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Quaternion based joint DOA and polarization parameters estimation with stretched three-component electromagnetic vector sensor array

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Journal of Systems Engineering and Electronics 2017年第1期28卷 1-9页

作者： Jichao Zhao Haihong Tao National Laboratory of Radar Signal Processing Xidian UniversityXi’an 710071China

The three-component electromagnetic vector sensor (EMVS) consisting of co-centered orthogonally oriented x-dipole, z-dipole and z-loop is considered. In order to make full use of the spatial aperture of each component, the original uniform linear three-component EMVS array (ULTEA) is stretched into one half-wavelength spaced uniform linear loop subarray (ULLSA) along the z axis, and one sparse uniform linear co-centered orthogonally oriented dual-dipole (CODD) subarray (SULCSA) along the x axis. Then, a generalized rotation invariance based quaternion multiple signal classification (GRIQ-MUSIC) algorithm is presented for direction of arrival (DOA) and polarization parameters estimation. According to the proposed algorithm, the elevation angles are firstly estimated based on the half-wavelength spaced ULLSA. Then the polarization phase differences and azimuth angles are obtained based on the coupling relationship between the angle domain and polarization domain, but the azimuth angles are in coarse-resolution since the array aperture is not utilized. Next, the SULCSA is used to re-estimate the azimuth angles in fine-resolution, and the ambiguity problem can be resolved by the least square method. Finally, based on the estimated elevation angles, azimuth angles and polarization phase differences, the corresponding auxiliary polarization angles can be estimated by N times one-dimensional parameter search, where N is the sources number, and the parameters are matched automatically. Based on the GRIQ-MUSIC algorithm, the high dimensional parameters search problem of the conventional Q-MUSIC algorithm is simplified to a one-dimensional parameter search problem, thus the proposed algorithm not only reduces the computation complexity considerably, but also avoids the performance degradation caused by the failure in parameters pairing. The simulation examples demonstrate the effectiveness and feasibility of the proposed algorithm. ? 1990-2011 Beijing Institute of Aerospace Information.

关键词： Computer music Direction of arrival Least squares approximations Polarization Wavelet analysis

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Investigation of self-adaptive algebraic tomography for gas reconstruction in larger temperature range by multiple wavelengths absorption spectroscopy

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Chinese Optics Letters 2014年第12期12卷 52-58页

作者：李宁吕晓静翁春生 National Key Laboratory of Transient Physics Nanjing University of Science and Technology

We develop a self-adaptive algebraic tomography algorithm （SAATA） to investigate the simultaneons reconstruction of concentration and temperature distributions in larger temperature range from two views. The simplified optical arrangement with fewer projections is realized by extension of spectral information at multiple wavelengths, resulting in great potential in applications of practical combustion diagnosis. Tile results show SAATA can perform much better reconstructions in 300 3000 K temperature range than genetic simulated annealing algorithm and least-square orthogonal-triangular decomposition method with two- wavelength scheme. More phantoms are created to demonstrate the capability of SAATA to capture the peaks and adapt for both flat and sharp temperature distributions. Meanwhile, the advantage of high stability ensures better reconstruction performance at noise levels from 0.1% to 10% in projections.

关键词： Absorption spectroscopy Algebra Algorithms Least squares approximations Simulated annealing Temperature distribution Tomography

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Research on error compensation method for dual-beam measurement of roll angle based on rhombic prism(Invited Paper)

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Chinese Optics Letters 2014年第7期12卷 24-27页

作者：张桐冯其波崔存星张斌 Key Laboratory of Luminance and Optical Information Technology of Ministry of Education Beijing Jiaotong University

The fabrication deviation of prisms and the error crosstalk are two major factors that produce serious systematic errors in dual-beam roll measurement based on a rhombic prism, and an error compensation method is put forward in this letter to reduce these systematic errors. The rotation matrix, reflection matrix, and refraction matrix are used to calculate and obtain the mathematical relationship model of the roll angle as well as the fabrication deviation of prism and error crosstalk. The fabrication deviation can be obtained through comparison experiments and using the least square method. In this way, the systematic error of the roll measurement caused by fabrication deviation of prism and error crosstalk can be eliminated theoretically. The experimental results show that the maximum error of the roll angle measurement reduces evidently to 3.5″ from the previous 347.2″ after compensation.

关键词： Crosstalk Error compensation Fabrication Least squares approximations Systematic errors

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Simultaneous determination of ternary cephalosporin solutions by Raman spectroscopy

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Chinese Optics Letters 2013年第13期11卷 80-82页

作者：李重阳林旺邵洋帆冯远明 Department of Biomedical Engineering College of Precision Instrument and Optoelectronics EngineeringTianjin Key Laboratory of Biomedical Detecting Techniques and InstrumentsTianjin University

Cephalosporins are widely used as veterinary and human antibiotics. However, cephalosporin abuse is harmful to human health and causes allergic reactions or antibiotic resistance. We investigate a method fea- turing Raman spectroscopy and chemometrics to quantify mixture solutions of three typical cephalosporins, namely, ceftriaxone, cefotaxime sodium, and cefazolin sodium. Partial least-squares regression models are built on spectral data that are preprocessed by various methods. With prediction relative errors within 5% and high correlation coefficients of 0.998, we demonstrate that Raman spectroscopy combined with multivariate analysis is feasible for use in the quantitative determination of cephalosporin solutions. OCIS codes： 300.6450. 070.4340. 070.4790.

关键词： Least squares approximations Raman spectroscopy Regression analysis Sewage treatment plants

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Quadric surface projection model for fish-eye cameras

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Chinese Optics Letters 2012年第1期10卷 28-31页

作者：孟甜甜蒋金涛杨鸣 Faculty of Information Science and Engineering Ningbo University Ningbo 315211 China Zhejiang High-tech Medical Optoelectronic Equipment Research and Development Center Ningbo University Ningbo 315211 China

The curved surface projection model in fisheye image correction algorithm is presented. To analyze the causes of distortion in existing models, we establish an ideal surface projection model and compare its surface with the surfaces of existing models. Subsequently, feature points are obtained on the ideal surface according to the relationship of coordinates of fish-eye image points and their ideal three-dimentional （3D） points. Finally, the least square method is used to obtain a quadrie surface and presents a quadric surface projection model. The experiment shows that the corrected image of the new model is more similar to the actual scene than the corrected images of previous models.

关键词： Image reconstruction Least squares approximations

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A new analytical edge spread function fitting model for modulation transfer function measurement

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Chinese Optics Letters 2011年第3期9卷 37-40页

作者：李铁成冯华君徐之海 State Key Laboratory of Modern Optical Instrumentation Zhejiang University

We propose a new analytical edge spread function （ESF） fitting model to measure the modulation transfer function （MTF）.The ESF data obtained from a slanted-edge image are fitted to our model through the non-linear least squares （NLLSQ） method.The differentiation of the ESF yields the line spread function （LSF）,the Fourier transform of which gives the profile of two-dimensional MTF.Compared with the previous methods,the MTF estimate determined by our method conforms more closely to the reference.A practical application of our MTF measurement in degraded image restoration also validates the accuracy of our model.

关键词： Fourier transforms Image reconstruction Least squares approximations Optical transfer function

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Accuracy and analysis of long-radius measurement with long trace profiler

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Chinese Optics Letters 2011年第10期9卷 76-78页

作者：叶海仙杨李茗 Chengdu Fine Optical Engineering Research Center

The long trace profiler （LTP） is proposed to measure radius of curvature （R） and surface figure of a longradius spherical surface in an optical shop. Equipped with a motorized rotary stage and a two-dimensional tilt stage, the LTP scans the full aperture and calculates the absolute radius of curvature of each scanning line based on the least square method. Nonlinear error and manufacture error difference between center and the edge are obtained by comparing R results. The R-limit is validated and expressed as D/R, where D is the aperture of the mirror under test. A full-aperture three-dimensional figure is also reconstructed based on triangle interpolation.

关键词： Least squares approximations Optical testing Trace analysis

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Real-time restoration of rotational blurred image using gradient-loading

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Chinese Optics Letters 2008年第5期6卷 334-337页

作者：韩超阳李建勋陈萧朱振幅 Department of Automation Shanghai Jiao Tong University Optical Signature of Targets and Environments Key Laboratory of National Defense Science and Technology

The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.

关键词： Chlorine compounds Constrained optimization Curve fitting Degradation Geodesy Least squares approximations Repair Restoration Signal to noise ratio

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Determination of human skin optical properties in vivo from reflectance spectroscopic measurements

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Chinese Optics Letters 2007年第3期5卷 181-183页

作者：杨洪钦谢树森李晖陆祖康 Key Laboratory of Optoelectronic Science and Technology for Medicine (Fujian Normal University) Ministry of Education and Institute of Laser & Optoelectronics TechnologyFujian Normal University State Key Laboratory of Modern Optical Instrumentation Zhejiang University

A novel approach has been proved to quickly and non-invasively determine the optical properties of human skin in vivo. It is based on the diffuse reflectance approximation model and subjected to the well established library of absorption spectra of water and hemoglobin. Under the nonlinear least-square algorithm, fitting the measured spectra in the range of 400--1000 nm to the diffusion approximation model, the reduced scattering coefficient and absorption coefficient of skin tissue can be quickly determined in vivo. The results show that this method is convenient and suitable for the real-time clinical application.

关键词： Absorption spectra Least squares approximations Light reflection Optical properties

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Measurement of borneol based on infrared spectrometry

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Chinese Optics Letters 2005年第2期3卷 116-118页

作者：谷筱玉汪曣孙惠丽徐可欣 State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University Tianjin 300072

The infrared spectrometry contains multiple information of the sample, and it is easy to be applied to online measurement. To Chinese medicine, this technology can improve the standard of quality control and accelerate the modernization course. In this paper, we investigate the spectral characteristics of borneol, an effective ingredient in many Chinese medicines. The following results are achieved. In middle infrared （MIR） region, utilizing the linear relationship between absorption and concentration, the concentration of borneol with relative error within 4.30% in the strongest absorption region （2950-2970 cm^-1） is measured; in near infrared （NIR） region, the predicted concentrations of borneol are calculated by using partial least squares （PLS） regression analysis, in which the wavelengths are selected by genetic algorithm （GA） from the absorption bands of borneol in NIR region. The predicted relative error of calibration model is less than 2%. This result shows that PLS regression analysis combining genetic algorithm is a good method to improve prediction and reduce data in NIR region.

关键词： Calibration Genetic algorithms Least squares approximations Medicine Quality control Standards

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