Optoelectronics, Instrumentation and Data Processing (v.52, #4)
Using fuzzy sets to estimate the geometric parameters of surface damage by I. V. Konovalenko; O. A. Pastukh; P. O. Marushchak (319-327).
This paper considers the influence of the variable parameters of a surface defect detection algorithm on the result of its operation. A method for estimating the influence of the variable parameters on the recognized geometric characteristics of the surface defect network is proposed. This method is based on representing the basic zones of the skeleton of the surface damage network in the form of compact fuzzy sets in two-dimensional space (fuzzy quasi-points). The set of points of the recognized object obtained for various combinations of the test algorithm parameters is represented in the form of a fuzzy set with a certain membership function. A method for calculating the geometric parameters of the damage network (length and slope) by means of fuzzy geometry is considered, and its use for determining the geometric parameters of the damage network of a continuous casting roller is demonstrated.
Keywords: image recognition; damage detection; fuzzy quasi-point; fuzzy geometry; fuzzy distance
Effect of the radiation pattern on the quality of object image reconstruction in circular aperture synthesis by V. P. Yushchenko; S. A. Litvinenko (328-333).
This paper addresses the problem of the acoustic wave reception sector of a tomograph detector in an aqueous medium, whose solution anticipates the development of a tomograph with circular aperture synthesis in monochromatic probing. In the theoretical consideration of the problem of object image reconstruction, the transducer radiation pattern was assumed to be isotropic in the plane, i. e. disk-shaped, with an unlimited circular reception sector, which allows investigation of the internal structure of the object in the plane of the radiation pattern disk. The effect of the deviation from isotropy due to the limitation of the acoustic wave reception sector on the results of image reconstruction of a point object is determined by modeling the reconstruction of a point object image from trajectory Doppler signals received by the detector moving on a circular path around the point object.
Keywords: synthetic aperture; trajectory Doppler signal; image reconstruction; point transfer function; reference trajectory signals; correlation processing
Functional observer design using linear matrix inequalities by V. G. Volkov; D. N. Dem’yanov (334-340).
It is shown that the problem of observer design for estimating a set of linear combinations of state variables of a plant can be formulated in terms of linear matrix inequalities. An algorithm for constructing functional observers is proposed based on a nonsingular transformation of a plant model in the state space by matrix canonization with subsequent solution of the system of linear matrix inequalities.
Keywords: estimation; functional observer; design algorithm; linear matrix inequalities; matrix canonization
Blind watermarking algorithm for a sequence of TV images by A. I. Goncharenko; I. G. Tarantsev; K. F. Lysakov (341-346).
A problem of digital watermarking of a sequence of TV images is considered. An algorithm of embedding of such watermarks based on combining singular decomposition and Haar filtration procedures and a corresponding blind algorithm of watermark retrieval are developed. It is shown that the embedded watermark is stable to basic distortions arising in the TV path, e.g., enhancement of noise, loss of definition, truncation and compression of the multimedia material by MPEG2 or AVC algorithms. Owing to noise-immune encoding, the number of correctly retrieved bits of digital watermarks can reach 100%.
Keywords: TV; steganography; blind retrieval algorithm; Haar transform; singular decomposition
Identification of the shear-type displacement vector field and evaluation of its characteristics by V. V. Kibitkin; A. I. Solodushkin; V. S. Pleshanov (347-353).
A problem of identification of a shear-type solid flow is considered. Characteristics of the shear flow are determined on the basis of the initial displacement vector field. An algorithm of formation of a finite-size model displacement field of the shear type is given. A functional is proposed to search for the amplitude and direction of the shear flow for each local area of the vector field. The influence of the size of this area and of the degree of its overlapping with the shear flow on the error of shear angle measurement is shown. The choice of the local area size is analyzed. Functional operation is demonstrated by an example of the displacement field obtained in the case of compressive loading of the Hadfield steel single crystal.
Keywords: digital image correlation method; vector field; shear flow; functional; identification; error; deformation
Using the differential method of measurement to control the accuracy of precision angle measuring structures by V. P. Kiryanov; A. V. Kiryanov; V. V. Chukanov (354-359).
Specific features of monitoring metrological parameters of optical scales, limbs, or code disks are considered. A concept of building an intelligent mechatronic module on the air bearing basis for a high-performance angle measuring machine is proposed. The result is achieved by using the differential method of measurement in the mechatronic module design. This method allows one to determine the contribution of the measuring setup to the resulting error of structures.
Keywords: angle measuring structures; differential method of measurement; angle encoder; air bearing; angle measuring setup
Detection of a seismically activity object in the region of location of an observation system using a consistent Wald test by M. A. Grigor’ev; M. A. Rajfeld (360-366).
This paper deals with the development of a sequential procedure of decision making on detection of a seismically active object in an area defined by the location of a seismic observation system. It is shown that the use of a sequentialWald test to develop the decision rule provides specified detection characteristics and decision making with minimum delay, which is an important requirement for seismic observation systems.This procedure is used in seismic observation systems to select detected objects based on their location.
Keywords: seismic observation system; statistical hypothesis testing; likelihood ratio test; consistent detector; sequential Wald test
Analysis of reflected signals in testing cylindrical specimens by the multiple reflection echo-shadow method by O. V. Murav’eva; V. V. Murav’ev; M. A. Gabbasova; I. V. Buldakova; M. Yu. Sokov (367-373).
In this paper, we present the results of correlation, spectral, and probabilistic-statistical analyses of signals in the flaw inspection of cylindrical specimens by the multiple reflection echo-shadow method, and establish new informative parameters for the purpose of their integrated use to improve the reliability of nondestructive testing results.
Keywords: correlation; spectral; probabilistic-statistical analysis of signals; multiple reflection echoshadow control method; cylindrical specimen
Specific features of studying anisotropic media by methods of time-domain terahertz spectroscopy by V. D. Antsygin; V. F. Losev; A. A. Mamrashev; N. A. Nikolaev; O. I. Potaturkin (374-380).
Wide-band time-domain terahertz (THz) spectroscopy is a popular method of studying optical properties of various materials. This method is considered as applied to polarization-sensitive measurements of properties of anisotropic materials and media possessing significant dichroism and birefringence. It is important to understand that the development of the elemental base for the terahertz range, in particular, for THz polarizers, falls behind the achievements of polarization optics for the visible range. In studying anisotropic materials, this may lead to simultaneous detection of orthogonal components of the THz field and to formation of artifacts in the spectral range in calculations of properties of examined samples. A unique specific feature of time-domain terahertz spectroscopy, namely, a possibility of capturing the time-dependent shape of the THz pulse, allows separation of the orthogonal components of the field in the time domain. Thus, it is possible to detect the signal from radiation with the orthogonal polarization and eliminate it by means of appropriate adjustment of polarization elements of the spectroscopy system. This method is demonstrated by an example of studying the terahertz properties along the optical axis z of an anisotropic ferroelectric crystal of lead germanate in which significant birefringence and dichroism arise as the crystal is heated to the phase transition temperature.
Keywords: terahertz spectroscopy; terahertz radiation; polarization-optical detection; lead germanate; ferroelectric; dichroism; birefringence
Cell of the silicon integrated reading circuit with built-it analog-digital converter by A. V. Zverev; Yu. S. Makarov; E. A. Mikhant’ev; S. A. Dvoretskii (381-387).
This paper describes the project of an accumulative cell of a silicon integrated signal reading circuit with a built-in analog-digital converter for matrix IR photodetectors based on the Hg1-x CdxTe solid solutions with the sensitivity in the spectral range from 8 to 10 µm. The cell is designed according to the silicon technology HCMOS8D of JSC “NIIME i Mikron” (Moscow) with a project norm of 0.18 µm. The presented project of the cell has the size of 20×2020 µm, and the number of bits in the built-in analog-digital converter is 15. When the average photocurrent is 7 nA and the integration time is 7.5 ms, the estimated value of the noise equivalent delta temperature is 4.6 mK.
Keywords: integrated signal reading circuit; IR photodetectors; NETD; CMT; digital integration
Local electric fields in ensembles of composite nanoparticles by A. A. Zabolotskii (388-395).
Specific features of the formation of local fields in spherical composite nanoparticles containing metal cores surrounded by a silica shell with implanted dye molecules are studied. A system consisting of two closely located nanoparticles (dimers) is analyzed. It is shown that the field configuration in the dimer corresponds to a much more effective feedback than that in the case of individual spherical nanoparticles. The dynamics of the fluorescence field near a flat package of composite nanoparticles is studied numerically with due allowance for the enhancement of the dye fluorescence field, saturation of the energetic transition, and diffraction. It is found that close arrangement of nanoparticles leads under pumping conditions to the formation of high-intensity fields localized with time in the space of the nanoparticle package neighborhood.
Keywords: composite nanoparticles; local fields; laser therapy
Contactless measurement of electromagnetic parameters of nanomaterials by B. V. Skvortsov; D. M. Zhivonosnovskaya (396-403).
This paper describes the theoretical justification of operative contactless measurement of electromagnetic parameters of nanomaterials, based on probing of the controlled surface with an electromagnetic signal with subsequent processing of the reflected signal. The electromagnetic properties of these materials are determined by dielectric and magnetic permeability and specific electrical conductivity. The mathematical description of the measurement procedure is given, and the technique of search for the desired parameters based on measuring the amplitude and phase of the reflected signal with further solution of the nonlinear system of algebraic equations is developed.
Keywords: nanomaterials; conductivity; dielectric permeability; magnetic permeability; operational control; electromagnetic probing
Monochrome and two-color holograms in layered photopolymer materials by V. V. Shelkovnikov; E. V. Vasil’ev; V. V. Russkikh; L. V. Ektova; V. N. Berezhnaya; E. F. Pen (404-412).
The layered systems of holographic photopolymer materials for recording color holograms are designed and developed. Monochrome and two-color (green-red, red-blue, and green-blue) volume reflection holograms are obtained using the He—Ne, Ar+, and DPSS lasers in red, green, and blue spectral ranges. The effects of cross-bleaching of the dyes used and the holographic properties of monochrome and two-color holograms in layered systems are considered. It is shown experimentally that the diffraction efficiency of these holograms is ~(70–80%) and comparable with that of monochrome holograms obtained in single-layer holographic photopolymer materials.
Keywords: recording media; photopolymer materials; color holography
Limiting characteristics of a rotationally tunable two-beam interferometer with a fixed photosensitive element by V. D. Ugozhaev (413-420).
Results of calculations of the limiting characteristics of a rotationally tunable two-beam interferometer on the basis of a beam-splitter cube with fixed mirrors and a fixed photosensitive element are presented. The convergence angle is changed solely by rotating the beam source with respect to the interferometer. It is shown that the convergence angle can be varied in the interval from 46 to 166° with sufficiently wide light beams.
Keywords: two-beam interferometer; beam-splitter cube; fixed mirrors; fixed photosensitive element; rotational adjustment of the convergence angle; multidimensional periodic structure