One of the simplest algorithms for adaptive correction (correction of a random tilt of a wavefron... more One of the simplest algorithms for adaptive correction (correction of a random tilt of a wavefront) is considered in the case of a wide optical beam when a point reference source is used. An analysis is made of various algorithms for the determination of a random tilt. A ...
An analysis is made of the problem of improving the quality of an image of a coherent extended ob... more An analysis is made of the problem of improving the quality of an image of a coherent extended object formed by an optical system after transmission through the atmosphere. The problem is tackled by adaptive correction. The correction is carried out in accordance with a phase conjugacy algorithm and information on the distribution of turbulent inhomogeneities of the medium (atmosphere) in the propagation path of light is deduced from measurements of the phase of the field of a reference source. Characteristics of an optical adaptive correction system, such as the optical transfer function and resolution, are considered.
An analysis is made of the possibility of correction of random angular displacements of the energ... more An analysis is made of the possibility of correction of random angular displacements of the energy center of gravity of an optical beam (traveling in a turbulent atmosphere) by tracking the random angular position of the center of gravity of the image of a reference beam. The ...
Frequency estimation of complex sinusoidal signal parameters for mixed Gaussian and impulse noise... more Frequency estimation of complex sinusoidal signal parameters for mixed Gaussian and impulse noise environment is considered. We assume that the sinusoid has constant amplitude. The first stage in the proposed algorithm is calculation of the L-DFT forms for various parameters. Then, an optimal value of the L-DFT parameter is estimated as a value minimizing the L-DFT energy. Position of the L-DFT maximum calculated for the optimal parameter is used as a coarse frequency estimate. Fine estimation is performed by a recently proposed iterative procedure. Numerical analysis confirms accuracy of the proposed technique.
This paper deals with theoretical and numerical simulation based analysis of sample myriad proper... more This paper deals with theoretical and numerical simulation based analysis of sample myriad properties for a family of symmetric α-stable (SαS) distributions often used for modeling noise in natural environments. The theoretically optimal values of a sample myriad tunable parameter k in the sense of minimal asymptotic variance are obtained. Two practical approaches are proposed to adapt the parameter k to SαS distribution characteristics for data samples of a limited size. Statistical properties of the developed approaches are studied for cases of a priori unknown parameters of SαS distribution. A practical application where the proposed approaches can be useful is considered.
Noise is one of the basic factors that degrade remote sensing (RS) data and prevent accurate and ... more Noise is one of the basic factors that degrade remote sensing (RS) data and prevent accurate and reliable retrieval of useful information. Availability of a priori information on noise type and properties allows applying more effective methods for image processing, ...
Abstract Several simplest variants of application of adaptive control of the parameters of a beam... more Abstract Several simplest variants of application of adaptive control of the parameters of a beam are suggested. They are based on the application of the principle of reciprocity of propagation of radiation in an inhomogeneous medium. Information on the necessary ...
A theoretical analysis is made of the efficiency of a system for the compensation of phase fluctu... more A theoretical analysis is made of the efficiency of a system for the compensation of phase fluctuations of an optical wave traveling in a turbulent atmosphere. In this system the distortions are compensated on the basis of measurements of phase fluctuations in the ...
Thermal-blooming correction can reduce high-power laser beam distortions in the atmosphere. We us... more Thermal-blooming correction can reduce high-power laser beam distortions in the atmosphere. We use computer simulations to estimate the efficiency of different phase and amplitude-phase correction algorithms over horizontal and vertical atmospheric paths.
International Conference on Acoustics, Speech, and Signal Processing, 2006
Abstract This paper deals with the problem of identifying the nature of the noise and estimating ... more Abstract This paper deals with the problem of identifying the nature of the noise and estimating its statistical parameters from the observed image in order to be able to apply the most appropriate processing or analysis algorithm afterwards. We focus our attention on ...
One of the simplest algorithms for adaptive correction (correction of a random tilt of a wavefron... more One of the simplest algorithms for adaptive correction (correction of a random tilt of a wavefront) is considered in the case of a wide optical beam when a point reference source is used. An analysis is made of various algorithms for the determination of a random tilt. A ...
An analysis is made of the problem of improving the quality of an image of a coherent extended ob... more An analysis is made of the problem of improving the quality of an image of a coherent extended object formed by an optical system after transmission through the atmosphere. The problem is tackled by adaptive correction. The correction is carried out in accordance with a phase conjugacy algorithm and information on the distribution of turbulent inhomogeneities of the medium (atmosphere) in the propagation path of light is deduced from measurements of the phase of the field of a reference source. Characteristics of an optical adaptive correction system, such as the optical transfer function and resolution, are considered.
An analysis is made of the possibility of correction of random angular displacements of the energ... more An analysis is made of the possibility of correction of random angular displacements of the energy center of gravity of an optical beam (traveling in a turbulent atmosphere) by tracking the random angular position of the center of gravity of the image of a reference beam. The ...
Frequency estimation of complex sinusoidal signal parameters for mixed Gaussian and impulse noise... more Frequency estimation of complex sinusoidal signal parameters for mixed Gaussian and impulse noise environment is considered. We assume that the sinusoid has constant amplitude. The first stage in the proposed algorithm is calculation of the L-DFT forms for various parameters. Then, an optimal value of the L-DFT parameter is estimated as a value minimizing the L-DFT energy. Position of the L-DFT maximum calculated for the optimal parameter is used as a coarse frequency estimate. Fine estimation is performed by a recently proposed iterative procedure. Numerical analysis confirms accuracy of the proposed technique.
This paper deals with theoretical and numerical simulation based analysis of sample myriad proper... more This paper deals with theoretical and numerical simulation based analysis of sample myriad properties for a family of symmetric α-stable (SαS) distributions often used for modeling noise in natural environments. The theoretically optimal values of a sample myriad tunable parameter k in the sense of minimal asymptotic variance are obtained. Two practical approaches are proposed to adapt the parameter k to SαS distribution characteristics for data samples of a limited size. Statistical properties of the developed approaches are studied for cases of a priori unknown parameters of SαS distribution. A practical application where the proposed approaches can be useful is considered.
Noise is one of the basic factors that degrade remote sensing (RS) data and prevent accurate and ... more Noise is one of the basic factors that degrade remote sensing (RS) data and prevent accurate and reliable retrieval of useful information. Availability of a priori information on noise type and properties allows applying more effective methods for image processing, ...
Abstract Several simplest variants of application of adaptive control of the parameters of a beam... more Abstract Several simplest variants of application of adaptive control of the parameters of a beam are suggested. They are based on the application of the principle of reciprocity of propagation of radiation in an inhomogeneous medium. Information on the necessary ...
A theoretical analysis is made of the efficiency of a system for the compensation of phase fluctu... more A theoretical analysis is made of the efficiency of a system for the compensation of phase fluctuations of an optical wave traveling in a turbulent atmosphere. In this system the distortions are compensated on the basis of measurements of phase fluctuations in the ...
Thermal-blooming correction can reduce high-power laser beam distortions in the atmosphere. We us... more Thermal-blooming correction can reduce high-power laser beam distortions in the atmosphere. We use computer simulations to estimate the efficiency of different phase and amplitude-phase correction algorithms over horizontal and vertical atmospheric paths.
International Conference on Acoustics, Speech, and Signal Processing, 2006
Abstract This paper deals with the problem of identifying the nature of the noise and estimating ... more Abstract This paper deals with the problem of identifying the nature of the noise and estimating its statistical parameters from the observed image in order to be able to apply the most appropriate processing or analysis algorithm afterwards. We focus our attention on ...
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Papers by Vladimir Lukin