Decoding method of two-dimensional code symbol mark.

TECHNICAL FIELD

The present invention relates to a decoding method of two-dimensional code symbol mark in the information processing field such as sales and production control.

BACKGROUND ART

At the present, the bar code method of displaying the code with black and white bars in various density, and reading with an optical code reader such as bar code reader and laser scanner in widely used in the distribution industry, production control and other fields.

The bar code is extremely small in the information transmission capacity because only black and white bars are displayed at narrow or wide intervals in one-dimensional direction. For example, the Chinese characters, Japanese hiragana and Arabic letters cannot be expressed.

Accordingly, the present inventor previously proposed two-dimensional code symbol marks in matrix, and the apparatus and method of reading them in the Japanese Laid-Open Patent No. Sho. 64-86289, Japanese Laid-Open Patent No. Sho. 64-76176, and PCT/JP90/00980.

The two-dimensional symbol mark is effective because an extremely large amount of information can be displayed and transmitted, and this two-dimensional code symbol mark is read by an image reader and the image is processed.

Such method of reading with image reader and processing the image is most ordinary means, but since the code symbol is read in very fine intervals, for example, 0.1 mm by the image reader and processed in analog process, the quantity of data to be read is very massive and the memory capacity increases extremely, and it takes time to read, and also decoding of the code symbol mark is time-consuming.

SUMMARY OF THE INVENTION

It is hence a primary object of the invention to read a two-dimensional code symbol mark in a small memory capacity, and decode at high speed.

It is other object of the invention to decode a two-dimensional symbol mark easily and promptly by reading the X-axis side indication line and Y-axis side indication line for specifying the information area of the two-dimensional code symbol mark, and division marks provided on them with a code reader to detect the X-axis side or Y-axis side, or the X-axis side and Y-axis side.

It is another object of the invention to decode and process by scanning the code reader at rough reading precision in spite of two-dimensional code symbol mark, thereby detecting the code symbol mark promptly.

It is another object of the invention to decode and process with line sensor or laser scanner of one-dimensional charge coupled device (CCD) in spite of two-dimensional code symbol mark.

It is a further different object of the invention to decode the code symbol mark promptly and accurately if the code symbol mark is distorted due to facsimile transmission, elongation or contraction of code paper, or see-though.

It is another different object of the invention to decode by easily and promptly reading the code mark within the information area specified by the X-axis side indication line and Y-axis side indication line of two-dimensional code symbol mark.

Other objects and advantages of the invention will be better under stood and appreciated from reading of the following description.

The invention presents, in order to solve the above problems in the light of the background described herein, a decoding method of two-dimensional code symbol mark and its improvement characterized by specifying an information area by and X-axis side indication line of the X-axis side and a Y-axis side indication line of the Y-axis side for determining the reading range of the two-dimensional code symbol mark, and reading the code mark of binary signal recorded in this information area, thereby decoding the code symbol mark, wherein the x-axis side indication line or/and Y-axis side indication line of the information area recording the code symbol mark, and the division marks recorded on such X-axis side indication line or/and Y-axis side indication line are first detected by the code reader, then the code marks of binary signals recorded in the information area are sequentially read by the code reader up to the end part of the Y-axis side indication line or/and X-axis side indication line at every interval of dividing the detected division mark by a specified integer value, and the code symbol mark recorded in the information area is decoded by decoding and processing the code mark recorded in each region formed in a square of which one side is the length of dividing the interval of the division marks read by the code reader or the division mark spacing by an integer value.

According to the invention, by detecting the X-axis side indication line, Y-axis side indication line, and their division marks by the code reader, in a range specified by the X-axis side indication line and Y-axis line indication lime by recording the two-dimensional code symbol mark may be easily discovered, so that decoding and processing may be executed.

Furthermore, by sequentially reading the recorded code mark at every interval specified by the division marks, the code marks recorded in the two-dimensional information area can be processed digitally, and can be read and processed by the code reader like the bar code, and therefore the memory capacity may be extremely decreased, and the decoding speed may be raised.

Moreover, by calculating the region of small division formed in a square of which one side is the length of dividing the interval of division marks or the division mark spacing by an integer value, and processing the information in every region of small division of the read code marks to decode the code symbol marks recorded in the information area, even the two-dimensional code symbol mark may be digitally processed, without image processing by image reader as required in the prior art, so as to be decoded and processed promptly.

Other embodiments, actions and effects thereof are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

<ul id="ul0001" list-style="none"><li>Fig. 1 is a partially omitted explanatory diagram for reading of code symbol mark by a code reader according to an embodiment of the invention,</li><li>Fig. 2 is a magnified view of a code symbol mark for explaining the reading of the same,</li><li>Fig. 3 is a flow chart for explaining reading and decoding process of the same,</li><li>Fig. 4 is an explanatory diagram of an embodiment of reading of the same,</li><li>Fig. 5 is a schematic diagram for explaining computer processing of the same,</li><li>Fig. 6 is an input explanatory diagram by a scanner in other embodiment of the same,</li><li>Fig. 7 is an explanatory diagram of reading of code symbol mark of the same, and</li><li>Fig. 8 is an explanatory diagram of reading of code symbol mark of a further different embodiment of the same.</li></ul>

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, some of the preferred embodiments of the invention are described in detail below. Fig.1 to Fig.5 relates to an embodiment of the invention. In a data sheet 1 of specified dimensions, a matrix two-dimensional code symbol mark 2 is recorded as shown in Fig. 1, and this code symbol mark 2 is read by a code reader 3 of a CCD sensor of image pickup device for one-dimensional use.

The code symbol mark 2 comprises, as shown in Fig.1 and Fig. 2, an X-axis side indication line 4 for determining the X-axis side, a Y-axis side indication line 5 for determining the Y-axis side, and a corner mark 6 of an asymmetrical shape at a diagonal position of their intersection, and division marks 7 are provided on the X-axis side indication line 4 and Y-axis side indication line 5 so as to segment these lines into a plurality.

The division marks 7 are, as shown in Fig.1 and Fig. 2, to segment the X-axis side indication line 4 and Y-axis side indication line 5 at specific intervals, and also the width and length of the division marks 7 are equalized with the above interval so as to record the code symbol mark 2 at highest possible density.

In this way, by properly recording code marks 9 of binary symbol at proper positions (Xi, Yi) (only one position is shown in Fig.1 for the ease of understanding) in the information area 8 enclosed by the X-axis side indication line 4, Y-axis side indication line 5 and corner mark 6, the specified code symbol mark 2 is expressed.

For example, in the region enclosed by four or five division marks 7 corresponding to the intersection side of the X-axis side indication line 4 and Y-axis side indication line 5 of the information area 8, the principal information such as production information, accounting information and management information is recorded, and on the circumference side the auxiliary information such as nation information and cipher information is recorded, so that a large quantity of information may be expressed and transmitted.

In the method of reading the code symbol mark 2 by the code reader 3 of one-dimensional CCD sensor, for example as shown in Fig. 3 and Fig. 4(A), first the code reader 3 is moved at rough reading precision in the direction of the X-axis at every 3 to 10 mm, or preferably 5 to 10 mm to detect the Y-axis side indication line 5, X-axis side indication line 4 and corner mark 6, and the positions of the Y-axis side indication line 5, X-axis side indication line 4 and corner mark 6 are entered in a microcomputer 10 through and input interface 11 as shown in Fig. 5. The Y-axis side indication line 5 and X-axis side indication line 4 may be detected by sensing a continuous bar of a specific length. Thus, since the code reader 3 is moved roughly, the position of the code symbol mark 2 and the information region may be detected in a short time.

From a region slightly larger than the information area 8 of the code symbol mark 2 detected above, the Y-axis side indication line 5, the position and width of the division marks 7, the number of division marks 7 and their interval are detected in relation with the relative length with the Y-axis side indication line 5 as shown in Fig.3 and Fig. 4(B) by a precise reading pitch of 0.1 to 0.5 mm (the pitch to be read, corresponding to the size of the code symbol mark) again by the code reader 3 as shown in Fig. 4(B), and are fed into the microcomputer 10. The division marks 7 are recognized by detecting a continuous array at specific intervals on the Y-axis side indication line 5. Meanwhile, the interval of division marks 7, supposing to be equal, may he calculated from the length of the Y-axis side indication line 5 and number and width of the division marks 7.

In the code symbol mark 2, as shown in Fig. 1 and Fig. 2, since line 4 and Y-axis side indication line 5, the code reader 3 may be scanned from either the X-axis side or the Y-axis side so as to read, and by the presence or absence of detection of division marks 7, the code symbol mark 2 may be promptly distinguished, so as to decide whether or not to decode easily.

In this way, when the division marks 7 at the Y-axis side indication line 5 side are detected, on the basis of this Y-axis detection, as shown in Fig. 4(B), the detected data is rotated 90 degrees, and the position of the division marks 7 of the X-axis side indication line 4 side is calculated.

After decoding, at every interval of the division marks 7 calculated in the X-axis direction according to Fig. 3, the cord mark 9 at the position recorded in the information area 8 (Xi, Yi) as shown in Fig. 4(C) is sequentially read by the code reader 3, and is fed into a memory unit 12 of the RAM of the computer 10. After the end of the X-axis side indication line 4 or the end of the corner mark 6, when passing over the predetermined range, reading is terminated.

Since the code mark 9 is read at every interval of the division marks 7 in this way, digital, not analog, reading is processed same as in bar code. It is particularly preferred to read at the middle point of the division marks 7 and every middle point between the division marks 7 as shown in Fig. 4(C) in order to prevent errors.

When reading by the code reader 3 is over, according to the direction of the asymmetric corner mark 6, the code mark 9 in the region (Xi, Yi) of a small division formed in a square of which one side is the interval of the division marks 7 from the detected division mark 7 side is analyzed by programmed dimensional analytical process or other method, and the code symbol mark 2 recorded in the information area 8 specified by the X-axis side indication line 4 and Y-axis side indication line 5 is decoded, and as required it si delivered to an external display means 14 such as printer through an output interface 13 as shown in Fig. 5.

Since the corner mark is slightly slender and asymmetric as shown in Fig. 1 and Fig. 2, even if the X-axis side indication line and Y-axis side indication line, or their division marks are symmetrical, the code symbol mark recorded in the information area may be decoded accurately. Furthermore, by detecting the corner mark, the code symbol mark may be accurately decoded even if the information area is detected in a rhombic shape by scanning the code symbol by seeing through with the code reader. Therefore, even in the two-dimensional code symbol mark, it can be decoded and processed one-dimensionally and digitally on the basis of the division marks, and analog image processing as in the conventional two-dimensional image processing is not required, and therefore the memory capacity is extremely small, so that it is possible to read at high speed and decode at high speed.

Other Embodiment

In other embodiment, as shown in Fig. 6, the code symbol mark 2 is read by the code reader 3 of one-dimensional laser scanner for detecting the reflected light of laser beam by the photo detector by revolving and oscillating a polygon mirror 3A.

In this embodiment, the laser beam is scanned by oscillating the polygon mirror 3A in the Y-axis direction as shown in the diagram, and the Y-axis side indication line 5 and division marks 7 are detected, and also by oscillating and scanning in the X-axis direction (if necessary, possible to scan in both Y-axis direction and X-axis direction), the X-axis side indication line 4 and its division marks 7 are detected, and the division marks 7 and the code mark 9 recorded in specified position (Xi, Yi) of the information area 8 in every interval of division marks 7 are sequentially read in the same manner as above, thereby analyzing as shown herein.

In this embodiment, by detecting the individual division marks of the X-axis side indication line and small division in a square of which one side is the interval of division marks may be securely and accurately determined, and decoding errors may be prevented.

In the embodiment, too, if the code symbol mark 2 is elongated or contracted due to facsimile transmission or the like, by detecting the division marks 7, the information region may be accurately detected, and decoded.

Another Embodiment

Fig. 8 shows another embodiment of the invention. This embodiment relates to a decoding method of code symbol mark 2 corresponding to a case in which the information area 8 formed by the X-axis side indication line 4 and Y-axis side indication line 5 is deformed vertically and laterally (slightly exaggerated in the diagram).

In this embodiment, as mentioned above, the code symbol mark 2 is read by the code reader 3 and is fed into the microcomputer 10, while the start point O and end point B of the Y-axis side indication line 5, and the start point O and end point A of the X-axis side indication line 4, and also the end point C of the corner mark 6 are detected.

Consequently, by the microcomputer 10, the Y-axis side indication line (4, O-B) corresponding to the X-axis side indication line (4, O-A), the crossing angles ϑo, ϑxn of A-C line , and the crossing angle ϑyn of B-C line to the Y-axis side indication line (4, O-B) are calculated in the following equations by program processing.<maths id="math0001"><img file="EP0564708A2_D0001.tif" /></maths> where Nx is the number of division marks on the X-axis side indication line 4 for linear interpolation, and Ny is the number of division marks on the Y-axis side indication line 5 for linear interpolation.

By calculating the slant angle in the linear interpolation method of equations (1), (2), the Y-axis side division line 14, and X-axis side division line 15 starting from the i-th division mark 7 on the X-axis side indication line 4 and the i-th division mark 7 on the Y-axis side indication line 5 can be individually calculated.

In sequence, by processing the recorded information of the code mark 9 in each region of small division of square formed by these intersections, the code symbol mark 2 of the information area 8 is decoded and processed.

In the embodiment, if the information area specified by the X-axis side indication line and Y-axis side indication line is deformed in a rhombic shape or the like by facsimile transmission, paper elongation or contraction, see-through reading or the like, the region of each small division of information area may be accurately restored, and recording of code mark can be detected, and the two-dimensional code symbol mark may be decoded and processed.

In this embodiment, too, by the linear interpolation method according to the above principle, the division line calculating the slant angle passing through each end part of division mark is deduced, and recording of code mark in the region enclosed by the crossing points of these division lines may be processed same as in the foregoing embodiment.

In the explanation herein, for the ease of understanding, the reading method of only one code symbol mark is explained, but it is obvious that a plurality or a multiplicity may be similarly read and processed.

Besides, in these embodiments, for the sake of simplicity, the code mark is detected at every interval of the division marks (the interval of division marks divided by an integer value of 1), but even in the case of code symbol mark recording the code marks by dividing the interval of division marks into a plurality by an integer value of 2 or 4, the code mark at position (Xij, Ykl) may be similarly decoded and processed by programmed dimensional processing method, by reading and processing at every interval of the division marks into a plurality by the integer value by means of the code reader.

In the embodiment, the division marks are as wide as the interval of division marks so as to record the code marks as the densely as possible, but if the division marks are narrow, the intermediate point of the division mark may be regarded as the interval of the division marks, so that it is possible to realize similarly according to the spirit of the invention.

In the foregoing embodiments, the information region of small division of code symbol mark is calculated within the square enclosed by intersection of division lines according to the division marks of the X-axis side indication line and Y-axis side indication line, but it is also possible to calculate within the square of a specified range of which the center is each intersection of division lines one side is the length of the interval of division marks or dividing this interval by an integer value.

The above embodiments relate to optical detecting methods, but it is also possible to decode and process by writing the two-dimensional code symbol mark by using a magnetic material, and reading by a code reader making use of the magnetic head of a floppy disk drive of a computer, and hence it may be applied in IC card, telephone card and others economically.

Incidentally, instead of the one-dimensional code reader explained herein, a two-dimensional code reader may be similarly applied to decode and process the code symbol mark.

Thus, in the invention, the two-dimensional code symbol mark may be decoded and processed by easily reading the code marks in the information area according to the division marks of the X-axis side indication line and Y-axis side indication line by means of the code reader, and therefore the recording capacity may be extremely saved, and it is possible to process at high speed.