3-dimensional dot code

摘要

A 3-D dot code is embedded in a printed medium using an embedder (15) that embeds data directly into the halftone dots of a selected file that is ready for printing. An extractor (17) extracts the embedded bits by scanning the printed medium and then interprets the embedded data. A bleed-through elimination module in the extractor is able to eliminate adverse affects on the scanned input of the embedded data caused by bleed-through from the print on the opposite side of the page. The extractor may also include a module that compensates for a misaligned scanned input by automatically detecting the rotation and translation, and then registering the image so that the upper-left corner is located in a certain position. This operation expedites subsequent data retrieval, in which data is read by block matching.