Camera-based barcode recognition

• US 7,172,124 B2
• Filed: 03/10/2005
• Issued: 02/06/2007
• Est. Priority Date: 03/10/2005
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Wang, Jian, Zhang, Chunhui
• Primary Examiner(s): Le; Thien M.
• Assistant Examiner(s): Labaze; Edwyn
• Application Number:
  US11/077,056
• Publication Number:
  US 20060202039A1
• Time in Patent Office: 698 Days
• Field of Search: 235/462.16, 235/462.19, 235/462.01, 235/462.24, 235/462.25, 235/462.29, 235/470
• US Class Current: 235/462.16
• 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

Embodiments of the invention relate to decoding encoded barcode information from a camera-captured image by generating a binarized sequence from the camera-captured image and decoding the encoded barcode information from the binarized sequence. The camera-captured image is transformed into a preprocessed grayscale image, reducing noise and enhancing contrast between bars and spaces in the preprocessed image. A barcode orientation is identified that is parallel to bars in the preprocessed image. A projected sequence is generated by projecting pixels of the preprocessed image along the barcode orientation. The binarized sequence is generated by applying a threshold to detected peaks and valleys of the projected sequence. A barcode-encoding sequence is generated, from the binarized sequence, in which each barcode bar module and each barcode space module is represented by a single respective bit in the barcode-encoding sequence. The barcode encoded information is extracted from the barcode-encoding sequence.

Claims

1. A system that decodes encoded barcode information from a camera-captured image, the system comprising:

an image-processing module that generates a binarized sequence from the camera-captured image; and

a binary-sequence processing module that decodes the encoded barcode information from the binarized sequence, wherein the binary-sequence-processing module includes a binary-sequence-recognition module that generates, from the binarized sequence, a barcode-encoding sequence in which each barcode bar module and each barcode space module is represented by a single respective bit in the barcode-encoding sequence.

2. The system of claim 1, wherein the image-processing module comprises an image-preprocessing module that transforms the camera-captured image into a preprocessed grayscale image, reduces noise in the preprocessed image, and enhances contrast between bars and spaces in the preprocessed image.

3. The system of claim 2, wherein the image-preprocessing module binarizes an image-binarization area that is located near a center of the preprocessed image.

4. The system of claim 1, wherein the image-processing module comprises a barcode-orientation-identification module that identifies a barcode orientation that is parallel to bars in the preprocessed image.

5. The system of claim 4, wherein the image-processing module comprises a barcode-image-projection module that generates a projected sequence by projecting pixels of the preprocessed image along the barcode orientation.

6. The system of claim 5, wherein the image-processing module comprises a sequence-binarization module that generates the binarized sequence by applying a threshold to detected peaks and valleys of the projected sequence.

7. The system of claim 1, wherein the binary-sequence-processing module comprises a barcode-decoding module that extracts the barcode encoded information from the barcode-encoding sequence.

8. A computer-readable medium having computer-executable instructions for decoding encoded barcode information from a camera-captured image by performing steps comprising:

generating a binarized sequence from the camera-captured image;

generating, from the binarized sequence, a barcode-encoding sequence in which each barcode bar module and each barcode space module is represented by a single respective bit in the barcode-encoding sequence; and

decoding the encoded barcode information form the binarized sequence.

9. The computer-readable medium of claim 8, having further computer-executable instructions for transforming the camera-captured image into a preprocessed grayscale image, reducing noise in the preprocessed image, and enhancing contrast between bars and spaces in the preprocessed image.

10. The computer-readable medium of claim 9, having further computer-executable instructions for identifying a barcode orientation that is parallel to bars in the preprocessed image.

11. The computer-readable medium of claim 10, having further computer-executable instructions for generating a projected sequence by projecting pixels of the preprocessed image along the barcode orientation.

12. The computer-readable medium of claim 11, having further computer-executable instructions for generating the binarized sequence by applying a threshold to detected peaks and valleys of the projected sequence.

13. The computer-readable medium of claim 8, having further computer-executable instructions for extracting the barcode encoded information from the barcode-encoding sequence.

14. A system for decoding encoded barcode information from a camera-captured image, the system comprising:

means for generating a binarized sequence from the camera-captured image;

means for generating, from the binarized sequence, a barcode-encoding sequence in which each barcode bar module and each barcode space module is represented by a single respective bit in the barcode-encoding sequence; and

means for decoding the encoded barcode information from the binarized sequence.

15. The system of claim 14, further comprising:

means for transforming the camera-captured image into a preprocessed grayscale image;

means for reducing noise in the preprocessed image; and

means for enhancing contrast between bars and spaces in the preprocessed image.

16. The system of claim 15, further comprising:

means for identifying a barcode orientation that is parallel to bars in the preprocessed image;

means for generating a projected sequence by projecting pixels of the preprocessed image along the barcode orientation; and

means for generating the binarized sequence by applying a threshold to detected peaks and valleys of the projected sequence.

17. The system of claim 14, further comprising means for extracting the barcode encoded information from the barcode-encoding sequence.