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Avtometriya

2022 year, number 3

1.
INVESTIGATION OF THE TEMPERATURE SHIFT OF THE WAVELENGTH OF A SEMICONDUCTOR LASER DIODE IN A DOPPLER ANEMOMETER

V.A. Pavlov, G.V. Bakakin, V.V. Rakhmanov, S.V. Dvoynishnikov
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: wavelength shift, semiconductor laser diode, laser Doppler anemometer

Abstract >>
The temperature stability of the laser wavelength is an important characteristic of a laser Doppler anemometer with chromatic channel separation. In this work, experimental studies of the wavelength shift of a semiconductor laser diode by 660 nm as a function of temperature and laser radiation power are carried out. It is established that the temperature drift of the wavelength lies within 0.2 nm/°C. It is shown that the use of semiconductor diodes of this type in laser Doppler anemometers with chromatic channel separation is possible, but requires careful selection of optical filters.



2.
ANALYSIS OF SELF-CALIBRATION ALGORITHMS IN OPTICAL ANGULAR ENCODERS

V.P. Kiryanov1, A.D. Petuhov1, A.V. Kiryanov1,2
1Institute of Automation and Electrometry, Sibirian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: goniometry, angular encoders, self-calibration algorithms, conversion error, simulation modeling

Abstract >>
To date, two basic types of algorithms for self-calibration of optical angular encoders have been developed in precision goniometry, differing in regular and irregular localization of the reading heads used in their structure. The analysis of the precision values of such encoders revealed the presence of special features not provided for by the theory, which stimulated the execution of experiments on modeling the expected values of such algorithms. The simulation model of optical angular encoders proposed by the authors of the article based on a two-dimensional data array makes it possible to identify the methodological error of the measurement algorithm used with sufficient accuracy for practice by determining the residual contribution of the distorting function to the final measurement error. In addition, it allows us to identify the characteristic features of calibration curves formed on the basis of methods with uniform or nonuniform localization of the reading heads. The simulation results show that self-calibration methods based on regular localization of the reading heads allow for higher measurement accuracy compared to methods based on the use of irregular localization.



3.
STUDY AND FABRICATION OF PHOTONIC INTEGRATED CIRCUITS BASED ON K-8 GLASS FOR FUNCTIONAL DATA PROCESSING AT A WAVELENGTH OF 1550 NM

M.M. Vekshin, V.A. Nikitin, N.A. Yakovenko
Kuban State University, Krasnodar, Russia
Keywords: Integrated optics, ion exchange in glass

Abstract >>
On the base of a physico-mathematical model of ion exchange and field-assisted ion migration in glasses, with the use of a beam propagation method and mode analysis, simulations with subsequent fabrication of photonic integrated circuits in K-8 domestic optical glass operating at a wavelength of 1550 nm, have been performed. The main passive waveguide components, including single-mode waveguide dividers of optical signals, directional couplers, polarization converters, etc., have been fabricated and studied. Multichannel waveguide splitters of optical beams and matrices (512 × 512 pcs) of long-focal plane-convex microlenses for Shack-Hartmann wavefront sensors have been created by the method of field-assisted ion migration in glass substrates.



4.
TELECENTRIC F-THETA LENSES FOR SCANNING SYSTEMS

T.N. Khatsevich, A.I. Bodnarchuk
Siberian State University of Geosystems and Technologies, Novosibirsk, Russia
Keywords: F-Theta lens, telecentric trace, distortion, scan path, deviations from linearity and straightness

Abstract >>
A geometric model of an ideal F-Theta lens is proposed. The trajectory of the scanning spot movement along the scanning working field is calculated. The results of the study of several foreign lenses and lenses proposed by the authors in terms of deviations from the linear law and from the straightness of the trajectory are presented. The results of calculating a number of lenses for scanning working fields from 35x35 to 400x400 mm are reported.



5.
DETERMINATION OF THE MODULATION TRANSFER FUNCTION OF INFRARED OBJECTIVES

V.V. Vasiliev, A.V. Vishnyakov, G.Yu. Sidorov, V.A. Stuchinsky
Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: characterization of IR objectives, mercury-cadmium-tellurium, Line Spread Function, Modulation Transfer Function, 2D IR focal-plane-array detectors

Abstract >>
A method for determining the modulation transfer function (MTF) of infrared (IR) objectives is proposed. With the help of an objective under test, the image of a narrow exit slit of a monochromator used as a radiation source and tuned to a certain wavelength is focused in the form of a long narrow strip onto a cold metal screen with a fine aperture slit. Such a slit aperture, used instead of a pinhole aperture, allowed us to increase the useful signal and employ the exit slit of the monochromator as a radiation source. Behind the screen, instead of a small-area IR detector previously used in similar characterization studies of IR objectives, an apertured 2D IR FPA detector was used. With the help of 320×256 mid-wave IR (MWIR) and long-wave IR (LWIR) focal-plane-array detectors based on epitaxially grown mercury-cadmium-tellurium films, the Line Spread Function and MTF of MWIR and LWIR objectives were measured. The experimental data obtained were compared to the calculated diffraction-limited MTF of the tested objectives.



6.
IMPLEMENTATION OF A WAVEFRONT-SENSING ALGORITHM WITH TWO-CHANNEL MOIRÉ DEFLECTOMETRY AND MATLAB GRAPHIC USER INTERFACE

M. Dashti1, S. Rasouli2,3
1Islamic Azad University, Zanjan, Iran
2Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
3Optics Research Center, Zanjan, Iran
Keywords: Wavefront sensor, MATLAB program, MoirГ© fringes, Wavefront aberrations

Abstract >>
Experimental setups of a two-channel wavefront sensor (WFS) based on moiré deflectometry have been proposed and developed in recent years. The capabilities of this WFS have been tested in the atmospheric turbulence measurements. Like other WFSs, it can be used in various areas. Therefore, we have developed a MATLAB graphical user interface program to allow any user to easily make use it. This program takes simultaneous horizontal and vertical moiré patterns as input data and reconstructs the corresponding wavefront map and its aberration values. The algorithm of the process is explained step by step in this paper. For a typical input moiré pattern, the results such as the wavefront shape and corresponding first ten Zernike coefficients are calculated and are shown as outputs of the software. In addition, there is a special part in the program for atmospheric turbulence applications that calculates the strength amount of the turbulence, Cn2 and the temporal evolution of the angle of arrival.



7.
APPLICATION OF NEURAL NETWORKS FOR DIFFERENTIAL DIAGNOSIS OF PULMONARY PATHOLOGIES BASED ON X-RAY IMAGES

S.M. Borzov1, A.V. Karpov2, O.I. Potaturkin1, A.O. Hadziev2
1Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Federal State Budgetary Institution "Novosibirsk Tuberculosis Research Institute", Ministry of Health of the Russian Federation, Novosibirsk, Russia
Keywords: digital image processing, classification, neural network technologies, intelligent systems, diagnostics of lung diseases

Abstract >>
The goal is to study the possibility of creating intelligent automated systems for differential diagnosis of pulmonary diseases based on the identification of pathological structures in X-ray images of thoracic cavity organs using neural network technologies. A brief analysis of modern diagnostic techniques is presented, and a description of the proposed algorithm for determining the type of lung tissue pathologies used in the visual analysis of X-ray images and based on the identification of the main radiological syndromes, as well as on the evaluation of the quantitative characteristics of differential X-ray diagnostics, is given. By the example of classification of radiographs of healthy and tuberculosis patients, the effectiveness of using neural network technologies in the computer diagnosis of lung diseases is demonstrated. The studies are carried out using a publicly available database of X-ray images of thoracic cavity organs containing 3,500 images of healthy people and the same number of sick people images.



8.
DETERMINATION OF THE NUMBER OF EARS IN IMAGES OF WHEAT FIELDS BY METHODS COMPUTER VISION

S. N. Tereshchenko, A. L. Osipov, E. D. Moiseeva
Novosibirsk State University of Economics and Management, Novosibirsk, Russia
Keywords: neural networks, artificial intelligence, wheat, ears, productivity, deep learning, augmentation, object detection

Abstract >>
The neural network technology is used to accurately calculate the number of wheat ears from photographs of a wheat field. The methods of deep learning of convolutional neural networks in interaction with the transfer learning methodology are used. With the help of the EfficientDet architecture, the neural network is trained, which allows the number of wheat ears to be determined from graphical images with accuracy of 0.88012 on a sample using the F1-score metric with a threshold value of 0.6 (the coincidence of the predicted markup and the actual one).



9.
INVESTIGATION OF THE HYPERSPECTRAL DATA CLASSIFICATION EFFICIENCY UNDER CONSTRAINTS ON THE BIT DEPTH OF QUANTIZATION, NUMBER OF SPECTRAL CHANNELS, AND SPATIAL RESOLUTION

V.V. Shipko1, S.M. Borzov2
1Military Educational Scientific Center of the Air Force "Air Force Academy named after Prof. N.E. Zhukovsky and Yu.A. Gagarin,", Voronezh, Russia
2Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: hyperspectral images, classification, quantization, spatial resolution, spectral channels

Abstract >>
The possibility of creating a fast-response framing hyperspectrometer functioning as a conventional camera is studied. It is considered how much the classification accuracy will have to be sacrificed for the implementation of the idea of creating a compact and easy-to-use hyperspectral camera with rapidly tunable parameters. Experimental studies of the classification accuracy depending on the number and method of selection of spectral channels, spatial resolution, and bit depth of quantization of the signal brightness are carried out on a test hyperspectral image. It is shown that, though the resulting accuracy decreases, it still remains acceptable for a wide range of practical tasks.



10.
PROCESSING AND ANALYSIS OF OPTICAL NON-COORDINATE INFORMATION ON OBJEECTS UNDER OBSERVATION

A.O. Zhukov1,2, A.I. Gladyshev3, M.E. Prokhorov4, A.A. Zaverzaev5
1Expert-Analytical Center, Moscow, Russia
2Institute of Astronomy, Russian Academy of Sciences
3Sector of applied research of RAS Presidium, Moscow, Russia
4Sternberg Astronomical Institute, Moscow State University, Moscow, Russia
5Joint-Stock Company "Special Design Bureau of the Moscow Power Engineering Institute", Moscow, Russia
Keywords: astronomic catalogue, space object, reference star, recognition, spectrophotometry, photometric observations

Abstract >>
A method of determining the type of objects under observation based on identification of the photometric portrait of the object with one of those available in the database of the current and reference photometric portraits of objects is considered. The proposed approach allows known typical objects to be identified regardless of availability of a priori information about them.



11.
PHYSICALLY CORRECT VISUALIZATION OF FUNCTIONALLY DEFINED OBJECTS

S. I. Vyatkin, B. S. Dolgovesov
Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: physically correct visualization, functionally defined objects, perturbation functions, specular reflection, diffuse reflection, diffraction, subsurface scattering

Abstract >>
Functionally defined objects for realistic scenes are proposed. Physically correct visualization of three-dimensional objects based on perturbation functions is described. That is, the rendering of materials takes into account the laws of physics. Physically correct reflection models are necessary to obtain photorealistic images. The roughness, micro relief, and surface gloss indicate how smooth or rough the surface of the material is. This paper shows the effects of diffraction taking into account the surface roughness. Subsurface light transport is also considered, which is modeled using bidirectional surface scattering.



12.
STUDY OF THE OPERATION OF A MICROWAVE SIGNAL CONVERTER BASED ON A FIBER ELECTRO-OPTICAL INTENSITY MODULATOR

V.M. Vladimirov1, M.Yu. Reushev1,2, K.A. Drevin3, A.A. Semenkova4
1Federal Research Center Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
3NPF Electron LLC, Krasnoyarsk, Russia
4Reshetnev Siberian State University of Science and Technology, Krasnoyarsk, Russia
Keywords: microwave signal conversion, electro-optical modulator, difference frequency generation

Abstract >>
The characteristics of a fiber electro-optical intensity modulator in the mode of conversion of microwave signals are investigated. The optimal conditions for efficient generation of the difference frequency of mixed signals at the modulator output are determined.



13.
IMAGE FORMATION FOR AN EXTENDED SLIT HOLE OF A SYMMETRICAL TYPE WITH ABSOLUTELY ABSORBING INTERNAL FACES IN COHERENT LIGHT

Yu. V. Chugui
Technological Design Institute of Scientific Instrument Engineering, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Fresnel and Fraunhofer diffraction, Fourier optics, spectra of extended objects, volumetric slit hole, optical dimensional inspection

Abstract >>
The features of imaging faces of extended (in depth) slit holes of constant thickness d of symmetrical type (with equal input and output apertures D) with absolutely absorbing internal faces are investigated. The calculations are based on an optical-physical model of diffraction phenomena on extended absolutely absorbing objects using equivalent slit-type transparencies. The structures of images of such objects formed in ideal and diffraction-limited systems are studied. It is shown that the image profiles of the front and back faces of the extended slit hole largely depend on a parameter Nθ0 equal to the ratio of the critical diffraction angle θcr = √ λ/d to the half angular size θ0 of the aperture filter, as well as on the ratio of the slit aperture D to the size of the Fresnel zone δd = √ λd. It is shown that, when Nθ0 >> 1, there is a displacement of the object boundaries, which is determined both by the interaction of diffraction pictures of two edges for the case of a flat slit (d = 0) and by the influence of secondary diffraction of light on the back face of the extended object. At D >> √λd, the boundaries are found to be mainly shifted due to secondary diffraction of light, which leads to a systematic error of measuring the aperture D equal to εd = 0,22 δd . The features of the formation of diffraction-limited images of the back face with strong volumetric effects (Nθ0 << 1) are investigated.