Optical-electronic System Research Articles

Optical and Electronic Expert System for Diagnosing Eye Pathology in Glaucoma

For the first time, mathematical models for evaluating biomedical images were obtained using fuzzy set methods on the basis of expert knowledge bases, thus making it possible to carry out complex qualitative diagnostics and increase the reliability and efficiency of diagnosis. A methodology for analyzing biomedical images was formed based on the fuzzy set apparatus, which allowed a fuller assessment of the level of disease for glaucoma patients. Aspects of the practical implementation of the optical–electronic system for biomedical information processing were considered. An algorithm and an optical–electronic system for biomedical image analysis are proposed, and they can be used to increase the informativeness and reliability in the diagnosis of eye pathologies and glaucoma in particular.

Using the set of informative features of a binding object to construct a decision function by the system of technical vision when localizing mobile robots

The object of this study is the process of constructing a decision function by the optical-electronic system of technical vision under the conditions of the influence of obstacles on the current image, which is formed in the process of localization of a mobile robot. The paper reports the results of solving the problem of constructing a decision function when reducing the signal-to-noise ratio of the current image by using a set of informative features for the selection of the binding object, namely, brightness, contrast, and its area. The selection of the binding object is proposed to be carried out by choosing the appropriate values of the quantization thresholds of the current image for the selected informative features, taking into account the signal-to-noise ratio, which provides the necessary probability of object selection. The dependence of the object selection probability on the selected values of the quantization thresholds was established. The use of the results could enable the construction of a unimodal decision function when localizing mobile robots on imaging surfaces with weakly pronounced brightness and contrast characteristics of objects, as well as with their small geometric dimensions. By modeling, the probability of forming a decision function was estimated depending on the degree of noise of the current images. It is shown that the application of the proposed approach allows selection of objects with a probability ranging from 0.78 to 0.99 for the values of the signal-to-noise ratio of images formed by the technical vision system under real conditions. The method to construct a decision function under the influence of interference could be implemented in information processing algorithms used in optical-electronic technical vision systems for the navigation of unmanned aerial vehicles

METHODOLOGY FOR ASSESSING THE EFFECTIVENESS OF THE FUNCTIONING OF OPTICAL-ELECTRONIC SYSTEMS WHEN MONITORING REMOTE OBJECTS

The work proposes an approach to improving the scientific and methodological apparatus for processing information about observed distant objects. The potential possibility of increasing the accuracy of measuring the coordinates of remote objects and obtaining spectrophotometric information through a refined mathematical model of the process of functioning of optical-electronic systems, based on the possibility of restoring the original signal from the observed object by solving the Fredholm integral equation of the 1st kind, is shown. Based on a mathematical model that takes into account the structure of the optical circuit, the influence of noise and external observation conditions, the methodology for assessing the effectiveness of optical-electronic systems when observing remote objects has been improved.

Mathematical Model for Constructing a Map of the Location of Areas that Make Up the Background Environment for Optical-Electronic Systems

A developed mathematical model is presented for constructing a map of the location of areas that make up the background environment for optical-electronic systems. A feature of the proposed model is that when determining which class a particular pixel belongs to, the class values of neighboring pixels, as well as the spatial position of the pixel, are simultaneously taken into account. Quantitative assessments of the adequacy of this model and existing mathematical image models capable of constructing maps of the location of areas are given. The proposed model was compared with the Markov model, block Markov model, Gibbs model, block Gibbs model and doubly stochastic model with level quantization. Adequacy assessment was carried out using an artificial neural network developed by the authors, which evaluates the similarity of two images using a normalized similarity index ranging from 0.0 to 1.0, and its k-fold cross-validation. The comparison results showed that the developed model, according to the calculated indicator, is at least three times better than the known ones.

Integration of jackfruit seed-derived carbon dots and electronic nose for a sensitive detection of formaldehyde vapor

The preparation of carbon dots from jackfruit seeds through a pyrolysis method at 280℃ and their use for the detection of formaldehyde were reported. The as-prepared carbon dots showed a high fluorescence efficiency with a quantum yield of 12.7% and excellent photostability and dispersibility in aqueous solution with a zeta potential of ‒62.5 mV. The integration of carbon dot thin film and a home-made optical electronic nose system possessed sensitivity towards formaldehyde vapor with a detection limit of 24.7%v/v across a linear range of 25%v/v to 100%v/v. Furthermore, the sensor showed the highest sensitivity towards formaldehyde against other volatile organic compounds through a strong interaction between the carbonyl groups and the carbon dots. Additionally, principal component analysis (PCA) was conducted to achieve quantitative measurements of formaldehyde content in different formaldehyde volume ratios with substantial variance. Due to the significance of methanol as a typical chemical precursor for the industrial manufacturing of formaldehyde, the quantitative analytical method is essential to determining formaldehyde or methanol concentration. The sensing ability of carbon dot film-integrated electronic nose towards formaldehyde in formaldehyde/methanol mixtures was measured to be 10.74%v/v in a linear range of 25%v/v to 100%v/v. The PCA showed orderly linear combinations of the data set, which can be potentially utilized to analyze formaldehyde and methanol content in industrial processes. The results indicate the significant potential of carbon dots and optical electronic nose system as an effective formaldehyde sensing platform. Potential applications include the quantification of formaldehyde from methanol conversion and determination of methanol contaminant in formaldehyde.

METHODOLOGY FOR EVALUATING THE EFFECTIVENESS OF OPTOELECTRONIC SYSTEMS WHEN OBSERVING REMOTE SMALL-SIZED INCONSPICUOUS OBJECTS

Aspects of the functioning of optical-electronic systems (OES) in the observation of remote, inconspicuous objects are considered. A technique has been developed for determining the effectiveness of the OES with an assessment of the results of observation of remote objects. A feature of the technique is the ability to identify and take into account the most significant factors that affect the result of the functioning of the OES: the characteristics of the brightness structure of the observed objects, the state of the radiation propagation path to the observation point, the circuitry of the optical system, and the parameters of the modes of the photodetector with a given topology. It is shown that the technique makes it possible to implement the optimal choice of algorithms for determining the coordinates and geometric features of inconspicuous objects. The practical application of the methodology makes it possible to more reliably assess the accuracy of coordinate information about remote objects, as well as to determine the degree of influence of various external and internal factors on the performance indicators of the OES, on the one hand, on the other hand, to form the main parameters of the system for given conditions of observation and solving target problems.

Multipurpose fluorescent carbon dots from papaya seed waste as sensing materials for Cu2+ detection and diethyl ether vapor sensor via electronic nose system

Herein, carbon dots (CDs) as biocompatible, fluorescent carbon-based nanomaterials were synthesized from papaya seed waste as renewable carbon sources for the first time via a facile acid pyrolysis method. The papaya seed-derived CDs showed blue fluorescence emission under UV light (365 nm) with a quantum yield of 2.74%, and contained oxygen-, and nitrogen- containing functional groups. Due to their surface functionality, the CDs have a great potential for using as fluorescence sensing probe in metal ion sensing application. The CD solution exhibited the most selective detection to Cu2+ as presented the highest fluorescence quenching with the limit of detection (LOD) of 5.16 μM. The CD-paper-based fluorescent sensor was also developed for practical application, and the RGB value was used to compare the sensitivity of CDs toward metal ions. The CD sensing film was also prepared for diethyl ether vapor sensing via optical electronic nose system. The principal component analysis (PCA) score plots revealed the total variance of 99.3%, indicating that the CDs can be used to discriminate different concentrations of diethyl ether/ethanol vapor mixtures. This work demonstrated that the papaya seed-derived CDs have a great attention to be alternative materials for developing sensing materials in both solution and film forms.

Method for Aligning Instrument and Related Coordinate Systems on Aircraft

A method is proposed for coordinating the instrumental coordinate systems of different posts of the optical-electronic system of aircraft with each other and with the inertial navigation system. The method does not require preflight preparation and is based on processing video information streams generated by thermal imaging and television channels of the optoelectronic system and using information from inertial navigational and radar systems when performing special maneuvers. Theoretical analysis of the accuracy and modeling showed the potential benefits of the proposed method.

Пассивные стекла в системах наблюдения

The analysis of the possibilities of determining the spectrum of electromagnetic radiation from celestial objects using the optical-electronic system of the telescope using CCD receivers is carried out. It is shown that with the introduction of new CCD-type receivers into photometry, the efficiency of observing celestial objects has significantly increased, but despite the positive result, it is necessary to eliminate problems when registering objects with weak radiation during measurements. The purpose of the article is based on the results of experimental studies of thermomechanical and optical properties of multicomponent glasses to provide a justification for the introduction of new materials with a wider transmission range of radiation in various spectra as elements of optical systems of telescopes. In the course of research of new optical materials using the spectroscopy method, optimal compositions of multicomponent glasses were found, allowing to perceive electromagnetic radiation from celestial bodies in various ranges of the infrared spectrum. In conclusion, the results of the study are presented, showing that the introduction of indium and lead fluorides into the composition of multicomponent glass significantly increases the transmission range, which will increase the efficiency of the optical system when using these materials for its elements.

INVESTIGATION OF AN OPTOELECTRONIC SYSTEM FOR DETECTING SMALL-SIZED AND INCONSPICUOUS OBJECTSUNDER THE INFLUENCE OF GEOMETRIC NOISE OF A MATRIX PHOTODETECTOR

The basis for reducing the accuracy of obtaining coordinate and non-coordinate information in an optical-electronic system with a matrix photo detector is geometric noise caused by uneven sensitivity and topology of the photodiode matrix. The presented mathematical model of a matrix photodetector based on the geometric array of photodiodes takes into account the main geometric parameters of the topology of the photodiode matrix. The questions of the accuracy of determining coordinates for small-sized and hardly noticeable light objects comparable to the size of a raster by the method of continuous wavelet transforms of signals from a photodiode array are considered. The possibility of geometric noise filtering by the method of continuous wavelet transform is shown by excluding from the scalogram the range of wavelet transform scales corresponding to the period of the geometric raster. It is shown that the algorithms of continuous wavelet transforms provide an increase in the accuracy of extracting the information component of small-sized and inconspicuous objects observed by an optoelectronic system with a matrix photodetector. A software prototype in the NI LabVIEW application development environment is presented. A technique has been developed for carrying out computational experiments to estimate the accuracy of determining the coordinate depending on the position of a small-sized light object relative to the topological raster of a matrix photodetector, as well as to estimate the detection sensitivity at a given noise level of photodiodes. An assessment of the accuracy of obtaining coordinate and non-coordinate information by a matrix photodetector under the influence of geometric noise has been carried out. It has been established that the filtering of geometric noise provides an increase in the detectivity of the optoelectronic system for detecting small-sized and inconspicuous light objects by more than one and a half times.

EVALUATION OF THE EFFICIENCY OF ADAPTIVE MONITORING GROUND SURFACES WHEN FLYING ABOVE CUMULUS CLOUDS ONBOARD OPTICAL-ELECTRONIC SYSTEMS

The spatial structure of the cloud cover located between the aircraft and the Earth’s surface strongly affects the result of monitoring of the Earth’s surface by Multi-Spectral Optical Electronic System of aircraft. The method of adaptive scanning of Earth’s surface was proposed in previous work to solve the above problem. This article is a continuation of previous work. There is the calculation of the efficiency of the proposed adaptive monitoring in this article. The calculation is carried out for the cases, when the rate of change of the position of the narrow field of view has no mechanical restrictions. The ratio of the area of unseen underlying surface to the whole area of underlying surface is taken as the loss function for calculation of the efficiency of monitoring. This loss function allows us to calculate the efficiency of monitoring as the calculation of restrictions of the duration of optical contact with the object. The calculation is carried out with a known mathematical expectation of the distance between the centers of adjacent (neighboring) clouds. Estimates of the corresponding mathematical expectations are taken for a given lateral displacement of the sought object, the flight altitude of the aircraft and the statistical characteristics of spatial structure of the cloud. This data is taken from meteorological reference books. The analytical expressions and the calculations, which are given in this article, can be used as a basis for development of the algorithms of the adaptive control of the orientation of a narrow field of view for Multi-Spectral Optical Electronic System.

Features of measurements the IR radiation power of a laser diode used in active optoelectronic systems for studying flows

In active optical-electronic systems for stream research that regulate thermal-physical parameters of diagnosed stream volume, the controlled source of the heat flow can be acquired by radiation of high-power IR laser diodes into the void. In the current work the peculiarities of measurement of this radiation are considered, specified by its strong divergence. It is shown that the measurements can involve laser wattmeters IMO-4M with planar thermoelectric primary measuring transformers of the laser radiation with a flat receiving site provided.

Investigation of the accuracy of measuring the parameters of remote objects observed by the optical-electronic system with a light field recorder

The paper considers the construction of optoelectronic systems for monitoring near-Earth space, the choice of algorithms for identifying and obtaining the most reliable coordinate and non-coordinate information about space objects of natural and man-made origin. Experimental mock-up studies using the developed installation were performed. The plant allows the calibration of the optoelectronic system and the study of algorithms for obtaining coordinate and detailed data about the observed objects. The authors apply the method of image registration by a telescopic system in the astrograph with a digital camera mode and a digital camera with a microlens array mode. The work uses the methods for analyzing two-dimensional images by algorithms for measuring binary clusters in an image structure, investigating the brightness structure of an image with a circular boundary in a given area, determining the centers and radii of the circles inscribed in clusters, calculating and estimating the maxima for the curves of the coefficients of continuous wavelet transformation in the image profile lines with real wavelets. The composition and structure of a complex of algorithms and a methodology for their application have been developed. The methodology makes it possible to increase the accuracy and reliability of information obtained about the observed objects in a wide range of changes in the characteristics of the background target environment. The results substantiate the possibility of increasing the accuracy and reliability of coordinate information about the observed objects by analyzing the curves of the coefficients of continuous wavelet transform or analyzing the brightness gradient, provided that the algorithm for analyzing clusters of binarized images is used. The algorithm makes it possible to determine the areas of localization of objects of interest in the observed space. The developed methodology can be applied to assess the accuracy and reliability of the results of determining the coordinates and detailed features of objects. At the same time, it is possible to scale the algorithms to the means of observation and the tasks being solved, which makes it possible to use them in automated monitoring systems for near-earth space and increases the efficiency of detection and identification of objects.

Phased array radar system design based on single-send and multiple-receive for LSS-UAV target

In order to improve the precision of radar target positioning, the phased array frequency modulated continuous wave (FMCW) radar system based on single-send and multiple-receive is proposed for low altitude, slow speed, small Unmanned Aerial Vehicle (LSS-UAV) target. The much lower-cost passive electronically scanned array (PESA) radar technology has been employed for the azimuth electronically scanning. In addition, wide beam scanning beam of elevation direction is used to further expand the range of space coverage. Phase-comparison method is adopted to high-precision angle measurement of elevation direction in interferometer angle measurement system with dual distributed receivers. As a result, the novel radar system possesses the abilities of Doppler velocity measurement and linear FMCW distance measurement, as well as the high precision angle measurement at the same time. It can provide long distance, wide range, all-weather/time detection accurate target location information for optical system and electronic interception system to detect LSS-UAV targets for some more cost-sensitive applications in the homeland security market.

Optical-Electronic System for Detecting Light Reflecting Objects Based on Probing by Pulsed Laser Radiation

Optical-Electronic System for Detecting Light Reflecting Objects Based on Probing by Pulsed Laser Radiation

METHOD FOR DETERMINING THE MISALIGNMENT OF OPTICAL-ELECTRONIC AND INERTIAL ORIENTATIONS HELICOPTER SYSTEMS

A unique method for determining the misalignment of the orientation of the instrumental coordinate systems of different posts of the optical-electronic system of a helicopter with each other and with an inertial navigation system is proposed. The method does not require preflight preparation, and is based on processing video information streams generated by thermal imaging and television channels of the optical-electronic system, and using information from an inertial navigation system. The method involves the helicopter performing a special maneuver, which is a rotation of the helicopter at a low altitude. This maneuver can be automated. When the helicopter rotates, trajectories of characteristic points of the underlying surface and airfield infrastructure are formed on the images. In general, the trajectories of these points are hyperbolas, which are approximated by straight lines. The parameters of these straight lines are determined using the least squares method. The angle of inclination of straight lines in the screen coordinate system determines the position of the angular velocity vector in the instrument coordinate systems. Since all the posts of the optical-electronic system measure the same vector, it is possible to determine their mismatch in roll between themselves and with the inertial navigation system. Preliminary modeling showed high potentialities of the proposed method. The method can be considered as an integral part of a more general method for coordinating coordinate systems in roll, pitch and course based on processing video streams of optical-electronic systems. When the method is used in real conditions, the errors in estimating the angular misalignment of the optical-electronic and inertial systems of a helicopter can be in units of arc minutes.

An analysis of additional errors of the optical-electronic system for monitoring the railway track position

Subject of research. The paper considers an additional error in the railway track position control by stereoscopic methods and examines how the components of the error influence on the measurement results of linear displacements of the track in the profile and plan. Method. The authors propose to use active reference marks located on the supports of the contact network and describe a method for assessing additional errors of the track position control made by a stereoscopic optical-electronic system. On the basis of computer modeling, we investigate the degree of influence of the components of the system error on the total value of the additional error. The conclusions are formulated through analysis of the diagrams obtained via a computer model and the results of an experimental study of the system’s technological samples. Main results. The work reports on the relationship between the linear displacements of the track in the profile and plan with the coordinates of the reference marks as well as the parameters of the system elements with the informative parameters of the signal. A mathematical description of the components of additional errors of the stereoscopic system with changes in the medium temperature, vibration amplitude, vertical gradient of the air path temperature, and movement speed is proposed. It is shown that the components of the error caused by vibrations, inertia of the system, and thermal deformation of the base unit produce the greatest effect on the total additional error in decreasing order. Theoretical, experimental and field testing have shown that the assessment of the random component of the displacement control error when measuring the track position does not exceed 0.8 mm in the longitudinal profile, and 1.8 mm in the plan. Practical relevance. The authors developed a method for studying additional errors in determining the displacement of the track in the profile and in the plan by means of a stereoscopic control system. The prepared recommendations can reduce the most strongly influencing components of the additional error. A stand and software for static and dynamic testing of physical models have been created. The proposed solutions are aimed at achieving full automation of control of the actual position of the railway track when servicing continuous straightening technologies with high-performance track machines using stereoscopic optical-electronic systems. The results can be applied by developers of high-precision optical-electronic systems for ensuring the safety of railway traffic.

Methodology for estimating the efficiency of optical-electronic systems using an analytical model. Functions of threshold contrast and modulation transfer

Efficiency assessment is an integral part of the stages of development, testing and operation of optoelectronic systems. The lack of a unified methodology for assessing the effectiveness of optoelectronic systems leads to the fact that different assessment methods are used to compare different systems, as a result of which the results obtained are contradictory and do not provide objective data for making appropriate decisions at various stages of the life cycle of optoelectronic systems. One of the ways to solve this problem is the development of an analytical model, which can be the basis for the construction of a unified set of intellectual support for the design and maintenance of optical-electronic systems at all stages of the life cycle. The aim of the study is to form an analytical model for evaluating the effectiveness of optoelectronic systems, in terms of the functions of threshold contrast and modulation transfer. As a result, the analysis of models for evaluating the efficiency of the optoelectronic systems NVL 1975, FLIR92, NVTerm, NVTermIP and NV-IPM was carried out, and the main differences between these models were considered. The functions of the threshold system contrast and the threshold contrast of the human visual system are considered. The effect on the form of the threshold contrast function of the modulation transfer function (frequency-contrast characteristic) of the system and the external environment, as well as space-time noise, is shown. Then, a description is given of the components of the modulation transfer function of the system and the environment: the modulation transfer function of the turbulence of the atmosphere, the transfer function of the motion modulation of the optoelectronic system, the modulation transfer function of the optical system, the detector modulation transfer function; image processing modulation transmission functions. Monitor modulation transfer functions. The main parameters of the modulation transfer function, which are used to estimate the resolution of the optoelectronic system, are considered. Examples of evaluating the resolving power of various optoelectronic systems are given and the effect of smearing caused by the movement of the carrier of the optoelectronic system on the image quality for different values of exposure time is shown. The practical significance lies in the fact that the research results were applied in the development of tactical and technical requirements for optoelectronic systems, in the development of optoelectronic systems at the stages of preliminary and technical design, showed the consistency of the calculation results with the results of using existing systems.

Technical aspects of creating radiotechnical systems of information and command interface to ensure the functioning of complexes with unmanned aerial vehicles

One of the key components of the complexes with unmanned aerial vehicles (CUAV), which significantly affects the safety and reliability of operation, is the radio link for transmitting command-telemetric and target information of direct radio visibility (radio engineering system of information and command interface) between unmanned aerial vehicles (UAV) and the ground control and information processing point (GCSP). Heavy-class unmanned aerial vehicles can have several target loads simultaneously – a multispectral optical-electronic system, a digital aerial photo system, a radar system, a radio monitoring system, etc. Due to the fact that the flow of information with the payloads to the input of the radio link during peak time moments can be quite large, severe requirements are imposed as to the equipment of primary processing of the target information aboard the UAV and it’s compression in the recording information, and the bandwidth of the radio link in terms of transmission target information on GCSP for subsequent analysis and processing by the operator of the complex. Technical articles are the justification of modern approaches to the development of radio systems of information and team mates in the functioning of complexes with unmanned aerial vehicles, modeling and analysis of directional properties of the antenna system on the basis of the active phased array antenna (APAA) to ensure that decisions adopted targets CUAV, calculation and modeling of the use of various signal-code structures in the information and command-telemetry channels of the CUAV in order to assess the achievable data transfer rates and the energy budget of radio lines. The main tasks of the article are consideration of the nomenclature of possible target tasks of complexes with UAV, proposals for the technical implementation of radio systems of information and team mates, analysis of the advantages of using APAA as part of an unmanned aerial vehicle and a ground control and information processing point in order to improve the efficiency of UAV complexes in the end, modeling of directional diagrams in the azimuth and angular planes for receiving and transmitting modules and receiving and transmitting panels from the APAA, calculation of the energy budget of information and command radio lines, plotting the dependences of the error probability on the signal-to-noise ratio for various combinations of signal modulations and noise-tolerant encoding for various models of communication channels (additive white Gaussian noise – AWGN and binary-symmetric channel – BSC). The main results of the article include specific practical suggestions and recommendations on hardware and software approaches to the creation of antenna systems based on APAA as part of the CUAV, the effect of using modern approaches (reliability, reduced labor intensity and cost, improved performance characteristics), calculated signal-to-noise ratios for various methods of modulation and encoding, obtained as a result of calculations and mathematical modeling, as well as suggestions and recommendations for the rational use of specific types of signals and codes in the command-telemetry and information channels.

Optical-electronic monitoring system of biomedical indicators

The work is devoted to the development of medical systems for monitoring biomedical indicators. The problem of developing a universal hardware software-controlled control system for the diagnosis of biological objects is solved. The main requirements for such a system are a wide range of functionality for combining different methods of measurement transformation and compliance with modern trends in the development of microelectronic sensors. Given the requirements for modern microcircuitry, in particular for sensing devices of the Internet of Things, the signal path of the sensors is implemented on the basis of PSoC family 5LP Family Cypress. Approbation of the developed system is carried out in the course of research of the character of optical radiation in the course of measurement of biomedical indicators.