Optoelectronic device, process and article for acquiring machine-readable symbols, such as bar codes

• US 7,451,933 B2
• Filed: 04/19/2005
• Issued: 11/18/2008
• Est. Priority Date: 04/19/2005
• Status: Active Grant

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Ackley, H. Sprague, Massieu, Jean-Louis
• Primary Examiner(s): Walsh; Daniel I
• Application Number:
  US11/110,571
• Publication Number:
  US 20060231629A1
• Time in Patent Office: 1,309 Days
• Field of Search: 235/462.12, 235/462.25, 235/462.36, 235/462.38, 235/462.39
• US Class Current: 235/462.39
• CPC Class Codes: G06K 7/10554 Moving beam scanning
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/1465 using several successive scans of the optical code

Abstract

A device and a process for acquiring symbols by interleaving data samples in a plurality of data sets gathered during sampling of returns from a plurality of scanning passes. In one embodiment, the sampling frequency is proportional to the scanning frequency by a quotient of twice the number of samples in a representation and an integer such that the quotient is an irreducible fraction.

Claims

1. A method of acquiring a machine-readable symbol using an optoelectronic device, the method comprising:

scanning the machine-readable symbol with a plurality of scanning passes occurring at a scanning frequency;

receiving reflected scans corresponding to the plurality of scanning passes;

converting the reflected scans to an electrical signal;

sampling the electrical signal at a sampling frequency thereby producing data samples associated with corresponding scanning passes;

interleaving data samples associated with at least two of the scanning passes to produce a representation in a memory, wherein the sampling frequency is proportional to the scanning frequency by a quotient of twice a number of samples in the representation and an integer such that the quotient is an irreducible fraction; and

decoding the representation.

2. The method of claim 1 wherein the representation in the memory is a representation in a time domain.

3. The method of claim 1 wherein the representation in the memory is a representation in a spatial domain.

4. The method of claim 1 wherein interleaving data samples comprises:

storing a first data sample in the memory at an address;

incrementing the address; and

storing a second data sample in the memory at the incremented address.

5. The method of claim 4 wherein the memory address is incremented by one.

6. The method of claim 4 wherein the memory address is incremented by the integer.

7. The method of claim 1 wherein the scanning the machine-readable symbol with a plurality of scanning passes occurring at a scanning frequency comprises:

driving a beam deflection system at the scanning frequency.

8. The method of claim 7 wherein the beam deflection system comprises a silicon micro-mirror suspension system.

9. The method of claim 1 wherein the machine-readable symbol is a bar code symbol.

10. The method of claim 1 wherein the plurality of scanning passes is a plurality of backward scanning passes and the representation is a first representation associated with the plurality of backward scanning passes, the method further comprising:

scanning the machine-readable symbol with a plurality of forward scanning passes occurring at the scanning frequency, wherein receiving reflected scans corresponding to the plurality of scanning passes comprises receiving reflected scans corresponding to the plurality of backward scanning passes and to the plurality of forward scanning passes; and

interleaving data samples associated with at least two of the forward scanning passes to produce a second representation in the memory.

11. The method of claim 1, further comprising:

scanning the machine-readable symbol with additional scanning passes occurring at the scanning frequency;

receiving additional reflected scans corresponding to the additional scanning passes;

converting the additional reflected scans corresponding to the additional scanning passes to an additional electrical signal;

sampling the additional electrical signal at the sampling frequency thereby producing additional data samples associated with corresponding additional scanning passes; and

interleaving data samples associated with at least two of the additional scanning passes to refresh the representation in the memory.

12. A method of acquiring a machine-readable symbol using an optoelectronic device, the method comprising:

scanning the machine-readable symbol with a plurality of scanning passes occurring at a scanning frequency;

receiving reflected scans corresponding to the plurality of scanning passes;

converting the reflected scans to an electrical signal;

sampling the electrical signal at a sampling frequency thereby producing data samples associated with corresponding scanning passes; and

interleaving data samples associated with at least two of the scanning passes to produce a representation in a memory, wherein the representation in the memory comprises a number of data samples and the sampling frequency is proportional to the scanning frequency by a quotient of a product of the number of data samples in the representation and a natural number divided by an integer, such that the quotient is a irreducible fraction.

13. The method of claim 12 wherein the representation in the memory is a representation in a time domain.

14. The method of claim 12 wherein the representation in the memory is a representation in a spatial domain.

15. The method of claim 12 wherein interleaving data samples comprises:

storing a first data sample in the memory at an address;

incrementing the address; and

storing a second data sample in the memory at the incremented address.

16. The method of claim 15 wherein the memory address is incremented by one.

17. The method of claim 12, wherein the natural number is two.

18. The method of claim 12 wherein the natural number is one.

19. The method of claim 12 wherein the scanning the machine-readable symbol with a plurality of scanning passes occurring at a scanning frequency comprises:

driving a beam deflection system at the scanning frequency.

20. The method of claim 19 wherein the beam deflection system comprises a silicon micro-mirror suspension system.

21. The method of claim 12 wherein the machine-readable symbol is a bar code symbol.

22. The method of claim 12 wherein the scanning frequency exceeds 200 Hz.

23. The method of claim 12 wherein the plurality of scanning passes is a plurality of backward scanning passes and the representation is a first representation associated with the plurality of backward scanning passes, the method further comprising:

scanning the machine-readable symbol with a plurality of forward scanning passes occurring at the scanning frequency, wherein receiving reflected scans corresponding to the plurality of scanning passes comprises receiving reflected scans corresponding to the plurality of backward scanning passes and to the plurality of forward scanning passes; and

interleaving data samples associated with at least two of the forward scanning passes to produce a second representation in the memory.

24. The method of claim 12, further comprising:

scanning the machine-readable symbol with additional scanning passes occurring at the scanning frequency;

receiving additional reflected scans corresponding to the additional scanning passes;

converting the additional reflected scans corresponding to the additional scanning passes to an additional electrical signal;

sampling the additional electrical signal at the sampling frequency thereby producing additional data samples associated with corresponding additional scanning passes; and

interleaving data samples associated with at least two of the additional scanning passes to refresh the representation in the memory.

25. An optoelectronic device for acquiring a machine-readable symbol, comprising:

a beam subsystem configured to generate scanning beam passes at a scanning frequency;

a reception subsystem configured to convert light reflected from the scanning beam passes to an electrical signal;

a sampler configured to sample the electrical signal at a sampling frequency, thereby producing sets of samples associated with corresponding scanning beam passes; and

a memory configured to interleave samples from at least two of the sets of samples, thereby producing a representation in the memory, wherein the sampling frequency is proportional to the scanning frequency by a quotient of a product of data samples in the representation in the memory and a natural number divided by an integer, such that the quotient is an irreducible fraction.

26. The device of claim 25 wherein the beam subsystem comprises a rotating polygonal mirror.

27. The device of claim 25 wherein the beam subsystem comprises a silicon micro-mirror suspension system configured to oscillate at the scanning frequency.

28. The device of claim 25 wherein the memory is configured to produce a time-domain representation.

29. The device of claim 25 wherein the memory is configured to produce a spatial-domain representation.

30. The device of claim 25 wherein the memory is configured to:

store a data sample at an address;

increment the address; and

store a subsequent data sample at the incremented address.

31. The device of claim 30 wherein the memory is configured to increment the address by one.

32. The device of claim 30 wherein the memory is configured to increment the address by the integer.

33. The device of claim 25 wherein the natural number is one.

34. The device of claim 25 wherein the natural number is two.

35. The device of claim 25 wherein the scanning frequency exceeds 200 Hz.

36. The device of claim 25 wherein the scanning beam passes comprise backward and forward scanning beam passes and the memory is configured to interleave samples from sets of samples associated with at least two backward scanning beam passes and from sets of samples associated with at least two forward scanning beam passes, thereby producing two representations in the memory.

37. The device of claim 25 wherein the memory is configured to interleave samples from sets of samples associated with additional scanning beam passes, thereby refreshing the representation in the memory.

38. A device for acquiring a machine-readable symbol, comprising:

means for generating a scanning beam at a scanning frequency;

means for converting light reflected from the scanning beam to an electrical signal;

means for sampling the electrical signal at a sampling frequency; and

means for interleaving samples of the electrical signal associated with a plurality of scanning beam passes, thereby producing a representation, wherein the means for interleaving samples comprises a memory having a modulo and the sampling frequency is proportional to the scanning frequency by a quotient of a product of the modulo and a natural number divided by an integer such that the quotient is an irreducible fraction.

39. The device of claim 38 wherein the means for generating a scanning beam comprises a silicon micro-mirror suspension system.

40. The device of claim 38 wherein the natural number is one.

41. The device of claim 38 wherein the machine-readable symbol is a bar code symbol.

42. A computer readable memory medium loadable in a memory of a processor of a system, comprising software code portions for causing the system to:

scan a machine-readable symbol with a plurality of scanning passes occurring at a scanning frequency;

sample, at a sampling frequency, an electrical signal corresponding to light reflected from the plurality of scanning passes, thereby producing samples associated with corresponding scanning passes; and

interleave samples associated with at least two scanning passes, thereby producing a representation in a memory, wherein the sampling frequency is proportional to the scanning frequency by a quotient of a product of a number of data samples in the representation and a natural number divided by an integer such that the quotient is an irreducible fraction.

43. The computer readable memory medium of claim 42 further comprising software code portions for causing the system to convert the representation from a time-domain format to a spatial-domain format.

44. The computer-readable memory medium of claim 42 wherein the natural number is one.

45. The computer-readable memory medium of claim 42 wherein the natural number is two.