Method and apparatus for encoding and decoding bar codes with primary and secondary information and method of using such bar codes

• US 20030121980A1
• Filed: 02/06/2003
• Published: 07/03/2003
• Est. Priority Date: 01/03/1995
• Status: Active Grant

• Current Assignee: Jerome H. Lemelson, John H. Hiett
• Original Assignee: Jerome H. Lemelson, John H. Hiett
• Inventors: Lemelson, Jerome H., Hiett, John H.
• Granted Patent: US 6,991,164 B2
• Time in Patent Office: Days
• US Class Current: 235/462.08
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/06056 the marking comprising a further embedded marking, e.g. a 1D bar code with the black bars containing a smaller sized coding
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1434 Barcodes with supplemental or add-on codes

Abstract

A bar code (10) has primary information (46, 48, 50, 51) encoded in one direction (e.g., horizontally) and secondary information (13,21,36) encoded in another direction (e.g., vertically) in single (11) or multiple tracks (35) in selected ones of the vertical bars (11) of a bar code (10). Using a non-linear, variable amplitude scanner, all of the primary bars are scanned in the one direction to obtain all of the primary information and all of those vertical bars having secondary information are scanned in the other direction to obtain all of the secondary information. The one direction which is perpendicular to the vertical primary bars (11), is determined by first rotating the scan path axis (86,87) until both start (46) and end (48) code bars are read thereby placing the scan path entirely within the total bar code, and, then, further rotating the scan path (88,89) to determine the direction of the minimum crossing width (Lsc 80) of the total bar code (10). Secondary information is scanned in planes orthogonal to the one direction after those vertical bars (11) having such information are first identified and selected. In a preferred embodiment, the decoded secondary information may be used to control selected station process operations for selected products in a continuous manufacturing assembly line.

Claims

1. A method of reading a bar code having an area with primary and secondary information encoded therein comprising the steps of

scanning the area in one direction to decode the primary information, and

scanning the area in another direction to decode the secondary information.

2. The method of claim 1 wherein the area includes a plurality of spaced apart primary bars or rings and

the step of scanning the primary area in the one direction further comprises scanning across the bars or the rings, and

the step of scanning the primary area in the other direction further comprises scanning parallel to the bars or around the rings.

3. The method of claim 2 wherein

the step of scanning in the one direction further comprises scanning across parallel bars or concentric rings, and

the step of scanning in the other direction includes scanning parallel to the parallel bars or around the concentric rings.

4. The method of claim 1 wherein the area includes a plurality of spaced apart primary bars and the step of scanning the primary bars in the one direction further comprises the steps of:

locating a direction perpendicular to the primary bars,

scanning the primary bars in the perpendicular direction, and

interpreting the decoded primary information obtained.

5. The method of claim 4 wherein the step of locating a direction perpendicular to the primary bars further comprises the step of:

scanning the primary bars with a scan beam in a scan path in a plane of the area which path is rotated about one or more axes sequentially as necessary until the path crosses the entire bar code in a minimum crossing distance.

6. The method of claim 4 wherein the step of locating a direction perpendicular to the primary bars further comprises the steps of:

scanning the primary bars with a scan beam in a scan path in a plane of the bars while the path is rotated about one axis until the path crosses a start or stop code of the bar code thereby identifying a crossing length of the bar code,

shifting the axis of rotation to a point within the bar code substantially at the center of the crossing length of the bar code, and

continuing to rotate the scan path until both a start and stop code of the bar code are crossed in a minimum crossing length.

7. The method of claim 4 wherein the step of locating a direction perpendicular to the primary bars further comprises the steps of:

scanning the primary bars with a scan beam in a scan path at an angle to a transverse axis common to all of the bars,

positioning the scan beam path across an entire crossing length of the bar code, and

minimizing the entire crossing length of the scan beam path across the bar code.

8. The method of claim 7 wherein the step of positioning the scan beam path across an entire crossing length of the bar code further comprises the steps of:

rotating the scan beam path about a first axis until at least a portion of the bar code is crossed by the path,

measuring the length of the path portion crossing the bar code,

substantially re-positioning the axis of rotation of the path at the center of the path portion crossing the bar code, and

rotating the scan beam path about the re-positioned axis until the scan beam path crosses the entire bar code.

9. The method of claim 8 wherein the step of positioning the scan beam path across an entire crossing length of the bar code further comprises the step of

sequentially rotating the scan beam path about a plurality of axes as necessary until the scan path is inside of the entire bar code in a minimum crossing distance.

10. The method of claim 7 wherein the step of positioning the scan beam further comprises the step of:

changing the angle at which the primary bars are scanned in a direction wherein the crossing length decreases.

11. The method of claim 7 wherein the step of minimizing the entire crossing length further comprises the step of:

substantially centering a scan rotation axis of the scan path at a center of a last measured crossing length of the bar code,

changing the angle at which the primary bars are scanned in a direction of decreasing crossing length, and

repeating the centering and changing steps until the crossing length is a minimum length across the entire bar code.

12. The method of claim 4 wherein the step of locating a direction perpendicular to the primary bars further comprises the step of using an image processing system to find the perpendicular direction.

13. The method of claim 4 wherein the step of locating a direction perpendicular to the primary bars further comprises the step of:

using multiple beams that find the perpendicular direction when the multiple beams simultaneously cross a primary bar.

14. The method of claim 1 wherein the area is a plurality of spaced apart bars and the step of scanning the bars in the other direction to decode the secondary information further comprises the steps of:

determining a direction perpendicular to the bars,

identifying each bar with secondary information encoded therein,

scanning selected ones of the bars in the other direction orthogonal to the one direction.

15. The method of claim 14 wherein the determining, identifying and orthogonal scanning steps are continuously repeated until all of the selected secondary information is decoded.

16. The method of claim 14 wherein the secondary information is encoded in tracks in the area at an angle to the one direction further comprising the steps of:

identifying each track of secondary information,

selecting an identified track to be scanned, and

scanning the selected track to decode the secondary information.

17. The method of claim 16 wherein the step of scanning the selected track further comprises the steps of:

first positioning the scan beam at the selected track.

18. The method of claim 17 wherein the steps of identifying, selecting, positioning and scanning are continuously repeated until all of the selected secondary information is decoded.

19. The method of claim 1 wherein the area is a plurality of spaced apart bars and the step of scanning the bars in the other direction further comprises the steps of:

positioning a scan beam path parallel to the other direction of encoded secondary information,

moving the scan beam in the other direction to one end of the area,

rotating the scan beam to a direction opposite the other direction,

scanning the area of encoded secondary information in the opposite direction along an entire length of a bar, and

interpreting the secondary information obtained.

20. The method of claim 1 wherein the step of scanning the area in one direction further comprises the step of:

filtering secondary information which interferes with scanning the primary information.

21. The method of claim 20 wherein the step of filtering further comprises the step of:

scanning the area with a non-linear scan beam to obtain the primary information.

22. The method of claim 21 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a square wave scan beam to obtain the primary information.

23. The method of claim 21 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a sinusoidal wave scan beam to obtain the primary information.

24. The method of claim 21 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a triangular wave scan beam to obtain the primary information.

25. The method of claim 21 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a random pattern scan beam to obtain the primary information.

26. The method of claim 21 wherein the area is a plurality of spaced apart bars and wherein the step of scanning the area with a non-linear scan beam further comprises the step of:

providing a non-linear scan beam that has

a minimum scan cycle width that is a fraction of a smallest width of each of the primary bars and a smallest width of each of a number of spaces between the primary bars, and

a height that is at least greater than a maximum dimension of spaces used for defining the secondary information and less than a height of the primary bars.

27. The method of claim 20 wherein the area is a plurality of spaced apart bars and wherein the step of filtering further comprises the step of:

detecting a proper width of a bar by providing a detectable dark region border on each side of the encoded secondary information in the space where said information is encoded such that each border is generally perpendicular to the one direction for scanning the bars for obtaining the primary information and wherein each border has a width less than the smallest width of all of the primary bars.

28. The method of claim 1 wherein the step of scanning the area in the other direction to obtain the secondary information comprises the step of:

scanning the area with a non-linear scan beam to obtain the secondary information.

29. The method of claim 28 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a square wave scan beam to obtain the secondary information.

30. The method of claim 28 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a sinusoidal wave scan beam to obtain the secondary information.

31. The method of claim 28 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a triangular wave scan beam to obtain the secondary information.

32. The method of claim 28 wherein the step of scanning the area with a nonlinear scan beam further comprises the step of:

scanning the area with a random pattern scan beam to obtain the secondary information.

33. The method of claim 28 wherein the area is a plurality of spaced apart bars and the step of scanning the area with a non-linear scan beam further comprises the step of:

providing a non-linear scan beam having

a scan cycle width that is less than the height of the bar, and

a maximum height that is centered on the bar and that is approximately equal and slightly smaller than the width of the bar being scanned.

34. A system for reading a bar code having areas with primary and secondary information encoded therein comprising:

a computer system for controlling the reading of the bar code,

a horizontal driver and a vertical driver coupled to the computer system,

a horizontal actuator coupled to the horizontal driver and the computer system for controlling horizontal directional scanning of the bar code,

a vertical actuator coupled to the vertical driver and the computer system for controlling vertical directional scanning of the bar code,

a laser for producing a scanning beam,

optics coupled to the horizontal actuator and the vertical actuator for controlling the beam of the laser onto the bar code in a predetermined scanning pattern to receive reflected light from the bar code representative of the primary information encoded therein in one direction and the secondary information encoded therein in another direction,

a photodetector coupled to the optics for producing an analog voltage output corresponding to the intensity of the measured reflected light received by the photodetector via the optics, and

an analog to digital converter coupled to the photodetector and the computer system for converting the analog voltage output to a digital signal which is coupled to the computer system for interpretation.

35. A method of using a bar code having areas with primary information and secondary information encoded therein to control work to be performed on a workpiece comprising the steps of:

applying the bar code to the workpiece

scanning the bar code and decoding the primary information in the bar code to identify the workpiece,

determining the areas of the bar code with secondary information describing the work to be performed on the workpiece,

scanning selected ones of those areas of the bar code having the desired secondary information,

commanding selected ones of a plurality of work stations to perform work on the workpiece according to the decoded secondary information, and

performing the commanded work on the workpiece at the assigned stations.