Оценка качества и идентификация отпечатков пальцев путем анализа структурных свойств изображения

The paper addresses the problem of assessing the quality of fingerprint images using spatial analysis methods. The author proposes using the previously developed mathematical model to describe the set of magnitudes of the image gradient. The model is based on the two-parameter Weibull distribution. The author proposes two approaches to assess the quality of fingerprints. The first approach is implemented by the so-called “Full reference method”, which compares the Weibull distribution parameters’ values of statistical estimates. The results of identifying sweat pores using this method are presented. The second approach is called the “No-Reference method” and is used to assess fingerprints’ quality when analyzing and identifying the information content of their individual sections. It is proposed to use an image blur map as a quality characteristic and a statistical estimate of the Weibull distribution shape parameter as a measure of the blur. The shape parameter is estimated at each image point by the combination of magnitudes of the image gradient in the vicinity of the point; in this, the previously developed blur mapping technique is applied. The specific examples illustrate effectiveness of the proposed approaches.Рассмотрена задача оценки качества изображения отпечатков пальцев с применением пространственных методов анализа. Предложено использовать математическую модель, разработанную ранее для описания совокупности магнитуд градиента изображения. Модель основана на двухпараметрическом распределении Вейбулла. Для оценки качества отпечатков пальцев предложены два подхода. Первый реализуется с помощью так называемого метода сравнения с эталоном (Full Reference), когда сравниваются значения статистических оценок параметров распределения Вейбулла. Приведены результаты решения задачи идентификации потовых пор этим методом. Второй подход называется «безэталонным» (No-Reference) и применяется для оценки качества отпечатков при анализе и выделении информативности их отдельных участков. В качестве характеристики качества предлагается использовать карту размытости изображения, а в качестве меры размытости – статистическую оценку параметра формы распределения Вейбулла. Параметр формы оценивается в каждой точке изображения по совокупности магнитуд градиента изображения в окрестности точки, при этом применяется разработанная ранее методика построения карты размытости. Эффективность предложенных подходов иллюстрируется конкретными примерами

b→sγb \to s \gamma decays in the Left-Right Symmetric Model

We consider $b \to s \gamma$ decays in the Left-Right Symmetric Model. Values of observables sensitive to chiral structure such as the $\Lambda$ polarization in the $\Lambda_b \to \Lambda \gamma$ decays and the mixing-induced CP asymmetries in the $B_{d,s} \to M^0 \gamma$ decays can deviate in the LRSM significantly from the SM values. The combined analysis of $P_\Lambda$ and $A_{CP}$ as well as ${\cal BR}(b \to s \gamma)$ can be used to determine the model parameters.Comment: 16 pages with 7 figures, Version to be published in PR

Direct CP-asymmetry in Inclusive Rare B-decays in 2HDM

The direct CP-asymmetry in the inclusive $B \to X_d \gamma$ and $B \to X_d e^+ e^ -$ decays is investigated in the two-Higgs doublet extension of the Standard Model (2HDM). The investigation is performed in the lowest non-vanishing order of the perturbation theory using the existing restrictions on the 2HDM parameters space. It is shown that the direct CP-asymmetry in the $B \to X_d \gamma$ decay can deviate significantly from the Standard Model predictions. In the presence of only one source of CP-violation (the CKM matrix weak phase) $a_{CP}(B \to X_d \gamma)$ can have the sign opposite to that in the SM. The new source of CP-violation can make $|a_{CP}(B \to X_d \gamma)|$ arbitrary small (unlike the SM case) and hence unmeasurable. Quantitatively, the obtained results suffer from the uncertainty of the choice of renormalization scale. As for the $B \to X_d e^+ e^ -$ rate asymmetry, its renormalization scale dependence in the lowest non-vanishing order does not allow to conclude if this quantity is efficient for testing New Physics beyond the Standard Model.Comment: 16 pages including 2 figure

Manifestation of photonic band structure in small clusters of spherical particles

We study the formation of the photonic band structure in small clusters of dielectric spheres. The first signs of the band structure, an attribute of an infinite crystal, can appear for clusters of 5 particles. Density of resonant states of a cluster of 32 spheres may exhibit a well defined structure similar to the density of electromagnetic states of the infinite photonic crystal. The resonant mode structure of finite-size aggregates is shown to be insensitive to random displacements of particles off the perfect lattice positions as large as half-radius of the particle. The results were obtained by an efficient numerical method, which relates the density of resonant states to the the scattering coefficients of the electromagnetic scattering problem. Generalized multisphere Mie (GMM) solution was used to obtain scattering matrix elements. These results are important to miniature photonic crystal design as well as understanding of light localization in dense random media.Comment: 4 pages, 2 figure

More Model-Independent Analysis of b->s Processes

We study model-independently the implications of non-standard scalar and pseudoscalar interactions for the decays b ->s gamma, b -> s g, b -> s l^+l^- (l=e,mu) and B_s -> mu^+ mu^-. We find sizeable renormalization effects from scalar and pseudoscalar four-quark operators in the radiative decays and at O(alpha_s) in hadronic b decays. Constraints on the Wilson coefficients of an extended operator basis are worked out. Further, the ratios R_H = BR(B -> H mu^+ mu^-)/BR(B -> H e^+ e^-), for H=K^(*), X_s, and their correlations with B_s -> mu^+ mu^- decay are investigated. We show that the Standard Model prediction for these ratios defined with the same cut on the dilepton mass for electron and muon modes, R_H= 1 + O(m^2_mu/m^2_b), has a much smaller theoretical uncertainty (<1%) than the one for the individual branching fractions. The present experimental limit R_K < 1.2 puts constraints on scalar and pseudoscalar couplings, which are similar to the ones from current data on BR(B_s -> mu^+ mu^-). We find that new physics corrections to R_{K*} and R_{X_s} can reach 13% and 10%, respectively.Comment: 28 pages, 6 figures; Table 1 updated, two refs added (to appear in PRD

b→sγb \to s \gamma Decay in SU(2)L×SU(2)R×U(1)SU(2)_L \times SU(2)_R \times U(1) Extensions of the Standard Model

The rare radiative decay $b \to s \gamma$ is studied in $SU(2)_L \times SU(2)_R \times U(1)$ extensions of the Standard Model. Matching conditions for coefficients of operators appearing in the low energy effective Hamiltonian for this process are derived, and QCD corrections to these coefficients are analyzed. The $b \to s \gamma$ decay rate is then calculated and compared with the corresponding Standard Model result. We find that observable deviations from Standard Model predictions can occur in $SU(2)_L \times SU(2)_R \times U(1)$ theories for a reasonable range of parameter values.Comment: 17 pages with 5 figures not included but available upon request, CALT-68-1893, TUM-T31-52/9

Unconstrained SU(2) Yang-Mills Quantum Mechanics with Theta Angle

The unconstrained classical system equivalent to spatially homogeneous SU(2) Yang-Mills theory with theta angle is obtained and canonically quantized. The Schr\"odinger eigenvalue problem is solved approximately for the low lying states using variational calculation. The properties of the groundstate are discussed, in particular its electric and magnetic properties, and the value of the "gluon condensate" is calculated. Furthermore it is shown that the energy spectrum of SU(2) Yang-Mills quantum mechanics is independent of the theta angle. Explicit evaluation of the Witten formula for the topological susceptibility gives strong support for the consistency of the variational results obtained.Comment: 20 pages REVTEX, no figures, one reference added, final version to appear in Phys. Rev.

Direct CP violation in radiative b decays in and beyond the Standard Model

We consider the partial rate asymmetry in the inclusive decay modes b to s gamma and b to d gamma, concentrating on non-standard models with new charged Higgs interactions. We find that the charged Higgs contribution to the asymmetry for b to s gamma is small in such models due to a universal cancellation mechanism. The asymmetry is therefore difficult to distinguish experimentally from the Standard Model (SM) value, which is also small. The cancellation mechanism is found to be rendered inoperative in supersymmetry due to the presence of chargino loops. Unlike b to s gamma, the rate asymmetry for b to d gamma in Higgs models can be quite different from its SM value, generally ranging from -20% to +20%. Specific model calculations are performed for the Three-Higgs Doublet Model and the ``Top'' Two-Higgs Doublet Model to serve as illustrations. We also offer some suggestions that may be helpful to experimentalists in the detection of the inclusive mode b to d gamma.Comment: RevTex, 24 pages, 6 figures, minor changes, version to appear in PR

Hamiltonian reduction of SU(2) Dirac-Yang-Mills mechanics

The SU(2) gauge invariant Dirac-Yang-Mills mechanics of spatially homogeneous isospinor and gauge fields is considered in the framework of the generalized Hamiltonian approach. The unconstrained Hamiltonian system equivalent to the model is obtained using the gaugeless method of Hamiltonian reduction. The latter includes the Abelianization of the first class constraints, putting the second class constraints into the canonical form and performing a canonical transformation to a set of adapted coordinates such that a subset of the new canonical pairs coincides with the second class constraints and part of the new momenta is equal to the Abelian constraints. In the adapted basis the pure gauge degrees of freedom automatically drop out from the consideration after projection of the model onto the constraint shell. Apart from the elimination of these ignorable degrees of freedom a further Hamiltonian reduction is achieved due to the three dimensional group of rigid symmetry possessed by the system.Comment: 25 pages Revtex, no figure

A parametric study of the lensing properties of dodecagonal photonic quasicrystals

We present a study of the lensing properties of two-dimensional (2-D) photonic quasicrystal (PQC) slabs made of dielectric cylinders arranged according to a 12-fold-symmetric square-triangle aperiodic tiling. Our full-wave numerical analysis confirms the results recently emerged in the technical literature and, in particular, the possibility of achieving focusing effects within several frequency regions. However, contrary to the original interpretation, such focusing effects turn out to be critically associated to local symmetry points in the PQC slab, and strongly dependent on its thickness and termination. Nevertheless, our study reveals the presence of some peculiar properties, like the ability to focus the light even for slabs with a reduced lateral width, or beaming effects, which render PQC slabs potentially interesting and worth of deeper investigation. Key words: Photonic quasicrystals; negative refraction; superlensing.Comment: 12 pages, 8 figures, to be pubblished in Photonics and Nanostructures - Fundamentals and Application