Computer Optics

449-452

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

We have obtained explicit expressions for amplitudes of all components of the electric and magnetic vector of a family of vectorial nonparaxial linearly polarized vortex Hankel beams. Thus, closed-form analytical expressions have been derived for the projections of the Umov-Poynting vector and angular momentum vector. Up to now, projections of these vectors have been obtained only for the nonparaxial vectorial Bessel beams and paraxial vectorial Laguerre-Gaussian beams.

459-461

Authors: Volostnikov V.G.

The orbital angular momentum (OAM) for an arbitrary light field as superposition of Hermite-Gaussian modes is considered. An analytical formula for the OAM of such fields is obtained. It is shown that under equal initial conditions, OAM of a linear combination of two Hermite-Gaussian beams derived in this work is equal to that obtained earlier [JOSA A, 31, 274 (2014)]. Relations for more complex combinations of Hermite-Gaussian modes are also derived. It is found that unlike two-mode superposition, in three-mode superposition the OAM can be larger than the maximum index of the superposition for structurally stable light fields.

469-479

Authors: Kharitonov S.I., Volotovskiy S.G., Khonina S.N., Kazanskiy N.L.

In the Introduction section, we offer a historical overview of main experimental and theoretical developments in the field of X-ray crystal analysis. The main part contains a differential approach to solving the problem of diffraction of X-rays by crystals within the scalar theory. Examples of numerical simulation for the basic types of crystal lattices are included.

486-491

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

The spatial and temporal structure of an object wave has been analyzed for a four-wave radiation converter in a transparent two-component medium with regard for the electrostriction and Dufour effect. The bandwidth of high-efficiency conversion has been shown to increase over time. We have shown that for a steady-state spatial spectrum of object waves, the spectrum maximum shifts toward lower spatial frequencies, whereas the bandwidth of high-efficiency conversion is decreasing as the ratio of wavenumbers of pumping waves gets increasingly deviated from unity.

500-507

Authors: Ustinov A.V., Degtyarev S.A., Khonina S.N.

In this paper we consider diffraction of a laser beam by a narrow axicon when the cone angle is much less than a limit (at which total internal reflection occurs). In this case, the correct description of the propagation of light through the axicon calls for the consideration of multiple internal reflections. The diffraction is considered using two models: through a geometric optics approach and via solving the Helmholtz equation by a finite element method. Based on the geometrical model, analytical expressions are found for the angles defining the boundaries of the real and imaginary foci. Simulations conducted using the finite element method have confirmed the theoretical results.

515-520

Authors: Kolyuchkin V.V., Zlokazov E.Yu., Odinokov S.B., Talalaev V.Ye., Tsyganov I.K.

Security holograms have been widely used for document and product authenticity protection. The quality of security holograms and master-matrices significantly depends on the perfection of the diffraction grating. The authors introduce a method for checking the security hologram quality based on indirect measurements of diffraction grating parameters. Theoretical results concerned with the use of this method for microrelief quality control are discussed.

529-535

Authors: Greisukh G.I., Ezhov E.G., Kazin S.V., Stepanov S.A.

Color correction in optical systems with constituent elements synthesized by precision molding is investigated. Advantages associated with the use of the technique are demonstrated.

542-556

Authors: Koltsov P.P., Osipov A.S., Kutsaev A.S., Kravchenko A.A., Kotovich N.V., Zakharov A.V.

The paper contains a brief review of main approaches to the comparative performance evaluation of image analysis algorithms. Some empirical methods used for the comparative evaluation of edge detectors and image segmentation algorithms are considered and quantitative criteria employed in these methods are studied. Problems associated with the use of these criteria are described. Finally, using the edge detector evaluation as an example, we propose an empirical method, called EDEM, which is implemented using our proprietary software system PICASSO.

564-571

Authors: Thanh D.N.H., Dvoenko S.D.

Today, raster images are created by different modern devices, such as digital cameras, X-Ray scanners, and so on. Image noise deteriorates the image quality, thus adversely affecting the result of processing. Biomedical images are an example of digital images. The noise in such raster images is assumed to be a mixture of Gaussian noise and Poisson noise. In this paper, we propose a method to remove these noises based on the total variation of the image brightness function. The proposed model is a combination of two famous denoising models, namely, the ROF model and a modified ROF model.

582-591

Authors: Protsenko V.I., Kazanskiy N.L., Serafimovich P.G.

Analysis of two streaming frameworks: Apache Storm and IBM InfoSphere Streams was performed in solving a multiple object detection task. The analysis focused on two parameters: throughput and 95th percentile of image processing delay. Faces were chosen as the objects to be detected. Profiling was held under CentOS operating systems running on a five node cluster. Face detection was performed using an OpenCV cascade classifier. First architectures and the experiment description were covered. Final suggestions on the applicability of the two systems were made in the concluding section of the article. Apache Storm demonstrated a scalability advantage over IBM InfoSphere Streams in the experiment conducted. It was confirmed that the system based on Apache Storm was able to operate on FullHD video in real-time, achieving throughput of 24 images per second on the hardware used.

600-605

Authors: Kotov A.P., Fursov V.A., Goshin Ye.V.

We propose a fast algorithm for disparity maps construction from stereo images. The reliability and efficiency of image matching in subsequent steps is achieved by using epipolar constraints and an image pyramid. The developed method was implemented on a parallel computing platform CUDA. The results of experimental studies show high performance of the proposed approach, while maintaining the high-quality reconstruction of 3D-scenes.

614-621

Authors: Morozov A.N., Kochikov I.V., Novgorodskaya A.V., Sologub A.A., Fufurin I.L.

In the present paper a problem of substance identification in FTIR (Fourier transform infrared) spectroscopy is considered. The spectral library hitlist search is chosen as the main tactic. In the paper the Pearson correlation coefficient as a similarity criterion between two spectra is suggested. A situation when one of the measured spectra has an additive narrowband white noise component with a Gaussian distribution is considered. In that case the probability density of the correlation coefficient is found. A concept of the probability of correct detection is proposed and a theoretical expression is found. In addition, we consider a boundary correlation coefficient search algorithm, which allows one to find a boundary value providing the required correct detection. Computational experiments have shown the applicability of the method.