Systems and methods for decoding two-dimensional matrix symbols

Patent metadata

Field	Value
Publication number	US-2016140374-A1
Application number	US-201514944248-A
Country	US
Kind code	A1
Filing date	Nov 18, 2015
Priority date	Nov 18, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

Systems and methods for reading a two-dimensional matrix symbol or for determining if a two-dimensional matrix symbol is decodable are disclosed. The systems and methods can include a data reading algorithm that receives an image, locates at least a portion of the data modules within the image without using a fixed pattern, fits a model of the module positions from the image, extrapolates the model resulting in predicted module positions, determines module values from the image at the predicted module positions, and extracts a binary matrix from the module values.

First claim

We claim:

1 . A system for reading a two-dimensional matrix symbol including data modules each having a module value and a module position, the two-dimensional matrix symbol encoding a data set, the system comprising:
an imaging device, the imaging device configured to acquire an image containing at least a portion of the two-dimensional matrix symbol; a processor, the processor operatively coupled to the imaging device, the processor configured to execute a data reading algorithm, wherein the data reading algorithm receives the image, locates at least a portion of the data modules within the image without using a fixed pattern, fits a model of the module positions from the image, extrapolates the model resulting in predicted module positions, determines module values from the image at the predicted module positions, and extracts a binary matrix from the module values; and a binary matrix decoder operatively coupled to the processor, the binary matrix decoder configured to execute a decoding algorithm that decodes the binary matrix.

2 . The system of claim 1 , wherein the data reading algorithm corrects errors in the binary matrix using an error correction routine.

3 . The system of claim 1 , wherein the system includes an illuminator that illuminates a target of the image with one or more illumination features.

4 . The system of claim 3 , wherein the data reading algorithm uses the illumination features to locate at least a portion of the data modules within the image.

5 . The system of claim 1 , wherein locating at least a portion of the data modules includes identifying one or more salient features of the data modules selected from the group consisting of shape, the presence or absence of a saddle, the presence or absence of a corner, the presence or absence of a dot, a gradient, a histogram, a wavelet, and combinations thereof.

6 . The system of claim 1 , wherein the processor or binary matrix decoder are configured to extrapolate or decode multiple symbology types.

7 . The system of claim 6 , wherein the multiple symbology types are selected from the group consisting of Data Matrix, QR-Code, Aztec Code, MaxiCode, and combinations thereof.

8 . The system of claim 1 , wherein the data reading algorithm includes attributes of the two-dimensional matrix symbol.

9 . The system of claim 1 , wherein the data reading algorithm can be executed by a single command to the processor.

10 . A method of reading a two-dimensional matrix symbol including data modules each having a module value and a module position, the two-dimensional matrix symbol encoding a data set, the method comprising:
receiving an image at a processor, the image containing at least a portion of the two-dimensional matrix symbol; locating, using the processor, at least a portion of the data modules within the image without using a fixed pattern; fitting, using the processor, a model to at least a portion of the module positions from the image; extrapolating, using the processor, the model to define predicted module positions; determining, using the processor, the module values from the image at the predicted module positions; extracting, using the processor, a binary matrix from the module values; and decoding the binary matrix.

11 . The method of claim 10 , the method further comprising correcting, using the processor, errors in the binary matrix using an error correction routine.

12 . The method of claim 10 , the method further comprising illuminating the two-dimensional matrix symbol or a location near the two-dimensional matrix symbol.

13 . The method of claim 10 , wherein locating at least a portion of the data modules includes identifying one or more salient features of the data modules selected from the group consisting of shape, the presence or absence of a saddle, the presence or absence of a corner, the presence or absence of a dot, a gradient, a histogram, a wavelet, and combinations thereof.

14 . The method of claim 10 , wherein the method includes attempting to extrapolate or decode multiple symbology types.

15 . The method of claim 14 , wherein the multiple symbology types are selected from the group consisting of Data Matrix, QR-Code, Aztec Code, MaxiCode, and combinations thereof.

16 . The method of claim 10 , the method further comprising training the processor to contain one or more attributes of the two-dimensional matrix symbol prior to receiving the image.

17 . The method of claim 10 , wherein the method can be executed by a single command to the processor.

18 . A system for determining if a two-dimensional matrix symbol is decodable, the two-dimensional matrix symbol including data modules each having a module value and a module position, the system comprising:
an imaging device, the imaging device configured to acquire an image containing the two-dimensional matrix symbol; a processor, the processor operatively coupled to the imaging device, the processor configured to execute a data reading algorithm, wherein the data reading algorithm receives the image, locates at least a portion of the data modules within the image without using a fixed pattern, fits a model of the module positions from the image, extrapolates the model resulting in predicted module positions, determines module values from the image at the predicted module positions, and extracts a binary matrix from the module values,
wherein the data reading algorithm includes a frequency-domain analysis.

19 . The system of claim 18 , wherein the data reading algorithm fits the model using a frequency-domain analysis.

20 . The system of claim 18 , wherein the system further comprises a binary matrix decoder operatively coupled to the processor, the binary matrix decoder configured to execute a decoding algorithm that decodes the binary matrix.

Assignees

• Cognex Corp

Inventors

• Ye Xiangyun
• Wang Xianju
• Negro James A

Classifications

• G06K7/146

  the method including quality enhancement steps · CPC title

• G06K7/1491

  the method including a reconstruction step, e.g. stitching two pieces of bar code together to derive the full bar code · CPC title

• G06K7/1443 Primary

  locating of the code in an image · CPC title

• G06K7/10821

  further details of bar or optical code scanning devices · CPC title

• G06K7/1417 Primary

  2D bar codes · CPC title