Design of high capacity 3D print codes with visual cues aiming for robustness to the PS channel and external distortions

Abstract

Adding high-density information to printed materials enables and improves interesting hardcopy document applications involving security, authentication, physical-electronic round tripping, item-level tagging, and consumer/product interaction. This investigation of robust and high capacity print codes aims to maximize information payload in a given printed page area, subject to robustness to channel errors including distortions introduced by the printing and scanning processes and also due to the usual degradations introduced by user manipulation of printed documents. The novel approach includes statistical print-and-scan channel characterization, designing of robust segmentation using visual cues, unsupervised Bayesian color classification with expectation-maximization algorithm for parameters estimation of a mixture of Gaussians model and design of error correction codes. Results illustrate the performance evaluated under real channel and distortions conditions. High payload is achieved with sufficient robustness to distortions resulting of regular office hardcopy document handling: printand-scan channel and user manipulation.

Document imaging security and forensics ecosystem considerations

“…Villán et al [16] provide several multilevel (grayscale or color) barcode approaches providing up to 2400 bytes/in 2 information density. Limiting the color set to the primary printing colors -cyan, magenta and yellow, or CMY -and using a variety of errorcorrecting code (ECC) approaches, Mayer et al provide a large footprint information-containing 3D print code [17].…”

“…Structural pre-compensation (StrPC) is used to optimize the relative size of the ICMs over the background. We have used StrPC to anticipate the "module gain" of 2D barcodes over their background [18] and to reduce the deleterious effect on of the spread of inkjetted ink into the substrate -which otherwise creates color overlap on the boundaries of color modules [17]. The extent of StrPC needed depends on the ink spread into/on the surface of the substrate.…”