Clock free two-dimensional barcode and method for printing and reading the same
First Claim
1. A method of encoding information for printing on a printed medium for later decoding without the use of clocking bits and without the use of a border, comprising the steps of:
- converting said information into a data stream having a sequence of "0" and "1" characters representing data bits;
randomizing said data stream to produce a randomized data stream having a sequence of "0" and "1" characters;
formatting the randomized data stream into a two-dimensional bitmap of rows and columns including only the randomized data stream bits; and
printing the formatted bitmap onto said printed medium.
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Accused Products
Abstract
Inventive two-dimensional barcodes, each having encoded digital information in a bitmap representing preferably randomized encoded data bits, are printed onto a printed medium. The bitmap may further include a plurality of block identifiers, spaced a predetermined number of encoded data bits apart, which are used to make corrections for missing or added data bits when the barcode is decoded. Upon decoding a barcode printed on the printed media, the digital information is scanned and the number of horizontal and vertical edges in each respective column and row of the barcode are determined. An edge is determined by selecting a pixel and determining if the two pixels adjacent to the selected pixel are of different colors. After all of the edges are counted, selected groups of columns and rows are analyzed to determine local minimas in the number of counted horizontal and vertical edges in each selected group which provide the column and row center line for each selected group. Thereafter, the binary data located at the intersection of each column and row center line are read out to produce a signal representative of the encoded digital information in the printed barcode.
162 Citations
12 Claims
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1. A method of encoding information for printing on a printed medium for later decoding without the use of clocking bits and without the use of a border, comprising the steps of:
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converting said information into a data stream having a sequence of "0" and "1" characters representing data bits; randomizing said data stream to produce a randomized data stream having a sequence of "0" and "1" characters; formatting the randomized data stream into a two-dimensional bitmap of rows and columns including only the randomized data stream bits; and printing the formatted bitmap onto said printed medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer-readable information storage medium having encoded thereon a two-dimensional data barcode comprising a bitmap formatted representation of digital encoded information having a selected pixel row and column length, and having a plurality of block identifiers, each having a predetermined value and each positioned at a predetermined location such that each block identifier being spaced a predetermined number of rows or columns apart to permit automatic correction of said encoded information decoded from said barcode if, in the decoded information, the number of rows or columns between two sequential block identifiers does not equal said predetermined number.
- 10. A computer-readable information storage medium having encoded thereon a two-dimensional data barcode comprising a bitmap formatted representation of randomized encoded information having a selected pixel row and column length, and having a plurality of block identifiers, each having a predetermined value and each positioned at a predetermined location such that each block identifier being spaced a predetermined number of rows or columns apart to permit automatic correction of said encoded information decoded from said barcode if, in the decoded information, the number of rows or columns between two sequential block identifiers does not equal said predetermined number.
Specification