JP5988228B2 - Two-dimensional code, image reading apparatus, image reading method, program, and storage medium - Google Patents

Description

  The present invention particularly relates to a two-dimensional code suitable for reading a distorted two-dimensional code, an image reading apparatus, an image reading method, a program, and a storage medium.

  Conventionally, a two-dimensional code that can store a lot of information in a narrow area, such as a QR code (registered trademark), is often used. This two-dimensional code is used not only as a means for providing information through the Internet or the like, but also as a means for reading the information instantaneously when used for a product or a ticket. In recent years, a system has been proposed in which a barcode is attached to a garbage bag and an operator reads it with a handy terminal.

  As described above, the two-dimensional code is used for many purposes. However, if the two-dimensional code is distorted, information may not be sufficiently read. Therefore, Patent Documents 1 and 2 disclose a method of extracting each region by extracting sampling points from a read image when the two-dimensional code is uniformly distorted as a whole.

JP 2010-44586 A Japanese Patent Laid-Open No. 2004-362053 JP 2009-151700 A

  However, when the two-dimensional code of the garbage bag is read in a state where the garbage is jammed, the two-dimensional code is often locally distorted or non-uniformly distorted. In the methods described in Patent Documents 1 and 2, It is difficult to read information sufficiently from a two-dimensional code.

  An object of the present invention is to make it possible to easily read information when a two-dimensional code is distorted in view of the above-described problems.

  The two-dimensional code of the present invention is a two-dimensional code having a plurality of cells. When a two-dimensional code image having a distorted shape is generated by imaging the two-dimensional code, the distorted shape 2 Control points for specifying a position for reading information from the dimension code image are given to the boundary of the cell at a predetermined cycle.

The image reading apparatus of the present invention acquires a two-dimensional code image by capturing a two-dimensional code in which a control point for specifying a position to read information is added to a boundary of the cell at a predetermined cycle together with a plurality of cells. Information from the two-dimensional code image corrected by the distortion correcting means, the distortion correcting means for correcting by the shape deformation method starting from the control point in the two-dimensional code image generated by the imaging means, And a decoding means for reading.
Another feature of the image reading apparatus according to the present invention is that, together with a plurality of cells, a two-dimensional code in which a control point for specifying a position to read information is given to the boundary of the cells at a predetermined cycle. An imaging unit that captures an image to obtain a two-dimensional code image, an area analysis unit that analyzes an area of each cell that constitutes the two-dimensional code in the two-dimensional code image captured by the imaging unit, and the imaging unit When a two-dimensional code image having a distorted shape is acquired by imaging the two-dimensional code, it is analyzed by the region analyzing unit based on the control points in the two-dimensional code image captured by the imaging unit. A decoding means for specifying a sampling position of the cell and reading information from the specified position .

According to the image reading method of the present invention, a two-dimensional code image is obtained by imaging a two-dimensional code in which a control point for specifying a position for reading information is given to a boundary of the cell at a predetermined cycle together with a plurality of cells. Information from the two-dimensional code image corrected in the distortion correction step, a distortion correction step of correcting by a shape deformation method starting from the control point in the two-dimensional code image generated in the imaging step, And a decoding step for reading.
Another feature of the image reading method of the present invention is that, together with a plurality of cells, a two-dimensional code in which a control point for specifying a position to read information is given to the boundary of the cells at a predetermined cycle is provided. In the imaging step of capturing and obtaining a two-dimensional code image, in the two-dimensional code image captured in the imaging step, a region analysis step of analyzing the region of each cell constituting the two-dimensional code, and in the imaging step When the two-dimensional code is captured and a two-dimensional code image having a distorted shape is acquired, the two-dimensional code image is analyzed in the region analysis step based on the control points in the two-dimensional code image captured in the imaging step. A decoding step of specifying a sampling position of the cell and reading information from the specified position .

  A program according to the present invention causes a computer to execute each step of the image reading method described above.

  The storage medium of the present invention stores the program.

  According to the present invention, even when the two-dimensional code is partially distorted or when the two-dimensional code is non-uniformly distorted, information can be read starting from the control point.

In an embodiment of the present invention, it is a figure explaining signs that an image reading device is photographing a two-dimensional code given to a garbage bag which flows into a belt. 1 is a block diagram illustrating a hardware configuration example of an image reading apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating an exemplary functional configuration of an image reading apparatus according to an embodiment of the present invention. In an embodiment of the present invention, it is a figure showing an example of a black cell and a white cell divided in a two-dimensional code. In an embodiment of the present invention, it is a figure showing an example of a two-dimensional code to which a control point or a line was given. In an embodiment of the present invention, it is a figure showing an example of a two-dimensional code image after distortion was amended by the inverse FFD method. It is an enlarged view which shows a position detection element pattern. It is a figure which shows the position detection element pattern in a two-dimensional code. It is a figure which shows the position where the model number information in a two-dimensional code is stored. It is a figure which shows the position detection element pattern and alignment pattern in a two-dimensional code. It is an enlarged view showing an alignment pattern. It is a figure which shows the upper left part of a two-dimensional code. It is a figure which shows the lower right part of a two-dimensional code. In an embodiment of the present invention, it is a figure showing a position of a sampling grid when not performing distortion correction. 5 is a flowchart illustrating an example of a processing procedure for reading a two-dimensional code in the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, an image reading apparatus that reads a QR code (registered trademark) as a representative example of a two-dimensional code will be described.

FIG. 1 is a diagram for explaining a state in which the image reading apparatus 100 captures an image of a two-dimensional code attached to a trash bag 101 flowing through a belt 102.
As shown in FIG. 1, the camera 103 of the image reading apparatus 100 faces the belt 102 side and photographs the two-dimensional code of the garbage bag 101. Then, the image reading apparatus 100 reads the two-dimensional code to determine the contents of the dust packed in the dust bag 101, and the dust bag 101 flowing through the belt 102 is automatically sorted based on the determination result. A sensor 104 is attached to the upper part of the belt 102 facing the camera 103. When the sensor 104 detects the garbage bag 101, the information is input to the image reading apparatus 100 through the communication line 105. Then, imaging (reading) of the two-dimensional code is started on the image reading apparatus 100 side. Then, the determination result of the contents of the garbage is transferred to the automatic sorting device 106 that sorts the garbage bag 101 via the communication line 105.

  Although details will be described later in this embodiment, a two-dimensional code to which control points or lines of a color different from that of the two-dimensional code as shown in FIG. Even when the two-dimensional code is distorted, information can be easily read.

FIG. 2 is a block diagram illustrating a hardware configuration example of the image reading apparatus 100 according to the present embodiment.
In FIG. 2, a CPU 201 controls the entire image reading apparatus 100, reads a program stored in the ROM 203 when necessary, develops it in the RAM 202, and executes processing according to the present embodiment. The image input device 204 corresponds to the camera 103 shown in FIG. 1, and includes an image sensor such as a CCD, an A / D conversion circuit that converts an analog signal into a digital signal, and predetermined image processing for a captured image. The signal processing circuit etc. which performs are included.

  The input device 205 is an operation member that inputs commands in response to user operations. The storage device 206 is a hard disk, for example, for storing data. The image display device 207 is a liquid crystal display, for example, and displays a warning such as a reading error or displays a two-dimensional code being photographed in real time. A network interface card (NIC) 208 is an interface for exchanging data with other information devices via the LAN 210. The main bus 209 is a bus for connecting the above-described components.

  FIG. 3 is a block diagram illustrating a functional configuration example of the image reading apparatus 100 according to the present embodiment. FIG. 15 is a flowchart illustrating an example of a processing procedure for reading a two-dimensional code in the present embodiment. Hereinafter, a procedure for reading a two-dimensional code having distortion will be described with reference to FIGS. 3 and 15.

  First, in step S1501 in FIG. 15, the imaging unit 301 captures a two-dimensional code using the image input device 204 in FIG. 2 and inputs the image data. In step S1502, the region analysis unit 302 analyzes the region of each cell in the two-dimensional code (hereinafter referred to as a two-dimensional code image) related to the input image data. For example, when the two-dimensional code is distorted, each cell does not become a square, so it is necessary to analyze the distorted cell region. As shown in FIG. 4, the area analysis unit 302 divides the areas of the black cell 401 and the white cell 402.

  In addition, the region analysis unit 302 analyzes the two-dimensional code image and determines whether or not a control point or a line, which will be described later, is given to the two-dimensional code. If no control point or line is assigned, a process of assigning a control point or line to the two-dimensional code image is performed as the process of the next step S1503. On the other hand, if control points or lines have been added to the two-dimensional code in advance, the processing in step S1503 is omitted, and processing for correcting distortion of the two-dimensional code image is performed.

  Next, in step S1503, the control point assigning unit 303 assigns a control point or a line, which becomes a reference necessary for converting a cell to a square by a method described later from a distorted two-dimensional code, to the two-dimensional code image. . Further, the boundary lines of the individual cells analyzed by the region analysis unit 302 are given to the two-dimensional code image.

  Hereinafter, a two-dimensional code to which control points or lines are assigned will be described. FIGS. 5A to 5D are diagrams showing examples of two-dimensional codes to which lines are added, and FIGS. 5E and 5F are two-dimensional to which control points are given. It is a figure which shows the example of a code | cord.

  In the present embodiment, in order to correct a two-dimensional code image in a distortion correction unit 304 described later, it is necessary to acquire control points (or lines). Therefore, since the black cell 401 and the white cell 402 are divided by the region analysis unit 302, information on the row and column of each cell can be acquired. Therefore, in the case of the example as shown in FIGS. 5A to 5C, lines are provided to divide the rows and columns at a predetermined cycle, and FIGS. 5E and 5F are applied. In the case of the example shown, control points are given to the corners of the cell at a predetermined period.

  Note that the positions of the control points can be any density as long as they do not interfere with the function of the two-dimensional code. When the period is shortened the most, the control points are given to the four corners of each cell by giving a line to the boundary region of each cell. If the period is shortened, the accuracy of distortion correction is improved, but the calculation takes a lot of time, so the density is changed in some cases. Further, instead of a predetermined cycle, lines and control points may be given by an irregular arrangement as shown in FIG. Furthermore, it is preferable that the control points or lines have a color different from that of the two-dimensional code so that the control points or lines can be distinguished from the cells constituting the two-dimensional code.

  In addition, the cell itself may be colored as a control point. In this case, when converting into binary data of white and black, it is necessary that the color be converted into the same color (white or black) as the original two-dimensional code. Further, by using the error correction function of the two-dimensional code, decoding is possible even when the color is converted to a color different from that of the original two-dimensional code. As a technique for coloring a cell so that decoding is possible, for example, the technique described in Patent Document 3 can be used.

  In step S1504, the distortion correction unit 304 corrects the distorted two-dimensional code so as to be readable in the two-dimensional code image. When lines are given, a grid is formed by each line, and the grid points can be considered as control points. Therefore, the same calculation method can be used as when control points are assigned. Even when a part of a line cannot be recognized and a lattice point cannot be obtained, the position of the lattice point can be estimated based on a part of the recognized line. As a calculation method, various methods such as FFD (Free-form deformation) and DDM method can be used to deform the shape of the object. For example, it can correct | amend by applying reversely the FFD method represented by the following formula | equation (1).

Here, s and t indicate values obtained by normalizing the x and y components of the coordinate values of the control points before correction from 0 to 1, and P _ij indicates the corrected coordinates of each control point. Show. i and j respectively indicate row and column numbers at the control points, and X _FFD indicates the coordinates of the control points before correction. Further, _a C _b is a binomial coefficient. FIG. 6 shows an example of a two-dimensional code image after distortion is corrected by the FFD method. In this embodiment, the distortion is corrected by the FFD method. However, the distortion may be corrected by performing affine transformation for each rectangular area including four control points.

  In step S <b> 1505, the image reading unit 305 performs processing for reading information from the two-dimensional code image corrected by the distortion correction unit 304. A procedure for decoding (reading) information from the two-dimensional code image will be described below.

  First, the light and dark state in the two-dimensional code image is referred to. Specifically, first, an intermediate reflection value between the maximum reflection value and the minimum reflection value in the two-dimensional code image is set as a threshold value, and the two-dimensional code image is set to a set of dark and bright pixels at the boundary of the intermediate reflectance. Convert to

  Next, the position of the position detection pattern at the corner of the two-dimensional code image is obtained. The position detection pattern of the two-dimensional code is composed of the same position detection element patterns arranged at three of the four corners. As shown in FIG. 7, the cell width of each position detection element pattern is composed of dark-light-dark-light-dark columns having a ratio of 1: 1: 3: 1: 1. In this algorithm, the tolerance of these widths is 0.5 (that is, a range of 0.5 to 1.5 for one cell and 2.5 to 3 for 3 cells. .5 range).

  Next, when an area candidate is detected, the positions of points A and B where the pixel lines in the two-dimensional code image are in contact with the outer edge of the position detection element pattern are stored as shown in FIG. Then, this process is repeated for adjacent pixel lines in the two-dimensional code image until all lines crossing the dark square inside the position detection element pattern with respect to the x-axis direction in the two-dimensional code image are recognized. . Next, similarly to the y-axis direction in the two-dimensional code image, adjacent pixel lines in the two-dimensional code image are recognized until all lines crossing the dark square inside the position detection element pattern are recognized. Repeat this process for.

  Next, the center position of the position detection element pattern is obtained. Specifically, a line passing through the center of the point A and the point B on the outermost pixel line crossing the dark square inside the position detection element pattern with respect to the x-axis direction is obtained. Similarly, a line is also obtained in the y-axis direction, and the intersection of the two lines is set as the center position of the position detection element pattern. The center position is obtained for the other two position detection element patterns by the above procedure.

Next, in the symbols in the two-dimensional code image, the direction of the symbol is obtained by analyzing the center coordinates of the position detection element pattern that recognizes the upper left position detection element pattern and the rotation angle of the symbol. Then, as shown in FIG. 8, the distance D between the centers of the upper left position detection element pattern and the upper right position detection element pattern and the widths W _UL and W _UR of the two position detection element patterns crossing the maximum width of the symbol. Ask.

Next, the nominal X dimension of the symbol is calculated by the following equation (2).
X = (W _UL + W _UR ) / 14 Formula (2)

Next, the model number V of the temporary symbol is calculated by the following equation (3).
V = [(D / X) -10] / 4 Formula (3)

If the model number of the temporary symbol is 6 or less as a result of the calculation of Expression (3), this value is used as the model number of the symbol. On the other hand, when the model number of the temporary symbol is 7 or more, the model number information is decoded as follows. First, the cell size CP _UR is calculated by the following equation (4).
CP _UR = W _UR / 7 Equation (4)

Next, auxiliary lines AB and AC are obtained from the center positions A, B and C of the three position detection element patterns shown in FIG. Based on the parallel lines of the auxiliary lines, the center coordinates of the position detection element pattern, and the cell size _CPUR , a sampling grid is set for the center of each cell in the area of the model number information 1 shown in FIG. The binary data 0 or 1 is determined from the light or dark state on the sampling grid.

Based on the extended BCH error correction applied to the model number information 1, if there is an error, it is detected and corrected to determine the symbol model number. On the other hand, when an error exceeding the error correction capability is detected, the same calculation is performed for the pattern width W _DL of the lower left position detection element pattern, and the model number information 2 is decoded by the same method.

A sampling grid is set based on the position detection element pattern for the symbol of model number 1 where no alignment pattern exists. On the other hand, as shown in FIG. 10, for the symbols having a model number of 2 or more in which an alignment pattern exists, the center coordinates of each alignment pattern are obtained by the following procedure, and a sampling grid is set. First, the cell size CP _UL is obtained from the width W _{UL of} the upper left position detection element pattern P _{UL by} the following equation (5).
CP _UL = W _UL / 7 ... Formula (5)

Next, the center coordinates A position detection pattern P _UL of the upper left of FIG. 9, the auxiliary line AB, AC of parallel lines, and based on the size CP _UL cell tentative center coordinates of the alignment pattern P1 and P2 Ask for. Then, as shown in FIG. 11, the white square outlines of the alignment patterns P1 and P2 are scanned from the temporary center coordinate pixels, respectively, and the actual center coordinates (X _i , Y _j ) are calculated.

Next, the center coordinate of the upper left position detection pattern P _UL, from the actual center coordinates of the alignment pattern P1 and P2, to estimate the temporary center coordinates of the alignment pattern P3. Then, the actual center coordinates of the alignment pattern P3 are obtained by the same procedure.

Next, as shown in FIG. 12, the distance L _x between the center coordinates of the alignment patterns P2 and P3 and the distance L _y between the center coordinates of the alignment patterns P1 and P3 are obtained. Then, module pitches CP _x and CP _y are obtained by using the center module interval AP of the alignment pattern by the following equation (6).
CP _x = L _x / AP
CP _y = L _y / AP ··· formula (6)

Similarly, the distance L _x ′ between the center coordinates of the upper left position detection element pattern _{PUL and} the center coordinates of the alignment pattern P1, and the center coordinates of the upper left position detection element pattern _{PUL and} the center coordinates of the alignment pattern P2 The distance L _y ′ is obtained. Then, module pitches CP _x ′ and CP _y ′ on the upper and left sides of the upper left area of the symbol are obtained by the following equation (7).
_{CP x '= L x' /} {( column coordinate of the center of the alignment pattern P1) - (column coordinate of the center of the position detection element patterns P _UL of the upper left)}
_{CP y '= L y' /} {( the center of the row coordinate of the alignment pattern P2) - (center of the row coordinate of the position detection element patterns P _UL of the upper left)} Equation (7)

Next, a sampling grid that covers the upper left area of the symbol is set based on the module pitches CP _x , CP _x ′, CP _y , CP _y ′ of each side of the upper left area of the symbol. By the same procedure, the module pitch is obtained for the upper right area and the lower left area of the symbol, and the sampling grid is set.

Next, as shown in FIG. 13, for the alignment pattern P6 in the lower right region of the symbol, the module pitch CP _x 'CP _y ' is obtained from the alignment patterns P3, P4 and P5. Then, the module pitch CP _x 'CP _y', auxiliary line passing through the center of the alignment pattern P3, P4, auxiliary line passing through the center of the alignment pattern P3, P5, and the temporary center coordinates from the center coordinates thereof aligned pattern Is estimated. Then, the sampling grid in the lower right area of the symbol is set in the same manner as described above. Further, in an unprocessed area such as the center of a two-dimensional code, a sampling grid is set by the same procedure as that in the lower right area of the symbol.

  As described above, when the sampling grid is set in all regions of the symbol, decoding is performed according to the following procedure. First, image pixels (cells) on each intersection of grid lines are sampled, and either light or dark is determined based on a threshold value. Then, a bit matrix is constructed with dark pixels as 1 of binary data and bright pixels as 0 of binary data.

Next, the format information is decoded from the area adjacent to the upper left position detection element pattern _PUL , and the error correction level and mask pattern information applied to the symbol is obtained. When an error exceeding the error correction capability of the format information is detected, the format information is decoded from the area adjacent to the upper right position detection element pattern _PUR or the lower left position detection element pattern P _DL , and the error correction level and mask are detected. Get pattern information.

  Next, the mask process is canceled by performing an exclusive OR operation (XOR operation) on the mask pattern in the symbol encoding area, and the symbol character (data) indicating the data and error correction is decoded. Here, decoding is performed by reversing the procedure of the mask process applied in the encoding process. Then, the code word of the symbol is obtained according to the arrangement rule.

  Next, the blocked code word strings are rearranged by reversing the interleaving process in accordance with the symbol model number and error correction level. Then, according to the error detection and correction decoding procedure, the rejection error and the substitution error up to the maximum correction capacity with respect to the symbol model number and the error correction level are corrected. The original message is then restored by combining the data blocks in the column.

  Further, the data bit string is further divided into segments starting with a mode indicator. The length is determined by the character number indicator following the mode indicator. Then, each segment is decoded according to the rules of the mode being applied. Information is decoded from the two-dimensional code image by the procedure as described above.

  Returning to the description of FIG. 3, the result output unit 306 outputs the decoded information to the automatic sorting device 106 via the communication line 105.

  In the above description, an example in which distortion is corrected by the distortion correction unit 304 when the two-dimensional code is distorted has been described. However, information can be decoded without correcting distortion. When a line is added to the boundary region of each cell by the control point adding unit 303, or when a line is added to the boundary region of each cell in advance in the two-dimensional code, the image reading unit 305 is shown in FIG. In this way, the sampling grid is set at the intersection of lines connecting the midpoints of the sides of the grid. Then, in accordance with the information analyzed by the region analysis unit 302, the format information is decoded from the region adjacent to the position detection element pattern, and the information is decoded from the encoding region. When the control point interval is larger than the cell unit, the module pitch is determined from the control point coordinates, and the sampling grid is set.

  As described above, according to the present embodiment, when a two-dimensional code attached to a garbage bag or the like is read, a control point that serves as a reference necessary for converting a distorted two-dimensional code into a square by a method described later. Or give a line. Then, distortion is corrected starting from a lattice point formed by a control point or line. As a result, even when the two-dimensional code is greatly distorted, such as when the two-dimensional code of the garbage bag is read in a state where the garbage is jammed, the information can be sufficiently read.

  In addition, when control points or lines that are necessary for conversion into a square are preliminarily assigned to the two-dimensional code, distortion is started from the lattice points formed by these control points or lines. It can be corrected.

(Other embodiments according to the present invention)
In the above-described embodiment, an example has been described in which one image reading device reads the two-dimensional code of the garbage bag flowing on the belt in order to separate the waste with an automatic sorting device at a waste collection center or the like. On the other hand, a plurality of image reading devices may be arranged, the results decoded by the respective image reading devices may be totaled, and the automatic sorting device may sort the garbage bags based on the totaled results. In this case, the automatic sorting apparatus may summarize the aggregation results and adopt the most decryption results, and one server may aggregate the decryption results from the respective image reading apparatuses, and the most decryption results. May be sent to the automatic sorting apparatus as a final result. In either case, the decoding result can be reflected in the automatic sorting device with higher accuracy. Further, a two-dimensional code may be attached to a plurality of surfaces of the garbage bag.

  In the above-described embodiment, an example in which a waste collection center is assumed has been described. However, an image reading apparatus is mounted on a garbage collection vehicle, and a garbage bag with a two-dimensional code is loaded on the garbage collection vehicle. It can also be applied to an example in which a two-dimensional code is read and the garbage is separated. In this case, it is possible to eliminate the need for the operator to sort the garbage visually.

  Further, each unit constituting the image reading apparatus and each step of the image reading method in the embodiment of the present invention described above can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  Further, the present invention can be implemented as, for example, a system, apparatus, method, program, or recording medium. Specifically, the present invention may be applied to a system including a plurality of devices. The present invention may be applied to an apparatus composed of a single device.

  The present invention includes a case where a software program (in the embodiment, a program corresponding to the flowchart shown in FIG. 15) for realizing the functions of the above-described embodiments is directly or remotely supplied to the system or apparatus. This includes the case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Examples of the recording medium for supplying the program include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. Further, there are MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, there is a method of connecting to a homepage on the Internet using a browser of a client computer. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  As another method, the program of the present invention is encrypted, stored in a recording medium such as a CD-ROM, distributed to users, and encrypted from a homepage via the Internet to users who have cleared predetermined conditions. Download the key information to be solved. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. Furthermore, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  As another method, the program read from the recording medium is first written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of the program, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

DESCRIPTION OF SYMBOLS 301 Image pick-up part 302 Area | region analysis part 303 Control point provision part 304 Distortion correction | amendment part 305 Image reading part 306 Result output part

Claims (10)

A two-dimensional code comprising a plurality of cells,
When the two-dimensional code is imaged and a two-dimensional code image having a distorted shape is generated, control points for specifying a position to read information from the two-dimensional code image having the distorted shape are set at a predetermined cycle. A two-dimensional code characterized by being attached to a cell boundary.   The two-dimensional code according to claim 1, wherein the control point has a color different from that of the plurality of cells.   The said control point is a point used as the starting point which correct | amends the distorted shape in order to specify the position which reads information from the two-dimensional code image of the distorted shape. Two-dimensional code.   The control point is a point for specifying a sampling position of each of the plurality of cells in order to specify a position for reading information from the distorted two-dimensional code image. Or the two-dimensional code of 2. An imaging means for acquiring a two-dimensional code image by imaging a two-dimensional code in which a control point for specifying a position to read information is given to the boundary of the cell at a predetermined cycle together with a plurality of cells;
Distortion correcting means for correcting by a shape deformation technique starting from the control point in the two-dimensional code image generated by the imaging means;
An image reading apparatus comprising: a decoding unit that reads information from the two-dimensional code image corrected by the distortion correction unit. An imaging means for acquiring a two-dimensional code image by imaging a two-dimensional code in which a control point for specifying a position to read information is given to the boundary of the cell at a predetermined cycle together with a plurality of cells;
In the two-dimensional code image picked up by the image pickup means, area analysis means for analyzing the area of each cell constituting the two-dimensional code;
When the two-dimensional code is captured by the imaging unit and a two-dimensional code image having a distorted shape is acquired , the region analysis is performed based on the control points in the two-dimensional code image captured by the imaging unit. An image reading apparatus comprising: decoding means for specifying a sampling position of the cell analyzed by the means and reading information from the specified position. An imaging step of acquiring a two-dimensional code image by imaging a two-dimensional code in which a control point for specifying a position to read information is given to a boundary of the cell at a predetermined cycle together with a plurality of cells;
A distortion correction step of correcting by a shape deformation technique starting from the control point in the two-dimensional code image generated in the imaging step;
And a decoding step of reading information from the two-dimensional code image corrected in the distortion correction step. An imaging step of acquiring a two-dimensional code image by imaging a two-dimensional code in which a control point for specifying a position to read information is given to a boundary of the cell at a predetermined cycle together with a plurality of cells;
In the two-dimensional code image imaged in the imaging step, an area analysis step for analyzing the area of each cell constituting the two-dimensional code;
When the two-dimensional code is captured in the imaging step and a distorted two-dimensional code image is acquired , the region analysis is performed based on the control points in the two-dimensional code image captured in the imaging step. An image reading method comprising: a decoding step of specifying a sampling position of the cell analyzed in the step and reading information from the specified position. A program for causing a computer to execute each step of the image reading method according to claim 7 or 8 . A computer-readable storage medium storing the program according to claim 9 .

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