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玉米近红外光谱在仿生模式识别中的特征提取方法研究 总被引:1,自引:0,他引:1
近红外光谱特征提取是近红外光谱定性分析的关键步骤,其质量直接影响定性分析结果。采用漫透射方法测量8个玉米品种的近红外光谱,经预处理后,分别采用PCA,ICA,PLS-DA和小波分解四种方法对光谱进行特征提取,并使用仿生模式识别方法建立了8个玉米品种识别模型,最后使用测试集数据进行模型测试。结论如下:使用PLS-DA方法进行特征提取后建立的模型正确识别率优于使用PCA,ICA和小波分解特征提取后建立的模型。 相似文献
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一种改进的无单元伽辽金方法 总被引:1,自引:0,他引:1
使用单位分解积分,对传统的无单元伽辽金方法进行改进.有限覆盖和单位分解是单位分解积分的数学基础,对单位分解积分进行了严格证明,并指出使用Shepard函数作为单位分解函数是一个很好的选择.数值实例表明,使用单位分解积分进行数值求积的无单元伽辽金方法是一种真正的无网格方法,与经典的背景网格积分相比具有更高的精度. 相似文献
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为了提高汽车夜间行驶安全性能,设计并实现了一套基于红外图像处理的夜视安全系统。使用被动式红外相机对车辆和行人进行红外成像以得到车辆前方行人和车辆的准确位置;测距必须确定对象的形心,对红外图像的灰度值进行判定区分行人和车辆,对行人使用中值空域滤波方法进行降噪,对车辆使用db4小波进行预处理,然后使用基于图像边缘的图像分割方法进行图像分割,使用最大类间方差评估确定分割结果,再进行区域提取得到形心坐标;使用小孔成像模型计算形心与本车的距离,提取本车速度、加速度参数计算理论碰撞时间,当理论碰撞时间小于时间阈值时进行声光告警,从而实现实时预警。系统使用DIR-384-P红外相机,系统算法使用PFGA实现,测试结果表明,经过标校和加固后,系统与目标存在5米距离时,车辆测距的误差率达到2.74%,行人测距的误差率低于3.9%,具有一定的实际应用价值。 相似文献
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紫檀属中的木材有很多属于名贵木材,不同树种之间十分相似。传统的木材识别方法多以木材解剖学为主,通过观察木材的切片结构特征对木材的树种进行判断,这类方法虽有较高的识别精度,但是其识别工艺较为复杂而且技术难度也相对较高。与木材解剖学相对应的是利用图像信息或光谱信息的木材树种识别方法,该类方法虽具有较为简单的识别工艺,但是在对同属相似木材树种进行识别时,往往不能够取得较好的识别效果。提出了一种基于木材切面光谱特征和纹理特征相融合的木材树种识别方法,该方法不仅识别工艺简单、自动化程度高,而且具有较高的识别精度。首先通过数码相机和光谱仪采集木材切面的图像信息和光谱信息,然后分别使用纹理特征提取方法和光谱特征提取方法提取两类特征的特征向量,接下来使用基于典型相关分析的特征级融合方法将这两个特征向量进行融合,最后使用支持向量机对融合后的特征向量进行分类识别。为了验证方法的有效性,以市场中常见的5种紫檀属树种的三个切面为研究对象,对这些木材树种进行了识别。实验结果显示,单独使用纹理特征的识别正确率最高为80.00%,单独使用光谱特征的识别正确率最高为94.40%,使用融合的特征最高的识别正确率可达99... 相似文献
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A. N. Ponyavina 《Journal of Applied Spectroscopy》1998,65(5):752-765
Results of theoretical studies of the interaction between optical radiation and partially ordered disperse media are reported.
In terms of the amplitude-phase screen model consideration is given to the concentration effects of whitening and darkening
in random close-packed systems of optically soft particles. The concentration dependence of transmission of close-packed systems
of coarse particles is described with the use of a small-angle solution of the stochastic finite-difference transfer equation.
The effects of coherent reirradiation occurring in close-packed monolayers of highly refracting particles are analyzed using
a quasicrystalline approximation of the theory of multiple wave scattering and the radial particle distribution function obtained
from a solution of the Percus-Yevick equation. This approach extended to multilayer systems is used to describe formation
of forbidden photon zones in transmission spectra of one- and three-dimensional disperse systems with a high degree of ordering.
Results of quantitative calculations are shown to agree well with experimental data. The possibility of using established
regularities for optimization of spectral characteristics of selective elements based on spatially ordered disperse systems
with different structural organization is discussed.
Institute of Molecular and Atomic Physics of the National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072,
Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 721–733, September–October, 1998. 相似文献
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J. Píchal Y. Klenko 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):271-279
Plasma treatment of textile fabrics is investigated as an alternative to the environmentally hazardous wet chemical fabric
treatment and pretreatment processes. Plasma treatment usually results in modification of the uppermost atomic layers of a
material surface and leaves the bulk characteristics unaffected. It may result in desirable surface modifications, e.g. surface
etching, surface activation, cross-linking, chain scission and oxidation. Presented paper contains results of the applicability
study of the atmospheric pressure dielectric discharge (ADBD), i.e. dielectric barrier discharge sustaining in air at atmospheric
pressure and ambient temperature for synchronous treatment of several sheets of fabric. For tests sheets of polyester fabric
were used. Effectivity of the modification process was determined with hydrophilicity measurements evaluated by means of the
drop test. Hydrophilicity of individual sheets of fabric has distinctly increased after plasma treatment. Plasma induced surface
changes of textiles were also proven by identification of new functional groups at the modified polyester fabric surface.
Existence of new functional groups was detected by ESCA scans. For verification of surface changes we also applied high-resolution
microphotography. It has shown distinct variation of the textile surface after plasma treatment. Important aspect for practical
application of the plasma treatment is the modification effect time-stability, i.e. time stability of acquired surface changes
of the fabric. The recovery of hydrophobicity was fastest in first days after treatment, later gradually diminished until
reached almost original untreated state. 相似文献
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V. A. Tolkachev 《Journal of Applied Spectroscopy》1998,65(5):643-658
A number of phenomena that determine the nature of the fluorescence of free complex molecules and the possibility of its analytical
application are considered. Attention is specially paid to the specific features of the energetics of radiationless transitions,
the role of statistical factors in the formation of spectral properties and the interrelationship among the luminescence-spectrum
characteristics of rarefied vapors of complicated molecules, and the processes of energy transfer in collisions. The properties
of polarized fluorescence of hot and jet-cooled vapors, the processes of relaxation of anisotropy in time and during collision
reorientation, and transfer of anisotropy in photodisintegration are analyzed.
Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 620–634, September–October, 1998. 相似文献
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A photorefractive phase-conjugate mirror with linear absorption is examined. An objective of this study is to identify possible effects of absorption on the self-oscillation conditions of the mirror and the properties of the excited conjugate wave. It has been found that self-oscillation is still possible in the presence of absorption. However, the coupling coefficient required for self-oscillation must increase in magnitude with increasing absorption coefficient to counteract the depressing effects of absorption. A consequence of self-oscillation in the presence of absorption is enhancement of the mirror reflectivity. A parametric study of the absorption-enhanced mirror is presented.The authors wish to acknowledge the contributions of Dai Sieh during the initial phase of this study. The work that he completed as part of his Master of Science thesis was an important element in our study of PCM reflectivity enhancement. The authors also acknowledge the assistance of Sahaid Rauf in carrying out some of the numerical solutions of Eq. 10, the governing equation of the self-oscillatory modes. 相似文献
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S. N. Vladimirov 《Russian Physics Journal》2006,49(11):1204-1214
A number of debatable problems of modern nonlinear physics are discussed. A classification of deterministic systems with chaotic
behavior by the degree of openness and type of motion is suggested. Examples of dynamic systems illustrating the consistency
of this classification are presented, and special features of functioning of these systems and problems of quantitative estimation
of the degree of randomness are considered. A strict definition of quasi-deterministic chaos is given.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 49–58, November, 2006. 相似文献
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An algorithm is proposed for integrating linear partial differential equations with the help of a special set of noncommuting linear differential operators — an analogue of the method of noncommutative integration of finite-dimensional Hamiltonian systems. The algorithm allows one to construct a parametric family of solutions of an equation satisfying the requirement of completeness. The case is considered when the noncommutative set of operators form a Lie algebra. An essential element of the algorithm is the representation of this algebra by linear differential operators in the space of parameters. A connection is indicated of the given method with the method of separation of variables, and also with problems of the theory of representations of Lie algebras. Let us emphasize that on the whole the proposed algorithm differs from the method of separation of variables, in which sets of commuting symmetry operators are used.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 95–100, April, 1991. 相似文献
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B. Šesták 《Czechoslovak Journal of Physics》1972,22(4):270-285
After a historical survey of crystal plasticity the rôle of dislocations in plastic deformation of metals is outlined. The theory of plastic deformation in metal single crystals before the impact of transmission electron microscopy is described. Recent experimental results on glide and workhardening in single crystals of b.c.c. metals are reviewed and explained by a simple dissociation model of the screw-dislocation cores. A relative success of this explanation together with calculations of atomic structure of dislocation cores support the conclusion that different structures of screw dislocation cores are responsible for both differences and similarities between plastic behaviour of f.c.c. and b.c.c. metals. Further developments in the field of metal crystal plasticity by modern experimental techniques (transmission electron microscopy of deformed crystals in the stress-applied state, magnetic studies of dislocations in ferromagnetic crystals) and by atomic calculations of defect configurations are discussed.Na Slovance 2, Praha 8, Czechoslovakia.Invited paper presented on a plenary session of the First European Conference on the Physics of Condensed Matter organized by the Board of the Condensed Matter Division of E.P.S., in Florence on 14–17 September 1971 (Chairman: Prof. S. F. Edwards; Schuster Laboratory, University of Manchester). 相似文献
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M. A. Lapik 《Russian Journal of Mathematical Physics》2006,13(1):119-121
The equilibrium set, in the form of an interval on the real line, of the potential of an extremal measure for some energy
minimization problem is studied for the energy functional with the logarithmic kernel provided that the external field exists.
The minimum of the functional is sought on a set of measures bounded by a given measure. In particular, we prove that, under
a special dependence of the external field on time, the ends of the interval of equilibrium satisfy a system of partial differential
equations, the so-called continuum limit of the Toda lattice. Another result of the paper is a system of integral equations
for the ends of the interval of equilibrium.
Dedicated to the memory of B. M. Levitan
Supported by RFBR grants nos. 05-01-00522 and NSh-1551.2003.1, by Program No. 1 of the Branch of Mathematics, Russian Academy
of Sciences, and by INTAS project no. 03-51-6637. 相似文献
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This report describes an investigation of the influence of coating of invar foil with various materials on the sideband and collapse effects caused by an applied r.f. magnetic field. It is shown that coating of invar foil with nonmetallic materials causes a decrease of the r.f. sideband effect without affecting the r.f. collapse effect. Coating with metallic materials reduces both r.f. effects because of screening due to the r.f. field. The separation of the r.f. sideband and collapse effects due to coating allows us to distinguish the different origins of these effects, and suggests that the r.f. sidebands are of magneto-acoustic origin, while the r.f. collapse is of purely magnetic origin. 相似文献
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M. R. Cherkasov 《Optics and Spectroscopy》2016,120(6):827-834
The general theory of relaxation spectral shape parameters in the impact approximation (M. R. Cherkasov, J. Quant. Spectrosc. Radiat. Transfer 141, 73 (2014)) is adapted to the case of line broadening of infrared spectra of ammonia. Specific features of line broadening of parallel and perpendicular bands are discussed. It is shown that in both cases the spectrum consists of independently broadened singlets and doublets; however, the components of doublets can be affected by collisional interference. The paper is the first part of a cycle of studies devoted to the problems of spectral line broadening of ammonia. 相似文献