Security hologram

Holograms are classified into different types with reference to the degree of level of optical security incorporated in them during the process of master origination.

[citation needed] The term "hologram" has taken on a secondary meaning due to the widespread use of a multi-layer image on credit cards and driver licenses.

This type of "hologram" consists of two or more images stacked in such a way that each is alternately visible depending upon the angle of perspective of the viewer.

These holograms have a maximum resolution of 10 micrometers per optical element and are produced on specialized machines making forgery difficult and expensive.

[citation needed] This technique requires development of various algorithms for designing optical elements that shapes scattered radiation patterns.

These are sets of thin lines of a complicated geometry (guilloché patterns) drawn with high resolution.

Computing CLR images is a complicated mathematical task that involves solving ill-posed problems.

[jargon] More recently, novel computer-generated holograms have been proposed working with structured light carrying phase singularities.

[3] Such optical elements further improve the security level, since the encoded information only appears when the input illumination is endowed with the correct intensity and phase distribution.

[citation needed] 2D/3D hologram masters are developed in 2D/3D master shooting lab that incorporates highly sensitive machines and advanced equipment such as microprocessor-controlled automatic positioning equipment, optical table, He-Cd laser, laser power controller, silver coatings and other related technologies.

When synthesized by a computer, they may include microtexts, hidden images, and other security features, yielding attractive, high-security holograms.[promotion?]