2017

• Record 13 of
  
  Title:Meter-scale thin film coating equipment based on meniscus-coating technology
  
  Author(s):Xu, Jia(1); Xu, Wen-Bin(1); Bu, He-Yang(1); Lu, Zheng-Wu(1); Liu, Zheng-Kun(2); Hong, Yi-Lin(2); Yu, Wei-Xing(3)
  Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering  Volume: 25  Issue: 1  DOI: 10.3788/OPE.20172501.0133  Published: January 1, 2017  
  Abstract:The meniscus chemical coating technology becomes a very promising new chemical thin-film coating technology after traditional coating technologies such as spin-coating and spray coating due to its merits of large area, low-cost and high efficiency. To meet the requirements of one national major projects on the meter-scale chemical thin film coating of optical component surface, based on the systematical research of the meniscus chemical film coating principal, static and dynamic gluing experiments were respectively conducted, and the relationships among the gluing pressure, the gap between substrate and slit, the material hydrophobicity and the morphology of meniscus were analyzed, then the fine tuning of the meniscus could be achieved and equipment based on the meniscus chemical thin film coating technology was developed. The coating uniformity of photo-resist was realized using this equipment on the glass substrate sizing 1400 mm×420 mm, making overall coating thickness error less than 4% and satisfying coating requirements of meter-scale chemical precision thin film coating of optical component surface. © 2017, Science Press. All right reserved.
  Accession Number: 20172203698751
• Record 14 of
  
  Title:Learning bregman distance functions for structural learning to rank
  
  Author(s):Li, Xi(1,2); Pi, Te(3); Zhang, Zhongfei(3); Zhao, Xueyi(3); Wang, Meng(4); Li, Xuelong(5); Yu, Philip S.(6)
  Source: IEEE Transactions on Knowledge and Data Engineering  Volume: 29  Issue: 9  DOI: 10.1109/TKDE.2017.2654250  Published: September 1, 2017  
  Abstract:We study content-based learning to rank from the perspective of learning distance functions. Standardly, the two key issues of learning to rank, feature mappings and score functions, are usually modeled separately, and the learning is usually restricted to modeling a linear distance function such as the Mahalanobis distance. However, the modeling of feature mappings and score functions are mutually interacted, and the patterns underlying the data are probably complicated and nonlinear. Thus, as a general nonlinear distance family, the Bregman distance is a suitable distance function for learning to rank, due to its strong generalization ability for distance functions, and its nonlinearity for exploring the general patterns of data distributions. In this paper, we study learning to rank as a structural learning problem, and devise a Bregman distance function to build the ranking model based on structural SVM. To improve the model robustness to outliers, we develop a robust structural learning framework for the ranking model. The proposed model Robust Structural Bregman distance functions Learning to Rank (RSBLR) is a general and unified framework for learning distance functions to rank. The experiments of data ranking on real-world datasets show the superiority of this method to the state-of-the-art literature, as well as its robustness to the noisily labeled outliers. © 1989-2012 IEEE.
  Accession Number: 20173804172835
• Record 15 of
  
  Title:A Biologically Inspired Appearance Model for Robust Visual Tracking
  
  Author(s):Zhang, Shengping(1); Lan, Xiangyuan(2); Yao, Hongxun(1); Zhou, Huiyu(3); Tao, Dacheng(4); Li, Xuelong(5)
  Source: IEEE Transactions on Neural Networks and Learning Systems  Volume: 28  Issue: 10  DOI: 10.1109/TNNLS.2016.2586194  Published: October 2017  
  Abstract:In this paper, we propose a biologically inspired appearance model for robust visual tracking. Motivated in part by the success of the hierarchical organization of the primary visual cortex (area V1), we establish an architecture consisting of five layers: Whitening, rectification, normalization, coding, and pooling. The first three layers stem from the models developed for object recognition. In this paper, our attention focuses on the coding and pooling layers. In particular, we use a discriminative sparse coding method in the coding layer along with spatial pyramid representation in the pooling layer, which makes it easier to distinguish the target to be tracked from its background in the presence of appearance variations. An extensive experimental study shows that the proposed method has higher tracking accuracy than several state-of-the-art trackers. © 2012 IEEE.
  Accession Number: 20163002643529
• Record 16 of
  
  Title:Demonstration of a mid-infrared NO molecular Faraday optical filter
  
  Author(s):Wu, Kuijun(1); Feng, Yutao(2); Li, Juan(2); Yu, Guangbao(1); Liu, Linmei(1); Xiong, Yuanhui(1); Li, Faquan(1)
  Source: Optics Express  Volume: 25  Issue: 25  DOI: 10.1364/OE.25.030916  Published: December 11, 2017  
  Abstract:A molecular Faraday optical filter (MFOF) working in the mid-infrared region is realized for the first time. NO molecule was used as the working material of the MFOF for potential applications in atmospheric remote sensing and combustion diagnosis. We develop a complete theory to describe the performance of MFOF by taking both Zeeman absorption and Faraday rotation into account. We also record the Faraday rotation transmission (FRT) signal using a quantum cascade laser over the range of 1,820 cm−1 to 1,922 cm−1 and calibrate it by using a 101.6 mm long solid germanium etalon with a free spectral range of 0.012 cm−1. Good agreement between the simulation results and experimental data is achieved. The NO-MFOF’s transmission characteristics as a function of magnetic field and pressure are studied in detail. Both Comb-like FRT spectrum and single branch transmission spectrum are obtained by changing the magnetic field. The diversity of FRT spectrum expands the range of potential applications in infrared optical remote sensing. This filtering method can also be extended to the lines of other paramagnetic molecules. © 2017 Optical Society of America.
  Accession Number: 20175104558227
• Record 17 of
  
  Title:High peak power actively Q-switched mid-infrared fiber lasers at 3 μm
  
  Author(s):Shen, Yanlong(1,2,3,4); Wang, Yishan(1,5); Luan, Kunpeng(3); Chen, Hongwei(3); Tao, Mengmeng(3); Si, Jinhai(2)
  Source: Applied Physics B: Lasers and Optics  Volume: 123  Issue: 4  DOI: 10.1007/s00340-017-6684-0  Published: April 1, 2017  
  Abstract:Diode-pumped pulsed Er3+-doped ZBLAN fiber lasers at 2.8 μm actively Q-switched by using an mechanical Q-switch with feedbacks of a protected gold mirror and a blazing grating were investigated, respectively. A pulse energy of 0.13 mJ and repetition rate of 10 kHz with a pulse width of 127.3 ns at 2.78 μm was obtained when using a protected gold mirror as the feedback. By replacing the mirror with a blazing grating in Littrow configuration, the wavelength of the Q-switched pulse train was tunable with over 100 nm tuning range from 2.71 to 2.82 μm and a linewidth of ~1.5 nm. A maxinmum pulse energy of up to 0.15 mJ and repetition rate of 10 kHz with a pulse width of 92.6 ns was achieved, yielding the maximum peak power of exceeding 1.6 kW. The pulse energy and peak power, to our knowledge, are the highest ever reported in the mid-infrared Q-switched fiber lasers. © 2017, Springer-Verlag Berlin Heidelberg.
  Accession Number: 20171303505688
• Record 18 of
  
  Title:Orthogonal self-guided similarity preserving projection for classification and clustering
  
  Author(s):Fang, Xiaozhao(1); Xu, Yong(2); Li, Xuelong(3); Lai, Zhihui(4); Teng, Shaohua(1); Fei, Lunke(2)
  Source: Neural Networks  Volume: 88  Issue:   DOI: 10.1016/j.neunet.2017.01.001  Published: April 1, 2017  
  Abstract:A suitable feature representation can faithfully preserve the intrinsic structure of data. However, traditional dimensionality reduction (DR) methods commonly use the original input features to define the intrinsic structure, which makes the estimated intrinsic structure unreliable since redundant or noisy features may exist in the original input features. Thus a dilemma is that (1) one needs the most suitable feature representation to define the intrinsic structure of data and (2) one should use the proper intrinsic structure of data to perform feature extraction. To address the problem, in this paper we propose a unified learning framework to simultaneously obtain the optimal feature representation and intrinsic structure of data. The structure is learned from the results of feature learning, and the features are learned to preserve the refined structure of data. By leveraging the interactions between the process of determining the most suitable feature representation and intrinsic structure of data, we can capture accurate structure and obtain the optimal feature representation of data. Experimental results demonstrate that our method outperforms state-of-the-art methods in DR and subspace clustering. The code of the proposed method is available at "http://www.yongxu.org/lunwen.html ". © 2017 Elsevier Ltd
  Accession Number: 20170703355404
• Record 19 of
  
  Title:SCECam: a spherical compound eye camera for fast location and recognition of objects at a large field of view
  
  Author(s):Shi, Chengyong(1,2); Wang, Yuanyuan(1,2); Liu, Chenyang(1,2); Wang, Taisheng(1); Zhang, Hongxin(1); Liao, Wuxia(3); Xu, Zhijun(1); Yu, Weixing(4)
  Source: Optics Express  Volume: 25  Issue: 26  DOI: 10.1364/OE.25.032333  Published: December 25, 2017  
  Abstract:In recent years, the compound eye imaging system has attracted great attention due to its fascinating optical features such as large field of view (FOV), small volume and high acuity to moving objects. However, it is still a big challenge to fabricate such a whole system due to the mismatch between the spherical compound eye imaging element and the planar imaging sensor. In this work, we demonstrate a kind of hemispherical compound eye camera (SCECam) which analogs the eye of the fruit fly. The SCECam consists of three sub-systems, a hemispherical compound eye, an optical relay system and a commercial CMOS imaging sensor. By introducing an intermediate optical relay system, the curved focal plane after the compound eye can be transformed and projected onto the planar focal plane of the imaging sensor. In this way, the SCECam can realize a large FOV (up to 122.4°) with 4400 ommatidia, which makes it possible to detect and locate fast moving objects at a very fast speed. It is calculated that the recognition speed of the SCECam is two to three orders of magnitude higher than those conventional methods such as the Canny and Log edge-detection methods. © 2017 Optical Society of America.
  Accession Number: 20175204584523
• Record 20 of
  
  Title:Wavelength conversion of QAM signals in a low loss CMOS compatible spiral waveguide
  
  Author(s):Da Ros, Francesco(1); Porto Da Silva, Edson(1); Zibar, Darko(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4,5,6); Galili, Michael(1); Moss, David J.(7); Oxenløwe, Leif K.(1)
  Source: APL Photonics  Volume: 2  Issue: 4  DOI: 10.1063/1.4978945  Published: April 1, 2017  
  Abstract:We demonstrate wavelength conversion of quadrature amplitude modulation (QAM) signals, including 32-GBd quadrature phase-shift keying and 10-GBd 16-QAM, in a 50-cm long high index doped glass spiral waveguide. The quality of the generated idlers for up to 20 nm of wavelength shift is sufficient to achieve a BER performance below the hard decision forward error correction threshold BER performance (3), with an optical signal-to-noise ratio penalty of less than 0.3 dB compared to the original signal. Our results confirm that this is a promising platform for nonlinear optical signal processing, as a result of both very low linear propagation loss ( © 2017 Author(s).
  Accession Number: 20173504094985
• Record 21 of
  
  Title:Person re-identification by multi-hypergraph fusion
  
  Author(s):An, Le(1); Chen, Xiaojing(2); Yang, Songfan(3); Li, Xuelong(4)
  Source: IEEE Transactions on Neural Networks and Learning Systems  Volume: 28  Issue: 11  DOI: 10.1109/TNNLS.2016.2602082  Published: November 2017  
  Abstract:Matching people across nonoverlapping cameras, also known as person re-identification, is an important and challenging research topic. Despite its great demand in many crucial applications such as surveillance, person re-identification is still far from being solved. Due to drastic view changes, even the same person may look quite dissimilar in different cameras. Illumination and pose variations further aggravate this discrepancy. To this end, various feature descriptors have been designed for improving the matching accuracy. Since different features encode information from different aspects, in this paper, we propose to effectively leverage multiple off-the-shelf features via multi-hypergraph fusion. A hypergraph captures not only pairwise but also high-order relationships among the subjects being matched. In addition, different from conventional approaches in which the matching is achieved by computing the pairwise distance or similarity between a probe and a gallery subject, the similarities between the probe and all gallery subjects are learned jointly via hypergraph optimization. Experiments on popular data sets demonstrate the effectiveness of the proposed method, and a superior performance is achieved as compared with the most recent state-of-the-arts. © 2016 IEEE.
  Accession Number: 20174904514012
• Record 22 of
  
  Title:Harnessing optical micro-combs for microwave photonics
  
  Author(s):Wu, Jiayang(1); Xu, Xingyuan(1); Nguyen, Thach G.(2); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)
  Source: arXiv  Volume:   Issue:   DOI:   Published: October 24, 2017  
  Abstract:In the past decade, optical frequency combs generated by high-Q micro-resonators, or micro-combs, which feature compact device footprints, high energy efficiency, and high-repetition-rates in broad optical bandwidths, have led have led have led have led have led have led have led have led have led to ato ato ato a revolutionrevolutionrevolutionrevolutionrevolutionrevolution revolutionrevolutionrevolution in in in a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields a wide range of fields includingincludingincludingincludingincluding includingincludingincluding metrology, mode-locked lasers, telecommunications, RF photonics, spectroscopy, sensing, and quantum optics. Among these, an application that has attracted great interest is the use of micro-combs for RF photonics, where they offer enhanced functionalities as well as reduced size and power consumption over other approaches. This article reviews the recent advances in this emerging field. We provide an overview of the main achievements that have been obtained to date, and highlight the strong potential of micro-combs for RF photonics applications. We also discuss some of the open challenges and limitations that need to be met for practical applications. Copyright © 2017, The Authors. All rights reserved.
  Accession Number: 20200501272
• Record 23 of
  
  Title:An optical micro-comb with a 50GHz free spectral range for photonic microwave true time delays
  
  Author(s):Xu, Xingyuan(1); Wu, Jiayang(1); Nguyen, Thach G.(2); Moein, Tania(1); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)
  Source: arXiv  Volume:   Issue:   DOI:   Published: October 29, 2017  
  Abstract:We demonstrate significantly improved performance of a microwave true time delay line (TTDL) based on an integrated micro-ring resonator (MRR) Kerr optical comb source with a channel spacing of 49GHz, corresponding to 81 channels over the C-band. The broadband microcomb, with a record low free spectral range of 49GHz, results in a large number of comb lines for the TTDL, greatly reducing the size, cost, and complexity of the system. The large channel count results in a high angular resolution and wide beam steering tunable range of the phased array antenna (PAA). The enhancement of PAA's performance matches well with theory, corroborating the feasibility of our approach as a competitive solution towards implementing compact low-cost TTDL in radar and communications systems. Copyright © 2017, The Authors. All rights reserved.
  Accession Number: 20200376098
• Record 24 of
  
  Title:Photonic radio frequency and microwave intensity differentiator based on an optical frequency comb source in an integrated micro-ring resonator
  
  Author(s):Xu, Xingyuan(1); Wu, Jiayang(1); Shoeiby, Mehrdad(2); Nguyen, Thach G.(2); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)
  Source: arXiv  Volume:   Issue:   DOI:   Published: September 26, 2017  
  Abstract:We propose and experimentally demonstrate a microwave photonic intensity differentiator based on a Kerr optical comb generated by a compact integrated micro-ring resonator (MRR). The on-chip Kerr optical comb, containing a large number of comb lines, serves as a high-performance multi-wavelength source for implementing a transversal filter, which will greatly reduce the cost, size, and complexity of the system. Moreover, owing to the compactness of the integrated MRR, frequency spacings of up to 200-GHz can be achieved, enabling a potential operation bandwidth of over 100 GHz. By programming and shaping individual comb lines according to calculated tap weights, a reconfigurable intensity differentiator with variable differentiation orders can be realized. The operation principle is theoretically analyzed, and experimental demonstrations of first-, second-, and third-order differentiation functions based on this principle are presented. The radio frequency (RF) amplitude and phase responses of multi-order intensity differentiations are characterized, and system demonstrations of real-time differentiations for a Gaussian input signal are also performed. The experimental results show good agreement with theory, confirming the effectiveness of our approach. Copyright © 2017, The Authors. All rights reserved.
  Accession Number: 20200522183