JP3726395B2 - Two-dimensional code and two-dimensional code reading method - Google Patents

Description

【００５９】
また他方の頂点セル中心位置ｉ（Ｘｉ，Ｙｉ）についても同様な関係から次の連立方程式を解くことにより得られる。
【００６０】
【数２】

【００６１】
こうして求められた２つ頂点セルの中心位置ｈ，ｉの周辺画像をそれぞれ精査して、枠状正方形５５ａの頂点のエッジの形状等から、正確な頂点セルの中心座標を求めて、その座標を正式に中心位置ｈ，ｉの座標とする。
そして、隣接する頂点セルの中心位置ｈ，ｆ，ｉ，ｇの間を６等分することにより、黒の枠状正方形５５ａを構成するセルの中心位置と、１セルのサイズとを決定する。
【００６２】
こうして、位置決め用シンボル５４の形状と中心位置Ｓｃとが決定する。
次に位置決め用シンボル５４に基づいてサイズコード６０，６２の検出処理を行う（Ｓ１２３）。
まず、図１１に示すごとく、対角にある頂点セルの中心位置ｆ，ｇを結ぶ直線を、この直線の長さの１／３分、各頂点側へそれぞれ延長した端点Ｆ，Ｇを求める。同様に、対角にある頂点セルの中心位置ｈ，ｉを結ぶ直線を、この直線の長さの１／３分、各頂点側へそれぞれ延長した端点Ｈ，Ｉを求める。
【００６３】
この端点Ｆ，Ｇ，Ｈ，Ｉの内、隣接する端点Ｈ，Ｆの間を直線状に辿ってセル内容を読み込む。すなわち、位置決め用シンボル５４の辺５４ｄから１．５セル分離れた位置で、辺５４ｄに沿ってセルの内容を読み取る処理が行われる。同様に、隣接する端点Ｆ，Ｉの間を辺５４ａに沿って、隣接する端点Ｉ，Ｇの間を辺５４ｂに沿って、および隣接する端点Ｇ，Ｈの間を辺５４ｃに沿って、それぞれセルの内容を読み取る処理が行われる。
【００６４】
図２に示したごとく、位置決め用シンボル５４の隣接する２つの辺５４ａ，５４ｂに沿って、１セル離れてサイズコード６０，６２が配列している。すなわち、２つの辺５４ａ，５４ｂから１．５セル分離れた位置は、サイズコード６０，６２のセルの中心位置を通ることになる。
【００６５】
したがって、端点Ｆ，Ｇ，Ｈ，Ｉ間の４つの読取処理により、図６に示したサイズコードのいずれかが、２つの読取処理にてそれぞれ検出される。
次に、同一サイズコードが２つ検出されたか否かが判定され（Ｓ１２４）、もし、１つのみ検出されたり、３つ以上検出されたり、全く検出されなかったり、あるいはサイズコードが検出されても両者の内容が異なっていたりした場合には（Ｓ１２４で「ＮＯ」）、エラーとしてステップＳ１８０に移る。
【００６６】
同一サイズコードが２つのみ検出されれば（Ｓ１２４で「ＹＥＳ」）、次に２次元コード５２の形状の決定がなされる（Ｓ１２５）。
すなわち、ステップＳ１２３で読み取られたサイズコード６０，６２の位置および内容に基づいて、位置決め用シンボル５４に対していずれの辺側にデータセルが存在するか、更に、どれだけのサイズまで広がっているかを決定する。
【００６７】
つまり、位置決め用シンボル５４の辺５４ａ〜５４ｄの内、サイズコード６０，６２が検出された側の辺方向に、データセルが存在すると決定する。そして、得られたサイズコード６０，６２の種類から、比率を決定し、２次元コード５２が位置決め用シンボル５４のサイズの何倍かを決定する。ここでは、比率が１５／７のサイズコード６０，６２が得られたので、２次元コード５２は、図２に示したサイズ１５セル×１５セルであると決定する。
【００６８】
次に、各データセルの位置決定と、データセルの白黒の種類を決定する（Ｓ１４０）。すなわち、ステップＳ１２１にて決定されている位置決め用シンボル５４の１セルのサイズ、および位置決め用シンボル５４の位置から、辺５４ａ，５４ｂ側へ、それぞれ、位置決め用シンボル５４のサイズも含めて１５セル分の範囲にあるデータセルの各中心位置を計算して求めて、その中心位置から各データセルの黒か白かの種類を読み取ってデコードし、２次元コード５２が表している情報を得る。
【００６９】
次にこのコード内容が正常なものか否かが判定される（Ｓ１６０）。例えば、白と黒とのセル数が予め決められている特定の数になっているか否か、あるいは表されているデータを所定の計算方法で計算した結果が、２次元コード５２の所定位置に表示されているデータと一致するか否かを検査すること等により、正常にコードが読み取られているか否かが判定される。
【００７０】
正常なコードでなければ（Ｓ１６０で「ＮＯ」）、次の画像の検出をＣＣＤ４に指示して（Ｓ１８０）、処理を終了する。
正常なコードであれば（Ｓ１６０で「ＹＥＳ」）、そのコード内容をホストコンピュータ等の他の装置へ出力したり、そのコード内容を特定のメモリに記憶したり、そのコード内容に対応した処理を実行したり、あるいはそのコード内容に対応した指示を出力したりする処理が行われる（Ｓ１７０）。
【００７１】
そして、次の新たな２次元コードの読み取りのために、画像の検出をＣＣＤ４に指示して（Ｓ１８０）、処理を終了する。
なお、他のサイズコード７０，７２でサイズが表されている１１セル×１１セルの２次元コード７４（図７）、およびサイズコード８０，８２でサイズが表されている２１セル×２１セルの２次元コード８４（図８）についても、同一の処理で、無駄な読み取りをしたり読みこぼしをしたりすることなく、データ領域７８，８８の内容を正確に読み取ることができる。なお、各位置決め用シンボル７６，８６は、図２の２次元コード５２の位置決め用シンボル５４と同一である。
【００７２】
本実施の形態は、上述したごとく、位置決め用シンボル５４の２つの辺５４ａ，５４ｂ側に隣接する位置に、サイズコード６０，６２，７０，７２，８０，８２を配置し、位置決め用シンボル５４が検出されれば、位置決め用シンボル５４の形状と位置とに基づいて直ちに、サイズコード６０〜８２を検出して、そのサイズコード６０〜８２の位置と内容とによりデータセルの存在する方向とその範囲を決定している。
【００７３】
このため、位置決め用シンボル５４は１つでも、データセルが位置決め用シンボル５４に対してどのような位置にどのような範囲で存在するのかが直ちに判明し、２次元コード５２の情報を、無駄な読み取りをしたり読みこぼしをしたりすることなく正確に読み取ることができる。
【００７４】
したがって、小さなサイズの２次元コード５２が必要とされる用途でも、２次元コード５２に３つの位置決め用シンボル５４を用いなくても良いので、３つの位置決め用シンボル５４を存在させるために生じる２次元コード５２の小型化の限界を、十分に小さいものとでき、ＩＣ等の小さい２次元コード５２を必要とする用途にも広く使用できるようになる。
また、サイズコード６０〜８２は、例えば、２次元コード５２の情報を表しているデータセルと同じ様式のセルの分布パターンで表されるので、２次元コード読取装置２もソフト的に容易に、２次元コード５２のサイズ（ここではデータセルの方向と範囲）を決定することが可能となる。したがって、位置決め用シンボル５４，７６，８６のように、変化点検出回路１８、比検出回路２０およびアドレス記憶メモリ２２と言ったハードを特別に備えなくても、従来の２次元コード読取装置でも、プログラムを変更するのみで対処できる。
【００７５】
更に、サイズコード６０〜８２は、２次元コード５２のサイズを、最初に位置や形状が検出される位置決め用シンボル５４のサイズに対する比率で表しているので、位置決め用シンボル５４が最初にその位置や大きさが決定された後、この位置決め用シンボル５４の大きさを基準として、比率で２次元コード５２のサイズを検出すれば、迅速・容易に２次元コード５２のサイズを決定することができる。
【００７６】
この比率は、本実施の形態では、分数で表していたが、例えば、２倍、３倍、４倍、……等の整数あるいは、１．７倍、２．７倍、３．３倍、……等の小数で表すものであっても良い。
また、本実施の形態ではサイズコード６０〜８２の種類も３種類であったが、１種類または２種類でも良く、４種類以上でも良い。
【００７７】
また、本実施の形態ではサイズコード６０〜８２は、６セルが直線状に配列されたものであったが、マトリックス状に配列されたものでも良く、セル数も必要に応じて増減できる。
【００７８】
本実施の形態では、サイズコード６０〜８２は、位置決め用シンボル５４から１セル離れた隣接位置に配置されていたので、少ない誤差でサイズコード６０〜８２が検出でき、２次元コードの解読処理が、より正確かつ迅速となるが、２次元コード内での配置としては、予め決定しておけば、位置決め用シンボル５４から２セル以上離れた近傍位置あるいは位置決め用シンボル５４とは反対側の２次元コード５２の端部あるいはこの端部に近い位置でも良い。
【００７９】
また、位置決め用シンボル５４は、複数の異なる方向または複数の異なる位置において走査した場合に特定の周波数成分比が得られるパターンであるので、走査によりハード的にもソフト的にも迅速に位置決め用シンボルが検出できる。
また、２次元コード５２が正方形をなし、サイズコード６０〜８２の配置そのものが、データセルの存在方向を表しているので、特に、データセルの存在方向を示すマーク等が必要ない。
【００８０】
また、２次元コード５２が長方形であれば、２つのサイズコード６０〜８２を２次元コード５２の縦と横とのサイズを表すものとしても良い。
本実施の形態では、２次元コード５２と位置決め用シンボル５４とが正方形であり、２つのサイズコード６０〜８２が表す比率は同一となることから、２次元コード５２に対して、いずれか一方のサイズコード６０〜８２の配置を省略しても良い。ただし、この場合でも、配置が省略されたサイズコード６０〜８２が示すべきデータセルの存在方向を、存在するサイズコード６０〜８２に対していずれの方向であるかを、予め決定しておく必要がある。
【００８１】
本実施の形態において、ＣＣＤ４、２値化回路６、クロック信号出力回路１４、タイミングにアドレス発生回路１６、変化点検出回路１８および比検出回路２０が行う処理と制御回路２８が行うステップＳ１００，Ｓ１２１とが２次元コード位置決め処理に該当し、ステップＳ１２３，Ｓ１２５がサイズ取得処理に該当し、ステップＳ１４０がデコード処理に該当する。
【００８２】
［その他］
前記実施の形態では、位置決め用シンボル５４，７６，８６を二重の正方形で、中心を横切る周波数成分比が黒：白：黒：白：黒＝１：１：３：１：１の図形で表していたが、図１２（ａ）のように円形でもよく、図１２（ｂ）のように六角形でもよく、また他の正多角形でも良い。即ち、同心状に相似形の図形が重なり合う形に形成したものであればよい。さらに、中心を横切る周波数成分比があらゆる角度で同じならば、図１２（ｃ）に示すごとく、図形を何重にしても良い。更に、位置決め用シンボル５４，７６，８６は、上述のような周波数成分比で表されるものでなくても、ハード的あるいはソフト的に検出し易く、区別し易い形状であれば、他の形状でも良い。
【００８３】
位置決め用シンボルの配置数や間隔は、シンボルの検出し易さや歪みの反映の程度、必要なデータ量の確保の点から適宜決定する。
また、前記実施の形態では位置決め用シンボル５４，７６，８６は、２次元コード５２，７４，８４の４つの頂点の内、１つに配置されていたが、２次元コード５２，７４，８４内での配置は任意である。また必要なら１つの２次元コード５２，７４，８４に２つの位置決め用シンボルを設けても良い。例えば、図１３に示すごとく、２次元コード９２の隣接する頂点に、２つの位置決め用シンボル９３，９４を配置し、データ領域９６に、サイズコード９７，９８を設けても良い。サイズコード９７，９８は、位置決め用シンボル９３，９４に対して、それぞれ位置決め用シンボル９３，９４が存在しない隣接する２次元コード９２の頂点側に配置されているので、この方向における２次元コード９２のサイズを決定している。そして、そのサイズコード９７，９８の種類から図の縦方向のサイズは２１セルであることが判る。なお、図の横方向のサイズは、位置決め用シンボル９３，９４の配置により決定されているので、サイズコードの配置は不要である。
【図面の簡単な説明】
【図１】 実施の形態における２次元コード読取装置の概略構成を表すブロック図である。
【図２】 実施の形態における２次元コードの一例の概略構成説明図である。
【図３】 実施の形態における２次元コードの一例の詳細構成説明図である。
【図４】 実施の形態における位置決め用シンボルを走査した場合の明暗検出の説明図である。
【図５】 実施の形態におけるＣＣＤと２値化回路との出力信号の説明図である。
【図６】 実施の形態におけるサイズコードの種類の説明図である。
【図７】 実施の形態における２次元コードの小さい例の概略構成説明図である。
【図８】 実施の形態における２次元コードの大きい例の概略構成説明図である。
【図９】 実施の形態における２次元コード読取処理のフローチャートである。
【図１０】 実施の形態における処理手順説明図である。
【図１１】 実施の形態における処理手順説明図である。
【図１２】 位置決め用シンボルの他の形状の例を示す説明図である。
【図１３】 他の２次元コードの一例の概略構成説明図である。
【図１４】 従来のバーコードおよび２次元コードの説明図である。
【図１５】 従来の２次元コードの概略構成説明図である。
【図１６】 従来の２次元コードの詳細構成説明図である。
【符号の説明】
２…２次元コード読取装置 ４…ＣＣＤ ６…２値化回路
８…画像メモリ １４…クロック信号出力回路
１６…アドレス発生回路 １８…変化点検出回路 ２０…比検出回路
２２…アドレス記憶メモリ ２８…制御回路
５２，７４，８４，９２…２次元コード
５４，７６，８６，９３，９４…位置決め用シンボル
５６，７８，８８，９６…データ領域
６０，６２，７０，７２，８０，８２，９７，９８…サイズコード[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-dimensional code and a two-dimensional code reading method.
[0002]
[Prior art]
Conventionally, as an example of a proposed two-dimensional code, there is one disclosed in Japanese Patent Laid-Open No. 7-254037, and as an example of this two-dimensional code reader, there is one disclosed in Japanese Patent Laid-Open No. 8-180125.
[0003]
The two-dimensional code has a two-dimensional spread of information as shown in FIG. 14B, and can record a much larger amount of information than the barcode shown in FIG. 14A, but the structure is complicated. Therefore, it is important to quickly determine the entire shape of the two-dimensional code.
[0004]
Therefore, in the conventional two-dimensional code, as shown in FIG. 15, three positioning symbols 310 a, 310 b, and 310 c combined with squares having a specific size ratio are respectively set to three vertices among the four vertices of the two-dimensional code 300. Arranged.
The positioning symbols 310a, 310b, and 310c include, for example, a black frame-shaped square 312 whose length of one side corresponds to 7 cells, a white frame-shaped square 314 whose length of one side corresponds to 5 cells, and a length of one side. A figure formed by concentrically overlapping black squares 316 corresponding to three cells is employed.
[0005]
When the vicinity of the center of the positioning symbols 310a, 310b, 310c is linearly crossed, black, white, black, date, and black patterns are detected at a ratio of 1: 1: 3: 1: 1. Since the detection of such a ratio can be detected relatively easily in terms of hardware and software, when black and white are alternately detected at the above ratio, the pattern is determined to be the dominant of the positioning symbols 310a, 310b, 310c. It is possible to quickly determine that it is a candidate, and it is possible to quickly determine its position and shape.
[0006]
If the positions and shapes of the three positioning symbols 310a, 310b, and 310c can be quickly determined in this way, each vertex of the two-dimensional code 300 is determined, and the contents of the data cell 330 constituting the two-dimensional code 300 are determined. Can be read quickly and accurately. (In FIG. 15, the black and white pattern of the data cell 330 is omitted.)
Therefore, the presence of these three positioning symbols 310a, 310b, and 310c is important for quickly and accurately determining the location of the two-dimensional code 300.
[0007]
[Problems to be solved by the invention]
Thus, in order to decode a two-dimensional code recording a large amount of data in a short time, conventionally it was necessary to have three positioning symbols, but the amount of information recorded in the two-dimensional code is compared. However, the conventional two-dimensional code cannot always be said to have a suitable configuration.
[0008]
For example, in the above-described two-dimensional code 300, when the amount of information decreases, the ratio of the area of the positioning symbols 310a, 310b, and 310c to the total area of the two-dimensional code 300 increases. In an extreme case, as shown in FIG. The three positioning symbols 410a, 410b, and 410c occupy most of the entire area of the two-dimensional code 400, and there is a problem that the two-dimensional code is hardly reduced even if the amount of information is reduced. Therefore, although the amount of information is small, a large area is required in a portion other than the information, so that it is not possible to meet the demand for space saving by reducing the two-dimensional code according to the application. For example, although there is a demand for printing a small two-dimensional code by reducing the amount of information in a small space such as a resin surface of an IC, there is one aspect that it cannot be met.
[0009]
In order to solve such a problem, it is conceivable to reduce the number of positioning symbols. For example, in Japanese Patent Application Laid-Open No. 2-56091, only one positioning symbol is arranged on the assumption that a certain range is the size of the two-dimensional code from one positioning symbol placed in the center of the two-dimensional code. Absent.
[0010]
However, since the two-dimensional code described in Japanese Patent Laid-Open No. 2-56091 has one positioning symbol, the overall size must be constant in advance, and even when the amount of information is further reduced That constant size is required. Therefore, the demand for further reducing the space by reducing the two-dimensional code depending on the application cannot be met.
[0011]
Further, even when reading processing is performed, a predetermined range must be read, so that even if the amount of data is small, it cannot be said that reading processing can be performed quickly.
On the contrary, even if only the two-dimensional code is enlarged to increase the amount of information, the reading process only reads a predetermined range, so reading is necessary to deal with the enlarged two-dimensional code. There is a problem in that the hardware and software configuration of the reading apparatus that performs processing must be changed, and it cannot be quickly dealt with depending on the application.
[0012]
An object of the present invention is to provide a two-dimensional code whose size can be easily changed according to the application and a reading method thereof.
[0013]
[Means for Solving the Problems and Effects of the Invention]
  The two-dimensional code of the present invention provides a 1: 1: 3: 1: 1 frequency component ratio when scanned in a plurality of different directions or in a plurality of different positions.Square shapePattern,squareIn addition to the positioning symbol that specifies the position of the two-dimensional code of the shape, a predetermined position relative to the positioning symbolAnd each of the four sides of the positioning symbol at a position along two sides on the side where the data cell exists.Arranged and represents the size of the two-dimensional code with the cell distribution patternTwoA size code is provided. The size code is arranged by selecting a distribution pattern indicating the size of the two-dimensional code from a plurality of size codes having different distribution patterns for a predetermined number of cells.
[0014]
For this reason, even if there is only one positioning symbol, the size of the two-dimensional code can be determined from the size code information, so that the reading device can specify the size to be read. In this way, the reading device side only reads the size of the two-dimensional code from the size code information, and thereafter, even if the size of the two-dimensional code is changed, the hardware or software can be changed. The two-dimensional code can be read accurately without any unnecessary reading or reading spillage.
[0015]
Since the size code is not a pattern that is detected first like a positioning symbol, it only needs to represent the size, so it occupies a relatively small area and is almost a hindrance even when the two-dimensional code is reduced. It will not be.
Further, the above description means that the size of the two-dimensional code can be freely changed only by changing the contents of the size code, and the size of the two-dimensional code can be quickly dealt with according to the application.
[0016]
Further, since the size of the two-dimensional code is read from the contents of the size code, not from the positioning state of the positioning symbols, there is no need for three positioning symbols, and two or one is required. However, the size of the two-dimensional code can be easily detected. For this reason, the number of positioning symbols can be reduced, and even in applications where a small-sized two-dimensional code is required, the two-dimensional code is mostly occupied by three positioning symbols and cannot be reduced. By solving this problem, the two-dimensional code can be made sufficiently small. Therefore, it can be widely used for applications that require a small two-dimensional code such as an IC.
[0017]
  furtherThe size code is2It can be expressed by the cell distribution pattern in the same format as the data cell that represents the dimension code information.ForThe reading device can also easily read the size of the two-dimensional code in terms of software. Therefore, even a conventional two-dimensional code reader can cope with the problem only by changing the program.
[0018]
  The size of the two-dimensional code represented by the size code isSquareIt may be expressed as a ratio to the size of the positioning symbol. Since the position and shape of the positioning symbol are determined first, the size of the two-dimensional code can be quickly and easily detected by detecting the size of the two-dimensional code by the ratio based on the shape of the positioning symbol. Can be determined. For example, it is 2 times, 3 times, 4 times,..., Etc. of the positioning symbol, and not only an integer number but also 1.7 times, 2.7 times, 3.3 times, 15/7 times, 23 / It may mean a fractional or fractional multiple such as 7 times,.
[0019]
ExampleFor example, the size code cell distribution pattern is associated with the ratio, and the reader determines the size of the two-dimensional code by obtaining the ratio from the read size code cell distribution pattern based on the correspondence table. Read the contents of the data cell from the size.
[0020]
NaFor example, the arrangement of the size code in the two-dimensional code is adjacent to the positioning symbol.ArrangePlaced. Thus, the positioning symbolInadjacentExistThus, the positioning error of the size code is smaller than that at a distant position. Therefore, since the size code is accurately detected based on the position of the positioning symbol, the two-dimensional code decoding process becomes more accurate and rapid.
[0022]
AlsoFor example, one positioning symbol may be arranged at any one of the four vertices of the two-dimensional code, and the size code may represent the vertical and horizontal sizes of the two-dimensional code.
  For example, if the rectangle is a square, the vertical and horizontal sizes are the same, so the size code may represent one size.
[0023]
Two size codes are arranged on each of the four sides of the positioning symbol on the side where the data cell exists, and each size code is a two-dimensional code on each side of the arranged positioning symbol. It is good also as a structure showing a size. With this configuration, if the position of the size code is detected, the direction in which the data cell exists and the range thereof can be determined at the same time, so that processing can be performed efficiently.
[0024]
In this case, if the two-dimensional code is a square, the sizes represented by the two size codes are the same. Therefore, it is not necessary to omit one of the size codes. However, even in this case, it is necessary to determine in advance which direction the existence direction of the data cell to be indicated by the omitted size code is with respect to the size code that is not omitted.
[0025]
When two size codes representing the same size are provided, the error processing is executed by comparing whether or not the two are the same at the time of the reading process, and assuming that it is a reading error if they are not the same. Also good.
Examples of the method for reading the above-described two-dimensional code include the following methods.
[0026]
  First, a two-dimensional code image is obtained by scanning a two-dimensional code or the like, and performing a two-dimensional code positioning process for detecting a positioning symbol in the image. Next, based on the detected positioning symbolTDetect the Izu code and thisBy detecting the distribution pattern of the cells forming the size code and decoding this distribution pattern,A size acquisition process for acquiring the size of the two-dimensional code represented by the size code is performed. Next, based on the acquired size of the two-dimensional code, a decoding process for reading the information of the two-dimensional code is performed.
[0027]
Thus, in the size acquisition process, the size of the two-dimensional code represented by the size code is acquired, and based on the size of the two-dimensional code, the information of the two-dimensional code is read in the decoding process. Therefore, even if the size of the two-dimensional code from which information is to be read changes for each two-dimensional code, it can be immediately handled by the size code included in each two-dimensional code, and the information of the two-dimensional code can be read wastefully. It can be read accurately without reading or spilling.
[0028]
More specifically, it can be configured as follows. That is, in the two-dimensional code positioning process, a two-dimensional code image is obtained by scanning the two-dimensional code, and the position and shape of the positioning symbol in the image are detected. The size acquisition processing detects the position of the size code (predetermined position with respect to the positioning symbol) based on the detected position and shape of the positioning symbol, and detects the distribution pattern of the cells forming the size code from this position. Then, by decoding this distribution pattern, the size of the two-dimensional code represented by the size code is acquired. The decoding process detects the position of the data cell representing the information of the two-dimensional code based on the acquired size of the two-dimensional code and the shape of the positioning symbol, and reads the information of the two-dimensional code from this position.
[0029]
The two-dimensional code is arranged on each of the two sides where the data cell exists among the four sides of the positioning symbol, and each size code is on each side of the arranged positioning symbol. The following two-dimensional code reading method may be employed if the data cell size is represented.
[0030]
That is, a two-dimensional code image is obtained by scanning the two-dimensional code, and a two-dimensional code positioning process for detecting the position and shape of the positioning symbol in the image is performed. Next, the detected positioning is performed. The presence of two size codes is detected by inspecting the predetermined positions on the four sides of the positioning symbol based on the position and shape of the symbol for use, and the size of the two-dimensional code represented by this size code is determined. Perform the size acquisition process to be acquired, and then, for each of the two sides of the positioning symbol for which the size code is detected, based on the size of the two-dimensional code acquired from the size code and the shape of the positioning symbol, The position of the data cell is detected, and a decoding process for reading the information of the two-dimensional code from the data cell is performed.
[0031]
Note that the function of executing such a two-dimensional code reading method is provided as a program that is activated on the computer system side, for example. In the case of such a program, for example, it is stored in a machine-readable storage medium such as a floppy disk, a magneto-optical disk, a CD-ROM, or a hard disk, and is used by being loaded into a computer system and started up as necessary. it can. In addition, the ROM or backup RAM may be stored as a machine-readable storage medium, and the ROM or backup RAM may be incorporated into a computer system.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
The block diagram of FIG. 1 shows a schematic configuration of a two-dimensional code reader 2 to which the above-described invention is applied.
The two-dimensional code reader 2 includes a CCD 4, a binarization circuit 6, an image memory 8, a clock signal output circuit 14, an address generation circuit 16, a change point detection circuit 18, a ratio detection circuit 20, an address storage memory 22, and a control circuit 28. It is composed of
[0033]
The control circuit 28 is configured as a computer system including a CPU, a ROM, a RAM, an I / O, and the like, and executes a two-dimensional code reading process, which will be described later, according to a program stored in the ROM. 2 is controlled.
[0034]
Here, FIG. 2 shows a schematic diagram of an example of a two-dimensional code to which the above-described invention detected by the two-dimensional code reader 2 is applied. The two-dimensional code 52 is printed on a white mount 53, and is composed of one positioning symbol 54, a data area 56, and two size codes 60 and 62. The overall size is a square shape of 15 cells × 15 cells. Each cell is selected from two types of optically different cells. In the drawings and description, the cells are distinguished by white (bright) and black (dark). In FIG. 2, the black and white pattern of the data cells in the data area 56 is omitted for convenience. The actual two-dimensional code 52 is as shown in FIG. 3 as an example.
[0035]
The positioning symbol 54 is arranged at one of the four vertices of the two-dimensional code 52. As shown in FIG. 4 (A), the light and dark arrangement of the positioning symbol 54 cell is a reduced frame-shaped square made of white having a width of 1 cell at the center of the frame-shaped square 55a made of black having a width of 1 cell. 55b is formed, and a square 55c having a size of 3 cells × 3 cells made of black is formed in a central portion inside thereof.
[0036]
The size codes 60 and 62 are adjacent positions separated by one cell from the positioning symbol 54 in the data area 56, and two sides 54a and 54b of the positioning symbol 54 on the side where the data area 56 exists. Are arranged along. Each of the size codes 60 and 62 has a configuration in which six cells are arranged in series. The size codes 60 and 62 are arranged such that black cells and white cells are alternately arranged from the left side when viewed from the data area 56. The size codes 60 and 62 represent the size information of the two-dimensional code 52 by the cell distribution pattern of this array.
[0037]
As the cell distribution pattern that can be set as the size code, 2 6 = 64 types can be provided. Here, it is assumed that only three types of size codes are determined. In particular, three types of patterns shown in FIGS. 6A, 6B, and 6C are used so that the distribution of black cells and white cells is not biased. Among these, FIG. 6A corresponds to the size codes 60 and 62 used in FIG. 2, and represents 15/7 as size information. This size information represents the ratio (here, magnification) of the two-dimensional code 52 to the size of the positioning symbol 54. That is, the positioning symbol 54 in FIG. 2 is a square, and the length of one side is 7 cells. Therefore, it can be seen from the size codes 60 and 62 that the length of one side of the two-dimensional code 52 is 7 cells × 15/7 = 15 cells.
[0038]
In addition, since the size codes 70 and 72 in FIG. 6B represent the ratio 11/7, as shown in FIG. 7, 2 is 11/7 (11 cells) with respect to the size of the positioning symbol 76. Used for the dimension code 74.
In addition, since the size codes 80 and 82 in FIG. 6C represent the ratio 21/7, as shown in FIG. 8, the size of the positioning symbol 86 is 21/7 (21 cells). Used for the dimension code 84.
[0039]
Here, on the assumption that the two-dimensional code 52 and the positioning symbol 54 are square, the two size codes 60 and 62 are exactly the same. However, if the two-dimensional code 52 or the positioning symbol 54 includes a non-square rectangle or a rectangular shape such as a parallelogram in some cases, for example, the size code 60 on the side 54a side is a positioning symbol. 54 represents the ratio of the size in the x direction of the two-dimensional code 52 to the size in the x direction of 54, and the size code 62 on the side 54b side of the two-dimensional code 52 with respect to the size in the y direction of the positioning symbol 54 It is assumed that the size ratio in the y direction is expressed.
[0040]
The control circuit 28 performs two-dimensional code reading control as described below.
First, in accordance with an instruction from the control circuit 28, a two-dimensional image of a place where the two-dimensional code 52 passes is detected by the CCD 4 as a two-dimensional image detection means. When detecting a two-dimensional image, the CCD 4 outputs two-dimensional image data with a signal having an analog level as shown in FIG. The two-dimensional image data is binarized by the binarizing circuit 6 at the threshold value instructed from the control circuit 28, and two levels of 1 (high) / 0 (low) as shown in FIG. Convert to a signal consisting of
[0041]
On the other hand, the clock signal output circuit 14 outputs a clock pulse sufficiently finer than the pulse of the two-dimensional image data output from the CCD 4 according to the synchronization pulse output from the CCD 4. The address generation circuit 16 counts the clock pulses and generates an address for the image memory 8. The binarized two-dimensional image data is written in units of 8 bits for each address.
[0042]
On the other hand, the change point detection circuit 18 outputs a pulse signal to the ratio detection circuit 20 when the signal from the binarization circuit 6 changes from “1” to “0” or from “0” to “1”. To do. The ratio detection circuit 20 counts the clock pulses output from the clock signal output circuit 14 from the input of the pulse signal from the change point detection circuit 18 to the input of the next pulse signal, thereby increasing the brightness ( Determine the continuous length of 1) and the continuous length of dark (0). From this length ratio, a pattern corresponding to the positioning symbol 54 of the two-dimensional code 52 is detected.
[0043]
As shown in FIG. 4A, the light-dark pattern on the scanning lines (a), (b), and (c) of the CCD 4 that crosses substantially the center of the positioning symbol 54 at a representative angle is shown in FIG. As shown in Fig. 4, all have the same light / dark component ratio. That is, the light / dark component ratio of each scanning line (a), (b), (c) crossing the center of the positioning symbol 54 is dark: bright: dark: bright: dark = 1: 1: 3: 1: 1. It has become. Of course, the ratio is 1: 1: 3: 1: 1 even in the scanning line having an intermediate angle between the scanning lines (a), (b), and (c). 4A is arranged on an oblique surface when viewed from the CCD 4 side, the light / dark component ratio of the scanning lines (a), (b), and (c) is dark: bright: Dark: light: dark = 1: 1: 3: 1: 1. FIG. 4B corresponds to the binarized signal from the binarization circuit 6.
[0044]
As a result, the ratio detection circuit 20 detects the light / dark component ratio of “1: 1: 3: 1: 1”, and if detected, the image memory generated by the address generation circuit 16 at that timing. 8 addresses are stored in the address storage memory 22.
Therefore, when the CCD 4 detects two-dimensional image data for one frame, the image memory 8 stores the binarized two-dimensional image data, and the address storage memory 22 stores the detected positioning symbols. 54 addresses are stored.
[0045]
When an image for one frame of the first two-dimensional image is obtained, the control circuit 28 performs a two-dimensional code reading process, which will be described later, based on the data in the image memory 8 and the address storage memory 22, and this process ends. Then, the control circuit 28 instructs the CCD 4 to detect the next one-frame two-dimensional image. Therefore, a two-dimensional image is output from the CCD 4 to the binarization circuit 6 again, and the processing as described above is repeated.
[0046]
Next, after the image of the two-dimensional code 52 for one frame and the address of the positioning symbol 54 are stored in the image memory 8 and the address storage memory 22 respectively, the control circuit 28 performs the two-dimensional code reading process. Execute. This two-dimensional code reading process is shown in the flowchart of FIG.
[0047]
When the processing is started, first, the positioning symbol 54 is detected (S100).
In this processing, the image memory 8 and the address storage memory 22 are accessed, and whether or not the positioning symbol 54 exists at an appropriate position from the stored contents and the positioning symbol 54 is accurately displayed on the image. The correct shape and center position are determined.
[0048]
In this process, first, it is determined with reference to the address value and the image in the image memory 8 whether the address of the positioning symbol 54 stored in the address storage memory 22 is positionally divided into one group. .
Next, in step S100, it is determined whether or not only one appropriate positioning symbol 54 has been detected (S110). If not detected (“NO” in S110), the next image is detected by the CCD 4. Instructed (S180), the process is terminated.
[0049]
When one appropriate positioning symbol 54 is detected (“YES” in S110), it is next determined whether or not it is a new two-dimensional code 52 (S120). This process is to prevent the two-dimensional code 52 detected before the previous time from being decoded as another two-dimensional code when it is still being detected by the CCD 4. For example, if an appropriate positioning symbol 54 has been detected in the previous process or a predetermined number of times before, and the code content has already been read appropriately, the same two-dimensional code 52 is detected. As a result ("NO" in S120), the CCD 4 is instructed to detect the next image (S180), and the process is terminated.
[0050]
If it is determined that the code is the new two-dimensional code 52 (“YES” in S120), then the shape and center of each cell constituting the positioning symbol 54 from the 1 (white) / 0 (black) pattern in the image memory 8 The position is calculated (S121).
This will be specifically described. Assume that an image of the two-dimensional code 52 is obtained as shown in part in FIG. Among the images of the positioning symbols 54, the addresses stored in the address storage memory 22 have the light / dark component ratios detected as dark: bright: dark: bright: dark = 1: 1: 3: 1: 1. This corresponds to the image of the portion Ls (here, 9 corresponds). Therefore, based on the address, the portion corresponding to the square 55c of black of the size of 3 cells × 3 cells inside the positioning symbol 54 in the light / dark component ratio, that is, the dark component ratio is “3”. It is possible to specify the position on the image of the portion (image portions Ls0 to Ls8 represented by a dashed line in the square 55c).
[0051]
Then, the image portion Ls0 at the head address and the image portion Ls8 at the tail address are selected, and the addresses of the end points A01 and A02 of the head image portion Ls0 and the end points of the tail image portion Ls8 are selected. The addresses A11 and A12 are obtained. Then, the address is converted into an image coordinate system (here, as shown, an xy coordinate system having the upper left as the origin).
[0052]
The coordinates of the center point Ac0 of the end points A01 and A02 and the center point Ac1 of the end points A11 and A12 are obtained. Next, the center coordinates of both center points Ac0 and Ac1 are obtained and set as the center coordinates Sc (Xa, Ya) of the image of the positioning symbol 54.
Next, out of the four end points A01, A02, A11, and A12 described above, end points A02 and A11 that are close to the vertex of the black square 55c are extracted. That is, in each of the image portions Ls0 and Ls8, it is determined by determining which end point is close to the vertex of the black square 55c.
[0053]
For example, in the area E0 adjacent on the side where the address is smaller than the head image portion Ls0, the address recognized as black is biased toward the end point A01 far from the apex of the square 55c, as indicated by the alternate long and short dash line. Further, in the area E1 adjacent on the side where the address is larger than the last image portion Ls8, as indicated by the alternate long and short dash line, the address recognized as black is biased toward the end A12 far from the apex of the square 55c.
[0054]
Therefore, by determining the black arrangement bias at the addresses corresponding to the areas E0 and E1 adjacent to the outside of the scanning line portion Ls, the end points A02 and A11 on which black is not biased are determined as the vertices of the square 55c. Can be extracted as an end point close to. It should be noted that the two end points A02 and A11 are the end points described above for either one of the two end points A02 and A11 without being individually determined as the end points close to the apex of the square 55c in the above-described processing. If it can be determined that it is close to the apex of the square 55c in the process of (2), since the end point that is diagonally opposite to the determined end point is close to the apex of the square 55c, the end point that exists diagonally is determined. You can just extract it.
[0055]
Next, the straight line connecting the two end points A02 and A11 is multiplied by 1.5 and the end extended to the end point A02 side is set as the temporary center position f ′ of the apex cell of the black frame-like square 55a. On the contrary, the end extended to the end point A11 side is set as a temporary center position g ′ of the apex cell of the black frame-like square 55a.
[0056]
Next, the peripheral images of the temporary center positions f ′ and g ′ are examined closely, and the accurate vertex cell center positions f and g are determined from the characteristics of the shape of the black edge of the vertex of the frame-like square 55a. Ask.
Next, the center positions h and i of the remaining two vertex cells of the frame-like square 55a are the ends of straight lines of the same length perpendicular to the straight line connecting the center positions f and g and at the center Sc. Therefore, the coordinates h (Xh, Yh), i (Xi, Yi) of the center positions h, i are changed to the coordinates f (Xf, Yf), g (Xg, Yg) and the center of the center positions f, g. It is obtained by calculation based on the coordinates Sc (Xa, Ya).
[0057]
As shown in FIG. 11, one vertex cell center position h (Xh, Yh) is an intersection point Sh, a center position h, and a center Sc of a perpendicular line from the center position h with respect to a horizontal line Lv passing through the center Sc of the positioning symbol 54. Based on the relationship between the triangle having the vertices and the intersection Sf of the perpendicular line from the center position f to the horizontal line Lv and the triangle having the vertices of the center position f and the center Sc have the same shape, It is obtained by solving simultaneous equations.
[0058]
[Expression 1]

[0059]
The other vertex cell center position i (Xi, Yi) can also be obtained by solving the following simultaneous equations from the same relationship.
[0060]
[Expression 2]

[0061]
Each of the peripheral images of the center positions h and i of the two vertex cells thus obtained is scrutinized, and an accurate center coordinate of the vertex cell is obtained from the shape of the edge of the vertex of the frame-like square 55a. Formally, the coordinates of the center positions h and i are used.
Then, by dividing the center positions h, f, i, and g of adjacent vertex cells into six equal parts, the center position of the cells constituting the black frame-like square 55a and the size of one cell are determined.
[0062]
Thus, the shape of the positioning symbol 54 and the center position Sc are determined.
Next, the size code 60, 62 is detected based on the positioning symbol 54 (S123).
First, as shown in FIG. 11, end points F and G obtained by extending a straight line connecting the center positions f and g of the vertex cells on the diagonal to each vertex side by 1/3 of the length of the straight line are obtained. Similarly, end points H and I obtained by extending a straight line connecting the center positions h and i of the vertex cells on the diagonal to each vertex side by 1/3 of the length of the straight line are obtained.
[0063]
Among the end points F, G, H, and I, the cell contents are read by tracing between the adjacent end points H and F in a straight line. That is, the process of reading the cell contents along the side 54d is performed at a position 1.5 cells away from the side 54d of the positioning symbol 54. Similarly, between the adjacent end points F and I along the side 54a, between the adjacent end points I and G along the side 54b, and between the adjacent end points G and H along the side 54c, respectively. Processing to read the contents of the cell is performed.
[0064]
As shown in FIG. 2, the size codes 60 and 62 are arranged one cell apart along two adjacent sides 54 a and 54 b of the positioning symbol 54. That is, the position separated by 1.5 cells from the two sides 54a and 54b passes through the center position of the cells of the size codes 60 and 62.
[0065]
Accordingly, any of the size codes shown in FIG. 6 is detected by the two reading processes by the four reading processes between the end points F, G, H, and I.
Next, it is determined whether or not two identical size codes are detected (S124). If only one code is detected, three or more are detected, no size code is detected, or no size code is detected. If both contents are different ("NO" in S124), the process proceeds to step S180 as an error.
[0066]
If only two identical size codes are detected (“YES” in S124), then the shape of the two-dimensional code 52 is determined (S125).
That is, based on the position and contents of the size codes 60 and 62 read in step S123, on which side the data cell exists with respect to the positioning symbol 54, and to what size it is expanded To decide.
[0067]
That is, it is determined that a data cell exists in the direction of the side where the size codes 60 and 62 are detected among the sides 54a to 54d of the positioning symbol 54. Then, the ratio is determined from the types of the obtained size codes 60 and 62, and it is determined how many times the two-dimensional code 52 is the size of the positioning symbol 54. Here, since the size codes 60 and 62 having the ratio of 15/7 are obtained, the two-dimensional code 52 is determined to be the size 15 cells × 15 cells shown in FIG.
[0068]
Next, the position of each data cell is determined, and the monochrome type of the data cell is determined (S140). That is, the size of one cell of the positioning symbol 54 determined in step S121 and the size of the positioning symbol 54 from the position of the positioning symbol 54 to the sides 54a and 54b, respectively, including the size of the positioning symbol 54. The center position of each data cell in the range is calculated and obtained, and the black or white type of each data cell is read and decoded from the center position, and information represented by the two-dimensional code 52 is obtained.
[0069]
Next, it is determined whether or not the code content is normal (S160). For example, whether or not the number of cells of white and black is a predetermined number, or the result of calculating the data represented by a predetermined calculation method is a predetermined position of the two-dimensional code 52 It is determined whether or not the code is normally read by checking whether or not it matches the displayed data.
[0070]
If the code is not normal (“NO” in S160), the CCD 4 is instructed to detect the next image (S180), and the process is terminated.
If the code is normal (“YES” in S160), the code content is output to another device such as a host computer, the code content is stored in a specific memory, or a process corresponding to the code content is performed. A process of executing or outputting an instruction corresponding to the code content is performed (S170).
[0071]
Then, in order to read the next new two-dimensional code, the CCD 4 is instructed to detect an image (S180), and the process is terminated.
Note that the 11-cell × 11-cell two-dimensional code 74 (FIG. 7) whose size is represented by other size codes 70 and 72 and the 21-cell × 21-cell whose size is represented by size codes 80 and 82. With respect to the two-dimensional code 84 (FIG. 8), the contents of the data areas 78 and 88 can be accurately read by the same processing without wasteful reading or spilling. Each positioning symbol 76, 86 is the same as the positioning symbol 54 of the two-dimensional code 52 in FIG.
[0072]
In the present embodiment, as described above, the size codes 60, 62, 70, 72, 80, 82 are arranged at positions adjacent to the two sides 54a, 54b of the positioning symbol 54, and the positioning symbol 54 is If detected, the size code 60-82 is immediately detected based on the shape and position of the positioning symbol 54, and the direction and range in which the data cell exists according to the position and content of the size code 60-82. Is determined.
[0073]
For this reason, even if there is only one positioning symbol 54, it is immediately determined in what position and in what range the data cell is located with respect to the positioning symbol 54, and the information of the two-dimensional code 52 is wasted. It can be read accurately without reading or spilling.
[0074]
Therefore, even in applications where a small size of the two-dimensional code 52 is required, the three positioning symbols 54 need not be used in the two-dimensional code 52. The limit of miniaturization of the code 52 can be made sufficiently small, and it can be widely used in applications that require a small two-dimensional code 52 such as an IC.
In addition, since the size codes 60 to 82 are represented by, for example, a cell distribution pattern in the same format as the data cell representing the information of the two-dimensional code 52, the two-dimensional code reader 2 can be easily softwareized. It is possible to determine the size of the two-dimensional code 52 (here, the direction and range of the data cell). Therefore, even if the conventional two-dimensional code reader is not provided with hardware such as the change point detection circuit 18, the ratio detection circuit 20, and the address storage memory 22 like the positioning symbols 54, 76, 86, It can be dealt with just changing the program.
[0075]
Furthermore, since the size codes 60 to 82 represent the size of the two-dimensional code 52 as a ratio to the size of the positioning symbol 54 from which the position or shape is first detected, the positioning symbol 54 first displays its position or After the size is determined, the size of the two-dimensional code 52 can be quickly and easily determined by detecting the size of the two-dimensional code 52 by using the size of the positioning symbol 54 as a reference.
[0076]
In the present embodiment, this ratio is represented by a fraction, but for example, an integer such as 2 times, 3 times, 4 times,..., 1.7 times, 2.7 times, 3.3 times, It may be expressed in decimals such as.
In this embodiment, there are three types of size codes 60 to 82, but one or two types may be used, and four or more types may be used.
[0077]
  In the present embodiment, the size codes 60 to 82 are such that 6 cells are arranged in a straight line, but may be arranged in a matrix, and the number of cells can be increased or decreased as necessary..
[0078]
In the present embodiment, since the size codes 60 to 82 are arranged at adjacent positions one cell away from the positioning symbol 54, the size codes 60 to 82 can be detected with a small error, and the decoding process of the two-dimensional code can be performed. However, if it is determined in advance as the arrangement in the two-dimensional code, the two-dimensional code is located in the vicinity of two or more cells away from the positioning symbol 54 or on the side opposite to the positioning symbol 54. The end of the cord 52 or a position close to this end may be used.
[0079]
Further, since the positioning symbol 54 is a pattern in which a specific frequency component ratio is obtained when scanning is performed in a plurality of different directions or a plurality of different positions, the positioning symbol 54 can be quickly positioned both in terms of hardware and software by scanning. Can be detected.
In addition, since the two-dimensional code 52 is square and the arrangement of the size codes 60 to 82 indicates the direction in which the data cell exists, there is no need for a mark or the like indicating the direction in which the data cell exists.
[0080]
If the two-dimensional code 52 is a rectangle, the two size codes 60 to 82 may represent the vertical and horizontal sizes of the two-dimensional code 52.
In the present embodiment, the two-dimensional code 52 and the positioning symbol 54 are square, and the ratios represented by the two size codes 60 to 82 are the same. The arrangement of the size codes 60 to 82 may be omitted. However, even in this case, it is necessary to determine in advance which direction the existence direction of the data cell to be indicated by the size codes 60 to 82 whose arrangement is omitted is with respect to the existing size codes 60 to 82. There is.
[0081]
In this embodiment, the CCD 4, the binarization circuit 6, the clock signal output circuit 14, the processing performed by the address generation circuit 16, the change point detection circuit 18 and the ratio detection circuit 20 at the timing, and the steps S100 and S121 performed by the control circuit 28. Corresponds to the two-dimensional code positioning process, steps S123 and S125 correspond to the size acquisition process, and step S140 corresponds to the decode process.
[0082]
[Others]
In the above embodiment, the positioning symbols 54, 76, 86 are double squares, and the frequency component ratio across the center is a graphic of black: white: black: white: black = 1: 1: 3: 1: 1. Although shown, it may be circular as shown in FIG. 12 (a), hexagonal as shown in FIG. 12 (b), or another regular polygon. In other words, any shape may be used as long as similar figures overlap in a concentric manner. Furthermore, as long as the frequency component ratio across the center is the same at all angles, as shown in FIG. Further, the positioning symbols 54, 76, and 86 are not represented by the frequency component ratio as described above, but may be other shapes as long as they are easily detected and distinguished in hardware or software. But it ’s okay.
[0083]
The number and interval of positioning symbols are determined as appropriate from the viewpoint of ease of symbol detection, the degree of reflection of distortion, and securing of a necessary amount of data.
In the above embodiment, the positioning symbols 54, 76, 86 are arranged at one of the four vertices of the two-dimensional codes 52, 74, 84, but in the two-dimensional codes 52, 74, 84. The arrangement at is arbitrary. If necessary, two positioning symbols may be provided in one two-dimensional code 52, 74, 84. For example, as shown in FIG. 13, two positioning symbols 93 and 94 may be arranged at adjacent vertices of the two-dimensional code 92, and size codes 97 and 98 may be provided in the data area 96. Since the size codes 97 and 98 are arranged on the apex side of the adjacent two-dimensional code 92 where the positioning symbols 93 and 94 do not exist with respect to the positioning symbols 93 and 94, respectively, the two-dimensional code 92 in this direction. The size is determined. From the types of the size codes 97 and 98, it can be seen that the vertical size in the figure is 21 cells. Note that the size in the horizontal direction in the figure is determined by the arrangement of the positioning symbols 93 and 94, so the arrangement of the size code is not necessary.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a two-dimensional code reading device according to an embodiment.
FIG. 2 is a schematic configuration explanatory diagram of an example of a two-dimensional code in the embodiment.
FIG. 3 is an explanatory diagram of a detailed configuration of an example of a two-dimensional code in the embodiment.
FIG. 4 is an explanatory diagram of light / dark detection when a positioning symbol is scanned in the embodiment.
FIG. 5 is an explanatory diagram of output signals from the CCD and the binarization circuit in the embodiment.
FIG. 6 is an explanatory diagram of types of size codes in the embodiment.
FIG. 7 is a schematic configuration explanatory diagram of a small example of a two-dimensional code in the embodiment.
FIG. 8 is a schematic configuration explanatory diagram of a large example of a two-dimensional code in the embodiment.
FIG. 9 is a flowchart of a two-dimensional code reading process in the embodiment.
FIG. 10 is an explanatory diagram of a processing procedure in the embodiment.
FIG. 11 is an explanatory diagram of a processing procedure in the embodiment.
FIG. 12 is an explanatory diagram illustrating an example of another shape of a positioning symbol.
FIG. 13 is an explanatory diagram of a schematic configuration of an example of another two-dimensional code.
FIG. 14 is an explanatory diagram of a conventional barcode and a two-dimensional code.
FIG. 15 is an explanatory diagram of a schematic configuration of a conventional two-dimensional code.
FIG. 16 is a diagram illustrating a detailed configuration of a conventional two-dimensional code.
[Explanation of symbols]
2 ... Two-dimensional code reader 4 ... CCD 6 ... Binary circuit
8 ... Image memory 14 ... Clock signal output circuit
16 ... Address generation circuit 18 ... Change point detection circuit 20 ... Ratio detection circuit
22 ... Address storage memory 28 ... Control circuit
52, 74, 84, 92 ... 2D code
54, 76, 86, 93, 94 ... positioning symbols
56, 78, 88, 96 ... data area
60, 62, 70, 72, 80, 82, 97, 98 ... size code

Claims (8)

A square- shaped two-dimensional code expressing information by a cell distribution pattern,
A square-shaped pattern which is arranged at a predetermined position in a two-dimensional code and can obtain a frequency component ratio of 1: 1: 3: 1: 1 when scanned in a plurality of different directions or in a plurality of different positions. A positioning symbol that identifies the position of the code;
It is arranged at a predetermined position with respect to the positioning symbol and along the two sides on the side where the data cell exists among the four sides of the positioning symbol, and the size of the two-dimensional code is represented by the cell distribution pattern. Two size codes,
And the size code is arranged by selecting a distribution pattern indicating the size of the two-dimensional code from a plurality of size codes having different distribution patterns for a predetermined number of cells. .   2. The two-dimensional code according to claim 1, wherein the size code represents a size of the two-dimensional code by a ratio to a size of a square positioning symbol.   3. The two-dimensional code according to claim 1, wherein the size code is arranged adjacent to the positioning symbol. The one positioning symbol is arranged at any one of four vertices of a two-dimensional code, and the size code represents a vertical and horizontal size of the two-dimensional code. The two-dimensional code according to any one of to 3 . Two of the size codes are respectively arranged on two sides on the side where the data cell exists among the four sides of the positioning symbol, and each size code is two-dimensional on each side of the arranged positioning symbol. 5. The two-dimensional code according to claim 4, which represents a size of the code. A method for reading a two-dimensional code according to any one of claims 1 to 5 ,
Obtaining an image of the two-dimensional code and performing a two-dimensional code positioning process for detecting the positioning symbol in the image;
Next, the size code is detected based on the detected positioning symbol, the distribution pattern of the cells forming the size code is detected, and the distribution pattern is decoded to represent the two-dimensional code represented by the size code Perform the size acquisition process to acquire the size of
Next, a two-dimensional code reading method comprising performing a decoding process of reading information of the two-dimensional code based on the acquired size of the two-dimensional code. The two-dimensional code positioning process obtains an image of the two-dimensional code, detects the position and shape of the positioning symbol in the image,
The size acquisition process detects the position of the size code based on the detected position and shape of the positioning symbol, detects a distribution pattern of cells forming the size code from the position, and detects the distribution pattern. To obtain the size of the two-dimensional code represented by the size code,
The decoding process detects the position of the data cell representing the information of the two-dimensional code based on the acquired size of the two-dimensional code and the shape of the positioning symbol, and obtains the information of the two-dimensional code from the position. The two-dimensional code reading method according to claim 6 , wherein the two-dimensional code is read. A method for reading a two-dimensional code according to claim 5 ,
Obtaining an image of the two-dimensional code and performing a two-dimensional code positioning process for detecting the position and shape of the positioning symbol in the image,
Next, based on the detected position and shape of the positioning symbol, the presence of two size codes is detected by inspecting predetermined positions on the four sides of the positioning symbol. Perform size acquisition processing to acquire the size of the two-dimensional code represented by
Next, for each of the two sides of the positioning symbol where the size code is detected, based on the size of the two-dimensional code acquired from the size code and the shape of the positioning symbol, A method for reading a two-dimensional code, comprising: performing a decoding process of detecting a position and reading information of the two-dimensional code from the data cell.

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