Two-dimensional code having rectangular region provided with specific patterns to specify cell positions and distinction from background

• US 8,424,775 B2
• Filed: 02/08/2012
• Issued: 04/23/2013
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Denso PS Corporation (DENSO Corporation)
• Original Assignee: Denso PS Corporation (DENSO Corporation)
• Inventors: Mizukoshi, Hiroaki, Tanaka, Masami, Ito, Yuichi, Kita, Hayato, Ushijima, Takao, Hara, Masahiro
• Primary Examiner(s): Labaze, Edwyn
• Application Number:
  US13/368,602
• Publication Number:
  US 20120132721A1
• Time in Patent Office: 440 Days
• Field of Search: 235/494, 235/454, 235/375, 235/462.09, 235/462.1
• US Class Current: 235/494
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 19/06075 the marking containing means for error correction

Abstract

A two-dimensional code having a rectangular region is provided. In the rectangular region, there are code blocks composed of a plurality of cells, a first specific pattern specifying the positions of the cells, and a second specific pattern separating the code blocks from a background of the code. The first specific pattern is located at a specified corner of the rectangular region. The second specific pattern is located along one or more of first borders along which the first specific pattern is located, the first borders being part of the borders of the rectangular region. The code blocks include error-correction code blocks, which are located along second borders which are different from a border of the borders along which the second specific pattern is located. The second borders are part of the borders. Compressed data code blocks are also arranged in the same way as the error-correction code blocks.

Claims

1. A two-dimensional code which is present on an object and formed to have a rectangular region delineated by a plurality of borders differentiated from a background on the object, comprising:

a plurality of code blocks including a plurality of data code blocks and a plurality of error-correction code blocks, the data code blocks being blocks in which data are coded, the error-correction code blocks being for correcting an error in the data code blocks, the data code blocks and the error-correction code blocks being composed of a plurality of cells which are aggregated;

a first specific pattern used to specify the positions of the cells; and

a second specific pattern used to distinguish the code blocks from the background on the object,

wherein the code blocks, the first specific pattern and the second specific pattern are arranged in the rectangular region,

the first specific pattern is located at a specified corner of the rectangular region,

the second specific pattern is located along one or more borders of two first borders along which the first specific pattern is located, the second specific pattern being adjacent to the first specific pattern, the first borders being part of the borders of the rectangular region,

the error-correction code blocks are located along second borders which are different from the one or more borders of the two first borders, the second borders being part of the borders of the rectangular region,

the respective cells of the error-correction code blocks are colored and the respective cells of data code blocks of which errors are corrected by the error-correction code blocks are colored, a combination of the colors for the cells of the error-correction code blocks being different from a combination of the colors for the cells of the data code blocks of which errors are corrected by the error-correction code blocks.

2. The two-dimensional code of claim 1, comprising a third specific pattern arranged along part of the second borders to distinguish the code blocks from the background,

wherein the error-correction code blocks and the third specific pattern are arranged along the second borders.

3. The two-dimensional code of claim 2, wherein the third specific pattern has a plurality of cells different in saturation, hue, or lightness from each other and arranged in a predetermined order.

4. The two-dimensional code of claim 2, wherein the third specific pattern and the second specific pattern are the same in shape.

5. The two-dimensional code of claim 1, wherein the rectangular region is a square region composed of a matrix whose one side is composed of odd-number L of cells so that a matrix size thereof is L×

L,

the first specific pattern has a contour which is a square composed of a matrix whose one side is composed of odd-number M of cells M (M<

L) so that a matrix size thereof is M×

M,

the second specific pattern is a linear pattern composed of even-number N of cells satisfying N=L−

M and being arranged linearly and

each of the code blocks is composed of a rectangular matrix having a matrix size of A×

B, whose one side is composed of even-number A of cells lined up and whose the other side is composed of even-number B of cells arranged linearly.

6. The two-dimensional code of claim 1, wherein the second specific pattern includes a plurality of cells which are different from each other in, at least, saturation, hue, or lightness.

7. The two-dimensional code of claim 1, wherein the rectangular region has a second corner positionally different from the first corner, and

the second specific pattern includes a first end pattern arranged at the second corner of the rectangular area.

8. The two-dimensional code of claim 7, wherein the second specific pattern is composed of the first end pattern.

9. The two-dimensional code of claim 7, wherein the first end pattern is a linear pattern composed of a plurality of cells which are continuously arranged linearly and which are the same in saturation, hue, or lightness.

10. The two-dimensional code of claim 7, wherein the first end pattern is a linear pattern composed of a plurality of cells which are arranged linearly in a predetermined order and which are different from each other in saturation, hue, or lightness.

11. The two-dimensional code of claim 7, wherein the first end pattern is an L-shaped pattern composed of a plurality of cells which are continuously arranged and which are the same in saturation, hue, or lightness.

12. The two-dimensional code of claim 7, wherein the first end pattern is an L-shaped pattern composed of a plurality of cells different in saturation, hue, or lightness from each other and arranged in a predetermined order.

13. The two-dimensional code of claim 7, wherein the first end pattern is composed of a single cell whose saturation, hue, or lightness is different from the background.

14. The two-dimensional code of claim 7, wherein the error-correction code blocks or a residual block is arranged around the first end pattern, the residual block storing therein a residual cell which is not allocated to the data code blocks storing data.

15. The two-dimensional code of claim 1, wherein

the code blocks include the error-correction code blocks for correcting an error, and

the error-correction code blocks are arranged adjacently to the second specific pattern arranged along the first borders.

16. The two-dimensional code of claim 1, wherein

the code blocks include the compressed data code blocks in which the compressed data are stored,

the second specific pattern arranged along the first borders has an inner side, and

the compressed data code blocks are arranged adjacently to the inner side of the second specific pattern.

17. The two-dimensional code of claim 1, comprising a second end pattern arranged at a corner of the rectangular region which is diagonally located to the first specific pattern in the rectangular region.

18. The two-dimensional code of claim 17, wherein the second end pattern is an L-shaped pattern composed of a plurality of cells which are continuously arranged and which are the same in saturation, hue, or lightness.

19. The two-dimensional code of claim 17, wherein the second end pattern is an L-shaped pattern composed of a plurality of cells different in saturation, hue, or lightness from each other and arranged in a predetermined order.

20. The two-dimensional code of claim 17, wherein the second end pattern includes a first cell having a given saturation, hue, or lightness and second cells which are different in saturation, hue, or lightness from the first cell, the second cells being arranged to enclose the first cell so that the second end pattern is rectangular.

21. The two-dimensional code of claim 17, wherein the rectangular region is a region in which a plurality of types of cells are arranged which are different in saturation, hue, or lightness from each other, and

the second end pattern is composed of a plurality of types of cells which are different in saturation, hue, or lightness from each other and which are arranged in a combination of given types of cells and serves as a reference region for making reference to a type of the rectangular region.

22. The two-dimensional code of claim 1, wherein the rectangular region is a region in which a plurality of types of cells are arranged which are different in saturation, hue, or lightness from each other, and

the second specific pattern is composed of a plurality of types of cells which are different in saturation, hue, or lightness from each other and which are arranged in a combination of given types of cells and serves as a reference region for making reference to a type of the rectangular region.

23. The two-dimensional code of claim 1, wherein the code blocks are expressed by the cells composed of X types and Y pieces of cells which are composed of composite data produced by adding, to data to be decoded having an information amount of N bits in binary number, error-detection data having an information amount of M bits in binary number, the composite data satisfying a relationship of X^Y-1<

2^N×

2^M<

X^Y.

24. The two-dimensional code of claim 1, comprising an end pattern arranged at a corner of the rectangular region which positionally differs from the specified corner of the rectangular region,

wherein the end pattern is previously given inherent length ratios corresponding to every size of the two-dimensional code, the inherent length ratios each providing the end pattern with a ratio between a longitudinal length thereof and a lateral length thereof.

25. The two-dimensional code of claim 24, wherein the inherent length ratio for each size of the two-dimensional code is predetermined such that a sum of C1 and C2 becomes larger with an increase in the inherent length ratio, wherein C1 and C2 are natural numbers both changeable every size of the two-dimensional code.

26. The two-dimensional code of claim 24, wherein the end pattern is composed of cells arranged in an L shape along borders of the corner of the rectangular region which positionally differs from the specified corner thereof.

27. The two-dimensional code of claim 1, wherein the code blocks include data code blocks in which encoded data are stored, the data being expressed by a plurality of digits of symbols composed of a plurality of types of symbols,

the encoded data satisfy a relationship of 2^F-1<

D^E<

2^F, wherein D denotes the number of types of the symbols and E and F are natural numbers, and

the data code blocks express a string of bits which are binary-converted every E digits that provides a bit conversion rate F/E with a given value.

28. The two-dimensional code of claim 27, wherein the given value is set to allow the bit conversion rate F/E to have the lowest value thereof.

29. The two-dimensional code of claim 27, wherein

the data code blocks express the string of bits which are binary-converted every E1 digits and residual digits of less than the E1 digits in the string of bits are binary-converted every E2 digits, wherein E1 denotes a value of the number of digits, E, obtained when the bit conversion rate F/E is the smallest and E2 denotes a value of the number of digits, E, obtained when the bit conversion rate F/E is next in smallness to the value E1 (0<

E2<

E1).

30. The two-dimensional code of claim 1, wherein the cells composing the code blocks include a plurality of cells which are the same kind as each other and arranged into a rectangular form to produce a large basic cell unit whose size is larger than the size of each of the cells, and the first specific pattern is composed of a combination of a plurality of the large basic cell units.

31. The two-dimensional code of claim 30, wherein the second specific pattern is composed of a combination of a plurality of cells each of which is the large basic cell unit.

32. The two-dimensional code of claim 30, wherein the larger basic cell unit and the cells composing the code blocks are analogous in shape to each other.

33. The two-dimensional code of claim 30, comprising a format information block indicating format information of the two-dimensional code and being composed of a plurality of cells each of which is the large basic cell unit.

34. The two-dimensional code of claim 33, wherein the format information block is arranged adjacently to, at least, one of the first specific pattern or the second specific pattern.

35. The two-dimensional code of claim 30, wherein each of the first specific pattern and the second specific pattern is composed of a combination of a plurality of cells each of which is the large basic cell unit, and

all of the respective large basic cell units composing the first specific pattern, the second specific pattern, and the format information block are the same in their sizes.

36. The two-dimensional code of claim 1, wherein the data blocks include a first data code block expressing a first data of a predetermined type and a second data code block expressing a second data which is different in type from the first data, and

the first data code block is arranged in a first area arranged in the code and the second data code block is arranged in a second area arranged in the code, the second area being positionally farther than the first area from the first specific pattern.

37. The two-dimensional code of claim 36, wherein each of the first data and the second data is given an error correction level, the error correction level of the first data being higher than that of the second data.

38. The two-dimensional code of claim 36, wherein the first data indicates format information and the second data indicates information other than the format information.

39. The two-dimensional code of claim 37, wherein the code blocks are subjected to a masking process performed using a prescribed one type of mask pattern.

40. A method of producing a two-dimensional code according to claim 1, including steps of:

acquiring object data to be encoded;

deciding cell configurations and arrangement positions of the first and second specific patterns so that the specific patterns are produced; and

deciding cell configurations and arrangement positions of the code blocks using the acquired object data so that the code blocks are produced, wherein the object data are divided into data having an information amount of binary N bits and each of the divided object data is added by error detection data having an information amount of binary M bits so that composite data are produced, and the cell configurations and the arrangement positions of each of the code blocks are decided such that the composite data are expressed by X types and Y pieces of cells that satisfy a relationship of X^Y-1<

2^N×

2^M<

X^Y.

41. A method of producing a two-dimensional code according to claim 1, the method including steps of:

acquiring object data to be encoded;

deciding cell configurations and arrangement positions of the first and second specific patterns so that the specific patterns are produced; and

deciding cell configurations and arrangement positions of the code blocks using the acquired object data so that the code blocks are produced,

calculating ratios of both bright cells and dark cells to be arranged in the rectangular region using not only the produced first and second specific patterns but also the produced code blocks;

determining whether or not the ratio of the dark cells in the rectangular region is larger than the ratio of the bright cells in the rectangular region based on the calculated ratios; and

mutually inverting the bright cells and the dark cells in the rectangular region when the ratio of the dark cells is larger than the ratio of the bright cells.

42. The method of claim 41, wherein the inverting step also mutually inverts bright cells and dark cells arranged in a marginal region adjacently surrounding the rectangular region.

43. A two-dimensional code which is present on an object and formed to have a rectangular region delineated by a plurality of borders differentiated from a background on the object, comprising:

a plurality of code blocks including a plurality of compressed data code blocks in each of which compressed data are stored, each of the code blocks being composed of a plurality of cells which are aggregated;

a first specific pattern used to specify the positions of the cells; and

a second specific pattern used to distinguish the code blocks from the background on the object,

wherein the code blocks, the first specific pattern and the second specific pattern are arranged in the rectangular region,

the first specific pattern is located at a specified corner of the rectangular region,

the second specific pattern is located along one or more borders of two first borders along which the first specific pattern is located, the second specific pattern being adjacent to the first specific pattern, the first borders being part of the borders of the rectangular region,

the compressed data code blocks are arranged along second borders which are different from the one or more borders of the two first borders, the second borders being part of the borders of the rectangular region,

the respective cells of the compressed data code blocks are colored and the respective cells of error-correction code blocks to correct the compressed data code blocks are colored, a combination of the colors of the cells of the compressed data code blocks being different from a combination of the colors of the cells of the error-correction code blocks.

44. The two-dimensional code of claim 43, comprising a third specific pattern arranged along part of the second borders to distinguish the code blocks from the background,

wherein the compressed data code blocks arranged along the second borders are arranged to positionally avoid the third specific pattern.