure for adding the Hamming code to the bit data is the same as that in the first embodiment of the present invention.

As described above, when the Hamming code encoder 4A adds a Hamming code (random error correction bit) to the bit data, the Reed-Solomon code encoder 5A is activated, and the Reed-Solomon code is added. This procedure is the same as that of the first embodiment of the present invention, and the description is omitted (steps 1d to 5d).

As described above, the bit data to which the burst error correction bits are added by the Reed-Solomon code encoder 5A uses the BCH code encoder 16A (here, (16.15) BCH coding method) as an example. ).

The BCH code encoder 16A has the structure shown in FIG.
The block R of the 8-bit data shown in FIG.
a to Rh, bits included in the blocks Ra and Rc, a total of 16 bits, and 1 for the 16 bits
Generate and add a 5-bit parity block α to generate a block Σα
And Similarly, a block Σβ composed of bits of blocks Rb and Rd and a corresponding parity block β, a block Σγ composed of bits of blocks Re and Rg and a corresponding parity block γ, bits of blocks Rf and Rh and corresponding bits A block Σδ composed of a parity block δ is generated (step 5d). The error correction capability to which the BCH coding method is applied can correct up to a 3-bit error in one lump composed of 31 bits.

The bit data to which a plurality of types of error correction codes have been added is passed to the two-dimensional image generating means 6A (step 6d). In the two-dimensional image generating means 6A, the bit data described above is transferred to the rearrangement map 10M as the rearrangement means 10A shown in FIG.
They are arranged as shown in (c) to generate a two-dimensional code (step 7d).

In FIGS. 16B and 16C, a
To h indicate the above blocks Ra to Rh, and 1 to 8 paired with a to h indicate the order of bit data in one block. Further, α to δ represent parity blocks, and 1 to 8 paired with α to δ represent the order of bit data in the parity blocks α to δ.

The two-dimensional code generated in this way is input to the printer 1A and printed on a medium such as paper as a two-dimensional code image (step 8d).

Next, the operation of decoding bit data in the data encoding / decoding apparatus of the third embodiment will be described with reference to the flowchart of FIG.

As described above, 2
The dimensional code image is read by the scanner 2A and input to the work memory 9A (step 1e).

The map arrangement restoring means 13A applies the bit data input to the work memory 9A as described above to the bit data input to the work memory 9A based on the same rearrangement map 10M used by the two-dimensional image generating means 6A. The original bit data before the rearrangement is restored (step 2e).

The pattern detecting means 15A detects the directional pattern based on the bit data restored on the work memory 9A as described above, and notifies the contents to the coding scheme combination determining means 14A. The coding scheme combination determining means 14A that has received the notification determines the coding schemes combined and the order of use (step 3e). In accordance with the order determined here, each decoder is activated as described below and decodes bit data. In this example, it is assumed that the above-mentioned order is the order of the Hamming code, the Reed-Solomon code, and the BCH code, and the bit data arranged in the original state by the map arrangement restoration processing means 13A is first passed to the Hamming code decoder 7A. (Step 4e).

Here, as shown in FIG. 18, if the noise N4 occupying a large area on the two-dimensional code image is present, one correction set (including an error correction code including eight bits) Of the set of bits: in this case block R), three blocks R of block Rc (bits c1 to c8), block Rd (bits d1 to d8), and block Re (bits e1 to e8) are corrupted by noise N4. Since each bit is 2 bits,
The Hamming code decoder 7A cannot correct error bits by the random error correction function (step 5).
e-2: see step 5e-1).

Next, the bit data is passed to the Reed-Solomon code decoder 8A, where a burst error correction process is performed (step 6e). However, as shown in FIG. 18, when the noise N4 occupying a large area on the two-dimensional code image remains, the blocks Rc and R among the blocks R of the correction unit viewed from the Reed-Solomon coding method are used.
The three blocks d and Re have been destroyed, and the bit data has been destroyed beyond the performance of the Reed-Solomon encoding system in which up to two blocks used in this example can be corrected.
Therefore, the error bit cannot be corrected here (step 7e-2: see step 7e-1).

Next, the bit data is passed to the BCH code decoder 17A, where it is corrected (step 8).
e). The correction here is performed on 31 bits (a1 to a8, α1 to α8, c
1 to c8, α9 to α15) are considered to be the one block Σ (here, Σα), the error bits can be corrected since the block Σα has three or less error bits. (Step 9e).

As described above, the original bit data is restored via the Hamming code decoder 7A, Reed-Solomon code decoder 8A and BCH code decoder 17A, transferred to the data input / output means 3A, and output (step 10e).
-Step 11e).

As in the case of the second embodiment, a plurality of kinds of rearrangement maps are prepared in the third embodiment, and the user can select an appropriate rearrangement map by using a keyboard or the like in consideration of the noise generation direction and the like. You can make it selectable. In addition, the rearrangement map is not limited to the arrangement order illustrated here, but may employ an arbitrary arrangement order within a prescribed two-dimensional area.

As described above, in each embodiment of the present invention,
The above rearrangement map is omitted, and the bit data transferred from the Hamming code encoder 4A or the Reed-Solomon code encoder 5A is used as it is for the two-dimensional image generation means 6A.
Can be used as a two-dimensional image.

Further, the applicant of the present application stores image data corresponding to a document image input from image input means such as a scanner as an image file in a built-in magnetic disk or the like, and stores the stored image file again in a printer or the like. An image information processing apparatus that can print more is proposed. According to this, it is also possible to print the two-dimensional code on a specific page of the document image and specify the document image stored as described above based on the two-dimensional code.

Further, in the above description, a two-dimensional code has been described as an example. However, a two-dimensional image to which the present invention is applied is not limited to a two-dimensional code, but can be obtained by encoding a set of bit data. Includes general two-dimensional images.

[0081]

As described above, according to the present invention, bit data is encoded and decoded by using two types of error correction systems, that is, a random error correction coding system and a burst error correction coding system. For this reason, the above-mentioned burst error correction code acts on the noise in the length direction of a set of randomly encoded bit data, and the above noise on the noise penetrating a plurality of blocks of burst encoded bit data. The random error correction code works. Therefore, 2
Regardless of the noise in any direction on the two-dimensional image, it is possible to reliably use the error correction capability. In addition, by using a plurality of random error correction codes and burst error correction codes, error correction can be performed even on noise having a more complicated shape.

Further, it is possible to create a bit data rearrangement map in accordance with the direction of the noise, or to change the rearrangement map depending on which direction of linear noise is likely to be on the two-dimensional image. . Thereby, the direction of the block of the bit data and the direction of the noise intersect with each other, so that the random error correction coding method with a fast correction time can be preferentially used. Therefore, it is possible to minimize the decoding processing time including the error correction time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a data encoding / decoding device according to a first embodiment of the present invention.

FIG. 2 is a flowchart at the time of data encoding in the data encoding / decoding device of the first embodiment.

FIG. 3 is a flowchart at the time of data decoding in the data encoding / decoding device of the first embodiment.

FIG. 4 is an explanatory diagram showing a bit data encoding procedure in the data encoding / decoding device according to the first embodiment;

FIG. 5 is an explanatory diagram showing dot rearrangement specifications on a two-dimensional image in the data encoding / decoding device according to the first embodiment;

FIG. 6 is a diagram illustrating an example of a case where linear noise is applied in a direction crossing each block.

FIG. 7 is a diagram illustrating an example of a case where linear noise is present in the same direction as one block.

FIG. 8 is a configuration diagram illustrating a data encoding / decoding device according to a second embodiment of the present invention.

FIG. 9 is a flowchart at the time of data encoding in the data encoding / decoding device of the second embodiment.

FIG. 10 is a diagram showing the specification of a rearrangement map when linear noise in the same direction as the paper discharge direction is applied.

FIG. 11 is a diagram showing the specification of a rearrangement map when a linear noise in a direction perpendicular to the sheet discharging direction is applied.

FIG. 12 is a diagram showing specifications of a rearrangement map for arranging bit data obliquely with respect to a sheet.

FIG. 13 is a configuration diagram illustrating a data encoding / decoding device according to a third embodiment of the present invention.

FIG. 14 is a flowchart at the time of data encoding in the data encoding / decoding device of the third embodiment.

FIG. 15 is an explanatory diagram showing an encoding procedure of bit data in BCH encoding.

FIG. 16 is an explanatory diagram showing dot rearrangement specifications on a two-dimensional image in the data encoding / decoding apparatus according to the third embodiment.

FIG. 17 is a flowchart at the time of data decoding in the data encoding / decoding device of the third embodiment.

FIG. 18 is a diagram illustrating an example of a case where noise occupying a large area is present;

FIG. 19 is an explanatory diagram of error correction using a BCH code.

FIG. 20 is an explanatory diagram when an error correction function is added in the Reed-Solomon coding method.

FIG. 21 is an explanatory diagram when an error correction function is added in the Hamming code system.

[Explanation of symbols]

 1A Printer 2A Scanner 3A Data Input / Output Means 4A Hamming Code Encoder 5A Reed-Solomon Code Encoder 6A Two-Dimensional Image Generation Means 7A Hamming Code Decoder 8A Reed-Solomon Code Decoder 9A Work Memory 10A Relocation Means 10M Relocation Map 11A Keyboard 12A Relocation Map Database 13A Map layout restoration processing means 14A Encoding method combination determination means 15A Pattern detection means 16A BCH code encoder 17A BCH code decoder

Continued on the front page (72) Inventor Taketo Yamaguchi 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Yuji Okada 1006 Kadoma, Kazuma, Kadoma, Osaka Prefecture, Japan Matsushita Electric Industrial Co., Ltd. 1006 Kadoma Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. A first method of adding and encoding at least one type of error correction code to an arbitrary set of bit data.
Encoding means; and a second encoding means for adding at least one type of error correction code to the set of bit data encoded by the first encoding means and encoding the set of bit data; A data encoding device, comprising: mark generation means for generating a two-dimensional image by arranging bit data encoded by the first and second encoding means in a prescribed two-dimensional area in a matrix. 2. The method according to claim 1, wherein said first encoding means is a random encoding means for adding a random error correction code,
2. The data encoding apparatus according to claim 1, wherein said encoding means is burst encoding means for adding a burst error correction code. 3. The method according to claim 2, wherein said first encoding means is burst encoding means for adding a burst error correction code, and said second encoding means is a burst encoding means.
2. The data encoding apparatus according to claim 1, wherein said encoding means is a random encoding means for adding a random error correction code. 4. The data encoding device according to claim 1, further comprising a two-dimensional image printing unit that prints the two-dimensional image on a medium. 5. A rearrangement map indicating an order in which the bit data encoded by the first and second encoding means are rearranged, and the encoded bit data is two-dimensionally arranged based on the rearrangement map. 2. The data encoding apparatus according to claim 1, further comprising a rearrangement unit that rearranges the data on an area and passes the data to the mark generation unit. 6. The rearrangement map for arranging a set of bit data to which the random error correction code is added in one direction of a row or a column in the prescribed two-dimensional area. A data encoding device according to claim 1. 7. The rearrangement map for arranging a set of bit data to which the burst error correction code is added in one direction of a row or a column in the prescribed two-dimensional area. 3. The data encoding device according to claim 1. 8. A relocation map designating means comprising: a relocation map holding means for holding the plurality of types of relocation maps; and a relocation map designation means for selecting a relocation map to be used by the relocation means. 6. The data encoding device according to claim 5, wherein a relocation map in which the direction of the most frequent bit error and the length direction of the set of bit data intersect is selected. 9. A two-dimensional image printed based on bit data encoded by adding at least one type of error correction code by the first encoding means and the second encoding means, A two-dimensional image reading unit that converts the data into bit data, a first decoding unit that performs error correction and decoding on a set of bit data to which the error correction code has been added by the first encoding unit, A data decoding apparatus, comprising: a second decoding corrector that performs error correction and decoding on a set of bit data to which an error correction code has been added by the first coding unit. 10. The first decoding means is a random decoding means for performing error correction and decoding based on a random error correction code, and the second decoding means is an error correction means for performing error correction based on a burst error correction code. 10. The data decoding device according to claim 9, wherein the data decoding device is a burst decoding unit that performs correction and decoding. 11. The first decoding means is a burst decoding means for performing error correction and decoding based on a burst error correction code, and the second decoding means is an error correction means for performing error correction based on a random error correction code. 10. The data decoding device according to claim 9, wherein the data decoding device is a random decoding unit that performs correction and decoding. 12. A method according to claim 1, further comprising: reading the read two-dimensional image at a stage subsequent to the two-dimensional image reading means based on a rearrangement map indicating a rearrangement order after encoding the bit data; 10. The data decoding apparatus according to claim 9, further comprising a map arrangement restoring processing unit for converting the data into a map arrangement.