Paper Widgets: Distributed “smarts” for Paper Documents with Human-readability
چکیده
Traditional 1D and 2D barcodes provide high data density, but they are visually jarring and require isolated white margins for placement. In this work, we introduce new machine-readable “smarts” for paper documents, called paper widgets. Unlike barcodes, paper widgets have very small footprint (fraction of a sq. cm.) and a human-readable component that provides visual meaning. They can also be placed and extracted from any position on the paper document, for instance, right beside contents of interest. This paper describes in detail, the design and implementation of the encoding, extraction, and decoding of paper widgets. Constrained coding techniques are used to combat the print-scan intersymbol interference (ISI), while Gabor filtering and adaptive thresholding help extract widget regions from a scanned document. Experimental evaluations have revealed that paper widgets can be decoded from printing/scanning operations with near-100% accuracy.