Dynamically variable machine readable binary code and method for reading and producing thereof

• US 5,473,151 A
• Filed: 06/23/1994
• Issued: 12/05/1995
• Est. Priority Date: 05/05/1988
• Status: Expired due to Term

• Current Assignee: Microscan Systems Inc (Omron Corporation)
• Original Assignee: International Data Matrix Incorporated
• Inventors: Priddy, Dennis G., Cymbalski, Robert S.
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): Le, Thien Minh
• Application Number:
  US08/264,855
• Time in Patent Office: 530 Days
• Field of Search: 235/436, 235/456, 235/494, 235/437, 235/432, 235/470, 380/55, 369/100, 371/43, 341/95
• US Class Current: 235/494
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 2019/06262 with target- or other orientation-indicating feature
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A machine readable binary code which is dynamically variable in size, format and density of information is provided. The binary code is formed as a matrix having a perimeter and data contained therein. The perimeter is provided with density indicia for indicating the density of data contained within the matrix. The perimeter is also provided with size indicia for indicating the size of the matrix. By utilizing the density indicia and size indicia, a scanning device is able to calculate the size and information density of the binary code.

Claims

1. A method for determining the size and density of a dynamically variable machine optically readable code having a perimeter and a plurality of data elements in a two dimensional array representing coded information within the perimeter, the code being made of optically distinguishable light areas and dark areas, the perimeter having a first side and a second side that intersect at a first corner, the first and second sides being formed of a solid line and having first and second lengths respectively, the code further including a density pattern corresponding to the density of the data elements contained in the code, comprising:

scanning a visual field containing a code with an optical scanning device and forming a bit map corresponding to the scanned visual field;

locating in the bit map the first and second sides of the code perimeter and the first corner;

determining the lengths of the first and second sides and calculating therefrom the code size; and

locating in the bit map the density pattern and determining the density of data elements in the code.

2. The method of claim 1 further comprising providing the density pattern as two lines of alternating light areas and dark areas wherein the number of light and dark areas in each line form a product corresponding to the density of data elements.

3. The method of claim 2 wherein forming the two lines further comprises forming the two lines as a third side and a fourth side of the perimeter, such that the third and fourth sides intersect at a second corner.

4. The method of claim 3 further comprising determining the orientation of the code relative to the visual field based on locating the first and second sides.

5. The method of claim 1 further comprising determining the orientation of the code relative to the visual field based on locating the first and second sides.

6. The method of any of claims 1, 2, or 3 further comprising determining the location of the plurality of data elements in the code based on determining the density pattern and the location and lengths of the first and second sides.

7. The method of claim 6 wherein determining the location of the data elements further comprises determining the angle between the first and second sides of the code perimeter and using the determined angle to compensate for any distortion of the code.

8. The method of claim 7 further comprising the step of reading data from the determined data element locations and decoding the coded information.

9. The method of claim 8 further comprising providing the code with a key pattern, wherein reading data further comprises reading the key pattern and using the key pattern to read data from the determined data element locations.

10. The method of claim 6 further comprising the step of reading data from the determined data element locations and decoding the coded information of the scanned code.

11. The method of claim 10 further comprising providing the code with a key pattern, wherein reading data further comprises reading the key pattern and using the key pattern to read data from the determined data element locations.

12. The method of claim 1 further comprising providing the coded information with said plurality of data elements arranged in redundant patterns of data elements having at least a three bit differential between said redundant patterns.

13. The method of claim 1 wherein the scanning step further comprises providing a light sensitive device, detecting radiation reflected from a visual field containing the code, forming a two-dimensional electronic representation of the visual field in response to the detected reflected radiation and forming the bit-map based on the two-dimensional electronic representation.

14. The method of claim 13 wherein the step of detecting radiation further comprises illuminating the visual field with radiation, wherein the detected reflected radiation is responsive to the illuminating radiation.

15. The method of claim 13 wherein the step of detecting radiation further comprises generating laser radiation, illuminating the visual field with said laser radiation, and detecting the radiation reflected in response to the laser radiation.

16. The method of claim 13 wherein the step of detecting radiation further comprises providing a light sensitive electronic array and capturing electronic data corresponding to a two-dimensional image of the visual field.

17. The method of claim 16 wherein the step of providing a light sensitive array further comprises providing light sensitive area array and a lens, focussing an image of the visual field on the area array, and capturing a two-dimensional electronic representation of the scanned visual field.

18. The method of claim 17 wherein providing a light sensitive area array and a lens further comprises providing an optical CCD camera.

19. The method of claim 16 wherein the step of providing a light sensitive array further comprises providing a linear array, and moving the linear array across the visual field and capturing a two-dimensional electronic representation of the visual field in response to said movement.

20. The method of claim 14 wherein the step of detecting radiation further comprises providing a light sensitive electronic array and capturing electronic data corresponding to a two-dimensional image of the visual field.

21. The method of claim 20 wherein the step of providing a light sensitive array further comprises providing light sensitive area array and a lens, focussing an image of the visual field on the area array, and capturing a two-dimensional electronic representation of the scanned visual field.

22. The method of claim 21 wherein providing a light sensitive area array and a lens further comprises providing an optical CCD camera.

23. The method of claims 20 wherein the step of providing a light sensitive array further comprises providing a linear array, and moving the linear array across the visual field and capturing a two-dimensional electronic representation of the visual field in response to said movement.

24. A method for producing a dynamically variable machine optically readable code having a perimeter and a plurality of data elements representing coded data within the perimeter, said code including a density pattern corresponding to the density of the data contained in the matrix, comprising:

providing data to be encoded in the code;

determining a first number of data elements required to represent the encoded provided data;

determining the size of the code to be formed to include said first number of data elements;

calculating a first perimeter side length and a second perimeter side length, the first and second lengths corresponding to the determined code size;

calculating the density of the determined first number of data elements in the determined code size and providing a first pattern of data elements representing the calculated density;

encoding the data to be encoded and forming the first number of data elements; and

producing a readable code as a two-dimensional array of said first number of data elements having a perimeter including the determined first and second perimeter sides as solid lines having the first and second perimeter lengths respectively and intersecting at a first corner, and the first data element pattern.

25. The method of claim 24 wherein providing the first data element pattern further comprises providing two lines of alternating light area and dark area data elements, such that the product of the numbers of light and dark areas in the two lines corresponds to the density of said first number of data elements.

26. The method of claim 25 wherein providing the two lines of alternating light area and dark area data elements further comprises providing said two lines with identical patterns of alternating light and dark areas, such that each line has a number of alternating light and dark areas that is the square root rounded up to the nearest whole number of the first number of data elements.

27. The method of claim 26 wherein providing the first data element pattern further comprises providing said two identical lines as a third side and a fourth side of the perimeter and intersecting at a second corner.

28. The method of claim 24 wherein the step of encoding the data further comprises encoding the data redundantly using multiple patterns of data elements.

29. The method of claim 24 wherein the step of encoding the data further comprises encoding the data with a key pattern for use in decoding the data, scrambling the data in a manner that the scrambled data read can be decoded by using the key pattern, and producing the readable code with said key pattern.

30. The method of claim 24 further comprising calculating the maximum number of possible variations necessary to display the data within the code and determining the minimum first number of data elements required to produce that number of variations.

31. The method of claim 30 further comprising forming the data elements within the perimeter of the code in a predetermined pattern.

32. The method of claim 30 further comprising forming the code with a distribution key containing information for decoding the predetermined pattern.

33. The method of claim 24 further comprising providing redundant data elements within the perimeter of the code about a root data element.

34. The method of claim 24 further comprising determining the size of the code perimeter by the user selecting the size of the code and adjusting the size of the data elements in response to the selected size and the data to be encoded.