Статьи журнала - Компьютерная оптика

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High-speed recursive-separable image processing filters

High-speed recursive-separable image processing filters

Kamenskiy Andrey Victorovich

Статья научная

The development of modern technologies in the field of image formation leads to an increase in the size of the generated images, as a result the question of reducing the processing computational costs arises, and this is an important factor in the creation of real-time systems. The study provides a description of high-speed recursive-separable filters for improving the quality of images, which, due to the peculiarities of their implementation, can reduce the number of computational operations required for the image processing process. This type of filters is obtained from two-dimensional linear digital filters, which are modified by applying recursive and separable properties to them. The MATLAB environment computing method for implementation of these filters is described. An extensive performance research of the developed filters has been carried out at various sizes of the test image and on various experimental installations. The comparison with the classical two-dimensional convolution method of the developed filters is demonstrated, and it shows the time gain required for the image processing. The results obtained can be applied in biomedical image processing systems or in vision systems working in heavy weather conditions.

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High-speed recursive-separable image processing filters with variable scanning aperture sizes

High-speed recursive-separable image processing filters with variable scanning aperture sizes

Kamenskiy A.V., Kuryachiy M.I., Krasnoperova A.S., Ilyin Yu.V., Akaeva T.M., Boyarkin S.E.

Статья научная

In the process of development of computer technologies, the number of areas of their application naturally grows and, along with it, the complexity of the tasks to be solved, which entails the need for new research. Similar tasks include digital filtering of images in the field of medical technologies and active-pulse television measuring systems. There are many methods and algorithms of digital filtering designed to solve the problem of improving the quality; algorithms that can improve the quality of images while reducing computational costs are widely used. High demands, which are made due to the constant growth in the size of the generated images, as well as the requirement for modern television systems, is real-time operation. When solving practical problems, it is required to use different filter aperture sizes, which provide an increase in quality and preservation of image details. The solution of these problems was the reason for the emergence of adaptive filters that are able to change the parameters in the process of processing the received data, while not spending additional time on processing with an increase in the size of the aperture. The paper presents the principles of constructing adaptive image processing filters, which, by obtaining an input parameter indicating the required dimension of a multi-element aperture, are able to implement the construction of the required aperture. The Laplacian “Truncated Pyramid” filter and the “double pyramid” Laplacian were modified. A feature of these filters is the oddness of the multi-element aperture, so the coefficient used to build the mask is always set to odd. When using these filters, it is possible to use two coefficients that are responsible for increasing the filtration efficiency, since, in their original form, the Laplacian filters have a sum of coefficients equal to zero. The experiment shows a comparison with high-dimensional filters that work when using classical two-dimensional convolution. The next stage of the presented research will be the application of parallel computing techniques, which will increase the speed of the developed filters.

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Hybrid Tamm-cavity modes in photonic crystal with resonant nanocomposite defect layer

Hybrid Tamm-cavity modes in photonic crystal with resonant nanocomposite defect layer

Vetrov Stepan Yakovlevich, Avdeeva Anastasia Yurievna, Pyatnov Maxim Vladimirovich, Timofeev Ivan Vladimirovich

Статья научная

Hybrid optical modes in a one-dimensional photonic crystal with a resonant nanocomposite defect bounded by a metallic layer are studied. The nanocomposite consists of spherical metallic constituents, that are distributed in a dielectric matrix. Transmittance, reflectance, and absorbance spectra of this structure, which is shined by light with normal incidence, are calculated. The possibility of control of the hybrid modes spectral characteristics by changing the thickness of the layer adjacent to the metal, the number of layers, and the nanocomposite filling factor is shown.

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Hyperspectral image segmentation using dimensionality reduction and classical segmentation approaches

Hyperspectral image segmentation using dimensionality reduction and classical segmentation approaches

Myasnikov Evgeny Valerevich

Статья научная

Unsupervised segmentation of hyperspectral satellite images is a challenging task due to the nature of such images. In this paper, we address this task using the following three-step procedure. First, we reduce the dimensionality of the hyperspectral images. Then, we apply one of classical segmentation algorithms (segmentation via clustering, region growing, or watershed transform). Finally, to overcome the problem of over-segmentation, we use a region merging procedure based on priority queues. To find the parameters of the algorithms and to compare the segmentation approaches, we use known measures of the segmentation quality (global consistency error and rand index) and well-known hyperspectral images.

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Hyperspectral remote sensing data compression and protection

Hyperspectral remote sensing data compression and protection

Gashnikov Mikhael Valeryevich, Glumov Nikolay Ivanovich, Kuznetsov Andrey Vladimirovich, Mitekin Vitaly Anatolyevich, Myasnikov Vladislav Valerievich, Sergeyev Vladislav Victorovich

Статья научная

In this paper, we consider methods for hyperspectral image processing, required in systems of image formation, storage, and transmission and aimed at solving problems of data compression and protection. A modification of the digital image compression method based on a hierarchical grid interpolation is proposed. Methods of active (on the basis of digital watermarking) and passive (on the basis of artificial image distortion detection) data protection against unauthorized dissemination are developed and investigated.

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Image compression and encryption based on wavelet transform and chaos

Image compression and encryption based on wavelet transform and chaos

Gao Haibo, Zeng Wenjuan

Статья научная

With the rapid development of network technology, more and more digital images are transmitted on the network, and gradually become one important means for people to access the information. The security problem of the image information data increasingly highlights and has become one problem to be attended. The current image encryption algorithm basically focuses on the simple encryption in the frequency domain or airspace domain, and related methods also have some shortcomings. Based on the characteristics of wavelet transform, this paper puts forward the image compression and encryption based on the wavelet transform and chaos by combining the advantages of chaotic mapping. This method introduces the chaos and wavelet transform into the digital image encryption algorithm, and transforms the image from the spatial domain to the frequency domain of wavelet transform, and adds the hybrid noise to the high frequency part of the wavelet transform, thus achieving the purpose of the image degradation and improving the encryption security by combining the encryption approaches in the spatial domain and frequency domain based on the chaotic sequence and the excellent characteristics of wavelet transform...

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Image compression using discrete orthogonal transforms with the «Noise-like» basis functions

Image compression using discrete orthogonal transforms with the «Noise-like» basis functions

Chernov V.M., Dmitriyev A.G.

Статья научная

The generalization of the discrete orthogonal transforms with the basis functions generated in a pseudorandom way is the subject of the article. The examples of such transforms application in the field of videoinformation coding in the channels with the high level of «seldom» noise are also given.

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Improvements of programing methods for finding reference lines on X-ray images

Improvements of programing methods for finding reference lines on X-ray images

Al-Temimi Ammar Mudheher Sadeq, Pilidi Vladimir Stavrovich

Статья научная

The paper gives an overview of the algorithms developed to obtain reference lines and angles on X-ray images. These geometrical characteristics are used in the medical analysis of human joints. We propose the algorithm’s modifications based on the analysis of numerous X-ray images. These modifications allowed obtaining a great increase in calculation speed and the improvement of final results quality given by the corresponding application. They also lead to a significant reduction of manual tuning of the program, arising only in the rare cases when the properties of given images differ significantly from the mean ones.

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Indexing of computer optics in the emerging sources citation index database

Indexing of computer optics in the emerging sources citation index database

Stafeev Sergey S.

Ред. заметка

Inclusion of the journal Computer Optics in the Emerging Sources Citation Index database is described in this editorial.

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Integrated fiber-based transverse mode converter

Integrated fiber-based transverse mode converter

Gavrilov Andrey Vadimovich, Pavelyev Vladimir Sergeevich

Статья научная

A transverse mode converter based on a binary microrelief implemented directly on the end-face of a few-mode fiber was numerically investigated. The results of numerical simulation demonstrated the converter to form LP-11 and LP-21 modes with high efficiency, providing a more-than 92 % mode purity. Transformations of modes excited by a fiber microbending were also numerically investigated. The excited beams were shown to save their mode purity even in a strong bending as the arising parasitical modes were mostly unguided by the fiber. The resulting beam power and mode content were also demonstrated to depend on the beam and bending mutual orientation for beams with strong rotational symmetry.

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Interative-phase method for diffractively levelling the Gauss beam intensity

Interative-phase method for diffractively levelling the Gauss beam intensity

Golub М.А., Doskolovich L.L., Kotlyar V.V., Nikolsky I.V., Soifer V.A.

Статья научная

The phase diffractive optical element that transforms the Gaussian collimated beam into the uniformly illuminated rectangle has been calculated. In computing the phase function we have employed an adaptive iterative algorithm which is generalization of the Gerchberg-Saxton method. The smooth phase function derived using geometrical optical methods has been used as an initial approximation.

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Interferometric testing of steep cylindrical surfaces with on-axis CGHs

Interferometric testing of steep cylindrical surfaces with on-axis CGHs

Poleshchuk Alexander Grigorievich, Nasyrov Ruslan Kamilyevich, Asfour Jean-Michel

Статья научная

We present a new approach for testing cylindrical optical surfaces using a Null-test. We suggest using a Co mp uter Ge nerated Hologra m (CG H) in co mbi natio n w ith a Trans mission Sp here. It is shown that in such an optical layout the period of the diffractive structure is larger than in the case of a conventional scheme using a collimated beam. Therefore, this kind of hologram enables the test of cylinder surfaces with higher numerical apertures.

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Invariant laser beams - fundamental properties and their investigation by computer simulation and optical experiment

Invariant laser beams - fundamental properties and their investigation by computer simulation and optical experiment

Pavelyev Vladimir S., Michael Duparr Michael, Luedge Barbara, Soifer Victor A., Kowarschik Richard, Golovashkin Dimitriy L.

Статья научная

Laser light modes are beams in whose cross-section the complex amplitude is described by eigenfunctions of the operator of light propagation in the waveguide medium. The fundamental properties of modes are their orthogonality and their ability to retain their structure during propagation for example in a lenslike medium, in free space or a Fourier stage. Novel Diffractive Optical Elements (DOEs) of MODAN-type [1] open up new promising potentialities of solving the tasks of generation, transformation, superposition and subsequent separation again of different laser modes. Now we present new results obtained by synthesis and investigation of beams consisting of more than one twodimensional Gaussian laser modes with the same value of propagation constant (invariant multimode beams) formed by DOEs. The exploitation of these phenomena could enhance the fiber optical system transfer capacity without pulse enlargement.

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Investigation of the resolution of phase correcting Fresnel lenses with small values of F/D and subwavelength focus

Investigation of the resolution of phase correcting Fresnel lenses with small values of F/D and subwavelength focus

Minin I.V., Minin O.V., Gagnon N., Petosa A.

Статья научная

The focusing properties of phase correcting Fresnel lenses with small values of focal length - to - diameter (F/D) and with focal lengths of two wavelengths or less are investigated. For these lenses, the paraxial approximation for the Rayleigh resolution criterion is no longer valid. For Fresnel lenses designed with F/DF ≤ λ, spatial resolutions of less than 0.5λ are possible, which is finer than what can typically be achieved for conventional (paraxial) designs. The spot beams in these cases are not quite axially symmetrical due to the presence of anti-symmetric field components, which vanish for larger values of F/D.

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Laser beam characterization by means of diffractive optical correlation filters

Laser beam characterization by means of diffractive optical correlation filters

Pavelyev V.S., Soifer V.A., Duparre M., Luedge B.

Статья научная

Analyzing of amplitude-phase characteristics of laser beam is topical in experimental physics and in a great number of laser applications, such as, for example, laser material treatment. The task of analyzing the amplitude-phase beam structure may be treated as that of analyzing the modal composition, if this is thought of as both analyzing individual modal powers and intermode phase shifts. In this paper the problem is tackled using a special diffractive optical element (DOE), called MODAN, matched to a group of laser radiation modes and their special combinations. The experimental results reported indicate that such an approach shows promise. Key words: laser beam, Gaussian modes, intermode power distribution, intermode phase shifts.

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MIDV-2020: a comprehensive benchmark dataset for identity document analysis

MIDV-2020: a comprehensive benchmark dataset for identity document analysis

Bulatov Konstantin Bulatovich, Emelianova Ekaterina Vladimirovna, Tropin Daniil Vyacheslavovich, Skoryukina Natalya Sergeevna, Chernyshova Yulia Sergeevna, Sheshkus Alexander Vladimirovich, Usilin Sergey Alexandrovich, Ming Zuheng, Burie Jean-Christophe, Luqman Muhammad Muzzamil, Arlazarov Vladimir Viktorovich

Статья научная

Identity documents recognition is an important sub-field of document analysis, which deals with tasks of robust document detection, type identification, text fields recognition, as well as identity fraud prevention and document authenticity validation given photos, scans, or video frames of an identity document capture. Significant amount of research has been published on this topic in recent years, however a chief difficulty for such research is scarcity of datasets, due to the subject matter being protected by security requirements. A few datasets of identity documents which are available lack diversity of document types, capturing conditions, or variability of document field values. In this paper, we present a dataset MIDV-2020 which consists of 1000 video clips, 2000 scanned images, and 1000 photos of 1000 unique mock identity documents, each with unique text field values and unique artificially generated faces, with rich annotation. The dataset contains 72409 annotated images in total, making it the largest publicly available identity document dataset to the date of publication. We describe the structure of the dataset, its content and annotations, and present baseline experimental results to serve as a basis for future research. For the task of document location and identification content-independent, feature-based, and semantic segmentation-based methods were evaluated. For the task of document text field recognition, the Tesseract system was evaluated on field and character levels with grouping by field alphabets and document types. For the task of face detection, the performance of Multi Task Cascaded Convolutional Neural Networks-based method was evaluated separately for different types of image input modes. The baseline evaluations show that the existing methods of identity document analysis have a lot of room for improvement given modern challenges. We believe that the proposed dataset will prove invaluable for advancement of the field of document analysis and recognition.

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MIDV-500: a dataset for identity document analysis and recognition on mobile devices in video stream

MIDV-500: a dataset for identity document analysis and recognition on mobile devices in video stream

Arlazarov Vladimir Viktorovich, Bulatov Konstantin Bulatovich, Chernov Timofey Sergeevich, Arlazarov Vladimir Lvovich

Статья научная

A lot of research has been devoted to identity documents analysis and recognition on mobile devices. However, no publicly available datasets designed for this particular problem currently exist. There are a few datasets which are useful for associated subtasks but in order to facilitate a more comprehensive scientific and technical approach to identity document recognition more specialized datasets are required. In this paper we present a Mobile Identity Document Video dataset (MIDV-500) consisting of 500 video clips for 50 different identity document types with ground truth which allows to perform research in a wide scope of document analysis problems. The paper presents characteristics of the dataset and evaluation results for existing methods of face detection, text line recognition, and document fields data extraction. Since an important feature of identity documents is their sensitiveness as they contain personal data, all source document images used in MIDV-500 are either in public domain or distributed under public copyright licenses. The main goal of this paper is to present a dataset. However, in addition and as a baseline, we present evaluation results for existing methods for face detection, text line recognition, and document data extraction, using the presented dataset.

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Many heads but one brain: fusionbrain - a single multimodal multitask architecture and a competition

Many heads but one brain: fusionbrain - a single multimodal multitask architecture and a competition

Bakshandaeva Daria Dmitrievna, Dimitrov Denis Valerievich, Arkhipkin Vladimir Sergeyevich, Shonenkov Alex Vladimirovich, Potanin Mark Stanislavovich, Karachev Denis Konstantinovich, Kuznetsov Andrey Vladimirovich, Voronov Anton Dmitrievich, Petiushko Aleksandr Alexandrovich, Davydova Vera Fedorovna, Tutubalina Elena Viktorovna

Статья научная

Supporting the current trend in the AI community, we present the AI Journey 2021 Challenge called FusionBrain, the first competition which is targeted to make a universal architecture which could process different modalities (in this case, images, texts, and code) and solve multiple tasks for vision and language. The FusionBrain Challenge combines the following specific tasks: Code2code Translation, Handwritten Text recognition, Zero-shot Object Detection, and Visual Question Answering. We have created datasets for each task to test the participants' submissions on it. Moreover, we have collected and made publicly available a new handwritten dataset in both English and Russian, which consists of 94,128 pairs of images and texts. We also propose a multimodal and multitask architecture - a baseline solution, in the centre of which is a frozen foundation model and which has been trained in Fusion mode along with Single-task mode. The proposed Fusion approach proves to be competitive and more energy-efficient compared to the task-specific one.

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Many-parameter m-complementary Golay sequences and transforms

Many-parameter m-complementary Golay sequences and transforms

Labunets Valeri Grigorievich, Chasovskih Victor Petrovich, Smetanin Yuri Gennadievich, Ostheimer Rundblad Ekaterina

Статья научная

In this paper, we develop the family of Golay–Rudin–Shapiro (GRS) m-complementary many-parameter sequences and many-parameter Golay transforms. The approach is based on a new gen-eralized iteration generating construction, associated with n unitary many-parameter transforms and n arbitrary groups of given fixed order. We are going to use multi-parameter Golay transform in Intelligent-OFDM-TCS instead of discrete Fourier transform in order to find out optimal values of parameters optimized PARP, BER, SER, anti-eavesdropping and anti-jamming effects.

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Mapping and evaluating urban density patterns in Moscow, Russia

Mapping and evaluating urban density patterns in Moscow, Russia

Choudhary Komal, Boori Mukesh Singh Boori, Kupriyanov Alexander Victorovich

Статья научная

The defense of the notion of ‘compact city’ as a strategy to reduce urban sprawl to support greater utilization of existing infrastructure and services in more compact areas and to improve the connectivity of employment hubs is actively discussed in urban research. Using the urban residential density as a surrogate measure for urban compactness, this paper empirically examines a cadaster database that contains details of every property with a view of capturing changes in urban residential density patterns across Moscow using geospatial techniques. The policy of densification in chase of a more compact city has produced mixed results. Findings of this study signal that the urban densities across the buffer zones around Moscow city are significantly different. The Landsat images from 1995, 2005 and 2016 are classified based on the maximum likelihood to expand the land use/cover maps and identify the land cover. Then, the area coverage for all the land use/cover types at different points in time is combined with the distance from the city center. After that, urbanization densities from the city center toward the outskirts for every 1-km distance from 1 to 60 km are calculated. The city density on the distance of 1 to 35 km is found to be very high in the years 1995 to 2016. As usual, the population, traffic conditions, industrialization and government policy are the major factors that influenced the urban expansion.

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