Latent Scrambled Image / Invisible Personal Information
An image formed by strokes or raster elements that are printed in the background pattern or portrait so that the image is not visible to the naked eye. The image is pre-fragmented and encoded using special algorithms. As a rule, a photograph encodes the owner's personal data (e.g. name, surname, serial number), forming invisible personal information (IPI).
A latent scrambled image is visualized and decoded with the use of decoding devices (filters for visualizing latent scrambled images) or special software.
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Fig. 1. Ecuador. Diplomatic passport issued in 2015:
a — front endpaper. Paper substrate; b — the same. Background pattern containing a latent scrambled image. Rainbow printing. Viewed at a right angle of observation and illumination; c — the same. Latent scrambled image № 1 visualized with a filter; d — the same. Latent scrambled image № 2 visualized with a filter; e — the same. Back endpaper. Paper substrate; f — the same. Microprinting in the form of wavy lines containing a latent scrambled image. Intaglio printing. Viewed at a right angle of observation and illumination; g — the same. Latent scrambled image visualized with a filter
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Fig. 2. Bulgaria. Passport issued in 2010:
a — data page. Paper substrate; b — the same. Invisible personal information (IPI) on the holder's portrait. Inkjet printer. Decoded and visualized with the Regula Forensic Studio software