Kartheek, Mukku NisanthPrasad, V. N. K. MunagaBhukya, Raju
11页
查看更多>>摘要：Automatic Facial Expression Recognition (FER) is an important research area in computer vision because it has many real-time applications. However, the main issue lies in the design of a feature descriptor that could effectively capture the appearance changes in the facial images. For FER systems, graph based methods have not been much explored for feature extraction. Hence, this paper introduces novel graph based methods named Windmill Graph based Feature Descriptors (WGFD) for feature extraction. Two variants of WGFD's (WGFD(h) and WGFD(v)) have been proposed in this work to effectively encode the relationship among neighboring pixels in a local neighborhood. For expression classification, multi-class Support Vector Machine (SVM) is utilized. The performance of the proposed feature descriptors have been evaluated on six benchmark FER datasets namely JAFFE, KDEF, MUG, CK+, TFEID and FERG with respect to seven expressions classification. The experimental results showed promising results when compared to the recent FER methods.
查看更多>>摘要：In this paper, the propagation of light along a long chain of two dimensional elliptic bars with infinite period is analyzed. Due to the instability of the shape of the ellipse, the propagation characteristics of light will be changed by changing the ratio of the short half axis length to the long half axis length of the ellipse. The Bragg propagation period is observed by the change of phase constant and attenuation constant with the normalized frequency. The waveguide mode, cut-off mode and leakage mode were explained by analyzing the numerical value and field distribution of the cycle results of a single layer elliptic cylinder with different ratios. The results also indicated that, as the ratio increased, the propagation period of Bragg wave became shorter and special multimodal phenomena emerged. In addition, 20 dielectric bar chain structures are used to visually show the electric field propagation.
Hathot, Saba FarhanAbbas, Sabah IbrahimAlOgaili, H. A. T.Salim, A. A....
9页
查看更多>>摘要：Effects of various deposition times (4, 8 and 12 min) on the crystallinity, absorption and electrical characteristics of zinc sulfide thin films (ZSTFs) were evaluated. These films were prepared on glass substrate using chemical spray pyrolysis method. XRD analyses of the ZSTFs revealed hexagonal and cubic phases. The average crystallite size and optical band gap energy of the TFs was varied from 27.81 to 31.54 nm and 2.7-3 eV, respectively. Proposed TFs showed low transmittance in the visible and infrared regions wherein the surface roughness played a significant role. With the increase of deposition time, the refractive indices of the films were increases and the extinction coefficients were reduced. The obtained films disclosed excellent electrical and dielectric traits useful for diverse applications.
查看更多>>摘要：In this research, we analyze the Hasimoto map and some flow equations for spherical frame (s-frame) in S-2 spherical space. Here, we first obtain Hasimoto map, which we call the s- Hasimoto map, for the s-frame in S-2. Then, we get some soliton equations with the help of s-Hasimoto map and vortex filament (Da Rios) equation. Later, by examining the effects of visco-Da Rios equation and visco-Landau Lifshitz equation on s-Hasimoto map, we obtain some flow equations. Finally, we present some of the contributions that all our results will make to magnetic fluxes, fluid dynamics and, especially, optical motion.
查看更多>>摘要：In order to realize the quantitative detection of subsurface cracks, finite element method (FEM) was used to study the interaction of laser-generated Rayleigh wave and subsurface crack with different buried depths and lengths in this paper. The transmitted and reflected Rayleigh waves of subsurface cracks were analyzed in frequency domain, it is found that the center frequency of transmission wave decreases with the increase of crack length when the buried depth of crack remains unchanged, and increases with the increase of crack depth when the crack length remains unchanged. The center frequency of reflected Rayleigh wave is independent of crack length, and has a quadratic function relation with the buried depth of subsurface crack. The relationships, between the ratio of buried depth to incident Rayleigh wavelength and the ratio of reflected Rayleigh wave frequency to incident Rayleigh wave frequency, and the ratio of crack length to incident Rayleigh wavelength and the ratio of transmitted Rayleigh wave frequency to incident Rayleigh wave frequency, were obtained respectively based on the frequency analysis. The relationships were verified by the simulation signals, it is found that the maximum relative error of the buried depth of the subsurface cracks determined by the proposed relationship is 5.939%, and the maximum relative error of the length of the subsurface cracks is 12.149%. The research results show that the proposed method is promising in quantitative characterization of the buried depth and length of subsurface cracks in metallic materials.
查看更多>>摘要：A simple design of photonic crystal fiber (PCF) sensor which utilizes surface plasmon resonance (SPR) for refractive index detection is inspected to achieve high sensitivity. The offered sensor comprises of air holes in square lattice arrangement where two gold nanowires as a plasmonic material are located at the surface. Size-dependent plasmonic features of nanowires facilitates the coupling of SPR and fundamental core modes which leads to enhancement of sensor performance. With the propose of achieving the best result, the geometrical structure including the size of air holes and their arrangement in the PCF and also the size of nanowires are examined, in this work. Sensing performance of the proposed sensor is evaluated by finite element method using Comsol Multiphysics software. In y-polarization mode, the maximum wavelength and amplitude sensitivities of 50000 (nm/RIU) and 672.2 1/RIU have been obtained. The corresponding maximum values of figure of merit and resolution are 250 (1/RIU) and 2 x 10(-6) (RIU), respectively. This sensor includes remarkable prospect in chemical and biomedical detection because of its high sensitivity and low fabrication complexity. For example, the sensor performance is investigated for the cervical cancer cell detection and high sensitivity as 40000 (nm/RIU) is obtained.
查看更多>>摘要：Background subtraction always remains an important and challenging task for different applications. Our previous work established the effectiveness of hybrid model by exploiting the oriented patterns present in a video sequences over other statistical method. To extend this approach further, we have proposed a novel approach herein by eliminating GLCM based features with an improved local Zernike moment and color components of intensity. These features are clubbed with the orientation based features extracted from angle co-occurrence matrices (ACMs) to model the background. Furthermore the Mahalanobis distance measure is replaced by Canberra distance to categorized foreground and background pixels, which significantly reduces the computational complexity of the proposed method due to the absence of covariance matrix measure. Comparative results have shown that our proposed method is effective than other competing method on different set of video sequences.
查看更多>>摘要：High-precision segmentation of retinal vessels is a critical procedure for clinicians to analyze retinal diseases. However, previous U-Net based segmentation methods are lost in the preservation of capillaries and vascular structures of complex bifurcation. To solve these problems, this paper proposes a novel U-Net based network, named Inception-Like U-Net (ILU-Net), including the following key points: First, two different types of inception-like block (Down-sampling Inception Blocks (DIB) in encoder and up-sampling Inception Blocks (UIB) in decoder) replace the two convolution operations in U-Net to learn the characteristics from different sizes of receptive field. Second, a novel skip connection strategy is proposed and can better connect lowlevel features to high-level features for reproducing more micro-scale vascular structures. Third, the segmentation performance is further improved by using the combination of two activation functions (ReLU and ELU). Qualitative and quantitative results of experiments on the public DRIVE dataset demonstrate that the proposed ILU-Net approach is effective and even better than the state-of-the-arts in preserving capillaries and complex bifurcation structures.
Khan, Pedinti ShahabJamalaiah, Bungala ChinnaJayasimha, MulaKaur, Harpreet...
13页
查看更多>>摘要：The SGPEux phosphors of composition Sr3Gd(1-x)(PO4)(3):xEu(3+ ) were synthesized by modified citrate-gel combustion method for white LED sources. The optimum conditions of synthesis were obtained from thermogravimetric and differential scanning calorimetry. The synthesized phosphors were crystallized into BCC structure with JCPDS No. 29-1301. The presence of various bonds due to stretching and bending vibrations of different functional groups were studied through Fourier transform infrared spectroscopy. The morphology was examined using high resolution scanning electron microscopy. The luminescence analysis was carried out through photoluminescence excitation and emission studies. The charge transfer band and f-f transitions of Gd3+ + and Eu3+ ions cause a transfer of energy from Gd3+ to Eu3+ . A suitable excitation wavelength for efficient luminescence was selected as 273 nm by studying the emission properties at different excitations. The quenching in luminescence noticed beyond 2.0 mol% was assigned to non-radiative transitions at higher Eu3+ concentrations. The analysis of colour perception and colour temperature of emitted luminescence was studied using chromaticity coordinates evaluated from the emission spectra. The observed results suggest that the 2.0 mol% of Eu(3+ )doped SGPEu phosphor has more proficiency to design new class of w-LED sources.
查看更多>>摘要：The orbital angular momentum (OAM) carried by vortex beams provides new possibilities for optical communication multiplexing. OAM modes can also carry information due to their helicalphase wave fronts, providing a new mechanism for optical fiber sensing. In this paper, a novel image detection scheme based on OAM intermodal interference in few-mode fibers is proposed. Temperature and strain are measured simultaneously based on components with different azimuthal distributions in the interference pattern. The sensing mechanism and demodulation principle of the proposed sensor are studied, and the linear response range and anti-interference capability are analyzed. Simulation results show that the variations in temperature and strain can be simultaneously demodulated by using a single image obtained at the output of the sensing fiber at a single working wavelength. External optical noise and the internal modal intensity fluctuations, have little effect on the temperature and strain sensitivities of the proposed sensor. The intermodal sensors based on OAM modes have a larger linear response range and better antiinterference capabilities than intermodal sensors based on linear polarization modes.
NSTL
Elsevier