Method and apparatus for decoding two-dimensional bar code
AssigneeSymbol Technologies, Inc.
InventorsStephen J. Shellhammer, Arman Nikzad, Jerome Swartz
Life of this patent
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Abstract
A method and apparatus for decoding a two-dimensional bar code symbol using a charge-coupled device (CCD) camera, charge-modulation device (CMD) camera, or other bar code reading device such as a hand-held reader, light pen or wand, scan mouse, or stationary laser scanner. The CCD/CMD camera or reading device optically images the bar code symbol to obtain digital image data, which is stored in a memory. The location and orientation of the two-dimensional bar code
Claims12
A system for reading and decoding a two-dimensional bar code symbol having rows of bar-coded information in which data is represented in each row by a plurality of codewords, each row including a predetermined control codeword, the codewords being formed of a plurality of modules, comprising:
- a two-dimensional imaging camera for optically imaging the bar code symbol to obtain lines of image data corresponding to a field of view including the bar code symbol;
- a memory for storing the lines of image data;
- means for determining an orientation of the two-dimensional bar code symbol in the field of view by locating control codewords in at least two positions in the image data;
- means for determining a sequence of lines passing through the rows of the bar code symbol in the image data from the orientation determined from the positions of the control codewords;
- and
- means for scanning the two-dimensional bar code symbol in the image data along the sequence of lines line to read the codewords.
A method for reading and decoding a two-dimensional bar code symbol having rows of bar-coded information in which data is represented in each row by a plurality of codewords, each row including a predetermined control codeword which is the same for each row, the codewords being formed of a plurality of modules, the method comprising the steps of:
- optically imaging the two-dimensional bar code symbol using a two-dimensional imaging camera to obtain lines of image data corresponding to a field of view including the bar code symbol;
- storing the lines of image data in a memory;
- determining an orientation of the two-dimensional bar code symbol in the field of view by locating control codewords in at least two positions in the image data;
- determining a sequence of lines passing through the rows of the bar code symbol in the image data from the orientation derived from the positions of the control codewords;
- and
- scanning the two-dimensional bar code symbol in the image data along the sequence of lines to read the codewords.
Dependencies are inferred from the claim text.