Method for reading out symbol information and device for reading out symbol information

• US 7,380,718 B2
• Filed: 12/21/2005
• Issued: 06/03/2008
• Est. Priority Date: 12/21/2004
• Status: Expired due to Fees

• Current Assignee: Nidec Sankyo Corporation (Nidec Corporation)
• Original Assignee: Nidec Sankyo Corporation (Nidec Corporation)
• Inventors: Nakamura, Hiroshi
• Primary Examiner(s): ST CYR, DANIEL
• Application Number:
  US11/316,546
• Publication Number:
  US 20060175414A1
• Time in Patent Office: 895 Days
• Field of Search: 235/462.01, 235/462.12, 23546216-46219, 235/462.25, 235/494, 23546207-46211, 382/245, 382/289
• US Class Current: 235/462.01
• 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 7/1486 Setting the threshold-width for bar codes to be decoded

Abstract

To provide a method for reading out symbol information and a device for reading out symbol information which are able to prevent a decline in decoding reliability by reducing noise caused by a quantized error, localized contaminations or the like. The method for reading out symbol information may comprise a process in which the image data, obtained by imaging the symbol information such as bar codes and the like, are converted to corrected image data having zero angle of inclination; a smoothing process in which the corrected image data are smoothed; and a column specifying process in which breakpoints of said symbol information column are specified by computing the total sum in the row direction on the smoothed corrected image data.

Claims

1. A method for reading out symbol information in which symbol information is read by processing image data obtained by imaging the symbol information recorded on a medium comprising:

performing an angle changing process in which said image data are converted to corrected image data having zero angle of inclination;

performing a smoothing process in which said corrected image data are smoothed;

performing a projection process in which said corrected image data smoothed by said smoothing process are totally summed up in a row direction and successively projected in a column direction; and

performing a column specifying process in which breakpoints of a symbol information column are specified by a projected result in the column direction which is obtained by the projection process.

2. The method for reading out symbol information as described in claim 1 further comprising a row specifying process comprising:

setting a line group which comprises adjacent multiple lines which are disposed in the row direction and each of the adjacent multiple lines is extended in the column direction on the corrected image data;

computing correlation matrix values of the line group on a basis of the corrected image data to obtain a judgment value corresponding to the line group;

relatively moving the line group successively in the row direction to obtain respective judgment values based on the correlation matrix values; and

specifying breakpoints of rows of the symbol information based on the judgment values.

3. The symbol information readout method as described in claim 2 wherein said symbol information comprises a start pattern, which indicates the start of said symbol information, and a stop pattern, which indicates the end of said symbol information;

and said symbol information readout method further comprises performing a detection process in which said start pattern or said stop pattern is detected by computing a degree of similarity between a prescribed reference width data and width data in the column direction of bars and spaces for one column of the corrected image data.

4. The symbol information readout method as described in claim 1 wherein said symbol information comprises a start pattern, which indicates the start of said symbol information, and a stop pattern, which indicates the end of said symbol information;

and said symbol information readout method further comprises performing a detection process in which said start pattern or said stop pattern is detected by computing a degree of similarity between a prescribed reference width data and width data in the column direction of bars and spaces for one column of the corrected image data.

5. The symbol information readout method as described in claim 1 further comprising performing a judging process which judges whether or not a total number of bars and spaces of one column on the corrected image data is equal to a number set in advance to detect abnormality of the one column.

6. A symbol information readout device comprising a readout means for performing:

an angle changing process in which said image data are converted to corrected image data having zero angle of inclination;

a smoothing process in which said corrected image data are smoothed;

a projection process in which said corrected image data smoothed by said smoothing process are totally summed up in a row direction and successively projected in a column direction; and

a column specifying process in which breakpoints of a symbol information column are specified by a projected result in the column direction which is obtained by the projection process.

7. The symbol information readout device as described in claim 6 wherein said readout means to read out said symbol information comprises a tightly adhered stack-type one dimensional imaging element.

8. A method for reading out symbol information in which symbol information is read, the method comprising:

processing image data obtained by imaging the symbol information recorded on a medium comprising;

a projection process in which corrected image data smoothed by a smoothing process are totally summed up in a row direction and successively projected in a column direction;

a column specifying process in which breaking points of a column of said symbol information are specified by a projected result in the column direction which is obtained by the projection process;

and performing a boundary determination process in which, based on a comparison of breaking points of a column specified by said column specifying process with an end of a measured column, the boundary of each row column is determined.

9. A symbol information readout device comprising a means for performing:

a projection process in which corrected image data smoothed by a smoothing process are totally summed up in a row direction and successively projected in a column direction;

a column specifying process in which breaking points of a column of said symbol information are specified by a projected result in the column direction which is obtained by the projection process;

and a boundary determination process in which, based on a comparison of breaking points of a column specified by said column specifying process with an end of a measured column, the boundary of each row column is determined.

10. The symbol information readout device as described in claim 9 further comprising a tightly adhered stack-type one dimensional imaging element which images said symbol information.