Guiding a scanning device to decode 2D symbols

• US 20040026511A1
• Filed: 08/05/2003
• Published: 02/12/2004
• Est. Priority Date: 08/07/2002
• Status: Active Grant

• Current Assignee: Ambir Technology Incorporated, Shenzhen Syscan Technology Company Limited
• Original Assignee: Syscan Incorporated (Document Capture Technologies, Inc.), Shenzhen Syscan Technology Company Limited
• Inventors: Lv, Ying-Feng, Chang, Zhi-Guo, Cheung, Wai, Ding, Shillin
• Granted Patent: US 6,802,450 B2
• Time in Patent Office: Days
• US Class Current: 235/462.1
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 7/1443 locating of the code in an image

Abstract

To facilitate the decoding of a 2D symbol (e.g., PDF417), a plurality of positioning lines are attached to the 2D symbol. Depending on implementation, these substantially parallel positioning lines may be provided on at least one side of the symbol or superimposed on the symbol. A scanning device is provided to capture an image of the symbol together with these positioning lines that are then detected to determine an orientation of the 2D symbol. In some cases, these positioning lines are used to correct images with distortion.

Claims

1. A method for guiding a scanning device to decode a 2D symbol, the method comprising:

providing a set of substantially parallel positioning lines to the 2D symbol, the positioning lines having a different slope than a horizontal axis of the 2D bar-code; and

scanning the 2D symbol together with positioning lines to produce a scanned image.

2. The method as recited in claim 1, wherein the positioning lines are provided on at least one side of the 2D symbol.

3. The method as recited in claim 1, wherein the positioning lines are superimposed upon the 2D symbol, and in a color different from a color of bars in the 2D symbol.

4. The method as recited in claim 1, further comprising determining an orientation of the 2D symbol in the scanner image in reference to the positioning lines.

5. The method as recited in claim 4, wherein at least one of the positioning lines includes a plurality of teeth.

6. The method as recited in claim 5, wherein the teeth is used to correct distortion in the scanned image.

7. The method as recited in claim 1, wherein the positioning lines are in a color different from that of bars in the 2D symbol.

8. The method as recited in claim 7, wherein the color absorbs first illumination from the scanning device.

9. The method as recited in claim 7, wherein the color reflects second illumination from the scanning device.

10. A scanning device for decoding a 2D bar-code attached with a set of equally spaced positioning lines, the scanning device comprising:

a signal processing chip;

a document detection module connecting to the processing chip for sending a paper signal when the 2D symbol presents and exists;

an image sensor sensing the 2D symbol and producing analog signals;

an analog-to-digital conversion (ADC) module receiving and digitizing the analog signals from the image sensor to produce a digital image thereof in a memory space; and

a flash memory for storing a decoding software, wherein the decoding software is configured to perform operations of;

detecting the positioning lines in the digital image;

determining a slope of the positioning lines with respect to a slope of the 2D symbol; and

determining an orientation of the 2D symbol.

11. The scanning device as recited in claim 10, wherein at least one of the positioning lines includes a plurality of teeth.

12. The scanning device as recited in claim 11, wherein the teeth is used to correct distortion in the scanned image.

13. The scanning device as recited in claim 10, wherein the positioning lines are in a color different from that of bars in the 2D symbol.

14. The scanning device as recited in claim 13, wherein the color absorbs first illumination from the scanning device.

15. The scanning device as recited in claim 13, wherein the color reflects second illumination from the scanning device.