Home – Home – Jornals – Avtometriya 2003 number 2

The nondisturbing diagnostics of gyroscopic wave structures on the surface of rotating media in the inertial and noninertial coordinate systems is discussed. The possibility of observing the Earth

A new optical method for studying flows in regular structures consisting of optically transparent balls is discussed. It is based on using elements of such a structure as a complex objective. The distortion arising in the system is corrected by symmetrical positioning of the entrance pupil relative to the optical system.

Search for technological conditions of manufacturing diffused waveguides in a neodymium-doped laser glass of the GLS-10 type is carried out. Fabrication of integral-optical waveguides by ion exchange from a melt of AgNO₃ + KNO₃ salt and by PbO solid-state diffusion is considered. Efficient refractive indices and the number of wave modes of the produced waveguides are determined.

A scheme of reconstructing, in view of the volume, a nonaxial volume cylindrical holographic optical element (HOE) on the basis of analyzing its characteristic function is calculated, as well as the conditions of forming the adjacent planes. A mirror-lens model of the nonaxial cylindrical HOE is proposed. It differs from the mirror and lens models of a thin HOE and allows one to determine graphically the adjacent planes of the object and the image. A rule for constructing the adjacent planes is presented.

A method is proposed to determine experimentally the signal-to-scattering noise ratio in recording a volume holographic optical element (HOE). The method allows one to find the average diffraction efficiency of noise gratings in the presence of misalignment between the interference pattern and the recorded HOE. The calculated values of SNR agree with experimental ones for great values of the efficiency. The rates of growing efficiencies of HOE and noise gratings are comparable, and this hampers production of high-efficient HOE with a low noise level.

A method for reconstructing wavefronts obtained by shifting interferometry is considered. The incorrectness inherent in the known approaches used to measure asymmetric wavefronts is eliminated. An algorithm is proposed for increasing the computational efficiency and extending the field of application of shifting interferometry.

A method and equipment for measuring ultra small phase increments of a heterodyne high-frequency laser vibrometer signal are considered. It is shown that the sensitivity can be increased by transferring the signal spectrum to an intermediate frequency of 14.7 kHz followed by obtaining three-phase samples of the difference frequency, which serve to eliminate the ADC offset drift and calculate the coherent and quadrature components of the analytical signal. A computer calculated the amplitude and phase of the analytical signal.

An automated system is developed for depositing polymer films of compositions with a viscosity of 10

New devices for recording and testing photopolymer transmission and reflection holograms are presented. They allow one to investigate dynamics of their diffraction efficiency, spectral, noise, and other characteristics.

Nanoscale potential barriers and wells on the basis of solid Cd_xHg_1-x Te (MCT) solutions have been grown by molecular-beam epitaxy with in situ precision ellipsometric control of the thickness and composition of the layers. Decaying oscillations of ellipsometric parameters are observed during MCT growth with a variable molecular flux of tellurium. A comparison of experimental and calculated data allows one to determine the MCT composition of a thin layer corresponding to a potential barrier of well and its thickness, and evaluate the sharpness of boundaries. It is demonstrated that the grown potential barriers and wells with different MCT compositions, whose thickness varies from 2 to several dozens of nanometers, have sharp boundaries within one monolayer.

The game-theoretical approach to organizing dispatching distributed computing systems (CS) in the state of maintaining a stream of parallel tasks is developed. Parallel algorithms of seeking for the optimal mixed strategies for choice of tasks for solution on not absolutely reliable CS are proposed. Results on parallel simulation of distributed CS functioning are presented.

A method for constructing models of digital photocamera calibration to improve color reproduction in the form of multiresponse regression models is considered. The model is based on the process of constructing in the color space Lab a correction function in the form of an incomplete third-order polynomial with linearization of color parameters. Advises for estimating the coefficients of the models by the maximum likelihood method are given. Comparative results on analysis of color correction accuracy are presented.

It is shown that the energy image spectrum can be described by a set of spectral moments used as an instrumental spectrum estimate in solving some problems of image analysis and classification. An analytical relationship between the power characteristics of signals in the space and frequency regions, which extends the Rayleigh theorem to moments of any arbitrary order of the function of two variables, is obtained. It is proved that a moment of any high order in the frequency domain is always in correspondence with the second-order moment in the space region. A spectral moment calculation algorithm is presented.

A block-structural representation of feedback systems allows one to separate motions of a complex object by the simplest procedure and thereby increase the efficiency of present-day CAD systems at stages of improving the equipment. It is shown that the most universal method for analyzing automatic control systems is the matrix-free simulation method. It is proposed to use a simulation method ensuring calculations with a variable balanced error and the minimum labor consumption, along with the motion separation principle.

Some problems arising in designing computer driving simulators (DS) based on PC are considered. Examples of possible DS applications are presented. Components of the typical DS are listed.