СЕГМЕНТАЦИЯ ИЗОБРАЖЕНИЙ И СЕЛЕКЦИЯ ОБЪЕКТОВ НА ОСНОВЕ МНОГОПОРОГОВОЙ ОБРАБОТКИ

Introduction. In order to automate data processing in remote observation systems using television and infrared cameras, synthetic aperture panoramic radars, as well as laser and acoustic systems, it is essential to be able to reliably detect, isolate, select and localise objects of various shapes in images. Objective. The development of a methodology based on multi-threshold analysis. Materials and methods. The developed image segmentation and object selection approach having optimal selection threshold assessment is based on the results of multi-threshold image analysis. Results. Based on the analysis of a series of standard objects with known shapes hindered by synthetic noise, as well as representative examples of remotely sensed images of the Earth’s surface, improvements in the characteristics of both entire image segmentation and selection of particular objects according to several objective criteria were achieved.Conclusion. The main advantage of the proposed approach consists in the minimisation of the post-processing shape modification of the selected objects. Although this is achieved at the cost of the resource-consuming multi-threshold analysis procedure for each processed image, this can be also partially compensated by the simplicity of the algorithm and its possible parallel implementation.Введение. Задачи обнаружения, выделения, селекции и локализации объектов различной формы на изображениях неразрывно связаны с автоматизацией обработки информации в системах дистанционного наблюдения, использующие телевизионные и инфракрасные камеры, обзорные радиолокаторы с синтезированной апертурой, лазерные и акустические системы. Цель работы. Разработка методики сегментации изображений и селекции объектов на них на основе многопороговой обработки. Материалы и методы. Предложен подход к сегментации изображений и селекции объектов на них, основанный на выборе оптимального селектирующего порога с использованием апостериорной информации о результатах многопороговой обработки изображения.Результаты. По результатам анализа серий модельных объектов заранее известной формы в условиях добавления синтезированного шума, а также репрезентативных примеров реальных изображениях, полученных при дистанционном зондировании поверхности Земли, показано, что за счет использования результатов многопороговой обработки удается улучшить характеристики как сегментации изображения в целом, так и селекции объектов по ряду объективных критериев. Заключение. К достоинствам предложенного подхода следует отнести минимизацию искажений формы селектируемых объектов в ходе обработки изображения. Платой за это является ресурсоемкость процедуры многопороговой обработки для каждого анализируемого изображения, что отчасти может быть компенсировано простотой алгоритма и возможностью его параллельной реализации

Ring-Shaped Sensitive Element Design for Acceleration Measurements: Overcoming the Limitations of Angular-Shaped Sensors

A new modification of an acceleration measurement sensor based on an acoustic waves resonance principle is proposed. Common angular-shaped sensors exhibit stress concentrations at the angular points near the origin points of destruction under external stresses; these points are the “Achilles’ heel„ of the entire design. To overcome the above limitation, we suggest an angular-free ring-shaped sensitive element design that is characterized by enhanced robustness against external stress. The analytical treatment is validated by computer simulation results performed using the COMSOL Multiphysics software package. For an appropriate model parameterization, an original experiment has been carried out to estimate the stress-strained robustness of two potential candidates for sensitive console materials. Moreover, characteristics of the proposed sensor design, such as sensitivity threshold and maximum stress, have been obtained from the simulation data. The above results indicate that the proposed concept offers a promising advancement in surface acoustic waves (SAW) based accelerometer devices, and could, therefore, be used for several practical applications in such areas as biomedical and sports wearable devices; vehicular design, including unmanned solutions; and industrial robotics, especially those where high-G forces are expected

IMAGE SEGMENTATION AND OBJECT SELECTION BASED ON MULTI-THRESHOLD PROCESSING

Introduction. In order to automate data processing in remote observation systems using television and infrared cameras, synthetic aperture panoramic radars, as well as laser and acoustic systems, it is essential to be able to reliably detect, isolate, select and localise objects of various shapes in images. Objective. The development of a methodology based on multi-threshold analysis. Materials and methods. The developed image segmentation and object selection approach having optimal selection threshold assessment is based on the results of multi-threshold image analysis. Results. Based on the analysis of a series of standard objects with known shapes hindered by synthetic noise, as well as representative examples of remotely sensed images of the Earth’s surface, improvements in the characteristics of both entire image segmentation and selection of particular objects according to several objective criteria were achieved.Conclusion. The main advantage of the proposed approach consists in the minimisation of the post-processing shape modification of the selected objects. Although this is achieved at the cost of the resource-consuming multi-threshold analysis procedure for each processed image, this can be also partially compensated by the simplicity of the algorithm and its possible parallel implementation

Comparison of AlN vs. SIO2/LiNbO3 Membranes as Sensitive Elements for the SAW-Based Acceleration Measurement: Overcoming the Anisotropy Effects

We propose the use of aluminum nitride (AlN) membranes acting as sensitive elements for the surface acoustic wave (SAW)-based acceleration measurement. The proposed solution is compared against existing prototypes based on the use of quartz (SiO2)/lithium niobate (LiNbO3) membranes that are characterized by extensive anisotropic properties. Using COMSOL Multiphysics 5.4 computer simulations we show explicitly that sensitive elements based on less anisotropic AlN membranes overcome both the low sensitivity limitations of SiO2 and low temperature stability of LiNbO3. Moreover, AlN membranes exhibit nearly double the robustness against irreversible mechanical deformations when compared against SiO2, which in turn allows for further 1.5-fold sensitivity enhancement over LiNbO3 based sensors. Taking into account their acceptable frequency characteristics, we thus believe that the AlN membranes are a good candidate forsensitive elements especially for high acceleration measurements

On Sea Ice Measurement by a C-Band Scatterometer at VV Polarization: Methodology Optimization Based on Computer Simulations

We consider sea ice and water microwave backscatter features at the C-band with vertical transmit and receive polarization and present a method for sea ice/water discrimination using a multiple fixed fan-beam satellite scatterometer. The method is based on the criterion of the minimum statistical distance of measured backscatter values to the sea ice and water (CMOD7) geophysical model functions. Implementation of the method is considered both for a typical three fan-beam geometry as well as for a potential five fan-beam geometry of a satellite scatterometer. By using computer simulations, we show explicitly that the number of looks at the same cell from different azimuthal directions needs to be increased to provide better (unambiguous) retrieval of the wind vector and sea ice/water discrimination. The algorithms for sea ice/water discrimination are described, and the results obtained are also discussed along with recommendations for the number of different azimuthal looks (beams) at the same cell from the point of view of sea ice/water discrimination as well as unambiguous wind direction retrieval during the satellite’s single pass

Comparison of Structure and Local Dynamics of Two Peptide Dendrimers with the Same Backbone but with Different Side Groups in Their Spacers

In this paper, we perform computer simulation of two lysine-based dendrimers with Lys-2Lys and Lys-2Gly repeating units. These dendrimers were recently studied experimentally by NMR (Sci. Reports, 2018, 8, 8916) and tested as carriers for gene delivery (Bioorg. Chem., 2020, 95, 103504). Simulation was performed by molecular dynamics method in a wide range of temperatures. We have shown that the Lys-2Lys dendrimer has a larger size but smaller fluctuations as well as lower internal density in comparison with the Lys-2Gly dendrimer. The Lys-2Lys dendrimer has larger charge but counterions form more ion pairs with its NH 3 + groups and reduce the bare charge and zeta potential of the first dendrimer more strongly. It was demonstrated that these differences between dendrimers are due to the lower flexibility and the larger charge (+2) of each 2Lys spacers in comparison with 2Gly ones. The terminal CH2 groups in both dendrimers move faster than the inner CH2 groups. The calculated temperature dependencies of the spin-lattice relaxation times of these groups for both dendrimers are in a good agreement with the experimental results obtained by NMR

Optimization of airborne antenna geometry for ocean surface scatterometric measurements

We consider different antenna configurations, ranging from simple X-configuration to multi-beam star geometries, for airborne scatterometric measurements of the wind vector near the ocean surface. For all geometries, track-stabilized antenna configurations, as well as horizontal transmitter and receiver polarizations, are considered. The wind vector retrieval algorithm is generalized here for an arbitrary star geometry antenna configuration and tested using the Ku-Band geophysical model function. Using Monte Carlo simulations for the fixed total measurement time, we show explicitly that the relative wind speed estimation accuracy barely depends on the chosen antenna geometry, while the maximum wind direction retrieval error reduces moderately with increasing angular resolution, although at the cost of increased retrieval algorithm computational complexity, thus, limiting online analysis options with onboard equipment. Remarkably, the simplest X-configuration, while the simplest in terms of hardware implementation and computational time, appears an outlier, yielding considerably higher maximum retrieval errors when compared to all other configurations. We believe that our results are useful for the optimization of both hardware and software design for modern airborne scatterometric measurement systems based on tunable antenna arrays especially, those requiring online data processing

Size and Structure of Empty and Filled Nanocontainer Based on Peptide Dendrimer with Histidine Spacers at Different pH

Novel peptide dendrimer with Lys-2His repeating units was recently synthesized, studied by NMR (Molecules, 2019, 24, 2481) and tested as a nanocontainer for siRNA delivery (Int. J. Mol. Sci., 2020, 21, 3138). Histidine amino acid residues were inserted in the spacers of this dendrimer. Increase of their charge with a pH decrease turns a surface-charged dendrimer into a volume-charged one and should change all properties. In this paper, the molecular dynamics simulation method was applied to compare the properties of the dendrimer in water with explicit counterions at two different pHs (at normal pH with neutral histidines and at low pH with fully protonated histidines) in a wide interval of temperatures. We obtained that the dendrimer at low pH has essentially larger size and size fluctuations. The electrostatic properties of the dendrimers are different but they are in good agreement with the theoretical soft sphere model and practically do not depend on temperature. We have shown that the effect of pairing of side imidazole groups is much stronger in the dendrimer with neutral histidines than in the dendrimer with protonated histidines. We also demonstrated that the capacity of a nanocontainer based on this dendrimer with protonated histidines is significantly larger than that of a nanocontainer with neutral histidines

High Precision Human Skin Temperature Fluctuations Measuring Instrument

This paper describes the experimental results of testing a prototype of a high precision human skin rapid temperature fluctuations measuring instrument. Based on the author’s work, an original circuit solution on a miniature semiconductor diode sensor has been designed. The proposed circuitry provides operation in the full voltage range with automatic setting and holding the operating point, as well as the necessary slope of the conversion coefficient (up to 2300 mV/°C), which makes it possible to register fast temperature oscillations from the surface of the human body and other biological objects. Simulation results in the Microcap 12 software and laboratory tests have confirmed all declared design specifications: temperature resolution of 0.01 °C, transducer thermal time constant of 0.05 s. An original thermostat and an experimental setup for the simultaneous registration of the electrocardiogram, pulse wave signals from the Biopac polygraph MP36 and a signal of temperature oscillations from the prototype thermometer have been designed for further investigations. The preliminary test results indicates that using the designed measuring instrument gives a possibility to provide an in-depth study of the relationship between micro- and macro-blood circulations manifested in skin temperature fluctuations