Machine-readable color symbology and method and apparatus for reading same with standard readers such as laser scanners

• US 6,478,223 B1
• Filed: 01/12/2000
• Issued: 11/12/2002
• Est. Priority Date: 01/12/2000
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Ackley, H. Sprague
• Primary Examiner(s): Frech, Karl D.
• Assistant Examiner(s): Caputo, Lisa M.
• Application Number:
  US09/481,837
• Time in Patent Office: 1,035 Days
• Field of Search: 235/462.04, 235/462.02, 235/462.16, 235/462.01
• US Class Current: 235/462.04
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• 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 color symbology, such as a bar code symbology, employs three or more colors to encode elements of one or more integer-widths. A light source or an appropriate filter of a color matched to one color of the symbology produces peaks in a reflectance signal produced from a light sensor, which receives light reflected from the symbol. Another, unmatched, color in the symbology produces valleys in the reflectance profile. A third or intermediate color produces a reflectance signal in a middle portion of the reflectance profile. By identifying the peaks and valleys in the profile, the portions corresponding to the intermediate color, may be found by measuring distances between centers of the peaks and valleys in the reflectance profile. As a result, all elements, of all colors in the symbol, may be decoded using a simple data collection reader, such as a laser scanner, employing only a single color laser.

Claims

1. A method of decoding a bar code symbol representing encoded information, the bar code symbol including a plurality of bars, the method comprising:

receiving light reflected from the bar code symbol and producing an output signal therefrom that represents the bars comprising the bar code symbol, wherein the output signal includes valleys and peaks, wherein a first set of bars have at least a first color that produce valleys in the output symbol, a second set of bars have at least a second color and produce peaks in the output signal, and a third set of bars have at least a third color;

identifying the first and second sets of bars of the first and second colors based on valleys and peaks in the output signal having low and high reflectance, all respectively;

identifying the third set of bars having the third color based on an intermediate reflectance in the output signal;

measuring distances between the valleys and peaks of the identified bars of the first and second colors;

determining at least one representative narrow width of the bars of the first, second or third color based on the identified bars of the first and second colors and the measured distances;

determining a size and location of the plurality of bars based on at least the representative narrow width, and the measured distances; and

determining the information encoded as in the bar code symbol.

2. The method of claim 1 wherein the first, second and third colors correspond respectively to high, low and intermediate optical states, wherein measuring distances includes measuring center distances between the centers of the valleys and peaks of the identified bars of the first and second colors,

wherein determining a size and location includes:

creating a matrix that identifies a width of the bars having the third color, the matrix being created based on center distances and the representative narrow width; and

determining the size and location of the bars having the third color by comparing the measured center distances to the matrix.

3. The method of claim 1 wherein determining the size and location includes creating a matrix that identifies the size or number of bars having the third color and filling in the matrix with a determined number of the representative narrow widths.

4. The method of claim 1 wherein the first and second colors are complementary with respect to a color wheel, and wherein the symbol is selected from an industry standard symbology.

5. The method of claim 1 wherein the symbol includes at least one bar of a third size, and wherein identifying first and second sets of bars includes defining a plurality of thresholds for the output signal.

6. The method of claim 1 wherein receiving light includes scanning the symbol with a laser beam, and wherein a color of the laser beam is matched to the first color.

7. A method of decoding a machine-readable symbol representing encoded information, the symbol including a plurality of relatively spaced two-dimensional geometric elements, the method comprising:

receiving data representing light reflected from the elements of the symbol, wherein some elements have at least first and second colors, and wherein other elements have at least a third color;

identifying the elements of first and second colors as high and low reflectance elements in the received data;

identifying the elements of the third color as intermediate reflectance elements in the received data;

determining distances between the elements of the first and second colors in the received data; and

,

determining the information encoded in the symbol based on the determined distances between the elements of the first and second colors in the received data.

8. The method of claim 7 wherein the first, second and third colors correspond respectively to high, low and intermediate optical states, wherein determining distances includes measuring center distances between the centers of valleys and peaks in the received data, and wherein determining the information encoded in the symbol includes:

creating a matrix that identifies a number and size of the elements having the third color, the matrix being created based on center distances and a representative first size; and

determining a number and location of the elements having the third color by comparing the measured center distances to the matrix.

9. The method of claim 7 wherein determining the information encoded in the symbol includes creating a matrix that identifies a number and size of elements having the third color and filling in the matrix.

10. The method of claim 7 wherein the first and second colors are complementary with respect to a color wheel, and wherein the symbol is selected from an industry standard symbology.

11. The method of claim 7 wherein the symbol includes elements of at least first, second and third sizes, and wherein identifying the elements of first and second colors includes defining a plurality of thresholds for the received data, and wherein portions of the received data extending beyond the plurality of thresholds correspond to elements of the first and third sizes.

12. The method of claim 7 wherein receiving data includes scanning the symbol with a laser beam, and wherein a color of the laser beam is matched to the first color.

13. The method of claim 7 wherein the first and second colors represent polished and matte surfaces, respectively.

14. The method of claim 7 wherein the first and second colors represent differing portions formed in a holographic substrate.

15. The method of claim 7 wherein the first and second colors are light and dark states in a liquid crystal display.

16. The method of claim 7 wherein the symbol is relief formed in a surface, and wherein the first and second colors are flush and recessed portions of the surface.

17. The method of claim 7 wherein the symbol includes elements of at least first, second and third sizes, and wherein identifying the elements of first and second colors includes measuring widths of peaks and valleys in the received data at two thresholds.

18. An apparatus for decoding a machine-readable symbol representing encoded information, the machine-readable symbol including a plurality of relatively spaced shapes, the apparatus comprising:

a sensor that senses the machine-readable symbol and produces an output signal therefrom that represents shapes comprising the symbol, wherein some of the shapes have at least first and second colors, and other shapes have at least a third color;

a receiving and processing circuit that receives the output signal and identifies shapes of the first and second colors in the output signal as identified peaks and valleys in the output signal and shapes of the third color as intermediate portions of the output signal, measures distances between the identified peaks and valleys, and produces a signal indicative of the information encoded in the machine-readable symbol based on the shapes of the first and second color and a number and size of shapes of the third color.

19. The apparatus of claim 18, further comprising a hand-held housing at least partially enclosing the sensor and the receiving and processing circuit, and a trigger switch coupled to the processor, wherein the receiving and processing circuit includes a receiver and a processor, wherein the receiver receives the output signal as an analog waveform and produces a digital output signal therefrom, wherein the processor receives the digital output signal from the receiver, and wherein the receiver and the processor are monolithically integrated.

20. The apparatus of claim 18 wherein the first, second and third colors correspond respectively to high, low and intermediate optical states, wherein the receiving and processing circuit measures center distances between centers of valleys and peaks in the output signal, determines a representative first size, creates a matrix that identifies a size and number of the shapes having the third color, the matrix being created based on center distances and the representative first size, and determines a size and location of the shapes having the third color by comparing the measured center distances to the matrix.

21. The apparatus of claim 18 wherein the receiving and processing circuit creates a matrix that identifies shapes having the third color and fills in the matrix based on a determined first size.

22. The apparatus of claim 18 wherein the first and second colors are complementary with respect to a color wheel, and wherein the symbol is selected from an industry standard symbology.

23. The apparatus of claim 18 wherein the symbol includes shapes of at least first, second and third sizes, and wherein the receiving and processing circuit defines a plurality of thresholds for the output signal, and identifies portions of the received data extending beyond the plurality of thresholds as corresponding to shapes of the first and third sizes.

24. The apparatus of claim 18, further comprising a laser scanner that produces a laser beam, wherein a color of the laser beam is matched to the first color.

25. The apparatus of claim 18, further comprising at least one filter having a color that is matched to the first color.

26. The apparatus of claim 18 wherein the first and second colors of the symbols represent matte and smooth surfaces, respectively.

27. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, and wherein the low, intermediate and high optical states are differing portions formed in a holographic substrate.

28. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, wherein the low and high optical states are respective first and second colors complementary with respect to a color wheel, and wherein each symbol in the symbology is selected from a single industry standard symbology with the second size greater than the first size.

29. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, wherein the elements have only first and second sizes, and wherein the second size is greater than the first size.

30. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, and wherein at least one of the optical states is a color red.

31. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, wherein the low and high optical states are respective first and second primary colors, and wherein the intermediate optical state is a color adjacent to the first and second primary colors.

32. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, and wherein the low and high optical states are matched and unmatched, respectively, with respect to a color of a light source for automatically reading the symbology.

33. A machine-readable symbology having machine-readable symbols representing information encoded under an industry symbology standard, wherein each symbol in the machine-readable symbology includes a plurality of relatively spaced two-dimensional geometric elements, wherein the elements have at least first and second sizes, wherein the elements of the second size have at least low and high optical states, wherein the elements of the first size have an intermediate optical state, wherein the low and high optical states are matte and smooth surfaces, respectively, and wherein the intermediate optical state is a semi-smooth surface having an optical state between the matte and smooth surfaces.