2014
2014
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Record 433 of
Title:NATAS: Neural activity trace aware saliency
Author(s):Zhu, Guokang(1); Wang, Qi(1); Yuan, Yuan(1)Source: IEEE Transactions on Cybernetics Volume: 44 Issue: 7 DOI: 10.1109/TCYB.2013.2279002 Published: July 2014Abstract:Saliency detection has raised much interest in computer vision recently. Many visual saliency models have been developed for individual images, video clips, and image pairs. However, image sequence, one most general occasion in the real world, is not explored yet. A general image sequence is different from video clips whose temporal continuity is maintained and image pairs where common objects exist. It might contain some similar low-level properties while completely distinct contents. Traditional saliency detection methods will fail on these general sequences. Based on this consideration, this paper investigates the shortcomings of the classical saliency detection methods, which significantly limit their advantages: 1) inability to capture the natural connections among sequential images, 2) over-reliance on motion cues, and 3) restriction to image pairs/videos with common objects. In order to address these problems, we propose a framework that performs the following contributions: 1) construct an image data set as benchmark through a rigorously designed behavioral experiment, 2) propose a neural activity trace aware saliency model to capture the general connections among images, and 3) design a novel measure to handle the low-level clues contained among sequential images. Experimental results demonstrate that the proposed saliency model is associated with a tremendous advancement compared with traditional methods when dealing with the general image sequence. ? 2013 IEEE.Accession Number: 20142717881496 -
Record 434 of
Title:Measurement of femtosecond pulse contrast of low-repetition-rate lasers by optical Kerr effect
Author(s):Wu, Dengke(1,2); He, Junfang(1); Zhu, Changjun(3); Wang, Yishan(1); Zhao, Wei(1)Source: Journal of Nonlinear Optical Physics and Materials Volume: 23 Issue: 3 DOI: 10.1142/S0218863514500313 Published: September 25, 2014Abstract:In this paper, pulse contrast was measured for femtosecond lasers with low-repetition-rate (40 Hz) using optical Kerr gate as a sampler. The results show that, without attenuator, dynamic range as high as 104 was achieved, with a scanning range of 126 ps and a temporal sampling interval of 6.3 fs. Moreover, the method suits for measuring laser pulse contrast in wide spectrum range. ? 2014 World Scientific Publishing Company.Accession Number: 20193607411667 -
Record 435 of
Title:Learning to resize image
Author(s):Wang, Qi(1); Yuan, Yuan(2)Source: Neurocomputing Volume: 131 Issue: DOI: 10.1016/j.neucom.2013.10.007 Published: May 5, 2014Abstract:Content-aware image resizing has been a promising theme in the communities of image processing and computer vision. To the best of our knowledge, most existing methods for image resizing are unsupervised. These unsupervised methods may either fail to protect the interesting regions or cause distortion of the image structure. This paper presents a novel learning based method for seam carving by incorporating the learned boundary of the important content. Specifically, a novel boundary model of the region of interest (ROI) is learned on a set of training images at first. Then the boundary of an input image is utilized as a key prior in performing seam carving to obtain the target image. The proposed method for image resizing can generate much less seams cutting through the ROI compared with previous efforts toward the same goal. Thus, the desirable regions can be preserved in the target image and the structural consistency of the input image is naturally maintained. Experiments on two publicly available data sets demonstrate the effectiveness of the proposed method. ? 2014.Accession Number: 20140817363967 -
Record 436 of
Title:High quality image resizing
Author(s):Wang, Qi(1); Yuan, Yuan(2)Source: Neurocomputing Volume: 131 Issue: DOI: 10.1016/j.neucom.2013.09.032 Published: May 5, 2014Abstract:An increasing amount of display devices with fixed sizes call for an adaptive strategy for optimal display. For this purpose, content aware image resizing techniques are developed. Previous works mainly lay their attention on the shrinkage operation of the examined image. Less efforts are paid on the expansion manipulation. Though some literatures claim an extension of their shrinkage operation to expanding the image in a similar way, the obtained results are not satisfying. In this paper, a high quality image resizing method is proposed to retain the details when stretching an image. Instead of using interpolation based techniques which are taken for granted by existing methods, an expansion model is first learned from a set of training images. Then the future enlargement is based on this principle. Experiments on two publicly available datasets demonstrate the effectiveness of the presented method. A further extension on video enlargement is also presented as an example. Though the proposed method is formulated in the context of seam carving, it can be readily extended to other techniques such as cropping, segmentation and warping based resizing methods. ? 2014.Accession Number: 20140817363966 -
Record 437 of
Title:Multi-cue based tracking
Author(s):Wang, Qi(1); Fang, Jianwu(2); Yuan, Yuan(2)Source: Neurocomputing Volume: 131 Issue: DOI: 10.1016/j.neucom.2013.10.021 Published: May 5, 2014Abstract:Visual tracking is a central topic in computer vision. However, the accurate localization of target object in extreme conditions (such as occlusion, scaling, illumination change, and shape transformation) still remains a challenge. In this paper, we explore utilizing multi-cue information to ensure a robust tracking. Optical flow, color and depth clues are simultaneously incorporated in our framework. The optical flow can get a rough estimation of the target location. Then the part-based structure is adopted to establish the precise position, combining both color and depth statistics. In order to validate the robustness of the proposed method, we take four video sequences of different demanding situations and compare our method with five competitive ones representing state of the arts. Experiments prove the effectiveness of the proposed method. ? 2013 Elsevier B.V.Accession Number: 20140817363955 -
Record 438 of
Title:Research on polarized scattering of self-organized nanogratings induced by femtosecond laser
Author(s):Xue, Jun(1); Yang, Yong(2); Li, Chen(2); Li, Dongjuan(2)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 34 Issue: 4 DOI: 10.3788/AOS201434.0432001 Published: April 2014Abstract:Experiments confirm that the femtosecond laser induced periodic nanogratings in a transparent material represents the novel optical properties. The scattering characteristics of nanogratings and nano-grating array are studied in detail by experiments and finite-difference time-domain (FDTD) respectively. Analysis result shows that scattering characteristics of nanogratings are sensitive to the polarization of the incident laser. For arrays of nanogratings, the scattering intensity in the laser polarization perpendicular to the nanograting is 20000 times larger than that in the laser polarization parallel to the nanograting. Morerover, the scattering intensity is dependent on the incident laser wavelength. The longer the wavelength is, the weaker the scattering intensity will be. The simulation results demonstrate that type II waveguide and the light polarized guide mechanism of nanograting are based on scattering characteristics of nanograting instead of birefringence effect theoretically.Accession Number: 20142117743290 -
Record 439 of
Title:Bound-state solitons in a linear-cavity fiber laser mode-locked by single-walled carbon nanotubes
Author(s):Guo, J.(1)Source: Journal of Modern Optics Volume: 61 Issue: 12 DOI: 10.1080/09500340.2014.916361 Published: July 12, 2014Abstract:The bound-state solitons generated from a nanotube-mode-locked linear-cavity fiber laser are experimentally observed and numerically simulated for the first time to authors best knowledge. Two chirped fiber Bragg gratings are exploited as the mirrors for the proposed laser. The pulse duration of solitons is about 6.3 ps and the pulse-to-pulse separation is about 23 ps in the experimental observations. Numerical simulations confirm the experimental results and agree well with the experimental observations. Both experimental and numerical results show that the bound-state solitons are strongly stable. ? 2014 Taylor and Francis.Accession Number: 20142717893469 -
Record 440 of
Title:The compensation of Y waveguide temperature drifts in FOG with the thermal resistor
Author(s):Wang, Ying Li(1); Ren, Li Yong(1); Xu, Jin Tao(1,2); Liang, Jian(1); Kang, Meng Hua(1,3); Ren, Kai Li(1,3); Shi, Nian Bao(1,2)Source: Advanced Materials Research Volume: 924 Issue: DOI: 10.4028/www.scientific.net/AMR.924.336 Published: 2014Abstract:The lithium niobate integrated optical phase modulator(Y waveguide) is the key device in the digital closed-loop fiber optic gyroscope. However, the half-wave voltage of the lithium niobate changes with the environment temperature, which produces the phase bias drift and ultimately decreases the accuracy of FOG. In this manuscript, the thermal resistor is introduced in the amplification part in the driving circuits of Y waveguide. Due to the characteristic of the thermal resistor, the magnitude of driving voltage on Y waveguide changed with temperature to compensate the electro-optic effect's temperature drift of the lithium niobate. This method was proved to improve the performance of fiber optic gyroscopes conveniently in experiment. ? (2014) Trans Tech Publications, Switzerland.Accession Number: 20142317800339 -
Record 441 of
Title:Design of vibration-insensitive Sagnac fiber-optic current sensors using spun high-birefringence fibers
Author(s):Kang, Meng-Hua(1,2); Wang, Ying-Li(1); Ren, Li-Yong(1); Xu, Jin-Tao(1,3); Liang, Jian(1); Qu, En-Shi(1)Source: Journal of Modern Optics Volume: 61 Issue: 14 DOI: 10.1080/09500340.2014.922630 Published: August 16, 2014Abstract:A novel fiber-optic current sensing element is proposed to enhance sensor performance using spun high-birefringence fibers. Such element includes three fiber sections. Two terminal sections with a varying spin rate along the fiber are utilized to replace the fiber quarter-wave plates, each converting the light polarization state from linear to circular and vice versa. The middle section with a uniform spin rate is utilized as the current sensing fiber that maintains the circular polarization state during the light propagation. The fiber is also wound into a special geometric structure so that the Sagnac phase shift can be inherently eliminated, and the sensing result does not depend on the position of the current conductor. The evolution of the light polarization state was analyzed using coupled-mode theory with different polarization state incidents in the sensing fiber. A sensor scheme based on this type of spun fiber is also proposed. ? 2014 Taylor & Francis.Accession Number: 20143017980199 -
Record 442 of
Title:Green, cubic Y2O3: Tb3+ nanospheres: Synthesis and photoluminescence property
Author(s):Miao, H.(1,2); Hu, X.(1,2); Sun, X.(1); Wang, Z.(1); Sun, Q.(1); Wu, H.(1); Zhang, D.(1,2); Bai, J.(1,2); Hou, X.(1,3)Source: Technical Proceedings of the 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014 Volume: 1 Issue: DOI: Published: 2014Abstract:In this study, Tb3+-doped Y2O3 green nanospheres were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The specimens annealed above 800° C are well matched with the cubic phase (JCPDS, 41-1105), and the crystallinity increases with raising the annealing temperature. All the as prepared samples consist of well separated spherical particles with diameter size varying from 200nm to 700nm. Obviously, the average size of the separated spherical particles decreases by the raising of the annealing temperature while the photoluminescence intensity excited by either 275nm or 300nm increases.Accession Number: 20143918183433 -
Record 443 of
Title:Adaptive Shape Prior Constrained Level Sets for Bladder MR Image Segmentation
Author(s):Qin, Xianjing(1); Li, Xuelong(2); Liu, Yang(3); Lu, Hongbing(3); Yan, Pingkun(1)Source: IEEE Journal of Biomedical and Health Informatics Volume: 18 Issue: 5 DOI: 10.1109/JBHI.2013.2288935 Published: September 2014Abstract:Three-dimensional bladder wall segmentation for thickness measuring can be very useful for bladder magnetic resonance (MR) image analysis, since thickening of the bladder wall can indicate abnormality. However, it is a challenging task due to the artifacts inside bladder lumen, weak boundaries in the apex and base areas, and complicated outside intensity distributions. To deal with these difficulties, in this paper, an adaptive shape prior constrained directional level set model is proposed to segment the inner and outer boundaries of the bladder wall. In addition, a coupled directional level set model is presented to refine the segmentation by exploiting the prior knowledge of region information and minimum thickness. With our proposed method, the influence of the artifacts in the bladder lumen and the complicated outside tissues surrounding the bladder can be appreciably reduced. Furthermore, the leakage on the weak boundaries can be avoided. Compared with other related methods, better results were obtained on 11 patients' 3-D bladder MR images by using the proposed method. ? 2013 IEEE.Accession Number: 20161302146698 -
Record 444 of
Title:Synthesis and optical properties of neodymium 4, 4'-dimethyl-2, 2'-bipyridine complex for liquid laser media
Author(s):Zhao, Peng-Fei(1); She, Jiang-Bo(1); Li, Dong-Dong(1,2); Nie, Rong-Zhi(1); Peng, Bo(1,3)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 2 DOI: 10.3788/gzxb20144302.0216001 Published: February 2014Abstract:A novel neodymium pentafluoropropionate complex, Nd(C2F5COO)3·Dmbp (Dmbp: 4, 4'-dimethyl-2, 2'-bipyridine), was synthesized and characterized by elemental analysis, Fourier transform infrared spectra. The optical porperties of the liquid medium which was abtained by dissolving Nd(C2F5COO)3·Dmbp in N, N-dimethylformamide was investigated. Based on absorption and luminescence spectra of Nd(C2F5COO)3·Dmbp in DMF, as well as Judd-Ofelt theory, the three intensity parameters Ωt(t=2, 4, 6) and emission cross-section were calculated and analyzed The emission cross-section of 4F3/2→4I11/2 fluorescence transition of Nd3+ion was 5.2×10-20cm2, and comparable with some laser glasses, which indicated good radiative properties of this neodymium complex in liquid matrix. According to the photoluminescence spectra, Nd(C2F5COO)3·Dmbp complex will be a promising material for optical gain material in the future.Accession Number: 20141217496716