BARCODE DECODING CHIP

• US 20110290877A1
• Filed: 05/31/2011
• Published: 12/01/2011
• Est. Priority Date: 06/01/2010
• Status: Active Grant

• Current Assignee: Newland Digital Technology Co., Ltd.
• Original Assignee: Fujian Newland Computer Company Limited
• Inventors: Lin, Zhilong, Zhang, Qingcai, Zheng, Chunguang, Hu, Lunyu, Zhuang, Guoliang, Liu, Rongsheng, Wu, Zhiyu, Chen, Wenchuan, Sun, Yali, Qiu, Yousen, Cai, Xiaodan, Wang, Xianfu, Guo, Dong, Cai, Qiang
• Granted Patent: US 8,596,538 B2
• Time in Patent Office: Days
• US Class Current: 235/436
• 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 7/1456 determining the orientation of the optical code with respect to the reader and correcting therefore
• CPC Class Codes: G06K 7/1469 using sub-pixel interpolation
• CPC Class Codes: G06K 7/1473 error correction
• CPC Class Codes: G06K 7/1491 the method including a reconstruction step, e.g. stitching two pieces of bar code together to derive the full bar code

Abstract

An exemplary barcode decoding chip includes a scan module, a boundary identification module, a direction identification module, a bar space boundary processing module, a symbol parameter identification module, a symbol character acquisition module, and a decoding module.

Claims

1. A barcode decoding chip, comprising:

(a) a scan module which generates scan coordinates corresponding to address bits in address memory space of a data storage unit, the scan module being configured for scanning barcode image in the data storage unit;

(b) a boundary identification module which reads the barcode image based on the scan coordinates and calculates bar space boundary points in the barcode image with the read image pixels;

(c) a direction identification module which calculates barcode direction with the bar space boundary points acquired by the boundary identification module;

(d) a bar space boundary processing module which processes barcode image based on the barcode direction to acquire bar space boundaries in the barcode image;

(e) a symbol parameter identification module which identifies symbol parameters of the barcode based on the bar space boundaries;

(f) a symbol character acquisition module which calculates symbol characters with the bar space boundaries and the symbol parameters; and

(g) a decoding module which converts the symbol characters into barcode information.

2. The barcode decoding chip of claim 1, wherein the scan module comprises a scan coordinate generation unit which generates initial scan coordinates, and a coordinate mapping transformation unit which maps the initial scan coordinates into the address memory space through coordinate transformation.

3. The barcode decoding chip of claim 1, wherein the boundary identification module calculates gray differences among the image pixel points to acquire the bar space boundary points of the barcode image.

4. The barcode decoding chip of claim 1, wherein the boundary identification module identifies barcode type based on the bar space boundary points of the barcode image.

5. The barcode decoding chip of claim 4, wherein the boundary identification module matches the bar space boundary points with the bar space proportion of start character or stop character of a candidate barcode to identify whether the candidate barcode exists in the barcode image.

6. The barcode decoding chip of claim 1, wherein the direction identification module compares the coordinate positions of the bar space boundary points to identify the feature relationship between the bar space boundary points , and calculates the barcode direction based on the coordinate values of the bar space boundary points lying in the same feature relationship.

7. The barcode decoding chip of claim 6, wherein the feature relationship comprises parallelogram feature or parallel lines feature.

8. The barcode decoding chip of claim 1, wherein the bar space boundary processing module comprises:

(a) a scan boundary acquisition unit which calculates scan boundaries based on the bar space boundary points and the barcode direction;

(b) a linear scan unit which selects scan start point and scan end point corresponding to the scan start point based on the scanning boundaries, and calculates coordinates of pixel points on a line between the scan start point and the scan end point, and

(c) a sub-pixel boundary calculation unit which calculates the coordinates of the bar space boundaries based on the coordinates of the pixel points and gray values of the pixel points.

9. The barcode decoding chip of claim 8, wherein the scan boundary acquisition unit takes the bar space boundary points as centers, extends outwards along the barcode direction, and establishes boundary regions, the boundary regions comprising the barcode boundary point and a set of pixel points near the barcode boundary points.

10. The barcode decoding chip of claim 9, wherein the bar space boundary processing module also comprises a line calculation unit, the line calculation unit used to acquire boundary lines corresponding to the boundary regions through Hough operation.

11. The barcode decoding chip of claim 10, wherein the line calculation unit employs several cordic iterative operation units connected in serial to perform Hough operation on the set of pixel points in order to acquire the coordinates of the line.

12. The barcode decoding chip of claim 10, wherein the scan boundary acquisition unit translates the boundary lines outwards along the barcode direction by a predetermined distance to obtain the scan boundaries.

13. The barcode decoding chip of claim 8, wherein the bar space boundary processing module also comprises a scan coordinate calculation unit, the line calculation unit derives the pixel point coordinates of the boundary line corresponding to the barcode boundary in the boundary region of the both sides of the barcode, and returns the results of the operation to the scan boundary acquisition unit.

14. The barcode decoding chip of claim 8, wherein the bar space boundary processing module also comprises a scan coordinate calculation unit, the scan coordinate calculation unit calculating coordinates of the pixel points on the line between the scan start point and the scan end point through Breshem algorithm.

15. The barcode decoding chip of claim 1, wherein the symbol parameters comprises one of the following:

the number of rows and the number of columns of the barcode, the row number and the column number of the barcode, the number of the bar space boundaries of the symbol characters, the bar space widths of the symbol characters, checking information or combination thereof.

16. The barcode decoding chip of claim 1, wherein the symbol parameters comprise one of the following:

the number of the bar space boundaries of symbol characters of the barcode, the bar space widths of the symbol characters, checking information or combination thereof.

17. The barcode decoding chip of claim 1, wherein the symbol character extraction module comprises a bar space determination unit, the bar space determination unit processing bar space boundary based on the symbol parameters, removing disturbing boundaries among the bar space boundaries, and acquiring valid bar space boundaries combination.

18. The barcode decoding chip of claim 17, wherein the symbol character extraction module also comprises a bar space value calculation unit, the bar space value calculation unit comparing the values of the bar space widths constituted by valid bar space boundaries combination to acquire the symbol characters.

19. The barcode decoding chip of claim 1, wherein the decoding module comprises:

(a) a code list storage unit which generates code list representing the corresponding relationship between the symbol characters and code words,

(b) a code word acquisition unit which acquires initial code words utilizing the received symbol characters according to the code list,

(c) a code word error correction unit which performs RS error correction on the initial code words to acquire correct code words, and

(d) a decoding unit which acquires correct symbol characters utilizing the correct code words based on the code list, and decodes character set corresponding to the correct symbol characters based on the correct symbol characters to acquire the barcode information.

20. The barcode decoding chip of claim 1, wherein the decoding module comprises:

(a) an error checking unit which checks the symbol characters for error; and

(b) a decoding unit which acquires barcode information from the character set corresponding to the symbol characters.