Omnidirectional reading of two-dimensional symbols
AssigneeSymbol Technologies, Inc.
InventorStephen J. Shellhammer
Life of this patent
Estimating the term…
Abstract
A method and apparatus for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords. The two dimensional bar code is scanned with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows. A determination if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line is made and the orientation of the scanning pattern is adjusted to reduce the absolute value of the angle.
Claims15
A method for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising the steps of:
- scanning the two dimensional bar code with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows;
- determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and
- adjusting the orientation of the scanning pattern to reduce the absolute value of the angle;
- wherein the bar code has row indicator code words in each row and wherein the step of determining comprises decoding the row indicator codewords read by the at least one line and determining the slope of the angle therefrom.
A method for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising the steps of:
- scanning the two dimensional bar code with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows;
- determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and
- adjusting the orientation of the scanning pattern to reduce the absolute value of the angle;
- wherein the bar code has codewords that are divided into a plurality of clusters and wherein each row uses codewords of only one cluster and where the step of determining comprises decoding the codewords read by the at least one line to determine the cluster of each codeword and determining the slope of the angle therefrom.
A method for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising the steps of:
- scanning the two dimensional bar code with a scanning pattern oriented such that a plurality of lines thereof cross the bar code rows;
- determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and
- adjusting the orientation of the scanning pattern to reduce the absolute value of the angle;
- wherein the step of scanning comprises scanning the bar code with a locating pattern to determine the position of the bar code to initially orient the scanning pattern with respect thereto.
A system for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising:
- a pattern generator for generating a scanning pattern oriented to scan the two dimensional bar code such that a plurality of scan lines cross the bar code rows;
- a processor for determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and an alignment mechanism based upon the determined angle for adjusting the orientation of the scanning pattern generated by the pattern generator to reduce the absolute value of the angle;
- wherein the bar code has row indicator code words in each row and wherein the processor has a decoder for decoding the row indicator codewords read by the at least one line to determine the slope of the angle therefrom.
A system for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising:
- a pattern generator for generating a scanning pattern oriented to scan the two dimensional bar code such that a plurality of scan lines cross the bar code rows;
- a processor for determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line, and an alignment mechanism based upon the determined angle for adjusting the orientation of the scanning pattern generated by the pattern generator to reduce the absolute value of the angle;
- wherein the bar code has codewords that are divided into a plurality of clusters and wherein each row uses codewords of only one cluster and where the processor has a decoder for decoding the codewords read by the at least one line to determine the cluster of each codeword and to determine the slope of the angle therefrom.
A system for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising:
- a pattern generator for generating a scanning pattern oriented to scan the two dimensional bar code such that a plurality of scan lines cross the bar code rows;
- a processor for determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and an alignment mechanism based upon the determined angle for adjusting the orientation of the scanning pattern generated by the pattern generator to reduce the absolute value of the angle;
- wherein the system is incorporated in a hand held scanner which is initially manually oriented the to the bar code.
A system for aligning a scan pattern to a two dimensional bar code having parallel rows of codewords, comprising:
- a pattern generator for generating a scanning pattern oriented to scan the two dimensional bar code such that a plurality of scan lines cross the bar code rows;
- a processor for determining if there is a non-zero angle between at least one of the plurality of lines and the rows by decoding codewords in rows intersected by the at least one line;
- and an alignment mechanism based upon the determined angle for adjusting the orientation of the scanning pattern generated by the pattern generator to reduce the absolute value of the
- further comprising a locating pattern for generating a locating pattern and a bar code position calculator for determining the position of the bar code to initially orient the scanning pattern with respect thereto.
Dependencies are inferred from the claim text.