Home – Home – Jornals – Avtometriya 2018 number 3

This paper describes the problem of thematic processing of hyperspectral aerospace images. The proposed technique is based on a decoding algorithm, allows constructing an effective algorithm of multiclass classification based on a combination of standard algorithms of binary classification of various complexity. The choice of the configuration of the classification algorithm is substantiated. Test calculations based on model and real data are used to show the effectiveness of the proposed approach to recognition of objects by hyperspectral images.

This paper describes a PlanetaMonitoring software complex, developed jointly by the Scientific Research Center “Planeta” and the Institute of Computational Mathematics and Mathematical Geophysics of the Siberian Branch of the Russian Academy of Sciences, which implements the software technologies of pre-processing and thematic processing of multizone satellite images of optical, infrared, and microwave ranges. This work also touches upon the use of some technologies of pre-processing of satellite data, particularly brightness and geometric transformations, geocoding, and compilation of survey installation. Thematic processing of multizone satellite images by software technologies for object recognition (without and with learning), allocation and mapping of lineaments and ring structures, as well as determining the spatial movement of natural objects (ice fields, water masses, and cloud formations in the atmosphere) over time-different satellite images is described. These software technologies are used in solving a number of applied problems of Earth remote sensing.

A panoramic aerial photograph composed of a series of consecutive images obtained from a pilotless aircraft allows for more accurate recognition of visual objects. Automatic joining of aerial photographs is a complex technical problem, especially in the presence of artefacts of the recording equipment and video-recording conditions. It is believed that a sequence of joined images is known and determined by the flight trajectory. The proposed method for joining aerial photographs is based on illumination levelling and multiband mixing. The possibilities of application of SURF, FAST, FAST-ER, and KAZE point descriptors for joining images are studied. It is shown that the point descriptors on the basis of nonlinear diffuse filtering yield the best results with regard to accuracy in the presence of global and/or local visual distortions of joined images.

The application of signal energy parameters to estimate the motion of objects with continuous influence on soil in systems of passive seismic location is considered. Statistics for measured values of signal powers with account for energy properties of the medium are proposed. The influence of displacement of the object on the ratio of signal powers on different sensors is analyzed. The results of testing the algorithm for estimating the parameters of the trajectory of rectilinear motion of a car are given.

This paper touches upon the experience of research and development of software and hardware for monitoring atmospheric pollution of industrial cities, carried out at the Institute of Computational Modeling of the Siberian Branch of the Russian Academy of Sciences. Functional possibilities, architectural features, and user interface of the distributed geoinformation web-system of ecological monitoring of the city of Krasnoyarsk, which is being developed in service-oriented architecture, are discussed. Data are collected from automated posts for observing the state of atmospheric air and services of aggregation and representation of information in the form of interactive graphs and thematic maps in the web interface. An original device is developed for measuring the pollution level of the atmosphere with fine dust (PM2.5), the data from which is fed in real time to the system via a cellular network. A system is formed for integral assessment of the pollution level of the atmosphere based on Atmospheric Quality Index (AQI) calculations.

Scanning devices based on a set of mutually biased photodetector arrays require a high degree of stabilization of the scan speed to increase the sampling rate in a direction orthogonal to the scanning direction for high quality of the image being formed. A new method is proposed for estimating the scanning rate, based on the analysis of displacements of images of arbitrary random texture created by arrays during scanning. The dependence of the accuracy of various methods of speed estimation on the statistical characteristics of the texture is studied by simulation. It is shown that even at a sufficiently high level of random noise (C/N =10) even for images with texture that satisfied the Nyquist criterion for each array, the scan speed estimation error does not exceed 0.1 % of the nominal value.

The representation of measurement data as a bit space is considered. A method and an algorithm for reversible geometric compression of measurement data frames are proposed based on their transformation to a bit-like form with the subsequent mapping onto a plane and division into strictly homogeneous regions. Experimental results showing that the proposed algorithm provides high overall compression efficiency are presented.

An algorithm for automatically recognizing the type of dynamic object detected by an optoelectronic device with an a priori uncertainty about the current background situation is proposed. Recognition is carried out from samples of statistics in the form of energies of wavelet spectra of the coordinates of the elevation angle, azimuth, and calculated maximum distance of the detected object. The recognition criterion is unbiased and the most powerful. Modeling has shown that the algorithm is highly efficient and implementable in real time on modern PC.

The reconstruction of an image of the section of a thin wire, obtained by an ultrasonic locator in an aqueous medium at frequency of 1.3 MHz with a monochromatic sounding signal is considered. Reconstruction of the image was carried out using a synthesized aperture by correlation processing of the trajectory Doppler signal with calculated reference trajectory signals from point objects. The disturbing effect of the reflected ultrasonic wave from the surface wave left by the moving wire on the image reconstruction is taken into account. The results of reconstruction of the image of the wire cross-section from model and experimental trajectory signals in the presence of a surface wave are given.

The contrast of a combination of two image plans spaced along the visual axis of the eye to stimulate the accommodation in 3D displays is analyzed. Two methods of normalization based on individual and group calculations of optimal coefficients of combinations for different diameter of the pupil of the eye at specified image resolution are proposed.

A spectral method of detection of laser Doppler velocimeter signals in turbulent flows is proposed. The method is based on estimating the signal/noise ratio adapted to the width of the signal power spectral density and comparing its value with the recognition threshold. Numerical simulations show that the error of the signal/noise ratio estimates is 1 % for different velocities of the turbulent flow. Physical experiments aimed at measuring turbulent aerodynamic processes show that the proposed method offers a possibility of eliminating the errors of calculating the mean value and the velocity scatter equal to 15 and 78 % by means of eliminating the signals with low signal/noise ratios from the processing system. Application of the proposed method also ensures lower irregularity of the signal/noise ratio estimates than that ensured by the famous method developed by Tropea for a wide range of turbulent velocities.

A mathematical model is developed for calculating the beating noise that occurs during photodetection of a single-band optical OFDM signal. The model allows one to estimate the spectral distribution of the beating noise and the distortion of the OFDM signal subcarrier levels due to fiber dispersion. The influence of the beating noise on orthogonal subcarrier channels, possible ways of increasing the system transmission capacity, and the method of noise compensation on the receiving side are investigated.

A new method of increasing the spatial resolution in digital holographic microscopy is considered. The method is based on supplementing the initial hologram with results measured in the case of photodetector shifting in space by a value smaller than the resolution used. In contrast to other known approaches, this method does not require a system of equations to be solved.

Deformation of the spectrum of the D₁ line of ⁸⁵Rb in optical cells with an anti-reflection coating on the inner walls of the cell is studied. The spectrum shape is found to be significantly dependent on the velocity and direction of changes in the laser frequency. A physical explanation is provided for these features, which are confirmed by numerical simulations. The effect of the magnetic field on the spectrum shape is discussed.

Control methods with the use of two deformable mirrors (correcting aberrations of high and low spatial frequencies, respectively) are briefly described. Results of preliminary experiments aimed at developing algorithms for deformable mirror control are reported.