JP7200793B2 - 2D code reader - Google Patents

Description

The technology disclosed in this specification relates to a two-dimensional code reader.

As shown in Patent Document 1, a two-dimensional code for reading information recorded in a two-dimensional code configured by arranging a plurality of bright cells and a plurality of dark cells in a two-dimensional matrix is known. ing. A two-dimensional code reader is used to read information recorded in this type of two-dimensional code. Such a two-dimensional code reader normally decodes information recorded in the two-dimensional code on the basis of an image pickup section that picks up an image of the two-dimensional code and a code image representing the two-dimensional code picked up by the image pickup section. and a control unit for performing.

Japanese Patent No. 2938338

In the technique of Patent Document 1, it is originally planned that only one type of information is recorded in one two-dimensional code to be read. That is, in the technique of Patent Document 1, when a specific two-dimensional code having a specific cell configuration is read by a two-dimensional code reader, the decoding result output as the read result is the specific two-dimensional code each time. is intended to be specific information pre-recorded in the

However, in recent years, one of a plurality of cells constituting one two-dimensional code is intentionally displayed in an intermediate color between a bright color and a dark color, or is intentionally displayed in a bright color portion and a dark color portion. It has been confirmed that special two-dimensional codes, which are divided into special cells and displayed, are used for fraudulent purposes, for example. When such a special two-dimensional code is read by a two-dimensional code reader, the special cell is Sometimes it is read as a dark cell, and sometimes it is read as a light cell. Then, depending on whether the special cell is read as a dark-colored cell or read as a bright-colored cell, two different decoding results may be output. As a result, when the special two-dimensional code is read, problems such as the output of decoding results not intended by the user of the two-dimensional code reader (for example, the URL of a harmful site, etc.) may occur.

This specification provides a technology that can determine whether or not a read two-dimensional code is a special two-dimensional code that can output two different decoding results depending on the reading conditions. .

The two-dimensional code reader disclosed in this specification includes an imaging unit that captures a two-dimensional code configured by arranging a plurality of bright cells and a plurality of dark cells in a two-dimensional matrix, and a control unit. , is equipped with The control unit includes a decoding unit that decodes information recorded in the two-dimensional code based on the code image representing the two-dimensional code captured by the imaging unit, and a decoding unit that decodes information recorded in the two-dimensional code based on the code image captured by the imaging unit. a first judging unit for judging whether or not an error correction process has been performed in the decoding process when a result is acquired; and the decoding result when it is judged that the error correction process has been performed. A first specifying unit that specifies a correction word that is a range in which the error correction process has been performed, among a plurality of code words corresponding to , and an object that represents a range corresponding to the correction word in the code image. a second identification unit for identifying a portion; and a second determination unit for determining whether or not all of the target portions have characteristics indicative of cells.

As mentioned above, in recent years, one of the multiple cells that make up one two-dimensional code has become a special cell that can be read in two ways, a dark color cell and a light color cell, depending on the reading conditions. It has been confirmed that two-dimensional codes are used, for example, for fraudulent purposes. For example, a special cell may be intentionally displayed in an intermediate color between a dark color and a light color, or may be intentionally divided into a dark color portion and a light color portion and displayed.

On the other hand, even in a normal two-dimensional code that does not include such special cells, there are cases where cells with the same display mode as the above special cells are accidentally included due to problems during printing. In addition, when the two-dimensional code is soiled or scraped, some of the cells forming the two-dimensional code may turn into bright cells (or dark cells). However, normally, when a two-dimensional code reading device reads such a normal two-dimensional code, a known error correction process is performed so that a predetermined maximum error correction tolerance rate (for example, 7%, 15 %, 25%, 30%, etc.) and less percentage errors (dirt, damage, chipping, etc.) are corrected. Therefore, normally, even if the two-dimensional code contains up to a predetermined percentage of special cells for some reason, the two-dimensional code reader performs error correction processing and reads the two-dimensional code in advance. can be output as a decoding result.

Here, the "maximum error correction permissible rate" is the maximum value of the permissible rate at which information can be decoded even when the two-dimensional code is damaged. For example, in the case of a two-dimensional code with a maximum error correction tolerance of 25%, even if 25% of the plurality of cell blocks included in the information recording area of the two-dimensional code are damaged, the reading device means that data can be decoded from the two-dimensional code. One "cell block" referred to here is a cell group unit composed of a cell group having eight cells as a unit. In the decoding process, one codeword is extracted from one "cell block". The level of the maximum error correction tolerance rate is set in advance for each two-dimensional code. The two-dimensional code also contains data indicating the maximum error correction tolerance. Therefore, the higher the level of the maximum error correction tolerance rate, the more accurately the data can be decoded even if the two-dimensional code contains a high percentage of cell blocks containing errors.

However, as a result of the analysis by the inventors of the present invention, the above-mentioned special two-dimensional code, which has been confirmed in recent years, can be , In the part other than the cell block containing the special cell, the error correction processing is performed for the number of cell blocks corresponding to the maximum error correction allowable rate (that is, the cell block of the limit value of the maximum error correction allowable rate). It turned out to be accurate and precise. As a result, when the special two-dimensional code is read, the cell block containing the special cell is not treated as an "error", and decoding succeeds while the special cell is read as a dark or light color cell. A devastating situation occurs. As a result, depending on whether the special cell is read as a dark-colored cell or read as a bright-colored cell, two different decoding results may be output. As a result, when the special two-dimensional code is read, there may be inconveniences such as output of reading results not intended by the user of the two-dimensional code reading device (for example, the URL of a harmful site, etc.) as decoding results. There is also

On the other hand, according to the two-dimensional code reading device of the present specification having the above configuration, the control unit, when the decoding result is obtained by decoding based on the code image representing the two-dimensional code, It is determined whether or not error correction processing has been performed in the process of . Then, when it is determined that the error correction processing has been performed, the control unit specifies the correction word that is the range in which the error correction processing has been performed, among the plurality of codewords corresponding to the decoding result. Then, the control section identifies the target portion representing the range corresponding to the correction word in the code image, and determines whether or not the entire target portion has the feature representing the cell. Here, a "codeword" is a character string (combination of alphanumeric characters) representing the decoding result of a cell block (that is, a cell group consisting of eight cells) included in the two-dimensional code.

If the entire target portion has characteristics representing cells, it is possible that the target portion of the two-dimensional code (that is, the range in which error correction processing was performed) did not have stains, damages, chippings, etc. highly sexual. That is, there is a high possibility that the target portion is a portion intentionally provided so that error correction processing is performed. In this case, it can be said that there is a high possibility that the read two-dimensional code is the special two-dimensional code described above.

On the other hand, when it is determined that at least a part of the target portion has characteristics representing an object other than a cell, the target portion of the two-dimensional code (that is, the range in which error correction processing has been performed) includes: There is a high possibility that stains, damages, chips, etc. have occurred. In other words, there is a high possibility that the target portion was not a portion intentionally provided for error correction processing to be performed. In this case, it can be said that there is a high possibility that the read two-dimensional code is not the above special two-dimensional code.

Therefore, according to the two-dimensional code reader, the read two-dimensional code can be read according to the reading conditions by determining whether or not all of the target portions have characteristics representing cells. It is possible to determine whether or not the code is a special two-dimensional code that can output two different decoding results.

The second determination unit obtains an output waveform indicating the brightness of each part in the target portion based on the target portion, and determines whether or not the obtained output waveform exhibits characteristics representing the cell. Thus, it may be determined whether all of the portions of interest have characteristics indicative of the cell.

Each cell (bright cell, dark cell) included in the two-dimensional code is displayed with a predetermined brightness and is a square having sides of a predetermined length. Therefore, the output waveform indicating the brightness of each part of the target portion of the two-dimensional code has a clear boundary between the bright color cells and the dark color cells. Also, the length of the waveform representing the light-colored cells and the length of the waveform representing the dark-colored cells also have lengths within a predetermined range. That is, a predetermined regularity is observed in the output waveform of a two-dimensional code that is free from contamination, damage, chipping, and the like. On the other hand, if the two-dimensional code is soiled, damaged, missing, or the like, the output waveform becomes irregular.

Therefore, according to the above configuration, the two-dimensional code reader determines whether or not the output waveform indicating the brightness of each part in the target part exhibits the characteristics representing the cell, thereby reading the two-dimensional code. is a special two-dimensional code or not.

The second determination unit acquires binarized data obtained by binarizing the brightness of each part in the target part based on the target part, and determines that the acquired binarized data represents the cell. It may be determined whether all of said portions of interest have characteristics indicative of said cell by determining whether or not they do.

Each cell (bright cell, dark cell) included in the two-dimensional code is displayed with a predetermined brightness and is a square having sides of a predetermined length. Therefore, the binarized data obtained by binarizing the brightness of each part of the target portion of the two-dimensional code has a clear boundary between the bright color cells and the dark color cells. Further, the vertical and horizontal lengths of the binarized data representing the light cells and the vertical and horizontal lengths (the number of data) of the binarized data representing the dark cells also have lengths within predetermined ranges. That is, the binarized data of the two-dimensional code, which is free from dirt, damage, chipping, etc., has a predetermined regularity. On the other hand, if the two-dimensional code is defaced, damaged, missing, or the like, the binarized data becomes irregular.

Therefore, according to the above configuration, the two-dimensional code reader reads by determining whether or not the characteristic representing the cell is exhibited based on the binarized data obtained by binarizing the brightness of each part in the target part. Therefore, it is possible to appropriately determine whether or not the obtained two-dimensional code is a special two-dimensional code.

The control unit further (a) does not output the decoding result when it is determined that all of the target portions have characteristics representing the cell, or outputs broadcast information together with the decoding result. and (b) outputting the decoding result when it is determined that at least part of the target portion has a feature representing an object other than the cell. good.

As described above, when all of the target portions have characteristics representing cells, it can be said that the read two-dimensional code is highly likely to be the above-mentioned special two-dimensional code. On the other hand, if it is determined that at least a part of the target portion has features representing an object other than a cell, it is highly probable that the read two-dimensional code is not the special two-dimensional code. I can say Therefore, according to the above configuration, when there is a high possibility that the read two-dimensional code is the above special two-dimensional code, the decoding result is not output, or the notification information is output together with the decoding result. , the user of the two-dimensional code reader can understand that the read two-dimensional code is highly likely to be a special two-dimensional code.

A control method, a computer program, and a computer-readable recording medium storing the computer program for realizing the two-dimensional code reader are also novel and useful.

1 shows an outline of an information code reader; An example of a code image representing a special two-dimensional code is shown. In the code image of FIG. 2, codewords obtained when special cells are read as light-colored cells and codewords obtained when special cells are read as dark-colored cells are shown. 4 shows a flowchart of two-dimensional code reading processing. An example of the output waveform and binarized data of the target portion of the special two-dimensional code is shown. An example of the output waveform and binarized data of the target portion of the damaged two-dimensional code is shown. Another example of a code image representing a special two-dimensional code is shown.

(First embodiment)
(Configuration of two-dimensional code reader 10; FIG. 1)
The two-dimensional code reader 10 of this embodiment shown in FIG. device. In the example of FIG. 1, the two-dimensional code 100 to be read is a QR code (registered trademark of the applicant). The two-dimensional code 100 is configured by arranging a plurality of bright cells and a plurality of dark cells in a two-dimensional matrix. In another example, the two-dimensional code 100 to be read may be a two-dimensional code in another matrix format.

The two-dimensional code reader 10 of this embodiment is, for example, a terminal device such as a smart phone possessed by a user. As shown in FIG. 1 , the two-dimensional code reader 10 includes an operation section 12 , a display section 14 , an imaging section 16 , a control section 20 and a memory 22 .

The operation unit 12 includes one or more keys. A user can operate the operation unit 12 to input various instructions to the two-dimensional code reader 10 . The display unit 14 is a display for displaying various information including the decoding result of the read two-dimensional code 100 . Also, the operation unit 12 and the display unit 14 may be a touch panel in which both are integrally configured. The image capturing unit 16 is a CCD camera capable of capturing an image within a predetermined imageable range. A code image C (see FIG. 1, FIG. 2, etc.) representing the two-dimensional code 100 is obtained by imaging the two-dimensional code 100 with the imaging unit 16 .

The control unit 20 executes various processes including a code reading process (see FIG. 4), which will be described later, according to programs stored in the memory 22 . In this embodiment, the data recorded in the two-dimensional code 100 can be acquired and output by the control unit 20 executing the code reading process. The memory 22 is composed of ROM (abbreviation for Read Only Memory), RAM (abbreviation for Random Access Memory), and the like. As described above, the memory 22 stores various programs such as the OS program and the reading application program for executing the code reading process described above. Furthermore, the memory 22 also has a temporary storage area for storing various data generated in the process of executing code reading processing, which will be described later.

(Structure and mechanism of special two-dimensional code; Figures 2 and 3)
As described above, the two-dimensional code reader 10 reads the two-dimensional code 100 . On the other hand, in recent years, a two-dimensional code (hereafter referred to as (referred to as a "special two-dimensional code") has been confirmed to be used for fraudulent purposes, for example. The "special cells" referred to here are intentionally displayed in intermediate colors between dark and bright colors, or are intentionally displayed by dividing them into dark and bright color portions. When such a special two-dimensional code is read by a conventional two-dimensional code reader, a special cell can be read as a bright cell or as a dark cell. Then, depending on whether the special cell is read as a bright color cell or a dark color cell, two different decoding results may be output. As a result, when the special two-dimensional code is read, there may be inconveniences such as output of reading results not intended by the user of the two-dimensional code reading device (for example, the URL of a harmful site, etc.) as decoding results. There is also

The configuration of such a special two-dimensional code and the mechanism by which two different decoding results are output when the special two-dimensional code is read will be described below with reference to FIGS. A case in which the two-dimensional code reader 10 of this embodiment reads a two-dimensional code 100, which is a special two-dimensional code, will be described below as an example. FIG. 2(a) is an example of a two-dimensional code 100 (and a code image C representing the two-dimensional code 100) imaged by the imaging unit 16 of the two-dimensional code reader 10. FIG. That is, the two-dimensional code 100 in (a) of FIG. 2 is a special two-dimensional code. The two-dimensional code 100 consists of dark (specifically black) cells (hereinafter referred to as “dark cells”) and light (specifically white) cells (hereinafter referred to as “light cells”). made up of combinations. The two-dimensional code 100 includes finder patterns 40 arranged at three corners, one alignment pattern 42 , and a data cell area 44 arranged in the center of the finder pattern 40 and the alignment pattern 42 .

The finder pattern 40 is a portion that is recognized first when reading the two-dimensional code 100 and is a pattern for specifying the top, bottom, left, and right positions of the two-dimensional code 100 . The position, size, shape, etc. of the finder pattern 40 are determined in advance. By recognizing the finder pattern 40, the two-dimensional code reader 10 can read the data recorded in the two-dimensional code 100 from any direction regardless of the orientation of the two-dimensional code 100. The alignment pattern 42 is a portion for correcting positional deviation of each cell caused by distortion.

The data cell area 44 is an area containing various cells for expressing data recorded in the two-dimensional code 100 . The data cell area 44 contains data characters, error correction codes, and the like.

Here, the “data character” includes data recorded in the two-dimensional code 100 . The data represented by the data characters includes not only the data itself to be decoded, but also data indicating the maximum error correction allowable rate. The maximum error correction allowable rate indicates the maximum allowable rate (for example, 7%, 15%, 25%, 30%, etc.) at which data can be decoded even when the two-dimensional code 100 is damaged. . For example, in the case of an information code with a maximum error correction tolerance of 20%, 44 cell blocks CB (see FIG. and the portion excluding the alignment pattern 42) are damaged, the two-dimensional code reader 10 can decode data from the two-dimensional code 100. means that The "error correction code" is information that enables the two-dimensional code reader 10 that has read the two-dimensional code 100 to detect and correct errors in the read data. The two-dimensional code reader 10 compares the read data with the error correction code to determine whether or not there is an error in the data (i.e., missing), and if there is an error, the error The erroneous portion can be complemented based on the correction code. This function is called an error correction function and is generally known. Further, the process of complementing the error part based on this error correction function may be referred to as "error correction process" below.

Furthermore, in this embodiment, the data cell area 44 includes one special cell 50 intentionally displayed in an intermediate color between light and dark. That is, the two-dimensional code 100, which is a special two-dimensional code, includes one special cell 50. FIG. When the special cell 50 is read by the two-dimensional code reader 10, the special cell 50 can be read in a bright light depending on the reading conditions (for example, the amount of light when the special two-dimensional code is captured). Sometimes it is read as a color cell and sometimes it is read as a dark color cell. Then, depending on whether the special cell 50 is read as a bright color cell or a dark color cell, two different decoding results may be output. In this example, when the special cell 50 is read as a dark cell (pattern A), the decoding result "http://srv.prof.net/~lob" is output. On the other hand, when the special cell 50 is read as a bright cell (pattern B), the decoding result "http://srv.prof.net/~lab" is output. Both the decoding result of pattern A and the decoding result of pattern B indicate the URL of the website, but part of the URL is different between "a" and "o". Thus, when the two-dimensional code 100, which is a special two-dimensional code, is read, two different decoding results are output. As a result, when the special two-dimensional code is read, a decoding result not intended by the user (for example, the URL of a harmful site, etc.) may be output.

As shown in FIG. 2(b), a large number of cells included in the data cell area 44 constitute a plurality of cell blocks CB, which are cell groups of eight cells each. In the example of FIG. 2(b), the two-dimensional code 100 has a total of 44 cell blocks CB (D1 to D28 and E1 to E16 in FIG. 2(b)). Of these, 28 cell blocks D1 to D28 are cell blocks corresponding to the data characters described above. Each of the cell blocks D1-D28 represents a two-digit codeword (eg, "41" in FIG. 3(a)) expressed in hexadecimal notation. The 16 cell blocks E1 to E16 are cell blocks corresponding to the error correction codes described above. Each of the cell blocks E1 to E16 also represents a two-digit codeword represented in hexadecimal notation (for example, "E6" in (a) of FIG. 3).

Before describing the mechanism for outputting two types of decoding results based on the special two-dimensional code (see (a) and (b) of FIG. 3), in a normal two-dimensional code that does not include the special cell 50, some A mechanism for correctly outputting the expected (that is, one set of) decoded results even when a special case occurs in the cells of . In a normal two-dimensional code, a cell having a display mode similar to that of the special cell 50 may be accidentally included due to a problem during printing or the like. Further, when the two-dimensional code is soiled or scraped, some of the cells forming the two-dimensional code may turn into dark cells (or bright cells). However, normally, when the two-dimensional code reading device 10 reads such a two-dimensional code, the error correction processing described above is performed so that a predetermined maximum error correction allowable rate (for example, 7%, 15% , 25%, 30%, etc.) are corrected. Therefore, normally, even if the two-dimensional code contains up to a predetermined percentage of special cells for some reason, the two-dimensional code reader 10 performs error correction processing and then preliminarily reads the two-dimensional code. Data recorded in the code (a series of data) can be output as the decoding result. That is, when a normal two-dimensional code having a specific cell configuration is read by the two-dimensional code reader 10, each time the decoded result output as the read result is the one recorded in advance in the normal two-dimensional code. It is intended to be data of the type

On the other hand, the above special two-dimensional code, which has been confirmed in recent years, is when the special cell 50 included in the data cell area 44 is read as a dark cell (see FIG. 3(a) [Pattern A]), In both the case of reading as a color cell (see (b) [Pattern B] in FIG. 3) and the case of reading the It has been found that the error correction processing is intentionally and precisely set so that the cell block (that is, the cell block at the limit of the maximum error correction allowable rate) is subjected to error correction processing. As a result, when the special two-dimensional code is read, the cell block containing the special cell 50 is not treated as an "error", and the special cell 50 is read as a dark cell or a light color cell. do. As a result, depending on whether the special cell 50 is read as a dark-colored cell or a bright-colored cell, two different decoding results are output (see FIGS. 3A and 3B). ).

This will be explained in more detail with reference to FIGS. 3(a) and 3(b). FIG. 3(a) shows a specific example (pattern A) in which the special cell 50 of the two-dimensional code 100 (see FIG. 2), which is a special two-dimensional code, is read as a dark cell. In pattern A, 44 codewords after correction corresponding to each cell block are obtained by performing error correction processing in the decoding process. FIG. 3(b) shows a specific example of a case (pattern B) in which the special cell 50 is read as a bright color cell in a similar situation. In pattern B, error correction processing is performed, resulting in 44 corrected codewords corresponding to each cell block (that is, 44 corrected codewords that are partially different from those in pattern A). is obtained. For both patterns, the maximum error correction tolerance rate set for the two-dimensional code 100, which is a special two-dimensional code, is 20%. That is, during decoding, errors in up to 9 cell blocks out of 44 cell blocks CB can be corrected.

(Pattern A; (a) in FIG. 3)
When the special cell 50 of the two-dimensional code 100 (see FIG. 2), which is a special two-dimensional code, is read as a dark cell, 44 cells as shown in the upper part of FIG. codeword is obtained. Of the 44 codewords, the first 28 codewords (from "41" to "F7") are codewords corresponding to cell blocks D1 to D28 (ie, cell blocks corresponding to data characters). Of these, "96" indicated by hatching and "C6" next to it are codewords corresponding to the English letter "o". Of the 44 codewords, the latter 16 codewords (from "E6" to "C6") are codewords corresponding to cell blocks E1 to E16 (that is, cell blocks corresponding to error correction codes). is. Among them, "71" indicated by diagonal hatching is a code word obtained by reading the special cell 50 as a dark cell.

As described above, the maximum error correction tolerance rate set for the two-dimensional code 100 is 20%. The two-dimensional code 100, which is a special two-dimensional code, is a cell block code corresponding to the maximum error correction tolerance rate in both cases when the special cell 50 is read as a dark cell and when it is read as a light color cell. It is intentionally and precisely set so that error correction processing is performed on the word. Therefore, the two-dimensional code reader 10 corrects errors in the codewords corresponding to 9 cell blocks among the codewords corresponding to 44 cell blocks CB. In the example of FIG. 3a, the 9 underlined codewords are corrected. In pattern A, the nine codewords to be subjected to error correction processing are all codewords corresponding to cell blocks E1 to E16.

As a result of the error correction processing, 44 codewords as shown in the lower part of FIG. 3(a) are acquired. Of the 44 codewords in the figure, codewords that have undergone correction processing (hereinafter sometimes referred to as "correction words") are underlined. Even after the error correction processing, the shaded “96” and its adjacent “C6” are maintained unchanged from before the error correction processing. That is, "96" and "C6" represent the alphabetic character "o" as before the error correction processing. As a result, the two-dimensional code reader 10 obtains the decoding result "http: //srv.prof.net/~lob" can be output.

(Pattern B; (b) in FIG. 3)
When the special cell 50 of the two-dimensional code 100 (see FIG. 2), which is a special two-dimensional code, is read as a bright color cell, 44 as shown in the upper part of FIG. codewords are obtained. Again, the first 28 codewords ("41" to "F7") are codewords corresponding to cell blocks D1 to D28 (ie, cell blocks corresponding to data characters). Of these, "96" indicated by hatching and "C6" next to it are codewords corresponding to the English letter "o". Of the 44 codewords, the latter 16 codewords (from "E6" to "C6") are codewords corresponding to cell blocks E1 to E16 (that is, cell blocks corresponding to error correction codes). is. Of these, "F1" indicated by diagonal hatching is a code word obtained by reading the special cell 50 as a bright cell. Thus, it differs from the codeword ("71") that would be obtained if the special cell 50 were read as a light cell.

In this case as well, errors in the number (nine) of codewords corresponding to the maximum error correction tolerance (20%) set in the two-dimensional code 100 are corrected. Specifically, the nine underlined codewords in (b) of FIG. 3 are corrected. The codewords to be subjected to error correction processing in pattern B are different from those in pattern A. FIG. As shown in FIG. 3B, in pattern B, error correction processing is performed on codewords (corresponding to error correction codes) corresponding to cell blocks E1 to E16, and cell blocks D1 to D28 are subjected to error correction processing. Of the corresponding codeword (corresponding to the data character), error correction processing is also performed on "C6", which is the part that constitutes the English character "o".

As a result of the error correction processing, 44 codewords as shown in the lower part of FIG. 3(b) are obtained. The correction words of the 44 codewords in the figure are underlined. In pattern B, "C6" next to "96" indicated by shading is corrected to "16". "96" and "16" represent the English letter "a". As a result, the two-dimensional code reader 10 obtains the decoding result "http: //srv.prof.net/~lab" can be output. In this way, the decoding result of pattern A and the decoding result of pattern B both indicate the URL of the website, but part of the URL is different between "a" and "o".

When the two-dimensional code 100, which is a special two-dimensional code, is read (that is, decoded), the two-dimensional code reading device 10 performs the processing described above to output two decoding results.

(Code reading process; Fig. 4)
In this embodiment, the control unit 20 of the two-dimensional code reader 10 executes the code reading process of FIG. 4 to determine whether the read two-dimensional code 100 is a special two-dimensional code as described above. can be determined. Code reading processing executed by the control unit 20 of the two-dimensional code reader 10 of the present embodiment will be described below with reference to FIG. A user can input a predetermined reading instruction to the operation unit 12 of the two-dimensional code reading device 10 in which the reading application program for reading the two-dimensional code is activated. When the reading instruction is input, the control section 20 starts the code reading process of FIG.

At S10, the control unit 20 monitors that the code image C representing the two-dimensional code 100 is captured. When the code reading process is started, the control unit 20 activates the imaging unit 16 to start capturing an image within the imaging range. At this time, the user changes the position and angle of the two-dimensional code reader 10 so that the two-dimensional code 100 is included in the imaging range of the imaging unit 16, thereby causing the imaging unit 16 to image the two-dimensional code 100. be able to. As a result, an image representing the two-dimensional code 100 is captured by the imaging unit 16 . Then, the control unit 20 determines whether or not a feature representing the two-dimensional code 100 (for example, the finder pattern 40, etc.) exists in the captured image, and determines that the feature representing the two-dimensional code 100 exists. If so, it is determined that the code image C has been captured (that is, YES is determined in S10), and the process proceeds to S12.

At S12, the control unit 20 attempts decoding based on the code image C imaged at S10. That is, the control unit 20 decodes the data recorded in the two-dimensional code 100 represented by the code image C according to a known decoding technique. At that time, as described above, the control unit 20 also performs error correction processing as necessary (see FIGS. 2 and 3).

At S14, the control unit 20 determines whether or not the decoding is successful. As a result of the attempted decoding in S12, if the decoding result has been obtained, the control unit 20 determines YES in S14, and proceeds to S16. On the other hand, if acquisition of the decoding result fails for some reason (for example, when the damage level of the two-dimensional code 100 represented by the code image C exceeds the maximum error correction tolerance), the control unit 20 The determination is NO, and the code reading process ends with an error.

In S16, the control unit 20 determines whether error correction processing has been performed in the process of decoding. Specifically, in S16, first, the control unit 20 refers to the codeword (see FIG. 3) stored in the primary storage area of the memory 22 in the decoding process, thereby performing error correction processing in the decoding process. is performed. As a result, when it is determined that error correction processing has been performed in the process of decoding, the control unit 20 determines YES in S16 and proceeds to S18. On the other hand, if it is determined that error correction processing has not been performed in the process of decoding, the control unit 20 determines NO in S16 and proceeds to S30.

In S18, the control unit 20 causes the primary storage area of the memory 22 to store the code image C imaged in S10.

Next, in S20, the control unit 20 refers to the codewords (see FIG. 3) stored in the primary storage area of the memory 22 in the process of decoding, and specifies the correction word, which is the codeword for which error correction processing has been performed. do.

Next, in S22, the control unit 20 refers to the code image C stored in the memory 22, and identifies the target portion of the code image C corresponding to the correction word identified in S20. Specifically, in S22, first, the control unit 20 identifies a cell block in the code image C that corresponds to the correction word. Then, the control section 20 specifies the range corresponding to the specified cell block in the code image C as the target portion.

Next, in S24, the control unit 20 analyzes the target portion specified in S22. In this embodiment, in S24, first, the control unit 20 acquires an output waveform indicating the brightness of each portion of the target portion. Then, the control unit 20 analyzes the obtained output waveform and identifies the pattern formed by the bright color portion and the dark color portion of the target portion.

In subsequent S26, the control unit 20 determines whether or not the entire target portion is a cell as a result of the analysis performed in S24. That is, the control unit 20 determines whether or not the output waveform indicating the lightness of each part of the target portion obtained in S24 has characteristics representing cells in the entire target portion. As a result, when it is determined that the output waveform of the target portion has characteristics representing cells for the entire target portion (see FIG. 5 described later), the control section 20 determines YES in S26, and determines YES in S28. proceed to Conversely, when it is determined that at least part of the target portion of the output waveform of the target portion has features representing objects other than cells (for example, stains, defects, etc.) (see FIG. 6 described later). , the control unit 20 determines NO in S26, and proceeds to S30.

With reference to FIGS. 5 and 6, specific examples of cases where YES is determined in S26 and NO is determined in S26 will be described. FIG. 5 shows an example of the case where the target portion TP of the code image C has cell-specific features (when determined as YES in S26). In the example of FIG. 5, the part surrounded by the thick line in the code image C is the target part TP corresponding to the correction word. As shown in FIG. 5, in this example, the target portion TP is free of conspicuous dirt and the like, and the target portion TP is entirely composed of cells. Each cell (bright cell, dark cell) included in the two-dimensional code 100 is displayed with a predetermined brightness and is a square having sides of a predetermined length. Therefore, in the example of FIG. 5, the output waveform of the target portion TP has a clear boundary between the bright portion and the dark portion. Also, the length of the waveform representing the bright color portion (horizontal width in the figure) and the length of the waveform representing the dark color portion also have lengths corresponding to the predetermined cell size. When all the output waveforms of each portion of the target portion TP have such characteristics, it can be said that the entire target portion TP is a cell. In that case, the control unit 20 determines YES in S26 and proceeds to S28.

On the other hand, FIG. 6 shows the case where at least a part of the target portion TP of the code image C has a feature representing an object other than the cell (for example, dirt, chipping, etc.) (when it is determined NO in S26). ) is an example. In the example of FIG. 6 as well, the part surrounded by the thick line in the code image C is the target part TP corresponding to the correction word. As shown in FIG. 6, in this example, a large dirt 60 is attached to the target portion TP. Therefore, in the example of FIG. 6, the output waveform of the target portion TP includes a portion having an irregular boundary between the bright portion and the dark portion that is clearly different from the cell. Moreover, in at least a part, the length of the waveform representing the bright color portion (horizontal width in the drawing) and the length of the waveform representing the dark color portion also have lengths different from the predetermined cell size. When at least part of the output waveform of each portion of the target portion TP has such characteristics, all of the target portion TP is not a cell (that is, at least a portion of the target portion TP is an object other than a cell (for example, dirt or dust). It can be said that it has a feature representing chipping etc.). In that case, the control unit 20 determines NO in S26 and proceeds to S30.

In S28, the control unit 20 outputs (for example, displays on the display unit 14) notification information related to the fact that the read two-dimensional code 100 is a special two-dimensional code together with the obtained decoding result. The notification information includes, for example, a message for notifying the user that the two-dimensional code 100 that has been read is highly likely to have undergone special processing and that the user should pay attention to the decoding result. If it is determined YES in S26, the target portion of the code image C corresponding to the correction word that was the target of the error correction processing is , all have the characteristics of cells and are not contaminated (see FIG. 5). That is, there is a high possibility that the target portion TP is a portion intentionally provided so that error correction processing is performed. In this case, it can be said that there is a high possibility that the read two-dimensional code 100 is the special two-dimensional code described above. In S28, the control unit 20 outputs notification information in addition to the obtained decoding result, thereby notifying the user that the read two-dimensional code 100 is likely to be a special two-dimensional code. In addition to notification, it is possible to call attention to confirm whether or not the decoding result is information as planned.

On the other hand, in S30, the control unit 20 outputs the acquired decoding result. For example, if it is determined as NO in the above S26, it means that there is a high possibility that the error correction process was performed in the decoding process because the two-dimensional code 100 was damaged (see FIG. 6). . In other words, in this case, it can be said that the read two-dimensional code 100 is highly likely to be a normal two-dimensional code rather than a code intentionally configured for error correction processing. In this case, in S30, the control unit 20 can output the obtained decoding result as usual.

The configuration and operation of the two-dimensional code reader 10 of this embodiment have been described above. As described above, when the decoding result is obtained by performing decoding based on the code image C representing the two-dimensional code 100 (YES in S14 of FIG. 4), the control unit 20 performs error correction processing during the decoding process. is performed (S16). Then, when it is determined that the error correction processing has been performed (YES in S16), the control unit 20 selects the correction word, which is the range in which the error correction processing has been performed, from among the plurality of codewords corresponding to the decoding result. Identify (S20). Then, the control section 20 identifies the target portion representing the range corresponding to the correction word in the code image C, and determines whether or not the entire target portion has the characteristic representing the cell (S26). . If all of the target portion have features representing cells (YES in S26), the target portion of the two-dimensional code 100 (that is, the range in which the error correction processing has been performed) has stains, damages, defects, and the like. Most likely it did not occur. That is, there is a high possibility that the target portion is a portion intentionally provided so that error correction processing is performed. In this case, it can be said that there is a high possibility that the read two-dimensional code is the special two-dimensional code described above. On the other hand, if it is determined that at least a part of the target portion has features representing an object other than a cell (NO in S26), the target portion of the two-dimensional code has stains, damages, defects, and the like. likely to have occurred. In other words, there is a high possibility that the target portion was not a portion intentionally provided for error correction processing to be performed. In this case, it can be said that there is a high possibility that the read two-dimensional code is not the above special two-dimensional code. Therefore, according to the two-dimensional code reader 10 of the present embodiment, the read two-dimensional code 100 is read by determining whether or not all of the target portions have characteristics representing cells. It is possible to appropriately determine whether or not the code is a special two-dimensional code that can output two different decoding results according to the conditions.

Further, as described above, in the present embodiment, the control unit 20 obtains an output waveform indicating the brightness of each part within the target portion, and determines whether or not the obtained output waveform indicates characteristics representing a cell. Then, it is determined whether or not all of the target portions have characteristics representing cells (S26). As described above, the output waveform of the two-dimensional code 100 that is not defaced, damaged, chipped, etc. has a predetermined regularity. On the other hand, if the two-dimensional code 100 is soiled, damaged, missing, or the like, the output waveform becomes irregular. Therefore, according to this embodiment, the two-dimensional code reader 10 determines whether or not the read two-dimensional code has characteristics representing a cell based on the output waveform indicating the brightness of each part in the target portion. Whether or not the code 100 is a special two-dimensional code can be appropriately determined.

The correspondence relationship between this embodiment and the claims will be explained. The processing of S12, the processing of S16, the processing of S20, the processing of S22, and the processing of S26 in FIG. This is an example of processing executed by the "specifying unit" and the "second determining unit". The processing of S28 and S30 is an example of the processing executed by the "output control unit".

(Second embodiment)
The two-dimensional code reader 10 of the second embodiment will be described with a focus on the differences from the first embodiment. The basic configuration and operation of the two-dimensional code reader 10 of this embodiment are also common to those of the first embodiment. However, in this embodiment, the method of analyzing the target portion in S24 of the code reading process in FIG. 4 is different from that in the first embodiment.

In this embodiment, in S24, first, the control unit 20 acquires binarized data obtained by binarizing the brightness of each portion of the target portion. Then, the control unit 20 analyzes the acquired binary data and specifies the pattern formed by the bright color portion and the dark color portion of the target portion. In subsequent S26, the control unit 20 determines whether or not the entire target portion is a cell as a result of the analysis performed in S24. That is, the control unit 20 determines whether or not the binarized data obtained by binarizing the brightness of each part of the target portion obtained in S24 has characteristics representing cells in the entire target portion. . As a result, when it is determined that the binarized data has characteristics representing cells for all of the target portion (see FIG. 5 described later), the control section 20 determines YES in S26, and proceeds to S28. move on. Conversely, if it is determined that the binarized data has features representing objects other than cells (for example, stains, defects, etc.) for at least part of the target portion (see FIG. 6 described later), The control unit 20 determines NO in S26 and proceeds to S30.

In the present embodiment as well, with reference to FIGS. 5 and 6, specific examples of cases in which YES is determined in S26 and NO is determined in S26 will be described. FIG. 5 shows an example of the case where the target portion TP of the code image C has cell-specific features (when determined as YES in S26). The binarized data is data in which bright color portions are represented by "0" and dark color portions are represented by "1" after scanning the inside of the target portion. As described above, in the example of FIG. 5, the target portion TP has no conspicuous stains and the like, and the target portion TP is entirely composed of cells. Each cell (bright cell, dark cell) included in the two-dimensional code 100 is displayed with a predetermined brightness and is a square having sides of a predetermined length. Therefore, in the example of FIG. 5, the binarized data of the target portion TP has a clear boundary between the area of "0" representing the bright color portion and the area of "1" representing the dark color portion. In addition, the vertical and horizontal lengths (number of data) of the "0" area representing the light color part and the vertical and horizontal length (number of data) of the "1" area representing the dark color part are also set to the predetermined cell size. It has a corresponding length (number of data). When all the binarized data of the target portion TP have such characteristics, it can be said that the entire target portion TP is a cell. In that case, the control unit 20 determines YES in S26 and proceeds to S28.

On the other hand, FIG. 6 shows the case where at least a part of the target portion TP of the code image C has a feature representing an object other than the cell (for example, dirt, chipping, etc.) (when it is determined NO in S26). ) is an example. As described above, in the example of FIG. 6, a large dirt 60 is attached to the target portion TP. Therefore, in the example of FIG. 6, the binarized data of the target portion TP has an area of "0" representing the bright color portion and an area of "1" representing the dark color portion, which clearly differs from the cell. Contains parts with regular boundaries. Moreover, in at least a part, the vertical and horizontal lengths (the number of data) of the “0” region representing the light color portion and the vertical and horizontal lengths (the number of data) of the “1” region representing the dark color portion are also , has a length (the number of data) different from the predetermined cell size. When at least part of the binarized data of the target portion TP has such characteristics, the entire target portion TP is not a cell (that is, at least a portion of the target portion TP is an object other than a cell (for example, dirt or dust). It can be said that it has a feature representing chipping etc.). In that case, the control unit 20 determines NO in S26 and proceeds to S30.

As described above, the binarized data of the two-dimensional code 100, which is free from dirt, damage, chipping, etc., has a predetermined regularity. On the other hand, if the two-dimensional code 100 is defaced, damaged, missing, or the like, the binarized data becomes irregular. Therefore, in this embodiment as well, the two-dimensional code reader 10 reads by judging whether or not the characteristic representing the cell is exhibited based on the binarized data obtained by binarizing the brightness of each part in the target part. Therefore, it is possible to properly determine whether the obtained two-dimensional code 100 is a special two-dimensional code.

(Third embodiment)
This embodiment is a modification of the first and second embodiments described above. In the first and second embodiments described above, the special two-dimensional code to be determined (for example, the two-dimensional code 100 in FIG. 2) includes one special cell 50 displayed in an intermediate color between light and dark. In this embodiment, the special two-dimensional code to be determined includes a special cell 150 that is displayed by intentionally dividing the cell into bright and dark portions, as shown in the two-dimensional code 200 of FIG. In this case as well, the special cell 150 may be read as a dark cell or as a bright cell depending on various reading conditions (for example, the amount of light when the special two-dimensional code is captured). may be The two-dimensional code reader 10 disclosed in the above-described first and second embodiments can read the special two-dimensional code (that is, two-dimensional code 200) of the type shown in FIG. An operation similar to the example can be performed.

Although each embodiment of the present invention has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, the following modifications may be adopted.

(Modification 1) In each of the above-described embodiments, when the control section 20 determines YES in S26 of FIG. Without being limited to this, the control unit 20 may output only the notification information without outputting the decoding result when determining YES in S26 of FIG. In still another example, neither the decoding result nor the broadcast information may be output.

(Modification 2) The method of analyzing the target portion (S24) in the code reading process of FIG. The method is not limited to the method described in each embodiment, and any other method may be adopted. Therefore, for example, the control unit 20 extracts the feature points included in the image of the target portion of the code image C, and determines whether or not all the extracted feature points indicate the features of the cells, thereby determining the target portion. A determination may be made as to whether all have characteristics indicative of a cell.

(Modification 3) In each of the above-described embodiments, the special two-dimensional code is described as a code that can output two types of decoding results depending on the reading conditions. The special two-dimensional code is not limited to this, and may be a code that can output three or more decoding results depending on reading conditions. Also, the special two-dimensional code may contain two or more special cells in order to enable the output of such multiple decoding results.

The technical elements described in this specification or in the drawings exhibit technical utility either singly or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings achieve multiple purposes at the same time, and achieving one of them has technical utility in itself.

10: Two-dimensional code reader 12: Operation unit 14: Display unit 16: Imaging unit 20: Control unit 22: Memories 100, 200: Two-dimensional code 40: Finder pattern 42: Alignment pattern 44: Data cell areas 50, 150: Special cell 60: Dirt C: Code image CB: Cell blocks D1 to D26: Cell blocks E1 to E16 corresponding to data characters: Cell blocks corresponding to error correction code TP: Target part

Claims (4)

an imaging unit for imaging a two-dimensional code configured by arranging a plurality of light-colored cells and a plurality of dark-colored cells in a two-dimensional matrix;
a control unit and
The control unit
a decoding unit that decodes information recorded in the two-dimensional code based on the code image representing the two-dimensional code captured by the imaging unit;
a first determination unit that determines whether or not an error correction process has been performed in the decoding process when a decoding result is obtained by performing the decoding;
a first identifying unit that identifies a correction word, which is a range in which the error correction processing has been performed, among a plurality of codewords corresponding to the decoding result when it is determined that the error correction processing has been performed; ,
a second specifying unit that specifies a target portion representing a range corresponding to the correction word in the code image;
a second determination unit that determines whether all of the target portions have characteristics indicative of cells;
Two-dimensional code reader. The second determination unit obtains an output waveform indicating the brightness of each part in the target portion based on the target portion, and determines whether or not the obtained output waveform exhibits characteristics representing the cell. 2. The two-dimensional code reader according to claim 1, which determines whether or not all of said target portions have characteristics indicative of said cells. The second determination unit acquires binarized data obtained by binarizing the brightness of each part in the target part based on the target part, and determines that the acquired binarized data represents the cell. 2. The two-dimensional code reader according to claim 1, wherein it is determined whether or not all of said target portions have characteristics representing said cells by determining whether or not said cells are represented. The control unit further
(a) not outputting the decoding result or outputting broadcast information together with the decoding result when it is determined that all of the target portions have characteristics representing the cell; 4. The method according to any one of claims 1 to 3, further comprising an output control unit for outputting the decoding result when it is determined that at least part of the target portion has a feature representing an object other than the cell. The two-dimensional code reader according to item 1.

Images