&lt;title&gt;Multilevel computer-generated holograms for reconstructing 3D images in combined optical-digital security devices&lt;/title&gt;

Girnyk, Vladimir I.; Kostyukevych, Sergey A.; Kononov, Alexandr V.; Borisov, Ilya S.

doi:10.1117/12.462717

Cited by 8 publications

(2 citation statements)

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“…With the purpose to get more constant values of the amplitude complex field in the hologram plane, we proposed to supplement this algorithm with an additional emphasis of the object amplitude [15][16][17][18][19].…”

Section: Synthesis Of the Kinoformmentioning

confidence: 99%

Kinoform synthesis as an improved method to form a concealed image in optical security devices

Braginets¹

2006

Semicond. phys. quantum electron. optoelectron.

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It is well known that one of the basic functions of security holograms is the maximal complication of their non-authorized reproduction, in other wordscounterfeiting. To solve the problem, concealed images that can be observed only under special conditions are placed into a structure of the hologram. A popular way to place concealed image in Diffractive Optically Variable Image Device (DOVID) is integration into DOVID's structure of a Concealed Laser-Readable Image (CLRI). Traditionally CLRI is a 2D Computer-Generated Hologram (2D CGH), which is a digitized Interference Fringe Data (IFD) structure, computed under the scheme of Fourierhologram synthesis. Such hologram provides inspection of the second level with portable laser reading devices. While it is being read, two (+/-1 order of diffraction) identical images are formed. It is very interesting to achieve a CGH, which restores the image only in one diffractive order or two different images in +1 and-1 orders of diffraction.

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Section: Synthesis Of the Kinoformmentioning

confidence: 99%

Kinoform synthesis as an improved method to form a concealed image in optical security devices

Braginets¹

2006

Semicond. phys. quantum electron. optoelectron.

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“…CGRH can entirely substitute the optical part in Combigram TM , because it supposes wider possibilities for object representation and also allows more accurate interaction with the remaining digital part, so we obtain Polygram. The paper [2] was devoted to the first trial fabrication of the separate CGRH using chalcogenide layers.…”

Section: Destination Of Cgrhsmentioning

confidence: 99%

Investigation of synthesis peculiarities inherent to computer-generated rainbow holograms of 3D images

Girnyk¹

2002

Semicond. Phys. Quantum Electron. Optoelectron.

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This work deals with Computer-Generated Rainbow Holograms (CGRHs), which can restore the 3D images under white light. They are devoted to include in Diffractive Optically Variable Image Devices (DOVIDs) that are currently widely used for security needs. CGRHs prevent counterfeiting due to the complexity of recreation, on the one hand, and allow the simple identification at the first (visual) level of verification, on the other hand. To record it, the Electron Beam Lithography (EBL) is used. As recently proved, this method is a most promising for multi-level optical-digital security devices using chalcogenide glasses as resists. The CGRH computation process is conventionally divided by two parts: synthesizing and recording. On the synthesis stage, firstly, the geometrical and optical constants of recording scheme are determined; secondly, the basic parameters accounting for discretization of Interferogram Data (ID) in hologram plane are defined and, finally, the calculation of the ID the array of Bipolar Intensity (BI) values is carried out. This calculation is performed separately in each independent horizontal slice of object space and hologram plane. On the recording stage, suitable quantization parameters are chosen and transformation of ID into the multilevel rectangle data appropriate for EBL is accomplished. The investigations on optimization of synthesis and recording of the multilevel CGRHs of 3D images integrated in Polygrams are presented here. So the rules for definition of the appropriate discretization parameters were finding out. Advantages of using non-linear quantization that implies condensing of quantization levels near the BI zero were explored. The random deviation of location and direction of elemental hybrid radiating area was applied. Practical applications of the method developed were made using chalcogenide semiconductors of various AsS -Se compositions.

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MIDV-Holo: A Dataset for ID Document Hologram Detection in a Video Stream

Koliaskina,

Emelianova,

Tropin

et al. 2023

Lecture Notes in Computer Science

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<title>Multilevel computer-generated holograms for reconstructing 3D images in combined optical-digital security devices</title>

Cited by 8 publications

References 1 publication

Kinoform synthesis as an improved method to form a concealed image in optical security devices

Kinoform synthesis as an improved method to form a concealed image in optical security devices

Investigation of synthesis peculiarities inherent to computer-generated rainbow holograms of 3D images

MIDV-Holo: A Dataset for ID Document Hologram Detection in a Video Stream

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