JP5428935B2 - Two-dimensional barcode reader, program, two-dimensional barcode and medium - Google Patents

Description

  The present invention relates to a two-dimensional barcode reader, a program, a two-dimensional barcode, and a medium.

  Techniques have been proposed for evaluating whether a two-dimensional barcode whose image has deteriorated due to distortion, expansion and contraction, etc. can be decoded (for example, Patent Documents 1 and 2).

JP-A-9-128469 Japanese Patent No. 2946945

  An object of the present invention is to improve the decoding accuracy of a two-dimensional barcode.

The two-dimensional barcode reader according to the present invention includes an acquisition unit that acquires an image including a two-dimensional barcode, and an auxiliary pattern that is in a predetermined region from the image acquired by the acquisition unit, distortion detection pattern formed by arranging a plurality of patches of a predetermined position and shape a distortion detection pattern for detecting the distortion of the image, a telescopic detection pattern for detecting the expansion and contraction of the code image previously determined An expansion / contraction detection pattern formed by arranging a plurality of patches of a predetermined position and shape, or a density fluctuation detection pattern for detecting density fluctuation of a code image, so that the density gradually decreases from one to the other. an auxiliary pattern detecting means for detecting the auxiliary pattern including at least one of the formed density variation detection pattern, the region The reference pattern storage means for storing the auxiliary pattern to be set as a reference pattern, and the auxiliary pattern detected by the auxiliary pattern detection means and the reference pattern are compared to detect the fluctuation amount of the image of the two-dimensional barcode. It is characterized by comprising fluctuation amount detection means and correction means for correcting the image of the two-dimensional barcode included in the image acquired by the acquisition means in accordance with the fluctuation amount detected by the fluctuation amount detection means.

  Further, the auxiliary pattern detecting means detects auxiliary patterns provided in both the horizontal direction and the vertical direction with respect to a rectangular code image.

The program according to the present invention includes an acquisition unit that acquires an image including a two-dimensional barcode, an auxiliary pattern in a predetermined region from the image acquired by the acquisition unit, and a distortion of the code image position determined in advance in a telescopic detection pattern for detecting multiple arrayed strain detection pattern formed by the patch of a predetermined position and shape a distortion detection pattern, the expansion and contraction of the code image to detect And an expansion / contraction detection pattern formed by arranging a plurality of patches of a shape or a density fluctuation detection pattern for detecting a density fluctuation of a code image, wherein the density gradually decreases from one to the other. auxiliary pattern detecting means for detecting an auxiliary pattern that includes at least one of the density variation detection pattern, the auxiliary pattern A fluctuation amount detecting means for detecting a fluctuation amount of the image of the two-dimensional barcode by comparing the auxiliary pattern detected by the detection means and a reference pattern of the auxiliary pattern set in the region, the fluctuation amount detection According to the fluctuation amount detected by the means, it functions as a correction means for correcting the image of the two-dimensional barcode included in the image acquired by the acquisition means.

The two-dimensional barcode according to the present invention is a distortion detection pattern for detecting distortion of a code image and is formed by arranging a plurality of patches having a predetermined position and shape in a predetermined area in the vicinity . Distortion detection pattern , expansion / contraction detection pattern for detecting expansion / contraction of the code image, which is formed by arranging a plurality of patches having predetermined positions and shapes, or density for detecting variation in the density of the code image It is characterized in that it is arranged in combination with at least any two density fluctuation detection patterns formed so that the density gradually decreases as one goes from one to the other .

  Further, the area is provided in a quiet zone, and a module for forming each pattern is provided at a position not adjacent to a code image area.

  Further, the area is provided in both a horizontal direction and a vertical direction with respect to a rectangular code image.

  A medium according to the present invention is characterized in that the two-dimensional barcode of any one of the above inventions is added.

  According to the first and third aspects of the invention, the two-dimensional barcode can be corrected to improve the decoding accuracy.

  According to the second and sixth aspects of the invention, it is possible to detect two-dimensional distortion, expansion / contraction, concentration fluctuation, and the like.

  According to the fourth and seventh aspects of the invention, the decoding accuracy of the two-dimensional barcode can be improved.

  According to the fifth aspect of the present invention, the detection pattern can be arranged near the two-dimensional barcode.

It is the block block diagram which showed one Embodiment of the two-dimensional barcode reader which concerns on this invention. It is a hardware block diagram of the computer which forms the two-dimensional barcode reader in this Embodiment. It is the figure which showed an example of the arrangement | positioning area | region of the auxiliary pattern handled in this Embodiment. It is the figure which showed the example of arrangement | positioning of the auxiliary pattern with respect to the arrangement | positioning area | region in this Embodiment. It is the flowchart which showed the decoding process of QR code in this Embodiment. It is the figure which showed an example of the distortion detection pattern used in this Embodiment. It is the figure which showed the auxiliary pattern and the reference | standard pattern which have the distortion detected in this Embodiment up and down. It is the figure which arranged and showed the auxiliary pattern which has the expansion-contraction detected in this Embodiment up and down the reference | standard pattern. It is the figure which showed the auxiliary pattern which has the density fluctuation | variation detected in this Embodiment along with the upper and lower sides of the reference pattern. It is the figure which showed the auxiliary pattern which has the density fluctuation | variation detected in this Embodiment along with the other reference pattern. In this Embodiment, it is the figure which showed the example of arrangement | positioning of the auxiliary pattern arrange | positioned in the arrangement area | region of an auxiliary pattern.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a two-dimensional bar code reader according to the present invention. FIG. 2 is a hardware configuration diagram of a computer forming the two-dimensional barcode reader 20 according to the present embodiment.

  In FIG. 2, the computer can be realized by a general-purpose hardware configuration that has existed before. That is, the computer forming the two-dimensional barcode reader 20 includes a CPU 1, a ROM 2, a RAM 3, an HDD controller 5 connected to a hard disk drive (HDD) 4, and a mouse 6 provided as input means as shown in FIG. An input / output controller 9 for connecting a keyboard 7 and a display 8 provided as a display device, respectively, and a network controller 10 provided as a communication means are connected to an internal bus 11.

  Returning to FIG. 1, the two-dimensional barcode reader 20 in the present embodiment includes an image acquisition unit 21, a QR code detection unit 22, an auxiliary pattern detection unit 23, an image correction unit 24, a decoding unit 25, and a reference pattern storage unit 26. have. In this embodiment, a case where a QR code is handled as a two-dimensional barcode will be described as an example. The image acquisition unit 21 acquires an image including a QR code. The QR code detection unit 22 detects and extracts a QR code image from the acquired image. The auxiliary pattern detection unit 23 detects an auxiliary pattern from the QR code image. The auxiliary pattern will be described later. The reference pattern storage unit 26 is not affected (changed) by an auxiliary pattern serving as a reference for detecting the variation amount of the detected auxiliary pattern, that is, distortion or expansion / contraction embedded in the image together with the QR code. Information on auxiliary patterns (hereinafter referred to as “reference patterns”) is stored. The information related to the reference pattern includes the image, arrangement, shape, size, and the like of the reference pattern. The image correction unit 24 is provided as a fluctuation amount detection unit and a correction unit, detects a fluctuation amount of the QR code image by comparing the detected auxiliary pattern with a reference pattern, and the acquisition unit according to the detected fluctuation amount The image of the QR code included in the image acquired by the above is corrected. The decoding unit 25 extracts the encoded data by decoding the corrected QR code.

  The components 21 to 25 in the two-dimensional barcode reader 20 are realized by a cooperative operation of a computer that forms the two-dimensional barcode reader 20 and a program that operates on the CPU 1 mounted on the computer. The reference pattern storage unit 26 is realized by the HDD 4 in the two-dimensional barcode reader 20. Alternatively, the two-dimensional barcode reader 20 may be provided on an external computer having a storage unit so as to acquire necessary information directly from the computer or via a network.

  Further, the program used in this embodiment can be provided not only by communication means but also by storing it in a computer-readable recording medium such as a CD-ROM or DVD-ROM. The program provided from the communication means or the recording medium is installed in the computer, and various processes are realized by the CPU of the computer sequentially executing the installation program.

  FIG. 3 is a diagram showing an example of an auxiliary pattern arrangement region handled in the present embodiment. FIG. 3 also includes an enlarged view of the main part of the QR code. FIG. 3 shows a QR code to which an auxiliary pattern is applied and an auxiliary pattern arrangement area 34. Usually, an area where nothing is displayed, which is generally called a quiet zone 31, is provided around the QR code so that it can be distinguished from other information on the medium to which the QR code is added. The quiet zone 31 has a width of at least 4 modules and forms a margin. One module is a QR code drawing reference size. In this embodiment, the quiet zone 31 is effectively used, and an auxiliary pattern arrangement region 34 having a width of at least one module is provided in this portion. The auxiliary pattern arrangement region 34 needs to be provided so as not to contact the QR code image inside the quiet zone 31 and so as not to contact other images outside the quiet zone 31. Therefore, in the case of the quiet zone 31 having a width of 4 modules, the auxiliary pattern arrangement area 34 may be provided with a width of 2 modules. As shown in FIG. 3, in the present embodiment, the module is located at a position two modules away from the QR code image portion 32 and one module away from the outer edge 33 of the quiet zone 31. A pattern arrangement area 34 is provided.

  FIG. 4 is a diagram illustrating an arrangement example of auxiliary patterns. In FIG. 3, the auxiliary pattern arrangement area 34 is shown as a maximum area so as to surround the entire QR code. However, as illustrated in FIG. It may be partially provided on at least one of the vertical side or the horizontal side, that is, the vertical direction or the horizontal direction. 4 shows an example in which the auxiliary pattern is arranged on one side of the QR code, the second stage shows an example in which the auxiliary pattern is arranged on two sides of the QR code, and the third stage shows a case in which the auxiliary pattern is arranged on three sides of the QR code. It is an example. And in the lowest level, an example arranged at the entire circumference, an example arranged at one corner by connecting regions arranged at a part of the side, an example arranged at one part of the side sandwiching the side and the side ,It is shown. The auxiliary pattern arrangement region 34 may be set with various patterns, for example, not only the example shown in FIG.

  Next, QR code decoding processing according to the present embodiment will be described with reference to the flowchart shown in FIG.

  The image acquisition unit 21 acquires an image including a QR code (step 110). This may be a read image of a medium such as a paper document by a scanner (not shown), or image data scanned and formed in advance may be read from the HDD 4 or acquired via a network. Subsequently, the QR code detection unit 22 detects a QR code from the images acquired by the image acquisition unit 21 and extracts an image of the QR code (step 120). In a two-dimensional bar code such as a QR code, since a position detection pattern is embedded in a code image at a predetermined position, the position of the QR code is specified by detecting this from the image. An existing technique may be used to detect the QR code. When the position of the QR code is specified, the auxiliary pattern detection unit 23 detects the auxiliary pattern from the auxiliary pattern arrangement region. In the case of the present embodiment, the setting position of the auxiliary pattern is determined in advance so as to be within the arrangement area of the auxiliary pattern included in the quiet zone existing around the QR code image. In this embodiment, it is assumed that the positional relationship between the reference point in the QR code and the auxiliary pattern is determined in advance. Therefore, the auxiliary pattern detection unit 23 specifies the reference point from the QR code, and specifies the position of the auxiliary pattern based on the positional relationship from the reference point. The reference point may be, for example, the center coordinates of the QR code position detection pattern, or may be determined according to other rules. Alternatively, a reference point in the auxiliary pattern may be specified from the reference point obtained from the QR code, and the auxiliary pattern may be detected based on the positional relationship from the reference point in the auxiliary pattern. In the present embodiment, as described above, the auxiliary pattern of the arrangement as shown in FIG. 4 is detected in the quiet zone (step 130).

  When the auxiliary pattern is detected from the acquired image, the image correction unit 24 reads the reference pattern from the reference pattern storage unit 26 and compares the detected reference pattern with the detected auxiliary pattern. A variation amount of the auxiliary pattern is detected (step 140). The deviation (fluctuation) between the reference pattern and the detected auxiliary pattern is the spread of images such as image reading using a device with low reading accuracy, image reading with a handy scanner, the state of the original glass of the scanner, and a booklet whose reading surface cannot be flattened. It can be generated by reading a document. The variation amount is represented by a rectangular QR code distortion, lateral expansion / contraction, density variation, and the like. A method for detecting this variation will be described in detail later.

  When detecting the fluctuation amount, the image correction unit 24 corrects the QR code image by performing distortion correction (affine transformation or the like), expansion / contraction, and density correction at the time of multi-value scanning based on the fluctuation amount (step 150). Here, only the QR code is corrected because it is only necessary to be able to decode the QR code, but the entire acquired image may be corrected.

  Then, the decoding unit 25 decodes the QR code from the corrected image (step 160). The decoding method is based on the QR code specification. Since the QR code has already been detected, the result is used. If the coordinates of the QR code are changed as a result of the image correction, the coordinate information is also corrected.

  Hereinafter, detection of the auxiliary pattern and the variation amount in the present embodiment will be described.

  In the present embodiment, three functions of distortion measurement, vertical / horizontal expansion / contraction measurement, and density fluctuation measurement are provided as functions of the auxiliary pattern.

  FIG. 6 is a diagram showing an example of a distortion detection pattern used in the present embodiment. The distortion detection pattern is an auxiliary pattern used to detect distortion of the QR code image. In the case of the present embodiment, since the auxiliary pattern is arranged with a width of one module in the quiet zone, a black patch of 1 × 1 module is arranged in a predetermined arrangement area of the auxiliary pattern, and one module according to the timing pattern of the QR code. Are arranged at equal intervals to form a distortion detection pattern. In FIG. 6, the black patches are arranged in the horizontal direction, but it goes without saying that they are arranged in the vertical direction in the arrangement area in the vertical direction.

  FIG. 7 is a diagram in which the detected auxiliary pattern (referred to as “detection pattern” in the figure) and the reference pattern are arranged one above the other. Although the reference pattern is drawn in the quiet zone of the QR code, the detection pattern may be distorted for the reason described above. As illustrated in FIG. 7, when distortion occurs, the black patches constituting the detection pattern are not detected side by side. Therefore, in the present embodiment, the center coordinates of each black patch of the detection pattern are obtained, and the alignment of the center coordinates is compared with the alignment (usually a straight line) of the center coordinates of the black patches included in the reference pattern. The variation is detected by. In this case, the fluctuation amount may be calculated by a variance or the like using a well-known statistical process. Note that the reference pattern using the black patches arranged side by side as shown in FIG. 7 detects only the distortion in the horizontal direction. Therefore, in order to detect the distortion in the vertical direction, the reference pattern using the black patches arranged in the vertical direction is used as the auxiliary pattern. It may be arranged in the arrangement area 34. In the present embodiment, the variation amount is detected using the center coordinates of the black patch. However, for example, another reference point such as the upper left corner of the black patch may be used.

  Note that the black patches shown in FIG. 6 may be formed by 1 × n modules (n is a positive integer) or may not necessarily be arranged at regular intervals. Also, the color need not be limited to black. However, the position and shape (size) of the black patch in the distortion detection pattern may be obtained in advance and registered in the reference pattern storage unit 26.

  Next, an auxiliary pattern for measuring the vertical / horizontal expansion / contraction will be described. This auxiliary pattern is an auxiliary pattern for detecting the expansion / contraction of the code image. This expansion / contraction detection pattern is the same as that shown in FIG. You may form with a pattern. That is, the expansion / contraction detection pattern and the distortion detection pattern may be used together. The auxiliary pattern when used in combination is referred to as a “distortion expansion / contraction detection pattern”. FIG. 8 is a diagram showing a reference pattern and detection patterns arranged above and below the reference pattern. The detection pattern (shrinkage) can be formed by using, for example, a scanner that causes the read image to be hazy, but is detected as a pattern having a smaller width than the reference pattern. On the other hand, the detection pattern (expansion) can be formed by using, for example, a scanner that darkens the read image, but is detected as a wider pattern than the reference pattern. In this case, the fluctuation amount may be calculated as a fluctuation amount represented by a ratio of side lengths or the like. In addition, since the reference pattern based on the black patches arranged side by side as shown in FIG. 8 detects only the expansion and contraction in the horizontal direction, in order to detect the expansion and contraction in the vertical direction, the reference pattern based on the black patches arranged in the vertical direction is used as the auxiliary pattern. It may be arranged in the arrangement area 34. The black patches may be formed by 1 × n modules (n is a positive integer) or may not necessarily be arranged at a constant interval. Also, the color need not be limited to black. The position and shape (size) of the black patch in the expansion / contraction detection pattern may be obtained in advance and registered in the reference pattern storage unit 26.

  FIG. 9 and FIG. 10 are diagrams showing examples of density fluctuation detection patterns used in the present embodiment. 9 and 10 also show distortion expansion / contraction detection patterns 41 and 43 arranged at both ends of the density fluctuation detection patterns 42 and 44, respectively. The density fluctuation detection pattern is an auxiliary pattern used for detecting the density fluctuation of the code image. In the case of this embodiment, two types of density fluctuation detection patterns are provided.

  Among these, the density variation detection pattern 42 is a gradation type patch as shown in FIG. 9, and a black patch of 1 × n module is adopted, and pixel values in this black patch are changed from one to the other. The gradient is added so that the density gradually decreases, that is, the pixel value gradually decreases. In the case of a gradation type density fluctuation detection pattern, if the detection pattern is binarized, for example, the darker detection pattern has a longer black portion than the reference pattern, and the lighter detection pattern has a lower density than the reference pattern. The black part becomes shorter. You may detect this length as a fluctuation amount. Note that the color of the patch need not be limited to black.

  As shown in FIG. 10, the other density fluctuation detection pattern 44 has 1 × 1 modules arranged at equal intervals of one module, that is, arranged in a state where black patches are separated, and from one to the other (see FIG. 10 from right to left), the density is graded so that the density of the black patch gradually decreases continuously, that is, the pixel value of the black patch gradually decreases.

  In the case of the separation type density fluctuation detection pattern, for example, when the detection pattern is binarized, the detection pattern with a high density has a larger number of detections of black patches than the reference pattern, and the detection pattern with a low density is a reference pattern. Compared to less. The number of detected black patches may be detected as a fluctuation amount. The black patches may be formed by 1 × n modules (n is a positive integer) or may not necessarily be arranged at a constant interval. Also, the color need not be limited to black.

  It should be noted that the horizontal long density fluctuation detection pattern as shown in FIG. 9 and the reference pattern with the horizontal black patches as shown in FIG. 10 detect only the horizontal density fluctuation, so that the vertical density fluctuation is detected. In order to detect this, a density variation detection pattern that is long in the horizontal direction or a reference pattern that is formed by vertically arranged black patches may be arranged in the auxiliary pattern arrangement region 34. The position and pixel value of the black patch in the density variation detection pattern may be obtained in advance and registered in the reference pattern storage unit 26.

  As described above, the strain detection pattern and the expansion / contraction detection pattern may be used together. However, the density variation detection pattern can be used as another detection pattern under conditions such as when the density is high. It is.

  FIG. 11 is a diagram illustrating an example of the arrangement of auxiliary patterns arranged in the auxiliary pattern arrangement area. In FIG. 11, the arrangement area for the distortion expansion / contraction detection pattern is indicated by a dotted line, and the arrangement area for the density fluctuation detection pattern is indicated by a solid line. FIG. 11A shows an example in which a density fluctuation detection pattern is arranged at a corner where a QR code position detection pattern is located, and a distortion expansion / contraction detection pattern is arranged between the density fluctuation detection patterns. On the other hand, FIG. 11B shows the reverse pattern. FIG. 11C is an example in which a distortion expansion / contraction detection pattern and a density fluctuation detection pattern are arranged vertically and horizontally, respectively. This is suitable when it is desired to prepare a continuous arrangement region. FIG. 11D shows an example in which only a distortion expansion / contraction detection pattern is arranged. This is suitable when a binary print scan with very little density fluctuation is assumed. This is also effective for short QR codes. Conversely, only the density fluctuation detection pattern may be arranged. The two-dimensional barcode reader 20 reads the QR code on which at least one auxiliary pattern is arranged in this way. FIG. 11E shows an example in which density variation detection patterns are arranged on only one side in the vertical and horizontal directions. FIG. 11F shows an example in which the functions are minimized in detecting the amount of variation. The density variation detection pattern is partially applied to the vertical and horizontal sides, and the distortion is expanded and contracted partially to the horizontal sides. This is an example in which detection patterns are arranged.

  In the present embodiment, a quiet zone has been described as an example of the predetermined area near the QR code in which the auxiliary pattern is arranged as described above. However, the auxiliary pattern need not be limited to this quiet zone. For example, it may be placed anywhere within a document image provided with a QR code. Of course, in order to recognize a variation close to the distortion or the like that the QR code receives, it is preferable that the QR code is arranged in the vicinity of the QR code.

  Further, in this embodiment, a reference point is set in the QR code in order to detect the arrangement of the auxiliary pattern. The reference point need not be limited to the QR code, and may be arranged anywhere within the document image provided with the QR code. Of course, it is preferable that it is in the vicinity of the QR code where the auxiliary pattern is arranged or in the QR code.

  As described above, the QR code is arranged by combining at least any two of the strain detection pattern, the expansion / contraction detection pattern, and the density variation detection pattern. In this embodiment, several patch arrangement examples are shown for each auxiliary pattern. However, this patch arrangement pattern includes a QR code version (model number), a known condition using the QR code, for example, a QR code. What is necessary is just to set according to each characteristic, such as an image to add, a printer which prints QR code, or a scanner which reads QR code.

  In the present embodiment, the QR code is described as an example of the two-dimensional barcode, but the present invention is not limited to this.

  1 CPU, 2 ROM, 3 RAM, 4 Hard disk drive (HDD), 5 HDD controller, 6 Mouse, 7 Keyboard, 8 Display, 9 Input / output controller, 10 Network controller, 11 Internal bus, 20 Two-dimensional barcode reader, 21 image acquisition unit, 22 QR code detection unit, 23 auxiliary pattern detection unit, 24 image correction unit, 25 decoding unit, 26 reference pattern storage unit.

Claims (7)

An acquisition means for acquiring an image including a two-dimensional barcode;
An auxiliary pattern in a predetermined region from the image acquired by the acquisition means, which is a distortion detection pattern for detecting distortion of the code image, and a plurality of patches having predetermined positions and shapes are arranged. Detects variations in the density of a stretch detection pattern or code image that is formed by arranging a plurality of patches having predetermined positions and shapes, and is a stretch detection pattern for detecting the formed strain detection pattern and the stretch of the code image. An auxiliary pattern detection means for detecting an auxiliary pattern including at least one of density fluctuation detection patterns formed so that the density gradually decreases from one to the other .
Reference pattern storage means for storing auxiliary patterns set in the region as reference patterns;
A fluctuation amount detecting means for detecting a fluctuation amount of an image of a two-dimensional barcode by comparing the auxiliary pattern detected by the auxiliary pattern detection means and the reference pattern;
Correction means for correcting the image of the two-dimensional barcode included in the image acquired by the acquisition means according to the fluctuation amount detected by the fluctuation amount detection means;
A two-dimensional bar code reader.   2. The two-dimensional barcode reader according to claim 1, wherein the auxiliary pattern detecting unit detects auxiliary patterns provided in both a horizontal direction and a vertical direction with respect to a rectangular code image. . Computer
An acquisition means for acquiring an image including a two-dimensional barcode;
An auxiliary pattern in a predetermined region from the image acquired by the acquisition means, which is a distortion detection pattern for detecting distortion of the code image, and a plurality of patches having predetermined positions and shapes are arranged. Detects fluctuations in the density of an expansion / contraction detection pattern or code image formed by arranging a plurality of patches having predetermined positions and shapes, which are detection patterns for detecting the expansion and contraction of the formed distortion detection code and code image. An auxiliary pattern detection means for detecting an auxiliary pattern including at least one of density fluctuation detection patterns formed so that the density gradually decreases from one to the other .
A fluctuation amount detection means for detecting a fluctuation amount of the image of the two-dimensional barcode by comparing the auxiliary pattern detected by the auxiliary pattern detection means with a reference pattern of the auxiliary pattern set in the region;
Correction means for correcting the image of the two-dimensional barcode included in the image acquired by the acquisition means according to the fluctuation amount detected by the fluctuation amount detection means;
Program to function as. A distortion detection pattern for detecting distortion of a code image in a predetermined area in the vicinity, which is formed by arranging a plurality of patches having predetermined positions and shapes, and detecting expansion and contraction of the code image from one to the other a density variation detection pattern for detecting the variation in the concentration of the telescopic detection pattern at a pre-determined position and shape of the telescopic detection pattern or code image patches are formed by a plurality arranged for A two-dimensional barcode characterized by being arranged in combination with at least any two of density variation detection patterns formed so that the density gradually decreases with time .   5. The two-dimensional barcode according to claim 4, wherein the area is provided in a quiet zone at a position where a module for forming each pattern is not adjacent to an area of a code image.   The two-dimensional barcode according to claim 4, wherein the region is provided in both a horizontal direction and a vertical direction with respect to a rectangular code image.   A medium to which the two-dimensional barcode according to any one of claims 4 to 6 is added.