2011
2011
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Record 193 of
Title:Target-oriented shape modeling with structure constraint for image segmentation
Author(s):Zhang, Wuxia(1,2); Yuan, Yuan(1); Li, Xuelong(1); Yan, Pingkun(1)Source: 1st Asian Conference on Pattern Recognition, ACPR 2011 Volume: Issue: DOI: 10.1109/ACPR.2011.6166707 Published: 2011Abstract:Image segmentation plays a critical role in medical imaging applications, whereas it is still a challenging problem due to the complex shapes and complicated texture of structures in medical images. Model based methods have been widely used for medical image segmentation as a priori knowledge can be incorporated. Accurate shape prior estimation is one of the major factors affecting the accuracy of model based segmentation methods. This paper proposes a novel statistical shape modeling method, which aims to estimate target-oriented shape prior by applying the constraint from the intrinsic structure of the training shape set. The proposed shape modeling method is incorporated into a deformable model based framework for image segmentation. The experimental results showed that the proposed method can achieve more accurate segmentation compared with other existing methods. ? 2011 IEEE.Accession Number: 20122715188610 -
Record 194 of
Title:Clock drift-tolerant optical bit pattern monitoring technique in asynchronous undersampling system
Author(s):Zhang, Huixing(1,2); Zhao, Wei(1)Source: Optical Engineering Volume: 50 Issue: 10 DOI: 10.1117/1.3640828 Published: 2011Abstract:Based on an asynchronously undersampling system, we present a novel bit pattern monitoring technique in terms of its performance analysis and the implementation aspects. Relying upon an finite impulse response (FIR) filter assisted fine synchronization of the acquired samples, the technique can significantly reduce the random walk clock drift between data signal and sampling source compared to a conventional fine synchronization using a fixed time step. For the performance analysis of this technique, we first present an intuitive understanding of the principle of the FIR filter method under consideration of the filter frequency response. We find that the frequency response of the FIR filter simply serves to extract the spectral component at the aliasing frequency found in the periodogram and diminish all other frequency components. Then we test the tracking limit and discuss the optimized filter length choice of the new bit pattern monitoring technique through numerical examples. It turns out that the optimal filter length is chosen as the one which minimized the measured jitter and can be found iteratively. Finally, we present an experimental verification of this FIR bit pattern synchronization method by measuring and reconstructing bit patterns of 40 Gb/s nonreturn-to-zero and 160 Gb/s return-to-zero data signals, respectively. ? 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).Accession Number: 20134316893751 -
Record 195 of
Title:Synthesis, crystal structure and photophysical properties of a neodymium trifluoroacetate complex with 2,2'-bipyridine
Author(s):She, Jiangbo(1); Li, Dongdong(1); Hou, Chaoqi(1,2); Yang, Wenzheng(1); Wei, Wei(2); Peng, Bo(1,2)Source: Journal of Rare Earths Volume: 29 Issue: 3 DOI: 10.1016/S1002-0721(10)60429-2 Published: March 2011Abstract:The neodymium trifluoroacetate complexes were synthesized and characterized by single-crystal X-ray diffraction for [Nd(CF3COO) 3·Bpy·(H2O)3]Bpy (1), elemental and TG analysis, FT-IR spectra, and PL spectra for Nd(CF3COO) 3·Bpy (2) (Bpy: 2,2'-bipyridine). The most interesting feature of the crystal structure for 1 is that it comprises a coordinated 2,2'-bipyridine molecule and an out-sphere 2,2'-bipyridine molecule. At the same time, the C-O distances appeared average which indicates the three atoms of carboxylato forming electron-conjugate system. Hydrogen bond and p-p-stacking link the binuclear to two-dimensional sheet. The optical spectra for 2 exhibited that the complex possessed typical Nd (III) ion absorption and photoluminescence emission. The emission cross-section of 4F 3/2→4I11/2 fluorescence transition (3.63×10-20 cm2) was comparable with some laser glasses, which indicated good radiative properties of this neodymium trifluoroacetate complex in liquid matrix. The thermal analysis indicated that it was quite stable to heat. ? 2011 The Chinese Society of Rare Earths.Accession Number: 20111513904131 -
Record 196 of
Title:Design of Topas microstructured fiber with ultra-flattened chromatic dispersion and high birefringence
Author(s):Wang, Doudou(1,2); Wang, Lili(1)Source: Optics Communications Volume: 284 Issue: 24 DOI: 10.1016/j.optcom.2011.08.040 Published: December 1, 2011Abstract:A microstructured polymer optical fiber (mPOF) with both ultra-flattened near-zero chromatic dispersion and high birefringence based on Topas cyclic olefin copolymer is designed. Three rings of uniform elliptical air holes are arranged in triangular lattice in the cladding and an extra small defected hole is introduced in the fiber core. Guided modes, dispersion, birefringence and mode confinement properties of the designed mPOF are investigated by using the full-vector finite element method. Dispersion values between ± 0.5 ps/km/nm over the wavelength 1.1-1.7 μm and high birefringence of the order of 10-3 are obtained for the optimized fiber structure. Low confinement losses and small effective mode area are obtained at the same time. The relatively simple architecture of the proposed Topas mPOF can be fabricated by our extrusion-stretching techniques. ? 2011 Elsevier B.V. All rights reserved. ? 2011 Elsevier B.V. All rights reserved.Accession Number: 20114114424013 -
Record 197 of
Title:Highly flexible all-optical metamaterial absorption switching assisted by Kerr-nonlinear effect
Author(s):Gong, Yongkang(1); Li, Zhiyuan(2); Fu, Jinxin(2); Chen, Yuhui(2); Wang, Guoxi(1); Lu, Hua(1); Wang, Leirang(1); Liu, Xueming(1)Source: Optics Express Volume: 19 Issue: 11 DOI: 10.1364/OE.19.010193 Published: May 23, 2011Abstract:A three-dimensional metamaterial nanostructure for realizing all-optical absorption switching is proposed and investigated. The structure consists of dual metallic layers for allowing near-perfect absorption due to electric and magnetic resonances, and a nonlinear Kerr-dielectric layer for actively manipulating the nanostructure absorption. The finite-difference time-domain simulation results demonstrate that, by adjusting the incident optical intensity, the metamaterial absorption can be flexibly tuned from near unity to zero. The all-optical absorption switching structure can find potential applications in actively integrated photonic circuits for thermal sensing, photo detecting, and optical imaging. ? 2011 Optical Society of America.Accession Number: 20112214020152 -
Record 198 of
Title:Local semi-supervised regression for single-image super-resolution
Author(s):Tang, Yi(1); Pan, Xiaoli(2); Yuan, Yuan(1); Yan, Pingkun(1); Li, Luoqing(2); Li, Xuelong(1)Source: MMSP 2011 - IEEE International Workshop on Multimedia Signal Processing Volume: Issue: DOI: 10.1109/MMSP.2011.6093842 Published: 2011Abstract:In this paper, we propose a local semi-supervised learning-based algorithm for single-image super-resolution. Different from most of example-based algorithms, the information of test patches is considered during learning local regression functions which map a low-resolution patch to a high-resolution patch. Localization strategy is generally adopted in single-image super-resolution with nearest neighbor-based algorithms. However, the poor generalization of the nearest neighbor estimation decreases the performance of such algorithms. Though the problem can be fixed by local regression algorithms, the sizes of local training sets are always too small to improve the performance of nearest neighbor-based algorithms significantly. To overcome the difficulty, the semi-supervised regression algorithm is used here. Unlike supervised regression, the information about test samples is considered in semi-supervised regression algorithms, which makes the semi-supervised regression more powerful. Noticing that numerous test patches exist, the performance of nearest neighbor-based algorithms can be further improved by employing a semi-supervised regression algorithm. Experiments verify the effectiveness of the proposed algorithm. ? 2011 IEEE.Accession Number: 20115214632537 -
Record 199 of
Title:Utilizing homotopy for single image superresolution
Author(s):Lu, Xiaoqiang(1); Yan, Pingkun(1); Yuan, Yuan(1); Li, Xuelong(1); Yuan, Haoliang(2)Source: 1st Asian Conference on Pattern Recognition, ACPR 2011 Volume: Issue: DOI: 10.1109/ACPR.2011.6166654 Published: 2011Abstract:Learning an appropriate dictionary is a critical issue for sparse representation based super-resolution algorithms. A good dictionary can well represent an underlying image. In super-resolution algorithms, classical dictionary learning doesn't consider the information of test image which contains the information of the reconstructed image. In this paper, the new dictionary is design for image super-resolution, incorporating both training image patches and test image patches for training. It is important for dictionary learning to adaptively choose the training image patches and test image patches which effectively represent the reconstructed image structures. In the new learning strategy, a homotopy method is applied to choose the parameter that yields a proper balance between the use of training image patches and test image patches. The homotopy method is used to track the homotopy path leading to the solution to the desired problem at the terminal point. Compared with other state-of-the-art learning methods, our algorithm learns an over-complete dictionary by exploiting the information of the given test image and training images. The experimental results show that the proposed method is able to achieve better experimental results in terms of both PSNR and visual perception. ? 2011 IEEE.Accession Number: 20122715188557 -
Record 200 of
Title:Transfer latent variable model based on divergence analysis
Author(s):Gao, Xinbo(1); Wang, Xiumei(1); Li, Xuelong(2); Tao, Dacheng(3)Source: Pattern Recognition Volume: 44 Issue: 10-11 DOI: 10.1016/j.patcog.2010.06.013 Published: October-November 2011Abstract:Latent variable models are powerful dimensionality reduction approaches in machine learning and pattern recognition. However, this kind of methods only works well under a necessary and strict assumption that the training samples and testing samples are independent and identically distributed. When the samples come from different domains, the distribution of the testing dataset will not be identical with the training dataset. Therefore, the performance of latent variable models will be degraded for the reason that the parameters of the training model do not suit for the testing dataset. This case limits the generalization and application of the traditional latent variable models. To handle this issue, a transfer learning framework for latent variable model is proposed which can utilize the distance (or divergence) of the two datasets to modify the parameters of the obtained latent variable model. So we do not need to rebuild the model and only adjust the parameters according to the divergence, which will adopt different datasets. Experimental results on several real datasets demonstrate the advantages of the proposed framework. ? 2010 Elsevier Ltd. All rights reserved.Accession Number: 20112514071838 -
Record 201 of
Title:Synthesis and saturable absorption of graphene with wet-chemistry techniques
Author(s):Wang, Jin(1); Li, Ning(1); Liu, Chunxiao(1); Zhou, Yan(1); Wei, Wei(1,2); Peng, Bo(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 31 Issue: SUPPL.1 DOI: 10.3788/AOS201131.s100106 Published: June 2011Abstract:A graphene-water solution and graphene-polyvinyl alcohol composite are fabricated from graphite by wet-chemistry techniques. The research shows that both of graphene solutions and the composite have saturable absorption ability. The atomic layer grapheme possesses wavelength-independent ultrafast saturable absorption, which can be realized mode-locking in a large-wide-range wavelength. The cost of the atomic layer graphene is far lower than that of semiconductor saturable absorber mirror (SESAM) as a mode-locker.Accession Number: 20113114199055 -
Record 202 of
Title:Local learning-based image super-resolution
Author(s):Lu, Xiaoqiang(1); Yuan, Haoliang(2); Yuan, Yuan(1); Yan, Pingkun(1); Li, Luoqing(2); Li, Xuelong(1)Source: MMSP 2011 - IEEE International Workshop on Multimedia Signal Processing Volume: Issue: DOI: 10.1109/MMSP.2011.6093843 Published: 2011Abstract:Local learning algorithm has been widely used in single-frame super-resolution reconstruction algorithm, such as neighbor embedding algorithm [1] and locality preserving constraints algorithm [2]. Neighbor embedding algorithm is based on manifold assumption, which defines that the embedded neighbor patches are contained in a single manifold. While manifold assumption does not always hold. In this paper, we present a novel local learning-based image single-frame SR reconstruction algorithm with kernel ridge regression (KRR). Firstly, Gabor filter is adopted to extract texture information from low-resolution patches as the feature. Secondly, each input low-resolution feature patch utilizes K nearest neighbor algorithm to generate a local structure. Finally, KRR is employed to learn a map from input low-resolution (LR) feature patches to high-resolution (HR) feature patches in the corresponding local structure. Experimental results show the effectiveness of our method. ? 2011 IEEE.Accession Number: 20115214632538 -
Record 203 of
Title:Fabrication and characterization of a water-free mid-infrared fluorotellurite glass
Author(s):Lin, Aoxiang(1,2); Ryasnyanskiy, Aleksandr(1); Toulouse, Jean(1)Source: Optics Letters Volume: 36 Issue: 5 DOI: 10.1364/OL.36.000740 Published: March 1, 2011Abstract:Using a physical and chemical dehydration technique and a high-pressure, ultradry O2 atmosphere in a semiclosed steel-chamber furnace, we fabricated a group of fluorotellurite glasses with a composition of (90-x) TeO2-xZnF2-10Na2O (mol.%, x = 0-30). For x = 30, no OH absorption was observed in the range of 0.38-6.1μm. This is the first report of a water-free mid-IR fluorotellurite glass, to our knowledge, offering the common advantages of a robust oxide glass and an IR-transparent fluoride one. Besides optimized linear transmittance and absorption, the nonlinear refractive indices and Raman gain coefficients are reduced. These results are discussed in the context of mid-IR high-power laser generation and transmission. ? 2011 Optical Society of America.Accession Number: 20111013735010 -
Record 204 of
Title:Tunable third-harmonic generation in a solid-core tellurite glass fiber
Author(s):Lin, Aoxiang(1,2); Ryasnyanskiy, Aleksandr(1); Toulouse, Jean(1)Source: Optics Letters Volume: 36 Issue: 17 DOI: 10.1364/OL.36.003437 Published: September 1, 2011Abstract:A solid-core tellurite glass fiber with 1.8 dB/m loss at 1.55 μm was made by using the built-in casting preform fabrication method and rod-in-tube fiber drawing technique. Pumping a 10cm fiber piece with picosecond pulses of 3-5 × 1012 W/cm2, 0.1% of the fundamental power limited by the coherence length of 0.3-5 μm was converted into visible third-harmonic power tunable over a broad near-IR wavelength ranging from 1500 to 1680nm. Frequency conversion from the mid-IR to near-IR was found to be even more efficient due to the longer coherence lengths of 12-20 μm in the wavelength range of 2200-2500nm. ? 2011 Optical Society of America.Accession Number: 20113714319559