Computer Optics

152-157

Authors: Masalsky N.V.

A promising approach to simulating characteristics of silicon nanophotonic modulators fabricated using a standard Silicon On Insulator (SOI) fabrication process is discussed. Optical characteristics of the waveguide structure are changed by means of the free-carrier dispersion effect. On the basis of numerical calculations, the device topological parameters are optimized for achievement of superior modulation characteristics.

163-171

Authors: Kotlyar V.V., Kozlov D.A., Kovalev A.A.

When a dielectric circular cylinder of specific radius is illuminated by a plane wave, a whispering gallery mode (WGM) is generated in the cylinder. This resonant radius of the cylinder can be derived numerically on the assumption of the maximal value of the coefficient in a Bessel series expansion of the E-field amplitude of the TE-wave. Equations composed of cylinder functions are obtained, allowing the cylinder’s resonant radius to be calculated approximately. For instance, based on the equations, one can accurately determine eight initial significant digits of the cylinder resonant radius for a WGM with mode number N= 26 to be generated. In a cylinder with refractive index n = 1.59 and resonant radius R= 3.469239λ (λ is wavelength), a WGM with mode number N= 30 is excited. Such a WGM cylinder can generate an external focal spot of size 0.15λ, with its maximal intensity being 1500 times higher than that of incident light.

181-186

Authors: Skidanov R.V., Ganchevskaya S.V.

We proposed an algorithm for calculating a DOE forming vortex beams with a preset distribution of minima and maxima. We discussed several versions of this algorithm. We presented the calculation of some configurations of traps to capture transparent and non-transparent micro-objects.

197-203

Authors: Ivakhnik V.V., Savelyev M.V.

Spatial selectivity of the degenerate four-wave radiation converter in a transparent twocomponent medium based on electrostriction and Dufour effect has been analyzed as a function of the reflection coefficient. The dependences of the reflection coefficient and the band half-width of spatial frequencies not reflected by such a converter on the intensity of pump waves have been shown to correlate.

211-217

Authors: Karpeev S.V., Khonina S.N., Kharitonov S.I.

A dispersive element in the form of the diffraction grating on a convex mirror surface is investigated. The groove profile of the grating is measured and the intensity distribution between the diffraction orders is calculated as a function of wavelength for the visible spectrum. Optomechanical elements for the required alignments of the spectrometer elements are designed and fabricated. Adjustment of a prototype optical scheme is implemented and point images for three monochromatic incident wavelengths are obtained. The energy distribution between the diffraction orders and the intensity maxima positions are in agreement with the simulation results.

224-233

Authors: Anshakov G.P., Zhuravel Y.N., Raschupkin A.V.

Remote sensing data is a modern tool for efficient reception of data relating to potential natural disasters. This article looks into the feasibility of using the Resurs-P-1 satellite hyperspectral images to evaluate the ice conditions on the Volga river and lakes of the Samara region, as well as monitoring river and reservoir ecological conditions during spring.

241-248

Authors: Chernov V.M.

In this paper a new “error-free” algorithm for discrete circular convolution calculation is proposed. The algorithm is based on a new type of discrete orthogonal transforms for which there exist efficient multiplication-free implementations. The structure of these transforms is associated with the representation of data in the redundant number system associated with Lucas numbers.

255-264

Authors: Zherdev D.A., Kazanskiy N.L., Fursov V.A.

We suggest an object recognition method based on synthetic aperture radar images. The socalled conjugation index between the vector under recognition and a subspace composed of vectors of a training set has been used as a distance function. The processes of clustering have been constructed using support subspaces. Different processes of the training set resampling through the exclusion of vague vectors from the set using the conjugation index have been discussed. The dependence of the recognition quality on the support subspace dimension has been analyzed. The results of experiments demonstrate that the proposed method provides a higher recognition quality than that offered by the support vector method (SVM).

275-280

Authors: Bolotova Yu.A., Spitsyn V.G., Rudometkina M.N.

This paper proposes a license plate recognition algorithm that consists of three major steps: image preprocessing, segmentation, and recognition, which works efficiently with day- and nighttime images, as well as with the license plate being tilted. Pre-filtration allows the sequential binarization to be conducted efficiently. Typically, the license plate segmentation is realized by a histogram method with the preliminary plate de-rotation to the horizontal osition, thus deteriorating the original image quality. In this paper the segmentation is implemented by a connected components method, enabling the rotation and a consequent loss of quality to be avoided. The hierarchical temporal network shows good results in rotated symbols recognition. The proposed method can be used in a similar way for segmentation and recognition of various text data. The proposed algorithms can also be used for distorted text segmentation and recognition.

287-293

Authors: Gaidel A.V.

As part of the general problem of automatic information feature construction, we considered a particular applied problem of the calculation direction adjustment for the directed texture features intended to diagnose various diseases from digital biomedical images. As feature space quality criteria, we considered the classification accuracy, Bhattacharyya distance and the discriminant analysis criteria. We used random search, a genetic algorithm and simulated annealing as the optimization algorithms. The proposed approach enables a two-fold reduction in the error probability estimation when diagnosing bone tissue X-ray images (from 0.20 to 0.10), also enabling a 45-percent error reduction when diagnosing computed tomography (CT) lung images (from 0.11 to 0.06) in comparison with conventional procedures of selecting from a large number of heterogeneous features.