Journal Issue: Научная визуализация
Загружается...
Volume
2023-15
Number
4
Issue Date
Journal Title
Journal ISSN
2079-3537
Том журнала
Том журнала
Научная визуализация
(2023-15)
Статьи
Публикация
Открытый доступ
Computer Vision Study of the Flow Generated by a Sliding Discharge
(НИЯУ МИФИ, 2023) Znamenskaya, I. A.; Doroshchenko, I. A.; Sysoev, N. N.
A quantitative study has been made of the flow with shock waves generated in air by a sliding surface discharge lasting less than one microsecond. The high-speed flow was visualized using the shadowgraph method, the process was recorded at a rate of 124 000 frames/s, the exposure time was 1 µs. The aim of this work is to study the dynamics of the two discontinuities: the cylindrical shock wave and the contact surface generated by the discharge. Each experiment allowed several hundred images to be taken of a short-lived gas-dynamic process lasting up to 1 ms. A YOLOv8 convolutional neural network was trained and used to determine the positions of the discontinuities. A data set of 984 markups was labeled. The model on the mAP50 metric achieved 0.887 and the mAP50-95 was 0.557. The model was used to automatically measure the vertical dimensions of the contact discontinuity. It expands at times up to 0.4 - 0.8 ms to a vertical size of 5 - 11 mm. The x-t plots and the velocities of the cylindrical shock waves were measured. It is shown that up to 1 ms after the discharge, the flow development is due to the blast wind motion behind the shock wave. It is shown that the use of computer vision can significantly speed up the analysis of high-speed flow visualizations and the extraction of quantitative information.
Публикация
Открытый доступ
On Application of Canonical Decomposition for the Visualization of Results of Multiparameter Computations
(НИЯУ МИФИ, 2023) Alekseev, A. К.; Bondarev, A. E.; Pyatakova, Yu. S.
The approximation of the tensor appearing at a discretization of the multidimensional function is considered from the viewpoint of storing and treating of the results of parametric computations obtained in computational aerogasdynamics. The new algorithm for the computation of the canonical decomposition using gradient descent and approximately decomposable goal functional is described. This algorithm applies the random set of points on the hyperplane orthogonal to the computed core of the canonical decomposition (“umbrella”) that ensures its flexible application for an approximation of the tensors with a priori unknown rank and may be naturally transferred on such tensor decomposition as the tensor train. The results of the numerical tests are presented for the model six-dimensional functions and for an ensemble of the numerical solutions for the two-dimensional Euler equations. These equations describe the flow of the compressible gas with two crossing shock waves. The Mach number and angles of the flow deflection serve as the flow parameters. The results are provided for the dimensionality 3 (simple numerical solution) and 4 (the ensemble of the numerical solutions in dependence on the Mach number).
Публикация
Открытый доступ
RLaMs-Dehazing: Optimized Depth Map Improvement Single Colour Image Dehazing
(НИЯУ МИФИ, 2023) Sangita Roy
Visibility Degradation is a classical problem owing to the presence of Atmospheric Particulate Matter (APM). There are different image dehazing algorithms. Any one method cannot be relied upon as each haze condition is unique. An innovative algorithm has been proposed inverting the image formation atmospheric scattering model [2, 32]. The model has been improvised by one key factor. This is Regularized Lagrangian multiplier (RLaM) based Depth Map (DM) refinement. The algorithm has low time complexity which intrigues real-time efficient applications. Different state-of-the-art visibility algorithms have been studied and their subjective and objective performance evaluations have been evaluated. Extensive investigation shows remarkable improvement with the proposed algorithm. This method is equally applicable to different atmospheric conditions. Time complexity experimented with execution time and Big (O) for real-time effectiveness. Extensive experiment results show the potential of the proposed algorithm independent of the influence of atmospheric conditions and capturing devices adaptive to computer vision applications. Time complexity and quality output trade-off achieved with the removal of ringing artifacts efficiently
Публикация
Открытый доступ
Application of Scientific Visualization in Low-Temperature Gas Discharge Plasma Modeling
(НИЯУ МИФИ, 2023) Budak, V. P.; Zheleznov, I. I.
This article discusses the importance of developing software and hardware complexes for data visualization and improving methods of presenting them in the modeling of lowtemperature gas discharge plasma phenomena and related physical processes. In particular, issues related to creating a specialized distributed environment for solving gas discharge modeling tasks are considered. The use of computer graphics for visualization has allowed for a visual analysis of the obtained data and making necessary adjustments to the modeling process interactively with the data. The paper presents the results of visualizing a model of mercury-argon plasma in a coaxial microwave discharge. The application of local crosssections of the computational domain for visualization has revealed the internal structure and peculiarities of the distribution of the electric field and electron concentration in the discharge tube. The obtained data served as the basis for creating an experimental prototype of a coaxial gas discharge optical radiation source.
Публикация
Открытый доступ
Gauss-Newton Method in the Problem of Optimizing the Axisymmetric Phase Function Calculation Based on the Hilbert Diagnostic Data
(НИЯУ МИФИ, 2023) Arbuzov, E. V.; Arbuzov, V. A.; Dubnishchev, Yu. N.; Zolotukhina, O. S.
A method for reconstructing phase disturbances of a probing light field using the iterative Gauss-Newton algorithm is discussed as part of the Hilbert diagnostics development of gaseous, condensed and reacting media. In this case, the need to determine second derivatives is eliminated, which simplifies the calculations. The method consists of selecting a phase profile, which is specified by a Bezier curve, and hilbertogram calculating. The coincidence of the reference and reconstructed hilbertograms serves as a criterion for the results reliability. The Jacobian matrix for the nonlinear integral operator of Hilbert visualization is obtained. The algorithm is analyzed using a test function. The method development is associated with the algorithm application to the processing of experimental results, including the reconstruction of complex structures in which the phase function is described by several Bezier polynomials.