Home – Home – Jornals – Avtometriya 2011 number 1

An estimation algorithm for the trajectory of a mark-making object is developed which does not require interactive selection of the region of marks. An adequate measure of the straightness of marks is proposed which allows quantitative evaluation of the performance of the estimation algorithms. Results of experimental studies are given that support the possibility of using the gradient structure tensor to estimate moving object trajectories from images obtained during motion analysis

One analytical relation needed for calculating the probability of errorless readout of random discrete images by integrators with two threshold levels is proved. A specific feature of this study is the fact that the relation proved in this paper has been first obtained through analytical calculations on a computer.

Operation principles of locally spatial filtration algorithms and wavelet filtration algorithms are described. Numerous computational experiments are performed with filtration of two different images distorted by noise with different statistical natures (white, color, and pulsed). Based on the analysis of the results obtained, recommendations on using the image filtration algorithms considered are given.

A new algorithm for detecting abandoned objects is proposed. The algorithm is based on analyzing the space and time characteristics of the overall background, background consisting of stationary objects, and current image of the video sequence. The algorithm can operate under conditions of short-time overlapping of the abandoned object, has a moderate computational complexity, and is designed for application in video surveillance systems

A method of digital filtration of experimental data sequences with the use of approximation spline functions is proposed. A problem of digital filtration on the basis of such functions is posed, and its general solution is given. An example of constructing approximation spline functions with control at the ends of observation intervals is considered. Results of digital filtration of aerodynamic experimental data with the use of the method developed are described.

Approximation of structure functions (SFs) using orthogonal polynomials in most cases, leads to an incorrect determination of the spectral power density for the obtained orthogonal model. A method for constructing orthogonal models of SFs is proposed based on preliminary shifting of the analyzed SF and using orthogonal functions as the bases. In this method, the expansion coefficients are determined using a numerical-analytical approach, which allows one to determine orthogonal models of SFs with a small approximation error and calculate spectral power density with greater accuracy. The implementation of the algorithms for constructing orthogonal models of SFs in the Laguerre and Legendre bases is considered.

We consider one of the important problems of information theory-the compression of data, in particular images, without loss of quality. An efficient image compression algorithm based on two-step coding. A comparison of experimental results of this algorithm and the JPEG-LS halftone image compression standard confirms the efficiency of the proposed method.

A modified quasioptimal method is proposed to control multielement antenna arrays by optimizing its integral parameters in controlling the complex current amplitudes in some of the array elements. Analytical estimates showing a significant reduction in computational effort were supported by calculations

A regularization method for estimating the directions to sources of coherent radio signals was developed which takes into account the vector nature of the electromagnetic field of incident waves and complex radiation patterns of antenna elements and does not depend on the incident wave polarization.

Implementation of a coupled finite element method of modeling of diffraction of electromagnetic waves on periodic inhomogeneities on substrates and in free space is discussed. The region including a periodic distribution of permittivity and permeability is covered with a finite element mesh. The variational equation incorporating field values in mesh nodes is minimized in accordance with the finite element method. The Rayleigh expansion is applied to field values in homogeneous half-space domains below and above the calculation domain including the inhomogeneity. Numerical experiments are performed to analyze the solution convergence dependence on the element size.

A noiseless algorithm for analyzing phase-shifting interferograms is proposed

A stereoscopic visual space constructed on the basis of a three-dimensional Trehub's retinoid is considered. For the eye model used, this space is demonstrated to correspond to the Renaissance perspective observed by a cyclopean eye, with the sight range being proportional to the linear parallax of points. Advantages and drawbacks of proposed models of visual perception are analyzed

A gas-droplet flow generated by a pneumatic injector with internal mixing is studied by optical methods. The fractional composition and the spatial distribution of liquid droplets for different fractions are measured, as well as the mean velocity field.

A laboratory system for recording and analyzing acoustic emission was designed and experimentally investigated (tested). A block diagram and the operation algorithm of the system are presented. The relationship between the results of low-frequency, high-frequency, and statistical processing of recorded data and the physical features of input signals is shown using as an example simulated acoustic signals in the various units of the designed system. The system was tested on real test objects in the case of three-point bending of nitrided steel specimens with various thicknesses of the hardened surface layer. It is shown that crack formation leads to emission of signals with an amplitudes of up to 4 V, whereas during deformation in the absence of pronounced cracking, the amplitude of the amplified signal does not exceed 0.5 V.