2017
2017
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Record 361 of
Title:Multiple Auxiliaries Assisted Airborne Power Line Detection
Author(s):Shan, Haotian(1); Zhang, Jun(1); Cao, Xianbin(1); Li, Xuelong(2); Wu, Dapeng(1,3)Source: IEEE Transactions on Industrial Electronics Volume: 64 Issue: 6 DOI: 10.1109/TIE.2017.2668994 Published: June 2017Abstract:Airborne power line detection is a key technique to ensure low altitude flight safety. Yet, it is a challenging problem due to the extremely small size of power line targets. Recently, auxiliary assisted detection has shown great potential in improving the power line detection performance. However, in existing methods, the auxiliaries and the contexts between the power lines and the auxiliaries are both manually assigned, thus limits its applicability. In this paper, a novel multiple auxiliaries assisted power line detection method is proposed. With an optimization based auxiliaries selection and contexts acquisition scheme, the proposed method cannot only decide which auxiliaries should be selected to assist the detection, but also acquire the context information of each kind of auxiliaries, all in an automatic way. Experimental results show that the proposed method surpasses the state-of-the-art power line detection methods, both in terms of detection accuracy and false alarm probability. ? 2017 IEEE.Accession Number: 20173604133286 -
Record 362 of
Title:Design of high precision temperature control system for to packaged LD
Author(s):Liang, Enji(1,2); Luo, Baoke(1); Zhuang, Bin(1); He, Zhengquan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10458 Issue: DOI: 10.1117/12.2283461 Published: 2017Abstract:Temperature is an important factor affecting the performance of TO package LD. In order to ensure the safe and stable operation of LD, a temperature control circuit for LD based on PID technology is designed. The MAX1978 and an external PID circuit are used to form a control circuit that drives the thermoelectric cooler (TEC) to achieve control of temperature and the external load can be changed. The system circuit has low power consumption, high integration and high precision,and the circuit can achieve precise control of the LD temperature. Experiment results show that the circuit can achieve effective and stable control of the laser temperature. ? 2017 SPIE.Accession Number: 20180304653911 -
Record 363 of
Title:Heterogeneous Face Recognition: A Common Encoding Feature Discriminant Approach
Author(s):Gong, Dihong(1); Li, Zhifeng(1); Huang, Weilin(1); Li, Xuelong(2); Tao, Dacheng(3)Source: IEEE Transactions on Image Processing Volume: 26 Issue: 5 DOI: 10.1109/TIP.2017.2651380 Published: May 2017Abstract:Heterogeneous face recognition is an important, yet challenging problem in face recognition community. It refers to matching a probe face image to a gallery of face images taken from alternate imaging modality. The major challenge of heterogeneous face recognition lies in the great discrepancies between different image modalities. Conventional face feature descriptors, e.g., local binary patterns, histogram of oriented gradients, and scale-invariant feature transform, are mostly designed in a handcrafted way and thus generally fail to extract the common discriminant information from the heterogeneous face images. In this paper, we propose a new feature descriptor called common encoding model for heterogeneous face recognition, which is able to capture common discriminant information, such that the large modality gap can be significantly reduced at the feature extraction stage. Specifically, we turn a face image into an encoded one with the encoding model learned from the training data, where the difference of the encoded heterogeneous face images of the same person can be minimized. Based on the encoded face images, we further develop a discriminant matching method to infer the hidden identity information of the cross-modality face images for enhanced recognition performance. The effectiveness of the proposed approach is demonstrated (on several public-domain face datasets) in two typical heterogeneous face recognition scenarios: matching NIR faces to VIS faces and matching sketches to photographs. ? 1992-2012 IEEE.Accession Number: 20171703602836 -
Record 364 of
Title:Multispectral image compression algorithm based on spectral clustering and wavelet transform
Author(s):Huang, Rong(1,2); Qiao, Weidong(2); Yang, Jianfeng(2); Wang, Hong(1,2); Xue, Bin(2); Tao, Jinyou(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10605 Issue: DOI: 10.1117/12.2292014 Published: 2017Abstract:In this paper, a method based on spectral clustering and the discrete wavelet transform (DWT) is proposed, which is based on the problem of the high degree of space-time redundancy in the current multispectral image compression algorithm. First, the spectral images are grouped by spectral clustering methods, and the clusters of similar heights are grouped together to remove the redundancy of the spectra. Then, wavelet transform and coding of the class representative are performed, and the space redundancy is eliminated, and the difference composition is applied to the Karhunen-Loeve transform (KLT) and wavelet transform. Experimental results show that with JPEG2000 and upon KLT + DWT algorithm, compared with the method has better peak signal-to-noise ratio and compression ratio, and it is suitable for compression of different spectral bands. ? 2017 SPIE.Accession Number: 20181705046884 -
Record 365 of
Title:A calibration mechanism based on worm drive for space telescope
Author(s):Chong, Yaqin(1,2); Li, Chuang(1); Xia, Siyu(1); Zhong, Peifeng(1,2); Lei, Wang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10339 Issue: DOI: 10.1117/12.2269878 Published: 2017Abstract:In this paper, a new type of calibration mechanism based on worm drive is presented for a space telescope. This calibration mechanism based on worm drive has the advantages of compact size and self-lock. The mechanism mainly consists of thirty-six LEDs as the light source for flat calibration, a diffuse plate, a step motor, a worm gear reducer and a potentiometer. As the main part of the diffuse plate, a PTFE tablet is mounted in an aluminum alloy frame. The frame is fixed on the shaft of the worm gear, which is driven by the step motor through the worm. The shaft of the potentiometer is connected to that of the worm gear to measure the rotation angle of the diffuse plate through a flexible coupler. Firstly, the calibration mechanism is designed, which includes the LEDs assembly design, the worm gear reducer design and the diffuse plate assembly design. The counterweight blocks and two end stops are also designed for the diffuse plate assembly. Then a modal analysis with finite element method for the diffuse plate assembly is completed. ? 2017 SPIE.Accession Number: 20173904206114 -
Record 366 of
Title:A diffuse plasma jet generated from the preexisting discharge filament at atmospheric pressure
Author(s):Li, Jing(1,2,3); Xu, Yonggang(1,2); Zhang, Tongyi(1,2); Tang, Jie(1,2); Wang, Yishan(1,2); Zhao, Wei(1,2); Duan, Yixiang(1,2,4)Source: Journal of Applied Physics Volume: 122 Issue: 1 DOI: 10.1063/1.4989975 Published: July 7, 2017Abstract:A diffuse plasma jet was realized by expanding the preexisting argon filamentary discharge into a diffuse one at atmospheric pressure. Examination of emission spectra from the plasma jet shows that the emission intensities of OH and Ar increase with the argon flow near the quartz tube nozzle, while the N2 emission intensity first increases, then decreases, and finally approximately remains unchanged with the increase in the argon flow of interest. It is also found that with the argon flow set at 0.4 l/min, most of the reactive species are gathered close to the nozzle, the OH and Ar emission intensities decrease quickly after the plasma propagates out of the nozzle, but the N2 emission is able to propagate over a larger distance. These distinct spectral emission features of OH, N2, and Ar are attributed to the different generation and quenching mechanisms of their corresponding excited states, i.e., OH(A2Σ+), N2(C3Πμ), and Ar(4p)/Ar(4s) in the argon plasma jet. Additionally, the formation of the diffuse plasma jet has been clarified by observing the discharge burning phase and solving the Poisson equation for the electric field distribution in an argon cylindrical dielectric-barrier discharge. The filamentary discharge deposits charged particles onto the dielectric. The positive surface charges in the positive half cycle induce a relatively high field in the local region close to the dielectric. The relatively high field and the high pre-ionization in this local region play a key role in initiating the diffuse positive corona. ? 2017 Author(s).Accession Number: 20172803923550 -
Record 367 of
Title:Superhydrophilic Antireflective Periodic Mesoporous Organosilica Coating on Flexible Polyimide Substrate with Strong Abrasion-Resistance
Author(s):Wang, Jing(1,2,4); Zhang, Cong(1,4); Yang, Chunming(3); Zhang, Ce(1,4); Wang, Mengchao(1,4); Zhang, Jing(1,2,4); Xu, Yao(2)Source: ACS Applied Materials and Interfaces Volume: 9 Issue: 6 DOI: 10.1021/acsami.6b14117 Published: February 15, 2017Abstract:Superhydrophilic antireflective periodic mesoporous organosilica (PMO) coating was prepared on flexible polyimide substrate via solvent-evaporation-induced self-assembly (SEISA) method, in which tetraethoxysilane (TEOS) and a special bridged silsesquioxane were used as reactants. The bridged silsesquioxane, EG-BSQ, was synthesized through the stoichiometric reaction between 3-glycidoxyporpyltrimethoxysilane (GPTMS) and ethylene diamine (EDA). Under the influence of surfactant, TEOS and EG-BSQ co-condensed and enclosed the ordered mesporous in the coating. The results of grazing-incidence small-angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) indicated that the mesopores belonged to a Fmmm orthorhombic symmetry structure. With increasing EG-BSQ concentration, the mesoporous structure in the PMO coating becomes more and more disordered because silica mesopore walls shrunk or collapsed during calcination and consequently the refractive index of PMO coating became larger. The antireflective (AR) PMO coating showed an optical transmittance of 99.54% on polyimide (PI) much higher than the 88.68% of bare PI. The water contact angle of PMO coating was less than 9.0°, which indicated the AR PMO coating was superhydrophilic. Moreover, the PMO coating showed an excellent mechanical property, the transmittance of the PMO coating displayed a very low loss of 0.1% after abrasion of 25 cycles by CS-10F wearaser. ? 2017 American Chemical Society.Accession Number: 20170803366295 -
Record 368 of
Title:High Temporal and Spatial Resolution Distributed Fiber Bragg Grating Sensors Using Time-Stretch Frequency-Domain Reflectometry
Author(s):Ahmad, Eamonn J.(1); Wang, Chao(1); Feng, Dejun(1,2); Yan, Zhijun(3,4); Zhang, Lin(3)Source: Journal of Lightwave Technology Volume: 35 Issue: 16 DOI: 10.1109/JLT.2016.2605401 Published: August 15, 2017Abstract:A novel interrogation technique for fully distributed linearly chirped fiber Bragg grating (LCFBG) strain sensors with simultaneous high temporal and spatial resolution based on optical time-stretch frequency-domain reflectometry (OTS-FDR) is proposed and experimentally demonstrated. LCFBGs is a promising candidate for fully distributed sensors thanks to its longer grating length and broader reflection bandwidth compared to normal uniform FBGs. In the proposed system, two identical LCFBGs are employed in a Michelson interferometer setup with one grating serving as the reference grating whereas the other serving as the sensing element. Broadband spectral interferogram is formed and the strain information is encoded into the wavelength-dependent free spectral range (FSR). Ultrafast interrogation is achieved based on dispersion-induced time stretch such that the target spectral interferogram is mapped to a temporal interference waveform that can be captured in real-time using a single-pixel photodetector. The distributed strain along the sensing grating can be reconstructed from the instantaneous RF frequency of the captured waveform. High-spatial resolution is also obtained due to high-speed data acquisition. In a proof-of-concept experiment, ultrafast real-time interrogation of fully distributed grating sensors with various strain distributions is experimentally demonstrated. An ultrarapid measurement speed of 50 MHz with a high spatial resolution of 31.5 μm over a gauge length of 25 mm and a strain resolution of 9.1 μ? have been achieved. ? 2016 IEEE.Accession Number: 20173404055414 -
Record 369 of
Title:Multiwavelength erbium-doped fiber laser based on an all-fiber polarization interference filter
Author(s):Wang, Hushan(1,3); Yan, Zhijun(1,2); Zhou, Kaiming(1); Song, Jiazheng(1); Feng, Ye(1); Wang, Yishan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10323 Issue: DOI: 10.1117/12.2263392 Published: 2017Abstract:We demonstrated a compact stable room-temperature multiwavelength erbium doped fiber laser by employing a 45° tilted fiber gratings (TFGs) based all-fiber polarization interference filter. Benefiting from the filter, the channel number, the linewidth, the uniformity and stabilization of the multiwavelength laser were greatly improved. The filter also worked as a polarizing functional device in nonlinear polarization rotation leading to multiwavelength operation. More than 60 wavelengths (within 3dB bandwidth) lasing with a linewidth of 0.03nm and a signal-to-noise ratio of 31dB were obtained. The wavelength spacing was 0.164nm agreeing with the value of the filter and it can be flexibly controlled by adjusting the length of the filter. ? 2017 SPIE.Accession Number: 20172003666459 -
Record 370 of
Title:Highly polarized multiwavelength er-doped fibre laser using all fibre lyot filter
Author(s):Zhao, Zihao(1); Li, Yue(1); Yan, Zhijun(1,2,3); Luo, Yiyang(1); Wang, Hushan(3); Sun, Qizhen(1,2); Liu, Deming(1); Zhang, Lin(2)Source: ICOCN 2017 - 16th International Conference on Optical Communications and Networks Volume: 2017-January Issue: DOI: 10.1109/ICOCN.2017.8121447 Published: November 27, 2017Abstract:A multiwavelength Er-doped fibre ring laser system using all fibre Lyot filter and highly nonlinear fibre was experimentally demonstrated, with degree of polarization up to 99.9% and 50 channels output. ? 2017 IEEE.Accession Number: 20181104913279 -
Record 371 of
Title:Refined-graph regularization-based Nonnegative matrix factorization
Author(s):Li, Xuelong(1); Cui, Guosheng(1,2); Dong, Yongsheng(1,3)Source: ACM Transactions on Intelligent Systems and Technology Volume: 9 Issue: 1 DOI: 10.1145/3090312 Published: August 2017Abstract:Nonnegative matrix factorization (NMF) is one of the most popular data representation methods in the field of computer vision and pattern recognition. High-dimension data are usually assumed to be sampled from the submanifold embedded in the original high-dimension space. To preserve the locality geometric structure of the data, k-nearest neighbor (k-NN) graph is often constructed to encode the near-neighbor layout structure. However, k-NN graph is based on Euclidean distance, which is sensitive to noise and outliers. In this article, we propose a refined-graph regularized nonnegative matrix factorization by employing a manifold regularized least-squares regression (MRLSR) method to compute the refined graph. In particular, each sample is represented by the whole dataset regularized with 2-norm and Laplacian regularizer. Then a MRLSR graph is constructed based on the representative coefficients of each sample. Moreover, we present two optimization schemes to generate refined-graphs by employing a hard-thresholding technique. We further propose two refined-graph regularized nonnegative matrix factorization methods and use them to perform image clustering. Experimental results on several image datasets reveal that they outperform 11 representative methods. ? 2017 ACM.Accession Number: 20173604115683 -
Record 372 of
Title:Theoretical research of influence of laser intensity fluctuation on imaging quality degradation of coherent field
Author(s):Cheng, Zhi-Yuan(1); Ma, Cai-Wen(1); Ma, Qing(2)Source: Wuli Xuebao/Acta Physica Sinica Volume: 66 Issue: 24 DOI: 10.7498/aps.66.244202 Published: December 20, 2017Abstract:The laser coherent field imaging system emits multiple beams of laser from earth to space, and laser scans remote space target by passing through turbulence atmosphere. Multi-beam laser intensity fluctuation caused by atmosphere turbulence is a key factor affecting high-resolution imaging quality of the coherent field imaging system. Aiming at solving the problem of imaging quality degradation caused by laser intensity fluctuation error, we discuss the mechanism of laser intensity fluctuation error influencing the imaging quality of laser coherent field high-resolution imaging system. The theoretical model about the relationship between laser intensity fluctuation factor and imaging quality is proposed for the first time. Firstly, the laser echo field signal error induced by laser intensity amplitude fluctuation factor is deduced according to laser transmitting atmosphere theory. Then adopting multi-beam phase closure arithmetic, the phase closure coefficient error is derived from the laser intensity fluctuation factor and laser echo field signal. The mechanism of disturbed laser echo signal influencing phase closure coefficient is investigated in detail. In the following, based on reconstructed spectrum theory, the model of imaging frequency spectrum error propagation, caused by laser intensity fluctuation factor, is proposed. Finally, we reveal the mechanism of laser intensity amplitude fluctuation factor influencing reconstructed imaging frequency spectrum and imaging quality. The correctness and validity of the theoretical model are verified in simulation experiment. In the three-beam laser coherent field imaging simulation experiment, the imaging quality is evaluated by the Strehl ratio of the image. Experimental result shows that the Strehl ratio is only related to the light intensity fluctuation of one of the three beams of laser, and the greater the fluctuation of laser intensity, the more serious the degradation of imaging quality is. The research draws the conclusion that the reconstructed imaging frequency spectrum and image quality are mainly affected by the laser intensity fluctuation of the second beam in the three-beam phase closure algorithm, regardless of other two laser intensity fluctuations. Thus, in order to restrain the degradation of imaging quality caused by laser intensity fluctuation, we only need to keep stable the laser intensity of the second beam but not all of the laser beams. In this paper, we reveal the mechanism of laser intensity fluctuation affecting high-resolution imaging quality in the three-beam laser coherent field imaging system. The research provides a theoretical basis for analyzing imaging quality degradation from the laser intensity fluctuation caused by atmospheric turbulence, and reasonably assigning the light intensity stability of multi-beam laser emitter to improve the imaging quality in laser coherent field imaging system. ? 2017 Chinese Physical Society.Accession Number: 20180804822645