Automated Optimization of Void Pantograph Settings
Abstract:Void pantographs (VPs) have been an important part of the security printing toolkit for several decades. When crafted for a specific printing technology, VPs provide an almost “magical” effect—they are nearly invisible in the original print and then stand out strikingly when they are copied. However, this effect comes at an expense—VPs have historically been designed only for a specific printing technology, and so cannot be extended to a mobile-printing world, where the VP needs to be supported by a wide range of printers.
In this paper, we describe an automated process for optimizing the VP settings. These are the background and foreground pattern used in the VP—the background “disappears” when copied and the foreground “bolds”. VP test sheets are created using the ranges of background and foreground settings necessary to guarantee identification of at least one “readable” pair of settings. This can be automated by writing the VP as a readable mark—for example, a barcode that can be read (or not read) by a barcode reader; text that can be read (or not read) by an optical character recognition (OCR) engine; or even a face that can be recognized by a face recognition engine. The successful VPs will not be readable (using camera images to prevent a “copying” effect) when originally printed but accurately readable (using a camera) after a single copy, or print-scan, cycle.
Document Type: Research Article
Publication date: 2011-01-01
For more than 30 years, IS&T's series of digital printing conferences have been the leading forum for discussion of advances and new directions in 2D and 3D printing technologies. A comprehensive, industry-wide conference that brings together industry and academia, this meeting includes all aspects of the hardware, materials, software, images, and applications associated with digital printing systems?particularly those involved with additive manufacturing and fabrication?including bio-printing, printed electronics, page-wide, drop-on-demand, desktop and continuous ink jet, toner-based systems, and production digital printing, as well as the engineering capability, optimization, and science involved in these fields. In 2016, the conference changed its name formally to Printing for Fabrication to better reflect the content of the meeting and the evolving technology of printing.
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