Circular Harmonic Minimum Average Energy Filter for the Multi-Distorted Invariant Correlation

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A New Method for Rotation and Brightness Invariant Pattern Recognition Based on Modified Multiple Circular Harmonic Expansions

A new method for rotation and brightness invariant pattern recognition was proposed by applying multiple circular harmonic expansions to the joint transform correlator. The amplitudes of the multiple orders of circular harmonic expansions made from a detecting image were synthetically modified to respond to the same auto-correlation peaks. These modified circular harmonic expansions were arranged in the input plane as reference patterns together with an arbitrary target pattern, and the correlation signals between them were calculated in the subtracted joint transform correlator. The fraction of the correlation-peak intensities between the target and the references were extracted as a new discrimination parameter. This new parameter performs pattern recognition under rotation and brightness invariance with good discriminability. Its high discriminability has been proved in computer simulations using the face image patterns of many individuals.     

相对论涡旋高次谐波的产生与调控理论研究

目前,具有螺旋相位波前和环状光强分布的涡旋光束已在光学领域获得了广泛应用,其产生与调控自然成了研究的热点。利用三维粒子模拟程序对双色拉盖尔高斯激光驱动固体等离子激发同时携带自旋角动量与轨道角动量的高次谐波的物理过程进行了研究,根据高次谐波产生过程中的光子能量与角动量守恒定律对其内在物理机制进行了理论分析,并讨论了对谐波阶次、偏振态（自旋角动量）以及拓扑荷数（轨道角动量）进行调控的方法。研究结果为开发高亮度、超短超快、短波长、自旋与轨道角动量可调控的涡旋光束辐射源提供了理论依据,在光学微操控、超分辨成像、光通信以及离子加速等领域具有较大的实际应用前景。     

修正振幅调制的光电混合圆谐联合变换相关器作旋转不变的目标检测

提出一种修正振幅调制的光电混合圆谐联合变换相关器作旋转不变的目标检测的实验系统。参考图像（即圆谐展开分量的实部和虚部）、圆盘状的局部偏置函数以及目标图像同时显示于输入面。此方法对联合功率谱作了修正,先将联合功率谱减去纯输入景物（含局部偏置函数）的功率谱和参考图像（含局部偏置函数）的功率谱,再加上局部偏置函数的功率谱,然后将所得修正的联合功率谱乘以振幅调制滤波函数。这种方法能产生比普通的圆谐联合变换     

使用同心多环阵提升声源定位鲁棒性*

房间混响带来的多径失真是影响声源波达方向估计精度的主要因素之一。应用于环形阵列的相干信号子空间方法可以降低相干反射声带来的不利影响。该方法对环形阵进行谐波展开,并利用环谐波域导向矢量的频率无关特性聚焦各频率下的空间相关矩阵。但单环阵列存在展开系数零点,这会导致严重的噪声放大而降低定位的鲁棒性。该文提出了一种环谐波域的最小模同心多环阵,来缓解系数零点处的噪声放大问题。设计了一套麦克风阵列系统,用于评估同心多环阵列定位的鲁棒性。仿真和实验结果均表明:与相同孔径和阵元数的单环阵相比,使用最小模准则设计的同心多环阵列可以显著提升混响场景下的声源定位的稳健性。     

用零阶圆谐波滤波器实现不变性图像分割

提出了一种新的，用零阶圆谐波滤波器相关进行图像分割的方法．相关峰的轮廓保持了输入图像的形状．这种方法具有平移不变、旋转不变和尺度不变的特点．并给出了计算机模拟的结果．     

The steady state response of a damped circular plate driven at a diameter

The steady state response of a damped circular plate transversely or rotationally driven at a diameter is determined by the series-type method. With the reaction force or moment acting along a diameter of a circular plate regarded as an unknown harmonic load, the response of the plate to the load is expressed by the Green function. The force or moment distribution along the diameter is expanded into Fourier series with unknown coefficients, and the simultaneous linear equations for the coefficients are derived by the restraint condition on the diameter. The dynamic response of the plate is determined by solving the equations. The method is applied to circular plates driven by a sinusoidally varying transverse deflection or angular rotation at a diameter, and the steady state response of the plates is studied.     

旋转不变振幅位相合成圆谐滤波器

提出了振幅位相合成圆谐滤器用于旋转不变模式识别，该滤波器的振幅是圆谐滤波器的振幅谱加偏移量后的逆函数，位相是圆谐滤波器的位相谱。计算机模拟实验证明，与传统的圆谐滤波器和纯位相圆谐滤波器相比，振幅位相合成圆谐滤波器具有更好的识别能力，能产生更尖锐的相关峰和更大的输出信噪比。     

Angular Momentum and Energy Structure of the Coherent State of a 2D Isotropic Harmonic Oscillator

The angular momentum structure and energy structure of the coherent state of a 20 isotropic harmonic oscillator were investigated. Calculations showed that the average values of angular momentum and energy (except the zero-point energy) of this nonspreading 20 wavepacket are identical to those of the corresponding classical oscillator moving along a circular or an elliptic orbit.     

Rotation-invariant pattern recognition using morphological fringe-adjusted joint transform correlation

We propose a rotation-invariant nonlinear correlator based on circular harmonic filter (CHF) and morphological Fringe-adjusted Joint Transform correlation (MFJTC). We refer to this correlator as a rotation-invariant MFJTC (RIMFJTC). Through computer simulation, we compare the output results of RIMFJTC with those of rotation-invariant MC (RIMC) and CHF when input scene is corrupted by salt-and-pepper noise, white additive Gaussian noise and cluttered background. Our results show that RIMFJTC yields higher discriminability, sharper and higher correlation peaks, and displays better stability against the above three kinds of noise than do the RIMC and common CHF.     

Rotational-InVariant pattern recognition using circular optical wavelet transform

An improved shift- and rotational-invariant filter using wavelet transform and circular harmonic filtering at the same time is proposed. Computer simulation has shown that this is better than using a phase-only circular harmonic filter in peak sharpness, discriminating ability, SNR and tolerance of position error of the filter. Furthermore, this filter possesses moderate diffraction efficiency.     

Rotation invariant pattern recognition with a volume holographic wavelet correlation processor

A volume holographic wavelet correlation processor for performing rotation invariant Pattern recognitionis suggested.It uses wavelet transform to get the digital edge extraction of the original object and a singlecircular harmonic component iS used as the matched filter to get good rotation invariance.The new filterused in this method is called wavelet circular harmonic component fllter (WCHCF).Simulation resultsvalidate the theory and the experiment to recognize human faces with any rotation angle shows the utilityof the newly proposed method.     

空间平移不变和角度受限下转动不变的特征识别与滤波器的设计

徐原能等人曾提出借助于circular harmonic expansion(圆谐波展开),设计空间平移不变和转动不变的滤波器系统,用于特征识别。本文在他们的基础上提出一种实现空间平移不变和在一定的角度范围内转动不变的特征识别方法,给出相应的滤波器设计具体公式。虽然转动不变的角度范围受到限制,但能够提高系统的信噪比,同时,不需要通过测量靶与待识别图象之间的相关函数的相位因子,来判定转动角度,而是代之直接测量相关函数的绝对值,由此推算转动角度。本文还列举一个具体的例子,来演示滤波器的设计方法,并与徐原能方案 关键词：     

含重金属硅化物SiM(M=Au,Ag,Cu)的从头算理论研究

在不同电子相关水平上基于相对论和非相对论赝势,对含重金属硅化物SiM(M=Au,Ag,Cu)的基态几何结构和光谱特性进行了研究,并讨论了电子相关效应和相对论效应的影响.结果表明:重金属硅化物SiM(M=Au,Ag,Cu)的基态电子状态是2Π.电子相关效应缩短了金属硅化物的键长,提高了分离能,谐振频率也增加,使SiM(M=Au,Ag,Cu)的结构变得更加紧凑,基态更加稳定.相对论效应加强了它的强度,使三种硅化物更加稳定.相对论作用的顺序为AuSi>AgSi>CuSi.     

Two-photon absorption and two-photon-induced absorption of some organic liquids at 347.15 nm

The two-photon absorption cross-sections and effective excited- state absorption cross-sections at 347.15nm of the organic liquids ethylene glycol, methanol, ethanol, tetrahydrofuran, glycerol, cyclohexane, 1,4-dioxane, 1,2-dichloroethane, dichloromethane, chloroform, dimethylsulfoxide, N,N-dimethylformamide, o-xylene, m- xylene, p-xylene and xylene (isomer mixture) have been determined using second harmonic picosecond pulses of a mode-locked ruby laser system. Linear and circular polarized pump pulse transmission measurements were performed to determine the two linear independent two-photon absorption susceptibility components. Linear polarized probe pulse transmission measurements after pump-pulse passage were carried out to determine excited singlet state relaxation times.     

Variational path integral approach to the ground state energy of artificial atoms

Artificial atoms in different confinement potentials are studied using the Jensen–Feynman variational approach. The density and pair correlation function of an harmonic model with statistics are analytically calculated and used to find the variational ground state energy in two and three dimensions. The results are compared with the numerical calculations and a good correlation is found.     

CORRECTED SOLVABILITY CONDITIONS FOR NON-LINEAR ASYMMETRIC VIBRATIONS OF A CIRCULAR PLATE

An investigation into non-linear asymmetric vibrations of a clamped circular plate under a harmonic excitation is made. We re-examined a primary resonance studied by Sridhar, Mook and Nayfeh, in which the frequency of excitation is near the natural frequency of an asymmetric mode of the plate. We corrected their solvability conditions and found that in the absence of internal resonance, the steady state response can have not only the form of standing wave but also the form of travelling wave, which is a remarkable contrast to their conclusion.     

Quantum frequency doubling based on tripartite entanglement with cavities

We analyze the entanglement characteristics of three harmonic modes,which are the output fields from three cavities with an input tripartite entangled state at fundamental frequency.The entanglement properties of the input beams can be maintained after their frequencies have been up-converted by the process of second harmonic generation.We have calculated the parametric dependences of the correlation spectrum on the initial squeezing factor,the pump power,the transmission coefficient,and the normalized analysis frequency of cavity.The numerical results provide references to choose proper experimental parameters for designing the experiment.The frequency conversion of the multipartite entangled state can also be applied to a quantum communication network.     

A self-consistent field for the H2 molecule

We investigate the simple harmonic oscillator in a 1D box, and the 2D isotropic harmonic oscillator problem in a circular cavity with perfectly reflecting boundary conditions. The energy spectrum has been calculated as a function of the self-adjoint extension parameter. For sufficiently negative values of the self-adjoint extension parameter, there are bound states localized at the wall of the box or the cavity that resonate with the standard bound states of the simple harmonic oscillator or the isotropic oscillator. A free particle in a circular cavity has been studied for the sake of comparison. This work represents an application of the recent generalization of the Heisenberg uncertainty relation related to the theory of self-adjoint extensions in a finite volume.     

Perturbative Analysis of Anharmonic Chains of Oscillators Out of Equilibrium

We compute the first-order correction to the correlation functions of the stationary state of a stochastically forced harmonic chain out of equilibrium when a small on-site anharmonic potential is added. This is achieved by deriving a suitable formula for the covariance matrix of the invariant state. We find that the first-order correction of the heat current does not depend on the size of the system. Second, the temperature profile is linear when the harmonic part of the on-site potential is zero. The sign of the gradient of the profile, however, is opposite to the sign of the temperature difference of the two heat baths.