Transformed phase mask and photoanisotropic material in optical correlators applied for security verification

Muravsky, Leonid I.; Voronyak, Taras I.; Fitio, Volodymyr

doi:10.1117/1.602058

Cited by 12 publications

(11 citation statements)

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“…In this case, not only peak intensities, but also vector distances between peaks can be regarded as identification criteria. 6,7 Let us consider briefly the linear and nonlinear models of such the RHM's producing and identification. …”

Section: Conditions Of Master Hologram Recording and Reconstructionmentioning

confidence: 99%

“…The part of correlation response covering the first diffraction order area is used for creation of an identification feature vector and its comparison with a reference feature vector. 6 The results of reconstruction of master holograms and RHMs are represented in Fig. 6 and Fig.…”

Section: Reconstruction and Analysis Of Rhms And Refelecting Master Hmentioning

confidence: 99%

“…[1][2][3] The optical methods and systems possess large possibilities to resist the counterfeiting due to the parallel encodingdecoding of large amount of information and, in particular, 2D and 3D arrays. The techniques utilizing random phase masks simultaneously with fingerprints, [2][3][4][5][6][7] in particular, the security verification technique 2,4 and the method for optical protection and identification of documents, 6,7 are very perspective among optical security technologies.…”

Section: Introductionmentioning

confidence: 99%

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The new approach to identification of film reflecting holographic marks

Kostyukevych¹

2011

Semicond. Phys. Quantum Electron. Optoelectron.

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Abstract. The new approach for creation of film reflecting holographic marks for optical security is proposed. Such marks are replicas of a reflecting master hologram recorded on a chalcogenide glass layer. To receive the master hologram, the joint power spectrum of a reference phase mask and an input phase mask or a transformed phase mask is produced at the plane of the hologram writing and is modulated by an inclined laser beam. If an inclined laser beam illuminates the replica recorded on a flexible substrate, phase noise including speckle noise is eliminated because the hologram carrier frequency exceeds greatly the limiting frequency of the phase noise power spectrum. Experimental results have shown the principal possibility to produce the high performance film reflecting holographic marks for security applications. The proposed approach can be combined with technologies for fabrication of rainbow holograms. In this case, the received rainbow holograms are the reflecting holographic marks simultaneously. Therefore, they can be verified not only visually, but also by means of automatic identification.

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Section: Conditions Of Master Hologram Recording and Reconstructionmentioning

confidence: 99%

Section: Reconstruction and Analysis Of Rhms And Refelecting Master Hmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The new approach to identification of film reflecting holographic marks

Kostyukevych¹

2011

Semicond. Phys. Quantum Electron. Optoelectron.

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“…[4][5][6][7][8] We have created the optical/digital device (ODD) for the identification of credit cards [8][9][10][11][12] . The well-known security verification technique 1-3 is suitable for this purpose.…”

Section: Introductionmentioning

confidence: 99%

<title>Geometrical features of transformed phase masks in the optical/digital device for identification of credit cards</title>

et al. 2002

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The new method for identification of optical marks containing transformed phase masks (TPMs) is considered. A TPM placed in an optical correlator produces several sharp correlation peaks on its output. We choose the distances between peaks as basic geometrical features of a TPM. The increase of quantity of basic features leads to the increase of security level of documents and valuable papers. However, the amount of such features is limited and is depending from many factors. We picked the probability of false identification of the nearest feature as the criterion of separation of features on independent classes. The optical/digital device for identification of credit cards based on a joint transform correlator architecture was used for the study of TPMs. To estimate the law of distribution of basic features inherent to the same class, we carried out experiments with the series of TPMs. We have shown, that the additional features allow to increase the number of basic features, separated on different classes. These experiments also have allowed to estimate the error of features measurements.

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“…Optical encryption have the added property that a large amount of data can be stored or retrieved in parallel and at high speed. The first to be used were techniques related to analog en cryption methods based on different correlation architectures [7,8]. These setups can be considered as the basis for the design of real-time optical security devices.…”

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confidence: 99%

Fully digital encryption technique

Arizaga

Henao²,

Torroba

2003

Optics Communications

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We propose an alternative fully digital encryption technique based on using the Fourier transform of the original object to be processed and a speckled reference wave as encryption mask. Once encrypted, the Fourier transform spectrum of the object is holographically stored. The original data recovering is performed by digital reconstruction using the same encryption mask, which is also holographically stored. Quality of reconstructed data is evaluated as a function of the sensed encrypted data. Computer simulations and experimental results are presented to demonstrate the method. © 2003 Elsevier Science B.V. All rights reserved.In recent years, several proposals on informa tion security using optical techniques were published [1 6]. Optical encryption have the added property that a large amount of data can be stored or retrieved in parallel and at high speed. The first to be used were techniques related to analog en cryption methods based on different correlation architectures [7,8]. These setups can be considered as the basis for the design of real-time optical security devices. Most optical correlators use 2-D input images and are designed around a 2-D op * Corresponding author. Fax: +54-221-4712771. E mail address: robertot@ciop.unlp.edu.ar (R. Torroba).tical processing architecture. However, the presence of complex or expensive elements complicates the creation of simple and low-priced devices of this type. These correlators can be used for instance to secure entry systems that identify individuals for access to a restricted area. In security systems, the image, such as a picture of a face or a fingerprint, is used for the same purpose. They include memory units for storing key code images that are used to verify the authenticity of the input image. It is impossible to verify the encoded documents without knowing the key mask that have been used in the encoding. Furthermore, key codes have to be unique to be a full-proof, reliable ac curate, ready to implement as well as to meet the goal of putting the counterfeits and frauds to a complete halt. The systems are also integrated to a network. If the memory units are stolen or if important data are intercepted by monitoring the transmission line in the network, however, an unauthorized person can extract vital information easily. It is becoming increasingly simple to reproduce the input data of the security system. Therefore, data protection has become necessary. The most preferred method is that of double random phase encryption [9]. In the encryption process input data (positive real-valued image) is multiplied by a random phase function, then Fourier transformed and finally multiplied by another random phase function. We can obtain a decrypted image by first multiplying by the com plex-conjugate of the second encoding phase function and taking a Fourier transform. Many related contributions were generated, including the use of a Joint transform correlator (JTC) [10] or optical arrangements using photorefractive crystals [11]. The content of the proposals was...

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Transformed phase mask and photoanisotropic material in optical correlators applied for security verification

Cited by 12 publications

References 9 publications

The new approach to identification of film reflecting holographic marks

The new approach to identification of film reflecting holographic marks

<title>Geometrical features of transformed phase masks in the optical/digital device for identification of credit cards</title>

Fully digital encryption technique

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