Introduction. When developing and testing high-speed communication links of digital electronic devices, the pulse shape of electrical signals and interference in transmission lines is commonly controlled using eye diagrams. Partial pulse responses are estimated by modern multi-channel testing and measuring equipment using specific testing procedures. Aim. To develop an approach to blind identification of a wireline communication signal measured by a digital oscilloscope in microstrip transmission lines.

Materials and methods. The study was carried out using a communication signal model composed of a superposition of the information signal, intersymbol interference, and crosstalk interference from an adjacent transmission line, with the symbols of these signal sources being assumed statistically independent. The implemented blind identification method makes it possible to separate three components of the signal and evaluate their partial pulse responses. The proposed procedure for signal separation includes preliminary processing of the data measured by principal component analysis followed by an analysis of independent components based on fourth-order statistical characteristics.

Results. The performance of the proposed signal separation method is demonstrated using the results of parallel and independent data processing measured in microstrip transmission lines in an experimental setup with two closely spaced printed circuit boards. A comparison of blind signal separation methods is carried out based on second-order statistics, fourth-order cumulants, and independent component analysis. The proposed method of independent component analysis demonstrated the highest efficiency in terms of minimum bit error probability for blind signal separation with arbitrary partial pulse responses, which was confirmed by simulation results.

Conclusion. The developed approach to blind identification of wireline signal parameters measured in high-density integrated digital electronic devices extends the range of systems for circuit design and testing of multi-channel high-speed communication lines.

Introduction. At present, automatic capture and tracking of moving objects in video data obtained by a video camera mounted on a mobile carrier represents a relevant research task. Its successful solution is challenged by such factors, as a non-uniform background, object overlapping between one another and the background, significant and rapid changes in the size of the object of interest, abrupt changes in the movement trajectory of the mobile carrier.

Aim. To develop an automatic method for detecting moving objects followed by their tracking in video data obtained under difficult observation conditions. An additional requirement imposed on the tracking stage consists in the restriction of computing resources.

Materials and methods. The method is based on a convolutional neural network with a YOLO architecture. Due to the restriction of computing resources, object tracking is implemented without neural network solutions. In order to ensure stable tracking, several detectors are used simultaneously with the subsequent analysis of the data obtained. The tracking stage involves a detector based on histograms of oriented gradients (HOG), supplemented by a detector based on correlation filtering and motion trajectory prediction based on the Kalman filter.

Results. At the automatic detection stage, the TPR, averaged over all video files participating in the experiments, was equal to 0.81, with the FPR corresponding to 0.10. At the tracking stage, the failure rate (tracking failures) was 6·10 ^–5.

Conclusion. The proposed method can be successfully used to detect and track objects at a distance of 1500 m with an object projection size on the frame of 5 × 5 pixels under the conditions of global motion, a non-uniform background, and significant changes in the properties of the object of interest.

Introduction. Remote sensing and monitoring of the sea surface are of great importance in such fields, as operational oceanography, environmental monitoring, etc. The ability to quickly assess the state of the sea surface is particularly relevant in areas that pose a danger to shipping, where rapid and accurate response becomes critical. Modern radars represent information as digital image series largely reminiscent to a frame series in a video stream, thus enabling the use of gradient methods originally designed for and proven successful in video analysis.

Aim. Determination of sea wave characteristics from radar images using gradient motion estimation methods. The use of gradient methods will allow implementing additional tools for processing radar image series obtained from sea backscatter.

Materials and methods. To assess the characteristics of the sea surface from radar images, gradient methods were used. To train the methods, a series of synthetic images of the sea surface obtained by mathematical modeling were used. To evaluate the effectiveness of the gradient methods, two representative experimental radar image series provided by the Institute of Oceanography RAS were employed.

Results. Using gradient methods, the direction and speed of waves were calculated from several consecutive radar observations. Regression models of the dependence of calculated values on the specified ones were constructed. The Farneback and TV-L1 methods proved to be effective especially for obtaining the direction of the sea waves.

Conclusion. An algorithm for evaluating speed and direction of the sea surface displacement using gradient methods was pre-trained using simulated model data. The implemented methods and algorithms for assessing the speed and direction of sea waves were validated using two experimental image series obtained from shipborne navigational radars.

Introduction. The existing CAD tools of electrodynamic modeling used to analyze complex waveguide structures of the microwave range employ the finite element method. However, in the terahertz range, determining the channeling properties of layered dielectric waveguides becomes a difficult task. This is primarily related to the construction of a partition grid of the layered structure and the need to take into account the behavior of the electromagnetic field at the boundaries of media with different relative permittivity. In this work, we use the principles of the finite element method to solve the problem of finding a propagation constant in a flat multilayer dielectric waveguide, and show how to reduce the number of elements when setting optimal boundary conditions. Based on the obtained computational model, the possibility of constructing diffraction antennas operating in the THz range is considered.

Aim. Construction of a computational model for calculating a flat dielectric waveguide by the finite element method, determination of the dispersion characteristics of the analyzed structure in the THz range. Discussion of the possibility of constructing a diffraction antenna on a dielectric structure in various designs.

Materials and methods. A computational mathematical model for the analysis of a complex layered structure is based on Maxwell's equations and the finite element method using boundary conditions for tangential and normal components of the electromagnetic field.

Results. A numerical analysis of the dispersion characteristics of structures with complex dielectric filling is carried out; variants of diffraction antennas for use in the THz range are considered.

Conclusion. The created mathematical models made it possible to numerically evaluate the channeling properties of dielectric structures in the THz range, on the basis of which diffraction antennas can be constructed.

Introduction. The use of spintronic components significantly enhances the performance, reduces the size, and lowers the power consumption of modern electronic devices. The spintronic oscillator (SO) is an integral part of spintronic devices. Connecting several SOs (> 100) into ensembles with subsequent synchronization mitigates such SO drawbacks as low output power and high phase noise. These drawbacks appear as a result of an increase in the output power of an SO ensemble compared to a single oscillator under a simultaneous decrease in the spectral linewidth of the ensemble.

Aim. To investigate the impact of connection topologies, synchronization mechanisms, and oscillator failures on the synchronization of oscillator ensembles.

Materials and methods. The Kuramoto phase model was used to simplify the numerical modeling of synchronization of SOs connected into an ensemble.

Results. A Kuramoto equation for phases of SOs connected in an ensemble was derived, and the influence of connection topologies and oscillator failures on the synchronization parameters of an ensemble of N connected oscillators was demonstrated.

Conclusion. In order to ensure the shortest transition time of an SO ensemble to the synchronous mode, topologies with a higher number of connections between oscillators (e.g., "all-to-all") are preferable. The results obtained confirm the advantages of local connection of an SO ensemble by a common current, thus forming an "all-to-all" topology. This makes the transition time of the SO ensemble to the synchronous mode less dependent on both oscillator failures and the number of synchronized SOs.

Introduction. Recent developments in the field of thermal imaging technology and the accumulated experience in instrumental analysis of thermal processes in the patient’s body indicate the prospects of developing new medical thermal imaging systems (thermal imagers).

Aim. Creation of a low-budget domestic thermal imaging system for medical diagnostics with expanded functionality.

Materials and methods. The distribution of temperature over the surface of the human body depends on its internal state and external environment. For each person, this distribution has its own physiological characteristics, the study and interpretation of which can be significant for diagnosing specific pathologies or assessing the general (psychophysical) state of the patient. Analysis of temperature fields on the surface of the human body makes it possible to diagnose various pathological processes manifested in the form of local temperature changes in individual areas. The proposed method for thermal diagnostics involves measuring the temperature at each point of such an area simultaneously (statically) or over a period of time (dynamically). In comparison with conventional approaches, two thermal imaging sensors are used for this purpose. These include a small-sized matrix (thus being low cost) and a point sensor. Such a combination of sensors provides for the necessary discretization of the temperature field image of sufficiently large areas of the surface of the human body, when shooting from a distance significantly reduced compared to the conventional approach.

Results. A conceptual electrical circuit and a layout of a modern thermal imaging system are developed. The advantages of the proposed thermal imager over similar devices are assessed. A method for recording and analyzing temperature in a certain point and temperature fields of both separate areas and large areas on the surface of the human body is proposed and tested.

Conclusion. The conducted testing of a material model of the proposed thermal imaging system using the facilities of large medical institutions in St. Petersburg showed its wide functionality along with simplicity and convenience.

Introduction. An approach to designing a gyroscopic inclinometer (GI) based on a single uniaxial angular rate sensor (ARS) is developed. It is argued that such an ARS should be considered a modification of a longitudinal GI scheme, preserving the well-known disadvantages of its performance characteristics. The latter include a lack of adaptability to the trajectory, i.e., commensurability of GI errors at different zenith angles. This work sets out to develop a scheme with one ARS in order to achieve a multiple increase in the accuracy of azimuth measurements for vertical and adjacent-to-the-vertical boreholes when the GI is operated in continuous mode.

Aim. To make a GI based on a uniaxial angular velocity sensor more adaptive to the borehole trajectory thought its design modification and a comparative analysis of errors.

Materials and methods. Algorithms for ideal operation of the proposed scheme in continuous mode are synthesized based on matrix transformations of coordinates and Euler equations. The properties of orientation errors are examined using linearization methods, integral calculus, fundamentals of the calculus of variations, and the theory of linear differential equations.

Results. The adaptivity of the modified GI scheme to the borehole trajectory was achieved by means of a structurally provided deviation of the ARS sensitivity axis by a certain angle of non-orthogonality to the GI longitudinal axis. When designing a GI based on the developed approach, it is possible to realize the value of this angle of 20°. For this angle, the increase in the compassing error does not exceed the uncertainty of the ARS drift statistical characteristics, while achieving an effective level of adaptivity to the borehole trajectory in continuous mode.

Conclusion. The developed scheme makes it possible to significantly reduce the influence of the ARS drift on the accuracy of azimuth calculation in the transitional zenith angles area (from vertical to directional boreholes) in comparison with the well-known longitudinal scheme, thereby maintaining an increased initial azimuth accuracy during movement in the initial alignment at the wellhead.

Introduction. Formation of a contact surface in prosthetics and orthotics is crucial for the restoration of human musculoskeletal functions. This paper considers specific features of methods currently used for denoising of a 3D model surface obtained by optical scanning. An algorithm for manufacturing an individual prosthetic and orthopedic product is developed. The current literature reports no similar methods, which may be explained by the widespread use of gypsum technology for the manufacture of prostheses and orthoses.

Aim. Research and development of digital filtration methods for 3D meshes obtained by optical scanning for further modeling of individual prosthesis and orthosis modules.

Materials and methods. It is proposed to optimize the pre-processing stage of 3D scanned models by applying denoising and smoothing processes. In total, 50 optical 3D scans were selected for testing via the following denoising algorithms: bilateral filtering, vertex-based anisotropic smoothing, mean and median filtering applied to face normals.

Results. The study was conducted using 3D scans of lower limb stumps and Chenault brace orthoses and corsets provided by the Institute of Prosthetics and Orthotics, Albrecht Federal Scientific and Educational Centre of Medical and Social Expertise and Rehabilitation. А method for denoising and smoothing of the 3D model surfaces for the manufacture of prosthetic and orthopedic products is proposed. The SNR metric difference SNR – δ-SNR (with averaging by scans and SNR values) and average execution time were calculated. The bilateral filtration method with δ-SNR = 11.3362 dB and a runtime of 8.8900 s showed the highest efficiency.

Conclusion. The proposed methods for the pre-processing stage of 3D optical scans showed high efficiency in the formation of 3D models of prosthesis and orthosis modules. The results obtained can be used for automating the process of manufacturing various prosthetic and orthopedic products, which is particularly relevant in the context of the modern geopolitical situation.

Introduction. Environmental monitoring of marine areas and timely detection of the results of man-made disasters on the water surface, including identification of oil contaminated areas, represents an urgent task. To facilitate its solution, marine areas are controlled using space and airborne means. However, the volume of data subject to control is constantly growing. Therefore, the problem can be solved by selecting only those photo and video materials with detected traces of oil spills and other man-made disasters.

Aim. To develop an approach to automatic selection of images obtained from visual control systems, providing only relevant images.

Materials and methods. The theoretical part of the study was carried out using a classification method based on pattern recognition theory. A test image with an oil spill on the surface of the Black Sea was compared with the same image presented in BMP format with different color depth encodings, as well as with the same image presented in JPEG format. Raster images were processed using a specialized software application. Simulation was carried out in the MathCAD environment.

Results. The developed approach was tested experimentally by processing 200 images. The conducted visual analysis confirmed that the image, where the given boundary allows the area of oil spill to be clearly distinguishes, is the closest to the test image.

Conclusion. According to the results of the experiment with different formats of raster image files, the conclusion is made about the feasibility of using images obtained by visual control systems presented in JPEG format as initial data. Further research directions are outlined.