This article illustrates a system for stabilizing objects in space based on integral fiber elements. The proposed system showed results commensurate with similar systems with a length of tens of kilometers of SMF-28 optical fiber, while using PANDA type optical fiber is only 200 m. In the work, a model of the system was developed and experimental studies of the response and angular velocity of the gyroscope were carried out.
The paper proposes the use of switches to synthesize immittance logic elements, which makes it possible to ensure the operation of logic elements at various fixed operating frequencies. This in turn allows to increase the operating frequency range of such elements. For the first time, a mathematical model of a multi-frequency immittance logic R-element "NOT" was developed. It allowed to determine the transient characteristics at different operating frequencies. The circuit of the multi-frequency opto-immittance logic R-element "NOT" was developed. The results of the study of its transient characteristics showed the possibility of using the circuit in the design of passive immittance logic elements with an extended operating frequency range.
The problem of extraction of the image objects features by means of using the inverse filters (IF) is considered. The IF are formed by the inversion of the matrix composed of correlation vectors of a set of objects templates examples. The inversion is made with the help of singular value decomposition. Three approaches to regularization and its impact on IF recognition properties are also considered. There was defined the functional that specifies minimal mutual relations between functions of the filters to obtain optimal separation of the features. A training process is used in order to obtain filters with high recognition performance.
KEYWORDS: Digital signal processing, Signal processing, Fiber optics, Telecommunications, Statistical analysis, Signal attenuation, Analog electronics, Analytical research, Phase shift keying, Fourier transforms
The high-performance methods of multi-stage digital processing of linear signals of fiber optic transmission systems in the spectral and time domain with the use of Fourier transform methods are proposed. Based on the proposed methods of signal processing, a digital device for restoring of linear signals in fiber-optic transmission systems is developed. The advantage of the device is high performance, which enables digital processing of linear signals in the spectral region without loss of information.
The paper presents the mathematical apparatus for precise calculation of the three-dimensional point spread function (3D PSF) of optical systems. The method is based on the Huygens-Fresnel principle: a spherical wave on the threedimensional surface of the exit pupil is considered as result of the superposition of elementary secondary point radiation sources. These point sources emit coherent electromagnetic waves with a spherical wave front. They form a certain distribution of generalized complex amplitudes in three-dimensional space near the focus point. This distribution is used to calculate the intensity distribution in the focus area of the optical system, which is the PSF. The advantage of the proposed technique is direct calculation of the 3D PSF with taking into account wave aberrations and without usage of Fresnel or Fraunhofer approximations. In case of small aperture optical systems the proposed technique coincides with classical theory that specifies the link between a pupil function and PSF via Fourier transform. The differences between precise and approximated techniques for 3D PSF calculation are also discussed.
(Cu1-хAgx)7GeS(Se)5I mixed crystals were grown by vertical zone crystallization method, they are shown to crystallize in cubic structure ( F43m space group, Z=4). Refractive indices for (Cu1-xAgx)7GeS(Se)5I mixed crystals were obtained from the spectral ellipsometry measurements. Two anomalies of refractive index in the spectrum region from 300 nm to 1000 nm are observed. One of them corresponds to the band-to-band optical transition while another one to the interband Van Hove-Phillips singularity. The dispersion dependences of refractive indices for (Cu1-хAgx)7GeS(Se)5I mixed crystals in the transparency region is well described by Wemple and DiDomenico model. The influence of the cation Cu→Ag substitution and anion S→Se substitution on the optical parameters of (Cu1-хAgx)7GeS(Se)5I mixed crystals has been investigated.
The work is aimed at the development and experimental testing of the polarization-correlation method for the analysis of the polycrystalline structure of biological layers. introduced a new parameter-complex degree of mutual anisotropy. the statistical (statistical moments of the 1st – 4th orders) structure of the distributions of the values of the cdma module of spatially structured fibrillar networks of histological sections of the myocardium that died due to mechanical asphyxia and heart attack was experimentally studied.
Approaches to the development of the system of audio synthesis and analysis are considered. Described ready to use cloud solutions and their drawbacks that can make engineers choose custom implementation in order to satisfy required use cases that are to be implemented. Considered an option of using optic fiber processors on the server-side application in order to optimize the music recognition flow. Considered various options of build systems that help to configure project build configuration which is especially important while developing cross-platform solutions. Therefore, technologies for developing cross-platform applications and systems are also described. In order to make the system work efficiently, it is important to build all the components in a correct way in order to provide a clean implementation and architecture. Additionally, there are considered approaches of server-side optimization of music recognition and search process by introducing load balancing and parallel matching.
Dual-channel opto-electronic surveillance systems which operate in visible and infrared spectrum ranges are widespread. Their analysis and design needs suitable tools. A simplified physics-mathematical model of a dual-channel optoelectronic surveillance system was developed to determine energy resolution of the system. Noise equivalent brightness difference and noise equivalent temperature difference were used to define the ability of television and thermal imaging systems to detect objects. As an example of applying the model an algorithm of spectral channel selection depending on the conditions of surveillance was developed.
A function-based approach of object rendering based on perturbation functions and 3D textures with the use of graphics processing units is proposed. To generate the terrain and the control in levels of detail, the similar technique as that for color textures is used. A method of real-time rendering of 3D clouds is described. For this aim, it is proposed to form 3D textures by means of pre-processing of the inner cloud pattern and volume-oriented rendering.
This paper investigates the relationship between the integral equation and Kirchhoff approximation in the diffraction theory of coherent radiance. The spectrum of the reflected wave is formed in the far field (Fraunhofer zone) and the solution is to Fourier transform of effective reflectance coefficient of a surface. In the paper, the analytical relationship between the method of solving an integral equation and the Kirchhoff approximation has been proven. It helps to define the structure of the field of diffracted waves in a Fraunhofer zone for coherent scattered light. The analytical equations for calculation of the average value of intensity scattering field and the mirror reflection coefficient of a rough surface have been obtained. Analysis of the components of the scattering coherent light coming from a metal surface has been improved. It helps to specify the data processing algorithms for evaluation of statistical characteristics of rough surfaces.
Among the various characteristics of infrared radiation, the degree of polarization is not often used in radiation analysis. The main reason is that polarization is less informative characteristic compared to others for most practical tasks. Also obtaining polarized radiation in infrared spectrum is relative complex and expensive act. In some cases, such as remote sensing, the improvement of spatial, radiometric and spectral resolution approaches it’s physical limit. It becomes relevant to obtain additional information of a different nature, such as polarization information. Modern infrared radiation polarizers based on diffraction gratings are quite expensive. The article explores the possibility of creating infrared polarizers based on a planeparallel plate, to which radiation falls at an Brewster angle. It is shown that the polarizer operating on transmittance will be more efficient than reflecting radiation polarizer, since it does not deviate the optical axis by a significant angle. Such a polarizer provides a polarization degree of 90% and a transmittance of about 50%.
Algorithm of Ramer–Douglas–Peucker for piecewise approximation was used for image multilevel segmentation. The cumulative histogram was chosen as a function for approximation. The developed algorithm was applied to the satellite map images to divide clouds of different intensity. The map images of clouds with different intensity were clustered to obtaine cloudiness values and classification.
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