Optoelectronics, Instrumentation and Data Processing (v.48, #1)

A method of constructing optimal mask differentiating filters minimizing the level of the root-mean-square or systematic error of estimation of the anisotropic structure orientation observed in the presence of additive white noise is proposed. Results of a comparative analysis of the accuracy of gradient algorithms are presented. It is demonstrated that the use of optimal differentiating filters substantially increases the accuracy of the orientation estimation algorithm
Keywords: optimal mask differentiating filters; gradient structure tensor

A class of wavelet filtration algorithms with two-parameter threshold functions is considered. An algorithm is proposed for solving the problem of choosing two threshold values, which allows estimating their optimal values with acceptable accuracy.
Keywords: wavelet filtration; threshold functions; optimal threshold value

The use of the algorithm of real-time determination of local displacements of fragments (blocks) with due allowance for spatial and temporal coupling of motion is proposed for estimating the background component during detecting small-size dynamic objects (in the case of unknown motion of the observation system). The efficiency of this method is compared with that of the methods based on affine transformations of the image as a whole. It is demonstrated that this method is more efficient and ensures background suppression in the difference frame under the condition that it is presented by large zones deforming or displacing relative to each other.
Keywords: search for dynamic objects; small-size objects; video sequence; background compensation

For information generated by an unknown memoryless source, a compression method using nonequivalent symbols is proposed and its optimality is proved.
Keywords: entropy; coding; coding cost; source of messages

A possibility of using nonparametric algorithms of pattern recognition in the problem of comparing empirical and theoretical distribution functions of random variables is considered. Results of computational experiments are analyzed.
Keywords: nonparametric statistics; pattern recognition; testing of statistical hypotheses; distribution of random variables; Kolmogorov’s test

A method that ensures superresolution in terms of angular coordinates in surveillance systems with a flat antenna array during synthesis of radio-location and radio-thermal-location images of the Earth surface with the help of an airborne station in the real beam mode is proposed. This method is based on reconstruction of reflection and emission fields.
Keywords: superresolution; antenna array; reconstruction of radio-location and radio-thermal-location images

The problem of constructing linear regression models in the presence of errors in input and output data is considered. A statistical test for detecting measurement errors in input data is proposed that does not require a preliminary consistent estimation of the coefficients under the assumption of the presence of errors. The test is validated by Monte-Carlo statistical simulation.
Keywords: regression models; errors in input data; Monte Carlo statistical modeling

A continuous ant colony algorithm is first proposed to identify fuzzy systems. It is used to construct five fuzzy systems to approximate nonlinear functions of one, two, and three variables. The effect of algorithm parameters on the approximation error is studied. A comparative analysis with other identification algorithms showed an advantage of the proposed algorithm.
Keywords: identification; fuzzy systems; continuous ant colony algorithm

Graphics processors in problems of electron tomography by E. V. Pustovalov; O. V. Voitenko; B. N. Grudin; V. S. Plotnikov (62-68).
Algorithms were developed for the tomographic reconstruction of structure from microscopic images using graphics processors of general application. The effect of noise and the choice of reconstruction filters for tomographic problems in materials science is investigated. It is shown that the use of ρ-filtration in reconstruction allows one to estimate the geometrical characteristics of three-dimensional microstructures in amorphous metal alloys.
Keywords: electron tomography; graphics processors; image filtering

One possible variant of solving the problem of guidance of an autonomous unmanned underwater vehicle to a given target is considered. At large distances, navigation is based on measuring the time of propagation of acoustic signals. Short-range positioning is ensured by processing images taken by an optical camera. PID control is applied as an algorithm controlling the vehicle position and attitude in space. The proposed algorithm is implemented as a computer code and tested in a series of numerical experiments.
Keywords: autonomous unmanned underwater vehicle; positioning; acoustic data; image processing

Optical control of the radius of a wheel rolling on a rail by Yu. N. Dubnishchev; P. Ya. Belousov; O. P. Belousova; V. V. Sotnikov (75-80).
An optical method for measuring the geometric radius and velocity of slip of a wheel rolling on a rail is discussed.
Keywords: wheel radius; slip velocity; laser Doppler velocimeter; rail transport wheel control

Experimental studies of infrared photodetector arrays for detection of small objects by A. N. Galyantich; I. S. Gibin; V. V. Zolotsev; M. V. Kiselev; G. V. Kolesnikov (81-86).
This paper presents the results of experimental studies of staring infrared photodetector arrays (PDAs) designed for use in object recognition systems. A special bench was developed to determine the threshold sensitivity of PDAs to spot irradiation, i.e., the minimum excess of the signal power over the background with allowance for the measuring path and its performance. Estimations were made of the root-mean-square (RMS) noise of the PDA element which determines the detection threshold of the excess of the radiation power of an object over the background in the plane of the entrance pupil.
Keywords: black body; photodetector array; experimental bench; test object; contrast; detection system

Laser illuminator based on diffraction elements for training systems by N. Yu. Nikanorov; A. G. Poleshchuk; A. R. Sametov (87-92).
The use of a diffractive optical element (DOE) in the optical scheme of a laser illuminator of a shooting simulator exposing the target is studied. It is proposed to use the DOE in the optical projection system to form a laser beam with a special intensity profile. The use of the DOE with binary amplitude transmission allows simplification of the manufacture of this block with simultaneous improvement of its performance. The DOE is used as a diffraction attenuator of laser radiation with a period of 2.5 µm and a minimum bandwidth of about 0.8 µm. Results of an experimental study of the laser radiation distribution generated using the DOE and its comparison with distribution of radiation obtained in the usual way are presented.
Keywords: diffractive optical element; simulator; formation of laser radiation

A method for controlling the asymmetry sign of the spectral intensity of light reflected from a narrow-band filter by fitting the dielectric layer thickness adjacent to the thin metal layer is proposed.
Keywords: thin metal layer; multi-layer coating; optical reflection filter

The geometry of anisotropic light diffraction in ultrasound waves excited by a multi-element converter in an optically uniaxial negative crystal of lithium niobate is analyzed. An expression for the refractive index of a diffracted wave was found on the basis of a study of the optical indicatrices of the refractive indices of ordinary and extraordinary light waves in the crystal. A method for calculating the angular frequency characteristics of anisotropic acousto-optic Bragg cells with multi-element converters is proposed.
Keywords: acousto-optic Bragg cell; anisotropic light diffraction; multi-element piezoelectric converter

Effect of oxide layer roughness and thickness on spectral dependence of optical parameters of copper mirrors by L. Yu. Mel’nichenko; L. V. Poperenko; I. A. Shaikevich (102-104).
Two copper mirrors with different surface roughness are studied by means of spectroscopic ellipsometry. It is established that spectral dependences of optical conductivity are qualitatively similar, but shifted along the ordinate, and some of their peaks may be related to light absorption by the surface oxide layer.
Keywords: surface roughness; surface oxide layer; ellipsometry; optical constants; massive copper mirrors

Gallium arsenide ion-doped field-effect transistors with a Schottky barrier and various doping profiles are modeled. Dependences of static transistor characteristics on doping profile parameters are calculated and analyzed. The physical processes that determine the transistor characteristics with variation in doping profile parameters are studied.
Keywords: FET; modeling; ion implantation