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Segmentation and classification of high spatial resolution images based on Hölder exponents and Variance

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Geo-Spatial Information Science 2017年第1期20卷 39-45页

作者： Debasish Chakraborty Sourabh Singh Dibyendu Dutta Regional Remote Sensing Centre-East National Remote Sensing CentreISRONew TownKolkataIndia Department of Computer Science and Engineering SMITSikkimIndia

Pixel-based or texture-based classification technique individually does not yield an appropriate result in classifying the high spatial resolution remote sensing imagery since it comprises textured and non-textured regions.In this study,Hölder exponents(HE)and Variance(VAR)are used together to transform the image for measuring texture.A threshold is derived to segment the transformed image into textured and non-textured regions.Subsequently,the original image is extracted into textured and non-textured regions using this segmented image mask.Afterward,extracted textured region is classified using ISODATA classification algorithm considering HE,VAR,and intensity values of individual pixel of textured region.And extracted non-textured region of the image is classified using ISODATA classification algorithm.In case of non-textured region,HE and VAR value of individual pixel is not considered for classification for significant textural variation is not found among different classes.Consequently,the classified outputs of non-textured and textured regions that are generated independently are merged together to get the final classified image.IKONOS 1 m PAN images are classified using the proposed algorithm,and the classification accuracy is more than 88%.

关键词： High-resolution image texture segmentation Hölder exponents Variance contrast classification ISODATA

Sparse asymptotic minimum Variance based bearing estimation algorithm for a single vector hydrophone

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Chinese Journal of Acoustics 2022年第1期41卷 35-48页

作者： WANG Chao DA Lianglong HAN Mei SUN Qindong WANG Wenlong Navy Submarine Academy Qingdao 266199 Pilot National Laboratory for Marine Science and Technology Qingdao 266237

For underwater target detection using a single vector hydrophone,sparse asymptotic minimum Variance(SAMV)method is used to estimate the target bearing.The SAMV discretizes the entire scanning space and the target bearing is located at the position of the discrete direction.The SAMV algorithm utilizes the sparsity of the spatial signal to improve the estimation performance of the target bearing.Background noise level(BNL)of the bearing estimation of SAMV algorithm is lower than those of the conventional beam forming(CBF)method and minimum Variance distortionless response(MVDR)method for different signal noise ratios(SNRs).When the SNR is higher than 0 d B,the direction-finding error of this algorithm is less than 2°.Moreover,the SAMV algorithm has a better dimensional orientation resolution capability.The experimental results show that the SAMV algorithm gives a bearing and time recording map with a lower BNL,which effectively verifies the effectiveness of SAMV algorithm in terms of underwater target detection.

关键词： estimation algorithm Variance

Variance Analysis and Adaptive Sampling for Indirect Light Path Reuse

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Journal of Computer Science & Technology 2016年第3期31卷 547-560页

作者： Hao Qin Xin Sun Jun Yan Qi-Ming Hou Zhong Ren Kun Zhou State Key Laboratory of Computer Aided Design and Computer Graphics Zhejiang University Hangzhou 310058 China Microsoft Research Asia Beijing 100080 China

In this paper, we study the estimation Variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the coVariance of the reconstruction samples dominates the estimation Variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the coVariance. We also find that the coVariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the coVariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering Variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost.

关键词： Monte Carlo method global illumination Variance indirect light path reuse

Variational Quantum Eigensolver with Mutual Variance-Hamiltonian Optimization

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Chinese Physics Letters 2023年第1期40卷 9-13页

作者：陈彬琳张旦波 Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal UniversityGuangzhou 510006China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

The zero-energy Variance principle can be exploited in variational quantum eigensolvers for solving general eigenstates but its capacity for obtaining a specified eigenstate,such as ground state,is limited as all eigenstates are of zero energy Variance.We propose a Variance-based variational quantum eigensolver for solving the ground state by searching in an enlarged space of wavefunction and Hamiltonian.With a mutual Variance-Hamiltonian optimization procedure,the Hamiltonian is iteratively updated to guild the state towards to the ground state of the target Hamiltonian by minimizing the energy Variance in each iteration.We demonstrate the performance and properties of the algorithm with numeral simulations.Our work suggests an avenue for utilizing guided Hamiltonian in hybrid quantum-classical algorithms.

关键词： Hamiltonian Variance quantum

Intra-population genetic Variance for grain iron and zinc contents and agronomic traits in pearl millet

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The Crop Journal 2016年第1期4卷 48-54页

作者： Mahalingam Govindaraj Kedar N.Rai Ponnusamy Shanmugasundaram International Crops Research Institute for the Semi-arid Tropics (ICRISAT) Centre for Plant Breeding and Genetics Tamil Nadu Agricultural University

Crop biofortification is a sustainable approach for fighting micronutrient malnutrition in the world. The estimation of Variance components in genetically broad-based populations provides information about their genetic architecture, allowing the design of an appropriate biofortification breeding method for cross-pollinated crops such as pearl millet. The objective of this study was to estimate intra-population genetic Variance using self(S1) and half-sib(HS) progenies in two populations, AIMP92901 and ICMR312. Field trials were evaluated in two contrasting seasons(2009 rainy and 2010 summer; otherwise called environments) in Alfisols at ICRISAT, Patancheru. Analyses of Variance showed highly significant variation for S1 s and HS progenies, reflecting high within-population genetic variation for both micronutrients and other key traits. However, the HS showed narrow ranges and lower genetic Variances than the S1 for all of the traits. The micronutrients were highly positively correlated in S1(r = 0.77 to 0.86; P Variance component was different among populations for Fe and Zn contents across environments, with AIMP92901 showing a greater proportion of dominance and ICMR312 greater additive Variance for these micronutrients. The estimates of Variance(additive and dominance) were specific for each population, given their dependence on the additive and dominance effects of the segregating loci, which also differ among populations. The possible causes for such differences were discussed. The results showed that the expression of these micronutrients in pearl millet shows largely additive Variance, so that breeding high-iron hybrids will require incorporation of these micronutrient traits into both parental lines.

关键词： Genetic Variance Iron Micronutrient malnutrition Pearl millet Zinc

An interpolation decoupling method of multi-sensor information based on Variance

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An interpolation decoupling method of multi-sensor informati...

Energy Variance in Decoherence

The 2011 International Conference on Advanced Materials and Information Technology Processing(AMITP 2011)

作者： Ye Ting-dong Liu Gui-xiong Computer Department Guangdong Industry Technical College School of Mechanical & Automotive Engineering South China University of Technology

In order to solve decoupling problem of homogeneous multi-sensor information which couples with other sensor’s information, the paper proposed an interpolation decoupling method of multi-sensor inform

ISBN: (纸本)9783037851579

关键词： Interpolation Variance Decoupling Scale threshold multi sensor Variance Decoupling method information DECOUPLING Interpolation accuracy of measurement

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Chinese Physics Letters 2020年第3期37卷 1-4页

作者：袁子刚张新宇赵贺李彦超 College of Mathematics and Physics Beijing University of Chemical TechnologyP.O.Box 26Beijing 100029 Centre for Quantum Technologies National University of Singapore3 Science Drive 2Singapore 117543Singapore Center of Materials Science and Optoelectronics Engineering College of Materials Science and Opto-Electronic TechnologyUniversity of Chinese Academy of SciencesBeijing 100049

We study the effect of the initial-state energy Variance to the short-time behavior of the Loschmidt echo(LE) in a purely dephasing model. We find that the short-time LE behaves as a Gaussian function with the width determined by the initial-state energy Variance of the interaction Hamiltonian, while it is a quartic decaying function with the width determined by the initial-state energy Variance of the commutator between the interaction Hamiltonian and the environmental Hamiltonian when the initial state is an eigenstate of the interaction Hamiltonian.Furthermore, the Gaussian envelope in the temporal evolution of LE in strong coupling regime is determined by the inband Variance. We will also verify the above conclusion in the XY spin model(as environment).

关键词： Hamiltonian Variance interaction

Detecting Intensity Evolution of the Western North Pacific Super Typhoons in 2016 Using the Deviation Angle Variance Technique with FY Data

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Journal of Meteorological Research 2019年第1期33卷 104-114页

作者： Meng YUAN Wei ZHONG Institute of Meteorology and Oceanography National University of Defense Technology

This paper analyzes the complete lifecycle of super typhoons in 2016 in the western North Pacific(WNP) using the deviation angle Variance technique(DAV-T). Based on the infrared images from Fengyun(FY) satellites, the DAV-T enables quantification of the axisymmetry of tropical cyclones(TCs) by using the DAV values; and thus, it helps improve the capability of TC intensity estimation. Case analyses of Super Typhoons Lionrock and Meranti were performed to explore the distribution characteristics of the DAV values at the various stages of TC evolution. The results show that the minimum DAV values(i.e., map minimum values: MMVs) gradually decreased and their locations constantly approached the circulation center with enhancement of the TC organization; however, when a ring or disk structure was formed around a TC, significant changes in MMV locations were no longer observed. Nonetheless,when large-scale non-closed deep convective cloud clusters appeared at the early stage or the dissipation stage of the typhoon, the axisymmetry of the TC was poor and the MMV locations tended to lie in the most convective region rather than in the TC circulation center. Overall, the MMVs and their locations, respectively, exhibited a strong correlation with the TC intensity and circulation center, and the correlation increased as the TCs became stronger. Combined with the China Meteorological Administration BestTrack dataset(CMA-BestTrack), statistical analysis of all research samples reveals that the correlation coefficient between the MMVs and maximum surface wind speeds(Vmax) was –0.80; the root mean square error(RMSE) of relative distance between the MMV locations and TC centers was 140.3 km; and especially, when the samples below the tropical depression(TD) intensity were removed, the RMSE of the relative distance decreased dramatically to 95.0 km. The value and location of the MMVs could be used as important indicators for estimating TC intensity and center.

关键词： deviation angle Variance technique(DAV-T) axisymmetry super typhoon Fengyun(FY) satellites

The Sum and Difference of Two Constant Elasticity of Variance Stochastic Variables

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Applied Mathematics 2013年第11期4卷 1503-1511页

作者： Chi-Fai Lo Department of Physics Institute of Theoretical Physics The Chinese University of Hong Kong Hong Kong China

We have applied the Lie-Trotter operator splitting method to model the dynamics of both the sum and difference of two correlated constant elasticity of Variance (CEV) stochastic variables. Within the Lie-Trotter splitting approximation, both the sum and difference are shown to follow a shifted CEV stochastic process, and approximate probability distributions are determined in closed form. Illustrative numerical examples are presented to demonstrate the validity and accuracy of these approximate distributions. These approximate probability distributions can be used to valuate two-asset options, e.g. spread options and basket options, where the CEV variables represent the forward prices of the underlying assets. Moreover, we believe that this new approach can be extended to study the algebraic sum of N CEV variables with potential applications in pricing multi-asset options.

关键词： Constant Elasticity of Variance Stochastic Variables Probability Distribution Functions Backward Kolmogorov Equation Lie-Trotter Splitting Approximation