System and method for identifying erasures in a 2d symbol

A method for identifying a codeword in a two-dimensional machine-readable symbol as an erasure, the two-dimensional symbol having data that is encoded with a mask, the method, comprising:

• comparing at least an unmasked codeword in the two-dimensional symbol with at least a portion of a mask,
• wherein the mask was used for encoding data in the two-dimensional symbol,
• wherein the unmasked codeword is generated by applying at least a portion the mask to the codeword, and
• wherein the portion of the mask corresponds with a location of the codeword in the two-dimensional symbol;
• and,
• determining whether the codeword is an erasure based on the comparison.

An apparatus for identifying a codeword as an erasure in a 2D symbol, the 2D symbol having data that is encoded with a mask, the apparatus, comprising:

• a mask identifier module operable to identify the mask used for encoding the data in the codeword;
• a decoding unit coupled to the mask identifier module, the decoding unit operable to generate an unmasked codeword by applying a portion the mask to the codeword;
• wherein, the portion of the mask corresponds with a location of the codeword in the 2D symbol;
• wherein, the codeword comprises multiple codeword bits and the portion of the mask comprises multiple mask bits;
• an erasure identifier module coupled to the decoding unit, the erasure identifier module operable to compare the unmasked codeword with the portion of the mask to determine whether the codeword is the erasure.

A system for marking a codeword as an erasure in a Quick Response code (QR code) captured by a bar code reader, the QR code having data that is encoded with a scrambling mask, the method, comprising:

• means for identifying the scrambling mask used for encoding the data in the codeword;
• wherein, a location of the codeword in the QR code corresponds with a portion of the mask and the codeword comprises multiple codeword bits and the portion of the scrambling mask comprises multiple mask bits;
• means for generating an unscrambled codeword by performing a logical exclusive-OR operation between each of the multiple codeword bits and each of the multiple mask bits;
• means for generating a reference matrix by applying the scrambling mask to a uniform matrix;
• wherein, the uniform matrix comprises a set of same-valued bits and the reference matrix comprises multiple reference bits;
• and
• means for comparing the unscrambled codeword with the reference matrix to determine whether the codeword is the erasure.