Enhanced virtual scan line processing

• US 8,172,145 B2
• Filed: 11/18/2008
• Issued: 05/08/2012
• Est. Priority Date: 11/20/2007
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Rudeen, Robert William
• Primary Examiner(s): Le, Thien M.
• Assistant Examiner(s): Marshall, Christle
• Application Number:
  US12/273,381
• Publication Number:
  US 20090127326A1
• Time in Patent Office: 1,267 Days
• Field of Search: 235/462.08, 235/462.12, 235/462.09
• US Class Current: 235/462.08
• CPC Class Codes: G06K 7/10554 Moving beam scanning
• CPC Class Codes: G06K 7/10594 Beam path
• 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 7/1452 detecting bar code edges
• CPC Class Codes: G06V 10/22 by selection of a specific region containing or referencing a pattern; Locating or processing of specific regions to guide the detection or recognition

Abstract

Systems and methods for decoding a barcode or other optical code include identifying one or more sub-regions of image data that contain promising data based on a first set of edge detection parameters, transferring the promising data from a first memory location to a new memory location for further processing, and decoding the promising data based on a different set of edge detection parameters.

Claims

1. A method of decoding an optical code, comprising:

receiving a first data set corresponding to a sub-region of an image of the optical code;

detecting a first set of edge transition locations in the first data set using a first set of edge detection parameters;

based on the first set of edge transition locations, determining whether the first data set contains promising data;

in response to determining that the first data set contains promising data, determining a different set of edge transition locations in the promising data using a different set of edge detection parameters, wherein the different set of edge transition locations in the promising data are determined from the first data set independent of acquiring another image of the optical code; and

decoding the promising data based on the different set of edge transition locations.

2. The method of claim 1, further comprising:

acquiring the image of the optical code via an imager of a data reader.

3. The method of claim 1, further comprising:

stitching the decoded promising data together with other decoded data to form a decoded dataset representing the optical code; and

storing the decoded dataset representing the optical code.

4. The method of claim 1 wherein the sub-region comprises a virtual scan line.

5. The method of claim 1 wherein the step of determining whether the first data set contains promising data comprises identifying at least one valid character in the first data set.

6. The method of claim 1 wherein the step of determining whether the first data set contains promising data comprises identifying an overhead character in the first data set.

7. The method of claim 1 wherein the step of determining whether the first data set contains promising data comprises identifying a total number of edge transitions in the first data set that deviates from an expected number of edge transitions.

8. The method of claim 1 wherein the step of determining whether the first data set contains promising data comprises determining whether a total number of edge transitions in the first set of edge transition locations exceeds a predetermined amount.

9. The method of claim 1 wherein the different set of edge detection parameters includes a different minimum modulation percentage than that used for the first set of edge detection parameters.

10. The method of claim 1 wherein the different set of edge detection parameters includes a different window threshold than that used for the first set of edge detection parameters.

11. The method of claim 1, further comprising:

in response to determining that the first data set contains promising data, amplifying one or more spatial frequencies of the promising data and determining a different set of edge transition locations in the promising data resulting from the amplification.

12. The method of claim 1 wherein the first data set corresponding to the sub-region is selected from a set of sub-regions orientated with respect to one another in a pattern, and further comprising:

in response to determining that the first data set contains promising data, altering the pattern in a subsequent data frame to gather additional data of the optical code proximate the sub-region containing the promising data.

13. The method of claim 1 wherein the step of determining whether the first data set contains promising data comprises identifying a missing edge transition or an additional edge transition in the first set of edge transition locations.

14. The method of claim 1, further comprising:

decoding the first data set based on the first set of edge transition locations to establish a partially decoded data set including (1) one or more decoded characters that are decodable based on the first set of edge transition locations and (2) one or more undecoded characters that are not decodable based on the first set of edge transition locations;

decoding the first data set based on the different set of edge transition locations to establish a decoded data set including one or more decoded characters that are decodable based on the different set of edge transition locations, wherein the one or more undecoded characters that are not decodable based on the first set of edge transition locations are decodable based on the different set of edge transition locations;

correlating the one or more decoded characters from the partially decoded data set and the decoded data set; and

substituting the one or more undecoded characters in the partially decoded data set with the corresponding decoded characters from the decoded data set.

15. A non-transitory machine-readable storage medium for use with an optical code reader, wherein the machine-readable storage medium has instructions stored thereon for decoding an optical code in response to receiving a first data set corresponding to a sub-region of an acquired image of the optical code, the instructions comprising:

instructions for detecting a first set of edge transition locations in the first data set using a first set of edge detection parameters;

instructions for, based on the first set of edge transition locations, determining whether the first data set contains promising data;

instructions for, in response to determining that the first data set contains promising data, determining a different set of edge transition locations in the promising data using a different set of edge detection parameters, wherein the different set of edge transition locations in the promising data are determined from the first data set independent of acquiring another image of the optical code; and

instructions for decoding the promising data based on the different set of edge transition locations.

16. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters;

varying the first set of edge detection parameters to form a different set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters, wherein the promising data is decoded based on the different set of edge detection parameters independent of acquiring another image of the optical code.

17. The method of claim 16, further comprising:

stitching the decoded promising data together with other decoded data to form a decoded dataset representing the optical code; and

storing the decoded dataset representing the optical code.

18. The method of claim 16, further comprising:

storing the promising data in a memory before the step of decoding the promising data based on the different set of edge detection parameters to thereby allow promising data in other sub-regions of the acquired image to be identified based on the first set of edge detection parameters.

19. The method of claim 16 wherein the step of decoding the promising data based on a different set of edge detection parameters is performed while additional sub-regions of the optical code are acquired.

20. The method of claim 16 wherein the step of identifying at least one sub-region that contains promising data comprises determining whether a total number of edge transitions in the optical code exceeds a predetermined amount.

21. The method of claim 16 wherein varying the first set of edge detection parameters comprises altering a window threshold of the first set of edge detection parameters.

22. The method of claim 16 wherein the step of identifying at least one sub-region that contains promising data comprises identifying at least one valid character or an overhead character in the optical code.

23. The method of claim 16 wherein the step of identifying at least one sub-region that contains promising data comprises identifying a missing edge transition or an additional edge transition in the optical code.

24. The method of claim 16 wherein varying the first set of edge detection parameters comprises altering a minimum modulation percentage of the first set of edge detection parameters.

25. The method of claim 16 wherein the step of identifying at least one sub-region that contains promising data comprises identifying a total number of edge transitions in the optical code that deviates from an expected number of edge transitions.

26. The method of claim 16, further comprising:

in response to identifying promising data based on the first set of edge detection parameters, amplifying one or more spatial frequencies of the promising data and determining a set of edge transition locations in the promising data resulting from the amplification.

27. A system for reading optical codes, comprising:

an image acquisition component for acquiring an image of an optical code;

an edge detection component for determining a first set of edge transition locations in data corresponding to a sub-region of the acquired image of the optical code using a first set of edge detection parameters;

a decoder component for determining whether the data contains promising data based on the first set of edge transition locations; and

a promising sub-region memory for storing the promising data,

wherein the edge detection component determines a different set of edge transition locations in the promising data using a different set of edge detection parameters, wherein the different set of edge transition locations in the promising data are determined from the data corresponding to the sub-region of the acquired image of the optical code independent of acquiring another image of the optical code, and wherein the decoder component decodes the promising data based on the different set of edge transition locations.

28. The system of claim 27 wherein the decoder component determines that the data contains promising data by identifying at least one valid character or an overhead character in the data.

29. The system of claim 27 wherein the decoder component determines that the data contains promising data by identifying a missing edge transition or an additional edge transition in the data.

30. The system of claim 27 wherein the decoder component determines that the data contains promising data by determining that a total number of edge transitions in the first set of edge transition locations exceeds a predetermined amount.

31. The system of claim 27 wherein the different set of edge detection parameters includes a different minimum modulation percentage than the first set of edge detection parameters.

32. The system of claim 27 wherein the decoder component determines that the data contains promising data by identifying a total number of edge transitions in the data that deviates from an expected number of edge transitions.

33. The system of claim 27 wherein the different set of edge detection parameters includes a different window threshold than the first set of edge detection parameters.

34. The system of claim 27, wherein, in response to determining that the data contains promising data based on the first set of edge transition locations, the decoder component amplifies one or more spatial frequencies of the promising data and determines a different set of edge transition locations in the promising data resulting from the amplification.

35. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters, wherein identifying at least one sub-region that contains promising data comprises identifying at least one valid character or an overhead character in the optical code;

varying the first set of edge detection parameters to form a different set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters.

36. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters, wherein identifying at least one sub-region that contains promising data comprises identifying a missing edge transition or an additional edge transition in the optical code;

varying the first set of edge detection parameters to form a different set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters.

37. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters;

varying the first set of edge detection parameters to form a different set of edge detection parameters, wherein varying the first set of edge detection parameters comprises altering a minimum modulation percentage of the first set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters.

38. A method of decoding an optical code, comprising:

receiving a first data set corresponding to a sub-region of an image of the optical code;

detecting a first set of edge transition locations in the first data set using a first set of edge detection parameters;

based on the first set of edge transition locations, determining whether the first data set contains promising data;

in response to determining that the first data set contains promising data, determining a different set of edge transition locations in the promising data using a different set of edge detection parameters;

decoding the promising data based on the different set of edge transition locations;

decoding the first data set based on the first set of edge transition locations to establish a partially decoded data set including (1) one or more decoded characters that are decodable based on the first set of edge transition locations and (2) one or more undecoded characters that are not decodable based on the first set of edge transition locations;

decoding the first data set based on the different set of edge transition locations to establish a decoded data set including one or more decoded characters that are decodable based on the different set of edge transition locations, wherein the one or more undecoded characters that are not decodable based on the first set of edge transition locations are decodable based on the different set of edge transition locations;

correlating the one or more decoded characters from the partially decoded data set and the decoded data set; and

substituting the one or more undecoded characters in the partially decoded data set with the corresponding decoded characters from the decoded data set.

39. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters, wherein identifying at least one sub-region that contains promising data comprises identifying a total number of edge transitions in the optical code that deviates from an expected number of edge transitions;

varying the first set of edge detection parameters to form a different set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters.

40. A method of reading optical codes, comprising the steps of:

identifying at least one sub-region of an acquired image of an optical code containing promising data based on a first set of edge detection parameters;

in response to identifying promising data based on the first set of edge detection parameters, amplifying one or more spatial frequencies of the promising data and determining a set of edge transition locations in the promising data resulting from the amplification;

varying the first set of edge detection parameters to form a different set of edge detection parameters; and

decoding the promising data based on the different set of edge detection parameters.