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Евтихиев, Николай Николаевич

Организационные подразделения

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Евтихиев

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Николай Николаевич

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Теперь показываю 1 - 10 из 37

Только метаданные
Asymmetric image optical encryption under spatially incoherent illumination
(2020) Cheremkhin, P. A.; Evtikhiev, N. N.; Krasnov, V. V.; Rodin, V. G.; Shifrina, A. V.; Starikov, R. S.; Черёмхин, Павел Аркадьевич; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Шифрина, Анна Владимировна; Стариков, Ростислав Сергеевич
In this paper new method of asymmetric optical encryption is presented. It is based on the double encryption using spatially incoherent illumination: to obtain a ciphertext a plaintext is encoded twice, first time by sender, second time-by recipient. This way no exchange of encryption keys is required. Two variants of this method were analyzed: one in which both encryption procedures are implemented optically and another one in which the first operation is done optically and the second one-numerically. Both variants were numerically simulated and the latter one was implemented optically. Results of numerical and optical experiments demonstrate high quality of decrypted images (decoding error 0.19), thus confirming usability of proposed method.
Только метаданные
QR-code optical encryption in the scheme with spatially incoherent illumination based on two micromirror light modulators
(2020) Evtikhiev, N. N.; Krasnov, V. V.; Kuzmin, I. D.; Molodtsov, D. Y.; Rodin, V. G.; Starikov, R. S.; Cheremkhin, P. A.; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич; Черёмхин, Павел Аркадьевич
An optical encryption scheme with spatially incoherent illumination based on two micromirror light modulators has been experimentally implemented for the first time. Currently, such modulators arc the fastest tools for spatio-temporal light modulation; their high frame rates provide possibilities for developing optical encryption systems with a bandwidth of several gigabites per second.
Только метаданные
Fast increase of quality of optically reconstructed images in digital holography
(2020) Cheremkhin, P. A.; Evtikhiev, N. N.; Krasnov, V. V.; Rodin, V. G.; Черёмхин, Павел Аркадьевич; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич
© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Digital holography is technique for registering of 2D- and 3D-scenes characteristics: amplitude or phase images of object, roughness, and etc. Numerical reconstruction allows fast images recovery. However high quality optical reconstruction is not so fast due to the hologram transferring to the spatial light modulator (SLM), hologram digital preprocessing, SLM calibration, and etc. In this work we analyzed possibilities of fast processing of the holograms for increasing of quality of optically reconstructed images. Amplitude type holograms were registered and images were optically reconstructed using phase liquid crystal SLM. Various techniques of improvement of reconstruction quality were used.
Только метаданные
Application of a Digital Micromirror Device for Optical Encryption with Time Integration
(2020) Evtikhiev, N. N.; Krasnov, V. V.; Molodtsov, D. Y.; Rodin, V. G.; Starikov, R. S.; Cheremkhin, P. A.; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич; Черёмхин, Павел Аркадьевич
© 2020, Allerton Press, Inc.Abstract: The possibility of using a digital micromirror device (DMD) for implementing the optical encryption with time integration in quasimonochromatic spatially incoherent light is considered. An experimental setup for optical registration of image to be encrypted on a digital camera is presented. Images containing text and graphic information are encrypted and successfully decrypted using inverse filtering. The use of time integration in optical encryption makes it possible to reduce the noise caused by binarization of holograms display on DMD that contains encryption keys and to increase the diffraction efficiency of the encryption process.
Только метаданные
High-speed implementation of holographic and diffraction elements using digital micromirror devices
(2020) Evtikhiev, N. N.; Zlokazov, E. Y.; Krasnov, V. V.; Rodin, V. G.; Starikov, R. S.; Cheremkhin, P. A.; Евтихиев, Николай Николаевич; Злоказов, Евгений Юрьевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич; Черёмхин, Павел Аркадьевич
© 2020 Kvantovaya Elektronika and Turpion Ltd.We report the results of simulations and experiments on the formation of light distributions by holograms and diffraction elements displayed by digital micromirror devices. Examples of successful experiments on the implementation of optical-digital systems based on them are demonstrated.
Только метаданные
The influence of additional phase modulation of an amplitude liquid crystal stlm on the image recognition characteristics in the invariant optical digital correlator
(2019) Goncharov, D. S.; Evtikhiev, N. N.; Krasnov, V. V.; Ponomarev, N. M.; Starikov, R. S.; Евтихиев, Николай Николаевич; Стариков, Ростислав Сергеевич
© 2019, Institution of Russian Academy of Sciences. All rights reserved.We present the results of measurements of additional phase modulation characteristics of a serial amplitude liquid crystal spatial light modulator HoloEye LC 2002. It is found in which way the phase shift of the liquid crystal spatial light modulator depends on the applied signal. The mathematical simulation of the performance of an invariant diffractive optical-digital correlator based on a liquid crystal spatial light modulator with the amplitude-dependent phase shift is carried out using previously measured data. The correlation filters used in the work are an optimal tradeoff maximum average correlation height filter and a minimum noise and correlation energy optical correlation filter. A method for correlation filters optimization was proposed to compensate for the recognition error caused by the presence of the additional phase modulation. In some cases, the optimization allows one not only to compensate for the recognition error, but also to reduce it.
Только метаданные
Measurement of Modulation of the Phase Liquid-Crystal Light Modulator Santec SLM-200 and Analysis of Its Applicability for the Reconstruction of Images from Diffraction Elements
(2021) Evtikhiev, N. N.; Krasnov, V. V.; Ryabcev, I. P.; Rodin, V. G.; Starikov, R. S.; Cheremkhin, P. A.; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич; Черёмхин, Павел Аркадьевич
© 2021, Springer Science+Business Media, LLC, part of Springer Nature.We consider the problem of achieving high stability and linearity of phase liquid-crystal space-time light modulators, which are widely used for optical reconstruction of diffractive optical elements, including holograms. Modern high-resolution space-time light modulators one uses a digital signal addressing circuit, which leads to phase shift fluctuations during the frame. For the modern high-resolution phase liquid crystal space-time light modulator Santec SLM-200, the dependences of the phase shift on the level of the addressed signal and time from the beginning of the frame have been measured. Using the Santec SLM-200 light modulator, optical reconstruction of images from diffractive elements of different types was performed, their diffraction efficiency and the quality of the reconstructed images were evaluated. The values of the diffraction efficiency were obtained in the range of 3–10%; a sharp drop in the brightness of the reconstructed images is observed with distance from the optical axis in the plane of reconstruction.
Только метаданные
Shot Noise and Fixed-Pattern Noise Effects on Digital Hologram Reconstruction
(2021) Cheremkhin, P. A.; Evtikhiev, N. N.; Krasnov, V. V.; Rodin, V. G.; Starikov, R. S.; Черёмхин, Павел Аркадьевич; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич
© 2020Digital holography allows registering and reconstructing information about 3D objects and 3D scenes. There are several limitations related to reconstructed image quality: speckle noise, twin images, zero order, light (shot noise) and dark temporal noise, camera fixed-pattern noise (spatial noise), dynamic range, and quantization noise. These restrictions determine the maximum possible signal-to-noise ratio (SNR) of digital holograms and reconstructed images. This work is concerned with studying the effect of a digital camera's main noise components on hologram reconstruction. Analytical equations for estimation of SNR of reconstructed amplitude image were obtained. They relate to a number of values: shot noise, dark temporal noise, fixed-pattern noise, camera's dynamic range, quantization noise, reference and object beam intensities, and the ratio between the object area and the entire reconstructed field. The resulting equation was tested experimentally using digital holograms of diffusely scattering objects. Characteristics of different types of CCD and CMOS cameras were used: digital single-lens reflex (DSLR), scientific, industrial, and video surveillance cameras. The effect of the camera noise on the phase image reconstruction was also estimated. The resulting equations make it possible to estimate the camera noise's effect on the reconstructed images before the experiments were conducted. As a result, the illumination value, exposure time, object size, and other experimental conditions can be pre-selected to reduce the noise in holograms used in metrological and infrared applications and optical encryption.
Только метаданные
Comparative analysis of off-axis digital hologram binarization by error diffusion
(2021) Cheremkhin, P. A.; Kurbatova, E. A.; Evtikhiev, N. N.; Krasnov, V. V.; Rodin, V. G.; Starikov, R. S.; Черёмхин, Павел Аркадьевич; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Стариков, Ростислав Сергеевич
A digital micromirror device (DMD) provides 2D- and 3D-scene reconstruction by displaying diffractive and holographic optical elements. The highest frame rates (tens of thousands of Hz) can be achieved if the displayed optical elements are binarized. Except for DMD applications, hologram binarization is useful for display creation, image encryption, information compression and storage, fast 3D printing, etc. Error diffusion is one of the most qualitative implementations of hologram binarization. In this paper, three group's weighting matrices of error diffusion are analyzed: 16 standard, eight dot and six diagonal matrices. Thus, 30 error diffusion methods were used for optically recorded off-axis digital hologram binarization. The quality of the image reconstruction from the binarized holograms was compared. Direct applications of error diffusion with large weighting matrices and dot diffusion provide the highest reconstruction quality. Seven metrics were used as the error diffusion threshold. Twelve bypass directions of error diffusion were analyzed. In addition, the joint application of Otsu threshold and complex bypass directions allows us to improve the quality of hologram binarization by 15%.
Только метаданные
Lensless optical encryption with speckle-noise suppression and QR codes
(2021) Cheremkhin, P. A.; Evtikhiev, N. N.; Krasnov, V. V.; Rodin, V. G.; Ryabcev, I. P.; Shifrina, A. V.; Starikov, R. S.; Черёмхин, Павел Аркадьевич; Евтихиев, Николай Николаевич; Родин, Владислав Геннадьевич; Шифрина, Анна Владимировна; Стариков, Ростислав Сергеевич
© 2021 Optical Society of AmericaThe majority of contemporary optical encryption techniques use coherent illumination and suffer from speckle-noise pollution, which severely limits their applicability even when information encoded into special “containers” such as a QR code. Spatially incoherent encryption does not have this drawback, but it suffers from reduced encryption strength due to formation of an unobscured image right on top of the encrypted one by undiffracted light from the encoding diffraction optical element (DOE) in axial configuration. We present a new lensless encryption scheme, experimentally implemented with two liquid crystal spatial light modulators, that does not have this disadvantage because of a special encoding DOE design, which forms desired light distribution in the photosensor plane under spherically diverging illumination without a converging lens. Results of optical experiments on encryption of QR codes and successful information retrieval from decoded images are presented. Conducted analysis of encryption strength demonstrates sufficiently high key sensitivity and large enough key space to resist any brute force attacks.