JP4645384B2 - Two-dimensional barcode detection method and detection apparatus - Google Patents

Description

  The present invention relates to an optically readable two-dimensional barcode detection method and detection apparatus.

  In recent years, two-dimensional barcodes in which encoded information is arranged and patterned on a matrix have become widespread as optically readable codes.

  Conventionally, as described in Patent Document 1, for example, in a two-dimensional code in which data represented by a binary code is converted into a cell and arranged as a pattern on a two-dimensional matrix, at least two predetermined points in the matrix are specified. A so-called QR code, which is a so-called QR code, has been proposed in which positioning symbols having a pattern in which the same frequency component ratio can be obtained in scanning lines that cross the center at all angles at positions.

  As a barcode reading method, as described in Patent Document 2, conventionally, at least one of the code words including the start and stop code words of the two-dimensional barcode is detected to detect two barcodes in the image data. It has been proposed to scan the two-dimensional barcode taking into account the orientation of the dimensional barcode symbol and taking that orientation into account.

  Further, the two-dimensional barcode has a large amount of information that can be expressed as compared with the one-dimensional barcode, but the amount of information is still limited. For this reason, when a large amount of information is expressed by a two-dimensional code, it has been proposed to divide the information into a plurality of two-dimensional barcodes (for example, see Non-Patent Document 1).

Here, when reading and decoding a plurality of two-dimensional barcodes formed on a single document, a method of reading and decoding each two-dimensional barcode individually by a dedicated barcode reader, and a multifunction device For example, a method of reading one original document by a method, and detecting and decoding a plurality of two-dimensional barcodes from the obtained image data can be considered.
JP-A-7-254037 JP-A-6-12515 JIS-X-0510 (p22 (5.3.2.7 connection mode))

  However, in the above conventional technique, when a plurality of QR codes formed on a single document are detected by the multi-function peripheral, the positional relationship between the plurality of QR codes and the QR code positioning symbols in portions other than the QR codes. There is a problem that there is a high possibility that a QR code is erroneously detected due to the presence of a part having a frequency distribution similar to the above.

  The present invention has been made to solve the above problems, and an object thereof is to provide a detection method and a detection apparatus for a two-dimensional barcode that can accurately detect a plurality of two-dimensional barcodes included in image data. is there.

In order to solve the above-mentioned problem, the invention according to claim 1 stores in advance light-dark patterns of position element patterns arranged at three corners of the square in order to specify the position and angle of the square two-dimensional barcode. And the step of identifying all image regions that match the light and dark pattern based on the read image data obtained by reading the document, and the center of the image region among all the identified image regions. The figure obtained by connecting the lines is a right-angled isosceles triangle, and the distance between the centers of the image areas is less than a threshold value determined as a ratio to the short side of the read image indicated by the read image data. Detecting a region indicated by the three position element patterns as a two-dimensional barcode as a two-dimensional barcode position element pattern, and three And repeat said step of detecting different combinations of the image area, and includes a second detection step of detecting a plurality of two-dimensional bar code, a.

According to the first aspect of the present invention, in order to specify the position and angle of the square two-dimensional barcode, the light and dark patterns of the position element patterns arranged at the three corners of the square are stored in the storage means in advance. Based on the read image data obtained by reading the original, all image areas that match the light and dark pattern are specified, and among all the specified image areas, a figure obtained by connecting the centers of the image areas with a line is obtained. The position elements of the two-dimensional bar code are three image areas that are right isosceles triangles and whose distance between the centers of the image areas is not more than a threshold value determined as a ratio to the short side of the read image indicated by the read image data. As a pattern, the area indicated by the three position element patterns is detected as a two-dimensional barcode, and the combination of the three image areas is changed. And repeat the serial detection, it detects a plurality of two-dimensional bar code.

That is, paying attention to the shape connecting the three vertices of the square is the isosceles right triangle, Ri obtained graphic Do the isosceles right triangle by connecting the center of the positional element pattern, and the distance between the center of the image area Since two-dimensional barcodes are detected as position element patterns constituting one two-dimensional barcode for three image areas that are equal to or less than a threshold value determined as a ratio to the short side of the scanned image indicated by the scanned image data . Even when a plurality of two-dimensional barcodes are included in the read image data, a plurality of two-dimensional barcodes can be detected with high accuracy.

The present invention may further comprise a step of presetting the size of a right isosceles triangle obtained by connecting the centers with a line, as in the invention described in claim 2 .

Further, as in the third aspect of the invention, it may further include a step of presetting an angle of the read image data of the right isosceles triangle obtained by connecting the centers with a line with respect to the vertical direction.

Furthermore, as in the invention described in claim 4 , the present invention may further include a step of presetting an area where a two-dimensional barcode is present in the read image data.

The present invention may further comprise a step of presetting the number of two-dimensional barcodes included in the read image data, as in the fifth aspect of the invention.

On the other hand, in order to solve the above-mentioned problem, the invention according to claim 6 is arranged such that the light and dark patterns of the position element patterns arranged at the three corners of the square are specified in advance in order to specify the position and angle of the square two-dimensional barcode. Based on the stored storage means, read image data obtained by reading a document, position element pattern specifying means for specifying all image areas that match the light and dark pattern, and the image area specified by the specifying means Of these, the figure obtained by connecting the centers of the three image areas with a line is a right isosceles triangle, and the distance between the centers of the image areas is determined as a ratio to the short side of the read image indicated by the read image data. Three image areas that are equal to or less than the threshold value are set as two-dimensional barcode position element patterns, and the areas indicated by the three position element patterns are Detection means for detecting the dimension bar code, and repeat the detecting means by changing the combination of the three image regions comprises a repeating means for detecting a plurality of two-dimensional bar code, a.

According to the sixth aspect of the invention, since it operates in the same manner as the first aspect of the invention, a plurality of two-dimensional barcodes included in the image data can be detected with high accuracy as in the first aspect of the invention.

  As described above, in the present invention, in order to specify the position and angle of the square two-dimensional barcode, the light and dark patterns of the position element patterns arranged at the three corners of the square are stored in advance in the storage means, Based on the read image data obtained by reading, all the image areas that match the light and dark pattern are specified, and among all the specified image areas, the figure obtained by connecting the centers with a line is a right isosceles triangle. Since each of the three image areas is detected as a two-dimensional barcode position element pattern and the area indicated by the three position element patterns is detected as a two-dimensional barcode, a plurality of two-dimensional barcodes included in the image data are accurately detected. It has an excellent effect that it can be detected well.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is an external view of a multifunction machine 10 according to the present embodiment.

  As shown in FIG. 1, the multifunction machine 10 includes a document reading unit 12, an image forming unit 14, a paper storage unit 16, a tray 18, and an operation unit 20.

  The document reading unit 12 includes a document tray 22, an automatic document feeder 24, and a document discharge tray 26. The automatic document feeder 24 separates the documents set on the document tray 22 one by one, feeds them to the reading position, and then discharges the documents to the document discharge tray 26.

  The reading position is provided with a reading mechanism including a light source, a CCD, and the like. The reading mechanism forms an image of reflected light from the original conveyed to the reading position with a lens or the like as appropriate. Read by CCD.

  The multi-function device 10 acquires image data indicating a document image by the document reading unit 12, performs transmission / reception of data by communication with an external device by a communication unit (not shown), and forms an image based on the image data by the image forming unit 14. Various processes such as scanning, copying, printing, facsimile transmission / reception, etc. can be executed in combination. Instructions input via the operation unit 20 or instructions input from an external device through communication Operates based on.

  When the image is formed by the image forming unit 14, the sheets stored in the sheet storing unit 16 are conveyed one by one to the image forming unit 14 and image data of the document image read by the document reading unit 12, communication with the outside, and the like. An image is formed on a sheet based on the image data and the like input by, and the sheet on which the image is formed is discharged to the tray 18.

  FIG. 2 is a block diagram illustrating an outline of an electrical configuration of the multifunction machine 10. As shown in the figure, the multifunction machine 10 includes a CPU 30 that controls the operation of the entire apparatus. The CPU 30 controls the operation unit 20 and the reading mechanism to receive digital image data. A reading control unit 32 to be acquired, a communication control unit 34 for controlling communication with the outside, an image formation control unit 36 for controlling the image forming unit 14, and a memory 38 are connected.

  The CPU 30 controls the reading control unit 32, the communication control unit 34, and the image formation control unit 36 based on instructions input via the operation unit 20.

  By the way, in this embodiment, when an image showing a two-dimensional barcode is included in the digital image data obtained by the reading control unit 32 via the reading mechanism, the two-dimensional barcode is detected and decoded. ing.

  FIG. 3 is an explanatory diagram showing the structure of a QR code as an example of a two-dimensional barcode. As shown in FIG. 5A, the QR code 50 is formed in a square area, and position element patterns 52 are arranged at three of the four corners of the area. In the figure, the area indicated by white filling other than the position element pattern 52 of the QR code 50 is divided into a plurality of cells, and each cell is an area in which a pattern based on encoded information is arranged. Actually, for example, a plurality of cells smaller than the position element pattern 52 filled with black or white are appropriately arranged.

  As shown in the figure, the three position element patterns 52A, 52B, and 52C constituting one QR code 50 are used to identify the top and bottom of the QR code, and the position element pattern 52 is arranged. Decoding is done so that no corner is in the lower right.

  As shown in FIG. 5B, the position element pattern 52 is a double square, and a light and dark pattern of a straight line passing through the center (for example, a line indicated by a one-dot chain line in the same figure) is 1: 1: 3. Dark-light-dark-light-dark at a ratio of 1: 1. The ratio is stored in advance in a predetermined area of the memory 38, and a margin of ± 0.5 is allowed when actually detected.

  When the CPU 38 detects a pixel line passing through the light and dark pattern of the position element pattern 52 in the image based on the image data, the CPU 38 stores the positions of the first point Q and the last point R that are in contact with the outer edge of the position element pattern 52. To do. Further, the point Q and the point R are sequentially stored for the pixel lines adjacent to the pixel line until all lines crossing the inner dark square are recognized, and the center position of the position element pattern 52 is derived. Further, the coordinates in the image of the center position of the derived position element pattern 52 are stored in the memory 38 as the center coordinates.

  In such a procedure, the position element pattern 52 is detected and the center coordinates are stored for all the pixel lines in the image, and the number and positions of the QR codes 50 are specified using the stored center coordinates. Since there are three center coordinates for one QR code 50, if the number of QR codes 50 included in the image is N, 3N center coordinates are detected.

  Further, when the position of the QR code 50 is specified, the QR code 50 is decoded based on an image showing the QR code 50.

  Hereinafter, the operation of the present embodiment will be described.

  FIG. 5 is a flowchart showing the flow of processing of the QR code detection processing program executed by the CPU 30, and the QR code detection processing according to the present embodiment will be described below with reference to FIG.

  First, in step 200, a position element pattern center coordinate list is created. In the next step 202, the center coordinate of number 1 in the position element pattern center coordinate list is set to X, and in the next step 204, the position element pattern center coordinate list is set to Y. The center coordinate of number 1 in the pattern center coordinate list is set, and then the process proceeds to step 206, and the center coordinate of number 1 in the position element pattern center coordinate list is set in Z.

  As shown in FIG. 4, when four QR codes 50 are included in the read image area E, the center coordinates of at least twelve position element patterns are listed. In order to decode the QR code 50, it is necessary to specify the position and area of each QR code 50 based on the center coordinates.

  Thereafter, the process proceeds to step 208, where it is determined whether X, Y, Z are the same QR code position element pattern 52. If the determination is affirmative, the process proceeds to step 210. The combination of the X, Y, and Z coordinates is stored in a predetermined area of the memory 38, and then the process proceeds to step 212.

  On the other hand, if a negative determination is made in step 208, the process proceeds to step 212 without executing the process of step 210 at this point.

  Here, when the three position element patterns 52A, 52B, and 52C constituting one QR code 50 are connected by a line, a right isosceles triangle having a right angle BAC (see the dotted line in FIG. 3A and FIG. 4). See T1). On the other hand, when the three position element patterns 52 including the position element patterns 52 of different QR codes 50 are connected by lines, as shown by T2 and T3 in FIG.

  Therefore, in the present embodiment, a combination in which a triangle formed by connecting three position element patterns with lines becomes a right isosceles triangle is regarded as a position element pattern 52 constituting the same QR code.

  FIG. 6 shows the flow of the right isosceles triangle determination process executed in step 208 described above. Hereinafter, the right isosceles triangle determination process according to the present embodiment will be described with reference to FIG.

  First, in step 220, the center coordinates set in the above X, Y, and Z are respectively substituted as vertex coordinates of the triangle ABC obtained by connecting the position element patterns 52A, 52B, and 52C with lines, and in the next step 222, Then, the angle θ formed by the straight line AB and the straight line AC is derived, and then the process proceeds to step 224.

  In step 224, it is determined whether or not the angle θ formed is approximately 90 degrees. If the determination is affirmative, it is determined that the angle BAC may be a right-angled isosceles triangle. Then, the process proceeds to step 226.

  The reason why the formed angle θ is approximately 90 degrees is that a positional shift of the center coordinates due to the reading accuracy is assumed, and the allowable range can be set as appropriate.

  On the other hand, if a negative determination is made in step 224, the angle BAC is not a right triangle, and therefore a false determination is made, and step 208 (see FIG. 5) of the QR code detection process is a negative determination.

  In step 226, the distance AB is derived, and in the next step 228, the distance BC is derived, and then the process proceeds to step 230 to determine whether the distance AB = BC. If the determination is affirmative, this triangle ABC is a right isosceles triangle with a right angle BAC, and therefore a True determination is made, and step 208 of the QR code detection process (see FIG. 5) is affirmative.

  In step 212 in FIG. 5, the center coordinate listed next to the center coordinate set as Z at this time is reset as Z, and the process returns to step 206 again. The processing from step 206 to step 212 is repeated 12 times when 12 center coordinates are listed.

  After that, when all the center coordinates listed are set as Z and the processing from step 206 to step 212 is completed, the routine proceeds to step 214 where the center coordinates of Y are changed to the values listed next. Then, the process returns to step 204 again, all the center coordinates are sequentially set as Z, and the processing from step 206 to step 212 is repeated.

  When all the center coordinates listed in this way are set as Y and the processing from step 204 to step 214 is completed, the process proceeds to step 216, where the center coordinates of X are listed next. , The process returns to step 202 again, all the center coordinates are sequentially set as Y, and the processing from step 204 to step 214 is repeated.

  Thereby, it is assumed that all the combinations of center coordinates listed are QR code position element patterns, and if it is determined whether or not the same QR code is configured, the present QR code detection process is performed. finish.

  Accordingly, an image area indicating a QR code is appropriately specified based on the combination of X, Y, and Z stored in the memory 38, and decoding processing is performed based on the image of the image area.

  As described above in detail, according to the present embodiment, the light and dark patterns of the position element patterns arranged at the three corners of the square in order to specify the position and angle of the square two-dimensional barcode are stored in advance. Based on the read image data obtained by reading the document, all image areas that match the light and dark pattern are specified, and the center of all the specified image areas is obtained by connecting with a line. Included in the image data are the three image areas in which the figure formed is a right isosceles triangle as the position element pattern of the two-dimensional barcode and the area indicated by the three position element patterns is detected as the two-dimensional barcode. A plurality of two-dimensional barcodes can be detected with high accuracy.

(Second Embodiment)
In the first embodiment described above, a description has been given of a mode in which all combinations in which a figure formed by connecting the center coordinates of a position element pattern with a line is a right isosceles triangle are detected as combinations of QR code position element patterns. In the second embodiment, a mode in which a combination of QR code position element patterns that satisfy a pre-input size condition is detected will be described.

  In the second embodiment, as a condition for the size of the QR code to be detected, the ratio of the length of one side of the QR code area to the length e of the short side of the read image area is a QR code of N% or less. This can be input in advance, and QR code detection processing is executed based on the conditions.

  Therefore, in the second embodiment, instead of the right-angled isosceles triangle determination process (see FIG. 6) in the first embodiment, a right-angled isosceles triangle determination process considering a QR code size condition. Is executed.

  FIG. 7 shows the flow of the right isosceles triangle determination process taking the QR code size condition into consideration. The right isosceles triangle determination process according to the second embodiment will be described below with reference to FIG.

  First, in step 240, the center coordinates set in the above X, Y, Z are respectively substituted for the vertex coordinates of the triangle ABC obtained by connecting the position element patterns 52A, 52B, 52C with lines, and in the next step 242, The angle θ formed by the straight line AB and the straight line AC is derived, and then the process proceeds to step 244.

  In step 244, it is determined whether or not the angle θ formed is approximately 90 degrees. If the determination is affirmative, it is determined that the angle BAC may be a right-angled isosceles triangle. Then, the process proceeds to step 246.

  The reason why the formed angle θ is approximately 90 degrees is that a positional shift of the center coordinates due to the reading accuracy is assumed, and the allowable range can be set as appropriate.

  On the other hand, if a negative determination is made in step 244, the angle BAC is not a right triangle, and therefore a false determination is made, and step 208 (see FIG. 5) of the QR code detection process is a negative determination.

  In step 246, the distance AB is derived, and in the next step 248, it is determined whether or not the derived distance AB is smaller than the threshold value m (N% of e). The process proceeds to step 250 to derive the distance BC, and then proceeds to step 252.

  In step 252, it is determined whether or not the derived distance BC is smaller than the threshold value m (N% of e). If the determination is affirmative, the process proceeds to step 254 to determine whether distance AB = BC. Determine whether or not. If the determination is affirmative, the triangle ABC is a right isosceles triangle whose angle BAC is a right angle and whose isosceles is equal to or less than the threshold value m, so a True determination is made and step 208 (QR code detection processing) (See FIG. 5) is affirmative.

  On the other hand, when a negative determination is made in any one of step 248, step 252, and step 254, the triangle ABC is not a right-angled isosceles triangle with the angle BAC being a right angle and the isosceles being equal to or less than the threshold value m. False determination is made, and step 208 (see FIG. 5) of the QR code detection process is negative.

  As described above in detail, according to the second embodiment, the light and dark patterns of the position element patterns arranged at the three corners of the square in order to specify the position and angle of the square two-dimensional barcode are determined. Based on the read image data obtained by reading the document and stored in advance in the storage unit, all the image areas that match the light and dark pattern are specified, and the center of all the specified image areas is a line. Since the three image areas in which the figure obtained by the connection is a right-angled isosceles triangle are each detected as a two-dimensional barcode position element pattern, and the area indicated by the three position element patterns is detected as a two-dimensional barcode, image data A plurality of two-dimensional barcodes included in can be detected with high accuracy.

Further, according to the second embodiment, the size of a right isosceles triangle obtained by connecting the centers with a line is set in advance, and three images that become a right isosceles triangle satisfying the size condition are set. Since each region is a position element pattern of a two-dimensional barcode, a plurality of two-dimensional barcodes included in the image data can be detected with higher accuracy.
(Third embodiment)
In the second embodiment described above, a mode has been described in which a combination of QR code position element patterns that satisfy a size condition input in advance is detected. In the third embodiment, the size of a QR code is detected. Instead, a mode in which a combination of QR code position element patterns whose rotation angle with respect to the read image area satisfies a predetermined condition will be described.

  Here, as shown in FIGS. 8A to 8D, the obtained read image varies depending on the orientation of the original with respect to the reading direction R. FIG. 6A shows a case where the top of the original image matches the top of the read image. In this case, the QR code 50 included in the read image is read without being rotated.

  In FIG. 8B, the document is read by being rotated 90 degrees with respect to the reading direction R, and the QR code 50 included in the read image is also read by being rotated 90 degrees.

  Similarly, in FIG. 8C, the document is read 180 degrees rotated with respect to the reading direction R, and the QR code 50 included in the read image is also read 180 degrees rotated. In FIG. 8D, the document is read by being rotated by −90 degrees with respect to the reading direction R, and the QR code 50 included in the read image is also read by being rotated by −90 degrees. .

  As described above, normally, in the MFP 10, the QR code 50 may be read by being rotated in units of 90 degrees, but it is considered that the QR code 50 may be read at other rotation angles such as 30 degrees and 100 degrees. Hateful.

  Therefore, in the third embodiment, a combination of the position element patterns 52A, 52B, and 52C whose rotation angle with respect to the read image area E is any one of (A) to (D) is detected.

  FIG. 9 shows the flow of a right isosceles triangle determination process in consideration of the rotation angle condition of the QR code. Hereinafter, the right isosceles triangle determination process according to the third embodiment will be described with reference to FIG.

  First, in step 260, the center coordinates set in the above X, Y, Z are respectively substituted for the vertex coordinates of the triangle ABC obtained by connecting the position element patterns 52A, 52B, 52C with lines, and in the next step 262, The rotation angle λ of the triangle ABC is derived.

  Here, the rotation angle λ is a vector derived using the reference vector and the vertex coordinates actually set, where the vector AB connecting the vertex A and the vertex B in the case shown in FIG. It corresponds to the angle formed with AB.

  In the next step 264, an angle difference P between the rotation angle that the QR code 50 can take and the actual rotation angle λ is derived, and then the process proceeds to step 266. In the present embodiment, since the rotation angle that the QR code 50 can take is set to be in units of 90 degrees, the remainder when the rotation angle λ is divided by 90 degrees is set as the angle difference P. For example, when the rotation angle λ is 120 degrees, the angle difference P is 30 degrees.

  In step 266, it is determined whether or not the angle difference P is smaller than a predetermined value α (3 degrees in the present embodiment). If the determination is affirmative, the process proceeds to step 268. Note that the predetermined value α can be set in accordance with the accuracy of the automatic document feeder 24 or the like, or the displacement that generally occurs when the user sets the document at the reading position, taking into account the displacement with respect to the document reading direction. A value obtained by an experiment using an actual machine or a computer simulation based on the specifications of the actual machine can be applied.

  On the other hand, if a negative determination is made in step 266, it is determined that the coordinates set as the coordinates of the apex of the triangle ABC are not the same QR code 50 position element patterns 52A, 52B, 52C, and a False determination is made. In step 208 (see FIG. 5) of the QR code detection process, a negative determination is made.

  That is, first, it is determined whether or not the rotation angle satisfies the condition, and the number of combinations of vertices A, B, and C for executing the process of determining whether or not the triangle is in detail is reduced, so the processing time is shortened. Thus, the QR code can be detected efficiently.

  In step 268, the angle θ formed by the straight line AB and the straight line AC is derived, and thereafter, the process proceeds to step 270.

  In step 270, it is determined whether or not the angle θ formed is approximately 90 degrees. If the determination is affirmative, it is determined that the angle BAC may be a right-angled isosceles triangle. Then, the process proceeds to step 272.

  The reason why the formed angle θ is approximately 90 degrees is that a positional shift of the center coordinates due to the reading accuracy is assumed, and the allowable range can be set as appropriate.

  On the other hand, if a negative determination is made in step 270, the angle BAC is not a right triangle, and therefore a false determination is made, and step 208 (see FIG. 5) of the QR code detection process is a negative determination.

  In step 272, the distance AB is derived, and in the next step 274, the distance BC is derived, and thereafter, the process proceeds to step 276.

  In step 276, it is determined whether or not the distance AB = BC. If the determination is affirmative, the triangle ABC is a right isosceles triangle with a right angle BAC, and thus a True determination is made, and step 208 (see FIG. 5) of the QR code detection process is an affirmative determination.

  On the other hand, if a negative determination is made in step 276, the triangle ABC is not a right isosceles triangle, although the angle BAC is a right angle, it becomes a false determination, and step 208 of the QR code detection process (see FIG. 5). Is negative.

  As described above in detail, according to the present third embodiment, the light and dark patterns of the position element patterns arranged at the three corners of the square in order to specify the position and angle of the square two-dimensional barcode. Based on the read image data obtained by reading the document and stored in advance in the storage unit, all the image areas that match the light and dark pattern are specified, and the center of all the specified image areas is a line. Since the three image areas in which the figure obtained by the connection is a right-angled isosceles triangle are each detected as a two-dimensional barcode position element pattern, and the area indicated by the three position element patterns is detected as a two-dimensional barcode, image data A plurality of two-dimensional barcodes included in can be detected with high accuracy.

  In addition, according to the third embodiment, an angle with respect to the vertical direction of the read image data of the right-angled isosceles triangle obtained by connecting the centers with a line is set in advance, and a right-angled isosceles triangle that satisfies the angle condition Each of the three image areas is a position element pattern of a two-dimensional barcode, so that a plurality of two-dimensional barcodes included in the image data can be detected with higher accuracy.

  Note that the configuration (see FIGS. 1 and 2) of the MFP 10 according to each of the above embodiments is merely an example, and it is needless to say that the configuration can be appropriately changed without departing from the gist of the present invention.

  Moreover, the flow of processing according to the present embodiment (see FIGS. 5 to 7 and FIG. 9) is also an example, and can be appropriately changed without departing from the gist of the present invention.

  For example, in the present invention, an area where a two-dimensional barcode exists in the read image data may be set in advance. In this case, since only the read image data in the set area needs to be processed, the processing time can be shortened.

  Further, the number of two-dimensional barcodes included in the read image data may be set in advance. In this case, it is possible to end the processing when the right isosceles triangle is detected by the number of preset two-dimensional barcodes, and the processing time can be shortened.

  Furthermore, by configuring the QR code so that it can be set by appropriately combining the size, rotation angle, existence area, and number of conditions, two-dimensional barcode detection can be performed with higher accuracy and speed.

  Regarding conditions such as the size, rotation angle, existence area, and number of QR codes, the user can input the conditions according to the document to be read when reading the document via the operation unit 20. It can also be stored and set in advance in the memory 38 or the like of the multifunction machine 10.

  In the first to third embodiments, the embodiment in which the present invention is applied to the multifunction device 10 has been described. However, the present invention is not limited to the multifunction device 10, and general copying machines, scanners, and the like can be used. Needless to say, the present invention can be applied to a typical image reading apparatus.

1 is an external view of a multifunction machine according to an embodiment. 1 is a block diagram illustrating an outline of an electrical configuration of a multifunction machine according to an embodiment. It is explanatory drawing which shows the structure of QR Code as an example of a two-dimensional barcode. FIG. 6 is a schematic diagram illustrating a state where four QR codes are included in a read image area. It is a flowchart which shows the flow of a process of a QR code detection process program. It is a flowchart which shows the flow of the right isosceles triangle determination process performed with the detection processing program which concerns on 1st Embodiment. It is a flowchart which shows the flow of the right isosceles triangle determination process in consideration of the size condition of the QR code executed by the detection processing program according to the second embodiment. FIG. 6 is an explanatory diagram illustrating a state of a read image and a QR code corresponding to a reading direction R of a document. It is a flowchart which shows the flow of the right isosceles triangle determination process in consideration of the conditions of the rotation angle of QR code performed with the detection processing program which concerns on 3rd Embodiment.

Explanation of symbols

10 MFP 12 Document Reading Unit 14 Image Forming Unit 16 Paper Storage Unit 18 Tray 20 Operation Unit 22 Document Tray 24 Automatic Document Feeder 26 Document Discharge Tray 30 CPU
32 Reading control unit 34 Communication control unit 36 Image formation control unit 38 Memory 50 QR code 52 Position element pattern

Claims (6)

In order to specify the position and angle of the square two-dimensional barcode, the light and dark patterns of the position element patterns arranged at the three corners of the square are stored in advance in the storage means,
Identifying all image areas that match the light and dark pattern based on read image data obtained by reading a document;
Of all the specified image areas, the figure obtained by connecting the centers of the image areas with a line is a right isosceles triangle, and the distance between the centers of the image areas is indicated by the read image data. A first detection step of detecting, as a two-dimensional barcode, a region indicated by the three position element patterns, each of three image regions that are equal to or less than a threshold value determined as a ratio to the two-dimensional barcode;
And repeat said step of detecting different combinations of three image areas, a second detection step of detecting a plurality of two-dimensional bar code,
2D barcode detection method comprising: Two-dimensional bar code detection method of claim 1 Symbol placement and further comprising a step of presetting a size of right-angled isosceles triangle obtained by connecting the center with a line. Claim 1 or claim 2 Symbol placement of the two-dimensional bar code and further comprising a step of previously setting the angle to the vertical direction of the read image data of the right-angled isosceles triangle obtained by connecting the center with a line Detection method. The method for detecting a two-dimensional barcode according to any one of claims 1 to 3 , further comprising a step of presetting a region where the two-dimensional barcode is present in the read image data. The method for detecting a two-dimensional barcode according to any one of claims 1 to 4 , further comprising a step of presetting the number of two-dimensional barcodes included in the read image data. Storage means for preliminarily storing light and dark patterns of position element patterns arranged at the three corners of the square in order to specify the position and angle of the square two-dimensional barcode;
Position element pattern specifying means for specifying all image regions that match the light and dark pattern based on read image data obtained by reading a document;
Of the image areas specified by the specifying means, a figure obtained by connecting the centers of the image areas with lines is a right-angled isosceles triangle, and a read image in which the distance between the centers of the image areas is indicated by the read image data, respectively. Detecting means for detecting three image areas that are equal to or less than a threshold defined as a ratio to the short side of each as a two-dimensional barcode position element pattern, and detecting a region indicated by the three position element patterns as a two-dimensional barcode;
And repeat the detecting means by changing the combination of the three image regions, and repeating means for detecting a plurality of two-dimensional bar code,
A two-dimensional bar code detection device comprising:

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