JP2003346105A - Two-dimensional bar code and method for recording the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large-capacity two-dimensional (2D) bar code card which allows for the recognition of card information by a simple decoding operation during scanning, and a method for decoding the information recorded in the 2D bar code card. <P>SOLUTION: The 2D bar code card is disclosed comprising a carrier and a 2D bar code graphic applied to the carrier. This 2D bar code graphic has an upper edge portion (10), a left edge portion (12), a right edge portion (14) and a bit stream region (16). The upper edge portion (10) is provided along a paper moving direction of the graphic in a first row of a 2D matrix, and the left and right edge portions (12, 14) each have position apertures (20) and are provided along the left and right longitudinal edge portions of the graphic, respectively. The bit stream region (16) is provided between the left and right edge portions (12, 14) below the upper edge portion (10). <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a 2D barcode card and a decoding method thereof. They can be used to record all kinds of codeable information and can be used on different carriers.

[0002]

2. Description of the Related Art A 2D barcode is a kind of graphic and can be recognized by scanning (scan processing). The barcode can be used to record all kinds of coded information, and can be used as a sticker (carrier) such as paper.
Compared to other information recording methods, 2D barcodes are lower cost,
It has advantages such as legibility.

[0003] There are two PDF417 systems and QR systems.
This is the traditional coding method of D barcode. The 2D barcode used in the QR system is a matrix code, and records information by a black and white grid arranged in a matrix state. It can be recognized by three marks such as "times" arranged at the corners of the figure as shown in FIG. The misrecognition rate of the QR matrix code is low. The effective information storage area in the QR matrix figure is large. It is also suitable for acquiring image data with a digital camera.

[0004]

However, the algorithm for recognizing bar codes generated by this coding system is complex. This coding system cannot be employed for image acquisition by scanning. This is because recognition must be started after acquiring all barcodes by scanning.

[0005] The PDF417 coding system is different from the QR coding system. The PDF417 coding system records information at the ratio of the width of adjacent black and white bars. This is why it is called a bar space proportion code. The recognizable pattern shape of this barcode as shown in FIG. 2 is an alternating black and white bar, with bar space proportions provided on both sides of the graphic. PDF4
The 2D barcode generated by the 17 system has a very low false recognition rate, and the algorithm for recognizing the pattern shape of the barcode is simple. It is highly tolerant to false recognition and theoretically allows up to 50% image damage. At the same time, it has great tolerance for linear and non-linear graphic distortion deformation of the graphic, and supports any image acquisition mode. Can decipher when a figure is being scanned. However, coding systems require high quality graphics (high image quality), require relatively little storage, and are expensive to recognize.

An object of the present invention is to provide a large-capacity 2D barcode card, and to recognize card information by a simple decryption operation during a scanning process.

Another object of the present invention is to provide a method for decoding the information of the 2D barcode card.

[0008]

The present invention comprises a carrier,
2D consisting of a 2D barcode figure affixed to the carrier
A bar code card is disclosed. The 2D barcode figure has an upper edge (10), a left edge (12), and a right edge (1).
4) and a bit stream area (16).
The upper edge (10) is provided in the first row of the 2D matrix along the direction of paper movement of the figure, and the left and right edges (12,
14) are provided along the left and right vertical edges of the figure, each having a position hole (20), and the bit stream region (16) is provided with an upper edge (12, 14) between the left and right edges (12, 14). 10). Further, a method of decoding a 2D barcode to read binary information is disclosed. This method allows decoding during the scanning process. The position holes are used as identification and position identification marks. Fast discrimination and simple recognition algorithms are provided.

The present invention discloses a type of 2D barcode card. It is a carrier and 2D attached to the carrier
It contains barcode figures and records information by modules. The 2D barcode graphic includes an upper edge, a left edge, a right edge, and a bit stream area. The upper edge is a first matrix row along the paper movement direction of the graphic. The left edge and the right edge are matrix columns, and position holes are arranged on the left and right sides of the figure. A bitstream area is provided below the upper edge and between the left and right edges.

In one embodiment of the invention, the position holes 20 are white modules, the upper edge 10 is a black module row, the left edge 12 and the right edge 14 are both two black module columns, It consists of alternating black and white columns provided between the two columns.

In another embodiment of the present invention, the module side length is provided by the following equation: R2 / R1 * L> = 4 R1 is the sharpness of the figure printed on the carrier, and R2
Is the sharpness of the image sensor for reading the figure, and L is the side length of a preset module.

In another embodiment of the present invention, bit stream area 1
6 contains several information blocks. Each information block has several matrix rows, and the information block contains an error correction code.

In another embodiment of the invention, blanks are provided to the left of the left edge and to the right of the right edge of the graphic on the carrier.

According to the present invention, a method of decoding a 2D barcode for reading binary information from a 2D barcode attached to a carrier includes the following steps.

A: The upper edge 10 of the figure is detected and the upper edge 1 is detected.
Calculating and storing a gradient of 0; B: detecting the left edge 12 and the right edge 14 of the figure, and based on the gradient of the upper edge 10 obtained in step A, a first pair of position holes 20; Estimating the number of white pixels of the estimated circumscription obtained in step B, and calculating the number of white pixels of the first pair of position holes 2
Calculating the central coordinates of 0; D: calculating the central coordinates of the module between the first pair of position holes 20, and reading out one bit stream information for all the modules of the figure based on the central coordinates; E: before The circumscription of the position hole of the next pair is predicted based on the center coordinates of the position hole 20 of the output pair and the side length of the module, the center coordinates of the position hole are detected and calculated from the circumscription, and the center coordinates of the center hole are calculated. If the detection is not possible, the decoding of the figure is terminated, and if the detection is successful, the next step is performed; F: the central coordinates of the module between the pair of position holes are calculated and stored according to the central coordinates of the pair of position holes, and the center of the position hole is calculated. Reading bitstream information at the corresponding position based on the coordinates; G: all between two rows Calculate the coordinates for the module,
Reading bitstream information of the corresponding module based on the stored center coordinates of the row of modules; H: returning to step E.

According to one feature of the present invention, the number of white pixels is equal to or more than (N-1) * (M-1) and (N + 1) * (M
If +1) or less, it is assumed that there is an effective position hole in the circumscription. N and M are Step C
Is the length of the two sides of the module.

In another aspect of the invention, the total number of rows of the graphic is read in step D, and the decoding process is terminated based on the total number.

In another aspect of the invention, error correction is performed after reading all (S + E) bytes, and S byte correction information is output after error correction.

The 2D barcode card according to the present invention can record all kinds of binary information in a simple matrix code. It is a simpler recognition algorithm compared to the barcode of the QR coding system, and can be decoded during scanning. Position holes are used as identification markers. Barcode information storage area is PD
Wider than that of the F417 coding system. It enhances the storage capacity of the card pasting carrier. The 2D barcode decoding method with a simple matrix code according to the present invention allows decoding during scanning. It uses position holes as identification marks and has fast identification speed and simple identification algorithm.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the present invention will be described in detail with reference to the drawings. Module: A square part that composes a figure. One of the modules is equal to one of the bit data.

Graphic: A combination of barcode symbols, including start / stop symbols, silence area / data symbols and check symbols, required for a particular graphic to form a fully scannable entry.

A scanner equipped with a CIS (contact image sensor) has a light source. The figure obtained by the scanner contains a certain amount of non-linear figure distortion, but has sufficient quality. In order to increase the storage capacity of the carrier, a simple matrix code can be drawn on the 2D barcode card with a simple structure. The 2D barcode card of the present invention includes a carrier and a barcode graphic attached to the carrier. One example of a 2D barcode graphic is shown in FIG. This graphic form is a square. The arrow in FIG. 3 indicates the direction of card movement when scanning a 2D barcode card. A matrix band parallel to the card moving direction is a row of figures, and a matrix band perpendicular to the paper moving direction is a column of figures.

Some same size modules form graphics. The figure has an upper edge 10, a left edge 12, and a right edge 14.
And a bit stream area 16. The upper edge 10 is a row of black modules. The left edge 12 is composed of three columns of modules. The right edge 14 comprises three columns of modules. The three row modules on each side are columns of black modules, and the central row is an alternating arrangement of black and white grids. The white grid is the position hole 20. The bit stream area 16 is the upper edge 1
It is located below 0 and in the middle of the left and right edges 12,14. It is used to record valid information. The edge rows and columns are used for position alignment when reading a figure.

The matrix columns with the position holes 20 shown in FIG. 3 are alternately arranged with one black grid and one white grid, or several black grids and one white grid, or other combinations. It is a thing. All arrangements are within the contemplation of the present invention.

The module of the bit stream area 16 is a data area. All modules record one bit of information, for example, a black grid records "0" and a white grid records "1". The arrangement mode of the data area can be arranged in the up and down direction of a row, or the left and right or right and left of a column.

The graphic contains grids in columns and rows. These grids may be square grids having the same number of pixels in rows and columns. Different numbers of square grids can be provided for rows and columns. The number of grids is determined by the size of the carrier. The length and width of the bit stream area also depend on its size. Error correction codes can be provided to the bitstream as needed. Error correction code is an existing technology.

As described above, a figure obtained by CIS has a small nonlinear distortion. That is, the relative position of the grid is basically fixed, and the position of the grid of the figure can be accurately described by specifying the matrix.

Position holes 20 arranged on a horizontal line on both sides of the figure are designed for that purpose. Once a pair of position holes (one on the left and the other on the right) are identified, the center position of all other modules on the same line is accurately calculated and stored, and bitstream information is obtained directly. . According to the position of the position hole of the preceding pair, the position of the position hole of the next pair can be predicted and calculated, and the position data can be saved. Therefore, the center coordinates of the position hole can be accurately calculated. 2
The center position of all modules between rows and their bitstream information can be simply calculated according to the module's side length. Therefore, by using the position holes as position marks for recognition, the recognition process time is shortened, the algorithm is simplified, and the scanning and the recognition processing are performed in parallel.

A figure obtained by CIS may be distorted. For example, N * N pixels are (N + 1) * (N +
1) It may be distorted into pixels or modules of (N-1) * (N-1) pixels. The error increases relatively as N decreases. When N <= 3, the relative error will reach 30% or 40%. From experience, recognition results are reliable when the side length of the module is 4 scan pixels or more. If the print definition is R1, the design side length of the module is L pixels, and the CIS definition is R2, they can be expressed by the formula R2 / R1 * L> = 4 in order to recognize a figure with high reliability. (All modules average 4 * 4 = 16 pixels).

All position holes are white modules with black grids of the same size around them. Therefore,
There is only one white hole in the specific area. The number of white pixels in this area is counted, and the abscissa and ordinate of each pixel are summed. If the number of white pixels is (N-
1) If between (M-1) and (N + 1) * (M + 1), there is a valid position hole in the circumscription, and N and M in the expression are the two-side lengths of the pixel unit module. It is. The total value divided by the number of white pixels is the center coordinate of the position hole. In one embodiment according to the above principles, a binary computer file is stored on a 2D barcode card and a CIS (Contact Image Sensor) SV252 from SYSCAN Technology Holding.
The 2D barcode graphic is returned to the original binary file by the scanning and reading processing using A8.

The definition of the SV252A8 is 200 DPI. It has 448 image sense units,
These units correspond to a space of 200 DPI.
In consideration of hardware characteristics, in order to effectively increase the recording capability in the same carrier area, a graphic as shown in FIG. 4 was employed.

All modules have a side length of 4 pixels, with 8 pixels being placed on either side of the sensor as extra pixels. The image sensor can correctly infer even if the figure is distorted to some extent. The position holes on both sides and the black module beside the position holes mark 12 pixels, and the remaining 408 pixels make up the bit stream area and are used for recording binary information. All lines have a 408/4 = 12 grid and record 102 bits of binary information.

In order to simplify the calculations for the identification of graphics, the information can be organized in the bitstream area 16 in a predetermined manner. For example, the bitstream area is divided into blocks, and each block has 20 rows. The recording capacity of each block is 102 bits * 20/8
= 255 bytes. 255 to correct the error
The error correction code can be stored using 32 bytes for each byte. This is generated in a read-solom calculation (high-performance error correction calculation), and the actual capacity of all bitstream regions is 223 bytes. The error correction code mainly corrects a 16-bit error in the 255-byte information, and the error correction rate is 6.275. The bit stream area is an integer block (the number of blocks is 1 or more). If the number of information bytes is not enough to fill the last block, it can be filled with predefined bytes and can be ignored after the Reed-Solom error correction process.

Information such as the version number, the byte length of the information, etc., which is specific information of the 2D barcode itself, can be recorded at the start of the bit stream area 16. The version number makes the software distinguish between different information structures. The byte length of the information is used to inform the software of the full length of the graphic immediately after reading the first block and to determine the time to end scanning.

The 2D barcode card of the present invention is read line by line by a graphic scanner. Barcodes can be converted back to binary information with simple matrix code decoding software. The decoding method is shown in FIG.
The method includes the following steps.

1. The upper edge 10 of the figure is detected.
1. calculating and storing a gradient of 0; 2. detecting the left edge 12 and the right edge 14; 3. predicting and calculating the circumscription of the first pair of position holes 20 according to the gradient and the position of the upper edge 10, the position of the left edge 12, and the position of the right edge 14; Count the white pixels of the predicted circumscription of the position hole 20 (the number of white pixels is (N-1) *
If not less than (N-1) and not more than (N + 1) * (N + 1), the circumscription has an effective position hole;
4. N is the side length of the module), calculating the center coordinates of the left position hole and the right position hole, respectively; Calculating and saving all modules in the first line according to the center coordinates of the left and right position holes and the gradient of the upper edge, since the center coordinates of the modules in the row are on a line and the space is equal; . Reading bitstream information from the corresponding position in the graphic based on the center coordinates of all modules in the first line (eg, "black" pixels are binary)
0 "and" white "pixels represent binary" 1 "); 7. Based on the center coordinates of the position hole of the previous pair and the side length of the module, determine the circumscription of the next pair of position holes. 7. Predicting and then detecting and calculating the center coordinates of the position hole (go to next step if successful, end recognition if not successful); Step 5 of center coordinates
8. a step of calculating and storing the same calculation method as above; 9. reading corresponding bitstream information from the graphic based on the central coordinates of all modules; 10. calculating the coordinates of all the modules between the two adjacent rows based on the stored central coordinates (averaging method) and reading out the corresponding bitstream information; Return to step 7.

Since the graphic from the scanner is not exactly the same as the original, a graphic whose luminance varies greatly has a large distortion. The square position hole of the original figure is deformed, and the calculation of the hole becomes complicated. Since the present invention employs a direct calculation method, the calculation for recognizing a simple matrix code is simplified.

If the bit stream area 16 contains an error correction code, for example, if an E byte error correction code is provided every S bytes, the error correction is performed after (S + E) byte information is read. Operate.
If the error correction is successful, S-bit correction information is output. In other cases, the user selects whether to end the recognition process or to continue the recognition process.

These examples are provided as illustrations of the present invention and do not limit the present invention.

[0040]

According to the 2D barcode card and the method for decoding the information of the 2D barcode card according to the present invention, a large-capacity 2D barcode card can be provided, and the card information can be obtained by a simple decoding operation during the scanning process. This has the effect of making it possible to recognize

[0041]

[Brief description of the drawings]

FIG. 1 shows the 2 generated by the QR coding system
It is a D barcode figure.

FIG. 2 is a 2D barcode graphic generated by a PDF417 coding system.

FIG. 3 is a 2D barcode figure generated by the simple matrix code of the present invention.

FIG. 4 shows a 2D barcode card 1 according to the present invention.
It is explanatory drawing which shows the row arrangement of the matrix code in an Example.

FIG. 5 is a flowchart showing a simple code decoding method according to the present invention.

[Explanation of symbols]

10 Upper edge 12 Left edge 14 Right edge 16 bit stream area 20 position holes

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Joji             China Shenzhen Fusha             District, Hongli Road             Number 7002 West First             World Plaza, Office Building             , Room 19 a F term (reference) 5B035 AA00 BB08                 5B072 AA02 CC21 DD01 EE13 HH11

Claims (10)

[Claims] 1. A 2D barcode card comprising a carrier and a 2D barcode graphic attached to the carrier and storing information using a module, the 2D barcode graphic having an upper edge. Part (10) and the left edge (1
2), the right edge (14), and the bit stream area (1
6), wherein the upper edge (10) is provided in a first row of a 2D matrix along the paper movement direction in the 2D barcode graphic, and the left edge (12) and the upper edge (10) are provided. A right edge (14) is provided along the left and right vertical edge of the 2D barcode graphic with a position hole (20), respectively, and the bit stream area (16) is provided on the left and right edge (12, 14) A 2D barcode card, which is located below said upper edge (10). 2. The position hole (20) is a white module, the upper edge (10) is a row of black modules, and the left and right edges (12, 14) are each composed of three columns of modules, each having two columns. Black module and said 2
The 2D barcode card according to claim 1, wherein the 2D barcode card comprises a column module formed by alternately combining dark (black) and light (white) modules between columns. 3. The bit stream area (16) includes a number of information blocks, each information block including a number of rows and an error correction code. 2. The 2D barcode card according to 1. 4. The 2D barcode card according to claim 1, wherein the information in the bit stream area (16) is arranged vertically, horizontally, or right and left. 5. The side length of the module is R2 / R1 * L> =
Where R1 is the sharpness of the barcode print,
3. The 2D barcode card according to claim 1, wherein R2 is a resolution of the scanner, and L is a preset module side length. 6. A 2D bar code according to claim 1, wherein a blank portion is present on the left side of the left edge (12) and on the right side of the right edge (14) of the 2D barcode graphic of the carrier.
D barcode card. 7. A method for decoding a 2D barcode affixed to a carrier and reading binary information, comprising the steps of: A. detecting an upper edge (10) of a graphic and detecting the upper edge (10);
Calculating and storing the gradient of B. detecting the left edge (12) and the right edge (14) of the figure and applying the gradient of the upper edge (10) obtained in step A; E. Predicting the circumscription of the first pair of position holes based on the C. predicting the number of white image pixels of the predicted circumscription obtained in step B; Calculating the central coordinates of 20); D. calculating the central coordinates of the module between the first pair of position holes (20); and, based on the central coordinates, one bit stream information of each module from the graphic. E. predicting the position of the next position hole based on the center coordinates of the position hole (20) of the previous pair and the side length of the module; The central coordinates calculated, stops decryption of the figure to be able to detect the said central coordinate,
If the detection is successful, proceeding to the next step; F. calculating the center coordinates of the module between the position holes of the pair, and reading out the bit stream information of the corresponding position based on the center coordinates; H. A method comprising calculating all the modules in a row and reading out the bitstream information of the corresponding module; and H. returning to step E. 8. In step C, when the number of white figure pixels is (N-1) * (M-1) or more, (N + 1) * (M + 1)
8. The method according to claim 7, further comprising the step of assuming that an effective position hole exists in the circumscription if N and M are side lengths of both sides of the module.
The described method. 9. The method according to claim 7, further comprising the step of reading the total number of rows of the graphic in step D and terminating the decoding process based on the total number of rows. 10. The method according to claim 7, further comprising the step of correcting an error each time (S + E) bytes are read, and outputting correct information of the S bytes when the error correction is completed.